JP7052533B2 - Vehicle braking device - Google Patents

Description

The present invention relates to a vehicle braking device.

Some vehicle braking devices use a regulator as part of the boosting mechanism. The regulator includes a cylinder body and a spool, and is a mechanism in which the spool is slid in the cylinder body by pilot pressure and the output pressure is adjusted according to the position of the spool. In detail, the cylinder body is located between the pressure chamber where the output pressure of the master cylinder to the servo chamber is generated, the high pressure port located between the high pressure source and the pressure chamber, and the low pressure source and the pressure chamber. A low pressure port is provided.

The spool is within a predetermined range within the cylinder body, including a closed range in which the spool closes both the high pressure port and the low pressure port, and an open range in which the spool closes one of the high pressure port and the low pressure port and opens the other. It is configured to be slidable. The hydraulic pressure (output pressure) in the pressure chamber is maintained when both the high pressure port and the low pressure port are closed, and when only the high pressure port is opened, the pressure is increased toward the pressure of the high pressure source, and only the decompression port is opened. Then, the pressure is reduced toward the pressure of the low pressure source (for example, atmospheric pressure). That is, regarding the output pressure, when the spool is located in the closed range, it is in the holding state, and when the spool is located in the open range, it is in the increasing pressure state or the depressurizing state.

In this configuration, when the spool passes through the closed range and heads for the open range in response to a pressure increase instruction or a depressurization instruction, the output pressure increases or decreases at a level corresponding to the operation amount while the spool slides in the closed range. Instead, this sliding section becomes an invalid section (invalid liquid amount) in which the master pressure (output pressure of the master cylinder) does not react to the pressure increase instruction or the depressurization instruction. On the other hand, for example, in the hydraulic pressure generator described in Japanese Patent Application Laid-Open No. 2017-30421, shortening control is performed in which the change gradient of the pilot pressure is made larger than usual when the spool passes through the closed range and goes to the open range. It is done. As a result, the sliding time of the invalid section of the spool is shortened, and the responsiveness to the brake operation is improved.

Japanese Unexamined Patent Publication No. 2017-30421

The end determination of this shortening control is performed, for example, based on the amount of change in the servo pressure. However, in this configuration, it is difficult to distinguish whether the increase in servo pressure is due to the spool reaching the open range (first factor) or the spool sliding in the closed range (second factor). Met. That is, in the conventional control, there has been a case where the shortening control is completed earlier than the target.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vehicle braking device capable of accurately terminating shortening control that shortens the sliding time of the spool closing range. do.

The vehicle braking device of the present invention includes a master cylinder body, a master piston sliding in the master cylinder body, a master cylinder having a servo chamber in which a servo pressure for sliding the master piston is generated, a high pressure port, and a low pressure. Sliding including a cylinder body in which a port is formed, a closed range in which both the high pressure port and the low pressure port are closed, and an open range in which one of the high pressure port and the low pressure port is closed and the other is open. A spool that can slide in the cylinder body within a range, a pilot chamber that generates a pilot pressure for sliding the spool, and a pressure chamber that is connected to the servo chamber and whose volume changes due to the sliding of the spool. A hydraulic pressure generating portion, a high-pressure source that supplies a hydraulic fluid having a predetermined pressure or more to the pressure chamber via the high-pressure port when the spool opens the high-pressure port and is located in the open range, and the spool. A low pressure source maintained at a pressure lower than the predetermined pressure, which is connected to the pressure chamber via the low pressure port when the low pressure port is opened and is located in the open range, and a target value of the servo pressure. The amount of change in the pilot pressure per unit time for sliding the spool in the closed range is larger than the amount of change in the pilot pressure per unit time due to the normal control. A pilot pressure control unit that executes shortening control to increase at different timings, a pressure detection unit that detects the pressure of the high pressure source, and a change gradient on the pressure reduction side of the high pressure source detected by the pressure detection unit. A control switching unit for terminating the shortening control when the pressure exceeds a predetermined gradient is provided.

When the high-pressure source supplies the brake fluid to the servo chamber through the pressure chamber, the pressure change gradient of the high-pressure source becomes large. According to the present invention, by detecting this change gradient, the cause of the increase in the servo pressure can be identified, and the shortening control can be terminated with high accuracy.

It is a block diagram of the braking device for a vehicle of this embodiment. It is a time chart which shows an example of the control of this embodiment.

Hereinafter, an embodiment in which the hydraulic pressure control device according to the present invention is applied to a vehicle will be described with reference to the drawings. The vehicle is provided with a vehicle braking device 1 that directly applies a hydraulic braking force to each wheel W to brake the vehicle. As shown in FIG. 1, the vehicle braking device 1 of the present embodiment includes a brake pedal 11, a master cylinder 12, a stroke simulator unit 13, a reservoir 14, a booster mechanism 15, an actuator 16, a brake ECU 17, and a wheel cylinder WC. I have.

