The pneumatic part of the brake equipment (Fig. 1) includes a brake line (air duct) b with a diameter of 32 mm with end valves 4 of a valve or spherical type and connecting inter-car sleeves 3; a two-chamber tank 7 connected to the brake line b by a drain pipe with a diameter of 19 mm through an uncoupling valve 9 and a dust collector - tee 8 (faucet 9 has been installed in tee 5 since 1974); spare tank 11; brake cylinder 1; air distributor No. 483 m with main 12 and main 13 parts (blocks); auto mode No. 265 A-000; stopcock 5 with handle removed.
Auto mode is used to automatically change the air pressure in the brake cylinder depending on the degree of loading of the car - the higher it is, the greater the pressure in the brake cylinder. If there is an auto mode on the car, the handle of the load mode switch of the air distributor is removed after the mode switch of the air distributor is set to the loaded mode with cast-iron brake pads and the average mode with composite brake pads. Refrigerated wagons do not have auto mode. The reserve tank has a volume of 78 liters for four-axle wagons with a brake cylinder with a diameter of 356 mm and 135 liters for an eight-axle wagon with a brake cylinder with a diameter of 400 mm.
The charging of the tank 7, the spool and working chambers of the air distributor of the reserve tank 11 is carried out from the brake line 6 with the disconnect valve 9 open. In this case, the brake cylinder is connected to the atmosphere through the main part of the air distributor and auto mode 2. When braking, the pressure in the brake line is reduced through the driver's valve and partially through the air distributor, which, when activated, disconnects the brake cylinder 1 from the atmosphere and communicates it with the reserve tank 11 until the pressure in them is equalized during full service braking.
Brake lever transmission of freight cars is made with one-sided pressing brake pads(except for six-axle cars, in which the middle wheel pair in the bogie has a double-sided pressure) and one brake cylinder, bolted to the center beam of the car frame. Currently, on a pilot basis, some eight-axle tanks without a center beam are equipped with two brake cylinders, from each of which the force is transmitted only to one four-axle tank bogie. This is done to simplify the design, facilitate the brake linkage, reduce power losses in it and increase work efficiency. brake system.
The brake linkage of all freight cars is adapted to use cast iron or composite brake pads. Currently, all freight cars have composite pads. If it is necessary to switch from one type of pad to another, it is only necessary to change the gear ratio of the brake linkage by rearranging the tightening rollers and horizontal levers (into a hole closer to the brake cylinder with composite pads and, vice versa, with cast iron pads). The change in the gear ratio is due to the fact that the friction coefficient of the composite pad is approximately 1.5-1.6 times greater than that of cast iron standard pads.
In the brake linkage of a four-axle freight car (Fig. 2), horizontal levers 4 and 10 are pivotally connected to rod b and bracket 7 on the rear cover of the brake cylinder, as well as to rod 2 and auto-regulator 3 and to rod 77. They are connected to each other by tightening 5 , holes 8 of which are designed for installing rollers with composite pads, and holes 9 - with cast-iron brake pads.
The brake lever transmission of an eight-axle car (Fig. 3, a) is basically similar to the transmission of a four-axle car, the only difference is the presence of a parallel transmission of force to both four-axle bogies on each side through the rod 1 and balancer 2, as well as the upper arm of the vertical arms shortened by 100 mm leverage.
In the lever transmission of a six-axle car (Fig. 3.5), the transfer of force from the brake cylinder to the triangels in each bogie does not occur in parallel, but in series.
Passenger carriages. Air distributor No. 292 and electric air distributor No. 305 are installed on the working chamber 11, which is mounted on the bracket of the rear cover of the brake cylinder. Under the car there is also a main pipe 1 1/4 ″, end valves 2 with connecting sleeves 1 and heads, a tee-dust collector 8. The brake line is connected by a branch 9 through a disconnect valve 10 with an air distributor block (Fig. 2.5).
Each passenger car has at least three stop valves 4, two of which are located in the car vestibules. The 78L reserve tank is connected by a 1″ pipe to the brake cylinder rear cover bracket. An exhaust valve 15 is installed on the pipe from the reserve tank or on the reserve tank.
Rice. 2.5. Brake equipment passenger car
1 - connecting sleeve R17B with connecting head No. 369A, 2 - end valve No. 190, 3 - two-pipe junction box No. 316, 4 - stop valve No. 163, 5 - three-pipe junction box, 6 - conduit, 7 - insulated suspension, 8 - tee-dust collector, 9 - outlet, 10 - disconnect valve No. 372, 11 - working chamber, 15 - exhaust valve No. 31, VR - air distributor No. 292, EVR - electric air distributor No. 305, TC - brake cylinder 14 "No. 501B, ZR - spare tank 78l
The working and control wires of the electro-pneumatic brake are laid in a steel pipe 6 and connected to the end two-pipe 3 and the middle three-pipe 5 boxes. From the middle box, the wire in a metal pipe goes to the working chamber of the electric air distributor, and from the end boxes to the contacts in the connecting head of the intercarriage hose.
When charging and releasing the brake, air from the line through the air distributor enters the reserve tank, and the brake cylinder is connected to the atmosphere through the air distributor. When braking, the air distributor is activated, disconnects the brake cylinder from the atmosphere and communicates it with the reserve tank. At full braking, the pressure values in the reserve tank and the brake cylinder equalize.
Freight wagons. The two-chamber tank 7 is attached to the frame of the car with four bolts and connected by pipes to the tee-dust collector 5, a spare tank with a volume of 78 liters and a 14″ brake cylinder through auto mode. The main 9 and the main 6 parts of the air distributor are attached to the two-chamber tank (Fig. 2.6).
