Brake air pressure control device, air pressure control method, and air pressure control program

Abstract

An air pressure control device comprising: an air pressure circuit configured to supply air to a brake mechanism that applies braking force to a wheel; and a control unit configured to control air pressure that is supplied from the air pressure circuit to the brake mechanism. The control unit is configured to decelerate a vehicle by supplying the air to the brake mechanism on the basis of a signal for urgently stopping the vehicle, and, when the vehicle reaches a speed equal to or lower than a predetermined speed, to reduce the air pressure that is supplied to the brake mechanism.

Description

[Technical field]

[0001] The present disclosure relates to an air pressure control device, an air pressure control method, and an air pressure control program. [Background technology]

[0002] Guidelines have been established for systems that respond to driver abnormalities, which stop the vehicle as an emergency measure when the driver is suddenly unable to continue driving safely due to a sudden change in the driver's physical condition, etc. (see, for example, Non-Patent Document 1). In addition, various brake systems and the like have been proposed in accordance with these guidelines. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Basic design document for driver abnormality response system (deceleration and stopping type), March 2016, Ministry of Land, Infrastructure, Transport and Tourism, Road Transport Bureau, Advanced Safety Vehicle Promotion Study Group Summary of the Invention [Problem to be solved by the invention]

[0004] In the above brake system, when the vehicle is brought to an emergency stop, it is required to stop the vehicle quickly but safely, i.e., it is required to reduce the load on the occupants when the vehicle is brought to an emergency stop.

[0005] An object of the present disclosure is to provide an air pressure control device, an air pressure control method, and an air pressure control program that can reduce the load on an occupant when a vehicle makes an emergency stop. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided an air pressure control device comprising an air pressure circuit configured to supply air to a brake mechanism that applies a braking force to a wheel, and a control unit configured to control the air pressure supplied from the air pressure circuit to the brake mechanism, the control unit configured to supply air to the brake mechanism to decelerate the vehicle based on a signal for bringing the vehicle to an emergency stop, and to reduce the air pressure supplied to the brake mechanism when the vehicle speed drops below a predetermined speed.

[0007] According to the above configuration, the braking force is weakened by reducing the air pressure supplied to the brake mechanism when the vehicle speed drops below a predetermined speed during deceleration, and the change in acceleration (jerk) at the moment the vehicle comes to a complete stop can be reduced, thereby reducing the load on the occupants when the vehicle makes an emergency stop.

[0008] In the above air pressure control device, the control unit may be configured to increase the reduced air pressure to a predetermined value or higher after a predetermined time has elapsed since the vehicle became equal to or less than the predetermined speed.

[0009] According to the above configuration, the vehicle is stopped a predetermined time after the vehicle speed drops below a predetermined speed, so that the braking force of the brake mechanism is increased by increasing the air pressure supplied to the brake mechanism above a predetermined value, thereby preventing the vehicle from moving from a stopped state.

[0010] With regard to the above air pressure control device, the control unit may be configured to increase the air pressure supplied to the brake mechanism to above a predetermined value after a predetermined time has elapsed since the air pressure became equal to or lower than a lower limit pressure due to the reduction in air pressure.

[0011] According to the above configuration, the vehicle is stopped a predetermined time after the pressure falls below the lower limit pressure, so by increasing the air pressure supplied to the brake mechanism to a predetermined value or above, the braking force of the brake mechanism is increased, and the vehicle can be prevented from moving from a stopped state.

[0012] With regard to the above air pressure control device, the control unit may be configured to keep the air pressure supplied to the brake mechanism constant at the upper limit pressure when the air pressure supplied to the brake mechanism becomes equal to or greater than an upper limit pressure during deceleration of the vehicle.

[0013] According to the above configuration, the braking force of the brake mechanism can be kept constant by making the air pressure supplied to the brake mechanism constant when the vehicle has decelerated to a certain extent during deceleration, thereby suppressing sudden changes in speed.

[0014] In the above air pressure control device, the control unit may be configured to determine the air pressure to be supplied to the brake mechanism at predetermined time intervals. According to the above configuration, the air pressure to be supplied to the brake mechanism is determined at predetermined time intervals, so the amount of calculation can be reduced compared to when the air pressure to be supplied to the brake mechanism is determined at any time.

[0015] In the above air pressure control device, the air pressure circuit may be configured to supply air to the brake mechanism in place of a brake valve that supplies air to the brake mechanism when a brake operation is performed.

[0016] According to the above configuration, normally, the brake valve supplies air to the brake mechanism when the driver operates the brakes, but in the event of an abnormality in the driver's condition, the control unit controls the air pressure circuit instead of the brake valve to supply air to the brake mechanism, thereby making it possible to bring the vehicle to an emergency stop.

[0017] In the above air pressure control device, the control unit may be configured to supply air pressure for gentle braking to the brake mechanism when it receives an abnormality signal indicating an abnormality due to the operation of a passenger switch as a signal for bringing the vehicle to an emergency stop. According to the above configuration, since the passenger would be surprised if sudden braking was performed immediately after the operation of the passenger switch, it is possible to call the passenger's attention by first causing the brake mechanism to perform gentle braking.

[0018] In the above-mentioned air pressure control device, the air pressure circuit may have a first port connected to an air tank of a vehicle, a second port connected to a brake valve that outputs an air pressure signal when a brake operation is performed, and a third port connected to a brake mechanism that applies a braking force to a wheel based on the air pressure signal, and is configured to switch between a first communication state in which air is supplied from the second port to the third port, and a second communication state in which air is supplied from the first port to the third port, and the control unit may be configured to switch the air pressure circuit from the first communication state to the second communication state based on a signal to make an emergency stop of the vehicle.

[0019] According to the above configuration, a first communication state in which the brake valve and the brake mechanism are connected and air is supplied from the second port to the third port is switched to a second communication state in which the air tank and the brake mechanism are connected and air is supplied from the first port to the third port. Therefore, air can be automatically supplied from the air tank to the brake mechanism to generate braking force.

[0020] According to one aspect of the present disclosure, there is provided an air pressure control method for an air pressure control device. The air pressure control device includes an air pressure circuit configured to supply air to a brake mechanism that applies a braking force to a wheel, and a control unit configured to control the air pressure supplied from the air pressure circuit to the brake mechanism. The air pressure control method includes a deceleration step of supplying air to the brake mechanism based on a signal for emergency stopping the vehicle to decelerate the vehicle, and an air pressure reduction step of reducing the air pressure supplied to the brake mechanism when the vehicle during the deceleration reaches a predetermined speed or less.

[0021] According to the above method, the braking force is weakened by reducing the air pressure supplied to the brake mechanism when the vehicle speed drops below a predetermined speed during deceleration, and the change in acceleration (jerk) at the moment the vehicle comes to a complete stop can be reduced, thereby reducing the load on the occupants when the vehicle makes an emergency stop.

[0022] According to one aspect of the present disclosure, there is provided an air pressure control program for an air pressure control device. The air pressure control device includes an air pressure circuit configured to supply air to a brake mechanism that applies a braking force to a wheel, and a control unit configured to control the air pressure supplied from the air pressure circuit to the brake mechanism. When the air pressure control program runs on a computer of the air pressure control device, it causes the air pressure control device to execute a deceleration step of supplying air to the brake mechanism to decelerate the vehicle based on a signal for emergency stopping the vehicle, and an air pressure reduction step of reducing the air pressure supplied to the brake mechanism when the vehicle during the deceleration reaches a predetermined speed or less.

[0023] According to the program, when the vehicle decelerates and reaches a predetermined speed or below, the air pressure supplied to the brake mechanism is reduced to weaken the braking force, thereby reducing the change in acceleration (jerk) at the moment the vehicle comes to a complete stop, thereby reducing the load on the occupants when the vehicle makes an emergency stop.

