JP2016002977A - Brake system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake system capable of controlling a master cylinder pressure for controlling both a driver operation and vehicle behaviors.SOLUTION: A brake system of the present invention comprises: an upstream brake fluid pressure generator boosting a brake operation force of a brake operation member operated by a driver and generating a master cylinder fluid pressure; and a downstream brake fluid pressure generator driving a pump and a control valve and capable of controlling a wheel cylinder fluid pressure to be increased or reduced. The brake system calculates a driver-intended fluid pressure in response to an operation state of the brake operation member, calculates a demanded wheel cylinder fluid pressure in response to a state of an own vehicle and/or wheels, and calculates a demanded master cylinder fluid pressure on the basis of at least the calculated driver-intended fluid pressure and the calculated demanded wheel cylinder fluid pressure.

Description

  The present invention relates to a brake control device that applies a braking force to a vehicle.

  Conventionally, a technique described in Patent Document 1 is known as a brake device. This publication includes a hydraulic control booster that controls the master cylinder pressure and a hydraulic control actuator that controls the wheel cylinder pressure.

JP 2007-38764 A

However, in the configuration as disclosed in Patent Document 1, there is room for examination on how to generate a master cylinder pressure that achieves both a driver operation and a vehicle behavior control when controlling the master cylinder pressure. It remained.
An object of this invention is to provide the brake device which can control the master cylinder pressure which aimed at coexistence with driver operation and control regarding vehicle behavior.

  In order to achieve the above object, in the brake device of the present invention, an upstream brake hydraulic pressure generating device that boosts the brake operating force of a brake operating member operated by a driver to generate a master cylinder hydraulic pressure, a pump, and a control valve A downstream brake fluid pressure generator that can control the increase or decrease of the wheel cylinder fluid pressure, and calculates the driver target fluid pressure according to the operation state of the brake operation member, and the state of the host vehicle or / and the wheel Accordingly, the required wheel cylinder hydraulic pressure is calculated, and the required master cylinder hydraulic pressure is calculated based on at least the calculated driver target hydraulic pressure and the calculated required foil cylinder hydraulic pressure.

  Therefore, it is possible to calculate the required master cylinder hydraulic pressure that is compatible with the driver's operation and the state of the vehicle, and a brake device with good controllability can be obtained.

It is a figure which shows schematic structure of the brake device of Example 1 with a hydraulic circuit. It is a hydraulic-pressure circuit diagram of a downstream brake fluid pressure generator. FIG. 3 is a control block diagram illustrating a brake fluid pressure control process according to the first embodiment. 3 is a flowchart illustrating a calculation process of a wheel cylinder hydraulic pressure and a master cylinder hydraulic pressure according to the first embodiment. It is a time chart in the case of performing control according to a driver's brake pedal operation, without performing control, such as VDC, ABS, TCS, and BAS, in the brake device of Example 1. It is a time chart showing wheel cylinder fluid pressure control and master cylinder fluid pressure control when performing ABS in the brake device of Example 1. It is the schematic explaining the predetermined value setting method added to the request | requirement master cylinder hydraulic pressure in ABS of Example 1. FIG. It is a time chart showing wheel cylinder fluid pressure control and master cylinder fluid pressure control when performing VDC in the brake device of Example 1. It is a time chart showing wheel cylinder fluid pressure control and master cylinder fluid pressure control in case ABS is performed when VDC is performed in the brake device of Example 1. It is a time chart showing wheel cylinder fluid pressure control and master cylinder fluid pressure control in case brake control of Example 1 performs TCS. 3 is a time chart showing a hydraulic pressure state of a wheel cylinder W / C of each wheel in VDC of the first embodiment. It is a time chart showing wheel cylinder fluid pressure control and master cylinder fluid pressure control in case BAS is performed in the brake equipment of Example 1. 6 is a flowchart illustrating a calculation process of wheel cylinder hydraulic pressure and master cylinder hydraulic pressure according to the second embodiment. It is a time chart showing wheel cylinder fluid pressure control and master cylinder fluid pressure control in case ABS is performed when VDC is performed in the brake device of Example 2.

[Example 1]
FIG. 1 is a diagram illustrating a schematic configuration of a brake device according to a first embodiment together with a hydraulic circuit. Although the brake device according to the first embodiment is applied to a rear wheel drive vehicle, the brake device may be applied to a front wheel drive vehicle or a four wheel drive vehicle without particular limitation. The brake devices are wheel cylinders W / C (FL), W / C (FR), W / C (RL), W / C (RR) (hereinafter collectively referred to as “wheel cylinders”) provided on each wheel FL to RR of the vehicle. A brake fluid as a working fluid is supplied to the wheel cylinder W / C to generate a brake fluid pressure (wheel cylinder fluid pressure), thereby applying a hydraulic braking force to each of the wheels FL to RR. The brake operation unit including the wheel cylinder W / C is a so-called disc type, and is provided with a brake disc that rotates integrally with a tire and a caliper (hydraulic brake caliper) including a brake pad. The brake device has two systems (primary P system and secondary S system) of brake pipes 107 and 108, and employs, for example, an X pipe type. In addition, you may employ | adopt other piping formats, such as front and rear piping. In the following, when distinguishing between members provided corresponding to the P system and members corresponding to the S system, the suffixes P and S are added to the end of each symbol.

  The brake device includes an upstream brake fluid pressure generating device 100 that can control the master cylinder fluid pressure, and a downstream brake fluid pressure generating device 105 that can control the wheel cylinder fluid pressure of each wheel. The upstream brake fluid pressure generating device 100 includes a brake pedal BP as a brake operation member that receives an input of a brake operation of a driver (driver), and a brake fluid pressure according to an operation amount (pedal stroke) of the brake pedal BP by the driver. Of the master cylinder 102 that generates (master cylinder pressure), the electric booster 103 that can control the piston pressure in the master cylinder by the motor or electromagnetic force regardless of the pedal stroke, and the electric cylinder booster 103. And an upstream controller 104 for controlling the state. The master cylinder 102 is a tandem type and has a master cylinder piston connected to a push rod 30 that moves in the axial direction in accordance with a driver's brake pedal operation. The push rod 30 is provided with a stroke sensor 90 that detects a pedal stroke.

  The electric booster 103 is capable of controlling the pressing force of the master cylinder piston by electromagnetic force in accordance with a command from the upstream controller 104. For example, the master cylinder piston is controlled by a ball screw mechanism that converts the rotational torque of the motor into axial torque. Is applied with a desired pressing force. Note that when the master cylinder piston is pressed by the push rod 30, both operate together, but when the electric booster 103 generates a pressing force when the push rod 30 is in the non-operating state, the master cylinder piston Only a pressing force can be applied. The upstream controller 104 includes a driver target hydraulic pressure calculation unit 104a that calculates a driver target hydraulic pressure based on the driver's brake pedal BP operation. Further, master cylinder hydraulic pressure control is performed by boost control for assisting the driver's brake pedal depression force and cooperative control with the downstream brake hydraulic pressure generator 105 described later. The upstream controller 104 creates a master cylinder hydraulic pressure that is higher than the master cylinder hydraulic pressure generated only by the driver's brake pedal depression force when the driver operates the brake pedal. Performs boost control to generate pressure braking force.

  The downstream brake fluid pressure generator 105 is provided between the wheel cylinder W / C and the master cylinder 102. The downstream brake fluid pressure generator 105 is individually connected to each wheel cylinder W / C via pipes 24, 25, 26, and 27, and the master cylinder fluid pressure or control fluid pressure is supplied to each wheel cylinder W / C. And can be supplied individually. The downstream brake fluid pressure generator 105 has a downstream controller 50. The downstream controller 50 receives as input signals a wheel speed sensor 51 that detects the wheel speed of each wheel and an integrated sensor 52 that can detect the longitudinal acceleration, lateral acceleration, and yaw rate of the vehicle. The upstream controller 104 and the downstream controller 50 are connected to each other via a CAN communication line CAN so that information can be transmitted and received between them. The downstream controller 50 includes a receiving unit 50c that receives the driver target hydraulic pressure calculated by the driver target hydraulic pressure calculating unit 104a of the upstream controller 104. The downstream controller 50 includes a required wheel cylinder hydraulic pressure calculation unit 50a that calculates a required wheel cylinder hydraulic pressure of each wheel based on an input signal of each sensor, and various electromagnetic waves that will be described later based on the calculated required foil cylinder hydraulic pressure. And a control unit 50b that outputs a control signal to a valve and a pump driving motor. Further, the downstream controller 50 includes a request master cylinder hydraulic pressure calculation unit 50d that calculates a request master cylinder hydraulic pressure based on the received driver target hydraulic pressure and the wheel cylinder hydraulic pressure calculated by various controls, and the request master cylinder 50d. And a transmitter 50e that transmits the cylinder hydraulic pressure to the upstream controller 104.