Disconnect valve 8 is installed in the dust collector tee 5 in front of outlet 10 and is used to turn off the air distributor.
End valves 2 and connecting sleeves 1 are located on the main air duct. End valves are installed with a rotation of 60 ° relative to the horizontal axis. This improves the operation of the hoses in curved sections of the track and eliminates the impact of the heads of the hoses when following hump retarders and turnouts.
Stop cock 3 with the handle removed is installed only on wagons with a brake platform.
Rice. 2.6. Freight car brake equipment
1 - R17B connecting sleeve, 2 - end valve No. 190, 3 - stop valve No. 163, 4 - brake line, 5 - dust collector tee, 6 - main part, 7 - two-chamber tank No. 295, 8 - uncoupling valve No. 372 , 9 - main part, 10 - branch, AR - auto mode No. 265, VR - air distributor No. 483, TC - brake cylinder 14 "No. 188B, ZR - spare tank 78l
When charging and releasing the brake, compressed air from the brake line enters the two-chamber tank and fills the reserve tank, main, spool and working chambers of the air distributor. The brake cylinder communicates with the atmosphere through the auto mode and the main part of the air distributor. When the pressure in the line decreases, the air distributor informs the reserve reservoir with the brake cylinder. On cars without auto mode, the pressure in the brake cylinder is set by the manual switch of the air distributor braking modes, depending on the car load and the type of blocks. On cars with auto mode, the braking mode switch is set to medium mode with composite pads and to loaded mode with cast iron pads, and its handle is removed.
High-speed passenger cars. The high-speed car is equipped with pneumatic, electro-pneumatic, disc, magnetic rail and hand brakes (Fig. 2.7).
Feeding PM and brake TM lines are laid along the entire car, ending in connecting sleeves 18 with end valves 4, as well as line 2, which is designed to connect additional air consumers to electro-pneumatic doors and a vacuum-type toilet (through uncoupling valve 3). Four stop valves 1 are installed on the brake line, and the TM connecting sleeves are equipped with universal heads and fixed on insulated hangers. Working and control electric wires electropneumatic brakes are laid in a steel pipe and connected to the end two-pipe and middle three-pipe terminal boxes. From the middle terminal box 17 there is a working wire outlet to the EVR electric air distributor.
The car is equipped with a VR air distributor, an electric air distributor, three pressure switches RD1, RD2, RD3, pneumatic cylinders ПЦ1-ПЦ8 of a magnetic rail brake, brake cylinders ТЦ1-ТЦ8 with built-in rod output regulators, an anti-skid device (includes impulse sensors, reset valves 10 and a central the electronic unit), a spare tank ZR with a volume of 55 l, as well as a RU control tank with a volume of 100 l and two feed tanks PR1, PR2 with a volume of 170 and 78 liters, respectively. Each of the air tanks is equipped with drain cocks.
The switchgear control reservoir is filled with compressed air from the supply line through the disconnect valve 19, throttle Dr1 with a diameter of 2.5 mm and check valve KO1. Charging of the nutrient reservoirs PR1, PR2 is carried out from the brake line through the uncoupling valve 14, the three-way valve 11 and the throttle Dr2 with a diameter of 2.5 mm: the reservoir PR1 - through the uncoupling valve 12 and the check valve KO2; tank PR2 - through the uncoupling valve 13 and the check valve KO3. From the reservoir PR1, compressed air passes to the pressure switch RD1 and RD2 through which the filling of the brake cylinders ТЦ1-ТЦ8 is carried out, and from the reservoir PR2 to the pressure switch РД3, which controls the filling of the pneumatic cylinders ПЦ1-ПЦ8 of the magnetic rail brake.
The spare tank ZR is charged from the TM brake line through the disconnect valve 5 and the air distributor.
Rice. 2.7. Brake equipment of a high-speed passenger car
1 - stop valve No. 163, 2 - line of additional air consumers, 3 - uncoupling valve No. 372, 5 - uncoupling valve No. 377; 9, 12-16, 19 - disconnection valves No. 379, 4 - end valve No. 4304, VR - air distributor No. 292, EVR - electric air distributor No. 305, 8 - exhaust valve No. 4310, 10 - relief valve, 11 - three-way valve No. E -220, 17 - terminal box, 18 - connecting sleeve No. R17B; МН1, МН2 - manometers; RD1-RD3 - pressure switch No. 404; pressure alarms No. 115; Dr1, Dr2 - throttles 2.5mm, KO1-KO3 - check valves, LTC - "false" brake cylinder 12l, ZR - spare tank 55l, RU - control tank 100l; PR1, PR2 - nutrient tanks with a volume of 170l and 78l, respectively
During pneumatic (or electro-pneumatic) braking, an air distributor or an electric air distributor is activated, which communicates the ZR with the control chambers of the pressure switch RD1, RD2. The pressure switches, in turn, act on braking and pass compressed air from the supply tank PR1 into the brake cylinders ТЦ1-ТЦ8 of both bogies.
An anti-skid device is used to protect the wheel pairs of each bogie from jamming (skidding). In the presence of skidding, the axial sensor of the anti-skid device sends a signal to the corresponding relief valve 10, which disconnects the PR1 supply reservoir from the brake cylinders and simultaneously releases compressed air from the TC of this wheel pair (or wheel pairs of one or both bogies), thereby reducing the amount of pressure on the brake overlays. After reducing the pressure in the TC and equalizing the speeds of the wheel pairs, the relief valve again communicates the reservoir PR1 (through the pressure switch) with the brake cylinders and the braking process continues with the same efficiency. Pressure alarms D3-D6 are installed on the pipelines between the relief valve 10 and the brake cylinders of each wheel pair, signaling the operation of the anti-skid device.
