Braking device

Abstract

A processing circuit 81 of a braking device 40 determines whether or not an abnormality related to at least one of a first braking pressure and a second braking pressure has occurred. The processing circuit 81 determines whether or not two supply sources 421, 422 are operable. When the processing circuit 81 determines that an abnormality related to the first braking pressure or the second braking pressure has occurred, and determines that the two supply sources 421, 422 are not operable, the processing circuit 81 brings a switching unit 60 into a communication state. When the processing circuit 81 determines that an abnormality related to the first braking pressure or the second braking pressure has occurred, and determines that both of the two supply sources 421, 422 are operable, the processing circuit 81 brings the switching unit 60 into a cutoff state.

Description

Brake device

[0001] The present invention relates to a brake device that generates braking force for a vehicle by adjusting the hydraulic pressure of a wheel cylinder.

[0002] Patent Document 1 discloses a system including a first braking unit that adjusts the braking pressure of a first wheel cylinder and a second braking unit that adjusts the braking pressure of a second wheel cylinder. Each of the plurality of braking units includes a supply source of brake fluid and a sensor that detects the braking pressure. When an abnormality occurs in the detected pressure of the sensor of one of the plurality of braking units, the control device of the above system determines that the sensor is abnormal. In this case, the control device communicates a first liquid passage connected to the first wheel cylinder and a second liquid passage connected to the second wheel cylinder. When the vehicle brakes, the control device supplies brake fluid from two supply sources based on the detected pressure of the sensor of the other braking unit among the plurality of braking units.

[0003] Japanese Patent Application Laid-Open No. 2017-74891

[0004] When brake fluid is supplied from the supply source to the wheel cylinder in a situation where brake fluid leaks from the liquid passage or the wheel cylinder to the outside, even if the sensor is normal, the detected pressure of the sensor deviates from the hydraulic pressure corresponding to the supply amount of the brake fluid of the supply source. Therefore, in the above system, even when a brake fluid leak occurs, it is determined that an abnormality has occurred in the detected pressure. However, the subsequent countermeasures are different between the case where the sensor is abnormal and the case where a brake fluid leak has occurred.

[0005] An object of the present invention is to enable a countermeasure method according to the content of the occurrence of an abnormality.

[0006] A braking device for solving the above problems is applied to a vehicle equipped with a first wheel cylinder and a second wheel cylinder. The braking device includes a first supply source connected to the first wheel cylinder via a first fluid passage and adjusting the first braking pressure, which is the hydraulic pressure of the first wheel cylinder, by supplying brake fluid to the first fluid passage; a second supply source connected to the second wheel cylinder via a second fluid passage and adjusting the second braking pressure, which is the hydraulic pressure of the second wheel cylinder, by supplying brake fluid to the second fluid passage; and a switching unit that can switch between a communication state in which the first fluid passage and the second fluid passage are in communication and a disconnection state in which the communication between the first fluid passage and the second fluid passage is blocked. The braking device controls the braking force of the vehicle by operating the first supply source, the second supply source and the switching unit. The braking device includes: an abnormality determination unit that determines whether an abnormality has occurred with respect to at least one of the first braking pressure and the second braking pressure; an operation feasibility determination unit that determines whether the first supply source and the second supply source are operable; a first abnormality control unit that sets the switching unit to the communication state when the abnormality determination unit determines that an abnormality has occurred and the operation feasibility determination unit determines that either the first supply source or the second supply source is inoperable; and a second abnormality control unit that sets the switching unit to the shut-off state when the abnormality determination unit determines that an abnormality has occurred and the operation feasibility determination unit determines that both the first supply source and the second supply source are operable.

[0007] The above braking device has the effect of allowing for countermeasures to be taken according to the nature of the malfunction.

[0008] Figure 1 is a schematic diagram showing a vehicle equipped with a braking device according to the first embodiment. Figure 2 is a block diagram showing the functional configuration of the processing circuit included in the braking device of Figure 1. Figure 3 is a flowchart showing a series of processes performed by the processing circuit included in the braking device of Figure 1. Figure 4 is a flowchart showing a part of a series of processes performed by the processing circuit in the braking device of the second embodiment.

[0009] (First Embodiment) A first embodiment of the braking device will be described with reference to Figures 1 to 3. <Overall Vehicle Configuration> Figure 1 shows a vehicle 10 equipped with the braking device 40 of this embodiment. The vehicle 10 includes a plurality of wheels, a braking operating member 15, a plurality of friction brakes 20, and a plurality of sensors. The plurality of wheels include a left front wheel 11, a right front wheel 12, a left rear wheel 13, and a right rear wheel 14. The braking operating member 15 is a member operated by the driver of the vehicle 10 when adjusting the deceleration of the vehicle 10 during vehicle braking. An example of the braking operating member 15 is a brake pedal.

[0010] Multiple friction brakes 20 are individually provided for multiple wheels 11 to 14. Each friction brake 20 has a wheel cylinder, a rotating body 22, and a friction part 23. The rotating body 22 rotates integrally with the wheels 11 to 14. Therefore, by pressing the friction part 23 against the rotating body 22, a frictional braking force is generated on the wheels 11 to 14. The force pressing the friction part 23 against the rotating body 22 increases with higher hydraulic pressure in the wheel cylinder. Therefore, the friction brake 20 can generate a greater frictional braking force as the hydraulic pressure in the wheel cylinder increases.

[0011] Hereafter, the wheel cylinder corresponding to the left front wheel 11 will be referred to as "wheel cylinder 211". The wheel cylinder corresponding to the right front wheel 12 will be referred to as "wheel cylinder 212". The wheel cylinder corresponding to the left rear wheel 13 will be referred to as "wheel cylinder 213". The wheel cylinder corresponding to the right rear wheel 14 will be referred to as "wheel cylinder 214".

[0012] The hydraulic pressure inside the wheel cylinder is referred to as "braking pressure". The braking pressure of wheel cylinder 211 is "braking pressure Pw(1)". The braking pressure of wheel cylinder 212 is "braking pressure Pw(2)". The braking pressure of wheel cylinder 213 is "braking pressure Pw(3)". The braking pressure of wheel cylinder 214 is "braking pressure Pw(4)".

[0013] Multiple sensors each output a detection signal to a control device 80, which will be described later. The multiple sensors include, for example, a brake sensor 31. The brake sensor 31 detects the amount of operation of the driver's braking operation member 15.

[0014] <Configuration of the braking device> As shown in Figure 1, the braking device 40 comprises a plurality of braking units, a switching unit 60, a braking actuator 70, and a control device 80.

