JP2012071681A - Braking device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking device for vehicle which can perform regenerative cooperation control without largely changing a conventional braking device.SOLUTION: A primary piston 36 and a secondary piston 33 are movably provided in inside of a cylinder part 311. Thereby a primary chamber PC and a secondary chamber SC are formed. A differential valve 91 is formed between the primary chamber PC and an ABS actuators 5. If driving fluid pressure from a power fluid pressure source 7 is supplied to a driving chamber DC, a primary piston 36 and a secondary piston 33 move inside of the cylinder part 311, and the fluid pressure generates in the primary chamber PC and the secondary chamber SC. The fluid pressure of the primary chamber PC is decompressed by a differential valve 91. In an initial braking, the fluid pressures of wheel cylinders WC 3, WC4 at the rear wheel side is set lower than the wheel cylinders WC 1, WC2 at the front wheel side.

Description

  The present invention relates to a vehicular braking device that generates a hydraulic pressure corresponding to an operation of a brake operating member of a vehicle and supplies the hydraulic pressure to a wheel brake.

Conventionally, in order to efficiently generate braking force while maintaining vehicle stability, there has been a technique for supplying braking force to front and rear wheels of a vehicle so as to approximate ideal distribution. In the past, a number of technologies have been created with the development of control devices related to hydraulic braking.
In recent years, with the spread of hybrid vehicles and electric vehicles, the demand for regenerative cooperative control that brakes wheels by using both regenerative braking and hydraulic braking is increasing. In the technical field of regenerative cooperative control, in order to increase energy recovery efficiency and improve vehicle fuel efficiency, hydraulic braking and regenerative braking can be coordinated so that regenerative braking force can be applied to the drive wheels as much as possible. It is an issue.

  Therefore, in a vehicle that executes regenerative cooperative control, a problem relating to a technique for coordinating hydraulic braking and regenerative braking and a problem relating to distribution adjustment of hydraulic brakes for front and rear wheels coexist. In particular, in a rear-wheel drive vehicle, the wheel on which regenerative braking is executed and the wheel on which the braking force is limited based on the ideal distribution coincide. Also, in a vehicle that is a front and rear wheel drive vehicle but the rear wheel has a higher regenerative capacity than the front wheel, the regenerative braking is performed based on the wheels that have a relatively large braking force and the ideal distribution. The wheels are limited in power. Therefore, how to combine the hydraulic braking and the regenerative braking to generate the braking force on the vehicle has a great influence on the braking efficiency and stability of the vehicle.

  Here, in a rear wheel drive vehicle in which the rear wheels are driven by left and right individual motors, there has been a related art relating to a braking control device that executes regenerative cooperative control (for example, see Patent Document 1). According to the braking control device disclosed in Patent Document 1, the hydraulic braking force of the front and rear wheels is individually controlled by the control unit. Thus, hydraulic braking is performed so that the braking force distribution of the front and rear wheels approaches the ideal distribution while performing regenerative braking on the rear wheels to recover energy.

Japanese Patent Laid-Open No. 9-93711

However, the brake control device disclosed in Patent Document 1 has a complicated configuration and control algorithm for individually controlling the hydraulic braking force of the front and rear wheels. Need to be changed. Therefore, the braking device becomes larger and the cost increases.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a conventional braking device for a rear wheel drive vehicle or a front and rear wheel drive vehicle in which a rear wheel has a higher regenerative capability than a front wheel. An object of the present invention is to provide a vehicular braking apparatus that can execute suitable regenerative cooperative control without significantly changing the above.

  In order to solve the above-described problem, a structural feature of the vehicular braking apparatus according to claim 1 is that a regenerative braking unit that has two front and rear brake pipes and applies a regenerative braking force to the rear wheels is provided. A primary piston that is movable in the cylinder part, and a secondary piston that is movable in the cylinder part, and that is movable in the cylinder part. The primary hydraulic pressure is between the primary piston and the secondary piston. A secondary hydraulic chamber is formed in front of the secondary piston, the primary hydraulic chamber is connected to one of the front wheel side wheel cylinder and the rear wheel side wheel cylinder, and the secondary hydraulic chamber is connected to the front wheel Is connected to the other of the side wheel cylinder and the rear wheel side cylinder, and the primary piston is energized. By moving forward, hydraulic pressure is generated in the primary hydraulic chamber, and the secondary piston moves forward due to the hydraulic pressure generated in the primary hydraulic chamber, generating hydraulic pressure in the secondary hydraulic chamber and braking force on the front and rear wheels. Is provided between the rear wheel side wheel cylinder and the primary hydraulic pressure chamber or the secondary hydraulic pressure chamber, and the rear wheel side wheel cylinder. The differential pressure valve that opens when the hydraulic pressure in the primary hydraulic pressure chamber or the secondary hydraulic pressure chamber is higher than a predetermined set pressure with respect to the hydraulic pressure between the first hydraulic pressure chamber and the differential pressure valve from the start of operation of the brake operating member The regenerative braking unit includes regenerative braking control means for applying a regenerative braking force according to the operation amount detected by the brake operation amount detecting means to the rear wheels.

  The structural feature of the invention according to claim 2 is the brake operation member according to claim 1, wherein the operation amount of the brake operation member is opened after the operation of the brake operation member is started. The regenerative braking control means until the operation amount of the brake operation member reaches the second predetermined value from the start of operation of the brake operation member until the second predetermined value smaller than the first predetermined value which is the operation amount of During this time, a regenerative braking force corresponding to the operation amount of the brake operation member is applied to the rear wheels.

  According to a third aspect of the present invention, in the vehicular braking apparatus according to the second aspect, an input piston that is connected to a brake operation member and is movable in the cylinder portion is provided behind the primary piston. When the brake operation member is not operated, a predetermined interval corresponding to the second predetermined value is provided between the primary piston and the input piston.

  The structural feature of the invention according to claim 4 is the vehicle braking apparatus according to any one of claims 1 to 3, wherein the rear wheel wheel cylinder and the primary hydraulic chamber or the secondary hydraulic chamber are disposed between the rear wheel side cylinder and the primary hydraulic chamber. In addition, a check valve that allows only the flow of the brake fluid from the rear wheel side wheel cylinder to the primary hydraulic pressure chamber or the secondary hydraulic pressure chamber is provided in parallel with the differential pressure valve.

  The structural feature of the invention according to claim 5 is the vehicle braking device according to claim 4, wherein the operation amount of the brake operation member is less than a first predetermined value that is the operation amount of the brake operation member that opens the differential pressure valve. In this case, a hydraulic braking control means for increasing / decreasing the hydraulic braking force of the front wheels according to the increase / decrease of the regenerative braking force of the rear wheels by the regenerative braking control means is provided.

  According to the vehicular braking apparatus of the first aspect, even when hydraulic pressure is generated in the primary hydraulic chamber or the secondary hydraulic chamber, the hydraulic pressure and the hydraulic pressure in the rear wheel side cylinders from the start of operation of the brake operating member. Until the pressure difference from the pressure reaches the set pressure of the differential pressure valve, the differential pressure valve does not open, and the hydraulic pressure in the rear wheel side cylinder does not increase. Therefore, during this time, by applying a regenerative braking force according to the amount of operation of the brake operation member to the rear wheel, it is possible to improve the regenerative efficiency, and the vehicle is stabilized by applying the regenerative braking force to the rear wheel. Sex is not impaired.

That is, it is possible to perform suitable regenerative cooperative control that efficiently applies the braking force while maintaining the stability of the vehicle and increases the regenerative efficiency.
In addition, since the above-described suitable regenerative cooperative control can be performed by providing a differential pressure valve between the primary hydraulic chamber or the secondary hydraulic chamber and the rear wheel side wheel cylinder, the conventional braking device is significantly changed. There is no need.

In the vehicle braking device according to claim 2, no hydraulic pressure is generated in the primary hydraulic pressure chamber until the operation amount of the brake operating member reaches the second predetermined value after the operation of the brake operating member is started. .
Therefore, until the amount of operation of the brake operation member reaches the second predetermined value, no hydraulic braking force is applied to the front and rear wheels, so that all of the braking force corresponding to the amount of operation of the brake operation member is used as the regenerative braking force. The regenerative braking force can be sufficiently generated at the time of initial braking.

