Brake system

Abstract

Provided is a brake system (1) wherein a first brake system (50) is provided with a first main hydraulic pressure path (51) and a switching valve (56) provided in the first main hydraulic pressure path (51). A second brake system (60) is provided with a third main hydraulic pressure path (61). A connecting hydraulic pressure path (71) leads from the first main hydraulic pressure path (51) to the third main hydraulic pressure path (61). When energized, the switching valve (56) assumes a state in which the first main hydraulic pressure path (51) and the connecting hydraulic pressure path (71) do not communicate with each other. When not energized, the switching valve (56) assumes a state in which the first main hydraulic pressure path (51) and the connecting hydraulic pressure path (71) communicate with each other. In this configuration, even when a first brake unit (10) is not actuated, hydraulic braking pressure can be applied to a wheel brake of the first brake unit (10).

Description

Technical Field

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

Background Art

[0002] As a braking system, there is one that has a hydraulic pressure generating device that drives an electric motor according to the stroke amount of a brake pedal to generate hydraulic pressure, and two brake systems connected to the hydraulic pressure generating device, and applies the hydraulic pressure from one hydraulic pressure generating device to the two brake systems (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] From the viewpoint of fail-safe and the like, as shown in FIG. 6, a braking system 100 is desired that includes two brake units 10, 20 each having a hydraulic pressure generating device 12, 22, a brake system 50, 60, and an electronic control device 14, 24, and independently controls both brake units 10, 20. In this braking system 100, two wheel brakes B1, B2 on the front wheel FR, FL side are connected to one brake unit 10, and two wheel brakes B3, B4 on the rear wheel RR, RL side are connected to the other brake unit 20.

[0005]

[0006] ​The present invention aims to solve the aforementioned problems and provide a brake system that can apply brake fluid pressure to the two wheel brakes of the first brake unit even when the electronic control device or hydraulic pressure generator of the first brake unit is not operating. [Means for solving the problem]

[0007] To solve the aforementioned problems, the present invention provides a brake system comprising a first brake unit, a second brake unit, and a connecting hydraulic pressure passage connecting the first brake unit and the second brake unit. The first brake unit includes a first hydraulic pressure generator that generates brake fluid pressure according to the amount of operation of a brake lever, a first brake system, and a first electronic control device that controls the first hydraulic pressure generator and the first brake system. The first brake system includes a first main hydraulic pressure passage from the first hydraulic pressure generator to the first wheel brake, a second main hydraulic pressure passage from the first main hydraulic pressure passage to the second wheel brake, and a switching valve provided in the first main hydraulic pressure passage. The second main hydraulic pressure passage communicates with the first main hydraulic pressure passage on the first wheel brake side of the switching valve. The second brake unit includes a second hydraulic pressure generator that generates brake fluid pressure according to the amount of operation of the brake lever, a second brake system, and a second electronic control device that controls the second hydraulic pressure generator and the second brake system. The second brake system comprises a third main hydraulic path from the second hydraulic pressure generator to the third wheel brake, and a fourth main hydraulic path from the third main hydraulic path to the fourth wheel brake, with the connecting hydraulic path extending from the first main hydraulic path to the third main hydraulic path. When energized, the switching valve connects the first hydraulic pressure generator side and the first wheel brake side of the first main hydraulic path, while the first main hydraulic path and the connecting hydraulic path are not connected. When not energized, the switching valve connects the first hydraulic pressure generator side and the first wheel brake side of the first main hydraulic path, while the first main hydraulic path and the connecting hydraulic path are connected.

[0008] In the brake system of the present invention, when the switching valve is not energized, the brake fluid pressure generated by the second hydraulic pressure generator is transmitted to the third main hydraulic pressure passage and also transmitted from the connecting hydraulic pressure passage to the first main hydraulic pressure passage via the switching valve. As a result, even if the first electronic control unit or the first hydraulic pressure generator of the first brake unit is not operating, brake fluid pressure can be applied to the two wheel brakes of the first brake unit, and braking force can be generated on both wheel brakes of the first brake unit.

