Brake system

Abstract

To allow regenerative power generated by an electric motor of an electrically-driven brake to be consumed appropriately.SOLUTION: A brake system 20 is provided with a plurality of electrically-driven brakes 21 to 24. The plurality of electrically-driven brakes 21 to 24 have electric motors 71, 72. In the brake system 20, it is determined by the electric motors 71, 72 whether or not regenerative power is to be generated, and when it is determined that the regenerative power is to be generated in one of the plurality of electric motors 71, 72, one electric motor is driven so that power consumption of another electric motor other than the one electric motor which is determined to generate the regenerative power is increased.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a brake system applied to a vehicle. [Background technology]

[0002] Patent document 1 discloses a brake system in which, of the regenerative power generated by the main motor that applies regenerative braking force to the vehicle, surplus power that cannot be stored in the vehicle's power storage unit is consumed by an auxiliary motor that is different from the main motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-333549 Summary of the Invention [Problem to be solved by the invention]

[0004] Brake systems include systems that include electric braking devices mounted on wheels. In such systems, regenerative power may be generated by an electric motor included in the electric braking device. The electric motor included in the electric braking device corresponds to the auxiliary motor in the brake system of Patent Document 1. An object of the present invention is to enable appropriate consumption of regenerative power generated by the electric motor of the electric braking device. [Means for solving the problem]

[0005] An example of a brake system for solving the above problem is applied to a vehicle having a first wheel and a second wheel as wheels. The brake system includes a first electric braking device that applies a braking force to the first wheel and a second electric braking device that applies a braking force to the second wheel. The first electric braking device and the second electric braking device apply a braking force to the wheel by bringing a friction portion into contact with a friction target portion, and each include an actuator that transitions the operating state of the electric braking device between a contact state in which the friction portion is in contact with the friction target portion and a separation state in which the friction portion is separated from the friction target portion. A first electric motor that is a power source for the actuator of the first electric braking device and a second electric motor that is a power source for the actuator of the second electric braking device are connected to a common power supply circuit. This brake system also includes a determination unit that determines whether regenerative power is generated in the first electric motor, and a control unit that increases the amount of power consumed by the second electric motor when the determination unit determines that regenerative power is generated in the first electric motor.

[0006] Because the first electric motor and the second electric motor are connected to a common power supply circuit, regenerative power generated by the first electric motor can be supplied to the second electric motor via the power supply circuit. Therefore, in the above-described brake system, when it is determined that regenerative power is being generated by the first electric motor, the amount of power consumed by the second electric motor is increased. This allows at least a portion of the regenerative power generated by the first electric motor to be consumed by the second electric motor. Therefore, the above-described brake system can appropriately consume the regenerative power generated by the electric motor of the first electric braking device.

[0007] One example of a brake system for solving the above problem is applied to a vehicle with three or more wheels. This brake system includes three or more electric braking devices corresponding to the three or more wheels. The three or more electric braking devices apply braking force to the wheels by bringing friction parts into contact with frictioned parts, and each of the three or more electric braking devices has an actuator that transitions the operating state of the electric braking device between a contact state in which the friction part is in contact with the frictioned part and a separation state in which the friction part is separated from the frictioned part. Electric motors that serve as power sources for the three or more actuators are connected to a common power supply circuit. Such a brake system includes a determination unit that determines whether at least one of the three or more electric motors will generate regenerative power; a selection unit that selects, based on the operating state of the electric braking device having an electric motor other than the power generating motor, which is the electric motor determined by the determination unit to generate regenerative power, from the electric motors other than the power generating motor, an electric motor that will consume the regenerative power generated by the power generating motor; and a control unit that increases the power consumption of the power consuming motor selected by the selection unit when the determination unit determines that any of the three or more electric motors will generate regenerative power.

[0008] Because the three or more electric motors are connected to a common power supply circuit, regenerative power generated by any one of the three or more electric motors can be supplied via the power supply circuit to electric motors other than the electric motor that generated the regenerative power. Therefore, in the above-described brake system, if a power-generating motor is determined to generate regenerative power among the three or more electric motors, a power-consuming motor is selected from among the electric motors other than the power-generating motor based on the operating states of the other electric braking devices other than the electric braking device that includes the power-generating motor. The power-consuming motor is then driven to increase its power consumption. As a result, when regenerative power is generated by any one of the three or more electric motors, the regenerative power generated by the power-generating motor can be consumed by the other electric motors. Therefore, the above-described brake system can appropriately consume the regenerative power generated by the electric motors of the electric braking devices. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a vehicle equipped with a brake system according to a first embodiment. [Figure 2] FIG. 2 is a block diagram showing a control configuration of the brake system of the first embodiment. [Figure 3] FIG. 3 is a graph showing the rotation coordinates of vector control. [Figure 4] FIG. 4 is a flowchart showing the power consumption increase request process executed by the execution unit of the electric braking device in the brake system of the first embodiment. [Figure 5] FIG. 5 is a flowchart showing the power consumption increase process executed by the execution unit of the electric braking device in the brake system of the first embodiment. [Figure 6] FIG. 6 is a schematic diagram showing the configuration of a vehicle equipped with a brake system according to the second embodiment. [Figure 7] FIG. 7 is a block diagram showing a control configuration of the brake system of the second embodiment. [Figure 8]FIG. 8 is a flowchart showing the power consumption increase request process executed by the execution unit of the overall control device in the brake system of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) A first embodiment of a brake system will be described below with reference to FIGS. 1, a vehicle 10 includes a plurality of wheels and a brake system 20 that adjusts the braking force applied to the plurality of wheels. The vehicle 10 includes a left front wheel 11, a right front wheel 12, a left rear wheel 13, and a right rear wheel 14 as the wheels.

[0011] <Brake system> The brake system 20 includes a plurality of electric braking devices 21, 22, 23, 24 provided individually for a plurality of wheels 11 to 14, a plurality of power supply circuits 26, 27, and an overall control device 30. Of the plurality of electric braking devices, the electric braking devices 21, 22 that apply braking force to the front wheels 11, 12 are referred to as "front wheel electric braking devices 21, 22," and the electric braking devices 23, 24 that apply braking force to the rear wheels 13, 14 are referred to as "rear wheel electric braking devices 23, 24."

[0012] Of the multiple power supply circuits 26, 27, the first power supply circuit 26 supplies power to the front wheel electric braking device 21 that applies braking force to the left front wheel 11 and the rear wheel electric braking device 24 that applies braking force to the right rear wheel 14. The second power supply circuit 27 supplies power to the front wheel electric braking device 22 that applies braking force to the right front wheel 12 and the rear wheel electric braking device 23 that applies braking force to the left rear wheel 13.

