4 device, operation and maintenance of components of buses MAZ-103, MAZ-107
4.1 power unit of buses MAZ-103, MAZ-107, its systems and drives
A description of the engine, HMF, clutch and gearbox, as well as instructions for their operation and care, are given in the Operating Instructions for the respective units. If there are disagreements between this Manual and the Instructions for the units attached to the bus, then be guided by the latter.
The power unit is located in the rear overhang on the left side at an angle to the longitudinal axis of the bus.
The complete set of buses with power units is given in table. 1.1.
4.1.1 suspension of the power unit of buses MAZ-103, MAZ-107
The suspension of the power unit effectively reduces shock loads when driving on rough roads and completely dampens the reactive moments that occur during engine operation.
The power unit is attached to the frame of the bus on four supports (two front and two rear). Each support consists of a rubber-metal shock absorber 2 (Fig. 4.1.1.1), bolted to the frame bracket. The power unit is mounted on supports through the engine brackets with bolts and nuts, after tightening the nuts they are locked with cotter pins.
SERVICE OF THE SUSPENSION OF THE POWER UNIT OF BUSES MAZ-103, MAZ-107
When carrying out TO-1, check the fastening of the brackets, as well as the fastening and condition of the shock absorbers of the suspension of the power unit, if necessary, tighten the threaded connections with a regulated moment:
Nuts 5 (Fig. 4.1.1.1) of the power unit mounting bolts must be tightened to a torque of 110...140 Nm and locked with cotter pins;
The nuts of 4 bolts for fastening the supports to the frame brackets must be tightened to a torque of 25 ... 32 Nm.
Figure 4.1.1.1 - Power unit supports with Daimler engine:
1 - engine bracket; 2 - shock absorber assembly; 3 - frame bracket; 4, 5 - nut
4.1.2 engine fuel supply system
The engine fuel supply system, the diagram of which is shown in fig. 4.1.2.1, serves to supply, filter and accurately dose fuel in various engine operating modes. A description of the device and repair of the power system devices is given in the Operating Instructions and the Engine Repair Manual.
Fuel from the fuel tank 2 during engine operation is sucked in by the engine fuel priming pump through the coarse fuel filter 5 and the fine fuel filter. From the filter, fuel enters the engine. Excess fuel, and with it the air that has entered the system, is discharged through the fuel line to the fuel tank.
On buses with a Daimler engine, a manual fuel priming pump is built into the fuel pre-filter.
The supply of fuel necessary for the operation of the engine, PZD and air heaters is located in the fuel tank, which is installed on the right side of the bus.
The fuel tank consists of a body 1 (Fig. 4.1.2.2), a filler neck 3 with a strainer 4 and a fuel intake 2. Inside the fuel tank there are baffles that increase the rigidity of the tank, prevent fuel shaking and foam formation. At the bottom of the tank
plug 5 is screwed in to drain the sludge. The fuel level in the tank is controlled by a gauge located on the instrument panel. The control lamp lights up if about 30 liters of fuel remain in the tank. The pointer receives a signal from a rheostatic fuel level sensor installed in the fuel tank.
The filler neck is closed with a sealed plug, in which the inlet and outlet valves are installed. The exhaust valve opens at a pressure of 5.7 ... 18 kPa, preventing an increase in pressure in the tank when the fuel is heated, the inlet valve opens at a vacuum of 1.6 ... 3.5 kPa, preventing the vacuum that occurs when the amount of fuel in the tank decreases.
Polyamide low-pressure fuel lines are laid in protective shells and fixed to the bus chassis with clamps. The method of connecting polyamide fuel lines with fittings is shown in fig. 4.1.2.3. When assembling the joint, grease the clamping ring 4 with LOCTITE 5900 sealant.
The coarse fuel filter with a water separator is designed for preliminary purification of fuel entering the fuel system. Daimler-powered buses are equipped with a RACOR fuel pre-filter with a built-in manual fuel priming pump. The filter is equipped with electric heating, which operates in automatic mode. The filter is installed on the suction line of the power supply system and is mounted on the frame bracket.
A heating element is installed in the filter housing, which effectively heats the fuel flow, melting the released paraffin. The filter heater functions when the ignition key is in the "I" position in automatic mode. When the ignition key is turned to position "0" or "III", the heater switches off automatically.
