JP2011240891A - Air circuit for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a parking brake from being released until a state that the braking force of a service brake can be sufficiently secured is effected without using an air tank for a parking brake and the like.SOLUTION: Compressed air compressed by an air compressor 11 is introduced to a spring chamber 12 for parking brake through a working pressure conduit 13 and a relay valve 14 to release the parking brake, and the compressed air is introduced to a signal pressure chamber of the relay valve through a signal pressure conduit 16 and a manual control valve 17 for parking brake to open the relay valve. The signal pressure conduit is branched from and connected to a conduit between the air compressor and the relay valve out of the working pressure conduit, air tanks for service brake 23, 24 are provided in branch conduits 19, 21 branched from the signal pressure conduit between the air compressor and the manual control valve for parking brake, and a protection valve 31 for signal pressure air is provided in the signal pressure conduit on the air compressor side of the manual control valve for parking brake.

Description

  The present invention relates to an air circuit of a vehicle equipped with a parking brake spring chamber controlled by compressed air.

  Conventionally, as an air circuit for this type of vehicle, the parking brake is released by introducing the operating pressure air from the parking brake air tank to the parking brake spring chamber via a relay valve, and the parking brake manual control from the parking brake air tank is performed. A spring brake device configured to open a relay valve by introducing signal pressure air to the relay valve via a valve is disclosed (for example, see Patent Document 1). In this spring brake device, the signal brake air led from the service brake air tank is closed only under a condition where the signal pressure air led from the service brake air tank is below a predetermined pressure in the middle of the path leading the signal pressure air from the parking brake air tank to the parking brake manual control valve. A cut valve is provided. In addition, a check valve for preventing the backflow of the operating pressure air from the parking brake manual control valve side to the cut valve side is provided in the course of guiding the signal pressure air from the cut valve to the parking brake manual control valve.

  In the spring brake device configured as described above, when the vehicle is stopped in a state where the pressure in the service brake air tank drops below a predetermined pressure due to heavy use of the service brake, the signal pressure air introduced from the service brake air tank Since the cut valve closes when the pressure is less than the specified pressure, the signal pressure air from the parking brake air tank is not sent to the relay valve even if the parking brake lever is released and the parking brake manual control valve is opened. The parking brake spring chamber is maintained in an operating state until the pressure in the brake air tank is sufficiently recovered and the cut valve is opened. In other words, even if the parking brake spring chamber is released from a stopped state where the pressure in the service brake air tank is not sufficiently recovered, the parking brake spring chamber is prevented from being released, so reliable control by the service brake is prevented. The vehicle can be started only when power is available.

JP 2003-95083 A (claim 1, paragraph [0012], paragraph [0025])

  However, the conventional spring brake device disclosed in Patent Document 1 requires a relatively large number of parts such as a parking brake air tank, a cut valve, and a check valve, which makes the parts management troublesome. There was a problem that the assembly man-hours of the parts increased.

  The object of the present invention is to release the parking brake until the pressure of the service brake air tank rises to a pressure that can sufficiently secure the braking force of the service brake, without using the parking brake air tank or the cut valve. An object of the present invention is to provide a vehicle air circuit that can be prevented.

  As shown in FIGS. 1 and 2, the first aspect of the present invention is that the compressed air compressed by the air compressor 11 passes through the operating pressure line 13 and the relay valve 14 to the parking brake spring chamber 12 and is operated with the operating pressure air. As a result, the parking brake is released, and the compressed air compressed by the air compressor 11 passes through the signal pressure line 16 and the parking brake manual control valve 17 to the signal pressure chamber of the relay valve 14 as signal pressure air. In the vehicle air circuit configured to open the relay valve 14, the signal pressure line 16 is branched from the line between the air compressor 11 and the relay valve 14 in the working pressure line 13 and connected to the air compressor 11. Branch line 1 branched from the working pressure line 13 or the signal pressure line 16 between the parking brake manual control valve 17 , 21 are provided with service brake air tanks 23 and 24 for supplying compressed air to the service brake, and a signal pressure air protection valve 31 is provided in the signal pressure line 16 on the air compressor 11 side from the parking brake manual control valve 17. The signal pressure air protection valve 31 opens when the compressed air on the inlet 31d side of the signal pressure air protection valve 31 rises to a predetermined pressure, and the compressed air on the outlet 31e side of the signal pressure air protection valve 31 It is configured to close when the pressure falls to a predetermined pressure smaller than the predetermined pressure.

