Brake system

Abstract

To provide a brake control device that securely generates wheel cylinder liquid pressure to all wheels FR-RR even at the time of failure of the brake control device, can securely decelerate / stop a vehicle, and has a simplified system configuration and high dependability for automatic operation.SOLUTION: A brake device 101 includes: a first liquid pressure unit 102p for supplying brake liquid to first wheel cylinders 118a, 118d; a second liquid pressure unit 102s for supplying brake liquid to second wheel cylinders 118b, 118c; and a connection pipe 119 for connecting the first liquid pressure unit and the second liquid pressure unit and circulating brake liquid. The first liquid pressure unit and the second liquid pressure unit open a first cut-out valve 104p and a second cut-out valve 104s when the failure of at least one of them is detected.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a brake control device compatible with automatic driving. [Background technology]

[0002] Regarding autonomous driving, according to the autonomous driving levels and responsibility allocation classifications stipulated in SAE J3016, control responsibility is placed on the system side at so-called Level 3 and above, and at Level 3, the driver has final operational responsibility in the event of a failure, but failure judgment and control transition are guaranteed by the system. Also, at Level 4 and above, all states are guaranteed by the system. Therefore, system components for autonomous driving must be highly reliable and must have redundancy to maintain functionality in the event of a failure.

[0003] Redundancy is also essential in brake control devices to ensure that the vehicle can be decelerated and stopped in the event of a malfunction, and Patent Document 1 discloses a brake control device equipped with two hydraulic control units (a first hydraulic control unit and a second hydraulic control unit) as a redundant configuration.

[0004] Here, the first hydraulic control unit has a first control unit (ECU), the second hydraulic control unit has a second control unit (ECU), and the shutoff valves that shut off communication between the master cylinder and the wheel cylinders connected to both units can be controlled by each of the two control units. Therefore, for example, if the first control unit determines that a failure has occurred in the second hydraulic control unit, the first control unit can control the shutoff valve in a closing direction to shut off communication between the master cylinder and the wheel cylinders. By controlling the actuator of the first hydraulic control unit as in the normal state, the target wheel cylinder hydraulic pressure for the front wheels FR, FL can be achieved, and the discharge hydraulic pressure of the pump of the first hydraulic control unit can be supplied not only to the wheel cylinders of the front wheels FR, FL, but also to the wheel cylinders 102 of the rear wheels RL, RR via hydraulic paths connecting the pump and the wheel cylinders of the rear wheels RL, RR (discharge hydraulic path 13A, connecting hydraulic path 11A (11PA, 11SA), relay hydraulic path 11I (11IS, 11IP), connecting hydraulic path 11B (11PB, 11SB), etc.).Therefore, wheel cylinder hydraulic pressure can be generated for all wheels FR to RR, and appropriate hydraulic pressure (= braking force) can be ensured. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-149998 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-mentioned conventional brake control devices, the shutoff valve is installed on the first hydraulic pressure control unit (first control unit) side. Therefore, if, for example, the first control unit fails and the shutoff valve itself becomes inoperable, the shutoff valve cannot be controlled in the closing direction even if the second hydraulic pressure control unit (second control unit) side is normal, and the pump discharge hydraulic pressure in the second hydraulic pressure control unit leaks into the master cylinder reservoir tank. As a result, the pump discharge hydraulic pressure cannot be supplied to the wheel cylinders of the front wheels FR, FL connected to the first hydraulic pressure control unit, as well as to the wheel cylinders of the rear wheels RL, RR connected directly to the second hydraulic pressure control unit. This makes it difficult to ensure appropriate hydraulic pressure.

[0007] Furthermore, in order to control a valve installed in one of the hydraulic control units (control units) from the other control unit, a new control unit configuration and a harness connecting both control units are required, which creates the problem of complicating the system configuration.

[0008] An object of the present invention is to provide a brake control device that is highly reliable for autonomous driving, capable of reliably generating wheel cylinder hydraulic pressure for all wheels FR to RR even in the event of such a failure, capable of reliably decelerating and stopping the vehicle, and has a simplified system configuration. [Means for solving the problem]

[0009] In order to solve the above problems, the brake control device of the present invention is a brake device mounted on a vehicle, and includes a first hydraulic pressure unit that supplies brake fluid to at least one first wheel cylinder, a second hydraulic pressure unit that supplies brake fluid to at least one second wheel cylinder, and a connecting pipe that connects the first hydraulic pressure unit and the second hydraulic pressure unit to circulate the brake fluid, the first hydraulic pressure unit has a first shut-off valve that blocks the flow of the brake fluid between the connecting pipe and a first control unit that controls the opening and closing of the first shut-off valve, the second hydraulic pressure unit has a second shut-off valve that blocks the flow of the brake fluid between the connecting pipe and a second control unit that controls the opening and closing of the second shut-off valve, and the first control unit and the second control unit open the first shut-off valve and the second shut-off valve, respectively, when a failure is detected in at least one of the first hydraulic pressure unit and the second hydraulic pressure unit. Effect of the Invention

[0010] According to the present invention, the two hydraulic units and the control units of each unit are separated, so that even if a failure occurs in one of the hydraulic units, the failure will not affect the other hydraulic unit. Therefore, the discharge hydraulic pressure from the other hydraulic unit can be supplied to the first wheel cylinder and the second wheel cylinder, making it possible to ensure braking force, thereby obtaining higher reliability. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating a configuration of a hydraulic control system 101 according to a first embodiment. [Diagram 2] FIG. 11 is a diagram illustrating a configuration of a hydraulic control system 201 according to a second embodiment. [Diagram 3] FIG. 11 is a diagram illustrating a configuration of a hydraulic control system 301 according to a third embodiment. [Figure 4] 4 is a flowchart showing a flow of brake control processing in a control unit in the first, second and third embodiments. [Diagram 5] FIG. 11 is a diagram illustrating a configuration of a hydraulic control system 401 according to a fourth embodiment. [Figure 6] FIG. 13 is a diagram showing the configuration of a hydraulic control system 501 according to a fifth embodiment. [Figure 7] 11 is a flowchart showing a flow of a brake control process in a control unit in the fourth and fifth embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] [Embodiment 1] FIG. 1 is a configuration diagram of a hydraulic control system 101 according to the first embodiment. The hydraulic control system 101 is a system intended for application mainly to Level 4 or higher autonomous vehicles, and constitutes a brake device mounted on the vehicle. In each part of FIG. 1, the suffix p of the reference symbol indicates that it corresponds to the primary system (P system) of the wheel cylinder 118. The suffix s of the reference symbol indicates that it corresponds to the secondary system (S system) of the wheel cylinder 118. Hereinafter, when the P and S systems are not distinguished, the p and s are omitted. The a suffix a of the reference symbol indicates that it corresponds to the left front wheel FL. Similarly, the b suffix c of the reference symbol indicates that it corresponds to the right front wheel FR, the c suffix d of the reference symbol indicates that it corresponds to the left rear wheel RL, and the d suffix d of the reference symbol indicates that it corresponds to the right rear wheel RR. When the wheels FL to RR are not distinguished, the a, b, c, and d symbols are omitted. The f suffix f of the reference symbol indicates that it corresponds to the front wheels FL / FR, and the r suffix r of the reference symbol indicates that it corresponds to the rear wheels RL / RR. When the front wheels and the rear wheels are not distinguished, the f and r symbols are omitted.

[0013] The hydraulic control system 101 generates brake hydraulic pressure (wheel cylinder hydraulic pressure) in the wheel cylinder (braking force application section) 118, thereby pressing the brake pads provided on each of the wheels FL to RR against the brake discs provided on the wheel side, thereby applying braking force to each of the wheels FL to RR.

[0014] The hydraulic control system 101 includes a first unit 102p and a second unit 102s. Each of the first unit 102p and the second unit 102s is a unit in which a pressure source 103, a shutoff valve 104, a pressure adjusting means 105, and an ECU 106 are integrally provided.

[0015] The first unit 102p and the second unit 102s have a unit connection port 113, a suction port 114, and a wheel cylinder port 115. The unit connection port 113 is connected to a unit connection pipe 119, and is connected to the shutoff valve 104 through a connection liquid path 111. The first unit 102p and the second unit 102s are also connected to each other through the unit connection pipe 119.