  The downstream controller 50 controls each actuator in the downstream brake fluid pressure generator 105 based on a built-in program. Detailed actions during control will be described later. Specific controls include anti-lock brake control (hereinafter referred to as ABS) for suppressing wheel slip due to braking, traction control brake control (hereinafter referred to as TCS) for suppressing drive wheel slip due to driving, Brake control for vehicle motion control (vehicle behavior stabilization control such as skidding prevention; hereinafter referred to as VDC), when any obstacle is detected in front of the vehicle, or when the driver's brake pedal sudden operation is detected Regardless of the brake pedal operation state of the driver, the brake assist control (hereinafter referred to as BAS) that generates a large braking force by driving the pump unit P to generate brake fluid pressure and pressurizing the wheel cylinder W / C, etc. Realize.

[Configuration of brake hydraulic circuit]
FIG. 2 is a hydraulic circuit diagram of the downstream brake hydraulic pressure generator 105. The hydraulic circuit is formed in a downstream brake hydraulic pressure generator 105 provided between the master cylinder 102 and the wheel cylinder W / C. This downstream brake fluid pressure generator 105 has a piping structure called X piping, which is composed of two systems, a P system brake fluid pressure circuit 21P and an S system brake fluid pressure circuit 21S. The left front wheel cylinder W / C (FL) and the right rear wheel wheel cylinder W / C (RR) are connected to the P system, and the right front wheel wheel cylinder W / C (FR) is connected to the S system. ), Wheel cylinder W / C (RL) for the left rear wheel is connected. The pump unit P is a tandem gear pump in which a gear pump PP and a gear pump PS are provided in each of the P system and the S system. The pump unit P may be a plunger pump.

  The brake pipes 107 and 108 connected to the master cylinder M / C and the downstream brake fluid pressure generator 105 are connected to the fluid passages 18P and 18S. The liquid path 18 and the suction side of the pump unit P are connected by liquid paths 10P and 10S. A master cylinder hydraulic pressure sensor 22 is provided on the liquid path 18P and between the brake pipe 107 and the connection portion of the liquid path 10P. The discharge side of the pump unit P and each wheel cylinder W / C are connected by liquid paths 11P and 11S. On each liquid passage 11, pressure increasing valves 3FL, 3RR, 3FR, 3RL, which are normally open solenoid valves corresponding to the respective wheel cylinders W / C, are provided. Further, check valves 6P and 6S are provided on each liquid passage 11 and between each pressure increasing valve 3 and the pump unit P. Each check valve 6 allows the flow of brake fluid pressure in the direction from the pump unit P toward the pressure increasing valve 3, and prohibits the flow in the opposite direction.

  Furthermore, each fluid passage 11 is provided with fluid passages 16FL, 16RR, 16FR, 16RL that bypass each pressure increasing valve 3, and the fluid passage 16 is provided with check valves 9FL, 9RR, 9FR, 9RL. Yes. Each check valve 9 allows the flow of brake hydraulic pressure in the direction from the wheel cylinder W / C toward the pump unit P, and prohibits the flow in the opposite direction. The master cylinder M / C and the liquid path 11 are connected by liquid paths 12P and 12S, and the liquid path 11 and the liquid path 12 merge between the pump unit P and the pressure increasing valve 3. On each liquid passage 12, gate-out valves 2P and 2S (hereinafter, gate-out valve 2), which are normally open solenoid valves, are provided. Each liquid path 12 is provided with liquid paths 17P and 17S that bypass each gate-out valve 2, and the liquid path 17 is provided with check valves 8P and 8S. Each check valve 8 allows the flow of brake fluid pressure in the direction from the master cylinder M / C side toward the wheel cylinder W / C, and prohibits the flow in the opposite direction.

  On the suction side of the pump unit P, reservoirs 15P and 15S are provided. The reservoir 15 includes check valves 7P and 7S that can block the flow of brake fluid from the fluid passage 10 into the reservoir 15. The check valve 7 is configured to be openable by raising a reservoir piston 15a provided in the reservoir 15. The check valve 7 is closed when the brake fluid pressure in the reservoir 15 is equal to or higher than a predetermined value (for example, 0.2 MPa) set in advance, and the check valve 7 is opened when the brake fluid pressure is less than the predetermined value. The reservoir 15 and the pump unit P are connected by liquid passages 14P and 14S. The wheel cylinder W / C and the liquid path 14 are connected by liquid paths 13P and 13S. The liquid path 13 and the liquid path 14 merge between the check valve 7 and the reservoir 15. Each liquid passage 13 is provided with a pressure reducing valve 4FL, 4RR, 4FR, 4RL, which is a normally closed solenoid valve.

  When executing VDC or TCS, the upstream brake fluid pressure generating device 100 is used as a fluid pressure source, the pressure increasing valve 3 of the wheel that needs to be increased is opened, and the pressure reducing valve 4 is closed. Further, the pressure-increasing valve 3 and the pressure-reducing valve 4 of the wheel that do not require pressure increase are closed. When the pressure is reduced after the pressure has been increased, the pressure reducing valve 4 is opened and the brake fluid is sent to the reservoir 15. When executing ABS, the upstream brake fluid pressure generating device 100 is used as a fluid pressure source, the pressure increasing valve 3 of the wheel that needs to be depressurized is closed, the depressurizing valve 4 is opened, and the brake fluid is sent to the reservoir 15. In any control, the brake fluid stored in the reservoir 15 is pumped up by the pump unit P and is returned to the master cylinder 102 side. In general, when VDC or TCS is performed only by the downstream brake hydraulic pressure generator 105, the pump unit P is used as a hydraulic pressure source. In the first embodiment, the master cylinder hydraulic pressure controlled by the upstream brake hydraulic pressure generator 100 is used. Is different in that it is a hydraulic pressure source. When executing BAS, the pump unit P of the downstream brake hydraulic pressure generator 105 is used as the hydraulic pressure source, the gate-out valve 2 is controlled in the closing direction, and the pressure increasing valve 3 for the wheel that needs to be increased is used. Is opened and the pressure reducing valve 4 is closed.

  FIG. 3 is a control block diagram illustrating a brake fluid pressure control process according to the first embodiment. The downstream controller 50 includes a required foil cylinder hydraulic pressure calculation unit 50a that calculates a required foil cylinder hydraulic pressure. The required wheel cylinder hydraulic pressure calculation unit 50a includes a vehicle control unit 50a1 that calculates the required wheel cylinder hydraulic pressure for vehicle control required by VDC (corresponding to the second required wheel cylinder hydraulic pressure), and ABS and TCS. A wheel control unit 50a2 that calculates a required wheel cylinder hydraulic pressure for wheel control (corresponding to a first required wheel cylinder hydraulic pressure). The required wheel cylinder hydraulic pressure control unit 50a controls the various solenoid valves and the pump unit P based on the calculated required foil cylinder hydraulic pressure, and controls each foil cylinder hydraulic pressure to a desired value.

  Further, a requested master cylinder hydraulic pressure calculation unit that calculates a required master cylinder hydraulic pressure capable of supplying a predetermined brake hydraulic pressure to the downstream brake hydraulic pressure generator 105 without giving a sense of incongruity to the driver operation to the master cylinder 102. 50d. The required master cylinder hydraulic pressure calculation unit 50d includes a driver target hydraulic pressure calculated by a driver target hydraulic pressure calculation unit 104a in the upstream controller 104, a vehicle control required wheel cylinder hydraulic pressure, and a wheel control required foil cylinder. Based on the hydraulic pressure, the final required master cylinder hydraulic pressure is calculated. The request master cylinder hydraulic pressure calculation process will be described later. Then, the calculated requested master cylinder hydraulic pressure is transmitted to the upstream brake hydraulic pressure generating device 100, and a desired master cylinder hydraulic pressure is achieved by the control of the electric booster 103. The driver target hydraulic pressure calculation unit 104a calculated in the upstream controller 104 has a map in which the SP characteristic in which the master cylinder hydraulic pressure corresponding to the brake pedal stroke is set is set, and the brake pedal stroke is Based on this, a target driver hydraulic pressure is calculated.