  The second aspect of the present invention is an invention based on the first aspect, and further, as shown in FIGS. 1 and 2, the air compressor 11 from the service brake air tanks 23 and 24 in the branch pipes 19 and 21. Service brake protection valves 33 and 34 are provided on the side, and the service brake protection valves 33 and 34 are provided when the compressed air on the inlets 33d and 34d side of the service brake protection valves 33 and 34 rises to a predetermined pressure. It is configured to open and close when the compressed air on the outlets 33e, 34e side of the service brake protection valves 33, 34 drops to a predetermined pressure lower than the predetermined pressure.

  The third aspect of the present invention is an invention based on the first or second aspect, and further, as shown in FIGS. 1 and 2, the branching portion of the signal pressure line 16 and the relay valve in the working pressure line 13. 14 is provided with an air tank 27, and a working pressure air protection valve 32 is provided in a pipe line between the air tank 27 and the relay valve 14 in the working pressure pipe 13. 32 is opened when the compressed air on the inlet 32d side of the working pressure air protection valve 32 rises to a predetermined pressure, and the compressed air on the outlet 32e side of the working pressure air protection valve 32 reaches a predetermined pressure smaller than the predetermined pressure. It is configured to close when lowered.

  In the air circuit of the first aspect of the present invention, the signal pressure line is branched and connected from the line between the air compressor and the relay valve in the working pressure line, and the air compressor and the parking brake manual control valve are connected. Service brake air tank is installed in the branch pressure line that branches from the working pressure line or signal pressure line, and the signal pressure air protection valve is installed in the signal pressure line on the air compressor side from the parking brake manual control valve. The parking brake can be prevented from being released until the pressure of the brake air tank rises to a pressure that can sufficiently secure the braking force of the service brake.

  That is, when the pressure of the service brake air tank is equal to or lower than the predetermined pressure, the signal pressure air protection valve is kept closed even if an operation to release the parking brake manual control valve is performed. Compressed air is not supplied to the signal pressure chamber. As a result, since compressed air is not supplied to the parking brake spring chamber, the parking brake is not released and the vehicle cannot travel. On the other hand, if the operation of releasing the parking brake manual control valve is performed in a state where the pressure of the service brake air tank is equal to or higher than the predetermined pressure, the signal pressure is increased by the pressure of the compressed air in the service brake air tank. Since the air protection valve is opened, compressed air in the service brake air tank having a predetermined pressure or higher is supplied to the signal pressure chamber of the relay valve. As a result, compressed air having a predetermined pressure or higher in the service brake air tank is supplied to the parking brake spring chamber through the relay valve, so that the parking brake is released and the vehicle can travel.

  Compared to conventional spring brake devices that require a relatively large number of parts such as parking brake air tanks, cut valves, and check valves, which complicates parts management and increases the number of parts to be assembled. Thus, in the present invention, it is not necessary to use an air tank for parking brake, a cut valve, or the like, so that parts management becomes easy and the number of assembling steps of parts can be reduced.

  In the air circuit of the second aspect of the present invention, since the service brake protection valve is provided on the air compressor side of the branch line from the service brake air tank, the service brake fails and air leakage occurs. Even if the pressure of the brake air tank rapidly decreases, it is possible to prevent the pressure of other air tanks from decreasing below a predetermined pressure.

  In the air circuit of the third aspect of the present invention, since the air tank is provided in the pipeline between the branch portion of the signal pressure pipeline and the relay valve in the working pressure pipeline, the capacity of the service brake air tank is reduced in the installation space. If the air tank capacity cannot be sufficiently secured, the tank capacity can be sufficiently secured by adding the air tank capacity to the service brake air tank capacity. In addition, since a protective valve for working pressure air is provided in the pipe between the air tank and the relay valve in the working pressure pipe, even if the parking brake fails and air leakage occurs, it is provided in the working pressure pipe. Further, it is possible to prevent the pressure of the air tank from dropping below a predetermined pressure.

It is an air circuit block diagram of the vehicle of this invention embodiment. It is a principal part expanded sectional view of each protection valve.