According to the vehicle braking device of the third aspect, when the input piston that is connected to the brake operation member and is movable in the cylinder portion is provided behind the primary piston, and the brake operation member is not operated. In addition, a predetermined interval is provided between the primary piston and the input piston so that the operation amount of the brake operation member corresponds to the second predetermined value.
Thus, in the initial braking, the input piston does not come into contact with the primary piston until the operation amount of the brake operation member reaches the second predetermined value, so that the primary piston does not contact the primary piston. The invalid stroke region of the brake operating member that does not generate hydraulic pressure can be reliably formed.

According to the vehicle braking apparatus of the fourth aspect, the check valve that allows only the flow of the brake fluid from the rear wheel side wheel cylinder to the primary hydraulic chamber or the secondary hydraulic chamber is provided in parallel with the differential pressure valve. ing.
As a result, when the hydraulic pressure in the primary hydraulic chamber or the secondary hydraulic chamber becomes lower than the hydraulic pressure in the rear wheel cylinder by returning the operation of the brake operation member, the rear wheel side is set via the check valve. The brake fluid in the wheel cylinder is returned to the primary hydraulic chamber or the secondary hydraulic chamber.
Therefore, regardless of the operating state of the differential pressure valve, the hydraulic pressure of the rear wheel side cylinder can be reduced according to the decrease in the operation amount of the brake operation member.

  In the vehicle brake device according to claim 4, the brake fluid of the rear wheel side wheel cylinder is caused to flow out to the primary hydraulic chamber or the secondary hydraulic chamber via the check valve, and the hydraulic pressure of the rear wheel side wheel cylinder is reduced. In order to lower the pressure, it is necessary to make the hydraulic pressure in the primary hydraulic chamber or the secondary hydraulic chamber lower than the hydraulic pressure in the rear wheel side cylinder as described above. By increasing or decreasing the hydraulic braking force of the front wheel, it is possible to compensate for the increase or decrease of the regenerative braking force of the rear wheel side wheel cylinder.

The block diagram which showed the control system for vehicles by Embodiment 1 of this invention The figure which showed typically the hydraulic brake device shown in FIG. The figure which showed the state at the time of the initial stage braking of the hydraulic brake device shown in FIG. The figure which showed the state by which the hydraulic braking to the rear wheel was started in the hydraulic brake device shown in FIG. The figure which showed the relationship between the front braking force and the rear braking force centering on the time of the initial braking in the vehicle control system shown in FIG. The figure which showed the relationship between the amount of brake operation in the vehicle control system shown in FIG. 1, and vehicle braking force The figure which showed the modification 1 of the pressure reduction means The figure which showed the modification 2 of the pressure reduction means The figure which showed typically the hydraulic brake device by Embodiment 2 of this invention. The figure which showed the state at the time of the initial braking of the hydraulic brake device shown in FIG. FIG. 9 is a diagram showing a state in which the application of the hydraulic braking force to the front wheels is started in the hydraulic brake device shown in FIG. The figure which showed the relationship between the amount of brake operation, and vehicle braking force in the control system for vehicles by other embodiment.

<Embodiment 1>
A first embodiment in which the hydraulic brake device B according to the present invention is applied to a hybrid vehicle will be described with reference to FIGS. FIG. 1 is a schematic diagram showing the configuration of the hybrid vehicle, and FIG. 2 is a schematic diagram showing the configuration of the hydraulic brake device B.
As shown in FIG. 1, the hybrid vehicle is a vehicle that drives left and right rear wheels RL and RR that are drive wheels by a hybrid system. The hybrid system is a power train that uses a combination of two types of power sources, the engine 11 and the motor 12. In the case of the present embodiment, the parallel hybrid system is a system in which wheels are directly driven by both the engine 11 and the motor 12. In addition to this, there is a serial hybrid system, in which wheels are driven by a motor 12, and the engine 11 functions as a power source for power generation. The present invention can also be applied to a serial hybrid system.

In the hybrid vehicle equipped with this parallel hybrid system, the driving force of the engine 11 is transmitted to the left and right rear wheels RL and RR via the power split mechanism 13 and the power transmission mechanism 14, and the motor 12 is driven. The force is transmitted to the left and right rear wheels RL and RR via the power transmission mechanism 14.
The power split mechanism 13 appropriately splits the driving force of the engine 11 into a vehicle driving force and a generator driving force. The power transmission mechanism 14 appropriately integrates the driving forces of the engine 11 and the motor 12 according to traveling conditions and transmits them to the driving wheels. The power transmission mechanism 14 adjusts the driving force ratio transmitted between the engine 11 and the motor 12 between 0: 100 and 100: 0. The power transmission mechanism 14 has a speed change function.

  The motor 12 assists the output of the engine 11 and increases the driving force. On the other hand, the motor 12 generates power when the vehicle is braked and charges the battery 17. The generator 15 generates power based on the output of the engine 11 and has a starter function when starting the engine. The motor 12 and the generator 15 are electrically connected to the inverter 16, respectively. The inverter 16 is electrically connected to a battery 17 serving as a DC power source. The inverter 16 converts the AC voltage input from the motor 12 and the generator 15 into a DC voltage and supplies it to the battery 17. A DC voltage is converted into an AC voltage and output to the motor 12 and the generator 15.

In the present embodiment, a regenerative brake device A is constituted by the motor 12, the inverter 16 and the battery 17, and the regenerative brake device A (corresponding to a regenerative braking unit) is a pedal stroke sensor 22a or a pedal depression force sensor 22b. The regenerative braking force based on the brake operation state detected by the above is generated on the left and right rear wheels RL and RR driven by the motor 12 as a drive source.
The engine 11 is controlled by an engine ECU (electronic control unit) 18. The engine ECU 18 outputs an opening degree command to an electronic control throttle according to an engine output request value from a hybrid ECU (electronic control unit) 19 described later. Adjust the rotation speed.

  An inverter 16 is connected to the hybrid ECU 19 (corresponding to regenerative braking control means) so as to be able to communicate with each other. The hybrid ECU 19 derives necessary engine output, electric motor torque, and generator torque from the accelerator opening and shift position (calculated from a shift position signal input from a shift position sensor not shown), and the derived engine output request value Is transmitted to the engine ECU 18 to control the driving force of the engine 11, and the motor 12 and the generator 15 are controlled through the inverter 16 in accordance with the derived electric motor torque request value and generator torque request value.

  In addition, a battery 17 is connected to the hybrid ECU 19 to monitor a charging state, a charging current, and the like of the battery 17. Further, the hybrid ECU 19 is also connected to an accelerator opening sensor (not shown) that is assembled to an accelerator pedal (not shown) and detects the accelerator opening of the vehicle, and inputs an accelerator opening signal from the accelerator opening sensor. ing.

Further, the hybrid vehicle includes a hydraulic brake device B that applies a hydraulic braking force to the wheels FL, FR, RL, and RR directly and brakes the vehicle through two brake systems of front and rear. The hydraulic brake device B includes a master cylinder 3 that generates a hydraulic pressure corresponding to an operation amount of the brake pedal 22, a reservoir tank 23 that stores the brake fluid and supplies the brake fluid to the master cylinder 3, and the master cylinder 3. And a wheel actuator WC1 to WC4 (shown in FIG. 2) attached to each wheel FL, FR, RL, RR, and a brake actuator D that forms a control hydraulic pressure.
Further, wheel speed sensors Sfl, Sfr, Srl, Srr are attached to the wheels FL, FR, RL, RR, respectively, and the detected values are inputted to the brake ECU 21, and the control hydraulic pressure of the brake actuator D is controlled. Used for forming.

  The hydraulic brake device B transmits a depression operation of the brake pedal 22 (corresponding to a brake operation member) to the master cylinder 3 by the push rod 24, and the hydraulic pressure corresponding to the operation amount of the brake pedal 22 is transmitted by the master cylinder 3. The generated hydraulic pressure is applied to the wheel cylinders WC1, WC2, WC3, WC4 of the wheels FL, FR, RL, RR connected via the brake actuator D, so that the wheels FL, FR, RL , A hydraulic braking force corresponding to the hydraulic pressure generated in RR is generated.

The brake pedal 22 includes a pedal stroke sensor 22a (corresponding to the brake operation amount detection means of the present invention) that detects the amount of brake pedal stroke caused by the depression of the brake pedal 22, and a pedal depression force that detects a reaction force received by the brake pedal 22. A sensor 22b is provided. The pedal stroke sensor 22a and the pedal depression force sensor 22b are connected to the brake ECU 21 so that a detection signal is transmitted to the brake ECU 21.
The brake ECU 21 (corresponding to the hydraulic braking control means of the present invention) is connected to the hybrid ECU 19 and the brake actuator D, and operates the brake actuator D based on the state of the regenerative brake device A input from the hybrid ECU 19. Control.