The wheel cylinder WC regulates the rotation of the wheel W, and is provided on the caliper. The wheel cylinder WC is a braking force applying mechanism that applies a braking force to the wheels W of the vehicle based on the pressure of the hydraulic fluid from the actuator 16. The brake pedal 11 is a brake operating member. The brake pedal 11 is connected to the stroke simulator unit 13 and the master cylinder 12 via the operation rod 11a.

A stroke sensor 11c for detecting the stroke (operation amount) of the brake pedal 11 is provided in the vicinity of the brake pedal 11. The stroke sensor 11c is connected to the brake ECU 17, and is configured to output the detection result to the brake ECU 17.

The master cylinder 12 supplies brake fluid to the actuator 16 according to the stroke of the brake pedal 11, and is composed of a master cylinder body 12a, an input piston 12b, a first master piston 12c, a second master piston 12d, and the like. ing.

The master cylinder body 12a is formed in a substantially cylindrical shape with a bottom. A partition wall portion 12a2 protruding inwardly into a flange shape is provided on the inner peripheral portion of the master cylinder body 12a. A through hole 12a3 penetrating in the front-rear direction is formed in the center of the partition wall portion 12a2. A first master piston 12c and a second master piston 12d are arranged on the inner peripheral portion of the master cylinder body 12a in a portion in front of the partition wall portion 12a2 so as to be liquid-tight and movable along the axial direction.

An input piston 12b is disposed on the inner peripheral portion of the master cylinder body 12a in a portion behind the partition wall portion 12a2 so as to be liquid-tight and movable along the axial direction. The input piston 12b is a piston that slides in the master cylinder body 12a in response to the operation of the brake pedal 11.

An operation rod 11a linked to the brake pedal 11 is connected to the input piston 12b. The input piston 12b is urged by the compression spring 11b in the direction of expanding the first hydraulic chamber R3, that is, in the rear direction (to the right in the drawing). When the brake pedal 11 is depressed, the operating rod 11a advances against the urging force of the compression spring 11b. As the operation rod 11a advances, the input piston 12b also advances in conjunction with it. When the depressing operation of the brake pedal 11 is released, the input piston 12b retracts due to the urging force of the compression spring 11b and is positioned in contact with the regulation convex portion 12a4.

The first master piston 12c is formed by integrally forming a pressure cylinder portion 12c1, a flange portion 12c2, and a protruding portion 12c3 in order from the front side. The pressure cylinder portion 12c1 is formed in a substantially cylindrical shape with a bottom having an opening at the front, and is liquidtightly and slidably arranged between the pressure cylinder portion 12c1 and the inner peripheral surface of the master cylinder body 12a. In the internal space of the pressure cylinder portion 12c1, a coil spring 12c4 which is an urging member is arranged between the pressure cylinder portion 12c1 and the second master piston 12d. The first master piston 12c is urged rearward by the coil spring 12c4. In other words, the first master piston 12c is urged rearward by the coil spring 12c4 and is finally positioned in contact with the regulation convex portion 12a5. This position is the initial position (original position) of the first master piston 12c, and is the position when the depressing operation of the brake pedal 11 is released.

The flange portion 12c2 is formed to have a larger diameter than the pressure cylinder portion 12c1, and is liquidtightly and slidably arranged on the inner peripheral surface of the large diameter portion 12a6 in the master cylinder body 12a. The protruding portion 12c3 is formed to have a smaller diameter than the pressure cylinder portion 12c1, and is arranged so as to slide in a liquid-tight manner in the through hole 12a3 of the partition wall portion 12a2. The rear end portion of the protruding portion 12c3 passes through the through hole 12a3, protrudes into the internal space of the master cylinder body 12a, and is separated from the inner peripheral surface of the master cylinder body 12a. The rear end surface of the protrusion 12c3 is separated from the bottom surface of the input piston 12b, and the separation distance is configured to be variable.

The second master piston 12d is arranged on the front side of the first master piston 12c in the master cylinder body 12a. The second master piston 12d is formed in a substantially cylindrical shape with a bottom having an opening in the front. In the internal space of the second master piston 12d, a coil spring 12d1 which is an urging member is disposed between the inner bottom surface of the master cylinder body 12a. The second master piston 12d is urged rearward by the coil spring 12d1. In other words, the second master piston 12d is urged by the coil spring 12d1 toward the set initial position.

