WO2019131733A1 - Vehicle braking device - Google Patents

Abstract

The present invention is a vehicle braking device comprising an input piston 13 that advances in a prescribed direction inside a cylinder 11 in accordance with an increase in the stroke of a brake operation member 10, a master piston 14 that is disposed so as to be separated in the prescribed direction from the input piston 13 inside the cylinder 11, a drive unit 4 that drives the master piston 14 in the prescribed direction to thereby generate a master pressure, and a regenerative braking unit 8 that applies regenerative braking force to a vehicle wheel, the vehicle braking device controlling the regenerative braking unit 8 and the drive unit 4 in a coordinated manner while increasing the regenerative braking force in accordance with an increase in the stroke, wherein the vehicle braking device also comprises a control unit 61 that, when the stroke is equal to or greater than the prescribed value, executes an adjustment control to increase the drive amount of the master piston 14 by the drive unit 4 by a specified value and reduce the regenerative braking force in accordance with the specified value.

Description

Vehicle braking system

The present invention relates to a braking device for a vehicle.

In a vehicle braking apparatus including a regenerative braking unit that applies regenerative braking force to wheels, an input piston and an input piston that move forward in response to an operation of a brake operation member in a master cylinder in order to obtain regenerative energy as much as possible. A master piston spaced from the front is disposed. This separation distance prevents the master piston from directly advancing by normal operation of the brake operation member, and controls the drive of the master piston electrically by another drive source while generating the maximum regenerative braking force. can do. Such a configuration is disclosed, for example, in Japanese Patent Application Laid-Open No. 2012-214091.

Unexamined-Japanese-Patent No. 2012-214091

In the above-described configuration, the input piston and the master piston are designed to be in minimal contact with each other when the stroke of the brake operation member is increased, so that the brake feeling is not deteriorated. Here, in a situation where the required braking force is satisfied only with the regenerative braking force, the master piston does not move forward, so both pistons approach each other by the stroke of the brake operation member. For example, if a sudden operation (a sudden depression) is further performed in this situation, there is a risk that both pistons abut. In order to avoid this, for example, it is conceivable to enlarge the master cylinder and to increase the separation distance. However, this increases the size of the entire apparatus. On the other hand, the vehicle brake system needs to exhibit appropriate braking performance, that is, a braking force (and more preferably, vehicle stability) according to the operation amount of the brake operation member (the required braking force).

The present invention has been made in view of such circumstances, and it is possible to suppress the contact between the input piston and the master piston without increasing the size of the device, and to provide an appropriate braking performance. It is an object of the present invention to provide a braking device.

The vehicle braking system according to the present invention is disposed at an input piston which moves in a predetermined direction in the cylinder according to an increase in the stroke of the brake operating member, and spaced apart from the input piston in the cylinder in the predetermined direction. A master piston, a drive unit generating a master pressure corresponding to a fluid pressure braking force applied to the wheel by driving the master piston in the predetermined direction, and a regenerative braking unit applying regenerative braking force to the wheel And the regenerative braking force of the regenerative braking unit is increased according to the increase of the stroke, and the vehicle braking device for cooperatively controlling the regenerative braking unit and the drive unit, wherein the stroke is a predetermined value. When it becomes more than the value, the drive amount of the master piston is increased by the specified value by the drive part, and the regenerative braking force is generated by the regenerative braking part according to the specified value. A control unit for executing adjustment control to decrease.

According to the present invention, when the stroke becomes equal to or greater than the predetermined value, the adjustment control causes the master piston to be driven in the predetermined direction, that is, in the direction away from the input piston. Thereby, the contact between the input piston and the master piston is suppressed. Also, although the hydraulic braking force is also increased by the increase of the master pressure due to the progress of the master piston in the predetermined direction, the regenerative braking force is reduced, so the braking force does not become too large and the braking force according to the required braking force can be exerted It becomes. In addition, although a configuration in which a regenerative braking unit is provided for the front wheel or rear wheel and the master pressure corresponds to the hydraulic braking force for both front and rear wheels is generally used as a vehicle braking device, also in this configuration, the regenerative braking force is By reducing the braking force of one of the front wheels and the rear wheels from becoming excessively larger than the other, it is possible to exhibit appropriate vehicle stability.

It is a block diagram of the braking device for vehicles of a 1st embodiment. It is a block diagram of the actuator of a 1st embodiment. It is a time chart which shows an example of adjustment control of a 1st embodiment. It is an explanatory view showing braking power distribution of a 1st embodiment. It is an explanatory view showing the relation between the degree of deceleration of a 1st embodiment, and the amount of regeneration. It is a time chart which shows another example of adjustment control of a 1st embodiment. It is a block diagram of the control apparatus of 2nd Embodiment.

Hereinafter, an embodiment of the present invention will be described based on the drawings. Each figure used for explanation is a conceptual diagram, and the shape of each part may not necessarily be exact.
First Embodiment
As shown in FIGS. 1 and 2, the vehicle braking device BF includes a master cylinder 1, a reaction force generator 2, a first control valve 22, a second control valve 23, and a servo pressure generator (“drive Section 4), an actuator 5, wheel cylinders 541 to 544, various sensors 71 to 77, an upstream ECU 6, and a downstream ECU 6A.

In addition, since the vehicle of the first embodiment is a hybrid vehicle, the vehicle braking device BF generates regenerative braking force on the wheels W to execute cooperative control with the actuator 5 ("Regenerative braking portion 8) is provided. The regenerative braking device 8 is provided for the rear wheel Wr, and includes a hybrid ECU 81, a generator 82, an inverter 83, and a battery 84. The details of the regenerative braking device 8 are omitted because they are known. The vehicle of the first embodiment is a rear wheel drive vehicle. In the description, the wheels Wfl, Wfr, Wrl, Wrr may be described as the wheel W, the front wheels Wfl, Wfr as the front wheel Wf, and the rear wheels Wrl, Wrr as the rear wheel Wr. On each wheel W, for example, a brake pad Z1 and a brake rotor Z2 are installed.

