JP7188127B2 - Braking control device - Google Patents

Description

The present invention relates to a braking control device.

2. Description of the Related Art Conventionally, as a braking device for a vehicle, there is a technique of applying braking force to each wheel using hydraulic pressure generated by an upstream mechanism (master cylinder, etc.). In such a braking device, for example, when performing ABS (Antilock Brake System) control, the brake fluid in the wheel cylinder of each wheel is moved to a reservoir as appropriate while continuing to pressurize the brake fluid by an upstream mechanism. to adjust the braking force to prevent locking of each wheel.

When the brake fluid in the reservoir continues to be pressurized by the upstream mechanism, when the brake fluid in the reservoir reaches a predetermined amount or more, the motor is driven to operate the pump to pump out the brake fluid in the reservoir to a predetermined level. Discharge into the flow path.

JP 2016-159678 A

However, in the conventional technology described above, when the motor heats up due to continuous driving and reaches a predetermined temperature, it is necessary to stop functions such as braking control in order to protect the system. And the function could not be resumed until the motor cooled down to some extent.

SUMMARY OF THE INVENTION Accordingly, one of the objects of the present invention is to provide a braking control device capable of suppressing continuous driving of a motor for operating a pump in a braking control state of a vehicle.

The braking control device of the present invention includes, for example, a wheel cylinder provided for each wheel of a vehicle for generating a braking force by a brake fluid pressure, pressurizing means provided in a flow path connected to the wheel cylinder, A braking control device for controlling a braking device comprising pressure means and hydraulic pressure adjusting means provided between the wheel cylinder. In the braking device, the hydraulic pressure adjusting means has a first pressure adjusting valve, a second pressure adjusting valve, a reservoir, a pump, and a motor. The first pressure regulating valve is provided in a flow path connecting the wheel cylinder and the pressurizing means. The second pressure regulating valve is provided in a flow path connecting the wheel cylinder and the reservoir. The reservoir is arranged at a position connected to the wheel cylinder via the second pressure regulating valve and connected to the pressurizing means and the first pressure regulating valve via a connecting passage, and the brake It has a mechanism that presses the movable part with a predetermined pressure in a direction to decrease the volume of the reservoir chamber that stores the liquid. The pump pumps up the brake fluid in the reservoir and discharges it to a predetermined position in a passage connecting the pressurizing means and the wheel cylinder. The motor operates the pump. The braking control device is configured such that, in a braking control state in which the braking force of each wheel is controlled in accordance with the running state, the brake fluid pressure of all the wheel cylinders is either maintained or reduced, and all wheels are in a non-increased state. If it is determined that all wheels are in the non-increase state, the motor is stopped, the first pressure regulating valve is closed, and the pressure generated by the pressurizing means is reduced. A control section is provided for executing motor pumping suppression control to reduce the pressure generated in the reservoir to less than the predetermined pressure.

Further, in the braking control device of the present invention, for example, when the control unit determines that the all-wheel non-increase state is not in effect, the pressurizing means generates a predetermined brake fluid pressure.

Further, in the braking control device of the present invention, for example, the hydraulic pressure adjusting means includes an introduction valve in the connection flow path, and when the introduction valve is open, the connection flow path is opened, and the introduction valve is closed. The connection passage is blocked in the state, and the control unit opens the introduction valve during execution of the motor pumping suppression control.

Further, in the braking control device of the present invention, for example, when the controller determines that the amount of brake fluid stored in the reservoir is equal to or greater than a predetermined amount, the controller drives the motor without executing the motor pumping suppression control. .

Further, in the braking control device of the present invention, for example, the braking device synchronizes the pressure increasing, holding, and decreasing operations by the hydraulic pressure adjusting means for at least two or more of the wheels.

FIG. 1 is a schematic diagram showing a schematic configuration of a vehicle according to the first embodiment. FIG. 2 is a diagram showing a schematic configuration of the brake control section of the first embodiment. FIG. 3 is a schematic diagram showing a vehicle running downhill. FIG. 4 is a sequence diagram showing the flow of control in the comparative example and the first embodiment. FIG. 5 is a flowchart showing processing by the brake ECU of the first embodiment. FIG. 6 is a flowchart showing processing by the brake ECU of the second embodiment. FIG. 7 is a diagram showing a schematic configuration of the brake control section of the third embodiment.

Exemplary embodiments (first to third embodiments) of the present invention are disclosed below. The configurations of the embodiments shown below and the actions and results (effects) brought about by the configurations are examples. The present invention can be realized by configurations other than those disclosed in the following embodiments. Moreover, according to the present invention, at least one of various effects (including derivative effects) obtained by the configuration can be obtained.