Along with the coarse fuel filter, the engine is equipped with a fine fuel filter. The maintenance procedure for the fine fuel filter is given in the "Engine Operation Manual".
The rear drive axle MAZ-103 (Figure 5.3) is made according to the classical scheme with a double spaced main gear and a bevel gear offset from the transverse axle of the axle. It consists of a crankcase, a central bevel gear, planetary wheel gears and shoe brakes.
1 – control plug; 2 – wheel drive cover; 3 – cracker; 4 – emphasis; 5 – drive gear; 6 – carrier; 7 – lock-nut; 8 – hub bearings; 9, 15 - cuffs; 10 – oil catcher; 11 – brake shoe; 12 – spring; 13, 17 – spherical bearing; 14 – fist support front; 16 – expanding fist; 18 – rear knuckle support; 19 – butter dish; 20 – adjusting lever; 21 – brake chamber bracket; 22 – crankcase of the bridge; 23 - bevel gear; 24 – control valve; 25 – brake shield; 26 – caliper; 27 – pad axis; 28 – bronze bushing; 29 – ABS sensor; 30 – brake drum; 31 – bolt; 32 - trunnion; 33 – hub; 34 – axle shaft; 35 – driven gear hub; 36 – screw, 37 – driven gear; 38 – bearing; 39 – satellite; 40 – satellite axis
Drawing5 . 3 – Drive axle MAZ-103
The wheel gear is a planetary gearbox consisting of spur gears with external and internal gearing. pinion gear 5 mounted on axle shaft splines 34. Four satellites 39 on bearings 38 installed in carrier sockets 6. The carrier is rigidly connected to the wheel hub 33. driven gear 37 through the hub 35 rigidly connected to the trunnion 32, the hub is kept from axial movement by a nut 36. Half shaft movement 34 limited to breadcrumbs 3 and emphasis 4.
Rear wheel hub 33 mounted on a trunnion 32 on roller tapered bearings 8. Bearing adjustment 8 carried out by a nut 36, which is secured with a locknut 7 . cuffs 9 do not allow oil from the axle housing to enter the shoe brakes. trunnion 32 fastened to the crankcase with bolts 31. For hub bolts 33 installed brake drum 30. Into the wheel drive cover 2 check plug screwed in 1 and an oil drain plug.
Shoe brakes placed between the caliper 26 and brake drum 30. pads 11 mounted on axles 27 in the caliper 26 on bronze bushings 28 and pressed against the profile of the expanding fist 16 return spring 12. Fist 16 installed in supports 14 And 18 on spherical bearings 13 And 17. At the end of the expanding knuckle 16 adjustment lever installed 20 , inside of which there is a mechanism for automatically maintaining the set gap between the pads 11 and brake drum 30.
Oil catcher 10 serves to collect and discharge to the outside through the channel in the hub 33 leaking through cuffs 9 oils. butter dish 19 designed to supply lubricant to the spherical bearings of the expander knuckle support, to lubricate the bearing of the front support 14 expanding knuckle and shoe axles 27 oilers and control valves are installed on the brake shield.
bevel gear 23 located in the crankcase of the bridge 22 From the left side. It consists of a pair of bevel gears 3 And 17 with circular teeth and differential. The transmission angle is 90°. pinion gear 17 installed in a glass 20 on two tapered roller bearings 18 And 21, adjustable with shims 1. The moment on the gear is transmitted through the flange 23. cuffs 22 designed for flange sealing. driven gear 3 attached to the differential cup 5 bolts 9. Pins 10 are designed to limit the deformation of the bearings of the differential bearings. Inside the differential cups 5 And 13 accommodates a bevel differential with two side gears 14 and four satellites 7 , rotating on the spikes of the cross 6.
Conclusion: in the course of the work, the designs of gear main gears, the cross-axle differential of cars and buses, as well as their axle shafts were studied.
An improved design of an air spring with an air damper for self-regulation in terms of amplitude and frequency of oscillations of the Volzhanin and KAvZ bus systems is presented. In the spring, an elongated piston is welded from two serial parts and made of PTFE-4 for operation without lubrication. Check valves are closed with thin elastic tubes, as an elastic rod - a wire with a diameter of 3 mm from spring steel. The operating modes and dynamic elastic characteristics of the air spring are shown. The optimal design parameters were tested on the stand. Suspension hydraulic shock absorbers can be abandoned, which simplifies the design, reduces costs and increases reliability.
