JP2011042330A - Hydraulic pressure control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic pressure control device capable of achieving the brake operation having good brake feeling and less sense of incongruity. <P>SOLUTION: In the hydraulic pressure control device, a check valve with its valve opening pressure being substantially zero is connected to a second flow passage 16b provided parallel to a first flow passage 16a so as to bypass a mechanical booster valve 56, and transmits the pressure of a master cylinder to a wheel cylinder side when the pressure on the master cylinder side is higher than that of the wheel cylinder side, and suppresses any reverse flow of brake fluid on the wheel cylinder side to the master cylinder 14. A cut valve is provided on the downstream side of the mechanical booster valve 56 and the check valve 60. An ECU 90 closes the cut valve when detecting the operation of a brake pedal 12 under the predetermined condition, and thereafter, the ECU 90 opens a right master cut valve 22FR when the liquid pressure generated in the master cylinder 14 reaches the target liquid pressure set to be higher than the liquid pressure when the opened check valve 60 is closed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hydraulic pressure control device used for controlling hydraulic pressure of a hydraulic pressure circuit.

  2. Description of the Related Art Conventionally, a vehicle fluid that applies a braking force to a vehicle wheel by generating a hydraulic pressure in the hydraulic circuit according to the operating force of a brake pedal and supplying the hydraulic pressure in the hydraulic circuit to a wheel cylinder. Pressure brake devices are known. Such a hydraulic brake device is provided with an electromagnetic valve such as a pressure increasing valve or a pressure reducing valve in front of the wheel cylinder. By supplying and closing these electromagnetic valves, hydraulic fluid is supplied to and discharged from the wheel cylinder. The hydraulic pressure is controlled by adjusting the amount, and an appropriate braking force is applied to each wheel.

  Further, a hydraulic brake device including a master cylinder and a high pressure source is known as a hydraulic pressure source that generates a brake hydraulic pressure. When such a hydraulic brake device functions normally, the master cylinder and the wheel cylinder are disconnected from each other, and control is performed to increase the wheel cylinder pressure using the high pressure source as the hydraulic pressure source. In the above control, the wheel cylinder pressure is controlled to a hydraulic pressure having a predetermined boost ratio with respect to the master cylinder pressure.

  On the other hand, when a failure is recognized in the system, such a hydraulic brake device executes control for increasing the wheel cylinder pressure by connecting the master cylinder and the wheel cylinder and using the master cylinder as a hydraulic pressure source. According to the above control, the wheel cylinder pressure can be controlled to be equal to the master cylinder pressure. Therefore, according to the above-described hydraulic brake device, even if a failure occurs in the system, it is possible to generate at least a wheel cylinder pressure equal to the master cylinder pressure.

  However, in the above-described hydraulic brake device, when a failure is recognized in the system, even if the high pressure source is normal, the brake hydraulic pressure source is always changed from the high pressure source to the master cylinder. Therefore, a high-pressure source that can easily increase the wheel cylinder pressure cannot be used effectively, and there is still room for improvement in this respect.

  On the other hand, Patent Literature 1 discloses a hydraulic brake device that effectively uses a high-pressure source as a hydraulic pressure source when a failure is recognized in the system. This hydraulic brake device is provided with a pump hydraulic pressure passage that directly transmits the hydraulic pressure of a high-pressure source such as an accumulator to the wheel cylinder without a linear control valve when a failure is recognized in the system. The wheel cylinder pressure using the high pressure source as the hydraulic pressure source can be controlled by the mechanical pressure increasing valve provided at the junction of the pump hydraulic pressure passage and the front hydraulic pressure passage.

JP-A-11-48955

  As described above, the hydraulic brake device described in Patent Document 1 can effectively use a high-pressure source as a hydraulic pressure source when a failure is recognized in the system. However, in the above-described mechanical pressure increasing valve, when the pressure acting on the wheel cylinder is switched from the static pressure generated by the master cylinder to the servo pressure by the high pressure source, a dead zone is temporarily generated for the brake operation.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a hydraulic pressure control device that contributes to the realization of good brake feeling.

  In order to solve the above problems, a hydraulic pressure control device according to an aspect of the present invention includes a manual hydraulic pressure source that pressurizes a stored hydraulic fluid in accordance with an operation amount of a brake operation member by a driver, and a driver's brake. A hydraulic power source capable of accumulating with hydraulic fluid using power independent from the operation, and a braking force is applied to the wheel by receiving hydraulic fluid from at least one of the manual hydraulic pressure source and the hydraulic power source. A wheel hydraulic cylinder, a manual hydraulic pressure transmission path configured to connect the manual hydraulic pressure source and the wheel cylinder, and to supply hydraulic fluid from the manual hydraulic pressure source to the wheel cylinder; Power hydraulic pressure transmission configured to connect the power hydraulic pressure source and the wheel cylinder so that hydraulic fluid can be supplied from the power hydraulic pressure source to the wheel cylinder. And a first flow path of the manual hydraulic pressure transmission path, and in order to generate a hydraulic pressure of a predetermined pressure increasing ratio with respect to the hydraulic pressure generated by the manual hydraulic pressure source, A pressure increasing mechanism capable of introducing hydraulic fluid from the hydraulic pressure source to the wheel cylinder side, and a manual hydraulic pressure connected to a second flow path provided in parallel with the first flow path so as to bypass the pressure increasing mechanism. When the source side is higher than the wheel cylinder side, the pressure on the manual hydraulic pressure source side is transmitted to the wheel cylinder side and the hydraulic fluid on the wheel cylinder side is prevented from flowing back to the manual hydraulic pressure source side. Control valve for controlling the supply of hydraulic fluid from the pressure-increasing mechanism or the check valve to the wheel cylinder, which is provided downstream of the pressure-increasing mechanism and the check valve. , And a control unit for controlling the opening and closing of the control valve. The control unit closes the control valve when detecting an operation of the brake operation member under a predetermined condition, and then the hydraulic pressure generated by the manual hydraulic pressure source is opened. When the target hydraulic pressure set higher than the hydraulic pressure when the check valve is closed is reached, the control valve is opened.

  According to this aspect, in the pressure increasing mechanism, for example, even if the communication between the power hydraulic pressure source, the manual hydraulic pressure source, and the wheel cylinder is temporarily interrupted, the hydraulic pressure of the manual hydraulic pressure source Can be directly transmitted to the wheel cylinder via the second flow path without using the pressure increasing mechanism. At this time, since the second flow path is provided with a check valve having substantially zero valve opening pressure, the check valve is opened only if a differential pressure is generated between the manual hydraulic pressure source and the wheel cylinder. I speak. In other words, the pressure increases from the state in which the hydraulic pressure in the manual hydraulic pressure source is directly transmitted to the wheel cylinder until the hydraulic pressure at the predetermined pressure increase ratio is generated in the wheel cylinder with respect to the hydraulic pressure in the manual hydraulic pressure source. Even if transmission of hydraulic pressure from the manual hydraulic pressure source to the wheel cylinder via the pressure mechanism is temporarily interrupted, the hydraulic pressure of the manual hydraulic pressure source is adjusted to the wheel via the second flow path. It can be transmitted to the cylinder. As a result, the occurrence of a so-called dead zone, in which the change in pressure of the wheel cylinder does not correspond to the change in pressure in the manual hydraulic pressure source, is suppressed, and the brake feeling is improved.

  On the other hand, when a hydraulic pressure with a predetermined pressure increasing ratio relative to the hydraulic pressure of the manual hydraulic pressure source starts to be generated in the wheel cylinder by the pressure increasing mechanism, the pressure on the wheel cylinder side of the check valve becomes larger than that on the manual hydraulic pressure source side. Therefore, the check valve is closed. However, at the initial stage when the check valve starts to close, there is almost no differential pressure on both sides of the check valve. For this reason, the valve closing operation of the check valve becomes unstable, and this may cause vibration of the check valve itself and fluctuation of the hydraulic pressure in the vicinity of the check valve. Such a phenomenon also contributes to the transmission of the oil hammer to the manual hydraulic pressure source side, and also causes the driver to feel uncomfortable with the brake operation.