(First embodiment)
FIG. 1 is a schematic diagram showing a schematic configuration of a vehicle 100 according to the first embodiment. In the first embodiment, the vehicle 100 may be, for example, an automobile (internal combustion engine automobile) having an internal combustion engine (engine 20) as a drive source, or an automobile (motor (not shown)) having an electric motor (not shown) as a drive source. an electric vehicle, a fuel cell vehicle, etc.), or a vehicle (hybrid vehicle) using both of them as drive sources. In addition, vehicle 100 can be equipped with various transmissions, and can be equipped with various devices (systems, parts, etc.) necessary for driving the internal combustion engine and the electric motor. Further, the system, number, layout, etc. of the devices related to the driving of the wheels in the vehicle 100 can be set variously. In the first embodiment, as an example, the vehicle 100 is a four-wheeled vehicle (four-wheeled vehicle) and has two left and right front wheels FL, FR and two left and right rear wheels RL, RR. In FIG. 1, the front in the vehicle front-rear direction (arrow FB) is the left side.

The vehicle 100 includes an engine 20, a brake control unit 30 (braking device), an imaging device 51, a radar device 52, a brake switch 42, a brake pedal stroke sensor 48, a pedaling force sensor 49, and an accelerator pedal stroke sensor 47. , a longitudinal acceleration sensor 43 , and a control device 40 .

The vehicle 100 also includes wheel cylinders Wfr, Wfl and wheel speed sensors 41fr, 41fl corresponding to the left and right front wheels FR, FL, respectively. Further, wheel cylinders Wrr, Wrl and wheel speed sensors 41rr, 41rl are provided corresponding to the two left and right rear wheels RR, RL, respectively. Hereinafter, the wheel speed sensors 41fr, 41fl, 41rr, and 41rl will be collectively referred to as "wheel speed sensors 41". Moreover, when collectively referring to the wheel cylinders Wfr, Wfl, Wrr, and Wrl, they will be referred to as "wheel cylinder W".

The vehicle 100 has a basic configuration as the vehicle 100 in addition to the configuration shown in FIG. Omit as appropriate.

The imaging device 51 is, for example, a digital camera incorporating an imaging device such as a CCD (Charge Coupled Device) or a CIS (CMOS Image Sensor). The radar device 52 is, for example, a millimeter wave radar device.

The wheel speed sensor 41 outputs a signal having a pulse each time the wheel corresponding to each wheel speed sensor 41 rotates by a predetermined angle.

The accelerator pedal stroke sensor 47 is provided on the accelerator pedal AP and detects the amount of depression (stroke amount) of the accelerator pedal AP by the driver.

The brake switch 42, brake pedal stroke sensor 48, and pedaling force sensor 49 are all provided on the brake pedal BP. The brake switch 42 outputs a brake operation signal indicating whether or not the driver has operated the brake pedal BP. Specifically, the brake switch 42 outputs an ON (High) brake operation signal when the brake pedal BP is operated, and outputs an OFF (Low) brake operation signal when the brake pedal BP is not operated. Outputs operation signals. The brake pedal stroke sensor 48 detects the depression amount (stroke amount) of the brake pedal BP by the driver. A pedaling force sensor 49 detects a brake pedaling force or a pedal actuation force when the brake pedal BP is depressed.

The longitudinal acceleration sensor 43 detects acceleration in the longitudinal direction of the vehicle body (longitudinal acceleration) and outputs a signal representing the longitudinal acceleration.

The engine 20 outputs power according to the operation of the accelerator pedal AP by the driver. The brake control unit 30 generates braking force by brake fluid pressure on each wheel FR, FL, RR, RL according to a command from the brake ECU 12 (control unit). The brake control unit 30 generates brake fluid pressure corresponding to the amount of operation of the brake pedal BP, and supplies the brake fluid pressure to the wheel cylinders Wfr, Wfl, Wrr, and Wrl respectively arranged on the wheels FR, FL, RR, and RL. are each adjustable.

The control device 40 receives signals, data, and the like from each part of the vehicle 100 and controls each part of the vehicle 100 . The control device 40 mainly includes a brake ECU (Electronic Control Unit) 12 and an engine ECU 13, as shown in FIG.

The engine ECU 13 manages various controls of the engine 20 such as fuel injection control and intake air amount adjustment control.