1.1 Information about the bus MAZ-103
Rice. 1. Bus MAZ-103
Brand:……………………………………………………………………MAZ-103
Manufacturer:……………………… RUE "Minsk Automobile Plant"
Body type:…………………………………………………………………bus
Number of doors:……………………………………………………………………...3
Overall dimensions, mm………………………………………..11985-2500-2838
Outer turning radius, mm……………………………………………11300
Number of seats…………………………………………………...24
Maximum speed, km/h………………………………………………..…80
Engine……………………………………………….Deutz BF6M1013EC (E2)
Displacement, l:………………………………………………………………..7.12
Engine power, kW (hp)………………………………………... 174 (237)
Gearbox………………………... Voith Diwa D851.3E (automatic)
Wheels………………………………………………........... disk, 8.25х22.5
2 General view and arrangement of the MAZ-103 bus suspension units
When analyzing the suspension of the MAZ-103 bus, we select the main elements and present a detailed arrangement of the units in order to identify the main failures and malfunctions during the operation of the MAZ-103 bus.
2.1 Front suspension
Rice. 2. MAZ-103 front suspension device
1-Cylinder air suspension assembly; 2.3-Nut M30x1.5-6H; 4-Washer 12OT; 8-Bolt М12х1 25-6Н; 9-Nut М8-6Н; 10-Washer 8T; 12-Bolt М8-6gx50; 13-Splint 1.6x20; 14.18-Clutch; 15-Washer 6; 16-worm clamp; 17-Axis; 19-Thrust; 20-Shock absorber; 21-Hub with a fist and brakes, right; 22-The base of the front suspension; 23-Amplifier; 24-Nut; 25-Nut М10-6Н; 26-Screw М10-6Н; 27-Splint 5x36; 28-Nut М24х2-6Н; 32-Traction transverse; 33- Left hub with fist and brakes; 34-Sleeve; 35-Traction transverse; 37-Bolt M18x1.5-6N; 38-Bolt 3M14x1.5-6gx50; 39-flange; 41-Sleeve; 42-Key 6x9; 43-Finger; 44-stand; 45-Piston; 46-Buffer; 47-Sleeve; 48-Washer 14; 49-Washer 14L; 50-Bolt M14x1.5-6gx50; 51-Rubber cord sheath; 52-flange; 53-Bolt M18x1.5-6N; 54-Nut M18x1.5-5H6N.
2.2 Front suspension
Rice. 3. Front suspension device MAZ-103
1-Axis front; 2,3-support; 4.5-reactive rod; 6-shock absorber; 7-Cylinder air suspension assembly; 8-Body position regulator; 9-Regulator rod; 10-Axis; 11-Sleeve; 12-flange; 13-Ryachag; 14-Bolt 3M14x1.5x6gx50; 15-splint; 16-Nut М8-6Н; 17-Bolt M8x6gx50; 18-Bolt M8x6gx25; 19-Washer 8T; 20,28-Buffer; 21-Washer; 22-Bolt 3M24x2-6g-60; 23-Splint 1.6x400; 24-Splint 5x36; 25-Nut M30x1.5-6N; 26-Flanets; 27-Piston; 29-Sleeve; 30-Bolt m14x1.5-6; 31-Washer 14; 32-Washer 14; 33-Rubber cord sheath; 35-Tip right; 37-Bolt; 38-Washer; 39-Nut.
2.3 Suspension bar
Rice. 4. The device suspension rod MAZ-103
1-Head; 2-Bolt M12x1.25-6gx60; 3-rod; 4,5-Hinge; 6,7,16,18,19-Ring; 8-rod head; 9-Hinge; 10-Washer 16OT; 11-Bolt M16x1.5-6gx60; 12-Ring 140; 13-Nut M12x1.25-6gx60; 14-Washer 12OT; 15-Pipe; 17-Hinge.
