Braking system

Abstract

To ensure that braking force can be generated in the vehicle even if one of the two power sources fails to supply power. [Solution] The braking system 30 includes two front wheel braking units 41FL, 41FR provided corresponding to each of the two wheel cylinders 21 and adjusting the hydraulic pressure of the corresponding wheel cylinders 21; a switching unit 43 that can switch between a connected state in which the two wheel cylinders 21 are in communication and a disconnected state in which the communication between the two wheel cylinders 21 is blocked; two rear wheel braking units 60RL, 60RR provided corresponding to each of the two rear wheels 11RL, 11RR and adjusting the braking force generated by the corresponding rear wheels 11RL, 11RR; a first power supply 71 that supplies power to the front wheel braking unit 41FL and the rear wheel braking unit 60RR; and a second power supply 72 that supplies power to the front wheel braking unit 41FR and the rear wheel braking unit 60RL.

Description

Technical Field

[0001] The present invention relates to a braking system provided in a vehicle.

Background Art

[0002] Patent Document 1 discloses a braking system including a plurality of braking units corresponding to each of a plurality of wheels. The plurality of braking units include electric motors driven by power supplied from a battery. The plurality of braking units generate braking force corresponding to the driving of the electric motors at the corresponding wheels.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the braking system as described above, redundancy is required.

Means for Solving the Problems

[0005] A braking system to solve the above problems is provided on a vehicle equipped with two first wheels and two second wheels, wherein the two first wheels are configured to generate a braking force corresponding to the hydraulic pressure of the corresponding wheel cylinders. The braking system comprises a hydraulic braking device having two braking units provided corresponding to each of the two wheel cylinders and electrically adjusting the hydraulic pressure of the corresponding wheel cylinders, and a switching unit that can switch between a connected state in which the two wheel cylinders are in communication and a disconnected state in which the two wheel cylinders are not in communication, two braking units provided corresponding to each of the two second wheels and electrically adjusting the braking force generated by the corresponding second wheel, a first power supply that supplies power to two first braking units which are specific braking units among the four braking units, and a second power supply that supplies power to two second braking units which are braking units other than the first braking units among the four braking units. [Effects of the Invention]

[0006] The braking system described above has the effect of being able to generate braking force in the vehicle even if one of the two power sources fails to supply power. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram showing a vehicle equipped with the braking system of the first embodiment. [Figure 2] Figure 2 is a schematic diagram showing the front wheel braking section of the braking system shown in Figure 1. [Figure 3] Figure 3 is a flowchart showing the series of processes for selecting a braking mode in the braking system shown in Figure 1. [Figure 4] Figure 4 is a diagram illustrating the operation of the braking system shown in Figure 1 when an abnormality occurs in the second power supply. [Figure 5] Figure 5 is a schematic diagram showing a vehicle equipped with the braking system of the second embodiment. [Figure 6] Figure 6 is a schematic diagram showing a vehicle equipped with the braking system of the third embodiment. [Figure 7] Figure 7 is a schematic diagram showing a vehicle equipped with the braking system of the fourth embodiment. [Modes for carrying out the invention]

[0008] (First Embodiment) A first embodiment of the braking system will be described with reference to Figures 1 to 4. <Overall vehicle configuration> Figure 1 illustrates a vehicle 10 equipped with a braking system 30. The vehicle 10 has a left front wheel 11FL, a right front wheel 11FR, a left rear wheel 11RL, and a right rear wheel 11RR. In this embodiment, the two front wheels 11FL and 11FR correspond to the "first wheels," and the two rear wheels 11RL and 11RR correspond to the "second wheels."

[0009] Vehicle 10 is equipped with two friction brakes 20FL and 20FR for the front wheels. Friction brake 20FL corresponds to the left front wheel 11FL. Friction brake 20FR corresponds to the right front wheel 11FR. Each of the multiple friction brakes 20FL and 20FR is configured to generate braking force at the corresponding front wheel 11FL and 11FR by pressing friction material against a rotating body that rotates integrally with the corresponding front wheel 11FL and 11FR. Each of the multiple friction brakes 20FL and 20FR has a wheel cylinder 21. The higher the braking pressure, which is the hydraulic pressure of the wheel cylinder 21, the greater the braking force generated at the front wheels 11FL and 11FR.