[0009] In the aforementioned braking system, it is preferable to provide the first wheel brake and the second wheel brake on the left and right front wheels, respectively, and the third wheel brake and the fourth wheel brake on the left and right rear wheels, respectively. In this configuration, even if the first electronic control unit or the first hydraulic pressure generator of the first brake unit does not operate, a large braking force is generated in the wheel brakes of both the left and right front wheels, allowing the vehicle to be braked while remaining stable.

[0010] In the brake system described above, it is preferable that the first brake system includes a first inlet valve for opening and closing the first main hydraulic passage, a second inlet valve for opening and closing the second main hydraulic passage, a return passage from the first main hydraulic passage and the second main hydraulic passage to a reservoir tank, and an outlet valve for opening and closing the return passage.

[0011] In this configuration, opening the inlet valve and closing the outlet valve allows the brake fluid pressure generated by the hydraulic pressure generator to be transmitted to the wheel brakes (during normal braking or when the pressure is increased in anti-lock brake control). Conversely, closing the inlet valve and opening the outlet valve reduces the brake fluid pressure transmitted to the wheel brakes (when the pressure is reduced in anti-lock brake control). Furthermore, closing both the inlet and outlet valves maintains the brake fluid pressure transmitted to the wheel brakes (when the pressure is maintained in anti-lock brake control).

[0012] In the aforementioned brake system, it is preferable to set the drive amount of the second hydraulic pressure generator to be greater when the switching valve is de-energized than when the switching valve is energized. Furthermore, it is preferable to set the drive amount of the second hydraulic pressure generator to be increased based on the required fluid volume when the switching valve is de-energized. In this configuration, even if the electronic control device or hydraulic pressure generator of the first brake unit is not operating, the second hydraulic pressure generator of the second brake unit alone can provide the same brake fluid pressure to both wheel brakes of the first brake unit as under normal conditions.

[0013] In the aforementioned braking system, the first rear wheel is provided with the third wheel brake and the first electric brake, and the second rear wheel is provided with the fourth wheel brake and the second electric brake. The second braking system is also provided with a third inlet valve that opens and closes the third main hydraulic passage and a fourth inlet valve that opens and closes the fourth main hydraulic passage. When the switching valve is not energized, the third and fourth inlet valves are closed and the first and second electric brakes are activated.

[0014] In this configuration, if the first electronic control unit and the first hydraulic pressure generator of the first brake unit are not operating and the switching section is de-energized, the brake fluid pressure generated by the second hydraulic pressure generator is not transmitted to the third main hydraulic pressure passage, but is entirely transmitted to the first main hydraulic pressure passage. This allows for a greater braking force from the wheel brakes on the two front wheels. In addition, the two rear wheels can be braked by the first electric brake and the second electric brake.

[0015] In the aforementioned brake system, if the switching valve is configured as a three-way valve, two brake systems can be connected while keeping the number of solenoid valves low.

[0016] In the aforementioned brake system, the first hydraulic pressure generator and the second hydraulic pressure generator are configured to generate brake fluid pressure by moving a piston within a cylinder using an electric motor. The first main hydraulic pressure passage is connected to the cylinder of the first hydraulic pressure generator, and the third main hydraulic pressure passage is connected to the cylinder of the second hydraulic pressure generator. During normal brake operation, brake fluid pressure is supplied from the first hydraulic pressure generator to the first wheel brake and the second wheel brake, and from the second hydraulic pressure generator to the third wheel brake and the fourth wheel brake.