Service braking of the car is carried out only by a disc brake. The magnetic rail brake is used only for emergency braking and acts in conjunction with the disc brake. The duration of the magnetic rail brake is not more than five minutes.
An additional tank is installed on the pipeline between the BP and the pressure switch, with a volume of 12 liters - a “false” LTC brake cylinder and a pressure indicator D2. The presence of a false brake cylinder artificially increases the volume of the control chambers of the pressure switch, which in turn provides a certain limiting pressure that is set in the brake cylinders when the brake line is properly discharged during pneumatic braking or when braking with an electro-pneumatic brake.
The pressure signaling device D2 is used to obtain information about the presence or absence of pressure in the shopping center. In the presence of compressed air in the shopping center, the signaling device closes its contacts in the electrical power circuit of the signal lamps, which are installed on the car frame (one on each side of the car) and in the service room.
When the brake is released, VR or EVR release air into the atmosphere from the control chambers of the pressure switch RD1, RD2, which, in turn, empty the brake cylinders ТЦ1-ТЦ8 into the atmosphere.
An exhaust valve 8 is installed on the pipeline between the ZR and the air distributor, which is designed to release the brake manually. The leashes from the valve 8 are brought to both sides and inside the car (into the passenger compartment).
The operation of the magnetic rail brake is carried out as follows: when the brake line is discharged at the rate of emergency braking, the pressure indicator D1 is turned on, located on the outlet TM between the uncoupling valve 14 and the three-way valve 11. At the same time, the EPV electro-pneumatic valve receives power, which begins to pass compressed air from the supply air through the F3 filter. tank PR2 into the control chamber of the pressure switch RD3. The pressure switch RD3 works as a repeater and informs the tank PR2 with pneumatic cylinders PC1-PC8 of lowering the shoes of the magnetic rail brake.
To turn off the brake system of the car, it is necessary to close the disconnect valve 5 to the air distributor 6 and the disconnect valve 14 to the supply tanks PR1, PR2.
Passenger car with KE-GPR brake. Passenger carriage of international traffic of Russian railways equipped with a KE-GPR brake with an air distributor 4 and a tank 5 with a volume of 9 liters (Fig. 2.8).
Rice. 2.8. Brake equipment of a passenger car with KE-GPR brake
1 - axial sensor, 2 - safety valve, 3 - relief valve, 4 - KE S air distributor; 5, 9 - tanks with a volume of 9 l; 6, 7 - spare tanks, 8 - axial regulator, 10 - air filter, 11 - throttle. 12 - valve, 13 - pressure switch, 14 - handle for switching braking modes, 15 - handle for turning the brake on and off, 16 - leash, 17 - button for checking the auto mode, 18 - box with a pressure gauge and a button for checking the operation of the axial regulator, 19 - sensor, 20 - additional tank
Spare tanks of cars have volumes of 150 liters and are equipped with brake cylinders with a diameter of 16".
Each axle has an axial sensor 1 of the anti-skid device, a safety valve 2 in case of a hose break to the sensor 1 and a relief valve 3 for automatically releasing the wheels when skidding.
The car is equipped with a device for high-speed regulation, which consists of an axial regulator 8, a tank 9 with a volume of 9 liters, air filter 10 and throttles 11 with a hole of 2mm.
To check the operation of the axial regulator 8, there is a pressure gauge and a button in the box 18, and a pressure gauge in the service room. Regulator 8 at a speed of 90-100 km / h provides in the process of braking at high-speed mode PS (R), in the brake cylinders the pressure is 3.6-3.8 kgf / cm 2 (series 15 cars) or 3.8-4.0 kgf / cm 2 (cars of series 17 and 77), and at speeds below 90 km / h - respectively 1.6-1.8 or 2.1-2.3 kgf / cm 2, which is the maximum pressure in the cargo mode T (G) and passenger P (R). The brake line with a diameter of 1" is equipped with four connecting sleeves with end valves.
The brake is turned on and off with the handle 15, and manually released with the leash 16. The handle 14 is designed to switch between the PS, T and P modes. , two pressure switches 13, two additional tanks 20 with valves 12 for shutting down in case of a hose break to the sensor 19. and a button 17 for checking the auto mode.
Introduction
Auto brake technology is one of the most important elements of railway transport; the carrying capacity of roads and the safety of train traffic largely depend on the level of development and condition of this technology.
The braking equipment of the rolling stock must work normally under the conditions of complex processes occurring in a moving train (dry friction of brake shoes with the conversion of mechanical energy into heat, gas-dynamic processes in the brake line, rolling of wheels on rails under conditions of maximum use of adhesion forces, interaction of cars with each other with the appearance of significant longitudinal forces, etc.).
To ensure the uninterrupted operation of rolling stock auto-brake equipment in difficult meteorological conditions and with high traffic density, employees of auto-brake checkpoints and automatic departments of locomotive and car depots do a lot, constantly improving the technology of repairing brake equipment, ensuring high reliability and stability of its operation in trains.
In order to ensure the safe operation of the brake equipment, the following types of repair and inspection of the brake equipment of cars have been established: factory, depot, revision and current.
In modern operating conditions and in the near future, automation of maintenance of various components of the brake system, its adaptation to remote control with the driver and other devices.
Purpose and design of the brake linkage of a freight car
A lever brake transmission is a system of rods and levers, through which the human effort (during manual braking) or the force developed by compressed air is transmitted along the brake cylinder rod (during pneumatic and electro-pneumatic braking) to the brake pads, which are pressed against the wheels. According to the effect on the wheel, lever gears with one-sided and two-sided pressing of the pads are distinguished.
