WO2017170596A1 - Braking device for vehicle - Google Patents

Braking device for vehicle Download PDF

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Publication number
WO2017170596A1
WO2017170596A1 PCT/JP2017/012733 JP2017012733W WO2017170596A1 WO 2017170596 A1 WO2017170596 A1 WO 2017170596A1 JP 2017012733 W JP2017012733 W JP 2017012733W WO 2017170596 A1 WO2017170596 A1 WO 2017170596A1
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WO
WIPO (PCT)
Prior art keywords
hydraulic pressure
electronic control
control unit
precharge
reservoir
Prior art date
Application number
PCT/JP2017/012733
Other languages
French (fr)
Japanese (ja)
Inventor
康人 石田
達史 小林
山本　貴之
Original Assignee
株式会社アドヴィックス
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2016126462A external-priority patent/JP6623952B2/en
Application filed by 株式会社アドヴィックス filed Critical 株式会社アドヴィックス
Priority to DE112017001749.1T priority Critical patent/DE112017001749T5/en
Priority to CN201780020959.3A priority patent/CN109070853B/en
Priority to US16/086,891 priority patent/US11364890B2/en
Publication of WO2017170596A1 publication Critical patent/WO2017170596A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force

Definitions

  • the present invention relates to a vehicle braking device.
  • fading a phenomenon called fading is known in which the friction coefficient (the effectiveness of the brake) gradually decreases as the friction surface becomes hot during braking.
  • the wheel cylinder hydraulic pressure is increased by the hydraulic unit to suppress the decrease in deceleration due to fading, if the master cylinder piston bottoms (bottoming), the wheel cylinder hydraulic pressure can be increased further. It will disappear. To prevent bottoming even during fading, it is necessary to increase the size of the master cylinder.
  • Patent Document 1 describes that a check valve that allows the flow of brake fluid from the reservoir to the pressure chamber of the master cylinder is provided.
  • a check valve that allows the flow of brake fluid from the reservoir to the pressure chamber of the master cylinder is provided.
  • Patent Document 1 cannot avoid an increase in the number of parts, an increase in cost, and an increase in weight due to the addition of a check valve. Further, since the fade state is determined based on the master cylinder hydraulic pressure at the time of braking operation and the deceleration of the vehicle, the deceleration may be temporarily insufficient.
  • the present invention has been made to address the above-described problems, and an object of the present invention is to provide a vehicle braking device that improves the pressurization performance during fading without increasing the size of the master cylinder.
  • the vehicular braking apparatus includes a reservoir (RS) for storing brake fluid, a pressure chamber (13a, 13b), and the reservoir (RS) when an operation amount of a brake pedal (BP) exceeds a predetermined amount.
  • a master cylinder (MC) that generates a hydraulic pressure corresponding to an operation amount of the brake pedal (BP) by shutting off the communicating ports (12a, 12b), the master cylinder (MC), and a wheel cylinder (Wfr, Wfl, Wrr, Wrl), a hydraulic unit (HU) for adjusting the hydraulic pressure of the wheel cylinder (Wfr, Wfl, Wrr, Wrl), and an electronic control unit for controlling the hydraulic unit (HU) (ECU).
  • the vehicle braking device is characterized in that the electronic control unit (ECU) is connected to a wheel member (Wfr, Wfl, Wrr, Wrl) on a rotating member fixed to a wheel (FR, FL, RR, RL).
  • ECU electronice control unit
  • the port (12a) , 12b) sucks the brake fluid from the reservoir (RS) through the ports (12a, 12b) during a period in which the pressure chambers (13a, 13b) and the reservoir (RS) are communicated,
  • the hydraulic unit (HU) is configured to perform precharging to be supplied to the wheel cylinders (Wfr, Wfl, Wrr, Wrl).
  • the electronic control unit is configured to calculate a target value of the hydraulic pressure of the wheel cylinder (Wfr, Wfl, Wrr, Wrl) when the precharge is performed based on the temperature related value. May be.
  • the brake fluid consumption in the pressure chamber of the master cylinder can be reduced by sucking the brake fluid from the reservoir before the driver operates the brake pedal more than a predetermined amount in the fade state. it can. Therefore, the master cylinder can be prevented from being enlarged.
  • the required wheel cylinder hydraulic pressure varies depending on the degree of the fade state. Therefore, by applying the target value of the wheel cylinder hydraulic pressure at the time of executing the precharge based on the temperature related value, it is possible to improve the pressurization response during the fade according to the degree of the fade state.
  • the electronic control unit may be configured to adjust the target value to a larger value as the decrease speed of the accelerator pedal operation amount is larger or as the increase speed of the brake pedal operation amount is larger. Good.
  • the greater the rate of decrease in the accelerator pedal operation amount the higher the probability that a sudden braking operation will be performed thereafter.
  • the greater the increase rate of the brake pedal operation amount the more brake fluid should be supplied to the wheel cylinder by precharging. Therefore, by setting the target value of the wheel cylinder hydraulic pressure by precharging to be larger as the decrease rate of the accelerator pedal operation amount is larger or the increase rate of the brake pedal operation amount is larger, the brake pedal operation amount is more than a predetermined amount. Before it becomes, the brake fluid in the reservoir can be reliably and sufficiently supplied to the wheel cylinder, and as a result, pressurization response at the time of fading can be further enhanced.
  • the electronic control unit starts gradually decreasing the target value according to the operation mode of the driver of the vehicle at the time of executing the precharge, and ends the execution of the precharge when the target value becomes zero. It may be configured as follows. Since pre-charge supplies brake fluid to the wheel cylinder in advance before the driver operates the brake pedal more than a predetermined amount, the pre-charge may end when it can be determined from the driver's operation that no further pre-charge is necessary. desirable. Therefore, the continuation of unnecessary precharge is avoided by starting the gradual reduction of the target value of the wheel cylinder hydraulic pressure by precharging according to the operation mode of the driver and terminating the precharging when the target value becomes zero. be able to.
  • the electronic control unit is connected to the front wheel (FR, FL) system or the rear wheel (RR, RL) system only in the pre-train.
  • the hydraulic unit (HU) may be controlled to perform charging.
  • the pressurization response can be enhanced by applying pre-pressurization to only one of the two hydraulic circuits.
  • the liquid consumption of the rear wheel cylinder is smaller than that of the front wheels, so the master cylinder is configured to cover the liquid volume of the rear wheel system, and the front wheel system with higher liquid consumption is insufficient. If the amount of liquid is supplemented by precharging, the master cylinder can be made smaller.
  • the rear wheel brake is less likely to cause deceleration of the vehicle. Therefore, when precharge is executed only on the rear wheel system side, a natural brake feeling can be obtained.
  • FIG. 1 is a schematic configuration diagram of a vehicle braking device according to an embodiment of the present invention. It is a flowchart of the control which electronic control unit ECU shown in FIG. 1 performs. It is a time chart (the 1) explaining operation
  • FIG. 1 shows a schematic configuration of a vehicle braking apparatus according to an embodiment of the present invention.
  • “**” added to the end of various variables or the like is attached to the end of the various variables or the like to indicate whether the various variables or the like relates to the wheels FR, FL, RR, or RL.
  • Inclusive notation such as “fr” and “fl”.
  • Vehicle braking devices generate friction braking force by wheel cylinder hydraulic pressure on wheels **.
  • the braking device of the present embodiment generates a hydraulic pressure corresponding to the booster 11 that amplifies the operating force of the brake pedal BP and the operation amount (stroke or pedaling force) of the brake pedal BP.
  • a master cylinder MC a reservoir RS for storing brake fluid, a hydraulic unit HU capable of adjusting the hydraulic pressure of the wheel cylinder supplied to a wheel cylinder W ** disposed on the wheel **, and a hydraulic unit HU
  • an electronic control unit ECU to be controlled.
  • a friction member for example, a brake pad
  • a rotating member for example, a brake disc
  • the booster 11 for example, a negative pressure booster, a hydraulic pressure booster, an electric booster or the like can be adopted.
  • the master cylinder MC of the present embodiment is a tandem type master cylinder having two pressure chambers 13a and 13b defined by two pistons arranged in series in the cylinder body.
  • the reservoir RS and the pressure chambers 13a and 13b communicate with each other via the communication ports 12a and 12b.
  • a hydraulic pressure (master cylinder hydraulic pressure Pm) corresponding to the operation amount of the brake pedal BP is generated in the pressure chambers 13a and 13b.
  • the master cylinder MC outputs the master cylinder hydraulic pressure Pm from the two output ports 14a and 14b.
  • the hydraulic unit HU includes linear solenoid valves PC1 and PC2, brake fluid pressure adjusting units 33 to 36, and a reflux brake fluid supply unit 37.
  • a normally open linear solenoid valve PC1 is interposed between one output port 14a of the master cylinder MC and the upstream portion of the brake fluid pressure adjusting unit 33, 34, and the other output port 14b of the master cylinder MC and the brake fluid pressure adjustment.
  • a normally open linear solenoid valve PC2 is interposed between the upstream portions of the portions 35 and 36. Details of the linear solenoid valves PC1 and PC2 will be described later.
  • the brake fluid pressure adjusting units 33 to 36 include a pressure-increasing valve PU ** which is a 2-port 2-position switching type normally open electromagnetic on-off valve, and a pressure reducing valve PD ** which is a 2-port 2-position switching type normally closed electromagnetic on-off valve. It consists of and.
  • the pressure increasing valve PU ** can communicate / block the upstream portion of the corresponding adjusting portion of the brake fluid pressure adjusting portions 33 to 36 and the wheel cylinder W **.
  • the pressure reducing valve PD ** can communicate / block the wheel cylinder W ** and the corresponding one of the reservoirs RS1 and RS2.
  • the hydraulic pressure of the wheel cylinder W ** (wheel cylinder hydraulic pressure Pw **) can be increased, held and reduced by controlling the pressure increasing valve PU ** and the pressure reducing valve PD **. Yes.
  • the reflux brake fluid supply unit 37 includes a DC motor MT and two hydraulic pumps (gear pumps) HP1 and HP2 that are simultaneously driven by the motor MT.
  • the hydraulic pumps HP1 and HP2 pump up the brake fluid in the reservoirs RS1 and RS2 returned from the pressure reducing valve PD **, and supply the pumped brake fluid to upstream portions of the brake fluid pressure adjusting units 33 to 36, respectively. It is like that.
  • the hydraulic pumps HP1 and HP2 respectively suck and suck the brake fluid in the reservoir RS via the communication ports 12a and 12b.
  • the brake fluid is supplied to upstream portions of the brake fluid pressure adjusting units 33 to 36, respectively.
  • a force in an opening direction based on a biasing force from a coil spring (not shown) is constantly applied to the valve bodies of the normally open linear electromagnetic valves PC1 and PC2, and a corresponding adjusting unit among the brake fluid pressure adjusting units 33 to 36.
  • a closing force based on a suction force that increases proportionally according to Id) acts.
  • the command differential pressure ⁇ Pd which is the command value of the linear valve differential pressure ⁇ P
  • the normally open linear solenoid valves PC1 and PC2 are closed when ⁇ Pd is larger than ⁇ P, and are opened when ⁇ Pd is smaller than ⁇ P.
  • the brake fluid upstream of the corresponding adjusting unit among the brake hydraulic pressure adjusting units 33 to 36 corresponds to the corresponding electromagnetic among the normally open linear electromagnetic valves PC1 and PC2.
  • the linear valve differential pressure ⁇ P can be adjusted to coincide with the command differential pressure ⁇ Pd by flowing to the corresponding port side of the master cylinder MC via the valve.
  • the brake fluid that has flowed into the corresponding port side of the master cylinder MC is returned to the corresponding reservoir among the reservoirs RS1 and RS2.
  • the linear valve differential pressure ⁇ P can be controlled in accordance with the command current Id of the normally open linear electromagnetic valves PC1 and PC2. ing.
  • the pressure upstream of the brake fluid pressure adjusting units 33 to 36 is a value (Pm + ⁇ P) obtained by adding the linear valve differential pressure ⁇ P to the master cylinder fluid pressure Pm. Note that after the hydraulic pumps HP1 and HP2 are stopped in a state where the linear valve differential pressure ⁇ P is adjusted to a value larger than zero, the linear valve differential pressure is adjusted by adjusting the command current Id in the decreasing direction. ⁇ P can still be adjusted only in the decreasing direction.
  • the brake fluid is supplied to the master cylinder MC by a one-way valve connected in parallel with the normally open linear solenoid valves PC1 and PC2. Flows into the upstream portion of the brake fluid pressure adjusting section 33-36.
  • the braking device of the present embodiment includes two hydraulic circuits, a system related to the left and right front wheels FR and FL and a system related to the left and right rear wheels RR and RL.
  • the brake device adjusts the wheel cylinder hydraulic pressure Pw ** to a value equal to the master cylinder hydraulic pressure Pm when all the solenoid valves are in the non-excited state.
