JP2020100317A - Vehicular braking device and control method of vehicular braking device - Google Patents

Abstract

To provide a braking device capable of improving energy utilization efficiency during regenerative cooperation of a front-wheel drive vehicle and improving stabilization of vehicle behavior.SOLUTION: A vehicular braking device includes: a first hydraulic braking (38a) of a front wheel (RF); a second hydraulic braking (38b) of a rear wheel (LR); and a regeneration brake for generating regenerative brake force by converting kinetic energy of the front wheel (RF). The vehicular braking device capable of distributing brake force to hydraulic braking force and regenerative brake force is configured to: hold a second pressure reduction valve (54ba) in a valve closing status; hold a first pressure reduction valve (54aa) and a second regulating valve (58ba) in the valve closing status; and regulate a flow quantity of brake fluid to a side of a first hydraulic braking (38a) by a first regulating valve (58aa) to regulate hydraulic braking force of the rear wheel (LR).SELECTED DRAWING: Figure 3

Description

The present invention relates to a vehicle brake device and a vehicle brake device control method.

Conventionally, a vehicle brake device includes a hydraulic brake that generates a hydraulic braking force by using a hydraulic pressure that is generated according to a brake operation of a driver, and a regenerative brake that generates a regenerative braking force. There is known a vehicle brake device 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").

The purpose of the regenerative brake used in the vehicle brake device is to convert the kinetic energy of the wheel at the time of braking into electric energy so as to effectively utilize the energy. The maximum regenerative braking force that can be regenerated by the regenerative brake 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 operating, 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 for performing regenerative coordination. For example, in Patent Document 1, it is provided between the hydraulic brakes of the front wheels and the hydraulic brakes of 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 changed. It is equipped with an adjustable adjustment valve and a pressure reducing valve capable of reducing the pressure of the brake fluid supplied to the hydraulic brakes of the rear wheels, and when reducing the hydraulic braking force of the hydraulic brakes of the front wheels, the adjustment valve is opened. There is disclosed a vehicular brake device in which the pressure reducing valve is opened while the pressure is continuously increased.

International Publication No. 2012/086290

However, when the vehicle brake device disclosed in Patent Document 1 is applied to a front-wheel drive hybrid vehicle or an electric vehicle that drives the front wheels of the vehicle by the driving force output from the internal combustion engine or the drive motor, regenerative cooperation is performed. During the operation, the rear wheels are controlled so that no braking force is generated. Specifically, in the vehicle brake device disclosed in Patent Document 1, in generating a hydraulic braking force together with a regenerative braking force acting on the front wheels, an adjusting valve for supplying brake fluid to the hydraulic brakes for the front wheels and By holding the pressure reducing valve that reduces the hydraulic braking force on the rear wheels in the open state and controlling the opening of the adjustment valve on the rear wheel side, the hydraulic pressure on the front wheels can be generated without generating the hydraulic braking force on the rear wheels. The braking force is adjusted so that the sum of the hydraulic braking force and the regenerative braking force matches the braking force required by the driver.

Therefore, the ratio of the braking force distributed to the front wheels becomes excessively large, and the behavior of the vehicle may become unstable like an understeer state. When the vehicle is in an understeer state, 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 braking force of the rear wheels, which may reduce the energy utilization efficiency. There is.

The present invention has been made in view of the above problems, and in a front-wheel drive hybrid vehicle or an electric vehicle, the braking force at the time of regenerative cooperation is distributed to the front and rear wheels to improve the energy utilization efficiency and to improve the vehicle behavior. (EN) Provided are a vehicle brake device capable of improving stabilization and a control method thereof.

According to one aspect of the present invention, a first hydraulic brake that generates hydraulic braking force on the front wheels, a second hydraulic brake that generates hydraulic braking force on the rear wheels, and kinetic energy of the front wheels are converted. And a regenerative brake that generates a regenerative braking force, and is capable of distributing the braking force to the hydraulic braking force and the regenerative braking force, the brake fluid being supplied to the first hydraulic brake. Adjusting valve for continuously adjusting the flow rate of the first hydraulic brake, a second adjusting valve for continuously adjusting the flow rate of the brake fluid supplied to the second hydraulic brake, and a hydraulic pressure for the first hydraulic brake. A first pressure reducing valve for reducing the braking force, a second pressure reducing valve for reducing the hydraulic braking force of the second hydraulic brake, a first adjusting valve, a first reducing valve, and a second adjusting valve. And a control device for controlling the operation of the second pressure reducing valve, wherein the control device holds the second pressure reducing valve in a closed state and opens the first pressure reducing valve and the second adjusting valve in an open state. A vehicle braking device is provided which adjusts the hydraulic braking force of the rear wheels by holding the hydraulic pressure by the first adjusting valve and adjusting the flow rate of the brake fluid toward the first hydraulic brake side by the first adjusting valve.

