JP5999118B2 - Braking device for vehicle - Google Patents

Description

  The present invention relates to a vehicle braking device.

  As a vehicle braking device, for example, a master cylinder, an output piston that is driven by a force corresponding to the hydraulic pressure in the servo chamber and changes the volume of the master chamber, and a first filled with brake fluid are filled between the output pistons. An input piston that divides the fluid pressure chamber and interlocks with the operation of the brake operation member, a mechanical servo pressure generator that outputs fluid pressure corresponding to the fluid pressure input to the pilot chamber to the servo chamber, and And a pilot pressure generating section that generates a hydraulic pressure corresponding to the control signal in the pilot chamber. Such a brake device for vehicles is described in JP, 2011-240873, A.

  Japanese Patent Application Laid-Open No. 2013-193619 discloses a mechanical regulator that generates a hydraulic pressure in the servo chamber based on an accumulator pressure in an accumulator as a mechanical servo pressure generator.

  As described above, some vehicle braking devices include a pressure adjusting device that outputs a servo pressure corresponding to the pilot pressure input to the pilot chamber to the servo chamber. Basically, the pressure regulator has a piston driven by the difference between the force corresponding to the pilot pressure and the force corresponding to the servo pressure, and the volume of the pilot chamber changes as the piston moves. .

JP 2011-240873 A JP 2013-193619 A

  Here, the inventor has found a point (problem) to be further improved in a braking device including a pressure regulator. That is, when the actual flow rate of the servo pressure almost reaches the target pressure, the flow rate of the liquid flowing into and out of the pilot chamber is controlled to zero (holding control to maintain the servo pressure), and then the flow rate is reduced to zero. Regardless, the piston moves and an overshoot or undershoot occurs in which the actual servo pressure deviates from the target pressure. This amount of change in servo pressure (hysteresis amount) is unique to the pressure regulator. In a vehicle braking device including a pressure regulator, there is room for improvement in the accuracy of brake control.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vehicular braking apparatus that can acquire a hysteresis amount and can perform brake control based on the hysteresis amount.

  A vehicle braking device according to an aspect 1 of the present invention includes a pressure regulator that outputs a servo pressure corresponding to a pilot pressure input to a pilot chamber to the servo chamber, and a high pressure source that accumulates a predetermined range of fluid pressure. A low pressure source in which a hydraulic pressure lower than the hydraulic pressure accumulated in the high pressure source is accumulated, a pressure increasing solenoid valve that adjusts the flow rate of the liquid that flows into the pilot chamber from the high pressure source, and A depressurizing solenoid valve for adjusting a flow rate of liquid flowing out from a pilot chamber to the low pressure source, wherein the servo pressure is controlled by controlling the depressurizing solenoid valve and the depressurizing solenoid valve. After changing from a predetermined starting pressure with a predetermined pressure gradient, when the servo pressure exceeds a predetermined value, the pressure increasing solenoid valve and the pressure reducing solenoid valve are closed, and the pressure increasing solenoid valve and the pressure reducing solenoid valve are closed. After closing the solenoid valve A hysteresis amount acquisition unit that executes a hysteresis amount acquisition process for acquiring the amount of change in servo pressure as a hysteresis amount corresponding to the start pressure; and the solenoid valve for pressure increase and the solenoid valve for pressure reduction based on the hysteresis amount And a control unit for controlling.

  According to this configuration, the actual hysteresis amount for a certain starting pressure can be acquired. Then, brake control can be performed with higher accuracy by performing brake control based on the acquired hysteresis amount.

  In the vehicle braking device according to aspect 2 of the present invention, in the aspect 1, the hysteresis amount acquiring unit changes the servo pressure with the pressure gradient at the same level from the different start pressures to obtain a plurality of hysteresis amounts. And a characteristic deriving unit for deriving a characteristic of the hysteresis amount with respect to the start pressure based on the plurality of hysteresis amounts obtained by the hysteresis amount obtaining unit, and the control unit includes the characteristic of the hysteresis amount. The pressure increasing solenoid valve and the pressure reducing solenoid valve are controlled based on the above.

  According to this configuration, a plurality of hysteresis amounts with different starting pressures and the same level of gradient can be acquired. Based on the acquired actual hysteresis amount, a hysteresis amount characteristic (hysteresis characteristic) with respect to the start pressure (servo pressure) can be obtained. By using the hysteresis characteristic for brake control, the accuracy of the brake control is further improved.

  In the vehicle braking apparatus according to aspect 3 of the present invention, in the aspect 2, the hysteresis amount acquisition unit closes the pressure reducing electromagnetic valve and acquires the pressure increasing electromagnetic valve so as to acquire a plurality of hysteresis amounts. And increasing the servo pressure with a predetermined pressure increase gradient, and then closing the pressure increasing solenoid valve to obtain the hysteresis amount corresponding to the start pressure of the servo pressure. The amount acquisition process is executed continuously.

  Further, in the vehicle braking apparatus according to aspect 4 of the present invention, in aspect 2 or 3, the hysteresis amount acquisition unit closes the pressure increasing electromagnetic valve and acquires the plurality of hysteresis amounts. After increasing the opening of the pressure reducing solenoid valve to reduce the servo pressure with a predetermined pressure reducing gradient, the pressure reducing solenoid valve is closed to obtain the hysteresis amount corresponding to the starting pressure of the servo pressure. The hiss amount acquisition process to be executed is continuously executed.

  According to the above aspects 3 and 4, the time for acquiring a plurality of hysteresis amounts due to a plurality of starting pressures can be shortened by continuously performing the hysteresis amount acquiring process. In addition, by executing the hysteresis amount acquisition process continuously in a short time, multiple hysteresis amounts can be acquired in the same environment (with almost no temperature change), and variations due to the environment are suppressed, resulting in hysteresis characteristics Improves accuracy.

  The vehicle braking device according to aspect 5 of the present invention is the vehicle braking apparatus according to any one of aspects 1 to 4, wherein the pressure adjusting device depends on a difference between a force corresponding to the pilot pressure and a force corresponding to the servo pressure. A piston that is driven, and when the volume of the pilot chamber changes as the piston moves, and the flow rate of the liquid flowing into and out of the pilot chamber increases, the force corresponding to the pilot pressure and the servo pressure The movement amount of the piston relative to the position of the piston in an equilibrium state in which the corresponding force is balanced is increased, and the flow rate of the liquid flowing into and out of the servo chamber is increased, and the amount of hiss The acquisition unit gradually increases or decreases the servo pressure when the servo pressure is changed from the predetermined start pressure with the predetermined pressure gradient.

  The hysteresis amount includes a pressure-dependent component (component depending on the servo pressure) due to the sliding resistance of the piston and a volume change component (piston stroke component) of the pilot chamber. It can be said that the pressure-dependent component is a sliding resistance component. According to the above aspect 5, by controlling the pilot pressure so that the servo pressure is gradually increased or decreased, the volume change amount (piston of the piston chamber) when the servo pressure exceeds a predetermined value in the hysteresis amount acquisition process. (Stroke amount) can be made minute. That is, the volume change component (stroke component) in the acquired hysteresis amount can be reduced to a negligible level, and a pressure-dependent component (sliding resistance component) that is a characteristic unique to the pressure regulator can be derived.

  The vehicle braking apparatus according to aspect 6 of the present invention is the vehicle braking apparatus according to any one of aspects 1 to 5, wherein the hysteresis amount acquiring unit includes the pressure increasing solenoid valve and the pressure reducing solenoid valve in the hysteresis amount acquiring process. And controlling the other control current of the pressure increasing solenoid valve and the pressure reducing solenoid valve to a closed state. From the current value to the intermediate value that is closer to the valve closing side than the valve opening current value and to the valve opening side than the current value in the closed state. The servo pressure is changed at the predetermined pressure gradient by changing the valve opening side with a small second gradient.