[0015] <Braking Unit> The multiple braking units include braking unit 411 and braking unit 412. Braking unit 411 generates frictional braking force at the left front wheel 11 by adjusting the braking pressure Pw(1). Braking unit 412 generates frictional braking force at the right front wheel 12 by adjusting the braking pressure Pw(2). In other words, braking unit 412 generates frictional braking force at a wheel different from the right rear wheel 14, which is located diagonally opposite the left front wheel 11 that generates frictional braking force by braking unit 411.

[0016] Braking unit 411 includes a supply source 421, a fluid passage 431, and a pressure sensor 441. Braking unit 412 includes a supply source 422, a fluid passage 432, and a pressure sensor 442.

[0017] Fluid passages 431 and 432 are fluid passages through which brake fluid flows. Fluid passage 431 is a fluid passage connecting the supply source 421 and the wheel cylinder 211. Fluid passage 432 is a fluid passage connecting the supply source 422 and the wheel cylinder 212.

[0018] The supply source 421 adjusts the braking pressure Pw(1) by supplying brake fluid to the wheel cylinder 211 via the fluid passage 431. The supply source 422 adjusts the braking pressure Pw(2) by supplying brake fluid to the wheel cylinder 212 via the fluid passage 432.

[0019] The pressure sensor 441 detects the braking pressure Pw(1). For example, the pressure sensor 441 is connected to the fluid passage 431. In this case, the pressure sensor 441 outputs a detection signal to the control device 80 corresponding to the fluid pressure in the fluid passage 431. The fluid pressure based on the detection signal from the pressure sensor 441 corresponds to the detected value of the braking pressure Pw(1), which is the "detected pressure PwS(1)".

[0020] The pressure sensor 442 detects the braking pressure Pw(2). For example, the pressure sensor 442 is connected to the fluid passage 432. In this case, the pressure sensor 442 outputs a detection signal to the control device 80 corresponding to the fluid pressure in the fluid passage 432. The fluid pressure based on the detection signal from the pressure sensor 442 corresponds to the detected value of the braking pressure Pw(2), which is the "detected pressure PwS(2)".

[0021] The multiple power sources 421, 422 include, for example, an electric cylinder 50. The electric cylinder 50 includes a cylinder 51, a piston 52, an electric motor 53, a conversion mechanism 54, a drive circuit, and a motor angle sensor. The piston 52 is slidably mounted within the cylinder 51. The conversion mechanism 54 converts the rotation of the output shaft of the electric motor 53 into the linear movement of the piston 52.

[0022] The drive circuits are the drive circuits for the electric motor 53. The drive circuit for the power source 421 is referred to as "drive circuit 551". The drive circuit for the power source 422 is referred to as "drive circuit 552". Drive circuits 551 and 552 drive the electric motor 53 by operating based on commands from the control device 80.

[0023] Inside the cylinder 51, a hydraulic chamber Re for storing brake fluid is partitioned by the peripheral wall of the cylinder 51 and the piston 52. The position of the piston 52 inside the cylinder 51 can be changed by driving the electric motor 53. Hereafter, the direction of linear movement of the piston 52 when reducing the volume of the hydraulic chamber Re will be described as the "forward direction Za," and the opposite direction of the forward direction Za will be described as the "reverse direction Zb." The reverse direction Zb is also the direction of linear movement of the piston 52 when increasing the volume of the hydraulic chamber Re.

[0024] Cylinder 51 has an output port 51p that connects the hydraulic chamber Re to the outside. The output port 51p is always open. A liquid passage 431 is connected to the output port 51p of the electric cylinder 50 of supply source 421. A liquid passage 432 is connected to the output port 51p of the electric cylinder 50 of supply source 422.

[0025] The motor angle sensor detects the rotation angle of the electric motor 53. The motor angle sensor of power source 421 is "motor angle sensor 561". The motor angle sensor of power source 422 is "motor angle sensor 562". Motor angle sensors 561 and 562 output a detection signal to the control device 80 in accordance with the change in the rotation angle of the electric motor 53. Hereafter, the rotation angle of the electric motor 53 based on the detection signals of motor angle sensors 561 and 562 will be referred to as "motor rotation angle θmt".

[0026] When the motor rotation angle θmt increases due to the drive of the electric motor 53, the piston 52 moves in the forward direction Za. As a result, the brake fluid in the hydraulic chamber Re is discharged into the fluid passages 431 and 432 via the output port 51p. This supplies brake fluid to the wheel cylinders 211 and 212, so the braking pressures Pw(1) and Pw(2) increase. On the other hand, when the motor rotation angle θmt decreases due to the drive of the electric motor 53, the piston 52 moves in the backward direction Zb. As a result, the brake fluid in the fluid passages 431 and 432 flows into the hydraulic chamber Re via the output port 51p. In this case, brake fluid flows out from the wheel cylinders 211 and 212, so the braking pressures Pw(1) and Pw(2) decrease.

[0027] <Switching section> The switching section 60 is configured to be switchable between a connected state in which liquid passage 431 and liquid passage 432 are connected, and a blocked state in which communication between liquid passage 431 and liquid passage 432 is blocked.

[0028] For example, the switching unit 60 has a connecting liquid passage 61 that connects liquid passage 431 and liquid passage 432, and a shut-off valve 62 installed in the connecting liquid passage 61. An example of the shut-off valve 62 is a normally open solenoid valve controlled by the control device 80. In this case, when the shut-off valve 62 is open, liquid passage 431 and liquid passage 432 communicate with each other via the connecting liquid passage 61. On the other hand, when the shut-off valve 62 is closed, communication between liquid passage 431 and liquid passage 432 is blocked by the shut-off valve 62. That is, the state of the switching unit 60 when the shut-off valve 62 is open is the communication state. On the other hand, the state of the switching unit 60 when the shut-off valve 62 is closed is the blocked state.

[0029] When the switching unit 60 is in the shut-off state, brake fluid supplied from the supply source 421 is supplied to the wheel cylinder 211 via the fluid passage 431. The section through which the brake fluid supplied from the supply source 421 flows in this manner is referred to as the "left front wheel system." The left front wheel system includes the supply source 421, the fluid passage 431, and the wheel cylinder 211. Similarly, when the switching unit 60 is in the shut-off state, brake fluid supplied from the supply source 422 is supplied to the wheel cylinder 212 via the fluid passage 432. The section through which the brake fluid supplied from the supply source 422 flows in this manner is referred to as the "right front wheel system." The right front wheel system includes the supply source 422, the fluid passage 432, and the wheel cylinder 212.