According to another aspect of the present invention, a first hydraulic brake that generates hydraulic braking force on the front wheels, a second hydraulic brake that generates hydraulic braking force on the rear wheels, and a movement of the front wheels. A regenerative brake that converts energy to generate a regenerative braking force, a first adjustment valve that continuously adjusts the flow rate of the brake fluid that is supplied to the first hydraulic brake, and a second hydraulic brake that is supplied 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 are provided. A second pressure reducing valve for reducing the pressure and a control device for controlling the first adjusting valve, the first reducing valve, the second adjusting valve and the second reducing valve are provided, and the hydraulic braking force and the regenerative braking force are provided. In a method for controlling a vehicle brake device capable of distributing a braking force to and, a control device holds a second pressure reducing valve in a closed state and a first pressure reducing valve and a second adjusting valve in an open state. Provided is a method for controlling a vehicle brake device, which holds and controls the flow rate of brake fluid to the first hydraulic brake side by the first adjusting valve to adjust the hydraulic braking force of the rear wheels.

As described above, according to the present invention, in a front-wheel drive hybrid vehicle, the braking force at the time of regenerative coordination is distributed to the front and rear wheels to improve energy utilization efficiency and improve vehicle behavior stabilization. You can

It is a schematic diagram showing an example of composition of a brake equipment for vehicles concerning an embodiment of the invention. It is explanatory drawing of the hydraulic circuit which comprises the hydraulic brake in the vehicle brake device which concerns on the same embodiment. It is explanatory drawing which shows the state of a hydraulic circuit while a braking force is produced only with a regenerative braking force. It is explanatory drawing which shows the state of a hydraulic circuit while a braking force is distributed to the hydraulic braking force and the regenerative braking force. It is a flow chart which shows processing by a brake ECU of the brake equipment for vehicles concerning the embodiment. It is a timing chart which shows an example of operation of a brake equipment for vehicles.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and the drawings, constituent elements having substantially the same functional configuration are designated by the same reference numerals, and a duplicate description will be omitted.

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

The vehicle brake device 100 according to the present 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 required 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 traveling and functions as a generator during braking to generate a regenerative braking force on the front wheels F. The drive 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 regenerated electric power from the drive motor 125.

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

That is, the vehicle brake device 100 according to the present embodiment can generate the regenerative braking force and the hydraulic braking force on the front wheels F, and can generate the 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 CAN (Controller Area Network). The brake ECU 90 controls the regenerative braking force generated on 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 on the maximum value of the regenerative braking force that can be output at that time.

The brake ECU 90 or the motor ECU 110 may be partially or wholly configured by, for example, a microcomputer, a microprocessor unit, or the like, or may be configured by updatable firmware or the like. Further, a 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 the 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 that detects the hydraulic pressure in the master cylinder 14 (master cylinder pressure), the brake ECU 90 receives each wheel RF. , LR, LF, RR, the sensor signals from a wheel speed sensor or the like (not shown) indicating the rotation speeds are input (see FIG. 2).

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

The 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 provided with two brake systems, and is applied to a so-called X-type piping type hydraulic circuit that brakes one front wheel and each rear wheel diagonally opposite to the front wheel in each system as one set. It The brake fluid pressure circuit 1 can be widely applied to vehicles including not only four-wheeled vehicles but also two-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. In the master cylinder 14, two pressurizing chambers defined by a primary piston and a secondary piston are formed. Each piston is pressed in response to the driver's depression operation of the brake pedal, and the brake fluid moves into the hydraulic circuit 1 via the hydraulic port communicating with each pressurizing chamber.

The booster 13 is connected to the brake pedal 11 side via the input rod 15, and the amplified pedal force is transmitted to the master cylinder 14 via the push rod connected to the primary piston. In the present embodiment, an electric booster is used as the booster 13.