[0016] The suction port 114 is connected to a suction hose 116, and is connected to the pressure source 103 via a connecting fluid path 112. The first unit 102p and the second unit 102s are also connected to a reservoir tank 107 via the suction hose 116. The reservoir tank 107 is a brake fluid source that stores brake fluid, and is a low-pressure part that is released to atmospheric pressure.

[0017] Wheel cylinder port 115 is connected to wheel cylinder piping 117, and is connected to pressure adjusting means 105 via connecting fluid path 110. In addition, first unit 102p and second unit 102s are connected to wheel cylinder 118 via wheel cylinder piping 117. A so-called X (cross) piping configuration is adopted in which the primary system of first unit 102p is connected to left front wheel cylinder 118a and right rear wheel cylinder 118d, while the secondary system of second unit 102s is connected to right front wheel cylinder 118b and left rear wheel cylinder 118c. Note that H piping may be used, connecting the front wheels to the primary system and the rear wheels to the secondary system.

[0018] Moreover, the pressure source 103 and the pressure adjusting means 105 are connected via a connecting liquid path 108. Moreover, the shutoff valve 104 and the pressure adjusting means 105 are connected via a connecting liquid path 109.

[0019] Based on a command from an ECU 106 , the pressure source 103 draws in brake fluid stored in a reservoir tank 107 and discharges the required flow rate to a pressure adjusting means 105 .

[0020] The pressure regulating means 105 regulates the pressure of the brake fluid supplied from the pressure source 103 based on a command from the ECU 106, and outputs a desired pressure to the wheel cylinder 118 and the shutoff valve 104. Here, in the pressure regulating means 105, a connecting fluid path 109 and a connecting fluid path 110 are in communication with each other (not shown).

[0021] The shutoff valve 104 opens / closes based on a command from the ECU 106, and connects / disconnects the connecting fluid path 109 and the connecting fluid path 111. The shutoff valve 104 has a so-called normally open structure, and is open when there is no command (electrical signal) from the ECU 106 and no current is applied, i.e., the connecting fluid path 109 and the connecting fluid path 111 are in an open state (connected state).

[0022] The ECU 106 is an electronic control unit (ECU) that controls the first unit 102p and the second unit 102s, receives signals (target brake fluid pressures) from other ECUs, and controls the pressure source 103, the shutoff valve 104, and the pressure regulating means 105 as described above.

[0023] The wheel cylinders 118a and 118d of this embodiment correspond to the first wheel cylinder in the claims, the wheel cylinders 118b and 118c of this embodiment correspond to the second wheel cylinder in the claims, the first unit 102p and the second unit 102s of this embodiment correspond to the first hydraulic unit and the second hydraulic unit in the claims, and the unit connection pipe 119 of this embodiment corresponds to the connection pipe in the claims. The shutoff valves 104p and 104s of this embodiment correspond to the first shutoff valve and the second shutoff valve in the claims, and the ECUs 106p and 106s of this embodiment correspond to the first control unit and the second control unit in the claims. The pressure sources 103p and 103s of this embodiment correspond to the first pressure-feeding unit and the second pressure-feeding unit in the claims, and the pressure regulating means 105p and 105s of this embodiment correspond to the first pressure regulating unit and the second pressure regulating unit in the claims.

[0024] Next, the operation of the hydraulic control system 101 of the first embodiment will be described.

[0025] (Normal control when the system is normal) In the first unit 102p and the second unit 102s, the shutoff valve 104 is closed in response to a command from the ECU 106, and the connecting fluid path 109 is shut off from the connecting fluid path 111. In addition, the pressure source 103 and the pressure adjusting means 105 are controlled to output a desired pressure to the wheel cylinder 118, and a necessary braking force is applied to each of the wheels FL to RR of the wheel cylinder 118.

[0026] (Backup control in case of system failure) Here, as an example, a process performed by the ECU 106 when the second unit 102s fails (breaks down) will be described with reference to the flowchart of FIG.

[0027] In step S401, it is determined whether the second unit 102s is capable of hydraulic pressure control. This determination is made by the pressure source 103, the shutoff valve 104, the pressure adjusting means 105, and a failure detection logic (not shown) of the ECU 106, which are incorporated in the ECU 106. If it is determined that hydraulic pressure control is possible, the process proceeds to step S402, and if it is determined that hydraulic pressure control is not possible, i.e., a system failure, the process proceeds to step S403.

[0028] In step S402, normal control when the system is normal, as described above in

[0025] , is continued.

[0029] In step S403, the control shifts to backup control. That is, the shutoff valve 104p of the first unit 102p is opened. This operation connects the connecting fluid path 109p and the connecting fluid path 111p, and the pressure adjusted by the pressure adjusting means 105p is applied to the unit connecting port 113s of the second unit 102s via the unit connecting pipe 119 together with the wheel cylinders 118a / 118d.

[0030] Moreover, when the second unit 102s determines that the system has failed, the pressure source 103s, the shutoff valve 104s, and the pressure adjusting means 105s are deactivated (de-energized), the shutoff valve 104s is opened, and the connecting fluid path 109s and the connecting fluid path 111s are communicated with each other. In other words, when the ECUs 106p and 106s detect a failure of either the first unit 102p or the second unit 102s, they open the shutoff valves 104p and 104s, respectively.

[0031] Therefore, the pressure regulated by the pressure regulating means 105p of the first unit 102p is applied to the wheel cylinders 118b / 118c from the unit connection port 113s of the second unit 102s via the connecting liquid path 111s, the connecting liquid path 109s, the pressure regulating means 105s, the connecting liquid paths 110b / 110c, the wheel cylinder ports 115b / 115c, and the wheel cylinder piping 117b / 117c.

[0032] As a result, even if the second unit 102s fails, the desired pressure is output to the wheel cylinder 118, as in the case when the system is normal, and it is possible to apply the necessary braking force to each of the wheels FL to RR of the wheel cylinder 118.

[0033] Although the above is an example of the case where the second unit 102s fails, even if the first unit 102p fails, the operation itself is the same except that the first unit 102p and the second unit 102s are swapped in the processing of step S403 above.

[0034] Next, the effects of the first embodiment will be described. The hydraulic control system 101 of embodiment 1 has two units having the same configuration, a first unit 102p and a second unit 102s, where the first unit 102p has an ECU 106p and the second unit 102s has an ECU 106s. Each unit is provided with a shut-off valve 104 that is controlled only by the ECU 106 of each unit, and the upstream side (the side opposite the wheel cylinder) of the shut-off valve 104 provided in each unit is connected by a unit connection pipe 119.

[0035] Therefore, since the two units and the ECUs in each unit are separated, even if a malfunction occurs in one of the units or ECUs, the malfunction will not affect the other unit or ECU. Therefore, the discharge hydraulic pressure from the other unit can be supplied to all wheels, ensuring braking force and resulting in greater reliability.

[0036] In addition, the two units have the same configuration, and do not have a configuration in which the shutoff valve is controlled by two ECUs as shown in the prior art, so there is also the advantage that the system configuration is simplified.

[0037] [Embodiment 2] FIG. 2 is a configuration diagram of a hydraulic control system 201 according to the second embodiment. As with the first embodiment, this system is intended to be applied primarily to autonomous vehicles of Level 4 or higher.

[0038] The hydraulic control system 201 generates brake hydraulic pressure (wheel cylinder hydraulic pressure) in the wheel cylinder (braking force application section) 218, thereby pressing the brake pads provided on each of the wheels FL to RR against the brake discs provided on the wheel side, thereby applying braking force to each of the wheels FL to RR.

[0039] The hydraulic control system 201 includes a first unit 202p and a second unit 202s. Each of the first unit 202p and the second unit 202s is a unit in which a pressure source 203, a shutoff valve 204, a pressure adjusting means 205, and an ECU 206 are integrally provided.

[0040] The first unit 202p and the second unit 202s have a unit connection port 213, a suction port 214, and a wheel cylinder port 215.