[0013] The overall control device 30 has an execution unit 31 and a storage unit 32. For example, the execution unit 31 is a CPU. The storage unit 32 stores various control programs to be executed by the execution unit 31. The execution unit 31 executes the control programs to derive braking force command values, which are command values ​​for braking forces to be applied to the wheels 11-14 by the electric braking devices 21-24. The execution unit 31 then operates the electric braking devices 21-24 by transmitting the braking force command values ​​to control units 81, 82, 83, and 84 of the electric braking devices 21-24, which will be described later.

[0014] <Front wheel electric braking device> In this embodiment, the front wheel electric braking devices 21, 22 are wet-type electric braking devices. Specifically, the front wheel electric braking devices 21, 22 have a friction part 41, a frictioned part 42, a wheel cylinder 43, an electric cylinder 44, an electric motor 71, and a control unit. The control unit for the front wheel electric braking device 21 for the left front wheel 11 is referred to as "control unit 81," and the control unit for the front wheel electric braking device 22 for the right front wheel 12 is referred to as "control unit 82."

[0015] Because the frictional portion 42 rotates integrally with the front wheels 11, 12, a braking force is applied to the front wheels 11, 12 by bringing the frictional portion 41 into contact with the frictional portion 42. When no hydraulic pressure is generated in the wheel cylinder 43, the frictional portion 41 is spaced apart from the frictional portion 42. When hydraulic pressure is generated in the wheel cylinder 43, the frictional portion 41 comes into contact with the frictional portion 42, i.e., the frictional portion 41 is pressed against the frictional portion 42. The higher the hydraulic pressure in the wheel cylinder 43, the greater the force pressing the frictional portion 41 against the frictional portion 42, and therefore the greater the braking force applied to the front wheels 11, 12.

[0016] The electric cylinder 44 has a transmission mechanism 45, a cylinder 48, and a piston 49. The transmission mechanism 45 has a rotating part 46 that rotates in synchronization with the electric motor 71, and a linearly moving part 47 that moves linearly in a direction corresponding to the rotation of the rotating part 46. The piston 49 is disposed in the cylinder 48. When the linearly moving part 47 moves linearly in response to the rotation of the rotating part 46, the piston 49 moves linearly within the cylinder 48. A fluid chamber 50 is defined within the cylinder 48 by the piston 49, and the fluid chamber 50 is connected to the wheel cylinder 43 via a fluid passage 51. When the piston 49 moves linearly in a direction that reduces the volume of the fluid chamber 50, brake fluid from the fluid chamber 50 is supplied to the wheel cylinder 43 via the fluid passage 51, thereby increasing the fluid pressure in the wheel cylinder 43. That is, the electric cylinder 44 and the wheel cylinder 43 can transition the operating state of the front wheel electric braking devices 21, 22 between a contact state in which the friction portion 41 is in contact with the friction target portion 42, and a separation state in which the friction portion 41 is separated from the friction target portion 42. In the front wheel electric braking devices 21, 22, the electric cylinder 44 and the wheel cylinder 43 correspond to an "actuator" powered by the electric motor 71.

[0017] The control units 81, 82 control the electric motor 71 based on the braking force command value received from the overall control device 30. Specifically, the control units 81, 82 drive the electric motor 71 so that the braking force applied to the front wheels 11, 12 increases as the braking force command value increases. The specific configuration of the control units 81, 82 will be described later.

[0018] In the front wheel electric braking devices 21, 22, regenerative electric power may be generated in the electric motor 71. The regenerative electric power generated in the electric motor 71 is supplied to the power supply circuit. That is, the regenerative electric power generated in the electric motor 71 of the front wheel electric braking device 21 is supplied to the first power supply circuit 26. The regenerative electric power generated in the electric motor 71 of the front wheel electric braking device 22 is supplied to the second power supply circuit 27.

[0019] The electric motor 71 may generate regenerative power when the rotation direction and torque direction of the electric motor 71 are opposite to each other. This situation can occur when the control mode of the front wheel electric braking devices 21, 22 is switched. The control modes of the electric braking devices include a decrease mode that reduces the braking force applied to the wheels, a hold mode that holds the braking force, and an increase mode that increases the braking force. Control mode switches that generate regenerative power include a switch from the decrease mode to the hold mode, a switch from the decrease mode to the increase mode, a switch from the increase mode to the hold mode, and a switch from the increase mode to the decrease mode. Regenerative power is generated when the power generated by the operation of the electric motor 71 described above exceeds the power consumption due to copper loss in the electric motor 71.

[0020] <Rear wheel electric braking device> In this embodiment, the rear wheel electric braking devices 23, 24 are dry-type electric braking devices. Specifically, the rear wheel electric braking devices 23, 24 include a friction portion 61, a frictioned portion 62, an actuator 63, an electric motor 72, and a control unit. The control unit for the rear wheel electric braking device 23 for the left rear wheel 13 is referred to as "control unit 83," and the control unit for the rear wheel electric braking device 24 for the right rear wheel 14 is referred to as "control unit 84."

[0021] Since the frictional portion 62 rotates integrally with the rear wheels 13, 14, a braking force is applied to the rear wheels 13, 14 by bringing the frictional portion 61 into contact with the frictional portion 62. By increasing the force pressing the frictional portion 61 against the frictional portion 62, the braking force applied to the rear wheels 13, 14 increases.

[0022] The actuator 63 is operated using the electric motor 72 as a power source. Specifically, the actuator 63 operates to change the operating state of the rear wheel electric braking devices 23, 24 between a contact state and a separation state. The actuator 63 has a reduction mechanism 64 and a linear motion conversion mechanism 65. The reduction mechanism 64 reduces the rotational motion of the electric motor 72 and outputs it to the linear motion conversion mechanism 65. The linear motion conversion mechanism 65 converts the rotational motion input from the reduction mechanism 64 into linear motion and outputs it to the friction part 61. Therefore, in the rear wheel electric braking devices 23, 24, when the electric motor 72 is driven, the output torque of the electric motor 72 is transmitted to the friction part 61 via the actuator 63. This causes the friction part 61 to approach or separate from the friction part 62. When the friction part 61 comes into contact with the friction part 62, a frictional force is applied to the rear wheels 13, 14.

[0023] The control units 83, 84 control the electric motor 72 based on the braking force command value received from the overall control device 30. Specifically, the control units 83, 84 drive the electric motor 72 so that the braking force applied to the rear wheels 13, 14 increases as the braking force command value increases. The specific configuration of the control units 83, 84 will be described later.

[0024] In the rear wheel electric braking devices 23, 24, regenerative electric power may be generated in the electric motor 72. The regenerative electric power generated in the electric motor 72 is supplied to the power supply circuit. That is, the regenerative electric power generated in the electric motor 72 of the rear wheel electric braking device 23 is supplied to the second power supply circuit 27. The regenerative electric power generated in the electric motor 72 of the rear wheel electric braking device 24 is supplied to the first power supply circuit 26.