[0010] <Configuration of the braking system> The braking system 30 includes a hydraulic braking device 40, two rear wheel braking units 60RL and 60RR, a first power supply 71, a second power supply 72, and a control device 80.

[0011] The hydraulic braking system 40 is equipped with two front wheel braking units 41FL and 41FR. Front wheel braking unit 41FL is a braking unit that electrically adjusts the braking pressure of the wheel cylinder 21 of the friction brake 20FL corresponding to the left front wheel 11FL. Front wheel braking unit 41FR is a braking unit that electrically adjusts the braking pressure of the wheel cylinder 21 of the friction brake 20FR corresponding to the right front wheel 11FR. Front wheel braking units 41FL and 41FR are in communication with the wheel cylinder 21 via a supply passage, which is a flow path for brake fluid. Hereafter, the supply passage connecting the front wheel braking unit 41FL and the wheel cylinder 21 of the friction brake 20FL will be referred to as "supply passage 42FL", and the supply passage connecting the front wheel braking unit 41FR and the wheel cylinder 21 of the friction brake 20FR will be referred to as "supply passage 42FR".

[0012] Figure 2 illustrates an example of a front wheel braking unit 41FL, 41FR. Multiple front wheel braking units 41FL, 41FR have an electric cylinder 50 as a source of brake fluid to the wheel cylinder 21. The electric cylinder 50 includes a cylinder 51, a piston 52, an electric motor 53, and a conversion mechanism 54. The piston 52 is provided in a slidable state 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.

[0013] 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.

[0014] Cylinder 51 has an output port 51P that connects the hydraulic chamber Re to the outside. The output port 51P is always open. Supply lines 42FL and 42FR are connected to the output port 51P.

[0015] When the electric motor 53 is driven and the motor rotation angle, which is the rotation angle of the rotation shaft of the electric motor 53, increases, the piston 52 moves in the forward direction Za. As a result, the brake fluid in the hydraulic chamber Re is discharged into the supply paths 42FL and 42FR via the output port 51P. Thereby, since the brake fluid is supplied to the wheel cylinder 21, the braking pressure increases. On the other hand, when the electric motor 53 is driven and the motor rotation angle decreases, the piston 52 moves in the backward direction Zb. As a result, the brake fluid in the supply paths 42FL and 42FR flows into the hydraulic chamber Re via the output port 51P. Thereby, since the brake fluid flows out from the wheel cylinder 21, the braking pressure decreases.

[0016] As shown in FIG. 1, the hydraulic braking device 40 includes a switching unit 43 that can be switched between a communicating state in which two wheel cylinders 21 communicate with each other and a blocking state in which the communication between the two wheel cylinders 21 is blocked. For example, the switching unit 43 includes a communication path 44 and a shut-off valve 45 installed in the communication path 44. The communication path 44 is a flow path of brake fluid that connects the supply path 42FL and the supply path 42FR. An example of the shut-off valve 45 is a normally open solenoid valve. When power is not supplied to the solenoid of the shut-off valve 45, the shut-off valve 45 opens, so that the two supply paths 42FL and 42FR communicate with each other via the communication path 44. On the other hand, when power is supplied to the solenoid of the shut-off valve 45, the shut-off valve 45 closes, so that the communication between the two supply paths 42FL and 42FR via the communication path 44 is blocked. Therefore, the state of the switching unit 43 in which the shut-off valve 45 is open is the communicating state. On the other hand, the state of the switching unit 43 in which the shut-off valve 45 is closed is the blocking state.

[0017] The rear wheel braking unit 60RL is provided corresponding to the left rear wheel 11RL and is a braking unit that electrically adjusts the braking force generated by the left rear wheel 11RL. The rear wheel braking unit 60RR is provided corresponding to the right rear wheel 11RR and is a braking unit that electrically adjusts the braking force generated by the right rear wheel 11RR. The rear wheel braking units 60RL and 60RR are electric braking devices that use an electric motor 61 as a power source. When the rotation angle of the output shaft of the electric motor 61 in the rear wheel braking units 60RL and 60RR increases, the braking force generated by the corresponding rear wheels 11RL and 11RR increases. On the other hand, when the rotation angle of the output shaft decreases, the braking force generated by the corresponding rear wheels 11RL and 11RR decreases. Examples of the rear wheel braking units 60RL and 60RR include the electric braking device disclosed in "Japanese Patent Application Laid-Open No. 2024-108148".