Further, the master cylinder 12 is formed with a first master chamber R1, a second master chamber R2, a first hydraulic chamber R3, a second hydraulic chamber R4, and a servo chamber R5. The first master chamber R1 is partitioned by an inner peripheral surface of the master cylinder body 12a, a first master piston 12c (front side of the pressure cylinder portion 12c1), and a second master piston 12d. The first master chamber R1 is connected to the reservoir 14 via the oil passage 21 connected to the port PT4. Further, the first master chamber R1 is connected to the actuator 16 via an oil passage 22 connected to the port PT5.

The second master chamber R2 is partitioned by the inner peripheral surface of the master cylinder body 12a and the front side of the second master piston 12d. The second master chamber R2 is connected to the reservoir 14 via the oil passage 23 connected to the port PT6. Further, the second master chamber R2 is connected to the actuator 16 via an oil passage 24 connected to the port PT7.

The first hydraulic chamber R3 is formed between the partition wall portion 12a2 and the input piston 12b, and includes the inner peripheral surface of the master cylinder body 12a, the partition wall portion 12a2, the protruding portion 12c3 of the first master piston 12c, and the input piston. It is partitioned by 12b. The second hydraulic chamber R4 is formed on the side of the pressure cylinder portion 12c1 of the first master piston 12c, and is the inner peripheral surface and the pressure cylinder portion of the large diameter portion 12a6 of the inner peripheral surface of the master cylinder body 12a. It is partitioned by a 12c1 and a flange portion 12c2. The first hydraulic chamber R3 is connected to the second hydraulic chamber R4 via the oil passage 25 connected to the port PT1 and the port PT3.

The servo chamber R5 is formed between the partition wall portion 12a2 and the pressure cylinder portion 12c1 of the first master piston 12c, and is formed on the inner peripheral surface of the master cylinder body 12a, the partition wall portion 12a2, and the protruding portion of the first master piston 12c. It is partitioned by 12c3 and a pressure cylinder portion 12c1. The servo chamber R5 is connected to the output chamber R12 via an oil passage 26 connected to the port PT2.

The pressure sensor 26a is a sensor that detects the servo pressure supplied to the servo chamber R5, and is connected to the oil passage 26. The pressure sensor 26a transmits a detection signal (detection result) to the brake ECU 17. The servo pressure detected by the pressure sensor 26a is an actual value of the hydraulic pressure of the servo chamber R5, and is hereinafter referred to as an actual servo pressure.

The stroke simulator unit 13 includes a master cylinder body 12a, an input piston 12b, a first hydraulic pressure chamber R3, and a stroke simulator 13a that communicates with the first hydraulic pressure chamber R3. The first hydraulic chamber R3 communicates with the stroke simulator 13a via the oil passages 25 and 27 connected to the port PT1. The first hydraulic pressure chamber R3 communicates with the reservoir 14 via a connecting oil passage (not shown).

The stroke simulator 13a generates a reaction force of a magnitude corresponding to the operating state of the brake pedal 11 on the brake pedal 11. The stroke simulator 13a includes a cylinder portion 13a1, a piston portion 13a2, a reaction force hydraulic chamber 13a3, and a spring 13a4. The piston portion 13a2 slides in the cylinder portion 13a1 in a liquid-tight manner as the brake is operated to operate the brake pedal 11. The reaction force hydraulic chamber 13a3 is formed so as to be partitioned between the cylinder portion 13a1 and the piston portion 13a2. The reaction force hydraulic chamber 13a3 communicates with the first hydraulic pressure chamber R3 and the second hydraulic pressure chamber R4 via the connected oil passages 27 and 25. The spring 13a4 urges the piston portion 13a2 in a direction that reduces the volume of the reaction force hydraulic chamber 13a3.

The oil passage 25 is provided with a first control valve 25a, which is a normally closed type solenoid valve. A second control valve 28a, which is a normally open type solenoid valve, is provided in the oil passage 28 connecting the oil passage 25 and the reservoir 14. When the first control valve 25a is in the closed state, the first hydraulic chamber R3 and the second hydraulic chamber R4 are shut off. As a result, the input piston 12b and the first master piston 12c are interlocked with each other while maintaining a constant separation distance. Further, when the first control valve 25a is in the open state, the first hydraulic pressure chamber R3 and the second hydraulic pressure chamber R4 are communicated with each other. As a result, the volume change of the first hydraulic chamber R3 and the second hydraulic chamber R4 accompanying the advance / retreat of the first master piston 12c is absorbed by the movement of the brake fluid.