The brake ECU 12 manages adjustment control of the braking torque for the host vehicle, adjustment control of the braking torque for each of the wheels FR, FL, RR, and RL. The brake ECU 12 detects the vehicle body speed of the own vehicle based on a detection signal from at least one wheel speed sensor 41 among the wheel speed sensors 41 provided for each of the wheels FR, FL, RR, and RL. Based on the detection signal of , the acceleration of the vehicle is calculated and sent to other ECUs. Further, the brake ECU 12 detects the amount of operation of the brake pedal BP based on one or both of the signals from the brake pedal stroke sensor 48 and the depression force sensor 49 described above. Details of the brake ECU 12 will be described later.

Each ECU is configured as a computer, and includes an arithmetic processing unit (not shown) such as a CPU (Central Processing Unit), and a storage unit such as ROM (Read Only Memory), RAM (Random Access Memory), and flash memory. .

The arithmetic processing unit reads a program stored (installed) in a nonvolatile storage unit (eg, ROM, flash memory, etc.), executes arithmetic processing according to the program, and functions as each ECU. The storage unit also stores data (tables (data groups), functions, etc.) used in various calculations related to control, calculation results (including values in the middle of calculation), and the like.

Note that the configuration of the vehicle 100 described above is merely an example, and can be implemented with various modifications. Well-known devices can be used as individual devices that configure vehicle 100 . Further, each configuration of vehicle 100 can be shared with other configurations.

Next, with reference to FIG. 2, the details of the brake control unit 30 will be described. FIG. 2 is a diagram showing a schematic configuration of the brake control section 30 of the first embodiment. The brake control unit 30 includes a brake fluid pressure generating unit 32 (pressurizing means) that generates a brake fluid pressure corresponding to the amount of operation of the brake pedal BP, and wheel cylinders Wfr that are arranged on the wheels FR, FL, RR, and RL, respectively. , Wfl, Wrr, Wrl, an FR brake fluid pressure adjusting unit 33, an FL brake fluid pressure adjusting unit 34, an RR brake fluid pressure adjusting unit 35, and an RL brake fluid pressure adjusting unit 36, It includes a recirculation brake fluid supply unit 37 and a master fluid pressure sensor 44 .

In the following, when the FR brake hydraulic pressure adjusting section 33, the FL brake hydraulic pressure adjusting section 34, the RR brake hydraulic pressure adjusting section 35, and the RL brake hydraulic pressure adjusting section 36 are not specifically distinguished, they are simply referred to as "fluid pressure adjusting section ” (liquid pressure adjusting means).

The brake hydraulic pressure generating section 32 is composed of a master cylinder MC and a piston driving section PP that displaces a piston in the master cylinder MC. The piston drive unit PP is, for example, a hydraulic mechanism that presses the piston in the master cylinder MC with hydraulic pressure accumulated using a pump to move the position of the piston to a predetermined position, or converts the rotation of the motor into direct motion. An electric mechanism is used to move the position of the piston in the master cylinder MC, which is connected to the master cylinder MC, to a predetermined position. The brake fluid pressure generating unit 32 generates master cylinder fluid pressure in the master cylinder MC by displacing the piston in the master cylinder MC with the piston driving unit PP according to the instruction from the brake ECU 12 .

The master cylinder MC has two systems of output ports consisting of a first port and a second port. The first master cylinder hydraulic pressure Pm is generated from the first port, and the second master cylinder hydraulic pressure Pm, which is substantially the same as the first master cylinder hydraulic pressure, is generated from the second port. Hereinafter, the master cylinder hydraulic pressure is also referred to as "MC hydraulic pressure".

Since the configuration and operation of the master cylinder MC and the piston driving part PP are well known, detailed description thereof will be omitted here. Then, the brake hydraulic pressure generator 32 generates the first MC hydraulic pressure and the second MC hydraulic pressure according to the operation amount of the brake pedal BP according to the instruction from the brake ECU 12 . Further, the brake hydraulic pressure generator 32 generates arbitrary first MC hydraulic pressure and second MC hydraulic pressure necessary for brake control according to instructions from the brake ECU 12, regardless of the amount of operation of the brake pedal BP.

Master hydraulic pressure sensor 44 detects the MC hydraulic pressure of master cylinder MC and sends a detection signal to control device 40 . Specifically, the master hydraulic pressure sensor 44 detects, as the MC hydraulic pressure, the second master cylinder hydraulic pressure Pm, which is substantially the same hydraulic pressure as the first master cylinder hydraulic pressure. Here, the master hydraulic pressure sensor 44 may be configured to detect the first master cylinder hydraulic pressure as the MC hydraulic pressure.