  Next, an embodiment for carrying out the present invention will be described with reference to the drawings. As shown in FIG. 1, an air circuit 10 is provided in a vehicle such as a truck. The air circuit 10 includes an air compressor 11 that compresses air, a parking brake spring chamber 12 that releases or operates a parking brake (not shown) by supplying and discharging compressed air, an air compressor 11, and a spring chamber 12. Between the air compressor 11 and the relay valve 14, one end of the working pressure line 13 being provided in the working pressure line 13, a relay valve 14 provided in the working pressure line 13 and having a signal pressure chamber (not shown). A signal pressure line 16 branched from the line between them and the other end communicating with the signal pressure chamber of the relay valve 14, and the pressure of the compressed air is adjusted by the driver operating in the signal pressure line 16. And a parking brake manual control valve 17 that can be supplied to the signal pressure chamber of the relay valve 14. The compressed air of a predetermined pressure compressed by the air compressor 11 is guided to the parking brake spring chamber 12 as the operating pressure air through the operating pressure line 13 and the relay valve 14 so that the parking brake is released. The The compressed air of a predetermined pressure compressed by the air compressor 11 is guided as signal pressure air from the signal pressure air inlet 14a of the relay valve 14 to the signal pressure chamber through the signal pressure line 16 and the parking brake manual control valve 17. Thus, the relay valve 14 is configured to open.

  An air dryer 18 is provided in a line between the air compressor 11 and the branch part of the signal pressure line 16 in the working pressure line 13. The air compressor 11 is driven by an engine (not shown), and the air dryer 18 is configured to adsorb moisture contained in the compressed air with a desiccant (not shown) to dry the compressed air. A front service brake branch pipe 19 branched from the signal pressure pipe 16 is connected to the signal pressure pipe 16 between the air compressor 11 and the parking brake manual control valve 17, and this front service brake branch pipe is connected. 19 is connected to a front service brake (not shown). The signal pressure line 16 between the air compressor 11 and the parking brake manual control valve 17 is connected to a rear service brake branch line 21 that branches from the signal pressure line 16. The branch pipe 21 is connected to a rear service brake (not shown). Further, an auxiliary machine branch pipe 22 branched from the signal pressure pipe 16 is connected to the signal pressure pipe 16 between the air compressor 11 and the parking brake manual control valve 17. Are connected to auxiliary devices (not shown) such as a clutch, an air horn, an air suspension, and an exhaust brake.

  The front service brake branch pipe 19 is provided with a front service brake air tank 23 for supplying compressed air to the front service brake, and the rear service brake branch pipe 21 is compressed to the rear service brake. A rear service brake air tank 24 for supplying air is provided. Further, the auxiliary branch pipe 22 is provided with an auxiliary air tank 26 for supplying compressed air to the auxiliary machine. Further, an air tank 27 is provided in the working pressure line 13 between the branch portion of the signal pressure line 16 and the relay valve 14. The air tank 27 cannot sufficiently secure the capacities of the front service brake air tank 23 and the rear service brake air tank 24 due to the installation space thereof, and the capacity of the air tank 27 is reduced to the front service brake air tank 23 and the rear service brake. By adding to the capacity of the brake air tank 24, it is provided to ensure a sufficient tank capacity.

  A signal pressure air protection valve 31 is provided on the signal pressure line 16 closer to the air compressor 11 than the parking brake manual control valve 17, and is provided on the line between the air tank 27 and the relay valve 14 in the working pressure line 13. Is provided with a protective valve 32 for working pressure air. Further, a front service brake protection valve 33 is provided on the front service brake branch pipe 19 on the signal pressure line 16 side from the front service brake air tank 23, and on the signal pressure line 16 side from the rear service brake air tank 24. A rear service brake protective valve 34 is provided in the branch pipe 21 for the rear service brake. Further, an auxiliary machine protection valve 35 is provided on the auxiliary machine branch pipe line 22 on the signal pressure pipe line 16 side from the auxiliary machine air tank 26. The signal pressure protection valve 31, the front service brake protection valve 33, the rear service brake protection valve 34, and the accessory protection valve 35 constitute a multi-protection valve 40, and the operating pressure air protection valve 32 provides a single protection. A valve 50 is configured.

  The signal pressure protection valve 31, the working pressure air protection valve 32, the front service brake protection valve 33, the rear service brake protection valve 34, and the accessory protection valve 35 are configured identically. As shown in detail in FIG. 2, these protective valves 31 to 35 include valve bodies 31 a to 35 a with flat bottom surfaces, valve seats 31 b to 35 b that are smaller than the bottom surfaces of the valve bodies 31 a to 35 a, and valve bodies 31 a to 31 a. And compression coil springs 31c to 35c that press the valve seats 31b to 35b with a predetermined force. The inlets 31d to 35d of the protective valves 31 to 35 are formed in the center of the valve seats 31b to 35b, and the outlets 31e to 35e of the protective valves 31 to 35 are formed on the outer peripheral surfaces of the valve seats 31b to 35b. Reference numerals 31f to 35f in FIG. 2 are seal members (O-rings).

