JP2003118551A - Brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake device for a vehicle requiring no excessive power for braking operation and capable of exhibiting a desired braking force by preventing un-uniformity of hydraulic fluid pressure between a front wheel side and rear wheel side. SOLUTION: This brake device for the vehicle comprises a master cylinder, a hydraulic fluid reservoir, a front wheel side fluid pressure source, a rear wheel side fluid pressure source, a front wheel side braking means, a rear wheel side braking means, a front wheel side fluid pressure system for supplying fluid pressure from the front wheel side fluid pressure source to the front wheel side braking means, a rear wheel side fluid pressure system for supplying fluid pressure from the rear wheel side fluid pressure source to the rear wheel side braking means, control valves disposed in the front wheel side fluid pressure system and the rear wheel side fluid pressure system and adjusting the fluid pressure of respective fluid pressure systems, a common driving source for simultaneously driving the front wheel side fluid pressure source and the rear wheel side fluid pressure source, and a braking mechanism for applying a braking force to each of the front wheels and the rear wheels. The rear wheel side fluid pressure system is provided with a fluid absorbing means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular brake device that operates by hydraulic pressure.

[0002]

2. Description of the Related Art An example of such a brake device is disclosed in Japanese Patent Laid-Open No. 8-150911.

In this brake device, in order to operate the wheel cylinder, a master cylinder for generating a hydraulic pressure in response to a driver's operation and a pump for generating a hydraulic pressure regardless of the driver's operation are provided. In addition to supplying the master cylinder pressure generated according to the driver's operation to the wheel cylinder, the hydraulic pressure from the pump is supplied to the wheel cylinder independently of the driver's operation. ing.

There are usually two hydraulic pressure supply systems to the wheel cylinders, one for the left front wheel and one for the right rear wheel,
It is so-called X piping, with one system for the right front wheel and the left rear wheel. The pump is provided in each system and is driven by a common drive source. Further, each hydraulic pressure supply system is provided with a control valve for controlling the hydraulic pressure of each system.

[0005]

In the brake device described in the above publication, the hydraulic system to the wheel cylinder is the X pipe as described above, but the invention is not limited to this.
It is also conceivable to use so-called front-rear piping, in which the hydraulic system has one system for each of the front wheel side and the rear wheel side. However, in this case, there are the following problems.

That is, since a large load is applied to the front wheels during braking of the vehicle, the wheel cylinder capacity is usually set such that the front wheel capacity is larger than the rear wheel capacity.
In this case, if the pump capacity provided for each hydraulic system on the front and rear wheels is set according to the wheel cylinder capacity on the front wheel side, the hydraulic capacity that can be supplied to the hydraulic system on the rear wheel side is set to the wheel cylinder. Is overkill for capacity,
It becomes necessary to operate the control valve provided in the hydraulic system on the rear wheel side. As a result, electric power is required to operate the control valve, and vibrations, noise, and hydraulic pressure fluctuations associated with the operation of the control valve may make the driver feel uncomfortable.

Further, when the pumps are set to have the required capacities for the front wheel side and the rear wheel side, respectively, these pumps are driven by a common drive source, so that imbalance occurs when driving the pumps. This may cause vibration.

An object of the present invention is to propose a vehicular brake device that solves the above problems.

[0009]

That is, a brake device according to a first aspect of the invention is a master cylinder, a hydraulic fluid reservoir, a front wheel side hydraulic pressure source, a rear wheel side hydraulic pressure source, and front wheel side braking means. A rear wheel side braking means, a front wheel side hydraulic system for supplying hydraulic pressure from the front wheel side hydraulic pressure source to the front wheel side braking means, and a hydraulic pressure from the rear wheel side hydraulic pressure source for the rear wheel side A rear wheel hydraulic system for supplying to the side braking means, a control valve provided in the front wheel hydraulic system and the rear wheel hydraulic system for adjusting the hydraulic pressure of each hydraulic system, and the front wheel hydraulic system. In a vehicle brake device comprising a common drive source for driving a pressure source and the rear wheel side hydraulic pressure source, and a braking mechanism for applying a braking force to each of the front wheels and the rear wheels, a hydraulic pressure is applied to the rear wheel side hydraulic system. It is characterized in that a quantity absorbing means is provided.