The master cylinder 1 is a part that supplies the brake fluid to the actuator 5 in accordance with the amount of operation of the brake pedal (corresponding to the "brake operation member") 10, and the main cylinder 11, the cover cylinder 12, the input piston 13, the first A master piston 14 and a second master piston 15 are provided. The brake pedal 10 may be any brake operating means that allows the driver to brake.

The main cylinder 11 is a bottomed, substantially cylindrical housing that is closed at the front and opens at the rear. An inner wall portion 111 that protrudes in an inward flange shape is provided on the inner peripheral side of the main cylinder 11 so as to be closer to the rear. The center of the inner wall portion 111 is a through hole 111 a penetrating in the front-rear direction. Further, on the front side of the inner wall portion 111 inside the main cylinder 11, small diameter portions 112 (rear) and 113 (front) whose inner diameters are slightly smaller are provided. That is, the small diameter portions 112 and 113 protrude in an annular shape inwardly from the inner peripheral surface of the main cylinder 11. Inside the main cylinder 11, a first master piston 14 is disposed slidably in the small diameter portion 112 so as to be movable in the axial direction. Similarly, the second master piston 15 is disposed slidably in the small diameter portion 113 so as to be movable in the axial direction.

The cover cylinder 12 includes a substantially cylindrical cylinder portion 121, a bellows cylindrical boot 122, and a cup-shaped compression spring 123. The cylinder portion 121 is disposed on the rear end side of the main cylinder 11 and coaxially fitted in an opening on the rear side of the main cylinder 11. The inner diameter of the front portion 121 a of the cylinder portion 121 is larger than the inner diameter of the through hole 111 a of the inner wall portion 111. Further, the inner diameter of the rear portion 121b of the cylinder portion 121 is smaller than the inner diameter of the front portion 121a.

The dustproof boot 122 has a bellows-like cylindrical shape and can be expanded and contracted in the front-rear direction, and is assembled so as to contact the rear end side opening of the cylinder portion 121 on the front side thereof. A through hole 122 a is formed at the rear center of the boot 122. The compression spring 123 is a coil-like biasing member disposed around the boot 122, and the front side is in contact with the rear end of the main cylinder 11, and the rear side is compressed so as to approach the through hole 122a of the boot 122. It is diameter. The rear end of the boot 122 and the rear end of the compression spring 123 are coupled to the operating rod 10a. The compression spring 123 biases the operating rod 10 a rearward.

The input piston 13 is a piston that slides in the cover cylinder 12 in response to the operation of the brake pedal 10. The input piston 13 is a bottomed substantially cylindrical piston having a bottom in the front and an opening in the rear. The bottom wall 131 constituting the bottom surface of the input piston 13 is larger in diameter than the other portions of the input piston 13. The input piston 13 is axially slidably and fluidly disposed in the rear portion 121 b of the cylinder portion 121, and the bottom wall 131 enters the inner peripheral side of the front portion 121 a of the cylinder portion 121.

Inside the input piston 13, an operation rod 10 a interlocking with the brake pedal 10 is disposed. The pivot 10b at the tip of the operating rod 10a can push the input piston 13 forward. The rear end of the operating rod 10 a protrudes to the outside through the opening on the rear side of the input piston 13 and the through hole 122 a of the boot 122 and is connected to the brake pedal 10. When the brake pedal 10 is depressed, the operating rod 10a advances while pressing the boot 122 and the compression spring 123 in the axial direction. As the operation rod 10a advances, the input piston 13 also advances in conjunction with it.

The first master piston 14 is disposed slidably on the inner wall portion 111 of the main cylinder 11 in the axial direction. The pressure cylinder part 141, the flange part 142, and the protrusion part 143 are integrally formed in the 1st master piston 14 in order from the front side. The pressure cylinder portion 141 is formed in a substantially cylindrical shape with a bottom at the front and has an opening, has a gap with the inner circumferential surface of the main cylinder 11, and is in sliding contact with the small diameter portion 112. A biasing member 144 in the form of a coil spring is disposed between the second master piston 15 and the internal space of the pressure cylinder portion 141. The first master piston 14 is biased rearward by the biasing member 144. In other words, the first master piston 14 is biased by the biasing member 144 toward the set initial position.

The flange portion 142 has a diameter larger than that of the pressure cylinder portion 141 and is in sliding contact with the inner peripheral surface of the main cylinder 11. The projecting portion 143 has a diameter smaller than that of the flange portion 142 and is disposed so as to slide in a fluid-tight manner in the through hole 111 a of the inner wall portion 111. The rear end of the protruding portion 143 passes through the through hole 111 a and protrudes into the internal space of the cylinder portion 121, and is separated from the inner circumferential surface of the cylinder portion 121. The rear end surface of the projecting portion 143 is separated from the bottom wall 131 of the input piston 13, and the separation distance d is configured to be variable. Thus, in the initial state, the first master piston 14 is disposed in front of the input piston 13 so as to be separated from the input piston 13 by the separation distance d.

Here, a “first master chamber 1D” is defined by the inner circumferential surface of the main cylinder 11, the front side of the pressure cylinder portion 141 of the first master piston 14, and the rear side of the second master piston 15. Further, the rear chamber behind the first master chamber 1D is defined by the inner peripheral surface (inner peripheral portion) of the main cylinder 11, the small diameter portion 112, the front surface of the inner wall portion 111, and the outer peripheral surface of the first master piston 14. ing. The front end portion and the rear end portion of the flange portion 142 of the first master piston 14 divide the rear chamber back and forth, the "second hydraulic pressure chamber 1C" is partitioned on the front side, and the "servo chamber 1A" is positioned on the rear side. It is divided. The volume of the second hydraulic pressure chamber 1C decreases as the first master piston 14 advances, and the volume increases as the first master piston 14 retreats. Further, the inner peripheral portion of the main cylinder 11, the rear surface of the inner wall portion 111, the inner peripheral surface (inner peripheral portion) of the front portion 121a of the cylinder portion 121, the projecting portion 143 (rear end portion) of the first master piston 14, and the input The “first fluid pressure chamber 1 </ b> B” is defined by the front end portion of the piston 13.