A normally open linear solenoid valve PC1 (first pressure regulating valve) is interposed between the first port of the master cylinder MC and the FR brake hydraulic pressure adjusting section 33 and the FL brake hydraulic pressure adjusting section 34 . Similarly, a normally open linear solenoid valve PC2 (first pressure regulating valve) is interposed between the second port of the master cylinder MC and the RR brake hydraulic pressure adjusting section 35 and the RL brake hydraulic pressure adjusting section 36. ing.

The FR brake hydraulic pressure adjusting unit 33 is composed of a pressure increasing valve PUfr, which is a 2-port, 2-position switching type normally open electromagnetic on-off valve, and a pressure reducing valve PDfr, which is a 2-port 2-position switching type normally closed electromagnetic on-off valve. . The pressure-increasing valve PUfr can communicate or disconnect the normally open linear solenoid valve PC1 (first pressure regulating valve) and the wheel cylinder Wfr. The pressure reducing valve PDfr can communicate and disconnect the wheel cylinder Wfr and the reservoir RS1. As a result, the brake fluid pressure (wheel cylinder fluid pressure Pwfr) in the wheel cylinder Wfr can be increased, maintained, and decreased by controlling the pressure increase valve PUfr and the pressure decrease valve PDfr. Hereinafter, the wheel cylinder hydraulic pressure is also referred to as "WC hydraulic pressure".

Further, the pressure increasing valve PUfr has a check valve CV1 that allows brake fluid to flow only in one direction from the wheel cylinder Wfr side of the pressure increasing valve PUfr to the normally open linear solenoid valve PC1 (first pressure regulating valve) side of the pressure increasing valve PUfr. are arranged in parallel. As a result, the WC hydraulic pressure Pwfr is quickly reduced even if the pressure increase valve PUfr is in the closed state when the brake pedal BP being operated is released.

Similarly, the FL brake fluid pressure adjusting unit 34, the RR brake fluid pressure adjusting unit 35, and the RL brake fluid pressure adjusting unit 36 are respectively provided with the pressure increasing valve PUfl and the pressure reducing valve PDfl, the pressure increasing valve PUrr and the pressure reducing valve PDrr, the pressure increasing valve PUrl and It is composed of a pressure reducing valve PDrl. By controlling these pressure increasing valves and pressure reducing valves, the brake fluid pressures (WC fluid pressures Pwfl, Pwrr, Pwrl) in the wheel cylinders Wfl, wheel cylinders Wrr and wheel cylinders Wrl are increased, maintained and decreased, respectively. can. Further, check valves CV2, CV3 and CV4 are arranged in parallel with each of the pressure increasing valves PUfl, PUrr and PUrl, respectively, and are capable of achieving the same function as the check valve CV1.

The recirculation brake fluid supply unit 37 includes a DC motor MT and two hydraulic pumps (gear pumps) HP1 and HP2 operated by the DC motor MT. The hydraulic pump HP1 pumps up the brake fluid in the reservoir RS1 that has been recirculated from the pressure reducing valves PDfr and PDfl, and pumps the pumped brake fluid through the check valve CV8 to the wheel cylinder Wfr and the wheel cylinder Wfl and the master cylinder MC. It is supplied to a predetermined position of the channel connecting the port. In the present embodiment, the FR brake fluid pressure adjustment unit 33 and the FL brake fluid pressure adjustment unit 34 on the flow path connecting the wheel cylinder Wfr and the wheel cylinder Wfl to the first port of the master cylinder MC, and the normally open linear solenoid valve PC1 (first pressure regulating valve). In addition, there is a first connecting passage connecting between the first port of the master cylinder MC and the normally open linear solenoid valve PC1 and the reservoir RS1, and the reservoir RS1 is emptied when the hydraulic pump HP1 is operated. In this case, brake fluid can be introduced into the hydraulic pump HP1 via the first connecting channel and the reservoir RS1.

Similarly, the hydraulic pump HP2 pumps up the brake fluid in the reservoir RS2 that has been recirculated from the pressure reducing valves PDrr and PDrl, and pumps the pumped brake fluid through the check valve CV11 to the wheel cylinders Wrr, Wrl and master cylinder MC. is supplied to a predetermined position of the flow path connecting the second port of the . In this embodiment, the RR brake fluid pressure adjustment unit 35 and the RL brake fluid pressure adjustment unit 36 on the flow path connecting the wheel cylinder Wrr and the wheel cylinder Wrl to the second port of the master cylinder MC, and the normally open linear solenoid valve PC1 (first pressure regulating valve). In order to reduce the pulsation of the discharge pressure of the hydraulic pumps HP1 and HP2, the hydraulic pressure circuit between the check valve CV8 and the normally open linear solenoid valve PC1 and between the check valve CV11 and the normally open linear solenoid valve PC2 are provided with dampers DM1 and DM2, respectively. In addition, there is a second connecting passage connecting between the second port of the master cylinder MC and the normally open linear solenoid valve PC2 and the reservoir RS2, and the reservoir RS2 is emptied when the hydraulic pump HP2 is operated. In this case, brake fluid can be introduced into the hydraulic pump HP2 via the second connecting channel and the reservoir RS2.