[0024] According to one aspect of the present disclosure, a non-transitory computer-readable medium storing an air pressure control program is provided, which, when executed in a computer of an air pressure control device including an air pressure circuit configured to supply air to a brake mechanism that applies a braking force to a wheel and a control unit configured to control the air pressure supplied from the air pressure circuit to the brake mechanism, causes the air pressure control device to supply air to the brake mechanism based on a signal for emergency stopping the vehicle to decelerate the vehicle, and to reduce the air pressure supplied to the brake mechanism when the vehicle during the deceleration reaches or falls below a predetermined speed. [Brief description of the drawings]

[0025] [Figure 1] 1 is a schematic diagram showing an overall configuration of a pneumatic brake system including an air pressure control device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a perspective view showing the appearance of the air pressure control device according to the embodiment. [Diagram 3] FIG. 2 is a schematic diagram of the abnormality response system according to the embodiment. [Figure 4] 4 is a circuit diagram of the pneumatic circuit of the embodiment, showing a first communication state in which a brake valve and a brake mechanism are communicated with each other. FIG. [Diagram 5] FIG. 4 is a circuit diagram of the pneumatic circuit of the embodiment, showing a second communication state in which the air tank and the brake mechanism are communicated with each other. [Figure 6] 4 is a flowchart showing a processing procedure of the abnormality response system according to the embodiment. [Figure 7] 5 is a graph showing a control example of the abnormality response system according to the embodiment. [Figure 8] 4 is a flowchart showing a processing procedure of the abnormality response system according to the embodiment. [Figure 9] 13 is a graph showing a modified example of the control example of the abnormality response system. [Figure 10] FIG. 11 is a schematic diagram showing a part of a pneumatic brake system including a pneumatic control device according to a modified example of the pneumatic control device. [Figure 11] FIG. 11 is a schematic diagram showing a part of a pneumatic brake system including a pneumatic control device according to a modified example of the pneumatic control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] An embodiment of an air pressure control device and an air pressure circuit provided in the air pressure control device will be described with reference to Figures 1 to 8. The air pressure control device is provided in a pneumatic brake system mounted on a vehicle such as a bus.

[0027] As shown in FIG. 1, a pneumatic brake system 11 mounted on a vehicle 10 is a full air brake system that pneumatically controls the command system of the brake mechanism and has an air-driven brake mechanism. The pneumatic brake system 11 is equipped with an air tank 12 that stores compressed air generated by a compressor (not shown). The air tank 12 has a first tank 12A, a second tank 12B, and a third tank 12C. For example, the first tank 12A is a tank that stores compressed air for applying a braking force to the front wheels of the vehicle 10. The second tank 12B is a tank that stores compressed air for applying a braking force to the rear wheels. The third tank 12C is a tank that stores compressed air used for other purposes. The first tank 12A and the second tank 12B are connected to a front pressure chamber 13A and a rear pressure chamber 13B of a brake valve 13. In addition, the first tank 12A and the second tank 12B are connected to an air horn device 14B via a protection valve 14A.

[0028] The brake valve 13 is also connected to a relay valve 15 via an air pipe 18. When a brake pedal 13C of the brake valve 13 is operated by the driver, an air pressure signal is output from the brake valve 13 to the relay valve 15. The relay valve 15 is also connected to an air tank 12 via an air pipe (not shown). When the relay valve 15 inputs an air pressure signal from the brake valve 13, a large amount of compressed air stored in the air tank 12 is supplied to the relay valve 15 via the air pipe. The large amount of compressed air supplied to the relay valve 15 is supplied to a brake chamber 17 via an ABS (Anti-lock Brake System) control valve 16. The brake chamber 17 generates a braking force on the wheels by the air being supplied to it. The ABS control valve 16 and the brake chamber 17 constitute an air pressure-driven brake mechanism.

[0029] When an emergency response system that stops the vehicle by the operation of a passenger other than the driver is installed in the pneumatic brake system 11 of a vehicle in use (existing vehicle), a pressure control module (PCM) 20 is provided in the middle of the air piping 18 of the command system that connects the brake valve 13 and the relay valve 15. The pressure control module 20 has a first port P1 that connects to the air tank 12 (third tank 12C), a second port P2 that connects to the brake valve 13, and a third port P3 that connects to the brake mechanism including the relay valve 15. The pressure control module 20 corresponds to an air pressure control device. Note that, since the pressure control module 20 is provided between the brake valve 13 and the relay valve 15, it can also be attached to a pneumatic brake system 11 that has a brake mechanism other than an air pressure-driven type.

[0030] Next, the configuration of the pressure control module 20, including its external appearance, will be described with reference to FIG. As shown in Fig. 2, the pressure control module 20 includes a case 210 that houses a control device and the like. The case 210 is formed of, for example, resin. A body 211 in which a flow path and the like are formed is connected to the case 210. The body 211 is formed by a casting method such as aluminum die casting. The body 211 is provided with a port connection section 212 that connects various ports. The port connection section 212 has a pair of second ports P2 provided on a first surface 213.

[0031] A pair of third ports P3 are provided on a second surface 214 of the port connection portion 212, which is perpendicular to the first surface 213 on which the second ports P2 are provided. A first port P1 is provided next to the third port P3, and connects to a first supply passage 23 to which compressed air is supplied from the air tank 12.

[0032] An exhaust section 58 housing a silencer (muffling device) is provided on the underside of the body 211. A protrusion 215 protruding from the rear side is also provided on the body 211. A connection section (not shown) is also provided on the underside of the case 210 for connecting the control device housed in the case 210 to an external power source or an electrical system cable for an in-vehicle network.

[0033] As described above, the pressure control module 20 is a unit in which a control device that controls the pneumatic circuit and a flow path are integrated. When the pressure control module 20 is attached to the vehicle 10, the protrusion 215 is fixed to a predetermined position on the vehicle body. The first port P1 is connected to a pipe that connects to the air tank 12, the second port P2 is connected to a pipe that connects to the brake valve 13, and the third port P3 is connected to the relay valve 15. The cable of the electrical system is connected to the connection part. In other words, the pressure control module 20 is the only main component that is retrofitted to the pneumatic brake system 11 to respond to abnormalities.

[0034] With reference to FIG. 3, the pneumatic circuit of the pressure control module 20 will now be described in detail. The pressure control module 20 includes a pneumatic circuit 22 and a sub-ECU (Electronic Control Unit) 32. The pressure control module 20, together with a main ECU 31, constitutes an abnormality response system 50. The main ECU 31 may be provided outside the case 210 or may be housed within the case 210.

[0035] The main ECU 31 and the sub-ECU 32 each include a calculation unit, a communication interface unit, a volatile storage unit, and a non-volatile storage unit. The calculation unit is a computer processor, and controls the pneumatic brake system 11 according to a control program stored in the non-volatile storage unit (storage medium). The calculation unit may realize at least a part of the processing it executes by a circuit such as an ASIC. The control program may be executed by one computer processor or may be executed by multiple computer processors. The main ECU 31 and the sub-ECU 32 are connected to an in-vehicle network such as a CAN (Controller Area Network) 33, and transmit and receive various information to and from each other. The control program includes an air pressure control program. The main ECU 31 performs control based on an air pressure control method. The air pressure control program may be stored in a non-transitory computer-readable medium.

[0036] The main ECU 31 inputs the ON signals output from the driver's seat operation switch 51 and the release switch 52 when they are turned on. The driver's seat operation switch 51 and the release switch 52 are switches intended to be operated by the driver and are provided near the driver's seat. When the driver's seat operation switch 51 is turned on, the emergency response system 50 is activated. The release switch 52 is a switch for stopping the operation of the emergency response system 50 when it is erroneously activated, for example. The ON signal output when the driver's seat operation switch 51 is turned on corresponds to a signal for emergency stopping the vehicle.

[0037] Furthermore, the main ECU 31 inputs an ON signal output from the passenger seat operation switch 53 when the switch is turned ON. The passenger seat operation switch 53 is a switch that is intended to be operated by a passenger other than the driver. The passenger seat operation switch 53 is provided in a position other than the driver's seat and can be operated by a passenger other than the driver. The ON signal output when the passenger seat operation switch 53 is turned ON corresponds to a signal for making an emergency stop of the vehicle.

[0038] The main ECU 31 acquires acceleration information from the acceleration sensor 54 via the CAN 33. The main ECU 31 acquires vehicle speed information directly from the vehicle speed sensor 55. When the abnormality response system 50 starts to operate, the main ECU 31 calculates a target air pressure for the pneumatic brake system 11 so that the deceleration obtained from the vehicle speed approaches the target deceleration, which is a target value, and instructs the sub-ECU 32 of the calculated target air pressure. This target deceleration can be changed by updating data stored in a storage unit such as the main ECU 31. For example, when the vehicle 10 is a passenger bus, it is assumed that there are passengers standing inside the vehicle, so the absolute value of the target deceleration is made small. Also, when the vehicle 10 is an express bus in which all passengers are seated, the absolute value of the target deceleration may be made large compared to that of a passenger bus. Also, the target deceleration can be changed according to the weight and length of the vehicle 10.

