GENERAL INFORMATION
1. Features of the design of cars LM-68 and LM-68M
The Carriage Repair Plant (VARZ), now the City Electric Transport Repair Plant (ZRGET), has been producing four-axle LM-68 cars since 1968 (Fig. 1). The design of these cars differs from the previously produced cars LM-33, LM-49, LM-67 by the use of electrical equipment that allows the cars to be operated according to the system of many units, and swivel bogies with rubberized wheels, rubber elements in the bogie assemblies and spring suspension, installation of rail electromagnetic brakes for emergency braking, a ventilation system and calorific heating due to the use of heat from starting-braking resistors and a number of other devices aimed at ensuring traffic safety, smooth silent running, creating amenities for passengers and conditions that facilitate the work of drivers.
A significant difference between the LM-68 car and the previous types of Leningrad cars, in particular the most modern
LM-57 is its scheme. Instead of direct control, automatic control was adopted, which makes it possible to operate trains of two or more motor cars according to a system of many units. In addition, the requirements for modern urban transport have been met: the aesthetic qualities of the exterior of the car, the modernity of its style characteristics, harmony with the general ensemble of the city, manufacturability, constructiveness of the solution of the body and its components. The interior of the cabin satisfies the psycho-physiological requirements of a person for this type of transport. The car was expanded without changing its dimensions by creating an additional inclination of the upper trench belt. The design of the chairs, their shape, the location of the handrails are made taking into account the anthropometric data of a person.
Rice. 1. General view of the LM-68 car
Since 1976, ZRGET began the production of modernized LM-68M cars (Fig. 2). Modernization provides for an increase in quality and operational indicators
The car and the elimination of remarks identified during the period of operation of the LM-68 car. The body has been given a more rigorous outline due to the elimination of protruding parts on the frontal ends of the front and rear platforms and in the area of the middle doorway. In addition, the roof was reconstructed, in which roof glazing was eliminated and the slope of the arches was increased. Along the roof are “five ventilation hatches: four above the passenger compartment and one above the driver's cab. The hatches above the salop open, of which the first one is
direction of travel, and the other three against it. Luke
Above the cab, depending on the need, it opens but to the direction of movement and against it, as well as vertically upwards. Due to the elimination of the roof glazing, the height of the side trenches has been increased and their slope has been changed. Such
The decision made the interior brighter and more spacious. The car floor is aligned in one plane. The seats are installed on individual cabinets, inside which S-shaped heating elements with a power of 400 W each are mounted. The driver's cab is somewhat expanded due to the assignment of the rear wall; in the niche of the cabin along its height, panels with electrical equipment are marked. The control panel and the layout of the controls remained largely unchanged. .The capacity of the cabin heating system has been doubled due to the additional installation of sectioned heating stoves. The location of the undercarriage equipment has undergone a fundamental change, consisting in the fact that the equipment subject to frequent inspection is installed along the starboard and port sides. Electric power circuits and control circuits have undergone minor changes compared to the circuits of the LM-68 car. The door lock is provided, which excludes the movement of the car with open doors. Electric wires of the PGVA brand in the control circuits were replaced with wires of the PS and PPSRM brands.
ZRGET is preparing the production of LM-68 and LM-68M cars with a thyristor-pulse control system. At present, several such cars have been built, which are in pilot production. The thyristor-pulse control system has a number of advantages. It provides smooth automatic rheostatless start, smooth excitation control, regenerative
braking to a complete stop with the possibility of replacing it with a rheostatic electric. The impulse control system differs from the contactor-rheostat one in a set of equipment: the traction motor with mixed excitation is replaced by a motor with sequential excitation, the group rheostat controller and starting resistors are replaced by a thyristor unit, a control unit and capacitor units.
A compressor is used as a source of compressed air, taking air through an air filter. Compressed air from the compressor through the oil-moisture separator and check valve enters two spare high-pressure tanks. A safety valve is installed on one of the tanks. The AK-11B electro-pneumatic pressure regulator and the reverser drive cylinder are connected to the pipeline going from the reserve tanks to the cabin.
From the high-pressure reservoirs, through a disconnect valve and a pressure reducing valve, compressed air enters the low-pressure system with a low-pressure working reservoir. The low-pressure reservoir is connected to the switching valve and brake cylinders through disconnecting valves and electro-pneumatic valves for after-braking.
The mechanical brake from the pneumatic drive is used for service braking and brakes the car at low speeds. In addition, it is used to slow down the car in case of a faulty electrodynamic brake, which is a service brake. The control of the mechanical brake from the pneumatic drive is carried out automatically using the valves for re-braking. In addition, the car is provided with a direct-acting high-pressure line from the driver's crane, which is connected through a switching valve to the brake pneumatic cylinders.
The low pressure system also includes an automatic brake switch designed to prevent sudden braking when applying a mechanical brake from a pneumatic drive to electrodynamic braking.
The air pressure in the pneumatic system is measured by manometers. The air supply to the bell vibrator is carried out by the driver's crane. The exhaust air is vented to the atmosphere through a silencer.
Topic number 2. The process of obtaining compressed air. Motor - compressor "EK-4V".
Lecture 2 hours.
Consider the principle of operation of the compressor and the mechanism for obtaining compressed air. Tram rolling stock uses reciprocating compressors, the main parts of which are: a cylinder, a piston, suction and discharge valves and a crank mechanism.
The process of obtaining compressed air can be divided into three independent stages:
· Stage 1 -suction. When the piston moves from left to right (top to bottom), air enters the cylinder through the suction valve, filling the cylinder space above the piston crown. In this case, the air pressure remains constant.
· Stage 2 - compression. Under the action of an external force applied to the piston, the air is compressed, its volume decreases.
· Stage 3 - injection. This is the process of expelling compressed air through a pressure valve into the system and compressed air storage tanks.
Having become acquainted with the process of obtaining compressed air, we will consider the purpose and design of the EK-4V motor-compressor, which is a single-stage two-cylinder compressor made in a single unit with an electric motor and a gearbox. The compressor has a horizontal arrangement of pistons and is driven by an electric motor "DK-408V" through two stage gearbox consisting of two pairs of helical gears. Reducer and compressor placed IN ONE BODY, the flange of which is fastened with studs and nuts to the motor housing.