From the hydraulic pressure ports communicating with the two pressurizing chambers of the master cylinder 14, the first hydraulic circuit 28 and the second hydraulic circuit 28 are respectively directed toward the hydraulic brakes 38a to 38d of the wheels RF, LR, LF, RR, respectively. The pressure circuit 30 extends. The hydraulic circuit 1 of the vehicle brake device according to the present embodiment is of an X-type piping system, and the wheel cylinder of the hydraulic brake 38a for the right front wheel RF and the wheel cylinder of the hydraulic brake 38b for the left rear wheel LR are Brake fluid is supplied through the hydraulic circuit 28 of No. 1. Further, brake fluid is supplied 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 via the second hydraulic circuit 30. As a result, each of the hydraulic brakes 38a to 38d can generate a braking force on each wheel RF, LR, LF, RR by the 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. Hereinafter, the first hydraulic circuit 28 will be briefly described, and the description of the second hydraulic circuit 30 will be omitted.

The first hydraulic circuit 28 includes, as electromagnetic valves, a normally open type linear controllable circuit control valve 36a, a normally closed type on-off controlled intake valve 34a, and a normally open type linearly controllable pressure increasing valve. (Adjusting valves) 58aa and 58ba, and pressure reducing valves 54aa and 54ba that are normally closed and are 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. The number of pumps 44a is not limited to one.

The first pressure increasing valve 58aa and the 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. The second pressure increasing valve 58ba and the 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 increasing 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 the brake fluid from the circuit control valve 36a side to the wheel cylinder side of the hydraulic brake 38a for the right front wheel RF. The first pressure increasing valve 58aa is provided with a check valve that allows the brake fluid to flow from the hydraulic brake 38a side to the circuit control valve 36a side while limiting the flow in the opposite direction when the first pressure increasing valve 58aa is closed. With a bypass flow path.

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

The second pressure increasing valve 58ba of the left rear wheel LR is provided between the circuit control valve 36a and the hydraulic brake 38b of 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 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 when the second pressure increasing valve 58ba is closed. With a bypass flow path.

The second pressure reducing valve 54ba of the left rear wheel LR is a solenoid valve capable of switching the valve only to a fully open or fully closed state, and is provided between the wheel cylinder of the hydraulic brake 38b of the left rear wheel LR and the low pressure accumulator 71a. It is provided in. The second pressure reducing valve 54ba reduces the brake fluid supplied to the wheel cylinder of the hydraulic brake 38b for the left rear wheel LR in the open state. The second pressure reducing valve 54ba can adjust 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 by intermittently repeating the opening and closing of the valve.

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

The second hydraulic circuit 30 controls the hydraulic brake 38c for the left front wheel LF and the hydraulic brake 38d for the right rear wheel RR. The second hydraulic circuit 30 replaces the wheel cylinder of the hydraulic brake 38a of the right front wheel RF in the description of the first hydraulic circuit 28 with the wheel cylinder of the hydraulic brake 38c of the left front wheel LF, and replaces the wheel cylinder of the left rear wheel LR. The configuration is similar to that of 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 of the right rear wheel RR.

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

FIG. 3 shows a state of the first hydraulic circuit 28 while the braking force is generated only by the regenerative braking force, and FIG. 4 shows a state in which the braking force is distributed to the hydraulic braking force and the regenerative braking force. 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 maintained in the open state, and the suction valve 34a, The first pressure increasing valve 58aa and the second pressure reducing valve 54aa are maintained in the closed state. 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 maintained in the open state, 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 drag torque is not generated by the residual pressure due to the spring force of the low pressure accumulator 71a and the hydraulic braking force does not act on the right front wheel RF. Has been.

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 maintained in the open state. The suction valve 34a and the second pressure reducing valve 54ba are kept closed. Then, the flow rate of the brake fluid supplied to the hydraulic brake 38a side of the right front wheel RF is adjusted by adjusting the opening degree of the first pressure increasing valve 58aa, and 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 maintained in the open state, 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, drag torque is generated in the hydraulic brake 38a of the front right wheel RF by the residual pressure due to the spring force of the low pressure accumulator 71a, and a relatively small hydraulic braking force is generated. Therefore, the regenerative braking force and the hydraulic braking force generated on the right front wheel RF and the hydraulic braking force generated on the left rear wheel LR exert a balanced braking force on the front and rear wheels. The maximum regenerative braking force that can be regenerated by the regenerative brake is limited by the vehicle speed during braking of the vehicle and the state of charge of the battery.Therefore, the remaining braking force obtained by subtracting the regenerative braking force from the driver's requested braking force is hydraulically adjusted. The opening degree 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, the regenerative braking force and the hydraulic braking force generated on the left front wheel LF and the hydraulic braking force generated on the right rear wheel RR exert a balanced braking force on the front and rear wheels. .. As a result, the braking force is distributed to the front wheels and the rear wheels, and an unstable behavior of the vehicle such as an understeer state due to an increase in the ratio of the braking force generated on the front wheels can be suppressed. Further, since it is not necessary to reduce the regenerative braking force in order to eliminate the unstable behavior of the vehicle, it is possible to suppress the reduction in energy utilization efficiency.

