WO2018168307A1

WO2018168307A1 - Hydraulic control device, brake system, and auxiliary hydraulic unit for use in event of failure

Info

Publication number: WO2018168307A1
Application number: PCT/JP2018/005165
Authority: WO
Inventors: 亮平丸尾; 千春中澤; 旭渡辺; 大澤　俊哉
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2017-03-14
Filing date: 2018-02-15
Publication date: 2018-09-20
Also published as: JP2018149936A; JP6838263B2; DE112018001352T5

Abstract

Provided is a hydraulic control device capable of suppressing complication. This hydraulic control device comprises: a connection fluid path which connects a master cylinder and a wheel cylinder portion; a shutoff valve disposed in the connection fluid path; a first hydraulic source capable of supplying a brake fluid to a portion of the connection fluid path located to the side of the wheel cylinder portion with respect to the shutoff valve; a control unit capable of executing boost control to control the first hydraulic source and the shutoff valve and supply the brake fluid to the wheel cylinder portion when a brake pedal is operated; an opening-closing valve which is disposed in the connection fluid path and operates in the closing direction when the brake pedal is operated in a state in which the boost control is not in execution; and a second hydraulic source capable of supplying the brake fluid to a portion of the connection fluid path located to the side of the wheel cylinder portion with respect to the opening-closing valve, and capable of operating when the brake pedal is operated in a state in which the boost control is not in execution.

Description

Hydraulic pressure control device, brake system, and auxiliary hydraulic pressure unit for failure

The present invention relates to a hydraulic pressure control device.

Conventionally, there has been known a hydraulic pressure control device provided with a hydraulic pressure source capable of supplying brake fluid to the wheel cylinder side separately from the master cylinder. For example, the hydraulic pressure control device described in Patent Document 1 includes two hydraulic pressure sources as described above as countermeasures against failure.

US Patent Application Publication No. 2015/0175146

Since the conventional hydraulic pressure control device includes a control unit for each hydraulic pressure source, there is a risk of complication.

The hydraulic pressure control device according to an embodiment of the present invention includes a second hydraulic pressure source that can be activated when the brake pedal is operated in a state where the boost control by the first hydraulic pressure source is not activated.

Therefore, since complicated control is not required for the operation of the second hydraulic pressure source, complication can be suppressed.

The structure of the brake system of 1st Embodiment is shown. It is a perspective view of the master cylinder unit of a 1st embodiment. It is a perspective view of the 1st hydraulic unit of a 1st embodiment. It is the perspective view which looked at the 2nd hydraulic unit of a 1st embodiment from the 2nd motor side. It is the perspective view which looked at the 2nd hydraulic unit of a 1st embodiment from the side opposite to the 2nd motor. It is the perspective view which looked at the 2nd hydraulic pressure unit in the state where the cover of a 1st embodiment was removed from the 2nd motor side. It is the perspective view which saw through the inside of the 2nd hydraulic unit of a 1st embodiment from the 2nd motor side. The structure of the control system of the 2nd hydraulic pressure unit of 1st Embodiment is shown. It is a time chart which shows the operating state of a brake system at the time of failure of the boost control by the 1st hydraulic pressure unit of a 1st embodiment. It is a flowchart which shows the control logic of the 2nd hydraulic pressure unit of 2nd Embodiment. The structure of the brake system of 3rd Embodiment is shown. It is a time chart which shows the operating state of a brake system at the time of failure of the boost control by the 1st hydraulic pressure unit of a 3rd embodiment. The structure of the brake system of 4th Embodiment is shown. The structure of the liquid path in the 2nd hydraulic pressure unit of 5th Embodiment is shown. The structure of the brake system of 6th Embodiment is shown.

Hereinafter, modes for carrying out the present invention will be described with reference to the drawings.

[First embodiment]
First, the configuration will be described. The brake system 1 of the present embodiment is mounted on a vehicle, specifically an automobile. Automobiles include those having only an internal combustion engine (engine) as a prime mover for driving wheels, hybrid vehicles having an electric motor in addition to the engine, electric vehicles having only a motor, and the like. The vehicle has one or more wheels, specifically left and right front wheels FL and FR, and left and right rear wheels RL and RR as wheel portions. A wheel cylinder 102 is installed on each wheel. A brake operating unit is installed on each wheel FL to RR. The brake operation unit is, for example, a disk type, and includes a wheel cylinder 102 and a caliper. The caliper is operated by the hydraulic pressure (brake hydraulic pressure) of the wheel cylinder 102, and applies friction braking force to the wheels FL to RR according to the brake hydraulic pressure. These one or more wheel cylinders 102 function as a wheel cylinder part. The hydraulic circuit of the brake system 1 is divided into two systems, a primary system (P system) and a secondary system (S system). Hereinafter, when it is clearly indicated that the member or configuration relates to the P system, P is added to the end of the reference numeral, and when it is specified that the member or configuration is related to the S system, S is added to the end of the reference numeral. As shown in FIG. 1, the brake system 1 includes a first hydraulic unit 1A, a second hydraulic unit 1B, and a master cylinder unit 1C. Hereinafter, when it is clearly stated that the member or configuration relates to the first hydraulic unit 1A, an A is added to the end of the symbol, and when it is explicitly shown that the member or configuration is related to the second hydraulic unit 1B, the suffix B is attached to the end . The brake pedal 100 is a member (input member) that receives an input of a brake operation by a vehicle driver (driver). A push rod 101 is rotatably connected to the brake pedal 100. The push rod 101 is pushed in accordance with the depression operation of the brake pedal 100 and can move in the axial direction of the push rod 101. The push rod 101 has a flange 101f.

As shown in FIGS. 1 and 2, the master cylinder unit 1C has a reservoir tank 2 and a master cylinder 3. The reservoir tank 2 stores brake fluid and can replenish the master cylinder 3 and the

hydraulic units

1A and 1B with brake fluid. The bottom side of the reservoir tank 2 is partitioned by a partition wall 21 into a liquid chamber 23 for replenishing the master cylinder and a liquid chamber 24 for pump suction. The liquid chamber 23 is partitioned by a partition wall 22 into a P-system liquid chamber 23P and an S-system liquid chamber 23S. The partition wall 22 is lower than the partition wall 21. A liquid level sensor 26 is installed in the partition wall 22, and the liquid level height of the liquid chamber 23 can be measured. A replenishment port 25 is connected to the liquid chamber 24. A liquid level sensor 27 is installed in the liquid chamber 24, and the liquid level height of the liquid chamber 24 can be measured.

The master cylinder 3 includes a housing 30, a piston 31, a spring unit 32, and a seal member 33. Hereinafter, the x-axis is provided in the axial direction of the master cylinder 3, and the direction in which the push rod 101 is pushed in response to the depression operation of the brake pedal 100 is defined as the positive direction. As shown in FIG. 2, the housing 30 has a flange 306. The flange 306 is fixed to a vehicle-side member (such as a dash panel) by a bolt 307. Inside the housing 30, there are a cylinder 300, a supply port 301, and a supply port 302. The cylinder 300 is cylindrical and has two grooves 303 and 304 for each system. Each of the grooves 303 and 304 has an annular shape extending in the direction around the axis of the cylinder 300 (hereinafter referred to as the circumferential direction). The first groove 303 is on the x-axis positive direction side, and the second groove 304 is on the x-axis negative direction side. Each port 301, 302 is provided for each system. In each system, the supply port 301 opens to the cylinder 300 between the grooves 303 and 304 and opens to the outer surface of the housing 30. The replenishment port 301P is connected to the liquid chamber 23P of the reservoir tank 2, and the replenishment port 301S is connected to the liquid chamber 23S of the reservoir tank 2. The supply port 302 opens in the cylinder 300 on the x axis positive direction side with respect to the first groove 303 and also opens on the outer surface of the housing 30.

The master cylinder 3 is a tandem type, and the piston 31 is provided for each system. The piston 31 is installed inside the cylinder 300 and can reciprocate in the x-axis direction. The piston 31 is cylindrical and has two concave portions 311 and 312 separated by a partition wall 310. The first recess 311 is disposed on the x-axis positive direction side, and the second recess 312 is disposed on the x-axis negative direction side. A hole 313 passes through the peripheral wall of the first recess 311. There are a plurality of holes 313 in the circumferential direction. The piston 31P is installed on the x-axis negative direction side, and the piston 31S is installed on the x-axis positive direction side. The x-axis positive direction side of the push rod 101 is installed in the second recess 312P of the piston 31P. The x-axis positive direction end of the push rod 101 is in contact with the partition wall 310P. The cylinder 300 is divided into two

hydraulic pressure chambers

34P and 34S and an atmospheric pressure chamber 38 by both

pistons

31P and 31S. The hydraulic chamber 34P is located between the piston 31P and the piston 31S. The hydraulic chamber 34S is on the positive side of the piston 31S in the x-axis direction. Each

hydraulic chamber

34P, 34S is connected to a supply port 302. The atmospheric pressure chamber 38 is on the negative side in the x-axis direction of the hydraulic chamber 34P. A hole 305 that connects the atmospheric pressure chamber 38 and the outside is provided at the end of the housing 30 in the negative x-axis direction. The push rod 101 is installed through the hole 305. The seal member 33 is a rod seal U-packing or V-packing, and is installed in each of the grooves 303 and 304. The lip of the seal member 33 is in contact with the outer peripheral surface of the piston 31. The seal member 33 of the first groove 303 suppresses the flow of brake fluid from the hydraulic chamber 34 toward the replenishment port 301 on the outer peripheral side of the piston 31, and allows the flow in the opposite direction. The seal member 33 in the second groove 304P suppresses the flow of brake fluid from the supply port 301P toward the atmospheric pressure chamber 38 on the outer peripheral side of the piston 31P. The seal member 33 in the second groove 304S suppresses the flow of brake fluid from the hydraulic chamber 34P toward the replenishment port 301S on the outer peripheral side of the piston 31S.

The spring unit 32 includes a coil spring 320, a first retainer 321, a second retainer 322, and a stopper 323. Both retainers 321 and 322 have a bottomed cylindrical shape and have a bottom portion and a flange portion. One end of the stopper 323 has a bowl shape and is installed inside the first retainer 321 so as to be able to reciprocate. The other end of the stopper 323 is fixed to the bottom of the second retainer 322. The coil spring 320 surrounds both retainers 321 and 322. One end of the coil spring 320 is installed on the flange of the first retainer 321, and the other end of the coil spring 320 is installed on the flange of the second retainer 322. The coil spring 320 is always compressed. When the one end of the stopper 323 is engaged with the bottom of the first retainer 321, the extension of the coil spring 320 is restricted. The spring unit 32P is installed in the hydraulic chamber 34P. The flange of the first retainer 321P is installed on the partition wall 310S of the piston 31S, and the flange of the second retainer 322P is installed on the partition wall 310P of the piston 31P. The spring unit 32S is installed in the hydraulic chamber 34S. The flange of the first retainer 321S is installed on the inner wall of the cylinder 300 at the positive end in the x-axis direction, and the flange of the second retainer 322S is installed on the partition wall 310S of the piston 31S. In the initial state where the length of each

coil spring

320P, 320S is the maximum, both

pistons

31P, 31S are displaced maximum in the negative x-axis direction, and the flange portion 101f of the push rod 101 is located on the outer peripheral side of the hole 305 in the housing 30. Touch the inner wall. The inner wall restricts the movement of the flange portion 101f in the negative x-axis direction. In this initial state, the holes 313 of the

pistons

31P and 31S are located between the seal members 33 (lips) of the grooves 303 and 304 in the x-axis direction, and the first recesses 311 (hydraulic pressure chambers 34) of the

pistons

31P and 31S and The replenishment port 301 communicates through a hole 313.

The fixed portion 910 of the stroke sensor 91 is installed on the outer periphery of the housing 30 on the x-axis negative direction side. In the fixing unit 910, an element for detecting a change in magnetism is installed. A moving part 911 of the stroke sensor 91 is installed on the outer periphery of the piston 31P on the x-axis negative direction side. A permanent magnet 912 is installed in a part of the moving portion 911 in the circumferential direction. A rod 39 extending in the x-axis direction inside the atmospheric pressure chamber 38 is fixedly installed in the housing 30. The moving unit 911 can be displaced with respect to the rod 39 in the x-axis direction, and the displacement in the circumferential direction is restricted by the rod 39. Thereby, the permanent magnet 912 is more reliably opposed to the element of the fixed portion 910 in the circumferential direction.

The first hydraulic unit 1A is a main hydraulic unit that can increase the brake hydraulic pressure. The first hydraulic unit 1A can function as a booster unit for executing boost control. Further, the first hydraulic unit 1A can function as a hydraulic unit for executing side slip prevention control (ESC). Hereinafter, when it is clearly indicated that the member or configuration relates to the first hydraulic unit 1A, A is added to the end of the reference numeral. As shown in FIGS. 1 and 3, the first hydraulic unit 1A includes a first housing 40, a first pump unit 8A, a valve 7A, a stroke simulator 5, hydraulic pressure sensors 92 and 93, and an electronic control unit 90. . The first housing 40 is fixed to a vehicle-side member (such as the bottom of the engine compartment) via a bracket or an insulator. The first pump unit 8A has a first motor 80A and a first pump 81A as a first hydraulic pressure source. The first motor 80A is, for example, a DC motor, and an eccentric cam is attached to its drive shaft. The first pump 81A is a plunger pump. Five plungers are arranged radially around the drive shaft of the first motor 80A. When the first motor 80A rotates the eccentric cam, each plunger reciprocates. As a result, the first pump 81A sucks and discharges the brake fluid. The five plungers overlap in the direction (axial direction) in which the axis of the drive shaft of the first motor 80A extends. As a result, an increase in dimension of the first hydraulic unit 1A in the axial direction is suppressed.