[0017] In the aforementioned brake system, the second electronic control device may be configured to switch between energized and de-energized states of the switching valve. Furthermore, the second electronic control unit may be configured to switch between energized and de-energized states of the switching valve based on the detection of operation of the first brake unit. In this configuration, for example, if the second electronic control unit detects a malfunction in the first brake unit, the second electronic control unit can de-energize the switching valve, thereby allowing brake fluid pressure to be supplied from the second hydraulic pressure generator to the brakes on both wheels of the first brake unit. [Effects of the Invention]

[0018] In the brake system of the present invention, even if the electronic control device or hydraulic pressure generator of the first brake unit is not operating, brake fluid pressure can be applied to the two wheel brakes of the first brake unit to brake the vehicle. [Brief explanation of the drawing]

[0019] [Figure 1] This is a configuration diagram showing a brake system according to an embodiment of the present invention. [Figure 2] This is a diagram showing the configuration of a brake system according to an embodiment of the present invention during normal brake operation. [Figure 3]In the braking system according to an embodiment of the present invention, it is a configuration diagram when the first electronic control device and the first hydraulic pressure generating device of the first braking unit do not operate. [Figure 4] It is a graph showing the change in the brake hydraulic pressure generated by the hydraulic pressure generating device in the braking system according to an embodiment of the present invention. [Figure 5] In the braking system according to an embodiment of the present invention, it is a configuration diagram when brake hydraulic pressure is applied only to the wheel brakes of the first braking unit in a state where the first electronic control device and the first hydraulic pressure generating device of the first braking unit do not operate. [Figure 6] It is a configuration diagram showing a reference form of the braking system.

Mode for Carrying Out the Invention

[0020] Embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the present embodiment, a case where the braking system of the present invention is applied to a four-wheeled vehicle will be described as an example. As shown in FIG. 1, the braking system 1 is a by-wire braking system that operates when the prime mover (such as an engine or an electric motor) is started. The braking system 1 can be mounted on a hybrid vehicle that uses a motor in combination, an electric vehicle or a fuel cell vehicle that uses only a motor as a power source, or a vehicle that uses only an engine (internal combustion engine) as a power source.

[0021] The braking system 1 includes a first braking unit 10 to which a first wheel brake B1 and a second wheel brake B2 are connected, a second braking unit 20 to which a third wheel brake B3 and a fourth wheel brake B4 are connected, and a connecting hydraulic passage 71. In the present embodiment, the first wheel brake B1 brakes the left front wheel FL, and the second wheel brake B2 brakes the right front wheel FR. Also, the third wheel brake B3 brakes the left rear wheel RL, and the fourth wheel brake B4 brakes the right rear wheel RR. Thus, the braking system 1 of the present embodiment has a brake structure of an H-piping. In this embodiment, a first electric brake EB1, which functions as a parking brake, is provided on the left rear wheel RL, and a second electric brake EB2, which functions as a parking brake, is provided on the right rear wheel RR.

[0022] The first brake unit 10 includes a first base 11, a first hydraulic pressure generator 12, a first brake system 50, a first reservoir tank 13, and a first electronic control unit 14. The first base 11 is a metal block mounted on the vehicle. Multiple flow channels are formed inside the first base 11.

[0023] The first hydraulic pressure generator 12 is an electric actuator that generates brake fluid pressure according to the stroke amount (operation amount) of the brake pedal P (brake operator). The first hydraulic pressure generator 12 is attached to the first base 11. The first hydraulic pressure generator 12 generates brake fluid pressure by moving a piston 12b inside a cylinder 12c using an electric motor 12a as the drive source.

[0024] The first reservoir tank 13 is a container for supplying brake fluid to the first hydraulic pressure generator 12 and is attached to the first base 11. Brake fluid is supplied from the first reservoir tank 13 to the cylinder 12c of the first hydraulic pressure generator 12 through a passage in the first base 11.

[0025] The first brake system 50 includes a first main hydraulic passage 51, a second main hydraulic passage 52, and a first return hydraulic passage 53, all of which are formed within the first base body 11. The first main hydraulic passage 51 is a passage from the first hydraulic generator 12 to the wheel cylinder of the first wheel brake B1. The second main hydraulic passage 52 is a passage from the first main hydraulic passage 51 to the wheel cylinder of the second wheel brake B2. The first main hydraulic passage 51 is connected to the cylinder 12c of the first hydraulic generator 12, and brake fluid pressure is supplied from the first hydraulic generator 12 to the first main hydraulic passage 51 and the second main hydraulic passage 52.