Lever brake gear with double-sided pressing of the pads has the following advantages compared to a single-sided one: the wheelset is subjected to an eversion action in the axle boxes in the direction of the pressing force of the pads; the pressure on each pad is less, therefore, the wear of the pads is less; the coefficient of friction between the block and the wheel is greater. However, leverage with double-sided pressing is much more complicated in design and heavier than with one-sided, and the heating temperature of the pads during braking is 10-15% higher. With the use of composite pads, the disadvantages of one-sided pressing become less noticeable due to less pressure on each pad and a higher coefficient of friction.
Basically, all freight cars have one-sided pressing of the pads, and passenger cars have two-sided, with vertical levers located on both sides of the wheels. Therefore, triangels are used on freight cars, and beams (traverses) on passenger cars.
The device of the brake linkage of a four-axle freight car is shown in Figure 1.
Figure 1 - The device of the brake linkage of a four-axle freight car
The piston rod 6 of the brake cylinder and the dead center bracket 7 are connected by rollers with horizontal levers 10 and 4, which are interconnected in the middle part by a puff 5. Puff 5 is installed in holes 8 with composite shoes, and with cast-iron shoes in hole 9. From opposite ends levers 4 and 10 are articulated by rollers with a rod 11 and an auto-regulator 3. The lower ends of the vertical levers 1 and 14 are connected to each other by a spacer 15, and the upper ends of the levers 1 are connected to the rods 2, the upper ends of the extreme vertical levers 14 are fixed to the cart frames with the help of earrings 13 and brackets. Triangels 17, on which shoes 12 with brake shoes are installed, are connected by rollers 18 with vertical levers 1 and 14.
To prevent the triangles and spacers from falling onto the track in case of their separation or breakage, safety angles 19 and brackets are provided. Brake shoes and triangles 17 are suspended from the bogie frame on suspensions 16. The traction rod of the regulator 3 is connected to the lower end of the left horizontal lever 4, and the adjusting screw is connected to the rod 2. When braking, the body of the regulator 3 rests against the lever connected to the horizontal lever 4 by tightening .
A similar linkage, differing only in the size of the horizontal levers, have gondola cars, platforms, tanks, etc.
The action of the lever transmission of a four-axle car is similar to the action of the lever transmission discussed above. For manual adjustment of the linkage in the rods 2, earrings 13 and puffs 15 there are spare holes.
The hand brake drive is connected by means of a rod to the horizontal lever 4 at the point of connection with the rod 6 of the brake cylinder, so the action of the leverage will be the same as during automatic braking, but the process is slower.
The most critical parts of the lever transmission of freight cars are triangles with a blind fit of brake shoes 3 (Figure 2).
brake lever car repair
Figure- 2 Triangel with a blind fit of the brake shoes
Bookmark 2 is installed with inside shoe. The tip 5 placed behind the shoe lies on the shelf of the side beam of the bogie in the event of a break in the suspension 4 and protects the triangle from falling onto the track. The parts mounted on the trunnions are fixed with slotted nuts 8 and fixed with cotter pins 9. The blocks 7 are fastened in the shoes with checks 6. The triangel is pivotally connected to the side beams of the bogie by means of hangers 4. All freight cars must have shoe hangers with rubber bushings in the holes (figure 3). This allows you to remove loads from the suspension that cause fatigue cracks, prevents breaks and parts from falling onto the track.
Figure-3 Suspension with rubber bushings in holes
To increase the reliability of the linkage and prevent the fall of puffs and rods, both strips 1 of each vertical and horizontal lever are welded together with strips 2. When placed in the holes of such levers, the connecting rollers are fastened as usual with a washer and cotter pin with a diameter of 8 mm.
The rods and horizontal levers near the cylinder are equipped with safety and support brackets.
To improve the reliability of the linkage and prevent the fall of puffs and rods, both strips 1 of each vertical and horizontal lever are welded together with strips 2 (Figure 4). The connecting shafts, when inserted into the holes of such levers, are fastened as usual with a washer and a cotter pin with a diameter of 8 mm.
Figure 4 - Welded strips to improve the reliability of the linkage
Additionally, from the side of the roller head, a safety cotter pin of the same diameter is inserted into specially welded cheeks 3 to prevent the roller from falling out if the main cotter pin is lost.
Figure 5 - Cheeks to prevent the roller from falling out
The design feature of the linkage transmission of eight-axle cars is the presence of a balancer, which ensures the distribution braking force on both carts (Figure 6). Many freight cars are equipped with a hand or parking brake with a steering wheel located on the side of the car.
Figure 6 - Features of the design of the brake linkage of 8-axle cars
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Ministry of Railways of Russia
RUSSIAN STATE OPEN
TECHNICAL UNIVERSITY OF COMMUNICATIONS (RGOTUPS)
Test
discipline Fundamentals of technical diagnostics
"Brake equipment of freight cars"
Student Nesterov S.V.
Saratov - 2007
Brake equipment is used to reduce the speed of the car and stop it in a given place.
The most important parameter of the efficiency of the braking system is its braking coefficient or the length of the path that a car moving at a given speed will cover from the moment the braking starts to a complete stop. The design of the brake equipment is very diverse. However, if we consider it as an automated system, then we can select a number of blocks combined into a single block diagram (Fig. 1).
