A forklift is a special warehouse equipment designed to perform loading and unloading operations, transportation and storage of various goods. The loader device is a well-coordinated system, including a mass of components and additional equipment. What components are included in the forklift device, how does it work?
Loader design
Rich is being issued today the lineup forklifts. The design of different models may vary.
But, for the most part, the general device of a forklift implies the presence of the following components and assemblies:
- engine;
- rechargeable batteries (relevant for electric models);
- chassis;
- tires;
- brake mechanisms;
- lifting device;
- control system;
- hanging equipment.
Let us analyze in more detail the functional purpose and features of the key components of the forklift type device.
Engine
Most main element forklift devices (diesel or electric) - a power unit, it is also an engine. Today, forklifts are produced, equipped with one of two types of engines: electric or internal combustion (ICE). The latter, in turn, are divided into diesel, gasoline and gas. Some manufacturers offer models with hybrid powertrains, which allows you to work on different types of fuel. Most loaders used in European countries, equipped with gas or electric motors. This is due to the economy and environmental friendliness of this technique.
Often, forklift companies use engines from third-party manufacturers in their equipment. So, most often, forklifts are equipped with engines from Nissan or GM.
Let's analyze a few of the most popular models engines of these manufacturers and their characteristics:
The electrical circuit of the loader is the basis of the equipment control system. This is a complex of electronic components, including microprocessors, controllers and other parts, providing automatic or semi-automatic control of all forklift units, and, above all, the engine.
lifting device
The device of a forklift truck of any model necessarily implies the presence of a special unit responsible for lifting the load. The standard type loaders produced today are capable of lifting loads by 8 m. There are also specialized high-altitude cranes, maximum height whose lifting reaches 18 m. Lifting loads to a considerable height is associated with a lot of dangers. To reduce risks, manufacturers install special systems on their equipment that protect against vibration and level the effect of the unevenness of the site on which the loader operates. Due to this, the weight of the mast is reduced, its structure becomes more rigid and durable.
Loading units have masts that lift loads by means of special hydraulic cylinders. The loader's hydraulic circuit ensures smooth lifting and high security during machine operation. Models with retractable masts do not have a unit that is responsible for tilting the mast, since the center of gravity of these units shifts so much that the tilt would simply lead to a rollover. These models of loaders are equipped with tilting forks.
Tires
Forklifts can be used in a wide variety of conditions. The machines are used both in warehouses with a flat floor and in open areas, sometimes without any coating at all, which is especially important for construction sites. In manufacturing plants, there are often metal chips on the floor, on which forklifts have to move.
Therefore, they are used different kinds tires, selected based on the conditions of use:
- pneumatic;
- bandage;
- superelastic.
Pneumatic tires are similar in design to automobile tires, but reinforced with additional cord layers. Allows the use of loading equipment on various surfaces. Can be used on hard ground snow covered surface. A layer of air provides smoothing of irregularities, which has a positive effect on the service life of the transmission system.
Bandage tires are made from special material containing rubber, and a metal inner ring. Designed for use on flat surfaces. They have excellent strength, can be subjected to significant loads.
Superelastic tires are a combination of the two options discussed above. If necessary, they can be replaced with pneumatic ones. The design of such tires involves the presence of 3 layers of a substance containing rubber. The inner layer is designed to fix the tire on a steel disc rim. The middle layer performs a shock-absorbing function. The last layer can have a pattern. If there is no pattern, the use of such tires is allowed only on hard, even surfaces.
Most modern loaders use tires from the manufacturers SOLIDEAL (Belgium, produces all types of tires) or Advance (China, the main specialization is the manufacture of superelastic tires).
construction loader - This is a type of self-propelled load-lifting equipment of discontinuous action. Its main working body is a lifting mechanism with an installed bucket, forks, or other lifting device. The main purpose is lifting, moving, loading or unloading, storage of medium-sized cargo. He is able to combine the above operations to increase productivity, which also depends on the maneuverability and skill of the operator.
A loader, like a crane, belongs to lifting equipment, but, unlike it, it is capable of transporting goods over long distances. It is able to serve warehouses, construction sites, perform work in cramped conditions, for example, unload covered wagons, or store goods on racks. Autonomous movement and work, high mobility and ergonomics make it universal machine, capable of performing the tasks of cargo transportation at a construction site. The functionality of the loader is expanded due to the presence of a large number of load gripping devices and other equipment.
There is the following classification of loaders:
For maximum payload:
Light load capacity 1 - 4 t;
Average load capacity 4 - 10 t;
High load capacity 10 - 16 t;
Ultra-high load capacity - from 16 tons and above.
According to the type of lifting device, construction loaders are divided into three types:
1. . Its lifting device is a mast, consists of several sections inserted one into one, a hydraulic cylinder and a carriage. It moves up and down the mast, raising and lowering the load, and a load gripping body is attached to it.
2. . lifting device represents space frame, fixed at one end on the horizontal shaft of the front of the machine, a lifting hydraulic cylinder is installed in the middle, and a load gripping device is installed at the other end. There are two designs front loader: with front linkage and with the possibility of rear unloading of the lifting device.
3. . Its load gripping device is mounted on a telescopic boom. It is attached to the frame on the shaft, and can be lowered and raised using a hydraulic cylinder. Depending on the design, it can be with a swivel or non-swivel boom.
According to the location of the lifting device:
A) frontal - the lifting mechanism is located in front of the loader. It has the greatest distribution because of its functionality.
B) side - the mechanism for lifting the load is located on the side. Performs specific tasks in the maintenance of warehouses with narrow aisles and long loads. Basically, it is equipped with a fork load gripping body.
By type of main power unit:
Petrol / gas;
Electrical;
Diesel / gas-diesel.
By type of chassis:
Caterpillar loader (can be equipped with both rubber and iron tracks);
The wheel loader, in turn, is divided into two categories according to the type of installed wheels and their number:
Type of wheels: chamber-pneumatic, not pierced-superelastic and bandage made of solid rubber tape;
Number of wheels: three-wheel, four-wheel, six or more wheels.
According to the maximum height to which it is possible to lift the load, they are divided into two groups:
Up to 4 meters;
Above 4 meters.
A modern loader consists of a self-propelled chassis with the following units installed on it:
hydromechanical lift with interchangeable working bodies, counterweight, internal combustion engine or electric motor, transmission, running gear, operator's cabin with controls and hydraulic system.
Fork (mast) lifting mechanism consists of the main frame, fastened to the frame of the forklift truck on a swivel joint, and with the help of a hydraulic cylinder, its angle of inclination is changed forward up to 8 ° and back up to 15 °. The main frame of the mast carries a movable frame, which is raised or lowered by the operation of the central hydraulic cylinder. At the top of the mast are two sprockets through which the chains are thrown. They are attached at one end to the fixed main frame of the lifting mechanism, and at the other - to the carriage with a gripper.
The forklift can be equipped with a mast of the following design:
Duplex or two-section;
Mast - duplex with the possibility of free running of the carriage - the design is similar to the duplex, an additional third cylinder is installed, which increases the height of free lifting (lifting the lifting carriage, without moving the second section of the mast);
Triplex or three-section - all structures of this type are equipped with a free carriage carriage.
Loaders having a free-wheel duplex or triplex mast design, and having a maximum mast height of 2.2 m, are called: "car loader". The triplex mast is capable of lifting the load to the highest height in comparison with other types. This type of equipment is used to move calibrated cargo on pallets in production or in a warehouse.
Let's take a look at one of the most common Z-shaped linkage hoist devices. At the front end of the boom, on a swivel, a front bucket is attached. It has the ability to change the slope using a hydromechanical mechanism consisting of one or two hydraulic cylinders and levers attached to the bucket. The hydraulic cylinders themselves rest on the frame and are hinged. In such a mechanism, the fulcrum of the lever is between the points of application of forces, this creates an increased force on the edge of the bucket. Rubber seals on the linkage and boom pivot joints keep grease in place and prevent moisture, dirt and dust from getting inside. This increases the durability of the swivel joints, and reduces labor costs for their maintenance.
telescopic loader equipped with a multi-section boom-telescope. An increase in the length of the boom occurs by extending the sections with the help of an internal hydraulic cylinder. At the end of the boom, a lever mechanism with a hydraulic cylinder is installed to change the angle of inclination of the load gripping body.