Valve 7A has a solenoid valve and a check valve. The solenoid valve has a solenoid part and a valve part. The check valve can be formed in the valve portion by a member constituting the valve portion of the electromagnetic valve. The solenoid valve includes a shut-off valve 71A, a pressure increasing valve 72, a communication valve 73, a pressure regulating valve 74, a pressure reducing valve 75, a simulator out valve 77, and a simulator in valve 78. The shut-off valve 71A, the pressure increasing valve 72, and the pressure regulating valve 74 are normally open valves that open in a non-energized state and operate in the closing direction when energized, and are proportional control valves that can control the opening degree of the valve in accordance with the energization amount. It is. The pressure reducing valve 75, the communication valve 73, the simulator-out valve 77, and the simulator-in valve 78 are normally closed valves that close in a non-energized state and operate in the opening direction when energized. This is an on / off valve that can take two positions. The first pump unit 8A is arranged along one surface of the first housing 40 in the axial direction, and the valves are arranged along the other surface. Thereby, an increase in the size of the first hydraulic unit 1A is suppressed.

The first housing 40 is formed from an aluminum-based metal material. Inside the first housing 40 are a port, a fluid path, and a first reservoir 47. The port has a first input port 41, a first output port 42, a first suction port 43, a positive pressure port 44, a back pressure port 45, and a replenishment port 46. The liquid paths are the first connecting liquid path 11A, the first suction liquid path 12A, the first discharge liquid path 13A, the pressure adjusting liquid path 14, the discharge liquid path 15, the simulator positive pressure liquid path 16A, the simulator back pressure liquid path 17A, A simulator pressure increasing liquid path 18A and a simulator replenishing liquid path 19A are provided. Each port 41 to 46 opens on the outer surface of the first housing 40. The first reservoir 47 is connected to the first suction port 43. The first input port 41 is a port for inputting brake fluid to the first hydraulic unit 1A. The first output port 42 is a port for outputting brake fluid from the first hydraulic unit 1A.

One end of the first connection liquid path 11A is connected to the first input port 41. There is a shutoff valve 71A above the first connection liquid path 11A. In each system, the first connection liquid path 11A opposite to the first input port 41 with respect to the shutoff valve 71A branches into two. Each of the branch liquid passages 11a to 11d is connected to the first output port. A pressure increasing valve 72 is provided on the branch liquid passages 11a to 11d. The bypass liquid paths 111a to 111d are connected to the branch liquid paths 11a to 11d in parallel with the pressure increasing valve 72. There are check valves 720a to 720d in the bypass liquid passages 111a to 111d. The check valves 720a to 720d allow the flow of brake fluid from the first output port 42 side to the shutoff valve 71A side, and suppress the flow of brake fluid in the opposite direction. One end of the first suction fluid path 12A is connected to the first reservoir 47. The other end of the first suction fluid path 12A is connected to the suction part of the first pump 81A. One end of the first discharge liquid passage 13A is connected to the discharge portion of the first pump 81A. The other end side of the first discharge liquid passage 13A branches into two. Each of the branch liquid paths 13PA and 13SA is a first connection liquid path 11A and is connected between the pressure increasing valve 72 and the shutoff valve 71A. The branch liquid paths 13PA and 13SA function as a communication liquid path that connects the first connection liquid paths 11PA and 11SA of both systems. A communication valve 73 is provided above each of the branch liquid passages 13PA and 13SA. One end of the drainage passage 15 is connected to the first reservoir 47. The other end side of the discharge liquid passage 15 branches into four. The branch liquid paths 15a to 15d are branch liquid paths 11a to 11d of the first connection liquid path 11A, respectively, and are connected to the pressure increasing valve 72 on the first output port 42 side. A pressure reducing valve 75 is provided on the branch liquid passages 15a to 15d. One end of the pressure regulating fluid passage 14 is a first discharge fluid passage 13A and is connected to the communication valve 73 on the first pump 81A side. The other end of the pressure adjusting liquid passage 14 is connected to the discharge liquid passage 15. Above the pressure regulating fluid path 14 is a pressure regulating valve 74. The hydraulic pressure sensor 92 is connected to the first discharge liquid passage 13A between the first pump 81A and the communication valve 73, and detects the hydraulic pressure at this portion. In each system, the hydraulic pressure sensor 93 is connected to the first connecting liquid path 11A between the shutoff valve 71A and the pressure increasing valve 72, and detects the hydraulic pressure at this portion. The hydraulic pressure sensor 94 is a first connection fluid path 11PA, and is connected between the first input port 41P and the shut-off valve 71PA, and detects the hydraulic pressure at this portion.

One end of the simulator positive pressure fluid passage 16A is a first connection fluid passage 11PA and is connected between the first input port 41P and the shutoff valve 71PA. The other end of the simulator positive pressure fluid path 16A is connected to the positive pressure port 44. One end of the simulator back pressure liquid passage 17A is connected to the back pressure port 45. The other end of the simulator back pressure liquid path 17A is connected to the drain liquid path 15. A simulator out valve 77 is provided above the simulator back pressure liquid passage 17A. A bypass liquid path 170 is connected in parallel with the simulator out valve 77 to the simulator back pressure liquid path 17A. A bypass valve 170 has a check valve 770. The check valve 770 allows the flow of brake fluid from the first reservoir 47 side toward the back pressure port 45 side, and suppresses the flow of brake fluid in the opposite direction. One end of the simulator pressure increasing fluid passage 18A is a simulator back pressure fluid passage 17A and is connected between the back pressure port 45 and the simulator out valve 77. The other end of the simulator pressure increasing liquid path 18A is a first connection liquid path 11PA and is connected between the shutoff valve 71PA and the

pressure increasing valves

72a and 72d. A simulator-in valve 78 is provided above the simulator pressure increasing fluid passage 18A. A bypass liquid path 180 is connected to the simulator pressure increasing liquid path 18A in parallel with the simulator-in valve 78. A bypass valve 180 has a check valve 780. The check valve 780 allows the flow of brake fluid from the simulator back pressure fluid passage 17A (back pressure port 45) side to the first connection fluid passage 11PA side, and suppresses the flow of brake fluid in the opposite direction. One end of the simulator replenishment liquid path 19A is connected to the replenishment port 46. The other end of the simulator replenishment liquid path 19A is connected to the discharge liquid path 15.

The stroke simulator 5 includes a housing 50, a piston 51, a first spring unit 52, a second spring unit 53, and a seal member 54. The housing 50 is fixed to the first housing 40. Hereinafter, the y-axis is provided in the axial direction of the stroke simulator 5, and the direction in which the piston 51 moves in response to the inflow of the brake fluid into the positive pressure chamber 55 according to the depression operation of the brake pedal 100 is defined as the positive direction. In this embodiment, the y-axis extends in the vertical direction, and the lower side in the vertical direction is the positive y-axis direction. Inside the housing 50 are a cylinder 500, a positive pressure port 501, a back pressure port 502, and a replenishment port 503. The cylinder 500 has a stepped cylindrical shape, and has two

seal grooves

504 and 505 and one communication groove 506 on the small diameter side. Each of the grooves 504 to 506 has an annular shape extending in the direction around the axis of the cylinder 500 (hereinafter referred to as the circumferential direction). The first seal groove 504 is on the y-axis positive direction side, and the second seal groove 505 is on the y-axis negative direction side. The positive pressure port 501 opens to the small diameter portion of the cylinder 500 on the y axis negative direction side of the second seal groove 505 and opens to the outer surface of the housing 50 to connect to the positive pressure port 44 of the first housing 40. . The back pressure port 502 opens to the large diameter portion of the cylinder 500 on the positive side in the y-axis direction from the first seal groove 504, and opens to the outer surface of the housing 50 to connect to the back pressure port 45 of the first housing 40. To do. The supply port 503 opens to the cylinder 500 between the

seal grooves

504 and 505 and opens to the outer surface of the housing 50 to connect to the supply port 46 of the first housing 40. The communication groove 506 connects the supply port 503 and the first seal groove 504.

The piston 51 is installed inside the cylinder 500 (small diameter portion) and can reciprocate in the y-axis direction. The piston 51 is cylindrical and has two

concave portions

511 and 512 partitioned by a partition wall 510. The first recess 511 is disposed on the y-axis negative direction side, and the second recess 512 is disposed on the y-axis positive direction side. A hole 513 passes through the peripheral wall of the first recess 511. There are a plurality of holes 513 in the circumferential direction. A hole 514 passes through the peripheral wall of the second recess 512. There are a plurality of holes 514 in the circumferential direction. The second recess 512 has a protrusion 515 extending from the partition wall 510 in the positive y-axis direction. The cylinder 500 is divided into a positive pressure chamber 55 and a back pressure chamber 56 by the piston 51. The positive pressure chamber 55 is connected to the positive pressure port 501. The back pressure chamber 56 is connected to the back pressure port 502. The positive pressure chamber 55 is on the y axis negative direction side of the piston 51. The back pressure chamber 56 is on the positive side of the piston 51 in the y-axis direction. The housing 50 is provided with an air vent valve 58 for the positive pressure chamber 55 and an air vent valve 59 for the back pressure chamber 56. The valve 58 is at the y-axis negative direction end of the positive pressure chamber 55, and the valve 59 is at the y-axis negative direction end of the back pressure chamber 56. The opening on the positive side in the y-axis direction of the cylinder 500 is liquid-tightly closed by the lid member 57. The lid member 57 has a bottomed first recess 571. The first recess 571 has a protrusion 570 extending from the bottom in the negative y-axis direction. The protrusion 570 has a bottomed second recess 572. The seal member 54 is a U seal or a V seal for rod seal, and is installed in each

seal groove

504, 505. The lip of the seal member 54 is in contact with the outer peripheral surface of the piston 51. The seal member 54 of the first seal groove 504 suppresses the flow of brake fluid from the back pressure chamber 56 toward the replenishment port 503 on the outer peripheral side of the piston 51, and allows the flow in the opposite direction. The seal member 54 of the second seal groove 505 suppresses the flow of brake fluid from the positive pressure chamber 55 toward the supply port 503 on the outer peripheral side of the piston 51, and allows the flow in the opposite direction.

The first spring unit 52 includes a first coil spring 520, a first retainer 521, a second retainer 522, a stopper 523, and a first damper 524. The first damper 524 has a cylindrical shape and is an elastic member formed of rubber or the like. Other configurations of the first spring unit 52 are the same as those of the spring unit 32 of the master cylinder 3. The second spring unit 53 includes a second coil spring 530, a retainer 531, and a second damper 532. The retainer 531 has a bottomed cylindrical shape, and has a bottom portion and a flange portion. The coil diameter, wire diameter, and spring coefficient of the second coil spring 530 are each larger than that of the first coil spring 520. The second damper 532 is a columnar shape having a constriction, and is an elastic member formed of rubber or the like. Both spring units 52 and 53 are installed in the back pressure chamber 56. The first retainer 521 of the first spring unit 52 is fitted to the protrusion 515, and the flange portion is installed on the partition wall 510 of the piston 51. A first damper 524 is installed between the protrusion 515 and the stopper 523. The collar portion of the second retainer 522 is installed at the bottom of the retainer 531 of the second spring unit 53. The negative end of the second coil spring 530 in the y-axis direction is installed at the flange portion of the retainer 531. The positive end in the y-axis direction of the second coil spring 530 is fitted to the protrusion 570 of the lid member 57 and is installed at the bottom of the first recess 571. A second damper 532 is installed in the second recess 572 of the lid member 57. The second damper 532 protrudes in the negative y-axis direction from the protrusion 570 and faces the bottom of the retainer 531. In an initial state in which the lengths of the coil springs 520 and 530 are maximized, the piston 51 is maximally displaced in the y-axis negative direction side and contacts the inner wall of the cylinder 500 on the y-axis negative direction side. The movement of the piston 51 in the negative y-axis direction is restricted by the inner wall. In this initial state, the hole 513 of the piston 51 overlaps the positive pressure port 501 in the y-axis direction. The hole 514 is located between the seal member 54 (lip) of the first seal groove 504 and the supply port 503 in the y-axis direction, and the second recess 512 (back pressure chamber 56) of the piston 51 and the supply port 503 are formed in the hole 514. And it communicates through the communication groove 506.

The second hydraulic pressure unit 1B is an auxiliary hydraulic pressure unit that can increase the brake hydraulic pressure so as to supplement the first hydraulic pressure unit 1A. Hereinafter, when it is clearly indicated that the member or configuration relates to the second hydraulic unit 1B, B is appended to the end of the reference numeral. As shown in FIGS. 1 and 4 to 7, the second hydraulic pressure unit 1B includes a second housing 60, a second pump unit 8B, a valve 7B, a solenoid case 600, and a cover 601. The hydraulic circuit of the second hydraulic unit 1B is divided into two systems, a primary system (p system) and a secondary system (s system). In the following, when it is clearly stated that the member or configuration is related to the p system, p is added to the end of the symbol, and when it is clearly indicated that the material or structure is related to the s system, s is added to the end of the symbol. The second pump unit 8B has one second motor 80B and a second pump 81B as a second hydraulic pressure source. As shown in FIG. 7, the second motor 80B is fixed to the second housing 60 by a bolt 801. The second motor 80B is, for example, a DC motor, and an eccentric cam is attached to its drive shaft. The second pump 81B is a plunger pump. Two second pumps 81B are formed by arranging the two plungers so as to face each other around the drive shaft of the second motor 80B. Each plunger reciprocates as the second motor 80B rotationally drives the eccentric cam. As a result, the two second pumps 81B respectively suck and discharge the brake fluid. The valve 7B has a solenoid valve and a check valve. The electromagnetic valve has an on-off valve 71B. The on-off valve 71B is a normally open proportional control valve. The on-off valve 71B may be an on / off valve.