The second master piston 15 is disposed on the front side of the first master piston 14 in the main cylinder 11 so as to be axially movable and in sliding contact with the small diameter portion 113. The second master piston 15 is integrally formed with a cylindrical pressure cylinder 151 having an opening at the front, and a bottom wall 152 closing the rear side of the pressure cylinder 151. The bottom wall 152 supports the biasing member 144 between itself and the first master piston 14. A biasing member 153 in the form of a coil spring is disposed in the internal space of the pressure cylinder 151 and between the closed inner bottom surface 111 d of the main cylinder 11. The second master piston 15 is biased rearward by the biasing member 153. In other words, the second master piston 15 is biased by the biasing member 153 toward the set initial position. A “second master chamber 1E” is defined by the inner peripheral surface of the main cylinder 11, the inner bottom surface 111d, and the second master piston 15.

The master cylinder 1 is formed with ports 11a to 11i that communicate the inside with the outside. The port 11 a is formed rearward of the inner wall portion 111 of the main cylinder 11. The port 11 b is formed at the same position in the axial direction as the port 11 a, facing the port 11 a. The port 11 a and the port 11 b communicate with each other through an annular space between the inner peripheral surface of the main cylinder 11 and the outer peripheral surface of the cylinder portion 121. The port 11 a and the port 11 b are connected to the pipe 161 and connected to the reservoir 171 (low pressure source).

The port 11 b is in communication with the first fluid pressure chamber 1 B by a passage 18 formed in the cylinder portion 121 and the input piston 13. The passage 18 is shut off when the input piston 13 advances, whereby the first hydraulic pressure chamber 1B and the reservoir 171 are shut off. The port 11c is formed rearward of the inner wall portion 111 and forward of the port 11a, and communicates the first fluid pressure chamber 1B with the pipe 162. The port 11d is formed forward of the port 11c, and communicates the servo chamber 1A with the pipe 163. The port 11e is formed forward of the port 11d, and communicates the second hydraulic pressure chamber 1C with the pipe 164.

The port 11 f is formed between the seal members G 1 and G 2 of the small diameter portion 112, and communicates the reservoir 172 with the inside of the main cylinder 11. The port 11 f is in communication with the first master chamber 1 D via a passage 145 formed in the first master piston 14. The passage 145 is formed at a position where the port 11 f and the first master chamber 1 D are shut off when the first master piston 14 advances. The port 11g is formed in front of the port 11f, and communicates the first master chamber 1D with the conduit 31.

The port 11 h is formed between the seal members G 3 and G 4 of the small diameter portion 113, and communicates the reservoir 173 with the inside of the main cylinder 11. The port 11 h is in communication with the second master chamber 1 E via a passage 154 formed in the pressure cylinder 151 of the second master piston 15. The passage 154 is formed at a position where the port 11 h and the second master chamber 1 E are shut off when the second master piston 15 advances. The port 11i is formed in front of the port 11h, and communicates the second master chamber 1E with the conduit 32.

Further, in the master cylinder 1, a seal member such as an O-ring is appropriately disposed. The seal members G1 and G2 are disposed at the small diameter portion 112, and are in fluid-tight contact with the outer peripheral surface of the first master piston. Similarly, the seal members G3 and G4 are disposed at the small diameter portion 113, and abut on the outer peripheral surface of the second master piston 15 in a fluid tight manner. Also, seal members G5 and G6 are disposed between the input piston 13 and the cylinder portion 121.

The stroke sensor 71 is a sensor that detects an operation amount (stroke) at which the brake pedal 10 is operated by the driver, and transmits a detection signal to the upstream ECU 6 and the downstream ECU 6A. The brake stop switch 72 is a switch that detects the presence or absence of the operation of the brake pedal 10 by the driver as a binary signal, and transmits a detection signal to the upstream ECU 6.

The reaction force generating device 2 is a device that generates a reaction force that opposes the operating force when the brake pedal 10 is operated, and is mainly configured of the stroke simulator 21. In response to the operation of the brake pedal 10, the stroke simulator 21 generates a reaction fluid pressure in the first fluid pressure chamber 1B and the second fluid pressure chamber 1C. The stroke simulator 21 is configured by slidably fitting a piston 212 to a cylinder 211. The piston 212 is biased rearward by a compression spring 213, and a reaction fluid pressure chamber 214 is formed on the rear side of the piston 212. The reaction force fluid pressure chamber 214 is connected to the second fluid pressure chamber 1C via the pipe 164 and the port 11e, and the reaction force fluid pressure chamber 214 is connected via the pipe 164 to the first control valve 22 and the second control. It is connected to the valve 23.

The first control valve 22 is an electromagnetic valve that is closed in a non-energized state, and is controlled by the upstream ECU 6 to open and close. The first control valve 22 is connected between the pipe 164 and the pipe 162. Here, the pipe 164 communicates with the second fluid pressure chamber 1C via the port 11e, and the pipe 162 communicates with the first fluid pressure chamber 1B via the port 11c. When the first control valve 22 is opened, the first fluid pressure chamber 1B is opened, and when the first control valve 22 is closed, the first fluid pressure chamber 1B is closed. Therefore, the pipe 164 and the pipe 162 are provided to communicate the first fluid pressure chamber 1B with the second fluid pressure chamber 1C.

The first control valve 22 is closed in a non-energized state without being energized, and at this time, the first fluid pressure chamber 1B and the second fluid pressure chamber 1C are shut off. As a result, the first fluid pressure chamber 1B is sealed and there is no place to go for the brake fluid, and the input piston 13 and the first master piston 14 are interlocked while maintaining a fixed separation distance. Further, the first control valve 22 is open in the energized state, and at this time, the first fluid pressure chamber 1B and the second fluid pressure chamber 1C are communicated with each other. As a result, the volume change of the first fluid pressure chamber 1B and the second fluid pressure chamber 1C accompanying the advancing and retracting of the first master piston 14 is absorbed by the movement of the brake fluid.