FRAME cast iron compressor. He has window with three covers that are designed to access the compressor parts. The top cover is provided breather to connect the internal cavity of the crankcase with the atmosphere and eliminate excess pressure inside the crankcase.
cast iron CYLINDER BLOCK fastened to the body with studs. The outer surface of the cylinder block is ribbed for better cooling. The inner surfaces of the cylinders are machined to a high accuracy class, as they come into contact with the outer surfaces of the pistons.
CRANK MECHANISM compressor consists of two pistons, two horizontal connecting rods and a crankshaft.
Crankshaft has two necks, on which connecting rods are installed with a split head with a babbitt filling.
The crankshaft journals are located one relative to the other at an angle of 180 degrees. The crankshaft rotates in two ball bearings, one of which is installed in the housing, and the other is mounted in a special axle box, which simultaneously serves as a cover. A gearbox gear is mounted on the output end of the crankshaft with a key.
connecting rods made by stamping and have an I-section. Both parts of the lower split cover, which serves as a plain bearing, are pulled together on the neck of the crankshaft by tie bolts. An oil sprinkler is attached to one of the bolts. The second connecting rod head is one-piece. It has a pressed bronze bushing where the piston pin is inserted to connect the connecting rod to the piston.
Piston cast iron, has 4 grooves on the side surface, into which piston rings. The first two piston rings are called compression, they provide a reliable seal between the piston and the cylinder walls. The other two rings (with internal chamfers) are called oil scraper, they are designed to remove excess oil from the cylinder walls. The rings are made of cast iron, split and have elasticity, as a result of which they fit snugly against the walls of the cylinder.
The piston walls on the inside have lugs with holes for installing piston pins. The finger is held in the tides by steel spring rings.
Attached to the cylinder block VALVE BOX. It has installed two suction and two discharge valves, completely identical in design. The suction valve is required to suck atmospheric air into the cylinder. When the piston moves down (towards the axis of the crank mechanism), the valve plate compresses the spring and opens the air to the suction cavity, and then to the cylinder (suction process). When the piston moves back, the excess pressure in the suction cavity closes the suction valve plate and compresses the discharge valve spring, while the discharge valve plate opens air from the discharge cavity to the pressure line (injection process). If in the first cylinder air is sucked in from the atmosphere, then in the second - air is compressed and forced into the tanks.
VALVE consists of a seat with holes arranged around the circumference and a stud that serves as a guide for the annular reed valve. The valve plate is pressed against the seat by a conical spring.
Inner space valve box separated by a partition that separates the suction and discharge cavities. The suction cavity communicates with the atmosphere through an air filter, and the discharge cavity communicates with the air reservoirs through a check valve. All detachable connections of the body, cylinder block, valve box and covers are sealed with gaskets to prevent leaks.
To lubricate the compressor, compressor oil of grade 12M is used in winter and grade 19T in summer. When the crankshaft rotates, oil from the crankcase is captured by the sprinklers, creating an oil mist that settles on the working surfaces of the parts and lubricates them. The gearbox gears are partially immersed in oil and, when the compressor is running, they capture oil to lubricate the entire gearbox. In the lower part of the body there is a drain hole closed with a plug.
The performance of the motor - compressor at a crankshaft speed of 320 rpm. is 350 l/min. The maximum air pressure is 8 - 9 atmospheres. The operating mode of the unit is intermittent. The operating cycle of the MK is approximately 10 minutes, the switching period is 50%.
Air is sucked in through the air filter located in the passenger compartment (on the floor under the seat on the right in front of the middle door). The filter is a metal housing in which a filter element is mounted, consisting of two steel meshes, between which oiled horsehair is laid.
Control signs of proper operation of the motor-compressor:
· The compressor raises the pressure in the pneumatic system from 0 to 6 atm. in 3 - 5 minutes.
No extraneous noise and knocking during compressor operation.
Possible malfunctions of the motor-compressor:
· Valve failures.
Destruction (breakdown) of sealing gaskets.
· Wear of liners, rings, bearings, crankshaft, gear.
Lack of lubrication.
The motor-compressor is located on the right under the car in front of the middle door.
Topic number 3. Electropneumatic pressure regulator "AK-11B".
Lecture 2 hours.
Electropneumatic pressure regulator "AK-11B" is designed to automatically turn on and off the motor-compressor, depending on the pressure of compressed air in the pneumatic system. Located in the driver's cab on the partition on the right.
Consider the main components of the electro-pneumatic pressure regulator "AK-11B":
· Base made of plastic, with a seat for adjusting the spring and a guide for mounting the movable stop.
· Plastic casing (cover).
· Two cylindrical racks.
Fixed bar.
· Movable bar.
· Adjusting spring.
· Adjusting screw.
· Movable stop.
· Camera-flange.
· Rubber diaphragm.
· Two-arm lever.
· Movable contact.
· Closing spring.
Fixed contact.
· Screw stop.
Rectangular stand.
· Flexible shunt.
Electropneumatic pressure regulator "AK-11B" is mounted on a plastic base and closed with a plastic casing. Two cylindrical posts are fixed on the base, connected by a fixed bar. Between the uprights there is an adjusting spring, which is fixed at one end in the socket of the movable stop, and rests against the movable bar at the other. The stop can move in the guide, also fixed on the base. The lower end of the movable stop passes through the base into the chamber-flange, reinforced from below on the base. A rubber diaphragm is laid between the chamber and the base. The flange chamber is connected to spare tanks.
The upper end of the movable stop is pivotally connected to a two-arm movable lever, on which the movable contact rests. The closing spring firmly presses the moving contact against the fixed contact. The fixed contact is fixed on the base. In the open position, the movable contact abuts against a stop screw fixed on a rectangular post. The stop screw allows you to adjust the contact gap and pressure drop (lower limit).