In the braking device according to the second aspect of the present invention, the rear wheel side hydraulic system is located immediately downstream of the discharge port side of the rear wheel side hydraulic pressure source and the rear wheel side hydraulic pressure source and the master cylinder. And a check valve for suppressing the flow from the master cylinder side to the rear wheel side hydraulic pressure source side, and the liquid amount absorbing means is provided at the discharge port of the rear wheel side hydraulic pressure source. It is arranged between the check valve and the check valve.

A braking device according to a third aspect of the present invention is characterized by being applied to a vehicle further including an electric motor for driving at least one of front wheels and rear wheels.

A braking device according to a fourth aspect of the present invention further comprises an electric motor for driving the rear wheels, and is applied to a vehicle for braking the rear wheels by a regenerative operation of the electric motor. is there.

[0013]

In the braking device according to the first aspect of the invention, the hydraulic system on the rear wheel side is provided with the liquid amount absorbing means,
During brake operation, this fluid amount absorbing means temporarily absorbs excess brake fluid to reduce the hydraulic pressure in the rear wheel side hydraulic system, thereby reducing the hydraulic pressure in the wheel cylinders on the rear wheel side, The hydraulic pressure in the side wheel cylinder is made approximately equal. As a result, in the hydraulic system on the rear wheel side, the frequency of operating the pressure reducing valve to reduce the hydraulic pressure is also reduced, the power consumption for operating the pressure reducing valve is suppressed, and the operation of the valve and It is possible to suppress the accompanying vibration of the hydraulic pressure, and further, it is possible to prevent the durability of the solenoid that drives the valve from being deteriorated and the occurrence of operating noise.

In the brake device according to the second aspect of the present invention, the rear wheel hydraulic system is located immediately downstream of the discharge side of the rear wheel hydraulic pressure source and the rear wheel hydraulic pressure source and the master cylinder. And a check valve for suppressing the flow from the master cylinder side to the rear wheel side hydraulic pressure source side, and the liquid amount absorbing means is provided at the discharge port of the rear wheel side hydraulic pressure source. And the check valve. By arranging the liquid amount absorbing means in this way, the check valve is provided on the master cylinder side of the liquid amount absorbing means. Therefore, when the driver of the vehicle performs a normal braking operation, the hydraulic pressure on the master cylinder side is not reduced as it is due to the absorption of the brake fluid by the fluid amount absorbing means, and the operation of the fluid amount absorbing means operates. It is possible to prevent the braking operation of the person from being affected.

The braking device according to the third aspect of the invention is applied to a so-called hybrid vehicle or electric vehicle in which at least one of the front wheels and the rear wheels is driven by an electric motor. In this case, it is possible to suppress the electric power consumption due to the driving of the control valve in the braking operation, so that it is possible to improve the energy efficiency of the vehicle.

Further, in a braking device according to a fourth aspect of the present invention, the device is driven by the hybrid vehicle or the electric vehicle, particularly the rear wheels, by an electric motor, and
The braking of the rear wheels will be applied to the vehicle in which the regenerative operation of this electric motor is performed. In this case, it is possible to suppress the adjustment of the hydraulic pressure in the hydraulic system on the rear wheel side by the control valve, so that the hydraulic pressure fluctuation in the hydraulic system on the rear wheel side is also suppressed, and the braking of the driver is thereby suppressed. The braking force according to the operation can be realized without giving the driver a feeling of strangeness. Further, the chances of control for adjusting the regenerative braking force corresponding to the fluid pressure fluctuation are reduced, so that the stability of the regenerative cooperative control can be improved.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 schematically shows the configuration of a first embodiment of a brake device according to the present invention. The illustrated brake device is capable of anti-skid control and traction control in addition to normal brake control.

