JP7256006B2 - VEHICLE BRAKE DEVICE AND METHOD OF CONTROLLING VEHICLE BRAKE DEVICE - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vehicle brake system and a control method for the vehicle brake system.

2. Description of the Related Art Conventionally, a vehicle brake device includes a hydraulic brake that generates a hydraulic braking force using hydraulic pressure generated in response to a driver's braking operation, and a regenerative brake that generates a regenerative braking force. 2. Description of the Related Art A vehicle brake system capable of executing control for distributing a braking force to a braking force and a regenerative braking force (hereinafter also referred to as “regenerative cooperation”) is known.

The purpose of a regenerative brake used in a vehicle brake system is to convert the kinetic energy of the wheels during braking into electrical energy, thereby effectively utilizing the energy. The maximum regenerative braking force that can be regenerated by the regenerative braking is limited by the vehicle speed during braking of the vehicle, the state of charge of the battery, and the like. Therefore, even while the hydraulic brake is being operated, the ratio of the braking force by the hydraulic brake and the braking force by the regenerative brake can be changed according to the maximum regenerative braking force to increase the ratio of the regenerative brake. It is also preferable from the viewpoint of effective use of energy.

Various methods have been proposed to perform regenerative cooperation. For example, in Patent Document 1, there is provided between a hydraulic brake for the front wheels and a hydraulic brake for the rear wheels, and the flow rate of the brake fluid from the hydraulic brake side of the front wheels to the hydraulic brake side of the rear wheels is continuously controlled. and a pressure reducing valve capable of decompressing the brake fluid supplied to the rear wheel hydraulic brake, and when reducing the hydraulic pressure braking force of the front wheel hydraulic brake, A vehicle brake system is disclosed in which the opening degree of an adjustment valve is continuously increased and the pressure reduction valve on the rear wheel side is opened.

WO2012/086290

However, when the vehicle braking device disclosed in Patent Document 1 is applied to a front-wheel-drive hybrid vehicle and an electric vehicle in which the front wheels of the vehicle are driven by the driving force output from the internal combustion engine or the driving motor, the regenerative cooperation is not performed. During this time, it is controlled so that no braking force is applied to the rear wheels. Specifically, in the vehicle brake device disclosed in Patent Document 1, in order to generate the hydraulic braking force together with the regenerative braking force acting on the front wheels, a regulating valve that supplies brake fluid to the hydraulic brakes of the front wheels; By keeping the pressure reducing valve that reduces the hydraulic braking force of the rear wheels in an open state and controlling the opening of the adjusting valve on the rear wheel side, the hydraulic braking force of the front wheels is reduced as much as possible. The hydraulic braking force is adjusted so that the sum of the hydraulic braking force and the regenerative braking force matches the braking force requested by the driver.

Therefore, the ratio of the braking force distributed to the front wheels becomes excessive, and the vehicle may exhibit unstable behavior such as understeer. When the vehicle understeers, in order to stabilize the behavior of the vehicle, it is necessary to reduce the regenerative braking force of the front wheels while increasing the hydraulic pressure braking force of the rear wheels, which may reduce the energy utilization efficiency. There is

On the other hand, while regenerative cooperation is being performed, by generating hydraulic braking force on the rear wheels together with the regenerative braking force acting on the front wheels, the balance between the braking forces on the front wheels and the rear wheels is improved, and the vehicle becomes more stable. It is considered that the stability of behavior is improved and the decrease in energy utilization efficiency can be suppressed. However, when adjusting the hydraulic pressure braking force by generating the hydraulic pressure braking force on the rear wheels, there is a risk that the brake fluid will flow in both directions via the pressure reducing valve of the hydraulic pressure brakes on the front wheels. In this case, it is necessary to provide two filters in order to collect foreign matter mixed in the brake fluid flowing bidirectionally through the pressure reducing valve on the front wheel side. While only the regenerative braking force is being generated, the brake fluid that flows from the master cylinder into the hydraulic circuit flows into and out of the low-pressure accumulator via the rear-wheel pressure reducing valve. two filters are provided. Therefore, in the case of a four-wheeled vehicle, for example, eight filters must be provided for four pressure reducing valves.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a vehicle brake device capable of reducing the total number of filters provided for collecting foreign matter in the brake fluid passing through the pressure reducing valve, and a control method thereof. .

According to one aspect of the present invention, a first hydraulic brake for generating hydraulic braking force on the front wheels, a second hydraulic brake for generating hydraulic braking force on the rear wheels, and converting the kinetic energy of the front wheels. and a regenerative brake for generating a regenerative braking force, wherein the braking force can be distributed between the hydraulic braking force and the regenerative braking force, wherein the brake fluid is supplied to the first hydraulic brake. a first regulating valve that continuously adjusts the flow rate of the second hydraulic brake, a second regulating valve that continuously adjusts the flow rate of the brake fluid supplied to the second hydraulic brake, and the hydraulic pressure of the first hydraulic brake a first pressure reducing valve for reducing the braking force; a second pressure reducing valve for reducing the hydraulic pressure braking force of the second hydraulic brake; An accumulator to be supplied, and a control device for controlling the first regulating valve, the first pressure reducing valve, the second regulating valve and the second pressure reducing valve, wherein the control device generates only regenerative braking force During this period, the first regulating valve and the first pressure reducing valve are closed, while the second regulating valve and the second pressure reducing valve are open, and the second regulating valve and the second pressure reducing valve are opened. While the brake fluid is supplied to the accumulator via and the hydraulic pressure braking force is generated together with the regenerative braking force, the second pressure reducing valve is closed while the first pressure reducing valve and the second adjusting valve are closed. In the valve open state, brake fluid is supplied to the second hydraulic brake, and the flow rate of the brake fluid supplied to the accumulator is adjusted by the first adjusting valve through the first adjusting valve and the first pressure reducing valve. By doing so, the hydraulic braking force of the rear wheels is adjusted, and a vehicle braking device is provided in which the first pressure reducing valve is opened in a state where the pressure on the side of the first hydraulic brake is higher than the pressure on the side of the accumulator. .

According to another aspect of the present invention, a first hydraulic brake for generating a hydraulic braking force on the front wheels, a second hydraulic brake for generating a hydraulic braking force on the rear wheels, and a motion of the front wheels. A regenerative brake that converts energy to generate a regenerative braking force, a first control valve that continuously adjusts the flow rate of brake fluid supplied to the first hydraulic brake, and a second hydraulic brake that supplies the brake fluid. A second adjusting valve for continuously adjusting the flow rate of the brake fluid, a first pressure reducing valve for reducing the hydraulic braking force of the first hydraulic brake, and a hydraulic braking force of the second hydraulic brake. a second pressure reducing valve that reduces pressure; an accumulator to which brake fluid is supplied when pressure is reduced by the first pressure reducing valve or the second pressure reducing valve; and a control device for controlling a second pressure reducing valve, and a control method for a vehicle brake device capable of distributing braking force to hydraulic braking force and regenerative braking force, wherein the control device controls only regenerative braking force. is generated, the first regulating valve and the first pressure reducing valve are closed, while the second regulating valve and the second pressure reducing valve are open, and the second regulating valve and the second pressure reducing valve are closed. While the brake fluid is supplied to the accumulator through the pressure reducing valve and the hydraulic pressure braking force is generated together with the regenerative braking force, the second pressure reducing valve is closed while the first pressure reducing valve and the second pressure reducing valve are closed. While supplying brake fluid to the second hydraulic brake with the adjusting valve in the open state, the first adjusting valve reduces the amount of brake fluid supplied to the accumulator via the first adjusting valve and the first pressure reducing valve. A vehicular brake device that adjusts the hydraulic braking force of the rear wheels by adjusting the flow rate and opens the first pressure reducing valve in a state where the pressure on the first hydraulic brake side is higher than the pressure on the accumulator side. A control method is provided.