2.4 Rear suspension
Rice. 5. Rear suspension device MAZ-103
1-Traction transverse; 2-Beam; 3-Axis lock cylinder; 4-Hub; 5-Brake right; 6-Brake left; 7-lid; 8-Gasket; 9-Washer; 10-Nut; 11-Bolt M12x1-6gx90; 12.13-Knuckle swivel; 14-Lever tropezia left; 15-Lever tropezia right; 16-Shock absorber; 17.18-reactive rod; 19-Pneumatic balloon; 20-flange; 21-Plate; 22,29,30-Nut M32x2-6N; 23-Bolt M24x2-6gx90; 24,25,26,27-Bolt; 28.31-Washer 4; 32,33,34-Washer 16OT; 35-Splint 5x45; 36-Splint 6.3x71.
The MAZ-103 city bus was developed as an alternative to similar Hungarian, Russian and Ukrainian-made vehicles. The first model produced by the Minsk Automobile Plant rolled off the assembly line in 1996. The low floor position and the absence of steps make it easier for passengers to get on and off at stops. The car combines quality, comfort and affordable price. It is operated in Belarus, Russia, Europe and Asia.
Specifications
Engineers took the best models of urban transport that were used at that time as the basis for the product, adapting it to poor quality roads.
Bus MAZ-103-485 has the following specifications:
- length - 1200 cm;
- width - 250 cm;
- height - 250 cm;
- weight without refueling - 18000 kg;
- wheelbase front and rear - 205 and 185 cm;
- maximum load on the front and rear axles - 6500 and 1500 kg;
- turning radius - 1125 cm;
- floor height - 34 cm;
- passage between the seats - 80 cm;
- number of seats - 25;
- passenger capacity - 100 people;
- maximum speed - 110 km / h;
- wheels - disc 8.25 × 22.5 with tires 11 70R22.5;
- Suspension - independent pneumatic with telescopic shock absorbers.
A feature of the bus MAZ-103-075 is the rear location of the power plant. Due to this solution, it was possible to reduce the landing of the car and make it more stable when cornering and strong crosswinds.
Engine Description:
- type - diesel;
- brand - MMZ D-260.5;
- power - 230 hp;
- working volume - 6.4 l;
- fuel consumption per 100 km in urban mode - 26 l;
- gearbox - mechanical;
- cooling system - water forced.
The power plant is fixed to the frame using four supports with shock absorbers. Due to this, vibration in the cabin is practically not felt. A later model of the MAZ-105 articulated bus is equipped with an OM906LA engine with an environmental class Euro-5 and a ZF automatic transmission.
See » Characteristics of the onboard vehicle MAZ-5336 and TOP-4 of its modifications
Equipment
The base model at the car factory is equipped with two rows of seats. On the left are double seats, and on the right are single seats. The all-welded frame is resistant to vertical and torsional loads. Cars of the last years of production are equipped with Mogilev single-chamber double-glazed windows with a coating that reflects ultraviolet. Thanks to this, a comfortable temperature is maintained in the cabin in the summer.
The MAZ-105 bus is equipped with the following options:
- automatic shock absorbers that level the body when the load difference and driving on an inclined road;
- tinted glass that cuts off solar radiation;
- plastic seats resistant to impacts and sharp objects;
- ceiling fans that remove polluted air from the cabin when idle in traffic jams;
- LED board broadcasting information about the route of movement and advertisements;
- plastic handles located at different heights, convenient for tall and short passengers;
- automatic fire extinguishing system that works without human intervention;
- interior heater with thermal barrier on the doors.
The manufacturer produces school buses with two rows of seats and a reinforced frame. For the needs of public utilities, mobile bathrooms are produced, which go to crowded places on city streets and squares.
new bus starts back in 1992. Then the MAZ plant, known in the world as a manufacturer of a wide range of trucks, had no experience in the development of passenger transport. The agreement with the well-known German manufacturer Neoplan on cooperation in production allowed the Minsk plant to obtain a license for production and the necessary technologies, which significantly reduced the time and cost of development at the initial stage.
This step for the young republic was not from the field of image, and not even in the field of economics - its own bus became a vital necessity, since the Hungarian Ikarus, widespread in those years in the USSR, with the collapse of the CMEA, began to curtail production and supplies to the CIS countries, including, and in connection with the difficult economic situation in the republics of the former USSR, including with the currency. Depreciation rapidly brought the Ikarus bus fleet out of service. Replacement was required, and cost-effective and operational.