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Rice.1. Structuralschemebrakeequipment
The brake system works as follows. The control unit 1 ensures that the brake system is charged with compressed air through the brake line (link unit 2) and, if necessary, gives a signal to start braking or releasing. The control signal is received by the air distributor 3, which, using the auto mode 4, activates the brake cylinder 5 with a lever transmission and an automatic regulator 6. The force from the brake cylinder is transmitted to the friction pair 7, which ensures the absorption of the kinetic energy of motion, i.e. wagon braking. The braking process of the wheelset 9 is controlled and regulated by the anti-skid device 8. Therefore, the efficiency of the braking system is ensured by the high-quality functioning of all units. Moreover, the predominantly serial connection of blocks makes such a system very vulnerable, since the failure of one of the blocks leads to the failure of the entire system. This feature of the operation of braking equipment requires a clear organization of the system for diagnosing and Maintenance.
Functional diagnostics of the effectiveness of the automatic brakes is carried out during the movement of the train (after departure to the station) mainly on a flat straight section of the track at a speed of 40-60 km/h. To do this, the driver performs trial braking of the train, usually by reducing the pressure in the brake line by 0.03-0.04 MPa. If a sufficient braking effect is not obtained within 20-30 seconds in freight trains, then emergency braking is performed and other measures are taken to stop the train, since the brakes do not function correctly. Experienced drivers can determine the braking coefficient by the train deceleration rate.
For example, in the United States, the following system for diagnosing train brake systems began to be applied on an experimental basis. On the last car of the train and in the driver's cab, electronic units with microprocessors are installed, which interact with each other via radio communication. According to the corresponding program, pressure and leaks from the brake line in the head and tail of the train, the process of braking and release are monitored. At the request of the driver, this information is displayed on the display located in the driver's cab.
In the wagon industry at maintenance points, quasi-functional diagnostics of brake equipment by structural parameters is widely used, which is called full and reduced testing of brakes. The essence of testing is as follows.
After charging the brake network of the train to the set pressure, the tightness of the air line is checked. To do this, for example, in freight trains, the driver's crane is set to the position II and measure the time of pressure drop in the main tanks with the compressors off by 0.05 MPa. The time rate is set depending on the volume of the main tanks and the length of the train in the axes.
After checking the tightness of the train line, the brakes are monitored. To do this, the stage of braking is performed by reducing the pressure in the line by 0.06-0.07 MPa and the handle of the driver's crane is set to the position of shutting off with power. All air distributors of the train must act on braking and not spontaneously release during the entire time of the test. The control of the action of the brakes is carried out by the inspectors of the cars, who, according to the structural diagnostic parameters, evaluate the technical condition of the brake equipment. The diagnostic parameters in this case are: the output of the brake cylinder rod, the pressing of the pads to the wheels, the correct location of the gear levers, the absence of intense air leaks in the elements of the brake equipment. If it is established that the brake system has worked normally for braking, then a signal is given to release the brakes and the driver's crane is moved to the position II. The release of the brakes is monitored. The correctness of the release is checked by the return of the rods to the cylinders, the departure of the brake pads from the wheels, the absence of intense leaks, in that case from the air distributors.
Rice. 2. Schemepointscentralizedtestingbrakes
At the end full testing brakes fill out a certificate of brakes form VU-45. At large PTOs, there are centralized testing points for diagnosing brakes (Fig. 2). Two point schemes have become widespread. In Scheme A, all diagnostic equipment is located in the room of the checkpoint, and pipelines with end valves 1, 2, 3, 4 are connected to the Pit to connect the brake network of the trains and a two-way loudspeaker. The testing of the train brakes is controlled by the operator of the centralized point, who performs it according to the algorithm described above.
In Scheme B, autonomous semi-automatic devices 5, 6, 7, 8 are installed at each intertrack for diagnosing automatic brakes according to the corresponding program. The compressed air supply and cable lines are centralized, through which the diagnostic results are recorded on the equipment of point B. The point operator actually controls the actions of semiautomatic devices and car inspectors, and also decides on the volume repair work and maintain appropriate records. As can be seen from the described procedure for the complete testing of the brakes, this process is quite lengthy, which makes it difficult to service trains, especially long trains, and increases their downtime at the maintenance station. To reduce the process of diagnosing brakes, VNIIZhT researchers have proposed two methods. The essence of the first method is that it is recommended to control the density of the line by measuring the flow of compressed air in the process of charging the brake network. Indeed, as operating experience shows, air leaks in the composition are concentrated mainly in places where end valves, connecting sleeves, tees, dust collectors, couplings are located. Therefore, the state of the brake line is essentially characterized by a transit flow caused by leaks concentrated in the indicated places. Therefore, by measuring the air flow when charging the brake network, you can first observe high flow, going to charge spare tanks, and then gradual stabilization of compressed air consumption. This stabilized level of air flow actually goes to replenish the leaks. Evaluating it depending on the length of the train, it is possible to determine whether the density of the brake line meets the established standards.
The second way is that the tightness of the brake line is checked after the braking stage. In this case, the wagon air distributors are activated and disconnected from the brake line. Therefore, if 15-20 seconds after braking, leaks are checked, they will characterize the density of the brake line of the train. This means that in this case it is also possible to combine two procedures for testing the brakes and reduce the time of the entire diagnostic cycle.
With reduced testing of the brakes, the diagnostic algorithm is greatly simplified. After charging the brake network, a braking stage is performed and the operation of the brakes of only the tail cars is controlled. If the brakes of the tail cars have worked, then the brakes are released and the quality of the release of the brakes of the tail cars is controlled. Consequently, with a reduced test of autobrakes, the actual integrity and serviceability of the brake line of the train and, with a certain probability, the operation of all brakes are checked when the brakes of the tail cars are activated.
Air distributors and auto modes
The method for diagnosing air distributors can be considered using the example of testing freight car devices. On the test stand, four parameters of the functioning of the main part of the air distributor and three parameters of the main part are controlled.