[0026] The first return fluid passage 53 is a flow path from the first main hydraulic passage 51 and the second main hydraulic passage 52 to the first reservoir tank 13. The first return fluid passage 53 comprises a first branch fluid passage 54 branching from the first main hydraulic passage 51 and a second branch fluid passage 55 branching from the second main hydraulic passage 52. The first branch fluid passage 54 and the second branch fluid passage 55 merge to form a single fluid passage. In other words, the first return fluid passage 53 comprises the first branch fluid passage 54 and the second branch fluid passage 55, which communicate with the first main hydraulic passage 51 and the second main hydraulic passage 52, respectively, and a fluid passage from the confluence point of the first branch fluid passage 54 and the second branch fluid passage 55 to the first reservoir tank 13. Brake fluid released from the first wheel brake B1 and the second wheel brake B2 flows into the first return fluid passage 53. The brake fluid released into the first return fluid passage 53 is returned to the first reservoir tank 13 through the first return fluid passage 53.

[0027] In the first main hydraulic passage 51, a switching valve 56 is provided on the side of the first hydraulic generator 12 that is closer to the branching point with the first branch hydraulic passage 54. The switching valve 56 in this embodiment is a solenoid valve which is a three-way valve with two positions and three ports. Each port of the switching valve 56 is connected to the first hydraulic pressure generator 12 side of the first main hydraulic pressure passage 51, to the first wheel brake B1 side of the first main hydraulic pressure passage 51, and to the connecting hydraulic pressure passage 71, which will be described later. Furthermore, the second main hydraulic passage 52 is connected to the first main hydraulic passage 51 on the first wheel brake B1 side of the switching valve 56.

[0028] When energized, the switching valve 56, as shown in Figure 2, connects the first hydraulic pressure generator 12 side of the first main hydraulic pressure passage 51 to the first wheel brake B1 side, while the first main hydraulic pressure passage 51 and the connecting hydraulic pressure passage 71 are not connected. In a normally operating brake system 1, the switching valve 56 is energized when performing normal brake control and anti-lock brake control. When the switching valve 56 is not energized, as shown in Figure 1, the first main hydraulic passage 51 does not connect to the first hydraulic generator 12 side and the first wheel brake B1 side, while the first main hydraulic passage 51 and the connecting hydraulic passage 71 are in communication. In addition to when the power supply to the brake system 1 is turned OFF, the power supply to the switching valve 56 is stopped if the first hydraulic generator 12 or the first electronic control unit 14 is not operating normally.

[0029] In the first main hydraulic passage 51, a first inlet valve 51a is provided between the branching point of the second main hydraulic passage 52 and the branching point of the first branch hydraulic passage 54. The first inlet valve 51a is a normally open type solenoid valve that opens and closes the first main hydraulic passage 51. The first branch liquid passage 54 is equipped with a first outlet valve 54a. The first outlet valve 54a is a normally closed solenoid valve that opens and closes the first branch liquid passage 54.

[0030] In the second main hydraulic passage 52, a second inlet valve 52a is provided on the side of the first hydraulic generator 12 that is closer to the branching point with the second branch hydraulic passage 55. The second inlet valve 52a is a normally open type solenoid valve that opens and closes the second main hydraulic passage 52. The second branch liquid passage 55 is equipped with a second outlet valve 55a. The second outlet valve 55a is a normally closed solenoid valve that opens and closes the second branch liquid passage 55.

[0031] The first electronic control unit 14 has a housing that contains a control board and is attached to the first base unit 11. Based on information obtained from various sensors such as pressure sensors and stroke sensors, and pre-stored programs, the first electronic control unit 14 controls the operation of the first hydraulic pressure generator 12 and the opening and closing of each valve in the first brake system 50.