A loader with a swivel telescopic boom consists of a base chassis with a running gear and a turntable mounted on it. The boom itself, the operator's cabin, the power unit, the counterweight, and the hydraulic system are mounted on it. The fixed boom, together with the rest of the equipment of the loader, is mounted on the chassis of the special equipment. The advantage of a loader with a telescopic boom is an incomparable maximum lifting height (the average among existing models is 18 m) and a large load capacity (the most common models lift about 5 tons).
Diesel and gasoline engines known for their reliability, ease of execution and maintainability. But they are almost impossible to operate indoors due to the emitted exhaust gases and high noise levels. The situation can be corrected by installing an expensive cleaning filter.
The gas engine is structurally similar to gasoline engine. It is not only more profitable in terms of fuel costs, but also has a lower level of emissions. The gas powered forklift can operate freely in a poorly ventilated building. It is equipped with replaceable cylinders with a capacity of 27 to 50 liters.
The forklift with an electric motor is designed for indoor use. Such machines are advantageous due to lowest cost fuel, low noise level and absence of gaseous emissions into the atmosphere. But they cannot be operated at low temperatures - batteries have a limited resource and a high cost.
Information instruments and controls are located in the operator's cab. Due to the danger of operating the machine, special safety requirements for the driver are set for the cab. It must be strong enough to withstand a fall of a forklift or load. In the case of handling bulk materials, it must protect the operator from dust, or the possibility of injury from solids. The cab must have a heating or air conditioning system to operate in hot or cold climates, respectively.
The specifics of the loader application and its purpose determine the design of the running suspension. In particular, an important parameter is the number of wheels. Tricycle models have two drive wheels and a single or twin wheel. This design is excellent for working in narrow spaces where maneuverability is required. The disadvantage of the three-wheel loader is the reduced carrying capacity and operation only on flat surfaces, due to lower stability. Four-bearing models have other advantages and disadvantages. They are not as manoeuvrable, but they are able to lift a larger load, and operate outdoors, drive long distances on a bumpy road.
When purchasing a loader, the owner should think about what surface the equipment will drive on. Suitable for driving on uneven surfaces pneumatic tires with good damping properties. They will protect the suspension components from rapid wear. For driving on a flat surface with the presence of small, hard fractions, expensive, wear-resistant superelastic tires can be used. Due to the low profile, they have almost no cushioning, and quickly wear out the chassis fasteners. The common solid rubber belt tires can also be used on slightly uneven paved roads. They offer balanced performance, value for money, and will satisfy any practical small loader owner.
To capture the load, loaders are equipped not only with simple forks or buckets of various sizes. Modern technology can be equipped with complex devices, ranging from clamshell, two-bucket grabs to a mini excavator unit or a hydraulic pit drill. Forklift manufacturers offer a very wide range of attachments. They satisfy the needs in any field: construction, agriculture and forestry, cleaning of the territory, etc. The picture shows only some examples of equipment.
Modern forklifts are self-propelled lifting and transport equipment, the purpose of which is to minimize the use of manual labor both in warehouses with a large cargo flow and where small loading and unloading operations are required. What is the device of this miracle helper?
The forerunners of modern forklifts, which appeared at the beginning of the last century, did not have a transmission, a brake system, and no one had heard of hydraulics. Primitive steering made the loader uncomfortable and unsafe. Based on all these nuances and using the experience of industrial production of cars and various lifting devices, designers and engineers changed the design of forklifts and step by step created more advanced models.
Forklift evolution
In the very first loaders on which internal combustion engines were introduced, either stepped (a system of wheels and gears) or continuously variable (belt) transmissions were installed. The rapid wear of the working surfaces at the points of contact prompted the developers to use a hydraulic transmission in the forklift device, which transmits and converts mechanical energy with the help of a liquid.
Photo source: yale.com
The first experience of using hydraulics was connected with the braking system. But the hydraulic drive showed its main advantages in the operation of lifting mechanisms. The design of the first generation of forklifts featured a fixed vertical mast and fork carriage, which the operator could control with a winch and steel cables. In the late 1920s, Yale introduced a carriage that included a hydraulic gripper and tilted forks. In the middle of the next decade, the center of the loader mast was equipped with a hydraulic cylinder, which was controlled by a hydraulic pump combined with a drive motor. Thanks to this cylinder, the operator could adjust the lifting of the load. And to raise the mast and fork carriages, they began to use chains instead of steel cables.
At the end of the 30s, forklift trucks appeared, in the device of which an inclined type mast was used. The hydraulic mechanism regulated the angle of inclination of such a mast. In the 1950s, the hydraulic sideshift of the forklift mast was included in the general consumption. Francis W. Davies proposed to replace the mechanical steering mechanism with a hydraulic drive system in the mid-1950s.
Photo source: yale.com
The 90s were remembered for the start of the production of equipment with a built-in side shift device and various fixed carriages. load capacity warehouse equipment exceeded 5 tons. At the same time, a steering cylinder was built into the rear axle " double action"(or in other words - hydrostatic steering). Having changed the device, design and ergonomics, the forklift has practically not changed functionally. It has become more reliable, more productive and safer. It has become much easier to operate the equipment.
The device of a modern forklift
The device of a modern loader (Fig. a) is based on a pneumatic wheel undercarriage with dual drive wheels at the front (2) and steerable single wheels at the rear (6), allowing the machine to remain stable when moving and manoeuvring. Also, the forklift device includes a hydromechanical load lifter (3) with a replaceable working body (1) of a counterweight (5), an internal combustion engine (4), mechanical, hydromechanical or hydrostatic transmission, travel mechanism, forklift hydraulic system and control system.
Photo source: yale.com
The device of the main working body (forklift) is a pickup in the form of 2-3 bent at an angle of 90 degrees. steel bars that are placed under the load. The forklift is pivotally attached to the lifting carriage of the forklift. Based on how it's set up working equipment by car, there are front and side loaders. Frontal loaders move the load on fork lifts, side loaders - on the platform.
The main frame (9) of the forklift is pivotally fixed to the frame of the machine. A retractable frame (12) moves on the rollers inside the main frame. A cargo carriage (13), suspended on 2 cargo chains (7), moves along its guides on rollers. Work equipment (1) is attached to the carriage. The load chains go around the sprockets (8) on the retractable frame, are fixed on the main frame and create a double chain hoist - this allows you to increase the lifting speed.
There are several types of frames:
- 2-section frame with no free play - DLFL
- 2-section free-swing - DFFL
- 3-section free-swing - TFFL
A forklift can have a so-called wagon version - a folded frame no more than 2.2 m.
The forklift is powered by an internal combustion engine. It is worth noting that modern forklifts are equipped with different types of engines: gasoline, diesel, gas electric. But there are loaders with a so-called hybrid powertrain. For example, Still has released a hybrid engine that combines diesel and electric drives.
The bulk of forklift trucks are equipped with a hydromechanical transmission. The mechanical transmission on the machines is used to drive the drive axle and hydraulic pumps, the hydraulic transmission is used to drive the forklift and steering. Forklift trucks, which can lift heavier loads, use a pneumatic transmission to actuate the wheel brakes using energy compressed air. Basic equipment most mid-range models include a servo brake. Heavy-duty models are often equipped with oil-bath disc brake systems.
Photo source: yale.com
The installed hydraulic booster allows, with a slight pressure on the brake, to effectively control the speed of the loader.
The chassis design affects the stability and load capacity of the machine. The increased wheelbase, minimized wheel diameter and placed as low as possible the center of gravity of the lift truck - all this ensures constant contact of all wheels with the road.
According to European Union regulation EN1726, all lift trucks are tested for lateral and frontal stability. Therefore, forklifts that can lift massive loads have a rigid welded chassis in their device, and for an acceptable center of gravity, the engine, gearbox and differential are placed as low as possible.
Another important point is the tires for the forklift.
The forklift can be equipped with:
- Elastic and with a high level of stability wheels made of solid rubber - superelastic (SE). In the process of working on uneven surfaces, fairly rapid wear of the bridge parts is possible.
- Bandage wheels that have a low profile. The design of bandage tires provides for the presence of a thin shock-absorbing layer, which is demanding on the "evenness" and quality of the coating.
- Pneumatic wheels. Such wheels will not provide a sufficiently high load on the suspension when driving and working on rough roads.