[0039] Furthermore, when the emergency response system 50 is activated, the main ECU 31 outputs an instruction signal to the in-vehicle device 56 and the exterior device 57. The in-vehicle device 56 is, for example, an accelerator interlock mechanism that disables the operation of the accelerator pedal. When the emergency response system 50 is activated, the main ECU 31 activates the accelerator interlock mechanism. In addition, the in-vehicle device 56 may be an alarm buzzer provided in the vehicle cabin, an alarm lamp provided in the vehicle cabin, or the like. For example, when the emergency response system 50 is activated, the main ECU 31 causes the alarm buzzer to output a sound and the alarm lamp to light or flash. The exterior device 57 is, for example, an air horn device 14B (see FIG. 1), a hazard lamp, a brake lamp, or the like. For example, when the emergency response system 50 is activated, the main ECU 31 drives the protection valve 14A etc., supplies air to the air horn device 14B to generate a warning sound, and turns on or flashes the hazard lights and brake lights.

[0040] The sub-ECU 32 is housed in a case 210 of the pressure control module 20, and controls various valves of the pressure control module 20. The pressure control module 20 has a first supply passage 23 connected to the air tank 12. The first supply passage 23 is connected to a front air supply passage 37 connected via a relay valve 15 to the brake chamber 17 provided on the front wheel, and a rear air supply passage 38 connected to the brake chamber 17 provided on the rear wheel. The front air supply passage 37 and the rear air supply passage 38 are each connected to a pair of third ports P3.

[0041] A relay valve 25 is connected to the first supply passage 23. The relay valve 25 has an exhaust port 25A. The exhaust port 25A is connected to an exhaust section 58 having a silencer. The relay valve 25 also has a pilot port 25B. The pilot port 25B is connected to a branch passage 26 branching off from the first supply passage 23. When the air pressure applied to the pilot port 25B from the branch passage 26 is a predetermined pressure such as atmospheric pressure, the first supply passage 23 is blocked and in an exhaust state due to the biasing force of a biasing spring or the like. When the relay valve 25 is in an exhaust state, the flow of air from the air tank 12 to the front air supply passage 37 and the rear air supply passage 38 is blocked. When the relay valve 25 is in an exhaust state, the downstream side of the relay valve 25 in the first supply passage 23 is communicated with the exhaust section 58, and the compressed air in the downstream side of the relay valve 25 in the first supply passage 23 is discharged to a predetermined pressure such as atmospheric pressure.

[0042] On the other hand, when the air pressure applied to the pilot port 25B from the branch passage 26 reaches a driving pressure higher than a predetermined pressure such as atmospheric pressure, the relay valve 25 enters a supply state in which the first supply passage 23 is connected against the biasing force of a biasing spring or the like. When the relay valve 25 enters the supply state, air is supplied from the air tank 12 to the front air supply passage 37 and the rear air supply passage 38. When the relay valve 25 enters the supply state, the first supply passage 23 is connected to the front air supply passage 37 and the rear air supply passage 38. When the pressure on the outlet side (secondary side) becomes excessively high, the relay valve 25 closes the connected state of the first supply passage 23 and enters an exhaust state.

[0043] One end of the branch passage 26 is connected to the first supply passage 23, and the other end is connected to the discharge portion 58. An intake valve 27 and an exhaust valve 28 are provided in the middle of the branch passage 26. The intake valve 27 and the exhaust valve 28 are solenoid valves and are driven by the sub-ECU 32. The intake valve 27 is provided upstream (closer to the air tank 12) of the exhaust valve 28 in the branch passage 26. The operation of the intake valve 27 is switched by turning on and off (driving / non-driving) the power from the sub-ECU 32 via a wiring 27A. The intake valve 27 is in a closed position that closes the branch passage 26 when the power is turned off and in a non-driving state. The intake valve 27 is in an open position that opens the branch passage 26 when the power is turned on and in a driving state.

[0044] The exhaust valve 28 is an electromagnetic valve whose operation is switched by turning on and off (driven / non-driven) power from the sub-ECU 32 via a wiring 28A. When the exhaust valve 28 is in a non-driven state with the power turned off, it is in an open position that communicates with the branch passage 26. When the exhaust valve 28 is in a driven state with the power turned on, it is in a closed position that closes the branch passage 26. In other words, when the intake valve 27 is in a non-driven state and in a closed position, the exhaust valve 28 opens the downstream side of the intake valve 27 and the signal supply passage 29 to the atmosphere. When the exhaust valve 28 is in a driven state, it sets the upstream side of the intake valve 27 in the branch passage 26 and the upstream side of the relay valve 25 in the first supply passage 23 to atmospheric pressure.

[0045] A signal supply path 29 that supplies an air pressure signal to the relay valve 25 and a first pressure sensor 35 are connected to the branch path 26 midway between the intake valve 27 and the exhaust valve 28. The first pressure sensor 35 detects the pressure in the branch path 26 between the intake valve 27 and the exhaust valve 28 and outputs the detected pressure to the sub-ECU 32.

[0046] The first supply passage 23 is connected to a third supply passage 30. The third supply passage 30 is connected to a pair of double check valves 36. One double check valve 36A is connected to the third supply passage 30, the front signal supply passage 24A connected to the front pressure chamber 13A of the brake valve 13, and a front air supply passage 37 for generating a braking force on the front wheels. This double check valve 36A allows the supply of compressed air from the third supply passage 30 or the front signal supply passage 24A, whichever has a higher pressure, and blocks the supply of compressed air from the lower pressure one. A second pressure sensor 39 is connected to the front air supply passage 37. The second pressure sensor 39 outputs the detected pressure to the sub-ECU 32. The pressure detected by the second pressure sensor 39 is the "supply pressure" supplied to the brake chamber 17.

[0047] The other double check valve 36B is connected to the third supply passage 30, the rear signal supply passage 24B which is connected to the rear pressure chamber 13B of the brake valve 13, and the rear air supply passage 38 which applies braking force to the rear wheels. This double check valve 36B allows the supply of compressed air from either the third supply passage 30 or the rear signal supply passage 24B, whichever has a higher pressure, and blocks the supply of compressed air from the one with a lower pressure. The front signal supply passage 24A and the rear signal supply passage 24B are each connected to a pair of second ports P2.

[0048] Next, the operation of the pressure control module 20 will be described with reference to Figures 4 and 5. Figure 4 shows the air pressure circuit 22 when the driver's seat operation switch 51 and the passenger seat operation switch 53 are not turned on.

[0049] As shown in FIG. 4, when the driver's seat operation switch 51 and the passenger seat operation switch 53 are not turned on, the sub-ECU 32 deactivates the intake valve 27 and the exhaust valve 28. In this case, the intake valve 27 is in the closed position, and the exhaust valve 28 is in the open position. As a result, the branch passage 26 downstream of the intake valve 27 is at a predetermined pressure such as atmospheric pressure because the exhaust valve 28 is in the open position. Therefore, the air pressure applied to the pilot port 25B is also at a predetermined pressure, and the relay valve 25 is in the exhaust state. When the relay valve 25 is in the exhaust state, the compressed air downstream of the relay valve 25 in the third supply passage 30 and the first supply passage 23 is discharged from the discharge portion 58, and the third supply passage 30 is at a predetermined pressure. Furthermore, when the brake pedal 13C is depressed, an air pressure signal is supplied to the front signal supply passage 24A and the rear signal supply passage 24B. As a result, the pressure in the front signal supply path 24A and the rear signal supply path 24B becomes higher than that in the third supply path 30, so that the double check valves 36A and 36B block the flow of air from the third supply path 30 to the front air supply path 37 and the rear air supply path 38, respectively. Then, air pressure signals are supplied from the front signal supply path 24A and the rear signal supply path 24B to the front air supply path 37 and the rear air supply path 38. As a result, a large amount of compressed air is supplied from the air tank 12 to the relay valve 15 by supplying the air pressure signal to the relay valve 15. When the relay valve 15 supplies compressed air to the brake chamber 17, a braking force is applied to the wheels. The air pressure circuit including the front signal supply path 24A and the rear signal supply path 24B corresponds to a brake control circuit.