As described above, according to the present invention, it is possible to reduce the total number of filters provided for collecting foreign matter in the brake fluid passing through the pressure reducing valve.

It is a mimetic diagram showing an example of composition of brake equipment for vehicles concerning an embodiment of the invention. FIG. 4 is an explanatory diagram of a hydraulic circuit that constitutes a hydraulic brake in the vehicle brake system according to the same embodiment; FIG. 5 is an explanatory diagram showing the state of the hydraulic circuit while braking force is generated only by regenerative braking force; FIG. 5 is an explanatory diagram showing the state of the hydraulic circuit while the braking force is distributed to the hydraulic braking force and the regenerative braking force; FIG. 5 is an explanatory diagram showing the state of the hydraulic circuit when generating hydraulic braking force from a state in which only regenerative braking force is generated; FIG. 5 is an explanatory diagram showing the state of the hydraulic circuit when the brake pedal is suddenly released; It is a flowchart which shows the process by brake ECU of the brake equipment for vehicles which concerns on the same embodiment. 4 is a timing chart showing an example of the operation of the vehicle brake system; 4 is a flow chart showing processing for generating hydraulic braking force from a state in which only regenerative braking force is generated; FIG. 4 is a timing chart showing an operation when generating hydraulic braking force from a state in which only regenerative braking force is generated; FIG. It is a timing chart which shows a reference example. 4 is a flowchart of processing that is performed when the brake pedal is suddenly released while the braking force is distributed between the regenerative braking force and the hydraulic braking force.

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and drawings, constituent elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

<1. Overall Configuration of Vehicle Brake Device>
First, the overall configuration of the vehicle brake system according to this embodiment will be described. FIG. 1 is a schematic diagram showing a configuration example of a vehicle brake device 100. As shown in FIG. In FIG. 1, only one front wheel F and one rear wheel R are shown for easy understanding.

A vehicle brake device 100 according to this embodiment includes a hydraulic brake and a regenerative brake that utilizes the kinetic energy of the front wheels. In the vehicle brake device 100, the braking force is distributed between the hydraulic braking force and the regenerative braking force with respect to the braking force requested by the driver.

The vehicle brake device 100 is equipped with a drive motor 125 as a regenerative brake that functions as a drive source for driving the front wheels during running and as a generator during braking to generate regenerative braking force on the front wheels F. Driving of the drive motor 125 is controlled by the motor ECU 110 . Specifically, the motor ECU 110 controls the operation of the inverter 123 to supply the electric power of the battery 121 to the drive motor 125 or charge the battery 121 with the electric power regenerated by the drive motor 125 .

Further, the vehicle brake device 100 is equipped with hydraulic brakes 38a and 38b that generate hydraulic braking force corresponding to the supplied hydraulic pressure to the front wheels F and the rear wheels R, respectively. The hydraulic pressure of the brake fluid supplied to each of the hydraulic brake (first hydraulic brake) 38a for the front wheels F and the hydraulic brake (second hydraulic brake) 38b for the rear wheels R is controlled by the brake ECU 90. be. Specifically, the brake ECU 90 adjusts the hydraulic pressure supplied to the front wheel F hydraulic brake 38 a and the rear wheel R hydraulic brake 38 b by controlling the operation of the hydraulic pressure unit 20 .

That is, the vehicle brake device 100 according to the present embodiment can generate regenerative braking force and hydraulic braking force on the front wheels F, and can generate hydraulic braking force on the rear wheels R. .

The brake ECU 90 and the motor ECU 110 are communicably connected via a network such as a CAN (Controller Area Network). The brake ECU 90 controls the regenerative braking force generated at the front wheels F by giving a regenerative braking command value to the motor ECU 110 . The motor ECU 110 transmits to the brake ECU 90 information about the maximum regenerative braking force that can be output at that time.

The brake ECU 90 or the motor ECU 110 may be configured partially or wholly, for example, by a microcomputer or a microprocessor unit, or may be configured by an updatable device such as firmware. Also, part or all of the brake ECU 90 or the motor ECU 110 may be a program module or the like executed by a command from a CPU or the like.

In addition to the stroke signal supplied from the electric booster 13 and the sensor signal of the master cylinder hydraulic pressure sensor 24 for detecting the hydraulic pressure (master cylinder pressure) in the master cylinder 14, the brake ECU 90 receives the respective wheel RF , LR, LF, and RR from wheel speed sensors (not shown), etc. (see FIG. 2).

<2. Hydraulic circuit>
Next, an example of the hydraulic circuit 1 that constitutes the hydraulic brake in the vehicle brake system according to the present embodiment will be briefly described with reference to FIG.

A hydraulic circuit 1 shown in FIG. 2 is a hydraulic circuit of a brake system for a four-wheeled vehicle. The hydraulic circuit 1 is applied to a hydraulic circuit of a so-called X-shaped piping system in which two brake systems are provided, and each system brakes one front wheel and a rear wheel diagonally opposite to the front wheel as one set. be. The brake hydraulic circuit 1 can be widely applied to vehicles including two-wheeled vehicles as well as four-wheeled vehicles.

In the hydraulic circuit 1, the pedaling force applied to the brake pedal 11 is amplified by the booster 13 and transmitted to the master cylinder 14 as a hydraulic pressure generation source. Two pressure chambers defined by a primary piston and a secondary piston are formed in the master cylinder 14 . When the driver depresses the brake pedal, each piston is pressed, and the brake fluid moves into the hydraulic circuit 1 through the hydraulic ports communicating with the pressurizing chambers.

The booster 13 is connected to the brake pedal 11 side via an input rod 15, and the amplified pedaling force is transmitted to the master cylinder 14 via a push rod connected to the primary piston. In this embodiment, an electric booster is used as the booster 13 . The electric booster is a device capable of adjusting the amplification force when transmitting the force applied by the driver to the brake pedal 11 to the piston of the master cylinder 14 . Further, the force applied to the brake pedal 11 by the driver and the amplified force of the booster 13 press the output rod of the booster 13 toward the master cylinder 14, whereas the return spring provided in the booster 13 The return force and the reaction force of the master cylinder 14 push the output rod in the opposite direction. That is, the amplified force assists the driver's depression of the brake pedal 11, and the restoring force of the return spring ensures that the booster 13 and the brake pedal 11 return to their initial positions after the driver's braking operation. In addition, the reaction force of the master cylinder 14 acts against the driver's depression of the brake pedal 11 .