  • the wheel cylinder hydraulic pressure Pw ** is set to the hydraulic pressure (Pm + ⁇ P) by driving the motor MT (therefore, the hydraulic pumps HP1, HP2) and controlling the normally open linear solenoid valves PC1, PC2. Adjusted to Furthermore, the wheel cylinder hydraulic pressure Pw ** can be independently adjusted for each wheel by controlling the pressure increasing valve PU ** and the pressure reducing valve PD **. That is, regardless of the operation of the brake pedal BP by the driver, the braking force applied to the wheel ** can be adjusted independently for each wheel.
  • the electronic control unit ECU includes a CPU, a ROM, a RAM, an interface, and the like.
  • the interface is connected to various sensors / switches including a master cylinder hydraulic pressure sensor 44 that detects the master cylinder hydraulic pressure Pm, and supplies signals from the sensors / switches to the CPU, and in response to instructions from the CPU.
  • Drive signals are sent to the solenoid valves of the hydraulic unit HU (normally open linear solenoid valves PC1, PC2, pressure increasing valve PU **, and pressure reducing valve PD **) and the motor MT.
  • the electronic control unit ECU of the present embodiment includes a wheel speed sensor that detects the rotational speed of the wheel, a brake switch that selectively outputs a signal corresponding to whether or not the brake pedal BP is operated, and an operation amount of the brake pedal BP.
  • a signal from a stroke sensor that detects a pedal stroke, an accelerator opening sensor that detects an accelerator opening as an operation amount of an unillustrated accelerator pedal, a longitudinal acceleration sensor, a lateral acceleration sensor, a yaw rate sensor, and the like can be received.
  • signals from sensors / switches can be obtained from other devices via a communication bus.
  • the vehicle speed can be calculated based on the detection result of the wheel speed sensor.
  • the electronic control unit ECU determines whether or not the brake pad (the friction member of the present embodiment) is in a fade state in step S10, and if it is not in a fade state (step S10: NO), Return to step S10. That is, the electronic control unit ECU stands by in step S10 until it is determined that the brake pad is in a fade state.
  • step S10: YES the electronic control unit ECU calculates a precharge target hydraulic pressure in step S20.
  • FIG. 3 is a time chart for explaining the operation of the vehicle braking device according to the present embodiment.
  • the brake pad temperature (pad temperature) gradually increases due to repeated braking.
  • the electronic control unit ECU determines whether the brake pad is in a fade state based on the pad temperature. Specifically, when the pad temperature becomes equal to or higher than the threshold value th1, it is determined that the brake pad is in a fade state.
  • the pad temperature can be obtained by a sensor that measures the pad temperature.
  • the pad temperature varies depending on the brake pedal operation time, the number of brake pedal operations, and the amount of brake pedal operation, and the higher the temperature, the higher the pad temperature. Furthermore, the pad temperature fluctuates according to the vehicle speed (kinetic energy), and becomes higher as the kinetic energy converted into thermal energy by operating the brake pedal increases. Therefore, the electronic control unit ECU can determine whether or not the brake pad is in a fade state based on those temperature related values related to the pad temperature (or the estimated pad temperature value estimated therefrom).
  • the electronic control unit ECU determines that the brake pad is in a fade state
  • the electronic control unit ECU calculates a precharge target hydraulic pressure according to the pad temperature (measured value or estimated value). Specifically, as shown in FIG. 3, the electronic control unit ECU calculates the precharge target hydraulic pressure to be larger as the difference between the pad temperature and the threshold value th1 is larger at the timing of transition from acceleration to deceleration. Further, an upper limit value (for example, 0.5 MPa) can be set for the precharge target hydraulic pressure.
  • the electronic control unit ECU acquires the accelerator opening and the brake pedal stroke in step S30.
  • the electronic control unit ECU adjusts the precharge target hydraulic pressure in step S40 based on the acquired accelerator opening and brake pedal stroke.
  • the ROM stores a map associating a decreasing gradient of the accelerator opening (a rate of change of the accelerator pedal operation amount in the pedal return direction) with an adjustment amount of the precharge target hydraulic pressure.
  • the adjustment amount of the precharge target hydraulic pressure is set so that the adjustment amount increases as the decrease gradient becomes steeper according to the decrease gradient when the decrease gradient of the accelerator opening becomes larger than a predetermined value.
  • an upper limit value (for example, 0.5 MPa) can be set as the adjustment amount of the precharge target hydraulic pressure.
  • the electronic control unit ECU sets the final precharge target hydraulic pressure by adding the adjustment amount in step S40 to the precharge target hydraulic pressure calculated in step S20.
  • FIG. 5 shows an operation when the driver shifts from the accelerator pedal operation to the brake pedal operation.
  • the precharge target hydraulic pressure adjusted according to the decreasing gradient of the accelerator opening is set (solid line).
  • the motor MT and the linear electromagnetic valves PC1 and PC2 of the hydraulic unit HU are controlled by the electronic control unit ECU according to the precharge target hydraulic pressure
  • the actual value (actual hydraulic pressure) of the wheel cylinder hydraulic pressure Pw ** is pre-set. It changes so as to follow the charge target hydraulic pressure (broken line). Since the accelerator opening is kept constant at a value larger than the predetermined value before time t11, the electronic control unit ECU determines that the driver intends to further accelerate the vehicle, and the precharge target hydraulic pressure is determined. The control according to is not performed.
  • the electronic control unit ECU raises the precharge target hydraulic pressure by a predetermined amount accordingly.
  • the increase amount of the precharge target hydraulic pressure can be increased as the increase speed of the brake pedal stroke is increased.
  • the electronic control unit ECU calculates the hydraulic pressure (driver target hydraulic pressure) corresponding to the braking force requested by the driver according to the brake pedal stroke (dashed line). The actual hydraulic pressure changes so as to be equal to the larger one of the precharge target hydraulic pressure and the driver target hydraulic pressure.
  • the electronic control unit ECU determines that the precharge control is no longer necessary, and gradually decreases the precharge target hydraulic pressure.
  • the electronic control unit ECU ends the precharge control.
  • the master cylinder hydraulic pressure Pm and the wheel cylinder hydraulic pressure Pw ** can be regarded as substantially the same at the timing when the actual hydraulic pressure exceeds the precharge target hydraulic pressure, the electronic control unit ECU Based on the detected value, the precharge target hydraulic pressure can be gradually decreased.
  • the precharge target hydraulic pressure adjusted according to the decreasing gradient of the accelerator opening before the timing t13 when the driver starts the operation of the brake pedal BP when in the fade state. Is set.
  • the reservoir RS and the pressure chambers 13a and 13b communicate with each other, so that the brake fluid can be sucked from the reservoir RS, and the consumption amount of the brake fluid in the pressure chamber of the master cylinder MC can be reduced. Can be reduced. Therefore, the master cylinder can be prevented from being enlarged.
  • the precharge target hydraulic pressure is raised by a predetermined amount at the timing t13 when the operation of the brake pedal BP is started.
  • FIG. 6 shows the operation when the driver does not shift to the brake pedal operation.
  • the period from time t21 to time t22 is the same as the period from time t11 to time t12 in FIG.
  • the brake pedal stroke does not increase thereafter.
  • the elapsed time (precharge execution time) from the time t21 when the precharge control is started or the time t22 when the precharge target hydraulic pressure is suddenly increased passes the predetermined time without increasing the brake pedal stroke. In this case, the precharge target hydraulic pressure is gradually decreased, and the precharge control is finished (time t23 to t24).
  • FIG. 7 shows the operation when the driver increases the accelerator pedal operation amount again. From time t31 to time t32, the precharge target hydraulic pressure adjusted according to the decreasing gradient of the accelerator opening is set, but after time t32, the accelerator opening starts to increase again. Based on the increase in accelerator opening, the electronic control unit ECU determines that the driver has no sign of shifting from the accelerator pedal operation to the brake pedal operation, gradually decreases the precharge target hydraulic pressure, and performs the precharge control. The process ends (time t32 to t33).
  • the brake fluid consumption in the pressure chamber of the master cylinder MC is reduced by sucking the brake fluid from the reservoir RS before the driver operates the brake pedal BP in the fade state. Can be reduced.
  • the precharge by the hydraulic pressure unit HU it is possible to suppress an increase in the size of the master cylinder.
  • the fade state based on the temperature-related value related to the pad temperature and supplying brake fluid to the wheel cylinder W ** in advance, it is possible to avoid the fact that the actual deceleration is insufficient.
  • the pressure response at the time can be improved.
  • a wheel cylinder hydraulic pressure Pw ** having a required magnitude can be obtained in a required scene.
  • the present invention is not limited to the above embodiment.
  • the electronic control unit ECU when the actual hydraulic pressure exceeds the precharge target hydraulic pressure, the electronic control unit ECU gradually decreases the precharge target hydraulic pressure, but this is not a limitation.
  • the driver target hydraulic pressure exceeds the precharge target hydraulic pressure
  • the actual hydraulic pressure also exceeds the precharge target hydraulic pressure, so the electronic control unit ECU gradually decreases the precharge target hydraulic pressure based on the driver target hydraulic pressure. Can start.
  • the electronic control unit ECU gradually decreases the precharge target hydraulic pressure when the precharge execution time elapses a predetermined time without increasing the brake pedal stroke, but the present invention is not limited to this.
  • the precharge target hydraulic pressure may be gradually decreased based on the fact that the vehicle speed has become lower than the predetermined speed.
  • the precharge may be immediately terminated or may not be performed.
  • the precharge control may be canceled based on the amount of increase in the accelerator opening, in addition to the increase in the accelerator opening described with reference to FIG. You may cancel based on.
  • FIG. 1 does not include a sensor for measuring wheel cylinder hydraulic pressure
  • one or a plurality of wheel cylinder hydraulic pressure sensors may be provided. The hydraulic pressure can be adjusted more accurately based on the measured value of the wheel cylinder hydraulic pressure sensor.
  • the precharge is performed on all four wheels.
  • the present invention is not limited to this. Precharging may be performed on only one of the two hydraulic circuits. For example, by controlling only the linear solenoid valve PC1 of the system related to the left and right front wheels FR and FL among the linear solenoid valves PC1 and PC2 according to the precharge target hydraulic pressure, the braking effect is improved as compared with the left and right rear wheels RR and RL. Only the high left and right front wheels FR and FL can be precharged.
  • Precharge is because the brake fluid is supplied to the wheel cylinder W ** in advance before the driver operates the brake pedal BP more than a predetermined amount, so that the driver may feel uncomfortable depending on how the deceleration is applied. Deceleration can be appropriately suppressed by executing only one system for precharging. When precharging is performed in both the front and rear systems, the rotational speed of the motor MT may decrease due to the large load on the motor MT. On the other hand, since the load of the motor MT is reduced by using only one system of pressurization by precharging, the boosting response can be improved.
  • the liquid consumption of the wheel cylinders W ** of the left and right rear wheels RR and RL is smaller than that of the left and right front wheels FR and FL. Therefore, the master cylinder MC is configured so that the amount of fluid in the system related to the left and right rear wheels RR and RL can be covered.
  • the vehicular braking device can be configured so as to compensate for the insufficient amount of liquid by executing precharge only on the system side related to the left and right front wheels FR, FL with a larger amount of liquid consumption.
  • the physique of the master cylinder MC is large enough to secure the liquid volume of the system related to the left and right rear wheels RR and RL (the size of bottoming for the system related to the left and right front wheels FR and FL). Therefore, the master cylinder MC can be reduced.
  • precharging may be executed only on the system side related to the left and right rear wheels RR and RL in the two hydraulic systems of the front and rear systems.
  • the braking of the left and right rear wheels RR and RL is less likely to cause deceleration of the vehicle. Therefore, by executing precharge only on the system side related to the left and right rear wheels RR and RL, a natural brake feeling that does not cause a sense of incongruity to the driver can be obtained.