[0050] FIG. 5 shows the air pressure circuit 22 when at least one of the driver's seat operation switch 51 and the passenger's seat operation switch 53 is turned on. When at least one of the driver's seat operation switch 51 and the passenger's seat operation switch 53 is turned on, the sub-ECU 32 receives a pressure command transmitted from the main ECU 31. The sub-ECU 32 drives the intake valve 27 and the exhaust valve 28 based on the pressure command. As a result, the intake valve 27 is in an open position, and the exhaust valve 28 is in a closed position. The compressed air in the air tank 12 is supplied to the branch path 26 between the intake valve 27 and the exhaust valve 28 via the first supply path 23. When the pressure in the branch path 26 between the intake valve 27 and the exhaust valve 28 reaches the drive pressure, this pressure is applied to the relay valve 25 via the pilot port 25B, and the relay valve 25 is in a supply state. As a result, compressed air is supplied to the third supply path 30 via the first supply path 23 and the relay valve 25.

[0051] When compressed air is supplied to the third supply path 30, the pressure in the third supply path 30 becomes higher than the front signal supply path 24A and the rear signal supply path 24B. Therefore, the double check valve 36 allows air to flow from the third supply path 30 to the front air supply path 37 and the rear air supply path 38, and blocks air from the front signal supply path 24A and the rear signal supply path 24B to the front air supply path 37 and the rear air supply path 38. Note that the air pressure circuit including the third supply path 30 and the flow paths (the first supply path 23, the branch path 26, etc.) that connect the intake valve 27, the exhaust valve 28, and the relay valve 25 corresponds to an abnormality brake control circuit.

[0052] In this way, by providing the pressure control module 20 between the brake valve 13 and the relay valve 15, when the driver's seat operation switch 51 and the passenger seat operation switch 53 are turned on, the air pressure drive command system switches from the system via the brake valve 13 to a system in which air is directly supplied from the air tank 12. Therefore, even if an air pressure signal is not input from the brake valve 13, the brake chamber 17 can be operated to generate braking force.

[0053] The sub-ECU 32 also acquires the detected pressure from the first pressure sensor 35 and the second pressure sensor 39 at a predetermined timing. For example, when the relay valve 25 is to be maintained in a supply state, the sub-ECU 32 drives or deactivates the intake valve 27 and the exhaust valve 28 so that the pressure detected by the first pressure sensor 35 falls within a predetermined range. When the main ECU 31 transmits a pressure command to the sub-ECU 32 to increase the pressure stepwise in order to stop the vehicle 10 gently, the sub-ECU 32 determines whether the pressure detected by the second pressure sensor 39 has reached a first pressure threshold value. When the sub-ECU 32 determines that the detected pressure has not reached the first pressure threshold value, the sub-ECU 32 drives the intake valve 27 and the exhaust valve 28 to maintain the relay valve 25 in a supply state. On the other hand, when the pressure detected by the second pressure sensor 39 reaches the first pressure threshold, the sub-ECU 32 deactivates the intake valve 27 and the exhaust valve 28 and sets the relay valve 25 to the exhaust state. Then, the sub-ECU 32 waits for the next pressure command from the main ECU 31. The air pressure in the signal supply path 29 is controlled by the intake valve 27 and the exhaust valve 28, and the desired air pressure is supplied to the third supply path 30 by driving the relay valve 25.

[0054] Next, the procedure of the process performed by the main ECU 31 in response to an abnormality will be described with reference to Fig. 6 to Fig. 8. The process shown in Fig. 6 is a process for controlling the air system, and is started when the driver's seat operation switch 51 or the passenger seat operation switch 53 is operated and the main ECU 31 inputs an operation signal transmitted from the switch. It is also assumed that the main ECU 31 acquires vehicle information from the acceleration sensor 54 and the vehicle speed sensor 55 at a predetermined timing. In Fig. 7, the vehicle speed V is indicated by a solid line, the pressure Pa of the air supplied to the brake chamber 17 is indicated by a thick line, and the deceleration a is indicated by a dashed line.

[0055] 6 and 7, when an operation signal is input at time t1, the main ECU 31 judges whether the passenger seat operation switch 53 has been operated (step S1). That is, the main ECU 31 judges whether the input operation signal is a signal from the driver's seat operation switch 51 or a signal from the passenger seat operation switch 53. Then, when the main ECU 31 judges that the driver's seat operation switch 51 has been operated (step S1: NO), the process proceeds to step S4. Here, the phase up to time t1 when the passenger seat operation switch 53 is operated is defined as the "system standby section S0."

[0056] On the other hand, when the main ECU 31 determines that the passenger seat operation switch 53 has been operated (step S1: YES), it instructs the sub-ECU 32 of the gentle braking pressure Pa1 required for gentle braking (step S2). Gentle braking is braking in which the absolute value of the deceleration is relatively small, or braking for which the brakes are applied for a short period of time, and enables a return to normal driving when the release switch 52 is operated immediately afterwards. Then, the gentle braking pressure is transmitted to the sub-ECU 32. The sub-ECU 32 drives the intake valve 27 and the exhaust valve 28 based on the pressure instruction to supply pressure to the brake chamber 17 (see FIG. 5).

[0057] The main ECU 31 judges whether the gentle braking time T1 has elapsed (step S3). That is, the main ECU 31 judges whether the gentle braking time T1 has elapsed based on the elapsed time from the time when the pressure instruction is transmitted to the sub ECU 32, the time when the vehicle 10 starts deceleration, or the time when a predetermined response signal is received from the sub ECU 32. This gentle braking time T1 is the time required for the driver to operate the release switch 52 when the passenger seat operation switch 53 is erroneously operated even though the driver is in a normal state. Then, when the main ECU 31 judges that the gentle braking time T1 has not elapsed (step S3: NO), it continues gentle braking while instructing the sub ECU 32 to apply the gentle braking pressure Pa1 (step S2). Here, the phase from time t1 to time t2 when the gentle braking time T1 has elapsed is defined as the "attention calling braking section Ph1".

[0058] On the other hand, when the main ECU 31 determines that the gentle braking time has elapsed (step S3: YES), it instructs the sub-ECU 32 to perform main braking. Main braking is intended to decelerate the vehicle 10 at a deceleration whose absolute value is greater than that of gentle braking, and finally stop the vehicle. The main ECU 31 acquires a target deceleration for main braking stored in its own memory, and calculates the predetermined increase pressure ΔPa2 and the predetermined decrease pressure ΔPa4 by comparing the target deceleration with the deceleration obtained from the acquired vehicle speed. Then, it transmits the calculated air pressure to the sub-ECU 32. The sub-ECU 32 drives the intake valve 27 and the exhaust valve 28 based on the pressure instruction (see FIG. 5). Note that the following step S4 and subsequent steps correspond to a "deceleration step" in which air is supplied to the brake chamber 17 to decelerate the vehicle.

[0059] The main ECU 31 increases the supply pressure by increasing the predetermined increased pressure ΔPa2 every predetermined time ΔT2 (step S4). That is, the main ECU 31 determines the supply pressure every predetermined time ΔT2. The main ECU 31 transmits the determined air pressure to the sub-ECU 32. The sub-ECU 32 drives the intake valve 27 and the exhaust valve 28 based on the pressure command transmitted from the main ECU 31 to supply air to the brake chamber 17 to the determined target pressure.

[0060] Next, the main ECU 31 judges whether the supply pressure is equal to or greater than the upper limit pressure Pa3 (step S5). That is, since the supply pressure increases as the predetermined increased pressure ΔPa2 is increased, the main ECU 31 judges whether the increased supply pressure is equal to or greater than the upper limit pressure Pa3. Then, when the main ECU 31 judges that the supply pressure is less than the upper limit pressure Pa3 (step S5: NO), the process proceeds to step S4, and the supply pressure is increased by the predetermined increased pressure ΔPa2 every predetermined time ΔT2. Here, the phase from time t2 to time t3 at which the pressure becomes equal to or greater than the upper limit pressure Pa3 is defined as the "braking force generation section Ph2". In addition, in Non-Patent Document 1, an upper limit of the deceleration rate in an emergency stop is set, and when the deceleration rate is greater than the upper limit deceleration rate (for example, 2.45 m / ss), it is necessary to interrupt deceleration or exhaust air so that the supply pressure becomes less than the upper limit pressure Pa3.

[0061] On the other hand, when the main ECU 31 determines that the supply pressure is equal to or higher than the upper limit pressure Pa3 (step S5: YES), it keeps the supply pressure constant at the upper limit pressure Pa3 (step S6). That is, by keeping the supply pressure constant at the upper limit pressure Pa3, the main ECU 31 keeps the braking force of the brake chamber 17 constant, thereby making it possible to suppress abrupt changes in speed. The main ECU 31 transmits the determined air pressure to the sub-ECU 32. The sub-ECU 32 drives the intake valve 27 and the exhaust valve 28 based on the pressure command transmitted from the main ECU 31, and supplies air to the brake chamber 17 so as to reach the determined target pressure.