[0025] The electric motor 72 may generate regenerative electric power when the control mode of the rear wheel electric braking devices 23, 24 is switched. The situation in which the electric motor 72 generates regenerative electric power is the same as the situation in which the electric motor 71 generates regenerative electric power, so a detailed description thereof will be omitted here.

[0026] <Brake system control system> 2 is a block diagram showing the overall control device 30, the plurality of control units 81 to 84, and a CAN bus 86 provided in the vehicle 10. The overall control device 30 and the plurality of control units 81 to 84 are connected to the CAN bus 86. Therefore, the overall control device 30 can transmit and receive information to and from the plurality of control units 81 to 84 via the CAN bus 86. The plurality of control units 81 to 84 can transmit and receive information to and from each other via the CAN bus 86.

[0027] Each of the control units 81 to 84 has an execution unit 91 and a storage unit 92. For example, the execution unit 91 is a CPU. The storage unit 92 stores various control programs executed by the execution unit 91.

[0028] The plurality of execution units 91 execute a control program to function as a determination unit 101, a request unit 102, and a control unit 103, respectively. The determination unit 101 determines whether or not regenerative electric power is being generated in the electric motor associated with it. The electric motor associated with the determination unit 101 of the control unit 81 is the electric motor 71 of the front wheel electric braking device 21. The electric motor associated with the determination unit 101 of the control unit 82 is the electric motor 71 of the front wheel electric braking device 22. The electric motor associated with the determination unit 101 of the control unit 83 is the electric motor 72 of the rear wheel electric braking device 23. The electric motor associated with the determination unit 101 of the control unit 84 is the electric motor 72 of the rear wheel electric braking device 24.

[0029] In this embodiment, when the control mode of the electric braking device associated with itself is switched, the determination unit 101 determines that regenerative power is generated in the electric motor of the electric braking device. Specifically, the determination unit 101 determines that regenerative power is generated in the electric motor when any of the following conditions (A1), (A2), (A3), and (A4) is satisfied. (A1) The control mode of the electric braking device has switched from the reduction mode to the holding mode. (A2) The control mode of the electric braking device has switched from the decrease mode to the increase mode. (A3) The control mode of the electric braking device has switched from increase mode to hold mode. (A4) The control mode of the electric braking device has switched from increasing mode to decreasing mode.

[0030] When the determination unit 101 determines that the electric motor generates regenerative power, the request unit 102 requests the control unit 103 associated with the other electric motor to increase the amount of power consumed by the other electric motor. If the electric motor associated with the request unit 102 is referred to as a "first electric motor" and the electric motor other than the first electric motor that is connected to the same power supply circuit as the first electric motor is referred to as a "second electric motor," the other electric motor referred to here corresponds to the second electric motor. Therefore, the request unit 102 of the control unit 81 requests the control unit 103 of the control unit 84 to increase the amount of power consumed by the electric motor 72 of the rear wheel electric braking device 24. The request unit 102 of the control unit 82 requests the control unit 103 of the control unit 83 to increase the amount of power consumed by the electric motor 72 of the rear wheel electric braking device 23. The request section 102 of the control unit 83 requests the control section 103 of the control unit 82 to increase the amount of power consumed by the electric motor 71 of the front wheel electric braking device 22. The request section 102 of the control unit 84 requests the control section 103 of the control unit 81 to increase the amount of power consumed by the electric motor 71 of the front wheel electric braking device 21.

[0031] The control unit 103 controls the electric motor associated with itself based on the braking force command value received from the overall control device 30. In this embodiment, the control unit 103 controls the electric motor by vector control.

[0032] FIG. 3 is a diagram showing the rotating coordinate system of vector control. In the rotating coordinate system of vector control, the d-axis is the control axis extending in the direction of the magnetic flux axis of the permanent magnet of the electric motor, and the q-axis is the control axis extending in the direction of torque. In vector control, the control unit 103 drives the electric motor by adjusting the d-axis current Id, which is the current component in the direction of the d-axis, and the q-axis current Iq, which is the current component in the direction of the q-axis. Specifically, the control unit 103 derives a torque command value, which is a command value for the output torque of the electric motor, based on the braking force command value, and derives the d-axis current Id and the q-axis current Iq based on the torque command value. The control unit 103 then drives the electric motor by controlling the current flowing through each coil of the electric motor based on the d-axis current Id and the q-axis current Iq.

[0033] 3, the maximum torque curve CV1 is shown by a dashed line, and the torque command value isoline L1 is shown by a broken line. In the rotating coordinate system, when a current vector VC represented by the d-axis current Id and the q-axis current Iq points to the intersection P1 between the maximum torque curve CV1 and the isoline L1, the output torque of the electric motor can be set to the torque command value while minimizing the power consumption of the electric motor. In other words, when the current vector VC points to a point on the isoline L1 other than the intersection P1, the power consumption of the electric motor is higher than when the current vector VC points to the intersection P1.

[0034] As shown by the two-dot chain line in Figure 3, the current vector VC pointing to the intersection P1 is called the "reference current vector VCb." The d-axis current Id of the reference current vector VCb is called the "reference d-axis current Idb," and the q-axis current Iq of the reference current vector VCb is called the "reference q-axis current Iqb."

[0035] When the determination unit 101 associated with the first electric motor determines that the first electric motor generates regenerative power, the control unit 103 increases the amount of power consumed by the electric motor associated with itself (the second electric motor). That is, when the determination unit 101 associated with the first electric motor determines that the first electric motor generates regenerative power, the request unit 102 associated with the first electric motor requests the control unit 103 associated with the second electric motor to increase the amount of power consumed by the second electric motor. Therefore, when the request unit 102 associated with the first electric motor requests that the amount of power consumed by the second electric motor be increased, the control unit 103 associated with the second electric motor increases the amount of power consumed by the second electric motor. For example, when the request unit 102 of the control unit 84 requests that the amount of power consumed by the electric motor 71 of the front wheel electric braking device 21 be increased, the control unit 103 of the control unit 81 increases the amount of power consumed by the electric motor 71 of the front wheel electric braking device 21. In this example, the electric motor 71 of the front wheel electric braking device 21 corresponds to the "first electric motor," and the electric motor 72 of the rear wheel electric braking device 24 corresponds to the "second electric motor."

[0036] In this embodiment, when the operating state of the electric braking device corresponding to the control unit 103 is the abutting state, the control unit 103 increases the power consumption of the electric motor by performing d-axis current increasing control to increase the d-axis current Id. Specifically, in the d-axis current increasing control, the control unit 103 derives the d-axis current Id and the q-axis current Iq so that the absolute value of the d-axis current Id is greater than the absolute value of the reference d-axis current Idb. For example, the control unit 103 derives the d-axis current Id and the q-axis current Iq of the current vector VC shown by the solid line in FIG. 3. The power consumption of the electric motor when the control unit 103 performs the d-axis current increasing control is greater than the power consumption of the electric motor when the control unit 103 does not perform the d-axis current increasing control.