From the hydraulic ports communicating with the two pressure chambers of the master cylinder 14, the first hydraulic circuit 28 and the second hydraulic circuit 28 are directed to the hydraulic brakes 38a to 38d of the respective wheels RF, LR, LF, RR. A pressure circuit 30 extends. The hydraulic circuit 1 of the vehicle brake system according to the present embodiment has an X-shaped piping system, and the wheel cylinder of the hydraulic brake 38a of the right front wheel RF and the wheel cylinder of the hydraulic brake 38b of the left rear wheel LR have a second Brake fluid is supplied via one hydraulic circuit 28 . Brake fluid is supplied through the second hydraulic circuit 30 to the wheel cylinder of the hydraulic brake 38c for the left front wheel LF and the wheel cylinder of the hydraulic brake 38d for the right rear wheel RR. As a result, each of the hydraulic brakes 38a-38d can apply a braking force to each of the wheels RF, LR, LF, and RR by hydraulic pressure.

The hydraulic circuit 1 includes a first hydraulic circuit 28 and a second hydraulic circuit 30 having the same configuration. Brake fluid is supplied from the master cylinder 14 to the first hydraulic circuit 28 and the second hydraulic circuit 30 . The first hydraulic circuit 28 will be briefly described below, and the description of the second hydraulic circuit 30 will be omitted.

The first hydraulic circuit 28 includes, as solenoid valves, a normally open circuit control valve 36a capable of linear control, a normally closed suction valve 34a which is ON/OFF controlled, and a normally open type pressure booster valve capable of linear control. (Adjusting valves) 58aa and 58ba, and pressure reducing valves 54aa and 54ba that are normally closed and on/off controlled. The first hydraulic circuit 28 also includes a pump 44a driven by a pump motor 96, a low pressure accumulator 71a, and a damper 73a. Note that the number of pumps 44a is not limited to one.

A first pressure increasing valve 58aa and a first pressure reducing valve 54aa provided adjacent to the hydraulic brake 38a of the right front wheel RF are used for ABS (Antilock Brake System) control or ESC (Electronic Stability Control) control of the right front wheel RF. Used. A second pressure increasing valve 58ba and a second pressure reducing valve 54ba provided adjacent to the hydraulic brake 38b of the left rear wheel LR are used for ABS control or ESP control of the left rear wheel LR.

The first pressure increase valve 58aa for the right front wheel RF is provided between the circuit control valve 36a and the hydraulic brake 38a for the right front wheel RF. The linearly controllable first pressure increasing valve 58aa continuously adjusts the flow rate of brake fluid from the circuit control valve 36a side to the wheel cylinder side of the hydraulic brake 38a of the right front wheel RF. The first pressure-increasing valve 58aa has a check valve that, when the first pressure-increasing valve 58aa is closed, allows the brake fluid to flow from the hydraulic brake 38a side to the circuit control valve 36a side and restricts the flow in the opposite direction. A bypass flow path is provided.

The first pressure reducing valve 54aa for the right front wheel RF is a solenoid valve that can be switched only to a fully open or fully closed state, and is provided between the wheel cylinder of the hydraulic brake 38a for the right front wheel RF and the low pressure accumulator 71a. It is The first pressure reducing valve 54aa reduces the pressure of the brake fluid supplied to the wheel cylinder of the hydraulic brake 38a of the right front wheel RF in the open state. By intermittently opening and closing the first pressure reducing valve 54aa, it is possible to adjust the flow rate of the brake fluid flowing from the wheel cylinder of the hydraulic brake 38a of the right front wheel RF to the low pressure accumulator 71a.

The second pressure increase valve 58ba for the left rear wheel LR is provided between the circuit control valve 36a and the hydraulic brake 38b for the left rear wheel LR. The linearly controllable second pressure increasing valve 58ba continuously adjusts the flow rate of the brake fluid from the circuit control valve 36a side to the wheel cylinder side of the hydraulic brake 38b of the left rear wheel LR. The second pressure-increasing valve 58ba is provided with a check valve that, when the second pressure-increasing valve 58ba is closed, allows the brake fluid to flow from the hydraulic brake 38b side to the circuit control valve 36a side, while restricting the flow in the opposite direction. A bypass flow path is provided.

The second pressure reducing valve 54ba for the left rear wheel LR is a solenoid valve that can be switched only to a fully open or fully closed state. is provided in The second pressure reducing valve 54ba reduces the pressure of the brake fluid supplied to the wheel cylinder of the hydraulic brake 38b of the left rear wheel LR in the open state. By intermittently opening and closing the second pressure reducing valve 54ba, the flow rate of the brake fluid flowing from the wheel cylinder of the hydraulic brake 38b of the left rear wheel LR to the low pressure accumulator 71a can be adjusted.

The circuit control valve 36a is provided so as to connect or disconnect between the pressure increase valves 58aa, 58ba and the master cylinder 14. As shown in FIG. The suction valve 34a is provided to communicate or block communication between the master cylinder 14 and the suction side of the pump 44a. A master cylinder hydraulic pressure sensor 24 is provided in a conduit between the circuit control valve 36a and the intake valve 34a and the master cylinder 14 . Since these are the same as those for conventional ESC control, detailed description thereof will be omitted.

The second hydraulic circuit 30 controls a hydraulic brake 38c for the left front wheel LF and a hydraulic brake 38d for the right rear wheel RR. In the second hydraulic circuit 30, the wheel cylinder of the hydraulic brake 38a for the right front wheel RF in the description of the first hydraulic circuit 28 is replaced with the wheel cylinder of the hydraulic brake 38c for the left front wheel LF. It is configured in the same manner as the first hydraulic circuit 28 except that the wheel cylinder of the hydraulic brake 38b is replaced with the wheel cylinder of the hydraulic brake 38d for the right rear wheel RR.

<3. Operation>
Next, an operation example of the vehicle brake device 100 according to the present embodiment during regeneration cooperation will be described. In the following description, the operation of the vehicle brake device 100 will be described while only showing the first hydraulic circuit 28, but the second hydraulic circuit 30 operates in the same manner.

FIG. 3 shows the state of the first hydraulic circuit 28 while the braking force is generated solely by the regenerative braking force, and FIG. , the state of the first hydraulic circuit 28 is shown.

As shown in FIG. 3, while the braking force is generated only by the regenerative braking force, the circuit control valve 36a, the second pressure increasing valve 58ba, and the second pressure reducing valve 54ba are kept open, and the intake valve 34a, The first pressure increasing valve 58aa and the second pressure reducing valve 54aa are kept closed. The brake fluid supplied from the master cylinder 14 to the first hydraulic circuit 28 is not supplied to the hydraulic brake 38a side of the right front wheel RF, but is supplied to the hydraulic brake 38b side of the left rear wheel LR.