The movable stop moves in the guide, and when the compressed air pressure is less than the shutdown pressure, it is in the lowest position. At the same time, the movable lever keeps the contacts closed, the compressor works, the pneumatic system is filled with compressed air. As soon as the compressed air pressure becomes equal to the cut-off pressure, the movable stop overcomes the resistance of the adjusting spring, compresses it and turns the two-arm lever counterclockwise. The contacts open, the compressor stops working.
As soon as the compressed air pressure has dropped to the switch-on parameter, the adjusting spring is released, the movable stop goes down, the two-arm lever turns and the movable and fixed contacts close again. The compressor starts working, the whole process is repeated again.
Control signs of the correct operation of the AK-11B electropneumatic pressure regulator:
· Electropneumatic pressure regulator "AK-11B" includes a compressor at a pressure of compressed air in the pneumatic system 4 atm. and turns off when the compressed air pressure reaches 6 atm.
Possible malfunctions of the AK-11B electropneumatic pressure regulator:
· Adjustment of the electropneumatic regulator "AK-11B" is disturbed.
Mechanical jamming or freezing of "AK-11B".
Large air leakage due to diaphragm rupture.
Burning of contacts.
Topic number 4. Reducing, safety and non-return valves.
Lecture 2 hours.
· REDUCER VALVE.
The pressure reducing valve is designed to create and maintain a constant reduced pressure of compressed air, which is supplied to the brake cylinders and is used to drive a mechanical brake during service braking.
The pressure reducing valve body consists of two parts: an upper part and a lower part. Both parts are connected with screws.
At the top of the pressure reducing valve are:
valve.
· Valve seat.
A spring that presses the valve against the seat.
· A plug with a groove for installation of this spring.
· Sealing leather laying.
At the bottom of the pressure reducing valve are:
· Piston.
· Adjusting springs.
· Brass diaphragm.
· Upper and lower centering (thrust) washers for installation of adjusting springs.
· Adjusting sleeve with thread for adjusting the pressure reducing valve.
· Locking screw to prevent spontaneous unscrewing of the adjusting cup.
Consider the operation of a pressure reducing valve. Under the action of the adjusting springs, the diaphragm flexes upward and the valve at the top of the pressure reducing valve is in a raised position. Compressed air from the pressure line enters the low pressure system and replenishes it. As soon as the pressure on the diaphragm equalizes with the pressure of the adjusting springs, the diaphragm flexes downward, the valve lowers into the seat¸ the valve spring presses it firmly against the seat, the hole closes, and air access to the low pressure system stops.
As air is consumed or possible leaks, the pressure above the diaphragm will decrease again and the supply of low pressure compressed air will again be replenished. Thus, the pressure reducing valve maintains a constant pressure in the low pressure pipeline. Adjustment of the low pressure air parameter is carried out by rotating the adjusting cup in the desired direction. Control is carried out according to the readings of the low pressure manometer. Low pressure air parameters - 2.8 - 3.2 atm.
The pressure reducing valve is located in the driver's cab on the lower right side of the pipeline.
Possible malfunctions of the pressure reducing valve:
· Air leakage due to loose fastening at the joints, or destruction of the diaphragm.
· Wear and tear of the valve and seat, spring sagging.
Clogged or frozen pressure reducing valve.
Actions of the driver in case of malfunction of the pressure reducing valve:
· In the event of an air leak, shut off the air supply using the disconnect valve, use the driver's valve.
· If the pressure reducing valve is defective, the operator's crane must also be used.
· SAFETY VALVE.
Safety valve designed to protect against excessive increase in air pressure in the pneumatic system of a tram car in the event of a malfunction of the electric pneumatic pressure regulator. Installed on the first spare tank on the rear platform of the tram car.
The valve consists of two parts: the upper part and the lower part, which are interconnected by a threaded connection. At the bottom of the safety valve are:
· Valve seat.
valve.
· A centering washer for installation of an adjusting spring.
At the top of the safety valve are:
· Adjusting spring.
· Adjusting plug.
· Threaded cap with valve sealing tool.
The valve is pressed firmly against the seat by means of an adjusting spring, the pressure of which can be changed by means of an adjusting plug. After adjustment, the plug is closed with a lid and sealed. The valve is regulated on pressure of 7 atm.
When the pressure in the pneumatic system of the car rises above the limit, the compressed air pressure on the valve from below will be greater than the pressure of the adjusting spring on the valve from above. The valve rises in the seat and part of the air from the reserve tank through the holes in the upper part of the safety valve body will escape into the atmosphere. The pressure in the tank will decrease, and as soon as it reaches an acceptable value, the valve will lower into the seat under the action of the adjusting spring and the air will stop.
Possible malfunctions of the safety valve:
· Wear, valve and seat wear.
Broken or sagging spring.
Clogged, frozen valve.
· Absence of a filling.
Historical reference
In the early 70s of the XX century, the Leningrad plant VARZ continued to improve the all-metal 4-axle tram car. Improving the quality and performance of manufactured trams continued to be at the forefront. The operation of the LM-68 showed a low margin of safety for the frame and body frame. In some cars, after several years of operation, deviations from the geometry of the body were observed in the area of the front and rear platforms. In December 1972, a technical assignment was issued for the development of a modernized LM-68M car.
Already in the next 1973, under the leadership of B.M. Kulakov, an experimental car was built. The body of the tram was given a more strict outline by eliminating the protruding parts on the frontal ends of the front and rear platforms and in the area of the middle door. The roof was also reconstructed, during which the roof glazing was eliminated, the height of the side windows was increased and their angle of inclination was changed. Five ventilation hatches were placed along the roof, one of which was placed above the driver's cab. The floor level was leveled in the cabin, the seats were installed on individual pedestals, inside of which heating elements were mounted, similar to the KTM-5M3 cars. The changes also affected the undercarriage equipment: the equipment subject to frequent inspection was placed along the sides of the car. To increase safety, blocking the movement of the car with open doors was introduced into the electrical circuits of the car.