The pressure sensor 25b is a sensor that detects the hydraulic pressure (reaction hydraulic pressure) of the second hydraulic chamber R4 and the first hydraulic chamber R3, and is connected to the oil passage 25. The pressure sensor 25b is also an operating force sensor that detects an operating force with respect to the brake pedal 11, and has an interrelationship with the stroke of the brake pedal 11. The pressure sensor 25b detects the pressure in the second hydraulic chamber R4 when the first control valve 25a is in the closed state, and communicates with the first hydraulic chamber R3 when the first control valve 25a is in the open state. Pressure will also be detected. The pressure sensor 25b transmits a detection signal (detection result) to the brake ECU 17.

The booster mechanism 15 generates a servo pressure according to the stroke of the brake pedal 11. The booster mechanism 15 is a hydraulic pressure generator that outputs an output pressure (servo pressure in this embodiment) by acting on an input input pressure (pilot pressure in this embodiment). The booster mechanism 15 includes a regulator (corresponding to a “hydraulic pressure generating portion”) 15a and a pressure supply device 15b.

The regulator 15a includes a cylinder body 15a1 and a spool 15a2 that slides in the cylinder body 15a1. A pilot chamber R11, an output chamber R12, and a third hydraulic pressure chamber R13 are formed in the regulator 15a.

The pilot chamber R11 is partitioned by a cylinder body 15a1 and a front end surface of a second large diameter portion 15a2b of the spool 15a2. The pilot chamber R11 is connected (to the oil passage 31) to the pressure reducing valve 15b6 and the pressure increasing valve 15b7 connected to the port PT11. Further, the inner peripheral surface of the cylinder body 15a1 is provided with a regulated convex portion 15a4 which is positioned by abutting the front end surface of the second large diameter portion 15a2b of the spool 15a2.

The output chamber R12 is partitioned by the cylinder body 15a1, the small diameter portion 15a2c of the spool 15a2, the rear end surface of the second large diameter portion 15a2b, and the front end surface of the first large diameter portion 15a2a. The output chamber R12 is connected to the servo chamber R5 via the port PT12, the oil passage 26, and the port PT2. Further, the output chamber R12 can be connected to the accumulator 15b2 via the high pressure port PT13 and the oil passage 32.

The third hydraulic chamber R13 is partitioned by the cylinder body 15a1 and the rear end surface of the first large diameter portion 15a2a of the spool 15a2. The third hydraulic chamber R13 can be connected to the reservoir 15b1 via the low pressure port PT14 and the oil passage 33. Further, in the third hydraulic pressure chamber R13, a spring 15a3 for urging the spool 15a2 in the direction of expanding the third hydraulic pressure chamber R13 is disposed.

The spool 15a2 includes a first large diameter portion 15a2a, a second large diameter portion 15a2b, and a small diameter portion 15a2c. The first large-diameter portion 15a2a and the second large-diameter portion 15a2b are configured to slide in the cylinder body 15a1 in a liquid-tight manner. The small diameter portion 15a2c is arranged between the first large diameter portion 15a2a and the second large diameter portion 15a2b, and is integrally formed with the first large diameter portion 15a2a and the second large diameter portion 15a2b. .. The small diameter portion 15a2c is formed to have a smaller diameter than the first large diameter portion 15a2a and the second large diameter portion 15a2b.

Further, the spool 15a2 is formed with a communication passage 15a5 for communicating the output chamber R12 and the third hydraulic pressure chamber R13. The pressure chamber R14 is composed of the output chamber R12 and the third hydraulic pressure chamber R13. The pressure chamber R14 is configured so that the volume decreases as the spool 15a2 retracts and increases as the spool 15a2 advances. As described above, the pressure chamber R14 is a portion connected to the servo chamber R5 and whose volume changes due to the sliding of the spool 15a2.

The pressure supply device 15b is also a drive unit for driving the spool 15a2. The pressure supply device 15b sucks the reservoir (corresponding to the "low pressure source") 15b1, the accumulator (corresponding to the "high pressure source") 15b2 for accumulating the brake fluid, and the brake fluid of the reservoir 15b1 and discharges the brake fluid to the accumulator 15b2. It includes a pump 15b3 and an electric motor 15b4 for driving the pump 15b3. The reservoir 15b1 is open to the atmosphere, and the hydraulic pressure of the reservoir 15b1 is the same as the atmospheric pressure. The pressure in the reservoir 15b1 (here atmospheric pressure) is lower than the pressure in the accumulator 15b2.