The pressure sensor 73 is a sensor that detects the reaction fluid pressure in the second fluid pressure chamber 1C and the first fluid pressure chamber 1B, and is connected to the pipe 164. The pressure sensor 73 detects the pressure in the second hydraulic pressure chamber 1C when the first control valve 22 is closed, and communicates with the first hydraulic pressure chamber 1B when the first control valve 22 is open. Pressure will also be detected. The pressure sensor 73 transmits a detection signal to the upstream ECU 6.

The second control valve 23 is an electromagnetic valve that opens in a non-energized state, and the upstream side ECU 6 controls the opening and closing of the second control valve 23. The second control valve 23 is connected between the pipe 164 and the pipe 161. Here, the pipe 164 communicates with the second fluid pressure chamber 1C via the port 11e, and the pipe 161 communicates with the reservoir 171 via the port 11a. Therefore, the second control valve 23 communicates between the second hydraulic pressure chamber 1C and the reservoir 171 in a non-energized state to generate a reaction liquid pressure, but shuts off in a energized state to generate a reaction liquid pressure. Let

The servo pressure generator 4 is a so-called hydraulic booster (booster), and includes a pressure reducing valve 41, a pressure increasing valve 42, a pressure supply unit 43, and a regulator 44. The pressure reducing valve 41 is a normally open solenoid valve (normally open valve) that opens in a non-energized state, and the flow rate (or pressure) is controlled by the upstream ECU 6. One end of the pressure reducing valve 41 is connected to the pipe 161 via the pipe 411, and the other end of the pressure reducing valve 41 is connected to the pipe 413. That is, one end of the pressure reducing valve 41 communicates with the reservoir 171 via the pipes 411 and 161 and the ports 11a and 11b. The pressure reducing valve 41 is closed to prevent the brake fluid from flowing out of the pilot chamber 4D. The reservoir 171 and the reservoir 434 are in communication although not shown. The reservoir 171 and the reservoir 434 may be the same reservoir.

The pressure increasing valve 42 is a normally closed electromagnetic valve (normally closed valve) closed in a non-energized state, and the flow rate (or pressure) is controlled by the upstream ECU 6. One end of the pressure increase valve 42 is connected to the pipe 421, and the other end of the pressure increase valve 42 is connected to the pipe 422. The pressure supply unit 43 is a part that mainly supplies a high pressure hydraulic fluid to the regulator 44. The pressure supply unit 43 includes an accumulator 431, a hydraulic pump 432, a motor 433, and a reservoir 434. The pressure sensor 75 detects the hydraulic pressure of the accumulator 431. The configuration of the pressure supply unit 43 is known, and therefore the description thereof is omitted.

The regulator 44 is a mechanical regulator and has a pilot chamber 4D formed therein. Further, the regulator 44 is provided with a plurality of ports 4a to 4h. The pilot chamber 4D is connected to the pressure reducing valve 41 via the port 4f and the pipe 413, and is connected to the pressure increasing valve 42 via the port 4g and the pipe 421. By opening the pressure increasing valve 42, high pressure brake fluid is supplied from the accumulator 431 to the pilot chamber 4D via the ports 4a, 4b and 4g, the piston moves, and the pilot chamber 4D is expanded. The valve member moves according to the enlargement, the port 4 a and the port 4 c communicate with each other, and high pressure brake fluid is supplied to the servo chamber 1 A through the pipe 163. On the other hand, when the pressure reducing valve 41 is opened, the fluid pressure (pilot pressure) in the pilot chamber 4D is reduced, and the flow passage between the port 4a and the port 4c is shut off by the valve member. As described above, the upstream ECU 6 controls the pilot pressure corresponding to the servo pressure by controlling the pressure reducing valve 41 and the pressure increasing valve 42 to control the servo pressure. The actual servo pressure is detected by the pressure sensor 74. The first embodiment has a by-wire configuration in which the brake operation mechanism and the pressure control mechanism are separated.

The actuator 5 is disposed between the first master chamber 1D and the second master chamber 1E in which the master pressure is generated, and the wheel cylinders 541 to 544. The actuator 5 and the first master chamber 1D are connected by a pipe line 31, and the actuator 5 and the second master chamber 1E are connected by a pipe line 32. The actuator 5 is a device that adjusts the fluid pressure (wheel pressure) of the wheel cylinders 541 to 544 in accordance with an instruction from the downstream ECU 6A. The actuator 5 executes pressurization control, pressure increase control, pressure reduction control, or holding control that further pressurizes the brake fluid from the master pressure in accordance with a command from the downstream side ECU 6A. The actuator 5 combines these controls based on the command of the downstream side ECU 6A to execute anti-skid control (ABS control) or anti-slip control (ESC control).

Specifically, as shown in FIG. 3, the actuator 5 includes a hydraulic circuit 5A and a motor 90. The hydraulic circuit 5A includes a first piping system 50a and a second piping system 50b. The first piping system 50a is a system that controls the hydraulic pressure (wheel pressure) applied to the front wheels Wfl and Wfr. The second piping system 50b is a system that controls the hydraulic pressure (wheel pressure) applied to the rear wheels Wrl, Wrr. Further, for each wheel W, a wheel speed sensor 76 is installed. In the first embodiment, front and rear piping is employed.

The first piping system 50a includes a main pipe A, a differential pressure control valve 51, pressure increasing valves 52, 53, pressure reducing lines B, pressure reducing valves 54, 55, a pressure control reservoir 56, a reflux line C, and the like. , An auxiliary conduit D, an orifice portion 58, and a damper portion 59. In the description, the term "line" can be replaced with, for example, a hydraulic line, a flow path, an oil path, a passage, or a pipe.