[0037] On the other hand, when the operation state of the electric braking device corresponding to itself is the separated state, the control unit 103 increases the amount of power consumed by the electric motor by implementing electric motor forced drive control that drives the electric motor within a range in which the operation state of the electric braking device is maintained in the separated state. Specifically, the control unit 103 drives the electric motor so that the friction part approaches the frictioned part or the friction part moves away from the frictioned part.

[0038] <Processing requests to increase power consumption> Referring to Figure 4, the power consumption increase request process, which is a process flow for requesting the control unit that controls the second electric motor to increase the amount of power consumed by the second electric motor, will be described. Figure 4 is a flowchart showing the power consumption increase request process. A control program corresponding to the power consumption increase request process is stored in the storage unit 92 of the control units 81 to 84. The control program is repeatedly executed by the execution unit 91 at a predetermined interval when braking force is being applied to the wheels by the operation of the electric braking device.

[0039] In step S11, the execution unit 91 acquires the control mode of the electric braking device corresponding to itself. Specifically, the execution unit 91 acquires the control mode based on the transition of the control amount of the electric motor (first electric motor) of the electric braking device corresponding to itself. The control amount of the electric motor is derived at predetermined intervals. Therefore, for example, the execution unit 91 acquires the decrease mode as the control mode when the latest value of the control amount is smaller than the previous value, acquires the increase mode as the control mode when the latest value of the control amount is greater than the previous value, and acquires the hold mode as the control mode when the latest value of the control amount is the same as the previous value.

[0040] In step S13, the execution unit 91 functions as the determination unit 101 to determine whether or not regenerative power is generated in the electric motor (first electric motor) of the electric braking device corresponding to itself. Specifically, the execution unit 91 determines whether or not any of the above conditions (A1) to (A4) is satisfied based on the control mode acquired in step S11 during the previous execution of the power consumption increase request process and the control mode acquired in step S11 this time. If the execution unit 91 determines that any of the conditions (A1) to (A4) is satisfied, it determines that regenerative power is generated in the electric motor. On the other hand, if the execution unit 91 determines that none of the conditions (A1) to (A4) is satisfied, it determines that regenerative power is not generated in the electric motor. If the execution unit 91 determines that regenerative power is generated in the electric motor (S13: YES), it proceeds to the process of step S15. If the execution unit 91 determines that regenerative power is not generated (S13: NO), it temporarily terminates the current process.

[0041] In step S15, the execution unit 91 functions as a request unit to request the control unit corresponding to the electric motor (second electric motor) connected to the same power supply circuit as the electric motor (first electric motor) of the electric braking device corresponding to the execution unit 91 to increase the amount of power consumption of the electric motor (second electric motor). Then, the execution unit 91 ends the current process.

[0042] <Increased power consumption processing> The power consumption increase process, which is a process flow for increasing the power consumption of the electric motor (second electric motor), will be described with reference to Figure 5. Figure 5 is a flowchart showing the power consumption increase process. A control program corresponding to the power consumption increase process is stored in the storage unit 92 of the control units 81 to 84. The control program is repeatedly executed by the execution unit 91 at a predetermined interval.

[0043] In step S21, the execution unit 91 determines whether or not the control unit corresponding to the other electric motor (first electric motor) has requested that the power consumption of the electric motor corresponding to itself (second electric motor) be increased. If the execution unit 91 has requested that the power consumption of the electric motor be increased (S21: YES), the execution unit 91 proceeds to the process of step S23, and if the execution unit 91 has not requested that the power consumption of the electric motor be increased (S21: NO), the execution unit 91 temporarily ends the current process.

[0044] In step S23, the execution unit 91 acquires the operation state of the electric braking device corresponding to itself. Specifically, the execution unit 91 acquires whether the operation state of the electric braking device is a contact state or a separation state.

[0045] In step S25, the execution unit 91 determines whether the operating state of the electric braking device acquired in step S23 is the contact state. If the operating state is the contact state (S25: YES), the execution unit 91 proceeds to the process of step S27, and if the operating state is the separation state (S25: NO), the execution unit 91 proceeds to the process of step S29.

[0046] In step S27, the execution unit 91 starts the above-described d-axis current increasing control by functioning as the control unit 103. After that, the execution unit 91 temporarily ends the current processing. In step S29, the execution unit 91 starts the above-described electric motor forced drive control by functioning as the control unit 103. After that, the execution unit 91 temporarily ends the current processing.

[0047] In addition, when the d-axis current increase control or the electric motor forced drive control is started by executing the power consumption increase process, the execution unit 91 carries out the control for a predetermined period of time and then ends the control.

[0048] <Actions and Effects of This Embodiment> (B1) The operation and effect when braking force is applied to the rear wheels 13, 14 by the rear wheel electric braking devices 23, 24 based on a command from the integrated control device 30 will be described.

[0049] For example, when the control mode of the rear wheel electric braking device 24 is switched, the control unit 84 of the rear wheel electric braking device 24 determines that regenerative electric power is being generated by the electric motor 72 of the rear wheel electric braking device 24. Because the rear wheel electric braking device 24 and the front wheel electric braking device 21 are connected to the common first power supply circuit 26 as shown in FIG. 1 , the control unit 84 requests the control unit 81 of the front wheel electric braking device 21 to increase the amount of power consumed by the electric motor 71 of the front wheel electric braking device 21.

[0050] When the control unit 81 receives the above request from the control unit 84, it drives the electric motor 71 of the front wheel electric braking device 21 to increase the amount of power consumed by the electric motor 71. At this time, if the front wheel electric braking device 21 is applying braking force to the left front wheel 11, the operation state of the front wheel electric braking device 21 is in the abutment state, so the control unit 81 executes d-axis current increase control. This increases the amount of power consumed by the electric motor 71 while suppressing fluctuations in the output torque of the electric motor 71 of the front wheel electric braking device 21. No fluctuations in the output torque of the electric motor 71 means that the braking force applied to the left front wheel 11 by the front wheel electric braking device 21 does not change. Regenerative electric power generated by the electric motor 72 of the rear wheel electric braking device 24 can be supplied to the electric motor 71 of the front wheel electric braking device 21 via the first power supply circuit 26. Therefore, by increasing the amount of power consumed by the electric motor 71 of the front wheel electric braking device 21, it is possible to suppress the increase in braking force applied to the left front wheel 11 while having the electric motor 72 of the rear wheel electric braking device 24 consume at least a portion of the regenerative power generated by the electric motor 71 of the front wheel electric braking device 21.