However, since the second pressure reducing valve 54ba is kept open, the brake fluid supplied to the hydraulic brake 38b side of the left rear wheel LR is supplied to the low pressure accumulator 71a via the second pressure reducing valve 54ba. supplied. Therefore, no hydraulic braking force is generated in the hydraulic brake 38b of the left rear wheel LR, and the braking force is exerted only by the regenerative braking force generated in the right front wheel RF. At this time, the first pressure increasing valve 58aa and the first pressure reducing valve 54aa are closed so that the residual pressure due to the spring force of the low pressure accumulator 71a produces a drag torque and the hydraulic braking force does not act on the right front wheel RF. It is

In the state shown in FIG. 3, the amount of brake fluid supplied from the master cylinder 14 to the first hydraulic circuit 28 increases or decreases according to the stroke signal supplied from the electric booster 13. The brake fluid supplied to the hydraulic brake 38b side of the LR can bi-directionally flow through the second pressure reducing valve 54ba. For this reason, the second pressure reducing valve 54ba includes a filter for collecting foreign matter flowing from the hydraulic brake 38b side of the left rear wheel LR to the low pressure accumulator 71a side, A filter is provided to collect foreign matter flowing toward the pressure brake 38b.

Further, as shown in FIG. 4, while the braking force is distributed to the regenerative braking force and the hydraulic braking force, the circuit control valve 36a, the first pressure reducing valve 54aa and the second pressure increasing valve 58ba are open. The suction valve 34a and the second pressure reducing valve 54ba are maintained in the closed state. By adjusting the opening degree of the first pressure increasing valve 58aa, the flow rate of the brake fluid supplied to the hydraulic brake 38a side of the right front wheel RF is adjusted, and the brake fluid is supplied to the hydraulic brake 38b of the left rear wheel LR. adjust the fluid pressure.

At this time, since the first pressure reducing valve 54aa is kept open, the brake fluid supplied to the hydraulic brake 38a side of the right front wheel RF is supplied to the low pressure accumulator 71a via the first pressure reducing valve 54aa. supplied. Therefore, a relatively small hydraulic braking force is generated in the hydraulic brake 38a for the right front wheel RF in accordance with the spring force of the low pressure accumulator 71a. Therefore, braking force is applied to the front and rear wheels in a well-balanced manner by the regenerative braking force and the hydraulic braking force generated at the right front wheel RF and the hydraulic braking force generated at the left rear wheel LR. The maximum regenerative braking force that can be regenerated by regenerative braking is limited by the vehicle speed during braking and the state of charge of the battery. The degree of opening of the first pressure increasing valve 58aa is adjusted as the target value of the braking force.

Similarly, in the other second hydraulic circuit 30, braking force is applied to the front and rear wheels in a well-balanced manner by the regenerative braking force and hydraulic braking force generated at the left front wheel LF and the hydraulic pressure braking force generated at the right rear wheel RR. . As a result, the braking force is distributed to the front wheels and the rear wheels, and it is possible to suppress unstable vehicle behavior such as understeer due to an increase in the ratio of the braking force to the front wheels. Moreover, since it is no longer necessary to reduce the regenerative braking force in order to eliminate the unstable behavior of the vehicle, it is possible to suppress a decrease in energy utilization efficiency.

Here, the braking force requested by the driver cannot be covered by the regenerative braking force alone, and when the state shown in FIG. 3 changes to the state shown in FIG. The valve 54ba is closed and the first pressure reducing valve 54aa is opened to increase the hydraulic pressure of the hydraulic brake for the left rear wheel LR. At this time, when the pressure on the side of the low pressure accumulator 71a is higher than the pressure on the side of the hydraulic brake 38a of the right front wheel RF and the first pressure reducing valve 54aa is opened, the hydraulic pressure brake 38a of the right front wheel RF is released from the side of the low pressure accumulator 71a. Brake fluid moves to the side.

When the first pressure reducing valve 54aa is controlled in this manner, not only the second pressure reducing valve 54ba of the hydraulic brake 38b of the left rear wheel LR but also the first pressure reducing valve 54aa of the hydraulic brake 38a of the right front wheel RF Also, the brake fluid can flow in both directions from the hydraulic brakes 38a and 38b to the low pressure accumulator 71a and from the low pressure accumulator 71a to the hydraulic brakes 38a and 38b. Therefore, the first pressure reducing valve 54aa and the second pressure reducing valve 54ba are provided with a filter for preventing foreign matter from flowing from the side of the hydraulic brake 38a to the side of the low pressure accumulator 71a, and a hydraulic brake from the side of the low pressure accumulator 71a. A filter is required to prevent foreign matter from flowing into the 38a side.

On the other hand, in the vehicle brake device 100 according to the present embodiment, when the state shown in FIG. 3 is shifted to the state shown in FIG. After the pressure becomes higher than the pressure of , the first pressure reducing valve 54aa is opened. Therefore, brake fluid does not flow through the first pressure reducing valve 54aa from the low pressure accumulator 71a side to the hydraulic brake 38a side of the right front wheel RF. Therefore, a filter for preventing foreign matter from flowing from the first pressure reducing valve 54aa to the hydraulic brake 38a side from the low pressure accumulator 71a side can be omitted.

4, when the driver quickly releases the brake pedal 11, the master cylinder pressure becomes zero and the brake fluid in the first hydraulic circuit 28 flows into the master cylinder 14. As shown in FIG. Accordingly, as shown in FIG. 6, the brake fluid moves from the hydraulic brake 38a side of the right front wheel RF to the circuit control valve 36a side through the check valve provided in the first pressure increase valve 58aa. As a result, the pressure on the hydraulic brake 38a side of the right front wheel RF can be lower than the pressure on the low pressure accumulator 71a side.

At this time, if the first pressure reducing valve 54aa is kept open, brake fluid moves from the low pressure accumulator 71a side to the hydraulic brake 38a side of the right front wheel RF. In this case also, the first pressure reducing valve 54aa and the second pressure reducing valve 54ba are provided with a filter for preventing foreign matter from flowing from the hydraulic brake 38a side to the low pressure accumulator 71a side, and a filter from the low pressure accumulator 71a side. A filter is required to prevent foreign matter from flowing into the hydraulic brake 38a.

On the other hand, in the vehicle brake device 100 according to the present embodiment, when the driver quickly releases the brake pedal 11 in the state shown in FIG. The first pressure reducing valve 54aa is once closed until the pressure on the accumulator 71a side becomes higher than the pressure. After that, when the driver operates the brake pedal 11 and the required braking force cannot be covered only by the regenerative braking force, the pressure on the hydraulic brake 38a side of the right front wheel RF is higher than the pressure on the low pressure accumulator 71a side. After the state is reached, the first pressure increasing valve 58aa is closed and the first pressure reducing valve 54aa is opened.

Therefore, brake fluid does not flow from the low pressure accumulator 71a side to the hydraulic brake 38a side of the right front wheel RF via the first pressure reducing valve 54aa. Therefore, a filter for preventing foreign matter from flowing from the first pressure reducing valve 54aa to the hydraulic brake 38a side from the low pressure accumulator 71a side can be omitted.