The second housing 60 is formed from an aluminum-based metal material. The second housing 60 is fixed to a vehicle-side member (such as the bottom of the engine compartment) via a bracket or an insulator. Inside the second housing 60 are a port, a fluid path, a second reservoir 64, and a bolt hole 65. A bolt for fixing the bracket or the insulator is inserted into the bolt hole 65. The port has a second input port 61, a second output port 62, and a second suction port 63. The liquid path includes a second connection liquid path 11B, a second suction liquid path 12B, and a second discharge liquid path 13B. Each port 61 to 63 opens to the outer surface of the second housing 60. The second reservoir 64 is connected to the second suction port 63. The second input port 61 is a port for inputting brake fluid to the second hydraulic pressure unit 1B. The second output port 62 is a port for outputting brake fluid from the second hydraulic unit 1B. One end of the second connection liquid path 11B is connected to the second input port 61, and the other end of the second connection liquid path 11B is connected to the second output port 62. An on-off valve 71B is above the second connection liquid path 11B. The bypass liquid path 110 is connected to the second connection liquid path 11B in parallel with the on-off valve 71B. A bypass valve 110 has a check valve 710. The check valve 710 allows the flow of brake fluid from the second input port 61 side to the second output port 62 side, and suppresses the flow of brake fluid in the opposite direction. One end of the second suction fluid path 12B is connected to the second reservoir 64. The other end of the second suction fluid path 12B is connected to the suction part of the second pump 81B. One end of the second discharge liquid passage 13B is connected to the discharge portion of the second pump 81B. The other end of the second discharge liquid path 13B is a second connection liquid path 11B and is connected between the on-off valve 71B and the second output port 62.

The solenoid case 600 is made of resin and is fixed to the second housing 60 by bolts 602. As shown in FIG. 6, in the case 600, the second motor 80B (a part thereof) and the solenoid of the on-off valve 71B are accommodated. The case 600 has a hole 603, and the second motor 80 passes through the hole 603. The cover 601 is attached to the case 600, covers the second motor 80B and the solenoid of the on-off valve 71B, and protects them from the outside (moisture or the like).

The master cylinder piping 10M connects the master cylinder 3 and the first hydraulic unit 1A. One end of the master cylinder pipe 10M is connected to the supply port 302 of the master cylinder 3, and the other end of the master cylinder pipe 10M is connected to the first input port 41 of the first hydraulic unit 1A. The relay pipe 10I connects the first hydraulic unit 1A and the second hydraulic unit 1B. One end of the relay pipes 10Ip and 10Is is connected to the

first output ports

42a and 42b of the first hydraulic unit 1A, respectively, and the other end of the relay pipes 10Ip and 10Is is the second input port 61p of the second hydraulic unit 1B, respectively. Connect to 61s. The front wheel cylinder pipes 10Wa and 10Wb connect the second hydraulic unit 1B and the

wheel cylinders

102a and 102b of the front wheels FL and FR. One end of the front wheel cylinder pipes 10Wa and 10Wb is connected to the

second output ports

62p and 62s of the second hydraulic unit 1B, respectively, and the other end of the front wheel cylinder pipes 10Wa and 10Wb is connected to the

front wheel cylinders

102a and 102b, respectively. . The rear wheel wheel cylinder pipes 10Wc and 10Wd connect the first hydraulic unit 1A and the

wheel cylinders

102c and 102d of the rear wheels RL and RR. One end of each of the rear wheel wheel cylinder pipes 10Wc and 10Wd is connected to the

first output port

42c and 42d of the first hydraulic unit 1A, and the other end of the rear wheel wheel cylinder pipes 10Wc and 10W is respectively connected to the rear

wheel wheel cylinders

102c and 102d. Connect to. The reservoir pipe 10R connects the reservoir tank 2 and the

hydraulic units

1A and 1B. One end of the reservoir pipe 10R is connected to the supply port 25 of the reservoir tank 2. The other end of the reservoir pipe 10R branches into two. The branch pipe 10RA is connected to the first suction port 43 of the first hydraulic unit 1A. The branch pipe 10RB is connected to the second suction port 63 of the second hydraulic unit 1B. In addition, a partition is provided in the liquid chamber 24 of the reservoir tank 2 to partition the two liquid chambers 24A and 24B, and the replenishment ports 25A and 25B that open to the respective liquid chambers 24A and 24B and the suctions of the respective

hydraulic units

1A and 1B The

ports

43 and 63 may be connected by separate reservoir pipes 10RA and 10RB, respectively.

The internal liquid passages of the pipes 10M, 10I, and 10W and the connection liquid passages 11A and 11B of the

hydraulic units

1A and 1B function as the connection liquid passage 11 that connects the master cylinder 3 and the wheel cylinder 102. A connection liquid path 11 is connected to the supply port 302 of the master cylinder 3. The connecting liquid path 11P branches into a liquid path 11a connected to the wheel cylinder 102a of the front left wheel FL and a liquid path 11d connected to the wheel cylinder 102d of the rear right wheel RR. The connection liquid path 11S branches into a liquid path 11b connected to the wheel cylinder 102b of the front right wheel FR and a liquid path 11c connected to the wheel cylinder 102c of the rear left wheel RL. The on-off valve 71B is in the connection liquid path 11 on the wheel cylinder 102 side with respect to the shutoff valve 71A.

The master cylinder 3 operates according to the operation of the brake pedal 100 and generates hydraulic pressure. When the brake pedal 100 is depressed, thrust on the x-axis positive direction side acts on the piston 31P via the push rod 101. When the piston 31 slightly moves from the initial position to the x-axis positive direction side while pushing and shrinking the coil spring 320 and the hole 313 is displaced from the seal member 33 (lip) of the first groove 303 to the x-axis positive direction side, the replenishment port Communication between 301 and the hydraulic chamber 34 is blocked. When the piston 31 further strokes in the positive x-axis direction in this state, the volume of the hydraulic chamber 34 is reduced, so that hydraulic pressure (master cylinder hydraulic pressure) is generated in the hydraulic chamber 34 and the supply port 302 Brake fluid is about to flow out.

The stroke simulator 5 operates in response to the operation of the brake pedal 100, and can generate an appropriate operation reaction force of the brake pedal 100. When brake fluid flowing out from the master cylinder 3 in response to the brake operation flows into the positive pressure chamber 55 via the simulator positive pressure fluid passage 16A, hydraulic pressure is generated in the positive pressure chamber 55, and the pistons are compressed while compressing the coil springs 520 and 530. Moves to the positive side of the y-axis. Brake fluid flows out from the back pressure chamber 56 and is discharged to the first reservoir 47 through the simulator back pressure fluid passage 17A (simulator out valve 77). As a result, a pedal stroke is generated and a pedal reaction force is generated by the biasing force of the coil springs 520 and 530. When the first coil spring 520 is compressed by a predetermined amount or more according to the stroke of the piston 51, the first damper 524 and the stopper 523 come into contact with each other, and the first damper 524 is compressed and elastically deformed together with the first coil spring 520. When the piston 51 further strokes, the second coil spring 530 starts compressive deformation. When the second coil spring 530 is compressed by a predetermined amount or more, the second damper 532 and the retainer 531 come into contact with each other, and the second damper 532 is compressed and elastically deformed together with the second coil spring 530. In this way, the coil springs 520 and 530 having different spring coefficients are connected in series, and these are elastically deformed step by step in order, whereby the characteristics of both coil springs as a whole (the change of the spring coefficient with respect to the deformation amount). Characteristic) becomes nonlinear. Thereby, the pedal reaction force generated by the stroke simulator 5 in accordance with the operation of the piston 51 (pedal stroke) can be made closer to a more desirable characteristic. Further, the above characteristics are smoothed by the elastic deformation of the

dampers

524 and 532. Thereby, pedal feeling can be improved.

The first pump 81A can discharge the brake fluid to the first output port 42 side (the connection fluid passage 11 on the wheel cylinder 102 side with respect to the shut-off valve 71A) from the shut-off valve 71A of the first connection fluid passage 11A. Yes, brake fluid can be supplied to the wheel cylinder 102. The first pump 81A sucks the brake fluid in the first reservoir 47 through the first suction liquid path 12A and discharges it to the first discharge liquid path 13A (liquid paths 13PA, 13SA). The brake fluid is supplied to the first reservoir 47 from the reservoir tank 2 through the pipe 10RA. The brake fluid boosted by the first pump 81A is supplied to the first connection fluid passage 11A, and then the relay pipe 10I, the second hydraulic pressure unit 1B (second connection fluid passage 11B), and the front wheel wheel cylinder piping 10Wa, It is supplied to the

front wheel cylinders

102a and 102b via 10Wb and supplied to the

rear wheel cylinders

102c and 102d via the rear wheel cylinder cylinders 10Wc and 10Wd. The second pump 81B can discharge the brake fluid to the second output port 62 side (the connection liquid path 11 on the wheel cylinder 102 side with respect to the on-off valve 71B) from the on-off valve 71B of the second connection liquid path 11B. Yes, brake fluid can be supplied to the wheel cylinder 102. The second pump 81B can supply the brake fluid only to the

connection fluid passages

11a and 11b connected to the

wheel cylinders

102a and 102b corresponding to the front wheels FL and FR among all the wheels. The second pump 81B sucks the brake fluid in the second reservoir 64 through the second suction fluid passage 12B and discharges it to the second discharge fluid passage 13B. The brake fluid is supplied to the second reservoir 64 from the reservoir tank 2 via the pipe 10RB. The brake fluid boosted by the second pump 81B is supplied to the second connection fluid passage 11B and then supplied to the

front wheel cylinders

102a and 102b via the front wheel cylinder pipes 10Wa and 10Wb.

The

reservoirs

47 and 64 of the

hydraulic units

1A and 1B can continuously supply brake fluid to the pump 8 even when there is a fluid leak from the reservoir pipe 10R, for example. In the

hydraulic units

1A and 1B, when the

hydraulic units

1A and 1B are arranged so that the

reservoirs

47 and 64 are positioned on the upper side in the vertical direction, the functions of the

reservoirs

47 and 64 can be more reliably exhibited.

An electronic control unit (hereinafter, ECU) 90 is installed on one side of the first housing 40 of the first hydraulic unit 1A. The ECU 90 is electrically connected to the first motor 80A of the first hydraulic pressure unit 1A, the solenoids of the electromagnetic valves 7A, and the

hydraulic pressure sensors

92, 93, 94. The ECU 90 is electrically connected to the stroke sensor 91, the

liquid level sensors

26 and 27, and the second motor 80B and the on-off valve 71B (solenoid thereof) of the second hydraulic pressure unit 1B via a harness. The ECU 90 is connected to other control devices on the vehicle side via an in-vehicle network such as CAN. The ECU 90 includes a first control unit 901, a second control unit 902, and a failure notification unit 903. The first control unit 901, based on the detection value of the sensor 91 and the like, information on the running state input from the vehicle side, and a built-in program (stored in the ROM), the electromagnetic valve 7A of the first hydraulic unit 1A. And the rotation speed of the first motor 80A (that is, the discharge amount of the first pump 81A) is controlled. Thereby, the wheel cylinder hydraulic pressure (hydraulic braking force) of each wheel FL to RR is controlled. The first controller 901 can execute various types of brake control by controlling the wheel cylinder hydraulic pressure. Brake control includes boost control to reduce driver's braking force, anti-lock brake control (ABS) to suppress wheel slip due to braking, traction control to suppress wheel drive slip, vehicle Brake control for motion control, automatic brake control such as preceding vehicle follow-up control, regenerative cooperative brake control, and the like. Vehicle motion control includes vehicle behavior stabilization control such as skidding prevention.

The first control unit 901 is a control device inside the microcomputer, and functions as a fluid pressure control device together with the sensor 91 and the like and the actuator (the electromagnetic valve 7A and the first motor 80A) of the first fluid pressure unit 1A. The first control unit 901 includes an input unit 904, a calculation unit 905, and an output unit 906. The input unit 904 reads information detected by the sensor 91 and the like and information from the in-vehicle network through an input interface circuit inside the microcomputer. Based on the information read by the input unit 904, the arithmetic unit 905 performs arithmetic processing for generating an actuator drive pattern in accordance with an embedded program (control algorithm). For example, the calculation unit 905 detects a displacement amount (pedal stroke) of the brake pedal 100 as a brake operation amount based on a detection value of the stroke sensor 91. During boost control, based on the detected pedal stroke, a desired boost ratio, that is, the ideal relationship between the pedal stroke and the driver's required brake fluid pressure (vehicle deceleration required by the driver) is achieved. Set the target wheel cylinder hydraulic pressure. During regenerative cooperative brake control, for example, the sum of the regenerative braking force input from the control unit of the regenerative braking device of the vehicle and the hydraulic braking force corresponding to the target wheel cylinder hydraulic pressure satisfies the vehicle deceleration required by the driver. The target wheel cylinder hydraulic pressure is calculated. At the time of motion control, for example, based on the detected vehicle motion state quantity (wheel speed, yaw rate, longitudinal acceleration, lateral acceleration, etc.), the target wheel cylinder fluid of each wheel FL to RR that realizes a desired vehicle motion state Calculate the pressure. The calculation unit 905 calculates a command for driving the actuator so as to realize the target wheel cylinder hydraulic pressure, and outputs the command to the output unit 906. The drive command may relate to a current value, or may relate to a torque or a displacement amount. The output unit 906 converts the drive command value from the calculation unit 905 and outputs it to the actuator drive circuit through an output interface circuit inside the microcomputer. The output unit 906 includes a PWM duty value calculation unit and the like. The output interface circuit includes a square wave generation circuit that generates a PWM signal, an inverter, and the like. Note that the input unit 904 and the output unit 906 may be realized by an electronic circuit (interface circuit). The calculation means not only mathematical calculation but also general processing on software. In the calculation unit 905, the target wheel cylinder hydraulic pressure that achieves a predetermined boost ratio may be set by calculation in addition to being set by a map in the microcomputer.