The main pipeline A is a pipeline connecting the pipeline 32 and the wheel cylinders 541 and 542. The differential pressure control valve 51 is an electromagnetic valve which is provided in the main conduit A and controls the main conduit A to a communication state and a differential pressure state. The differential pressure state is a state in which the flow path is restricted by the valve, and can also be referred to as a throttle state. The differential pressure control valve 51 controls the differential pressure between the fluid pressure on the master cylinder 1 side and the fluid pressure on the wheel cylinders 541 and 542 centering on the control current based on the instruction of the downstream side ECU 6A. In other words, according to the control current, the differential pressure control valve 51 measures the differential pressure between the hydraulic pressure of the portion on the master cylinder 1 side of the main conduit A and the hydraulic pressure of the portion on the wheel cylinders 541, 542 of the main conduit A. It is configured to be controllable.

The differential pressure control valve 51 is a normally open type that is in the communication state in the non-energized state. As the control current applied to the differential pressure control valve 51 increases, the differential pressure increases. When the differential pressure control valve 51 is controlled to a differential pressure state and the pump 57 is driven, the fluid pressure on the wheel cylinders 541 and 542 becomes larger than the fluid pressure on the master cylinder 1 side according to the control current . A check valve 51 a is provided for the differential pressure control valve 51. The main pipeline A branches into two pipelines A1 and A2 at a branch point X on the downstream side of the differential pressure control valve 51 so as to correspond to the wheel cylinders 541 and 542.

The pressure-increasing valves 52 and 53 are electromagnetic valves that open and close according to an instruction from the downstream side ECU 6A, and are normally open type electromagnetic valves that are opened (communicated state) in the non-energized state. The pressure intensifying valve 52 is disposed in the line A1, and the pressure intensifying valve 53 is disposed in the line A2. The pressure increase valves 52 and 53 are opened in the non-energized state at the time of pressure increase control and communicated with the wheel cylinders 541 to 544 and the branch point X, are energized at the time of holding control and pressure reduction control and are closed. And branch point X are cut off.

The pressure reducing line B connects between the pressure increasing valve 52 and the wheel cylinders 541 and 542 in the line A1 and the pressure control reservoir 56, and adjusts pressure between the pressure increasing valve 53 and the wheel cylinders 541 and 542 in the line A2. It is a conduit connecting the pressure reservoir 56. The pressure reducing valves 54 and 55 are solenoid valves that open and close according to an instruction of the downstream side ECU 6A, and are normally closed type solenoid valves that are closed (cut off) in a non-energized state. The pressure reducing valve 54 is disposed in the pressure reducing channel B on the wheel cylinders 541 and 542 side. The pressure reducing valve 55 is disposed in the pressure reducing channel B on the wheel cylinders 541 and 542 side. The pressure reducing valves 54 and 55 are energized mainly at the time of pressure reducing control to be in an open state, and allow the wheel cylinders 541 and 542 to communicate with the pressure regulating reservoir 56 via the pressure reducing pipeline B. The pressure control reservoir 56 is a reservoir having a cylinder, a piston, and a biasing member.

The reflux line C is a line connecting the pressure reducing line B (or pressure regulating reservoir 56) and the differential pressure control valve 51 and the pressure increasing valves 52 and 53 in the main line A (here, the branch point X). is there. The pump 57 is provided in the reflux line C so that the discharge port is disposed at the branch point X side and the suction port is disposed at the pressure control reservoir 56 side. The pump 57 is a gear-type electric pump (gear pump) driven by the motor 90. The pump 57 causes the brake fluid to flow from the pressure control reservoir 56 to the master cylinder 1 side or the wheel cylinders 541 and 542 side via the reflux line C. Further, the pump 57 pumps the brake fluid in the wheel cylinders 541 and 542 back to the master cylinder 1 via the pressure reducing valves 54 and 55 in an open state, for example, in anti-skid control. As described above, the pump 57 is disposed between the master cylinder 1 and the wheel cylinders 541 and 542, and can discharge the brake fluid in the wheel cylinders 541 and 542 to the outside of the wheel cylinders 541 and 542.

The pump 57 is configured to repeat a discharge process of discharging the brake fluid and a suction process of sucking the brake fluid. That is, when the pump 57 is driven by the motor 90, the discharge process and the suction process are alternately repeated. In the discharge process, the brake fluid sucked from the pressure control reservoir 56 in the suction process is supplied to the branch point X. The motor 90 is energized and driven through a relay (not shown) according to an instruction of the downstream side ECU 6A. The pump 57 and the motor 90 can be collectively referred to as an electric pump.

The orifice portion 58 is a throttle-shaped portion (so-called orifice) provided at a portion of the reflux line C between the pump 57 and the branch point X. The damper portion 59 is a damper (damper mechanism) connected to a portion of the return flow line C between the pump 57 and the orifice portion 58. The damper portion 59 absorbs and discharges the brake fluid in accordance with the pulsation of the brake fluid in the return conduit C. The orifice portion 58 and the damper portion 59 can be said to be a pulsation reducing mechanism that reduces (attenuates, absorbs) pulsation.

The auxiliary pipe line D is a pipe line connecting the pressure control hole 56 a of the pressure control reservoir 56 and the upstream side (or the master cylinder 1) of the main pipe line A with respect to the differential pressure control valve 51. The pressure control reservoir 56 is configured such that the valve hole 56b is closed as the inflow of the brake fluid to the pressure control hole 56a increases due to the increase in the stroke. A reservoir chamber 56c is formed on the side of the conduits B and C of the valve hole 56b.

When the pump 57 is driven, the brake fluid in the pressure control reservoir 56 or the master cylinder 1 is transferred to the portion between the differential pressure control valve 51 and the pressure increasing valves 52, 53 in the main conduit A via the reflux conduit C (branch point X Is discharged. Then, the wheel pressure is increased in accordance with the control states of the differential pressure control valve 51 and the pressure increasing valves 52, 53. As described above, in the actuator 5, pressurization control is executed by driving the pump 57 and controlling various valves. That is, the actuator 5 is configured to be able to press the wheel pressure. In the portion between the differential pressure control valve 51 of the main conduit A and the master cylinder 1, a pressure sensor 77 for detecting the fluid pressure (master pressure) of the portion is installed. The pressure sensor 77 transmits the detection result to the upstream ECU 6 and the downstream ECU 6A.