  As described above, in the brake device of the first embodiment, the upstream brake fluid pressure generating device 100 that can be used as a fluid pressure source by controlling the fluid pressure of the master cylinder 102, and the pump unit P as the fluid pressure source. The configuration including the downstream brake fluid pressure generator 105 is adopted. Here, if the brake fluid path is separated between the upstream side and the downstream side as in the brake-by-wire unit, the upstream brake fluid pressure generating device 100 and the downstream brake fluid pressure generating device 105 are There is no particular problem even if they are controlled separately. However, in the configuration of the first embodiment, the hydraulic pressure generated in the master cylinder 102 is supplied to the downstream brake hydraulic pressure generator 105, while the downstream brake hydraulic pressure generator 105 generates the master pressure when generating the hydraulic pressure. Since the brake fluid is sucked from the cylinder 102, they are related to each other via the brake fluid. Therefore, if the upstream side and the downstream side are individually controlled, vibration and control hunting may occur in the master cylinder hydraulic pressure, and it is difficult to control appropriately. In particular, since the master cylinder hydraulic pressure directly affects the brake pedal BP operated by the driver, it is necessary to control the master cylinder hydraulic pressure in a state in which the driver does not feel uncomfortable. Therefore, in the first embodiment, a stable master cylinder is calculated by calculating the master cylinder hydraulic pressure that is not uncomfortable for the driver in consideration of both the brake pedal BP operation state of the driver and the control state of the wheel cylinder hydraulic pressure. It was decided to provide a brake device capable of generating hydraulic pressure.

FIG. 4 is a flowchart illustrating a calculation process of the wheel cylinder hydraulic pressure and the master cylinder hydraulic pressure according to the first embodiment.
In step S1, the driver target hydraulic pressure is calculated based on the operation state of the brake pedal BP of the driver.
In step S2, it is determined whether or not to execute VDC. If the VDC is to be executed, the process proceeds to step S3. Otherwise, the process proceeds to step S7.
In step S3, the required wheel cylinder hydraulic pressure for vehicle control is set to the VDC hydraulic pressure calculated from VDC.
In step S4, it is determined whether or not wheel control such as ABS or TCS is executed. If the wheel control is executed, the process proceeds to step S5. Otherwise, the process proceeds to step S6.
In step S5, the required wheel cylinder hydraulic pressure is set to the hydraulic pressure (ABS or TCS hydraulic pressure) calculated by the wheel control, and the process proceeds to step S10.
In step S6, the required wheel cylinder hydraulic pressure is set to the vehicle control required foil cylinder hydraulic pressure (VDC hydraulic pressure), and the process proceeds to step S10.

In step S7, it is determined whether or not wheel control such as ABS or TCS is to be executed. If wheel control is to be executed, the process proceeds to step S8. Otherwise, the process proceeds to step S9.
In step S8, the required wheel cylinder hydraulic pressure is set to the hydraulic pressure (ABS or TCS hydraulic pressure) calculated by wheel control, and the process proceeds to step S10.
In step S9, the required wheel cylinder hydraulic pressure is set to the driver target hydraulic pressure, and the process proceeds to step S11.
In step S10, the wheel cylinder hydraulic pressure of each wheel is controlled based on the set required wheel cylinder hydraulic pressure.

In step S11, it is determined whether or not to execute brake assist control (hereinafter referred to as BAS) that generates a braking force that exceeds the driver's required braking force. If BAS is executed, the process proceeds to step S12. Proceed to step S14.
In step S12, a value P1 obtained by adding a predetermined value to the select high value of the required wheel cylinder hydraulic pressure is calculated. The select high value represents the highest required wheel cylinder hydraulic pressure among the required foil cylinder hydraulic pressures calculated for each wheel. Details of setting the predetermined value will be described later.
In step S13, a select low value between P1 and the driver target hydraulic pressure is set as the required master cylinder hydraulic pressure.

In step S14, it is determined whether TCS is being executed. If TCS is being executed, the process proceeds to step S15. Otherwise, the process proceeds to step S16.
In step S15, the selected high value of the required wheel cylinder hydraulic pressure for TCS control is set as the required master cylinder hydraulic pressure.
In step S16, it is determined whether or not the selected high value of the vehicle control required wheel cylinder hydraulic pressure is higher than the driver target hydraulic pressure. If the selected high value is higher than the driver target hydraulic pressure, the process proceeds to step S17. .
In step S17, the selected high value of the required wheel cylinder for vehicle control is set as the required master cylinder hydraulic pressure.

Next, the operation based on the flowchart will be described for each scene.
(Normal brake fluid pressure control process)
FIG. 5 is a time chart when the control according to the driver's brake pedal operation is performed without performing control such as VDC, ABS, TCS, and BAS in the brake device of the first embodiment.
When the driver depresses the brake pedal BP at time t1, the driver target hydraulic pressure is set accordingly, and the required wheel cylinder hydraulic pressure of each wheel is set according to the driver target hydraulic pressure. When the driver target hydraulic pressure is calculated as the required wheel cylinder hydraulic pressure for each wheel, the wheel cylinder hydraulic pressure is set to the driver target hydraulic pressure, and the required master cylinder hydraulic pressure is also controlled to the driver target hydraulic pressure. . In this case, since the upstream brake fluid pressure generating device 100 and the downstream brake fluid pressure generating device 105 do not interfere with each other, a stable braking state can be obtained.

(Brake fluid pressure control process in ABS)
FIG. 6 is a time chart showing wheel cylinder hydraulic pressure control and master cylinder hydraulic pressure control when ABS is performed in the brake device of the first embodiment. Of the above flowchart, the processing is mainly executed in steps S12 and S13.
When the driver depresses the brake pedal BP at time t1, the driver target hydraulic pressure is set accordingly. However, ABS is started at time t2, and a value obtained by adding a predetermined value to the select high value of the required wheel cylinder hydraulic pressure of each wheel is set as the required master cylinder hydraulic pressure. Here, a method for setting the predetermined value will be described.

  FIG. 7 is a schematic diagram for explaining a predetermined value setting method for adding to the required master cylinder hydraulic pressure in the ABS of the first embodiment. First, when ABS is started, a predetermined max value is added to P1 set during ABS, and a max-side added value is set. Similarly, a predetermined min value smaller than the max value is added to P1, and the min-side added value is set. The max side addition value and the min side addition value constitute a predetermined width, and this predetermined width is used as a dead zone. If the required master cylinder hydraulic pressure set at the start of ABS is within the dead zone, the required master cylinder hydraulic pressure is set to a constant value that maintains the value at that time. In other words, when adding a predetermined value to P1, a predetermined value at which the required master cylinder hydraulic pressure is constant is set and added.

  Here, the max side added value is set to be smaller than the driver target hydraulic pressure. This is because if the driver target hydraulic pressure equals the required master cylinder hydraulic pressure, the driver target hydraulic pressure detects and vibrates the stroke vibration associated with the ABS, and the vibration is reflected in the required master cylinder hydraulic pressure. is there. Further, the predetermined width of the dead zone is set to be larger than the hydraulic pressure amplitude of P1 that is generated when the road surface μ in the ABS continues. This is because the vibration of P1 is not reflected in the required master cylinder hydraulic pressure. Further, the min side added value is set to a value larger than the value obtained by adding the error of the wheel cylinder hydraulic pressure to the undershoot width of the master cylinder hydraulic pressure. An error when the wheel cylinder hydraulic pressure is detected by the sensor corresponds to detection accuracy, and an error when the wheel cylinder hydraulic pressure is estimated corresponds to an estimation error. That is, when the required master cylinder hydraulic pressure matches the wheel cylinder hydraulic pressure, the foil cylinder hydraulic pressure does not increase any more.

  In the dead zone set based on the above conditions, when the required master cylinder hydraulic pressure is maintained at a constant value, for example, when the value matches the min-side addition value, the required master cylinder hydraulic pressure and min Select high value with side added value. Further, for example, when the value coincides with the added value on the max side, a select low value of the requested master cylinder hydraulic pressure and the added value on the max side is selected. In addition, when the min-side added value becomes larger than the driver target hydraulic pressure, the driver target hydraulic pressure is limited. As a result, even if the wheel cylinder hydraulic pressure vibrates, it is possible to set the required master cylinder hydraulic pressure that is more stable due to the dead zone.

(Brake fluid pressure control process in VDC)
FIG. 8 is a time chart showing wheel cylinder hydraulic pressure control and master cylinder hydraulic pressure control when VDC is performed in the brake device of the first embodiment. Of the flowchart, the processing mainly executed in steps S16 and S17 is shown.
At time t1, the driver does not operate the brake pedal BP, but if it is determined that the vehicle behavior deviates from the neutral steer state to the oversteer or the understeer, the VDC generates a yaw moment in each wheel. A required wheel cylinder hydraulic pressure for vehicle control is calculated. Then, the selected high value of the required wheel cylinder hydraulic pressure for vehicle control of each wheel is set as the required master cylinder hydraulic pressure. Thereby, VDC can be executed using the master cylinder 102 as a hydraulic pressure source without pumping up. At this time, the brake pedal BP is not operated, and the driver does not feel uncomfortable.