The first control unit 901 deactivates the first pump 81A and controls the shutoff valve 71A in the opening direction. In this state, the connecting fluid path 11 that connects the

hydraulic chambers

34P and 34S of the master cylinder 3 and the wheel cylinder 102 has the wheel cylinder hydraulic pressure generated by the master cylinder hydraulic pressure generated using the depression force of the brake pedal 100. Realize the tread force brake (non-boosting control) to be created. At the time of pedaling braking, the first control unit 901 controls the simulator-in valve 78 and the simulator-out valve 77 in the closing direction. As a result, the stroke simulator 5 is deactivated.

The first control unit 901 controls each actuator using the hydraulic pressure generated by the first pump 81A in a state where the communication between the master cylinder 3 and the wheel cylinder 102 is blocked by controlling the actuator of the first hydraulic unit 1A. The hydraulic pressure in the cylinder 102 can be individually controlled (independent of the brake operation by the driver). The first control unit 901 operates the first pump 81A and controls the shutoff valve 71A in the closing direction. In this state, the fluid passage (the first suction fluid passage 12A, the first discharge fluid passage 13A, etc.) connecting the first reservoir 47 and the wheel cylinder 102 is the foil cylinder generated by the fluid pressure generated using the first pump 81A. A so-called brake-by-wire system that creates hydraulic pressure is realized. During brake-by-wire, the first control unit 901 controls the simulator-in valve 78 in the closing direction and the simulator-out valve 77 in the opening direction. Thereby, the stroke simulator 5 operates. Note that if the power failure of the first hydraulic unit 1A occurs during the operation of the stroke simulator 5, the simulator out valve 77 is closed. Due to the force of the coil springs 520 and 530, the piston 51 strokes in the negative y-axis direction toward the initial position. When the hole 514 of the piston 51 returns to the y-axis positive direction side with respect to the seal member 54 (the lip) of the first seal groove 504, the back pressure chamber 56 and the supply port 503 communicate with each other. As a result, the brake fluid is smoothly supplied from the first reservoir 47 (reservoir tank 2) to the back pressure chamber 56 via the simulator supply liquid passage 19A.

In order to execute the boost control, the first control unit 901 operates the first pump 81A at a predetermined number of revolutions when operating the brake pedal 100, closes the shutoff valve 71A, and opens the pressure increasing valve 72. The communication valve 73A is controlled in the opening direction, and the pressure reducing valve 75 is controlled in the closing direction. The opening and closing of the pressure regulating valve 74 is controlled so that the fluid pressure in the first discharge fluid passage 13A, which is the fluid pressure upstream of the pressure regulating valve 74, becomes the target fluid pressure corresponding to the target wheel cylinder fluid pressure. As a result, the brake fluid pressure is supplied to the wheel cylinder 102 (the brake fluid is supplied to generate the fluid pressure), and the target wheel cylinder fluid pressure is realized. The upstream hydraulic pressure is obtained by using any one or a plurality of detected values (for example, average values) of the

hydraulic pressure sensors

92, 93P, 93S. In the boost control, a wheel cylinder hydraulic pressure higher than the master cylinder hydraulic pressure is created using the first pump 81A as a hydraulic pressure source instead of the engine negative pressure booster. Thus, the brake operation force is assisted by generating a hydraulic braking force that is insufficient with the driver's brake operation force.

It should be noted that the simulator out valve 77 may be controlled in the closing direction until the first pump 81A can generate a sufficiently high wheel cylinder hydraulic pressure after the start of the depression operation of the brake pedal 100. As a result, the brake fluid flowing out from the back pressure chamber 56 is supplied to the connecting fluid passage 11A through the simulator pressure-increasing fluid passage 18A (the bypass fluid passage 180 and the check valve 780), and is supplied toward the wheel cylinder 102. . Thereby, the pressure | voltage rise responsiveness of wheel cylinder hydraulic pressure can be improved. When the first pump 81A enters an operation state in which a sufficiently high wheel cylinder hydraulic pressure can be generated, the simulator out valve 77 is controlled in the opening direction so that the brake fluid is discharged from the back pressure chamber 56 to the first reservoir 47. Can be switched to. Note that the flow path cross-sectional area of the simulator pressure increasing liquid path 18A may be increased by controlling the simulator in valve 78 in the opening direction while the simulator out valve 77 is controlled in the closing direction.

The failure notification unit 903 generates a signal (normal signal) indicating that the boost control can be normally operated while the boost control by the first hydraulic pressure unit 1A is normally operable. Is continuously output to the signal line. The normal signal is, for example, a square wave having a predetermined duty ratio. If the boost control is not normally operable, the failure notification unit 903 does not generate a normal signal and does not output it to the signal line. The case where the boost control is not normally operable is a case where the ECU 90, the sensor 92, or the like, or the actuator of the first hydraulic unit 1A has failed (including power failure of the first hydraulic unit 1A). “The state in which the failure notifying unit 903 does not output a normal signal” corresponds to “notifying” the failure of the boost control (that the boost control is not normally operable) to other places.

The second control unit 902 functions as a hydraulic pressure control device together with the actuators (the on-off valve 71B and the second motor 80B) of the second hydraulic pressure unit 1B. The second control unit 902 can execute boost control by controlling the second pump 81B and the on-off valve 71B of the second hydraulic pressure unit 1B. As shown in FIG. 8, the second control unit 902 and the actuator drive circuit 907 of the second hydraulic unit 1B constitute a control system for the second hydraulic unit 1B. The second control unit 902 and the drive circuit 907 are circuits that are independent of the drive circuit of the actuator of the first control unit 901 and the first hydraulic unit 1A inside the ECU 90. The drive circuit 907 has a relay 908 on a power supply line 909 extending between a power supply (battery) and ground. The relay 908 is a semiconductor relay (for example, a power MOSFET). A mechanical relay may be used. On the power line 909, the coil of the second motor 80B and the solenoid of the on-off valve 71B are connected in parallel. The drive circuit 907 is a current drive circuit, and the relay 908 is between a coil or the like and ground. Note that the drive circuit 907 may be a voltage drive circuit. The second control unit 902 is connected to the relay 908 via a signal line. A failure notification unit 903 and a stroke sensor 91 are connected to the second control unit 902 via a signal line.

The second control unit 902 is an electric circuit that can generate a signal, and has a relay sequence, for example. The second control unit 902 generates a relay drive signal when there is no normal signal input from the failure notification unit 903 (for example, a predetermined time or more) and the detection value input from the stroke sensor 91 exceeds a predetermined value. This is output to the relay 908. The relay drive signal is a switching signal for switching the relay 908 from OFF to ON. The second control unit 902 does not generate a relay drive signal when a normal signal is input from the failure notification unit 903 or when the detection value input from the stroke sensor 91 is equal to or less than the predetermined value. It is possible to generate a relay drive signal in the absence of a normal signal input (in response to a signal input from the stroke sensor 91), the failure of the boost control by the first hydraulic unit 1A (the boost control described above) Is equivalent to “detect”. Here, the second control unit 902 functions as a failure detection unit. The second control unit 902 generates a relay drive signal, generates a signal (alert signal) for displaying an alert on the instrument panel or generating an alarm sound, and outputs the signal. Also good.

Next, the function and effect will be described. Based on FIG. 9, the operation of the brake system 1 when the boost control by the first hydraulic pressure unit 1A is not normally operable (not operating) will be described. In the example shown in FIG. 9, the brake pedal 100 is depressed from time t1 to t6, the depression amount is maintained from time t6 to t7, and the brake pedal 100 is depressed from time t7 to t8. After time t1, the pedal effort F increases from zero. Immediately before time t2, the pedaling force F reaches a predetermined initial pedaling force (for example, about 15N) [0] at which the brake pedal 100 starts to move. At time t2, the pedal stroke S (detected value of the stroke sensor 91) exceeds the predetermined value S0. In addition, the brake lamp switch is switched from OFF to ON. Since the boost control by the first hydraulic pressure unit 1A is not normally operable (the boost control is not activated), the failure notification unit 903 does not generate a normal signal, and the second control unit 902 is normal. There is no signal input. Therefore, when the detection value of the stroke sensor 91 input to the second control unit 902 exceeds the predetermined value S0 at time t2, the second control unit 902 generates a relay drive signal and outputs it to the relay 908. As a result, the relay 908 is switched from OFF to ON, and energization of the second motor 80B and the on-off valve 71B is started. The on-off valve 71B is closed and the second pump 81B is activated. The second control unit 902 does not particularly control the rotational speed of the second pump 81B. The brake fluid boosted by the second pump 81B is supplied to the

front wheel cylinders

102a and 102b. Therefore, after time t2, the hydraulic pressure in the

front wheel cylinders

102a and 102b indicated by the solid line in FIG. 9 gradually increases. On the other hand, since each actuator of the first hydraulic pressure unit 1A is inactive, the stroke simulator 5 is inactive, and the brake fluid flowing out from the hydraulic chamber 34 of the master cylinder 3 is connected to the connection fluid path 11 (first connection). It is supplied to the

rear wheel cylinders

102c and 102d via the liquid passage 11A). After time t2, the clearance between the friction member (brake pad) of the brake operating unit and the wheel-side rotating member (brake disc) is filled in the rear wheels RL and RR (the rear

wheel wheel cylinders

102c and 102d are finished filling) The pedal stroke S gradually increases as the pedal effort F increases, and the hydraulic pressure in the

rear wheel cylinders

102c and 102d indicated by the broken line in FIG. 9 hardly increases.

At time t3, the above stuffing ends. Therefore, after time t3, the rate of increase of S relative to the increase of F decreases, and the hydraulic pressure of the

rear wheel cylinders

102c, 102d gradually increases as F increases. Here, the rising speed of the hydraulic pressure of the

front wheel cylinders

102a and 102b by the second pump 81B is higher than the rising speed of the hydraulic pressure of the

rear wheel cylinders

102c and 102d by F, and is, for example, 1 to 5 MPa / s. The hydraulic pressure in the

front wheel cylinders

102a and 102b is higher than the hydraulic pressure in the

rear wheel cylinders

102c and 102d. The vehicle deceleration realized by the wheel cylinder hydraulic pressure of the front and rear wheels increases.

At time t4, the discharge pressure of the second pump 81B (the hydraulic pressure of the

front wheel cylinders

102a and 102b by the second pump 81B) reaches an upper limit (eg, 3.7 MPa. The following is an example for reference). . At this time, F is 200 N, S is approximately 30 mm, the hydraulic pressure of the

rear wheel cylinders

102c and 102d is 2.4 MPa, and the vehicle deceleration realized by the wheel cylinder hydraulic pressure of the front and rear wheels is 0.46G. It is. After time t4, the hydraulic pressure in the

front wheel cylinders

102a, 102b remains at the upper limit, and the hydraulic pressure in the

rear wheel cylinders

102c, 102d increases as F increases. The hydraulic pressure in the

front wheel cylinders

102a and 102b remains higher than the hydraulic pressure in the

rear wheel cylinders

102c and 102d. The vehicle deceleration achieved by the front and rear wheel cylinder hydraulic pressures increases slightly from 0.46G.

At time t5, F becomes 310N, and the hydraulic pressure in the

rear wheel cylinders

102c and 102d reaches the hydraulic pressure in the

front wheel cylinders

102a and 102b. Therefore, at times t3 to t5, a deceleration larger than the deceleration according to F occurs (F is boosted). After time t5, the check valve 710 opens according to the increase in the hydraulic pressure of the

rear wheel cylinders

102c, 102d, and the brake fluid flows from the master cylinder 3 side to the

front wheel cylinders

102a, 102b side. As a result, the hydraulic pressure in the

front wheel cylinders

102a and 102b increases in the same manner as the hydraulic pressure in the

rear wheel cylinders

102c and 102d. The brake fluid that has flowed out of the hydraulic chamber 34 of the master cylinder 3 is connected not only to the

rear wheel cylinders

102c and 102d but also to the front wheel cylinder 102a via the connection fluid passage 11 (first and second connection fluid passages 11A and 11B). , 102b. Therefore, the deceleration of the vehicle realized by the wheel cylinder hydraulic pressures of the front and rear wheels increases, and the rate of increase of S with respect to the increase of F increases.

Corresponding to F being held constant from time t6 to t7, S, P, and deceleration are also constant. Therefore, at times t5 to t7, deceleration corresponding to F occurs. At time t7, F starts to decrease. Brake fluid is returned from the

rear wheel cylinders

102c and 102d to the hydraulic pressure chamber 34 of the master cylinder 3 via the connection fluid path 11 (first connection fluid path 11A). On the other hand, the flow of brake fluid from the

front wheel cylinders

102a and 102b to the hydraulic chamber 34 is suppressed by the check valve 710. Therefore, after time t7, S gradually decreases as F decreases, and the hydraulic pressure in the

rear wheel cylinders

102c and 102d decreases, but the hydraulic pressure in the

front wheel cylinders

102a and 102b is maintained. The vehicle deceleration achieved by the front and rear wheel cylinder hydraulic pressures is slightly reduced. At time t8, F becomes 0. The pedal stroke S (detected value of the stroke sensor 91) becomes S0 or less. In addition, the brake lamp switch is switched from on to off. When the detection value input from the stroke sensor 91 to the second control unit 902 is equal to or less than the predetermined value S0, the second control unit 902 does not generate a relay drive signal. As a result, the operation of the second hydraulic pressure unit 1B is released. The relay 908 is switched from on to off, and energization of the second motor 80B and the on-off valve 71B is completed. The on-off valve 71B is opened and the second pump 81B is stopped. Brake fluid is returned from the

front wheel cylinders

102a, 102b to the hydraulic pressure chamber 34 of the master cylinder 3 via the connection fluid passage 11 (first and second connection fluid passages 11A, 11B). Therefore, after time t8, the hydraulic pressure in the

front wheel cylinders

102a, 102b rapidly decreases to 0, and the vehicle deceleration realized by the wheel cylinder hydraulic pressure in the front and rear wheels also decreases to 0.