[0041] The unit connection port 213 is connected to a unit connection pipe 219, and is connected to the shutoff valve 204 via a connection liquid path 211. In addition, the first unit 202p and the second unit 202s are connected to each other via the unit connection pipe 219.

[0042] The suction port 214 is connected to a suction hose 216, and is connected to a pressure source 203 via a connecting fluid path 212. The first unit 202p and the second unit 202s are connected to a reservoir tank 207 via the suction hose 216. In detail, the reservoir tank 207 is divided into two sections, and the primary fluid chamber 257p is connected to the first unit 202p, and the secondary fluid chamber 257s is connected to the second unit 202s. The reservoir tank 207 is a brake fluid source that stores brake fluid, and is a low-pressure section that is released to atmospheric pressure.

[0043] Wheel cylinder port 215 is connected to wheel cylinder piping 217, and is connected to pressure adjusting means 205 via connecting fluid path 210. In addition, first unit 202p and second unit 202s are connected to wheel cylinder 218 via wheel cylinder piping 217. A so-called X (cross) piping configuration is adopted in which the primary system of first unit 202p is connected to left front wheel cylinder 218a and right rear wheel cylinder 218d, while the secondary system of second unit 202s is connected to right front wheel cylinder 218b and left rear wheel cylinder 218c. Note that an H piping may be used that connects the front wheels to the primary system and the rear wheels to the secondary system.

[0044] Moreover, the pressure source 203 and the pressure adjusting means 205 are connected via a connecting liquid path 208. Moreover, the shutoff valve 204 and the pressure adjusting means 205 are connected via a connecting liquid path 209.

[0045] The pressure source 203 is composed of a pump 223 and a motor 233 that drives the pump. Based on a command from the ECU 206, the rotation of the motor 233 is controlled to suck in brake fluid stored in a reservoir tank 207 and discharge the required flow rate to the pressure adjusting means 205.

[0046] The pressure adjusting means 205 is composed of a pressure increase control valve 225, a pressure decrease control valve 235, a communication valve 245, a pressure sensor 255, and a pressure sensor 265, and adjusts the pressure of the brake fluid supplied from the pressure source 203 based on a command from the ECU 206. That is, the pressure detected by the pressure sensors 255 / 265 is fed back, and when increasing the pressure, the pressure increase control valve 225 is opened and the pressure decrease control valve 235 is closed, and when decreasing the pressure, the pressure increase control valve 225 is closed and the pressure decrease control valve 235 is opened, thereby obtaining a desired pressure. The adjusted pressure is output to the wheel cylinder 218 and to the shutoff valve 204 side by opening the communication valve 245.

[0047] The shutoff valve 204 opens / closes based on a command from the ECU 206, and connects / disconnects the connecting fluid path 209 and the connecting fluid path 211. The shutoff valve 204 has a so-called normally open structure, and is open when there is no command (electrical signal) from the ECU 206 and no current is applied, i.e., the connecting fluid path 209 and the connecting fluid path 211 are in an open state (connected state).

[0048] The ECU 206 is an electronic control unit (ECU) that controls the first unit 202p and the second unit 202s, receives signals (target brake fluid pressures) from other ECUs, and controls the pressure source 203, the shutoff valve 204, and the pressure regulating means 205 as described above.

[0049] Next, the operation of the hydraulic control system 201 of the second embodiment will be described.

[0050] (Normal control when the system is normal) In the first unit 202p and the second unit 202s, the shutoff valve 204 is closed in response to a command from the ECU 206, and the shutoff valve 204 shuts off communication between the connecting fluid path 209 and the connecting fluid path 211. In addition, the pressure source 203 and the pressure adjusting means 205 are controlled to output a desired pressure to the wheel cylinder 218, and a necessary braking force is applied to each of the wheels FL to RR of the wheel cylinder 218.

[0051] (Backup control in case of system failure) Here, as an example, a process performed by the ECU 206 when the second unit 202s fails will be described with reference to the flowchart of FIG.

[0052] In step S401, it is determined whether the second unit 202s can control the hydraulic pressure. This determination is made by the pressure source 203, the shutoff valve 204, the pressure adjusting means 205, and a failure detection logic (not shown) of the ECU 206, which are incorporated in the ECU 206. If it is determined that the hydraulic pressure can be controlled, the process proceeds to step S402, and if it is determined that the hydraulic pressure cannot be controlled, i.e., a system failure, the process proceeds to step S403.

[0053] In step S402, normal control when the system is normal, as described above in

[0050] , is continued.

[0054] In step S403, the control shifts to backup control. That is, the shutoff valves 204a / 204d of the first unit 202p are opened. This operation allows communication between the connecting fluid passage 209a and the connecting fluid passage 211a and between the connecting fluid passage 209d and the connecting fluid passage 211d, and the pressure regulated by the pressure regulating means 205a / 205d is applied to the unit connection ports 213b / 213c of the second unit 202s via the unit connection pipe 219 together with the wheel cylinders 218a / 218d.

[0055] In addition, when the second unit 202s determines that there is a system failure, the pressure source 203s, the shut-off valves 204b / 204c, and the pressure regulating means 205b / 205c become inoperative (non-energized), the shut-off valves 204b / 204c open, and communication is established between the connecting liquid path 209b and the connecting liquid path 211b, and between the connecting liquid path 209c and the connecting liquid path 211c.

[0056] Therefore, the pressure regulated by the pressure regulating means 205a / 205d of the first unit 202p is applied to the wheel cylinders 218b / 218c from the unit connection port 213b / 213c of the second unit 202s via the connecting liquid paths 211b / 211c, the connecting liquid paths 209b / 209c, the connecting liquid paths 210b / 210c, the wheel cylinder ports 215b / 215c, and the wheel cylinder piping 217b / 217c.

[0057] As a result, even if the second unit 202s fails, the desired pressure is output to the wheel cylinder 218, and the wheel cylinder 218 can apply the necessary braking force to each of the wheels FL to RR, in the same way as when the system is normal.

[0058] Although the above is an example of the case where the second unit 202s fails, even if the first unit 202p fails, the operation itself is the same except that the first unit 202p and the second unit 202s are swapped in the processing of step S403 above.

[0059] Next, the effects of the second embodiment will be described. The hydraulic control system 201 of embodiment 2 includes two units having the same configuration, a first unit 202p and a second unit 202s, where the first unit 202p has an ECU 206p and the second unit 202s has an ECU 206s. Each unit is provided with a shut-off valve 204 that is controlled only by the ECU 206 of each unit, and the upstream side (the side opposite the wheel cylinder) of the shut-off valve 204 provided in each unit is connected by a unit connection pipe 219.

[0060] Therefore, since the two units and the ECUs in each unit are separated, even if a malfunction occurs in one of the units or ECUs, the malfunction will not affect the other unit or ECU. Therefore, the discharge hydraulic pressure from the other unit can be supplied to all wheels, ensuring braking force and resulting in greater reliability.

[0061] In addition, the two units have the same configuration, and do not have a configuration in which the shutoff valve is controlled by two ECUs as shown in the prior art, so there is also the advantage that the system configuration is simplified.

[0062] [Embodiment 3] FIG. 3 is a configuration diagram of a hydraulic control system 301 according to the third embodiment. As with the first embodiment, this system is intended to be applied primarily to autonomous vehicles of Level 4 or higher. The basic configuration of the third embodiment is the same as that of the second embodiment, so only the differences from the second embodiment will be described.

[0063] The hydraulic control system 301 includes a first unit 302p and a second unit 302s. The first unit 302p and the second unit 302s are each a unit in which the pressure source 203, the shutoff valve 204, the pressure adjusting means 305, and the ECU 206 are integrally provided. Since the third embodiment is similar to the second embodiment except for the pressure adjusting means 305, the following describes the portion related to the pressure adjusting means 305.

[0064] The pressure adjusting means 305 is composed of a pressure increase control valve 325, a pressure reduction control valve 335, a communication valve 345, a pressure adjustment valve 385, and a pressure sensor 265, and adjusts the pressure of the brake fluid supplied from the pressure source 203 based on a command from the ECU 206. That is, the pressure detected by the pressure sensor 265 is fed back, and a first desired pressure is obtained by the pressure adjustment valve 385, and sent to the shutoff valve 204 side and the pressure increase control valve 325 side via the communication valve 345. Further, a second desired pressure is obtained by the pressure increase control valve 325 and the pressure reduction control valve 335, and output to the wheel cylinder 218.