  The signal pressure air protection valve 31 opens when the compressed air on the inlet 31d side of the signal pressure air protection valve 31 rises to a predetermined pressure (for example, 0.6 MPa), and the outlet of the signal pressure air protection valve 31. The compressed air on the 31e side is configured to close when the pressure decreases to a predetermined pressure (for example, 0.5 MPa) smaller than the predetermined pressure (for example, 0.6 MPa). The working pressure air protection valve 32 opens when the compressed air on the inlet 32d side of the working pressure air protection valve 32 rises to a predetermined pressure (for example, 0.6 MPa), and the outlet of the working pressure air protection valve 32. The compressed air on the 32e side is configured to close when the pressure decreases to a predetermined pressure (for example, 0.5 MPa) smaller than the predetermined pressure (for example, 0.6 MPa). The front service brake protection valve 33 opens when the compressed air on the inlet 33d side of the front service brake protection valve 33 rises to a predetermined pressure (for example, 0.6 MPa), and the front service brake protection valve 33 It is configured to close when the compressed air on the outlet 33e side is reduced to a predetermined pressure (for example, 0.5 MPa) smaller than the predetermined pressure (for example, 0.6 MPa). The rear service brake protection valve 34 opens when the compressed air on the inlet 34d side of the rear service brake protection valve 34 rises to a predetermined pressure (for example, 0.6 MPa), and the rear service brake protection valve 34 It is configured to close when the compressed air on the outlet 34e side of 34 drops to a predetermined pressure (for example, 0.5 MPa) smaller than the predetermined pressure (for example, 0.6 MPa). Further, the accessory protection valve 35 opens when the compressed air on the inlet 35d side of the accessory protection valve 35 rises to a predetermined pressure (for example, 0.6 MPa), and on the outlet 35e side of the accessory protection valve 35. The compressed air is closed when the pressure is reduced to a predetermined pressure (for example, 0.5 MPa) smaller than the predetermined pressure (for example, 0.6 MPa).

  By configuring each of the protective valves 31 to 35 as described above, for example, even if the front service brake fails and an air leak occurs and the pressure of the front service brake air tank 23 suddenly drops, another air tank The pressure of 24, 26, 27 can be prevented from dropping below a predetermined pressure. In addition, the code | symbol 36 in FIG. 1 is a check valve. The check valve 36 allows the flow of compressed air from the working pressure air protection valve 32 toward the relay valve 14 and blocks the flow of compressed air from the relay valve 14 toward the working pressure air protection valve 32. Composed.

  The operation of the air circuit 10 of the vehicle such as a truck configured as described above will be described. When the engine is started after the vehicle is left for a long time without starting the engine in the state where the parking brake is operated by pulling the operation lever 17a of the parking brake manual control valve 17, the air tank 27 and the front service brake are used. Since the pressure of the air tank 23, the rear service brake air tank 24, and the auxiliary air tank 26 is equal to or lower than a predetermined pressure (for example, 0.5 MPa), the operation lever 17a of the parking brake manual control valve 17 is returned to the parking brake. Even if the operation for releasing is performed, the signal pressure air protection valve 16 is kept closed, so that compressed air is not supplied to the signal pressure chamber of the relay valve 14. As a result, since compressed air is not supplied to the parking brake spring chamber 12, the parking brake is not released and the vehicle cannot travel.

  On the other hand, the air compressor 11 is driven by the engine, and compressed air is supplied to the air tank 27, the front service brake air tank 23, the rear service brake air tank 24, and the auxiliary air tank 26, and the pressure of each air tank is set to a predetermined pressure (for example, When the operation of releasing the parking brake manual control valve 17 is performed in the state of 0.6 MPa or higher, the signal pressure air protection valve 31 is opened by the pressure of the compressed air in the air tank 27. Compressed air having a predetermined pressure (for example, 0.6 MPa) or more is supplied to the signal pressure chamber of the relay valve 14. As a result, compressed air of a predetermined pressure (for example, 0.6 MPa) or more in the air tank 27 is supplied to the parking brake spring chamber 12 through the relay valve 14, so that the parking brake is released and the vehicle can travel.