[0062] Next, the main ECU 31 judges whether the vehicle speed is equal to or lower than a predetermined speed Vth (step S7). That is, the main ECU 31 judges whether the vehicle speed is reduced by the braking of the brake chamber 17 and is equal to or lower than the predetermined speed Vth. The predetermined speed Vth is a speed at which the vehicle can be easily stopped in a short time, for example, a low speed such as 10 to 20 km per hour, a speed immediately before stopping, or a lower limit value measurable by the vehicle speed sensor 55. Then, when the main ECU 31 judges that the vehicle speed is higher than the predetermined speed Vth (step S7: NO), it repeats the judgment while instructing the sub ECU 32 to the upper limit pressure Pa3 until the vehicle speed becomes equal to or lower than the predetermined speed Vth (step S7). Here, the phase from time t3 to time t4 at which the vehicle speed becomes equal to or lower than the predetermined speed Vth is set as a "constant deceleration braking section Ph3".

[0063] On the other hand, when the main ECU 31 determines that the vehicle speed is equal to or lower than the predetermined speed Vth (step S7: YES), it reduces the air pressure supplied by the reduced predetermined pressure ΔPa4 every predetermined time ΔT4 (step S8). That is, the main ECU 31 determines the supply pressure every predetermined time ΔT4. The main ECU 31 transmits the determined air pressure to the sub ECU 32. The sub ECU 32 drives the intake valve 27 and the exhaust valve 28 based on the pressure command transmitted from the main ECU 31 to supply air to the brake chamber 17 so as to reach the determined target pressure. Note that step S8 corresponds to an "air pressure reducing step" for reducing the air pressure supplied to the brake chamber 17 when the decelerating vehicle becomes equal to or lower than the predetermined speed Vth.

[0064] Next, the main ECU 31 judges whether the supply pressure is equal to or less than the lower limit pressure Pa4 (step S9). That is, since the supply pressure is reduced by reducing the predetermined reduced pressure ΔPa4, the main ECU 31 judges whether the reduced supply pressure is equal to or less than the lower limit pressure Pa4. Then, when the main ECU 31 judges that the supply pressure is greater than the lower limit pressure Pa4 (step S9: NO), the main ECU 31 proceeds to step S8, and reduces the predetermined reduced pressure ΔPa4 every predetermined time ΔT4 and supplies the pressure.

[0065] On the other hand, when the main ECU 31 determines that the supply pressure is equal to or lower than the lower limit pressure Pa4 (step S9: YES), the main ECU 31 keeps the supply pressure constant at the lower limit pressure Pa4 (step S10). That is, by keeping the supply pressure constant at the lower limit pressure Pa4, the main ECU 31 can keep the braking force of the brake chamber 17 constant and suppress abrupt changes in speed. The main ECU 31 transmits the determined air pressure to the sub ECU 32. The sub ECU 32 drives the intake valve 27 and the exhaust valve 28 based on the pressure command transmitted from the main ECU 31 to supply air to the brake chamber 17 so as to reach the determined target pressure.

[0066] Next, the main ECU 31 judges whether or not the stop determination time T4 has elapsed since the pressure reached the lower limit pressure Pa4 (step S11). That is, the main ECU 31 judges whether or not the stop determination time T4, which is the time required for the vehicle to stop, has elapsed. If the main ECU 31 judges that the stop determination time T4 has not elapsed (step S11: NO), the main ECU 31 repeats the judgment until the stop determination time T4 has elapsed while instructing the sub ECU 32 to the lower limit pressure Pa4 (step S11). Note that the stop determination time T4 corresponds to a predetermined time. Here, the phase from time t4 to time t5, when the stop determination time T4 has elapsed since the pressure reached the lower limit pressure Pa4, is defined as a "braking force reduction section Ph4". Also, the phase after time t5 is defined as a "vehicle stop braking section Ph5".

[0067] On the other hand, when the main ECU 31 determines that the stop determination time T4 has elapsed (step S11: YES), it keeps the supply pressure constant at the stop pressure Pa5 (step S12). That is, the main ECU 31 increases the supply pressure from the lower limit pressure Pa4 to the stop pressure Pa5 and continues to supply the stop pressure Pa5 until the end. The main ECU 31 transmits the determined air pressure to the sub ECU 32. The sub ECU 32 drives the intake valve 27 and the exhaust valve 28 based on the pressure command transmitted from the main ECU 31 to supply air to the brake chamber 17 to the determined target pressure. The stop pressure Pa5 corresponds to a predetermined value.

[0068] Next, the main ECU 31 judges whether the abnormality response has been completed (step S13). The abnormality response may be determined to have been completed when the vehicle 10 stops and the parking brake is activated, or when the ignition switch is turned off, or at other times. If the main ECU 31 judges that the abnormality response has not been completed (step S13: NO), the main ECU 31 continues to instruct the sub-ECU 32 to supply the stop pressure Pa5 (step S4). On the other hand, if the main ECU 31 judges that the abnormality response has been completed (step S13: YES), the main ECU 31 ends the abnormality response process.

[0069] In addition to responding to an abnormality in the air system, the main ECU 31 also activates the in-vehicle device 56 and the exterior device 57 at a predetermined timing, such as the timing to start executing the main braking. This notifies the occupants of the vehicle 10 that an abnormality has occurred, and also alerts other vehicles traveling around the vehicle 10.

[0070] Next, the procedure of the release process when the release switch 52 is operated will be described with reference to Fig. 8. The process shown in Fig. 8 is started when the driver's seat operation switch 51 or the passenger's seat operation switch 53 is operated and the main ECU 31 inputs the operation signal.

[0071] 8, the main ECU 31 determines whether the release switch 52 has been operated (step S20). That is, the main ECU 31 determines whether an operation signal has been input from the release switch 52. Then, when the main ECU 31 determines that the release switch 52 has been operated (step S20: YES), it transmits a braking release instruction to the sub ECU 32 (step S21). The sub ECU 32 that has received the release instruction deactivates the intake valve 27 and the exhaust valve 28, and cuts off the supply of air from the air tank 12 to the brake chamber 17.

[0072] On the other hand, when the main ECU 31 determines that the release switch 52 has not been operated (step S20: NO), it determines whether or not the abnormality response has been completed (step S22). Then, when the main ECU 31 determines that the abnormality response has not been completed (step S22: NO), it proceeds to step S20. On the other hand, when the main ECU 31 determines that the abnormality response has been completed (step S22: YES), it ends the release process.

[0073] Next, the effects of this embodiment will be described. (1) By reducing the air pressure supplied to the brake chamber 17 when the vehicle speed drops below a predetermined speed Vth during deceleration, the braking force is weakened, and the change in acceleration (jerk) at the moment the vehicle comes to a complete stop can be reduced. This makes it possible to suppress the load on the occupants when the vehicle makes an emergency stop.

[0074] (2) Since the vehicle comes to a stop a predetermined time after the air pressure falls below the lower limit pressure Pa4, the braking force of the brake chamber 17 can be increased by increasing the air pressure supplied to the brake chamber 17 to above the stopping pressure Pa5, thereby preventing the vehicle from moving from a stopped state.

[0075] (3) When the vehicle decelerates to a certain extent during deceleration, the air pressure supplied to the brake chamber 17 can be kept constant at the upper limit pressure Pa3, thereby making it possible to keep the braking force of the brake chamber 17 constant and suppressing sudden changes in the vehicle speed V.

[0076] (4) Since the air pressure supplied to the brake chamber 17 is determined every predetermined time ΔT2 and every predetermined time ΔT4, the amount of calculation can be reduced compared to determining the air pressure supplied to the brake chamber 17 at any time.

[0077] (5) Normally, when the driver operates the brakes, the brake valve supplies air to the brake chamber 17. However, in the event of an abnormality in the driver's condition, the control unit can control the air pressure circuit to supply air to the brake chamber 17 instead of the brake valve, thereby making it possible to bring the vehicle to an emergency stop.

[0078] (6) Since sudden braking immediately after the passenger switch is operated may startle the passenger, the brake chamber 17 is first made to perform gentle braking to alert the passenger. (7) The first communication state, in which the brake valve and the brake chamber 17 are connected and air is supplied from the second port to the third port, is switched to a second communication state, in which the air tank and the brake chamber 17 are connected and air is supplied from the first port to the third port. Therefore, air can be automatically supplied from the air tank to the brake chamber 17 to generate braking force.