[0065] The pressure increase control valve 325 and the pressure reduction control valve 335 in the pressure adjusting means 305 are operated only during vehicle behavior control such as ABS or ESC, and are not operated during normal braking when the vehicle behavior control is not involved. The pressure increase control valve 325 has a so-called normally open structure, and is open when there is no command (electrical signal) from the ECU 206 and no current is applied, i.e., the connecting fluid path 209 and the connecting fluid path 210 are in an open valve / communication state. The pressure reduction control valve 335 has a so-called normally closed structure, and is closed when there is no command (electrical signal) from the ECU 206 and no current is applied, i.e., the connecting fluid path 210 and the connecting fluid path 222 are in a closed valve / disconnection state.

[0066] Therefore, in the case of normal braking, the first desired pressure is output directly to the wheel cylinder 218 .

[0067] The ECU 206 is an electronic control unit (ECU) that controls the first unit 302p and the second unit 302s, receives signals (target brake fluid pressures) from other ECUs, and controls the pressure source 203, the shutoff valve 204, and the pressure regulating means 305 as described above.

[0068] Next, the operation of the hydraulic control system 301 of the third embodiment will be described.

[0069] (Normal control when the system is normal) In the first unit 302p and the second unit 302s, the shutoff valve 204 is closed in response to a command from the ECU 206, and the shutoff valve 204 shuts off communication between the connecting fluid path 209 and the connecting fluid path 211. In addition, the pressure source 203 and the pressure adjusting means 305 are controlled to output a desired pressure to the wheel cylinder 218, and a necessary braking force is applied to each of the wheels FL to RR of the wheel cylinder 218.

[0070] (Backup control in case of system failure) Here, as an example, a process performed by the ECU 206 when the second unit 302s fails will be described with reference to the flowchart of FIG.

[0071] In step S401, it is determined whether the second unit 302s can control the hydraulic pressure. This determination is made by the pressure source 203, the shutoff valve 204, the pressure adjusting means 305, and a failure detection logic (not shown) of the ECU 206, which are incorporated in the ECU 206. If it is determined that the hydraulic pressure can be controlled, the process proceeds to step S402, and if it is determined that the hydraulic pressure cannot be controlled, i.e., a system failure, the process proceeds to step S403.

[0072] In step S402, normal control when the system is normal, as described above in

[0069] , is continued.

[0073] In step S403, the control shifts to backup control. That is, the shutoff valves 204a / 204d of the first unit 302p are opened. This operation allows communication between the connecting fluid passage 209a and the connecting fluid passage 211a and between the connecting fluid passage 209d and the connecting fluid passage 211d, and the pressure (first desired pressure) adjusted by the pressure adjusting means 305p is applied to the unit connecting ports 213b / 213c of the second unit 302s via the unit connecting pipe 219 together with the wheel cylinders 218a / 218d.

[0074] When the second unit 302s determines that the system has failed, the pressure source 203s, the shutoff valves 204b / 204c, and the pressure adjusting means 305s are deactivated (de-energized), the shutoff valves 204b / 204c are opened, and the connecting liquid path 209b communicates with the connecting liquid path 211b and the connecting liquid path 209c communicates with the connecting liquid path 211c. Also, the connecting liquid path 209b communicates with the connecting liquid path 210b and the connecting liquid path 209c communicates with the connecting liquid path 210c.

[0075] Therefore, the pressure regulated by the pressure regulating means 305p of the first unit 302p is applied to the wheel cylinders 218b / 218c from the unit connection port 213b / 213c of the second unit 302s via the connecting liquid paths 211b / 211c, the connecting liquid paths 209b / 209c, the connecting liquid paths 210b / 210c, the wheel cylinder ports 215b / 215c, and the wheel cylinder piping 217b / 217c.

[0076] As a result, even if the second unit 302s fails, the desired pressure is output to the wheel cylinder 218, as in the case when the system is normal, and it is possible to apply the necessary braking force to each of the wheels FL to RR of the wheel cylinder 218.

[0077] Although the above is an example of the case where the second unit 302s fails, even if the first unit 302p fails, the operation itself is the same except that the first unit 302p and the second unit 302s are swapped in the processing of step S403 above.

[0078] Next, the effects of the third embodiment will be described. The hydraulic control system 301 of embodiment 3 includes two units having the same configuration, a first unit 302p and a second unit 302s, in which the first unit 302p has an ECU 206p and the second unit 302s has an ECU 206s. Each unit is provided with a shut-off valve 204 that is controlled only by the ECU 206 of each unit, and the upstream side (the side opposite the wheel cylinder) of the shut-off valve 204 provided in each unit is connected by a unit connection pipe 219.

[0079] Therefore, since the two units and the ECUs in each unit are separated, even if a malfunction occurs in one of the units or ECUs, the malfunction will not affect the other unit or ECU. Therefore, the discharge hydraulic pressure from the other unit can be supplied to all wheels, ensuring braking force and resulting in greater reliability.

[0080] In addition, the two units have the same configuration, and do not have a configuration in which the shutoff valve is controlled by two ECUs as shown in the prior art, so there is also the advantage that the system configuration is simplified.

[0081] [Embodiment 4] 5 is a configuration diagram of a hydraulic control system 401 according to embodiment 4. Unlike embodiments 1 to 3, the hydraulic control system 401 is a system intended for application to autonomous vehicles of Level 3 or higher, and is configured to take into consideration the application of braking force by the driver's brake pedal operation.

[0082] The hydraulic control system 401 generates brake hydraulic pressure (wheel cylinder hydraulic pressure) in the wheel cylinder (braking force application section) 418, thereby pressing the brake pads provided on each of the wheels FL to RR against the brake discs provided on the wheel side, thereby applying braking force to each of the wheels FL to RR.

[0083] The hydraulic control system 401 includes a first unit 402p and a second unit 402s. Each of the first unit 402p and the second unit 402s is a unit in which a pressure source 403, a shutoff valve 404, a pressure adjusting means 405, and an ECU 406 are integrally provided.

[0084] The vehicle also includes a brake pedal 460, a master cylinder 470, and a fail-safe unit 480. The master cylinder 470 is connected to the brake pedal 460.

[0085] The first unit 402p and the second unit 402s have a unit connection port 413, a suction port 414, and a wheel cylinder port 415.

[0086] The unit connection port 413 is connected to a unit connection pipe 419, and is connected to a shutoff valve 404 via a connecting liquid path 411. The first unit 402p and the second unit 402s are connected to each other via unit connection pipes 419p / 419s and connecting liquid paths 495p / 495s in a fail-safe unit 480.

[0087] The suction port 414 is connected to a suction hose 416, and is connected to a pressure source 403 via a connecting fluid path 412. The first unit 402p and the second unit 402s are also connected to a reservoir tank 407 via the suction hose 416. The reservoir tank 407 is a brake fluid source that stores brake fluid, and is a low-pressure part that is released to atmospheric pressure.

[0088] Wheel cylinder port 415 is connected to wheel cylinder piping 417, and is connected to pressure adjusting means 405 via connecting fluid path 410. In addition, first unit 402p and second unit 402s are connected to wheel cylinder 418 via wheel cylinder piping 417. A so-called X (cross) piping configuration is adopted in which the primary system of first unit 402p is connected to left front wheel cylinder 418a and right rear wheel cylinder 418d, while the secondary system of second unit 402s is connected to right front wheel cylinder 418b and left rear wheel cylinder 418c. Note that an H piping may be used that connects the front wheels to the primary system and the rear wheels to the secondary system.

[0089] Moreover, the pressure source 403 and the pressure adjusting means 405 are connected via a connecting liquid path 408. Moreover, the shutoff valve 404 and the pressure adjusting means 405 are connected via a connecting liquid path 409.

[0090] The brake pedal 460 receives the driver's depressing force and transmits the force to a master cylinder 470 .