In the figure, 1 is a brake pedal, 2 is a hydraulic fluid booster, 3 is a master cylinder, 4 is a brake fluid (working fluid) reservoir, 5FR, 5FL, 5RR and 5RL are wheel cylinders (braking mechanism), and 6 is Front wheel hydraulic piping (hydraulic system), 7 is rear wheel hydraulic piping, and 8 is a pressure sensor. The master cylinder 3 is connected to the brake pedal 1 via the hydraulic fluid booster 2, and when the driver depresses the brake pedal 1, the pedal depression force increased by the hydraulic fluid booster 2 acts on the master cylinder 3. Master cylinder 3
At, brake fluid pressure is generated. Two hydraulic pipes, that is, a front wheel side hydraulic pipe 6 and a rear wheel side hydraulic pipe 7 are connected to the master cylinder 3. Front wheel side hydraulic piping 6 is wheel cylinders 5FR and 5FL on the front wheel side and rear wheel side hydraulic piping
7 is connected to the wheel cylinders 5RR and 5RL on the rear wheel side, respectively, whereby the brake fluid pressure generated in the master cylinder 3 is transmitted to each wheel cylinder to perform a braking operation.

In each hydraulic pipe, a pump is applied to each wheel cylinder regardless of the brake fluid pressure generated in the master cylinder 3 according to the driver's operation or the driver's operation.
In order to adjust the brake fluid pressure generated at 9 and 10, gate valves 11 and 12, suction valves 13 and 14, pressure increasing valves 15, 16 and 17, 18,
Pressure reducing valves 19, 20 and 21, 22, dampers 23, 24, and check valves (check valves) 25-30 and 31-36 are provided, respectively. The pumps 9 and 10 are appropriately driven by a single motor 37 in response to a command from a controller 38 described later.

The gate valves 11 and 12 are two-position solenoid valves for controlling the supply of hydraulic pressure (master cylinder pressure) from the master cylinder 3 to the wheel cylinders 5FR, 5FL and 5RR, 5RL, respectively, and are usually (Energizing the solenoid
When the traction control is performed as will be described later, the solenoid is driven and controlled (energized) in response to a command from the controller 38, which will be described later, to close the master cylinder pressure. Shut off the supply to each wheel cylinder. The intake valves 13 and 14 are also two-position solenoid valves, but are normally in a closed state as opposed to the gate valves 11 and 12, and the communication between the master cylinder side and the upstream side of the pump 9 or the pump 10 is cut off. However, when the traction control described later is performed, the controller
An opening operation is performed by a solenoid that is driven and controlled according to a command from 38, and communication between the brake fluid reservoir 4 and the upstream sides of the pumps 9 and 10 is permitted via the master cylinder 3. The check valves 25 and 31 arranged in parallel with the gate valves 11 and 12, respectively, prevent the brake fluid discharged from the discharge ports of the gate valves 11 and 12 from flowing back to the master cylinder 3 side.

Pressure increasing valves 15, 16 and 17, 18, pressure reducing valves 19, 20
Reference numerals 21, 22 are provided for performing anti-skid control and traction control in the brake device, and both are 2-position solenoid valves. Increasing valve
15-18 are normally open, while pressure reducing valves 19-22 are
Normally closed. At the time of anti-skid control and traction control, each valve is operated by driving and controlling the solenoid of each valve in response to a command from the controller 38. The check valves 26, 27, 32, and 33 arranged in parallel with the pressure increasing valves 15 to 18 have brake fluid of the pressure increasing valves 15 to 18 respectively.
Prevents flow to the wheel cylinder side without passing through ~ 18.

Here, with the pressure increasing valves 15 to 18 open, the pressure reducing valve
When 19 to 22 are closed, the hydraulic pressure from the master cylinder 3 or the pumps 9 and 10 is supplied to each wheel cylinder, and when the pressure increasing valves 15 to 18 are closed from this state, When the wheel cylinder pressure is maintained and the pressure reducing valves 19 to 22 are opened from this state, each wheel cylinder pressure is applied to the brake fluid reservoir.
4 and the dampers 23 and 24 are returned to the decompression mode.

The pumps 9 and 10 pressurize the hydraulic fluid from the brake fluid reservoir 4 sucked through the shutoff valves 13 and 14, respectively, to supply the hydraulic fluid to the wheel cylinders, and the hydraulic pipes 6 and 7 respectively. It operates to return the brake fluid of the above to the master cylinder 3 side, and its capacity (discharging amount)
Is set according to the brake fluid pressure (wheel cylinder pressure) required for braking the front wheels and the rear wheels. The check valves 28, 29, 30 and 34, 35, 36 provided in front of and behind the respective pumps pass through the respective pumps 9, 10 and then the master cylinder 3
Prevents back flow of brake fluid returning to the side. The dampers 23, 24 are provided to adjust the amount of fluid in the hydraulic pressure pipes 6, 7 and the hydraulic pressure resulting therefrom, and when the amount of brake fluid in each pipe becomes excessive, excess Are absorbed in each damper.