The second piping system 50b has a configuration similar to that of the first piping system 50a, and is a system that adjusts the hydraulic pressure of the wheel cylinders 543 and 544 of the rear wheels Wrl and Wrr. The second pipe system 50b corresponds to the main pipe A and connects the pipe 31 and the wheel cylinders 543 and 544, the differential pressure control valve 91 corresponding to the differential pressure control valve 51, and the pressure increasing valve 52. Pressure increasing valves 92 and 93 corresponding to the pressure control valve 53, pressure reducing conduits Bb corresponding to the pressure reducing flow passage B, pressure reducing valves 94 and 95 corresponding to the pressure reducing valves 54 and 55, pressure regulating reservoir 96 corresponding to the pressure regulating reservoir 56 , A reflux pipe Cb corresponding to the reflux pipe C, a pump 97 corresponding to the pump 57, an auxiliary pipe Db corresponding to the auxiliary pipe D, an orifice portion 58a corresponding to the orifice portion 58, and a damper portion And a damper portion 59a corresponding to 59. About the detailed composition of the 2nd piping system 50b, since explanation of the 1st piping system 50a can be referred to, explanation is omitted. Moreover, in the following description, the description of each part of the actuator 5 uses the code | symbol of 1st piping system 50a, and abbreviate | omits the code | symbol of 2nd piping system 50b.

The upstream ECU 6 and the downstream ECU 6A are an electronic control unit (ECU) including a CPU, a memory, and the like. The upstream ECU 6 is an ECU that executes control on the servo pressure generator 4 based on a target wheel pressure (or target deceleration) that is a target value of the wheel pressure. The upstream ECU 6 executes pressure increase control (pressurization control), pressure reduction control, or holding control with respect to the servo pressure generator 4 based on the target wheel pressure. In the pressure increase control, the pressure increase valve 42 is opened, and the pressure reduction valve 41 is closed. In the pressure reducing control, the pressure increasing valve 42 is closed, and the pressure reducing valve 41 is opened. In the holding control, the pressure increasing valve 42 and the pressure reducing valve 41 are closed.

Various sensors 71 to 77 are connected to the upstream ECU 6. The upstream ECU 6 obtains stroke information, master pressure information, reaction force hydraulic pressure information, servo pressure information, and wheel speed information from these sensors. The sensor and the upstream ECU 6 are connected by a communication line (CAN) not shown. Further, the upstream ECU 6 acquires information (during antiskid control, etc.) regarding the control state of the actuator 5 from the downstream ECU 6A.

The downstream ECU 6A is an ECU that executes control on the actuator 5 based on a target wheel pressure (or target deceleration) which is a target value of the wheel pressure. The downstream ECU 6A executes pressure increase control, pressure decrease control, holding control, or pressure control on the actuator 5 based on the target wheel pressure. The downstream ECU 6A acquires information from the various sensors 71 to 77 via the upstream ECU 6 or directly. The upstream ECU 6 and the downstream ECU 6A may be configured by one ECU.

Here, each control state by the downstream side ECU 6A will be briefly described taking control of the wheel cylinder 541 as an example. In pressure increase control, the pressure increase valve 52 (and the differential pressure control valve 51) is opened, and the pressure reduction valve 54 is closed. It becomes a state. The flow of the brake fluid from the upstream to the downstream is permitted by the check valve 51a installed in parallel with the differential pressure control valve 51, and the reverse is prohibited. Therefore, when the fluid pressure on the upstream side is higher than the fluid pressure on the downstream side, the brake fluid is supplied downstream via the check valve 51a without control to the differential pressure control valve 51. In the pressure reduction control, the pressure increasing valve 52 is closed, and the pressure reducing valve 54 is opened. In the holding control, the pressure increasing valve 52 and the pressure reducing valve 54 are closed. The holding control can also be performed by closing the pressure reducing valve 54 and closing (throttling) the differential pressure control valve 51 without closing the pressure increasing valve 52. Further, in the holding control, control is also performed to maintain the differential pressure while leaking the brake fluid from the differential pressure control valve 51 to the upstream side while driving the motor 90 and the pump 57 from the viewpoint of pressure response. That is, the differential pressure control valve 51 and / or the pressure increasing valve 52 correspond to a holding valve that holds the wheel pressure. In the pressurization control, the differential pressure control valve 51 is in the differential pressure state (throttling state), the pressure increasing valve 52 is opened, the pressure reducing valve 54 is closed, and the motor 90 and the pump 57 are driven.

The upstream ECU 6 sets the target deceleration (target value of deceleration) based on the stroke information, and the target deceleration information is determined downstream via the communication line. Transmit to the side ECU 6A. The target master pressure and the target wheel pressure are determined based on the target deceleration. The upstream ECU 6 and the downstream ECU 6A control the hydraulic pressure of the brake fluid so that the wheel pressure approaches the target wheel pressure (deceleration approaches the target deceleration) by cooperative control. The upstream ECU 6 calculates the target deceleration based on the stroke to calculate the target master pressure, and the downstream ECU 6A calculates the target wheel pressure based on the target deceleration, and the detected master pressure (or target master pressure) and the target The pressure amount (control amount) is set based on the wheel pressure.

Further, both the ECUs 6 and 6A execute cooperative control (regenerative cooperative control) with the hybrid ECU 81. In the regenerative coordinated control, for example, from the start of the brake operation to a predetermined situation, the target deceleration is achieved by the regenerative braking force by the regenerative braking device 8 and the pressurization of the wheel pressure by the actuator 5 (hydraulic braking force). Then, after the predetermined condition, pressurization of the master pressure by the servo pressure generator 4 is added as the hydraulic pressure braking force, and the target deceleration is achieved together with the regenerative braking force. In the vicinity of the end of the brake operation, for example, the target deceleration is achieved only by the regenerative braking force, and thereafter, the switching control to switch the regenerative braking force to the hydraulic braking force (pressurization by the actuator 5) is executed at a predetermined timing. The hybrid ECU 81 sets the target regenerative braking force according to the situation and transmits information of the actually generated regenerative braking force to both ECUs 6 and 6A, and both ECUs 6 and 6A request by regenerative braking force and hydraulic braking force. The servo pressure generator 4 and the actuator 5 are controlled such that the braking force (the required deceleration) is achieved.