(Brake fluid pressure control process when ABS is activated during VDC operation)
FIG. 9 is a time chart showing wheel cylinder hydraulic pressure control and master cylinder hydraulic pressure control when ABS is executed when VDC is performed in the brake device of the first embodiment. This is a process mainly executed in steps S16 and S17 in the flowchart.
At time t1, the driver does not operate the brake pedal BP, but if it is determined that the vehicle behavior deviates from the neutral steer state to the oversteer or the understeer, the VDC generates a yaw moment in each wheel. A required wheel cylinder hydraulic pressure for vehicle control is calculated. At this time, since the road surface μ is low on the front left wheel and the rear left wheel, ABS is executed, and the pressure is reduced to the required wheel cylinder hydraulic pressure calculated by the wheel control.
At this time, since the required master cylinder hydraulic pressure is set to the select high value of the required wheel cylinder hydraulic pressure for vehicle control requested from the VDC side, in order to perform ABS control with the master cylinder hydraulic pressure secured, Responsiveness of pressure increase / decrease control in ABS can be secured. Further, the brake pedal BP is not operated, and the driver does not feel uncomfortable.

(Brake fluid pressure control processing during TCS operation)
FIG. 10 is a time chart showing wheel cylinder hydraulic pressure control and master cylinder hydraulic pressure control when TCS is executed in the brake device of the first embodiment. This is a process mainly executed in steps S16 and S17 in the above flowchart.
At time t1, the driver does not operate the brake pedal BP, but if it is determined that a drive wheel slip is caused by the drive torque acting on the drive wheel, the TCS suppresses the drive slip on the drive wheel. The required wheel cylinder hydraulic pressure for TCS control is calculated. Since the selected high value of the required wheel cylinder hydraulic pressure for TCS control of each wheel is set as the required master cylinder hydraulic pressure, TCS control can be performed with the master cylinder hydraulic pressure secured. It is possible to secure the responsiveness of the pressure increase / decrease control at. Further, the brake pedal BP is not operated, and the driver does not feel uncomfortable.

(Regarding non-intensifying wheel wheel cylinder W / C increasing / decreasing valve control)
Here, when generating the required wheel cylinder hydraulic pressure for vehicle control or the required wheel cylinder hydraulic pressure for TCS control in VDC, before generating the master cylinder hydraulic pressure for the wheels that do not generate the wheel cylinder hydraulic pressure. Alternatively, at the same time when the master cylinder hydraulic pressure is detected as a value other than zero, not only the pressure increasing valve 3 is closed but also the pressure reducing valve 4 is closed. Hereinafter, the reason for closing both the pressure increasing and reducing valves 3 and 4 will be described.

  In the first embodiment, as shown in FIG. 2, a configuration including a check valve 7 as the reservoir 15 is employed. As described above, the check valve 7 is configured to be openable by raising the reservoir piston 15a provided in the reservoir 15. The check valve 7 is closed when the brake fluid pressure in the reservoir 15 is equal to or higher than a predetermined value (for example, 0.2 MPa) set in advance, and the check valve 7 is opened when the brake fluid pressure is less than the predetermined value. Therefore, when the master cylinder hydraulic pressure is generated, the master cylinder hydraulic pressure always acts on the check valve 7. Therefore, if the brake fluid supplied to the wheel cylinder W / C of the driving wheel is caused to flow out from the pressure reducing valve 4, the reservoir 15 Even if the brake fluid flows into the tank, and then the brake fluid in the reservoir is pumped up by the pump unit P, if the pressure falls below 0.2 Mpa, the check valve 7 opens and the master cylinder hydraulic pressure flows into the reservoir 15. Become. That is, once the brake fluid is stored in the reservoir 15 and becomes 0.2 MPa or more, even if the pump unit P is operated, the inside of the reservoir 15 cannot be decompressed to 0.2 MPa or less. At this time, since the reservoir 15 is also communicated with the pressure reducing valve 4 of the driven wheel (front wheel) that does not require the supply of brake fluid, the brake fluid flows from the reservoir 15 into the wheel cylinder W / C of the driven wheel, There is a problem of generating unnecessary wheel cylinder hydraulic pressure.

  FIG. 11 is a time chart showing the hydraulic state of the wheel cylinder W / C of each wheel in the VDC of the first embodiment. FIG. 11A is a time chart when only the pressure increasing valve 3 of the non-intensifying wheel is closed, and FIG. 11B is a state where both the pressure increasing valve 3 and the pressure reducing valve 4 of the non-pressure increasing wheel are closed. It is a time chart in the case. As shown in FIG. 11 (a), the wheel cylinder W / C (FR) for the right front wheel and the wheel cylinder W / C (RR) for the right rear wheel are non-pressure-increasing wheels. Only 3RR is closed and the pressure reducing valves 4FR and 4RR are opened. In this case, brake fluid flows from the reservoir 15 to the wheel cylinders W / C (FR) and W / C (RR) through the pressure reducing valves 4FR and 4RR, and it is difficult to secure control performance by generating unnecessary brake fluid pressure. is there. On the other hand, as shown in FIG. 11B, the wheel cylinders W / C (FR), which are non-pressure-increasing wheels, are closed by closing both the pressure increasing valves 3FR, 3RR and the pressure reducing valves 4FR, 4RR. ), Brake fluid inflow to W / C (RR) is prohibited, ensuring control performance.

(Brake fluid pressure control process in BAS)
FIG. 12 is a time chart showing wheel cylinder hydraulic pressure control and master cylinder hydraulic pressure control when BAS is executed in the brake device of the first embodiment. This is a process mainly executed in steps S12 and S13 in the above flowchart.
At time t1, the driver operates the brake pedal BP, and the required master cylinder hydraulic pressure gradually increases as the driver target hydraulic pressure increases. After that, at time t2, when any obstacle or the like is detected in front of the vehicle or a sudden operation of the brake pedal of the driver is detected, when the BAS associated with the sudden braking request is executed, the pump unit P is activated, The required foil cylinder hydraulic pressure increases. At this time, a driver target hydraulic pressure that is a select low value of the required master cylinder hydraulic pressure P1 and the driver target hydraulic pressure is set as the required master cylinder hydraulic pressure. That is, the brake fluid is sucked from the master cylinder 102 by the operation of the pump unit P, and the brake fluid stored in the reservoir 15 is returned to the master cylinder 102, whereby the brake fluid in the master cylinder 102 changes. However, since the master cylinder hydraulic pressure is controlled to the driver target hydraulic pressure, for example, the assist force of the electric booster 103 is appropriately controlled, and fluctuations in the master cylinder hydraulic pressure are suppressed. Therefore, it is possible to stably control the master cylinder hydraulic pressure, and to suppress a sense of discomfort to the driver.

[Effect of Example 1]
Hereinafter, effects of the brake device described in the first embodiment will be listed.
(1-1) a brake pedal BP (brake operation member) operated by the driver;
An upstream brake hydraulic pressure generator 100 capable of boosting the wheel cylinder W / C by boosting the brake operating force of the brake pedal BP to generate a master cylinder hydraulic pressure;
It has a pump unit P (pump) capable of returning the brake fluid sucked and discharged from the master cylinder 102 to the master cylinder 102 and a control valve, and drives the pump unit P and the control valve to control the wheel cylinder hydraulic pressure. Downstream brake fluid pressure generator 105 capable of increasing and decreasing pressure control,
A driver target hydraulic pressure calculation unit 104a that calculates a driver target hydraulic pressure according to the operation state of the brake pedal BP;
A required foil cylinder hydraulic pressure calculation unit 50a for calculating a required foil cylinder hydraulic pressure according to the state of the host vehicle or / and the wheel;
A brake device comprising: a required master cylinder hydraulic pressure calculation unit 50d that calculates a required master cylinder hydraulic pressure based on at least the calculated driver target hydraulic pressure and the calculated required foil cylinder hydraulic pressure.
Therefore, it is possible to calculate the required master cylinder hydraulic pressure that is compatible with the driver's operation and the state of the vehicle, and a brake device with good controllability can be obtained.