  Therefore, for example, when the operation of the brake operation member is detected under a predetermined condition where such an oil hammer may occur, the hydraulic pressure between the pressure increase mechanism and the wheel cylinder is closed by closing the control valve. Block transmission. As a result, the downstream path of the pressure increasing mechanism becomes a substantially rigid body, and the hydraulic pressure on the downstream side of the pressure increasing mechanism increased by using the hydraulic pressure of the power hydraulic pressure source rises more smoothly. The check valve that was open closes. Thereafter, the control unit does not open the control valve immediately after the check valve is closed, but opens the control valve after the hydraulic pressure generated by the manual hydraulic pressure source rises to some extent. Specifically, the control valve is opened when the hydraulic pressure of the manual hydraulic pressure source reaches a target hydraulic pressure set higher than the hydraulic pressure of the manual hydraulic pressure source when the check valve is closed. . Thereby, when the control valve is opened, a certain amount of differential pressure is generated on the upstream side and the downstream side of the check valve. For this reason, it is also possible to prevent the check valve from becoming unstable due to pressure fluctuation caused by the hydraulic fluid that has been boosted by the pressure boosting mechanism flowing out to the wheel cylinder side.

  The pressure increasing mechanism includes a pressurizing chamber that receives supply of hydraulic pressure from a master cylinder, a moving member that is biased in one direction by the hydraulic pressure in the pressurizing chamber, and a liquid that biases the moving member in the other direction. A pressure regulating chamber for storing pressure, and the power hydraulic pressure source and the pressure regulating chamber are in communication with each other when the moving member is displaced beyond the predetermined distance in the one direction, and the moving member is in the other direction. And a communication control mechanism that shuts off the power hydraulic pressure source and the pressure regulating chamber when displaced beyond a predetermined distance. The moving member may be configured such that the ratio of the area of the end surface on the pressurizing chamber side to the area of the end surface on the pressure regulating chamber side is the same as the pressure increasing ratio. Thereby, a desired pressure increase ratio can be realized with a simple configuration.

  An orifice may be provided between the power hydraulic pressure source and the pressure increasing mechanism. As a result, the rapid transmission of hydraulic pressure from the power hydraulic pressure source to the pressure increasing mechanism is suppressed, and as a result, the rapid fluctuation of the hydraulic pressure generated on the wheel cylinder side of the pressure increasing mechanism is suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the hydraulic-pressure control apparatus which contributes to implementation | achievement of a favorable brake feeling and a brake operation with little discomfort can be provided.

1 is a system diagram of a brake control device according to an embodiment of the present invention. It is a systematic diagram which shows the outline of the hydraulic control apparatus which concerns on this Embodiment. It is a figure which shows the relationship between the master cylinder pressure at the time of master pressurization, and a wheel cylinder pressure. It is a figure which shows the relationship between the master cylinder pressure at the time of the master pressurization of the hydraulic pressure control apparatus which concerns on this Embodiment, and a wheel cylinder pressure. It is a figure which shows the flowchart of the initial check which concerns on this Embodiment. It is a systematic diagram which shows the outline of the hydraulic control apparatus which concerns on other embodiment. It is the figure which showed typically the required characteristic calculated | required by an orifice.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. The hydraulic pressure control device described in the following embodiments can be applied as long as it is a hydraulic pressure circuit that controls the hydraulic pressure. For example, it is suitable for use in a hydraulic pressure circuit of an electronically controlled brake system for a vehicle. is there. In the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate.

(Outline of brake control device)
FIG. 1 is a system diagram of a brake control device 10 according to an embodiment of the present invention. The brake control device 10 employs an electronically controlled brake system (ECB), and independently and optimally sets the four-wheel brakes of the vehicle according to the operation of the brake pedal 12 as a brake operation member by the driver.

The brake pedal 12 is connected to a master cylinder 14 that sends out brake fluid as hydraulic fluid in response to a depression operation by the driver. The master cylinder 14 has two hydraulic chambers therein. In these hydraulic pressure chambers, a master cylinder pressure P _{M / C} corresponding to the brake depression force is generated. The brake pedal 12 is provided with a stroke sensor 46 that detects the depression stroke.

  Further, a reservoir tank 26 is connected to the upper part of the master cylinder 14 to store brake fluid as hydraulic fluid. The hydraulic chamber of the master cylinder 14 and the reservoir tank 26 are in a conductive state when the depression of the brake pedal 12 is released. A stroke simulator 24 that creates a reaction force according to the operating force of the brake pedal 12 by the driver is connected to one output port of the master cylinder 14 via an electromagnetic valve 23.

  The stroke simulator 24 is a mechanism that applies a stroke according to the brake depression force to the brake pedal 12 when the brake pedal 12 is depressed. The electromagnetic valve 23 is a so-called normally closed linear valve that closes when no current is supplied, and is supplied with current when the driver depresses the brake pedal 12 and is opened.

  A brake hydraulic pressure control pipe 16 for the right front wheel is connected to one output port of the master cylinder 14. The brake hydraulic pressure control pipe 16 is connected to a right front wheel wheel cylinder 20FR that applies a braking force to the right front wheel. A brake hydraulic pressure control pipe 18 for the left front wheel is connected to the other output port of the master cylinder 14. The brake hydraulic control pipe 18 is connected to a left front wheel wheel cylinder 20FL that applies a braking force to the left front wheel.

  A right master cut valve 22FR is provided in the middle of the brake hydraulic control pipe 16, and a left master cut valve 22FL is provided in the middle of the brake hydraulic control pipe 18. Each of the right master cut valve 22FR and the left master cut valve 22FL is a so-called normally open type linear valve, which is closed in a state where electric current is supplied, and closes the master cylinder 14 and the right front wheel wheel cylinder 20FR or the left front wheel. The communication with the wheel cylinder 20FL is prevented. On the other hand, the right master cut valve 22FR and the left master cut valve 22FL are opened when current supply is reduced or stopped, and the master cylinder 14 communicates with the right front wheel wheel cylinder 20FR or the left front wheel wheel cylinder 20FL. Let Hereinafter, the right master cut valve 22FR and the left master cut valve 22FL are collectively referred to as a master valve 22 as necessary.

A right master pressure sensor 48FR for detecting the master cylinder pressure on the right front wheel side is provided in the middle of the brake hydraulic pressure control pipe 16. A left master pressure sensor 48FL that detects the master cylinder pressure on the left front wheel side is provided in the middle of the brake hydraulic pressure control pipe 18 for the left front wheel. The right master pressure sensor 48FR outputs a signal corresponding to the hydraulic pressure introduced into the brake hydraulic pressure control pipe 16, that is, the first master cylinder pressure P _{M / C.} The left master pressure sensor 48FL outputs a signal corresponding to the hydraulic pressure introduced into the brake hydraulic pressure control pipe 18, that is, the second master cylinder pressure PM _{/ C.} The output signal pMC of these master pressure sensors is supplied to the ECU 90. The ECU 90 detects the master cylinder pressure P _{M / C} based on the output signal pMC.

  In the brake control apparatus 10, when the brake pedal 12 is depressed by the driver, the stroke operation amount is detected by the stroke sensor 46, but the master cylinder pressure detected by the right master pressure sensor 48FR and the left master pressure sensor 48FL. Therefore, the depression force (depression force) of the brake pedal 12 can be obtained. The electronic control unit (hereinafter referred to as “ECU”) 90 monitors the master cylinder pressure from the detection results of the right master pressure sensor 48FR and the left master pressure sensor 48FL from the viewpoint of fail-safe in consideration of the failure of the stroke sensor 46 and the like. To do.

  One end of a hydraulic supply / discharge pipe 28 is connected to the reservoir tank 26. A suction port of a pump 34 driven by a motor 32 is connected to the other end of the hydraulic supply / discharge pipe 28. The discharge port of the pump 34 is connected to a high pressure pipe 30, and an accumulator 50 and a relief valve 53 are connected to the high pressure pipe 30. In the present embodiment, a reciprocating pump including two or more pistons (not shown) that are reciprocated by a motor 32 is employed as the pump 34. Further, an accumulator 50 that stores brake fluid at a high pressure is employed.