Moreover, tests of the diagnosed, for example, main part are carried out together with the reference main part of the same type of air distributor. Subsets used as references must comply in all respects with the requirements of the manufacturer's instructions. When testing, the operation of the main part is checked in a flat loaded mode according to the following parameters: charging time of the spool chamber; softness of action; the clarity of functioning at the degree of braking and vacation. The main part of the air distributor is checked in the mountain empty and loaded modes. In this case, the main attention is paid to the control of the charging time of the reserve tank, the correct operation of the non-return supply valve, filling and dispensing of the brake cylinder (time and pressure). At present, a test bench with automatic program control of the StVRG-PU type is being introduced at auto-brake checkpoints (St - stand, VRG - cargo air distributors, PU - with program control).
The stand works as follows. The test and reference parts of the air distributor are installed on the counter flanges of the stand and fixed with pneumatic clamps. The stand is charged and the software control unit is turned on. The step searchers of the program block, which are in the initial position, turn on the corresponding electro-pneumatic measuring instruments and start testing the air distributor according to the unconditional diagnostic algorithm. Electrocontact pressure gauges measure the pressure in the tanks and air distributor chambers, and time interval counters record the time (in seconds) of filling or emptying the tanks. The memory block also remembers the information and stores it until the end of the check.
If at any stage of diagnostics the measured parameters go beyond the established norms, then the tests automatically stop and the red signal lamp lights up. The indication block indicates on which operation a defect was detected. This allows you to quickly determine which air distributor assembly is faulty.
freight car braking equipment
auto modes.
Diagnosis of auto modes is carried out on the stand (Fig. 3). The stand consists of a pneumatic clamp, in which auto mode 1 is set and connected to tank 6 and through valve 2 to tank 3. Reducer 4, receiving power from compressed air line 7, maintains the specified pressure in tank 3. In turn, the tank 6 is equipped with a valve 5 with a calibrated hole. Imitation of the operation of auto mode 1 at different loadings of the car is carried out by cylinder 9 using crane 8.
Rice. 3. Schemeboothfordiagnosingauto modes.
Diagnosis of auto mode is performed in the following sequence. First, the reducer 4 sets the pressure in the tank 3 to 0.3 - + 0.005 MPa, i.e. tank 3 will simulate the operation of the car brake air distributor. Auto mode 1 is set to work in empty mode, i.e. with a gap between the head and the cylinder rod 9 in the released state d? 1 mm. Valve 2 is opened, and compressed air from reservoir 3 through auto mode 1 enters reservoir 6, which plays the role of a brake cylinder. In the brake reservoir 6, a pressure of 0.125 - 0.135 MPa should be established. This concludes the first stage of testing. At the second stage, valve 2 is closed, and compressed air is released from tank 6 into the atmosphere. Cylinder 9 is supplied with compressed air from line 7 by means of valve 8. Cylinder 9 is triggered and lowers the head of auto mode 1 by 24 - + 1 mm, i.e. switches it to medium mode. Next, the reducer 4 sets the initial pressure in the tank 3, open the valve 2 and measure the pressure in the brake tank 6, which should be 0.3 MPa. The time of movement of the damper piston of the auto mode down when air is released from the cylinder 9 should be within 13-25 seconds. In the same order, the operation of the auto mode is controlled at other loadings of the car, as well as when simulating a leak from the brake cylinder by opening a calibrated hole in the valve 5 of the tank 6.
Leverage auto-adjusters
The effectiveness of the brake system depends largely on the correct operation of the brake cylinder and linkage. The output of the rod of the brake cylinder must be within the limits provided for by the instructions of the MPS. An increase in the output of the rod in excess of the established norm leads to a decrease in the efficiency of the brake, since the pressure in the brake cylinder will be lower than the calculated value. Small rod extensions with non-direct acting brakes cause an overpressure in the brake cylinder, which can cause wheel seizure.
The output of the brake cylinder rod depends not only on the wear of the brake pads, but also on the correct adjustment of the linkage and its rigidity. The brake linkage must be adjusted so that, when braked, the horizontal levers occupy a position close to the perpendicular rod of the brake cylinder and rods. The vertical arms on the bogie should have approximately the same slope, and the suspension and chocks would form approximately a right angle between the suspension axle and the direction of the radius of the wheel passing through the center of the lower suspension pivot.
The rigidity of the transmission should not be below the norm. For example, on a freight car with a brake cylinder with a diameter of 14 and gear ratio n rp = 11.3 rod outlet in empty mode is 110 mm, in medium mode - ? 120 mm, and loaded -? 135 mm. To ensure automatic control of the linkage, auto-regulators are used, for example, 536 M, 574 B, and a pneumatic regulator RB 3. The leverage regulators are checked on the stand (Fig. 4). The stand consists of a brake cylinder 1 connected to a lever transmission, consisting of a horizontal lever 2, a tested regulator 4, a limiter 3, a simulator of the elasticity of the brake gear 5, a vertical lever 6 with a brake shoe, a wheel simulator 7 with an adjusting screw 8. Brake cylinder rod output 1 is measured by the device 9. By adjusting the position of the wheel simulator 7 with the screw 8, it is possible to reduce the gap between the wheel and the block. Therefore, the stand simulates the operation of a lever transmission on a car. The regulator is tested on the stand according to the algorithm.
Rice. 4. Schemeboothfordiagnosingautoregulatorslevertransmission.