Also, to the normally open linear solenoid valve PC1, the FR brake hydraulic pressure adjusting part 33 and the FL brake hydraulic pressure adjusting part 34 of the normally open linear solenoid valve PC1 are connected from the first port side of the master cylinder MC of the normally open linear solenoid valve PC1. A check valve CV5 is arranged in parallel to allow only one-way flow of brake fluid to the side. A check valve CV6 similar to the check valve CV5 is arranged in parallel with the normally open linear solenoid valve PC2.

With the configuration described above, the brake control unit 30 is composed of two hydraulic circuits, one related to the two front wheels FR and FL and the other related to the two rear wheels RR and RL. The brake control unit 30 can supply brake fluid pressure (that is, MC fluid pressure Pm) corresponding to the amount of operation of the brake pedal BP to the wheel cylinders W** when all the solenoid valves are in the non-excited state. In addition, "**" attached to the end of various variables etc. is attached to the end of the same various variables etc. to indicate to which wheel FR etc. the same various variables etc. relate. , “fr” and so on.

On the other hand, in this state, by driving the motor MT to operate the hydraulic pumps HP1 and HP2, and by controlling the normally open linear solenoid valves PC1 and PC2, the pressure increasing valve PU** and the pressure reducing valve PD**, , WC hydraulic pressure Pw** can be adjusted independently.

That is, the brake control unit 30 can independently adjust the braking force applied to each wheel regardless of the operation of the brake pedal BP by the driver. As described above, the brake control unit 30 executes each control such as known DAC (Downhill Assist Control), ABS control, TRC (TRaction Control), etc., according to instructions from the control device 40 composed of the brake ECU 12, the engine ECU 13, and the like. can.

The DAC will now be described with reference to FIG. FIG. 3 is a schematic diagram showing how the vehicle 100 travels downhill. When the vehicle 100 travels downhill, if normal braking control is performed, the wheels may slip or lock. Therefore, the DAC controls the brake pressure so as to avoid the wheels from slipping or locking, and maintains the vehicle speed at a low speed. This allows the driver to concentrate on the steering operation with peace of mind.

Further, the TRC controls the brake pressure when the vehicle starts or accelerates to prevent the wheels from slipping.

However, in the prior art, if brake control such as DAC, ABS control, and TRC is continuously executed, the motor for operating the pump heats up due to continuous driving, and it becomes necessary to stop functions such as brake control for system protection. There was a case where it was lost.

Therefore, a technique for suppressing continuous driving of the motor for operating the pump in the braking control state of the vehicle 100 will be described below. This makes it possible to lengthen the continuous execution time of DAC, ABS control, TRC, and the like.

Returning to FIG. 1, the brake ECU 12 controls all wheel cylinders W in a braking control state in which the braking force of each wheel is controlled in accordance with the running state. Determine whether or not the pressure is not increased. When the brake ECU 12 determines that all wheels are in a non-increasing state, the brake ECU 12 stops the motor MT, stops the hydraulic pumps HP1 and HP2, and opens the normally open linear solenoid valves PC1 and PC2 (first pressure regulating valves). The valve is closed, and motor pumping suppression control is executed so that the pressure generated by the brake fluid pressure generator 32 (pressurizing means) is lower than the predetermined pressure generated in the reservoirs RS1 and RS2. Note that the reservoirs RS1 and RS2 have a mechanism (for example, a press mechanism using a return spring) that presses the movable portion with a predetermined pressure in a direction to decrease the volume of the reservoir chamber that stores the brake fluid. Reservoirs RS1 and RS2 are so-called pressure regulating reservoirs provided with ball valves and the like. When the ball valve descends and contacts the pedestal, the valve is closed. When the hydraulic pump HP1 is in a stopped state, the ball valve of the reservoir RS1 is opened when the pressure in the first connecting passage connected to the reservoir RS1 becomes equal to or less than a predetermined pressure that presses the movable portion in the direction of decreasing the volume of the reservoir chamber. is opened, and when the pressure in the first connecting passage exceeds a predetermined pressure that presses the movable portion in the direction of decreasing the volume of the reservoir chamber, the ball valve of the reservoir RS1 is closed. Similarly, when the hydraulic pump HP2 is in a stopped state, if the pressure in the second connection flow path connected to the reservoir RS2 falls below a predetermined pressure that presses the movable portion in the direction of decreasing the volume of the reservoir chamber, the reservoir RS2 The ball valve of RS2 is opened, and the ball valve of reservoir RS2 is closed when the pressure in the second connecting passage exceeds a predetermined pressure that presses the movable portion in the direction of decreasing the volume of the reservoir chamber.