  The accumulator 50 stores the brake fluid whose pressure has been increased to, for example, about 14 to 22 MPa by the pump 34. Further, the valve outlet of the relief valve 53 is connected to the hydraulic supply / discharge pipe 28. When the pressure of the brake fluid in the accumulator 50 is abnormally increased to about 25 MPa, for example, the relief valve 53 is opened and the high pressure brake is opened. The fluid is returned to the hydraulic supply / discharge pipe 28. Further, the high-pressure pipe 30 is provided with an accumulator pressure sensor 51 that detects the outlet pressure of the accumulator 50, that is, the pressure of the brake fluid in the accumulator 50.

  The high pressure pipe 30 includes a right front wheel pressure increasing valve 40FR, a left front wheel pressure increasing valve 40FL, a right rear wheel pressure increasing valve 40RR, and a left rear wheel pressure increasing valve 40RL (hereinafter collectively referred to as “pressure increasing valve” as necessary. 40 ”), the right front wheel wheel cylinder 20FL, the left front wheel wheel cylinder 20FL, the right rear wheel wheel cylinder 20RR, and the left rear wheel wheel cylinder 20RL (hereinafter collectively referred to as necessary). (Referred to as “wheel cylinder 20”). Each of the pressure increasing valves 40 is a so-called normally closed linear valve (solenoid valve), which is closed when no current is supplied to open the wheel cylinder pressure without increasing the wheel cylinder pressure. Then, increase the wheel cylinder pressure.

  The right front wheel wheel cylinder 20FR to the right rear wheel wheel cylinder 20RR are respectively a right front wheel pressure reducing valve 42FR, a left front wheel pressure reducing valve 42FL, a right rear wheel pressure reducing valve 42RR, and a left rear wheel pressure reducing valve 42RL (hereinafter, These are collectively referred to as “reducing valve 42” as necessary.

  The right front wheel pressure reducing valve 42FR and the left front wheel pressure reducing valve 42FL are so-called normally-closed linear valves (solenoid valves). When the current is not supplied, the valve is closed and the wheel cylinder pressure is not reduced. When supplied, the valve opens to reduce the wheel cylinder pressure. On the other hand, the left rear wheel pressure reducing valve 42RL and the right rear wheel pressure reducing valve 42RR are so-called normally open linear valves (solenoid valves), which are closed when the current is supplied to reduce the wheel cylinder pressure. First, when the current supply is reduced or stopped, the valve is opened to reduce the wheel cylinder pressure.

  The right front wheel wheel cylinder 20FR, the left front wheel wheel cylinder 20FL, the right rear wheel wheel cylinder 20RR, and the hydraulic piping in the vicinity of the left rear wheel wheel cylinder 20RL respectively detect the hydraulic pressure of the corresponding wheel cylinder 20 respectively. Front wheel wheel cylinder pressure sensor 44FR, left front wheel wheel cylinder pressure sensor 44FL, right rear wheel wheel cylinder pressure sensor 44RR, and left rear wheel wheel cylinder pressure sensor 44RL (hereinafter collectively referred to as “ A wheel cylinder pressure sensor 44 ") is provided.

  The above-described master valve 22, pressure increasing valve 40, pressure reducing valve 42, pump 34, accumulator 50, master pressure sensor 48, wheel cylinder pressure sensor 44, accumulator pressure sensor 51 and the like constitute a hydraulic actuator 80. The operation of the hydraulic actuator 80 is controlled by the ECU 90.

  In addition to the above-described operation, the brake control device 10 according to the present embodiment effectively uses the accumulator 50 as a high-pressure source in order to generate a braking force even when a failure is recognized in the system. It is configured to be able to.

  Specifically, the brake control device 10 is provided with a pump hydraulic pressure passage 29 that directly transmits the hydraulic pressure of the accumulator 50 to the wheel cylinder 20 without passing through the pressure increasing valve 40 when a failure is recognized in the system. . The wheel cylinder pressure using the accumulator 50 as a hydraulic pressure source is controlled by the mechanical pressure increase valves 56 and 58 provided at the junction of the pump hydraulic pressure passage 29 and the brake hydraulic pressure control pipe 16 and the brake hydraulic pressure control pipe 18. It becomes possible.

  The brake hydraulic control pipe 16 communicates with the mechanical pressure increasing valve 56 and the check valve 60. The brake hydraulic pressure control pipe 16 is branched into two flow paths along the way. A mechanical pressure increasing valve 56 is provided in the first flow path 16a, and a check valve (check valve) 60 is provided in the second flow path 16b. It is connected. Further, the brake hydraulic pressure control pipe 18 communicates with the mechanical pressure increasing valve 58 and the check valve 62. The brake hydraulic pressure control pipe 18 is branched into two flow paths along the way, and a mechanical pressure increasing valve 58 is connected to the first flow path 18a, and a check valve 62 is connected to the second flow path 18b.

The mechanical pressure increasing valve 56 communicates with an atmospheric pressure passage 27 (not shown in FIG. 1, see FIG. 2), a right front hydraulic pressure passage 64, and one passage 29 a branched from the pump hydraulic pressure passage 29. The atmospheric pressure passage 27 is opened to the atmospheric pressure by communicating with the reservoir tank 26 via the hydraulic supply / discharge pipe 28. The hydraulic pressure generated by the mechanical pressure increasing valve 56 is discharged from the right front hydraulic pressure passage 64. Further, a high accumulator pressure P _ACC is supplied to one passage 29 a of the pump hydraulic pressure passage 29 via the check valve 31. The check valve 31 is a one-way valve that allows only a fluid flow from the accumulator 50 side to the mechanical pressure increasing valve 56 side.

The mechanical pressure increasing valve 58 communicates with the atmospheric pressure passage 27 (not shown in FIG. 1, see FIG. 2), the left front hydraulic pressure passage 66, and the other passage 29b branched from the pump hydraulic pressure passage 29. Yes. The atmospheric pressure passage 27 is opened to the atmospheric pressure by communicating with the reservoir tank 26 via the hydraulic supply / discharge pipe 28. From the left front hydraulic pressure passage 66, the hydraulic pressure generated by the mechanical pressure increasing valve 58 is discharged. A high accumulator pressure P _ACC is supplied to the other passage 29 b of the pump hydraulic pressure passage 29.

(Hydraulic pressure control device)
FIG. 2 is a system diagram showing an outline of the hydraulic control apparatus according to the present embodiment. The brake control device 10 according to the present embodiment functions for the first hydraulic pressure control device having the mechanical pressure increasing valve 56 that functions for the right front wheel wheel cylinder 20FR, and for the left front wheel wheel cylinder 20FL. And a second hydraulic pressure control device having a mechanical pressure increasing valve 58. Since the first hydraulic pressure control device and the second control mechanism have the same configuration, hereinafter, the first hydraulic pressure control device (hereinafter referred to as “hydraulic pressure control device”) acting on the right front wheel wheel cylinder 20FR. Will be described.

As shown in FIG. 2, the hydraulic pressure control device 200 includes a mechanical pressure increasing valve 56 and a check valve 60. The mechanical pressure increasing valve 56 is connected to the first flow path 16a between the master cylinder 14 and the right front wheel wheel cylinder 20FR. The mechanical pressure increasing valve 56 generates a wheel cylinder pressure P _{W / C} having a predetermined pressure increasing ratio in the right front wheel wheel cylinder 20FR with respect to the master cylinder pressure P _{M / C} generated in the master cylinder 14. Therefore, the mechanical pressure increasing valve 56 according to the present embodiment is configured such that brake fluid can be introduced from the accumulator 50 to the right front wheel wheel cylinder 20FR when pressure is increased.