As described above, the vehicle braking device BF is disposed to be separated forward from the input piston 13 in the main cylinder 11 and the input piston 13 which advances in the main cylinder 11 according to the increase in the stroke of the brake pedal 10. The servo pressure generator 4 generates a master pressure corresponding to the fluid pressure braking force applied to the wheel W by driving the first master piston 14 and the first master piston 14 forward, and the wheel W is regenerated. And a device for cooperatively controlling the regenerative braking device 8 and the servo pressure generator 4 while increasing the regenerative braking force of the regenerative braking device 8 according to the increase of the stroke. is there. Further, the regenerative braking device 8 applies regenerative braking force to the front wheel Wf or the rear wheel Wr of the wheels W, and the servo pressure generator 4 applies the hydraulic pressure (wheel pressure) based on the master pressure to the front wheel Wf and the rear wheel. A hydraulic braking force is applied to the wheel Wr.

(Adjustment control)
Here, adjustment control for suppressing the contact (collision) between the input piston 13 and the first master piston 14 and exhibiting an appropriate braking performance will be described. Here, it can be said that the respective ECUs 6, 6A, 81 constitute one control device 60 in order to execute the control in a coordinated manner. As a function, when the stroke of the brake pedal 10 becomes a predetermined value or more, the control device 60 increases the drive amount of the first master piston 14 by the servo pressure generator 4 by a prescribed value (predetermined drive amount) and the prescribed value The control unit 61 executes adjustment control to reduce the regenerative braking force by the regenerative braking device 8 according to the above.

The adjustment control can also be said to be control for decreasing the regenerative braking force by a predetermined amount with a decreasing gradient corresponding to the predetermined increasing gradient while increasing the servo pressure by the predetermined increasing gradient. The predetermined increase gradient is set to a constant value or a value corresponding to the increase gradient of the stroke. The predetermined pressure is set to a value larger than the drive hydraulic pressure (a hydraulic pressure corresponding to the set load) of the first master piston 14. The predetermined amount is, for example, a preset fixed value (fixed value), a value corresponding to an increase slope of the stroke (for example, an increase slope immediately before the stroke reaches the predetermined value), or a drive amount of the first master piston 14 is This value corresponds to the hydraulic pressure braking force of the front wheel Wf or the rear wheel Wr, which increases when the specified value is increased. The increasing gradient of the servo pressure corresponds to the increasing gradient of the driving amount of the first master piston 14. Further, the adjustment control is performed during regenerative braking in which regenerative braking force is generated.

An example of adjustment control will be described with reference to FIGS. 3 and 4. As shown in FIG. 3, first, at t1 to t2 which is the initial stage of the brake operation, the required braking force is realized only by the regenerative braking force of the rear wheel Wr, and from t2 to t3, the actuator 5 performs pressure control to control the front wheel Wf. The required braking force is realized by the hydraulic pressure braking force generated on the rear wheel and the regenerative braking force of the rear wheel Wr. Then, when the stroke of the brake pedal 10 (input piston 13) reaches a predetermined value at t3, the adjustment control is executed and the servo pressure generator 4 operates to increase the master pressure (servo pressure) with an increasing gradient according to the stroke fluctuation. Increases, and the regenerative braking force is reduced by a predetermined amount with a decreasing slope equal to the increasing slope of the master pressure (absolute value: slope) (t3 to t4). The predetermined amount here is a constant value set in advance. By increasing the servo pressure with a predetermined increase gradient at t3, when the servo pressure reaches the drive hydraulic pressure of the first master piston 14, the first master piston 14 instantaneously advances by a specified value.

From t3 to t4, the servo pressure increases in response to the adjustment control and the increase in the stroke, whereby the first master piston 14 advances. At this time, since the stepping operation is continued, the input piston 13 also advances. From t3 to t5, the increase in the required braking force and the decrease in the regenerative braking force of the rear wheel Wr are compensated by the increase in the master pressure and the pressurization control of the actuator 5 to the rear wheel Wr. After that, the substitution control is executed immediately before the stop.

According to this adjustment control, since the first master piston 14 advances in a situation where the separation distance d is small, the separation distance d is increased (or the reduction of the separation distance d is suppressed), and the input piston 13 and the first master piston Contact with 14 is suppressed. Furthermore, as shown in FIG. 4, the braking force distribution between the front wheels Wf and the rear wheels Wr can be kept good. For example, when the stroke reaches a predetermined value (t3), if control is only performed to increase the servo pressure without a decrease in regenerative braking force, the braking force is high, as indicated by the two-dot chain line in FIG. The braking force will increase in a region away from the ideal distribution line. The distribution of braking force in the region where the braking force is high affects traveling stability more than in the region where the braking force is low.

However, in the adjustment control of the first embodiment, since the regenerative braking force is reduced according to the increase of the master pressure to suppress the increase of the braking force of the rear wheel Wr, during the execution of the adjustment control (t3 to t4) The distribution moves toward the ideal distribution line. Thereafter, at t4 to t5, when the control unit 61 makes the regenerative braking force constant, the fluid pressure braking force of the front wheel Wf and the rear wheel Wr uniformly increases due to the increase of the master pressure, and the braking force increases along the ideal distribution line Do. As a result, in the region where the braking force is high, excessive increase of the braking force of one of the front wheel Wf and the rear wheel Wr is suppressed as compared to the other, and the vehicle stability is favorably maintained. As a vehicle braking device, although the regenerative braking device 8 is provided for the front wheel Wf or the rear wheel Wr as in the first embodiment and the master pressure corresponds to the hydraulic braking force for both the front and rear wheels, Also in this configuration, by reducing the regenerative braking force, it is suppressed that the braking force of one of the front wheel Wf and the rear wheel Wr becomes excessively larger than the other, and appropriate vehicle stability can be exhibited. Further, even if the adjustment control is performed, the generated braking force also becomes a value corresponding to the required braking force due to the increase of the hydraulic pressure braking force and the decrease of the regenerative braking force.