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  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Regulating Braking Force (AREA)

Abstract

A braking device, provided with: a reservoir; a master cylinder in which when the amount of operation performed on a brake pedal reaches or exceeds a predetermined amount, a port communicating between a pressure chamber and the reservoir is cut off and a hydraulic pressure corresponding to the amount of operation performed on the brake pedal is generated; a hydraulic pressure unit for adjusting the hydraulic pressure of a wheel cylinder; and an electronic control unit for controlling the hydraulic pressure unit. The electronic control unit determines, on the basis of a temperature-related value related to the temperature of a friction member pressed by the hydraulic pressure of the wheel cylinder against a rotating member fixed to a wheel, whether or not the friction member is in a fade state. Upon determining that the friction member is in a fade state, the electronic control unit controls the hydraulic pressure unit so as to perform a pre-charge in which a brake fluid is suctioned from the reservoir through the port during a period in which the port is communicating between the pressure chamber and the reservoir, and fed to the wheel cylinder.

Description

車両用制動装置Braking device for vehicle
　本発明は、車両用制動装置に関する。 The present invention relates to a vehicle braking device.
　従来、制動時に摩擦面が高温になるにつれ、摩擦係数（ブレーキの効き）が次第に低下していくフェードと呼ばれる現象が知られている。フェードによる減速度の低下を抑制するため液圧ユニットによりホイールシリンダ液圧を増圧する場合、マスタシリンダのピストンが底付き（ボトミング）してしまうと、それ以上ホイールシリンダ液圧を増圧することができなくなってしまう。フェード時にもボトミングしないようにするには、マスタシリンダの大型化が必要となる。 Conventionally, a phenomenon called fading is known in which the friction coefficient (the effectiveness of the brake) gradually decreases as the friction surface becomes hot during braking. When the wheel cylinder hydraulic pressure is increased by the hydraulic unit to suppress the decrease in deceleration due to fading, if the master cylinder piston bottoms (bottoming), the wheel cylinder hydraulic pressure can be increased further. It will disappear. To prevent bottoming even during fading, it is necessary to increase the size of the master cylinder.
　この点に関し、特許文献１には、リザーバからマスタシリンダの圧力室へのブレーキ液の流れを許容する逆止弁を設けることが記載されている。制動操作があるとマスタシリンダ液圧と車両の減速度とに基づいて、フェード状態にあるか否かが判定される。フェード状態にあると判定した場合、液圧ユニットが逆止弁を介してリザーバのブレーキ液を吸引し、ホイールシリンダへ供給する。これにより、マスタシリンダの大型化とフェードによる減速度の低下とを抑制することができる。 In this regard, Patent Document 1 describes that a check valve that allows the flow of brake fluid from the reservoir to the pressure chamber of the master cylinder is provided. When there is a braking operation, it is determined whether or not the vehicle is in a fade state based on the master cylinder hydraulic pressure and the deceleration of the vehicle. When it is determined that the vehicle is in the fade state, the hydraulic unit sucks the brake fluid in the reservoir through the check valve and supplies it to the wheel cylinder. Thereby, the enlargement of a master cylinder and the fall of the deceleration by a fade can be suppressed.
　しかしながら、特許文献１に記載の構成は、逆止弁の追加による部品点数の増加、コストの上昇、重量の増加が避けられない。また、制動操作時のマスタシリンダ液圧と車両の減速度とに基づいてフェード状態の判定をするため、一時的に減速度が不足することも考えられる。 However, the configuration described in Patent Document 1 cannot avoid an increase in the number of parts, an increase in cost, and an increase in weight due to the addition of a check valve. Further, since the fade state is determined based on the master cylinder hydraulic pressure at the time of braking operation and the deceleration of the vehicle, the deceleration may be temporarily insufficient.
特開２０１３－７１７１４号公報JP 2013-71714 A
　本発明は、上記問題に対処するためになされたものであり、その目的は、マスタシリンダを大型化することなくフェード時の加圧性能を向上する車両用制動装置を提供することにある。 The present invention has been made to address the above-described problems, and an object of the present invention is to provide a vehicle braking device that improves the pressurization performance during fading without increasing the size of the master cylinder.
　本発明に係る車両用制動装置は、ブレーキ液を貯留するリザーバ（ＲＳ）と、ブレーキペダル（ＢＰ）の操作量が所定量以上になると圧力室（１３ａ、１３ｂ）と前記リザーバ（ＲＳ）とを連通するポート（１２ａ、１２ｂ）が遮断されて前記ブレーキペダル（ＢＰ）の操作量に応じた液圧を発生するマスタシリンダ（ＭＣ）と、前記マスタシリンダ（ＭＣ）とホイールシリンダ（Ｗfr、Ｗfl、Ｗrr、Ｗrl）との間に設けられ、前記ホイールシリンダ（Ｗfr、Ｗfl、Ｗrr、Ｗrl）の液圧を調整する液圧ユニット（ＨＵ）と、前記液圧ユニット（ＨＵ）を制御する電子制御ユニット（ＥＣＵ）と、を備える。本発明に係る車両用制動装置の特徴は、前記電子制御ユニット（ＥＣＵ）が、車輪（ＦＲ、ＦＬ、ＲＲ、ＲＬ）に固定された回転部材に前記ホイールシリンダ（Ｗfr、Ｗfl、Ｗrr、Ｗrl）の液圧によって押圧される摩擦部材の温度に関連する温度関連値に基づいて、前記摩擦部材がフェード状態にあるか否かを判定し、前記フェード状態にあると判定した場合、前記ポート（１２ａ、１２ｂ）が前記圧力室（１３ａ、１３ｂ）と前記リザーバ（ＲＳ）とを連通している期間に前記ポート（１２ａ、１２ｂ）を介して前記リザーバ（ＲＳ）から前記ブレーキ液を吸引し、前記ホイールシリンダ（Ｗfr、Ｗfl、Ｗrr、Ｗrl）へ供給するプリチャージを実行するように前記液圧ユニット（ＨＵ）を制御するように構成されたこと、にある。 The vehicular braking apparatus according to the present invention includes a reservoir (RS) for storing brake fluid, a pressure chamber (13a, 13b), and the reservoir (RS) when an operation amount of a brake pedal (BP) exceeds a predetermined amount. A master cylinder (MC) that generates a hydraulic pressure corresponding to an operation amount of the brake pedal (BP) by shutting off the communicating ports (12a, 12b), the master cylinder (MC), and a wheel cylinder (Wfr, Wfl, Wrr, Wrl), a hydraulic unit (HU) for adjusting the hydraulic pressure of the wheel cylinder (Wfr, Wfl, Wrr, Wrl), and an electronic control unit for controlling the hydraulic unit (HU) (ECU). The vehicle braking device according to the present invention is characterized in that the electronic control unit (ECU) is connected to a wheel member (Wfr, Wfl, Wrr, Wrl) on a rotating member fixed to a wheel (FR, FL, RR, RL). If the friction member is in a fade state based on a temperature-related value related to the temperature of the friction member pressed by the hydraulic pressure, the port (12a) , 12b) sucks the brake fluid from the reservoir (RS) through the ports (12a, 12b) during a period in which the pressure chambers (13a, 13b) and the reservoir (RS) are communicated, The hydraulic unit (HU) is configured to perform precharging to be supplied to the wheel cylinders (Wfr, Wfl, Wrr, Wrl).
　ここにおいて、前記電子制御ユニット（ＥＣＵ）は、前記温度関連値に基づいて、前記プリチャージ実行時の前記ホイールシリンダ（Ｗfr、Ｗfl、Ｗrr、Ｗrl）の液圧の目標値を演算するように構成されてもよい。 Here, the electronic control unit (ECU) is configured to calculate a target value of the hydraulic pressure of the wheel cylinder (Wfr, Wfl, Wrr, Wrl) when the precharge is performed based on the temperature related value. May be.
　上記本発明の特徴によれば、フェード状態においてドライバーがブレーキペダルを所定量以上操作する前にリザーバからブレーキ液を吸引することで、マスタシリンダの圧力室内のブレーキ液の消費量を低減することができる。そのため、マスタシリンダの大型化を抑制することができる。摩擦部材の温度に関連する温度関連値に基づいてフェード状態を判定し、予めホイールシリンダにブレーキ液を供給することで、実際に減速度が不足することを回避することができる。また、必要とされるホイールシリンダ液圧はフェード状態の程度に応じて変化する。そこで、温度関連値に基づいてプリチャージ実行時のホイールシリンダ液圧の目標値を演算する構成により、フェード状態の程度に合わせてフェード時の加圧応答性を向上することができる。 According to the above-described feature of the present invention, the brake fluid consumption in the pressure chamber of the master cylinder can be reduced by sucking the brake fluid from the reservoir before the driver operates the brake pedal more than a predetermined amount in the fade state. it can. Therefore, the master cylinder can be prevented from being enlarged. By determining the fade state based on the temperature-related value related to the temperature of the friction member and supplying the brake fluid to the wheel cylinder in advance, it is possible to avoid an actual lack of deceleration. Further, the required wheel cylinder hydraulic pressure varies depending on the degree of the fade state. Therefore, by applying the target value of the wheel cylinder hydraulic pressure at the time of executing the precharge based on the temperature related value, it is possible to improve the pressurization response during the fade according to the degree of the fade state.
　また、前記電子制御ユニット（ＥＣＵ）は、アクセルペダル操作量の減少速度が大きいほど、又は、ブレーキペダル操作量の増加速度が大きいほど、前記目標値を大きな値に調整するように構成されてもよい。
　アクセルペダル操作量の減少速度が大きいほど、その後に急な制動操作が行われる蓋然性が高い。ブレーキペダル操作量の増加速度が大きいほど、多くのブレーキ液をプリチャージによりホイールシリンダに供給すべきである。そこで、アクセルペダル操作量の減少速度が大きいほど、又は、ブレーキペダル操作量の増加速度が大きいほど、プリチャージによるホイールシリンダ液圧の目標値を大きくする構成により、ブレーキペダル操作量が所定量以上になる前に、リザーバ内のブレーキ液をホイールシリンダに確実かつ十分に供給することができ、ひいてはフェード時の加圧応答性を一層高めることができる。 Further, the electronic control unit (ECU) may be configured to adjust the target value to a larger value as the decrease speed of the accelerator pedal operation amount is larger or as the increase speed of the brake pedal operation amount is larger. Good.
The greater the rate of decrease in the accelerator pedal operation amount, the higher the probability that a sudden braking operation will be performed thereafter. The greater the increase rate of the brake pedal operation amount, the more brake fluid should be supplied to the wheel cylinder by precharging. Therefore, by setting the target value of the wheel cylinder hydraulic pressure by precharging to be larger as the decrease rate of the accelerator pedal operation amount is larger or the increase rate of the brake pedal operation amount is larger, the brake pedal operation amount is more than a predetermined amount. Before it becomes, the brake fluid in the reservoir can be reliably and sufficiently supplied to the wheel cylinder, and as a result, pressurization response at the time of fading can be further enhanced.
　また、前記電子制御ユニット（ＥＣＵ）は、前記プリチャージ実行時に前記車両のドライバーの操作態様に応じて前記目標値の漸減を開始し、前記目標値がゼロになると前記プリチャージの実行を終了するように構成されてもよい。
　プリチャージはドライバーがブレーキペダルを所定量以上操作する前に予めホイールシリンダにブレーキ液を供給するため、ドライバーの操作態様から、これ以上プリチャージの必要がないと判断できる場合には終了することが望ましい。そこで、ドライバーの操作態様に応じてプリチャージによるホイールシリンダ液圧の目標値の漸減を開始し、目標値がゼロになったときにプリチャージを終了する構成により、不要なプリチャージの継続を避けることができる。 The electronic control unit (ECU) starts gradually decreasing the target value according to the operation mode of the driver of the vehicle at the time of executing the precharge, and ends the execution of the precharge when the target value becomes zero. It may be configured as follows.