An experimental car in 1973 entered the tram fleet. Smirnova. In 1974, 7 more LM-68M cars were built. The first 4 cars were equipped with asymmetric single-lever current collectors of the SVARZ plant, type AA-38-925. Some of the wagons were coupled into trains of two wagons according to the system of many units. In August 1975, an interdepartmental commission recommended the LM-68M for mass production. In the same year, mass production was launched. At cars with head. No. 10, turn signals in the frontal part of the body began to be installed above the headlights. In the same 1975, approximately from plant No. 25, soffit boxes began to be installed on the cars in the front and rear parts of the car with separate glass (dividing the end windows into two unequal parts), the bulwark hatch at the motor-compressor began to be made with deflectors. At the same time, the size of the vents in the cabin increased. In 1980, the rear door was expanded by eliminating a small window at the rear wall. In the same year, a number of changes were made to the electrical equipment in order to increase its reliability, and the ventilation of the traction motors was changed. In 1986, a batch of cars was produced with the removal of part of the electrical equipment into the car interior. Electrical devices were arranged in a specially installed cabinet on the left side of the car behind the driver's cab. Since 1987, such cars have been mass-produced. Cars with serial numbers 1992 and 1994 were experimentally equipped with TISU and coupled into a train according to the system of many units.
During the years of production, due to a shortage of some of the electrical equipment supplied by the Moscow Dynamo plant, some of the cars were handed over to the customer without traction motors, pantographs and some other components. Later, the cars were re-equipped at operating enterprises. At the beginning of 1983, there were 26 such cars in Leningrad. In the same year, an experimental trailer car of the LP-83 type was designed and built, which is an LM-68M car without a cab, which was replaced by a storage platform similar to the back one. The car did not contain electrical equipment, with the exception of the drum-shoe brake control circuits. The car was sent for testing to the tram depot. Skorokhodov. Tests have shown low reliability of the brake system and increased impact on the path of non-motorized bogies. Subsequently, such wagons were not built.
From 1988 to 1992, about 30 double-sided LM-68M cars were built. The cars received a second cabin in the rear, the back door was moved from the starboard side to the left, and the middle door was shifted one window back (two doors were installed on both sides of some cars). Two pantographs were installed on the roof, part of the electrical equipment was placed in the cabin in a cabinet behind one of the driver's cabs. 6 of these cars received the index 71-88G and were sent for operation in the village. Cheryomushki, where they began to work on the line Cheryomushki - Sayano-Shushenskaya HPP. In Leningrad, double-sided cars were used in passenger traffic in the late 80s and early 90s, later they began to be used for transporting work fleets and by tugboats.
In 1988, the production of LM-68M was discontinued due to the serial production of articulated cars LVS-86. A total of 2108 LM-68M single-sided cars were produced. Of these, 15 units were delivered to Arkhangelsk, 13 to Temirtau, 3 to Gorky and 3 to Cherepovets. On the basis of the LM-68M, a large number of different special-purpose cars were produced: rail grinding cars, catenary tower cars, sand carriers and others.
Technical details
Tram car type LM-68M is designed to carry passengers on city tram tracks and is designed for operation both as single cars and as part of two cars with multi-unit control.
The tram car is four-axle, has an all-metal body with a steel welded frame and a frame sheathed with steel sheets 2 mm thick. On the inside, the frame and sheathing sheets are protected from corrosion and covered with noise-absorbing mastic. Laminated plastic was used for the interior wall and ceiling cladding; the floor is made of plywood and topped with a corrugated rubber mat. The passenger compartment has two rows of soft seats: on the one hand - single, on the other - double, and three ticket offices. In the driver's cab, separated from the passenger compartment by a partition, all the car control equipment is concentrated. The door to the cab is sliding. The car has three screen-type entrance doors (the first and third are 1330 mm wide, the middle one is 1700 mm, since 1980 the third door is 1750 mm wide) with an electro-pneumatic drive and automatic opening from the driver's cab. Car lighting - 24 lamps with incandescent lamps, heating - with air from starting and braking resistances and electric furnaces with heating elements of the TEN type; ventilation is natural. The car is radio-equipped, sound and light signaling is provided.
On the LM-68M type car, four series-parallel excitation traction motors of the DK-259G7 type (later DK-259G3) were used, which are sprung and suspended on a bogie from the transverse beams. The gearbox is two-stage. The electric motor is powered by direct current with a voltage of 550 V from the contact network through a pantograph-type current collector. The car is equipped with a power multi-stage cam controller of the EKG-33B type, which has 17 positions. The car is controlled by a driver's cam controller KV-42G with 10 positions of the main handle: 4 running M, X1-X3, 5 brake T1-T4 and TR and zero position. The control circuit is powered by an iron-nickel storage battery, consisting of 20 ZhN-100 type cells with a rated voltage of 24 V; Along with the storage battery, a G-731A type generator with a DK-661A engine is installed. The car is equipped with high-speed current protection devices, special relays to protect the electrical circuit from being turned on in the event of a lack or insufficient voltage, as well as lightning arresters. The cockpit is equipped with an OM-23B type traction motor group switch. The car is equipped with electrodynamic, mechanical and electromagnetic rail brakes. The pneumatically actuated mechanical brake is activated when exhausted (for re-braking) or when the electrodynamic service brake fails.
The car body rests on the bogies by means of pads. Carts - bridge type, do not have a pronounced frame. Conventionally, the frame is formed by two casings of gearboxes, in which the axles of the wheel pairs are located, and two longitudinal welded beams of rectangular section. Feet are welded to the beams for fastening to the gearbox casings. The central suspension of the body is made in the form of double coil springs and rubber-metal elements. Wheelsets have rubber bandages with two rubber-metal disks.
The pneumatic equipment of the car is used as a drive for the lever-brake system, for opening and closing doors, lowering the undercar grid, giving sound signals, for controlling the reverser PR-759V, windshield wipers and sandboxes. The pneumatic system is divided into high pressure and low pressure lines. The air system is powered by an EK-4 type compressor.
Specifications
List of printed sources used
1. M.Ya. Reznik, B.M. Fists "Tram car LM-68", M .: Transport, 19772. M.D. Ivanov, A.P. Alpatkin, B.K. Hieropolsky "Arrangement and operation of the tram", M .: "Higher School", 1977
3. Nomenclature catalog PO Dynamo, M., 1991
4. V. Valdin "Tram of St. Petersburg 1860-2000" (electronic encyclopedia)
LM-68M tramcars were operated in Saint Petersburg, Arkhangelsk, Magnitogorsk, Nizhny Novgorod, Temirtau, Cherepovets.