[0030] In this embodiment, the left front wheel 11 is an example of a "first wheel," and the right front wheel 12 is an example of a "second wheel." In this case, the wheel cylinder 211 for the left front wheel 11 corresponds to the "first wheel cylinder," and the wheel cylinder 212 for the right front wheel 12 corresponds to the "second wheel cylinder." The braking pressure Pw(1) of the wheel cylinder 211 corresponds to the "first braking pressure," and the braking pressure Pw(2) of the wheel cylinder 212 corresponds to the "second braking pressure." The fluid passage 431 connected to the wheel cylinder 211 corresponds to the "first fluid passage," and the fluid passage 432 connected to the wheel cylinder 212 corresponds to the "second fluid passage." The supply source 421 that supplies brake fluid to the fluid passage 431 corresponds to the "first supply source," and the supply source 422 that supplies brake fluid to the fluid passage 432 corresponds to the "second supply source."

[0031] <Braking Actuator> The braking actuator 70 operates to generate frictional braking force at the left rear wheel 13 and the right rear wheel 14. Specifically, the braking actuator 70 can generate frictional braking force at the right rear wheel 14, which is diagonally opposite the left front wheel 11. The braking actuator 70 can also generate frictional braking force at the left rear wheel 13, which is diagonally opposite the right front wheel 12.

[0032] The braking actuator 70 is configured to allow individual adjustment of the braking pressure Pw(3) of the wheel cylinder 213 for the left rear wheel 13 and the braking pressure Pw(4) of the wheel cylinder 214 for the right rear wheel 14. For example, the braking actuator 70 is equipped with a supply source that can supply brake fluid by driving an electric motor. An example of a supply source is an electric cylinder or an electric pump.

[0033] <Control device> The control device 80 includes a processing circuit 81. An example of the processing circuit 81 is an electronic control device. In this case, the processing circuit 81 includes a CPU 82, a first memory 83, and a second memory 84. The first memory 83 stores a control program executed by the CPU 82. The second memory 84 stores the calculation results of the CPU 82, etc. By the CPU 82 executing the control program in the first memory 83, the processing circuit 81 controls the supply sources 421, 422, the switching unit 60, and the braking actuator 70.

[0034] <Adjustment of braking pressures Pw(1) and Pw(2) with the switching unit shut off> The processing circuit 81 sets the target pressure PwTr(1), which is the target value of the braking pressure Pw(1). The processing circuit 81 then operates the supply source 421 so that the detected pressure PwS(1) follows the target pressure PwTr(1). For example, the processing circuit 81 derives the amount of brake fluid consumed Qf(1), which is the amount of brake fluid to be supplied to the wheel cylinder 211 in order to increase the braking pressure Pw(1) to the target pressure PwTr(1). The processing circuit 81 sets the motor rotation angle θmt to the target rotation angle θmtTr so that the amount of brake fluid supplied by the supply source 421 is equal to the amount of brake fluid consumed Qf(1). The processing circuit 81 drives the electric motor 53 so that the motor rotation angle θmt becomes the target rotation angle θmtTr. This allows the processing circuit 81 to make the detected pressure PwS(1) follow the target pressure PwTr(1).

[0035] Similarly, the processing circuit 81 sets a target pressure PwTr(2), which is the target value of the braking pressure Pw(2). The processing circuit 81 then operates the supply source 422 so that the detected pressure PwS(2) follows the target pressure PwTr(2). For example, the processing circuit 81 derives a fluid consumption amount Qf(2), which is the amount of brake fluid to be supplied to the wheel cylinder 212 in order to increase the braking pressure Pw(2) to the target pressure PwTr(2). The processing circuit 81 sets the motor rotation angle θmt to a target rotation angle θmtTr so that the amount of brake fluid supplied by the supply source 422 is equal to the fluid consumption amount Qf(2). The processing circuit 81 drives the electric motor 53 so that the motor rotation angle θmt becomes the target rotation angle θmtTr. As a result, the processing circuit 81 can make the detected pressure PwS(2) follow the target pressure PwTr(2).

[0036] <Adjustment of braking pressures Pw(1) and Pw(2) with the switching section in communication state> The processing circuit 81 sets a common target pressure PwTrF, which is a common target value for braking pressures Pw(1) and Pw(2). Then, the processing circuit 81 activates at least one of the multiple supply sources 421 and 422 based on the common target pressure PwTrF. For example, the processing circuit 81 derives a fluid consumption amount QfF, which is the sum of the amount of brake fluid to be supplied to the multiple wheel cylinders 211 and 212 in order to increase both braking pressures Pw(1) and Pw(2) to the common target pressure PwTrF. The processing circuit 81 sets the motor rotation angle θmt to a target rotation angle θmtTr, which is the motor rotation angle θmt that makes the sum of the brake fluid supplied by the supply sources 421 and 422 equal to the fluid consumption amount QfF. The processing circuit 81 drives the electric motor 53 so that the motor rotation angle θmt becomes the target rotation angle θmtTr. This allows the processing circuit 81 to make the detected pressures PwS(1) and PwS(2) follow the common target pressure PwTrF.

[0037] <Functional Units> Referring to Figure 2, the functional configuration of the processing circuit 81 will be explained. The processing circuit 81 has the function of switching the control mode of the braking device 40. The processing circuit 81 functions as a plurality of functional units for switching the control mode of the braking device 40 by having the CPU 82 execute the control program of the first memory 83. The plurality of functional units include an abnormality determination unit M11, an operation feasibility determination unit M13, and an abnormality control unit M20.

[0038] <Anomaly Determination Unit> The anomaly determination unit M11 determines whether or not an anomaly has occurred with respect to the braking pressure Pw(1) and the braking pressure Pw(2). Specifically, the anomaly determination unit M11 determines whether or not an anomaly has occurred with respect to the braking pressure Pw(1). The anomaly determination unit M11 determines whether or not an anomaly has occurred with respect to the braking pressure Pw(2). An example of an anomaly with respect to braking pressure is a discrepancy between the braking pressure and the predicted pressure.

[0039] An example of the process for determining whether or not such an abnormality related to braking pressure has occurred will be explained. The abnormality determination unit M11 generates the braking pressure Pw(1) of the wheel cylinder 211 by operating the supply source 421 when the switching unit 60 is in the shut-off state. At this time, the abnormality determination unit M11 derives the amount of brake fluid supplied from the electric cylinder 50 of the supply source 421. For example, the abnormality determination unit M11 derives that the amount of brake fluid supplied should be increased as the motor rotation angle θmt detected by the motor angle sensor 561 increases.