  The check valve 60 is connected to a second flow path 16b provided between the master cylinder 14 and the wheel cylinder 20FR in parallel with the first flow path 16a. The check valve 60 transmits the pressure on the master cylinder side to the wheel cylinder side when the master cylinder side is higher in pressure than the wheel cylinder side, and suppresses the hydraulic fluid on the wheel cylinder side from flowing back to the master cylinder side. Specifically, the valve opening pressure of the check valve 60 according to the present embodiment is substantially zero. The check valve 60 opens according to an increase in the hydraulic pressure of the master cylinder 14 when the pressure is increased, supplies hydraulic fluid to the right front wheel wheel cylinder 20FR side, and closes according to an increase in the hydraulic pressure of the wheel cylinder. To do. Hereinafter, the configurations of the mechanical pressure increasing valve 56 and the check valve 60 will be described in detail.

(Mechanical booster valve)
The mechanical pressure increasing valve 56 includes a housing 68. The housing 68 has a master pressure introducing hole 70 communicating with the first flow path 16 a, a hydraulic pressure discharging hole 72 communicating with the right front hydraulic pressure path 64, and a high pressure introducing hole communicating with one of the passages 29 a of the pump hydraulic pressure path 29. 74 and an air introduction hole 76 communicating with the atmospheric pressure passage 27 are provided.

  A stepped piston 78 is disposed inside the housing 68. The stepped piston 78 is formed with a large diameter portion 82 having a large cross sectional area S and a small diameter portion 84 having a small cross sectional area s. A through hole 86 is formed inside the stepped piston 78. A needle valve 88 is disposed at the downstream end portion of the through hole 86 so as to be able to come into contact therewith. A valve seat 92 that functions as a valve seat of the needle valve 88 is provided inside the through hole 86. A first spring 94 is disposed between the needle valve 88 and the stepped piston 78. The first spring 94 generates an urging force in a direction for separating the needle valve 88 from the valve seat 92.

  Inside the housing 68, a ball valve 96, a second spring 98, and a third spring 100 are disposed. A valve seat 102 for the ball valve 96 is formed inside the housing 68. The second spring 98 biases the ball valve 96 toward the valve seat 102. The third spring 100 biases the stepped piston 78 toward the master pressure introduction hole 70 side. A through hole 104 that allows the needle valve 88 to pass therethrough is provided at the center of the valve seat 102.

  Inside the housing 68, the pressurizing chamber 106, the pressure regulating chamber 108, the high pressure chamber 110 and the drain chamber 112 are formed by the stepped piston 78 and the ball valve 96 described above. The pressurizing chamber 106 communicates with the master pressure introducing hole 70 and receives supply of hydraulic pressure from the master cylinder 14. The pressure regulating chamber 108 communicates with the hydraulic pressure discharge hole 72. The high pressure chamber 110 communicates with the high pressure introduction hole 74. Further, the drain chamber 112 communicates with the air introduction hole 76.

  A stopper 68 a is further formed inside the housing 68. The stopper 68 a is provided on the inner wall of the pressure regulating chamber 108 to restrict the displacement of the needle valve 88. That is, the right displacement end of the needle valve 88 in FIG. 2 is restricted to a position where the needle valve 88 contacts the stopper 68a.

  As described above, the hydraulic pressure control device 200 according to the present embodiment has the master cylinder 14 that pressurizes the stored hydraulic fluid in accordance with the amount of operation of the brake pedal 12 by the driver, and power that is independent from the driver's brake operation. An accumulator 50 capable of accumulating pressure using brake fluid, a wheel cylinder 20FR that receives a brake fluid from at least one of the master cylinder 14 and the accumulator 50, and applies braking force to the wheel, and the master cylinder 14 and the wheel cylinder 20FR. And the brake hydraulic control pipe 16 and the right front hydraulic pressure passage 64 configured to be able to supply brake fluid from the master cylinder 14 to the wheel cylinder FR, and the accumulator 50 and the wheel cylinder 20FR. And accumulator 50 A high pressure passage 114 configured to be able to supply brake fluid to the wheel cylinder 20FR and a first flow path 16a of the brake hydraulic pressure control pipe 16 is provided with respect to a hydraulic pressure generated in the master cylinder 14. In order to cause the wheel cylinder 20FR to generate a hydraulic pressure with the pressure increase ratio, a mechanical pressure increasing valve 56 capable of introducing hydraulic fluid from the accumulator 50 to the wheel cylinder 20FR side at the time of pressure increase and the mechanical pressure increasing valve 56 are bypassed. When the master cylinder 14 side is higher in pressure than the wheel cylinder 20FR side, the pressure on the master cylinder 14 side is transmitted to the wheel cylinder 20FR side and the wheel cylinder is connected to the second channel 16b provided in parallel with the first channel 16a. The brake fluid on the 20FR side is prevented from flowing back to the master cylinder 14 side, A check valve 60 having substantially zero valve pressure, a mechanical pressure increasing valve 56 and a check valve 60 are provided downstream of the check valve 60, and the brake fluid is supplied from the mechanical pressure increasing valve 56 or the check valve 60 to the wheel cylinder 20FR. A right master cut valve 22FR that controls the ECU, and an ECU 90 that controls opening and closing of the right master cut valve 22FR.

(Operation of hydraulic pressure control device)
Hereinafter, the operation of the hydraulic pressure control device 200 including the mechanical pressure increasing valve 56 and the check valve 60 will be described. The mechanical pressure increase valve 56 is maintained in the state shown in FIG. 2 when the master cylinder pressure P _{M / C} is not generated. When the brake operation is started under such circumstances, the brake fluid flows into the pressurizing chamber 106 from the master pressure introducing hole 70. The brake fluid flowing into the pressurizing chamber 106 reaches the pressure regulating chamber 108 through the through hole 86. For this reason, after the brake operation is started, the internal pressure of the pressurizing chamber 106 and the internal pressure of the pressure regulating chamber 108 both rise to the master cylinder pressure P _{M / C.}

When the master cylinder pressure P _{M / C} is generated in both the pressurizing chamber 106 and the pressure regulating chamber 108, the stepped piston 78 is expressed by F = S · P _{M / C} −s · P _{M / C} , and The urging force toward the pressure regulating chamber 108 acts. As a result, after the brake operation is started, the stepped piston 78 immediately starts to be displaced from the position shown in FIG. 2 toward the pressure regulating chamber 108 side.

  When the amount of displacement of the stepped piston 78 toward the pressure regulating chamber 108 reaches a predetermined amount, a state in which the needle valve 88 closes the through hole 86 is formed. When such a state is formed, the urging force F that has been applied to the stepped piston 78 starts to be transmitted to the ball valve 96 through the needle valve 88. For this reason, when the displacement of the stepped piston 78 reaches the predetermined amount, a state in which the ball valve 96 is separated from the valve seat 102 is formed thereafter.

When the ball valve 96 is separated from the valve seat 102, the high pressure chamber 110 and the pressure regulating chamber 108 become conductive. For this reason, when the ball valve 96 is opened, the internal pressure of the pressure regulating chamber 108 thereafter becomes higher than the master cylinder pressure PM _{/ C.} At this time, if the hydraulic pressure generated in the pressure regulating chamber 108 is Pc, the magnitude of the urging force acting on the stepped piston 78 can be expressed as F = S · P _{M / C} −s · Pc. The stepped piston 78 continues to be displaced in the direction in which the ball valve 96 is opened when the urging force F is a positive value.

When the hydraulic pressure Pc in the pressure regulating chamber 108 becomes a sufficiently large value, the urging force F acting on the stepped piston 78 becomes a negative value. When the urging force F becomes a negative value, the stepped piston 78 starts to be displaced in the direction in which the ball valve 96 is closed. When the ball valve 96 is seated on the valve seat 102, the increase in the internal pressure Pc in the pressure regulating chamber 108 is stopped. In the mechanical pressure increasing valve 56, the above operation is repeatedly executed after the brake operation is executed by the driver, whereby the internal pressure Pc of the pressure adjusting chamber 108 is Pc = (S / s) · P _{M / C.} It is controlled by the hydraulic pressure represented by The hydraulic pressure Pc generated in the pressure regulating chamber 108 is discharged from the hydraulic pressure discharge hole 72 to the right front hydraulic pressure passage 64. As described above, according to the mechanical pressure increasing valve 56, when a brake operation is executed by the driver, the liquid having a predetermined boost ratio (pressure increasing ratio) S / s with respect to the master cylinder pressure PM _{/ C.} The pressure Pc can be supplied to the right front hydraulic pressure passage 64.