[0032] The first brake unit 10 is capable of performing anti-lock brake control. While anti-lock brake control is being performed, the switching valve 56 is energized, and the first hydraulic pressure generator 12 side of the first main hydraulic pressure passage 51 is in communication with the first wheel brake B1 side. During normal brake operation and when the pressure is increased in anti-lock brake control, as shown in Figure 2, the first inlet valve 51a and the second inlet valve 52a are open, while the first outlet valve 54a and the second outlet valve 55a are closed. As a result, the brake fluid pressure generated by the first hydraulic pressure generator 12 is transmitted to the two wheel brakes B1 and B2. During pressure reduction in anti-lock brake control, the first inlet valve 51a and the second inlet valve 52a are energized and closed, while the first outlet valve 54a and the second outlet valve 55a are energized and opened. As a result, brake fluid is released from the two wheel brakes B1 and B2 into the first return fluid passage 53, and the brake fluid pressure transmitted to the two wheel brakes B1 and B2 is reduced. During the holding phase of the anti-lock brake control, the first inlet valve 51a and the second inlet valve 52a are energized and closed, while the first outlet valve 54a and the second outlet valve 55a are also closed. This maintains the brake fluid pressure transmitted to the two wheel brakes B1 and B2.

[0033] The second brake unit 20 has the same configuration as the first brake unit 10 described above, and includes a second base 21, a second hydraulic pressure generator 22, a second brake system 60, a second reservoir tank 23, and a second electronic control unit 24. The second hydraulic pressure generator 22 generates brake fluid pressure corresponding to the stroke amount of the brake pedal P by moving the piston 22b inside the cylinder 22c using an electric motor 22a.

[0034] The second brake system 60 includes a third main hydraulic passage 61 leading from the second hydraulic pressure generator 22 to the third wheel brake B3, and a fourth main hydraulic passage 62 leading from the third main hydraulic passage 61 to the fourth wheel brake B4. The second brake system 60 is not equipped with a switching valve. Furthermore, the second brake system 60 has a second return fluid passage 63 that leads from the third main hydraulic passage 61 and the fourth main hydraulic passage 62 to the second reservoir tank 23. The second return fluid passage 63 comprises a third branch fluid passage 64 branching off from the third main hydraulic passage 61 and a fourth branch fluid passage 65 branching off from the fourth main hydraulic passage 62. The third branch fluid passage 64 and the fourth branch fluid passage 65 merge to form a single fluid passage. In other words, the second return fluid passage 63 comprises the third branch fluid passage 64 and the fourth branch fluid passage 65, which communicate with the third main hydraulic passage 61 and the fourth main hydraulic passage 62, respectively, and a fluid passage leading from the confluence point of the third branch fluid passage 64 and the fourth branch fluid passage 65 to the second reservoir tank 23.

[0035] The third main hydraulic passage 61 is equipped with a third inlet valve 61a, and the third branch hydraulic passage 64 of the second return hydraulic passage 63 is equipped with a third outlet valve 64a. In addition, the fourth main hydraulic passage 62 is equipped with a fourth inlet valve 62a, and the fourth branch hydraulic passage 65 is equipped with a fourth outlet valve 65a. Similar to the first brake unit 10, the second brake unit 20 is capable of performing antilock brake control by having the second electronic control device 24 control the operation of the second hydraulic pressure generator 22 and the opening and closing of each valve in the second brake system 60.

[0036] The brake system 1 of this embodiment includes a connecting hydraulic passage 71 that extends from the first main hydraulic passage 51 to the third main hydraulic passage 61. The connecting hydraulic passage 71 is composed of flow paths within the first base 11 and the second base 21, and piping provided between the first base 11 and the second base 21. One end of the connecting hydraulic passage 71 is connected to the switching valve 56. The other end of the connecting hydraulic passage 71 is in communication with the third main hydraulic passage 61, on the second hydraulic generator 22 side of the third inlet valve 61a.