[0040] There is a correlation between the supply amount of the electric cylinder 50 and the braking pressure Pw(1). Therefore, the abnormality detection unit M11 refers to a map showing this correlation and derives the braking pressure Pw(1) corresponding to the supply amount as the predicted pressure Pwth(1).

[0041] Here, if brake fluid is leaking in the left front wheel system, or if there is a malfunction in the pressure sensor 441, or if the electric cylinder 50 of the supply source 421 is not operating properly, a discrepancy will occur between the detected pressure PwS(1) and the predicted pressure Pwth(1). On the other hand, if there is no brake fluid leaking in the left front wheel system, and the pressure sensor 441 is functioning normally, and the electric cylinder 50 is also operating normally, there will be almost no discrepancy between the detected pressure PwS(1) and the predicted pressure Pwth(1).

[0042] Therefore, when the magnitude of the difference between the braking pressure Pw(1) and the predicted pressure Pwth(1) is within the allowable range, the abnormality determination unit M11 determines that no abnormality has occurred in the braking pressure Pw(1). On the other hand, when the magnitude of the difference exceeds the allowable range, the abnormality determination unit M11 determines that an abnormality has occurred in the braking pressure Pw(1).

[0043] Note that the content of the determination process for whether an abnormality has occurred in the braking pressure Pw(2) is the same as the content of the determination process for whether an abnormality has occurred in the braking pressure Pw(1). Therefore, a detailed description of the determination process for whether an abnormality has occurred in the braking pressure Pw(2) will be omitted.

[0044] Hereinafter, when the abnormality determination unit M11 determines that no abnormality has occurred in the braking pressure, it is described as "the abnormality determination unit M11 determines that the braking pressure is normal". For example, "when the abnormality determination unit M11 determines that no abnormality has occurred in the braking pressure Pw(1)", it is described as "the abnormality determination unit M11 determines that the braking pressure Pw(1) is normal".

[0045] <Operation feasibility determination unit> The operation feasibility determination unit M13 determines whether a plurality of supply sources 421 and 422 are operable. That is, the operation feasibility determination unit M13 determines whether the supply source 421 is operable. The operation feasibility determination unit M13 determines whether the supply source 422 is operable. The operation feasibility determination unit M13 determines that the supply sources 421 and 422 are operable when the brake fluid can be appropriately supplied from the supply sources 421 and 422 to the liquid paths 431 and 432. On the other hand, the operation feasibility determination unit M13 determines that the supply sources 421 and 422 are inoperable when the brake fluid cannot be appropriately supplied from the supply sources 421 and 422 to the liquid paths 431 and 432.

[0046] As described above, the supply sources 421 and 422 include an electric cylinder 50. The electric cylinder 50 can supply brake fluid by driving the electric motor 53 using the motor rotation angle θmt which is the detected value of the motor angle sensors 561 and 562. Also, when the pressure sensors 441 and 442 are abnormal, even if brake fluid is being supplied from the electric cylinder 50, the pressure sensors 441 and 442 cannot detect changes in the braking pressures Pw(1) and Pw(2) resulting from the supply of brake fluid.

[0047] Therefore, the operation availability determination unit M13 determines that the supply sources 421 and 422 are inoperable when at least one of the following conditions (A1) to (A4) is satisfied. On the other hand, the operation availability determination unit M13 determines that the supply sources 421 and 422 are operable when none of the following conditions (A1) to (A4) is satisfied.

[0048] (A1) The motor angle sensors 561 and 562 are abnormal. (A2) An abnormality has occurred in the electric motor 53. For example, the current value of the electric motor 53 is an abnormal value.

[0049] (A3) An abnormality has occurred in the drive circuits 551 and 552. (A4) The pressure sensors 441 and 442 are abnormal. <Abnormality control unit> When the abnormality determination unit M11 determines that an abnormality has occurred, the abnormality control unit M20 adjusts at least one of the plurality of braking pressures Pw(1) and Pw(2) by operating at least one of the plurality of supply sources 421 and 422 and the switching unit 60. The abnormality control unit M20 includes a first abnormality control unit M21 and a second abnormality control unit M22.

[0050] <First abnormality control unit> In the present embodiment, when the abnormality determination unit M11 determines that an abnormality has occurred and the operation availability determination unit M13 determines that the supply source 421 or the supply source 422 is inoperable, it is considered that no brake fluid leakage has occurred in either the left front wheel system or the right front wheel system.

[0051] Therefore, the first abnormality control unit M21 connects the switching unit 60 when the abnormality determination unit M11 determines that an abnormality has occurred and the operation feasibility determination unit M13 determines that either the supply source 421 or the supply source 422 is inoperable. The first abnormality control unit M21 then adjusts the braking pressures Pw(1) and Pw(2) by activating one of the supply sources 421 and 422 that has not been determined to be inoperable by the operation feasibility determination unit M13.

[0052] <Second Abnormality Control Unit> In this embodiment, if the abnormality determination unit M11 determines that an abnormality has occurred, and the operation feasibility determination unit M13 determines that both of the multiple supply sources 421 and 422 are operational, it is assumed that brake fluid leakage has occurred in at least one of the left front wheel system and the right front wheel system. For example, if the abnormality determination unit M11 determines that an abnormality has occurred regarding the braking pressure Pw(1), it is assumed that brake fluid leakage has occurred in the left front wheel system. If the abnormality determination unit M11 determines that an abnormality has occurred regarding the braking pressure Pw(2), it is assumed that brake fluid leakage has occurred in the right front wheel system.

[0053] Therefore, the second abnormality control unit M22 shuts off the switching unit 60 when the abnormality determination unit M11 determines that an abnormality has occurred and the operation feasibility determination unit M13 determines that both of the multiple supply sources 421 and 422 are operational.

[0054] For example, if the abnormality determination unit M11 determines that only braking pressure Pw(1) is normal among multiple braking pressures Pw(1) and Pw(2), the second abnormality control unit M22 adjusts braking pressure Pw(1) by activating the supply source 421. In this case, the second abnormality control unit M22 prohibits the operation of the supply source 422.

[0055] Conversely, if the abnormality determination unit M11 determines that only braking pressure Pw(2) is normal among the multiple braking pressures Pw(1) and Pw(2), the second abnormality control unit M22 adjusts the braking pressure Pw(2) by activating the supply source 422. In this case, the second abnormality control unit M22 prohibits the operation of the supply source 421.