(2-2) In the brake device described in (1-1) above,
The required master cylinder hydraulic pressure calculation unit 50d calculates the required master cylinder hydraulic pressure based on the magnitude relationship between the driver target hydraulic pressure and the required wheel cylinder hydraulic pressure.
Therefore, it is possible to calculate the required master cylinder hydraulic pressure that is compatible with the driver's operation and the state of the vehicle, and a brake device with good controllability can be obtained.
(3-3) In the brake device described in (2-2) above,
The required foil cylinder hydraulic pressure calculation unit 50a calculates the required foil cylinder hydraulic pressure of each wheel,
The required master cylinder hydraulic pressure calculation unit 50d selects the required master cylinder hydraulic pressure when the calculated high required wheel cylinder hydraulic pressure of each wheel is smaller than the driver target hydraulic pressure. A brake device characterized in that a required master cylinder hydraulic pressure is calculated to be in a range not less than a hydraulic pressure and not more than a driver target hydraulic pressure.
Therefore, the required master cylinder hydraulic pressure can be controlled appropriately.
(4-4) In the brake device described in (3-3) above,
The required master cylinder hydraulic pressure calculation unit 50d calculates the required master cylinder hydraulic pressure based on a hydraulic pressure obtained by adding a predetermined value to the calculated required foil cylinder hydraulic pressure.
Therefore, the required master cylinder hydraulic pressure can be controlled to an appropriate value.
(5-5) In the brake device described in (4-4) above,
The predetermined value is a variable value that absorbs the vibration of the required wheel cylinder hydraulic pressure within a predetermined range and makes the required master cylinder hydraulic pressure a constant value larger than the required foil cylinder hydraulic pressure. .
Therefore, the required master cylinder hydraulic pressure can be controlled to an appropriate value.
(6-6) In the brake device described in (5-5) above,
A brake device, wherein when the required wheel cylinder hydraulic pressure changes and falls outside a predetermined range, the required master cylinder hydraulic pressure is changed to be within a predetermined range.
Therefore, the required master cylinder hydraulic pressure can be controlled to an appropriate value.

(7-7) In the brake device described in (3-3) above,
The downstream brake fluid pressure generator 105 includes ABS, TCS (wheel control unit) and VDC (vehicle control unit),
The required wheel cylinder hydraulic pressure calculation unit 50a includes a wheel control required wheel cylinder hydraulic pressure (first required wheel cylinder hydraulic pressure for the wheel control unit) and a vehicle control required wheel cylinder hydraulic pressure (vehicle control) for each wheel. 2nd required foil cylinder hydraulic pressure)
Select high demand foil cylinder hydraulic pressure for each calculated demand foil cylinder hydraulic pressure,
The requested master cylinder hydraulic pressure calculation unit 50d selects the calculated vehicle control required wheel cylinder hydraulic pressure, and if the selected high required wheel cylinder hydraulic pressure is equal to or higher than the calculated driver target hydraulic pressure, the vehicle control required wheel cylinder hydraulic pressure Select the required high pressure wheel cylinder hydraulic pressure as the required master cylinder hydraulic pressure, and if the calculated required wheel cylinder hydraulic pressure for wheel control falls below the calculated driver target hydraulic pressure, the required wheel cylinder for wheel control A brake device characterized in that the required master cylinder hydraulic pressure is calculated so that the hydraulic pressure is in a range not less than the required high pressure wheel cylinder hydraulic pressure and not higher than the driver target hydraulic pressure.
Therefore, the required master cylinder hydraulic pressure can be controlled to an appropriate value.
(8-8) In the brake device described in (7-7) above,
BAS (brake assist control unit) that pressurizes the wheel cylinder hydraulic pressure using the pump unit P of the downstream brake hydraulic pressure control device during the operation of the brake pedal BP by the driver,
The required foil cylinder hydraulic pressure calculation unit 50a calculates the required foil cylinder hydraulic pressure of each wheel,
The required master cylinder hydraulic pressure calculation unit 50d selects the calculated required wheel cylinder hydraulic pressure. If the required wheel cylinder hydraulic pressure is equal to or higher than the driver target hydraulic pressure, but the BAS is operating, the driver target hydraulic pressure is calculated. Is calculated as a required master cylinder hydraulic pressure.
Therefore, the required master cylinder hydraulic pressure can be controlled to an appropriate value.

(9-11) In the brake device described in (2-2) above,
The required foil cylinder hydraulic pressure calculation unit 50a calculates the required foil cylinder hydraulic pressure of each wheel,
When the calculated driver target hydraulic pressure is zero and the required foil cylinder hydraulic pressure is calculated, the master cylinder hydraulic pressure based on the required master cylinder hydraulic pressure is generated for the wheel with the required foil cylinder hydraulic pressure zero. A brake device characterized in that the brake fluid is prevented from flowing into the wheel cylinder W / C corresponding to the wheel before or after the required master cylinder hydraulic pressure becomes non-zero.
Therefore, the hydraulic pressure can be maintained at 0 in the non-control wheel.
(10-12) In the brake device described in (8-8) above,
The downstream brake fluid pressure generator 105 includes a pressure increasing valve 3 (first control valve) between the master cylinder 102 and the wheel cylinder W / C of each wheel, and brake fluid that flows out of the wheel cylinder W / C. Is provided with a pressure reducing valve 4 (second control valve) on each wheel between the reservoir 15 and the wheel cylinder W / C of each wheel,
By closing the pressure increasing valve 3, the brake fluid is prevented from flowing from the master cylinder 102 to the wheel cylinder W / C corresponding to the wheel, and by closing the pressure reducing valve 4, the wheel stored in the reservoir 15 is prevented. The brake device is characterized in that it prevents the brake fluid from flowing into the wheel cylinder W / C.
Therefore, the hydraulic pressure can be maintained at 0 in the non-control wheel.

(11-13) In the brake device described in (1-1) above,
The upstream brake fluid pressure generating device 100 includes a driver target fluid pressure calculation unit 104a that calculates a driver target fluid pressure according to the stroke of the brake pedal BP.
The downstream brake hydraulic pressure generator 105 includes a required wheel cylinder hydraulic pressure calculation unit 50a that calculates a required wheel cylinder hydraulic pressure, a receiving unit 50c that receives a driver target hydraulic pressure, and a driver target that has received the required wheel cylinder hydraulic pressure. A request master cylinder hydraulic pressure calculation unit 50d that calculates a required master cylinder hydraulic pressure from the hydraulic pressure, and a transmission unit 50e that transmits the calculated request master cylinder hydraulic pressure to the upstream brake hydraulic pressure generator 100,
The upstream brake fluid pressure generating device 100 drives the actuator to generate the received requested master cylinder fluid pressure.
Therefore, controllability can be improved by adopting a system configuration in which the requested master cylinder hydraulic pressure controlled by the upstream brake hydraulic pressure generator 100 is instructed by the downstream brake hydraulic pressure generator 105.

(12-14) Brake pedal BP operated by the driver;
A driver target hydraulic pressure calculation unit 104a that calculates a driver target hydraulic pressure according to the operation state of the brake pedal BP;
A required foil cylinder hydraulic pressure calculation unit 50a for calculating a required foil cylinder hydraulic pressure according to the behavior of the host vehicle or / and the wheel;
Electric booster 103 (control booster) that can pressurize the wheel cylinder W / C by generating the master cylinder hydraulic pressure according to the operation state of the brake pedal BP,
It has a pump unit P (pump) capable of returning the brake fluid sucked and discharged from the master cylinder 102 to the master cylinder 102 and a control valve, and drives the pump unit P and the control valve to control the wheel cylinder hydraulic pressure. Downstream brake hydraulic pressure generator 105 (hydraulic pressure unit) capable of increasing, maintaining and reducing pressure,
A required master cylinder hydraulic pressure calculation unit 50d for calculating a required master cylinder hydraulic pressure to be generated in the master cylinder 102 based on the magnitude relationship between the calculated driver target hydraulic pressure and the calculated required wheel cylinder hydraulic pressure; Brake device characterized.
Therefore, the required master cylinder hydraulic pressure can be controlled appropriately.