[0018] The first power source 71 and the second power source 72 are power sources for the hydraulic braking device 40 and the rear wheel braking units 60RL and 60RR. The first power source 71 supplies power to two first braking units, which are specific braking units, among the two front wheel braking units 41FL and 41FR and the two rear wheel braking units 60RL and 60RR. The second power source 72 supplies power to two second braking units, which are the two braking units other than the two first braking units, among the two front wheel braking units 41FL and 41FR and the two rear wheel braking units 60RL and 60RR.

[0019] In the braking system 30, the first power source 71 supplies power to the front wheel braking unit 41FL and the rear wheel braking unit 60RR. On the other hand, the first power source 71 does not supply power to the front wheel braking unit 41FR and the rear wheel braking unit 60RL. The second power source 72 supplies power to the front wheel braking unit 41FR and the rear wheel braking unit 60RL. On the other hand, the second power source 72 does not supply power to the front wheel braking unit 41FL and the rear wheel braking unit 6RR. That is, the front wheel braking unit 41FL and the rear wheel braking unit 60RR correspond to the "first braking unit". The front wheel braking unit 41FR and the rear wheel braking unit 60RL correspond to the "second braking unit".

[0020] Both the first power supply 71 and the second power supply 72 are capable of supplying power to the switching unit 43. Therefore, even if one of the power supplies, the first power supply 71 or the second power supply 72, becomes unable to supply power, the switching unit 43 can still be driven by power supplied from the other power supply.

[0021] The control device 80 receives detection signals from multiple sensors. These multiple sensors include a brake sensor 101 that detects the amount of operation of the driver's braking mechanism 15 of the vehicle 10. Based on these detection signals from multiple sensors, the control device 80 controls the two front wheel braking units 41FL, 41FR and the two rear wheel braking units 60RL, 60RR and the switching unit 43 of the braking system 30.

[0022] The control device 80 includes a processing circuit. An example of a processing circuit is an electronic control device. In this case, the processing circuit includes a CPU and a memory that stores a control program executed by the CPU. The CPU executes the control program in the memory, thereby allowing the processing circuit of the control device 80 to control the braking system 30.

[0023] The control device 80 provides two braking modes for controlling the braking force Fx of the vehicle 10: a normal braking mode and a three-wheel braking mode. The normal braking mode is a braking mode in which the switching unit 43 is shut off and the two front wheel braking units 41FL, 41FR and the two rear wheel braking units 60RL, 60RR are activated. When controlling the braking force Fx of the vehicle 10 in the normal braking mode, the control device 80 can generate braking force at all four wheels 11FL, 11FR, 11RL, and 11RR.

[0024] The three-wheel braking mode is a braking mode in which the switching unit 43 is set to a connected state, and one of the two front wheel braking units 41FL, 41FR and one of the two rear wheel braking units 60RL, 60RR are activated. When controlling the braking force Fx of the vehicle 10 in three-wheel braking mode, the control device 80 can generate braking force on all three wheels.

[0025] <Braking mode selection process> Referring to Figure 3, a series of processes performed by the control device 80 when selecting a braking mode will be explained. This series of processes is the braking mode selection process.

[0026] In step S11, the control device 80 determines whether only one of the first power supply 71 and the second power supply 72 is abnormal. Here, "abnormal power supply" includes a state in which power cannot be supplied to the target of power supply, and a state in which there is a possibility that power cannot be supplied to the target of power supply. For example, the control device 80 determines that an abnormal power supply has occurred if at least one of the following multiple conditions is met. In this case, the control device 80 determines that no abnormal power supply has occurred if none of the multiple conditions are met.

[0027] • The power supply voltage must be below the specified voltage. - Even when the braking unit is activated, no braking force is generated in the wheel corresponding to that braking unit. • The power supply line connecting the power source to the object it is supplying power to is broken.

[0028] The specified voltage is the minimum voltage or slightly higher power required to operate the braking system properly. In step S11, if the control device 80 determines that only one of the first power supply 71 and the second power supply 72 is abnormal (S11: YES), the control device 80 proceeds to step S13. On the other hand, if the control device 80 determines that neither the first power supply 71 nor the second power supply 72 is abnormal (S11: NO), the control device 80 proceeds to step S15. In other words, if both the first power supply 71 and the second power supply 72 are normal, the control device 80 proceeds to step S15.