[0091] Master cylinder 470 has a master cylinder body 471, a reservoir tank 477, and an output port 479. Master cylinder body 471 converts the force transmitted from brake pedal 460 into pressure. Reservoir tank 477 is a brake fluid source that stores brake fluid to be supplied to master cylinder body 471, and is a low-pressure part that is released to atmospheric pressure. Output port 479 is connected to master cylinder piping 491.

[0092] Fail-safe unit 480 has a backup shutoff valve 484, an ECU 486, a master cylinder port 493, and a unit connection port 496. Master cylinder port 493 is connected to master cylinder piping 491, and is connected to backup shutoff valve 484 via a connecting fluid path 494. Master cylinder 470 and fail-safe unit 480 are connected via master cylinder piping 491. Unit connection port 496 is connected to unit connection piping 419, and is connected to backup shutoff valve 484 via a connecting fluid path 495. As shown in FIG. 5, unit connection ports 496p / 496s are connected to connecting fluid paths 495p / 495s within fail-safe unit 480.

[0093] Based on a command from an ECU 406 , the pressure source 403 draws in brake fluid stored in a reservoir tank 407 and discharges the required flow rate to a pressure adjusting means 405 .

[0094] Based on a command from ECU 406, pressure regulating means 405 regulates the pressure of brake fluid supplied from pressure source 403 and outputs a desired pressure to wheel cylinder 418 and shutoff valve 404. Here, in pressure regulating means 405, connecting fluid path 409 and connecting fluid path 410 are in communication (not shown).

[0095] The shutoff valve 404 opens / closes based on a command from the ECU 406, and connects / disconnects the connecting liquid path 409 and the connecting liquid path 411. The shutoff valve 404 has a so-called normally open structure, and is open when there is no command (electrical signal) from the ECU 406 and no current is applied, i.e., the connecting liquid path 409 and the connecting liquid path 411 are in an open state (connected state).

[0096] The ECU 406 is an electronic control unit (ECU) that controls the first unit 402p and the second unit 402s, and receives signals (target brake fluid pressures) from other ECUs, and controls the pressure source 403, the shutoff valve 404, and the pressure adjusting means 405 as described above. Note that in this embodiment, the amount of operation of the brake pedal 460 by the driver, for example, the amount of operation may be detected by a pedal stroke sensor (not shown) or the like, and the target brake fluid pressure may be set based on this.

[0097] The backup cutoff valve 484 in the fail-safe unit 480 opens / closes based on a command from the ECU 486, and connects / disconnects the connecting fluid path 494 and the connecting fluid path 495. The backup cutoff valve 484 has a so-called normally open structure, and is open when there is no command (electrical signal) from the ECU 486 and when it is not energized, that is, the connecting fluid path 494 and the connecting fluid path 495 are in an open state (connected state).

[0098] The ECU 486 is an electronic control unit (ECU) that receives signals from other ECUs and controls the backup shutoff valve 484. The ECU 486 in this embodiment corresponds to a third control unit in the claims, and the backup shutoff valve 484 in this embodiment corresponds to a third shutoff valve in the claims.

[0099] Next, the operation of the hydraulic control system 401 of the fourth embodiment will be described.

[0100] (Normal control when the system is normal) In the first unit 402p and the second unit 402s, the shutoff valve 404 is closed by a command from the ECU 406 to shut off the connection between the connecting fluid path 409 and the connecting fluid path 411. In addition, the ECU 406 controls the pressure source 403 and the pressure adjusting means 405 to output a desired pressure to the wheel cylinder 418.

[0101] Furthermore, in the fail-safe unit 480, the backup cutoff valve 484 opens in response to a command from the ECU 486.

[0102] In this state, in the first unit 402p and the second unit 402s, the shut-off valves 404 are closed, so even if the backup shut-off valve 484 is open, the pressure regulated by the pressure regulating means 405 does not flow out to the master cylinder 470 (reservoir tank 477) side, making it possible to output the desired pressure to the wheel cylinder 418, and to apply the necessary braking force to each of the wheels FL to RR of the wheel cylinder 418.

[0103] (Backup control in case of system failure) Here, as an example, a process performed by the ECU 406 / ECU 486 when the second unit 402s fails will be described with reference to the flowchart of FIG.

[0104] In step S701, it is determined whether the second unit 402s can control the hydraulic pressure. This determination is made by the pressure source 403, the shutoff valve 404, the pressure adjusting means 405, and a failure detection logic (not shown) of the ECU 406, which are incorporated in the ECU 406. If it is determined that the hydraulic pressure can be controlled, the process proceeds to step S702, and if it is determined that the hydraulic pressure cannot be controlled, i.e., a system failure, the process proceeds to step S704.

[0105] In step S702, the first unit 402p and the second unit 402s continue normal control when the system is normal, as described above in

[0100] , and the process proceeds to step S703.

[0106] In step S703, as described in

[0100] above, the fail-safe unit 480 opens the backup shutoff valve 484. In this case, as described above, it becomes possible to output the desired pressure to the wheel cylinder 418, and it is possible to apply the necessary braking force to each of the wheels FL to RR of the wheel cylinder 418.

[0107] In step S704, the control shifts to backup control. That is, the shutoff valve 404p of the first unit 402p is opened. This operation allows the connecting fluid path 409p to communicate with the connecting fluid path 411p, and the pressure regulated by the pressure regulating means 405p is applied to the unit connection port 496p of the fail-safe unit 480 via the unit connection pipe 419p together with the wheel cylinders 418a / 418d.

[0108] In step S705, the backup cutoff valve 484 is closed in the fail-safe unit 480. This prevents the pressure regulated by the pressure regulating means 405p from flowing out to the master cylinder 470 (reservoir tank 477), and the pressure is applied from the unit connection port 496p of the fail-safe unit 480 to the unit connection port 413s of the second unit 402s via the connection fluid paths 495p / 495s, the unit connection port 496s, and the unit connection pipe 419s.

[0109] Furthermore, when the second unit 402s determines that there is a system failure, the pressure source 403s, the shutoff valve 404s, and the pressure adjusting means 405s are deactivated (de-energized), the shutoff valve 404s opens, and the connecting liquid path 409s and the connecting liquid path 411s communicate with each other.

[0110] Therefore, the pressure regulated by the pressure regulating means 405p of the first unit 402p is applied to the wheel cylinders 418b / 418c from the unit connection port 413s of the second unit 402s via the connecting liquid path 411s, the connecting liquid path 409s, the pressure regulating means 405s, the connecting liquid paths 410b / 410c, the wheel cylinder ports 415b / 415c, and the wheel cylinder piping 417b / 417c.

[0111] As a result, even if the second unit 402s fails, the desired pressure is output to the wheel cylinder 418, as in the case when the system is normal, and it is possible to apply the necessary braking force to each of the wheels FL to RR of the wheel cylinder 418.

[0112] Although the above is an example of the case where the second unit 402s fails, even if the first unit 402p fails, the operation itself is the same except that the first unit 402p and the second unit 402s are swapped in the processing of step S704 above.

[0113] (Braking force when all systems fail) In the hydraulic pressure control system 401, if all of the first unit 402p, the second unit 402s, and the fail-safe unit 480 fail due to, for example, a total power failure, the braking force is ensured by the driver's brake pedal operation in the following manner.

[0114] The driver's depressing force applied to the brake pedal 460 is transmitted to the master cylinder body 471 and converted into pressure. The pressure is applied from the output port 479 through the master cylinder piping 491 to the master cylinder port 493 of the fail-safe unit 480.

[0115] The backup cutoff valve 484 has a so-called normally open structure, and in a failed state, that is, when there is no command (electrical signal) from the ECU 486 and when it is not energized, it is open, that is, the connecting fluid path 494 and the connecting fluid path 495 are open and in communication. Therefore, the pressure applied to the master cylinder port 493 is applied from the unit connection port 496 through the unit connection pipe 419 to the unit connection port 413 of the first unit 402p and the second unit 402s. When the first unit 402p and the second unit 402s are in a failed state, the pressure source 403, the cutoff valve 404, and the pressure adjustment means 405 are inoperative (not energized) as described above, the cutoff valve 404 is open, and the connecting fluid path 409 and the connecting fluid path 411 are in communication. That is, when the ECU 486 detects failures in both the first unit 402p and the second unit 402s, it opens the backup cutoff valve 484.