In the illustrated brake device, in order to operate each of the above-mentioned components to perform anti-skid control and traction control, each component is detected according to the output from the wheel speed sensor 39 for detecting the wheel speed. There is provided a controller 38 for controlling the operation of.

In the brake operation by the driver, the pedaling force applied to the brake pedal 1 is increased by the booster 2, and the master cylinder 3 generates a master cylinder pressure corresponding to the pedaling force. Here, in the state shown in FIG. 1, the gate valves 11 and 12, the intake valves 13 and 14, and the pressure increasing valve.
15 to 18 and pressure reducing valves 19 to 22 are all inactive (energization to the solenoid is OFF), and master cylinder 3 increases pressure increasing valve 15
The flow of the hydraulic fluid to 18 is allowed because the gate valves 11 and 12 are open. Further, the pressure increasing valves 15 to 18 are all open, while the pressure reducing valves 19, 20 and 21, 22 are all closed. Therefore, when the driver depresses the brake pedal 1, the master cylinder pressure generated in the master cylinder 3 is reduced by the pressure increasing valves 15, 16 and 17, 18 of the front wheel side hydraulic pipe 6 and the rear wheel side hydraulic pipe 7, respectively. Valves 19, 20 and
Through 21 and 22, each wheel cylinder 5FR, 5FL, 5RR, 5RL
Then, the braking force corresponding to the pressure in the master cylinder 3 (master cylinder pressure) according to the driver's operation is applied to each wheel.

Next, in the illustrated braking device, anti-skid control is performed when the driver is in a state in which the wheels are likely to lock during braking. That is,
When the controller 38 detects the slip state of the wheels based on the detection value from the wheel speed sensor 39 provided for each wheel, the pressure increasing valves 15 to 18 and the pressure reducing valves 19 to 22 are appropriately driven by a command from the controller 38. Then, the wheel cylinder pressure is controlled until the slip amount of the wheel decreases to a predetermined value by creating each of the pressure increasing, holding, and pressure reducing modes described above.

That is, by turning on the solenoids of the pressure increasing valves 15-18 and the pressure reducing valves 19-22, the pressure increasing valves 15, 16 and 17, 18 are closed, while the pressure reducing valves 19, 20 and 21, 22 are opened. . As a result, each wheel cylinder 5FR, 5FL, 5RR, 5
The hydraulic fluid in RL is discharged to the reservoirs 23 and 24, respectively, whereby the wheel cylinder pressure is reduced, and as a result, the braking force of the wheels is reduced and the slip amount is reduced. The hydraulic fluid in each reservoir 23, 24 is
It is returned to the master cylinder 3 side by 9 and 10 (pressure reduction mode).

After that, when the slip amount of the wheel has decreased to a predetermined value, the solenoids of the pressure reducing valves 19 to 22 are turned off while the pressure increasing valves 15 to 18 are kept closed, and the pressure reducing valve 19 to By closing 22 to control to maintain the current wheel cylinder pressure, each wheel cylinder 5F
If the wheel cylinder pressures of R, 5FL, 5RR, and 5RL are maintained (holding mode), and if the slip amount of the wheels falls below a predetermined value, turn off the solenoids of pressure increase valves 15 to 18 and increase the pressure increase valve 15 ~ 18 is opened and the pressure reducing valves 19 to 22 are kept closed, and control is performed to increase the hydraulic pressure this time to increase the wheel cylinder pressure of each wheel cylinder 5FR, 5FL, 5RR, 5RL ( Boosting mode).

Further, in the present brake device, traction control is performed when the drive wheels slip due to a rapid increase in engine torque, such as when the vehicle suddenly starts or suddenly accelerates. In this case, when the controller 38 detects the slip state of the wheels based on the detection value from the wheel speed sensor 39 provided for each wheel, each wheel cylinder 5F
Brake fluid pressure needs to be supplied to R, 5FL, 5RR, and 5RL, but in a situation where traction control is required, the driver's braking operation is not executed, and therefore master cylinder pressure is not generated either. , The following operations are performed.