[0029] In step S13, the control device 80 selects the three-wheel braking mode as the braking mode. Then, the control device 80 terminates the braking mode selection process. In step S15, the control device 80 selects the normal braking mode as the braking mode. Then, the control device 80 terminates the braking mode selection process.

[0030] <Effects when 3-wheel braking mode is selected> Referring to Figure 4, let us explain, for example, the case where only the second power supply 72 of the two power supplies 72 (the first power supply 71 and the second power supply 72) malfunctions. In this case, as shown by arrow Y1 in Figure 4, the first power supply 71 can supply power to the front wheel braking unit 41FL for the left front wheel 11FL, the rear wheel braking unit 60RR for the right rear wheel 11RR, and the switching unit 43. Therefore, the control device 80 connects the switching unit 43. Then, the control device 80 activates the front wheel braking unit 41FL. In this case, since the two wheel cylinders 21 are connected via the communication passage 44, as shown by arrow Y2 in Figure 4, the brake fluid supplied from the front wheel braking unit 41FL is supplied to the two wheel cylinders 21. As a result, the activation of the front wheel braking unit 41FL generates braking force in both of the two front wheels 11FL and 11FR.

[0031] Furthermore, the control device 80 can generate braking force at the right rear wheel 11RR by activating the rear wheel braking unit 60RR. Therefore, the control device 80 can generate braking force on the three wheels, namely the left front wheel 11FL, the right front wheel 11FR, and the right rear wheel 11RR.

[0032] Furthermore, even if an abnormality occurs only in the first power supply 71 of the two power supplies 72, the control device 80 can still generate braking force on all three wheels. The processing flow in this case is substantially the same as when an abnormality occurs only in the second power supply 72, so a detailed explanation will be omitted. In this case, the control device 80 can generate braking force on the left front wheel 11FL, the right front wheel 11FR, and the left rear wheel 11RL.

[0033] <Effects of this embodiment> (1-1) In the braking system 30, if an abnormality occurs in only one of the first power supply 71 and the second power supply 72, power can be supplied from the other power supply to two of the four braking units. Therefore, the braking system 30 can generate a braking force Fx in the vehicle 10 even if one of the two power supplies 71 and 72 is unable to supply power.

[0034] (1-2) Even if an abnormality occurs in only one of the first power supply 71 and the second power supply 72, if one of the two front wheel braking units 41FL, 41FR is operational, the braking system 30 can generate braking force in both front wheels 11FL, 11FR by operating the one front wheel braking unit after connecting the switching unit 43.

[0035] (1-3) The two front wheel braking units 41FL, 41FR each include one of the two first braking units and one of the two second braking units. Furthermore, the two rear wheel braking units 60RL, 60RR each include the remaining one of the two first braking units and the remaining one of the two second braking units. Therefore, even if a malfunction occurs in only one of the first power supply units 71 and the second power supply unit 72, the hydraulic braking system 40 can generate braking force on the two front wheels 11FL, 11FR, and one of the two rear wheel braking units 60RL, 60RR can operate. Thus, the braking system 30 can generate braking force on all three wheels even if only one of the first power supply units 71 and the second power supply unit 72 malfunctions.

[0036] (1-4) The two wheels that are subject to the generation of braking force by the hydraulic braking device 40 include the right front wheel 11FR and the left front wheel 11FL. Therefore, even if an abnormality occurs in only one of the first power supply 71 and the second power supply 72, the braking system 30 can generate braking force on one of the two right wheels 11FR, 11RR and one of the two left wheels 11FL, 11RL by setting the state of the switching unit 43 to a communication state.

[0037] Furthermore, the first power supply 71 and the second power supply 72 can supply power to one of the braking units provided on the right wheels 11FR and 11RR, and to one of the braking units provided on the left wheels 11FL and 11RL. Therefore, even if only one of the first power supply 71 or the second power supply 72 malfunctions, braking force can still be generated on one of the two right wheels and one of the two left wheels. As a result, the braking system 30 can suppress the deviation of the vehicle 10 when the vehicle is being braked.

[0038] (1-5) The first power supply 71 can supply power to two of the four braking units, but not to the remaining two. Similarly, the second power supply 72 can supply power to two of the four braking units, but not to the remaining two. Therefore, compared to a configuration where each of the two power supplies 71 and 72 can supply power to any of the four braking units, the braking system 30 can reduce the number of power supply lines.