  Next, the master cylinder 3 will be described with reference to FIG. In the description, the left side in FIG. 2 (the direction in which the push rod 24 moves when the brake pedal 22 is depressed) is in front of the master cylinder 3 and the right side (the direction in which the push rod 24 moves when the brake pedal 22 returns). Will be described as the rear of the master cylinder 3. The master cylinder 3 is formed by a tandem master cylinder having a primary chamber PC and a secondary chamber SC. A cylinder portion 311 is formed inside the cylinder body 31 of the master cylinder 3.

  The secondary piston 33 is formed in a substantially U-shaped cross section and is accommodated in the cylinder portion 311 so as to face the bottom of the cylinder portion 311. The outer peripheral surface of the secondary piston 33 is in contact with the first seal cup 34 a and the second seal cup 34 b provided on the inner peripheral surface of the cylinder portion 311, and is slidable and liquid-tightly fitted to the cylinder portion 311. is doing. Thereby, it seals by the 1st seal cup 34a, and the secondary chamber SC (corresponding to the secondary hydraulic pressure chamber of the present invention) is formed ahead of the secondary piston 33 by the cylinder part 311 and the secondary piston 33. A first communication port 331 that connects the outer peripheral surface of the secondary piston 33 and the secondary chamber SC passes through the front portion of the secondary piston 33.

  A secondary spring 35 is elastically interposed between the recess 332 of the secondary piston 33 and the bottom of the cylinder portion 311. A stopper bolt (not shown) is screwed onto the cylinder body 31 to receive the rear portion of the secondary piston 33 that receives the urging force from the secondary spring 35.

  A primary piston 36 is movably accommodated in the cylinder portion 311 so as to be positioned behind the secondary piston 33. The primary piston 36 has a substantially H-shaped cross section, and the outer peripheral surface thereof abuts on the third seal cup 34 c and the fourth seal cup 34 d provided on the inner peripheral surface of the cylinder portion 311, and the cylinder portion 311. Is liquid-tightly fitted.

  Thus, the second seal cup 34b and the third seal cup 34c are sealed, and the primary chamber PC (corresponding to the primary hydraulic pressure chamber of the present invention) is formed by the cylinder portion 311, the secondary piston 33 and the primary piston 36. Yes. A second communication port 361 that connects the outer peripheral surface of the primary piston 36 and the primary chamber PC passes through the front portion of the primary piston 36.

A spring support portion 333 protrudes from the rear end portion of the secondary piston 33, and one end portion of the primary spring 40 is engaged with the spring support portion 333. The other end of the primary spring 40 is in contact with the recess 362 of the primary piston 36, and the primary spring 40 is elastically interposed between the secondary piston 33 and the primary piston 36.
A support wall 312 protrudes radially inward from the cylinder body 31 behind the primary piston 36. The primary piston 36 that receives a rearward urging force from the primary spring 40 is positioned when its rear end abuts against the front end surface of the support wall 312 when the brake pedal 22 is not operated (shown in FIG. 2).

A sliding hole 312a passes through the support wall 312, and a first seal ring 41a is attached to the sliding hole 312a. An input piston 43 is inserted into the cylinder body 31 from the rear, and a small diameter portion 431 of the input piston 43 is movably fitted in the sliding hole 312a. The outer peripheral surface of the input piston 43 is fluid-tightly fitted to the sliding hole 312a by contacting the first seal ring 41a.
The small-diameter portion 431 faces the rear end of the primary piston 36, is sealed by the fourth seal cup 34d and the first seal member 41a, and is driven behind the primary piston 36 by the cylinder body 31, the primary piston 36, and the input piston 43. DC is formed.

The input piston 43 is formed by a small-diameter portion 431 formed in the front, a large-diameter portion 432 in the center in the axial direction, and a small-diameter connecting portion 433 formed in the rear. In the cylinder body 31, an input cylinder 313 (including the cylinder portion 311 and included in the cylinder portion of the present invention) is formed so as to be positioned behind the support wall 312. A large diameter portion 432 of the input piston 43 is slidably fitted to the input cylinder 313. A second seal ring 41 b is mounted on the outer peripheral surface of the large diameter portion 432, and the large diameter portion 432 is fitted in a liquid-tight manner with respect to the input cylinder 313.
As a result, the first seal member 41 a and the second seal member 41 b are sealed, and the input cylinder 313 and the input piston 43 form an annular reaction force chamber RC.

Further, the outer peripheral surface of the connecting portion 433 of the input piston 43 is slidably fitted into an insertion hole 315 formed in the rear end wall 314 of the cylinder body 31. The connecting portion 433 is in contact with the third seal ring 41c mounted in the insertion hole 315 and is fitted in the insertion hole 315 in a liquid-tight manner. Thus, the second sealing ring 41 b and the third sealing ring 41 c are sealed, and the compensation chamber CC is formed by the input cylinder 313 and the input piston 43 behind the large diameter portion 432.
Further, in the input piston 43, a both-part connecting hole 434 that opens to the front end portion of the small diameter portion 431 and the outer peripheral surface of the connecting portion 433 is formed. As shown in FIG. 2, the drive chamber DC and the compensation chamber CC are communicated with each other through the both-part connecting holes 434.

  An engagement concave portion 435 is formed in the rear portion of the input piston 43, and the push rod 24 described above is attached to the engagement concave portion 435 so as to be swingable and not dropout. The push rod 24 is attached to the brake pedal 22, whereby the input piston 43 is connected to the brake pedal 22 via the push rod 24. The input piston 43 is pulled rearward under the urging force of a return spring (not shown) attached to the brake pedal 22, and the rear end surface of the large diameter portion 432 comes into contact with the rear end wall 314 of the cylinder body 31.

When the large diameter portion 432 contacts the rear end wall 314, positioning is performed when the input piston 43 is at the rearmost position when the brake pedal 22 is not operated. In the state where the input piston 43 is located at the rearmost position, a gap S ₀ is formed between the front end portion of the input piston 43 and the rear surface of the primary piston 36 facing the input piston 43 (shown in FIG. 2).
This interval S ₀ is a movement amount (hereinafter referred to as “second predetermined value”) from when the operation of the brake pedal 22 is started until the front end of the input piston 43 comes into contact with the rear surface of the primary piston 36. This corresponds to the “predetermined interval” of the present invention. The provision of the gap _{S 0,} during the initial braking in, until the stroke amount of the brake pedal 22 reaches a second predetermined value, the front wheels FL, FR and the rear wheels RL, foil RR cylinders WC1, WC2, WC3 , An increase in brake hydraulic pressure applied to WC4 is suppressed (no hydraulic pressure is supplied to wheel cylinders WC1, WC2, WC3, WC4).

A pair of bosses 316a and 316b to which the above-described reservoir tank 23 is attached are formed on the upper portion of the cylinder body 31. In addition, a pair of supply ports 317 a and 317 b that allow the supply of brake fluid from the reservoir tank 23 to the secondary chamber SC and the primary chamber PC pass through the cylinder body 31.
Further, the cylinder body 31 is provided with output ports 318a and 318b for connecting the secondary chamber SC and the primary chamber PC to the ABS actuator 5 (described later). Further, the cylinder body 31 is formed with a power port 318c for connecting the driving chamber DC to a power hydraulic pressure source 7 (described later). Further, a dummy port 318 d for connecting the reaction force chamber RC to the power hydraulic pressure source 7 is formed in the cylinder body 31.

  Next, the ABS actuator 5 included in the brake actuator D will be described with reference to FIG. The ABS actuator 5 is a known one for performing anti-skid control. The pressure increase control valves 51, 52, 53, and 54, which are normally open solenoid valves, and the pressure reduction control valve 55, which is a normally closed solenoid valve. , 56, 57, 58, pressure regulating reservoirs 59, 61 for accommodating brake fluid discharged from the wheel cylinders WC1, WC2, WC3, WC4, and return of the brake fluid in the pressure regulating reservoirs 59, 61 to the master cylinder 3 side The motor 62 drives the pumps 62 and 63 and the reflux pumps 62 and 63.