[0079] (Other embodiments) The above embodiment can be modified as follows: The above embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0080] In the above embodiment, the predetermined time ΔT2 and the predetermined time ΔT4 may be the same or different. In the above embodiment, the main ECU 31 determines the pressure to be supplied to the brake chamber 17 at every predetermined time ΔT2 and every predetermined time ΔT4. However, as shown in Fig. 9, the main ECU 31 may perform calculations at any time to determine the pressure to be supplied to the brake chamber 17. In this way, the pressure to be supplied to the brake chamber 17 can be accurately determined according to the vehicle speed to perform braking.

[0081] In the above embodiment, it is determined whether the stop determination time T4 has elapsed since the lower limit pressure Pa4 was reached. However, it may be determined whether the stop determination time has elapsed since the predetermined speed Vth was reached. With this configuration, the vehicle is stopped after the stop determination time T4 has elapsed since the speed became equal to or lower than the predetermined speed Vth, so that the braking force of the brake chamber 17 is increased by increasing the air pressure supplied to the brake chamber 17 to the stop pressure Pa5 or higher, and it is possible to prevent the vehicle from moving from the stopped state.

[0082] In the above embodiment, the stopping pressure is constant at Pa5 after the stop determination time T4 has elapsed, but the parking brake or the electric parking brake may be applied to maintain the vehicle in a stopped state.

[0083] In the above embodiment, when the passenger seat operation switch 53 is operated, the gentle braking pressure Pa1 is supplied to the brake chamber 17 for the gentle braking time T1. However, the gentle braking time T1 may be used as a warning time, and pressure may not be supplied to the brake chamber 17.

[0084] In the above embodiment, the air pressure control device and the air pressure circuit are applied to the vehicle 10 with a full air brake. However, the air pressure control device and the air pressure circuit can be applied to vehicles having other types of brake systems. As shown in FIG. 10, the pressure control module 20 can be applied to the vehicle 10 having an air-over-hydraulic type brake mechanism. In this brake mechanism, the pressure control module 20 is connected to brake boosters 100-102 via an ABS control valve 16. The brake boosters 100-102 are boosters for the front wheels, the rear left wheel, and the rear right wheel, and generate braking force on the wheels by increasing the hydraulic pressure of the hydraulic circuit using air pressure. Also, as shown in FIG. 11, the pressure control module 20 may be applied to a brake mechanism including a brake booster 103 for the front wheels, a brake booster 104 for the rear wheels, and an ABS control valve 105 provided in the hydraulic circuit. Alternatively, the air pressure control device and the air pressure circuit can be applied to brake mechanisms other than those shown in FIG. 10 and FIG. 11.

[0085] In the above embodiment, the body 211 is made of metal, but instead, it may be made of resin. For example, the body 211 is formed by casting, but instead of or in addition to this, the body 211 may be formed by combining parts formed by pressing or cutting.

[0086] In the above embodiment, the air tank 12 is divided into three tanks, but it may be one tank, or two or four or more tanks. The connection relationship between the air tank 12 and the pneumatic device may be changed as appropriate. For example, the first port P1 of the pressure control module 20 may be connected to a tank other than the third tank 12C.

[0087] In the above embodiment, the main ECU 31 may receive an ON signal or the like from the driver's seat operation switch 51, the release switch 52, and the passenger seat operation switch 53 via an in-vehicle network such as the CAN 33. The in-vehicle network may be a network other than the CAN 33, such as FlexRay (registered trademark), Ethernet (registered trademark), or the like.

[0088] In the above embodiment, the main ECU 31 obtains the acceleration information from the acceleration sensor 54. However, instead of this, the main ECU 31 may obtain the acceleration information from the vehicle speed sensor 55. Note that acceleration is also included in the "vehicle speed" in the claims.

[0089] In the above embodiment, the abnormality response system 50 includes the main ECU 31 and the sub-ECU 32. Instead of or in addition to this, the main ECU 31 and the sub-ECU 32 may be configured as one ECU or other control circuit having the functions of the first control unit and the functions of the second control unit. Alternatively, these functions may be distributed among three or more ECUs or other control circuits.

[0090] In the above embodiment, the emergency response system 50 may include a main switch (not shown) that can turn on / off the function of the system. By performing a predetermined operation on the main switch or controlling the main switch with a predetermined control device, for example, the operations of the driver's seat operation switch 51, the release switch 52, and the passenger seat operation switch 53 can be disabled.

[0091] In the above embodiment, the pneumatic circuit 22 drives the pneumatically driven relay valve 25 by the intake valve 27 and the exhaust valve 28. Alternatively, a solenoid valve may be provided in the first supply path 23, and the first supply path 23 may be opened and closed by this solenoid valve.

[0092] In the above embodiment, the relay valve 25 may be omitted and the signal supply path 29 may be directly connected to the third supply path. Even with this configuration, the air pressure in the signal supply path 29 can be controlled by the intake valve 27 and the exhaust valve 28 to supply a desired air pressure to the third supply path 30.

[0093] In the above embodiment, the pneumatic circuit 22 includes the double check valve 36 that switches the air supply direction depending on the air pressure. Instead of the double check valve 36, a solenoid valve that is driven and deactivated by the sub-ECU 32 may be provided. When the driver's seat operation switch 51 or the passenger's seat operation switch 53 is turned on, the sub-ECU 32 drives (or deactivates) the solenoid valve to switch the air supply direction.

[0094] In the above embodiment, the first pressure sensor 35 may be omitted. In this case, the sub-ECU 32 performs control using the pressure detected by the second pressure sensor 39 instead of the pressure detected by the first pressure sensor 35.

[0095] In the above embodiment, the abnormality response is performed by turning on the driver's seat operation switch 51 and the passenger seat operation switch 53. Instead of or in addition to this, a live body detection device that detects the driver's fatigue state or health state may be used. The live body detection device detects the driver's driving state using one or more parameters such as the position and posture of the driver's face and head, eyelids, eye gaze, pulse rate, heart rate, body temperature, etc. In this aspect, the live body detection device transmits an abnormality signal when it detects an abnormality in the driver. Alternatively, an ECU mounted on the vehicle may transmit an abnormality signal when it detects an abnormality in driving by comparing the vehicle state, such as the vehicle speed and the presence or absence of operation of the accelerator pedal or brake pedal, with road information.

[0096] In the above embodiment, the pneumatic pressure control device is described as being retrofitted to a vehicle in use in which the brake command system is a pneumatic circuit, but it may be retrofitted to a vehicle equipped with an EBS. Also, the pneumatic pressure control device may be installed in a new vehicle.

[0097] In the above embodiment, the air pressure control device has been described as being mounted on a vehicle such as a bus. The vehicle may be a truck, construction machinery, etc., in addition to a bus. In addition, the air pressure control device may be mounted on other vehicles such as passenger cars and railroad cars.

[0098] · Similar problems exist even in new cars or used cars in which the brake mechanism is controlled by a hydraulic circuit, since driver abnormalities can occur. For this reason, the pressure control module 20 of the above embodiment may be applied to a vehicle in which the command system to the brake mechanism is hydraulic. In a hydraulic circuit, the pressure control module 20 operates in the same manner as in the above embodiment. In this aspect, the brake mechanism to be controlled may be a mechanism other than the brake chamber. Note that the hydraulic circuit and the pneumatic circuit are examples of circuits driven by fluid pressure.

[0099] The present invention can be applied not only to pneumatic brakes but also to hydraulic brakes. According to one aspect of the hydraulic brake, there is provided a hydraulic control device comprising a hydraulic circuit configured to supply oil to a brake mechanism that applies a braking force to a wheel, and a control unit configured to control the hydraulic pressure supplied from the hydraulic circuit to the brake mechanism, the control unit configured to supply oil to the brake mechanism to decelerate the vehicle based on a signal for bringing the vehicle to an emergency stop, and to reduce the hydraulic pressure supplied to the brake mechanism when the vehicle speed drops below a predetermined speed.

[0100] According to the above configuration, when the vehicle decelerates and reaches a predetermined speed or less, the hydraulic pressure supplied to the brake mechanism is reduced to weaken the braking force, thereby reducing the change in acceleration (jerk) at the moment the vehicle comes to a complete stop, thereby reducing the load on the occupants when the vehicle makes an emergency stop.

[0101] In the above hydraulic control device, the control unit may be configured to increase the hydraulic pressure after the pressure reduction to a predetermined value or more after a predetermined time has elapsed since the vehicle becomes equal to or less than the predetermined speed.