[0039] (Second Embodiment) A second embodiment of the braking system will be described with reference to Figure 5. In the following description, the differences from the first embodiment will be mainly described, and the same reference numerals will be used for components that are the same as or equivalent to those in the first embodiment, and redundant explanations will be omitted.

[0040] As shown in Figure 5, in the braking system 30A of this embodiment, the first power supply 71 supplies power to the hydraulic braking device 40, i.e., the two front wheel braking units 41FL, 41FR and the switching unit 43. On the other hand, the first power supply 71 cannot supply power to the two rear wheel braking units 60RL, 60RR. The second power supply 72 supplies power to the two rear wheel braking units 60RL, 60RR. On the other hand, the second power supply 72 cannot supply power to the hydraulic braking device 40.

[0041] <If a malfunction occurs in only the first power supply out of the two power supplies> In this case, although the two front wheel braking units 41FL, 41FR and the switching unit 43 cannot operate, the two rear wheel braking units 60RL, 60RR can operate. Therefore, when a braking request occurs under these circumstances, the control device 80 activates the two rear wheel braking units 60RL, 60RR to generate braking force on the two rear wheels 11RL, 11RR.

[0042] <If a malfunction occurs in only the second power supply out of the two power supplies> In this case, although the two rear wheel braking units 60RL and 60RR cannot be operated, the two front wheel braking units 41FL and 41FR and the switching unit 43 can be operated. Therefore, when a braking request occurs under these circumstances, the control device 80 operates the two front wheel braking units 41FL and 41FR to generate braking force on the two front wheels 11FL and 11FR.

[0043] Furthermore, an abnormality may occur in only one of the two front wheel braking units 41FL and 41FR. In this case, the control device 80 connects the switching unit 43 and activates the other front wheel braking unit 41FL and 41FR that is not malfunctioning. As a result, the control device 80 can generate braking force on both front wheels 11FL and 11FR by activating only one of the two front wheel braking units 41FL and 41FR.

[0044] In the braking system 30A of this embodiment, effects equivalent to those of the first embodiment described above (1-1), (1-4), and (1-5) can be obtained. (Third embodiment) A third embodiment of the braking system will be described with reference to Figure 6. In the following description, the differences from the above-described embodiments will be mainly explained, and the same reference numerals will be used for components that are the same as or equivalent to those in the above-described embodiments, and redundant explanations will be omitted.

[0045] As shown in Figure 6, in the braking system 30B of this embodiment, the first power supply 71 supplies power to the front wheel braking unit 41FL for the left front wheel 11FL, the rear wheel braking unit 60RL for the left rear wheel 11RL, and the switching unit 43. On the other hand, the first power supply 71 cannot supply power to the front wheel braking unit 41FR for the right front wheel 11FR and the rear wheel braking unit 60RR for the right rear wheel 11RR. The second power supply 72 supplies power to the front wheel braking unit 41FR, the rear wheel braking unit 60RR, and the switching unit 43. On the other hand, the second power supply 72 cannot supply power to the front wheel braking unit 41FL and the rear wheel braking unit 60RL.

[0046] <If a malfunction occurs in only the first power supply out of the two power supplies> In this case, although the front wheel braking unit 41FL and the rear wheel braking unit 60RL cannot be operated, the front wheel braking unit 41FR, the rear wheel braking unit 60RR, and the switching unit 43 can be operated. Therefore, when a braking request occurs under these circumstances, the control device 80 activates the front wheel braking unit 41FR after connecting the switching unit 43. The control device 80 also activates the rear wheel braking unit 60RR. As a result, the control device 80 can generate braking force on three wheels, namely the two front wheels 11FL and 11FR and the right rear wheel 11RR.

[0047] Furthermore, the action taken when only the second power supply 72 malfunctions compared to the first power supply 71 is the same as when only the first power supply 71 malfunctions. Therefore, a detailed explanation of this case will be omitted.

[0048] The braking system 30B of this embodiment can obtain effects equivalent to those of the first embodiment described above (1-1) to (1-5). (Fourth Embodiment) A fourth embodiment of the braking system will be described with reference to Figure 7. In the following description, the differences from the above-described embodiments will be mainly explained, and the same reference numerals will be used for components that are the same as or equivalent to those in the above-described embodiments, and redundant explanations will be omitted.