[0051] On the other hand, if the front electric braking device 21 is not applying braking force to the left front wheel 11 when the control unit 81 receives the above request, the operation state of the front electric braking device 21 is the disengaged state, and the control unit 81 therefore implements electric motor forced drive control. In this case, the electric motor 71 of the front electric braking device 21 is driven within a range that does not apply braking force to the left front wheel 11. Therefore, at least a portion of the regenerative electric power generated by the electric motor 72 of the rear electric braking device 24 can be consumed by the electric motor 71 of the front electric braking device 21 without applying braking force to the left front wheel 11.

[0052] In this case, the rear wheel electric braking device 24 corresponds to the "first electric braking device," and the electric motor 72 of the rear wheel electric braking device 24 corresponds to the "first electric motor." The control unit 84 of the rear wheel electric braking device 24 corresponds to the "first control device" corresponding to the first electric braking device, and the right rear wheel 14 corresponds to the "first wheel." The front wheel electric braking device 21 corresponds to the "second electric braking device," and the electric motor 71 of the front wheel electric braking device 21 corresponds to the "second electric motor." The control unit 81 of the front wheel electric braking device 21 corresponds to the "second control device" corresponding to the second electric braking device, and the left front wheel 11 corresponds to the "second wheel."

[0053] Incidentally, if it is determined that the electric motor 72 of the rear wheel electric braking device 23 generates regenerative electric power, the electric motor that consumes that regenerative electric power will be the electric motor 71 of the front wheel electric braking device 22. Therefore, in this case, the rear wheel electric braking device 23 corresponds to the "first electric braking device," and the electric motor 72 of the rear wheel electric braking device 23 corresponds to the "first electric motor." The control unit 83 of the rear wheel electric braking device 23 corresponds to the "first control device," and the left rear wheel 13 corresponds to the "first wheel." The front wheel electric braking device 22 corresponds to the "second electric braking device," and the electric motor 71 of the front wheel electric braking device 22 corresponds to the "second electric motor." The control unit 82 of the front wheel electric braking device 22 corresponds to the "second control device," and the right front wheel 12 corresponds to the "second wheel."

[0054] (B2) The operation and effect when braking force is applied to the front wheels 11, 12 by the front wheel electric braking devices 21, 22 based on a command from the integrated control device 30 will be described. For example, when the control mode of the front wheel electric braking device 22 is switched, the control unit 82 of the front wheel electric braking device 22 determines that regenerative power is being generated by the electric motor 71 of the front wheel electric braking device 22. Because the front wheel electric braking device 22 and the rear wheel electric braking device 23 are connected to the common second power supply circuit 27 as shown in FIG. 1 , the control unit 82 requests the control unit 83 of the rear wheel electric braking device 23 to increase the amount of power consumed by the electric motor 72 of the rear wheel electric braking device 23.

[0055] When the control unit 83 receives the above request from the control unit 82, it executes d-axis current increase control or electric motor forced drive control to increase the amount of power consumed by the electric motor 72. That is, when braking force is being applied to the left rear wheel 13 by the rear wheel electric braking device 23, the operating state of the rear wheel electric braking device 23 is the abutment state, so the control unit 83 executes d-axis current increase control. On the other hand, when braking force is not being applied to the left rear wheel 13 by the rear wheel electric braking device 23, the operating state of the rear wheel electric braking device 23 is the disengaged state, so the control unit 83 executes electric motor forced drive control. This allows at least a portion of the regenerative power generated by the electric motor 71 of the front wheel electric braking device 22 to be consumed by the electric motor 72 of the rear wheel electric braking device 23.

[0056] In this case, the front wheel electric braking device 22 corresponds to the "first electric braking device," and the electric motor 71 of the front wheel electric braking device 22 corresponds to the "first electric motor." The control unit 82 of the front wheel electric braking device 22 corresponds to the "first control device," and the right front wheel 12 corresponds to the "first wheel." The rear wheel electric braking device 23 corresponds to the "second electric braking device," and the electric motor 72 of the rear wheel electric braking device 23 corresponds to the "second electric motor." The control unit 83 of the rear wheel electric braking device 23 corresponds to the "second control device," and the left rear wheel 13 corresponds to the "second wheel."

[0057] Incidentally, if it is determined that the electric motor 71 of the front wheel electric braking device 21 generates regenerative electric power, the electric motor that consumes that regenerative electric power will be the electric motor 72 of the rear wheel electric braking device 24. Therefore, in this case, the front wheel electric braking device 21 corresponds to the "first electric braking device," and the electric motor 71 of the front wheel electric braking device 21 corresponds to the "first electric motor." The control unit 81 of the front wheel electric braking device 21 corresponds to the "first control device," and the left front wheel 11 corresponds to the "first wheel." The rear wheel electric braking device 24 corresponds to the "second electric braking device," and the electric motor 72 of the rear wheel electric braking device 24 corresponds to the "second electric motor." The control unit 84 of the rear wheel electric braking device 24 corresponds to the "second control device," and the right rear wheel 14 corresponds to the "second wheel."

[0058] In this embodiment, the following effects can be further obtained. (1) Consider a case where the control unit of the first electric braking device requests the control unit of the second electric braking device to increase the amount of power consumed by the second electric motor after the first electric motor actually generates regenerative power. In this case, the start of d-axis current increase control or electric motor forced drive control to increase the amount of power consumed by the second electric motor may be delayed relative to the generation of regenerative power by the first electric motor, which could prevent the second electric motor from consuming the regenerative power generated by the first electric motor.

[0059] In this regard, in this embodiment, it is determined that regenerative power will be generated in the electric motor of the electric braking device when any of the above conditions (A1) to (A4) is satisfied. Therefore, before regenerative power is actually generated in the first electric motor, the control unit of the second electric braking device can start d-axis current increase control and electric motor forced drive control in preparation for the second electric motor to consume the regenerative power. This makes it possible to prevent a delay in the start of an increase in power consumption by the second electric motor relative to the generation of regenerative power in the first electric motor, and ultimately allows the second electric motor to consume the regenerative power generated in the first electric motor.

[0060] (Second embodiment) A second embodiment of the brake system will be described with reference to Figures 6 to 8. The second embodiment differs from the first embodiment in that there is only one power supply circuit, that a single front wheel electric braking device is able to apply braking force to both front wheels 11, 12, and in the content of control. In the following explanation, differences from the first embodiment will be mainly described, and the same reference numerals will be used to designate the same components as in the first embodiment, and redundant explanations will be omitted.

[0061] 6 is a schematic diagram showing a brake system 20A of this embodiment. The brake system 20A includes a front wheel electric braking device 21A, two rear wheel electric braking devices 23, 24, a power supply circuit 26A, and an overall control device 30A. The power supply circuit 26A supplies power to the rear wheel electric braking devices 23, 24 and the front wheel electric braking device 21A.