  A main pipe Lp, which is a brake pipe, is connected to the output port 318b that communicates with the primary chamber PC. Further, a main pipe Ls that is a brake pipe is connected to the output port 318a that communicates with the secondary chamber SC. A pair of pressure increasing lines Lp1, Lp2 is connected to the main line Lp, and the pressure increasing lines Lp1, Lp2 are connected to the wheel cylinder WC3 of the left rear wheel RL and the wheel cylinder WC4 of the right rear wheel RR, respectively. Yes. A pair of pressure increasing lines Ls1, Ls2 is connected to the main line Ls, and the pressure increasing lines Ls1, Ls2 are connected to the wheel cylinder WC1 of the left front wheel FL and the wheel cylinder WC2 of the right front wheel FR, respectively. Yes.

  Pressure increase control valves 53 and 54 are disposed in the pressure increase lines Lp1 and Lp2, respectively, and check valves 53a and 54a permitting the flow of brake fluid from the wheel cylinders WC3 and WC4 to the main line Lp, respectively. Is arranged in parallel to the pressure increase control valves 53 and 54. The pressure increase control valves 53 and 54 are connected to the brake ECU 21 and are controlled to be opened and closed by the brake ECU 21.

  Further, pressure increase control valves 51 and 52 are disposed in the pressure increase lines Ls1 and Ls2, respectively, and a check valve 51a that allows the flow of brake fluid from the wheel cylinders WC1 and WC2 toward the main line Ls, respectively. , 52a are arranged in parallel to the pressure increase control valves 51, 52. The pressure increase control valves 51 and 52 are connected to the brake ECU 21 and are controlled to be opened and closed by the brake ECU 21.

A pressure reducing line Lp3 is connected to a portion of the pressure increasing line Lp1 between the pressure increasing control valve 53 and the wheel cylinder WC3. The pressure reducing line Lp3 connects the pressure increasing line Lp1 and the pressure regulating reservoir 61. A pressure reduction control valve 57 is disposed in the pressure reduction line Lp3. The pressure reduction control valve 57 is connected to the brake ECU 21 and is controlled to be opened and closed by the brake ECU 21.
Further, a pressure reducing line Lp4 is connected to a portion between the pressure increasing control valve 54 and the wheel cylinder WC4 in the pressure increasing line Lp2. The pressure reducing line Lp4 connects the pressure increasing line Lp2 and the pressure regulating reservoir 61. A pressure reducing control valve 58 is disposed in the pressure reducing line Lp4. The pressure reduction control valve 58 is connected to the brake ECU 21 and is controlled to be opened and closed by the brake ECU 21.

Further, a pressure reducing line Ls3 is connected to a portion of the pressure increasing line Ls1 between the pressure increasing control valve 51 and the wheel cylinder WC1. The pressure reducing line Ls3 connects the pressure increasing line Ls1 and the pressure regulating reservoir 59. A decompression control valve 55 is disposed in the decompression line Ls3. The pressure reduction control valve 55 is connected to the brake ECU 21 and is controlled to be opened and closed by the brake ECU 21.
Further, a pressure reducing line Ls4 is connected to a portion of the pressure increasing line Ls2 between the pressure increasing control valve 52 and the wheel cylinder WC2. The pressure reducing line Ls4 connects the pressure increasing line Ls2 and the pressure regulating reservoir 59. A decompression control valve 56 is disposed in the decompression line Ls4. The pressure reduction control valve 56 is connected to the brake ECU 21 and is controlled to be opened and closed by the brake ECU 21.

  The pressure regulation reservoir 61 is connected to the main pipeline Lp by a reflux pipeline Lp5. A reflux pump 63 is provided in the reflux line Lp5, and a portion between the pressure regulating reservoir 61 and the reflux pump 63 and a portion between the reflux pump 63 and the main pipeline Lp are connected from the pressure regulating reservoir 61 to the main pipe. A pair of check valves 65a and 65b that allow the flow of the brake fluid toward the path Lp are provided. The recirculation pump 63 is controlled by the brake ECU 21 to recirculate the brake fluid in the pressure regulating reservoir 61 to the main line Lp.

  Further, the pressure regulating reservoir 59 is connected to the main pipeline Ls by a reflux pipeline Ls5. A reflux pump 62 is provided in the reflux line Ls5, and a portion between the pressure regulating reservoir 59 and the reflux pump 62 and a portion between the reflux pump 62 and the main pipeline Ls are connected from the pressure regulating reservoir 59 to the main pipe. A pair of check valves 64a and 64b that allow the flow of the brake fluid toward the path Ls are provided. The recirculation pump 62 is controlled by the brake ECU 21 to recirculate the brake fluid in the pressure regulating reservoir 59 to the main line Ls.

  The ABS actuator 5 is controlled by the brake ECU 21 and adjusts the hydraulic pressure generated by the master cylinder 3 based on the detection values of the wheel speed sensors Sfl, Sfr, Srl, Srr to the wheel cylinders WC1, WC2, WC3, WC4. Supply and execute anti-skid control. Since the ABS actuator 5 is known and is not the subject of the present invention, further detailed description is omitted.

  On the other hand, the power hydraulic pressure source 7 included in the brake actuator D includes a reservoir 71, a pair of power pumps 72 and 73 that suck and discharge the brake fluid in the reservoir 71, a motor 74 that drives the power pumps 72 and 73, Part of the brake fluid discharged from the power pumps 72 and 73 is returned to the reservoir 71, and linear pressure reducing valves 75 and 76 which are electromagnetic linear valves for adjusting the pressure are provided.

  The power pump 72 on one side is connected to the reservoir 71 by a suction line PL1. An output line PL3 is connected to the discharge port of the power pump 72, and the output line PL3 is connected to the dummy port 318d of the master cylinder 3 described above. The power pump 72 is connected to the brake ECU 21 and the operation is controlled by the brake ECU 21. Further, a pressure sensor 77 is disposed in a portion of the output line PL3 between the power pump 72 and the dummy port 318d. The value detected by the pressure sensor 77 is input to the brake ECU 21.

  A discharge line PL5 is connected to a portion of the output line PL3 between the power pump 72 and the dummy port 318d. The discharge line PL5 connects the output line PL3 to the reservoir 71. The output line PL5 is provided with a linear pressure reducing valve 75. The linear pressure reducing valve 75 is connected to the brake ECU 21 and controlled by the brake ECU 21. In addition, a check valve 75a that allows the flow of brake fluid from the reservoir 71 to the dummy port 318d is disposed in parallel to the linear pressure reducing valve 75 in the discharge line PL5. With the above-described configuration, a reaction force power system that supplies the generated hydraulic pressure to the reaction force chamber RC is configured.

  On the other hand, the power pump 73 on the other side is connected to the reservoir 71 by a suction line PL2. An output line PL4 is connected to the discharge port of the power pump 73, and the output line PL4 is connected to the power port 318c. The power pump 73 is connected to the brake ECU 21 and the operation is controlled by the brake ECU 21. Further, a pressure sensor 78 is disposed in a portion of the output line PL4 between the power pump 73 and the power port 318c. A value detected by the pressure sensor 78 is input to the brake ECU 21.

  A discharge line PL6 is connected to a portion of the output line PL4 between the power pump 73 and the power port 318c. The discharge line PL6 connects the output line PL4 to the reservoir 71. The output line PL6 is provided with a linear pressure reducing valve 76, which is connected to the brake ECU 21 and controlled by the brake ECU 21. In addition, a check valve 76a that allows the flow of brake fluid from the reservoir 71 to the power port 318c is disposed in parallel to the linear pressure reducing valve 76 in the discharge pipe PL6. With the configuration described above, a driving power system that supplies the generated hydraulic pressure to the driving chamber DC is configured.

  The brake ECU 21 controls the power pump 72 and the linear pressure reducing valve 75 based on the detected value by the pedal stroke sensor 22a, the detected value by the pedal depression force sensor 22b, and the detected value by the pressure sensor 77. In the reaction force power system of the power hydraulic pressure source 7, the power pump 72 sucks and discharges the brake fluid in the reservoir 71 and returns a part of the brake fluid discharged through the linear pressure reducing valve 75 to the reservoir 71. By adjusting the pressure, the reaction force drive hydraulic pressure corresponding to the stroke amount of the brake pedal 22 is generated. The reaction force drive hydraulic pressure is applied to the reaction force chamber RC to urge the input piston 43 of the master cylinder 3 rearward to generate a reaction force corresponding to the stroke amount of the brake pedal 22.