In addition, when all wheels are in a non-increased state, specifically, in the system of the front wheels, even if the pressure on the upstream side of the normally open linear solenoid valve PC1 decreases due to the closing of the normally open linear solenoid valve PC1, the normally open linear solenoid valve PC1 is closed. The required brake fluid pressure (for example, fluid pressure higher than the wheel cylinder pressure) is secured on the wheel cylinder side of the solenoid valve PC1, and the front wheels FL and FR are controlled by the pressure increase valve PU and the pressure decrease valve PD corresponding to each. It maintains and reduces the hydraulic pressure according to the instruction signal. In the rear wheel system, even if the pressure on the upstream side of the normally open linear solenoid valve PC1 decreases due to the closing of the normally open linear solenoid valve PC2, the brake fluid pressure necessary for the wheel cylinder side of the normally open linear solenoid valve PC1 is maintained. (for example, hydraulic pressure higher than the wheel cylinder pressure), and for the rear wheels RL and RR, by controlling the pressure increasing valve PU and the pressure reducing valve PD corresponding to each, the hydraulic pressure is maintained and reduced according to the instruction signal. conduct.

With this operation, when all wheels are in a non-increased state, even if the upstream pressurization (pressurization by the brake hydraulic pressure generator 32) is stopped, the hydraulic pressure of each wheel can be controlled to be maintained or reduced. At the same time, the pressure generated by the brake fluid pressure generating section 32 (pressurizing means) becomes smaller than the predetermined pressure generated in the reservoirs RS1 and RS2, so that even if the motor MT is not driven, the reservoirs RS1 and RS2 are filled with pressure. The brake fluid can be discharged to the upstream portion of the first pressure regulating valve, which is closer to the master cylinder MC than the first pressure regulating valve. In this embodiment, the brake fluid accumulated in the reservoir RS1 is discharged through the first connecting passage to the upstream portion of the normally open linear solenoid valve PC1 to which the first connecting passage is connected, and the brake fluid accumulated in the reservoir RS2 is discharged. The liquid is discharged through the second connecting passage to the upstream portion of the normally open linear electromagnetic valve PC2 to which the second connecting passage is connected.

Further, when the brake ECU 12 determines that all wheels are not in the non-increasing state, the brake fluid pressure generator 32 generates a predetermined brake fluid pressure.

Next, referring to FIG. 4, the flow of control in the comparative example (conventional technology) and the first embodiment will be described. FIG. 4 is a sequence diagram showing the flow of control in the comparative example and the first embodiment. Here, as an example, a case of executing ABS control during DAC will be described.

The following points are common to the comparative example and the first embodiment. First, the rear wheels RR and RL are synchronized to increase, hold, and reduce pressure. Also, the change in hydraulic pressure over time at each wheel is the same. That is, the hydraulic pressure of the rear wheels RR and RL repeats increase and decrease three times, and the hydraulic pressure of the front wheels FR and FL repeats increase and decrease more times.

In the comparative example, upstream pressurization is always ON. Also, the rear wheel differential pressure valve (normally open linear solenoid valve PC2) and the front wheel differential pressure valve (normally open linear solenoid valve PC1) are normally OFF (open). Therefore, the amount of brake fluid stored in the reservoir, that is, the amount of fluid in the reservoir (in FIG. 4, the sum of the amount of fluid in the reservoirs RS1 and RS2 is schematically shown), the pumps (hydraulic pumps HP1 and HP2) It does not decrease except when is ON. Therefore, when the reservoir fluid amount exceeds a certain level, it is necessary to operate the pump to pump out the brake fluid. The amount of brake fluid flowing into and out of the reservoir is calculated, for example, based on the control information for brake control, such as the wheel cylinder pressure during decompression, the decompression time, and the discharge amount of the pump. It can be obtained by using a method of estimating by using a stroke sensor, a method of detecting by providing a stroke sensor or the like in the reservoir, or the like.