  According to this configuration, by making the first gradient larger than the second gradient, it is possible to reach the intermediate value before the opening of the solenoid valve in a short time, and the time for the hysteresis amount acquisition process can be shortened. it can. In addition, by making the second gradient smaller than the first gradient, it is possible to suppress the magnitude and variation of the capacity change component when the solenoid valve is opened, and the accuracy of the hysteresis amount acquisition process is improved.

  The vehicle braking apparatus according to aspect 7 of the present invention is the vehicle braking apparatus according to any one of aspects 1 to 6, wherein the hysteresis amount acquiring unit includes the pressure increasing solenoid valve and the pressure reducing solenoid valve in the hysteresis amount acquiring process. And controlling the other control current of the pressure-increasing solenoid valve and the pressure-reducing solenoid valve to a constant current gradient. To change the servo pressure with the predetermined pressure gradient.

  According to this configuration, a control current having a predetermined constant gradient is supplied to the solenoid valve without using a control current by feedback control performed by looking at the actual servo pressure. Thereby, the reversal of the transient pressure relationship between the pilot chamber and the servo chamber can be suppressed, and the direction of the force applied to the pilot chamber can be stabilized. That is, the accuracy of the amount of hysteresis that is earned is improved.

  The vehicle braking apparatus according to aspect 8 of the present invention is the vehicle braking apparatus according to any one of aspects 1 to 7, wherein the control unit is configured to obtain a plurality of hysteresis amounts acquired by the hysteresis amount acquisition unit in a state where the brake temperature is at the same level. The pressure increasing solenoid valve and the pressure reducing solenoid valve are controlled based on the hysteresis amount.

  According to this configuration, by using a plurality of hysteresis amounts acquired when the temperature of the braking device (for example, the brake fluid temperature) is the same level in the brake control or the derivation of the hysteresis characteristic, the variation in value due to the temperature can be achieved. It can be suppressed. That is, accurate brake control or hysteresis characteristics can be derived.

  The braking device for a vehicle according to aspect 9 of the present invention includes a temperature determination unit that determines whether or not the temperature of the brake fluid is stable in aspect 8 above, and the hysteresis amount acquisition unit is controlled by the temperature determination unit. A plurality of the hysteresis amounts are acquired while it is determined that the temperature of the brake fluid is stable.

  According to this configuration, since the plurality of hysteresis amounts are acquired when the temperature of the brake fluid is stable, the occurrence of variations due to the temperature of the brake fluid can be suppressed, and the plurality of hysteresis amounts can be acquired with high accuracy. Then, by controlling the solenoid valve based on an accurate hysteresis amount, it is possible to perform an accurate brake control.

It is a block diagram which shows the structure of the vehicle braking device of 1st embodiment. It is sectional drawing which shows the detailed structure of the regulator of 1st embodiment. It is a time chart for demonstrating the hysteresis amount acquisition process of 1st embodiment. It is a flowchart for demonstrating the hysteresis amount acquisition process of 1st embodiment. It is a time chart for demonstrating the hysteresis amount acquisition process of 1st embodiment. It is explanatory drawing for demonstrating the hysteresis characteristic of 1st embodiment. It is a time chart for demonstrating the hysteresis amount acquisition process of 2nd embodiment. It is a time chart for demonstrating the hysteresis amount acquisition process of 2nd embodiment. It is a block diagram which shows the structure of the brake device for vehicles of 3rd embodiment.

  Hereinafter, a braking device according to an embodiment of the present invention will be described with reference to the drawings. In each drawing used for explanation, the shape and size of each part may not necessarily be exact.

<First embodiment>
As shown in FIG. 1, the braking device includes a hydraulic braking force generator BF that generates hydraulic braking force on the wheels 5FR, 5FL, 5RR, and 5RL, and a brake ECU (“control unit”) that controls the hydraulic braking force generator BF. 6).

(Hydraulic braking force generator BF)
The hydraulic braking force generation device BF includes a master cylinder 1, a reaction force generation device 2, a first control valve 22, a second control valve 23, a servo pressure generation device 4, a hydraulic pressure control unit 5, and various sensors. 71-76 and the like.

(Master cylinder 1)
The master cylinder 1 is a part that supplies hydraulic fluid to the hydraulic pressure control unit 5 in accordance with the operation amount of the brake pedal 10, and includes a main cylinder 11, a cover cylinder 12, an input piston 13, a first master piston 14, and a second master piston 1. It is comprised by the master piston 15 grade | etc.,. The brake pedal 10 may be any brake operating means that allows the driver to operate the brake. Moreover, the number of master pistons may be one.

  The main cylinder 11 is a bottomed, substantially cylindrical housing that is closed at the front and opens to the rear. An inner wall 111 that protrudes in an inward flange shape is provided near the rear of the inner periphery of the main cylinder 11. The center of the inner wall 111 is a through hole 111a that penetrates in the front-rear direction. Further, small-diameter portions 112 (rear) and 113 (front) whose inner diameter is slightly smaller are provided in front of the inner wall 111 inside the main cylinder 11. That is, the small diameter portions 112 and 113 project inwardly from the inner peripheral surface of the main cylinder 11. A first master piston 14 is disposed in the main cylinder 11 so as to be slidable in contact with the small diameter portion 112 and movable in the axial direction. Similarly, the second master piston 15 is disposed so as to be slidable in contact with the small diameter portion 113 and movable in the axial direction.

  The cover cylinder 12 includes a substantially cylindrical cylinder portion 121, a bellows cylindrical boot 122, and a cup-shaped compression spring 123. The cylinder part 121 is disposed on the rear end side of the main cylinder 11 and is coaxially fitted in the opening on the rear side of the main cylinder 11. The inner diameter of the front part 121 a of the cylinder part 121 is set larger than the inner diameter of the through hole 111 a of the inner wall part 111. Further, the inner diameter of the rear part 121b of the cylinder part 121 is made smaller than the inner diameter of the front part 121a.

  The dust-proof boot 122 has a bellows-like shape and can be expanded and contracted in the front-rear direction, and is assembled so as to be in contact with the rear end side opening of the cylinder part 121 on the front side. A through hole 122 a is formed in the center of the rear of the boot 122. The compression spring 123 is a coil-shaped urging member disposed around the boot 122, and the front side thereof is in contact with the rear end of the main cylinder 11, and the rear side is compressed so as to be close to the through hole 122 a of the boot 122. It is a diameter. The rear end of the boot 122 and the rear end of the compression spring 123 are coupled to the operation rod 10a. The compression spring 123 biases the operation rod 10a backward.

  The input piston 13 is a piston that slides in the cover cylinder 12 in accordance with the operation of the brake pedal 10. The input piston 13 is a bottomed substantially cylindrical piston having a bottom surface at the front and an opening at the rear. The bottom wall 131 constituting the bottom surface of the input piston 13 has a larger diameter than other portions of the input piston 13. The input piston 13 is axially slidable and liquid-tightly arranged at the rear part 121 b of the cylinder part 121, and the bottom wall 131 enters the inner peripheral side of the front part 121 a of the cylinder part 121.

  Inside the input piston 13, an operation rod 10 a that is linked to the brake pedal 10 is disposed. The pivot 10b at the tip of the operation rod 10a can push the input piston 13 forward. The rear end of the operation rod 10 a protrudes outside through the opening on the rear side of the input piston 13 and the through hole 122 a of the boot 122, and is connected to the brake pedal 10. When the brake pedal 10 is depressed, the operation rod 10a moves forward while pushing the boot 122 and the compression spring 123 in the axial direction. As the operating rod 10a moves forward, the input piston 13 also moves forward.