That is, the gate valves 11 and 12 and the intake valve 1
The solenoids 3 and 14 are turned on to shut off the supply of hydraulic fluid from the master cylinder 3 for the gate valves 11 and 12, and the reservoir 4 side and the pumps 9 and 10 for the intake valves 13 and 14.
Communication with the upstream side is possible. As a result, a pump that is appropriately driven according to a command from the controller 38
The brake fluid pressure from 9 and 10 is supplied to the upstream side of the pressure increasing valves 15 to 18. Then, for the wheel in which the slip state is detected, the pressure increasing valves 15 to 18 are appropriately opened, and the pressure reducing valves 19 to 22 are appropriately closed. By setting the pressure increasing mode described above, the wheel cylinders 5FR, 5FL, Brake fluid pressure is supplied to either 5RR or 5RL to control the wheel cylinder pressure until the slip amount of the wheel drops to a specified value.

Thereafter, as the slip amount of the wheel is suppressed, the pressure increasing valves 15-18 and the pressure reducing valves 19-22 are appropriately controlled,
By creating the holding mode and decompression mode described above,
It controls the wheel cylinder pressure of each wheel cylinder 5FR, 5FL, 5RR, 5RL.

Therefore, even if the driver does not perform a braking operation, a braking force is generated on the driving wheels, thereby reducing the rotational speed of the wheels and eliminating the slip state.

In the illustrated braking device, a reservoir 40 is further provided in the rear wheel side hydraulic pipe 7. The reservoir 40 temporarily absorbs an excessive amount of the brake fluid flowing through the rear wheel hydraulic pipe 7. As a result, the hydraulic pressure in the rear wheel side hydraulic pipe 7 is reduced, and the pressure reducing valves 21 and 22 on the rear wheel side are operated to reduce the frequency of the pressure reducing mode.

Further, the reservoir 40 is arranged between the discharge side of the pump 10 and the check valve 34 provided immediately downstream thereof. This means that the reservoir 40 is provided in the middle of the flow path of the brake fluid discharged from the pump 10 toward the master cylinder 3, and the check valve 34 is provided on the side of the reservoir 40 close to the master cylinder 3. Means that. That is, the flow of the brake fluid from the master cylinder 3 does not directly flow into the reservoir 40. for that reason,
The brake fluid pressure in the master cylinder 3 is
It is possible to prevent the pressure from being reduced due to the absorption of the brake fluid by 0, and it is possible to prevent the operation of the reservoir 40 from affecting the braking operation of the driver.

FIG. 2 is a characteristic diagram schematically showing the relationship between the hydraulic pressure and the liquid amount in each of the front wheel side hydraulic piping and the rear wheel side hydraulic piping. Here, the solid line is the characteristic curve in the brake device according to the present invention, and the broken line is the characteristic curve in the conventional brake device.

As is apparent from the figure, in the brake device according to the present invention, the hydraulic pressure-fluid amount characteristic on the rear wheel side (rear wheel side hydraulic pipe) can be made substantially equal to that on the front wheel side.

FIG. 3 is a time chart showing the operation of the pump motor and the solenoid for driving the valve provided in the hydraulic pipe in the braking operation for each of the braking apparatus shown in FIG. 1 and the conventional braking apparatus. Here, FIG. 3 (a) shows a conventional braking device, and FIG. 3 (b) shows a braking device according to the present invention.

As described above, generally, in the brake device, the braking force on the front wheel side is set to be larger than that on the rear wheel side. Therefore, if the pump capacity is made the same for each system on the front wheel side and the rear wheel side, when supplying brake fluid pressure to each wheel cylinder without relying on the driver's braking operation like the above-mentioned traction control. , The brake fluid pressure supplied to the wheel cylinders 5RR and 5RL on the rear wheel side becomes larger than the originally required value.

In the figure, the ON-OFF operation of the solenoid for driving each of the control valve, the rear-wheel side shutoff valve and the rear-wheel side pressure reducing valve in the braking operation is shown, but as shown in FIG. , In the case of the conventional brake device, in order to reduce the brake fluid pressure supplied to the wheel cylinders on the rear wheel side, a pulsed signal is repeatedly applied to the solenoid of the rear wheel side pressure reducing valve as shown in the figure to turn it on repeatedly. -The pressure is reduced by turning it off. Therefore, the vibrations associated with the operation of the pressure reducing valve and the vibrations in the hydraulic pressure in the rear-wheel-side hydraulic piping are generated.