StoryIn September 2017, the last original LM-68Ms were suspended from work with passengers. Technical details
Car LM-68M No. 7582 The tram car is four-axle, has an all-metal body with a steel welded frame and a frame sheathed with steel sheets 2 mm thick. On the inside, the frame and sheathing sheets are protected from corrosion and covered with noise-absorbing mastic. Laminated plastic was used for the interior wall and ceiling cladding; the floor is made of plywood and topped with a corrugated rubber mat. The passenger compartment has two rows of soft seats: on the one hand - single, on the other - double, and three ticket offices. In the driver's cab, separated from the passenger compartment by a partition, all the car control equipment is concentrated. The door to the cab is sliding. The car has three screen-type entrance doors (the first and third are 1330 mm wide, the middle one is 1700 mm, since 1980 the third door is 1750 mm wide) with an electro-pneumatic drive and automatic opening from the driver's cab. Car lighting - 24 lamps with incandescent lamps, heating - with air from starting and braking resistances and electric furnaces with tubular heating elements (heating elements); ventilation is natural. On the LM-68M type car, four series-parallel excitation traction motors of the DK-259G7 type (later DK-259G3) were used, which are sprung and suspended on a bogie from the transverse beams. The gearbox is two-stage. The car is equipped with a power multi-stage cam controller of the EKG-33B type, which has 17 positions. The car is controlled by a driver's cam controller KV-42G with 10 positions of the main handle: 4 running M, X1-X3, 5 brake T1-T4 and TR and zero position. The control circuit is powered by an iron-nickel storage battery, consisting of 20 ZhN-100 type cells with a rated voltage of 24 V; Along with the storage battery, a G-731A type generator with a DK-661A engine is installed. The car is provided with high-speed current protection devices, relays to protect the electrical circuit from being turned on in the event of a lack or insufficient voltage, as well as lightning arresters. The switch of groups of traction motors of type OM-23B is installed in the cab. The car is equipped with electrodynamic, mechanical and electromagnetic rail brakes. A pneumatically actuated mechanical brake is activated when the electrodynamic braking is depleted (for re-braking) or when the service electrodynamic brake fails. The car body rests on two bridge-type bogies. The central suspension of the body is made in the form of double coil springs and rubber-metal elements. Wheelsets have rubber bandages with two rubber-metal disks. The pneumatic equipment of the car is used as a drive for the lever-brake system, for opening and closing doors, lowering the undercar grid, giving sound signals, for controlling the reverser PR-759V, windshield wipers and sandboxes. The pneumatic system is divided into high pressure and low pressure lines. The air system is powered by an EK-4 type compressor. Modifications
Training car No. 5711
Tram PR with tail number 3613 overhauled
LM-68M "Training"A one-sided training car, originally built like this at VARZ (PTMZ). The differences from a conventional line car are as follows:
The training car with tail number 1740 was modernized according to the LM-68M2 project, and is now a passenger car. The car with tail number 3700 was painted according to the "green elephant" scheme during technical repairs and equipped with electronic route indicators (EMU).  71-88This is a double-sided, two-cabin version of the LM-68M. They are operated in Cheryomushki (Sayano-Shushenskaya HPP) and in St. Petersburg. From 1988 to 1992, 13 such cars were built. The cars received a second cab in the rear. There are two doors on both sides. Two pantographs are installed on the roof, part of the electrical equipment is located in the cabin in a cabinet behind one of the driver's cabs. 6 such cars were sent for operation to the village of Cheryomushki. In Leningrad, and later in St. Petersburg, double-sided cars were used in passenger traffic during repairs, but they were mainly used for transporting work parks and tugboats. In November-December 2015, a major overhaul of cars 71-88 (modifications 23M, car No. 3613 - 18M) No. 1703, 1704, 5705, 7124 and 3609 was carried out. handrails, flooring, lighting and seats, route indicators and an autoinformer system were added. Later, all the cars were transferred to the tram depot No. 3. On March 16, 2016, car No. 3609 entered route 40. Prior to this, cars 71-88 (in particular, No. 2125) were operated in passenger traffic only during the repair of tracks in the Primorsky District along the route "Baikonurskaya Street - Shavrova Street", on Nauki Avenue in 2001, on Vasilyevsky Island in 2005-2006. The cars are operated in tram depot No. 3 (No. 3609 - 3614). Car 2125 is a museum car. ETCTrack repair two-cabin cars based on LM-68M, similar in design to cars 71-88, but have an average door on only one of the sides, are operated as a night transportation, tug and welding. About 30 wagons were built. Currently, 10 cars are in operation in St. Petersburg, one of them (No. 3613) passed the CWR with a tie-in door missing for passenger operation.
PR car No. 3613 passed the Kyrgyz Republic. Former service. |
Lecture material for conducting classes with students of training groups for training tram drivers.
Topic No. 1. FUNDAMENTALS OF MECHANICS. BASIC CONCEPTS.
All bodies in nature are either at rest or in motion. A body that is at rest cannot come out of this state on its own.
movement called the movement of a body in space relative to other fixed bodies surrounding it. Movement can be translational, when the body moves, and rotational, when the body, while remaining in place, moves around its axis. The same bodies can have both translational and rotational motion at the same time, a good example is the motion of a tram car wheelset.
Depending on the speed, the movement may be uniform and uneven. In uniform motion, the body moves with the same speed in any period of time. The speed of uniform movement is calculated by the formula: v=s/t , Where v- movement speed;
S- the path traveled by the body;
t- time.
With uneven movement, the speed of the body changes, it either increases or decreases. Therefore, with uneven movement, it is necessary to know the average speed. The average speed of uneven motion is the speed with which a body could cover a given distance in the same period of time, moving uniformly. The formula for average speed is the quotient of the distance traveled divided by the time taken to travel it:
Vav. = s/t
acceleration is the increase in speed per unit of time. For example, if the train traveled 1 m in the first second, 2 meters in the second, and 3 m in the third, then this means that the train has a uniformly accelerated movement with an acceleration equal to 1 m / s. in a square. From what has been said, it can be seen that the magnitude of the acceleration can be calculated by the formula:
a \u003d v-vo / t (m / s squared).