  The first master piston 14 is disposed on the inner wall 111 of the main cylinder 11 so as to be slidable in the axial direction. The first master piston 14 is formed integrally with a pressurizing cylinder portion 141, a flange portion 142, and a protruding portion 143 in order from the front side. The pressure cylinder 141 is formed in a substantially cylindrical shape with a bottom having an opening on the front, has a gap with the inner peripheral surface of the main cylinder 11, and is in sliding contact with the small-diameter portion 112. A coil spring-like urging member 144 is disposed in the internal space of the pressure cylinder portion 141 between the second master piston 15. The first master piston 14 is urged rearward by the urging member 144. In other words, the first master piston 14 is urged by the urging member 144 toward the set initial position.

  The flange portion 142 has a larger diameter than the pressure cylinder portion 141 and is in sliding contact with the inner peripheral surface of the main cylinder 11. The protruding portion 143 has a smaller diameter than the flange portion 142 and is disposed so as to slide in a liquid-tight manner in the through hole 111 a of the inner wall portion 111. The rear end of the protruding portion 143 passes through the through hole 111 a and protrudes into the internal space of the cylinder portion 121 and is separated from the inner peripheral surface of the cylinder portion 121. The rear end surface of the protrusion 143 is separated from the bottom wall 131 of the input piston 13, and the separation distance d can be changed.

  Here, the “first master chamber 1 </ b> D” is defined by the inner peripheral surface of the main cylinder 11, the front side of the pressure cylinder portion 141 of the first master piston 14, and the rear side of the second master piston 15. Further, the rear chamber behind the first master chamber 1D is defined by the inner peripheral surface (inner peripheral portion) of the main cylinder 11, the small-diameter portion 112, the front surface of the inner wall portion 111, and the outer peripheral surface of the first master piston 14. ing. The front end portion and the rear end portion of the flange portion 142 of the first master piston 14 divide the rear chamber into the front and rear, the “second hydraulic chamber 1C” is partitioned on the front side, and the “servo chamber (“ output ” 1A ”corresponding to“ chamber ”is partitioned. Furthermore, the inner peripheral part of the main cylinder 11, the rear surface of the inner wall part 111, the inner peripheral surface (inner peripheral part) of the front part 121a of the cylinder part 121, the protrusion part 143 (rear end part) of the first master piston 14, and the input A “first hydraulic chamber 1 </ b> B” is defined by the front end portion of the piston 12.

  The second master piston 15 is disposed on the front side of the first master piston 14 in the main cylinder 11 so as to be in sliding contact with the small diameter portion 113 and movable in the axial direction. The second master piston 15 is integrally formed with a cylindrical pressure cylinder portion 151 having an opening in the front and a bottom wall 152 that closes the rear side of the pressure cylinder portion 151. The bottom wall 152 supports the biasing member 144 between the first master piston 14. A coil spring-like urging member 153 is disposed in the internal space of the pressure cylinder portion 151 between the inner bottom surface 111d of the main cylinder 11 closed. The second master piston 15 is urged rearward by the urging member 153. In other words, the second master piston 15 is biased by the biasing member 153 toward the set initial position. A “second master chamber 1 </ b> E” is defined by the inner peripheral surface of the main cylinder 11, the inner bottom surface 111 d, and the second master piston 15.

  The master cylinder 1 is formed with ports 11a to 11i that allow communication between the inside and the outside. The port 11 a is formed behind the inner wall 111 in the main cylinder 11. The port 11b is formed opposite to the port 11a at the same position in the axial direction as the port 11a. The port 11 a and the port 11 b communicate with each other via an annular space between the inner peripheral surface of the main cylinder 11 and the outer peripheral surface of the cylinder part 121. The port 11 a and the port 11 b are connected to the pipe 161 and to the reservoir 171.

  The port 11 b communicates with the first hydraulic chamber 1 </ b> B through a passage 18 formed in the cylinder portion 121 and the input piston 13. The passage 18 is shut off when the input piston 13 moves forward, whereby the first hydraulic chamber 1B and the reservoir 171 are shut off.

  The port 11c is formed behind the inner wall 111 and in front of the port 11a, and allows the first hydraulic chamber 1B and the pipe 162 to communicate with each other. The port 11d is formed in front of the port 11c, and communicates the servo chamber 1A and the pipe 163. The port 11e is formed in front of the port 11d and communicates the second hydraulic chamber 1C and the pipe 164.

  The port 11 f is formed between the seal members 91 and 92 of the small diameter portion 112, and communicates the reservoir 172 and the inside of the main cylinder 11. The port 11 f communicates with the first master chamber 1 </ b> D via a passage 145 formed in the first master piston 14. The passage 145 is formed at a position where the port 11f and the first master chamber 1D are blocked when the first master piston 14 moves forward. The port 11g is formed in front of the port 11f, and connects the first master chamber 1D and the pipe 51.

  The port 11 h is formed between the seal members 93 and 94 of the small diameter portion 113 and communicates the reservoir 173 and the inside of the main cylinder 11. The port 11 h communicates with the second master chamber 1 </ b> E via a passage 154 formed in the pressure cylinder portion 151 of the second master piston 15. The passage 154 is formed at a position where the port 11h and the second master chamber 1E are blocked when the second master piston 15 moves forward. The port 11i is formed in front of the port 11h, and communicates the second master chamber 1E and the pipe 52.

  Further, in the master cylinder 1, a seal member (black circle portion in the drawing) such as an O-ring is appropriately disposed. The seal members 91 and 92 are disposed in the small diameter portion 112 and are in liquid-tight contact with the outer peripheral surface of the first master piston 14. Similarly, the seal members 93 and 94 are disposed in the small-diameter portion 113 and are in liquid-tight contact with the outer peripheral surface of the second master piston 15. Seal members 95 and 96 are also arranged between the input piston 13 and the cylinder part 121.

  The stroke sensor 71 is a sensor that detects an operation amount (stroke amount) by which the brake pedal 10 is operated by the driver, and transmits a detection signal to the brake ECU 6. The brake stop switch 72 is a switch that detects whether or not the brake pedal 10 is operated by the driver using a binary signal, and transmits a detection signal to the brake ECU 6.

(Reaction force generator 2)
The reaction force generator 2 is a device that generates a reaction force that opposes the operation force when the brake pedal 10 is operated, and is configured mainly with a stroke simulator 21. The stroke simulator 21 generates reaction force hydraulic pressure in the first hydraulic pressure chamber 1B and the second hydraulic pressure chamber 1C according to the operation of the brake pedal 10. The stroke simulator 21 is configured such that a piston 212 is slidably fitted to a cylinder 211. The piston 212 is urged forward by a compression spring 213, and a reaction force hydraulic chamber 214 is formed on the front side of the piston 212. The reaction force hydraulic chamber 214 is connected to the second hydraulic chamber 1C via the pipe 164 and the port 11e, and the reaction force hydraulic chamber 214 is connected to the first control valve 22 and the second control via the pipe 164. Connected to the valve 23.

(First control valve 22)
The first control valve 22 is an electromagnetic valve having a structure that is closed in a non-energized state, and opening / closing thereof is controlled by the brake ECU 6. The first control valve 22 is connected between the pipe 164 and the pipe 162. Here, the pipe 164 communicates with the second hydraulic chamber 1C via the port 11e, and the pipe 162 communicates with the first hydraulic chamber 1B via the port 11c. When the first control valve 22 is opened, the first hydraulic chamber 1B is opened, and when the first control valve 22 is closed, the first hydraulic chamber 1B is sealed. Accordingly, the pipe 164 and the pipe 162 are provided so as to communicate the first hydraulic chamber 1B and the second hydraulic chamber 1C.