[0116] Therefore, the pressure generated in master cylinder 470 by the driver's pedaling force is applied from unit connection port 413 through connecting fluid path 411, connecting fluid path 409, pressure regulating means 405, connecting fluid path 410, wheel cylinder port 415, and wheel cylinder piping 417 to wheel cylinder 418, making it possible to apply the necessary braking force to each of wheels FL to RR through wheel cylinder 418.

[0117] Next, the effects of the fourth embodiment will be described. The hydraulic control system 401 of the fourth embodiment includes a brake pedal 460, a master cylinder 470, a fail-safe unit 480, and two units having the same configuration, a first unit 402p and a second unit 402s, in which the first unit 402p has an ECU 406p and the second unit 402s has an ECU 106s. Each unit is provided with a shut-off valve 404 controlled only by the ECU 406 of each unit. The upstream side (the opposite side to the wheel cylinder) of the shut-off valve 404 provided in each unit is connected by a unit connecting pipe 419. A backup shut-off valve 484 controlled by an ECU 486 is provided between the unit connecting pipe 419 and the master cylinder 470.

[0118] Therefore, since these units and the ECUs possessed by each unit are separated, even if a failure occurs in the unit ECU of either the first unit 402p or the second unit 402s, the failure will not affect the other unit ECU. Furthermore, by closing the backup shut-off valve 484, pressure is prevented from leaking to the master cylinder 470 (reservoir tank 477) side, and the discharge hydraulic pressure from the other unit can be supplied to all wheels, making it possible to ensure braking force and thus obtaining higher reliability.

[0119] In addition, the first unit 402p and the second unit 402s have the same configuration, and do not have a configuration in which the shut-off valve is controlled from two ECUs as shown in the prior art, which has the advantage of simplifying the system configuration.

[0120] Furthermore, in this configuration, even if all of the first unit 402p, the second unit 402s, and the fail-safe unit 480 fail due to a total power failure or the like, the pressure generated in the master cylinder 470 by the driver's pedaling force is applied to the wheel cylinder 418, making it possible to apply the necessary braking force to each of the wheels FL to RR by the wheel cylinder 418, thereby ensuring even higher reliability.

[0121] [Embodiment 5] 6 is a configuration diagram of a hydraulic control system 501 according to embodiment 5. Unlike embodiments 1 to 3, the hydraulic control system 501 is a system intended for application to autonomous vehicles of Level 3 or higher, and is configured to take into consideration the application of braking force by the driver's brake pedal operation.

[0122] The hydraulic control system 501 generates brake hydraulic pressure (wheel cylinder hydraulic pressure) in the wheel cylinder (braking force application section) 518, thereby pressing the brake pads provided on each of the wheels FL to RR against the brake discs provided on the wheel side, thereby applying braking force to each of the wheels FL to RR.

[0123] The hydraulic control system 501 includes a first unit 502p and a second unit 502s. Each of the first unit 502p and the second unit 502s is a unit in which a pressure source 503, a shutoff valve 504, a pressure adjusting means 505, and an ECU 506 are integrally provided.

[0124] It also has a brake pedal 560, a master cylinder 570, and a fail-safe unit 580.

[0125] The first unit 502p and the second unit 502s have a unit connection port 513, a suction port 514, and a wheel cylinder port 515.

[0126] The unit connection port 513 is connected to a unit connection pipe 519, and is connected to a shutoff valve 504 via a connecting liquid path 511. The first unit 502p and the second unit 502s are connected to each other via unit connection pipes 519a / 519b, unit connection pipes 519c / 519d, connecting liquid paths 595a / 595b in the fail-safe unit 580, and connecting liquid paths 595c / 595d.

[0127] The suction port 514 is connected to a suction hose 516, and is connected to a pressure source 503 via a connecting fluid path 512. The first unit 502p and the second unit 502s are also connected to a fluid chamber 567 of a reservoir tank 577 via the suction hose 516. The reservoir tank 577 is a brake fluid source that stores brake fluid, and is a low-pressure section that is released to atmospheric pressure. The reservoir tank 577 is divided into three fluid chambers 557p / 557s / 567, and the fluid chambers 557p / 557s are connected to a master cylinder 570, which will be described later.

[0128] Wheel cylinder port 515 is connected to wheel cylinder piping 517, and connected to pressure regulating means 505 via connecting fluid path 510. In addition, first unit 502p and second unit 502s are connected to wheel cylinder 518 via wheel cylinder piping 517. A so-called X (cross) piping configuration is adopted in which the primary system of first unit 502p is connected to left front wheel cylinder 518a and right rear wheel cylinder 518d, while the secondary system of second unit 502s is connected to right front wheel cylinder 518b and left rear wheel cylinder 518c. Note that H piping may be used to connect the front wheels to the primary system and the rear wheels to the secondary system.

[0129] Moreover, the pressure source 503 and the pressure adjusting means 505 are connected via a connecting liquid path 508. Moreover, the shutoff valve 504 and the pressure adjusting means 505 are connected via a connecting liquid path 509.

[0130] Brake pedal 560 receives the force applied by the driver and transmits the force to master cylinder 570 via push rod 562 .

[0131] Master cylinder 570 has master cylinder body 571, reservoir tank 577, and output port 579. Master cylinder body 571 has piston 572 inside, converts force transmitted from brake pedal 560 into pressure, and outputs it to output port 579 from pressure chamber 573 via connecting fluid path 574. Reservoir tank 577 is a brake fluid source that stores brake fluid to be supplied to master cylinder body 571, and is a low-pressure section released to atmospheric pressure, and has fluid chambers 557p / 557s as described above, and supplies brake fluid to pressure chambers 573p / 573s, respectively. Output port 579 is connected to master cylinder piping 591.

[0132] A stroke simulator 563 is integrally provided with the master cylinder 570. The stroke simulator 563 operates in response to the driver's brake operation to generate a brake pedal feeling (feeling of pressure on the pedal). When the driver operates the brake pedal, a primary piston 572p of the master cylinder 570 moves, and the brake fluid pushed out by the movement flows into the stroke simulator 563 via a connecting fluid path 578 and an input port 568, and the simulator piston 564 is displaced, thereby generating a pedal stroke. A spring 566 is provided in contact with an end face of the simulator piston 564 on the side to which the brake fluid from the master cylinder 570 is not applied, and transmits a spring reaction force corresponding to the displacement of the simulator piston 564 to the simulator piston 564, and a pressure generated by the reaction force is transmitted to the primary piston 572p of the master cylinder 570, generating a pedal reaction force.

[0133] In addition, a stroke simulator cut valve 576 controlled by an ECU 586 in a fail-safe unit 580 is provided in the connecting fluid path 578 .

[0134] The fail-safe unit 580 has a backup shutoff valve 584, an ECU 586, a master cylinder port 593, and a unit connection port 596. The master cylinder port 593 is connected to a master cylinder pipe 591, and is connected to the backup shutoff valve 584 via a connecting fluid path 594. The master cylinder 570 and the fail-safe unit 580 are connected to each other via the master cylinder pipe 591. The unit connection port 596 is connected to a unit connection pipe 519, and is connected to the backup shutoff valve 584 via a connecting fluid path 595. As shown in FIG. 6, the unit connection ports 596a / 596b are connected to each other via connecting fluid paths 595a / 595b in the fail-safe unit 580, and the unit connection ports 596c / 596d are connected to each other via connecting fluid paths 595c / 595d in the fail-safe unit 580.

[0135] The pressure source 503 is composed of a pump 523 and a motor 533 that drives the pump. Based on a command from the ECU 506, the rotation of the motor 533 is controlled to suck in brake fluid stored in a reservoir tank 577 and discharge the required flow rate to the pressure adjusting means 505.