  As described above, the mechanical pressure increasing valve 56 according to the present embodiment is urged to the left in FIG. 2 by the pressurizing chamber 106 that receives supply of the hydraulic pressure from the master cylinder 14 and the hydraulic pressure of the pressurizing chamber 106. The stepped piston 78, the pressure adjusting chamber 108 that stores the hydraulic pressure that urges the stepped piston 78 in the right direction in FIG. 2, and the stepped piston 78 are displaced in the left direction in FIG. 2 over a predetermined distance. If the accumulator 50 and the pressure regulating chamber 108 are in communication with each other, and the stepped piston 78 is displaced beyond the predetermined distance in the right direction in FIG. 2, the accumulator 50 and the pressure regulating chamber 108 are shut off. And a communication control mechanism. The stepped piston 78 is configured such that the ratio of the area S of the end surface of the large diameter portion 82 on the pressurizing chamber 106 side to the area s of the end surface of the small diameter portion 84 on the pressure regulating chamber 108 side is the same as the pressure increase ratio. Has been. As described above, the ratio of the area s of the small-diameter portion 84 on the pressure regulating chamber 108 side of the stepped piston 78 to the area S of the large-diameter portion 82 on the pressurizing chamber side is adjusted. A desired pressure increase ratio is realized with a simple configuration.

On the other hand, when the accumulator pressure P _ACC is not properly guided to the high pressure chamber 110, the force for urging the ball valve 96 toward the valve seat 102 is only the urging force of the second spring 98. Further, the master cylinder pressure P _{M / C} is transmitted to the wheel cylinder 20 without the brake fluid flowing back to the accumulator 50 by the check valve 31.

For this reason, when the internal pressure of the high pressure chamber 110 is not properly increased, the internal pressure of the pressure adjusting chamber 108 is always equal to the master cylinder pressure P _{M / C} during execution of the brake operation. Therefore, according to the mechanical pressure increasing valve 56, when the brake operation is executed under a situation where the internal pressure of the high pressure chamber 110 is not properly increased, the right front hydraulic pressure passage 64 and the right front hydraulic pressure passage 64 are connected to the master cylinder. A hydraulic pressure equal to the pressure P _{M / C} can be discharged. When the master cylinder pressure P _{M / C} is guided to the pressure regulating chamber 108 of the mechanical pressure increasing valve 56 as described above, the master cylinder pressure P _{M / C} is passed through the high pressure chamber 110 and the high pressure introduction hole 74. Then, it is also supplied to one passage 29 a of the pump hydraulic pressure passage 29.

  As described above, in the brake control device 10 provided with the hydraulic pressure control device 200 according to the present embodiment, the master cylinder 14 uses the brake fluid accumulated in the accumulator 50 or the like even when the brake system is abnormal. A hydraulic pressure having a predetermined pressure increasing ratio with respect to the hydraulic pressure can be generated in the wheel cylinder.

  By the way, in the mechanical pressure increasing valve 56 according to the present embodiment, as described above, when the displacement amount of the stepped piston 78 toward the pressure regulating chamber 108 reaches a predetermined amount, the needle valve 88 closes the through hole 86. A state is formed. After such a state is formed, the pressure adjusting chamber 108 is in a period from when the stepped piston 78 is further displaced by the urging force F until the ball valve 96 is separated from the valve seat 102 via the needle valve 88. The brake fluid will not flow into. Therefore, when only the mechanical pressure increasing valve 56 is connected to the brake hydraulic control pipe 16, a time lag occurs before the increase in the master cylinder pressure is transmitted to the wheel cylinder.

  However, the hydraulic pressure control apparatus 200 according to the present embodiment is a case where the communication between the accumulator 50, the master cylinder 14, and the wheel cylinder 20FR is temporarily interrupted in the mechanical pressure increasing valve 56. The hydraulic pressure in the master cylinder 14 can be directly transmitted to the wheel cylinder 20FR via the second flow path 16b without passing through the mechanical pressure increasing valve 56. At that time, the second flow path 16b is provided with a check valve whose valve opening pressure is substantially zero. Therefore, if the differential pressure is generated between the master cylinder 14 and the wheel cylinder 20FR, it can be easily checked. The valve 60 opens.

  That is, between the state where the hydraulic pressure in the master cylinder 14 is directly transmitted to the wheel cylinder 20FR and the time when the hydraulic pressure with a predetermined pressure increase ratio is generated in the wheel cylinder 20FR with respect to the hydraulic pressure in the master cylinder 14, the machine Even when the transmission of the hydraulic pressure from the master cylinder 14 to the wheel cylinder 20FR via the pressure increasing valve 56 is temporarily interrupted, the hydraulic pressure of the master cylinder 14 via the second flow path 16b. Can be transmitted to the wheel cylinder 20FR. As a result, the occurrence of a so-called dead zone in which the change in pressure of the wheel cylinder 20FR does not correspond to the change in pressure in the master cylinder 14 is suppressed, and the brake feeling is improved.

After that, when the stepped piston 78 is further displaced by the operation of the brake pedal and the ball valve 96 is separated from the valve seat 102, the high pressure chamber 110 and the pressure regulating chamber 108 are brought into conduction, and the internal pressure of the pressure regulating chamber 108 becomes the master pressure. Higher than the cylinder pressure P _{M / C.} For this reason, the brake fluid attempts to flow back through the second flow path 16b via the right front hydraulic pressure passage 64 between the pressure regulating chamber 108 and the wheel cylinder 20FR, but the check valve 60 is closed due to the differential pressure. Thus, the flow from the wheel cylinder 20FR to the master cylinder 14 is interrupted.

(Configuration and operation of brake control device)
In the brake control device 10 shown in FIG. 1, a right master cut valve 22FR is disposed in the right front hydraulic pressure passage 64, and a left master cut valve 22FL is disposed in the left front hydraulic pressure passage 66. The right master cut valve 22FR is a two-position electromagnetic valve that maintains a valve-open state in a normal state and is closed when a drive signal is supplied from the ECU 90. The right front hydraulic pressure passage 64 communicates with a wheel cylinder 20FR disposed on the right front wheel. In addition, the right front hydraulic pressure passage 64 communicates with a wheel cylinder pressure sensor 44FR that outputs a signal corresponding to the hydraulic pressure generated therein, that is, the wheel cylinder pressure P _{M / C} of the right front wheel. An output signal pFR from the wheel cylinder pressure sensor 44 is supplied to the ECU 90. The ECU 90 detects the wheel cylinder pressure P _{M / C} of the right front wheel based on the output signal pFR.

The left master cut valve 22FL is a two-position electromagnetic valve that maintains a valve-open state in a normal state and is closed when a drive signal is supplied from the ECU 90. The left front hydraulic pressure passage 66 communicates with a left front wheel wheel cylinder 20FL disposed on the right front wheel. The left front hydraulic pressure passage 66 communicates with a wheel cylinder pressure sensor 44FL that outputs a signal corresponding to the hydraulic pressure generated inside the left front hydraulic pressure passage 66, that is, the wheel cylinder pressure P _{M / C} of the left front wheel. The output signal pFR of the wheel cylinder pressure sensor 44FL is supplied to the ECU 90. The ECU 90 detects the wheel cylinder pressure P _{M / C} of the left front wheel based on the output signal pFR.

  The brake control device 10 includes a hydraulic supply / discharge pipe 28 that communicates with the reservoir tank 26. The atmospheric pressure passage 27 described above communicates with the reservoir tank 26 via a hydraulic supply / discharge pipe 28. The hydraulic supply / discharge pipe 28 communicates with the suction side of the pump 34 and the downstream side of the pressure reducing valve 42. The discharge side of the pump 34 communicates with the high pressure passage 114.