On the other hand, in the first embodiment, upstream pressurization is turned off during times t1 to t2, t3 to t4, t5 to t6, t7 to t8, t9 to t10, and t11 to t12, which are time zones in which all wheels are not pressurized. , the rear wheel differential pressure valve (normally open linear solenoid valve PC2) and the front wheel differential pressure valve (normally open linear solenoid valve PC1) are turned ON (closed). Therefore, during those time periods, the pressure in the upstream portion of the first pressure regulating valve is lower than the predetermined pressure in the reservoirs RS1 and RS2, so that the motor MT is not driven (that is, the pump (hydraulic pump HP1 , HP2) are OFF), the brake fluid accumulated in the reservoirs RS1 and RS2 can be automatically discharged to the upstream portion of the first pressure regulating valve.

Next, processing by the brake ECU 12 of the first embodiment will be described with reference to FIG. FIG. 5 is a flowchart showing processing by the brake ECU 12 of the first embodiment.

First, in step S1, the brake ECU 12 determines whether or not the braking control state is established. If Yes, the process proceeds to step S2, and if No, the process returns to step S1.

In step S2, the brake ECU 12 determines whether or not all wheels are in a non-increase state. If Yes, the process proceeds to step S3, and if No, the process proceeds to step S4.

In step S3, the brake ECU 12 executes motor pumping suppression control. Specifically, the brake ECU 12 stops upstream pressurization and turns on (closes) the rear wheel differential pressure valve (normally open linear solenoid valve PC2) and the front wheel differential pressure valve (normally open linear solenoid valve PC1). As a result, the brake fluid accumulated in the reservoirs RS1 and RS2 is automatically discharged to the upstream portion of the first pressure regulating valve without driving the motor MT. After step S3, the process proceeds to step S4.

In step S4, the brake ECU 12 determines whether or not the braking control state is established. If Yes, the process returns to step S2, and if No, the process ends. After the motor pumping suppression control is started in step S3, if the result in step S2 is No, the motor pumping suppression control is stopped.

As described above, according to the first embodiment, it is possible to suppress the continuous driving of the motor for operating the pump in the braking control state of the vehicle. That is, in the braking control state, when all wheels are in a non-increasing state, the upstream pressurization is stopped, and the rear wheel differential pressure valve (normally open linear solenoid valve PC2) and the front wheel differential pressure valve (normally open linear solenoid valve PC1) are turned ON. (closed), it is possible to control the maintenance and pressure reduction of the hydraulic pressure of each wheel, and the brake fluid accumulated in the reservoirs RS1 and RS2 can be released to the first pressure regulating valve without driving the motor MT. Can be automatically discharged upstream.

Therefore, it is possible to reduce the possibility of stopping functions such as braking control due to overheating of the motor MT. In addition, the load on the brake hydraulic pressure generator 32 can be reduced by not continuing the upstream pressurization.

Note that the brake control unit 30 may synchronize the operation of increasing, maintaining, and reducing the pressure by the hydraulic pressure adjusting unit for at least two wheels among the wheels. By doing so, the time period during which all wheels are in the non-increase state increases, which is more effective.

(Second embodiment)
Next, a second embodiment will be described. Descriptions of items that are the same as in the first embodiment will be omitted as appropriate. In the second embodiment, when the brake ECU 12 determines that the amount of brake fluid stored in the reservoir (at least one of the reservoirs RS1 and RS2) is equal to or greater than a predetermined amount (for example, 80% of the full tank), the brake ECU 12 performs motor pumping suppression control. Do not execute, drive motor MT.

FIG. 6 is a flowchart showing processing by the brake ECU of the second embodiment. First, in step S1, the brake ECU 12 determines whether or not it is in a braking control state. If Yes, the process proceeds to step S11, and if No, the process returns to step S1.

In step S11, the brake ECU 12 determines whether or not the reservoir fluid amount is equal to or greater than a predetermined amount. If Yes, the process proceeds to step S12, and if No, the process proceeds to step S2. Hereinafter, as an example, the case of Yes in step S11 means that the amount of brake fluid in the reservoir RS1 is equal to or greater than a predetermined amount. However, the present invention is not limited to this, and the same applies when the amount of brake fluid in the reservoir RS2 exceeds a predetermined amount.

In step S12, the brake ECU 12 drives the motor MT. As a result, the pump (hydraulic pump HP1) is activated, and the brake fluid in the reservoir RS1 is reduced. After step S12, the process proceeds to step S4.

In step S2, the brake ECU 12 determines whether or not all wheels are in a non-increase state. If Yes, the process proceeds to step S3, and if No, the process proceeds to step S4.

In step S3, the brake ECU 12 executes motor pumping suppression control, and proceeds to step S4.

In step S4, the brake ECU 12 determines whether or not it is in a braking control state. If Yes, the process returns to step S11, and if No, the process ends.