  Further, the brake ECU 21 controls the power pump 73 and the linear pressure reducing valve 76 based on the detection value by the pedal stroke sensor 22a and the detection value by the pressure sensor 78. In the driving force power system of the power hydraulic pressure source 7, the power pump 73 sucks and discharges the brake fluid in the reservoir 71 and returns a part of the brake fluid discharged via the linear pressure reducing valve 76 to the reservoir 71. Thus, the servo drive hydraulic pressure corresponding to the stroke amount of the brake pedal 22 is generated.

The servo drive hydraulic pressure is applied to the drive chamber DC to advance the primary piston 36 in the cylinder portion 311. As a result, the brake fluid pressure corresponding to the stroke amount of the brake pedal 22 is generated in the primary chamber PC and the secondary chamber SC of the master cylinder 3 to apply a braking force to the wheels FL, FR, RL, RR.
As is clear from the above description, in the power hydraulic pressure source 7, the reaction driving hydraulic pressure and the servo driving hydraulic pressure can be adjusted independently of each other, and both can be set to different values. It is.

  A differential pressure valve 91 is provided between the primary chamber PC of the main line Lp and the ABS actuator 5. The differential pressure valve 91 is a normally open solenoid control valve, and is included in the brake actuator D. The differential pressure valve 91 is connected to the brake ECU 21 and controlled by the brake ECU 21. The differential pressure valve 91 opens when the hydraulic pressure at the input port to which the primary chamber PC is connected is higher than the hydraulic pressure at the output port connected to the ABS actuator 5 by a predetermined set pressure or higher. It is variable depending on the supply current.

  As a result, the brake hydraulic pressure applied to the wheel cylinders WC3, WC4 on the rear wheels RL, RR side increases until the stroke amount of the brake pedal 22 reaches the first predetermined value after reaching the second predetermined value. The brake fluid pressure is applied to the wheel cylinders WC1 and WC2 on the front wheels FL and FR, but the brake fluid pressure is not applied to the wheel cylinders WC3 and WC4 on the rear wheels RL and RR. ing. Here, the first predetermined value is such that the brake fluid pressure in the primary chamber PC with respect to the brake fluid pressure of the wheel cylinders WC3, WC4 on the rear wheels RL, RR side reaches the set pressure of the differential pressure valve 91 during the initial braking, and the differential pressure valve 91 This is the stroke amount of the brake pedal 22 to be opened.

Between the primary chamber PC of the main pipe Lp and the ABS actuator 5, only the flow of the brake fluid from the wheel cylinders WC3, WC4 on the rear wheels RL, RR side to the primary chamber PC is parallel to the differential pressure valve 91. A permissible check valve 91a is provided.
Thereby, when the stroke of the brake pedal 22 is returned and the servo driving hydraulic pressure supplied to the driving chamber DC decreases, the hydraulic pressure in the primary chamber PC is higher than the hydraulic pressure in the rear wheel RL, RR side wheel cylinders WC3, WC4. When it becomes low, the brake fluid of the rear wheel RL, RR side wheel cylinders WC3, WC4 is returned to the primary chamber PC via the check valve 91a.

  Further, a pressure sensor 92 is provided between the differential pressure valve 91 and the ABS actuator 5 in the main line Lp. In the present embodiment, the pressure sensor 92 detects the hydraulic pressure in the wheel cylinders WC3 and WC4 (downstream of the differential pressure valve 91). Further, as will be described later, since the servo drive hydraulic pressure of the power hydraulic pressure source 7 supplied to the drive chamber DC and the brake hydraulic pressure generated in the primary chamber PC are substantially equal, the hydraulic pressure value generated in the primary chamber PC Is substituted by the detection value of the pressure sensor 78 provided in the power hydraulic pressure source 7. A pressure sensor may be disposed between the primary chamber PC and the differential pressure valve 91 on the main line Lp to detect the hydraulic pressure in the primary chamber PC.

Here, if the first predetermined value related to the stroke amount of the brake pedal 22 in the present embodiment is described in relation to the mechanical configuration of the hydraulic brake device B, the cylinder portion of the input piston 43 corresponding to the first predetermined value. The movement amount in 311 is set to St = S ₀ + T (the stroke amount of the brake pedal 22 is converted into the movement amount of the input piston 43 by the lever ratio of the brake pedal 22).

The movement amount S ₀ of the input piston 43 is set so as to correspond to the operation amount of the brake pedal 22 when the regenerative braking force by the regenerative braking device A reaches the upper limit and the servo drive hydraulic pressure is supplied to the drive chamber DC. Has been. Therefore, the stroke amount of the brake pedal 22 when the front end of the input piston 43 comes into contact with the rear surface of the primary piston 36 corresponds to the second predetermined value.

Further, the movement amount T of the input piston 43 is such that the differential pressure valve 91 is opened after the front end of the input piston 43 comes into contact with the rear surface of the primary piston 36, and the wheel cylinders WC3, WC4 on the rear wheels RL, RR side. This corresponds to the amount of movement until the hydraulic pressure starts to rise, and the stroke amount of the brake pedal 22 at that time corresponds to the first predetermined value. Of course, it goes without saying that the relationship is first predetermined value> second predetermined value.
In the hydraulic brake device B described above, when the stroke amount of the brake pedal 22 is less than the second predetermined value, the brake ECU 21 does not generate servo drive hydraulic pressure in the power hydraulic pressure source 7 and counteracts it. A driving hydraulic pressure for force is generated, and a regenerative braking force is applied to the driving side (rear wheel side) wheels RL and RR by the regenerative braking device A.

  On the other hand, when the stroke of the brake pedal 22 is equal to or greater than the second predetermined value, the brake ECU 21 causes the power hydraulic pressure source 7 to generate servo driving hydraulic pressure and reaction force driving hydraulic pressure.

Next, an operation method of the hydraulic brake device B will be described with reference to FIGS. Note that the operation of the hydraulic brake device B in the description assumes a normal brake operation, and the ABS actuator 5 is not operated.
(1) Operation at normal time (i) Operation when the stroke amount of the brake pedal 22 is less than the second predetermined value First, when the stroke of the brake pedal 22 is started by the driver of the vehicle, the input piston 43 is It is urged by the push rod 24 and moves forward in the cylinder portion 311. However, when it is determined by the brake ECU 21 that the stroke amount of the brake pedal 22 is less than the second predetermined value based on the signal from the pedal stroke sensor 22a, the driving power of the power hydraulic pressure source 7 depends on the power system. Servo drive hydraulic pressure is not generated.

On the other hand, until the movement amount of the input piston 43 reaches S ₀ , the front end of the input piston 43 and the rear surface of the primary piston 36 do not contact each other, and the primary piston 36 does not advance in the cylinder portion 311. There is no hydraulic pressure. Since no hydraulic pressure is generated in the primary chamber PC, the secondary piston 33 does not move forward, and no hydraulic pressure is generated in the secondary chamber SC. Thus, no hydraulic pressure is generated in both the primary chamber PC and the secondary chamber SC, so that no brake hydraulic pressure is supplied to the wheel cylinders WC1, WC2, WC3, WC4 of the wheels FL, FR, RL, RR.

On the other hand, in the above case, only regenerative braking by the regenerative braking device A is performed on the driving wheels RL and RR (indicated by A in FIG. 5 and indicated by E in FIG. 6). Thereby, only the braking force of the rear wheels RL and RR is increased.
Here, as the input piston 43 advances, the volume of the drive chamber DC decreases. However, the volume of the drive chamber DC decreases and the volume of the compensation chamber CC increases as the input piston 43 advances. Are set to be equal to each other, the forward movement of the input piston 43 only causes the brake fluid in the drive chamber DC to move to the compensation chamber CC via the both-part connecting holes 434, and the drive chamber DC and the compensation chamber CC. There is no hydraulic pressure inside.

When the brake pedal 22 is stroked, the brake ECU 21 uses the reaction force power system of the power hydraulic pressure source 7 to generate the brake pedal 22 based on the values detected by the pedal stroke sensor 22a, the pedal depression force sensor 22b, and the pressure sensor 77. The reaction force drive hydraulic pressure corresponding to the stroke amount is generated and supplied to the reaction force chamber RC. The input piston 43 is urged rearward by the reaction force drive hydraulic pressure supplied to the reaction force chamber RC, and a reaction force corresponding to the stroke amount of the brake pedal 22 is generated.
(Ii) Operation when the stroke amount of the brake pedal 22 is greater than or equal to the second predetermined value and less than the first predetermined value The input piston 43 moves forward by the movement amount S ₀ , and the stroke amount of the brake pedal 22 is 2 When it is determined that the predetermined value has been reached (indicated by point p in FIG. 5), the brake ECU 21 drives the power hydraulic pressure source 7 based on the detected value by the pedal stroke sensor 22a and the detected value by the pressure sensor 78. A servo drive hydraulic pressure corresponding to the stroke amount of the brake pedal 22 is generated by the force power system, and the servo drive hydraulic pressure is supplied to the drive chamber DC (shown in FIG. 3). In the present embodiment, it is assumed that the regenerative braking force by the regenerative braking device A has reached the upper limit at this point. Thus, the regeneration efficiency can be increased by setting the second predetermined value.