The pressure supply device 15b includes a pressure sensor (corresponding to a "pressure detection unit") 15b5 that detects the pressure of the brake fluid supplied from the accumulator 15b2 and outputs the detection result to the brake ECU 17. That is, the pressure supply device 15b includes a pressure sensor 15b5 that detects the pressure of the accumulator 15b2. When the detection result of the pressure sensor 15b5 is smaller than the predetermined lower limit value (corresponding to the "predetermined pressure"), the brake ECU 17 drives the electric motor 15b4 and the pump 15b3 to maintain the pressure of the accumulator 15b2 at or above the predetermined lower limit value. .. The accumulator 15b2 is configured so that when the detection result of the pressure sensor 15b5 becomes less than a predetermined lower limit value, the brake fluid is supplied from the pump 15b3 driven by the electric motor 15b4. The pressure of the accumulator 15b2 is maintained, for example, within a predetermined pressure range (between a predetermined lower limit value and a predetermined upper limit value). The reservoir 15b1 is maintained at a pressure lower than a predetermined pressure.

Further, the pressure supply device 15b includes a pressure reducing valve 15b6 and a pressure increasing valve 15b7. Specifically, the pressure reducing valve 15b6 is a solenoid valve having a structure (normally open type) that opens in a non-energized state, and the flow rate is controlled by a command from the brake ECU 17. One of the pressure reducing valves 15b6 is connected to the pilot chamber R11 via the oil passage 31, and the other of the pressure reducing valves 15b6 is connected to the reservoir 15b1 via the oil passage 34. The booster valve 15b7 is a solenoid valve having a structure (normally closed type) that closes in a non-energized state, and the flow rate is controlled by a command from the brake ECU 17. One of the booster valves 15b7 is connected to the pilot chamber R11 via the oil passage 31, and the other of the booster valves 15b7 is connected to the accumulator 15b2 via the oil passage 35 and the oil passage 32 to which the oil passage 35 is connected. There is.

Here, the operation of the regulator 15a will be briefly described. When the pilot pressure (hydraulic pressure of the pilot chamber R11) is not supplied from the pressure reducing valve 15b6 and the pressure increasing valve 15b7 to the pilot chamber R11, the spool 15a2 is urged by the spring 15a3 and is in the initial position (see FIG. 1). The initial position of the spool 15a2 is a position where the front end surface of the spool 15a2 abuts on the regulation convex portion 15a4 and is positioned and fixed, and the rear end surface of the spool 15a2 is a position adjacent to the front end surface of the low pressure port PT14.

As described above, when the spool 15a2 is in the initial position, the low pressure port PT14 and the port PT12 communicate with each other via the pressure chamber R14, and the high pressure port PT13 is blocked by the spool 15a2.

The pilot pressure is formed by the pressure reducing valve 15b6 and the pressure increasing valve 15b7 according to the stroke of the brake pedal 11. When the pilot pressure is increased, the spool 15a2 moves backward (to the right in FIG. 1) against the urging force of the spring 15a3. Then, the spool 15a2 moves to a position where the high pressure port PT13 blocked by the spool 15a2 is opened. Further, the low pressure port PT14 that has been opened is blocked by the spool 15a2. The position of the spool 15a2 in this state is referred to as a “pressure increasing position”. At this time, the pressure chamber R14 and the accumulator 15b2 communicate with each other via the high pressure port PT13 (pressure increasing state). Further, the rear end surface of the second large diameter portion 15a2b of the spool 15a2 receives a force corresponding to the servo pressure.

Then, the spool 15a2 is positioned by balancing the pressing force of the front end surface of the second large diameter portion 15a2b of the spool 15a2 with the resultant force of the force corresponding to the servo pressure and the urging force of the spring 15a3. The position of the spool 15a2 in which the high pressure port PT13 and the low pressure port PT14 are blocked by the spool 15a2 is defined as a “holding position”. At this time, the connection between the pressure chamber R14 and the accumulator 15b2 and the reservoir 15b1 is cut off (holding state).

Further, when the pilot pressure is reduced, the spool 15a2 in the holding position moves forward by the urging force of the spring 15a3. Then, the high-pressure port PT13 blocked by the spool 15a2 is maintained in the closed state, and the closed low-pressure port PT14 is opened. The position of the spool 15a2 in this state is referred to as a "decompression position". At this time, the pressure chamber R14 and the reservoir 15b1 communicate with each other via the low pressure port PT14 (reduced pressure state). At the initial position of the spool 15a2 (pilot pressure = pressure of the reservoir 15b1), the high pressure port PT13 is closed and the low pressure port PT14 is open, and the initial position corresponds to the decompression position.