Thus, the brake system 1 includes the second hydraulic unit 1B separately from the first hydraulic unit 1A. Normally, only the first hydraulic pressure unit 1A is activated to generate a brake hydraulic pressure, and a boost control that assists the pedal effort is executed. In a state where the boost control by the first hydraulic unit 1A has failed, the second hydraulic unit 1B is activated to generate the brake hydraulic pressure. As a result, as shown at times t2 to t5 in FIG. 9, a brake fluid pressure (front wheel wheel cylinder fluid pressure) higher than the brake fluid pressure (rear wheel wheel cylinder fluid pressure) due to the master cylinder fluid pressure is generated, and the pedal depression force Can continue assistance. That is, the failure notification unit 903 of the ECU 90 does not output a normal signal. The second control unit 902 detects the failure of the boost control, and operates the second pump 81B to operate the on-off valve 71B in the closing direction when the brake pedal 100 is operated. Therefore, since the brake hydraulic pressure is supplied to the wheel cylinder 102 (in the present embodiment, the front wheels FL and FR) by the second hydraulic pressure unit 1B, the boost control can be continued as a whole of the brake system 1. Thus, the second hydraulic pressure unit 1B functions as an auxiliary hydraulic pressure unit for failure.

As shown at times t3 to t4 in FIG. 9, the pressure increase speed of the

front wheel cylinders

102a and 102b by the second pump 81B is, for example, 1 to 5 MPa / s, and the maximum wheel in brake control for vehicle motion control It can be set lower than the cylinder pressure increase speed. This is because the original function of the second hydraulic pressure unit 1B is assistance in the case of failure of boost control by the first hydraulic pressure unit 1A (continuation of boost control). This is because such a pressure increase rate is not necessary. Therefore, the output or performance of the second pump 81B (second motor 80B) can be set lower than the output or performance of the first pump 81A (first motor 80A). Thereby, the structure of the 2nd hydraulic-pressure unit 1B can be simplified and size reduction can be achieved.

As shown at time t4 in FIG. 9, when the boost control by the first hydraulic unit 1A fails, a deceleration of 0.4G or more can be realized when the pedal force F is 200N. The pedal stroke S at this time is approximately 30 mm, and S is suppressed within 50 mm. Therefore, it is possible to shorten the pedal stroke. In other words, a large deceleration can be obtained with a small pedaling force and a short pedal stroke. Assuming that the master cylinder 3 is provided with a booster such as an electric booster, the operation signal of the brake pedal 100 is used as a trigger in the state where the failure of the boost control by the first hydraulic unit 1A is detected. It is also conceivable to activate the booster. However, in this case, since the booster is interlocked with the master cylinder 3 (using the brake fluid in the hydraulic pressure chamber 34), it is not easy to shorten the pedal stroke. On the other hand, in the present embodiment, the second hydraulic pressure unit 1B can increase the pressure of the wheel cylinder 102 independently of the operation of the master cylinder 3 (not using the brake fluid in the hydraulic pressure chamber 34). For this reason, when the pressure of the wheel cylinder 102 is increased by the second hydraulic unit 1B when the brake pedal 100 is operated in the above-described failure state, the amount of brake fluid delivered from the master cylinder 3 can be reduced. Therefore, it is easy to shorten the pedal stroke.

The second hydraulic unit 1B has a check valve 710 in parallel with the on-off valve 71B. As a result, even when the master cylinder hydraulic pressure by the depression operation of the brake pedal 100 becomes higher than the maximum wheel cylinder hydraulic pressure achievable by the second pump 81B, as shown at times t5 to t6 in FIG. Brake fluid can be supplied from the cylinder 3 to the wheel cylinder 102 through the check valve 710. Therefore, the stroke of the brake pedal 100 is not hindered, and a more natural pedal operation feeling is obtained. On the other hand, even when the output or performance of the second pump 81B (second motor 80B) is set low, for example, a sufficient braking force can be realized. That is, at least at the initial stage (time t2 to t5) of the depression of the brake pedal 100, the brake fluid pressure (front wheel wheel cylinder fluid pressure) higher than the brake fluid pressure (rear wheel wheel cylinder fluid pressure) due to the master cylinder fluid pressure is changed. It can be generated by two pumps 81B. Thereafter (time t5 to t6), even if the master cylinder hydraulic pressure becomes higher than the maximum wheel cylinder hydraulic pressure by the second pump 81B, the master cylinder hydraulic pressure can be supplied to the wheel cylinder 102.

The second hydraulic pressure unit 1B may be configured to increase the pressure of the wheel cylinders 102 of all wheels (not only the front wheels FL and FR but also the rear wheels RL and RR). For example, there is an on-off valve 71B on the connecting fluid passage 11 connected to the

wheel cylinders

102c, 102d of the rear wheels RL, RR, and the second discharge liquid is provided between the on-off valve 71B and the

rear wheel cylinders

102d, 102d. The path 13B may be connected. In the present embodiment, the second hydraulic pressure unit 1B (second pump 81B) is connected to the

wheel cylinders

102a, 102b of only a part (front wheels FL, FR) of all the wheels, and this part of the wheel cylinders 102 is increased. Press. Therefore, the amount of discharge liquid of the second pump 81B necessary for increasing the pressure of the wheel cylinder 102 can be reduced. Accordingly, the rotation speed of the second motor 80B can be suppressed. By suppressing the motor rotation speed, it is possible to reduce sound vibration. The master cylinder 3 (hydraulic pressure chamber 34) is connected to the

wheel cylinders

102c, 102d of some other wheels (rear wheels RL, RR) of all the wheels without the second hydraulic pressure unit 1B (open / close valve 71B). The master cylinder hydraulic pressure directly acts on the wheel cylinder 102. Therefore, the brake pedal 100 can stroke appropriately, and a more natural pedal operation feeling can be obtained. The wheels connected to the second hydraulic pressure unit 1B may include both front wheels FL and FR and rear wheels RL and RR. On the other hand, when the second hydraulic unit 1B is connected to only one of the front wheels FL, FR and the rear wheels RL, RR, yaw moment is generated in the vehicle when the wheel cylinder 102 is pressurized by the second hydraulic unit 1 Can be easily suppressed. For example, the second hydraulic pressure unit 1B may increase the pressure of the

wheel cylinders

102c and 102d for only the rear wheels RL and RR. In the present embodiment, the second hydraulic pressure unit 1B increases the pressure of the

wheel cylinders

102a, 102b for the front wheels FL, FR only. Therefore, the deceleration of the vehicle can be effectively generated as compared with the case where the

wheel cylinders

102c and 102d with only the rear wheels RL and RR are increased.

In this embodiment, there are two second pumps 81B. Therefore, by disposing the second pump 81B for each system, a valve for shutting off the liquid path on the discharge side of the second pump 81B between the systems becomes unnecessary. Thereby, the structure of the 2nd hydraulic-pressure unit 1B can be simplified and size reduction can be achieved. A second motor 80B may be provided for each second pump 81B. In the present embodiment, there is one second motor 80B, and two second pumps 81B are driven by one second motor 80B. Therefore, the configuration can be simplified and the size can be reduced.

The second control unit 902 detects the stroke sensor 91 as a signal (pedal operation signal) indicating that the brake pedal 100 has been operated in a state where the failure of the boost control by the first hydraulic unit 1A is detected. Using the signal as a trigger, the second pump 81B and the on-off valve 71B of the second hydraulic unit 1B are relay-driven to increase the pressure in the wheel cylinder 102. The control system of the second hydraulic pressure unit 1B is a simple system in which the relay 908 is turned on only while the driver steps on the brake pedal 100, and the relay 908 is turned off when the driver releases the brake pedal 100. Thus, the operation method of the second hydraulic pressure unit 1B is simple and does not require complicated control. Therefore, complication of the brake system 1 as a countermeasure against the failure can be suppressed. Here, “complication” is from both a structural and control viewpoint. For example, a brake system is also conceivable in which the second hydraulic unit 1B is also provided with an ECU and the mutual failure state is monitored with the ECU 90 of the first hydraulic unit 1A. In this case, the second hydraulic pressure unit 1B may be increased in size, the brake system may be complicated, or a mutual monitoring program may be required, resulting in an increase in cost. In contrast, in the brake system 1 of the present embodiment, the second control unit 902 generates and outputs an actuator drive signal based on the input (presence / absence) of two signals (failure signal and pedal operation signal). A circuit is sufficient. For this reason, the second control unit 902 does not need to have a complicated control law or a high processing capability, and can simplify or omit a program for realizing the control law and a memory for storing the program. Therefore, the second control unit 902 can be configured by a simple circuit (in this embodiment, a relay sequence). Note that the control system of the second hydraulic pressure unit 1B is not a system that monitors the state of the second motor 80B or the on-off valve 71B and performs feedback control thereof (an open type system that performs sequence control). And sensors can be omitted, and the input interface can be simplified and omitted. The signal output from the second control unit 902 is a signal for switching on / off of the relay 908, and does not particularly control the rotation speed of the second motor 80B. For this reason, the output interface can be simplified or omitted. Therefore, an ECU or a sensor for controlling the operation of the second hydraulic unit 1B can be omitted, and thereby the second hydraulic unit 1B can be downsized. In addition, the configuration of the brake system 1 can be simplified and the cost can be reduced. When the boost control fails, the failure notification unit 903 outputs a signal (failure signal) indicating the occurrence of the failure, and when the second control unit 902 receives the failure signal, the failure notification unit 903 outputs the failure. May be detected. Further, as a pedal operation signal, a detection signal such as a brake lamp switch provided in the brake pedal 100 or the like may be used. If a detection signal such as a brake lamp switch independent of the ECU 90 is used, the reliability of the ECU 90 when the power supply fails can be improved.

The second control unit 902 is arranged as an independent circuit inside the ECU 90 of the first hydraulic unit 1A. Therefore, further miniaturization of the second hydraulic unit 1B can be achieved. As described above, since the control system of the second hydraulic unit 1B including the second control unit 902 can be simplified, it is easy to arrange this control system inside the ECU 90 of the first hydraulic unit 1A. is there. The drive circuit 907 (relay 908) of the second hydraulic unit 1B is also arranged as an independent circuit inside the ECU 90 of the first hydraulic unit 1A. Thereby, the same effect as the above is obtained. The second controller 902 and the drive circuit 907 may be disposed in the second hydraulic unit 1B (inside the solenoid case 600). In this case, the space inside the ECU 90 in the first hydraulic unit 1A can be saved. Further, the second control unit 902 and the drive circuit 907 (relay 908) may be separately arranged between the

hydraulic units

1A and 1B. If the second control unit 902 and the drive circuit 907 are arranged in the same hydraulic unit, the control configuration for countermeasure against failure can be completed in the same hydraulic unit. The second control unit 902 may be arranged as an independent circuit in a vehicle-side controller outside the brake system 1 (for example, an ECU for automatic driving in the advanced driving support system ADAS). In this case, the failure of the first hydraulic pressure unit 1A (the state where the boost control is not activated) is detected by the second control unit 902 in the vehicle-side controller, so that the brake system 1 takes measures against the failure. Therefore, it can suppress complicating. Similarly, the drive circuit 907 may be disposed in the controller on the vehicle side. On the other hand, if the second control unit 902 and the drive circuit 907 are arranged in the first hydraulic unit 1A or the second hydraulic unit 1B, the control configuration for the failure countermeasure is completed in the brake system 1. Can do. Note that the second controller 902 and the drive circuit 907 may be arranged in the master cylinder unit 1C.

The ECU 90 may include a failure detection unit for executing an initial check as to whether or not the boost control by the second hydraulic unit 1B has failed. For example, when the brake pedal 100 is operated while the vehicle is stopped or at a predetermined vehicle speed (a vehicle speed that is less likely to cause a sense of incongruity when an unintended braking force is generated) after the ignition is turned on, The normal signal output from the failure notification unit 903 to the second control unit 902 is interrupted. At this time, it is detected whether or not the second hydraulic pressure unit 1B operates normally. In this case, it is preferable to ensure the performance of the second hydraulic pressure unit 1B (second motor 80B, etc.) that can withstand an initial check that is repeated to a certain extent.

Note that the first hydraulic unit 1A and the second hydraulic unit 1B may be configured as one hydraulic unit (for example, by being connected and fixed to each other or sharing the same housing). In this case, the same effect as described above can be obtained. In the present embodiment, the two

hydraulic units

1A and 1B are separate bodies and are connected to each other by a brake pipe 10. The second hydraulic unit 1B is located between the wheel cylinder 102 (of the front wheels FL, FR) and the first hydraulic unit 1A. In other words, the second hydraulic unit 1B is on the wheel cylinder 102 side with respect to the first hydraulic unit 1A. In the connection liquid path 11, the on-off valve 71B is on the wheel cylinder 102 side with respect to the shutoff valve 71A. Therefore, when the boost control by the first hydraulic unit 1A fails, the second hydraulic unit 1B (second pump 81B) adds the wheel cylinder 102 from a position relatively close to the wheel cylinder 102 in the connecting fluid path 11. Will be pressed. For this reason, there is little flow path resistance by the piping 10, and the pressure increase responsiveness of the wheel cylinder 102 can be improved correspondingly.