[0102] According to the above configuration, the vehicle is stopped a predetermined time after the vehicle speed drops below a predetermined speed, so by increasing the hydraulic pressure supplied to the brake mechanism to a predetermined value or above, the braking force of the brake mechanism is increased, and the vehicle can be prevented from moving from a stopped state.

[0103] In the above hydraulic control device, the control unit may be configured to increase the hydraulic pressure supplied to the brake mechanism to above a predetermined value after a predetermined time has elapsed since the hydraulic pressure became equal to or lower than a lower limit pressure due to the reduction in pressure.

[0104] According to the above configuration, the vehicle is stopped a predetermined time after the pressure falls below the lower limit pressure, so by increasing the hydraulic pressure supplied to the brake mechanism to a predetermined value or above, the braking force of the brake mechanism is increased, and the vehicle can be prevented from moving from a stopped state.

[0105] With regard to the above hydraulic control device, the control unit may be configured to keep the hydraulic pressure supplied to the brake mechanism constant at the upper limit pressure when the hydraulic pressure supplied to the brake mechanism becomes equal to or greater than an upper limit pressure during deceleration of the vehicle.

[0106] According to the above configuration, the hydraulic pressure supplied to the brake mechanism can be kept constant when the vehicle has decelerated to a certain extent during deceleration, thereby making it possible to keep the braking force of the brake mechanism constant and suppressing sudden changes in speed.

[0107] In the above hydraulic control device, the control unit may be configured to determine the hydraulic pressure to be supplied to the brake mechanism at predetermined time intervals. According to the above configuration, the hydraulic pressure to be supplied to the brake mechanism is determined at predetermined time intervals, so the amount of calculation can be reduced compared to when the hydraulic pressure to be supplied to the brake mechanism is determined at any time.

[0108] In the above hydraulic control device, the hydraulic circuit may be configured to supply oil to the brake mechanism in place of a brake valve that supplies oil to the brake mechanism when a brake operation is performed.

[0109] According to the above configuration, normally, the brake valve supplies oil to the brake mechanism when the driver operates the brakes, but in the event of an abnormality in the driver's condition, the control unit controls the hydraulic circuit instead of the brake valve to supply oil to the brake mechanism, thereby enabling an emergency stop of the vehicle.

[0110] In the above hydraulic control device, the control unit may be configured to supply hydraulic pressure for gentle braking to the brake mechanism when an abnormality signal indicating an abnormality due to the operation of a passenger switch is acquired as a signal for bringing the vehicle to an emergency stop. According to the above configuration, since the passenger would be surprised if sudden braking was performed immediately after the operation of the passenger switch, it is possible to call the passenger's attention by first causing the brake mechanism to perform gentle braking.

[0111] According to one aspect of the present hydraulic brake, a hydraulic control method for a hydraulic control device is provided. The hydraulic control device includes a hydraulic circuit configured to supply oil to a brake mechanism that applies a braking force to a wheel, and a control unit configured to control the hydraulic pressure supplied from the hydraulic circuit to the brake mechanism. The hydraulic control method includes a deceleration step of supplying oil to the brake mechanism based on a signal for emergency stopping the vehicle to decelerate the vehicle, and a hydraulic pressure reduction step of reducing the hydraulic pressure supplied to the brake mechanism when the vehicle during the deceleration reaches a predetermined speed or less.

[0112] According to the above method, the hydraulic pressure supplied to the brake mechanism is reduced when the vehicle speed drops below a predetermined speed during deceleration, thereby weakening the braking force and reducing the change in acceleration (jerk) at the moment the vehicle comes to a complete stop, thereby reducing the load on the occupants when the vehicle makes an emergency stop.

[0113] According to one aspect of the present hydraulic brake, there is provided a hydraulic control program for a hydraulic control device. The hydraulic control device includes a hydraulic circuit configured to supply oil to a brake mechanism that applies a braking force to a wheel, and a control unit configured to control the hydraulic pressure supplied from the hydraulic circuit to the brake mechanism. When the hydraulic control program runs on a computer of the hydraulic control device, it causes the hydraulic control device to execute a deceleration step of supplying oil to the brake mechanism to decelerate the vehicle based on a signal for emergency stopping the vehicle, and a hydraulic pressure reduction step of reducing the hydraulic pressure supplied to the brake mechanism when the vehicle during the deceleration reaches or falls below a predetermined speed.

[0114] According to the above program, when the vehicle decelerates and reaches a predetermined speed or less, the hydraulic pressure supplied to the brake mechanism is reduced to weaken the braking force, thereby reducing the change in acceleration (jerk) at the moment the vehicle comes to a complete stop, thereby reducing the load on the occupants when the vehicle makes an emergency stop.

[0115] According to one aspect of the present hydraulic brake, a non-transitory computer-readable medium is provided that stores a hydraulic control program, which, when executed in a computer of a hydraulic control device including a hydraulic circuit configured to supply oil to a brake mechanism that applies a braking force to a wheel and a control unit configured to control the hydraulic pressure supplied from the hydraulic circuit to the brake mechanism, causes the hydraulic control device to supply oil to the brake mechanism based on a signal for bringing the vehicle to an emergency stop, thereby decelerating the vehicle, and to reduce the hydraulic pressure supplied to the brake mechanism when the vehicle during the deceleration reaches or falls below a predetermined speed.

[0116] The present invention can also be applied to electric brakes. According to one aspect of the electric brake, there is provided an electric control device comprising an electric circuit configured to supply electric power to a brake mechanism that applies a braking force to a wheel, and a control unit configured to control the electric power supplied from the electric circuit to the brake mechanism, the control unit configured to supply electric power to the brake mechanism based on a signal for bringing the vehicle to an emergency stop to decelerate the vehicle, and to supply electric power to the brake mechanism when the vehicle speed drops below a predetermined speed to perform gradual deceleration.

[0117] According to the above configuration, when the vehicle decelerates and reaches a predetermined speed or less, the braking force is weakened by supplying power to the brake mechanism, thereby reducing the change in acceleration (jerk) at the moment the vehicle comes to a complete stop, thereby reducing the load on the occupants when the vehicle makes an emergency stop.

[0118] In the above-described electrically-driven control device, the control unit may be configured to increase the power supply after deceleration to a predetermined value or more after a predetermined time has elapsed since the vehicle speed became equal to or less than the predetermined speed.

[0119] According to the above configuration, the vehicle is stopped a predetermined time after the vehicle speed drops below a predetermined speed, so by increasing the power supplied to the brake mechanism above a predetermined value, the braking force of the brake mechanism is increased, and the vehicle can be prevented from moving from a stopped state.

[0120] In the above-mentioned electrically-driven control device, the control unit may be configured to increase the power supplied to the brake mechanism to above a predetermined value after a predetermined time has elapsed since the braking force becomes equal to or lower than a lower limit value due to the deceleration.

[0121] According to the above configuration, the vehicle is stopped a predetermined time after the lower limit value is reached, and therefore, by increasing the power supplied to the brake mechanism to above a predetermined value, the braking force of the brake mechanism is increased, thereby preventing the vehicle from moving from a stopped state.

[0122] With regard to the above-mentioned electrically-driven control device, the control unit may be configured to keep the braking force of the brake mechanism constant at the upper limit value when the braking force of the brake mechanism becomes equal to or exceeds an upper limit value during deceleration of the vehicle.

[0123] According to the above configuration, the braking force of the brake mechanism can be made constant when the vehicle has decelerated to a certain degree during deceleration, and abrupt changes in speed can be suppressed. In the above-mentioned electrically-driven control device, the control unit may be configured to determine the amount of electric power to be supplied to the brake mechanism at predetermined time intervals.

[0124] According to the above configuration, since the power to be supplied to the brake mechanism is determined at predetermined time intervals, the amount of calculation can be reduced compared to when the power to be supplied to the brake mechanism is determined at any time.

[0125] In the above electric control device, the control unit may be configured to supply power for gentle braking to the brake mechanism when it receives an abnormality signal indicating an abnormality due to the operation of the occupant switch as a signal for bringing the vehicle to an emergency stop. According to the above configuration, since the occupant would be surprised if sudden braking was performed immediately after the operation of the occupant switch, it is possible to call the occupant's attention by first causing the brake mechanism to perform gentle braking.