If the body increases the speed and acceleration - the value is positive, the movement is called uniformly accelerated, and if the body reduces the speed and acceleration - the value is negative (ie deceleration), the movement is called uniformly slowed down.
In order to bring the body out of rest and make it move, it is necessary to apply some external force to it. In particular, in order to start a tram train, it is necessary to have a traction force.
By force called any cause that causes changes in the state of rest or movement of the body. Force is a vector quantity. This means that it has both magnitude and direction. The driver, driving a tram car, is faced with various forces acting on the car: these are traction and braking forces, friction and impact forces, gravity and centrifugal force.
Forces acting on the same body in the same straight line in the same direction are algebraically added. Therefore, the resultant will be equal to the algebraic sum of all forces.
If the forces act at an angle to each other, then the resultant of all forces will be equal to the diagonal of the parallelogram.
The movement of the body can continue even after the termination of the action of the force causing this movement. Thus, after turning off the traction motors and stopping the traction force, the tram car continues to move until it stops under the influence of the resistance force and braking forces. Such a phenomenon is called inertia.
by inertia called the property of bodies to maintain a state of rest or rectilinear uniform motion. This definition allows us to understand the basic law of inertia: every body tends to maintain the state in which it is located. The phenomenon of inertia must be taken into account in daily work on the line:
If the driver brakes the tram car abruptly, then the passengers in the passenger compartment will fall forward, as they seek to maintain the state of motion, and, conversely, when the car starts abruptly, standing passengers may fall back, as they seek to maintain a state of rest;
· in case of inept management of a tram car and entry into a curve at a speed higher than the permissible one, the car may derail, as it seeks to maintain rectilinear movement;
Improper braking in conditions of the axle box state of the track can lead to the formation of rolled wheelsets;
· the maximum use of the possibility to move in the run-out mode (by inertia) saves electricity;
· acceleration of the tram car before the rise will allow using the force of inertia to overcome the rise.
But not all bodies have the same inertia, the inertia of a body is characterized by its mass.
body weight called the amount of matter of which the body is composed. Mass is always proportional to body weight. Numerically, the mass of a body is equal to the ratio of the force acting on the body to the acceleration of the body caused by this force:
It takes to move the body JOB, equal to the product of the applied force times the path. However, only that force (or component of the force) that has a direction in the direction of motion is taken into account:
The unit of measurement of work is a kilogrammeter, i.e. the work that must be done to lift a load of 1 kg to a height of 1 m. To lift a load of 10 kg to a height of 1 m, it is necessary to expend the same work as for lifting a load of 1 kg to a height of 10 m. In both cases, this is 10 kgm.
In technology, the concept is of great importance. POWER. POWER - is the work done per unit of time.
In the previous example, if the work of lifting a load of 10 kg to a height of 1 m was completed in 5 seconds, then the power of the lifting unit is 2 kgm / s.
In practice, it is customary to consider 1 horsepower (hp) as a larger unit of power, at which work is done in one second to lift 75 kg of cargo to a height of 1 meter, i.e. work 75 kgm.
Between electrical power, measured in kilowatts (kW) and power, measured in horsepower, there are the following relationships:
1 HP = 736 W. or 1 kW. = 1.36 HP
A body capable of doing work has energy. Work can be done at the expense of the energy contained in the body, as well as at the expense of energy supplied to it from an external source. If there is no influx of energy from the outside or the influx of energy is less than the consumption, then its amount decreases. If more energy is supplied to the body than it consumes, then the body will accumulate energy in itself.
There are the following types of energy: mechanical, thermal, electrical, chemical, radiant (light), etc. Let us dwell in more detail on mechanical energy.
Mechanical energy can be in the form of positional (potential) energy or motional (kinetic) energy. A raised stone has potential energy and can do some work at any moment. A falling stone, a moving tram car have kinetic energy, i.e. the energy of movement. Kinetic and potential energy can freely transform one into the other.
Kinetic energy is directly proportional to the mass (weight) of the moving body and the square of the speed. Therefore, if the speed of the body increases by 2 times, then the stock of kinetic energy increases by 4 times. Potential and kinetic energy, like work, is expressed in kilogram meters.
FRICTION AND LUBRICATION. There are movement resistance forces that act in the opposite direction to movement and slow it down. These forces include, in particular, friction force. When one body moves along the surface of another, due to the presence of irregularities on the contacting surfaces, they are cut or erased, for which part of the driving force is spent. The more irregularities, the greater the friction and the greater the force expended to overcome it.
In mechanics, there are two types of friction:
sliding friction - for example, the friction of a brake shoe against a mechanical brake drum;
Rolling friction - for example, the friction of a rolling ball against the surface, or the friction of a wheel when a tram car moves against a rail head. Rolling friction is much less than sliding friction.
Friction is a harmful resistance, but in many cases it is useful and necessary. If there were no friction, then the wheels of the tram car would rotate in one place, without setting it in motion, since there would be no adhesion of the wheels to the rails.
Used to reduce frictional wear LUBRICATION. In practice, depending on the lubricant, one has to deal with various types of friction: dry, semi-dry, liquid and semi-fluid.
Dry friction gives the greatest wear, since it completely lacks lubrication (brake pad friction on the brake drum of a mechanical brake).
Semi-dry friction also gives significant wear and occurs when the rubbing surfaces are not completely lubricated.
Fluid friction gives the least wear and occurs when the rubbing surfaces are completely lubricated.
semi-fluid friction gives much less wear than with semi-dry friction. It occurs when part of the lubricant is displaced and rubbing surfaces come into contact. On a tram car, this type of friction occurs when the gears (gears) and bearings are not sufficiently lubricated.
The use of lubrication of rubbing parts solves the following main tasks:
reduction of friction
cooling, i.e. heat dissipation and its uniform distribution in all details,
noise reduction,
protection of friction parts from corrosion and increase their service life.