<4. Processing example>
Next, the regenerative cooperation processing by the brake ECU 90 of the vehicle brake device 100 according to the present embodiment will be described. FIG. 5 is a flowchart showing an example of processing by the brake ECU 90. In the vehicle brake device 100, the hydraulic braking force of the hydraulic brake 38b of the left rear wheel LR and the hydraulic brake 38d of the right rear wheel RR are appropriately adjusted according to the fluctuation of the maximum regenerative braking force that can be regenerated by the regenerative brake. Controlled. Hereinafter, 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, but the hydraulic pressure on the left front wheel LF on the second hydraulic circuit 30 side will be described. The brake 38c and the hydraulic brake 38d for the right rear wheel RR are also controlled in the same manner.

First, the brake ECU 90 determines whether or not the driver has requested the braking force (step S11). Specifically, the brake ECU 90 calculates the braking force required 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 preset, and the brake ECU 90 calculates the required braking force based on the map and the stroke amount. When the calculated required braking force is a positive value, the brake ECU 90 determines that the driver has requested the braking force.

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

The brake ECU 90 stores a map in which the correspondence between the stroke amount of the booster 13 and the braking force required by the driver is preset, and the brake ECU 90 stores the braking force required by the driver based on the map and the stroke amount. To calculate. Further, 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.

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

When the hydraulic braking force is required (S13/Yes), the brake ECU 90 controls the hydraulic braking force generated in the hydraulic brake 38b of the left rear wheel LR (step S15). Specifically, the brake ECU 90 stores a map in which the correspondence between the wheel cylinder pressure and the caliper volume is preset, and the brake ECU 90 stores the map and the master cylinder pressure detected by the master cylinder hydraulic pressure sensor 24. , The caliper volume at present (actual caliper volume) and the target value of caliper volume (target caliper volume) are calculated based on the target value of the wheel cylinder pressure.

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, while the intake 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 difference value obtained by subtracting the actual caliper volume from the target caliper volume.

On the other hand, when the difference obtained by subtracting the actual caliper volume from the target caliper volume is a negative value, the brake ECU 90 maintains the circuit control valve 36a, the first pressure reducing valve 54aa, and the second pressure increasing valve 58ba in the open state. On the other hand, the suction valve 34a and the second pressure reducing valve 54ba are maintained in the closed state. In this state, the brake ECU 90 gradually increases the opening degree of the first pressure increasing valve 58aa and stops the pump motor 96. As a result, the first pressure reducing valve 54aa is maintained in the open state and the second pressure reducing valve 54ba is maintained in the closed state, so that the pressure reduction of the hydraulic brake 38b of the left rear wheel LR is performed by the first pressure increasing valve. Adjusted by 58aa. In this way, when the regenerative braking force is increased while the hydraulic braking force is being applied to the hydraulic brake 38b of the left rear wheel LR, the brake fluid supplied to the hydraulic brake 38b of the left rear wheel LR is increased. The liquid 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 retained.

On the other hand, when the hydraulic braking force is not necessary (S13/No), the brake ECU 90 controls only the regenerative braking force without generating the hydraulic braking force (step S17). Specifically, the brake ECU 90 maintains the circuit control valve 36a, the second pressure increasing valve 58ba, and the second pressure reducing valve 54ba in the open state, while the intake valve 34a, the first pressure increasing valve 58aa, and the first pressure reducing valve. The valve 54aa is kept closed. Further, the pump motor 96 is deactivated.