The device of all modern forklift trucks provides for emergency warning light and sound signals with electronic devices displaying information about the limiting state of the controlled parameters of the motor and other systems.
Operator's workplace in a forklift
Modern forklifts are equipped with a large cab on shock absorbers. The cab is soundproofed and equipped with a FOPS and ROPS safety system. The forklift is controlled from the operator's seat, which is equipped with a soft adjustable seat with a back. The operator's seat is equipped with a seat belt that will restrain the driver during unplanned braking and if the lift truck overturns. The safety grid will protect against a possible fall of part of the load and will allow you to transport big loads without being in danger.
Photo source: yale.com
The operator's workplace in forklift trucks operating in open areas is located in a closed cab. In cold weather, it is heated. The open cab is protected from falling cargo by a slatted roof. The side racks provided in the forklift device will protect the driver from injury if the machine overturns.
TO Category:
Loaders
The device of universal forklifts
4013 and 4014 lift trucks
The machines in question have essentially the same constructive scheme with wheel formula 4X2 (Fig. 4.1). The chassis is a three-dimensional welded frame made of steel sheets and rolled elements and at the same time is the lining of the machine. Forklift support brackets are welded to the front beams of the frame, and a bumper is bolted to the rear, which also serves as a counterweight. Chassis contains a front axle with four driving wheels installed in pairs and a rear axle with two steered wheels. Two-frame forklift. The engine is located behind.
The cabin is welded, two-door, single, bolted to the frame at four points, mounted on rubber shock absorbers. The windshields and the rear window are equipped with electric wipers. The metal floor has hatches for access to the transmission. The driver's seat is shock-absorbed, it can be moved in the longitudinal direction and in height to the most comfortable position. To heat the cabin in cold weather, there is a type 015B heater that runs on the same fuel as the engine. The cabin is equipped with a fan. There is a rear-view mirror on the outside on the left. Both models of lift trucks can be supplied without a driver's seat guardrail cab.
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Forklift trucks vary overall dimensions and the following units: axles, front wheels with brakes and tires. The same are: engine, clutch, gearbox, reverse gear, cardan drive, hand brake, electrical equipment, hydraulic pump and tilt cylinders, hydraulic valve, gearbox for driving both hydraulic pumps, oil tank and fuel tank. On forklifts of model 4013 of the first releases, forklifts designed for model 4014 were installed. Forklifts of model 4013, released in 1977, have a hydraulic booster from a ZIL-130 car, and models 4014 have a hydraulic booster Lviv plant forklifts.
The engine is attached to the forklift frame at four points through rubber cushions. The engine cylinders are cast iron in one block with the crankcase. The aluminum alloy cylinder head is studded to the block through a steel-asbestos gasket. Lubrication from the gear pump is supplied under pressure to the main and connecting rod bearings of the crankshaft, bearings camshaft and the gears that make it spin. The rest of the moving parts in the crankcase are splash lubricated. The pressure reducing valve is located in the pump cover and protects the lubrication system from overload when starting a cold engine. The bypass valve is installed in the cover of the coarse filter and turns off the filter when the filter element is dirty (in this case, unfiltered oil enters the line). Safety valve is connected to the oil cooler pipeline and stops the circulation of oil in the system at a pressure of less than 100 kPa (1 kg / cm2).
Engine crankcase ventilation is forced due to the vacuum created in the air cleaner and crankcase.
The undercarriage transmission of the 4013 and 4014 lift trucks uses off-the-shelf automotive units, as well as a specially designed reverse gear. It is assembled in a separate crankcase. The change in the direction of movement of the forklift is made from the driver's cab by a lever pivotally connected to the rod, on which the fork is fixed to move the driven shaft gear. To enable reversing the gear is engaged with the intermediate gear, which is constantly rotated by the gear of the drive spline shaft. The intermediate gear rotates on a roller bearing mounted on a fixed axle. The flange, which rotates with the drive shaft, is used to transmit torque from the gearbox output shaft.
The forward or reverse gear engagement lever is located under the steering wheel and must always be in one of the extreme positions when the lift truck is parked. The central hand brake is located between the gearbox and the reverse gear.
Rice. 4.1. Forklift 4014
The drive axle housing of the 4013 lift truck is a stamped steel beam welded in two pieces. Inside the beam are the main gear of the hypoid type with a gear ratio of 6.83 (with one pair of bevel gears), differential and axle shafts. The torque from the reverse gear is transmitted to the main gear by a cardan shaft with two hinges on needle bearings. The wheels are attached to the hubs by means of studs (Fig. 4.2).
The 4014 forklift drive axle has a final drive consisting of a pair of helical bevel gears and a pair of spur gears with helical teeth, differential and axle shafts. The driving bevel gear is made integral with the splined shaft, on which the flange is fixed for connection with cardan transmission. The driven bevel gear is pressed onto the shaft flange and connected to it with rivets. The split differential box consists of two parts. The driven spur gear of the main gear is rigidly connected to it.
In the differential box, two bevel gears of the axle shafts and a cross with four satellites are mounted. The box rotates on two tapered roller bearings mounted in split bearings with covers machined together with the final drive housing.
The main drive spur gear is made integral with its shaft, the tapered roller bearings of which are installed in the crankcase covers.
The design of the hubs and fastening of the drive wheels is the same as that of the 4013 forklift.
Rice. 4.2. 4013 forklift drive wheel hub and its mounting:
1 - axle shaft; 2 - hub; 3 - bolt-puller; 4 - axle shaft fastening stud; 5 - wheel stud; 6 - brake drum; 7 - brake disc; 8 - axle housing
The steering contains a hydraulic booster and is similar for both models of forklifts (Fig. 4.3, a). The globoidal worm of the steering mechanism is pressed onto the lower end of the steering shaft, it is supported by two roller bearings (Fig. 4.3, b). The three-ridged roller coupled with the worm is fixed in the fork of the bipod shaft, the roller rotates on two needle bearings. The rotation of the worm causes the roller and bipod shaft to rotate, the bipod rod to move and the hydraulic booster to actuate. The latter is connected by the end of the piston rod through a ball joint to a console mounted on the chassis of a forklift (Fig. 4.4). The hydraulic booster contains an executive cylinder and control device golden type. When oil is injected to the left or right of the piston, the corresponding movement of the cylinder relative to the piston occurs. On the opposite side of the rod in the cylinder body there is a spool sleeve with through slots connected by annular grooves in the body. A round spool is placed inside the sleeve. It can move along the sleeve in both directions by 2.5 mm from the middle neutral position, in which it is installed under the action of a spring. The spool is connected by a rod, a spring and two crackers with a ball pin of the steering arm rod.
As long as no force is applied to the steering wheel by the driver, the spool is in the neutral position, and the sections of the four annular slots formed by the edges of the spool and sleeve are equal. In this position, the oil pumped by the hydraulic booster pump passes through the slots bounded by the inner edges of the slots bounded by the outer edges of the spool, into the drain spool, to both cavities of the slave cylinder and through the pipe. The pressure in both cavities of the cylinder is equal to the pressure in the drain pipe. When the driver rotates the steering wheel, the bipod rod moves the spool, while the cross sections of one pair of the above slots increase, and the other pair decreases. One cavity of the slave cylinder is connected to the line high pressure, and the other - with a drain. On one side of the piston, the pressure increases and the body of the slave cylinder moves in the same direction until the sections of all slots between the edges of the spool and sleeve become the same and the spool returns to the neutral position. This will happen when the driver stops turning the steering wheel. The movement of the cylinder body is accompanied by the same movement of the rod connecting the hydraulic booster with the intermediate lever.
If the power steering system is damaged or the lift truck is towed with another machine with the engine off, it is possible to operate without power steering. In this case, both cavities of the slave cylinder communicate with each other through an emergency ball valve.
The manual central brake of the GAZ-51A model contains a drum screwed to the flange of the output shaft of the gearbox, two inner shoes and a drive device consisting of a handle and two rods with a rocker between them.
On the forklifts under consideration, as a rule, hydraulic boosters, pumps for them and central hand brakes from the ZIL-130 car should be installed.
The steering mechanism, combined with the hydraulic booster, consists of a crankcase, a screw coupled with a nut by means of balls, gear rack, rigidly connected to the nut and which is the piston of the hydraulic booster, and the steering arm shaft with a gear sector (Fig. 4.5). The steering gear housing serves as a hydraulic booster cylinder.