[0037] In the brake system 1 of this embodiment, the drive amount of the second hydraulic pressure generator 22 is set to be greater when the switching valve 56 is de-energized than when the switching valve 56 is energized (see Figure 4). Specifically, the drive amount of the second hydraulic pressure generator 22 is controlled so that the amount of fluid required (necessary fluid amount) supplied from the second hydraulic pressure generator 22 is equal to the amount of brake fluid applied to each of the two wheel brakes (required brake fluid pressure) when the switching valve 56 is energized and the amount of brake fluid applied to each of the four wheel brakes (required brake fluid pressure) when the switching valve 56 is de-energized.

[0038] Next, the brake control in the brake system 1 of this embodiment will be described. During normal brake operation, the switching valve 56 of the first brake unit 10 is energized, as shown in Figure 2. As a result, the first hydraulic pressure generator 12 side and the first wheel brake B1 side of the first main hydraulic pressure passage 51 are connected. The brake fluid pressure generated by the first hydraulic pressure generator 12 is then transmitted to the first wheel brake B1 and also to the second wheel brake B2 through the second main hydraulic pressure passage 52. Furthermore, the brake fluid pressure generated by the second hydraulic pressure generator 22 is transmitted to the third wheel brake B3 via the third main hydraulic pressure passage 61, and also to the fourth wheel brake B4 via the fourth main hydraulic pressure passage 62. Thus, during normal braking, the first hydraulic pressure generator 12 generates braking force on the two front wheel brakes B1 and B2 on the FR and FL sides, and the second hydraulic pressure generator 22 generates braking force on the two rear wheel brakes B3 and B4 on the RR and RL sides.

[0039] During normal brake operation, as shown in Figure 3, a malfunction may occur in the first brake unit 10, causing at least one of the first electronic control unit 14 and the first hydraulic pressure generator 12 to fail to operate, and the switching valve 56 to become de-energized. In this case, the switching valve 56 returns to its initial state (de-energized state), resulting in a state where the first main hydraulic pressure passage 51 is not connected to the first hydraulic pressure generator 12 side and the first wheel brake B1 side, while the first main hydraulic pressure passage 51 is connected to the connecting hydraulic pressure passage 71. In this state, the brake fluid pressure generated by the second hydraulic pressure generator 22 is transmitted to the two wheel brakes B3 and B4 on the rear wheels RR and RL. Furthermore, the brake fluid pressure generated by the second hydraulic pressure generator 22 is also transmitted to the two wheel brakes B1 and B2 on the front wheels FR and FL through the third main hydraulic pressure passage 61, the connecting hydraulic pressure passage 71, the switching valve 56, the first main hydraulic pressure passage 51, and the second main hydraulic pressure passage 52. Thus, even when the first electronic control device 14 and the first hydraulic pressure generator 12 of the first brake unit 10 are not operating, the second hydraulic pressure generator 22 of the second brake unit 20 generates braking force on the two wheel brakes B1 and B2 on the front wheels FR and FL sides and the two wheel brakes B3 and B4 on the rear wheels RR and RL sides.

[0040] Furthermore, the drive amount of the second hydraulic pressure generator 22 is greater when the switching valve 56 is de-energized (when the first electronic control unit 14 and the first hydraulic pressure generator 12 are not operating) than when the switching valve 56 is energized (during normal brake operation) (see Figure 4). As a result, even when the second hydraulic pressure generator 22 applies brake fluid pressure to all four wheel brakes, the same brake fluid pressure as under normal conditions is applied to each wheel brake.

[0041] In the brake system 1 described above, during normal braking, as shown in Figure 2, the first hydraulic pressure generator 12 applies brake fluid pressure to the first wheel brake B1 and the second wheel brake B2, and the second hydraulic pressure generator 22 applies brake fluid pressure to the third wheel brake B3 and the fourth wheel brake B4. In this way, the brake system 1 allows for independent control of both brake units 10 and 20.