As described above, according to the second embodiment, when the amount of brake fluid stored in at least one of the reservoirs RS1 and RS2 is equal to or greater than a predetermined amount (for example, 80% of a full tank), all wheels are in a non-increase state. Even so, the motor pumping suppression control is not executed (if it is being executed, it is stopped), and the motor MT is driven. As a result, the amount of brake fluid in the corresponding reservoir can be quickly reduced, and the possibility of the reservoir becoming full can be further reduced.

(Third embodiment)
Next, a third embodiment will be described. Descriptions of items that are the same as in the first embodiment will be omitted as appropriate. FIG. 7 is a diagram showing a schematic configuration of the brake control section 30 of the third embodiment. In the third embodiment, the brake control unit 30 includes a normally closed electromagnetic opening/closing valve 38 (introduction valve) that opens and closes the first connection flow path. In addition, a normally closed electromagnetic opening/closing valve 39 (introduction valve) that performs opening/closing operation is provided in the second connection flow path. Also, the reservoir RS1 and the reservoir RS2 in FIG. 7 are normal reservoirs, unlike the reservoir RS1 and the reservoir RS2 in FIG. Then, the brake ECU 12 opens the normally closed electromagnetic on-off valve 38 and the normally closed electromagnetic on-off valve 39 during execution of the motor pumping suppression control.

Thus, according to the third embodiment, the motor pumping suppression control can be realized even in the brake control unit 30 of the type shown in FIG.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

For example, in the above-described embodiment, the case of executing ABS control during DAC has been described, but the present invention is not limited to this. The present invention may be applied when executing TRC.

When stopping the upstream pressurization, instead of turning off the upstream pressurization, the upstream pressurization may generate a hydraulic pressure weaker than a predetermined pressure generated by return springs or the like in the reservoirs RS1 and RS2.

Further, in Embodiments 1 to 3, the brake hydraulic pressure generating section 32 uses a piston to perform upstream pressurization, but it may be performed by a method other than the piston.

DESCRIPTION OF SYMBOLS 12... Brake ECU, 13... Engine ECU, 20... Engine, 30... Brake control part, 40... Control apparatus, 100... Vehicle.

Claims (5)

A wheel cylinder provided in each wheel of the vehicle for generating a braking force by brake fluid pressure, a pressurizing means provided in a flow path connected to the wheel cylinder, and between the pressurizing means and the wheel cylinder. A braking control device for controlling a braking device comprising a hydraulic pressure adjusting means provided,
In the braking device,
The hydraulic pressure adjusting means has a first pressure adjusting valve, a second pressure adjusting valve, a reservoir, a pump, and a motor,
The first pressure regulating valve is provided in a flow path connecting the wheel cylinder and the pressurizing means,
The second pressure regulating valve is provided in a flow path connecting the wheel cylinder and the reservoir,
The reservoir is arranged at a position where it is connected to the wheel cylinder via the second pressure regulating valve and is connected to the pressurizing means and the first pressure regulating valve via a connecting passage, and has a mechanism that presses the movable part with a predetermined pressure in the direction of decreasing the volume of the reservoir chamber that stores the
the pump pumps up the brake fluid in the reservoir and discharges it to a predetermined position in a flow path connecting the pressurizing means and the wheel cylinder;
the motor operates the pump;
The braking control device is
In the braking control state for controlling the braking force of each wheel according to the running state, it is determined whether or not the brake hydraulic pressure of all the wheel cylinders is in a state of either holding or decreasing, i.e., an all-wheel non-increase state. When it is determined that all wheels are in a non-increasing state, the motor is stopped, the first pressure regulating valve is closed, and the pressure generated by the pressurizing means is generated in the reservoir. A braking control device comprising a control section that executes motor pumping suppression control to reduce the pressure to a pressure lower than the predetermined pressure. 2. The braking control device according to claim 1, wherein said control unit causes said pressurizing means to generate a predetermined brake hydraulic pressure when determining that said all-wheel non-increase state is not in effect. The braking device is provided with an introduction valve in the connection flow path, the connection flow path is opened when the introduction valve is open, and the connection flow path is blocked when the introduction valve is closed,
3. The braking control device according to claim 1, wherein said control unit opens said introduction valve during execution of said motor pumping suppression control. 4. The control unit according to any one of claims 1 to 3, wherein, when determining that the amount of brake fluid stored in the reservoir is equal to or greater than a predetermined amount, the control unit drives the motor without executing the motor pumping suppression control. Braking control device according to paragraph. 5. The braking device according to any one of claims 1 to 4, wherein the braking device synchronizes pressure increasing, holding, and decreasing operations by the hydraulic pressure adjusting means for at least two or more of the wheels. braking control device.

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