From the beginning, set the regulator to its original position, i.e. when the linkage is adjusted correctly and the regulator should not act on either the dissolution or the contraction of the gear. In this position, the dimension a from the protective tube to the control mark on the screw shank must be between 75 and 125 mm. After that, the positional stability of the regulator is checked. For this, a longitudinal line is applied with chalk on the pipe and the thrust of the regulator screw and a number of successive braking cycles - vacation are simulated on the stand. For a working regulator, the protective tube in this position should not rotate relative to the screw, i.e. the size of a should not change. Next, check the action of the regulator for dissolution. To do this, by turning the control pipe, screw the regulator nut onto the screw by 1-2 turns and thereby reduce the size a. The braking process is simulated on the stand and the regulator must restore the initial size a, and during subsequent braking it should not change. At the next stage, the action of the regulator for contraction is checked. To do this, the adjusting nut is turned 1-2 turns to increase the dimension a, i.e. "dissolve" the transfer. After each braking, the dimension a must decrease, which is observed on the chalk line "measured by the device" marked on the protective tube and rod.
Anti-skid devices
The main function of these devices is to prevent jamming of wheel sets during braking. The anti-skid device consists of an axial sensor mounted on the axle box of the wheelset; a safety valve located on the car body and connected to the axial sensor by a flexible hose; exhaust valve located next to the brake cylinder. The devices work as follows. The axle sensor, when the wheelset is jammed, sends a signal to the safety valve, which acts as an amplifier and actuates the exhaust valve. Through the exhaust valve, the compressed air from the brake cylinder is released into the atmosphere and the brake is released for a short time. As soon as the speed of the wheelset is restored, the braking process resumes, and so on.
Three types of anti-skid devices have been used on wagons: inertial type, improved for international wagons, and electronic. Anti-skid devices of the inertial type are triggered when the rotational movement of the wheel tread is slowed down by 3-4 mm per second. Included with advanced anti-skid device type MWX includes 4 axial sensors MWX2, two actuating valves MWA15 and four safety valves. Thus, the devices control the speed of rotation of all four wheelsets of the car.
The set of electronic anti-skid device includes an electronic unit, four tachogenerators installed on each axle of the wheelset, and four resetting electro-pneumatic valves.
Rice. 5. schemeboothfordiagnosingantiskiddevices.
Power is supplied from battery. Despite the design differences, all types of anti-skid devices actually have similar structural schemes and they are controlled on the stand (Fig. 5). The stand for checking the anti-skid device includes: base 1, on which the axle box 2 with the sensor 3 of the anti-skid device is fixed; brake shoe 4 with cylinder 6, which is mounted on frame 5; rotator 7 with V-belt transmission; relief valve 8; air distributor 9; brake line 10; spare tank 11; brake cylinder 12, and simulator 13 linkage, in the form of an elastic element. The diagnostic technique is as follows. The stand is turned on and with the help of the rotator 7 with V-belt transmission, the specified frequency of rotation of the axle neck of the wheelset with the flywheel is reproduced. Compressed air is supplied to the cylinder 6, which receives the brake shoe 4 to the flywheel. The braking process begins. The anti-skid test is carried out from the beginning under normal braking, i.e. deceleration of the wheelset speed less than 3 m/s 2 . In this case, the anti-skid device should not work. Next, the jamming of the wheelset is simulated, i.e. the process of stopping the flywheel occurs with a deceleration of more than 3-4 m/s 2 . In this case, the sensor 3 of the anti-skid device should work to turn off the brake system, turn on the relief valve 8, which connects the brake cylinder 12 to the atmosphere. The pressure is released from the cylinder 6 and the process of rotation of the wheelset axle is resumed. At this time, the valve 8 closes and the air distributor 9 connects the reserve tank 11 with the brake cylinder 12, simulating the braking process. Then, the operation of the anti-skid sensor 3 is reproduced again, and so on.
It should be noted that the described stand consists, as it were, of two parts: the first, which simulates the jamming of the wheelset and the operation of the sensor, and the second, which reproduces the operation of conventional elements of braking equipment - an air distributor, a spare tank, a brake cylinder and a lever transmission.
Diagnosis is carried out according to the parameters of the deceleration at which the sensor is triggered, the time of emptying and filling the brake cylinder, the flow of compressed air from the reserve tank during repeated operation of the anti-skid device, and others. The anti-skid device is adjusted so that it ensures the prevention of jamming of the wheelset with a minimum decrease in the braking efficiency of the entire system.
Magnetic rail brake
Such brakes are mainly used as additional brakes for emergency braking of high-speed trains. Electromagnetic shoes are located on both sides of the cart in the space between the wheels. Each such shoe, when the brake is released, is held above the rails by springs mounted in vertical pneumatic cylinders with guides. The shoes are also equipped with shock absorbers and cross links.
During emergency braking, compressed air is supplied to the cylinders that lower the shoes onto the rails, and at the same time, current from the batteries is supplied to the windings of the solenoids of the shoes. Electromagnets are attracted, and there is friction of the shoes on the rails, which ensures the braking of the cars.
Rice. 6. Schemeboothfordiagnosingmagnetic railbrakes.
Checking the efficiency of the magnetic rail brakes is carried out on the stand (Fig. 6). For testing, the magnetic rail brake unit 1 is mounted on rotating metal circles 2, which imitate a moving rail track, and fixed with ties 3 to fixed supports. Perform a series of cycles braking - release. Braking efficiency is measured by the power consumption of electric motors rotating circles 2. When checking, they also measure the response time of the shoes for braking and release, control the efficiency of the lifting devices, dampers and connections.
Occupational safety requirements for the repair of brake equipment of freight cars
1. Repair of brake equipment must be carried out in accordance with the repair and technological documentation, the requirements of the Instruction for the Repair of Brake Equipment of Cars by specially trained locksmiths under the supervision and guidance of a foreman or foreman.
2. Before changing air distributors, exhaust valves, parts of brake equipment, reservoirs, supply pipes to the air distributor, before opening the brake cylinders and adjusting the leverage, the air distributor must be turned off, and the air from the spare two-chamber reservoir must be released.