  The first control valve 22 is closed in a non-energized state where no current is supplied. At this time, the first hydraulic chamber 1B and the second hydraulic chamber 1C are shut off. As a result, the first hydraulic pressure chamber 1B is hermetically sealed and there is no place for the hydraulic fluid, and the input piston 13 and the first master piston 14 are interlocked with each other while maintaining a constant separation distance d. In addition, the first control valve 22 is opened in the energized state when energized, and at this time, the first hydraulic chamber 1B and the second hydraulic chamber 1C are communicated. Thereby, the volume change of the 1st hydraulic pressure chamber 1B and the 2nd hydraulic pressure chamber 1C accompanying the advance / retreat of the 1st master piston 14 is absorbed by the movement of hydraulic fluid.

  The pressure sensor 73 is a sensor that detects the reaction force hydraulic pressure in the second hydraulic chamber 1 </ b> C and the first hydraulic chamber 1 </ b> B, and is connected to the pipe 164. The pressure sensor 73 detects the pressure of the second hydraulic pressure chamber 1C when the first control valve 22 is closed, and communicates with the first hydraulic pressure chamber 1B communicated when the first control valve 22 is open. It will also detect the pressure. The pressure sensor 73 transmits a detection signal to the brake ECU 6.

(Second control valve 23)
The second control valve 23 is an electromagnetic valve having a structure that opens in a non-energized state, and opening / closing is controlled by the brake ECU 6. The second control valve 23 is connected between the pipe 164 and the pipe 161. Here, the pipe 164 communicates with the second hydraulic chamber 1C through the port 11e, and the pipe 161 communicates with the reservoir 171 through the port 11a. Therefore, the second control valve 23 communicates between the second hydraulic pressure chamber 1C and the reservoir 171 in a non-energized state and does not generate a reaction force hydraulic pressure, but shuts off in an energized state and generates a reaction force hydraulic pressure. Let

(Servo pressure generator 4)
The servo pressure generator 4 includes a pressure reducing valve (corresponding to a “pressure reducing solenoid valve”) 41, a pressure increasing valve (corresponding to a “pressure increasing solenoid valve”) 42, a pressure supply unit 43, a regulator 44, and the like. Yes. The pressure reducing valve 41 is an electromagnetic valve having a structure that opens in a non-energized state, and the flow rate is controlled by the brake ECU 6. One side of the pressure reducing valve 41 is connected to the pipe 161 via the pipe 411, and the other side of the pressure reducing valve 41 is connected to the pipe 413. That is, one side of the pressure reducing valve 41 communicates with the reservoir (corresponding to “low pressure source”) 171 through the pipes 411 and 161 and the ports 11a and 11b. Note that the pipe 411 may be connected to a reservoir 434 described later instead of the reservoir 171. In this case, the reservoir 434 corresponds to a low pressure source. Further, the reservoir 171 and the reservoir 434 may be the same reservoir.

  The pressure increasing valve 42 is an electromagnetic valve having a structure that is closed in a non-energized state, and the flow rate is controlled by the brake ECU 6. One of the pressure increasing valves 42 is connected to the pipe 421, and the other of the pressure increasing valves 42 is connected to the pipe 422. The pressure reducing valve 41 and the pressure increasing valve 42 correspond to a pilot hydraulic pressure generating device.

  The pressure supply unit 43 is a part that mainly supplies high-pressure hydraulic fluid to the regulator 44. The pressure supply unit 43 includes an accumulator (corresponding to a “high pressure source”) 431, a hydraulic pump 432, a motor 433, a reservoir 434, and the like.

  The accumulator 431 is a tank that accumulates high-pressure hydraulic fluid. The accumulator 431 is connected to the regulator 44 and the hydraulic pump 432 by a pipe 431a. The hydraulic pump 432 is driven by the motor 433 and pumps the hydraulic fluid stored in the reservoir 434 to the accumulator 431. The pressure sensor 75 provided in the pipe 431a detects the accumulator hydraulic pressure of the accumulator 431, and transmits a detection signal to the brake ECU 6. The accumulator hydraulic pressure correlates with the accumulated amount of hydraulic fluid accumulated in the accumulator 431.

  When the pressure sensor 75 detects that the accumulator hydraulic pressure has dropped below a predetermined value, the motor 433 is driven based on a command from the brake ECU 6. As a result, the hydraulic pump 432 pumps the hydraulic fluid to the accumulator 431 and recovers the accumulator hydraulic pressure to a predetermined value or higher.

  As shown in FIG. 2, the regulator (corresponding to “pressure regulator”) 44 includes a cylinder 441, a ball valve 442, an urging unit 443, a valve seat 444, a control piston (corresponding to “piston”) 445, And a sub piston 446 and the like.

  The cylinder 441 includes a substantially bottomed cylindrical cylinder case 441a having a bottom surface on one side (right side in the drawing) and a lid member 441b that closes an opening (left side in the drawing) of the cylinder case 441a. The cylinder case 441a is formed with a plurality of ports 4a to 4h for communicating the inside and the outside. The lid member 441b is also formed in a substantially bottomed cylindrical shape, and each port is formed in each part facing the plurality of ports 4a to 4h of the cylindrical part.

  The port 4a is connected to the pipe 431a. The port 4b is connected to the pipe 422. The port 4 c is connected to the pipe 163. The pipe 163 connects the servo chamber 1A and the output port 4c. The port 4d is connected to the pipe 161 via the pipe 414. The port 4 e is connected to the pipe 424 and further connected to the pipe 422 via the relief valve 423. The port 4f is connected to the pipe 413. The port 4g is connected to the pipe 421. The port 4 h is connected to a pipe 511 branched from the pipe 51. Note that the pipe 414 may be connected to the reservoir 434 instead of the pipe 161.

  The ball valve 442 is a ball type valve and is disposed on the bottom surface side of the cylinder case 441a inside the cylinder 441 (hereinafter also referred to as the cylinder bottom surface side). The urging portion 443 is a spring member that urges the ball valve 442 toward the opening side of the cylinder case 441a (hereinafter also referred to as the cylinder opening side), and is installed on the bottom surface of the cylinder case 441a. The valve seat portion 444 is a wall member provided on the inner peripheral surface of the cylinder case 441a, and partitions the cylinder opening side and the cylinder bottom surface side. A through passage 444 a is formed in the center of the valve seat portion 444 to communicate the partitioned cylinder opening side and cylinder bottom side. The valve member 444 holds the ball valve 442 from the cylinder opening side in such a manner that the biased ball valve 442 closes the through passage 444a. A valve seat surface 444b on which the ball valve 442 is detachably seated (contacted) is formed in the opening on the cylinder bottom surface side of the through passage 444a.

  A space defined by the ball valve 442, the urging portion 443, the valve seat portion 444, and the inner peripheral surface of the cylinder case 441a on the cylinder bottom surface side is referred to as a “first chamber 4A”. The first chamber 4A is filled with hydraulic fluid, connected to the pipe 431a via the port 4a, and connected to the pipe 422 via the port 4b.

  The control piston 445 includes a substantially columnar main body 445a and a substantially cylindrical protrusion 445b having a smaller diameter than the main body 445a. In the cylinder 441, the main body 445a is disposed on the cylinder opening side of the valve seat 444 so as to be slidable in the axial direction in a coaxial and liquid-tight manner. The main body 445a is biased toward the cylinder opening by a biasing member (not shown). A passage 445c extending in the radial direction (vertical direction in the drawing) with both ends opened to the peripheral surface of the main body 445a is formed at the approximate center of the main body 445a in the cylinder axis direction. A part of the inner peripheral surface of the cylinder 441 corresponding to the opening position of the passage 445c has a port 4d and is recessed in a concave shape. This hollow space is referred to as “third chamber 4C”.

  The protruding portion 445b protrudes from the center of the cylinder bottom end surface of the main body portion 445a toward the cylinder bottom surface. The diameter of the protruding portion 445 b is smaller than the through passage 444 a of the valve seat portion 444. The protruding portion 445b is arranged coaxially with the through passage 444a. The tip of the protrusion 445b is spaced from the ball valve 442 toward the cylinder opening by a predetermined distance. The protrusion 445b is formed with a passage 445d that extends in the cylinder axial direction and opens in the center of the cylinder bottom end surface of the protrusion 445b. The passage 445d extends into the main body 445a and is connected to the passage 445c.