When the servo drive hydraulic pressure is supplied to the drive chamber DC, the primary piston 36 of the master cylinder 3 is urged by the servo drive hydraulic pressure and moves forward in the cylinder portion 311. When the primary piston 36 moves forward, the primary piston 36 separates from the input piston 43 and moves forward in the cylinder portion 311.
As a result, a brake fluid pressure corresponding to the stroke of the brake pedal 22 is generated in the primary chamber PC of the master cylinder 3. Further, the secondary piston 33 is urged by the hydraulic pressure generated in the primary chamber PC and moves forward in the cylinder portion 311, so that the secondary chamber SC also corresponds to the stroke of the brake pedal 22 (generated in the primary chamber PC). Brake fluid pressure (approximately the same as fluid pressure) is generated.

At this time, since the seal diameters of the third seal cup 34c and the fourth seal cup 34d with respect to the primary piston 36 are equal, the servo drive hydraulic pressure of the power hydraulic pressure source 7 supplied to the drive chamber DC and the primary chamber PC are generated. The brake fluid pressure is almost equal.
Before the stroke amount of the brake pedal 22 reaches the first predetermined value until it reaches the first predetermined value, the wheel cylinders WC1 and WC2 on the front wheels FL, FR side are liquidated according to the stroke amount of the brake pedal 22. A pressure braking force is supplied, and only the regenerative braking force by the regenerative braking device A is continuously applied to the rear wheels RL and RR (indicated by B in FIG. 5 and denoted by F in FIG. 6).

  Control of the vehicle braking force in accordance with the stroke amount of the brake pedal 22 in this state is performed by adjusting the hydraulic braking force on the front wheels FL and FR by changing the servo driving hydraulic pressure to the driving chamber DC. Is called. In this state, even when the regenerative braking force to the rear wheels RL and RR increases or decreases, the vehicle braking force is controlled by increasing or decreasing the hydraulic braking force to the front wheels FL and FR.

  The servo drive hydraulic pressure supplied to the drive chamber DC is also introduced into the compensation chamber CC via the both-part connecting holes 434. Further, the pressure receiving area of the input piston 43 in the drive chamber DC and the pressure receiving area of the large diameter portion 432 of the input piston 43 in the compensation chamber CC are set to be equal. As a result, the front surface of the input piston 43 receives the servo drive hydraulic pressure in the drive chamber DC, but the input piston 43 is urged in the front-rear direction by the servo drive hydraulic pressure from the power hydraulic pressure source 7. Not to be.

(Iii) Operation when the stroke amount of the brake pedal 22 is greater than or equal to the first predetermined value The stroke amount of the brake pedal 22 further increases, and the brake ECU 21 causes the stroke amount of the brake pedal 22 to reach the first predetermined value (difference) When it is determined that the hydraulic pressure between the primary chamber PC before and after the pressure valve 91 and the rear wheel RL, RR side wheel cylinders WC3, WC4 has reached a predetermined differential pressure (indicated by point q in FIG. 5). ), The power hydraulic pressure source 7 is controlled based on the detected value by the pedal stroke sensor 22a and the detected values by the pressure sensors 78 and 92, and the servo driving hydraulic pressure corresponding to the stroke amount of the brake pedal 22 is generated in the driving chamber DC. (Shown in FIG. 4).
As a result, according to the stroke amount of the brake pedal 22, the hydraulic pressures of the rear wheel RL, RR side wheel cylinders WC3, WC4 increase together with the hydraulic pressures of the front wheel FL, FR side wheel cylinders WC1, WC2.
As a result, as indicated by C in FIG. 5, the stroke of the brake pedal 22 is maintained while the hydraulic braking force applied to the rear wheels RL, RR is maintained lower than the hydraulic braking force applied to the front wheels FL, FR. Accordingly, the hydraulic braking forces of the front and rear wheels FL, FR, RL, RR are all increased.

In C shown in FIG. 5, it is assumed that the braking force applied to the rear wheels RL and RR is lower than the braking force applied to the front wheels FL and FR even when the regenerative braking force and the hydraulic braking force are included. is doing.
Thereafter, only the hydraulic braking by the hydraulic brake device B functions for the front wheels FL and FR, and the regenerative braking by the regenerative braking device A and the hydraulic brake device B for the rear wheels RL and RR. Both of the hydraulic brakes according to the above function (shown by C in FIG. 5 and indicated by G in FIG. 6). As a result, the braking force applied to the rear wheels RL and RR is supplemented by the regenerative braking force by the amount that the hydraulic braking force applied to the rear wheels RL and RR is set lower than the hydraulic braking force applied to the front wheels FL and FR. .

(2) when the vehicle power supply is defective in operation the hydraulic brake device B when the vehicle electric power source fail, after the input piston 43 moves forward by the amount of movement S _0, directly press the input piston 43 is the primary piston 36 When the primary piston 36 moves forward in the cylinder portion 311, hydraulic pressure is generated in the primary chamber PC and the secondary chamber SC. At this time, since the differential pressure valve 91 is in a non-energized state (opened state), the primary chamber PC communicates with the rear wheel RL, RR side wheel cylinders WC3, WC4, and the rear wheel RL, RR side wheel cylinders WC3, WC4. Is not suppressed with respect to the hydraulic pressure in the primary chamber PC. As a result, only the hydraulic braking force by the hydraulic brake device B is applied to the front wheel FL, FR side and rear wheel RL, RR side wheel cylinders WC1, WC2, WC3, WC4.

  The stroke amount of the brake pedal 22 (second point in the present embodiment) at the time when supply of servo drive hydraulic pressure to the drive chamber DC is started (point p in FIG. 5) by the drive power system of the power hydraulic pressure source 7. (Predetermined value) is the ideal distribution of the braking force applied to the front and rear wheels FL, FR, RL, RR by the characteristic of the regenerative braking force applied to the rear wheels RL, RR by the regenerative braking device A (A in FIG. 5). It is conceivable to make the value approximate to a diagram. For example, it is conceivable that supply of servo drive hydraulic pressure to the drive chamber DC is started at a timing such that the point p in FIG. 5 does not protrude upward from the ideal distribution diagram.

  Further, in the rear wheel RL and the RR side wheel cylinders WC3 and WC4, the stroke amount of the brake pedal 22 (first predetermined value in the present embodiment) at the time when the increase of the hydraulic pressure starts via the differential pressure valve 91 is the brake A value such that the characteristics of the vehicle braking force including hydraulic braking and regenerative braking (C in FIG. 5) do not protrude upward in the ideal distribution diagram in a region where the stroke amount of the pedal 22 is greater than the first predetermined value. It is conceivable to set to

  According to the present embodiment, until the stroke amount of the brake pedal 22 reaches the first predetermined value, the hydraulic pressure is not generated in the rear wheel RL and the RR side wheel cylinders WC3 and WC4 by the operation of the differential pressure valve 91. By making the hydraulic braking force to the rear wheels RL and RR smaller than the hydraulic braking force to the front wheels FL and FR, the regenerative braking force can be sufficiently generated in the rear wheels RL and RR in the initial braking.

Further, until the stroke amount of the brake pedal 22 reaches the first predetermined value, when the regenerative braking force increases or decreases, the vehicle braking force is adjusted by controlling the hydraulic pressure of the front wheel FL, FR side wheel cylinders WC1, WC2. I tried to do it. Thus, the rear wheels RL and the wheel cylinders WC3 and WC4 on the RR side have the hydraulic pressure of the rear wheel RL without being lower than the hydraulic pressure of the primary chamber PC or the hydraulic pressure of the secondary chamber SC by more than the set pressure of the differential pressure valve 91. , RR side regenerative braking force increase / decrease can be compensated.
In addition, the hydraulic brake device B that executes the regenerative cooperative control can be formed only by providing one differential pressure valve 91 between the rear wheel RL, RR side wheel cylinders WC3, WC4 and the primary chamber PC. The control method can also be simplified.