3. Contraction of the brake linkage, when adjusting it, should be done using a special tool. To align the holes in the heads of the rods and the levers of the brake linkage, it is necessary to use a barb and a hammer. It is forbidden to check the coincidence of the holes with your fingers.
4. When purging the brake line, in order to avoid hitting the connecting sleeve, hold it with your hand near the connecting head.
5. Before disconnecting the connecting sleeves, the end valves of adjacent cars must be closed.
6. To disassemble the piston after removing it from the brake cylinder, it is necessary to compress the spring with the brake cylinder cover so much that it is possible to knock out the rod head pin and remove the cover, gradually releasing it until the spring is fully decompressed.
7. Before separating the piston rod head of the brake cylinder and the horizontal arm, the air distributor must be turned off, and the air from the spare and two-chamber reservoir must be released. Removal and installation of the piston of the brake cylinder must be carried out using a special tool.
8. Before changing the end valve, it is necessary to disconnect the brake line of the freight car from the power source.
9. When repairing brake equipment under a freight car, it is forbidden to be at the head of the piston rod of the brake cylinder on the side of the rod outlet and touch the head of the rod.
10. It is forbidden to tap the reservoirs of the working chamber and the air distributor during their cleaning, as well as to unscrew the plugs of brake devices and reservoirs under pressure.
11. Special installations and air columns for testing auto brakes and other purposes must be equipped with connecting heads. When testing auto brakes, it is forbidden to carry out repair work running gear frame, auto-brake device for brakes of freight cars.
12. When repairing equipment under a freight car, it is prohibited to sit on the rail.
Literature
1. Sokolov M.M. Wagon diagnostics.
2. Sergeev K.A., Gotaulin V.V. Fundamentals of technical diagnostics.
3. Birger I.A. Technical diagnostics. M: Mechanical engineering.
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for students of the specialty "Wagons"
in the discipline "Wagons (general course)"
to laboratory work No. 11
GENERAL DEVICE OF BRAKING EQUIPMENT
FREIGHT AND PASSENGER CARS
Irkutsk 2005
UDC 629.4.077
Compiled by: A.V. Pargachevsky, Art. teacher;
G.V. Efimova, Art. teacher;
M.N. Yakushkina, assistant
Department of Carriages and Carriage Facilities
Reviewers: P.A. Golets, head of the technical department of the railcar service of the Eastern Railway, a branch of Russian Railways;
candidate of technical sciences G.S. Pugachev, Associate Professor of the Department of Carriages and Carriage Economy.
Lab #11
GENERAL DEVICE OF BRAKING EQUIPMENT
FREIGHT AND PASSENGER CARS
Objective: To study: the general arrangement of the brake system of the car; location of the main devices of auto-brake equipment on freight and passenger cars; types of pneumatic brakes, their modes of braking.
Brief information from the theory
Brake equipment of wagons is designed to create and increase the resistance forces to a moving train. Forces that create artificial resistance are called braking forces.
Braking and resistance forces dampen the kinetic energy of a moving train. The most common means for obtaining braking forces is shoe brake, at which braking is carried out by pressing the pads to the rotating wheels, due to which there are friction forces between the block and the wheel.
On the rolling stock of railways, 5 types of brakes are used: parking (manual), pneumatic, electro-pneumatic, electric and magnetic rail.
Pneumatic brakes are used on freight cars of the general network of the Ministry of Railways. The pneumatic brake system includes: a brake line (M), which is located relative to the longitudinal axis of symmetry of the car (Fig. 1). The brake line is attached to the car body in several places and at the end beam of the car frame it has end valves, connecting sleeves with heads (Fig. 2). The brake line of each car included in the formed train must be connected to each other with the help of connecting sleeves, and the end valves are open. The end valve of the tail carriage of the train must be closed.
From the brake line on each car there are outlets through tees to the air distributor (VR) and, in some cases, to stop valves (Fig. 1). The air distributor (VR) and the spare tank (SR) are attached to the brackets mounted on the car frame with bolts. In the main types of cars, the air distributor and the reserve tank are located in the middle part of the frame. For some types of specialized freight cars, the air distributor and spare tank are installed in the cantilever part of the car frame.
The air distributor is connected to the brake line (M), the reserve tank and the brake cylinder by means of pipes (Fig. 3).
An uncoupling valve is installed on the pipe between the brake line (M) and the air distributor (VR), which must be closed in case of a faulty auto brake of the car - the valve handle is located across the pipe.
The brake cylinder is bolted to the brackets mounted on the car frame and connected to the air distributor using a pipe (Fig. 4).
When braking, the force from the rod of the brake cylinder (TC) is transmitted through the horizontal levers and the tightening of the horizontal levers to the rods connected to the brake linkage of the bogie.
On one of the links of the brake linkage, a rod output regulator is installed, which, as the brake pads wear out, reduces the length of this rod and thereby compensates for the increase in gaps between the pads and the wheel rolling surfaces.
A schematic diagram of the brake linkage of a two-axle freight car bogie is shown in fig. 5.
To secure a single-standing freight car from spontaneous departure, it has a parking (manual) brake, the main elements of which are shown in Fig. 6. A similar device has a parking brake for passenger cars. These brakes are operated manually by turning a handwheel or crank.
In addition to these units, the brake equipment of some types of freight cars has an auto mode - this is a device that provides automatic regulation of air pressure in the brake cylinder, depending on the load of the car. It is installed between the air distributor and the brake cylinder.
Some types of passenger cars are equipped with an anti-skid device that provides automatic pressure reduction in the brake cylinder to stop the wheelset from slipping when the car is in motion.