Here, in the sliding range of the spool 15a2, the range in which both the high pressure port PT13 and the low pressure port PT14 are closed is referred to as a “closed range”, and one of the high pressure port PT13 and the low pressure port PT14 is closed and the other is open. The range to be set is referred to as an "open range". The position of the spool 15a2 in the closed range has the same meaning as the position of the spool 15a2 in the holding position. Further, the position of the spool 15a2 in the open range has the same meaning as the position of the spool 15a2 in the pressure increasing position or the depressurizing position. As described above, the spool 15a2 is configured to be slidable in the cylinder body 15a1 within a sliding range including the closed range and the open range.

The booster mechanism 15 generates a pilot pressure in the pilot chamber R11 according to the stroke of the brake pedal 11 by the pressure reducing valve 15b6 and the pressure increasing valve 15b7. Then, the servo pressure corresponding to the stroke of the brake pedal 11 is generated in the servo chamber R5 by the pilot pressure. The master cylinder 12 supplies the master pressure (hydraulic pressure of the first master chamber R1 and the second master chamber R2) generated according to the stroke of the brake pedal 11 to the wheel cylinder WC via the actuator 16. The pressure reducing valve 15b6 and the pressure increasing valve 15b7 constitute a valve mechanism for adjusting the inflow and outflow of the brake fluid to and from the servo chamber R5.

The actuator 16 is a device that is arranged between the master cylinder 12 and the wheel cylinder WC and adjusts the hydraulic pressure applied to each wheel cylinder WC. The actuator 16 is composed of a solenoid valve (not shown), a motor, a pump, and the like (not shown). The actuator 16 executes anti-skid control (ABS control) or the like based on a command from the brake ECU 17.

The brake ECU 17 is an electronic control unit including a CPU and a memory. The brake ECU 17 receives the detection results of various sensors and controls various devices (solenoid valves, etc.) based on the detection results. Further, a detection signal from the wheel speed sensor S provided for each wheel W of the vehicle is input to the brake ECU 17.

The brake ECU 17 includes a control unit 171 and a control switching unit 172 as functions. The control unit 171 determines the normal control for controlling the pilot pressure according to the target value of the servo pressure (hereinafter referred to as the target servo pressure) and the control based on the target servo pressure and the time for the spool 15a2 to slide in the closed range. It is configured to execute shortening control that is shorter than the sliding time by normal control at different timings. The control unit 171 sets the target servo pressure based on the stroke of the brake pedal 11 (detected value of the stroke sensor 11c).

In normal control, the control unit 171 controls the pressure reducing valve 15b6 and the pressure increasing valve 15b7 so that the actual servo pressure approaches the target servo pressure, and executes pressure increasing control, holding control, or depressurizing control for the servo chamber R5. do. The shortening control is a control in which the amount of change in the pilot pressure per unit time for sliding the spool 15a2 in the closed range is larger than the amount of change in the pilot pressure per unit time due to the normal control. That is, the shortening control is a control in which when the spool 15a2 moves to the open range through the closed range, the speed at which the spool 15a2 slides in the closed range is higher than that in the normal control. When executing the shortening control, the control unit 171 makes the inflow / outflow amount of the hydraulic fluid to the pilot chamber R11 per unit time larger than the inflow / outflow amount by the normal control. For example, when the pressure increase control is executed when the spool 15a2 is located at the holding position, the control unit 171 executes shortening control until the spool 15a2 reaches the pressure increasing position from the holding position, and moves to the pressure increasing position. After reaching it, normal control is executed. As a result, it is possible to shorten the sliding time in the closed range in which the control amount to the pilot pressure is not reflected in the actual servo pressure in the sliding range of the spool 15a2, and the responsiveness is improved.

It can be said that the control unit 171, the pressure reducing valve 15b6, and the pressure increasing valve 15b7 constitute the pilot pressure control unit 8 that selectively executes normal control and shortening control. That is, the pilot pressure control unit 8 is a pressure increasing valve 15b7 provided in the flow path 35 connecting the accumulator 15b2 and the pilot chamber R11, and a pressure reducing valve provided in the flow path 34 connecting the reservoir 15b1 and the pilot chamber R11. It has a pressure increasing valve 15b7 and a control unit 171 that controls a pressure increasing valve 15b7 and a pressure reducing valve 15b6. The supply destinations of the brake fluid of the accumulator 15b2 are the pilot chamber R11, the servo chamber R5, and the pressure chamber R14.