The specific configuration of each

unit

1A, 1B, 1C for achieving the above-described effects is not limited to that of this embodiment. For example, the pump 81 is not limited to a plunger pump, and may be a gear pump, for example. If it is a plunger pump like this embodiment, responsiveness is comparatively high.

[Second Embodiment]
The second control unit 902 of this embodiment implements control by software instead of the relay sequence. FIG. 10 shows the flow of control executed by a program built in the second control unit 902. In step S1, it is determined whether a normal signal is received from the first hydraulic unit 1A. If the normal signal is continuously received (for example, a predetermined time or longer), S1 is repeatedly executed. If the normal signal is not continuously received, it is detected that the boost control by the first hydraulic pressure unit 1A has failed, and the process proceeds to S2. In S2, the alert signal is turned on, an alert is displayed on the instrument panel, and an alarm sound is generated. In S3, it is determined whether or not a pedal operation signal is input. If it has been input, the process proceeds to S4. If it has not been input, the process proceeds to S5. In S4, the relay drive signal is turned on and the relay 908 is turned on. In S5, the relay drive signal is turned off and the relay 908 is turned off. Other configurations of the brake system 1 are the same as those in the first embodiment.

Next, the function and effect will be described. Since the program is simple as described above, the microprocessor on which the program is mounted can be simplified and downsized. Further, as in the first embodiment, an ECU or the like for controlling the operation of the second hydraulic unit 1B can be omitted. When the boost control by the first hydraulic unit 1A fails, the failure notification unit 903 outputs a failure signal, and the second control unit 902 detects the failure when receiving the failure signal in step S1. Then, the process may proceed to step S2. Other functions and effects are the same as those of the first embodiment.

[Third Embodiment]
As shown in FIG. 11, the electromagnetic valve 7B of the second hydraulic unit 1B has a communication valve 73B. The communication valve 73B is a normally closed on / off valve. The communication valve 73B may be a proportional control valve. There is one second pump 81B, and it is driven by one second motor 80B. One end of the second discharge liquid passage 13B is connected to the discharge portion of the second pump 81B. The other end of the second discharge liquid path 13B is a second connection liquid path 11sB, which is connected between the on-off valve 71sB and the second output port 62s. The communication liquid path 13pB is a second connection liquid path 11pB between the on-off valve 71pB and the second output port 62p, and a second connection liquid path 11sB between the on-off valve 71sB and the second output port 62s. Connecting. A communication valve 73B is provided on the communication liquid path 13pB. On the power supply line 909, the coil of the second motor 80B, the solenoid of the on-off valve 71B, and the solenoid of the communication valve 73B are connected in parallel.

The second hydraulic unit 1B is located between the master cylinder unit 1C and the first hydraulic unit 1A. In other words, the first hydraulic unit 1A is on the wheel cylinder 102 side with respect to the second hydraulic unit 1B. Master cylinder piping 10M connects master cylinder 3 and second hydraulic unit 1B. One end of the master cylinder pipe 10M is connected to the supply port 302, and the other end of the master cylinder pipe 10M is connected to the second input port 61. The relay pipe 10I connects the second hydraulic unit 1B and the first hydraulic unit 1A. One ends of the relay pipes 10Ip and 10Is are connected to the

second output ports

62p and 62s, respectively, and the other ends of the relay pipes 10Ip and 10Is are connected to the

first input ports

41P and 41S, respectively. The wheel cylinder pipe 10W connects the first hydraulic unit 1A and the wheel cylinders 102 of the wheels FL to RR. One end of each of the wheel cylinder pipes 10Wa to 10Wd is connected to each of the first output ports 42a to 42d, and the other end of each of the wheel cylinder pipes 10Wa to 10Wd is connected to each of the wheel cylinders 102a to 102d. The on-off valve 71B is in the connection liquid path 11 on the master cylinder 3 side with respect to the shutoff valve 71A. In other words, the shut-off valve 71A is in the connection liquid path 11 on the wheel cylinder 102 side with respect to the on-off valve 71B. The second pump 81B can supply brake fluid to the connection fluid path 11 between the on-off valve 71B and the shutoff valve 71A. Other configurations of the brake system 1 are the same as those in the first embodiment.

Next, the function and effect will be described. Based on FIG. 12, the operation of the brake system 1 when the boost control by the first hydraulic unit 1A is not normally operable (not operating) will be described. When the detection value of the stroke sensor 91 exceeds the predetermined value S0 (or the brake lamp switch detection signal is input) at time t2, the second control unit 902 generates a relay drive signal and outputs it to the relay 908. As a result, the relay 908 is switched from OFF to ON, and energization of the second motor 80B, the on-off valve 71B, and the communication valve 73B is started. The on-off valve 71B is closed, the communication valve 73B is opened, and the second pump 81B is operated. The brake fluid boosted by the second pump 81B is supplied to the second connection fluid passage 11B of both systems, and then the front and rear wheel foils are connected via the relay piping 10I, the first connection fluid passage 11A, and the wheel cylinder piping 10W. It is supplied to the cylinders 102a to 102d. Therefore, after time t2, the hydraulic pressure in the front and rear wheel wheel cylinders 102 indicated by the solid line in FIG. 12 gradually increases. On the other hand, since the on-off valve 71B is closed, the outflow of the brake fluid from the hydraulic chamber 34 of the master cylinder 3 is suppressed. After time t2, the increase amount of the pedal stroke S is small with respect to the increase of the pedaling force F.

After time t3, the rate of increase of the hydraulic pressure of the front and rear wheel cylinders 102 shown by the solid line in FIG. 12 is higher than the rate of increase of the hydraulic pressure of the master cylinder 3 by F (shown by the broken line), for example, 1-5 MPa / s. is there. Further, the hydraulic pressure in the wheel cylinder 102 is higher than the hydraulic pressure in the master cylinder 3. At time t4, the discharge pressure of the second pump 81B (the hydraulic pressure of the wheel cylinder 102 increased by the second pump 81B) is a mechanical upper limit value (for example, 3.5 MPa. The following is an example for reference) .) At this time, F is 200 N, S is approximately 20 mm, and the vehicle deceleration realized by the wheel cylinder hydraulic pressure of the front and rear wheels FL to RR is 0.48 G. After time t4, the hydraulic pressure in the front and rear wheel wheel cylinders 102 remains at the upper limit value, and the hydraulic pressure in the master cylinder 3 increases as F increases. At time t5, F becomes 290N, and the hydraulic pressure in the master cylinder 3 reaches the hydraulic pressure in the wheel cylinder 102. After time t5, the check valve 710 opens according to the increase in the hydraulic pressure in the master cylinder 3, and the brake fluid flows from the master cylinder 3 side to the wheel cylinder 102 side, so that the hydraulic pressure in the wheel cylinder 102 is increased. It rises as well as the hydraulic pressure of 3. Therefore, the deceleration of the vehicle realized by the wheel cylinder hydraulic pressure increases, and the rate of increase of S with respect to the increase of F increases. Other changes are the same as in the first embodiment.

¡The second hydraulic pressure unit 1B pressurizes the wheel cylinders 102 of all the wheels FL to RR. Since the same brake fluid pressure acts on all wheels, a stable braking force can be secured. As shown at time t4 in FIG. 12, the pedal force F is 200 N, and the wheel cylinder hydraulic pressure of each wheel is 3.5 MPa, which is lower than that of the first embodiment, while the deceleration is 0.48 G, which is higher than that of the first embodiment. high. At time t5, the pedaling force F is 290N which is smaller than that of the first embodiment (310N), while the deceleration is 0.48G, which is the same as or higher than that of the first embodiment. In other words, a greater deceleration can be achieved with a smaller pedal effort.

At least at the beginning of the pressure increase by the second pump 81B, the master cylinder hydraulic pressure does not act on the wheel cylinders 102 of all the wheels FL to RR. Since the on-off valve 71B is closed, the outflow of brake fluid from the hydraulic chamber 34 of the master cylinder 3 is suppressed. Therefore, the pedal stroke can be shortened as compared with the one in which the master cylinder hydraulic pressure acts on some of the wheels (first embodiment). For example, as shown at time t4 in FIG. 12, the pedaling force F is 200 N, and the pedal stroke S is approximately 20 mm, which is shorter than that of the first embodiment.

The second hydraulic unit 1B is located between the master cylinder 3 and the first hydraulic unit 1A. Compared to the first embodiment, since the second hydraulic pressure unit 1B (open / close valve 71B) is closer to the master cylinder 3, the pedal stroke can be made shorter during control by the second hydraulic pressure unit 1B. The first hydraulic unit 1A is located between the wheel cylinder 102 and the second hydraulic unit 1B. In normal times when the boost control by the first hydraulic unit 1A has not failed, the first hydraulic unit 1A (first pump 81A) moves the wheel cylinder 102 from a position closer to the wheel cylinder 102 than in the first embodiment. Since the pressure is applied, the flow path resistance by the brake pipe 10 is small. For this reason, the pressure increase response of the wheel cylinder 102 at the normal time is improved.

The number of the second pump 81B is one, and the brake fluid can be supplied to the second connection fluid passage 11B of both systems via the communication fluid passage 13pB. Thereby, the structure of the 2nd hydraulic-pressure unit 1B can be simplified and size reduction can be achieved. By installing the communication valve 73B in the communication liquid path 13pB, the systems can be shut off. The second discharge liquid path 13B may be connected to the second connection liquid path 11B of either system or may be connected to the communication liquid path 13pB. Other functions and effects are the same as those of the first embodiment.

[Fourth Embodiment]
As shown in FIG. 13, there is one second pump 81B and it is driven by one second motor 80B. One end of the second discharge liquid passage 13B is connected to the discharge portion of the first pump 81A. The other end side of the second discharge liquid passage 13B branches into two. Each of the branch liquid paths 13pB and 13sB is a second connection liquid path 11B and is connected between the on-off valve 71B and the second output port 62. A check valve 73B is provided above each of the branch liquid passages 13pB and 13sB. The check valve 73B allows the flow of brake fluid from the discharge portion of the second pump 81B toward the second connection fluid path 11B and suppresses the flow in the opposite direction. The second hydraulic pressure unit 1B has a relief circuit in the second discharge liquid path 13B. The relief circuit includes a relief liquid passage 130, a relief valve 730, and a check valve 73B. The relief liquid path 130 is the second discharge liquid path 13B, and connects the discharge part of the second pump 81B and the check valve 73B to the second suction liquid path 12B. The relief valve 730 is above the relief fluid path 130. The valve body of the relief valve 730 is always urged in the valve closing direction by a spring as an elastic body. The second suction fluid passage 12B is connected to the reservoir 64 (reservoir tank 2), and the fluid pressure in the second suction fluid passage 12B is low (atmospheric pressure). When the fluid pressure in the second discharge fluid passage 13B becomes a predetermined value (relief pressure) or more, the urging force due to the difference between the fluid pressure in the second suction fluid passage 12B and the fluid pressure in the second discharge fluid passage 13B is the urging force of the spring. The valve body moves above the threshold value, and the relief valve 730 opens. The relief pressure is preset to a hydraulic pressure equivalent to the required braking force (for example, 3.7 MPa) when the second hydraulic unit 1B continues the boost control when the boost control by the first hydraulic unit 1A fails. The Other configurations of the brake system 1 are the same as those in the first embodiment.

Next, the function and effect will be described. The number of the second pump 81B is one, and the brake fluid can be supplied to the second connection fluid passage 11B of both systems via the second discharge fluid passage 13B (branching fluid passages 13pB, 13sB). Thereby, the structure of the 2nd hydraulic-pressure unit 1B can be simplified and size reduction can be achieved. By installing a check valve 73B in each of the branch liquid passages 13pB and 13sB, it is possible to block the flow of brake fluid between the systems. In addition, in order to be able to shut off between the systems, one electromagnetic valve may be installed in each of the branch liquid passages 13pB and 13sB instead of the check valves 73pB and 73sB.

The relief valve 730 opens at a hydraulic pressure (relief pressure) corresponding to the required braking force, and allows the brake fluid in the second discharge fluid passage 13B to escape to the reservoir 64 (reservoir tank 2) side, which is a low-pressure part. . Thereby, at the time of control by the 2nd hydraulic pressure unit 1B, the excessive pressure increase of the wheel cylinder 102 and the lock | rock of the 2nd motor 80B can be suppressed. That is, during the control by the second hydraulic pressure unit 1B, the brake system 1 continues to drive the second motor 80B while the brake pedal 100 is being operated. The rotation of the second pump 81B is not stopped by the control of the second motor 80B, but is stopped due to a mechanical limit. That is, the second motor 80B automatically stops when the load on the second pump 81B exceeds a certain level. Here, in order to make the wheel cylinder hydraulic pressure equivalent to the necessary braking force, the second motor 80B is stopped so as to stop (lock) when the discharge side of the second pump 81B reaches the hydraulic pressure equivalent to the braking force. It is also conceivable to set the motor 80B or the like. However, in this case, a large current continues to flow through the second motor 80B, which may reduce durability. On the other hand, in the brake system 1 of the present embodiment, the relief valve 730 releases the brake fluid with a hydraulic pressure corresponding to the required braking force, so that the load is suppressed and the second motor 80B continues to rotate. Thereby, since the current flowing through the second motor 80B can be suppressed to a certain set value or less, it is possible to suppress a decrease in durability. Further, the brake fluid discharged from the second pump 81B is discharged from the relief valve 730 to the reservoir 64 (reservoir tank 2) side instead of the hydraulic chamber 34 of the master cylinder 3. For this reason, it can suppress that reaction force is transmitted to the brake pedal 100 by relief of brake fluid, and brake operation feeling falls.