The above-described pump hydraulic pressure passage 29 communicates with the high pressure passage 114, and an accumulator cut valve 116 and a check valve 31 are disposed in the middle of the pump hydraulic pressure passage 29. The accumulator cut valve 116 is an on-off valve that appropriately controls the flow of fluid from the high-pressure passage 114 side to the pump hydraulic passage 29 side. When the internal pressure of the high pressure passage 114 does not rise properly, the internal pressure of the high pressure chamber 110 of the mechanical pressure increase valve 56 does not rise properly. Therefore, when such a situation is detected by a signal from the accumulator pressure sensor 51 or the like, the ECU 90 transmits a control signal to the accumulator cut valve 116 to close the valve. As a result, as described above, the master cylinder pressure P _{M / C} is guided to the pump hydraulic pressure passage 29 by executing the brake operation. By such an operation of the accumulator cut valve 116, the master cylinder pressure P _{M / C} guided to the pump hydraulic pressure passage 29 via the mechanical pressure increasing valve 56 is released to the high pressure passage 114 side under such a situation. Can be prevented.

The accumulator 50 communicates with the high pressure passage 114. The accumulator 50 can store the hydraulic pressure discharged from the pump 34 as an accumulator pressure P _ACC therein. An accumulator pressure sensor 51 that outputs an electrical signal corresponding to the accumulator pressure P _ACC is disposed in the high-pressure passage 114. The output signal pACC of the accumulator pressure sensor 51 is supplied to the ECU 90. The ECU 90 detects the accumulator pressure P _ACC based on the output signal pACC.

  A relief valve 53 is disposed between the high pressure passage 114 and the hydraulic supply / discharge pipe 28. When the hydraulic pressure on the high-pressure passage 114 side exceeds the predetermined valve opening pressure as compared with the hydraulic pressure on the hydraulic supply / exhaust tube 28 side, the relief valve 53 is hydraulically supplied / discharged from the high-pressure passage 114 side. This is a one-way valve that allows the flow of fluid toward the pipe 28 side. The high pressure passage 114 communicates with a right front wheel pressure increasing valve 40FR, a left front wheel pressure increasing valve 40FL, a right rear wheel pressure increasing valve 40RR, and a left rear wheel pressure increasing valve 40RL.

  The right front wheel pressure increasing valve 40FR also communicates with the right front hydraulic pressure passage 64. Further, the left front wheel pressure increasing valve 40FL communicates with the left front hydraulic pressure passage 66 as well. Each pressure increasing valve 40 is maintained in a closed state when no drive signal is supplied from the ECU 90. Further, each of the pressure increasing valves 40 receives a right front hydraulic pressure passage 64, a left front hydraulic pressure passage 66, a right rear hydraulic pressure passage 118, a left rear hydraulic pressure passage from the high pressure passage 114 side when a drive signal is supplied from the ECU 90. The brake fluid is caused to flow into 120 so that wheel cylinder pressure corresponding to the drive signal is generated.

  The right front hydraulic pressure passage 64, the left front hydraulic pressure passage 66, the right rear hydraulic pressure passage 118, and the left rear hydraulic pressure passage 120 are respectively provided with a right front wheel pressure reducing valve 42FR, a left front wheel pressure reducing valve 42FL, and a right rear wheel pressure value. The pressure reducing valve 42RR and the left rear wheel pressure reducing valve 42RL communicate with each other.

  Each pressure reducing valve 42 communicates with a hydraulic supply / discharge pipe 28 communicating with the reservoir tank 26. The right front wheel pressure reducing valve 42FR and the left front wheel pressure reducing valve 42FL are maintained in a closed state when a drive signal is not supplied from the ECU 90. On the other hand, the right rear wheel pressure reducing valve 42RR and the left rear wheel pressure reducing valve 42RL are maintained in the open state when the drive signal is not supplied from the ECU 90. Each pressure reducing valve 42 is supplied from the right front hydraulic pressure passage 64, the left front hydraulic pressure passage 66, the right rear hydraulic pressure passage 118, and the left rear hydraulic pressure passage 120 when a drive signal is supplied from the ECU 90, that is, The brake fluid is caused to flow out from the wheel cylinders 20FR, 20FL, 20RR, 20RL to the hydraulic supply / discharge pipe 28 side so that the wheel cylinder pressure corresponding to the drive signal is generated.

  Next, the operation of the brake control device of the present embodiment will be described. In the system of the present embodiment, when all the control valves included in the system are maintained in the OFF state, that is, in the state shown in FIG. 1, the wheel cylinders 20FR, 20FL, 20RR, 20RL of each wheel are disconnected from the accumulator 50, In addition, the mechanical pressure increasing valve 56, the check valve 60, and the master cylinder 14 can be electrically connected. In this case, the hydraulic pressure Pc increased by the mechanical pressure increasing valves 56 and 58 is guided to the wheel cylinders 20FR and 20FL of the left and right front wheels.

As described above, the mechanical pressure increase valves 56 and 58 generate the hydraulic pressure Pc by a mechanical mechanism using the master cylinder pressure P _{M / C} generated by the master cylinder 14 as a pilot pressure. Therefore, under the above situation, the wheel cylinder pressure P _{M / C} of all the wheel cylinders 20FR, 20FL, 20RR, 20RL is controlled using the master cylinder 14 as a hydraulic pressure source without any electrical control. be able to. Hereinafter, as described above, a method of controlling the wheel cylinder pressure P _{M / C} using the master cylinder 14 as a hydraulic pressure source (that is, without interposing electrical control) is referred to as master pressurization.

In the system of the present embodiment, when all the on-off valves included in the system are turned on, that is, when the right master cut valve 22FR, the left master cut valve 22FL, and the accumulator cut valve 116 are closed, all the wheel cylinders 20FR, 20FL, 20RR, and 20RL can be shut off from the mechanical pressure increase valve 56, the check valve 60, and the master cylinder 14, and the accumulator pressure P _ACC can be led to the upstream side of all the pressure increase valves 40.

Under the above circumstances, when the pressure increasing valve 40 and the pressure reducing valve 42 are controlled so that the output signals pFR, pFL, pRR, pRL corresponding to each wheel coincide with the target wheel cylinder pressure P _{W / C} , the wheel of each wheel is controlled. the cylinder pressure P _{M / C,} the accumulator 50 can be controlled to the target wheel cylinder pressure P _{M / C} as a hydraulic pressure source. As described above, according to the system of the present embodiment, the master cylinder 14 is used as a hydraulic pressure source by turning on all the open / close valves and appropriately controlling the pressure increasing valve 40 and the pressure reducing valve 42. In addition, the wheel cylinder pressure P _{M / C} of each wheel can be appropriately controlled using only electrical control using the accumulator 50 as a hydraulic pressure source. Hereinafter, such a control method is referred to as brake-by-wire pressurization (BBW pressurization).

When the system is functioning normally, the brake control device of the present embodiment adjusts the wheel cylinder pressure P _{M / C} of each wheel by the above-described BBW pressurization. And when the failure which prevents execution of BBW pressurization generate | occur | produces in a system, wheel cylinder pressure PM _{/ C} is adjusted by master pressurization. As described above, the brake control apparatus of the present embodiment, when the accumulator pressure P _ACC is boosted successfully utilizes the accumulator pressure P _ACC even during the execution of the master pressure, left and right front wheels A high hydraulic pressure Pc can be introduced to the wheel cylinders 20FR and 20FL as compared with the master cylinder pressure PM _{/ C.} For this reason, according to the brake control apparatus of the present embodiment, it is possible to effectively use the accumulator pressure P _ACC even when the system fails.