  The space defined by the cylinder bottom end surface of the main body 445a, the outer peripheral surface of the protrusion 445b, the inner peripheral surface of the cylinder 441, the valve seat 444, and the ball valve 442 is referred to as a “second chamber 4B”. The second chamber 4B communicates with the ports 4d and 4e via the passages 445d and 445c and the third chamber 4C in a state where the protruding portion 445b and the ball valve 442 are not in contact with each other.

  The sub piston 446 includes a sub main body 446a, a first protrusion 446b, and a second protrusion 446c. The sub main body 446a is formed in a substantially cylindrical shape. In the cylinder 441, the sub main body 446a is disposed coaxially, liquid-tightly, and slidable in the axial direction on the cylinder opening side of the main body 445a.

  The first projecting portion 446b has a substantially cylindrical shape having a smaller diameter than the sub main body portion 446a, and projects from the center of the end surface of the sub main body portion 446a on the cylinder bottom surface side. The first protrusion 446b is in contact with the cylinder opening side end surface of the main body 445a. The 2nd protrusion part 446c is the same shape as the 1st protrusion part 446b, and protrudes from the end surface center by the side of the cylinder opening of the sub main-body part 446a. The second protrusion 446c is in contact with the lid member 441b.

  A space defined by the end surface on the cylinder bottom surface side of the sub main body portion 446a, the outer peripheral surface of the first projecting portion 446b, the end surface on the cylinder opening side of the control piston 445, and the inner peripheral surface of the cylinder 441 is referred to as “first pilot chamber (“ 4D ”corresponding to the“ pilot room ”. The first pilot chamber 4D communicates with the pressure reducing valve 41 through the port 4f and the pipe 413, and communicates with the pressure increasing valve 42 through the port 4g and the pipe 421.

  On the other hand, a space defined by the end face on the cylinder opening side of the sub main body 446a, the outer peripheral surface of the second projecting portion 446c, the lid member 441b, and the inner peripheral surface of the cylinder 441 is referred to as a “second pilot chamber 4E”. The second pilot chamber 4E communicates with the port 11g through the port 4h and the pipes 511 and 51. Each chamber 4A-4E is filled with hydraulic fluid. The pressure sensor 74 is a sensor that detects the servo pressure supplied to the servo chamber 1 </ b> A, and is connected to the pipe 163. The pressure sensor 74 transmits a detection signal to the brake ECU 6.

  Thus, the regulator 44 has the control piston 445 that is driven by the difference between the force corresponding to the pressure in the first pilot chamber 4D (also referred to as “pilot pressure”) and the force corresponding to the servo pressure. When the volume of the first pilot chamber 4D changes with the movement of 445 and the flow rate of the liquid flowing into and out of the first pilot chamber 4D increases, the force corresponding to the pilot pressure and the force corresponding to the servo pressure are balanced. The amount of movement of the control piston 445 relative to the position of the control piston 445 in the equilibrium state is increased, and the flow rate of the liquid flowing into and out of the servo chamber 1A is increased.

  As the flow rate of the liquid flowing from the accumulator 431 to the first pilot chamber 4D increases, the regulator 44 expands the first pilot chamber 4D and increases the flow rate of the liquid flowing from the accumulator 431 to the servo chamber 1A. As the flow rate of the liquid flowing out from the pilot chamber 4D to the reservoir 171 increases, the first pilot chamber 4D shrinks and the flow rate of the liquid flowing out from the servo chamber 1A to the reservoir 171 increases.

  Further, the control piston 445 has a damper device Z on a wall portion facing the first pilot chamber 4D. The damper device Z is configured like a stroke simulator, and has a piston portion that is biased toward the first pilot chamber 4D by a biasing member. By providing the damper device Z, the rigidity of the first pilot chamber 4D changes according to the pilot pressure.

(Hydraulic pressure control unit 5)
Wheel cylinders 541 to 544 communicate with the first master chamber 1D and the second master chamber 1E that generate master cylinder hydraulic pressure (master pressure) via pipes 51 and 52 and an ABS (Antilock Break System) 53. . The wheel cylinders 541 to 544 constitute a brake for the wheels 5FR to 5RL. Specifically, a known ABS 53 is connected to the port 11g of the first master chamber 1D and the port 11i of the second master chamber 1E via pipes 51 and 52, respectively. Wheel cylinders 541 to 544 for operating brakes for braking the wheels 5FR to 5RL are connected to the ABS 53.

  The ABS 53 includes a wheel speed sensor 76 that detects a wheel speed. A detection signal indicating the wheel speed detected by the wheel speed sensor 76 is output to the brake ECU 6.

  In the ABS 53 configured in this way, the brake ECU 6 switches and controls the opening and closing of each holding valve and the pressure reducing valve based on the master pressure, the state of the wheel speed, and the longitudinal acceleration, and operates the motor as necessary. ABS control (anti-lock brake control) is performed to adjust the brake fluid pressure applied to the wheel cylinders 541 to 544, that is, the braking force applied to the wheels 5FR to 5RL. The ABS 53 is a device that supplies the hydraulic fluid supplied from the master cylinder 1 to the wheel cylinders 541 to 544 after adjusting the amount and timing based on an instruction from the brake ECU 6.

  In “brake control” to be described later, the hydraulic pressure sent from the accumulator 431 of the servo pressure generating device 4 is controlled by the pressure increasing valve 42 and the pressure reducing valve 41 to generate servo pressure in the servo chamber 1A. 14 and the second master piston 15 move forward to pressurize the first master chamber 1D and the second master chamber 1E. The hydraulic pressures in the first master chamber 1D and the second master chamber 1E are supplied as master pressure from the ports 11g and 11i to the wheel cylinders 541 to 544 via the pipes 51 and 52 and the ABS 53, and hydraulic braking force is applied to the wheels 5FR to 5RL. Is granted.

(Brake ECU 6)
The brake ECU 6 is an electronic control unit and has a microcomputer. The microcomputer includes a storage unit such as an input / output interface, a CPU, a RAM, a ROM, and a non-volatile memory connected to each other via a bus.

  The brake ECU 6 is connected to various sensors 71 to 76 in order to control the electromagnetic valves 22, 23, 41, 42, the motor 433, and the like. The brake ECU 6 receives an operation amount (stroke amount) of the brake pedal 10 by the driver from the stroke sensor 71, and inputs whether the driver has operated the brake pedal 10 from the brake stop switch 72. The reaction force hydraulic pressure of the two fluid pressure chamber 1C or the pressure (or reaction force fluid pressure) of the first fluid pressure chamber 1B is input, the servo pressure supplied from the pressure sensor 74 to the servo chamber 1A is input, and the pressure sensor 75 The accumulator hydraulic pressure of the accumulator 431 is input from, and the speeds of the wheels 5FR, 5FL, 5RR, 5RL are input from the wheel speed sensor 76.

(Brake control)
Here, the brake control of the brake ECU 6 will be described. The brake control is normal brake control. That is, the brake ECU 6 energizes the first control valve 22 to open, and energizes the second control valve 23 to close the valve. When the second control valve 23 is closed, the second hydraulic chamber 1C and the reservoir 171 are shut off, and when the first control valve 22 is opened, the first hydraulic chamber 1B and the second hydraulic chamber are opened. 1C communicates. In this way, the brake control controls the servo pressure in the servo chamber 1A by controlling the pressure reducing valve 41 and the pressure increasing valve 42 with the first control valve 22 opened and the second control valve 23 closed. It is a mode to do. It can be said that the pressure reducing valve 41 and the pressure increasing valve 42 are valve devices that adjust the flow rate of the hydraulic fluid flowing into and out of the first pilot chamber 4D. In this brake control, the brake ECU 6 calculates the “request braking force” of the driver from the operation amount of the brake pedal 10 (the movement amount of the input piston 13) detected by the stroke sensor 72 or the operation force of the brake pedal 10. .