Here, when the second connection liquid path 11B and the relief valve 730 are always in communication, the relief valve 730 is automatically opened when the liquid pressure in the second connection liquid path 11B tends to be higher than the relief pressure. Therefore, the brake fluid is discharged from the second connection fluid passage 1B through the relief valve 730, the fluid pressure in the second connection fluid passage 11B is not higher than the relief pressure, and the wheel cylinder fluid pressure is increased higher than the relief pressure. It becomes difficult to press. On the other hand, in the present embodiment, there is a check valve 73B between the second discharge liquid passage 13B and the connection portion with the relief liquid passage 130 and the connection portion with the second connection liquid passage 11B. The check valve 73B suppresses the flow of brake fluid from the second connection fluid path 1B to the relief valve 730. Therefore, the hydraulic pressure (foil cylinder hydraulic pressure) in the second connection liquid passage 1B can be increased higher than the relief pressure. As described above, the check valve 73B has a function of increasing the hydraulic pressure (foil cylinder hydraulic pressure) of the connection liquid passage 11 higher than the relief pressure, in addition to the function of cutting off the systems. Since the check valve 73B has a plurality of functions, the number of parts of the second hydraulic unit 1B can be reduced and the configuration can be simplified. Note that a relief circuit similar to that of this embodiment may be provided in the second discharge liquid passage 13B of the first to third embodiments. Other functions and effects are the same as those of the first embodiment.

[Fifth Embodiment]
As shown in FIG. 14, the second hydraulic pressure unit 1B does not have the relief liquid passage 130 and the relief valve 730. Instead, the on-off valve 71B functions as a relief valve. When the relay 908 is turned on and the on-off valve 71B is closed when the boost control by the first hydraulic unit 1A fails, the current flowing through the solenoid of the on-off valve 71B is set to a certain value or less. Specifically, “the on-off valve 71B opens when the hydraulic pressure on the wheel cylinder 102 side is higher than the hydraulic pressure on the side of the master cylinder 3 relative to the on-off valve 71B in the second connection liquid path 11B” Such a current value is set so that the on-off valve 71B is energized. Other configurations of the brake system 1 are the same as those in the fourth embodiment.

Next, the function and effect will be described. During the control by the second hydraulic pressure unit 1B, if the hydraulic pressure on the wheel cylinder 102 side is higher than the hydraulic pressure on the master cylinder 3 side relative to the open / close valve 71B, the open / close valve 71B is automatically opened. . As shown by an arrow in FIG. 14, a part of the brake fluid discharged from the second pump 81B is discharged to the master cylinder 3 side through the on-off valve 71B. As a result, the wheel cylinder hydraulic pressure is suppressed from becoming higher than a certain level with respect to the master cylinder hydraulic pressure. Therefore, excessive pressure increase of the wheel cylinder 102 and locking of the second motor 80B can be suppressed. In the first to third embodiments, as in the present embodiment, the on-off valve 71B may be set to function as a relief valve. Other functions and effects are the same as those of the fourth embodiment.

[Sixth Embodiment]
As shown in FIG. 15, the second hydraulic unit 1B has a relief circuit in the second discharge liquid passage 13B. The relief circuit includes a relief liquid path 130, a relief valve 730, and a check valve 76. The check valve 76 is above the second discharge liquid path 13B. The check valve 76 allows the flow of brake fluid from the discharge portion of the second pump 81B toward the second connection fluid path 11B and suppresses the flow in the opposite direction. The relief liquid path 130 is the second discharge liquid path 13B, and connects the discharge part of the second pump 81B and the check valve 76 to the second suction liquid path 12B. The relief valve 730 is above the relief fluid path 130. The configuration of the relief valve 730 is the same as that of the fourth embodiment.

The electromagnetic valve 7B of the second hydraulic unit 1B has an output control valve 78B. The output control valve 78B is a normally closed on / off valve. The output control valve 78B may be a proportional control valve. The output control valve 78B is between the check valve 76 and the second discharge liquid passage 13B, which is connected to the second connection liquid passage 11sB. On the power supply line 909, the coil of the second motor 80B, the solenoid of the on-off valve 71B, the solenoid of the communication valve 73B, and the solenoid of the output control valve 78B are connected in parallel.

The second hydraulic unit 1B has a fast fill mechanism. The fast fill mechanism includes a bypass liquid path 18B, a replenishment liquid path 19B, a piston 66, a coil spring 67, a seal member 68, and an output control valve 78B. One end of the bypass liquid path 18B is a second connection liquid path 11sB and is connected between the second input port 61s and the on-off valve 71sB. The other end of the bypass liquid path 18B is a second discharge liquid path 13B and is connected between the check valve 76 and the output control valve 78B. Above the bypass liquid path 18B is a cylinder 604. The cylinder 604 has a stepped cylindrical shape. The large diameter portion of the cylinder 604 is on the second connection liquid passage 11sB side, and the small diameter portion is on the second discharge liquid passage 13B side. The cylinder 604 has a first seal groove 607 in the large diameter portion and a second seal groove 608 in the small diameter portion. Each of the

seal grooves

607 and 608 has an annular shape extending in the direction around the axis of the cylinder 604 (hereinafter referred to as the circumferential direction). The piston 66 is installed inside the cylinder 604 and can reciprocate in the axial direction. The piston 66 has a stepped cylindrical shape. The small diameter portion of the piston 66 is fitted to the small diameter portion of the cylinder 604, and the large diameter portion of the piston 66 is fitted to the large diameter portion of the cylinder 604. The piston 66 has two recesses 661 and 662 separated by a partition wall 660. The first recess 661 opens on the large diameter portion side of the piston 66, and the second recess 662 opens on the small diameter portion side. A hole 665 penetrates the large-diameter portion of the piston 66, which is the peripheral wall of the first recess 661. There are a plurality of holes 665 in the circumferential direction.

The cylinder 604 is divided into a positive pressure chamber 691, a back pressure chamber 692, and a variable volume chamber 693 by the piston 66. The positive pressure chamber 691 is on the large diameter portion side of the cylinder 604 with respect to the piston 66, and the back pressure chamber 692 is on the small diameter portion side. The variable volume chamber 693 is located between the outer peripheral surface of the small diameter portion of the piston 66 and the inner peripheral surface of the large diameter portion of the cylinder 604. The seal member 68 is a rod seal U-packing or V-packing, and is installed in each of the

seal grooves

607 and 608. The lip of the seal member 68 is in contact with the outer peripheral surface of the piston 66. The seal member 68 of the first seal groove 607 suppresses the flow of brake fluid from the positive pressure chamber 691 to the variable volume chamber 693 on the outer peripheral side of the large diameter portion of the piston 66, and allows the flow in the opposite direction. The seal member 68 of the second seal groove 608 suppresses the flow of brake fluid from the back pressure chamber 692 toward the variable volume chamber 693 on the outer peripheral side of the small diameter portion of the piston 66, and allows the flow in the opposite direction. The coil spring 67 is installed in the back pressure chamber 692, and always urges the piston 66 toward the positive pressure chamber 691 (the side where the volume of the positive pressure chamber 691 decreases). One end of the replenishing liquid channel 19B is connected to the variable volume chamber 693 and is always open to the variable volume chamber 693. The other end of the replenishing liquid path 19B is connected to the second suction liquid path 12B (reservoir 64). The housing 60 is provided with a valve 761 for bleeding air from the variable volume chamber 693 and a valve 762 for bleeding air from the back pressure chamber 692. The valve 761 is connected to the replenishing liquid path 19B, and the valve 762 is connected to the other end side (the side connected to the second discharge liquid path 13B) of the bypass liquid path 18B. The other configuration of the brake system 1 is the same as that of the third embodiment.

Next, the function and effect will be described. If the brake pedal 100 is depressed when the boost control by the first hydraulic unit 1A fails, the relay 908 switches from OFF to ON, and the second motor 80B, the on-off valve 71B, the communication valve 73B, and the output control valve 78B. Is energized. The on-off valve 71B is closed, the communication valve 73B and the output control valve 78B are opened, and the second pump 81B is operated. In the initial stage of the depression of the brake pedal 100, the master cylinder 3 is generated and the piston 66 is actuated by the master cylinder hydraulic pressure supplied to the positive pressure chamber 691 (stroke toward the back pressure chamber 692). Brake fluid flows out of This brake fluid is supplied to the second connection fluid passage 11sB through the second discharge fluid passage 13B (output control valve 78B), and is supplied to the wheel cylinder 102 via the connection fluid passage 11. As a result, the foil cylinder 102 is stuffed, so that the pressure increase response of the wheel cylinder 102 by the second pump 81B can be improved.

That is, the fluid pressure of the positive pressure chamber 691 acts on the portion of the piston 66 facing the positive pressure chamber 691, and the force due to this fluid pressure tries to move the piston 66 to the back pressure chamber 692. The hydraulic pressure of the back pressure chamber 692 acts on the portion facing the back pressure chamber 692, and the force by this hydraulic pressure tries to move the piston 66 to the positive pressure chamber 691 side. In the initial stage of the depression operation of the brake pedal 100, the pressure increase response of the wheel cylinder 102 by the second pump 81B is low due to an insufficient rotation speed of the second motor 80B. For this reason, the second connection fluid on the second output port 62 side compared to the brake fluid pressure (master cylinder fluid pressure) of the second connection fluid passage 11B on the second input port 61 side with respect to the closed on-off valve 71B. The brake fluid pressure (wheel cylinder fluid pressure) on the road 11B is not sufficiently high. Therefore, the force due to the fluid pressure in the positive pressure chamber 691 (master cylinder fluid pressure) exceeds the force due to the fluid pressure in the back pressure chamber 692 (wheel cylinder fluid pressure) (and the sum of the biasing force of the coil spring 67), The piston 66 is movable toward the back pressure chamber 692.

Between the bypass liquid path 18B and the second discharge liquid path 13B from the connection site with the bypass liquid path 18B to the connection site with the second connection liquid path 11sB, the second connection liquid is connected in parallel with the on-off valve 71B. Connected to the path 11sB and functions as a bypass liquid path that bypasses the on-off valve 71B. This bypass fluid path is connected to the second connection port 11B on the second input port 61 or the master cylinder 3 side with respect to the on-off valve 71B, and on the second output port 62 or the wheel cylinder 102 side on the side of the on-off valve 71B. The second connection liquid path 11B is connected. By operating the piston 66 on the bypass fluid path, the brake fluid is supplied toward the wheel cylinder 102. A function equivalent to the brake fluid flowing from the master cylinder 3 to the wheel cylinder 102 via the bypass fluid path (bypassing the on-off valve 71B) is realized. The output control valve 78B is on the bypass liquid passage, and enables the operation of the piston 66 by opening the valve, and suppresses the operation of the piston 66 by closing the valve. In other words, it controls the presence or absence of the output of the fast fill mechanism. As the bypass liquid path, a liquid path that is connected to the second connection liquid path 11sB in parallel with the on-off valve 71B and bypasses the on-off valve 71B may be provided independently of the second discharge liquid path 13B. In the present embodiment, the circuit configuration can be simplified by using a part of the second discharge liquid path 13B also as the bypass liquid path.

During control by the second hydraulic pressure unit 1B, a certain amount of brake fluid flows into the positive pressure chamber 691 from the master cylinder 3 (hydraulic pressure chamber 34S). Therefore, the brake pedal 100 can stroke appropriately. On the other hand, since the amount of brake fluid flowing from the master cylinder 3 into the positive pressure chamber 691 is limited, an excessive increase in the pedal stroke is suppressed. Therefore, the brake operation feeling can be improved while shortening the pedal stroke.

Piston 66 is stepped. The hydraulic pressure in the back pressure chamber 692 (hydraulic pressure on the wheel cylinder 102) is larger than the area (large diameter portion) of the piston 66 that receives the hydraulic pressure in the positive pressure chamber 691 (hydraulic pressure on the master cylinder 3 side). The area of the part (small diameter part) that receives is smaller. Therefore, the hydraulic pressure on the side of the wheel cylinder 102 output from the cylinder 604 becomes higher than the hydraulic pressure on the side of the master cylinder 3 input to the cylinder 604 (ignoring the biasing force of the coil spring 67). Therefore, the pressure increasing response of the wheel cylinder 102 can be further improved. Further, even after the number of rotations of the second motor 80B is sufficiently increased and the discharge pressure of the second pump 81B (hydraulic pressure of the back pressure chamber 692) is sufficiently increased, the hydraulic pressure (master cylinder fluid) of the positive pressure chamber 691 is increased. It is possible to keep the piston 66 stopped at a fixed position on the back pressure chamber 692 side by pressure. Therefore, it is easy to stabilize the operation of the piston 66 during the control by the second hydraulic unit 1B. When the control by the second hydraulic pressure unit 1B is completed, the piston 66 returns to the initial position by the urging force of the coil spring 67. The change of the variable volume chamber 693, that is, the reciprocating movement of the piston 66 is facilitated by the replenishing liquid passage 19B communicating with the low pressure portion.

The relief circuit including the relief valve 730 provides the same effects as the fourth embodiment. Other functions and effects are the same as those of the third embodiment.

[Other Embodiments]
As mentioned above, although the form for implementing this invention was demonstrated based on drawing, the specific structure of this invention is not limited to embodiment, The design change etc. of the range which does not deviate from the summary of invention are included. Even if it exists, it is included in this invention. In addition, any combination or omission of each constituent element described in the claims and the specification is possible within a range where at least a part of the above-described problems can be solved or a range where at least a part of the effect is achieved. It is.