  In addition, after the stroke amount of the brake pedal 22 reaches the first predetermined value, the hydraulic braking force applied to the rear wheels RL and RR is lower than the hydraulic braking force applied to the front wheels FL and FR due to the operation of the differential pressure valve 91. In accordance with the stroke amount of the brake pedal 22, both the hydraulic pressures of the front wheel FL and FR wheel cylinders WC1 and WC2 and the hydraulic pressures of the rear wheel RL and RR wheel cylinders WC3 and WC4 are increased. By avoiding the preceding lock at the rear wheels RL and RR, the braking force distribution of the front and rear wheels FL, FR, RL and RR can be approximated to the ideal distribution.

Further, an input piston 43 that is connected to the brake pedal 22 and is movable in the cylinder portion 311 is provided behind the primary piston 36. When the brake pedal 22 is not operated, the primary piston 36 and the input are input. An interval S ₀ corresponding to the second predetermined value is provided between the piston 43 and the stroke amount of the brake pedal 22.
Thereby, in the initial braking, the input piston 43 does not contact the primary piston 36 even if the input piston 43 moves forward in the cylinder portion 311 until the stroke amount of the brake pedal 22 reaches the second predetermined value. The invalid stroke region of the brake pedal 22 that does not generate hydraulic pressure in the chamber PC can be reliably formed.
Further, the pressure reducing means of the rear wheel RL, RR side wheel cylinders WC3, WC4 is the differential pressure valve 91 that is controlled by the brake ECU 21, so that the rear wheel RL, RR is applied to the rear wheels RL, RR according to the stroke amount of the brake pedal 22. The hydraulic braking force can be applied with high accuracy.

In addition, a check valve 91a that allows only the flow of brake fluid from the rear wheel RL, RR side wheel cylinders WC3, WC4 to the primary chamber PC is provided in parallel with the differential pressure valve 91.
Thereby, when the hydraulic pressure of the primary chamber PC becomes lower than the hydraulic pressure of the rear wheels RL and RR side wheel cylinders WC3 and WC4 by returning the stroke of the brake pedal 22, the rear wheel is set via the check valve 91a. The brake fluid in the RL and RR side wheel cylinders WC3 and WC4 is returned to the primary chamber PC.
Therefore, regardless of the operating state of the differential pressure valve 91, the hydraulic pressures of the rear wheel RL and the RR side wheel cylinders WC3 and WC4 can be reduced in accordance with a decrease in the stroke amount of the brake pedal 22.

<Modification 1 of Embodiment 1>
FIG. 7 shows a first modification of the decompression means in the first embodiment. In this modification, a residual pressure valve 94 is provided between the primary chamber PC on the main line Lp and the ABS actuator 5 in place of the linear valve 91 as the pressure reducing means. In the residual pressure valve 94, the valve body 942 is urged against the valve seat 943 by an elastic member 941 having a predetermined set load, and the brake fluid from the primary chamber PC to the rear wheel RL, RR side wheel cylinders WC3, WC4. Only the flow of is allowed.

  The residual pressure valve 94 is closed until the hydraulic pressure on the primary chamber PC side reaches a predetermined pressure (maximum differential pressure) by the urging force of the elastic member 941, and the hydraulic pressure is applied to the rear wheel RL and the RR side wheel cylinders WC3 and WC4. Does not occur. The residual pressure valve 94 is opened when the hydraulic pressure on the primary chamber PC side reaches the maximum differential pressure, and thereafter, the hydraulic pressure of the rear wheel RL, RR side wheel cylinders WC3, WC4 is changed to the hydraulic pressure on the primary chamber PC side. In contrast, the maximum differential pressure can be lowered. The maximum differential pressure is determined by the hydraulic pressure on the primary chamber PC side and the hydraulic pressures on the rear wheel RL and RR side wheel cylinders WC3 and WC4 (at this time point) when the stroke amount of the brake pedal 22 reaches the first predetermined value. 0).

  As shown in FIG. 7, between the rear wheel RL, RR side wheel cylinders WC3, WC4 and the primary chamber PC of the main line Lp, the rear wheel is arranged in parallel with the residual pressure valve 94 in the same manner as in the first embodiment. A check valve 94a that allows only the flow of the brake fluid from the RL and RR side wheel cylinders WC3 and WC4 to the primary chamber PC is provided.

<Modification 2 of Embodiment 1>
FIG. 8 shows a second modification of the decompression means in the first embodiment. In this modification, an on-off valve 95, which is a normally open electromagnetic valve, is provided in parallel with the residual pressure valve 94 and the check valve 94a shown in FIG. The on / off valve 95 is controlled by the brake ECU 21 to be closed when the hydraulic pressure of the rear wheel RL, RR side wheel cylinders WC3, WC4 is set lower than the hydraulic pressure of the primary chamber PC, and the rear wheel RL, RR side When the brake fluid of the wheel cylinders WC3 and WC4 is returned to the primary chamber PC, it is opened.

<Embodiment 2>
Next, based on FIG. 9 thru | or FIG. 11, the difference with respect to Embodiment 1 of hydraulic brake device B1 by Embodiment 2 of this invention is demonstrated.
As shown in FIG. 9, in the hydraulic brake device B1 according to the present embodiment, the primary chamber PC on the main line Lp and the differential pressure valve 91 are connected to the output line PL4 of the power hydraulic pressure source 7. In addition, an outflow conduit LC is formed, and an absorption reservoir 96 is formed on the outflow conduit LC. The absorption reservoir 96 is included in the brake actuator D1, and a movable body 962 is movably provided in a reservoir case 961 having a predetermined capacity.

  The moving body 962 is fluid-tightly fitted to the reservoir case 961, thereby forming a storage chamber 963 by one end surface (upper surface in FIG. 9) and the reservoir case 961, and the other end surface (FIG. 9 and the reservoir case 961 form a back pressure chamber 964. As shown in FIG. 9, the storage chamber 963 is connected to the primary chamber PC of the master cylinder 3, and the back pressure chamber 964 is connected to the drive chamber DC. An elastic spring 965 is interposed between the moving body 962 and the reservoir case 961, and the moving body 962 is biased toward the storage chamber 963 by the elastic spring 965.

  On the outflow pipe LC, a cut valve 97, which is a normally closed electromagnetic valve, is interposed between the primary chamber PC and the storage chamber 963. The cut valve 97 is connected to the brake ECU 21 and is controlled to be opened and closed by the brake ECU 21. In the cut valve 97, a check valve 97a that allows the flow of brake fluid from the storage chamber 963 to the primary chamber PC is formed in parallel. The check valve 97a opens when the cut valve 97 is closed and the brake fluid pressure in the primary chamber PC decreases, and has a function of returning the brake fluid in the storage chamber 963 to the primary chamber PC side.

Next, differences from the first embodiment relating to the operation method of the hydraulic brake device B1 according to the present embodiment will be described. In the present embodiment, unlike the case of the first embodiment, the distance S ₁ between the primary piston 36 and the input piston 43 when the brake pedal 22 is not stroked is determined for the stroke amount of the brake pedal 22. It is set so as to correspond to a value smaller than the second predetermined value in the first mode.

When the input piston 43 moves forward amount S ₁ or more, the front end of the input piston 43 abuts against the rear surface of the primary piston 36. Thereafter, the servo hydraulic pressure is not generated by the power hydraulic pressure source 7 until the stroke amount of the brake pedal 22 reaches the second predetermined value, and the primary piston 36 is directly pressed by the input piston 43. , Both move together (shown in FIG. 10). As a result, the second communication port 361 of the primary piston 36 passes through the third seal cup 34 c and the primary chamber PC is shut off from the reservoir tank 23.

  When the front end of the input piston 43 comes into contact with the rear surface of the primary piston 36, the brake ECU 21 opens the cut valve 97. Therefore, the brake in the primary chamber PC is moved forward by the primary piston 36 in the cylinder portion 311. The liquid flows into the storage chamber 963 of the absorption reservoir 96 against the urging force of the elastic spring 965. Thus, no hydraulic pressure is generated in the primary chamber PC regardless of the forward movement of the primary piston 36. Further, since no hydraulic pressure is generated in the primary chamber PC, the secondary piston 33 does not move forward, and no hydraulic pressure is generated in the secondary chamber SC. Therefore, no hydraulic brake is applied to the wheels FL, FR, RL, and RR.