(13-15) In the brake device described in (12-14) above,
The required foil cylinder hydraulic pressure calculation unit 50a calculates the required foil cylinder hydraulic pressure of each wheel,
The requested master cylinder hydraulic pressure calculation unit 50d selects the requested master cylinder hydraulic pressure equal to or higher than the selected high requested wheel cylinder hydraulic pressure when the calculated required foil cylinder hydraulic pressure is lower than the driver target hydraulic pressure. A brake device characterized by calculating a demand master cylinder fluid pressure so that it may become the range below a driver target fluid pressure.
Therefore, the required master cylinder hydraulic pressure can be controlled to an appropriate value.
(14-16) In the brake device described in (12-14) above,
The required master cylinder hydraulic pressure calculation unit 50d calculates the required master cylinder hydraulic pressure as a hydraulic pressure obtained by adding a predetermined value to the calculated required foil cylinder hydraulic pressure.
Therefore, the required master cylinder hydraulic pressure can be controlled to an appropriate value.
(15-17) In the brake device described in (13-15) above,
BAS (brake assist control) that pressurizes the wheel cylinder hydraulic pressure using the pump unit P of the downstream brake hydraulic pressure generator 105 during the operation of the brake operating member by the driver,
The required foil cylinder hydraulic pressure calculation unit 50a calculates the required foil cylinder hydraulic pressure of each wheel,
The required master cylinder hydraulic pressure calculation unit 50d selects the calculated required wheel cylinder hydraulic pressure. If the required wheel cylinder hydraulic pressure is equal to or higher than the driver target hydraulic pressure, but the BAS is operating, the driver target hydraulic pressure is calculated. Is calculated so as to be the required master cylinder hydraulic pressure.
Therefore, the required master cylinder hydraulic pressure can be controlled to an appropriate value.

(16-19) a brake pedal BP (brake operation member) operated by the driver;
A driver target hydraulic pressure calculation unit 104a that calculates a driver target hydraulic pressure according to the operation state of the brake pedal BP;
A required foil cylinder hydraulic pressure calculation unit 50a for calculating a required foil cylinder hydraulic pressure in accordance with the behavior of the host vehicle or the wheel;
An electric booster 103 (electric booster) capable of generating a master cylinder hydraulic pressure according to the operation state of the brake pedal BP and pressurizing the wheel cylinder W / C;
An upstream controller 104 (a booster controller) that controls the electric booster 103 and includes a driver target hydraulic pressure calculation unit 104a;
It has a pump unit P (pump) and a control valve that can return the brake fluid sucked and discharged from the master cylinder 102 to the master cylinder 102. The pump unit P and the control valve are driven to increase the wheel cylinder hydraulic pressure. Downstream brake fluid pressure generator 105 (hydraulic pressure unit) capable of holding and decompression control,
A downstream controller 50 (hydraulic unit controller) that controls the downstream brake fluid pressure generator 105 and has a required wheel cylinder fluid pressure calculation;
CAN communication line (communication line) connecting both controllers 104 and 50,
With
The downstream controller 50 receives the calculated driver target hydraulic pressure via the CAN communication line, and causes the master cylinder 102 to generate based on the magnitude relationship between the received driver target hydraulic pressure and the calculated required wheel cylinder hydraulic pressure. A required master cylinder hydraulic pressure calculation unit 50d for calculating the required master cylinder hydraulic pressure,
The calculated requested master cylinder hydraulic pressure is transmitted to the upstream controller 104 via the CAN communication line, and the upstream controller 104 controls the electric booster 103 based on the transmitted requested master cylinder hydraulic pressure. Brake device.
Therefore, since the upstream brake fluid pressure generating device 100 is controlled based on a command from the downstream controller 50, the controllability can be improved.

(17-20) In the brake device described in (16-19) above,
The required foil cylinder hydraulic pressure calculation unit 50a calculates the required foil cylinder hydraulic pressure of each wheel,
The required master cylinder hydraulic pressure calculation unit 50d calculates the required master cylinder hydraulic pressure when the calculated required high wheel cylinder hydraulic pressure is smaller than the driver target hydraulic pressure. A brake device that calculates a hydraulic pressure obtained by adding a predetermined value to the hydraulic pressure.
Therefore, the required master cylinder hydraulic pressure can be controlled to an appropriate value.

[Example 2]
Next, Example 2 will be described. Since the basic configuration is the same as that of the first embodiment, only different points will be described. FIG. 13 is a flowchart illustrating a calculation process of the wheel cylinder hydraulic pressure and the master cylinder hydraulic pressure according to the second embodiment. Since steps S1 to S13 are the same as those in the first embodiment, the other steps will be described.
In step S116, it is determined whether or not the selected high value of the required wheel cylinder hydraulic pressure is higher than the driver target hydraulic pressure. If it is higher, the process proceeds to step S117, and if it is lower than the driver target hydraulic pressure, the process proceeds to step S12.
In step S117, the selected high value of the required wheel cylinder is set as the required master cylinder hydraulic pressure.
The required wheel cylinder hydraulic pressure is a value set in any of steps S5, S6, S8 and S9. When VDC is being executed, the required wheel cylinder hydraulic pressure for vehicle control is the required foil cylinder hydraulic pressure, and when ABS or TCS is being executed, the required wheel cylinder hydraulic pressure for wheel control is the required foil cylinder hydraulic pressure. If no control is performed, the driver target hydraulic pressure is set to the required wheel cylinder hydraulic pressure.

  That is, in Example 1, when the VDC is executed when the driver does not operate the brake pedal BP, even if ABS intervenes in the middle of the VDC, the vehicle control request wheel cylinder hydraulic pressure select high value is requested. It was set as the master cylinder hydraulic pressure. On the other hand, in Example 2, since the select high value of the required wheel cylinder hydraulic pressure is set as the required master cylinder hydraulic pressure, when ABS intervenes in the middle of VDC, the select high of the required wheel cylinder hydraulic pressure for wheel control is selected. The difference is that the value is set as the required master cylinder hydraulic pressure.

(Brake fluid pressure control process when ABS is activated during VDC operation)
FIG. 14 is a time chart showing wheel cylinder hydraulic pressure control and master cylinder hydraulic pressure control when ABS is executed when VDC is performed in the brake device of the second embodiment. This is a process mainly executed in steps S116 and S117 in the flowchart.
At time t1, the driver does not operate the brake pedal BP, but if it is determined that the vehicle behavior deviates from the neutral steer state to the oversteer or the understeer, the VDC generates a yaw moment in each wheel. A required wheel cylinder hydraulic pressure for vehicle control is calculated. At this time, since the road surface μ is low on the front left wheel and the rear left wheel, ABS is executed, and the pressure is reduced to the required wheel cylinder hydraulic pressure calculated by the wheel control.
At this time, the required master cylinder hydraulic pressure is set to the select high value of the required wheel cylinder hydraulic pressure for wheel control requested from the ABS side, so the master cylinder hydraulic pressure secures the hydraulic pressure necessary to perform ABS. The ABS control is performed in the state. Further, the brake pedal BP is not operated, and the driver does not feel uncomfortable.

  Basically, the ABS intervenes during the execution of the VDC is a scene in which the wheel cylinder hydraulic pressure applied by the VDC is too high with respect to the frictional force of the road surface, thereby causing a tendency to lock the wheel. Therefore, if the required master cylinder hydraulic pressure that can ensure the foil cylinder hydraulic pressure required for VDC is secured, the foil cylinder hydraulic pressure can be secured even for the pressure increase / decrease control accompanying the execution of ABS. However, when the required wheel cylinder hydraulic pressure of VDC is set as the required master cylinder hydraulic pressure, it is necessary to close the pressure increasing valve 3 and open the pressure reducing valve 4 because it is necessary to depressurize the wheel on which the ABS operates. Basically, when executing VDC, the pressure increasing valve 3 of 2 or 3 wheels is closed and the pressure is increased only to the wheel cylinder W / C of the desired wheel, so this increasing pressure wheel starts ABS. Then, since the pressure increasing valves 3 are also closed, the scenes in which all the pressure increasing valves 3 are closed increase. When all the pressure boosting valves 3 are closed, all the flow paths through which the brake fluid flows from the master cylinder 102 are blocked, so the electric booster 103 has a very low compressibility, in other words, a rigid body with extremely high hydraulic rigidity is controlled. And shall be.

  For example, consider the case where the electric booster 103 is configured to apply a desired pressing force to the master cylinder piston by a ball screw mechanism that converts the rotational torque of the motor into axial torque. In this case, since the change amount of the master cylinder hydraulic pressure with respect to the change amount of the master cylinder piston position is very large, extremely delicate position control is required. However, since the ball screw mechanism has a large friction and a large variation in friction, it is extremely difficult to execute a delicate position control. Therefore, if the master cylinder hydraulic pressure is controlled to the required wheel cylinder hydraulic pressure for vehicle control with all the pressure increasing valves 3 closed, the master cylinder hydraulic pressure is likely to vibrate, ensuring the controllability of ABS. May be difficult.