[0136] The pressure adjusting means 505 is composed of a pressure increase control valve 525, a pressure decrease control valve 535, a communication valve 545, a pressure sensor 555, and a pressure sensor 565, and adjusts the pressure of the brake fluid supplied from the pressure source 503 based on a command from the ECU 506. That is, the pressure detected by the pressure sensors 555 / 565 is fed back, and when increasing the pressure, the pressure increase control valve 525 is opened and the pressure decrease control valve 535 is closed, and when decreasing the pressure, the pressure increase control valve 525 is closed and the pressure decrease control valve 535 is opened, thereby obtaining a desired pressure. The adjusted pressure is output to the wheel cylinder 518 and the shutoff valve 504 by opening the communication valve 545.

[0137] The shutoff valve 504 opens / closes based on a command from the ECU 506, and connects / disconnects the connecting liquid path 509 and the connecting liquid path 511. The shutoff valve 504 has a so-called normally open structure, and is open when there is no command (electrical signal) from the ECU 506 and no current is applied, i.e., the connecting liquid path 509 and the connecting liquid path 511 are in an open state (connected state).

[0138] The ECU 506 is an electronic control unit (ECU) that controls the first unit 502p and the second unit 502s, and receives signals (target brake fluid pressures) from other ECUs, and controls the pressure source 503, the shutoff valve 504, and the pressure regulating means 505 as described above. Note that in this embodiment, the amount of operation of the brake pedal 560 by the driver, for example, the amount of operation may be detected by a pedal stroke sensor 561 or the like, and the target brake fluid pressure may be set based on this.

[0139] A stroke simulator cut valve 576 provided in the master cylinder 570 opens / closes based on a command from an ECU 586 in the fail-safe unit 580, and connects / disconnects a connecting fluid path 578, that is, connects / disconnects the master cylinder 570 and the stroke simulator 563. The stroke simulator cut valve 576 has a so-called normally closed structure, and is closed when there is no command (electrical signal) from the ECU 586 and when it is not energized, that is, the connection between the master cylinder 570 and the stroke simulator 563 is closed / disconnected.

[0140] The backup cutoff valve 584 in the fail-safe unit 580 opens / closes based on a command from the ECU 586, and connects / disconnects the connecting fluid path 594 and the connecting fluid path 595. The backup cutoff valve 584 has a so-called normally open structure, and is open when there is no command (electrical signal) from the ECU 586 and when it is not energized, that is, the connecting fluid path 594 and the connecting fluid path 595 are in an open state (connected state).

[0141] The ECU 586 is an electronic control unit (ECU) that receives signals from the other ECUs and controls the backup shutoff valve 584 and the stroke simulator cut valve 576 described above.

[0142] Next, the operation of the hydraulic control system 501 of the fifth embodiment will be described.

[0143] (Normal control when the system is normal) In the first unit 502p and the second unit 502s, the shutoff valve 504 is closed by a command from the ECU 506 to shut off the connection between the connecting fluid path 509 and the connecting fluid path 511. In addition, the pressure source 503 and the pressure adjusting means 505 are controlled to output a desired pressure to the wheel cylinder 518.

[0144] In the master cylinder 570, the stroke simulator cut valve 576 is opened in response to a command from the ECU 586.

[0145] Furthermore, in the fail-safe unit 580, the backup shutoff valve 584 is opened in response to a command from the ECU 586.

[0146] In this state, in the first unit 502p and the second unit 502s, the shut-off valve 504 is closed, so even if the backup shut-off valve 584 is open, the pressure regulated by the pressure regulating means 505 does not flow out to the master cylinder 570 (reservoir tank 577) side, and the desired pressure can be output to the wheel cylinder 518, and the necessary braking force can be applied to each of the wheels FL to RR of the wheel cylinder 518.

[0147] In addition, by communicating between the master cylinder 570 and the stroke simulator 563, a brake pedal feeling (feeling of resistance to pedaling) is generated in accordance with the brake operation by the driver.

[0148] (Backup control in case of system failure) Here, as an example, a process performed by the ECU 506 / ECU 586 when the second unit 502s fails will be described with reference to the flowchart of FIG.

[0149] In step S701, it is determined whether the second unit 502s can control the hydraulic pressure. This determination is made by the pressure source 503, the shutoff valve 504, the pressure adjusting means 505, and a failure detection logic (not shown) of the ECU 506, which are incorporated in the ECU 506. If it is determined that the hydraulic pressure can be controlled, the process proceeds to step S702, and if it is determined that the hydraulic pressure cannot be controlled, i.e., a system failure, the process proceeds to step S704.

[0150] In step S702, the first unit 502p and the second unit 502s continue normal control when the system is normal, as described above in

[0143] , and the process proceeds to step S703.

[0151] In step S703, as described in

[0143] above, the fail-safe unit 580 opens the backup shutoff valve 584. In this case, as described above, it becomes possible to output the desired pressure to the wheel cylinder 518, and it is possible to apply the necessary braking force to each of the wheels FL to RR of the wheel cylinder 518.

[0152] In step S704, the control shifts to backup control. That is, the shutoff valves 504a / 504d of the first unit 502p are opened. This operation allows communication between the connecting fluid passages 509a / 511a and between the connecting fluid passages 509d / 511d, and the pressure regulated by the pressure regulating means 505a / 505d is applied to the unit connection ports 596a / 596d of the fail-safe unit 580 via the unit connection pipes 519a / 519d together with the wheel cylinders 518a / 518d.

[0153] Furthermore, in the master cylinder 570, the stroke simulator cut valve 576 opens.

[0154] In step S705, the backup shutoff valves 584p / 584s are closed in the fail-safe unit 580. This prevents the pressure regulated by the pressure regulating means 505a / 505d from flowing out to the master cylinder 570 (reservoir tank 577) side, and the pressure is applied from the unit connection ports 596a / 596d of the fail-safe unit 580 to the unit connection ports 513b / 513c of the second unit 502s via the connection fluid paths 595a / 595b, the connection fluid paths 595c / 595d, the unit connection ports 596b / 596c, and the unit connection pipes 519b / 519c.

[0155] In addition, when the second unit 502s determines that there is a system failure, the pressure source 503s, the shut-off valves 504b / 504c, and the pressure regulating means 505b / 505c become inoperative (non-energized), the shut-off valves 504b / 504c open, and communication is established between the connecting liquid path 509b and the connecting liquid path 511b, and between the connecting liquid path 509c and the connecting liquid path 511c.

[0156] Therefore, the pressure regulated by the pressure regulating means 505a / 505d of the first unit 502p is applied to the wheel cylinders 518b / 518c from the unit connection ports 513b / 513c of the second unit 502s via the connecting liquid paths 511b / 511c, the connecting liquid paths 509b / 509c, the connecting liquid paths 510b / 510c, the wheel cylinder ports 515b / 515c, and the wheel cylinder piping 517b / 517c.

[0157] As a result, even if second unit 502s fails, the desired pressure is output to wheel cylinder 518, as in the case when the system is normal, and it is possible to apply the necessary braking force to each of wheels FL to RR of wheel cylinder 518. Furthermore, by communicating between the master cylinder 570 and the stroke simulator 563, a brake pedal feeling (feeling of resistance to pressure) is generated in response to the driver's brake operation, as in the case when the system is normal.

[0158] Although the above is an example of the case where the second unit 502s fails, even if the first unit 1502p fails, the operation itself is the same except that the first unit 502p and the second unit 502s are swapped in the processing of step S704 above.

[0159] (Braking force when all systems fail) In the hydraulic control system 501, for example, if all of the first unit 502p, the second unit 502s, the fail-safe unit 580, and the stroke simulator cut valve 576 provided in the master cylinder 570 fail due to a total power failure, the braking force is ensured by the driver's brake pedal operation using the following method.

[0160] The driver's depressing force applied to the brake pedal 560 is transmitted to the master cylinder body 571 via the push rod 562 and converted into pressure. The pressure is then passed from the output port 579 through the master cylinder piping 591 to the fail-safe unit 574. 580 The master cylinder port 593 is connected to the engine.

[0161] The stroke simulator cut valve 576 has a so-called normally closed structure, and when there is no command (electrical signal) from the ECU 586 and no current is applied, the valve is closed, i.e., the connection between the master cylinder 570 and the stroke simulator 563 is shut off. It is possible to prevent the brake fluid pushed out from the primary piston 572p of the master cylinder 570 by the driver's brake pedal operation from flowing into the stroke simulator 563, that is, to prevent a reduction in the amount of brake fluid supplied to the wheel cylinder 518 described below.