Rice. 4.5 Steering gear and hydraulic booster unit for lift trucks 4013 and 4022 (with hydraulic pump NSh-32U steering booster)
The piston-rack is constantly engaged with the gear sector. Oil from an independent pump is supplied to the body of the hydraulic booster control valve. Through the second hole in the housing, the oil is led back to the pump through the low pressure hose. The valve body is located between the top and intermediate covers. Inside it is placed a spool fixed on the screw shank between thrust ball bearings with a nut. The spool and screw can move in both directions from the middle position by 1 mm, to which they are returned by springs and plungers, which are under pressure from the oil pumped by the pump. When the steering wheel is turned, the steering arm and the gear sector on its shaft are rotated, which is accompanied by the movement of the screw along with the spool. The latter opens access to one of the cavities of the hydraulic booster cylinder to oil from the discharge line and connects the other cavity to the drain line. The piston under oil pressure moves with considerable effort in the same direction as the force transmitted by the gear sector.
The hydraulic booster contains check valve built into the control valve body. The safety valve is installed in the pump housing. A plug with a magnet is provided in the crankcase of the steering mechanism to trap particles of steel and cast iron from working fluid.
The normal operation of the screw-nut pair is ensured when the axial movement of the bipod shaft relative to the end of the adjusting screw is not more than 0.06 mm.
The power steering hydraulic system has an independent working fluid reservoir mounted on the pump housing.
Both models of lift trucks have drum-type foot brakes built into the front drive wheels. The drive is hydraulic; inside brake drum Each wheel is equipped with: an actuating hydraulic cylinder, two pressure pads, a brake spring (retracting the pads). The brake systems of the 4013 and 4014 lift trucks differ in that the former does not have a device for automatically stabilizing the gap between the pads and drums.
To the executive wheel hydraulic cylinders, brake fluid is supplied from the main brake cylinder when the driver presses the pedal (Fig. 4.6): the pusher moves the piston to the right, the cuff closes the compensation hole B, the pressure in the working cavity G of the cylinder increases and the exhaust valve opens. As a result of this, wheel hydraulic cylinders are activated, braking is performed. After releasing the brake pedal, the spring moves the piston to the left, the pressure in the working cavity of the master cylinder decreases, brake pads and the pistons of the wheel cylinders under the action of the retracting springs return to their original position. In this case, the brake fluid is displaced from the wheel cylinders into the main through inlet valve.
The foot brake device of the model 4013 forklift truck is shown in fig. 4.7. The brake support shield is bolted to the axle housing flange, the brake drum is bolted to the hub flange on the side of the inner drive wheel. At the bottom, two fingers are screwed to the shield, which serve as supports for brake shoes with linings, the upper ends of which are pulled together by a spring and pressed against the pistons of the wheel brake cylinder. The spring holds the pads in the unbraked position. When the driver presses the pedal, the brake fluid from the master cylinder enters the wheel cylinders, their pistons diverge, overcoming the force of the spring, and the pads are pressed against the brake drum.
The position of the shoes relative to the drum is adjusted by turning the eccentrics mounted on bolts with shock-absorbing springs. For the same purpose, eccentrics of the support pins of the pads are provided.
The wheel hydraulic cylinder is connected to the main brake cylinder by a tube.
Rice. 4.6. Hydraulic foot brake master cylinder:
1 - filler cap; 2 - reflector; 3 - filter mesh; 4 - gasket; 5 - cover; 6 - cylinder body; 7 - return spring; 8 - inner cuff of the piston; 9 - piston; 10 - outer cuff of the piston; 11 - pusher; 12 - rubber cap; 13 - thrust; 14 - pedal; 15 - inlet valve; 16 - exhaust valve spring; 17 - thrust spring plate; 18 - exhaust valve; A - non-working cavity of the cylinder; B - bypass hole; B - compensation hole; G - working cavity of the cylinder
Rice. 4.7. Model 4013 Forklift Foot Brake
The hand brake from the ZIL-130 car has a drum attached with screws to a flange mounted on the splined end of the driven (secondary) shaft MOX 11 and also designed to secure the driveline hinge to the front axle of the loader (Fig. 4.8). When braking, two brake pads are pressed against the inner surface of the drum, actuated by a lever by means of rods connected by a toggle lever.
The hand brake is adjusted by reducing the gaps between the pads and the drum, which have increased due to the wear of the linings (detected by an increase in the free play of the lever /), in the following sequence. The MOX lever is set to the neutral position. The rod is disconnected from the lever, after which it is transferred to the extreme forward position. The length of the rod is changed by screwing the fork 6 onto it so that the loader is braked completely when the pawl is moved using the rod for 4-6 teeth of the sector fixed on the frame of the machine. In the case of transferring the lever to the extreme forward position, the brake drum must rotate freely without touching the shoes. If braking is not achieved at the minimum length of the rod, it is necessary to move the fastening pin of the end of the rod into the next hole of the adjusting lever and re-set the desired length of the rod, fixing it with a nut. At the end of the brake adjustment, the rod mounting pin on the lever must also be securely fastened with a nut and cotter pin.
The 4013 and 4014 lift trucks have different lift/lower cylinders and are otherwise identical in design. The outer frame is welded, the racks are made of rolled channels. A lifting-lowering hydraulic cylinder is fixed on the base plate of the lower transverse connection. Outside, trunnions are welded to the racks for articulated fastening of the forklift to the chassis of the machine. Above are two brackets pinned to the tilt cylinder rods. At the top of the racks there are two rollers that guide the movement of the inner frame. It is also welded, with I-section struts connected by three cross braces. Two vertical guide corners are welded to the top of them. Two rollers of a traverse mounted on the top of the plunger roll along them. When moving these rollers within the guide corners, a “free” lift of the carriage is performed. In the lower part of the racks, two rollers are installed on the axles welded to them, moving along the shelves of the racks of the outer frame. Side rollers are mounted at the ends of the axles.
The carriage is suspended on two plate chains, enveloping the blocks on the traverse of the lift cylinder plunger and fixed at one end on a bracket welded to the cylinder, and at the other end on the carriage. The carriage consists of upper and lower plates connected by racks. Four rollers are installed on them, which roll along the shelves of the racks of the internal frame of the forklift, and four rollers that roll along the walls of these racks and serve to transfer transverse loads to them (Fig. 4.9). The chains have a screw stretching device. The axles of the rollers are mounted in the axles of the rollers of the carriage indicated above. The thrust washers of the latter are fixed with screws.
The axles of the side rollers have eccentric square trunnions. Therefore, to adjust the backlash, the axle must be rotated 90 or 180°. Since 1975, instead of skating rink 5 on tapered bearings a special roller - bearing is installed.
Rice. 4.8. Hand brake drive
Rice. 4.9. Carriage
Rice. 4.10. Hydraulic System Diagram:
1 - three-spool distributor; 2 - hydraulic booster valve block; 3 - power steering; 4 - pressure gauge; 5-pump of the hydraulic booster system; 6- oil tank; 7 and 8 - locking devices; 9 - pump of the forklift system; 10 - lifting-lowering cylinder; 11 - valve block forklift; 12 - filter in the drain line; 13 - tilt cylinders; 14 - swivel couplings for connecting hoses of replaceable working bodies; 15 - pressure valve
The diagram of the hydraulic system of forklift models 4013 and 4014 is shown in fig. 4.10. The oil tank is common to the hydraulic systems of the forklift and power steering, the hydraulic pumps of which operate continuously during the operation of the loader engine. Depending on the position of the hydraulic distributor spools, oil is supplied either to the corresponding cavities of the working cylinders or is returned to the tank. The forklift valve block consists of a check valve and a fluid flow regulator, designed to securely hold the lifted load. In the event of a hose break, it is necessary to break the seal and unscrew the valve, the load is lowered only with manual control. When lifting the load, the working fluid under pressure presses the check valve from its seat and enters the lifting-lowering cylinder. When the valve spool that controls this cylinder is in the lowering position, the working fluid is supplied at a command pressure of the order of 1600-1800 kPa (16-18 kg / cm2) to the fluid flow regulator. The latter gives a greater or lesser outlet of liquid into the drain pipe, depending on the magnitude of the command pressure, in accordance with this, the speed of lowering the load will be increased or decreased.