As a result, although the brake fluid flowing from the master cylinder 14 into the first hydraulic circuit 28 is supplied to the hydraulic brake 38b side of the left rear wheel LR, the brake fluid is low in pressure via the second pressure reducing valve 54ba. It is supplied to the accumulator 71a. Therefore, a hydraulic pressure corresponding to the reaction force of the low pressure accumulator 71a is generated in the hydraulic brake 38b of the left rear wheel LR, but the hydraulic braking force is not generated by the hydraulic pressure, or is set to an extremely small value. You can When the process of step S17 is once performed via step S15, an extremely small value of hydraulic pressure is also generated in the hydraulic brake 38a of the front right 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 cooperation 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 obtained from the motor ECU 110. To determine. However, the method of determining whether or not to terminate the regenerative cooperation is not limited to this example.

If the brake ECU 90 does not determine to end the regenerative cooperative control (S19/No), the brake ECU 90 returns to step S11 and continues the process. On the other hand, when the brake ECU 90 determines to end the regenerative cooperative control (S19/Yes), the brake ECU 90 decreases the regenerative braking force while increasing the hydraulic braking force of the hydraulic brake 38a for the right front wheel RF (step S21). .. At this time, not only the hydraulic braking force of the hydraulic brake 38b of the left rear wheel LR is increased, but also the hydraulic braking force of the hydraulic brake 38a of the right front wheel RF is increased, so that the regenerative coordinated control is performed. 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). When 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 ends the regenerative cooperative control (step S25).

The vehicle brake device 100 according to the present embodiment uses the hydraulic braking force of the hydraulic brake of the rear wheel, not the front wheel on which the regenerative braking force is exerted, when generating the hydraulic braking force during the regenerative cooperative control. Give rise to. Therefore, it is possible to suppress an unstable behavior of the vehicle such as understeer caused by an increase in the braking force ratio on the front wheel side. Further, since the 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 it is possible to suppress the decrease in energy utilization efficiency.

FIG. 6 is a timing chart showing an example of the operation of the vehicle brake device 100. 6, in the graph of the braking force Tq and the time Time, the regenerative braking force (corresponding to the regenerative braking command value) is shown by the solid line as the regenerative torque Tq_E, and the braking force required by the driver is shown by the broken line as the required torque Tq_D. Has been done. 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 shown by a solid line, and the hydraulic pressure Pw_F on the front wheel side is shown by a broken line.

As shown in the first region D in FIG. 6, while the required braking force Tq_D by the driver can be covered only by the regenerative braking force Tq_E, the first pressure increasing valve (EV_f) 58aa on the front wheel side and the first pressure reducing valve (AV_f). 54aa is closed. Further, the second pressure increasing valve (EV_r) 58ba and the second pressure reducing valve (AV_r) 54ba on the rear wheel side are opened. Specifically, in the region D, the required braking force Tq_D due to the depression of the pedal increases, and the required regenerative braking force also increases accordingly. At this time, an extremely small hydraulic pressure corresponding to the reaction force of the low pressure accumulator 71a is generated in the hydraulic brake 38b of the left rear wheel LR, and the hydraulic braking force is not generated or is extremely small. The second pressure reducing valve 54ba on the rear wheel side is opened until the required regenerative braking force becomes larger than the maximum regenerative braking force and the target value of the pressure in the wheel cylinder of the hydraulic brake for the rear wheel becomes a positive value. The valve state is maintained. As a result, the brake fluid corresponding to the pedal operation amount is discharged to the low pressure accumulator 71a.

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

When the maximum regenerative braking force starts to increase, the difference between the target caliper volume and the actual caliper volume becomes negative, so that the opening degree of the first pressure increasing valve (EV_f) 58aa on the front wheel side is continuously increased little by little. , The first pressure reducing valve 54aa on the front wheel side is opened (region C). When the maximum regenerative braking force stops increasing, the front wheel-side first pressure increasing valve 58aa is maintained in the closed state, and the front wheel-side first pressure reducing valve 54aa is maintained in the open state (region B).

After that, when the maximum regenerative braking force begins 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 the front wheel side opening degree is adjusted. 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 hydraulic brake 38a and the hydraulic brake 38b on the rear wheel side have the same pressure. After that, the first pressure increasing valve 58aa on the front wheel side is fully opened, and the hydraulic pressure is controlled only by the pump 44a. When the hydraulic braking force of the front wheel side hydraulic brake 38a and the rear wheel side hydraulic brake 38b are both zero (area D), when transitioning to the area E, the front wheel side first The pressure increasing 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 become the hydraulic pressure corresponding to the braking force Tq_D requested by the driver, the operation of the pump 44a is stopped. (Region A). During this period, the opening degree of the first pressure increasing valve 58aa on the front wheel side is controlled based on the volume states of the front wheel hydraulic brake 38a and the rear wheel hydraulic brake 38b, and the respective hydraulic brakes 38a, 38b are controlled. Fluid pressure is adjusted.