The control switching unit 172 is configured to terminate shortening control based on the detection result of the pressure sensor 15b5. The control switching unit 172 ends the shortening control based on the change gradient (inclination) of the pressure of the accumulator 15b2 (hereinafter referred to as “accumulator pressure”) detected by the pressure sensor 15b5. When the accumulator pressure decrease gradient (change gradient to the decrease side) exceeds a predetermined gradient, the control switching unit 172 switches the control of the control unit 171 from shortening control to normal control. The control switching unit 172 calculates the change gradient of the accumulator pressure at predetermined time intervals. The predetermined gradient is a preset gradient threshold.
As described above, in the vehicle braking device 1 of the present embodiment, the master cylinder body 12a, the master pistons 12c and 12d sliding in the master cylinder body 12a, and the servo pressure for sliding the master pistons 12c and 12d are generated. A master cylinder 12 having a servo chamber R5, a cylinder body 15a1 in which a high pressure port PT13 and a low pressure port PT14 are formed, and a spool 15a2 slidable in the cylinder body 15a1 within a sliding range including a closed range and an open range. A regulator 15a having a pilot chamber R11 in which a pilot pressure for sliding the spool 15a2 is generated, a pressure chamber R14 connected to the servo chamber R5 and whose volume changes due to the sliding of the spool 15a2, and a spool 15a2 having a high pressure port PT13. When the accumulator 15b2 for supplying a working fluid having a predetermined pressure or more to the pressure chamber R14 via the high pressure port PT13 and the spool 15a2 open the low pressure port PT14 and are located in the open range. The reservoir 15b1 connected to the pressure chamber R14 via the low pressure port PT14 and maintained at a pressure lower than the predetermined pressure, the normal control for controlling the pilot pressure according to the target value of the servo pressure, and the spool 15a2 in the closed range. The pilot pressure control unit 8 and the accumulator 15b2 execute shortening control in which the change amount of the pilot pressure sliding in the above per unit time is larger than the change amount of the pilot pressure per unit time by normal control at different timings. A pressure sensor 15b5 for detecting the pressure and a control switching unit 172 for terminating the shortening control based on the pressure change gradient of the accumulator 15b2 detected by the pressure sensor 15b5 are provided.

As shown in FIG. 2, at time t1, shortening control is started based on the pressure boosting instruction (shortening control ON), and when the pressure boosting valve 15b7 is opened (valve opening flag ON), the accumulator 15b2 is transferred to the pilot chamber R11. High pressure brake fluid is supplied. As a result, the spool 15a2 slides and the volume of the closed pressure chamber R14 decreases in the closed range, so that the hydraulic pressure of the pressure chamber R14 increases with a relatively small increase gradient (change gradient toward the increase side). At the same time, the servo pressure also increases with a relatively small increasing gradient. At the same time, since the brake fluid is supplied from the accumulator 15b2 to the pilot chamber R11, the accumulator pressure also decreases with a relatively small decreasing gradient Z1.

Then, at time t2, the spool 15a2 becomes the pressure increasing position, and the high-pressure brake fluid is supplied from the accumulator 15b2 to the pressure chamber R14 via the high-pressure port PT13. The pressure chamber R14 communicates with the servo chamber R5, and the servo pressure starts to increase with a relatively large increasing gradient due to the accumulator pressure. At the same time, the accumulator 15b2 also supplies the brake fluid to the servo chamber R5 communicating with the pressure chamber R14, and the accumulator pressure begins to decrease with a relatively large decreasing gradient Z2. Compared with the supply of the brake fluid to the pilot chamber R11, the supply of the brake fluid to the servo chamber R5, which expands with the sliding of the first master piston 12c, consumes much more brake fluid. It can be said that the servo chamber R5 has lower rigidity (the amount of change in hydraulic pressure required to increase the unit volume) than the pilot chamber R11. Therefore, when the accumulator 15b2 and the servo chamber R5 communicate with each other, the decreasing gradient of the accumulator pressure becomes large.

The decreasing gradient Z2 is larger than the predetermined gradient, and the control switching unit 172 ends the shortening control after the time t2 and starts the normal control. That is, the control switching unit 172 determines that the spool 15a2 has reached the pressure increasing position after the decreasing gradient Z2 is calculated after the spool 15a2 reaches the pressure increasing position, and terminates the shortening control (shortening). Control OFF). In the normal control (pressure boosting control), the valve opening instruction is continuously given to the pressure boosting valve 15b7, but the flow rate of the brake fluid passing through the pressure boosting valve 15b7 per unit time is smaller than that in the shortening control. At time t3, the pressure boosting control ends according to the brake operation and shifts to the holding control, and the pressure booster valve 15b7 is closed (valve opening flag OFF).

Conventionally, the shortening control is terminated based on whether or not the servo pressure exceeds the threshold value. However, it is determined whether the increase in servo pressure is due to the spool 15a2 reaching the pressure increase position (opening range) (first factor) or the closing range due to the spool 15a2 sliding (second factor). It was difficult. That is, in the conventional control, there is a case where the shortening control is completed earlier than the target. For example, as shown by the alternate long and short dash line in FIG. 2, the servo pressure may exceed the threshold value before the time t2 is reached, and the shortening control may be terminated before the spool 15a2 reaches the pressure increasing position.