[0056] Furthermore, when the second abnormality control unit M22 determines that an abnormality has occurred by the abnormality determination unit M11 and that both of the multiple supply sources 421 and 422 are operational, and the vehicle 10 is to generate friction braking force, the second abnormality control unit M22 activates the braking actuator 70 to generate friction braking force on the rear wheel located diagonally opposite the front wheel that generates the friction braking force, out of the two front wheels 11 and 12.

[0057] For example, when the switching unit 60 is in a closed state and frictional braking force is generated only on the left front wheel 11 of the two front wheels 11 and 12, the second abnormal control unit M22 operates the braking actuator 70 so that frictional braking force is generated on the right rear wheel 14, which is located diagonally opposite the left front wheel 11. At this time, the second abnormal control unit M22 may generate frictional braking force on the left rear wheel 13, or it may not generate frictional braking force on the left rear wheel 13.

[0058] <Braking process in case of abnormality> Referring to Figure 3, an example of a series of processes executed by the processing circuit 81 when a braking request occurs will be explained. The series of processes shown in Figure 3 constitutes the braking process. This braking process shows the flow of processing when some abnormality occurs in the braking unit 411 or braking unit 412 when the braking device 40 starts operating in accordance with the braking request.

[0059] In Figure 3, "N" and "M" are either 1 or 2. For example, if "N" is 1, then "M" is 2, and if "N" is 2, then "N" is 1. First, we will explain the case where "N" is 1 and "M" is 2.

[0060] In step S11, the processing circuit 81 functions as an abnormality determination unit M11 to determine whether or not an abnormality has occurred with respect to the braking pressure Pw(1) corresponding to the first braking pressure. For example, the processing circuit 81 operates both of the two supply sources 421 and 422 in accordance with the braking request and then determines whether or not an abnormality has occurred with respect to the braking pressure Pw(1). At this point, the switching unit 60 may be in a connected state or in a disconnected state. If the processing circuit 81 determines that an abnormality has occurred with respect to the braking pressure Pw(1) corresponding to the first braking pressure (S11: YES), the processing circuit 81 proceeds to step S13. On the other hand, if the processing circuit 81 determines that no abnormality has occurred with respect to the braking pressure Pw(1) (S11: NO), the processing circuit 81 terminates the series of processes shown in Figure 3.

[0061] In step S13, the processing circuit 81 functions as an operation feasibility determination unit M13 to determine whether the supply source 421 corresponding to the first supply source is inoperable or not. If the processing circuit 81 determines that the supply source 421 corresponding to the first supply source is inoperable (S13: YES), the processing circuit 81 proceeds to step S15. On the other hand, if the processing circuit 81 determines that the supply source 421 is operable (S13: NO), the processing circuit 81 proceeds to step S21.

[0062] In step S15, the processing circuit 81 functions as an operation feasibility determination unit M13 to determine whether the supply source 422 corresponding to the second supply source is inoperable or not. If the processing circuit 81 determines that the supply source 422 corresponding to the second supply source is inoperable (S15: YES), the processing circuit 81 terminates the series of processes shown in Figure 3. On the other hand, if the processing circuit 81 determines that the supply source 422 is operable (S15: NO), the processing circuit 81 proceeds to step S17.

[0063] In step S17, the processing circuit 81 functions as the first abnormality control unit M21, thereby opening the switching unit 60. Specifically, the processing circuit 81 opens the shut-off valve 62 of the switching unit 60.

[0064] In the following step S19, the processing circuit 81 functions as the first abnormality control unit M21 to perform the first abnormality braking control. In this first abnormality braking control, the processing circuit 81 adjusts the braking pressures Pw(1) and Pw(2) of the two wheel cylinders 211 and 212 by stopping the operation of the supply source 421 and activating the supply source 422. That is, the processing circuit 81 generates frictional braking force at the two front wheels 11 and 12 by controlling the supply source 422.

[0065] In this case, the processing circuit 81 may generate frictional braking force on the two rear wheels 13 and 14 by activating the braking actuator 70. After that, when there is no longer a braking request, the processing circuit 81 terminates the first abnormal braking control and ends the series of processes shown in Figure 3.

[0066] In step S21, the processing circuit 81 functions as an operation feasibility determination unit M13 to determine whether the supply source 422 corresponding to the second supply source is inoperable or not. If the processing circuit 81 determines that the supply source 422 corresponding to the second supply source is inoperable (S21: YES), the processing circuit 81 terminates the series of processes shown in Figure 3. On the other hand, if the processing circuit 81 determines that the supply source 422 is operable (S21: NO), the processing circuit 81 proceeds to step S23.

[0067] In step S23, the processing circuit 81 functions as the second abnormality control unit M22, thereby shutting off the switching unit 60. Specifically, the processing circuit 81 closes the shut-off valve 62 of the switching unit 60.

[0068] In the following step S25, the processing circuit 81 functions as an abnormality determination unit M11 to determine whether or not an abnormality has occurred with respect to the braking pressure Pw(1) corresponding to the first braking pressure. At this point, the switching unit 60 is in the shut-off state. If the processing circuit 81 determines that an abnormality has occurred with respect to the braking pressure Pw(1) corresponding to the first braking pressure (S25: YES), the processing circuit 81 proceeds to step S27. On the other hand, if the processing circuit 81 determines that no abnormality has occurred with respect to the braking pressure Pw(1) (S25: NO), the processing circuit 81 terminates the series of processes shown in Figure 3. Note that if the switching unit 60 was in the shut-off state at the time of the determination in step S11, the processing circuit 81 may omit the determination process in step S25.

[0069] In step S27, the processing circuit 81 functions as an abnormality determination unit M11 to determine whether the braking pressure Pw(2) corresponding to the second braking pressure is normal or not. If the processing circuit 81 determines that the braking pressure Pw(2) corresponding to the second braking pressure is normal (S27: YES), the processing circuit 81 proceeds to step S29. On the other hand, if the processing circuit 81 determines that the braking pressure Pw(2) is not normal (S27: NO), the processing circuit 81 terminates the series of processes shown in Figure 3.