The valve of the power steering system protects against overload in case of pressure increase. The device of the valve block used when installing the ZIL-130 hydraulic booster is shown in fig. 4.11. The safety valve is placed inside the bypass valve and opens at a pressure of 0.65-10.4-0.7-104 kPa (65-70 kg/cm2). Bypass valve 2 is included in the discharge pipeline A from the pump to the hydraulic booster through a damper. Pipeline B to the hydraulic booster is connected to. pipeline A channel B in the block body. The cross section of channel B is adjusted by a screw for an oil flow rate of 13 l/min. An increase in the oil supply by the pump is accompanied by an increase in the pressure difference in the cavities connected to pipelines A and B, including at the ends of the bypass valve. As a result of this, it will move to the right, compressing the spring holding it (not shown in the figure), will open access from the discharge pipeline A to the drain G, and subsequently the amount of oil supplied to the hydraulic booster will almost stabilize.
The oil tank has two filters: in filler neck and, next to it, in the drain line from the hydraulic distributor (Fig. 4.12). In the filter housing under the inlet A is installed bypass valve, through which the working fluid can enter the tank without filtration in case of clogging of the filter elements, in order to prevent their damage when the pressure in cavity B increases due to an increase in filtration resistance. The valve is adjusted to a pressure of 400-450 kPa (4-4.5 kg/cm2). Normally, the working fluid from cavity B passes through the filter elements and slots C in the central tube and outlet fitting and then into the oil tank.
Rice. 4.11. Hydraulic booster valve block ZIL-130
The drive of both hydraulic pumps is common, it consists of a cardan drive from the toe of the engine crankshaft and a reduction gear with a gear ratio of 1.65. The gearbox is single-stage with cylindrical helical gears operating in an oil bath.
The secondary shaft of the gearbox has internal splines, and, since the diameters of the hydraulic pump shafts are different, it is supplemented with an adapter, into the spline hole of which the power steering hydraulic pump shaft is inserted.
Three-spool hydraulic distributor with a one-piece cast body. Each spool section has two outlets. The spools are returned from the working position to the neutral position by springs. If all spools are in the neutral position, the working fluid from the internal cavity of the pressure section enters the drain channels of the working (spool) sections and then through the cavity of the drain cover to the oil tank. Safety and non-return valves are built into the pressure section. The latter eliminates the counterflow of the working fluid from the hydraulic cylinders through the pressure section and overflow channels during the switching on and off of the spools.
The command pressure to open the working fluid flow regulator for lowering the load (or gripping body) is supplied by a throttle. In this case, oil is supplied to the valve block mounted on the lift cylinder, as a result of which oil will be supplied to the drain line.
Rice. 4.12. Drain filter:
1 - body; 2 - cover; 3 - retaining ring; 4 - spring; 5 - cap; 6 - valve ball; 7 - valve body; 8 - spring; 9 - supporting bracket; 10 - central tube; 11 - filter element; 12 - outlet pipe
Rice. 4.13. The valve block of the lifting-lowering cylinder: - housing; 2 - flow control valve when lowering the load; 3 - spring; 4 10 - fittings; 5 - check valve; 6 - retracting device; 7 - spring; 8 - locknut; 9 - cap
When lifting the load, oil is supplied through the fitting to the end of the check valve, presses it to the left and enters the cylinder through the cavity (Fig. 4.13). The valve that regulates the oil flow is pressed against the seat by its pressure and spring force, that is, it is locked. If the spool of the hydraulic distributor that controls the lifting cylinder is in the neutral position, then the oil pressure in the cylinder from the action of gravity on the load and the parts of the forklift that are on the weight and the force of the spring close the check valve. The flow control valve also remains closed. When the hydraulic distributor spool is set to the “Lowering” position, oil from it is supplied through the fitting to cavity A and moves the valve to the right, opening it. In this case, the oil displaced from the lifting-lowering cylinder goes to the drain.
If the forklift engine fails when the load is raised, to lower it, it is necessary to: set the hydraulic distributor spool to the neutral position, break the seal and unscrew the retracting device by 2-3 turns so that the load moves smoothly to the lower position.
The electrical circuit of forklifts of models 4013 and 4014 is single-wire (the negative is connected to ground), in principle the same as that of model 4043M (Fig. 4.14).
Rice. 4.14. Scheme of electrical equipment for lift trucks models 4043M and 4045N: 1 - spark plug; 2 and 3 - resistance to cancel interference; 4 - distributor; 5 - starter; 6 - battery; 7 - water temperature sensor; 8 - oil pressure sensor; 9 - rear lamp with lamps of clearance and signal "Stop"; 10 and 15 - switches of signals "Stop" and sound; 11 - ignition switch; 12 - gasoline level sensor; 13 - instrument cluster; 14 - light switch; 16 - sound signal; 17 - turning headlight; 18 - fuse box; 19 - portable lamp; 20 - relay-regulator; 21 - generator; 22 - ignition coil
Forklift models 4043M and 4045P
The design schemes of the considered forklifts and models 4013 and 4014 are similar.
The frame of the forklift is welded from standard rolled steel. In the rear part of the frame, on rubber cushions, an engine with a clutch and a gearbox (KP) assembly is installed. The torque from the gearbox is transmitted by the cardan shaft to the reverse gear (MOX), which is also a reduction gear. MOX is connected by a second cardan shaft to a drive axle rigidly fixed in front of the frame.
Units and assemblies of 4043M and 4045R forklift trucks are unified by about 60%. Their transmission is basically the same as that of the models discussed above. The drive axles of the 4043M and 4045R forklift trucks are borrowed respectively from the GAZ-52 and ZIL-130 vehicles.
The drive axle of the GAZ-52 model consists of a split crankcase, the main single-stage transmission with bevel gears with spiral teeth, a differential and two axle shafts. The adjustable stop of the driven gear of the final drive makes it possible to maintain an almost constant gap of about 0.25 mm between the ends of the gear and stop bushing.
The front and rear wheel hubs of the 4043M and 4045P lift trucks are mounted on two roller bearings.
The suspension of the rear steered wheels is balanced, oscillating around the longitudinal axis, which allows the forklift truck to overcome road roughness and provides the same load on the wheels. The rear axle beam can be rotated all the way into the rubber buffers fixed on the chassis plate. The wheels are connected to the beam by automotive-type swivel fists.
The steering is different from that shown in fig. 4.3, but by the absence of an intermediate lever and additional longitudinal rod.
hydraulic booster, oil pump and the steering mechanism, as well as the parking brake, are the same as those discussed above for the 4013 and 4014 lift trucks.
The lift trucks of the 4043M and 4045P models do not fundamentally differ in design from those used on the 4013 and 4014 models.
Their hydraulic system does not contain a valve block of the lifting cylinder and a pressure valve associated with it.
To reduce the speed of the load when lowering, a single-acting throttling valve has been introduced into the line connecting the lifting cylinder with the hydraulic distributor, which serves as a lowering speed limiter. When lifting the load, the working fluid pumped by the pump presses the valve from its seat and gains free access to the cylinder cavity. To prevent leakage of fluid from the oil tank when the hydraulic system hoses are broken or disconnected, the suction and drain pipes are siphon and break the fluid jets by communicating the pipes at the bend at the top with the surrounding atmosphere. In the drain tube, the jet breaks automatically, for which it has two holes, in the suction tube - by manually opening the liquid jet break valve connected by a hose to the suction siphon tube in the oil tank.
Electrical equipment includes energy sources (starter acid battery, generator), consumers (engine ignition system, lighting, sound signal, various sensors), switches, etc. Maximum current generator 20 A. The generator is driven V-belt drive. Battery ignition system, consists of a distributor, an ignition coil, glow plugs, a switch with a lock, resistances to suppress radio interference. The starter is activated by a lever through a freewheel, which prevents the starter from excessive speed increase after the engine starts. The starter should turn on for no more than 10-15 s. The fuses are rated up to 10 A. They are located under the instrument panel.
Automatic switching on of the generator under load and switching off (when the engine speed is reduced) with alternating charging and discharging, respectively battery carried out by a relay controller. Its purpose is also to protect the generator from overload and to maintain the voltage within the specified limits for the normal operation of all electrical appliances. The relay-regulator has mounted on common panel relay reverse current, current limiter and generator voltage regulator. The reverse current relay turns off the generator when the voltage drops below the established norm.