Since pre-charge supplies brake fluid to the wheel cylinder in advance before the driver operates the brake pedal more than a predetermined amount, the pre-charge may end when it can be determined from the driver's operation that no further pre-charge is necessary. desirable. Therefore, the continuation of unnecessary precharge is avoided by starting the gradual reduction of the target value of the wheel cylinder hydraulic pressure by precharging according to the operation mode of the driver and terminating the precharging when the target value becomes zero. be able to.
　また、前記車両が前後２系統のブレーキ液圧回路を備える場合、前記電子制御ユニット（ＥＣＵ）は、前輪（ＦＲ、ＦＬ）系統又は後輪（ＲＲ、ＲＬ）系統の何れか一方にだけ前記プリチャージを実行するように前記液圧ユニット（ＨＵ）を制御してもよい。
　プリチャージによる加圧を２系統の液圧回路のうち１系統だけにすることで昇圧応答性を高めることができる。一般に前輪と比べて後輪のホイールシリンダの消費液量の方が小さいため、後輪系統の液量をまかなうことができるようにマスタシリンダを構成し、より消費液量の多い前輪系統で不足する液量をプリチャージで補うようにすれば、マスタシリンダを小さくすることができる。また、一般に後輪のブレーキの方が車両の減速度が発生し難いため、後輪系統側だけプリチャージを実行するようにした場合には、自然なブレーキフィーリングとなり得る。 In addition, when the vehicle includes two front and rear brake fluid pressure circuits, the electronic control unit (ECU) is connected to the front wheel (FR, FL) system or the rear wheel (RR, RL) system only in the pre-train. The hydraulic unit (HU) may be controlled to perform charging.
The pressurization response can be enhanced by applying pre-pressurization to only one of the two hydraulic circuits. In general, the liquid consumption of the rear wheel cylinder is smaller than that of the front wheels, so the master cylinder is configured to cover the liquid volume of the rear wheel system, and the front wheel system with higher liquid consumption is insufficient. If the amount of liquid is supplemented by precharging, the master cylinder can be made smaller. In general, the rear wheel brake is less likely to cause deceleration of the vehicle. Therefore, when precharge is executed only on the rear wheel system side, a natural brake feeling can be obtained.
本発明の実施形態に係る車両用制動装置の概略構成図である。1 is a schematic configuration diagram of a vehicle braking device according to an embodiment of the present invention. 図１に示した電子制御ユニットＥＣＵが実行する制御のフローチャートである。It is a flowchart of the control which electronic control unit ECU shown in FIG. 1 performs. 本発明の実施形態に係る車両用制動装置の動作を説明するタイムチャート（その１）である。It is a time chart (the 1) explaining operation | movement of the braking device for vehicles which concerns on embodiment of this invention. アクセル開度の減少勾配とプリチャージ目標液圧の調整量とを対応付けるマップの一例である。It is an example of the map which matches the decreasing amount of an accelerator opening, and the adjustment amount of a precharge target hydraulic pressure. 本発明の実施形態に係る車両用制動装置の動作を説明するタイムチャート（その２）である。It is a time chart (the 2) explaining operation | movement of the braking device for vehicles which concerns on embodiment of this invention. 本発明の実施形態に係る車両用制動装置の動作を説明するタイムチャート（その３）である。It is a time chart (the 3) explaining operation | movement of the braking device for vehicles which concerns on embodiment of this invention. 本発明の実施形態に係る車両用制動装置の動作を説明するタイムチャート（その４）である。It is a time chart (the 4) explaining operation | movement of the braking device for vehicles which concerns on embodiment of this invention.
　以下、本発明の実施形態について図面を参照しつつ説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　図１は、本発明の実施形態に係る車両用制動装置の概略構成を示している。以下、各種変数等の末尾に付された「**」は、各種変数等が車輪ＦＲ、ＦＬ、ＲＲ、ＲＬのいずれに関するものであるかを示すために各種変数等の末尾に付される「fr」，「fl」等の包括表記である。 FIG. 1 shows a schematic configuration of a vehicle braking apparatus according to an embodiment of the present invention. In the following, “**” added to the end of various variables or the like is attached to the end of the various variables or the like to indicate whether the various variables or the like relates to the wheels FR, FL, RR, or RL. Inclusive notation such as “fr” and “fl”.
　車両用制動装置は、車輪**にホイールシリンダ液圧による摩擦制動力を発生させる。図１に示すように、本実施形態の制動装置は、ブレーキペダルＢＰの操作力を増幅する倍力装置１１と、ブレーキペダルＢＰの操作量（ストローク、或いは、踏力）に応じた液圧を発生するマスタシリンダＭＣと、ブレーキ液を貯留するリザーバＲＳと、車輪**に配置されたホイールシリンダＷ**に供給されるホイールシリンダ液圧を調整可能な液圧ユニットＨＵと、液圧ユニットＨＵを制御する電子制御ユニットＥＣＵと、を含んで構成されている。車輪**では、Ｗ**のホイールシリンダ液圧に応じた押圧力で摩擦部材（例えば、ブレーキパッド）が車輪と一体回転する回転部材（例えば、ブレーキディスク）に押し付けられることによって、前記ホイールシリンダ液圧に応じた摩擦制動力が付与される。 * Vehicle braking devices generate friction braking force by wheel cylinder hydraulic pressure on wheels **. As shown in FIG. 1, the braking device of the present embodiment generates a hydraulic pressure corresponding to the booster 11 that amplifies the operating force of the brake pedal BP and the operation amount (stroke or pedaling force) of the brake pedal BP. A master cylinder MC, a reservoir RS for storing brake fluid, a hydraulic unit HU capable of adjusting the hydraulic pressure of the wheel cylinder supplied to a wheel cylinder W ** disposed on the wheel **, and a hydraulic unit HU And an electronic control unit ECU to be controlled. In the wheel **, a friction member (for example, a brake pad) is pressed against a rotating member (for example, a brake disc) that rotates integrally with the wheel with a pressing force corresponding to the wheel cylinder hydraulic pressure of W **, thereby the wheel cylinder. A friction braking force corresponding to the hydraulic pressure is applied.
　倍力装置１１は、例えば、負圧ブースタ、液圧ブースタ、電動ブースタなどが採用され得る。本実施形態のマスタシリンダＭＣは、シリンダ本体内に直列に配置された２つのピストンによって区画される２つの圧力室１３ａ、１３ｂを有するタンデム型のマスタシリンダである。ブレーキペダルＢＰが操作されておらず、各ピストンが初期位置にあるとき、連通ポート１２ａ、１２ｂを介してリザーバＲＳと圧力室１３ａ、１３ｂとは連通している。ブレーキペダルＢＰが操作され、連通ポート１２ａ、１２ｂが遮断される位置まで各ピストンが前進すると、ブレーキペダルＢＰの操作量に応じた液圧（マスタシリンダ液圧Ｐｍ）が圧力室１３ａ、１３ｂに発生する。マスタシリンダＭＣは、マスタシリンダ液圧Ｐｍを２つの出力ポート１４ａ、１４ｂから出力するようになっている。 As the booster 11, for example, a negative pressure booster, a hydraulic pressure booster, an electric booster or the like can be adopted. The master cylinder MC of the present embodiment is a tandem type master cylinder having two pressure chambers 13a and 13b defined by two pistons arranged in series in the cylinder body. When the brake pedal BP is not operated and each piston is in the initial position, the reservoir RS and the pressure chambers 13a and 13b communicate with each other via the communication ports 12a and 12b. When the brake pedal BP is operated and each piston advances to a position where the communication ports 12a and 12b are blocked, a hydraulic pressure (master cylinder hydraulic pressure Pm) corresponding to the operation amount of the brake pedal BP is generated in the pressure chambers 13a and 13b. To do. The master cylinder MC outputs the master cylinder hydraulic pressure Pm from the two output ports 14a and 14b.
　液圧ユニットＨＵは、リニア電磁弁ＰＣ１、ＰＣ２と、ブレーキ液圧調整部３３～３６と、還流ブレーキ液供給部３７と、を含んで構成されている。マスタシリンダＭＣの一方の出力ポート１４ａとブレーキ液圧調整部３３、３４の上流部との間に常開リニア電磁弁ＰＣ１が介装され、マスタシリンダＭＣの他方の出力ポート１４ｂとブレーキ液圧調整部３５、３６の上流部との間に常開リニア電磁弁ＰＣ２が介装されている。リニア電磁弁ＰＣ１、ＰＣ２の詳細については後述する。 The hydraulic unit HU includes linear solenoid valves PC1 and PC2, brake fluid pressure adjusting units 33 to 36, and a reflux brake fluid supply unit 37. A normally open linear solenoid valve PC1 is interposed between one output port 14a of the master cylinder MC and the upstream portion of the brake fluid pressure adjusting unit 33, 34, and the other output port 14b of the master cylinder MC and the brake fluid pressure adjustment. A normally open linear solenoid valve PC2 is interposed between the upstream portions of the portions 35 and 36. Details of the linear solenoid valves PC1 and PC2 will be described later.
　ブレーキ液圧調整部３３～３６は、２ポート２位置切換型の常開電磁開閉弁である増圧弁ＰＵ**と、２ポート２位置切換型の常閉電磁開閉弁である減圧弁ＰＤ**とで構成されている。増圧弁ＰＵ**は、ブレーキ液圧調整部３３～３６のうち対応する調整部の上流部とホイールシリンダＷ**とを連通・遮断できるようになっている。減圧弁ＰＤ**は、ホイールシリンダＷ**とリザーバＲＳ１、ＲＳ２のうち対応するリザーバとを連通・遮断できるようになっている。この結果、増圧弁ＰＵ**、及び減圧弁ＰＤ**を制御することでホイールシリンダＷ**の液圧（ホイールシリンダ液圧Ｐｗ**）が増圧・保持・減圧され得るようになっている。 The brake fluid pressure adjusting units 33 to 36 include a pressure-increasing valve PU ** which is a 2-port 2-position switching type normally open electromagnetic on-off valve, and a pressure reducing valve PD ** which is a 2-port 2-position switching type normally closed electromagnetic on-off valve. It consists of and. The pressure increasing valve PU ** can communicate / block the upstream portion of the corresponding adjusting portion of the brake fluid pressure adjusting portions 33 to 36 and the wheel cylinder W **. The pressure reducing valve PD ** can communicate / block the wheel cylinder W ** and the corresponding one of the reservoirs RS1 and RS2. As a result, the hydraulic pressure of the wheel cylinder W ** (wheel cylinder hydraulic pressure Pw **) can be increased, held and reduced by controlling the pressure increasing valve PU ** and the pressure reducing valve PD **. Yes.
　還流ブレーキ液供給部３７は、直流モータＭＴと、モータＭＴにより同時に駆動される２つの液圧ポンプ（ギヤポンプ）ＨＰ１、ＨＰ２を含んでいる。液圧ポンプＨＰ１、ＨＰ２は、減圧弁ＰＤ**から還流されてきたリザーバＲＳ１、ＲＳ２内のブレーキ液をそれぞれ汲み上げ、汲み上げたブレーキ液をブレーキ液圧調整部３３～３６の上流部にそれぞれ供給するようになっている。また、液圧ポンプＨＰ１、ＨＰ２は、マスタシリンダＭＣの圧力室１３ａ、１３ｂがリザーバＲＳと連通しているとき、連通ポート１２ａ、１２ｂを介してリザーバＲＳ内のブレーキ液をそれぞれ吸引し、吸引したブレーキ液をブレーキ液圧調整部３３～３６の上流部にそれぞれ供給するようになっている。 The reflux brake fluid supply unit 37 includes a DC motor MT and two hydraulic pumps (gear pumps) HP1 and HP2 that are simultaneously driven by the motor MT. The hydraulic pumps HP1 and HP2 pump up the brake fluid in the reservoirs RS1 and RS2 returned from the pressure reducing valve PD **, and supply the pumped brake fluid to upstream portions of the brake fluid pressure adjusting units 33 to 36, respectively. It is like that. Further, when the pressure chambers 13a and 13b of the master cylinder MC communicate with the reservoir RS, the hydraulic pumps HP1 and HP2 respectively suck and suck the brake fluid in the reservoir RS via the communication ports 12a and 12b. The brake fluid is supplied to upstream portions of the brake fluid pressure adjusting units 33 to 36, respectively.