Further, the brake control device of the present embodiment prevents the hydraulic pressure from being released from the mechanical pressure increasing valve 56 side to the high pressure passage 114 side when the accumulator pressure P _ACC is not normally increased. The master cylinder pressure P _{M / C} generated in the master cylinder 14 can also be guided to the left and right front wheel cylinders 20FR, 20FL. For this reason, according to the brake control apparatus of this Embodiment, the fail-safe function excellent with respect to the failure of a system is realizable.

  In the above embodiment, the master cylinder 14 is a “manual hydraulic pressure source”, the accumulator 50 is a “power hydraulic pressure source”, and the stepped piston 78 of the mechanical pressure increasing valve 56 is a “moving member”. The ball valve 96, the valve seat 102, and the needle valve 88 correspond to “communication control mechanism”, respectively. Further, when the ECU 90 detects a failure that prevents the execution of the BBW pressurization, fail safe is realized by executing the master pressurization.

  In the above embodiment, the moving member and the communication control mechanism are realized by using the stepped piston 78, the ball valve 96, the valve seat 102, the needle valve 88, and the like, but the present invention is limited to this. For example, the pressure is displaced by the balance between the hydraulic pressure in the pressurizing chamber 106 and the hydraulic pressure in the high-pressure chamber 110, and one of the high-pressure introduction hole 74 and the air introduction hole 76 is selectively conducted to the pressure-regulating chamber 108. The moving member and the communication control mechanism may be realized using a spool valve.

  In the above-described embodiment, the mechanical pressure increasing valve 56 has the drain chamber 112 communicated with the reservoir tank 26 from the atmosphere introduction hole 76 through the atmospheric pressure passage 27. The passage 27 may not be connected and may be simply opened to the atmosphere. That is, the drain chamber 112 only needs to be kept at atmospheric pressure.

  Thus, the above-described brake control device 10 can exhibit a sufficient braking ability and a good brake feeling. However, as a result of intensive studies by the present inventors, it has been found that oil hammer occurs under certain conditions. The mechanism will be briefly described below.

FIG. 3 is a diagram showing the relationship between the master cylinder pressure and the wheel cylinder pressure during master pressurization. When the brake pedal 12 is operated, a master cylinder pressure P _{M / C} corresponding to the brake depression force is generated. Accordingly, the wheel cylinder pressure _{W / C} also increases due to the brake fluid passing through the check valve 60. At that time, in the mechanical pressure increasing valve 56, the brake fluid reaches the pressure regulating chamber 108 from the master pressure introducing hole 70 through the pressurizing chamber 106, and the stepped piston 78 moves toward the pressure regulating chamber 108 side by the urging force. To displace. During this time, the wheel cylinder pressure _{W / C} rises in proportion to the master cylinder pressure P _{M / C.}

Thereafter, when the amount of displacement of the stepped piston 78 toward the pressure regulating chamber 108 reaches a predetermined amount, the needle valve 88 closes the through hole 86, so that the flow of brake fluid into the pressure regulating chamber 108 is blocked. The master cylinder pressure PM _{/ C at} this time is Pmc1 shown in FIG. Until the stepped piston 78 is further displaced and the ball valve 96 is opened, the accumulator 50 and the pressure regulating chamber do not communicate with each other, and therefore the pressure increasing function by the mechanical pressure increasing valve 56 is not exhibited.

However, the brake control device 10 according to the present embodiment includes a check valve 60 in parallel with the mechanical pressure increase valve 56. Therefore, it is possible to flow into the right front wheel cylinder 20FR brake fluid through the check valve 60, the wheel cylinder pressure _{W / C} with the increase in the master cylinder pressure P _{M / C} is further increased.

When the stepped piston 78 is further displaced and the ball valve 96 is separated from the valve seat 102, the high pressure chamber 110 and the pressure regulating chamber 108 are brought into conduction. The master cylinder pressure PM _{/ C at} this time is Pmc2 shown in FIG. When the ball valve 96 is opened, thereafter, the internal pressure of the pressure regulating chamber 108 becomes higher than the master cylinder pressure P _{M / C.} Therefore, the check valve 60 is closed, and a pressure increasing operation and a pressure reducing operation (see hysteresis H shown in FIG. 3) are performed by the mechanical pressure increasing valve 56.

As described above, in the pressure increasing operation shown in FIG. 3, when the master cylinder pressure P _{M / C} = Pmc2, the mechanical pressure increasing valve 56 is changed from the pressure increasing operation (static pressure operation) mainly using the master cylinder 14 to the main pressure increasing valve 56. It switches to the pressure increasing operation. At this time, since the pressure on the wheel cylinder 20FR side of the check valve 60 becomes larger than that on the master cylinder 14 side, the check valve 60 is closed. However, at the initial stage when the check valve 60 starts to close, there is almost no differential pressure on both sides of the check valve 60. For this reason, the valve closing operation of the check valve 60 becomes unstable, and this may cause vibration of the check valve 60 itself and fluctuation of the hydraulic pressure in the vicinity of the check valve 60. Such a phenomenon also contributes to the transmission of the oil hammer to the manual hydraulic pressure source side, and also causes the driver to feel uncomfortable with the brake operation.

  Therefore, the brake control device 10 according to the present embodiment is more directly controlled to enable the check valve 60 to be stably closed in order to suppress an uncomfortable feeling with respect to the brake operation at the time of master pressurization. It has been adopted.

  FIG. 4 is a diagram showing the relationship between the master cylinder pressure and the wheel cylinder pressure when the master pressure is applied in the hydraulic control apparatus according to the present embodiment. FIG. 5 is a diagram showing a flowchart of the initial check according to the present embodiment.

  The following control operation is executed when it is determined immediately after the ignition switch of the vehicle is turned on whether or not the mechanical pressure increasing valve functions normally with the master pressurization. The execution of such a control operation is not limited to the timing described above, and can be appropriately performed as long as it does not affect the braking of the vehicle. In the following description, the right front wheel system will be described, and the left front wheel system will be omitted because it is the same as the right front wheel system.

  The ECU 90 activates the system when the ignition switch is turned on, and starts control according to the present embodiment. First, it is determined whether or not the brake pedal 12 is depressed based on the detection result of the stroke sensor 46 and the like (S10). When depression of the brake pedal 12 is not detected (No in S10), it is determined whether a predetermined time has elapsed since the start of the current control (S11). If it is determined that the predetermined time has elapsed (Yes in S11), the process ends. When it is determined that the predetermined time has not elapsed (No in S11), the process returns to Step S10 again.

When depression of the brake pedal 12 is detected (Yes in S10), the right master cut valve 22FR is closed (S12), and the hydraulic pressure is transmitted between the mechanical pressure increasing valve 56 and the right front wheel wheel cylinder 20FR. Is cut off. In this state, if the depression of the brake pedal 12 is continued, the master cylinder pressure PM _{/ C} is increased by the master cylinder 14, but the right master cut valve 22FR is closed, so that the wheel cylinder pressure _{W / C} is It does not change.

Thereafter, when the master cylinder pressure P _{M / C} increases to Pmc2, the check valve 60 is closed. At that time, since the right master cut valve 22FR is closed, the downstream path of the mechanical pressure increasing valve 56 is substantially regarded as a rigid body, and the mechanical pressure increased by using the hydraulic pressure of the accumulator 50. The hydraulic pressure on the downstream side of the pressure increasing valve 56 rises more smoothly, and the check valve 60 that has been opened until then is stably closed. Therefore, the pressure on the downstream side of the check valve 60 rises smoothly, and when the pressure becomes greater than the master cylinder pressure P _{M / C} , the check valve 60 is stably closed. In the present embodiment, the right master cut valve 22FR is opened after the differential pressure on both sides of the check valve 60 has increased to some extent so that the state where the check valve 60 is once closed is stably maintained. The control is performed.

Specifically, the ECU 90 determines whether or not the master cylinder pressure PM _{/ C} is greater than Pmc0 based on the detection result of the right master pressure sensor 48FR (S14). Here, Pmc0 is set as a larger value than Pmc2 (see FIG. 4). Pmc0 may be set as a value theoretically calculated in consideration of the configuration of the entire system, or may be set as a value actually obtained experimentally.