[0062] <Front wheel electric braking device> The front wheel electric braking device 21A has an electric cylinder 44A, an electric motor 71A, and a control unit 80A. The electric cylinder 44A is an electric pressure device that operates using the electric motor 71A as a power source. The electric cylinder 44A has a larger cylinder volume than the cylinder 48 of the electric cylinder 44 described in the first embodiment, but other than that, the configuration of the electric cylinder 44A is generally the same as that of the electric cylinder 44, and therefore a detailed description thereof will be omitted. The fluid chamber 50A of the electric cylinder 44A is connected to both the wheel cylinder 43 provided for the left front wheel 11 and the wheel cylinder 43 provided for the right front wheel 12 via a fluid passage 51A. Therefore, the electric cylinder 44A can adjust the fluid pressure in both the wheel cylinder 43 for the left front wheel 11 and the wheel cylinder 43 for the right front wheel 12. In this embodiment, the electric cylinder 44A, the wheel cylinder 43 for the left front wheel 11, and the wheel cylinder 43 for the right front wheel 12 correspond to an "actuator" powered by the electric motor 71A.

[0063] The control unit 80A drives the electric motor 71A based on the braking force command value received from the overall control device 30A. The specific configuration of the control unit 80A will be described later. <Brake system control system> FIG. 7 is a block diagram showing the overall control device 30A, a plurality of control units 80A, 83, 84, and a CAN bus 86.

[0064] The overall control device 30A has an execution unit 31 and a storage unit 32. For example, the execution unit 31 is a CPU. The storage unit 32 stores various control programs executed by the execution unit 31.

[0065] Each of the control units 80A, 83, and 84 has an execution unit 91 and a storage unit 92. For example, the execution unit 91 is a CPU. The storage unit 92 stores various control programs executed by the execution unit 91.

[0066] In this embodiment, the execution unit 31 of the overall control device 30A executes a control program stored in the storage unit 32, thereby functioning as a command unit 106A, a determination unit 101A, a selection unit 104A, and a request unit 102A. The execution units 91 of the multiple control units 80A, 83, and 84 each function as a control unit 103 by executing a control program stored in the storage unit 92. The processing content of the control unit 103 is the same as in the first embodiment, so a description of the control unit 103 will be omitted here.

[0067] The command unit 106A derives a braking force command value, which is a command value for the braking force to be applied to the wheels 11 to 14 by the electric braking devices 21A, 23, and 24. Specifically, the command unit 106A derives the braking force command value based on the amount of brake operation by the driver of the vehicle 10 and requests from other control devices. Then, the command unit 106A transmits the derived braking force command value to the control unit 103 of the electric braking devices 21A, 23, and 24.

[0068] The determination unit 101A determines whether or not regenerative electric power is being generated in the plurality of electric motors 71A, 72. Specifically, if any of the above conditions (A1) to (A4) is met in the front wheel electric braking device 21A, the determination unit 101A can determine that the control mode of the front wheel electric braking device 21A has switched, and therefore determines that regenerative electric power is being generated in the electric motor 71A. Similarly, if any of the above conditions (A1) to (A4) is met in the rear wheel electric braking device 23, the determination unit 101A determines that regenerative electric power is being generated in the electric motor 72 of the rear wheel electric braking device 23. If any of the above conditions (A1) to (A4) is met in the rear wheel electric braking device 24, the determination unit 101A determines that regenerative electric power is being generated in the electric motor 72 of the rear wheel electric braking device 24. In this embodiment, an electric motor determined by the determination unit 101A to generate regenerative power is referred to as a "power generating motor," and an electric motor determined by the determination unit 101A not to generate regenerative power is referred to as a "non-power generating motor."

[0069] If there is a power-generating motor among the multiple electric motors 71A, 72, the selection unit 104A selects a power-consuming motor, which is an electric motor that consumes regenerated power, from among the non-power-generating motors based on the operating states of electric braking devices that have non-power-generating motors. For example, if the determination unit 101A determines that the electric motor 71A of the front wheel electric braking device 21A generates regenerative power, the selection unit 104A selects a power-consuming motor, which is an electric motor that consumes regenerated power generated by the electric motor 71A, from among the multiple electric motors 72, based on the operating states of the multiple rear wheel electric braking devices 23, 24. In this example, the electric motor 71A of the front wheel electric braking device 21A corresponds to the "power-generating motor," and the multiple electric motors 72 correspond to the "non-power-generating motors."

[0070] In this embodiment, when there is only one non-power-generating motor, the selection unit 104A selects the non-power-generating motor as the power-consuming motor. On the other hand, when there are multiple non-power-generating motors, the selection unit 104A selects at least one of the multiple non-power-generating motors as the power consuming motor. For example, when there is an electric brake device in a disengaged state among the electric brake devices having non-power-generating motors, the selection unit 104A selects the electric motor of that electric brake device as the power-consuming motor. On the other hand, when there is no electric brake device in a disengaged state among the electric brake devices having non-power-generating motors, the selection unit 104A selects the power-consuming motor according to a predetermined rule.

[0071] The predetermined rule may be, for example, to select the electric motor with the lowest rotation speed as the power consuming motor, or to select the electric motor with the smallest torque command value as the power consuming motor.

[0072] The request unit 102A requests the control unit 103 corresponding to the electric motor selected as an electric motor by the selection unit 104A as an electric power consuming motor to increase the amount of electric power consumed by that electric motor. For example, if the electric motor 72 of the rear wheel electric braking device 23 is selected as an electric power consuming motor by the selection unit 104A, the request unit 102A requests the control unit 103 of the rear wheel electric braking device 23 to increase the amount of electric power consumed by the electric motor 72 of the rear wheel electric braking device 23.

[0073] <Processing requests to increase power consumption> The power consumption increase request process executed in this embodiment will be described with reference to Fig. 8. Fig. 8 is a flowchart showing the power consumption increase request process. A control program corresponding to the power consumption increase request process is stored in the storage unit 32 of the overall control device 30A. The control program is repeatedly executed at a predetermined interval by the execution unit 31 of the overall control device 30A.

[0074] In step S41, the execution unit 31 acquires the control modes of the multiple electric braking devices 21A, 23, and 24. Specifically, the execution unit 31 acquires the control modes based on the transition of the electric motors obtained by acquiring the control amounts of the electric motors of the electric braking devices from the control units 80A, 83, and 84 at predetermined intervals.

[0075] In step S43, the execution unit 31 functions as the determination unit 101A to determine whether or not there is a power generating motor, which is an electric motor determined to generate regenerative power, among the multiple electric motors 71A, 72. If there is a power generating motor (S43: YES), the execution unit 31 proceeds to the processing of step S45, and if there is no power generating motor (S43: NO), the execution unit 31 temporarily ends the current processing.