[Other aspects that can be grasped from the embodiment]
Other aspects that can be understood from the embodiment described above will be described below.
(1) The hydraulic control device, in one embodiment thereof,
A connecting fluid path for connecting a master cylinder that generates a brake fluid pressure in response to an operation of a brake pedal, and a wheel cylinder portion that can apply a braking force to a wheel portion in accordance with the brake fluid pressure;
A shut-off valve disposed in the connection liquid path;
A first hydraulic pressure source capable of supplying brake fluid to a portion of the connection fluid path located on the wheel cylinder portion side with respect to the shutoff valve;
A control unit capable of executing boost control for controlling the first hydraulic pressure source and the shut-off valve during operation of the brake pedal and supplying brake fluid to the wheel cylinder unit;
An on-off valve that is disposed in the connection liquid path and that operates in a closing direction when the brake pedal is operated in a state where the boost control is not operated;
Brake fluid can be supplied to a portion of the connection fluid path located on the wheel cylinder portion side with respect to the on-off valve, and when the brake pedal is operated in a state where the boost control is not activated. A second hydraulic pressure source operable.
(2) In a more preferred embodiment, in the above embodiment,
The on-off valve is disposed in the portion of the connection liquid path on the side located on the wheel cylinder portion with respect to the shutoff valve.
(3) In another preferred embodiment, in any of the above embodiments,
The second hydraulic pressure source can supply brake fluid only to a portion of the connection fluid path that is connected to the wheel cylinder portion corresponding to the front wheel of the wheel portion.
(4) In still another preferred embodiment, in any of the above embodiments,
A relief valve is provided in a fluid path connecting the low pressure portion and the discharge side of the second fluid pressure source, and can recirculate brake fluid to the low pressure portion.
(5) In still another preferred embodiment, in any of the above embodiments,
The on-off valve is disposed in a portion of the connection liquid path located on the master cylinder side with respect to the shutoff valve,
The second hydraulic pressure source can supply brake fluid to a portion of the connection fluid path between the on-off valve and the shutoff valve.
(6) In still another preferred embodiment, in any of the above embodiments,
A relief valve is provided in a fluid path connecting the low pressure portion and the discharge side of the second fluid pressure source, and can recirculate brake fluid to the low pressure portion.
(7) In still another preferred embodiment, in any of the above embodiments,
A bypass fluid path that connects the master cylinder and the portion of the connection fluid path that is located on the wheel cylinder portion side with respect to the on-off valve;
A piston that is disposed in the bypass fluid passage and is operable by a brake fluid pressure generated by the master cylinder, the brake fluid being closer to the wheel cylinder portion than the area receiving the brake fluid pressure on the master cylinder side And a piston having a smaller area for receiving pressure.
(8) From another point of view, the brake system is, in one embodiment thereof,
A master cylinder unit having a master cylinder that generates brake fluid pressure in response to operation of the brake pedal;
A first hydraulic unit capable of increasing the brake hydraulic pressure;
A second hydraulic pressure unit capable of increasing the brake hydraulic pressure,
The first hydraulic unit is
A first input port to which brake fluid is input;
A first connection liquid path connected to the first input port;
A shutoff valve disposed in the first connection liquid path;
A first output port connected to the first connection fluid path for outputting brake fluid;
A first hydraulic pressure source capable of discharging brake fluid to a portion of the first connection fluid path located closer to the first output port than the shutoff valve;
A control unit capable of executing a boost control for controlling the first hydraulic pressure source and the shutoff valve to generate a brake hydraulic pressure when the brake pedal is operated,
The second hydraulic unit is
A second input port to which brake fluid is input;
A second connection liquid path connected to the second input port;
An on-off valve disposed in the second connection liquid path and operating in a closing direction when the brake pedal is operated in a state where the boost control is not operating;
A second output port connected to the second connection fluid path for outputting brake fluid;
Brake fluid can be discharged to a portion of the second connection fluid path that is located closer to the second output port than the on-off valve, and the brake pedal of the brake pedal is not activated when the boost control is not activated. A second hydraulic pressure source operable during operation.
(9) In a more preferred embodiment, in the above embodiment,
The first input port is connected to the master cylinder;
The first output port is connected to the second input port;
The second output port is connected to a wheel cylinder portion that can apply a braking force to the wheel portion according to the brake fluid pressure.
(10) In another preferred embodiment, in any of the above embodiments,
The second hydraulic unit can supply brake fluid only to the wheel cylinder part corresponding to the front wheel of the wheel part.
(11) In still another preferred embodiment, in any of the above embodiments,
The second hydraulic pressure unit is a relief valve disposed in a liquid path connecting a low pressure portion and a discharge side of the second hydraulic pressure source, and includes a relief valve capable of returning brake fluid to the low pressure portion. .
(12) In still another preferred embodiment, in any of the above embodiments,
The second input port is connected to the master cylinder;
The second output port is connected to the first input port;
The first output port is connected to a wheel cylinder part capable of applying a braking force to the wheel part according to the brake fluid pressure.
(13) In still another preferred embodiment, in any of the above embodiments,
The second hydraulic pressure unit is a relief valve disposed in a liquid path connecting a low pressure portion and a discharge side of the second hydraulic pressure source, and includes a relief valve capable of returning brake fluid to the low pressure portion. .
(14) In still another preferred embodiment, in any of the above embodiments,
The second hydraulic unit is
A portion of the second connection liquid path that is positioned on the second input port side with respect to the on-off valve, and the second output port with respect to the on-off valve of the second connection liquid path. A portion located on the side of the bypass, a bypass liquid path connecting the
A piston disposed in the bypass fluid path and operable by a brake fluid pressure generated by the master cylinder, the second connection fluid path being closer to the second input port than the on-off valve; The area of the second connection fluid path that receives the brake fluid pressure of the part that is located on the second output port side with respect to the on-off valve, rather than the area that receives the brake fluid pressure of the part located. A smaller piston.
(15) In still another preferred embodiment, in any of the above embodiments,
The state where the boost control is not activated is detected by a controller on the vehicle side.
(16) In still another preferred embodiment, in any of the above embodiments,
The state where the boost control is not activated is detected by the failure detection unit of the first hydraulic pressure unit.
(17) From another point of view, the auxiliary hydraulic unit is, in one embodiment thereof,
When the brake pedal is operated, the main hydraulic unit that can execute the boost control that supplies the brake hydraulic pressure to the wheel cylinder portion of the wheel when the brake pedal is operated does not execute the boost control, and operates when the brake pedal is operated. Thus, the brake fluid pressure can be supplied to the wheel cylinder portion.
(18) In a more preferred embodiment, in the above embodiment,
A hydraulic pressure source capable of supplying brake fluid to the wheel cylinder portion;
A relief valve disposed in a fluid path connecting a low pressure portion and a discharge side of the fluid pressure source and capable of returning brake fluid to the low pressure portion.

This application claims priority based on Japanese Patent Application No. 2017-48091 filed on Mar. 14, 2017. The entire disclosure including the specification, claims, drawings and abstract of Japanese Patent Application No. 2017-48091 filed on Mar. 14, 2017 is incorporated herein by reference in its entirety.

1 Brake system, 100 Brake pedal, 1C Master cylinder unit, 3 Master cylinder, 1A 1st hydraulic unit, 11A 1st connecting fluid path, 41 1st input port, 42 1st output port, 71A shutoff valve, 81A 1st Pump (first hydraulic pressure source), 1B, second hydraulic pressure unit, 11B, second connecting fluid path, 61, second input port, 62, second output port, 71B on-off valve, 81B second pump (second hydraulic pressure source) , 90 Electronic control unit, 901 1st control unit, 902 2nd control unit

Claims

A hydraulic control device,
A connecting fluid path for connecting a master cylinder that generates a brake fluid pressure in response to an operation of a brake pedal, and a wheel cylinder portion that can apply a braking force to a wheel portion in accordance with the brake fluid pressure;
A shut-off valve disposed in the connection liquid path;
A first hydraulic pressure source capable of supplying brake fluid to a portion of the connection fluid path located on the wheel cylinder portion side with respect to the shutoff valve;
A control unit capable of executing boost control for controlling the first hydraulic pressure source and the shut-off valve during operation of the brake pedal and supplying brake fluid to the wheel cylinder unit;
An on-off valve that is disposed in the connection liquid path and that operates in a closing direction when the brake pedal is operated in a state where the boost control is not operated;
Brake fluid can be supplied to a portion of the connection fluid path located on the wheel cylinder portion side with respect to the on-off valve, and when the brake pedal is operated in a state where the boost control is not activated. A fluid pressure control device comprising: a second fluid pressure source operable.
The hydraulic control device according to claim 1,
The on-off valve is disposed in the portion of the connecting fluid path that is located on the wheel cylinder portion side with respect to the shutoff valve.
The hydraulic control device according to claim 2,
The second hydraulic pressure source can supply brake fluid only to a portion of the connection fluid path that is connected to the wheel cylinder portion corresponding to the front wheel of the wheel portion.
The hydraulic control device according to claim 3,
A hydraulic pressure control device including a relief valve that is disposed in a liquid path connecting a low pressure portion and a discharge side of the second hydraulic pressure source and capable of returning brake fluid to the low pressure portion.
The hydraulic control device according to claim 1,
The on-off valve is disposed in a portion of the connection liquid path located on the master cylinder side with respect to the shutoff valve,
The second hydraulic pressure source is capable of supplying brake fluid to a portion of the connection fluid path between the on-off valve and the shutoff valve.
The hydraulic control device according to claim 1,
A hydraulic pressure control device including a relief valve that is disposed in a liquid path connecting a low pressure portion and a discharge side of the second hydraulic pressure source and capable of returning brake fluid to the low pressure portion.
The hydraulic control device according to claim 1,
A bypass fluid path that connects the master cylinder and the portion of the connection fluid path that is located on the wheel cylinder portion side with respect to the on-off valve;
A piston that is disposed in the bypass fluid passage and is operable by a brake fluid pressure generated by the master cylinder, the brake fluid being closer to the wheel cylinder portion than the area receiving the brake fluid pressure on the master cylinder side A hydraulic control device comprising: a piston having a smaller area for receiving pressure.
A brake system,
A master cylinder unit having a master cylinder that generates brake fluid pressure in response to operation of the brake pedal;
A first hydraulic unit capable of increasing the brake hydraulic pressure;
A second hydraulic pressure unit capable of increasing the brake hydraulic pressure,
The first hydraulic unit is
A first input port to which brake fluid is input;
A first connection liquid path connected to the first input port;
A shutoff valve disposed in the first connection liquid path;
A first output port connected to the first connection fluid path for outputting brake fluid;
A first hydraulic pressure source capable of discharging brake fluid to a portion of the first connection fluid path located closer to the first output port than the shutoff valve;
A control unit capable of executing a boost control for controlling the first hydraulic pressure source and the shutoff valve to generate a brake hydraulic pressure when the brake pedal is operated,
The second hydraulic unit is
A second input port to which brake fluid is input;
A second connection liquid path connected to the second input port;
An on-off valve disposed in the second connection liquid path and operating in a closing direction when the brake pedal is operated in a state where the boost control is not operating;
A second output port connected to the second connection fluid path for outputting brake fluid;
Brake fluid can be discharged to a portion of the second connection fluid path that is located closer to the second output port than the on-off valve, and the brake pedal of the brake pedal is not activated when the boost control is not activated. A brake system comprising: a second hydraulic pressure source operable during operation.
The brake system according to claim 8, wherein
The first input port is connected to the master cylinder;
The first output port is connected to the second input port;
The second output port is connected to a wheel cylinder part capable of applying a braking force to a wheel part according to the brake fluid pressure.
The brake system according to claim 9,
The second hydraulic unit can supply brake fluid only to the wheel cylinder portion corresponding to the front wheel of the wheel portion.
The brake system according to claim 10, wherein
The second hydraulic pressure unit is a relief valve disposed in a liquid path connecting a low pressure portion and a discharge side of the second hydraulic pressure source, and includes a relief valve capable of returning brake fluid to the low pressure portion. Brake system.
The brake system according to claim 8, wherein
The second input port is connected to the master cylinder;
The second output port is connected to the first input port;
The first output port is connected to a wheel cylinder part capable of applying a braking force to a wheel part according to the brake fluid pressure.
The brake system according to claim 8, wherein
The second hydraulic pressure unit is a relief valve disposed in a liquid path connecting a low pressure portion and a discharge side of the second hydraulic pressure source, and includes a relief valve capable of returning brake fluid to the low pressure portion. Brake system.
The brake system according to claim 8, wherein
The second hydraulic unit is
A portion of the second connection liquid path that is positioned on the second input port side with respect to the on-off valve, and the second output port with respect to the on-off valve of the second connection liquid path. A portion located on the side of the bypass, a bypass liquid path connecting the
A piston disposed in the bypass fluid path and operable by a brake fluid pressure generated by the master cylinder, the second connection fluid path being closer to the second input port than the on-off valve; The area of the second connection fluid path that receives the brake fluid pressure of the part that is located on the second output port side with respect to the on-off valve, rather than the area that receives the brake fluid pressure of the part that is located. The smaller piston,
With brake system.
The brake system according to claim 8, wherein
A state in which the boost control is not activated is detected by a vehicle-side controller.
The brake system according to claim 8, wherein
A state in which the boost control is not activated is detected by a failure detection unit of the first hydraulic pressure unit.
An auxiliary hydraulic unit,
When the brake pedal is operated, the main hydraulic unit that can execute the boost control that supplies the brake hydraulic pressure to the wheel cylinder portion of the wheel when the brake pedal is operated does not execute the boost control, and operates when the brake pedal is operated. An auxiliary hydraulic pressure unit capable of supplying brake hydraulic pressure to the wheel cylinder.
The auxiliary hydraulic unit according to claim 17,
A hydraulic pressure source capable of supplying brake fluid to the wheel cylinder portion;
An auxiliary hydraulic unit comprising: a relief valve that is disposed in a liquid path that connects a low-pressure part and a discharge side of the hydraulic pressure source, and is capable of returning brake fluid to the low-pressure part.