When the master cylinder pressure P _{M / C} is equal to or lower than Pmc0 (No in S14), the process returns to step S10 again. When the master cylinder pressure P _{M / C} is larger than Pmc0 (Yes in S14), the ECU 90 opens the right master cut valve 22FR on the assumption that a sufficient differential pressure has occurred on both sides of the check valve 60 (S16). As a result, the check valve 60 cannot be closed in an unstable manner, and vibration is not generated and the oil hammer is not transmitted to the master cylinder 14 side.

Thereafter, the master cylinder pressure PM _{/ C} and the wheel cylinder pressure _{W / C} are detected based on each sensor (S18), and based on the detection result, the ECU 90 determines whether there is an abnormality in the operation of the brake control device 10 ( S20). When an abnormality is detected (Yes in S20), a warning operation such as lighting of a warning lamp or a warning sound is performed (S22), and the process ends. If no abnormality is detected (No in S20), other normal operations such as initial check and operation check are performed (S24), and the process ends.

  In summary, the ECU 90 does not open the right master cut valve 22FR that is closed immediately after the check valve 60 is closed, but the hydraulic pressure generated in the master cylinder 14 is somewhat. After rising, the right master cut valve 22FR is opened. That is, the right master cut valve 22FR is opened when the hydraulic pressure in the master cylinder 14 reaches the target hydraulic pressure Pmc0 that is set higher than the hydraulic pressure Pmc2 in the master cylinder 14 when the check valve 60 is closed. The Thus, when the right master cut valve 22FR is opened, a certain amount of differential pressure ΔP (see FIG. 4) is generated on the upstream side and the downstream side of the check valve 60. Therefore, it is also possible to prevent the check valve 60 from becoming unstable due to pressure fluctuation caused by the brake fluid that has been increased by the mechanical pressure increasing valve 56 flowing out toward the wheel cylinder 20FR.

  FIG. 6 is a system diagram showing an outline of a hydraulic control apparatus according to another embodiment. The hydraulic control device 210 is different from the brake control device 10 in that an orifice 202 is provided between the accumulator 50 and the accumulator cut valve 116. As a result, rapid fluid pressure transmission from the accumulator 50 to the mechanical pressure increasing valves 56, 58 is suppressed, and as a result, rapid fluctuations in fluid pressure generated on the wheel cylinder side of the mechanical pressure increasing valves 56, 58 are suppressed. The

  The size and shape of the orifice are appropriately designed according to required specifications and costs such as responsiveness and braking force while suppressing the occurrence of oil hammer. FIG. 7 is a diagram schematically showing required characteristics required for the orifice.

  A straight line L1 shown in FIG. 7 indicates the maximum gradient that can prevent the occurrence of oil hammer due to a rapid increase in pressure. A broken line L2 indicates a response request line in which the pressure increase gradient changes between a low pressure and a high pressure as a response request during braking. As shown in FIG. 7, as a characteristic of the orifice, a curve C indicating a temporal change in hydraulic pressure when the brake pedal is depressed may be present in a region between the straight line L1 and the broken line L2.

  In general, when the pressure rises, the pressure difference between the hydraulic pressure of the wheel cylinder and each hydraulic pressure source becomes small, so that the time change of the pressure tends to become small. Therefore, by reducing the inclination of the response request line on the high pressure side as indicated by the broken line L2, even if the change in hydraulic pressure over time is as shown by the curve C, the request from the viewpoint of oil hammer and responsiveness can be satisfied. . As a result, the orifice diameter can be reduced, and oil hammering can be easily prevented.

  As described above, the present invention has been described with reference to the above-described embodiment. However, the present invention is not limited to the above-described embodiment, and the present invention can be appropriately combined or replaced with the configuration of the embodiment. It is included in the present invention. Various modifications such as design changes can be added to the embodiments based on the knowledge of those skilled in the art, and the embodiments to which such modifications are added can be included in the scope of the present invention. .

  DESCRIPTION OF SYMBOLS 10 Brake control apparatus, 12 Brake pedal, 14 Master cylinder, 16 Brake hydraulic control pipe, 16a 1st flow path, 16b 2nd flow path, 18 Brake hydraulic control pipe, 20 Wheel cylinder, 22FL Left master cut valve, 22FR Right master Cut valve, 26 reservoir tank, 27 atmospheric pressure passage, 28 hydraulic supply / discharge pipe, 29 pump hydraulic passage, 34 pump, 40 pressure increasing valve, 42 pressure reducing valve, 44 wheel cylinder pressure sensor, 48FL left master pressure sensor, 48FR right master Pressure sensor, 50 accumulator, 51 accumulator pressure sensor, 56 mechanical pressure increase valve, 60 check valve, 68 housing, 80 hydraulic actuator, 90 ECU, 114 high pressure passage, 116 accumulator cut valve, 1 8 Right rear fluid pressure passage, 120 rear left fluid pressure passage, 200 fluid pressure control device, 202 orifices.

Claims (3)

A manual hydraulic pressure source that pressurizes the stored hydraulic fluid according to the amount of operation of the brake operation member by the driver;
A power hydraulic pressure source capable of accumulating with hydraulic fluid using power independent of the driver's brake operation;
A wheel cylinder that receives a supply of hydraulic fluid from at least one of the manual hydraulic pressure source and the power hydraulic pressure source and applies a braking force to the wheel;
A manual hydraulic pressure transmission path configured to connect the manual hydraulic pressure source and the wheel cylinder, and to supply hydraulic fluid from the manual hydraulic pressure source to the wheel cylinder;
A power hydraulic pressure transmission path configured to connect the power hydraulic pressure source and the wheel cylinder, and to supply hydraulic fluid from the power hydraulic pressure source to the wheel cylinder;
A power hydraulic pressure source is provided at the time of pressure increase in order to cause the wheel cylinder to generate a hydraulic pressure having a predetermined pressure increasing ratio with respect to the hydraulic pressure generated by the manual hydraulic pressure source, provided in the first flow path of the manual hydraulic pressure transmission path. Pressure increase mechanism that can introduce hydraulic fluid from the wheel cylinder side,
When the manual hydraulic pressure source side is higher than the wheel cylinder side, the pressure on the manual hydraulic pressure source side is connected to the second flow path provided in parallel with the first flow path so as to bypass the pressure increasing mechanism. A check valve with substantially zero valve opening pressure that transmits to the cylinder side and suppresses backflow of the hydraulic fluid on the wheel cylinder side to the manual hydraulic pressure source side;
A control valve that is provided on the downstream side of the pressure increasing mechanism and the check valve, and that controls the supply of hydraulic fluid from the pressure increasing mechanism or the check valve to the wheel cylinder;
A control unit for controlling opening and closing of the control valve,
The controller is
When the operation of the brake operating member is detected under a predetermined condition, the control valve is closed,
Thereafter, when the hydraulic pressure generated by the manual hydraulic pressure source reaches a target hydraulic pressure that is set higher than the hydraulic pressure when the check valve that has been opened is closed, the control valve is turned on. To open the valve,
A hydraulic control apparatus characterized by the above. The pressure increasing mechanism is
A pressurizing chamber that receives hydraulic pressure from the master cylinder;
A moving member biased in one direction by the hydraulic pressure of the pressurizing chamber;
A pressure regulating chamber for storing hydraulic pressure for urging the moving member in the other direction;
When the moving member is displaced in the one direction over a predetermined distance, the power hydraulic pressure source and the pressure regulating chamber are in communication with each other, and the moving member is displaced in the other direction over a predetermined distance. A communication control mechanism that shuts off the power hydraulic pressure source and the pressure regulating chamber in a case,
2. The liquid according to claim 1, wherein the moving member is configured such that a ratio of an area of the end surface on the pressurizing chamber side to an area of the end surface on the pressure adjusting chamber side is the same as the pressure increasing ratio. Pressure control device.   The hydraulic control apparatus according to claim 1, wherein an orifice is provided between the power hydraulic pressure source and the pressure increasing mechanism.

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