[0076] In step S45, the execution unit 31 functions as the selection unit 104A to determine whether there are any wheels to which braking force is not being applied by the electric braking device. If there are any wheels to which braking force is not being applied by the electric braking device (S45: YES), the execution unit 31 proceeds to the processing of step S47, and if there are no wheels to which braking force is not being applied by the electric braking device (S45: NO), the execution unit 31 proceeds to the processing of step S49. In this embodiment, wheels to which braking force is not being applied by the electric braking device are referred to as "non-braked wheels."

[0077] In step S47, the execution unit 31 functions as the selection unit 104A to select the electric motor of the electric braking device corresponding to the non-braked wheel as the power consuming motor. Then, the execution unit 31 proceeds to the process of step S51.

[0078] In step S49, the execution unit 31 functions as the selection unit 104A to select a power-consuming motor in accordance with the predetermined rule, and then the execution unit 31 proceeds to the process of step S51.

[0079] In step S51, the execution unit 31 functions as the request unit 102A to request the control unit corresponding to the electric motor selected as the power-consuming motor in step S47 or step S49 to increase the amount of power consumed by the electric motor. Then, the execution unit 31 temporarily ends the current process.

[0080] <Actions and Effects of This Embodiment> (B3) The operation and effect when braking force is applied to both front wheels 11, 12 by the front wheel electric braking device 21A based on a command from the integrated control device 30 will be described.

[0081] For example, when the control mode of the front wheel electric braking device 21A is switched, the overall control device 30A determines that the electric motor 71A of the front wheel electric braking device 21A is generating regenerative power. In other words, the electric motor 71A corresponds to the power generating motor. The electric motors 72 other than the electric motor 71A corresponding to the power generating motor are connected to the same power supply circuit 26A as the electric motor 71A. Therefore, it is required to increase the amount of power consumed by at least one of the two electric motors 72.

[0082] Specifically, it is determined whether or not there is a rear wheel electric braking device among the two rear wheel electric braking devices 23, 24 that is not applying braking force to the rear wheels. If neither of the two rear wheel electric braking devices 23, 24 is applying braking force to the rear wheels, both of the two electric motors 72 are selected as power-consuming motors. If only one of the two rear wheel electric braking devices 23, 24 is not applying braking force to the rear wheels, only the electric motor 72 of that one rear wheel electric braking device is selected as a power-consuming motor. In this case, the electric motor 72 of the rear wheel electric braking device that is applying braking force to the rear wheels is not selected as a power-consuming motor. If both of the two rear wheel electric braking devices 23, 24 are applying braking force to the rear wheels, at least one of the two electric motors 72 is selected as a power-consuming motor in accordance with a predetermined rule.

[0083] When an electric motor is selected as an electric power consuming motor in this manner, the overall control device 30A requests the control unit corresponding to the electric motor 72 selected as the electric power consuming motor to increase the amount of electric power consumed by that electric motor 72. For example, if the electric motor 72 of the rear wheel electric braking device 23 is selected as the electric power consuming motor, the control unit 83 of the rear wheel electric braking device 23 is requested to increase the amount of electric power consumed by the electric motor 72.

[0084] When the integrated control device 30A requests an increase in the power consumption of the electric motor 72, the control units 82, 83 drive the electric motor 72 corresponding to that unit to increase the power consumption of that electric motor 72. For example, when the operating state of the rear wheel electric braking device is in the abutment state, the control units 82, 83 execute d-axis current increase control. Also, when the operating state of the rear wheel electric braking device is in the separation state, the control units 82, 83 execute electric motor forced drive control. This allows at least a portion of the regenerative power generated by the electric motor 71A of the front wheel electric braking device 21A to be consumed by electric motors 72 other than the electric motor 71A.

[0085] Note that the operation when an electric motor other than the electric motor 71A of the front wheel electric braking device 21A serves as the electric power generating motor is substantially the same as in the above case (B3), and therefore a description thereof will be omitted here.

[0086] Furthermore, in this embodiment, it is possible to obtain the same effect as that (1) of the first embodiment. (Example of change) The above-described embodiments can be modified as follows: The above-described embodiments and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

[0087] In the above embodiments, the determination unit 101 may determine that the electric motor generates regenerative power based on the rotation direction and torque direction of the electric motor, in addition to or instead of switching the control mode. Specifically, the determination unit 101 may determine that the electric motor generates regenerative braking force when the rotation direction and torque direction of the electric motor are opposite to each other. In this case, the rotation direction of the electric motor may be derived, for example, from the output signal of a rotation angle sensor that detects the rotation angle of the electric motor. Furthermore, the torque direction of the electric motor may be derived, for example, from a torque command value.

[0088] In the second embodiment, the determination unit 101A only needs to determine whether regenerative power is generated in at least one of the electric motors 71A and 72. For example, if the determination unit 101A determines whether regenerative power is generated in the electric motors 72, it does not need to determine whether regenerative power is generated in the electric motor 71A. Also, for example, if the determination unit 101A determines whether regenerative power is generated in the electric motor 71A, it does not need to determine whether regenerative power is generated in the electric motor 72.

[0089] In the second embodiment, the selection unit 104A may select all electric motors other than the power-consuming motors among the plurality of electric motors 71A, 72 as power-consuming motors.

[0090] In the second embodiment, the overall control device 30A functions as the determination unit 101A, but this is not limiting. That is, the multiple control units 80A, 83, and 84 may each function as a determination unit. In this case, the multiple control units 80A, 83, and 84 may each function as a selection unit, or the multiple control units 80A, 83, and 84 may each function as a selection unit and a request unit.

[0091] In the first embodiment, the plurality of control units 81 to 84 function as the determination unit 101 and the request unit 102, respectively, but this is not limiting. For example, the overall control device 30 may function as the determination unit and the request unit.

[0092] In the first embodiment, the control units 81 to 84 do not have to function as the request unit 102. In this case, when the determination unit 101 determines that regenerative power is being generated in the electric motor, the determination result may be transmitted to another control unit, and the other control unit may then perform d-axis current increase control or electric motor forced drive control.

[0093] In the above embodiments, when the amount of power consumed by the electric motor is increased, the d-axis current increase control may be performed regardless of whether the operating state of the electric braking device is the separation state or the contact state.

[0094] In the second embodiment, the brake system may be configured to include the two front wheel electric braking devices 21, 22 shown in FIG. 1 instead of the front wheel electric braking device 21A. In the first embodiment, the front wheel electric braking device that applies braking force to the front wheels 11, 12 may be a dry type electric braking device like the rear wheel electric braking devices 23, 24.

[0095] In the above embodiments, the rear wheel electric braking device that applies braking force to the rear wheels 13, 14 may be a wet type electric braking device like the front wheel electric braking devices 21, 22. In the first embodiment, the first power supply circuit 26 and the second power supply circuit 27 are provided as power supply circuits, but only one power supply circuit is required. In this case, power is supplied to the multiple electric braking devices 21 to 24 from the single power supply circuit. Therefore, the execution units 91 of the multiple control units 81 to 84 may function as selection units. In other words, the execution unit 91 executes a process equivalent to the power consumption increase request process shown in FIG. 8.