  More specifically, when the brake pedal 10 is not depressed, the state as described above, that is, the ball valve 442 closes the through passage 444a of the valve seat portion 444. Further, the pressure reducing valve 41 is in an open state, and the pressure increasing valve 42 is in a closed state. That is, the first chamber 4A and the second chamber 4B are isolated.

  The second chamber 4B communicates with the servo chamber 1A via the pipe 163 and is kept at the same pressure. The second chamber 4B communicates with the third chamber 4C via passages 445c and 445d of the control piston 445. Therefore, the second chamber 4B and the third chamber 4C communicate with the reservoir 171 through the pipes 414 and 161. One of the first pilot chambers 4 </ b> D is closed by a pressure increasing valve 42, and the other communicates with the reservoir 171 through the pressure reducing valve 41. The first pilot chamber 4D and the second chamber 4B are kept at the same pressure. The second pilot chamber 4E communicates with the first master chamber 1D via the pipes 511 and 51 and is maintained at the same pressure.

  From this state, when the brake pedal 10 is depressed, the brake ECU 6 controls the pressure reducing valve 41 and the pressure increasing valve 42 based on the target friction braking force. That is, the brake ECU 6 controls the pressure reducing valve 41 in the closing direction and the pressure increasing valve 42 in the opening direction.

  When the pressure increasing valve 42 is opened, the accumulator 431 and the first pilot chamber 4D communicate with each other. By closing the pressure reducing valve 41, the first pilot chamber 4D and the reservoir 171 are shut off. The pressure in the first pilot chamber 4D can be increased by the high-pressure hydraulic fluid supplied from the accumulator 431. As the pressure in the first pilot chamber 4D increases, the control piston 445 slides toward the cylinder bottom surface. As a result, the tip of the protrusion 445 b of the control piston 445 contacts the ball valve 442, and the passage 445 d is closed by the ball valve 442. Then, the second chamber 4B and the reservoir 171 are blocked.

  Further, when the control piston 445 slides toward the cylinder bottom surface side, the ball valve 442 is pushed and moved toward the cylinder bottom surface side by the protruding portion 445b, and the ball valve 442 is separated from the valve seat surface 444b. Accordingly, the first chamber 4A and the second chamber 4B are communicated with each other through the through passage 444a of the valve seat portion 444. High pressure hydraulic fluid is supplied from the accumulator 431 to the first chamber 4A, and the pressure in the second chamber 4B increases due to communication. Note that the greater the separation distance of the ball valve 442 from the valve seat surface 444b, the larger the hydraulic fluid flow path and the higher the hydraulic pressure in the flow path downstream of the ball valve 442. That is, as the pressure (pilot pressure) in the first pilot chamber 4D increases, the moving distance of the control piston 445 increases, the distance from the valve seat surface 444b of the ball valve 442 increases, and the liquid in the second chamber 4B increases. Pressure (servo pressure) increases. The brake ECU 6 is arranged downstream of the pressure increasing valve 42 so that the pilot pressure in the first pilot chamber 4D increases as the movement amount of the input piston 13 (operation amount of the brake pedal 10) detected by the stroke sensor 72 increases. The pressure increasing valve 42 is controlled so that the flow path of the pressure reducing valve 41 becomes larger, and the pressure reducing valve 41 is controlled so that the flow path downstream of the pressure reducing valve 41 becomes smaller. That is, as the movement amount of the input piston 13 (the operation amount of the brake pedal 10) increases, the pilot pressure increases and the servo pressure also increases.

  As the pressure in the second chamber 4B increases, the pressure in the servo chamber 1A communicating therewith also increases. Due to the pressure increase in the servo chamber 1A, the first master piston 14 moves forward, and the pressure in the first master chamber 1D increases. And the 2nd master piston 15 also moves forward and the pressure of the 2nd master chamber 1E rises. Due to the pressure increase in the first master chamber 1D, high-pressure hydraulic fluid is supplied to the ABS 53 and the second pilot chamber 4E described later. Although the pressure in the second pilot chamber 4E rises, the pressure in the first pilot chamber 4D also rises in the same manner, so the sub piston 446 does not move. In this way, the high-pressure (master pressure) hydraulic fluid is supplied to the ABS 53, and the friction brake is operated to brake the vehicle. The force that advances the first master piston 14 in the “brake control” corresponds to a force corresponding to the servo pressure.

  When releasing the brake operation, on the contrary, the pressure reducing valve 41 is opened, the pressure increasing valve 42 is closed, and the reservoir 171 communicates with the first pilot chamber 4D. As a result, the control piston 445 moves backward and returns to the state before the brake pedal 10 is depressed.

(Sliding resistance characteristics acquisition control)
The brake ECU 6 executes control for acquiring the sliding resistance component of the hysteresis amount before the vehicle is shipped or during the vehicle stop. The hysteresis amount is a change amount of the servo pressure that still changes even after the servo pressure increase control or pressure reduction control is terminated (switched to the holding control). The amount of hysteresis is calculated as the sum of the pressure-dependent component (sliding resistance component) due to the sliding resistance of the control piston 445 and the stroke component (capacity changing component of the first pilot chamber 4D) depending on the stroke of the control piston 445. Can do. The stroke component is determined according to the stroke of the control piston 445, and the stroke can be estimated from the state of brake control (servo pressure or the like).

  The brake ECU 6 acquires the characteristic of the sliding resistance component of the hysteresis amount as the characteristic of the regulator 44 by the sliding resistance characteristic (pressure-dependent characteristic) acquisition control described below. The sliding resistance characteristic can be considered to be different for each vehicle type and vehicle. The sliding resistance characteristic acquisition control includes a hysteresis amount acquisition process and a hysteresis characteristic derivation process. The brake ECU 6 learns the sliding resistance characteristic of the hysteresis amount in the mounted vehicle. Specifically, the brake ECU 6 includes, as functions, a hysteresis amount acquisition unit 61 that performs a hysteresis amount acquisition process and a characteristic derivation unit 62 that performs a hysteresis characteristic derivation process.

  The hysteresis amount acquisition unit 61 executes a hysteresis amount acquisition process to be described later. Specifically, the hysteresis amount acquisition unit 61 controls the pressure increasing valve 42 and the pressure reducing valve 41 to change the servo pressure from a predetermined start pressure with a predetermined pressure gradient, and then the servo pressure exceeds a predetermined value. At this time, the pressure increasing valve 42 and the pressure reducing valve 41 are closed. Then, the hysteresis amount obtaining unit 61 measures and stores the change amount of the servo pressure that changes after the pressure increasing valve 42 and the pressure reducing valve 41 are closed and the first pilot chamber 4D is sealed. Since the change amount of the servo pressure after sealing the first pilot chamber 4D corresponds to the hysteresis amount, the change amount is stored as the hysteresis amount. In this way, the hysteresis amount acquisition process is performed when the servo pressure exceeds a predetermined value after the servo pressure is changed from the predetermined start pressure to the predetermined pressure gradient by the control of the pressure increasing valve 42 and the pressure reducing valve 41. 42 and the pressure reducing valve 41 are closed, and the amount of change in the servo pressure after the pressure increasing valve 42 and the pressure reducing valve 41 are closed is acquired as a hysteresis amount corresponding to the start pressure and the pressure gradient.