4046M, 4016 and 4055M lift trucks
Forklifts model 4046M provide loading of UUK-2.5 (3) containers with a gross weight of up to 2.5 tons on one side of the track with installation on cars both in the first and second rows and UUK-5 containers with a gross weight of up to 3.5 tons (placed in one row with a width along the length of the car), and models 4016 under the same conditions containers UUK-2.5 (3) and UUK-5 with a gross weight of up to 3 and 4 tons, respectively.
The 4046M and 4016 machines under consideration (Fig. 4.15) are based on the 4045M and 4014 forklifts, respectively. They allow you to move the same load as the base models, lifted at a longer reach of the boom hook. In this regard, their length, base and dead weight are correspondingly increased.
The structure of the forklift frame and the lifting-lowering cylinder is similar to that used on the base model 4045M, but their height is somewhat higher. The main working body of the forklift is a cantilever boom with a variable reach hook, on which are hung flexible slings with four branches with pull hooks at the ends. The hook with and without a load is moved by an articulated lever mechanism along the boom using a hydraulic piston cylinder double-acting, hinged on the boom; piston diameter 120 mm, stroke 340 mm. Instead of an arrow, a fork or bucket can be mounted on the carriage, supplied for a fee.
Rice. 4.15. 4016 Forklift
Forklift model 4055M is designed for installation on AN-10 and IL-18 aircraft and removal of aircraft engines from them. It is a modification of the 4045M forklift and differs mainly in the technical characteristics, the design of the forklift and the hydraulic distributor. It is equipped with a cantilever variable reach boom. The three-frame forklift contains the following main parts: outer, intermediate and inner frames, lifting cylinder, carriage with a cylinder of transverse movement, suspension chains of the intermediate frame and carriage. The outer frame is hinged to the chassis, the intermediate frame moves along the racks of the outer frame, and the inner frame moves along the racks of the intermediate frame. To reduce resistance and wear of the forklift frames and the carriage, they are equipped with rollers on cylindrical roller bearings.
Rice. 4.16. Hook Travel Cylinder:
1 - flange; 2 - sector persistent; 3 - cylinder cover; 4 - body; 5 - stock; 6 - piston; 7 - thrust ring; 8 - cuff; 9 - wiper ring
Rice. 4.17. Diagram of the hydraulic system of the model 4055M forklift:
1, 2 - cylinders for moving the hook, lifting-lowering and tilting; 4 - power steering pump; 5 - oil tank; 6 - valve for breaking the liquid jet in the suction line; 7 - filling filter; 8 - drain filter; 9 - pump of the forklift system; 10 - pressure gauge; 11 - stopcock; 12 - bypass valve; 13 - safety valve; 14 - hydraulic distributor; 15 - emergency valve; 16 - pressure reducing valve; 17 - hydraulic booster; 18 - cylinder of transverse displacement of the boom along the carriage; 19
The lifting cylinder is fixed on the lower part of the intermediate frame, the plunger - on the upper transverse link of the inner frame. It has two rollers. They are enveloped by lamellar chains, fixed at the ends at the top of the intermediate frame and on the carriage. Two of the same rollers are attached at the bottom of the intermediate frame. They are bent from below by two lamellar chains, which are fixed at the top - on the outer frame and at the bottom - on the inner frame. The tension of both pairs of chains is regulated by independent screw devices. Racks of all three frames are welded I-section.
Single acting lift cylinder, plunger diameter 190 mm, stroke 2350 mm. Cylinder for moving the hook along the boom of a double-acting piston type, cylinder diameter 120 mm, piston stroke 340 mm (Fig. 4.16). The cylinder of the transverse displacement of the boom on the carriage is double-acting piston, cylinder diameter 120 mm, piston stroke 400 mm. Tilt cylinders as for 4045H lift truck.
The boom differs from the one used on the 4046M model by the upper supporting strut (instead of the strut from below) and the absence of a stand. Mounting on the carriage is made using the L-shaped hook on top. The lever-hinge mechanism for moving the hook is similar to that used on the 4046M model.
The diagram of the hydraulic system of the forklift and power steering drives is shown in fig. 4.17. Oil is supplied by pump 9 to the inlet (pressure) cover of the four-section spool-type hydraulic distributor. Depending on the position of the spools, oil enters the working cavities of the respective cylinders. The tilt cylinder control spool is shown in the diagram in the tilt back position, the rest of the spools are in the neutral position. The used oil, as well as the oil coming through the bypass valve 12 when the spools are in the neutral position, from the outlet cover of the hydraulic distributor is fed through the drain pipeline back to the tank.
Rice. 4.18. 4055M Forklift Forklift Valve Block:
1 - body; 2 - valve seat; 3 - bypass valve; 4 - spring; 5 - bypass valve guide; 6, 7, 9 - sealing rings; 8 - persistent cap; 10 - safety valve seat; 11 - ball valve; 12 - safety valve guide; 13 - safety valve spring; 14 - safety valve adjustment screw; 15 - cap
The bypass and safety valves of the forklift system are combined into a block (Fig. 4.18). Oil from the discharge line in front of the hydraulic distributor enters the body of the block, through hole A passes into cavity B, then through the calibrated hole C in the annular belt of the bypass valve into cavity D and through channels D and E to the ball of the safety valve.
When maintaining normal pressure in the system, the bypass valve is pressed against its seat by the force of the spring. In the event of a sharp increase in pressure in cavity B, the force on the valve collar on the opposite side of hole C, due to the smaller area of \u200b\u200bthe belt on this side and the resistance created by this hole, will be lower and the valve will move away from the seat, connecting cavity B with drain line C. If the bypass valve does not work, then with a further increase in pressure in the system to the value to which the safety valve spring is adjusted, the latter will open and the oil will drain through channel E.
Model 4075 Forklift
The 4075 rough terrain forklift has two drive axles (Figure 4.19). If necessary, it is possible to turn on the front or rear axle or both axles together. The lift truck can work on uneven ground and overcome fords up to 1 m deep. It has significant ground clearance, and the rear roll angle is 60% larger compared to lift trucks with a single drive axle of the same capacity. The radius of the longitudinal patency is 1250 mm, i.e., almost 2 times less than that of conventional forklifts. The design of the movement mechanism of the model 4075 forklift truck is much more complicated: both drive axles contain differentials, there is additional device to turn on the rear axle. Engine power is 65% higher. Both axles have two running wheels and the same track, which helps to reduce the resistance to movement on soft soils. The rear wheels are steerable.
The torque from the engine through the clutch and gearbox through the cardan shaft is reported to the transfer case, which also serves as a reverse mechanism. Two cardan shaft connect transfer case with front and rear drive axles. Of these, the front one is rigidly fixed to the chassis, and the rear (controlled) is balanced and can swing about the longitudinal axis.
The steering has a hydraulic booster. Front and rear wheels equipped with pneumatically actuated drum brakes.
Rice. 4.19. 4075 Rough Terrain Loader with Grab Bucket
The forklift is unified with the forklift 4014. The hydraulic system differs from that adopted on the latter by the pump and the presence of an adjustable throttle installed in the cab and used to change the speed of the load during lifting and lowering from 0 to maximum. Double cab with heater and fan, shock-absorbing, adjustable seat, like on a 4014 forklift.
On the 4075 forklift, it is possible to use: fork pickups and a bulldozer-grab grab and a blockless boom.
The forklift, forks and hydraulic system units are used from the model 4014 forklift. The model 4075 forklift is recommended for mass production.
Model 4022 Forklift
The forklift is unsprung, has the usual layout: a box-shaped chassis welded from sheet metal, four driving front wheels grouped in pairs, two rear steered, a two-frame forklift is located in front, the engine is behind, there is no cab; the driver's seat is protected by a fence (Fig. 4.20).