[0042] In the brake system 1 of this embodiment, as shown in Figure 3, even if the first electronic control device 14 or the first hydraulic pressure generator 12 of the first brake unit 10 are not operating, brake fluid pressure can be applied not only to the two wheel brakes B3 and B4 on the rear wheel RR and RL sides, but also to the two wheel brakes B1 and B2 on the front wheel FR and FL sides that are connected to the first brake unit 10. As a result, even if the first electronic control device 14 or the first hydraulic pressure generator 12 of the first brake unit 10 are not operating, a large braking force is generated in the wheel brakes B1 and B2 provided on the left and right front wheels FR and FL, allowing the vehicle to be braked while maintaining stability.

[0043] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from its spirit. For example, as shown in Figure 5, the third inlet valve 61a and the fourth inlet valve 62a may be configured to close when the first electronic control device 14 and the first hydraulic pressure generator 12 of the first brake unit 10 are not operating and the switching valve 56 is not energized. In this configuration, the brake fluid pressure generated by the second hydraulic pressure generator 22 is not transmitted to the third main hydraulic pressure passage 61, but is entirely transmitted to the first main hydraulic pressure passage 51. This allows for a significant increase in the braking force of the two front wheel brakes B1 and B2 on the front wheel FR and FL sides. In the aforementioned brake control, the first electric brake EB1 is activated to brake the left rear wheel RL, and the second electric brake EB2 is activated to brake the right rear wheel RR.

[0044] In the brake system 1 of this embodiment, the second electronic control device 24 shown in Figure 1 may be configured to detect the operating state of the first brake unit 10, and to switch between energized and de-energized states of the switching valve 56. In this configuration, the switching valve 56 is not de-energized during normal brake operation. However, if the second electronic control unit 24 detects a malfunction in the operation of the first brake unit 10, the second electronic control unit 24 de-energizes the switching valve 56, thereby allowing brake fluid pressure to be supplied from the second hydraulic pressure generator 22 to the two wheel brakes B1 and B2 of the first brake unit 10.

[0045] In the brake system 1 of this embodiment, the switching valve 56 is configured as a three-way valve, but a single switching valve may be configured by combining multiple solenoid valves.

[0046] In this embodiment, the first wheel brake B1 brakes the front wheel FL, the second wheel brake B2 brakes the front wheel FR, the third wheel brake B3 brakes the rear wheel RL, and the fourth wheel brake B4 brakes the rear wheel RR. However, the wheels that each wheel brake applies to are not limited. [Explanation of symbols]

[0047] 1. Brake System 10 First Brake Unit 11 First base 12. First hydraulic pressure generator 12a electric motor 12b Piston 12c cylinder 13. First reservoir tank 14 First Electronic Control Unit 20 Second brake unit 21 Second base 22 Second hydraulic pressure generator 22a Electric motor 22b Piston 22c cal 23 Second reservoir tank 24 Second Electronic Control Unit 50 First Brake System 51 First Main Hydraulic Circuit 51a First inlet valve 52 Second Main Hydraulic Circuit 52a Second inlet valve 53 First return fluid channel 54 First branch liquid channel 54a First outlet valve 55 Second branch liquid channel 55a Second outlet valve 56 Switching valve 60 Second braking system 61 Third Main Hydraulic Circuit 61a Third inlet valve 62 Fourth Main Hydraulic Circuit 62a Fourth inlet valve 63 Second return fluid channel 64 Third branch liquid channel 64a Third outlet valve 65 Fourth branch liquid channel 65a Fourth outlet valve 71 Connecting hydraulic circuit B1 First Wheel Brake B2 Second Wheel Brake B3 Third Wheel Brake B4 Fourth Wheel Brake EB1 First Electric Brake EB2 Second electric brake FL left front wheel FR Right front wheel RL (Left rear wheel) RR Right rear wheel P Brake pedal