　次に、常開リニア電磁弁ＰＣ１、ＰＣ２について説明する。常開リニア電磁弁ＰＣ１、ＰＣ２の弁体には、図示しないコイルスプリングからの付勢力に基づく開方向の力が常時作用しているとともに、ブレーキ液圧調整部３３～３６のうち対応する調整部の上流部の圧力からマスタシリンダ液圧Ｐｍを減じることで得られる差圧（リニア弁差圧ΔＰ）に基づく開方向の力と、常開リニア電磁弁ＰＣ１、ＰＣ２に供給される電流（指令電流Ｉｄ）に応じて比例的に増加する吸引力に基づく閉方向の力が作用するようになっている。 Next, the normally open linear solenoid valves PC1 and PC2 will be described. A force in an opening direction based on a biasing force from a coil spring (not shown) is constantly applied to the valve bodies of the normally open linear electromagnetic valves PC1 and PC2, and a corresponding adjusting unit among the brake fluid pressure adjusting units 33 to 36. The force in the opening direction based on the differential pressure (linear valve differential pressure ΔP) obtained by subtracting the master cylinder hydraulic pressure Pm from the upstream pressure of the valve, and the current (command current) supplied to the normally open linear solenoid valves PC1 and PC2 A closing force based on a suction force that increases proportionally according to Id) acts.
　この結果、リニア弁差圧ΔＰの指令値である指令差圧ΔＰｄが指令電流Ｉｄに応じて比例的に増加するように決定される。常開リニア電磁弁ＰＣ１、ＰＣ２は、ΔＰｄがΔＰよりも大きいときに閉弁する一方、ΔＰｄがΔＰよりも小さいとき開弁する。この結果、液圧ポンプＨＰ１、ＨＰ２が駆動されている場合、ブレーキ液圧調整部３３～３６のうち対応する調整部の上流部のブレーキ液が常開リニア電磁弁ＰＣ１、ＰＣ２のうち対応する電磁弁を介してマスタシリンダＭＣの対応するポート側に流れることによって、リニア弁差圧ΔＰが指令差圧ΔＰｄに一致するように調整され得るようになっている。なお、マスタシリンダＭＣの対応するポート側へ流入したブレーキ液はリザーバＲＳ１、ＲＳ２のうち対応するリザーバへと還流される。 As a result, the command differential pressure ΔPd, which is the command value of the linear valve differential pressure ΔP, is determined so as to increase in proportion to the command current Id. The normally open linear solenoid valves PC1 and PC2 are closed when ΔPd is larger than ΔP, and are opened when ΔPd is smaller than ΔP. As a result, when the hydraulic pumps HP1 and HP2 are driven, the brake fluid upstream of the corresponding adjusting unit among the brake hydraulic pressure adjusting units 33 to 36 corresponds to the corresponding electromagnetic among the normally open linear electromagnetic valves PC1 and PC2. The linear valve differential pressure ΔP can be adjusted to coincide with the command differential pressure ΔPd by flowing to the corresponding port side of the master cylinder MC via the valve. The brake fluid that has flowed into the corresponding port side of the master cylinder MC is returned to the corresponding reservoir among the reservoirs RS1 and RS2.
　換言すれば、モータＭＴ（従って、液圧ポンプＨＰ１、ＨＰ２）が駆動されている場合、常開リニア電磁弁ＰＣ１、ＰＣ２の指令電流Ｉｄに応じてリニア弁差圧ΔＰが制御され得るようになっている。ブレーキ液圧調整部３３～３６の上流部の圧力は、マスタシリンダ液圧Ｐｍにリニア弁差圧ΔＰを加算した値（Ｐｍ＋ΔＰ）となる。なお、リニア弁差圧ΔＰがゼロより大きい値に調整されている状態において液圧ポンプＨＰ１、ＨＰ２の駆動が停止された後は、指令電流Ｉｄを減少方向に調整することによって、リニア弁差圧ΔＰを減少方向のみにおいてなお継続して調整することができる。 In other words, when the motor MT (and hence the hydraulic pumps HP1 and HP2) is driven, the linear valve differential pressure ΔP can be controlled in accordance with the command current Id of the normally open linear electromagnetic valves PC1 and PC2. ing. The pressure upstream of the brake fluid pressure adjusting units 33 to 36 is a value (Pm + ΔP) obtained by adding the linear valve differential pressure ΔP to the master cylinder fluid pressure Pm. Note that after the hydraulic pumps HP1 and HP2 are stopped in a state where the linear valve differential pressure ΔP is adjusted to a value larger than zero, the linear valve differential pressure is adjusted by adjusting the command current Id in the decreasing direction. ΔP can still be adjusted only in the decreasing direction.
　常開リニア電磁弁ＰＣ１、ＰＣ２を非励磁状態にすると（即ち、指令電流Ｉｄを「０」に設定すると）、ＰＣ１、ＰＣ２はコイルスプリングの付勢力により開状態を維持するようになっている。このとき、リニア弁差圧ΔＰが「０」になって、ブレーキ液圧調整部３３～３６の上流部の圧力がマスタシリンダ液圧Ｐｍと等しくなる。また、常開リニア電磁弁ＰＣ１、ＰＣ２が非励磁状態でも、液圧ポンプＨＰ１、ＨＰ２を駆動するとＰＣ１、ＰＣ２のオリフィスによりブレーキ液圧調整部３３～３６の上流部の圧力をマスタシリンダ液圧Ｐｍよりいくらか高くすることができる。なお、ブレーキ液圧調整部３３～３６の上流部の圧力より高いマスタシリンダ液圧Ｐｍが発生すると、常開リニア電磁弁ＰＣ１、ＰＣ２と並列に接続された一方向弁によりブレーキ液がマスタシリンダＭＣからブレーキ液圧調整部３３～３６の上流部に流入する。 When the normally open linear solenoid valves PC1 and PC2 are in a non-excited state (that is, when the command current Id is set to “0”), the PC1 and PC2 are maintained in the open state by the biasing force of the coil spring. At this time, the linear valve differential pressure ΔP becomes “0”, and the pressure upstream of the brake fluid pressure adjusting units 33 to 36 becomes equal to the master cylinder fluid pressure Pm. Even when the normally open linear solenoid valves PC1 and PC2 are in a non-excited state, when the hydraulic pumps HP1 and HP2 are driven, the pressures upstream of the brake hydraulic pressure adjusting units 33 to 36 are controlled by the orifices of the PC1 and PC2 to the master cylinder hydraulic pressure Pm. Can be somewhat higher. When a master cylinder fluid pressure Pm higher than the pressure upstream of the brake fluid pressure adjusters 33 to 36 is generated, the brake fluid is supplied to the master cylinder MC by a one-way valve connected in parallel with the normally open linear solenoid valves PC1 and PC2. Flows into the upstream portion of the brake fluid pressure adjusting section 33-36.
　以上、説明した構成により、本実施形態の制動装置は、左右前輪ＦＲ、ＦＬに係わる系統と、左右後輪ＲＲ、ＲＬに係わる系統の２系統の液圧回路から構成されている。制動装置は、全ての電磁弁が非励磁状態にあるとき、ホイールシリンダ液圧Ｐｗ**がマスタシリンダ液圧Ｐｍと等しい値に調整される。 With the configuration described above, the braking device of the present embodiment includes two hydraulic circuits, a system related to the left and right front wheels FR and FL and a system related to the left and right rear wheels RR and RL. The brake device adjusts the wheel cylinder hydraulic pressure Pw ** to a value equal to the master cylinder hydraulic pressure Pm when all the solenoid valves are in the non-excited state.
　他方、この状態にて、モータＭＴ（従って、液圧ポンプＨＰ１，ＨＰ２）を駆動するとともに常開リニア電磁弁ＰＣ１，ＰＣ２を制御することによって、ホイールシリンダ液圧Ｐｗ**が液圧（Ｐｍ＋ΔＰ）に調整される。更には、増圧弁ＰＵ**、及び減圧弁ＰＤ**を制御することで、ホイールシリンダ液圧Ｐｗ**が車輪毎に独立して調整され得る。即ち、ドライバーによるブレーキペダルＢＰの操作にかかわらず、車輪**に付与される制動力が車輪毎に独立して調整され得る。 On the other hand, in this state, the wheel cylinder hydraulic pressure Pw ** is set to the hydraulic pressure (Pm + ΔP) by driving the motor MT (therefore, the hydraulic pumps HP1, HP2) and controlling the normally open linear solenoid valves PC1, PC2. Adjusted to Furthermore, the wheel cylinder hydraulic pressure Pw ** can be independently adjusted for each wheel by controlling the pressure increasing valve PU ** and the pressure reducing valve PD **. That is, regardless of the operation of the brake pedal BP by the driver, the braking force applied to the wheel ** can be adjusted independently for each wheel.
　電子制御ユニットＥＣＵは、ＣＰＵ、ＲＯＭ、ＲＡＭ、及びインターフェース等を備える。インターフェースは、マスタシリンダ液圧Ｐｍを検出するマスタシリンダ液圧センサ４４を始めとして種々のセンサ／スイッチ類と接続され、ＣＰＵにセンサ／スイッチ類からの信号を供給するとともに、ＣＰＵの指示に応じて、液圧ユニットＨＵの電磁弁（常開リニア電磁弁ＰＣ１、ＰＣ２、増圧弁ＰＵ**、及び減圧弁ＰＤ**）、及びモータＭＴに駆動信号を送出するようになっている。例えば、本実施形態の電子制御ユニットＥＣＵは、車輪の回転速度を検出する車輪速度センサ、ブレーキペダルＢＰの操作の有無に応じた信号を選択的に出力するブレーキスイッチ、ブレーキペダルＢＰの操作量としてペダルストロークを検出するストロークセンサ、不図示のアクセルペダルの操作量としてアクセル開度を検出するアクセル開度センサ、前後加速度センサ、横加速度センサ、ヨーレートセンサ、等からの信号を受信可能である。ここで、センサ／スイッチ類からの信号は、他の装置から通信バスを介して取得され得る。また、車両速度は、車輪速度センサの検出結果に基づいて演算され得る。 The electronic control unit ECU includes a CPU, a ROM, a RAM, an interface, and the like. The interface is connected to various sensors / switches including a master cylinder hydraulic pressure sensor 44 that detects the master cylinder hydraulic pressure Pm, and supplies signals from the sensors / switches to the CPU, and in response to instructions from the CPU. Drive signals are sent to the solenoid valves of the hydraulic unit HU (normally open linear solenoid valves PC1, PC2, pressure increasing valve PU **, and pressure reducing valve PD **) and the motor MT. For example, the electronic control unit ECU of the present embodiment includes a wheel speed sensor that detects the rotational speed of the wheel, a brake switch that selectively outputs a signal corresponding to whether or not the brake pedal BP is operated, and an operation amount of the brake pedal BP. A signal from a stroke sensor that detects a pedal stroke, an accelerator opening sensor that detects an accelerator opening as an operation amount of an unillustrated accelerator pedal, a longitudinal acceleration sensor, a lateral acceleration sensor, a yaw rate sensor, and the like can be received. Here, signals from sensors / switches can be obtained from other devices via a communication bus. Further, the vehicle speed can be calculated based on the detection result of the wheel speed sensor.
　続いて、電子制御ユニットＥＣＵが実行する制御について、図２のフローチャートを参照しながら説明する。図２に示すように、電子制御ユニットＥＣＵは、ステップＳ１０においてブレーキパッド（本実施形態の摩擦部材）がフェード状態にあるか否かを判定し、フェード状態にない場合（ステップＳ１０：ＮＯ）、ステップＳ１０に戻る。すなわち、電子制御ユニットＥＣＵは、ブレーキパッドがフェード状態にあると判定するまでステップＳ１０で待機する。電子制御ユニットＥＣＵは、ブレーキパッドがフェード状態にあると判定すると（ステップＳ１０：ＹＥＳ）、ステップＳ２０においてプリチャージ目標液圧を演算する。 Subsequently, the control executed by the electronic control unit ECU will be described with reference to the flowchart of FIG. As shown in FIG. 2, the electronic control unit ECU determines whether or not the brake pad (the friction member of the present embodiment) is in a fade state in step S10, and if it is not in a fade state (step S10: NO), Return to step S10. That is, the electronic control unit ECU stands by in step S10 until it is determined that the brake pad is in a fade state. When the electronic control unit ECU determines that the brake pad is in a fade state (step S10: YES), the electronic control unit ECU calculates a precharge target hydraulic pressure in step S20.