On the other hand, in the brake device according to the present invention, as described above, the excessive brake fluid pressure is reduced by absorbing the brake fluid in the reservoir 40. As shown, it is not necessary to repeatedly perform the ON-OFF operation for the rear wheel side pressure reducing valves 21, 22 (see FIG. 1) (the portion surrounded by the ellipse in FIG. 3 (a)). Therefore, it is possible to prevent the vibration of the hydraulic pressure in the rear-wheel hydraulic pipe from being generated, and also to prevent the durability of the solenoid from being deteriorated and the generation of noise due to the vibration.

FIG. 4 schematically shows the configuration of a second embodiment of the brake device according to the present invention, in which an electric vehicle or an electric vehicle in which the rear wheels are driven by using an electric motor operated by electric power from a battery , The case where it is applied to a so-called hybrid vehicle is considered.

The illustrated braking device also has a brake pedal 51, a master cylinder 52, and
Brake fluid reservoir 53, wheel cylinders 54FR, 54FL,
54RR, 54RL, front wheel side hydraulic piping 55, rear wheel side hydraulic piping 56.

Front wheel hydraulic piping 55 and rear wheel hydraulic piping 56
Pump 57, 58, gate valve 59, 60, suction valve, respectively
61, 62, pressure increasing valves 63 to 66, pressure reducing valves 67 to 70, and check valves (check valves) 71 to 76 and 77 to 82 are provided, respectively.
The pumps 57 and 58 are driven by one motor, but are omitted in the figure. The purpose and operation of each of these constituent elements are the same as in the first embodiment shown in FIG. 1, and therefore detailed description thereof is omitted.

In the illustrated braking device, a reservoir 83 (corresponding to the reservoir 40 in FIG. 1) is further provided in the rear wheel side hydraulic pipe 56.
Is provided, and pressure sensors 85, 86 and 87, 88 are provided before and after the control valves of the front-wheel-side hydraulic pipe 55 and the rear-wheel-side hydraulic pipe 56, respectively. In addition, these pressure sensors are for detecting the pressure in each hydraulic pipe as input information in order to perform the regenerative coordinated control described later.

In the illustrated brake device, in addition to the configuration of FIG. 1, the master cylinder 52 and the control valve 60 are connected to the rear wheel hydraulic pipe 56.
A stroke simulator 84 is provided between and.
As will be described later, in an electric vehicle and a hybrid vehicle, this is because the braking force applied to the rear wheels during braking is the braking force generated by the hydraulic brake device and the regenerative braking using the motor for driving the rear wheels. It depends on the braking force from and obtained from.

That is, in a situation where the braking force corresponding to the driver's brake operation can be achieved by regenerative driving, it is preferable to perform only regenerative braking because the battery of the electric vehicle or hybrid vehicle can be charged. In this case, the gate valve 60 needs to be in the closed position so that the master cylinder pressure generated in response to the driver's brake operation does not act on the wheel cylinders 5RL, 5RR.
However, when the gate valve 60 is in the closed position in this manner, the downstream side of the master cylinder 3 in the rear wheel hydraulic pipe 56 is shut off, and the brake pedal 51 does not stroke in response to the driver's braking operation. This may occur and give the driver a feeling of strangeness. Therefore, by providing the stroke simulator 84, even if the gate valve 60 is in the closed position, the brake pedal 51 strokes in response to the driver's operation, so that the driver does not feel uncomfortable. To do.

In an electric vehicle and a hybrid vehicle, the electric power is not applied to the motor for driving the wheel during braking, but a rotational force is applied to the motor by the rotation of the wheel, whereby the motor is regenerated by operating as a generator. It is conceivable to perform the braking together with the braking operation of the brake device that is operated by the driver's braking operation.

However, in this case, if the braking force of the hydraulic brake device is generated in accordance with the braking operation by the driver as it is, the braking force generated by the regenerative braking is larger than the driver's intention. Power may be generated.

Therefore, in order to match the braking force of the vehicle as a whole, which is a combination of these two braking forces, with the driver's intention, cooperative control of the braking operation by the hydraulic braking device and the regenerative braking operation (regenerative cooperation). Control). Therefore, in the illustrated apparatus, an electronic control unit (ECU) 8 is a regenerative cooperative control means for performing cooperative control.
9, the brake device is controlled.