[0096] In the first embodiment, the rear wheel electric braking device 23 and the rear wheel electric braking device 24 may be connected to a common first power supply circuit, and the front wheel electric braking device 21 and the front wheel electric braking device 22 may be connected to a common second power supply circuit.

[0097] In the above-described embodiments, the rear wheel electric braking device 23 is provided with a control unit 83, and the rear wheel electric braking device 24 is provided with a control unit 84, but the rear wheel electric braking device 23 and the rear wheel electric braking device 24 may be controlled by a common control unit.

[0098] In the first embodiment, the front wheel electric braking device 21 is provided with a control unit 81, and the front wheel electric braking device 22 is provided with a control unit 82, but the front wheel electric braking devices 21 and 22 may also be controlled by a common control unit.

[0099] In the above embodiments, a control unit is provided for each electric braking device, and the control unit controls the electric motor of the electric braking device. However, this is not limited to this. For example, the electric braking device may be configured without a control unit. In this case, the overall control device 30, 30A controls the electric motors of the multiple electric braking devices.

[0100] The overall control device 30, 30A and the control units 81-84, 80A may be configured as circuits including one or more processors operating according to a computer program, one or more dedicated hardware circuits such as dedicated hardware for performing at least some of the various processes, or a combination thereof. Examples of dedicated hardware include an application-specific integrated circuit (ASIC). The processor includes a CPU and memory such as RAM and ROM, which stores program code or instructions configured to cause the CPU to perform the processes. The memory, i.e., storage medium, includes any available medium accessible by a general-purpose or dedicated computer.

[0101] (Other technical ideas) Next, the technical ideas that can be understood from the above-described embodiment and modified examples will be described. (A) the first electric braking device has control modes including a decrease mode for decreasing the braking force applied to the wheel, a hold mode for holding the braking force, and an increase mode for increasing the braking force; It is preferable that the determination unit determine that regenerative electric power is generated in the first electric motor when the control mode of the first electric braking device is switched.

[0102] (b) It is preferable that the determination unit determines that regenerative power is generated in the first electric motor when any of the following occurs: the control mode of the first electric braking device has switched from the decrease mode to the hold mode; the control mode of the first electric braking device has switched from the decrease mode to the increase mode; the control mode of the first electric braking device has switched from the increase mode to the hold mode; or the control mode of the first electric braking device has switched from the increase mode to the decrease mode.

[0103] (c) It is preferable that the determination unit determines that regenerative power is generated in the electric motor of the electric braking device when any of the following occurs: the control mode of the electric braking device has switched from the decrease mode to the hold mode; the control mode of the electric braking device has switched from the decrease mode to the increase mode; the control mode of the electric braking device has switched from the increase mode to the hold mode; or the control mode of the electric braking device has switched from the increase mode to the decrease mode.

[0104] The expression "at least one" used herein means "one or more" of the desired options. As an example, the expression "at least one" used herein means "only one option" or "both of two options" if the number of options is two. As another example, the expression "at least one" used herein means "only one option" or "any combination of two or more options" if the number of options is three or more. [Explanation of symbols]

[0105] 10...Vehicle 11~14...Wheel 20,20A...Brake system 21~24,21A…Electric braking device 26,26A,27…Power circuit 30...Overall control device 41,61...Friction part 42,62…Frictioned part 43...Wheel cylinder (an example of an actuator) 44, 44A... Electric cylinder (an example of an actuator) 63...Actuator 71, 71A, 72... Electric motors 80A, 81 to 84...Control unit (an example of a control device) 101,101A...judgment section 102,102A…Request part 103...Control unit 104A…Selection section

Claims

1. The present invention is applied to a vehicle having a first wheel and a second wheel as wheels, a first electric braking device that applies a braking force to the first wheel, and a second electric braking device that applies a braking force to the second wheel, the first electric braking device and the second electric braking device apply braking force to the wheel by bringing a friction portion into contact with a friction target portion, and each have an actuator that transitions the operating state of the electric braking device between a contact state in which the friction portion is in contact with the friction target portion and a separation state in which the friction portion is separated from the friction target portion, In a brake system in which a first electric motor that is a power source for the actuator of the first electric braking device and a second electric motor that is a power source for the actuator of the second electric braking device are connected to a common power supply circuit, a determination unit that determines whether regenerative power is generated in the first electric motor; a control unit that increases the amount of power consumed by the second electric motor when the determination unit determines that regenerative power is generated in the first electric motor; A brake system comprising:

2. The control unit controlling a d-axis component current and a q-axis component current to the second electric motor by vector control; When the determination unit determines that regenerative power is generated in the first electric motor, the absolute value of the current of the d-axis component in the vector control is increased to increase the amount of power consumed by the second electric motor.

10. The braking system of claim 1.

3. The control unit when the determination unit determines that regenerative electric power is being generated by the first electric motor and the operation state of the second electric braking device is the separated state, increasing the amount of power consumed by the second electric motor by driving the second electric motor within a range in which the operation state of the second electric braking device is maintained in the separated state; 3. A brake system according to claim 1 or 2.

4. a first control device corresponding to the first electric braking device and a second control device corresponding to the second electric braking device, The first control device The determination unit is included, a request unit that requests the control unit to increase the amount of power consumed by the second electric motor when the determination unit determines that regenerative power is generated by the first electric motor; The second control device is The control unit is provided. the control unit increases the amount of power consumption of the second electric motor when the request unit requests an increase in the amount of power consumption of the second electric motor. A brake system according to any one of claims 1 to 3.

5. Applicable to vehicles with three or more wheels, three or more electric braking devices corresponding to the three or more wheels; the three or more electric braking devices apply braking force to the wheels by bringing frictional portions into contact with frictioned portions, and each of the three or more electric braking devices has an actuator that transitions the operating state of the electric braking device between a contact state in which the frictional portion is in contact with the frictioned portion and a separation state in which the frictional portion is separated from the frictioned portion, In a brake system, electric motors that are power sources of the three or more actuators are connected to a common power supply circuit, a determination unit that determines whether regenerative power is generated in at least one of the three or more electric motors; a selection unit that selects, based on an operating state of the electric braking device having an electric motor other than the power generating motor, an electric motor that consumes the regenerative power generated by the power generating motor, from the electric motors other than the power generating motor, based on an operating state of the electric braking device having an electric motor other than the power generating motor that is determined by the determination unit to generate regenerative power; a control unit that increases the amount of power consumed by the power-consuming motor selected by the selection unit when the determination unit determines that regenerative power is generated in any of the three or more electric motors; A brake system comprising:

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