Claims

1. A brake system comprising a first brake unit, a second brake unit, and a connecting hydraulic pressure passage connecting the first brake unit and the second brake unit, The aforementioned first brake unit is A first hydraulic pressure generator that generates brake fluid pressure according to the amount of operation of the brake lever, First braking system, The system includes the first hydraulic pressure generator and the first electronic control unit that controls the first brake system, The aforementioned first brake system is The first main hydraulic circuit extends from the first hydraulic pressure generator to the first wheel brake, The second main hydraulic passage extends from the first main hydraulic passage to the second wheel brake, The first main hydraulic passage includes a switching valve, The second main hydraulic passage is connected to the first main hydraulic passage on the first wheel brake side of the switching valve, The aforementioned second brake unit is A second hydraulic pressure generator that generates brake fluid pressure according to the amount of operation of the brake lever, Second braking system and The system includes the second hydraulic pressure generator and the second electronic control unit that controls the second brake system, The aforementioned second braking system is The third main hydraulic circuit extends from the second hydraulic pressure generator to the third wheel brake, The system includes a fourth main hydraulic passage extending from the third main hydraulic passage to the fourth wheel brake, The aforementioned connecting hydraulic passage extends from the first main hydraulic passage to the third main hydraulic passage. When energized, the switching valve is in a state where the first main hydraulic pressure passage is in communication with the first hydraulic pressure generator side and the first wheel brake side, and the first main hydraulic pressure passage is not in communication with the connecting hydraulic pressure passage. A brake system characterized in that, when the switching valve is not energized, the first main hydraulic pressure passage does not communicate with the first hydraulic pressure generator side and the first wheel brake side, and the first main hydraulic pressure passage communicates with the connecting hydraulic pressure passage.

2. A brake system according to claim 1, The first wheel brake and the second wheel brake are provided on the left and right front wheels, respectively. A braking system characterized in that the third wheel brake and the fourth wheel brake are provided on the left and right rear wheels, respectively.

3. A brake system according to claim 1, The aforementioned first brake system is A first inlet valve that opens and closes the first main hydraulic passage, A second inlet valve that opens and closes the second main hydraulic passage, The first main hydraulic passage and the second main hydraulic passage, and the return passage leading to the reservoir tank, A brake system characterized by comprising an outlet valve for opening and closing the return fluid passage.

4. A brake system according to claim 1, The drive amount of the second hydraulic pressure generator is, A brake system characterized in that the value is set such that the value is greater when the switching valve is not energized than when the switching valve is energized.

5. A brake system according to claim 4, The brake system is characterized in that the second hydraulic pressure generating device is set to increase the drive amount based on the required amount of fluid when the switching valve is not energized.

6. A brake system according to claim 2, The first rear wheel is equipped with the third wheel brake and the first electric brake. The second rear wheel is equipped with the aforementioned fourth wheel brake and second electric brake. The aforementioned second braking system is A third inlet valve that opens and closes the third main hydraulic passage, The system includes a fourth inlet valve that opens and closes the fourth main hydraulic passage, When the aforementioned switching valve is not energized, Close the third inlet valve and the fourth inlet valve, A braking system characterized by activating the first electric brake and the second electric brake.

7. A brake system according to claim 1, The brake system is characterized in that the switching valve is composed of a three-way valve.

8. A brake system according to claim 1, The first hydraulic pressure generating device and the second hydraulic pressure generating device are configured to generate brake fluid pressure by moving a piston within a cylinder using an electric motor. The first main hydraulic passage is connected to the cylinder of the first hydraulic pressure generating device. A brake system characterized in that the third main hydraulic passage is connected to the cylinder of the second hydraulic pressure generating device.

9. A brake system according to claim 1, The brake system is characterized in that the second electronic control device can switch between energized and de-energized states of the switching valve.

10. A brake system according to claim 9, The brake system is characterized in that the second electronic control unit switches between energized and de-energized states of the switching valve based on the detection of operation of the first brake unit.

Images