At this time, it is desirable to make the set load of the secondary spring 35 larger than the compressive load of the primary spring 40 generated by the advance of the primary piston 36.
In this state, only the regenerative braking by the regenerative braking device A is performed on the driving wheels RL and RR continuously from the start of the stroke of the brake pedal 22.

  When the stroke amount of the brake pedal 22 further increases and the brake ECU 21 determines that the stroke amount of the brake pedal 22 has reached the second predetermined value, based on the detection value by the pedal stroke sensor 22a and the detection value by the pressure sensor 78. In the driving force power system of the power hydraulic pressure source 7, a servo driving hydraulic pressure corresponding to the stroke amount of the brake pedal 22 is generated and the servo driving hydraulic pressure is supplied to the driving chamber DC (shown in FIG. 11).

The servo drive hydraulic pressure supplied to the drive chamber DC urges the primary piston 36 of the master cylinder 3 to advance the primary piston 36 in the cylinder portion 311. When the servo drive hydraulic pressure is supplied to the drive chamber DC, the primary piston 36 is separated from the input piston 43 and moves forward in the cylinder portion 311.
At this time, since the servo driving hydraulic pressure of the power hydraulic pressure source 7 is also supplied to the back pressure chamber 964 of the absorption reservoir 96 via the outflow line LC, the back pressure chamber of the moving body 962 in the reservoir case 961 is provided. Movement in the 964 direction is prevented. Accordingly, no more brake fluid flows from the primary chamber PC into the storage chamber 963.
Thereby, in the primary chamber PC of the master cylinder 3, the brake fluid pressure according to the stroke of the brake pedal 22 is generated. However, as described above, the hydraulic pressure is not generated in the rear wheel RL and the RR side wheel cylinders WC3 and WC4 by the operation of the differential pressure valve 91.

Further, since the hydraulic pressure is generated in the primary chamber PC, the secondary piston 33 also moves forward in the cylinder portion 311 to generate the brake hydraulic pressure corresponding to the stroke amount of the brake pedal 22 in the secondary chamber SC. Thereby, the braking force by the hydraulic brake can be applied to the front wheels FL, FR.
Further, when the driving force power system of the power hydraulic pressure source 7 starts to generate the servo driving hydraulic pressure, the cut valve 97 is closed to transfer the primary chamber PC to the storage chamber 963 of the absorption reservoir 96. The inflow of the brake fluid may be blocked.

Thereafter, when the stroke amount of the brake pedal 22 reaches the first predetermined value, the hydraulic pressure is also applied to the rear wheels RL, RR side wheel cylinders WC3, WC4, as in the case of the first embodiment.
Further, in the hydraulic brake device B1, when the vehicle power supply fails, the cut valve 97 is closed, so that the brake fluid is prevented from flowing from the primary chamber PC into the storage chamber 963, and the liquid is supplied to the primary chamber PC. Since pressure is generated, a hydraulic braking force can be applied to the wheels FL, FR, RL, and RR.

<Other embodiments>
The present invention is not limited to the above-described embodiments, and can be modified or expanded as follows.
The present invention can be applied not only to a hybrid vehicle but also to an electric vehicle (EV).
Further, the rear wheel RL, RR side wheel cylinders WC3, WC4 may be connected to the secondary chamber SC, and the front wheel FL, FR side wheel cylinders WC1, WC2 may be connected to the primary chamber PC. In this case, needless to say, the differential pressure valve 91 and the check valve 91a or the residual pressure valve 94, the check valve 94a and the on / off valve 95 are provided on the main line Ls.
Further, the operation amount of the brake operation member may be detected by the stroke amount of the push rod 24 or the stroke amount of the input piston 43 of the master cylinder 3.

Further, during the period from when the stroke amount of the brake pedal 22 reaches the second predetermined value to when it reaches the first predetermined value (section indicated by B in FIG. 5), the stroke amount of the brake pedal 22 depends on the stroke amount. Thus, a slight hydraulic pressure lower than the hydraulic pressure generated in the front wheel FL, FR side wheel cylinders WC1, WC2 may be applied to the rear wheel RL, RR side wheel cylinders WC3, WC4. That is, the section indicated by B in FIG. 5 may be inclined slightly upward.
In the above embodiment, the present invention is applied to a rear wheel drive vehicle. However, although the present invention is a front and rear wheel drive vehicle, it can also be applied to a vehicle in which the regeneration capability of the rear wheels is higher than the regeneration capability of the front wheels. Even in this case, the same effect as the above-described embodiment is obtained (see FIG. 12).

  In the drawing, 3 is a master cylinder, 19 is a hybrid ECU (regenerative braking control means), 21 is a brake ECU (hydraulic braking control means), 22 is a brake pedal (brake operation member), 22a is a pedal stroke sensor (brake operation amount). Detection means), 33 is a secondary piston, 36 is a primary piston, 43 is an input piston, 91 is a differential pressure valve, 91a and 94a are check valves, 94 is a residual pressure valve (differential pressure valve), 311 is a cylinder portion, and A is a regenerative brake Device (regenerative braking unit), B and B1 are hydraulic brake devices, FL and FR are front wheels, RL and RR are rear wheels, PC is a primary chamber (primary hydraulic chamber), and SC is a secondary chamber (secondary hydraulic chamber). , WC1 and WC2 are front wheel side wheel cylinders, and WC3 and WC4 are rear wheel side wheel cylinders.

Claims (5)

It is applied to a vehicle having a brake piping of two front and rear systems, and having a regenerative braking unit that applies a regenerative braking force to the rear wheels,
A primary piston movable in the cylinder portion, and a secondary piston disposed in front of the primary piston and movable in the cylinder portion, and a primary hydraulic chamber is provided between the primary piston and the secondary piston. A secondary hydraulic pressure chamber is formed in front of the secondary piston, the primary hydraulic pressure chamber is connected to one of a front wheel side wheel cylinder and a rear wheel side wheel cylinder, and the secondary hydraulic pressure chamber is The primary hydraulic pressure chamber is connected to the other of the front wheel side wheel cylinder and the rear wheel side wheel cylinder, and the primary piston is urged to move forward, thereby generating a hydraulic pressure in the primary hydraulic pressure chamber and the primary hydraulic pressure. The secondary piston is moved forward by the hydraulic pressure generated in the chamber. Hydraulic said secondary hydraulic chamber is generated by a master cylinder for applying braking force to front and rear wheels,
Brake operation amount detection means for detecting the operation amount of the brake operation member;
Provided between the rear wheel side wheel cylinder and the primary hydraulic chamber or the secondary hydraulic chamber, the liquid in the primary hydraulic chamber or the secondary hydraulic chamber with respect to the hydraulic pressure of the rear wheel side cylinder A differential pressure valve that opens when the pressure is higher than a predetermined set pressure; and
Between the start of operation of the brake operation member and the opening of the differential pressure valve, the regenerative braking unit applies a regenerative braking force corresponding to the operation amount detected by the brake operation amount detection means to the rear wheel. Regenerative braking control means to be applied;
A vehicle braking device comprising:   After the operation of the brake operation member is started, the operation amount of the brake operation member reaches a second predetermined value that is smaller than a first predetermined value that is an operation amount of the brake operation member that opens the differential pressure valve. The regenerative braking control means until the operation amount of the brake operation member reaches the second predetermined value until the operation amount of the brake operation member reaches the second predetermined value. The braking device for a vehicle according to claim 1, wherein a braking force is applied to the rear wheel. An input piston that is connected to the brake operation member and is movable in the cylinder portion is provided behind the primary piston.
The predetermined interval corresponding to the second predetermined value is provided between the primary piston and the input piston when the brake operation member is not operated. Vehicle braking system.   Between the rear wheel side wheel cylinder and the primary hydraulic pressure chamber or the secondary hydraulic pressure chamber, the rear wheel side wheel cylinder is directed in parallel with the differential pressure valve to the primary hydraulic pressure chamber or the secondary hydraulic pressure chamber. The vehicle braking device according to any one of claims 1 to 3, further comprising a check valve that allows only a flow of brake fluid.   Increase / decrease in the regenerative braking force of the rear wheel by the regenerative braking control means when the operation amount of the brake operation member is less than a first predetermined value that is the operation amount of the brake operation member that opens the differential pressure valve. 5. The vehicle braking device according to claim 4, further comprising a hydraulic braking control means for increasing or decreasing the hydraulic braking force of the front wheel according to the above.

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