　図３を参照して、上記のステップＳ１０及びステップＳ２０の処理について詳細に説明する。図３は、本実施形態に係る車両用制動装置の動作を説明するタイムチャートである。図３に示すように、加速と減速とを交互に行うと、繰り返しの制動によりブレーキパッドの温度（パッド温度）が次第に上昇する。電子制御ユニットＥＣＵは、パッド温度に基づいて、ブレーキパッドがフェード状態にあるか否かを判定する。具体的には、パッド温度がしきい値ｔｈ１以上になると、ブレーキパッドがフェード状態にあると判定する。パッド温度は、パッド温度を測定するセンサにより取得され得る。また、パッド温度は、ブレーキペダル操作時間やブレーキペダル操作回数、ブレーキペダル操作量に応じて変動し、それらが大きいほどより高温になる。さらに、パッド温度は、車両速度（運動エネルギー）に応じて変動し、ブレーキペダル操作によって熱エネルギーに変換された運動エネルギーが大きいほどより高温になる。したがって、電子制御ユニットＥＣＵは、パッド温度に関連するそれらの温度関連値（または、それらから推定したパッド温度推定値）に基づいて、ブレーキパッドがフェード状態にあるか否かを判定し得る。 With reference to FIG. 3, the processing of the above-described step S10 and step S20 will be described in detail. FIG. 3 is a time chart for explaining the operation of the vehicle braking device according to the present embodiment. As shown in FIG. 3, when acceleration and deceleration are alternately performed, the brake pad temperature (pad temperature) gradually increases due to repeated braking. The electronic control unit ECU determines whether the brake pad is in a fade state based on the pad temperature. Specifically, when the pad temperature becomes equal to or higher than the threshold value th1, it is determined that the brake pad is in a fade state. The pad temperature can be obtained by a sensor that measures the pad temperature. The pad temperature varies depending on the brake pedal operation time, the number of brake pedal operations, and the amount of brake pedal operation, and the higher the temperature, the higher the pad temperature. Furthermore, the pad temperature fluctuates according to the vehicle speed (kinetic energy), and becomes higher as the kinetic energy converted into thermal energy by operating the brake pedal increases. Therefore, the electronic control unit ECU can determine whether or not the brake pad is in a fade state based on those temperature related values related to the pad temperature (or the estimated pad temperature value estimated therefrom).
　電子制御ユニットＥＣＵは、ブレーキパッドがフェード状態にあると判定すると、パッド温度（測定値、或いは、推定値）に応じてプリチャージ目標液圧を演算する。具体的には、電子制御ユニットＥＣＵは、図３に示すように、加速から減速へと遷移するタイミングにおいて、パッド温度としきい値ｔｈ１との差が大きいほどプリチャージ目標液圧を大きく演算する。また、プリチャージ目標液圧には上限値（例えば、０．５ＭＰａ）が設定され得る。 When the electronic control unit ECU determines that the brake pad is in a fade state, the electronic control unit ECU calculates a precharge target hydraulic pressure according to the pad temperature (measured value or estimated value). Specifically, as shown in FIG. 3, the electronic control unit ECU calculates the precharge target hydraulic pressure to be larger as the difference between the pad temperature and the threshold value th1 is larger at the timing of transition from acceleration to deceleration. Further, an upper limit value (for example, 0.5 MPa) can be set for the precharge target hydraulic pressure.
　再び、図２を参照すると、電子制御ユニットＥＣＵは、ステップＳ３０においてアクセル開度と、ブレーキペダルストロークとを取得する。電子制御ユニットＥＣＵは、取得したアクセル開度とブレーキペダルストロークとに基づいて、ステップＳ４０においてプリチャージ目標液圧を調整する。例えば、ＲＯＭには、図４に示すようにアクセル開度の減少勾配（アクセルペダル操作量のペダル戻し方向への変化速度）とプリチャージ目標液圧の調整量とを対応付けるマップが格納されている。プリチャージ目標液圧の調整量は、アクセル開度の減少勾配が所定値より大きくなると、減少勾配に応じて減少勾配が急なほど調整量が大きくなるように設定される。また、プリチャージ目標液圧の調整量には上限値（例えば、０．５ＭＰａ）が設定され得る。電子制御ユニットＥＣＵは、ステップＳ２０で演算したプリチャージ目標液圧にステップＳ４０の調整量を加算することで、最終的なプリチャージ目標液圧を設定する。 Referring to FIG. 2 again, the electronic control unit ECU acquires the accelerator opening and the brake pedal stroke in step S30. The electronic control unit ECU adjusts the precharge target hydraulic pressure in step S40 based on the acquired accelerator opening and brake pedal stroke. For example, as shown in FIG. 4, the ROM stores a map associating a decreasing gradient of the accelerator opening (a rate of change of the accelerator pedal operation amount in the pedal return direction) with an adjustment amount of the precharge target hydraulic pressure. . The adjustment amount of the precharge target hydraulic pressure is set so that the adjustment amount increases as the decrease gradient becomes steeper according to the decrease gradient when the decrease gradient of the accelerator opening becomes larger than a predetermined value. Further, an upper limit value (for example, 0.5 MPa) can be set as the adjustment amount of the precharge target hydraulic pressure. The electronic control unit ECU sets the final precharge target hydraulic pressure by adding the adjustment amount in step S40 to the precharge target hydraulic pressure calculated in step S20.
　以下、図５～図７のタイムチャートを参照して、ブレーキパッドがフェード状態にある場合の動作を具体的に説明する。図５は、ドライバーがアクセルペダル操作からブレーキペダル操作へと移行した場合の動作を示している。時刻ｔ１１においてアクセル開度が減少し始めると、アクセル開度の減少勾配に応じて調整されたプリチャージ目標液圧が設定される（実線）。プリチャージ目標液圧に応じて電子制御ユニットＥＣＵにより液圧ユニットＨＵのモータＭＴ及びリニア電磁弁ＰＣ１、ＰＣ２が制御されると、ホイールシリンダ液圧Ｐｗ**の実際値（実液圧）がプリチャージ目標液圧に追随するように変化する（破線）。なお、時刻ｔ１１以前はアクセル開度が所定値より大きな値に一定に保持されていることから、電子制御ユニットＥＣＵは、ドライバーに車両を更に加速する意思があると判断し、プリチャージ目標液圧に応じた制御を行わない。 Hereinafter, the operation when the brake pads are in a fade state will be described in detail with reference to the time charts of FIGS. FIG. 5 shows an operation when the driver shifts from the accelerator pedal operation to the brake pedal operation. When the accelerator opening starts to decrease at time t11, the precharge target hydraulic pressure adjusted according to the decreasing gradient of the accelerator opening is set (solid line). When the motor MT and the linear electromagnetic valves PC1 and PC2 of the hydraulic unit HU are controlled by the electronic control unit ECU according to the precharge target hydraulic pressure, the actual value (actual hydraulic pressure) of the wheel cylinder hydraulic pressure Pw ** is pre-set. It changes so as to follow the charge target hydraulic pressure (broken line). Since the accelerator opening is kept constant at a value larger than the predetermined value before time t11, the electronic control unit ECU determines that the driver intends to further accelerate the vehicle, and the precharge target hydraulic pressure is determined. The control according to is not performed.
　時刻ｔ１２においてアクセル開度が急減すると、それに応じてプリチャージ目標液圧が急増し、それに伴い実液圧も増加する。時刻ｔ１３においてブレーキペダルストロークが立ち上がると、電子制御ユニットＥＣＵは、それに応じてプリチャージ目標液圧を所定量かさ上げする。ここで、プリチャージ目標液圧のかさ上げ量は、ブレーキペダルストロークの増加速度が大きいほど大きくされ得る。同時に、電子制御ユニットＥＣＵは、ブレーキペダルストロークに応じてドライバーが要求する制動力に対応する液圧（ドライバー目標液圧）を演算する（一点鎖線）。実液圧は、プリチャージ目標液圧とドライバー目標液圧のうち大きい方と等しくなるように変化する。 When the accelerator opening decreases sharply at time t12, the precharge target hydraulic pressure increases rapidly and the actual hydraulic pressure increases accordingly. When the brake pedal stroke rises at time t13, the electronic control unit ECU raises the precharge target hydraulic pressure by a predetermined amount accordingly. Here, the increase amount of the precharge target hydraulic pressure can be increased as the increase speed of the brake pedal stroke is increased. At the same time, the electronic control unit ECU calculates the hydraulic pressure (driver target hydraulic pressure) corresponding to the braking force requested by the driver according to the brake pedal stroke (dashed line). The actual hydraulic pressure changes so as to be equal to the larger one of the precharge target hydraulic pressure and the driver target hydraulic pressure.
　実液圧がプリチャージ目標液圧を上回ると、電子制御ユニットＥＣＵは、プリチャージ制御はもう必要ないと判断し、プリチャージ目標液圧を漸減する。時刻ｔ１４においてプリチャージ目標液圧がゼロになると、電子制御ユニットＥＣＵは、プリチャージ制御を終了する。ここで、実液圧がプリチャージ目標液圧を上回るタイミングではマスタシリンダ液圧Ｐｍとホイールシリンダ液圧Ｐｗ**とは略同一とみなせるため、電子制御ユニットＥＣＵは、マスタシリンダ液圧センサ４４の検出値に基づいてプリチャージ目標液圧の漸減を開始し得る。 When the actual hydraulic pressure exceeds the precharge target hydraulic pressure, the electronic control unit ECU determines that the precharge control is no longer necessary, and gradually decreases the precharge target hydraulic pressure. When the precharge target hydraulic pressure becomes zero at time t14, the electronic control unit ECU ends the precharge control. Here, since the master cylinder hydraulic pressure Pm and the wheel cylinder hydraulic pressure Pw ** can be regarded as substantially the same at the timing when the actual hydraulic pressure exceeds the precharge target hydraulic pressure, the electronic control unit ECU Based on the detected value, the precharge target hydraulic pressure can be gradually decreased.
　このように、本実施形態によれば、フェード状態にある場合に、ドライバーがブレーキペダルＢＰの操作を開始するタイミングｔ１３より前にアクセル開度の減少勾配に応じて調整されたプリチャージ目標液圧が設定される。ブレーキペダルＢＰが操作されていないときリザーバＲＳと圧力室１３ａ、１３ｂとは連通しているため、リザーバＲＳからブレーキ液を吸引することができ、マスタシリンダＭＣの圧力室内のブレーキ液の消費量を低減することができる。そのため、マスタシリンダの大型化を抑制することができる。さらに、ブレーキペダルＢＰの操作開始のタイミングｔ１３において、プリチャージ目標液圧が所定量かさ上げされる。ブレーキペダルＢＰの操作が開始されても、連通ポート１２ａ、１２ｂが遮断される位置まで各ピストンが前進するまでの間は、リザーバＲＳからブレーキ液を吸引することができる。そのため、上記と同様の効果が得られる他、実際にホイールシリンダ液圧Ｐｗ**の加圧が必要な場面での応答性を向上することができる。 Thus, according to the present embodiment, the precharge target hydraulic pressure adjusted according to the decreasing gradient of the accelerator opening before the timing t13 when the driver starts the operation of the brake pedal BP when in the fade state. Is set. When the brake pedal BP is not operated, the reservoir RS and the pressure chambers 13a and 13b communicate with each other, so that the brake fluid can be sucked from the reservoir RS, and the consumption amount of the brake fluid in the pressure chamber of the master cylinder MC can be reduced. Can be reduced. Therefore, the master cylinder can be prevented from being enlarged. Further, the precharge target hydraulic pressure is raised by a predetermined amount at the timing t13 when the operation of the brake pedal BP is started. Even when the operation of the brake pedal BP is started, the brake fluid can be sucked from the reservoir RS until each piston moves forward to a position where the communication ports 12a and 12b are blocked. Therefore, in addition to the same effects as described above, it is possible to improve the responsiveness in a scene where the wheel cylinder hydraulic pressure Pw ** is actually required.