  If the front service brake air tank 23 and the rear service brake air tank 24 have sufficient capacity, the air tank 27 may not be provided in the working pressure line 13. In this case, the air compressor 11 is driven by the engine, and compressed air is supplied to the front service brake air tank 23, the rear service brake air tank 24, and the auxiliary air tank 26, and the pressure of each air tank is set to a predetermined pressure (for example, 0. 0). 6MP) When the operation for releasing the parking brake manual control valve 17 is performed, the pressure of the compressed air in the front service brake air tank 23, the rear service brake air tank 24, or the auxiliary air tank 26 Since the signal pressure air protection valve 31 is opened at this time, the compressed air in the front service brake air tank 23, the rear service brake air tank 24, or the auxiliary air tank 26 has a pressure equal to or higher than a predetermined pressure (for example, 0.6 MPa). Is supplied to the signal pressure chamber. As a result, compressed air of a predetermined pressure (for example, 0.6 MPa) or more in the front service brake air tank 23, the rear service brake air tank 24, or the auxiliary air tank 26 passes through the relay valve 14 to the parking brake spring chamber 12. Since it is supplied, the parking brake is released and the vehicle can run.

DESCRIPTION OF SYMBOLS 10 Air circuit 11 Air compressor 12 Parking brake spring chamber 13 Working pressure line 14 Relay valve 16 Signal pressure line 17 Parking brake manual control valve 19 Front service brake branch line 21 Rear service brake branch line 23 Front service Brake Air Tank 24 Rear Service Brake Air Tank 27 Air Tank 31 Signal Pressure Air Protection Valve 32 Operating Pressure Air Protection Valve 33 Front Service Brake Protection Valve 34 Rear Service Brake Protection Valve 31d-34d Protection Valve Inlet 31e- 34d Protection valve outlet

Claims (3)

The parking brake is released by introducing the compressed air compressed by the air compressor (11) through the operating pressure line (13) and the relay valve (14) to the parking brake spring chamber (12) as operating pressure air, By introducing the compressed air compressed by the air compressor (11) as signal pressure air to the signal pressure chamber of the relay valve (14) through the signal pressure line (16) and the parking brake manual control valve (17). In the vehicle air circuit configured to open the relay valve (14),
The signal pressure line (16) is branched and connected from the line between the air compressor (11) and the relay valve (14) in the working pressure line (13),
Service brake to the branch line (19, 21) branched from the working pressure line (13) or the signal pressure line (16) between the air compressor (11) and the parking brake manual control valve (17) Service brake air tanks (23, 24) for supplying compressed air to
A signal pressure air protection valve (31) is provided in the signal pressure line (16) on the air compressor (11) side from the parking brake manual control valve (17),
The signal pressure air protection valve (31) opens when the compressed air on the inlet (31d) side of the signal pressure air protection valve (31) rises to a predetermined pressure and the signal pressure air protection valve (31). An air circuit for a vehicle, wherein the air circuit is configured to close when the compressed air on the outlet (31e) side of the vehicle drops to a predetermined pressure lower than the predetermined pressure. Service brake protection valves (33, 34) are provided on the air compressor (11) side of the service brake air tank (23, 24) in the branch pipe (19, 21),
The service brake protection valve (33, 34) opens when the compressed air on the inlet (33d, 34d) side of the service brake protection valve (33, 34) rises to a predetermined pressure and the service brake protection valve 2. The vehicle air circuit according to claim 1, wherein the air circuit is configured to close when the compressed air on the outlet side (33 e, 34 e) side of (33, 34) drops to a predetermined pressure smaller than the predetermined pressure. An air tank (27) is provided in a pipe line between the branch part of the signal pressure pipe line (16) and the relay valve (14) in the working pressure pipe line (13),
A working pressure air protection valve (32) is provided in a line between the air tank (27) and the relay valve (14) in the working pressure pipe (13),
The working pressure air protection valve (32) opens when the compressed air on the inlet (32d) side of the working pressure air protection valve (32) rises to a predetermined pressure and the working pressure air protection valve (32). The vehicle air circuit according to claim 1 or 2, wherein the air circuit is configured to be closed when the compressed air on the outlet (32e) side of the vehicle is reduced to a predetermined pressure smaller than the predetermined pressure.

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