  In this embodiment, since the predetermined pressure gradient is set to a gentle gradient (approximately 6 MPa / s or less), the control piston 445 gradually moves and slightly pushes the ball valve 442 to slightly separate from the valve seat portion 444. When this is done, high-pressure hydraulic fluid flows into the servo chamber 1A. In this way, the hysteresis amount acquisition unit 61 controls the opening degree of the pressure increasing valve 42 and the pressure reducing valve 41 so that the servo pressure gradually increases or decreases. As a result, the stroke of the control piston 445 when the servo pressure increases is the amount by which the ball valve 442 is pushed a little, and becomes smaller. Therefore, the stroke component of the hysteresis amount can be ignored, and the acquired hysteresis amount can be treated as a sliding resistance component (pressure-dependent component). In the present embodiment, the sliding resistance characteristic with respect to the starting pressure can be obtained by deriving a hysteresis characteristic with respect to the starting pressure.

  Taking the pressure increase control as an example, as shown in FIG. 3, the hysteresis amount acquisition unit 61 closes the pressure reducing valve 41 with a constant current gradient when the servo pressure is a certain value (starting pressure). A current is supplied to the pressure increasing valve 42. When the supply current reaches the valve opening current of the pressure increasing valve 42 at t1, the pressure increasing valve 42 is opened, and the hydraulic fluid (brake fluid) flows from the accumulator 431 into the first pilot chamber 4D. The control piston 445 moves as the hydraulic fluid flows in. At t2, the control piston 445 comes into contact with the ball valve 442, and then the control piston 445 pushes the ball valve 442. The ball valve 442 is slightly separated from the valve seat 444, so that the hydraulic fluid is transferred from the accumulator 431 to the servo chamber 1A. Is supplied.

  After t2, the servo pressure gradually increases (increases with a predetermined pressure gradient), and at t3, the servo pressure (the value of the pressure sensor 74) exceeds a predetermined value. When the servo pressure exceeds a predetermined value, the hysteresis amount acquisition unit 31 determines that the servo pressure has increased (or determines that the ball valve 442 has been separated from the valve seat portion 444), and stops supplying current to the pressure increase valve 42. Then, the pressure increasing valve 42 is closed. As a result, the pressure increasing valve 42 and the pressure reducing valve 41 are closed, and the first pilot chamber 4D is sealed. Thereafter, the control piston 445 moves backward (moves to the left in FIG. 2) to return to the equilibrium state, the ball valve 442 contacts the valve seat 444, and the servo chamber 1A is shut off from the accumulator 431. The movement of the control piston 445 increases the pilot pressure and the servo pressure. The hysteresis amount obtaining unit 61 uses the pressure sensor 74 to obtain and store the amount of change in the servo pressure increased after the pressure increasing valve 42 is closed as a hysteresis amount (sliding resistance component).

  The flow of the hysteresis amount acquisition procedure will be described. As shown in FIG. 4, the hysteresis amount acquisition unit 61 first applies a control current to the pressure increasing valve 42 with a predetermined current gradient at the first start pressure (servo pressure). (S101). Thereafter, the hysteresis amount acquiring unit 61 detects that the servo pressure has exceeded a predetermined value on the basis of the value of the pressure sensor 74 based on the value of the pressure sensor 74 due to the opening of the pressure increasing valve 42 and the increase of the pilot pressure and the servo pressure (S102). . If the said detection is made, the hysteresis amount acquisition part 61 will stop the supply electric current to the pressure increase valve 42, and will close the pressure increase valve 42 (S103). Then, the hysteresis amount acquisition unit 61 acquires the amount of change in servo pressure after valve closing, that is, the amount of hysteresis (S104).

  The hysteresis amount acquisition unit 61 of the present embodiment continuously executes the above-described hysteresis amount acquisition process. That is, the hysteresis amount obtaining unit 61 obtains a plurality of hysteresis amounts by changing the servo pressure with a pressure gradient of the same level from different starting pressures. Specifically, during the pressure increase control, the hysteresis amount obtaining unit 61 closes the pressure reducing valve 41 and increases the opening of the pressure increasing valve 42 to increase the servo pressure with a predetermined pressure increase gradient, and then increase the pressure. The hysteresis amount obtaining process for obtaining the hysteresis amount corresponding to the servo pressure increase gradient by closing the pressure valve 42 is continuously executed. Further, at the time of pressure reduction control, the hysteresis amount obtaining unit 61 closes the pressure reducing valve 41 after closing the pressure increasing valve 42 and increasing the opening of the pressure reducing valve 41 to increase the servo pressure with a predetermined pressure reducing gradient. A hysteresis amount acquisition process for acquiring a hysteresis amount corresponding to the pressure reduction gradient of the servo pressure is continuously executed.

  Specifically, as illustrated in FIG. 5, the hysteresis amount acquisition unit 61 performs a hysteresis amount acquisition process using the servo pressure S <b> 1 as a start pressure in the pressure increase control. Thereby, the hysteresis amount obtaining unit 61 obtains the hysteresis amount ΔPa1 when the pressure is increased with respect to the start pressure S1. Then, after the hysteresis is generated and the servo pressure is stabilized at S2, the hysteresis amount acquisition unit 61 continues the hysteresis amount acquisition process using the servo pressure S2 as the start pressure. Thereby, the hysteresis amount obtaining unit 61 obtains the hysteresis amount ΔPa2 at the time of pressure increase with respect to the start pressure S2. Similarly, after the servo pressure becomes S3, the hysteresis amount acquisition unit 61 performs a hysteresis amount acquisition process using the servo pressure S3 as a start pressure. Thereby, the hysteresis amount obtaining unit 61 obtains the hysteresis amount ΔPa3 at the time of pressure increase with respect to the start pressure S3. In this way, the hysteresis amount acquisition unit 61 continuously acquires the hysteresis amounts for a plurality of start pressures in the pressure increase control. In this series of processes, the hysteresis amount acquiring unit 61 supplies current to the pressure increasing valve 42 with a constant current gradient.

  Subsequently, in the pressure reduction control, similarly, the hysteresis amount acquisition unit 61 performs a hysteresis amount acquisition process using the servo pressure S3 as a start pressure. Thereby, the hysteresis amount obtaining unit 61 obtains the hysteresis amount ΔPr1 at the time of depressurization with respect to the start pressure S3. Then, after the hysteresis is generated and the servo pressure is stabilized at S2, the hysteresis amount acquisition unit 61 continues the hysteresis amount acquisition process using the servo pressure S2 as the start pressure. Thereby, the hysteresis amount obtaining unit 61 obtains the hysteresis amount ΔPr2 at the time of depressurization with respect to the start pressure S2. Similarly, after the servo pressure becomes S1, the hysteresis amount acquisition unit 61 performs a hysteresis amount acquisition process using the servo pressure S1 as a start pressure. Thereby, the hysteresis amount obtaining unit 61 obtains the hysteresis amount ΔPr3 at the time of depressurization with respect to the start pressure S1. Thus, the hysteresis amount acquisition unit 61 continuously acquires the hysteresis amounts for a plurality of start pressures in the pressure reduction control. In this series of processes, the hysteresis amount obtaining unit 61 supplies current to the pressure reducing valve 42 with the same constant current gradient as that during pressure increase.

  The characteristic deriving unit 62 derives the characteristic of the hysteresis amount (sliding resistance component) with respect to the start pressure (servo pressure) based on the plurality of hysteresis amounts acquired by the hysteresis amount acquiring unit 61. For example, as shown in FIG. 6, the characteristic deriving unit 62 can derive the hysteresis characteristic (relationship between the servo pressure and the hysteresis) from the hysteresis amounts ΔPa1 to ΔPa3 with respect to the starting pressures S1 to S3 at the time of pressure increase. The hysteresis characteristic is a sliding resistance characteristic unique to the regulator 44 that has performed the processing. The relationship between the servo pressure and hysteresis (sliding resistance) is stored in the brake ECU 6 as a function expression (approximate expression: a linear function in FIG. 6) or a map. As described above, the characteristic deriving unit 62 executes the hysteresis characteristic deriving process for deriving the hysteresis characteristic (sliding resistance characteristic) from the plurality of hysteresis amounts, and stores the derived hysteresis characteristic.