[0070] In step S29, the processing circuit 81 functions as the second abnormality control unit M22 to perform the second abnormal braking control. In this case, with the switching unit 60 in a shut-off state, an abnormality has occurred only with respect to the braking pressure Pw(1) corresponding to the first braking pressure among the two braking pressures Pw(1) and Pw(2). Furthermore, both the supply source 421 corresponding to the first supply source and the supply source 422 corresponding to the second supply source are operational. Therefore, the processing circuit 81 can determine that a brake fluid leak has occurred in the left front wheel system. For this reason, in the second abnormal braking control, the processing circuit 81 activates the supply source 422 while stopping the operation of the supply source 421. As a result, the processing circuit 81 adjusts the braking pressure Pw(2). Since the braking pressure Pw(2) is the braking pressure of the wheel cylinder 212 for the right front wheel 12, the processing circuit 81 controls the supply source 422 to generate frictional braking force only on the right front wheel 12 of the two front wheels 11 and 12.

[0071] In this case, the processing circuit 81 activates the braking actuator 70 to generate frictional braking force on the left rear wheel 13, which is located diagonally opposite the right front wheel 12, where frictional braking force is generated, among the two front wheels 11 and 12.

[0072] If a braking request is received, the processing circuit 81 continues to perform the second abnormal braking control. When the braking request ceases, the processing circuit 81 terminates the second abnormal braking control and ends the series of processes shown in Figure 3.

[0073] The first pattern, in which "N" is 1 and "M" is 2, has been described above. The second pattern, in which "N" is 2 and "M" is 1, may also be executed by the processing circuit 81. The processing flow in this case is approximately the same as in the first pattern. That is, if an abnormality occurs in the braking pressure Pw(2) corresponding to the second braking pressure, and the supply source 422 corresponding to the second supply source is inoperable, while the supply source 421 corresponding to the first supply source is operable, the processing circuit 81 opens the switching unit 60 and executes the first abnormal braking control. In this first abnormal braking control, the processing circuit 81 adjusts the braking pressures Pw(1) and Pw(2) of the two wheel cylinders 211 and 212 by activating the supply source 421.

[0074] Furthermore, if an abnormality occurs in the braking pressure Pw(2) corresponding to the second braking pressure, and the supply source 422 corresponding to the second supply source is operational, while the braking pressure Pw(1) corresponding to the first braking pressure is normal and the supply source 421 corresponding to the first supply source is operational, the processing circuit 81 shuts off the switching unit 60 and then performs the second abnormal braking control. In this second abnormal braking control, the processing circuit 81 adjusts the braking pressure Pw(1) by operating the supply source 421 while stopping the operation of the supply source 422. Since the braking pressure Pw(1) is the braking pressure of the wheel cylinder 211 for the left front wheel 11, the processing circuit 81 controls the supply source 421 to generate frictional braking force only on the left front wheel 11 of the two front wheels 11 and 12. In this case, the processing circuit 81 activates the braking actuator 70 to generate frictional braking force at the right rear wheel 14, which is located diagonally opposite the left front wheel 11 where frictional braking force is generated.

[0075] Furthermore, if both of the two power sources 421 and 422 are inoperable, the processing circuit 81 stops the operation of the two power sources 421 and 422 and then activates the braking actuator 70 to generate frictional braking force on the two rear wheels 13 and 14. Similarly, if an abnormality occurs regarding the braking pressure Pw(1) or the braking pressure Pw(2), the processing circuit 81 stops the operation of the two power sources 421 and 422 and then activates the braking actuator 70 to generate frictional braking force on the two rear wheels 13 and 14.

[0076] <Operation and Effects of this Embodiment> (1-1) If it is determined that an abnormality has occurred in relation to the braking pressure Pw(1), and it is also determined that the supply source 421 is inoperable, then it can be assumed that an abnormality has occurred in relation to the braking pressure Pw(1) because the supply source 421 cannot supply brake fluid normally. In other words, it can be assumed that no brake fluid leakage has occurred in the left front wheel system.

[0077] If it is determined that an abnormality has occurred regarding the braking pressure Pw(2), and that the supply source 422 is inoperable, then it can be assumed that an abnormality has occurred regarding the braking pressure Pw(2) because the supply source 422 cannot properly supply brake fluid. In other words, it can be assumed that there is no brake fluid leakage in the right front wheel system.

[0078] Therefore, if the processing circuit 81 determines that an abnormality has occurred in only one of the two braking pressures Pw(1) and Pw(2), and that the power source of the system in which the abnormality has occurred is inoperable, it sets the switching unit 60 to a communication state. As a result, the processing circuit 81 can generate frictional braking force on the two front wheels 11 and 12 by activating the power source among the multiple power sources 421 and 422 that it has determined is not inoperable.

[0079] If it is determined that an abnormality has occurred regarding the braking pressure Pw(1), and that the supply source 421 is operational, then it means that an abnormality has occurred regarding the braking pressure Pw(1) despite the supply source 421 being able to supply brake fluid normally. In this case, there is a possibility that brake fluid is leaking from the left front wheel system.

[0080] If it is determined that an abnormality has occurred regarding the braking pressure Pw(2), and that the supply source 422 is operational, then it means that an abnormality has occurred regarding the braking pressure Pw(2) despite the supply source 422 being able to supply brake fluid normally. In this case, there is a possibility that brake fluid is leaking from the right front wheel system.

[0081] Therefore, if the processing circuit 81 determines that an abnormality has occurred in only one of the two braking pressures Pw(1) and Pw(2), and that both of the two supply sources 421 and 422 are operational, it shuts off the switching unit 60. In other words, if there is a possibility of brake fluid leakage in the left front wheel system or the right front wheel system, the communication between fluid passage 431 and fluid passage 432 is shut off. This prevents the amount of brake fluid leakage from increasing.

[0082] When a braking request occurs while the switching unit 60 is in the shut-off state, the processing circuit 81 activates only the supply source of the system in which no brake fluid leakage has occurred among the two supply sources 421 and 422, thereby generating frictional braking force on only one of the two front wheels 11 and 12.

[0083] Therefore, the braking system 40 can take countermeasures according to the nature of the abnormality. Specifically, the braking system 40 can take different countermeasures depending on whether there is a possibility of brake fluid leakage or not.

[0084] (1-2) For example, if brake fluid leakage occurs in the left front wheel system or the right front wheel system, and frictional braking force is generated by only one of the two front wheels 11, 12, a difference in braking force between the left and right sides may occur, causing the moving vehicle 10 to deviate.

[0085] Therefore, when a braking request occurs while the switching unit 60 is in a shut-off state, the processing circuit 81 activates a supply source to adjust the braking pressure of the two braking pressures Pw(1) and Pw(2) that is not the one that has been determined to be abnormal, in the second abnormal braking control. At this time, the processing circuit 81 generates frictional braking force on the rear wheel located diagonally opposite the front wheel where frictional braking force is generated by the activation of the supply source that is the controlled object of the second abnormal braking control.