[0049] Figure 7 shows a vehicle 10 equipped with the braking system 30C of this embodiment. The vehicle 10 is equipped with two friction brakes 20RL and 20RR for the rear wheels. Friction brake 20RL corresponds to the left rear wheel 11RL. Friction brake 20RR corresponds to the right rear wheel 11RR. The configuration of friction brakes 20RL and 20RR is substantially the same as that of friction brakes 20FL and 20FR for the front wheels 11FL and 11FR. In other words, the two friction brakes 20RL and 20RR can generate braking force at the corresponding rear wheels 11RL and 11RR in accordance with the braking pressure of the wheel cylinder 21.

[0050] <Configuration of the braking system> The braking system 30C is equipped with a first hydraulic brake 40L and a second hydraulic brake 40R as hydraulic brake devices. The first hydraulic brake 40L generates braking force on the left wheels 11FL and 11RL by adjusting the braking pressure of the wheel cylinder 21 corresponding to the left wheels 11FL and 11RL. The second hydraulic brake 40R generates braking force on the right wheels 11FR and 11RR by adjusting the braking pressure of the wheel cylinder 21 corresponding to the right wheels 11FR and 11RR. In other words, if the left wheels 11FL and 11RL are considered the "first wheels," then the right wheels 11FR and 11RR correspond to the "second wheels." Conversely, if the right wheels 11FR and 11RR are considered the "first wheels," then the left wheels 11FL and 11RL correspond to the "second wheels."

[0051] The first hydraulic braking system 40L comprises a front wheel braking section 41FL, a rear wheel braking section 160RL, and a first switching section 43L. The second hydraulic braking system 40R comprises a front wheel braking section 41FR, a rear wheel braking section 160RR, and a second switching section 43R. The rear wheel braking sections 160RL and 160RR have, for example, the same electric cylinder 50 shown in Figure 2 as the front wheel braking sections 41FL and 41FR.

[0052] The rear wheel braking unit 160RL communicates with the wheel cylinder 21 of the friction brake 20RL for the left rear wheel 11RL via the supply passage 42RL. The rear wheel braking unit 160RR communicates with the wheel cylinder 21 of the friction brake 20RR for the right rear wheel 11RR via the supply passage 42RR.

[0053] The first switching unit 43L is configured to switch between a communication state, which connects the wheel cylinder 21 for the left front wheel 11FL and the wheel cylinder 21 for the left rear wheel 11RL, and a disconnection state, which disconnects the two wheel cylinders 21. The first switching unit 43L includes a first communication passage 44L that connects the supply passage 42FL and the supply passage 42RL, and a shut-off valve 45L installed in the first communication passage 44L. An example of the shut-off valve 45L is a normally open solenoid valve.

[0054] The second switching unit 43R is configured to switch between a communication state, which connects the wheel cylinder 21 for the right front wheel 11FR and the wheel cylinder 21 for the right rear wheel 11RR, and a disconnection state, which disconnects the two wheel cylinders 21. The second switching unit 43R includes a second communication passage 44R connecting the supply passage 42FR and the supply passage 42RR, and a shut-off valve 45R installed in the second communication passage 44R. An example of the shut-off valve 45R is a normally open solenoid valve.

[0055] The first power supply 71 supplies power to the two front wheel braking units 41FL and 41FR, and to the first switching unit 43L and the second switching unit 43R. The second power supply 72 supplies power to the two rear wheel braking units 160RL and 160RR, and to the first switching unit 43L and the second switching unit 43R. In other words, the two front wheel braking units 41FL and 41FR correspond to the "first braking unit," and the two rear wheel braking units 160RL and 160RR correspond to the "second braking unit."

[0056] <If a malfunction occurs in only the first power supply out of the two power supplies> In this case, although the two front wheel braking units 41FL and 41FR cannot be operated, the two rear wheel braking units 160RL and 160RR, and the first switching unit 43L and the second switching unit 43R can be operated. Therefore, the control device 80 connects the first switching unit 43L and the second switching unit 43R and then operates the two rear wheel braking units 160RL and 160RR. As a result, the control device 80 can generate braking force on all four wheels 11FL, 11FR, 11RL, and 11RR.

[0057] Furthermore, if a malfunction occurs only in the second power supply 72 of the two power supplies 72, the situation is the same as when a malfunction occurs only in the first power supply 71, except that the braking units supplied with power are the two front wheel braking units 41FL and 41FR.