The running gear transmission contains: a clutch, a cardan gear and gear change and reverse gear mechanisms aggregated into one combined gearbox, a main gear and a differential. Such constructive solution associated with the small size of the machine. The clutch shaft rotates in single-row ball bearings, one of which is installed in the engine flywheel, and the other in a bracket seat bolted to the clutch housing and chassis cross member. The driven disk moves (by pressing the control pedal and releasing it) along the front splined end of the mentioned shaft. It is connected by a cardan transmission by means of flanges to the input shaft of the gear change mechanism (KP). The clutch assembly is controlled by a hydraulic drive from the Volga car (Fig. 4.21). The pedal is attached to the chassis with the help of a bracket and is connected by an eccentric axle and a pusher to the piston of the main drive cylinder. The latter is made in a common cast-iron housing with the main brake cylinder and has a reservoir in common with it, into which brake fluid is poured. The cylinder body is bolted to the bracket. Inside the clutch master cylinder is a spring that returns the piston to its original position. The slave cylinder is bolted to the clutch housing. The retractable spring 8 returns the fork 10 and the rod 9 when the pedal is released.
Adjustment data:
1) the gap between the pusher and the piston of the clutch master cylinder is 0.5-1 mm;
2) travel of the end of the fork from a stop against the rod to a position in which the clutch release clutch reaches the stop against the heads of the pressure plate levers, about 4.5 mm;
3) total free play clutch pedals 35-46 mm;
4) the brake fluid level in the master cylinder reservoir is 12-15 mm below the top of the filler hole.
Rice. 4.20. Model 4022 Forklift
main gear two-stage, with one pair of cylindrical and one pair of bevel gears. The driven bevel gear 4 is rigidly connected to the differential cross, on which the satellites are installed. The gears of the differential axle shafts have slotted holes into which the splined ends of the axle shafts are inserted.
Rice. 4.21. Model 4022 Forklift Clutch Control Actuator
1 - pedal; 2 - spring returning the pedal; 3 - bracket; 4 - master cylinder 5 - connecting hose; 6 - bypass valve; 7 - executive cylinder; 8 - from the pull spring; 9 - stock; 10 - fork for moving the driven clutch disc;
The axle shafts are fully unloaded (from bending moments), forged integrally with the outer flanges. The hubs of the running wheels with brake drums are attached to the latter. The hubs are mounted on tapered roller bearings at the ends of the casings.
Foot and hand brakes shoe, acting on the front drive wheels. The brake drives are autonomous: foot-hydraulic, borrowed from the Volga car (Fig. 4.23), manual - mechanical. The piston pusher of the master cylinder of the brake is connected by an eccentric axis to the pedal lever, which ensures the straightness of the pusher movement when the latter is turned. AA couplings 9 with bypass valves are attached to the front chassis sheet. The valves are connected to the wheel brake actuators, the arrangement of which is similar to that shown in fig. 4.7. The gap between the pusher and the brake master cylinder piston is 1.2-2 mm.
Rice. 4.22. Combined front drive axle gearbox:
9 - casing of semiaxes; 2 - stuffing box; 3, 8, 16, 41 and 42 - gaskets; 4 - driven bevel gear of the main gear; 5 - crankcase; 6 - axle gear; 7 and 40 - traffic jams; 10 and 36 - bushings; 11 - needle bearing; 12 - axis; 13 - axle lock bar; 14. 21, 28 - thrust washers; /5 - drive gear of the first gear; 17 - cover; 18 - first gear and reverse carriage; 19 - first gear shift fork; 20. 23- switching clutches; 22 - second gear drive gear; 24 - fork of the second and third gears; 26 - carriage; 26 - third gear drive gear; 27 - input shaft; 29 - flange; 30 - reverse gear; 31 - crankcase cover; 32 - adjusting ring; 33 - nut; 34 secondary shaft gearbox; 35 and 39 - MOX driven gears; 37 - MOX shaft; 38- switch fork MOX; 43 and 44 - cylindrical gears of the main gear; “- bearing glass; 46 - shims; 47 - oil scraper ring; 49 - main gear bevel gear; 50 - differential satellite
Rice. 4.23. Foot brake drive:
1 - pedal lever; 2 - roller; 3 - withdrawal spring; 4-main brake cylinder; 5 - pusher; 6 - bushing; 7 - eccentric axis; 8 - bypass valve; 9 - clutch
The hand brake drive consists of a lever, a rod, a rocker-equalizer with retractable springs and two cables acting on the brakes of the right and left wheels.
The suspension of the rear steered wheels is made with the help of stepladders, with which the shaft is rigidly attached to the chassis (Fig. 4.24). The shaft is placed in the bushings of the axle bracket, as a result of which it, together with the running wheels, can tilt in both directions from the middle position in the transverse vertical plane. Grease is supplied to the bushings through grease fittings. In the middle of the axle beam on two tapered roller bearings there is a roller of the lever of the longitudinal steering rod. The steering trapezoid lever is connected to the splined roller. The latter is connected by transverse rods to the steering knuckle levers. Tie rods to adjust their working length, they have tips screwed onto the thread at the ends. At the ends of the rear axle beam, steering knuckles are mounted on pivots (from the GAZ-51 car). The beam rests on them through ball bearings. Axial play knuckle removed with shims. The vertical axial gap between the ends of the fists and the edges of the axle beams is not more than 0.15 mm. The pivots are fixed with pins and closed with plugs. Solid oil for lubricating the pivots is introduced into their internal channels through the side grease fittings (not shown in Fig. 4.24). On the pivots of the steering knuckles, the hubs of the rear running wheels rotate on tapered roller bearings. The bearings are closed on the outside with caps, and on the inside they are sealed with glands.
The steering mechanism and hydraulic booster are combined in one unit, installed under the control post on the chassis and connected to the column shaft with a swivel coupling (see Fig. 4.5).
Rice. 4.24. Model 4022 Rear Wheel Suspension
The forklift of the model 4022 auto-loader is two-frame. Its design is similar to that used on forklifts 4013, 4014, etc. The main difference is that the carriage is suspended on one lamellar chain and the hydraulic system is not connected to the power steering hydraulic drive. The lifting cylinder is mounted on the base of the outer frame on a support with spherical surface and secured with bolts using spring shock absorbers.
The hydraulic distributor (R75-PG1) is three-spool, made in one housing with bypass and safety valves, differs from the standard one in that the floating position of the spools is excluded in it. Throttling valves are included in the pipelines connecting the hydraulic distributor with the lifting-lowering cylinder and with the rod cavities of the tilt cylinders, which limit the flow of the working fluid going to the drain. The lift cylinder does not have a hydraulic lock.
4008 and 4028 lift trucks
The forklifts under consideration differ structurally from other universal forklifts mainly in the location of the tilt cylinders above the cab and the articulated installation of the boom on the carriage (Fig. 4.25). Otherwise, the kinematic scheme is the same as for the 4045P and 4014 forklifts.
On forklifts 4008, the same as on forklifts with a carrying capacity of 3-5 tons, the steering gear, power steering, hydraulic distributor, hydraulic pump of the forklift are used. The remaining units and structural elements are significantly different.
Forklifts have the following working bodies: fork pickup with a useful length of 1.5 m, for piece cargo weighing up to 10 tons; a boom that makes it possible to load onto gondola cars and platforms and unload containers and other cargo weighing up to 5 tons from them; hydraulically driven tongs for timber; grab for bulk, including lumpy, cargo. The basis of the grab is a tong grip, in the jaws of which two bucket-shaped shells are inserted. Only the 1.5 m long forks are the working attachment supplied with the forklift. Other interchangeable attachments must be specified in the order. Spar-type forklift frame. The engine is attached to it at three points.
The main control data for maintaining the ZIL-157K engine (forklift 4008) in good condition are as follows. The clearance between the cylinder and the piston skirt is 0.08-0.1 mm. Clearances in the locks of the piston rings: upper compression 0.25-0.6 mm, middle and lower compression 0.25-0.45 mm, oil-removable ring 0.15-0.45 mm. Pistons and piston rings for repair are supplied in three sizes, corresponding to an increase in their diameter compared to the original by 0.5, 1 and 1.5 mm, piston pins - in two sizes, respectively, to an increase in diameter by 0.12 and 0.2 mm, crankshaft bearing shells shaft - seven sizes, respectively, a decrease in the diameter of the necks of the shaft by 0.05; 0.3; 0.6; 1; 1.25; 1.5 and 2 mm. The engine lubrication scheme is shown in fig. 4.26. Oil under pressure is supplied to the camshaft bearings, main and connecting rod bearings of the crankshaft, the intermediate shaft of the distributor drive and the gears of the distribution mechanism, and by spraying and gravity flow to the cylinders, piston pins, camshaft cams, tappets, valve stems. For other engine data see chap. III.