The electronic control unit 89 shown in the figure has a brake switch (B) for detecting that the brake pedal 51 has been operated by the driver, as information related to the present brake device.
BLS signal from LS) 90, stroke signal from stroke sensor 90 that detects the amount of movement of the brake pedal, and front wheel side hydraulic piping 5 from pressure sensors 85 and 87.
5, the hydraulic signal in each of the rear-wheel hydraulic pipes 56 and the control pressure signal from the pressure sensors 86 and 88 are input. In addition, the wheel speed of each wheel and / or the acceleration of the vehicle is also input to the electronic control unit 89 from a wheel speed sensor and / or an acceleration sensor (G sensor) 92.

Based on these input information, the electronic control unit 89 performs data communication with the regenerative control ECU 93 for performing the regenerative control by the motor for driving the wheels, while coordinating operation between both ECUs. , Outputs a control operation command to the brake device. That is, as described above, in order that the braking force of the vehicle as a whole matches the driver's intention, that is, the braking operation by the driver, the target fluid in the rear wheel side hydraulic pipe 56 is considered in consideration of the braking force by the regenerative control. In addition to setting the pressure, the solenoid that drives each control valve and the motor that drives the hydraulic pump are appropriately controlled in order to obtain the braking force corresponding to this target hydraulic pressure.

That is, during the coordinated control of the regenerative braking and the braking by the hydraulic pressure, the solenoid of the gate valve 60 is turned on to bring the gate valve 60 into the closed position, and like the first embodiment described above, Hydraulic pressure from pump 58 is applied to wheel cylinder 54
Pressure increasing mode introduced to RR, 54RL, holding mode for closing pressure increasing valves 65, 66 to maintain the pressure of wheel cylinders 54RR, 54RL, pressure increasing valves 65, 66 closed, pressure reducing valves 69, 70 open and wheel Control is performed so as to obtain the target pressure by appropriately executing the pressure reducing mode in which the pressures of the cylinders 54RR and 54RL are reduced. At this time, the master cylinder pressure generated in response to the driver's brake operation is the stroke simulator 84
Therefore, the brake pedal 51 makes a stroke according to the operation of the driver. Note that the non-execution of the regenerative braking, the anti-skid control, and the traction control are the same as those in the above-described first embodiment.

Similar to FIG. 2, FIG. 5 is a characteristic diagram schematically showing the relationship between the hydraulic pressure and the liquid amount in each of the front wheel side hydraulic piping and the rear wheel side hydraulic piping. Here, the solid line is the characteristic curve in the brake device according to the present invention, and the broken line is the characteristic curve in the conventional brake device.

As is apparent from the figure, also in this case, the hydraulic pressure-fluid amount characteristic on the rear wheel side (rear wheel hydraulic pipe) can be made substantially equal to that on the front wheel side (front wheel hydraulic pipe).

FIG. 6 is a time chart showing the operation of the solenoid for driving the pump motor and the valve provided in the hydraulic pipe in the braking operation for each of the braking apparatus shown in FIG. 4 and the conventional braking apparatus. Here, FIG. 6 (a) shows a conventional braking device, and FIG. 6 (b) shows a braking device according to the present invention. The figure also shows changes in vehicle deceleration due to hydraulic pressure during braking.

As is clear from FIG. 6 (b), in this case as well,
In the brake device of FIG. 4, the brake fluid pressure supplied to the wheel cylinders 54RL, 54RR on the side of the rear wheel side hydraulic pipe 56 is larger than the originally required value, so that the reservoir 83 absorbs the brake fluid. Since it is intended to lower the solenoid valve, it is not necessary to repeatedly perform the ON / OFF operation of the solenoid of the shutoff valve unlike the portion surrounded by the ellipse in FIG. 6 (a). Therefore, it is possible to avoid vibration in the hydraulic pressure in the rear-wheel hydraulic pipe, and also to prevent the durability of the solenoid from being deteriorated and the generation of noise due to vibration.