[0058] (Example of change) The above embodiments can be implemented with the following modifications. The above embodiments and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0059] In the fourth embodiment described above, the two braking units for the right wheel 11FR, 11RR or the left wheel 11FL, 11RL may be electric braking devices that generate braking force without using brake fluid.

[0060] In the third embodiment described above, if the second power supply 72 can supply power to the shut-off valve 45, the first power supply 71 does not need to supply power to the switching unit 43. In this case, if an abnormality occurs in the second power supply 72, power will no longer be supplied to the shut-off valve 45, and the switching unit 43 will open. In other words, the switching unit 43 will be in a communication state. Therefore, braking force can be generated on the two front wheels 11FL and 11FR by the operation of the front wheel braking unit 41FL.

[0061] The switching units 43, 43L, and 43R may have configurations different from those described in the above embodiments, as long as they are capable of switching between a connected state and a disconnected state. In the first embodiment, the braking system may be configured to include a hydraulic braking device that can adjust the braking force of the two rear wheels 11RL and 11RR. In this case, the two rear wheels 11RL and 11RR correspond to the "first wheels," and the two front wheels 11FL and 11FR correspond to the "second wheels."

[0062] The brake fluid supply source to the wheel cylinder 21 may be anything other than the electric cylinder 50 shown in Figure 2, as long as the brake fluid can be supplied by driving an electric motor. For example, the supply source may be an electric pump or a configuration with an accumulator.

[0063] The control device 80 may be configured as a circuit including one or more processors that operate according to a computer program, one or more dedicated hardware circuits that perform 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 perform the processes. The memory, i.e., storage medium, includes any available medium that can be accessed by a general-purpose or dedicated computer.

[0064] (Other technological ideas) This section describes the technical concepts that can be understood from the above-mentioned multiple embodiments and modifications. [Note 1] The two first braking units each have an electric motor powered by the first power source, and generate a braking force in the corresponding wheel in accordance with the drive of the electric motor. Preferably, the two second braking units each have an electric motor powered by the second power source, and generate a braking force in the corresponding wheel in accordance with the drive of the electric motor.

[0065] [Note 2] Preferably, the switching unit is operated by power supplied from at least one of the first power supply and the second power supply.

[0066] [Note 3] The switching unit has a normally open type solenoid valve. When the solenoid valve is closed, the switching unit enters the shut-off state. When the solenoid valve is open, it is preferable that the switching section is in the communication state.

[0067] [Note 4] The system includes a control device that controls the four braking units, Preferably, the control device adjusts the braking force of the vehicle by setting the switching unit to the communication state when an abnormality occurs in only one of the first power supply or the second power supply, and activating the braking unit among the four braking units that operates using power supplied from a power supply that is not experiencing an abnormality.

[0068] 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." [Explanation of Symbols]

[0069] 10... Vehicles 11FL, 11FR, 11RL, 11RR…wheels 21... Wheel cylinder 30, 30A~30C... Braking system 40, 40L, 40R… Hydraulic braking system 41FL, 41FR…Front wheel brake section 43, 43L, 43R… Switching section 50…Electric Cylinder 53… Electric motor 60RL,60RR,160RL,160RR…Rear wheel braking part 61… Electric motor 71...1st power supply 72…Second power supply 80...Control device

Claims

1. A vehicle is provided with two first wheels and two second wheels, wherein the two first wheels are configured to generate braking force corresponding to the hydraulic pressure of the corresponding wheel cylinders. A hydraulic braking device having two braking units provided corresponding to each of the two wheel cylinders for electrically adjusting the hydraulic pressure of the corresponding wheel cylinder, and a switching unit that can switch between a connected state in which the two wheel cylinders are in communication and a disconnected state in which the two wheel cylinders are disconnected, Two braking units are provided corresponding to each of the two second wheels, and electrically adjust the braking force generated by the corresponding second wheel. A first power supply that supplies power to two first braking units, which are specific braking units among the four braking units, The system includes a second power supply that supplies power to two second braking units, which are the four braking units other than the first braking unit. Braking system.

2. The two braking units of the hydraulic braking device include one of the two first braking units and one of the two second braking units. The braking system according to claim 1.

3. The two first wheels include the right wheel of one of the right front wheel and the right rear wheel, and the left wheel of one of the left front wheel and the left rear wheel. When the switching unit is in the communication state, the hydraulic braking device generates braking force on the right wheel and the left wheel by activating one of the two braking units provided in the hydraulic braking device. The braking system according to claim 1 or claim 2.

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