　図６は、ドライバーがブレーキペダル操作へと移行しない場合の動作を示している。時刻ｔ２１から時刻ｔ２２までの期間は、図５の時刻ｔ１１から時刻ｔ１２までの期間と同様である。図６ではその後ブレーキペダルストロークが上昇しない。電子制御ユニットＥＣＵは、ブレーキペダルストロークの上昇がないまま、プリチャージ制御を開始した時刻ｔ２１、或いはプリチャージ目標液圧を急増した時刻ｔ２２からの経過時間（プリチャージ実行時間）が所定時間を経過した場合、プリチャージ目標液圧を漸減し、プリチャージ制御を終了する（時刻ｔ２３～ｔ２４）。 FIG. 6 shows the operation when the driver does not shift to the brake pedal operation. The period from time t21 to time t22 is the same as the period from time t11 to time t12 in FIG. In FIG. 6, the brake pedal stroke does not increase thereafter. In the electronic control unit ECU, the elapsed time (precharge execution time) from the time t21 when the precharge control is started or the time t22 when the precharge target hydraulic pressure is suddenly increased passes the predetermined time without increasing the brake pedal stroke. In this case, the precharge target hydraulic pressure is gradually decreased, and the precharge control is finished (time t23 to t24).
　図７は、ドライバーがアクセルペダル操作量を再び増加した場合の動作を示している。時刻ｔ３１から時刻ｔ３２にかけてはアクセル開度の減少勾配に応じて調整されたプリチャージ目標液圧が設定されるが、時刻ｔ３２以降アクセル開度が再び増加し始める。アクセル開度の増加に基づいて、電子制御ユニットＥＣＵは、ドライバーにアクセルペダル操作からブレーキペダル操作へと移行する兆候は見られないと判断し、プリチャージ目標液圧を漸減し、プリチャージ制御を終了する（時刻ｔ３２～ｔ３３）。 FIG. 7 shows the operation when the driver increases the accelerator pedal operation amount again. From time t31 to time t32, the precharge target hydraulic pressure adjusted according to the decreasing gradient of the accelerator opening is set, but after time t32, the accelerator opening starts to increase again. Based on the increase in accelerator opening, the electronic control unit ECU determines that the driver has no sign of shifting from the accelerator pedal operation to the brake pedal operation, gradually decreases the precharge target hydraulic pressure, and performs the precharge control. The process ends (time t32 to t33).
　以上説明したように、本実施形態によれば、フェード状態においてドライバーがブレーキペダルＢＰを操作する前にリザーバＲＳからブレーキ液を吸引することで、マスタシリンダＭＣの圧力室内のブレーキ液の消費量を低減することができる。ブレーキ液の消費量が多くなるホイールシリンダ液圧Ｐｗ**の低圧領域を、液圧ユニットＨＵによるプリチャージでカバーすることで、マスタシリンダの大型化を抑制することができる。また、パッド温度に関連する温度関連値に基づいてフェード状態を判定し、予めホイールシリンダＷ**にブレーキ液を供給することで、実際に減速度が不足することを回避することができ、フェード時の加圧応答性を向上することができる。また、アクセル開度及びブレーキペダルストロークに応じてプリチャージ目標液圧を調整することで、必要な場面で必要な大きさのホイールシリンダ液圧Ｐｗ**が得られる。 As described above, according to the present embodiment, the brake fluid consumption in the pressure chamber of the master cylinder MC is reduced by sucking the brake fluid from the reservoir RS before the driver operates the brake pedal BP in the fade state. Can be reduced. By covering the low pressure region of the wheel cylinder hydraulic pressure Pw **, in which the brake fluid consumption increases, with the precharge by the hydraulic pressure unit HU, it is possible to suppress an increase in the size of the master cylinder. Also, by determining the fade state based on the temperature-related value related to the pad temperature and supplying brake fluid to the wheel cylinder W ** in advance, it is possible to avoid the fact that the actual deceleration is insufficient. The pressure response at the time can be improved. Further, by adjusting the precharge target hydraulic pressure according to the accelerator opening and the brake pedal stroke, a wheel cylinder hydraulic pressure Pw ** having a required magnitude can be obtained in a required scene.
　本発明は上記の実施形態に限定されるものではない。例えば、図５において、実液圧がプリチャージ目標液圧を上回ると、電子制御ユニットＥＣＵは、プリチャージ目標液圧を漸減するようにしたが、これに限らない。ドライバー目標液圧がプリチャージ目標液圧を上回ると、実液圧もプリチャージ目標液圧を上回ることになるため、電子制御ユニットＥＣＵは、ドライバー目標液圧に基づいてプリチャージ目標液圧の漸減を開始し得る。 The present invention is not limited to the above embodiment. For example, in FIG. 5, when the actual hydraulic pressure exceeds the precharge target hydraulic pressure, the electronic control unit ECU gradually decreases the precharge target hydraulic pressure, but this is not a limitation. When the driver target hydraulic pressure exceeds the precharge target hydraulic pressure, the actual hydraulic pressure also exceeds the precharge target hydraulic pressure, so the electronic control unit ECU gradually decreases the precharge target hydraulic pressure based on the driver target hydraulic pressure. Can start.
　また、図６において、電子制御ユニットＥＣＵは、ブレーキペダルストロークの上昇がないままプリチャージ実行時間が所定時間を経過した場合、プリチャージ目標液圧を漸減するようにしたが、これに限らない。例えば、車両速度が低速になれば、高速の場合と比較して高い加圧応答性は必要とされない。そのため、車両速度が所定速度より低くなったことに基づいて、プリチャージ目標液圧を漸減するようにしてもよい。車両速度がさらに低い場合はプリチャージの実行を即時に終了する、又は、実行しないようにしてもよい。 In FIG. 6, the electronic control unit ECU gradually decreases the precharge target hydraulic pressure when the precharge execution time elapses a predetermined time without increasing the brake pedal stroke, but the present invention is not limited to this. For example, when the vehicle speed is low, high pressurization response is not required as compared with a high speed. Therefore, the precharge target hydraulic pressure may be gradually decreased based on the fact that the vehicle speed has become lower than the predetermined speed. When the vehicle speed is lower, the precharge may be immediately terminated or may not be performed.
　さらに、プリチャージ制御のキャンセルは、図７で説明したアクセル開度の増加以外にも、アクセル開度の増加量に基づいてキャンセルしてもよいし、エンジンブレーキや回生ブレーキによる制動力の大きさに基づいてキャンセルしてもよい。 Furthermore, the precharge control may be canceled based on the amount of increase in the accelerator opening, in addition to the increase in the accelerator opening described with reference to FIG. You may cancel based on.
　図１ではホイールシリンダ液圧を測定するセンサを有しない構成としたが、１つ又は複数のホイールシリンダ液圧センサを備えてもよい。ホイールシリンダ液圧センサの測定値に基づいて、より精確に液圧を調整し得る。 Although FIG. 1 does not include a sensor for measuring wheel cylinder hydraulic pressure, one or a plurality of wheel cylinder hydraulic pressure sensors may be provided. The hydraulic pressure can be adjusted more accurately based on the measured value of the wheel cylinder hydraulic pressure sensor.
　また、上記の実施形態では、４輪全てにプリチャージを実行するものを説明したが、これに限らない。２系統の液圧回路のうち１系統だけにプリチャージを実行してもよい。例えば、リニア電磁弁ＰＣ１、ＰＣ２のうち左右前輪ＦＲ、ＦＬに係わる系統のリニア電磁弁ＰＣ１のみをプリチャージ目標液圧に応じて制御することで、左右後輪ＲＲ、ＲＬに比べて制動効果の高い左右前輪ＦＲ、ＦＬだけにプリチャージを実行し得る。 In the above embodiment, the precharge is performed on all four wheels. However, the present invention is not limited to this. Precharging may be performed on only one of the two hydraulic circuits. For example, by controlling only the linear solenoid valve PC1 of the system related to the left and right front wheels FR and FL among the linear solenoid valves PC1 and PC2 according to the precharge target hydraulic pressure, the braking effect is improved as compared with the left and right rear wheels RR and RL. Only the high left and right front wheels FR and FL can be precharged.
　プリチャージはドライバーがブレーキペダルＢＰを所定量以上操作する前に予めホイールシリンダＷ**にブレーキ液を供給するため、減速度の出方によってはドライバーに違和感を与えることにもなる。プリチャージの実行を１系統だけにすることで、減速を適切に抑制し得る。前後２系統の両方でプリチャージを実行する場合、モータＭＴの負荷が大きい分、モータＭＴの回転数の低下が起こり得る。これに対して、プリチャージによる加圧を１系統だけにすることでモータＭＴの負荷が減るため、昇圧応答性を高めることができる。 Precharge is because the brake fluid is supplied to the wheel cylinder W ** in advance before the driver operates the brake pedal BP more than a predetermined amount, so that the driver may feel uncomfortable depending on how the deceleration is applied. Deceleration can be appropriately suppressed by executing only one system for precharging. When precharging is performed in both the front and rear systems, the rotational speed of the motor MT may decrease due to the large load on the motor MT. On the other hand, since the load of the motor MT is reduced by using only one system of pressurization by precharging, the boosting response can be improved.
　一般に、左右前輪ＦＲ、ＦＬと比べて左右後輪ＲＲ、ＲＬのホイールシリンダＷ**の消費液量の方が小さい。そこで、左右後輪ＲＲ、ＲＬに係わる系統の液量をまかなうことができるようにマスタシリンダＭＣを構成する。そして、より消費液量の多い左右前輪ＦＲ、ＦＬに係わる系統側だけプリチャージを実行して、不足する液量を補うように車両用制動装置を構成し得る。この構成によれば、マスタシリンダＭＣの体格は、左右後輪ＲＲ、ＲＬに係わる系統の液量を確保することができる大きさ（左右前輪ＦＲ、ＦＬに係わる系統についてはボトミングする大きさ）で済むため、マスタシリンダＭＣを小さくすることができる。 Generally, the liquid consumption of the wheel cylinders W ** of the left and right rear wheels RR and RL is smaller than that of the left and right front wheels FR and FL. Therefore, the master cylinder MC is configured so that the amount of fluid in the system related to the left and right rear wheels RR and RL can be covered. The vehicular braking device can be configured so as to compensate for the insufficient amount of liquid by executing precharge only on the system side related to the left and right front wheels FR, FL with a larger amount of liquid consumption. According to this configuration, the physique of the master cylinder MC is large enough to secure the liquid volume of the system related to the left and right rear wheels RR and RL (the size of bottoming for the system related to the left and right front wheels FR and FL). Therefore, the master cylinder MC can be reduced.
　逆に、前後２系統の液圧回路のうち左右後輪ＲＲ、ＲＬに係わる系統側だけプリチャージを実行するようにしてもよい。一般に、左右前輪ＦＲ、ＦＬと左右後輪ＲＲ、ＲＬとでは、左右後輪ＲＲ、ＲＬのブレーキの方が車両の減速度が発生し難い。そのため、左右後輪ＲＲ、ＲＬに係わる系統側だけプリチャージを実行することで、ドライバーにとって違和感のない自然なブレーキフィーリングとなり得る。 Conversely, precharging may be executed only on the system side related to the left and right rear wheels RR and RL in the two hydraulic systems of the front and rear systems. In general, between the left and right front wheels FR and FL and the left and right rear wheels RR and RL, the braking of the left and right rear wheels RR and RL is less likely to cause deceleration of the vehicle. Therefore, by executing precharge only on the system side related to the left and right rear wheels RR and RL, a natural brake feeling that does not cause a sense of incongruity to the driver can be obtained.