<4. Processing example>
Next, the regeneration cooperation processing by the brake ECU 90 of the vehicle brake device 100 according to this embodiment will be described. FIG. 7 is a flowchart showing an example of basic processing by the brake ECU 90. As shown in FIG. In the vehicle brake device 100, the hydraulic braking force of the hydraulic brake 38b of the left rear wheel LR and the hydraulic pressure brake 38d of the right rear wheel RR is appropriately adjusted according to the fluctuation of the maximum regenerative braking force that can be regenerated by the regenerative brake. controlled. Only the hydraulic brake 38a for the right front wheel RF and the hydraulic brake 38b for the left rear wheel LR on the first hydraulic circuit 28 side will be described below. The brake 38c and the hydraulic brake 38d of the right rear wheel RR are similarly controlled.

First, the brake ECU 90 determines whether or not the driver requests a braking force (step S11). Specifically, the brake ECU 90 calculates the brake force requested by the driver based on the stroke signal supplied from the electric booster 13 . For example, the brake ECU 90 stores a map in which the correspondence relationship between the stroke amount and the required braking force is set in advance, and the brake ECU 90 calculates the required braking force based on the map and the stroke amount. If the calculated required braking force is a positive value, the brake ECU 90 determines that the driver has requested braking force.

If the driver does not request a braking force (S11/No), the brake ECU 90 terminates this routine and returns to step S11. On the other hand, if the driver requests braking force (S11/Yes), the brake ECU 90 determines whether or not the hydraulic braking force to be distributed to the requested braking force is necessary (step S13). For example, the brake ECU 90 calculates the hydraulic braking force command value as follows and determines whether the hydraulic braking force is necessary.

The brake ECU 90 stores a map in which the correspondence relationship between the stroke amount of the booster 13 and the braking force requested by the driver is set in advance. Calculate In addition, the brake ECU 90 acquires information on the maximum regenerative braking force, which is the maximum value of the regenerative braking force that can be output at this time, from the motor ECU 110, and regenerates the smaller value of the maximum regenerative braking force and the required braking force. It is output to the motor ECU 110 as a braking force command value.

After outputting the regenerative braking force command value to the motor ECU 110, the brake ECU 90 acquires from the motor ECU 110 information on the actual regenerative braking force corresponding to the current actual regenerative braking force. Then, the brake ECU 90 sets a value obtained by subtracting the regenerative brake force command value from the required brake force as the hydraulic brake force command value, and controls the hydraulic brake 38b of the left rear wheel LR so as to obtain the hydraulic brake force command value. Calculate the target value of the pressure in the wheel cylinder of When the calculated target value of the wheel cylinder pressure is a positive value, the brake ECU 90 determines that hydraulic braking force is required.

If the hydraulic braking force is required (S13/Yes), the brake ECU 90 controls the hydraulic braking force to be applied to the hydraulic brake 38b of the left rear wheel LR (step S15). Specifically, the brake ECU 90 stores a map in which the corresponding relationship between the wheel cylinder pressure and the caliper volume is set in advance, and the brake ECU 90 stores the map and the master cylinder pressure detected by the master cylinder pressure sensor 24. , and the target value of the wheel cylinder pressure, the current caliper volume (actual caliper volume) and the target value of the caliper volume (target caliper volume) are calculated.

When the difference obtained by subtracting the actual caliper volume from the target caliper volume is a positive value, the brake ECU 90 opens the circuit control valve 36a, the first pressure reducing valve 54aa, and the second pressure increasing valve 58ba. The valve 34a, the first pressure increasing valve 58aa and the second pressure reducing valve 54ba are closed, and the rotation speed of the pump motor 96 is controlled. The rotation speed of the pump motor 96 at this time is determined based on the value of the difference obtained by subtracting the actual caliper volume from the target caliper volume.

On the other hand, if the difference obtained by subtracting the actual caliper volume from the target caliper volume is a negative value, the brake ECU 90 keeps the circuit control valve 36a, the first pressure reducing valve 54aa, and the second pressure increasing valve 58ba open. On the other hand, the intake valve 34a and the second pressure reducing valve 54ba are kept closed. In this state, the brake ECU 90 gradually increases the degree of opening of the first pressure increase valve 58aa to stop the pump motor 96 . As a result, the first pressure reducing valve 54aa is maintained in an open state, and the second pressure reducing valve 54ba is maintained in a closed state. 58aa. In this way, when the regenerative braking force is increased in a state where the hydraulic pressure braking force is generated in the hydraulic pressure brake 38b of the left rear wheel LR, the brake fluid supplied to the hydraulic pressure brake 38b of the left rear wheel LR is reduced. Hydraulic pressure can be reduced.

When the difference obtained by subtracting the actual caliper volume from the target caliper volume is a positive value, that is, when the actual caliper volume and the target caliper volume match, the brake ECU 90 closes the first pressure increasing valve 58aa, The first pressure reducing valve 54aa is opened. As a result, the hydraulic braking force of the hydraulic brake 38b for the left rear wheel LR can be maintained.

On the other hand, if the hydraulic braking force is not required (S13/No), the brake ECU 90 does not generate the hydraulic braking force and controls only the regenerative braking force (step S17). Specifically, the brake ECU 90 keeps the circuit control valve 36a, the second pressure increasing valve 58ba, and the second pressure reducing valve 54ba open, while the intake valve 34a, the first pressure increasing valve 58aa, and the first pressure reducing valve The valve 54aa is kept closed. Also, the pump motor 96 is put into a non-operating state.

As a result, although the brake fluid flowing into the first hydraulic circuit 28 from the master cylinder 14 is supplied to the hydraulic brake 38b side of the left rear wheel LR, the brake fluid is passed through the second pressure reducing valve 54ba to a low pressure. It is supplied to the accumulator 71a. Therefore, although a hydraulic pressure corresponding to the reaction force of the low-pressure accumulator 71a is generated in the hydraulic brake 38b for the left rear wheel LR, the hydraulic braking force should not be generated by the hydraulic pressure, or should be set to an extremely small value. can be done. It should be noted that once the process of step S17 is executed via step S15, a very small hydraulic pressure is also generated in the hydraulic brake 38a of the right front wheel RF.

After controlling the hydraulic braking force and the regenerative braking force in step S15, or controlling only the regenerative braking force in step S17, the brake ECU 90 determines whether or not to terminate the regenerative cooperative control (step S19). For example, the brake ECU 90 ends the regenerative cooperative control when it is determined that the maximum regenerative braking force has become zero or has a value close to zero based on the information acquired from the motor ECU 110. I judge. However, the method of determining whether or not to end regeneration cooperation is not limited to this example.

If the brake ECU 90 does not determine to end the cooperative regeneration control (S19/No), the process returns to step S11 and continues. On the other hand, when the brake ECU 90 determines to end the regenerative cooperative control (S19/Yes), it decreases the regenerative braking force and increases the hydraulic braking force of the hydraulic brake 38a for the right front wheel RF (step S21). . At this time, not only the hydraulic pressure braking force of the hydraulic brake 38b of the left rear wheel LR is increased, but also the hydraulic pressure braking force of the hydraulic pressure brake 38a of the right front wheel RF is increased. Even after the end, the braking force is distributed to the four wheels, and the behavior of the vehicle can be stabilized.

Next, the brake ECU 90 determines whether or not the actual regenerative braking force has become zero based on the calculated regenerative braking force command value (step S23). If the actual regenerative braking force is not zero (S23/No), the brake ECU 90 returns to step S11 and continues the process. On the other hand, when the actual regenerative braking force becomes zero (S23/Yes), the brake ECU 90 terminates the regenerative cooperative control (step S25).