The preferred embodiments of the present invention have been described above in detail with reference to the accompanying drawings, but the present invention is not limited to these examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

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

Further, in the above embodiment, the master cylinder pressure detected by the master cylinder hydraulic pressure sensor 24 is used in calculating 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 hydraulic pressure sensor is provided between the wheel cylinder of the hydraulic brake 38a on the front wheel side and the first pressure increasing valve 58aa, and the wheel cylinder pressure is used instead of the master cylinder pressure. May be.

Further, 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 and gradually increases the opening degree of the first pressure increasing valve 58aa on the front wheel side and then the front wheel side. Although the first pressure reducing valve 54aa is opened, the present invention is not limited to this example. If the hydraulic pressure of the hydraulic brake 38a on the front wheel side can be continuously and gradually reduced, after opening the first pressure reducing valve 54aa on the front wheel side, the opening degree of the first pressure increasing valve 58aa on the front wheel side can be increased. May be.

28... 1st hydraulic circuit, 30... 2nd hydraulic circuit, 34a... Intake valve, 36a... Circuit control valve, 38a... 1st hydraulic brake, 38b... 2nd 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 braking device, 121... Battery, 123... Inverter, 125... Driving motor

Claims (5)

A first hydraulic brake (38a) that generates hydraulic braking force on the front wheels (RF), a second hydraulic brake (38b) that generates hydraulic braking force on the rear wheels (LR), and a front wheel (RF). A regenerative brake (125) for converting the kinetic energy of) to generate a regenerative braking force, and capable of distributing the braking force to the hydraulic braking force and the regenerative braking force.
A first regulating valve (58aa) for continuously regulating the flow rate of the brake fluid supplied to the first hydraulic brake (38a);
A second adjusting 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);
A controller (90) for controlling the operations of the first adjusting valve (58aa), the first pressure reducing valve (54aa), the second adjusting valve (58ba) and the second pressure reducing valve (54ba). ,,
The control device (90) is
The second pressure reducing valve (54ba) is held in the closed state, and the first pressure reducing valve (54aa) and the second adjusting valve (58ba) are held in the open state, and the first adjusting valve is held. (58aa) adjusts the flow rate of the brake fluid to the side of the first hydraulic brake (38a) to adjust the hydraulic braking force of the rear wheels (LR). .. The control device (90) is
When no hydraulic braking force is generated in either the first hydraulic brake (38a) or the second hydraulic brake (38b), the first regulating valve (58aa) and the first pressure reducing valve The vehicle according to claim 1, characterized in that (54aa) is held in a closed state, and the second adjusting valve (58ba) and the second pressure reducing valve (54ba) are held in an open state. Brake device. The control device (90) is
The vehicle brake device according to claim 1, wherein the first pressure reducing valve (54aa) is held in a closed state when increasing the regenerative braking force. The control device (90) is
When the hydraulic braking force of the first hydraulic brake (38a) is reduced, the first pressure reducing valve (54aa) is opened and supplied to the first hydraulic brake (38a). The vehicle brake device according to any one of claims 1 to 3, wherein the brake fluid is supplied to the accumulator (71a). A first hydraulic brake (38a) that generates hydraulic braking force on the front wheels (RF), a second hydraulic brake (38b) that generates hydraulic braking force on the rear wheels (LR), and a front wheel (RF). ) To convert the kinetic energy to generate a regenerative braking force, and a first adjusting valve () for continuously adjusting the flow rate of the brake fluid supplied to the first hydraulic brake (38a). 58aa), a second adjusting 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 braking force of the second hydraulic brake (38b), and the first adjusting valve ( 58aa), the first pressure reducing valve (54aa), the second regulating valve (58ba) and the second pressure reducing valve (54ba), and a controller (90) for controlling the hydraulic braking force. In a control method of a vehicle brake device (100) capable of distributing a braking force to a regenerative braking force,
The control device (90) is
The second pressure reducing valve (54ba) is held in the closed state, and the first pressure reducing valve (54aa) and the second adjusting valve (58ba) are held in the open state, and the first adjusting valve is held. (58aa) adjusts the flow rate of the brake fluid to the side of the first hydraulic brake (38a) to adjust the hydraulic braking force of the rear wheels (LR). Control method.

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