[0126] According to one aspect of the present electric brake, there is provided an electric control method for an electric control device. The electric control device includes an electric circuit configured to supply electric power to a brake mechanism that applies a braking force to a wheel, and a control unit configured to control the electric power supplied from the electric circuit to the brake mechanism. The electric control method includes a deceleration step of supplying electric power to the brake mechanism based on a signal for emergency stopping the vehicle to decelerate the vehicle, and a gentle braking step of controlling the electric power supplied to the brake mechanism when the vehicle speed during the deceleration drops below a predetermined speed.

[0127] According to the above method, when the vehicle decelerates and reaches a predetermined speed or less, the braking force is weakened by controlling the power supplied to the brake mechanism, thereby reducing the change in acceleration (jerk) at the moment the vehicle comes to a complete stop, thereby reducing the load on the occupants when the vehicle makes an emergency stop.

[0128] According to one aspect of the electric brake, an electric control program for an electric control device is provided. The electric control device includes an electric circuit configured to supply electric power to a brake mechanism that applies a braking force to a wheel, and a control unit configured to control the electric power supplied from the electric circuit to the brake mechanism. When the electric control program runs on a computer of the electric control device, it causes the electric control device to execute a deceleration step of supplying electric power to the brake mechanism to decelerate the vehicle based on a signal for causing the electric control device to make an emergency stop of the vehicle, and a gentle braking step of controlling the electric power supplied to the brake mechanism when the vehicle speed during the deceleration drops below a predetermined speed.

[0129] According to the program, when the vehicle decelerates and reaches a predetermined speed or below, the power supplied to the brake mechanism is reduced to weaken the braking force, thereby reducing the change in acceleration (jerk) at the moment the vehicle comes to a complete stop, thereby reducing the load on the occupants when the vehicle makes an emergency stop.

[0130] According to one aspect of the present electric brake, a non-transitory computer-readable medium storing an electric control program is provided. The electric control program, when executed in a computer of an electric control device including an electric circuit configured to supply electric power to a brake mechanism that applies a braking force to a wheel and a control unit configured to control the electric power supplied from the electric circuit to the brake mechanism, causes the electric control device to supply electric power to the brake mechanism based on a signal for bringing the vehicle to an emergency stop, thereby decelerating the vehicle, and to control the electric power supplied to the brake mechanism when the vehicle speed during the deceleration drops below a predetermined speed, thereby performing gentle braking. [Explanation of symbols]

[0131] 10...vehicle, 11...pneumatic brake system, 12...air tank, 13...brake valve, 13A...front pressure chamber, 13B...rear pressure chamber, 13C...brake pedal, 14A...protection valve, 14B...air horn device, 15...relay valve, 16...ABS control valve, 17...brake chamber, 18...air piping, 20...pressure control module, 21...case, 21A...port connection, 21D...protrusion, 22...pneumatic circuit, 23...first supply path, 24A...front signal supply path, 24B...rear signal supply path, 25...relay valve, 25A...exhaust port, 25B...pilot port, 26...branch path, 27...intake valve, 27A...wiring, 28... Exhaust valve, 28A...wiring, 29...signal supply path, 30...third supply path, 31...main ECU, 32...sub ECU, 33...CAN, 35...first pressure sensor, 36, 36A, 36B...double check valve, 37...front air supply path, 38...front air supply path, 39...second pressure sensor, 39...pressure sensor, 50...abnormality response system, 51...driver's seat operation switch, 52...release switch, 53...passenger seat operation switch, 54...acceleration sensor, 55...vehicle speed sensor, 56...interior device, 57...exterior device, 58...exhaust section, 100~104...brake booster, 105...ABS control valve, P1...first port, P2...second port, P3...third port.

Claims

1. a pneumatic circuit configured to supply air to a brake mechanism that applies a braking force to a wheel; a control unit configured to control the air pressure supplied from the air pressure circuit to the brake mechanism, The control unit is configured to supply air to the brake mechanism based on a signal for bringing the vehicle to an emergency stop, The control unit is Transmitting an instruction to supply air pressure to the brake mechanism for gentle braking so that the deceleration of the vehicle is performed by gentle braking with a deceleration rate that is not zero; supplying air pressure for the main braking to the brake mechanism so that the vehicle is decelerated by main braking having a deceleration degree greater in absolute value than that of the main braking when a predetermined time for the main braking has elapsed since transmitting an instruction to supply air pressure for the main braking, The control unit is configured to reduce the air pressure supplied to the brake mechanism when the vehicle speed becomes equal to or lower than a predetermined speed, The control unit is configured to allow the vehicle to return to normal running when a signal for releasing the emergency stop is input during the gentle braking. Pneumatic control device.

2. The control unit is configured to increase the reduced air pressure to a predetermined value or more after a predetermined time has elapsed since the vehicle became equal to or less than the predetermined speed. The pneumatic control device according to claim 1.

3. The control unit is configured to increase the air pressure supplied to the brake mechanism to a predetermined value or more after a predetermined time has elapsed since the air pressure has become equal to or lower than a lower limit pressure due to the reduction in air pressure. The pneumatic control device according to claim 1.

4. The control unit is configured to, when the air pressure supplied to the brake mechanism during deceleration of the vehicle becomes equal to or higher than an upper limit pressure, keep the air pressure supplied to the brake mechanism constant at the upper limit pressure. The air pressure control device according to any one of claims 1 to 3.

5. The control unit is configured to determine the air pressure to be supplied to the brake mechanism at predetermined time intervals. The air pressure control device according to any one of claims 1 to 4.

6. The pneumatic circuit is configured to supply air to the brake mechanism in place of a brake valve that supplies air to the brake mechanism when a brake operation is performed. The air pressure control device according to any one of claims 1 to 5.

7. The control unit is configured to supply air pressure for gentle braking to the brake mechanism when an abnormality signal indicating an abnormality due to operation of a passenger switch is acquired as a signal for bringing the vehicle to an emergency stop. The air pressure control device according to any one of claims 1 to 6.

8. the pneumatic circuit has a first port connected to an air tank of a vehicle, a second port connected to a brake valve that outputs an air pressure signal when a brake operation is performed, and a third port connected to a brake mechanism that applies a braking force to a wheel based on the air pressure signal, and is configured to switch between a first communication state in which air is supplied from the second port to the third port and a second communication state in which air is supplied from the first port to the third port, The control unit is configured to switch the air pressure circuit from the first communication state to the second communication state based on a signal for emergency stopping the vehicle. The air pressure control device according to any one of claims 1 to 7.

9. a pneumatic circuit configured to supply air to a brake mechanism that applies a braking force to a wheel; and a control unit configured to control the air pressure supplied from the pneumatic circuit to the brake mechanism, a deceleration step of supplying air to the brake mechanism based on a signal for bringing the vehicle to an emergency stop to decelerate the vehicle, the deceleration step including transmitting an instruction to supply air pressure for the gentle braking to the brake mechanism so that the deceleration of the vehicle is performed by gentle braking with a deceleration rate that is not zero, and, when a predetermined gentle braking time has elapsed since transmitting the instruction to supply air pressure for the gentle braking, supplying air pressure for the main braking to the brake mechanism so that the deceleration of the vehicle is performed by main braking with an absolute value of deceleration greater than that of the gentle braking; an air pressure reducing step of reducing the air pressure supplied to the brake mechanism when the vehicle speed during deceleration reaches or exceeds a predetermined speed, In the deceleration step, when a signal for releasing the emergency stop is input during the gentle braking, the vehicle can be returned to normal running. Pneumatic control method.

10. A pneumatic control program comprising: a pneumatic circuit configured to supply air to a brake mechanism that applies a braking force to a wheel; a control unit configured to control the air pressure supplied from the pneumatic circuit to the brake mechanism. a deceleration step of supplying air to the brake mechanism based on a signal for bringing the vehicle to an emergency stop to decelerate the vehicle, the deceleration step including transmitting an instruction to supply air pressure for the gentle braking to the brake mechanism so that the deceleration of the vehicle is performed by gentle braking with a deceleration rate that is not zero, and, when a predetermined gentle braking time has elapsed since transmitting the instruction to supply air pressure for the gentle braking, supplying air pressure for the main braking to the brake mechanism so that the deceleration of the vehicle is performed by main braking with an absolute value of deceleration greater than that of the gentle braking; an air pressure reducing step of reducing the air pressure supplied to the brake mechanism when the vehicle speed during deceleration reaches or exceeds a predetermined speed; In the deceleration step, when a signal for releasing the emergency stop is input during the gentle braking, the vehicle can be returned to normal running. Pneumatic control program.

Images