The vehicle braking device 100 according to the present embodiment applies the hydraulic braking force of the hydraulic brakes of the rear wheels instead of the front wheels on which the regenerative braking force is acting when generating the hydraulic braking force during the regenerative cooperative control. adjust. Therefore, it is possible to suppress unstable behavior of the vehicle such as understeer due to an increase in the ratio of the braking force on the front wheel side. In addition, since unstable behavior of the vehicle can be suppressed, the regenerative braking force is not reduced in order to stabilize the behavior of the vehicle, and a decrease in energy utilization efficiency can be suppressed.

FIG. 8 is a timing chart showing an example of the operation of the vehicle brake device 100. As shown in FIG. In FIG. 8, in the graph of braking force Tq and time Time, the regenerative braking force (corresponding to the regenerative braking command value) is indicated by a solid line as regenerative torque Tq_E, and the braking force requested by the driver is indicated by a broken line as requested torque Tq_D. It is On the other hand, in the graph of the hydraulic pressure P of the hydraulic brake and the time Time, the hydraulic pressure Pw_R on the rear wheel side is indicated by a solid line, and the hydraulic pressure Pw_F on the front wheel side is indicated by a broken line.

As shown in the first region D in FIG. 8, while the braking force Tq_D requested by the driver can be covered by the regenerative braking force Tq_E, the first pressure increasing valve (EV_f) 58aa and the first pressure reducing valve (AV_f) on the front wheel side 54aa is closed. Also, the rear-wheel-side second pressure increase valve (EV_r) 58ba and the second pressure reduction valve (AV_r) 54ba are opened. Specifically, in area D, the requested braking force Tq_D increases due to the depression of the pedal, and accordingly the requested regenerative braking force also increases. At this time, a very small hydraulic pressure corresponding to the reaction force of the low-pressure accumulator 71a is generated in the hydraulic brake 38b for the left rear wheel LR, resulting in no or very small hydraulic braking force. The second pressure reducing valve 54ba on the rear wheel side remains open until the required regenerative braking force becomes greater than the maximum regenerative braking force and the target value of the pressure in the wheel cylinder of the rear wheel hydraulic brake becomes a positive value. maintained in a valved state. As a result, brake fluid corresponding to the amount of pedal operation is discharged to the low-pressure accumulator 71a.

When the required regenerative braking force becomes larger than the maximum regenerative braking force and the required braking force Tq_D by the driver cannot be covered by the regenerative braking force Tq_E alone, the second pressure reducing valve 54ba on the rear wheel side is closed. A hydraulic braking force corresponding to the amount of pedal operation is generated (region B). At this time, when the required regenerative braking force again decreases to the maximum regenerative braking force, the first pressure reducing valve 54aa on the front wheel side is closed, and the second pressure reducing valve 54ba on the rear wheel side is opened. . As a result, brake fluid corresponding to the amount of pedal operation is discharged to the low-pressure accumulator 71a (area D).

When the maximum regenerative braking force begins to increase, the difference between the target caliper volume and the actual caliper volume becomes negative. , the first pressure reducing valve 54aa on the front wheel side is opened (area C). When the maximum regenerative braking force stops increasing, the front wheel side first pressure increase valve 58aa is kept closed and the front wheel side first pressure reduction valve 54aa is kept open (region B).

After that, when the maximum regenerative braking force starts to decrease, the front wheel side first pressure reducing valve 54aa is kept closed and the front wheel side first pressure increasing valve 58aa is adjusted while adjusting the valve opening degree. The hydraulic braking force of the hydraulic brake 38a is increased (area E). At this time, the second pressure reducing valve (AV_r) 54ba on the rear wheel side is maintained in the closed state, and the second pressure increasing valve (EV_r) 58ba on the rear wheel side is maintained in the open state. The same pressure is applied to the hydraulic brake 38a and the hydraulic brake 38b on the rear wheel side. Thereafter, the first pressure increase valve 58aa on the front wheel side is fully opened, and the hydraulic pressure is controlled only by the pump 44a. Note that when the state (region D) in which the hydraulic pressure braking forces of the front wheel side hydraulic brake 38a and the rear wheel side hydraulic brake 38b are both zero (region D) changes to region E, the front wheel side first The pressure increase valve 58aa is quickly fully opened, and the hydraulic pressure is controlled only by the pump 44a.

Then, when the hydraulic pressure of the hydraulic brake 38a on the front wheel side and the hydraulic pressure of the hydraulic brake 38b on the rear wheel side become the hydraulic pressure corresponding to the braking force Tq_D requested by the driver, the operation of the pump 44a is stopped. (Area A). During this time, the degree of opening of the first pressure increase valve 58aa for the front wheels is controlled based on the states of the volumes of the hydraulic brakes 38a and 38b for the front wheels and the hydraulic brakes 38a and 38b for the rear wheels. is adjusted.

So far, the basic operation of the processing by the brake ECU 90 of the vehicle brake device 100 according to the present embodiment has been described. Processing for suppressing the flow of brake fluid from the low-pressure accumulator 71a side to the hydraulic brake 38a side via the first pressure reducing valve 54aa of the hydraulic brake 38a for the right front wheel RF will be described below.

FIG. 9 shows a flowchart of the process performed when shifting to the process of step S15 after it is determined in step S13 of the flowchart shown in FIG. 7 that the hydraulic braking force is required. Also, FIG. 10 shows a timing chart when the process is executed. In FIGS. 9 and 10, the period in which the braking force requested by the driver can be covered only by the regenerative braking force is denoted as "OS1", and the braking force requested by the driver is divided into the regenerative braking force and the hydraulic braking force. The period is written as "OS2".

During the period in which the braking force requested by the driver can be covered only by the regenerative braking force (the period up to time ti1), the first pressure increasing valve (EV_f) 58aa and the first pressure reducing valve (AV_f) 54aa are maintained in the closed state. 2 pressure increasing valve (EV_r) 58ba and second pressure reducing valve (AV_r) 54ba are maintained in the open state. During this period, the pump 44a is stopped. When the braking force requested by the driver cannot be covered by the regenerative braking force alone (time ti1), the brake ECU 90 closes the second pressure reducing valve 54ba. As a result, the hydraulic pressure Pw_R of the hydraulic brake 38b for the left rear wheel LR begins to rise. Also, at time ti1, the brake ECU 90 opens the first pressure increase valve 58aa. As a result, the hydraulic pressure Pw_F of the hydraulic brake 38a for the right front wheel RF also begins to rise. At time ti1, the pump 44a is driven as necessary.

After time ti1, the brake ECU 90 determines whether or not the hydraulic pressure Pw_F of the hydraulic brake 38a of the right front wheel RF is equal to or higher than the pressure P_a of the low pressure accumulator 71a (step S31). The hydraulic pressure Pw_F of the hydraulic brake 38a of the right front wheel RF can be calculated, for example, based on the flow rate of brake fluid supplied to the hydraulic brake 38a of the right front wheel RF. Also, the pressure P_a on the side of the low-pressure accumulator 71a uses a value preset according to the spring constant of the spring of the low-pressure accumulator 71a.