Further, in the first embodiment, the predetermined value which is the threshold value of the stroke relating to the execution of the adjustment control corresponds to a commonly used area (for example, the deceleration is 0.3 G or less) in which a normal brake operation (operation excluding emergency braking) is performed. It is not a value but is set to a value corresponding to a high deceleration region (eg, deceleration is 0.3 to 0.5 G). Thereby, even if the adjustment control is executed, as shown in FIG. 5, although the amount of regeneration in the high deceleration region decreases, the amount of regeneration in the normal use region does not decrease, so the decrease in the amount of regeneration is made extremely small. be able to. For example, when an emergency braking operation is performed, the deceleration reaches a high deceleration region.

Further, if the braking force distribution is adjusted by the pressure adjustment function of the actuator 5 against the increase of the master pressure, the operation noises of various solenoid valves and the locking of the stroke etc. occur, so that the brake feeling deteriorates. Realization of allocation adjustment is practically difficult. However, according to the adjustment control of the first embodiment, no special control needs to be performed on the actuator 5, and these problems do not occur.

In addition, since the control unit 61 increases the decrease gradient of the regenerative braking force as the increase gradient of the stroke increases in the adjustment control, the braking performance can be maintained more accurately. For example, after the stroke reaches a predetermined value at t3, if the stroke is kept constant, as shown in FIG. 6, the adjustment amount causes the drive amount of the first master piston 14 to be a predetermined increase gradient with a predetermined increase gradient. The regenerative braking force is reduced by a predetermined amount with a predetermined decreasing slope so as to increase by as much as and to offset the increase of the hydraulic braking force due to the increase. That is, even if the adjustment control is performed, the braking force corresponding to the required braking force is realized. Then, the separation distance d increases by a specified value.

Second Embodiment
The vehicle brake system according to the second embodiment differs from the first embodiment in that the control device 60 further includes a determination unit 62. Therefore, only the differences will be described. In the description of the second embodiment, the description of the first embodiment and the drawings can be referred to.

As shown in FIG. 7, the control device 60 includes a control unit 61 and a determination unit 62 as functions. The determination unit 62 is configured to determine the probability (the magnitude of the possibility) that the increase gradient of the stroke of the brake pedal 10 is equal to or higher than a reference value (predetermined gradient). The control unit 61 sets the specified value larger as the probability determined by the determination unit 62 is higher. The determination unit 62 determines that the probability is higher as the vehicle speed is higher. The vehicle speed can be calculated based on the detection result of the wheel speed sensor 76, for example. During high speed travel, the possibility of performing an emergency brake operation is higher than during low speed travel. Therefore, when the vehicle speed is equal to or higher than the predetermined speed, the determination unit 62 determines that the probability is high. If the determination unit 62 determines that the probability is high, the control unit 61 increases the specified value (for example, increases the specified value by a fixed amount from the initial value). Thereby, when the adjustment control is executed, the drive amount (for example, the instantaneous drive amount) of the first master piston 14 becomes larger than that at the low speed, and the contact between the input piston 13 and the first master piston 14 can be more reliably. Contact can be suppressed.

<Others>
The present invention is not limited to the above embodiment. For example, when a pumping operation is performed on the brake pedal 10, the control unit 61 may be configured to execute the adjustment control regardless of the magnitude of the stroke. The pumping operation is an operation in which stepping and releasing are repeated in a short period of time, and the control unit 61 can detect, for example, a change in stroke. In the situation where the pumping operation is performed, the separation distance d fluctuates almost periodically, but when a control delay or the like occurs there, when the input piston 13 is moving forward (when the separation distance d is small ) It is also conceivable that the first master piston 14 retracts. Therefore, when the pumping operation is performed, the contact between the input piston 13 and the first master piston 14 is suppressed by the control unit 61 executing the adjustment control in advance regardless of the stroke.

Further, the actuator 5 is not limited to one having a pressurizing function, but may be one having no pressurizing function (for example, an ABS actuator). The servo pressure generator 4 may not have the regulator 44. Further, the regenerative braking device 8 may be provided for the front wheel Wf. Further, the predetermined direction is a direction in which the input piston 13 advances when the brake pedal 10 is depressed, and is described as the front in this embodiment. Moreover, both ECU6 and 6A may be comprised by one ECU.

Claims (5)

1. An input piston which advances in a predetermined direction in the cylinder according to an increase in the stroke of the brake operation member; a master piston which is disposed apart from the input piston in the cylinder in the predetermined direction; The drive unit includes a drive unit that generates a master pressure corresponding to a fluid pressure braking force applied to the wheel by driving in the predetermined direction, and a regenerative braking unit that applies a regenerative braking force to the wheel, and the stroke is increased. The vehicle braking device cooperatively controls the regenerative braking unit and the drive unit while increasing the regenerative braking force of the regenerative braking unit according to
   Control for performing adjustment control to increase the drive amount of the master piston by a specified value by the drive unit and to decrease the regenerative braking force by the regenerative braking unit according to the specified value when the stroke becomes equal to or greater than a predetermined value Braking device for vehicles provided with a part.
2. A determination unit that determines the probability that the increase gradient of the stroke of the brake operation member is equal to or greater than a reference value;
   The vehicle braking device according to claim 1, wherein the control unit sets the predetermined value larger as the probability determined by the determination unit is higher.
3. The vehicular braking apparatus according to claim 2, wherein the determination unit determines that the probability is higher as the vehicle speed is higher.
4. The vehicle according to any one of claims 1 to 3, wherein the control unit executes the adjustment control regardless of the magnitude of the stroke when a pumping operation is performed on the brake operation member. Braking device.
5. The vehicle braking system according to any one of claims 1 to 4, wherein the control unit increases the decrease gradient of the regenerative braking force as the increase gradient of the stroke increases in the adjustment control.

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