[0162] The backup cutoff valve 584 has a so-called normally open structure, and in a failed state, that is, when there is no command (electrical signal) from the ECU 586 and when it is not energized, it is open, that is, the connecting fluid path 594 and the connecting fluid path 595 are open and in communication. Therefore, the pressure applied to the master cylinder port 593 is applied from the unit connection port 596 through the unit connection pipe 519 to the unit connection port 513 of the first unit 502p and the second unit 502s. When the first unit 502p and the second unit 502s are in a failed state, the pressure source 503, the cutoff valve 504, and the pressure adjustment means 505 are inoperative (not energized) as described above, the cutoff valve 504 is open, and the connecting fluid path 509 and the connecting fluid path 511 are in communication.

[0163] Therefore, the pressure generated in master cylinder 570 by the driver's pedaling force is applied to wheel cylinder 518 from unit connection port 513 via connecting fluid path 511, connecting fluid path 509, connecting fluid path 510, wheel cylinder port 515, and wheel cylinder piping 517, making it possible to apply the necessary braking force to each wheel FL to RR through wheel cylinder 518.

[0164] Next, the effects of the fifth embodiment will be described. A hydraulic control system 501 of the fifth embodiment includes a brake pedal 560, a master cylinder 570, a fail-safe unit 580, a stroke simulator 563, and two units having the same configuration, a first unit 502p and a second unit 502s. The first unit 502p has an ECU 506p, and the second unit 502s has an ECU 506s. A shutoff valve 504 controlled only by the ECU 506 of each unit is provided in each unit. The upstream side (opposite the wheel cylinder) of the shutoff valve 504 provided in each unit is connected by a unit connecting pipe 519. An ECU is provided between the unit connecting pipe 519 and the master cylinder 570. 586 A backup shutoff valve 584 is provided that is controlled by

[0165] Therefore, since these units and the ECUs possessed by each unit are separated, even if a failure occurs in the unit ECU of either the first unit 502p or the second unit 502s, the failure will not affect the ECU of the other unit, and by closing the backup shut-off valve 584, pressure is prevented from leaking to the master cylinder 570 (reservoir tank 577) side, so that the discharge hydraulic pressure from the other unit can be supplied to all wheels and braking force can be ensured, resulting in higher reliability.

[0166] In addition, even during the failure, the stroke simulator 563 can generate a brake pedal feeling (feeling of pressure on the pedal) according to the driver's brake operation, just as when the system is normal.

[0167] In addition, the first unit 502p and the second unit 502s have the same configuration, and do not have a configuration in which the shut-off valve is controlled from two ECUs as shown in the prior art, which has the advantage of simplifying the system configuration.

[0168] Furthermore, in this configuration, even if all of the first unit 502p, the second unit 502s, the fail-safe unit 580, and the stroke simulator cut valve 576 provided in the master cylinder 570 fail due to a total power failure or the like, the pressure generated in the master cylinder 570 by the driver's pedaling force is applied to the wheel cylinder 518, making it possible to apply the necessary braking force to each of the wheels FL to RR of the wheel cylinder 518, thereby ensuring even higher reliability.

[0169] Other Embodiments The above describes an embodiment for carrying out the present invention, but the specific configuration of the present invention is not limited to the configuration of the embodiment, and design changes and the like that do not deviate from the gist of the invention are also included in the present invention.

[0170] For example, in the embodiment, the pressure source is described as being composed of a pump and a motor that drives the pump, but the pump may be any of a plunger pump, a rotary pump, etc., or may be an electric piston operated by an electric motor.

[0171] Although the embodiments of the present invention have been described above in detail, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the spirit of the present invention described in the claims. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those having all of the configurations described. In addition, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0172] 101 Hydraulic control system (brake device) 102p 1st unit (1st hydraulic unit) 102s 2nd unit (2nd hydraulic unit) 103p Pressure source (first pressure supply section) 103s Pressure source (second pressure supply section) 104p Shut-off valve (first shut-off valve) 104s Shut-off valve (second shut-off valve) 105p Pressure adjusting means (first pressure adjusting section) 105s Pressure adjusting means (second pressure adjusting section) 106p ECU (first control unit) 106s ECU (second control unit) 107 Reservoir Tank 118a, 118d Wheel cylinder (first wheel cylinder) 118b, 118c Wheel cylinder (second wheel cylinder) 119 Unit connection piping (connection piping) 460 Brake pedal 470 Master cylinder 480 Failsafe Unit 484 Backup shutoff valve (third shutoff valve) 486 ECU (3rd control unit) 491 Master cylinder piping

Claims

1. A brake device mounted on a vehicle, a first hydraulic unit that supplies brake fluid to at least one first wheel cylinder; a second hydraulic unit that supplies brake fluid to at least one second wheel cylinder; a connection pipe that connects the first hydraulic pressure unit and the second hydraulic pressure unit to allow the brake fluid to flow; having the first hydraulic pressure unit includes a first shutoff valve that shuts off the flow of the brake fluid between the first hydraulic pressure unit and the connecting pipe, a first control unit that controls opening and closing of the first shutoff valve, and a first pressure regulating unit that adjusts the hydraulic pressure of the brake fluid between the first hydraulic pressure unit and the connecting pipe, the second hydraulic pressure unit includes a second shutoff valve that shuts off the flow of the brake fluid between the second hydraulic pressure unit and the connecting pipe, a second control unit that controls opening and closing of the second shutoff valve, and a second pressure regulating unit that adjusts the hydraulic pressure of the brake fluid between the second hydraulic pressure unit and the connecting pipe, When the first control unit and the second control unit detect a failure of at least one of the first hydraulic pressure unit and the second hydraulic pressure unit, they open the first shutoff valve and the second shutoff valve, respectively; the first pressure regulating unit is connected to the first shutoff valve and the first wheel cylinder, and communicates with the connecting pipe and the second wheel cylinder by opening the first shutoff valve and the second shutoff valve, and the hydraulic pressure of the brake fluid adjusted by the first pressure regulating unit is applied to the second wheel cylinder, a second pressure regulating unit connected to the second shutoff valve and the second wheel cylinder, and communicating with the connecting pipe and the first wheel cylinder when the first shutoff valve and the second shutoff valve are opened, so that the hydraulic pressure of the brake fluid adjusted by the second pressure regulating unit is applied to the first wheel cylinder.

2. 2. The brake device according to claim 1, wherein the first hydraulic pressure unit and the second hydraulic pressure unit have the same configuration.

3. the first shutoff valve and the second shutoff valve are solenoid valves that shut off when energized, 2. The brake device according to claim 1, wherein, when a failure is detected in either the first hydraulic pressure unit or the second hydraulic pressure unit, the first control unit stops the supply of current to the first shutoff valve, and the second control unit stops the supply of current to the second shutoff valve.

4. 2. The brake device according to claim 1, wherein the first hydraulic unit has a first pressure-feeding portion that pumps the brake fluid.

5. 2. The brake device according to claim 1, wherein the second hydraulic unit has a second pressure-feeding portion that pumps the brake fluid.

6. A master cylinder connected to the brake pedal; a master cylinder pipe having one end connected to the master cylinder and the other end connected to the connecting pipe; a third shutoff valve disposed in the master cylinder pipe; A third control unit that controls opening and closing of the third shutoff valve, The third control unit is When both the first hydraulic unit and the second hydraulic unit are normal, the third shutoff valve is opened, when a failure of either the first hydraulic unit or the second hydraulic unit is detected, the third shutoff valve is shut off; 2. The brake device according to claim 1, wherein when a failure is detected in both the first hydraulic pressure unit and the second hydraulic pressure unit, the third shutoff valve is opened.

7. the third shutoff valve is an electromagnetic valve that is closed when energized and is opened when de-energized, 7. The brake device according to claim 6, wherein the supply of current to the third shutoff valve is stopped when both the first hydraulic pressure unit and the second hydraulic pressure unit are normal, or when failures are detected in both the first hydraulic pressure unit and the second hydraulic pressure unit.

Images