In addition, in the present embodiment, since it is possible to suppress the consumption of battery power by driving the pressure reducing valve, it is possible to increase the mileage per charge in an electric vehicle. In addition, in a hybrid vehicle, it is possible to contribute to an increase in battery life, and it is possible to improve energy efficiency of the vehicle.

Further, in the present embodiment, since the hydraulic pressure fluctuation of the rear wheel side hydraulic system is suppressed, the braking force corresponding to the braking operation of the driver can be realized without giving the driver a feeling of discomfort. In addition, since the chances of performing the regenerative braking force adjustment control corresponding to the fluid pressure fluctuation are reduced, the stability of the regenerative cooperative control can be improved.

In the configuration of the embodiment of the present invention, the vehicle speed of the own vehicle is changed according to the inter-vehicle distance from the preceding vehicle traveling in front of the own vehicle as disclosed in Japanese Patent Laid-Open No. 2000-168395. It is also possible to apply to a so-called preceding vehicle tracking control device for controlling. In this case, it can be achieved by creating the above-described pressure increasing mode when decelerating the own vehicle to increase the inter-vehicle distance and creating the above pressure reducing mode when stopping the deceleration.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a configuration of a first embodiment of a brake device according to the present invention.

FIG. 2 is a characteristic diagram schematically showing the relationship between hydraulic pressure and liquid amount in the hydraulic piping of the brake device in FIG.

FIG. 3 is a time chart showing a braking operation in the brake device of FIG. 1 and a conventional brake device.

FIG. 4 is a diagram schematically showing a configuration of a second embodiment of a brake device according to the present invention.

5 is a characteristic diagram schematically showing the relationship between hydraulic pressure and liquid amount in the hydraulic pipe of the brake device in FIG.

FIG. 6 is a time chart showing a braking operation in the brake device of FIG. 4 and a conventional brake device.

[Explanation of symbols]

1,51 brake pedal 2 Hydraulic pressure booster 3,52 master cylinder 4,53 Brake fluid reservoir 5,54 wheel cylinder 6,55 Front-wheel hydraulic piping 7,56 Rear wheel side hydraulic piping 8,85,86,87,88 Pressure sensor 9, 10, 57, 58 pumps 11, 12, 59, 60 Gate valve 13, 14, 61, 62 suction valve 15, 16, 17, 18, 63, 64, 65, 66 Booster valve 19, 20, 21, 22, 67, 68, 69, 70 Pressure reducing valve 23, 24 damper 25-36, 71-82 Check valve 37,137 motor 38 Controller 39,92 Vehicle speed sensor 40 reservoir 84 stroke simulator 89 Electronic control unit 90 brake switch 91 Stroke sensor 93 Regenerative control unit

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Claims (4)

[Claims] 1. A master cylinder, a hydraulic fluid reservoir,
Front wheel side hydraulic pressure source, rear wheel side hydraulic pressure source, front wheel side braking means,
Rear wheel side braking means, a front wheel side hydraulic system for supplying hydraulic pressure from the front wheel side hydraulic pressure source to the front wheel side braking means, and hydraulic pressure from the rear wheel side hydraulic pressure source for the rear wheel side braking means. And a control valve provided on the front wheel side hydraulic system and the rear wheel side hydraulic system for adjusting the hydraulic pressure of each hydraulic system, and the front wheel side hydraulic pressure source. In a vehicle brake device comprising a common drive source for driving the rear wheel side hydraulic pressure source and a braking mechanism for applying a braking force to each of the front wheels and the rear wheels, the rear wheel side hydraulic system absorbs a fluid amount. A braking device characterized in that means are provided. 2. The brake system according to claim 1, wherein the rear wheel hydraulic system is located immediately downstream of the discharge side of the rear wheel hydraulic pressure source, and the rear wheel hydraulic pressure source and the master cylinder. And a check valve for suppressing the flow from the master cylinder side to the rear wheel side hydraulic pressure source side, and the liquid amount absorbing means is connected to a discharge port of the rear wheel side hydraulic pressure source. A brake device for a vehicle, wherein the brake device is arranged between the check valve and the check valve. 3. The brake device according to claim 1, wherein the brake device is applied to a vehicle further including an electric motor that drives at least one of front wheels and rear wheels. 4. The brake device according to claim 3, further comprising an electric motor that drives rear wheels, and is applied to a vehicle that brakes the rear wheels by a regenerative operation of the electric motor. .