However, according to the present embodiment, attention is paid to a large change in the accumulator pressure when the servo chamber R5 and the accumulator 15b2 communicate with each other, and the cause of the increase in the servo pressure is specified by detecting the change gradient of the accumulator pressure. And the shortening control can be terminated with high accuracy. More specifically, according to the present embodiment, attention is paid to the difference in rigidity between the supply destinations of the brake fluid of the accumulator 15b2 (controlled chamber: servo chamber R5 and pilot chamber R11), and the change gradient of the accumulator pressure caused by the difference. By using the difference between the above as the end determination element, the first factor and the second factor can be separated from each other as the cause of the increase in the servo pressure, and the shortening control can be ended with high accuracy. According to the present embodiment, it is possible to suppress a decrease in responsiveness due to the shortening control being completed earlier than the target.

Further, the accumulator pressure is adjusted by the pump 15b3 so as to be equal to or higher than a predetermined lower limit value (predetermined pressure), and is maintained within a predetermined pressure range, for example, but the value at the start of pressure increase control (at the start of shortening control) is always. It is not always constant. However, in the present embodiment, since the change gradient of the accumulator pressure is used as the end determination element, the end determination can be executed regardless of the accumulator pressure at the start of the pressure increase control. The present invention is not limited to the above embodiment.

1 ... Vehicle braking device, 11 ... Brake pedal, 12 ... Master cylinder, 12a ... Master cylinder body, 12c ... First master piston, 12d ... Second master piston, 15 ... Boost mechanism, 15a ... Regulator (hydraulic pressure generation) Section), 15a1 ... Cylinder body, 15a2 ... Spool, 15b1 ... Reservoir, 15b2 ... Accumulator, 15b3 ... Pump, 15b4 ... Electric motor, 15b5 ... Pressure sensor (pressure detection section), 15b6 ... Pressure reducing valve, 15b7 ... Pressure booster valve, 16 ... Actuator, 17 ... Brake ECU, 171 ... Control unit, 172 ... Control switching unit, 8 ... Piston pressure control unit, PT13 ... High pressure port, PT14 ... Low pressure port, R1 ... First master room, R2 ... Second master room, R5 ... Servo chamber, R11 ... Piston chamber, R14 ... Pressure chamber, W ... Wheels, WC ... Wheel cylinder.

Claims (3)

A master cylinder body, a master piston sliding in the master cylinder body, and a master cylinder having a servo chamber in which a servo pressure for sliding the master piston is generated.
A cylinder body in which a high-pressure port and a low-pressure port are formed, a closed range in which both the high-pressure port and the low-pressure port are closed, and an open range in which one of the high-pressure port and the low-pressure port is closed and the other is open. A spool that can slide in the cylinder body within a sliding range including, a pilot chamber that generates a pilot pressure for sliding the spool, and a pressure that is connected to the servo chamber and whose volume changes due to the sliding of the spool. A chamber, a hydraulic pressure generating part having a chamber, and a
When the spool opens the high-pressure port and is located in the open range, a high-pressure source that supplies a hydraulic fluid having a predetermined pressure or more to the pressure chamber via the high-pressure port.
A low pressure source maintained at a pressure lower than the predetermined pressure, which is connected to the pressure chamber via the low pressure port when the spool opens the low pressure port and is located in the open range.
The unit time of the pilot pressure by the normal control is the amount of change per unit time of the pilot pressure that slides the spool in the closed range and the normal control that controls the pilot pressure according to the target value of the servo pressure. A pilot pressure control unit that executes shortening control that is larger than the amount of change per unit at different timings.
A pressure detection unit that detects the pressure of the high-voltage source,
When the change gradient on the pressure reduction side of the high voltage source detected by the pressure detection unit exceeds a predetermined gradient, the control switching unit for terminating the shortening control and the control switching unit.
A braking device for vehicles equipped with. The pilot pressure control unit includes a pressure boosting valve provided in a flow path connecting the high pressure source and the pilot chamber, a pressure reducing valve provided in the flow path connecting the low pressure source and the pilot chamber, and the pressure reducing valve. The vehicle braking device according to claim 1, further comprising a pressure boosting valve and a control unit that controls the pressure reducing valve. The high pressure source is an accumulator that accumulates brake fluid, and is configured to supply brake fluid from a pump driven by an electric motor when the detection result of the pressure detection unit becomes less than the predetermined pressure. The vehicle braking device according to 1 or 2.

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