As a result, the largest machine-building plant successfully mastered independent production and already in 1993 the first six Belarusian buses, which were a copy of the basic model, rolled off the assembly line. However, the final cost of the assembled buses turned out to be significantly high - about 200 thousand dollars, which made the project unviable, especially since the former CMEA republics sought to "cheap" their old "Ikaruses". Plus, the life of the equipment in conditions of non-ideal roads turned out to be low. And as a result, adaptation to local conditions and local components began.
The result of the work was the launch in 1996 of the MAZ 103 low-floor bus into mass production. Due to the reduction of imported components to a minimum (up to 10%), the price turned out to be more than two times lower than competitors, the cost of ownership also decreased, maintainability and service life increased in the operating conditions of Belarus and CIS countries.
It should also be noted that the Maz 103 was the first low-floor bus produced in the CIS countries. It turned out to be roomy, safe and comfortable - meeting world standards, thanks to which it has gained popularity outside the Republic of Belarus.
Technical features
Scheme bus chassis made according to the classical scheme, with a rear driving axle, with a bevel gear.
MAZ-103 is already presented today in several modifications - for suburban passenger transportation, with a different number of doors (without a back door), with a different number of seats, and with different capacities.
Bus seat arrangement MAZ 103 is made according to a three-row scheme - double on the left and single on the right. Opposite the middle door is a storage area.
Driver's cab with an ergonomic arrangement of controls, with a comfortable seat and adjustable steering column. The dashboard has no frills, but is made at a modern level and is fully consistent with the task of reliable and comfortable control.
Historically, the bus began to be equipped with engines of the Minsk Motor Plant, with a capacity of 230 hp. They were unnecessarily large, heavy, lacking power, and the noise was just above what was desired. For these reasons, in the early 2000s, Renault engines were installed on MAZ 103 buses - more reliable and powerful (250 hp), there were also DEUTZ and Mercedes modifications.
Power plants of the line
Currently, only Mercedes-Benz engines (286 hp or 326 hp) are installed. Units of a well-known manufacturer from Germany are distinguished by a high degree of reliability and efficiency and comply with more stringent environmental standards (Euro-5).
In terms of gearboxes, the bus was initially equipped with a 6-speed self-produced one, but it was not compatible with a number of engines, which forced the designers to look for other options, as a result, most buses were equipped with a 5-speed Praga gearbox. Recently, configurations have been offered with a manual transmission manufactured by ZF or an automatic from Voith or Allison.
Long-term operating experience of the model has shown its reliability and efficiency. Low comparative cost of operation and cost of spare parts. In addition, spare parts can be ordered through a developed system of official dealers of the plant.
The price of MAZ 103 at the end of 2015 is from 6,500 thousand rubles for a new bus.
Basic elements of a complete set of a series
- Webasto independent liquid engine heater 30kW used for engine preheating and interior heating
- Driver cab independent air heater 2.0-2.2 kW (Webasto or Eberspacher)
- Anti-lock braking system ABS
- Traction control ASR
- Radio equipment without radio: microphone, amplifier and 4 loudspeakers
- Thermal soundproof ceiling
- Anti-corrosion treatment of the bottom and hidden cavities
- Folding ladder for wheelchair access
- Equipment and attachment for one wheelchair
- Forced body tilt system "Kneeling"
- The driver's seat on an air cushion, adjustable, manufactured by OJSC "MAZ"
- Wear-resistant coating "Grabiol"
- Galvanized sheet on the sides and roof
- Stop request buttons
- Screw-in towing forks
- Partition separating the driver's workplace from the passenger compartment and dividing the doorway into two parts, without exit to the passenger compartment
Advantages and disadvantages
The advantages of the model include, in addition to the above, high visibility in the driver's cab and high maneuverability.
Thanks to the low floor, disembarkation and embarkation of passengers is carried out quickly and conveniently, stopping time is reduced.
The disadvantage of the bus can be attributed to the large dimensions of the engine located in the rear of the cabin, because of which it was not possible to implement a stepless entrance, equally low for all three doors. As a result, the floor height for the rear door was 580 mm, against 360 mm for the front and middle. Also, a 220 mm high step was formed for the rear door.