The pressure P_a on the side of the low-pressure accumulator 71a may be an actual measurement value or a model value. It is possible to reduce the possibility that the first pressure reducing valve 54aa is opened while the hydraulic pressure Pw_F of the hydraulic brake 38a of the right front wheel RF is higher than the hydraulic pressure Pw_F.

During the period from time ti1 to time ti2, the hydraulic pressure Pw_F of the hydraulic brake 38a of the right front wheel RF is less than the pressure P_a on the side of the low-pressure accumulator 71a (S31/No), so the brake ECU 90 closes the first pressure reducing valve 54aa. The valve state is maintained (step S35). The brake ECU 90 repeats steps S31 to S35 until the hydraulic pressure Pw_F of the hydraulic brake 38a for the right front wheel RF becomes equal to or higher than the pressure P_a on the side of the low-pressure accumulator 71a.

At time ti2, when the hydraulic pressure Pw_F of the hydraulic brake 38a for the right front wheel RF becomes equal to or higher than the pressure P_a on the side of the low-pressure accumulator 71a (S31/Yes), the brake ECU 90 opens the first pressure reducing valve 54aa and the first pressure reducing valve 54aa. is closed. After time ti2, the brake ECU 90 drives the pump 44a as required. As a result, the brake fluid flows from the hydraulic brake 38a side of the right front wheel RF to the low pressure accumulator 71a side without flowing through the first pressure reducing valve 54aa from the low pressure accumulator 71a side to the hydraulic brake 38a side of the right front wheel RF. and flow.

After that, the opening degree of the first pressure increasing valve 58aa is adjusted according to the target value of the pressure in the wheel cylinder of the hydraulic brake 38b of the left rear wheel LR, and the hydraulic brake generated in the hydraulic brake 38b of the left rear wheel LR is adjusted. The force is adjusted (step S15 of the flow chart shown in FIG. 7). In this state, the brake fluid supplied to the hydraulic brake 38a of the right front wheel RF is supplied to the low pressure accumulator 71a via the first pressure reducing valve 54aa, so that the hydraulic brake 38a of the right front wheel RF A relatively small hydraulic braking force is generated according to the spring force of the accumulator 71a.

FIG. 11 shows a timing chart of a reference example for quickly opening the first pressure reducing valve 54aa when the braking force requested by the driver cannot be covered by the regenerative braking force alone. At time ti1 when the braking force requested by the driver cannot be covered by the regenerative braking force alone, the second pressure reducing valve 54ba is closed and the first pressure reducing valve 54ba is closed to increase the hydraulic pressure Pw_R of the hydraulic brake 38b of the left rear wheel LR. The pressure reducing valve 54aa is opened. In this case, since the hydraulic pressure Pw_F of the hydraulic brake 38a for the right front wheel RF is lower than the pressure P_a on the low pressure accumulator 71a side, the brake fluid moves the first pressure reducing valve 54aa from the low pressure accumulator 71a side to the right front wheel RF. It will flow to the hydraulic brake 38a side.

As described above, in the vehicle brake device 100 according to the present embodiment, when the state in which only the regenerative braking force is generated is shifted to the state in which the hydraulic braking force is generated together with the regenerative braking force, the right front wheel The first pressure reducing valve 54aa is opened when the hydraulic pressure of the RF hydraulic brake 38a becomes equal to or higher than the pressure on the low pressure accumulator 71a side. Therefore, the brake fluid does not flow from the low pressure accumulator 71a side to the hydraulic brake 38a side of the right front wheel RF via the first pressure reducing valve 54aa, and the filter corresponding to the flow is removed from the first pressure reducing valve 54aa. can be omitted.

FIG. 12 is a flowchart of the processing performed when the brake pedal is suddenly released in a state where the braking force is distributed to the regenerative braking force and the hydraulic pressure braking force in step S15 of the flowchart shown in FIG. show.

The brake ECU 90 determines whether or not the brake pedal 11 is suddenly released while the hydraulic braking force is being generated (step S41). For example, based on the stroke signal supplied from the electric booster 13, the brake ECU 90 determines whether the rate of increase in the stroke amount has become negative and the master cylinder pressure has fallen below the pressure in the low pressure accumulator 71a. determine. Master cylinder pressure is detected based on the sensor value of the master cylinder hydraulic pressure sensor 24 . A value preset according to the spring constant of the spring of the low-pressure accumulator 71a is used as the pressure P_a on the side of the low-pressure accumulator 71a. As described above, the pressure P_a on the low pressure accumulator 71a side may be an actual measurement value or a model value.

When the brake ECU 90 determines that the brake pedal 11 is suddenly released (S41/Yes), the first pressure reducing valve 54aa is closed (step S43). On the other hand, if the brake ECU 90 does not determine that the brake pedal 11 has been suddenly released (S41/No), it opens the first pressure reducing valve 54aa or maintains the open state (step S45). The brake ECU 90 repeatedly executes the processes of steps S41 to S45. After the first pressure reducing valve 54aa is closed in step S43, the first pressure reducing valve 54aa may be opened after an appropriate amount of time that has been determined by simulation has elapsed.

As described above, in the vehicle brake device 100 according to the present embodiment, when the brake pedal 11 is suddenly released while the regenerative braking force and the hydraulic pressure braking force are being generated, the first pressure reducing valve 54aa is closed. After that, when the hydraulic pressure of the hydraulic brake 38a for the right front wheel RF becomes higher than the pressure of the low-pressure accumulator 71a, the first pressure reducing valve 54aa is opened again. Therefore, the brake fluid does not flow from the low pressure accumulator 71a side to the hydraulic brake 38a side of the right front wheel RF via the first pressure reducing valve 54aa, and the filter corresponding to the flow is removed from the first pressure reducing valve 54aa. can be omitted.

As described above, according to the vehicle brake device 100 according to the present embodiment, it is possible to reduce the number of filters provided in the pressure reducing valve of the hydraulic brake on the front wheel side. Therefore, manufacturing costs can be reduced. In addition, since the number of parts is reduced, it is possible to prevent an increase in variations of pressure reducing valves due to differences in vehicles and brake systems.

Furthermore, if a filter for collecting foreign matter moving from the low-pressure accumulator 71a side to the hydraulic brake 38a side on the front wheel side becomes unnecessary, the hydraulic pressure of the front wheels can be reduced while minimizing the hydraulic braking force on the rear wheels. Adjusts the braking force so that the sum of the hydraulic braking force and the regenerative braking force matches the braking force required by the driver. can do.

Although the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention belongs can conceive of various modifications or modifications within the scope of the technical idea described in the claims. It is understood that these also naturally belong to the technical scope of the present invention.