[0086] In the second abnormal braking control, when the braking system 40 generates friction braking force on the left front wheel 11, it generates friction braking force on the right rear wheel 14. Also, when the braking system 40 generates friction braking force on the right front wheel 12 in the second abnormal braking control, it generates friction braking force on the left rear wheel 13. This allows the braking system 40 to reduce the difference in braking force between the left and right wheels. Therefore, even if brake fluid leakage occurs in the left front wheel system or the right front wheel system, the braking system 40 can reduce the amount of deviation caused by vehicle braking of the moving vehicle 10.

[0087] (Second Embodiment) A second embodiment of the braking device will be described with reference to Figure 4. Note that the second embodiment differs from the first embodiment in some of the processing procedures after the switching unit is in the shut-off state. In the following description, the parts that differ from the first embodiment will be mainly described, and the same reference numerals will be used for components identical to those in the first embodiment to avoid redundant explanations.

[0088] Referring to Figure 4, a series of processes executed by the processing circuit 81 when an abnormality occurs in the braking units 411 and 412 will be explained. In step S21 shown in Figure 4, if the processing circuit 81 determines that the Mth supply source is operational (S21: NO), the processing circuit 81 proceeds to step S23. In step S23, the processing circuit 81 functions as the second abnormality control unit M22 and shuts off the switching unit 60.

[0089] In the following step S241, the processing circuit 81 determines whether the current braking request is an emergency braking request. If the deceleration requested for the vehicle 10 is greater than or equal to a threshold, it is considered an emergency braking request. If the processing circuit 81 determines that the current braking request is an emergency braking request (S241: YES), the processing circuit 81 proceeds to step S243. On the other hand, if the processing circuit 81 determines that the current braking request is not an emergency braking request (S241: NO), the processing circuit 81 proceeds to step S25.

[0090] In step S243, the processing circuit 81 performs emergency braking control by functioning as the second abnormality control unit M22. In emergency braking control, the processing circuit 81 increases the two braking pressures Pw(1) and Pw(2) by activating both of the two supply sources 421 and 422. In other words, if it is an emergency braking situation even if there is a possibility of brake fluid leakage in the left front wheel system or the right front wheel system, the processing circuit 81 generates frictional braking force on both of the two front wheels 11 and 12. The processing circuit 81 also generates frictional braking force on the two rear wheels 13 and 14 by activating the braking actuator 70. After that, when there is no further braking request, the processing circuit 81 terminates the emergency braking control and ends the series of processes shown in Figure 4.

[0091] <Operation and Effects of this Embodiment> (2-1) Emergency braking may be required when the switching unit 60 is in a shut-off state due to the possibility of brake fluid leakage in the left front wheel system or the right front wheel system. In this case, the braking device 40 increases the braking pressures Pw(1) and Pw(2) of the wheel cylinders 211 and 212 of the two front wheels 11 and 12 by operating both of the two supply sources 421 and 422.

[0092] If there is only a slight leak of brake fluid from either the left front wheel system or the right front wheel system, the braking system 40 can generate frictional braking force on the two front wheels 11 and 12 by performing the emergency braking control described above. This makes it easier for the braking system 40 to ensure braking force for the vehicle 10 compared to when frictional braking force is not generated on either the left front wheel 11 or the right front wheel 12.

[0093] (Examples of modifications) The above multiple embodiments can be implemented with the following modifications. The above multiple embodiments and the following examples of modifications can be combined with each other to the extent that they do not contradict each other technically.

[0094] - When increasing the friction braking force generated at the two rear wheels 13 and 14 during the implementation of the second abnormal braking control, the processing circuit 81 (i.e., the second abnormal control unit M22) may adjust the braking force at each wheel as shown below. For example, when generating friction braking force at the left front wheel 11 by the second abnormal braking control, it is preferable for the processing circuit 81 to adjust the friction braking forces of the left front wheel 11, left rear wheel 13, and right rear wheel 14 so that the difference between the rate of increase of the sum of the friction braking force of the left front wheel 11 and the friction braking force of the left rear wheel 13 and the rate of increase of the friction braking force of the right rear wheel 14 falls within the judgment value. This allows the processing circuit 81 to reduce the amount of vehicle 10 deflection associated with the implementation of the second abnormal braking control.

[0095] - The processing circuit 81 (i.e., the second abnormality control unit M22) does not have to perform part of the second abnormality braking control. That is, if the processing circuit 81 generates friction braking force on only one of the two front wheels 11 and 12 by the second abnormality braking control, it does not have to generate friction braking force on the two rear wheels 13 and 14. For example, if the processing circuit 81 performs the second abnormality braking control while the vehicle 10 is stopped, it does not have to generate braking force on the rear wheels 13 and 14 using the braking actuator 70. However, if the processing circuit 81 performs the second abnormality braking control while the vehicle 10 is moving, it may generate braking force on the rear wheels 13 and 14 using the braking actuator 70.

[0096] - The processing circuit 81 may have already obtained the following determination result before a braking request is issued. If a braking request is issued under these circumstances, the processing circuit 81 may set the switching unit 60 to a connected state and then execute the first abnormal braking control. In this case, the processing circuit 81 will activate the M supply source without activating the Nth supply source to adjust the braking pressures Pw(1) and Pw(2) of the two wheel cylinders 211 and 212.

[0097] (B11) An abnormality has occurred regarding the Nth braking pressure. (B12) The Nth supply source is inoperable, while the Mth supply source is operable. The processing circuit 81 may have already determined the following results before a braking request is made. If a braking request is made under these circumstances, the processing circuit 81 may shut down the switching unit 60 and then execute the second abnormal braking control. In this case, the processing circuit 81 will operate the Mth supply source without operating the Nth supply source to adjust the Mth braking pressure.

[0098] (B21) An abnormality has occurred with respect to the Nth braking pressure, while the Mth braking pressure is normal. (B22) Both the Nth and Mth supply sources are operational.

[0099] The braking system may also be configured to include a first supply source for adjusting the braking pressure Pw(1) of the wheel cylinder 211 for the left front wheel 11, and a second supply source for adjusting the braking pressure Pw(3) of the wheel cylinder 213 for the left rear wheel 13. In this case, the wheel cylinder 211 corresponds to the "first wheel cylinder," and the wheel cylinder 213 corresponds to the "second wheel cylinder." Also, the braking pressure Pw(1) corresponds to the "first braking pressure," and the braking pressure Pw(3) corresponds to the "second braking pressure."