  On the other hand, in the second embodiment, when ABS intervenes during VDC, the required master cylinder hydraulic pressure is also set to the select high value of the required wheel cylinder hydraulic pressure for wheel control requested by ABS. The pressure increasing valve 3 can be kept open in the wheel. As a result, since the hydraulic rigidity of the control target of the electric booster 103 can be kept low, the master cylinder hydraulic pressure can be avoided from being vibrated and stable master cylinder hydraulic pressure control can be realized.

As described above, the following operational effects are obtained in the second embodiment.
(18-9) In the brake device described in (3-3) above,
The downstream brake fluid pressure generator 105 includes ABS, TCS (wheel control unit), and VDC (vehicle control unit).
The required wheel cylinder hydraulic pressure calculation unit 50a includes a wheel control required wheel cylinder hydraulic pressure (first required wheel cylinder hydraulic pressure for the wheel control unit) and a vehicle control required wheel cylinder hydraulic pressure (vehicle control) for each wheel. 2nd required foil cylinder hydraulic pressure)
Select high demand foil cylinder hydraulic pressure for each calculated demand foil cylinder hydraulic pressure,
The requested master cylinder hydraulic pressure calculation unit 50d selects the calculated wheel control hydraulic pressure for wheel control when the required high wheel cylinder hydraulic pressure is equal to or higher than the calculated driver target hydraulic pressure. Select the required high pressure wheel cylinder hydraulic pressure as the required master cylinder hydraulic pressure, and if the calculated required wheel cylinder hydraulic pressure for wheel control falls below the calculated driver target hydraulic pressure, the required wheel cylinder for wheel control A brake device characterized in that the required master cylinder hydraulic pressure is calculated so that the hydraulic pressure is in a range not less than the required high pressure wheel cylinder hydraulic pressure and not higher than the driver target hydraulic pressure.
Therefore, the hydraulic rigidity of the downstream brake hydraulic pressure generator 105 can be prevented from becoming excessively high, and the required master cylinder hydraulic pressure can be stably generated.

(19-10) In the brake device described in (18-9) above,
BAS (brake assist controller) that pressurizes the wheel cylinder hydraulic pressure using the pump unit P (pump) of the downstream brake hydraulic pressure generator 105 during the operation of the brake pedal BP (brake operating member) by the driver,
The required foil cylinder hydraulic pressure calculation unit 50a calculates the required foil cylinder hydraulic pressure of each wheel,
The required master cylinder hydraulic pressure calculation unit 50d selects the calculated required wheel cylinder hydraulic pressure. If the required wheel cylinder hydraulic pressure is equal to or higher than the driver target hydraulic pressure, but the BAS is operating, the driver target hydraulic pressure is calculated. Is calculated so as to be the required master cylinder hydraulic pressure.
Therefore, the required master cylinder hydraulic pressure can be controlled to an appropriate value.
(20-17) In the brake device described in (13-15) above,
The downstream brake fluid pressure generator 105 includes ABS, TCS (wheel control unit), and VDC (vehicle control unit).
The required wheel cylinder hydraulic pressure calculation unit 50a includes a wheel control required master cylinder hydraulic pressure (first required wheel cylinder hydraulic pressure for the wheel control unit) and a vehicle control required wheel cylinder hydraulic pressure (vehicle control) for each wheel. 2nd required foil cylinder hydraulic pressure)
Select high demand foil cylinder hydraulic pressure for each calculated demand foil cylinder hydraulic pressure,
The requested master cylinder hydraulic pressure calculation unit 50d selects the calculated wheel control hydraulic pressure for wheel control when the required high wheel cylinder hydraulic pressure is equal to or higher than the calculated driver target hydraulic pressure. Select the required high pressure wheel cylinder hydraulic pressure as the required master cylinder hydraulic pressure, and if the calculated required wheel cylinder hydraulic pressure for wheel control falls below the calculated driver target hydraulic pressure, the required wheel cylinder for wheel control A brake device characterized in that the required master cylinder hydraulic pressure is calculated so that the hydraulic pressure is in a range not less than the required high pressure wheel cylinder hydraulic pressure and not higher than the driver target hydraulic pressure.
Therefore, the required master cylinder hydraulic pressure can be controlled to an appropriate value.
(21-18) In the brake device described in (20-17) above,
The downstream brake fluid pressure generator 105 includes a wheel control unit and a vehicle control unit,
The required wheel cylinder hydraulic pressure calculation unit 50a calculates a wheel control required wheel cylinder hydraulic pressure and a vehicle control required wheel cylinder hydraulic pressure in each wheel,
Select high demand foil cylinder hydraulic pressure for each calculated demand foil cylinder hydraulic pressure,
The requested master cylinder hydraulic pressure calculation unit 50d selects the calculated wheel control hydraulic pressure for wheel control when the required high wheel cylinder hydraulic pressure is equal to or higher than the calculated driver target hydraulic pressure. Select high pressure wheel cylinder hydraulic pressure as the required master cylinder hydraulic pressure, and if the calculated vehicle control required wheel cylinder hydraulic pressure falls below the calculated driver target hydraulic pressure, the vehicle control required wheel cylinder A brake device characterized in that the required master cylinder hydraulic pressure is calculated so that the hydraulic pressure is in a range not less than the required high pressure wheel cylinder hydraulic pressure and not higher than the driver target hydraulic pressure.
Therefore, the required master cylinder hydraulic pressure can be controlled to an appropriate value.

  The present invention has been described based on the embodiments. However, the present invention is not limited to the above embodiments, and other configurations may be adopted. In the first embodiment, the reservoir 15 having the check valve 7 is used. However, a reservoir without the check valve is used, and a normally closed gate-in valve is provided between the master cylinder and the reservoir 12. A valve-type hydraulic circuit may be employed. In this case, since the reservoir maintains the atmospheric release pressure, unnecessary wheel cylinder hydraulic pressure is not generated even if the pressure reducing valve 4 of the wheel that does not require pressure increase is closed by VDC or TCS.

  As the electric booster, the configuration including the ball screw mechanism is shown in the first embodiment, but the assist may be provided not only by the ball screw mechanism but also by a configuration in which the motor is provided with a pinion and the master cylinder piston is provided with a rack. Moreover, it is good also as a structure which controls a master cylinder piston by electromagnetic attraction force.

  In addition, an example has been shown in which the upstream controller 104 and the downstream controller 50 are connected via a CAN communication line. Also good.

2 Gate-out valve
3 Booster valve
4 Pressure reducing valve
7 Check valve
15 Reservoir
50 Downstream controller
50a Required wheel cylinder hydraulic pressure calculator
50a1 Vehicle control unit
50a2 Wheel control unit
50b control unit
50c receiver
50c receiver
50d Required master cylinder hydraulic pressure calculator
50e transmitter
100 Upstream brake fluid pressure generator
102 Master cylinder
103 electric booster
104 Upstream controller
104a Driver target hydraulic pressure calculator
105 Downstream brake fluid pressure generator
BP brake pedal
CAN communication line
M / C master cylinder
P Pump unit
W / C wheel cylinder

Claims (15)