For example, the hydraulic circuit 1 described in the above embodiment includes the dampers 73a and 73b in the first hydraulic circuit 28 and the second hydraulic circuit 30, respectively, but these dampers 73a and 73b are omitted. may have been

Further, in the above embodiment, the master cylinder pressure detected by the master cylinder pressure sensor 24 is used to calculate the actual caliper volume, but the present invention is not limited to this example. If the actual caliper volume can be calculated, a wheel cylinder pressure sensor is provided between the wheel cylinder of the hydraulic brake 38a on the front wheel side and the first pressure increase valve 58aa, and the wheel cylinder pressure is used instead of the master cylinder pressure. may

In the above embodiment, the hydraulic pressure of the hydraulic brake 38a on the front wheel side is calculated based on the flow rate of the brake fluid supplied to the hydraulic brake 38a, but the present invention is not limited to this example. A wheel cylinder hydraulic pressure sensor may be provided between the wheel cylinder of the hydraulic brake 38a on the front wheel side and the first pressure increase valve 58aa to detect the hydraulic pressure of the hydraulic brake 38a on the front wheel side.

In the above-described embodiment, when reducing the hydraulic pressure of the hydraulic brake 38a on the front wheel side, the brake ECU 90 continuously gradually increases the opening of the first pressure increase valve 58aa on the front wheel side, and then , the first pressure reducing valve 54aa is opened, but the present invention is not limited to such an example. If the hydraulic pressure of the hydraulic brake 38a on the front wheel side can be gradually reduced continuously, the opening of the first pressure increasing valve 58aa on the front wheel side is increased after the first pressure reducing valve 54aa on the front wheel side is opened. may

28 First hydraulic circuit 30 Second hydraulic circuit 34a Suction valve 36a Circuit control valve 38a First hydraulic brake 38b Second hydraulic brake 44a Pump , 54aa... first pressure reducing valve, 54ba... second pressure reducing valve, 58aa... first pressure increasing valve (regulating valve), 58ba... second pressure increasing valve (regulating valve), 71a... low pressure accumulator, 96... pump motor , 100... vehicle brake device, 121... battery, 123... inverter, 125... drive motor

Claims (5)

A first hydraulic brake (38a) that generates a hydraulic braking force on the front wheel (RF), a second hydraulic brake (38b) that generates a hydraulic braking force on the rear wheel (LR), and a front wheel (RF a regenerative brake (125) that converts the kinetic energy of ) to generate a regenerative braking force, and is capable of distributing the braking force to the hydraulic braking force and the regenerative braking force,
a first adjusting valve (58aa) for continuously adjusting the flow rate of the brake fluid supplied to the first hydraulic brake (38a);
a second regulating valve (58ba) for continuously adjusting the flow rate of the brake fluid supplied to the second hydraulic brake (38b);
a first pressure reducing valve (54aa) for reducing the hydraulic braking force of the first hydraulic brake (38a);
a second pressure reducing valve (54ba) for reducing the hydraulic braking force of the second hydraulic brake (38b);
an accumulator (71a) to which brake fluid is supplied when pressure is reduced by the first pressure reducing valve (54aa) or the second pressure reducing valve (54ba);
a control device (90) that controls the first regulating valve (58aa), the first pressure reducing valve (54aa), the second regulating valve (58ba) and the second pressure reducing valve (54ba); prepared,
The control device (90)
While only the regenerative braking force is generated, the first adjusting valve (58aa) and the first pressure reducing valve (54aa) are closed, while the second adjusting valve (58ba) and the second pressure reducing valve (54aa) are closed. opening the pressure reducing valve (54ba) and supplying brake fluid to the accumulator (71a) through the second adjusting valve (58ba) and the second pressure reducing valve (54ba);
While the hydraulic braking force is generated together with the regenerative braking force, the second pressure reducing valve (54ba) is closed while the first pressure reducing valve (54aa) and the second regulating valve (58ba) are closed. ) in an open state, supplying brake fluid to the second hydraulic brake (38b),
By adjusting the flow rate of the brake fluid supplied to the accumulator (71a) through the first adjusting valve (58aa) and the first pressure reducing valve (54aa) by the first adjusting valve (58aa) Adjust the hydraulic brake force of the rear wheel (LR),
A brake system for a vehicle, wherein the first pressure reducing valve (54aa) is opened in a state where the pressure on the side of the first hydraulic brake (38a) is higher than the pressure on the side of the accumulator (71a). . When switching from a state in which only regenerative braking force is generated to a state in which regenerative braking force and hydraulic pressure braking force are generated,
The control device (90)
The first pressure reducing valve (54aa) is opened when the pressure on the side of the first hydraulic brake (38a) becomes higher than the pressure on the side of the accumulator (71a), The vehicle braking device according to claim 1 . When the brake pedal (11) is released from the state of generating regenerative braking force and hydraulic braking force,
The control device (90)
The first pressure reducing valve (54aa) is opened when the pressure on the side of the first hydraulic brake (38a) becomes higher than the pressure on the side of the accumulator (71a), The vehicle braking device according to claim 1 . The control device (90)
Whether or not the pressure on the side of the first hydraulic brake (38a) is greater than the pressure on the side of the accumulator (71a) is determined by the return speed of the brake pedal (11) and the master cylinder that stores the brake fluid. 4. The vehicle braking device according to claim 3 , wherein the determination is made based on the pressure in (14). A first hydraulic brake (38a) that generates a hydraulic braking force on the front wheel (RF), a second hydraulic brake (38b) that generates a hydraulic braking force on the rear wheel (LR), and a front wheel (RF ) to generate regenerative braking force, and a first control valve ( 58aa), a second regulating valve (58ba) for continuously adjusting the flow rate of the brake fluid supplied to the second hydraulic brake (38b), and the hydraulic pressure of the first hydraulic brake (38a). A first pressure reducing valve (54aa) for reducing the braking force, a second pressure reducing valve (54ba) for reducing the hydraulic pressure braking force of the second hydraulic brake (38b), and the first pressure reducing valve ( 54aa) or an accumulator (71a) to which brake fluid is supplied when pressure is reduced by the second pressure reducing valve (54ba), the first adjusting valve (58aa), the first pressure reducing valve (54aa), the second A control device (90) that controls the adjustment valve (58ba) and the second pressure reducing valve (54ba), and is capable of distributing the braking force to the hydraulic braking force and the regenerative braking force ( 100) in the control method,
The control device (90)
While only the regenerative braking force is generated, the first adjusting valve (58aa) and the first pressure reducing valve (54aa) are closed, while the second adjusting valve (58ba) and the second pressure reducing valve (54aa) are closed. opening the pressure reducing valve (54ba) and supplying brake fluid to the accumulator (71a) through the second adjusting valve (58ba) and the second pressure reducing valve (54ba);
While the hydraulic braking force is generated together with the regenerative braking force, the second pressure reducing valve (54ba) is closed while the first pressure reducing valve (54aa) and the second regulating valve (58ba) are closed. ) in an open state, supplying brake fluid to the second hydraulic brake (38b),
By adjusting the flow rate of the brake fluid supplied to the accumulator (71a) through the first adjusting valve (58aa) and the first pressure reducing valve (54aa) by the first adjusting valve (58aa) Adjust the hydraulic brake force of the rear wheel (LR),
A brake system for a vehicle, wherein the first pressure reducing valve (54aa) is opened in a state where the pressure on the side of the first hydraulic brake (38a) is higher than the pressure on the side of the accumulator (71a). control method.

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