The clutch unit is placed in a cast-iron crankcase. The clutch cover is bolted to the engine flywheel. Between the casing and the clutch pressure plate there are 16 springs that communicate pressure on the disc through rings made of heat-insulating material. The torque from the clutch casing to the driven disc with friction linings is transmitted through the pressure plate by four pairs of spring plates, which are fastened on one side to the casing, on the other - with bolts using bushings to the pressure plate. The clutch is disengaged by four levers connected by fingers to the pressure plate and other fingers to the adjusting fork. To facilitate the rotation of the levers, needle rollers are installed on the fingers. The clutch release clutch contains a release bearing. The clutch is acted upon by a fork connected by a rod to the clutch pedal. When the pedal is released, the clutch is returned by a return spring. The clutch disc has a friction-type torsional vibration damper.
The input shaft of the ZIL-157K (KP) gearbox is installed coaxially crankshaft and rests on it with its front bearing.
Rice. 4.25. Model 4028 Forklift
Rice. 4.26. Lubrication scheme for the ZIL-157K engine:
1 - oil gear pump; 2 - pressure reducing valve; 3 - valve for turning on the oil cooler; 4- oil radiator; 5, 6, 10 and 11 - channels for supplying lubricant, respectively, to the timing gears, the camshaft thrust flange, the ignition distributor drive shaft and the pusher; 7 - main highway; 8 - coarse filter (with a handle); 9-filter fine cleaning; 12 - bypass valve; 13 - oil receiver; 14 - drain plug
The gearbox is attached to the clutch housing on four studs screwed into it. Centering of the gearbox is carried out along the flange of the bearing cap input shaft. Gearbox bearings do not require adjustment in operation.
The drive axle is rigidly attached with four bolts on each side to cast steel brackets welded to the front ends of the frame side members. The final drive housing is bolted to the front drive gear. bridge over the differential (Fig. 4.27). A flange is fixed on the outer splined end of the input shaft for connecting to the driveline from MOX. Said shaft is made integral with the drive bevel gear. The driven bevel gear is attached to the flange of the output shaft, which is integral with the driving spur gear. The driven spur gear is rigidly connected to the split differential cross. The final drive shafts rotate each in two roller bearings. The differential consists of a split box with two bevel semi-axial gears installed in it, a cross and four satellites.
The hubs of the driving wheels are fastened with nuts on the casings of the axle shafts (Fig. 4.28). The inner splined ends of the latter are inserted into the holes of the side gears of the differential, the outer splined ends are fitted with flanges attached to the hubs on studs. They are bolted to the discs of twin road wheels and a cast-iron brake drum. Pads with friction linings are pressed against it during braking. The hub rotates on two tapered roller bearings.
The foot brake device is similar for the front driving and rear steered wheels. Inside each brake drum, two pads are mounted on the axles on the support disc. When compressed air is injected into the brake chamber, the expanding fist rotates and pushes the pads apart, overcoming the resistance of the coupling spring. To brake, the air from the brake chambers is released into the atmosphere, and the springs press the pads away from the drum.
The stroke of the rods of the brake chambers of the left and right running wheels should be normally 20-25 mm and not more than 35-40 mm.
The wheel brake drive is pneumatic, single-wire (Fig. 4.29). The brake pedal is connected by levers and rods 9 s brake valve 10. When you press the pedal, the valve opens and compressed air enters the wheel brake chambers. The air is supplied by a two-cylinder piston-type compressor 1 with a water-cooled head. Water is supplied through hoses from the engine cooling system. The air pressure in the pneumatic system is 700-740 kPa (7-7.4 kgf/cm2). When the pressure rises above this value, the regulator stops the air supply to the system. When the pressure drops to 560-600 kPa (5.6-6 kgf / cm2), the air supply to the system is resumed. In order to equalize the pressure in the system, a score of 8 compressed air is provided. Air is supplied to the rear wheel brakes through hoses. Air is supplied through the tube to the cab wipers. For control there is a manometer. The crane serves for air selection.
Rice. 4.27. 4008 Main Drive and Differential
Rice. 4.28. Front wheel hub
The brake drum of the hand brake is mounted on output shaft reverse mechanism. The drum is covered by a steel brake band with friction lining. The tips of the tape are unclenched by springs, as a result of which there is a small gap between the tape and the drum in the unbraked state (0.8 mm in the middle part). The belt tension is adjustable with a bolt. The movement of the handbrake lever by means of the rod connected to it causes the pressure cams to rotate, the brake springs are compressed and the belt is pressed tightly against the drum.
The rear wheels are steerable, have a balancing suspension. The steering scheme used on the 4008 autoloader is fundamentally the same as in fig. 4.3, a. The force reported by the hydraulic booster is transmitted by a longitudinal steering rod to the left steering knuckle lever. The steering trapezoid lever is fixed on the same fist and from it the force is transmitted to right wheel through the tie rod.
The steering mechanism and power steering are the same as those discussed above and are shown in Fig. 4.3,6 and 4.4. The hydraulic steering system uses a gear pump, the performance of which is 43% higher than that of forklift pumps with a lifting capacity of 32-50 kN (3.2-5 tons). The hydraulic booster safety valve is adjusted to 0.7-104 kPa (70 kgf / cm2).
Rice. 4.29. Pneumatic system diagram
The electrical circuit differs from that shown in fig. 4.14 by the fact that there are foot and manual light switches (instead of one) and the inclusion of the starter depends on the position of the ignition switch. The starter with a reverse clutch is activated when the traction relay is activated, mounted on its housing. The forklift is equipped with three headlights, the position of which is adjustable: two front ones - on the outer frame of the forklift and a rear one - on the cab.
The telescopic two-frame forklift 4008 is hinged on the same frame brackets as the drive axle, and differs from the forklifts of the loaders discussed above, in addition to greater strength, by a somewhat advanced internal movable frame and carriage, the rollers of which are grouped in two in four carts. The rollers of the two lower bogies are cylindrical and roll on flat rails. The rollers of the upper bogies with a grooved rolling surface move along segment guides. Racks of the outer frame are formed by each of the two elements having a cross section of channels arranged by shelves to each other. The racks of the inner frame consist of one element of the I-section. The inner shelf of the I-beam is placed between the walls of the channels of the rack of the outer frame. All rollers (4 pcs.) of the inner frame also have a grooved rolling surface and roll along the segmental guides of the outer frame racks. The carriage is suspended on two leaf chains. Tilt cylinders are installed using L-shaped cast steel brackets attached to the frame of the lift truck by the base.
The working fluid is supplied to the hydraulic cylinders of the cage grab (grab), suspended on the boom, on forklifts 4008 and 4028 through the rear oscillating supports, made of tubular, and then through two pipelines laid along the boom.
The scheme of the hydraulic system of the forklift is conventional (see Fig. 4.10), but without the hydraulic lock of the lifting-lowering cylinder. To limit the speed of the load during lowering, a throttling valve is provided through which the working fluid flows from the said cylinder to the drain. A manometer is installed to control the pressure in the hydraulic system.
The 4008M model autoloader, manufactured since 1976, has been improved compared to the machine discussed above and has the following design differences. The front drive axle is used from the MA3-503A car, it contains single-stage main and wheel gears with bevel and cylindrical gears with a total gear ratio of 8.28. The front wheels are discless. cardan shafts used from cars ZIL-157K and MA3-503A (shortened). Shoe parking brake with a mechanical drive, acts on the transmission and is installed on the drive gear flange front axle. In the power steering system, a right-hand gear pump of the NSh-32U type with a working volume of 31.7 cm3 was used. In the hydraulic system of the forklift, a gear pump of higher productivity of the NSh67-K type of left rotation with a working volume of 69 cm3 is used. The safety valve of the hydraulic distributor is adjusted to a pressure of 13-7-13.5 MPa (130-I35 kg/cm2). The capacity of the working fluid tank has been adjusted to meet the needs of hydraulic drives and reduced to 140 liters. A ST230-I type starter with an increased power of 1.55 kW (2.1 hp) and a C311 type horn were installed. The technical characteristics indicators have been improved: the length with an arrow and the width have been reduced by 100 and 40 mm, respectively; the speed of the load during lifting is increased on the forks to 0.117 m/s, on the boom to 1.67 m/s and in the grab to 1.42 m/s; the speed of the forklift has been increased to 10 km/h with a load and up to 16 km/h without a load.