A brake operating member operated by the driver;
An upstream brake fluid pressure generating device capable of boosting a wheel cylinder by boosting a brake operation force of the brake operation member to generate a master cylinder fluid pressure;
A pump and a control valve capable of returning the brake fluid sucked and discharged from the master cylinder to the master cylinder and a control valve, and controlling the pressure increase / decrease of the wheel cylinder hydraulic pressure by driving the pump and the control valve. A downstream brake fluid pressure generator capable of
A driver target hydraulic pressure calculation unit that calculates a driver target hydraulic pressure according to an operation state of the brake operation member;
A required wheel cylinder hydraulic pressure calculating unit that calculates the required wheel cylinder hydraulic pressure according to the state of the host vehicle or / and the wheel;
A brake device comprising: a required master cylinder hydraulic pressure calculation unit that calculates a required master cylinder hydraulic pressure based on at least the calculated driver target hydraulic pressure and the calculated required foil cylinder hydraulic pressure. The brake device according to claim 1, wherein
The required master cylinder hydraulic pressure calculating unit calculates a required master cylinder hydraulic pressure based on a magnitude relationship between the driver target hydraulic pressure and the required wheel cylinder hydraulic pressure. The brake device according to claim 2,
The required foil cylinder hydraulic pressure calculation unit calculates the required foil cylinder hydraulic pressure of each wheel,
The required master cylinder hydraulic pressure calculating unit selects the required master cylinder hydraulic pressure when the calculated high required wheel cylinder hydraulic pressure is smaller than the driver target hydraulic pressure. The brake device, wherein the required master cylinder hydraulic pressure is calculated to be in a range not less than a high required foil cylinder hydraulic pressure and not more than the driver target hydraulic pressure. The brake device according to claim 3,
The required master cylinder hydraulic pressure calculation unit calculates the required master cylinder hydraulic pressure based on a hydraulic pressure obtained by adding a predetermined value to the calculated required foil cylinder hydraulic pressure. The brake device according to claim 4,
The predetermined value is a variable value that absorbs vibration of the required foil cylinder hydraulic pressure within a predetermined range and makes the required master cylinder hydraulic pressure a constant value larger than the required foil cylinder hydraulic pressure. And brake device. The brake device according to claim 5,
When the required wheel cylinder hydraulic pressure changes and falls outside the range of the predetermined width, the required master cylinder hydraulic pressure is changed to be within the range of the predetermined width. The brake device according to claim 3,
The downstream brake fluid pressure generator includes a wheel control unit and a vehicle control unit,
The required wheel cylinder hydraulic pressure calculation unit calculates a first required wheel cylinder hydraulic pressure for the wheel control unit and a second required foil cylinder hydraulic pressure for the vehicle control unit in each wheel,
Calculate the selected high demand wheel cylinder hydraulic pressure of each calculated demand wheel hydraulic pressure,
The request master cylinder hydraulic pressure calculation unit selects the second request wheel cylinder hydraulic pressure calculated when the high request wheel cylinder hydraulic pressure is equal to or higher than the calculated driver target hydraulic pressure. Wheel wheel hydraulic pressure select high required wheel cylinder hydraulic pressure is calculated as the required master cylinder hydraulic pressure, and when the calculated first required wheel cylinder hydraulic pressure is less than or equal to the calculated driver target hydraulic pressure, The brake device, wherein the required master cylinder hydraulic pressure is calculated to be in a range not less than the high-selection required foil cylinder hydraulic pressure and not more than the driver target hydraulic pressure of the first required master cylinder hydraulic pressure. The brake device according to claim 7,
A brake assist control unit that pressurizes the wheel cylinder hydraulic pressure using a pump of the downstream brake hydraulic pressure control device during operation of a brake operation member by a driver;
The required foil cylinder hydraulic pressure calculation unit calculates the required foil cylinder hydraulic pressure of each wheel,
The required master cylinder hydraulic pressure calculation unit selects the calculated required wheel cylinder hydraulic pressure, even when the brake assist control is operating even if the required high required wheel cylinder hydraulic pressure is equal to or higher than the driver target hydraulic pressure, A brake device that calculates a driver target hydraulic pressure as a required master cylinder hydraulic pressure. The brake device according to claim 3,
The downstream brake fluid pressure generator includes a wheel control unit and a vehicle control unit,
The required wheel cylinder hydraulic pressure calculation unit calculates a first required wheel cylinder hydraulic pressure for the wheel control unit and a second required foil cylinder hydraulic pressure for the vehicle control unit in each wheel,
Calculate the selected high demand wheel cylinder hydraulic pressure of each calculated demand wheel hydraulic pressure,
The request master cylinder hydraulic pressure calculation unit selects the first request foil cylinder hydraulic pressure when the selected high request wheel cylinder hydraulic pressure is equal to or higher than the calculated driver target hydraulic pressure. Wheel wheel hydraulic pressure select high required wheel cylinder hydraulic pressure is calculated as the required master cylinder hydraulic pressure, and when the calculated first required wheel cylinder hydraulic pressure is less than or equal to the calculated driver target hydraulic pressure, The brake device characterized in that the required master cylinder hydraulic pressure is calculated so that the first required master cylinder hydraulic pressure is in a range not less than the select high required wheel cylinder hydraulic pressure and not more than the driver target hydraulic pressure. The brake device according to claim 9,
A brake assist control unit that pressurizes the wheel cylinder hydraulic pressure using a pump of the downstream brake hydraulic pressure control device during operation of a brake operation member by a driver;
The required foil cylinder hydraulic pressure calculation unit calculates the required foil cylinder hydraulic pressure of each wheel,
The required master cylinder hydraulic pressure calculation unit selects the calculated required wheel cylinder hydraulic pressure, even when the brake assist control is operating even if the required high required wheel cylinder hydraulic pressure is equal to or higher than the driver target hydraulic pressure, A brake device, wherein the driver target hydraulic pressure is calculated to be a required master cylinder hydraulic pressure. The brake device according to claim 2,
The required foil cylinder hydraulic pressure calculation unit calculates the required foil cylinder hydraulic pressure of each wheel,
When the calculated driver target hydraulic pressure is zero and the required foil cylinder hydraulic pressure is calculated, a master cylinder fluid based on the required master cylinder hydraulic pressure is applied to a wheel having a zero required foil cylinder hydraulic pressure. A brake device that prevents the brake fluid from flowing into the wheel cylinder corresponding to the wheel before the pressure is generated or at the same time as the required master cylinder hydraulic pressure becomes non-zero. The brake device according to claim 8,
The downstream brake fluid pressure generating device includes a first control valve between the master cylinder and the wheel cylinder of each wheel, and includes a reservoir capable of temporarily storing brake fluid flowing out of the wheel cylinder. Each wheel has a second control valve between the reservoir and the wheel cylinder of each wheel,
By closing the first control valve, the brake fluid is prevented from flowing from the master cylinder to the wheel cylinder corresponding to the wheel, and is stored in the reservoir by closing the second control valve. A brake device that prevents a brake fluid from flowing into a wheel cylinder corresponding to the wheel. The brake device according to claim 1, wherein
The upstream brake fluid pressure generator includes the driver target fluid pressure calculation unit that calculates a driver target fluid pressure according to a stroke of the brake operation member,
The downstream brake fluid pressure generating device includes the requested wheel cylinder fluid pressure calculating unit that calculates the requested wheel cylinder fluid pressure, a receiving unit that receives the driver target fluid pressure, and the received wheel cylinder fluid pressure. The request master cylinder hydraulic pressure calculation unit that calculates the request master cylinder hydraulic pressure from a driver target hydraulic pressure, and a transmission unit that transmits the calculated request master cylinder hydraulic pressure to the upstream brake hydraulic pressure generator,
The upstream brake fluid pressure generating device drives the actuator to generate the received requested master cylinder fluid pressure. A brake operating member operated by the driver;
A driver target hydraulic pressure calculation unit that calculates a driver target hydraulic pressure according to an operation state of the brake operation member;
A required foil cylinder hydraulic pressure calculation unit for calculating a required foil cylinder hydraulic pressure according to the behavior of the host vehicle or / and the wheel;
A control booster capable of pressurizing the wheel cylinder by generating a master cylinder hydraulic pressure according to the operating state of the working member;
A pump and a control valve capable of returning the brake fluid sucked and discharged from the master cylinder to the master cylinder, and driving the pump and the control valve to increase the wheel cylinder hydraulic pressure; A hydraulic unit capable of holding and reducing pressure,
A required master cylinder hydraulic pressure calculating unit for calculating a required master cylinder hydraulic pressure to be generated in the master cylinder based on a magnitude relationship between the calculated driver target hydraulic pressure and the calculated required wheel cylinder hydraulic pressure; Brake device characterized by. A brake operating member operated by the driver;
A driver target hydraulic pressure calculation unit that calculates a driver target hydraulic pressure according to an operation state of the brake operation member;
A required foil cylinder hydraulic pressure calculation unit for calculating a required foil cylinder hydraulic pressure according to the behavior of the host vehicle or the wheel;
An electric booster capable of generating a master cylinder hydraulic pressure according to the operating state of the brake operating member to pressurize the wheel cylinder;
A booster controller that controls the electric booster and includes the driver target hydraulic pressure calculator;
A pump and a control valve capable of returning the brake fluid sucked and discharged into the master cylinder to the master cylinder and driving the pump and the control valve to increase, hold, and reduce pressure of the wheel cylinder hydraulic pressure A hydraulic unit capable of
A hydraulic unit controller that controls the hydraulic unit and includes the required foil cylinder hydraulic pressure calculation;
A communication line connecting the controllers;
With
The hydraulic unit controller receives the calculated driver target hydraulic pressure via the communication line, and based on a magnitude relationship between the received driver target hydraulic pressure and the calculated required wheel cylinder hydraulic pressure, A required master cylinder hydraulic pressure calculating section for calculating a required master cylinder hydraulic pressure to be generated in the cylinder;
The calculated requested master cylinder hydraulic pressure is transmitted to the booster controller via the communication line, and the booster controller controls the electric booster based on the transmitted requested master cylinder hydraulic pressure. apparatus.

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