A very important point is the correct choice of lubricants. The most widely used on tram cars are liquid mineral oils and thick greases: CIATIM - 201, autol, nigrol, compressor oil, grease, etc.
Train resistance - this is the sum of all external forces, or rather, the sum of the projections of all external forces on the direction of movement, acting against the movement of the train. In the traction mode, it is overcome by the traction force generated by the traction motors. In the braking mode, the resistance to the movement of the tram train is added to the braking force.
The resistance to the movement of the train is divided into BASIC and ADDITIONAL. TO main resistance include all types of resistance to train movement that occur on a straight horizontal section of the track when moving. TO additional resistance includes all the resistances that arise when the train overcomes the rise and when passing curved sections of the track.
BASIC RESISTANCE consists of:
track resistance caused by the rolling friction of the wheels on the rails and the friction of the flanges on the rails,
resistance from the elastic landing of the tracks,
resistance from impacts at the joints and roughnesses of the track,
internal resistance of the rolling stock itself, determined by friction in bearings and transmission mechanisms,
resistance from possible malfunctions on the rolling stock (strong compression of brake pads, seizure in axial bearings, etc.),
air resistance during the movement of the car.
Specific resistance to movement is the amount of resistance per ton of train weight. For a single car, the main specific resistance to movement is calculated by the formula:
w = 4.3 + 0.0036 times the square of the car's speed.
Specific slope resistance in kg/t. equal to the magnitude of the slope, expressed in thousandths of the distance. For example, if the slope I \u003d + 0.008, then the resistivity will be equal to 8 kg / t. The value of resistivity from the curve is calculated by the formula 425/R curve.
The movement of the train on the line is characterized by three main modes: traction, run-out and braking.
In traction mode traction electric motors of a tram car are powered by a contact network and convert electrical energy into mechanical work, which is spent on accelerating the movement of the car (with an increase in its speed), to overcome resistance to movement, to overcome climbs, to fit into curves, and also to overcome the friction force .
Runaway mode traction motors are turned off, the train speed decreases (except for the movement on the descent, where the speed will increase) due to the fact that the kinetic energy of the train is spent on overcoming the resistance to movement.
In braking mode the speed of movement is reduced, if necessary, to zero due to the use of brake means that create forces that counteract the movement of the train.
General information about the cart.
Tram car bogies are designed for:
· For the perception of vertical loads from the mass of the body and passengers and their transmission to the wheel pairs;
· To distribute the load between the axles of wheel pairs;
· For the perception of the horizontal load that occurs during movement and its transfer from the body to the axles of the wheelsets;
· For transfer to a body of force of draft and braking;
· For guiding the axles of wheel pairs and ensuring that the car fits into curved sections of the track.
The car "LM-68M" is equipped with two swivel two-axle bogies of the bridge type with a conditional frame. Their use ensures smooth movement and smooth fitting of the car into curves. When the car is moving, the bogies are rotated relative to the body up to 15 degrees using a center plate installed on the pivot beam of the central spring suspension.
The main parameters of the trolley:
Track - 1524 mm.
· Diameter of new wheels on a circle of driving - 700 mm.
· The distance between the inner edges of the tires of wheel pairs - 1474 mm (plus - minus 2 mm).
· The maximum longitudinal dimension is 2640 mm.
· The maximum transverse dimension is 2200 mm.
· The weight of the trolley with TED is 4500 kg.
Trolley frame.
The bogie of a tram car by its design does not have a pronounced frame. The conditional frame of the bogie is formed by two longitudinal beams with paws welded to them at the ends, which rest on the necks of the long and short gearbox casings at the locations of the axial bearings. A ribbed rubber gasket is laid between the paws and the necks of the gearbox housings, which provides an elastic connection with the wheel pair and compensates for the diagonal deformation of the conditional frame when the bogie fits into curves. The rubber gasket also eliminates noise and vibration.
The longitudinal beam of the bogie is a welded box-section structure made of 12 mm thick steel. Cast steel paws are welded at the ends of the beam. The paws have rectangular ledges, which include ledges (fangs) of the gearbox housing with grease fittings screwed into them for lubricating spherical bearings. A bracket is welded to the beam for installing rubber buffers of the CRP and engine suspension, brackets for installing reinforced rubber buffers and TED suspension, a support bracket for installing an engine suspension shock absorber, a rail brake stop, a jet stop bracket, rail brake suspension brackets and an articulated rod bracket.
Mounted on the trolley:
· Two wheelsets with rubberized wheels;
· Four wheel covers;
· Four sand guides;
· Two two-stage reducer;
· Two traction motors;
· Two motor-suspended beams;
· Two cardan shafts;
· Two jet stops;
· Four motor grounding devices (ZUM), two on each gearbox;
· Two central drum brakes;
· Two rail brake shoes (BRT);
· Central spring suspension;
· Two articulated rods (earrings).
Axial boxes.
The axleboxes are designed to transfer the weight of the body, the conditional frame of the bogie, together with a part of the weight of the traction motors, to the axles of the wheel sets and to transfer the traction and braking force from the wheel set to the bogie of the tram car.
Depending on the design of the bogie, the axle of the wheel pair has necks for the axle box assembly either outside the wheel pair (with external axle boxes) or inside (with internal axle boxes). In the second case, wheel hubs are pressed at the ends of the axle. Modern bridge bogies have internal axle boxes.
Topic: SPRINGS AND SHOCK ABSORBERS.
Springs and shock absorbers are designed for:
Weakening of dynamic shocks and shocks that occur when the rolling stock moves along the rail track and is transmitted to its bogies and body,
creation of maximum smoothness of movement and damping of body vibrations, including sound frequency vibrations during the movement of the car,
· reduction of wear and tear of parts and components of rolling stock and tram tracks.
On rolling stock, depending on the type of wagon, the following are used:
1. sheet elliptical multi-row springs;
2. screw cylindrical (spring) springs.
The work of leaf elliptical multi-row springs is based on the principle of shock absorption due to the friction of the leaf springs against each other.
Helical cylindrical (spring) springs accumulate shock energy during compression.