[0100] The braking system may also be configured to include a first supply source for adjusting the braking pressure Pw(2) of the wheel cylinder 212 for the right front wheel 12, and a second supply source for adjusting the braking pressure Pw(4) of the wheel cylinder 214 for the right rear wheel 14. In this case, the wheel cylinder 212 corresponds to the "first wheel cylinder," and the wheel cylinder 214 corresponds to the "second wheel cylinder." Also, the braking pressure Pw(2) corresponds to the "first braking pressure," and the braking pressure Pw(4) corresponds to the "second braking pressure."

[0101] The braking system may also be configured to include a first supply source for adjusting the braking pressure Pw(3) of the wheel cylinder 213 for the left rear wheel 13, and a second supply source for adjusting the braking pressure Pw(4) of the wheel cylinder 214 for the right rear wheel 14. In this case, the wheel cylinder 213 corresponds to the "first wheel cylinder," and the wheel cylinder 214 corresponds to the "second wheel cylinder." Also, the braking pressure Pw(3) corresponds to the "first braking pressure," and the braking pressure Pw(4) corresponds to the "second braking pressure."

[0102] - The supply sources 421 and 422 may not include the electric cylinder 50 shown in Figure 1, as long as they are configured to supply brake fluid to the fluid passages 431 and 432 by driving an electric motor. For example, the supply sources 421 and 422 may include a pump powered by an electric motor.

[0103] The control device 80 may be configured to include multiple processing circuits. For example, the multiple processing circuits may include a processing circuit for controlling the braking unit 411, a processing circuit for controlling the braking unit 412, and a processing circuit for controlling the braking actuator 70.

[0104] For example, the multiple processing circuits may include a processing circuit that functions as an abnormality determination unit M11, a processing circuit that functions as an operation feasibility determination unit M13, a processing circuit that functions as a first abnormality control unit M21, and a processing circuit that functions as a second abnormality control unit M22.

[0105] The control device 80 may be configured as a circuit including one or more dedicated hardware circuits, such as one or more processors that operate according to a computer program, and dedicated hardware that performs at least some of the various processes, or a combination thereof. Examples of dedicated hardware include application-specific integrated circuits (ASICs). The processor includes a CPU and memory such as RAM and ROM, and the memory stores program code or instructions configured to cause the CPU to execute processes. The memory, i.e., storage medium, includes any available medium that can be accessed by a general-purpose or dedicated computer.

[0106] <Other Technical Concepts> The following describes the technical concepts that can be understood from the above-mentioned multiple embodiments and modifications. [Note 1] When a braking request occurs while the switching unit is in the communication state as determined by the first abnormality control unit, it is preferable that the first abnormality control unit adjusts the first braking pressure and the second braking pressure by activating the supply source among the first supply source and the second supply source that has been determined not to be inoperable by the operation feasibility determination unit.

[0107] [Note 2] Each of the first and second supply sources includes an electric motor, a rotation angle sensor for detecting the rotation angle of the electric motor, and a pressure sensor for detecting the supply pressure of the brake fluid of the supply source, and generates the supply pressure in accordance with the drive of the electric motor. Preferably, the inoperability determination unit determines that the supply source is inoperable when an abnormality occurs in at least one of the electric motor, the rotation angle sensor, and the pressure sensor.

[0108] In this specification, the expression "at least one" means "one or more" of the desired options. For example, if there are two options, the expression "at least one" means "only one option" or "both of the two options." As another example, if there are three or more options, the expression "at least one" means "only one option" or "a combination of two or more arbitrary options."

Claims

1. A braking device applicable to a vehicle having a first wheel cylinder and a second wheel cylinder, comprising: a first supply source connected to the first wheel cylinder via a first fluid passage and adjusting the first braking pressure, which is the hydraulic pressure of the first wheel cylinder, by supplying brake fluid to the first fluid passage; a second supply source connected to the second wheel cylinder via a second fluid passage and adjusting the second braking pressure, which is the hydraulic pressure of the second wheel cylinder, by supplying brake fluid to the second fluid passage; a switching unit that can switch between a communication state in which the first fluid passage and the second fluid passage are in communication and a disconnection state in which the communication between the first fluid passage and the second fluid passage is blocked, wherein the braking device controls the braking force of the vehicle by operating the first supply source, the second supply source and the switching unit, comprising: an abnormality determination unit that determines whether or not an abnormality has occurred with respect to at least one of the first braking pressure and the second braking pressure; and an operation feasibility determination unit that determines whether or not the first supply source and the second supply source are operable. A braking device comprising: a first abnormality control unit that puts the switching unit into the communication state when the abnormality determination unit determines that an abnormality has occurred and the operation feasibility determination unit determines that either the first supply source or the second supply source is inoperable; and a second abnormality control unit that puts the switching unit into the shut-off state when the abnormality determination unit determines that an abnormality has occurred and the operation feasibility determination unit determines that both the first supply source and the second supply source are operable.

2. The vehicle has a left front wheel, a right front wheel, a left rear wheel, and a right rear wheel, and the first wheel on which the first wheel cylinder is provided is one of the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel, and the second wheel on which the second wheel cylinder is provided is the wheel located diagonally opposite the first wheel and a wheel other than the first wheel, from among the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel, and the braking device comprises a braking actuator that generates braking force in two wheels other than the first wheel and the second wheel, from among the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel, and the abnormality determination unit determines whether or not an abnormality has occurred in the first braking pressure or the second braking pressure when the switching unit is in the shut-off state by the second abnormality control unit, The braking device according to claim 1, wherein the second abnormality control unit, when a braking request occurs while the switching unit is in the shut-off state as determined by the second abnormality control unit, stops the operation of the supply source that adjusts the braking pressure which the abnormality determination unit has determined to be abnormal, among the first and second supply sources, activates the supply source that adjusts the braking pressure which is not the braking pressure which the abnormality determination unit has determined to be abnormal, and activates the braking actuator to generate braking force on the wheel located diagonally opposite the wheel on which braking force is generated by the operation of the supply source, among the two wheels other than the first and second wheels.

3. The braking device according to claim 1, wherein the second abnormality control unit increases the first braking pressure and the second braking pressure by activating both the first supply source and the second supply source when emergency braking is required while the switching unit is in the shut-off state as determined by the second abnormality control unit.

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