Claims (5)

  1. 　ブレーキ液を貯留するリザーバと、
    　ブレーキペダルの操作量が所定量以上になると圧力室と前記リザーバとを連通するポートが遮断されて前記ブレーキペダルの操作量に応じた液圧を発生するマスタシリンダと、
    　前記マスタシリンダとホイールシリンダとの間に設けられ、前記ホイールシリンダの液圧を調整する液圧ユニットと、
    　前記液圧ユニットを制御する電子制御ユニットと、を備え、
    　前記電子制御ユニットは、
    　車輪に固定された回転部材に前記ホイールシリンダの液圧によって押圧される摩擦部材の温度に関連する温度関連値に基づいて、前記摩擦部材がフェード状態にあるか否かを判定し、
    　前記フェード状態にあると判定した場合、前記ポートが前記圧力室と前記リザーバとを連通している期間に前記ポートを介して前記リザーバから前記ブレーキ液を吸引し、前記ホイールシリンダへ供給するプリチャージを実行するように前記液圧ユニットを制御するように構成された、車両用制動装置。     A reservoir for storing brake fluid;
    A master cylinder that generates a hydraulic pressure corresponding to the amount of operation of the brake pedal by blocking a port that communicates the pressure chamber and the reservoir when the amount of operation of the brake pedal exceeds a predetermined amount;
    A hydraulic unit provided between the master cylinder and the wheel cylinder for adjusting the hydraulic pressure of the wheel cylinder;
    An electronic control unit for controlling the hydraulic unit,
    The electronic control unit is
    Determining whether the friction member is in a fade state based on a temperature-related value related to the temperature of the friction member pressed by the hydraulic pressure of the wheel cylinder to the rotating member fixed to the wheel;
    When it is determined that the state is in the fade state, a precharge is performed in which the brake fluid is sucked from the reservoir through the port and supplied to the wheel cylinder during a period in which the port communicates the pressure chamber and the reservoir. A vehicular braking device configured to control the hydraulic unit to perform
  2. 　請求項１に記載の車両用制動装置において、
    　前記車両は、左右前輪に係わる前輪系統と左右後輪に係わる後輪系統の２系統の液圧回路を備え、
    　前記電子制御ユニットは、
    　前記２系統の液圧回路のうち前記前輪系統又は前記後輪系統の何れか一方にだけ前記プリチャージを実行するように前記液圧ユニットを制御するように構成された、車両用制動装置。     The vehicle braking device according to claim 1,
    The vehicle includes two hydraulic circuits, a front wheel system related to left and right front wheels and a rear wheel system related to left and right rear wheels,
    The electronic control unit is
    A vehicular braking apparatus configured to control the hydraulic unit so as to execute the precharge only on either the front wheel system or the rear wheel system of the two systems of hydraulic circuits.
  3. 　請求項１又は２に記載の車両用制動装置において、
    　前記電子制御ユニットは、
    　前記温度関連値に基づいて、前記プリチャージ実行時の前記ホイールシリンダの液圧の目標値を演算するように構成された、車両用制動装置。     The vehicle braking device according to claim 1 or 2,
    The electronic control unit is
    A vehicle braking device configured to calculate a target value of a hydraulic pressure of the wheel cylinder at the time of executing the precharge based on the temperature related value.
  4. 　請求項３に記載の車両用制動装置において、
    　前記電子制御ユニットは、
    　アクセルペダル操作量の減少速度が大きいほど、又は、ブレーキペダル操作量の増加速度が大きいほど、前記目標値を大きな値に調整するように構成された、車両用制動装置。     The vehicle braking device according to claim 3,
    The electronic control unit is
    A vehicular braking apparatus configured to adjust the target value to a larger value as a decrease speed of an accelerator pedal operation amount is larger or as an increase speed of a brake pedal operation amount is larger.
  5. 　請求項３又は４に記載の車両用制動装置において、
    　前記電子制御ユニットは、
    　前記プリチャージ実行時に前記車両のドライバーの操作態様に応じて前記目標値の漸減を開始し、前記目標値がゼロになると前記プリチャージの実行を終了するように構成された、車両用制動装置。     The vehicle braking device according to claim 3 or 4,
    The electronic control unit is
    A vehicular braking device configured to start gradually decreasing the target value in accordance with an operation mode of the driver of the vehicle at the time of executing the precharge, and end the execution of the precharge when the target value becomes zero.
PCT/JP2017/012733 2016-03-30 2017-03-28 Braking device for vehicle WO2017170596A1 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
DE112017001749.1T DE112017001749T5 (en) 2016-03-30 2017-03-28 BRAKING DEVICE FOR VEHICLE
CN201780020959.3A CN109070853B (en) 2016-03-30 2017-03-28 Vehicle brake device
US16/086,891 US11364890B2 (en) 2016-03-30 2017-03-28 Braking device for vehicle

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JP2016126462A JP6623952B2 (en) 2016-03-30 2016-06-27 Vehicle braking system

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WO2020027068A1 (en) * 2018-07-30 2020-02-06 株式会社アドヴィックス Brake control device
CN112498324A (en) * 2020-12-07 2021-03-16 潍柴动力股份有限公司 Method and device for determining vehicle braking state

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JP2001026263A (en) * 1999-07-13 2001-01-30 Nissan Motor Co Ltd Brake liquid pressure control device
JP2015136993A (en) * 2014-01-22 2015-07-30 株式会社アドヴィックス Vehicle brake device

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JP2001026263A (en) * 1999-07-13 2001-01-30 Nissan Motor Co Ltd Brake liquid pressure control device
JP2015136993A (en) * 2014-01-22 2015-07-30 株式会社アドヴィックス Vehicle brake device

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020027068A1 (en) * 2018-07-30 2020-02-06 株式会社アドヴィックス Brake control device
CN112498324A (en) * 2020-12-07 2021-03-16 潍柴动力股份有限公司 Method and device for determining vehicle braking state

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