On modern both passenger and special rolling stock, only helical cylindrical (spring) springs are used in such elements of mechanical equipment as:
1. central spring suspension ( PIU);
2. suspension of the motor suspension beam ( BCH);
3. suspension of rail brake shoes ( BRT).
Faults: fracture, wear, cracks.
shock absorbers
The following types of shock absorbers are used on tram rolling stock:
· rubber;
· hydraulic;
Rubber shock absorbers various forms are applied in the following elements:
· ring conic in TsRP;
· rubber stops between the pivot beam of the TsRP and the brackets of the longitudinal beams;
· gaskets between the paws of the longitudinal beams and the casing of the gearbox;
· rubber reinforced liners in wheel pairs;
barrel-shaped rubber shock absorbers in the MPB suspension;
in coupling devices;
· in reactive stops.
Hydraulic shock absorbers installed on the bogies of the LVS-86K car between the pivot beam of the TsRP and the longitudinal beam of the bogie, they work parallel to the TsRP to prevent significant lateral swing of the car.
Friction damper vibrations is installed on the LVS and LM-99 cars in addition to the springs in the suspension of the motor suspension beam.
Faults: destruction, drawdown, wear.
Reactive focus.
The reactive emphasis ensures the horizontal position of the neck of the gearbox housing. It consists of a leash hinged to the neck. The leash rests elastically through rubber shock absorbers on the longitudinal beam of the bogie. Reaction stops on the cart are located diagonally and are installed from the side of the short casings of the gearbox.
The horizontal position of the neck is achieved by adjustment. Deviation from the horizontal is allowed within +/- 10 mm.
Reactive thrust faults:
· Fracture of the jet stop leash;
· Settling or destruction of rubber shock absorbers;
· Opening on welding of a platform of a longitudinal beam;
· Fracture of the tide on the neck.
Hydraulic shock absorber.
One of the elements of connection between the body and the bogie on LVS-86K cars are hydraulic shock absorbers. They allow to reduce the vertical and lateral swing of the car, which significantly improves its driving performance.
The principle of operation of the hydraulic shock absorber is that as a result of the relative movement of the sprung and unsprung parts of the tram car (body and bogie), the fluid from one cavity of the shock absorber flows into another through calibrated holes, as a result of which the shock absorber resists vibrations. Spindle oil is used as a working fluid in the hydraulic shock absorbers on the LVS-86K car. The greatest force is created when the shock absorbers are in tension.
Rope block system.
The cable and block system consists of a steel cable with a diameter of 7.2 mm, stretched under the floor of the car and held by movable and fixed blocks. The cable is made up of four parts (sections), which end with chains (chains to the paired angular levers of the CBT) and are held by four blocks (three movable blocks and one fixed block). The first section of the cable connects the manual drive sector with the first movable block, the second and third sections connect the movable blocks, and the fourth section connects the movable block with a fixed block, which is the dead point of the cable-and-block system.
Parking brake faults:
wear of the teeth of the ratchet wheel;
breaks in springs
wear and tear of the cable;
slipping of the cable from the sector or from the holding block;
Sandboxes.
Sandboxes on a tram car are designed to supply sand to the rails in cases where it is necessary to artificially increase the coefficient of adhesion of the wheel to the rails. For sanding, the wagons are equipped with sandboxes, into which dry sand, which has good abrasive properties, is poured. The working mass of sand should be grains ranging in size from 0.1 to 2 mm.
On the car "LM-68M" in front of the first and third wheel sets, four air-driven slide sandboxes are installed. Sandboxes are installed inside the car on the floor under the passenger seats. The volume of sand of one sandbox is 13 liters, the mass of dry sand is 19.5 kg.
The sandbox consists of a box-reservoir for sand and a sandbox drive. The sandbox drive includes a pneumatic cylinder, the rod of which is mechanically connected to the drive gate. The box-reservoir has a metal hopper, one of the walls of which has an opening aligned with the opening of the drive, covered by the gate. The other drive hole of the sandbox is aligned with the flange built into the floor. The sand sleeve with an outer diameter of 58 mm and a length of 1200 mm is connected at one end to the flange shank, and at the other end is inserted into a guide mounted on a trolley.
Compressed air of high pressure, getting into the pneumatic cylinder, opens the gate and the sand by gravity along the sand sleeve gets to the rails. Sand supply rate - 400 grams in 5 seconds.
Sandbox issues:
lack of sand in the bunker;
· contamination and jamming of the gate;
high humidity of sand (damp sand);
Incorrect installation of the sand sleeve;
Subject: COUPLING DEVICES.
Coupling devices on the rolling stock of the tram are designed:
· to transfer traction from a motor car to a trailer car when towing tram cars;
· to mitigate the shocks and shocks transmitted by the wagons when decelerating;
· for the mechanical connection of two or three cars during the operation of the rolling stock according to the CME and compensation for the difference in tractive effort.
The coupling device of the LM-68M tram car is designed for a force of 10 tons. Two couplers are installed on the car frame under the front and rear platforms, each of which is connected to bifurcation on the wagon frame by means of roller and can turn around it when the car passes curved sections of the track. The coupling device consists of the following elements:
· rod of variable cylindrical section with thread on the shank;
shank nut with cotter pin;
buffer frame with a square hole;
· guide thrust washer, which is put on the rod and moves in the grooves of the buffer frame;
rubber shock absorber
· emergency buffer;
hitch;
pins (3 pieces);
Removable handshake-type coupling attachment;
Removable coupling device of the "Pipe" type.
The procedure for using coupling devices, coupling cars must be carried out in strict accordance with the "Instructions for Coupling and Towing Tram Cars", which is set out in Appendix No. 2 to the "Job Instruction for a St. Petersburg Tram Driver".
Clutch malfunctions:
· lack of cotter pin at the shank nut of the rod;
curvature of the rod, removable coupling nozzles, pins;
pin wear;
flaring holes on the rod;
Destruction of rubber shock absorber;
sagging hitch;
Removable nozzles are not worn on the rod.
MECHANICAL EQUIPMENT OF THE LM-68M TRAMWAY CAR.