  The brake ECU 6 performs brake control using the hysteresis characteristic obtained by the characteristic deriving unit 62. Even when a plurality of hysteresis amounts are not acquired, the brake ECU 6 performs brake control using the hysteresis amount acquired by the hysteresis amount acquisition unit 61. The brake ECU 6 can predict the amount of hysteresis with respect to the servo pressure, thereby enabling brake control (control of the pressure increasing valve 42 and the pressure reducing valve 41) in consideration of the amount of hysteresis.

  The brake ECU 6 can predict the hysteresis amount from the servo pressure (value of the pressure sensor 74), for example, and can widen the dead zone by the hysteresis amount. Thereby, it is possible to switch from the pressure increase control or the pressure reduction control to the holding control early with respect to the target pressure, and it is possible to suppress the occurrence of overshoot or undershoot due to hysteresis. The brake ECU 6 may control the pressure gradient of the servo pressure (pilot pressure) based on the hysteresis amount. Further, since the hysteresis amount or the hysteresis characteristic acquired by the brake ECU 6 is a sliding resistance component, the hysteresis amount depending on the stroke of the control piston 445 is separately predicted, and the accuracy of the brake control is further improved by using both hysteresis amounts. improves.

  In this embodiment, when acquiring a plurality of hysteresis amounts, control is performed so that the change in servo pressure has a gradient at the same level, and therefore, the stroke amount of the control piston 445 can be made common. That is, by setting the stroke dependent components in the plurality of acquired hysteresis amounts to the same level, it is possible to acquire a highly accurate hysteresis characteristic.

  In the present embodiment, in the hysteresis amount obtaining process, the pressure increasing valve 42 and the pressure reducing valve 41 are controlled so that the servo pressure gradually increases or decreases. That is, the hysteresis amount acquiring unit 61 supplies the supply current to the pressure increasing valve 42 (or the pressure reducing valve 41) with a small current gradient (for example, an absolute value of 6 MPa / s or less level) so that the servo pressure changes slowly and gradually. Increase (or decrease). Thereby, the stroke amount of the control piston 445 when the servo pressure changes can be reduced, and the stroke-dependent component in the hysteresis amount can be reduced to a negligible level. That is, the brake ECU 6 can acquire the sliding resistance or sliding resistance characteristics of the regulator 44.

  Further, in the hysteresis amount acquisition process, the hysteresis amount acquisition unit 61 controls one control current of the pressure increasing valve 42 and the pressure reducing valve 41 to a valve closing current value in order to change the servo pressure with a predetermined pressure gradient. The other control current of the pressure increasing valve 42 and the pressure reducing valve 41 is changed with a constant current gradient. That is, in this embodiment, in the hysteresis amount acquisition process, the control current is not supplied to the pressure increasing valve 42 or the pressure reducing valve 41 by feedback control from the value of the pressure sensor 74, but a constant current is supplied to the pressure increasing valve 42 or the pressure reducing valve 41. The pressure reducing valve 41 is supplied. Thereby, reversal of the transient pressure relationship between the first pilot chamber 4D and the servo chamber 1A can be suppressed, and the direction of the force applied to the first pilot chamber 4D can be stabilized. As a result, the accuracy of the measured hysteresis amount is improved.

  Moreover, in this embodiment, in order to acquire several hysteresis amount, the hysteresis amount acquisition process is performed continuously. Thereby, the time to acquire a plurality of hysteresis amounts due to a plurality of starting pressures can be shortened. Further, by continuously executing the hysteresis amount acquisition process, the hysteresis amount can be acquired in the same environment (a state in which there is almost no temperature change), and accurate characteristics can be acquired. In other words, since the hysteresis amount acquisition process is executed in a state where the fluid temperature (the temperature of the hydraulic fluid) is at the same level, it is possible to suppress variations in measured values due to temperature and obtain a highly accurate hysteresis characteristic.

<Second embodiment>
The vehicle brake device of the second embodiment is different from the first embodiment in the method of supplying current to the pressure increasing valve 42. Therefore, only different parts will be described. As shown in FIG. 7, the hysteresis amount acquisition unit 61 of the second embodiment first increases the control current to the pressure increasing valve 42 to an intermediate value at once. The intermediate value is set larger than the current value at the start of application and less than the valve opening current of the pressure increasing valve 42. In other words, the intermediate value is a value that is on the valve closing side with respect to the valve opening current value and that is on the valve opening side with respect to the current value in the valve closing state (at the start of application).

  The hysteresis amount obtaining unit 61 sets the current value at the time of current application to an intermediate value, and applies the control current to the pressure increasing valve 42 with a constant current gradient after applying the intermediate value to the pressure increasing valve 42 as in the first embodiment. That is, the current gradient (first gradient) from the first current value to the intermediate value is set to be larger than the current gradient (second gradient) after the intermediate value (first gradient> second gradient). As a result, the current value can be quickly increased to an intermediate value that is not related to the opening of the pressure increasing valve 42, that is, does not affect the stroke of the control piston 445. Also, as shown in FIGS. 5 and 8, the hysteresis amount acquisition process using the intermediate value can be performed continuously.

  According to the second embodiment, the same effect as the first embodiment is exhibited, and the processing time of the hysteresis amount acquisition process can be further shortened. Further, since the second gradient is a small current gradient (slope smaller than the first gradient) as in the first embodiment, the stroke of the control piston 445 is suppressed, the magnitude of the capacity change when the pressure increasing valve 42 is opened, and Variation can be suppressed.

<Third embodiment>
As shown in FIG. 9, the vehicle braking device of the third embodiment differs from the first embodiment mainly in that the brake ECU 6 includes a temperature determination unit 63. Therefore, only different parts will be described. The temperature determination unit 63 determines whether the temperature of the brake fluid (hydraulic fluid) is stable based on the value of the temperature sensor 77. The temperature sensor 77 is installed in a pipe (the pipe 422 in FIG. 9) close to the regulator 44 so that the temperature of the brake fluid in the regulator 44 can be measured. The temperature determination unit 63 determines that the temperature is stable when the value of the temperature sensor 77 is constant for a predetermined time and when the vehicle is stopped. The hysteresis amount acquisition unit 61 acquires a plurality of hysteresis amounts while the temperature determination unit determines that the temperature of the brake fluid is stable.

  According to the third embodiment, since a plurality of hysteresis amounts can be acquired while the temperature of the brake fluid is stable, that is, in a state where the brake temperature is at the same level, it is possible to acquire accurate hysteresis characteristics. . Further, according to the third embodiment, it is not always necessary to perform the hiss amount acquisition process continuously. Even if the hiss amount acquisition process is performed after a while, the process is performed while the temperature of the brake fluid is stable. Therefore, the occurrence of variation due to temperature is suppressed.

  Note that the temperature of the brake fluid may be estimated based on the outside air temperature or the operating state of the brake control, regardless of the value of the temperature sensor 77. According to this, it is not necessary to provide the temperature sensor 77 in the vehicle braking device. In addition, if the temperature changes after acquiring one or more hysteresis amounts, when the temperature of the brake fluid reaches the same level as the acquired temperature after a certain time, A quantity acquisition process may be executed. This also can suppress variations in the hysteresis amount due to temperature. Thus, according to the third embodiment, the effects of the first embodiment are exhibited, and variations in the hysteresis amount due to temperature can be suppressed more reliably. That is, accurate hysteresis characteristics can be acquired.

<Other variations>
The present invention is not limited to the above embodiment. For example, the hysteresis amount acquisition process does not have to be executed continuously, and may be executed after a certain time. Further, the hiss amount acquisition processing is not limited to before shipment of the vehicle (factory), and may be performed while the vehicle is stopped after shipment. Even after the shipment, by periodically executing the hysteresis amount acquisition process while the vehicle is stopped, it is possible to cope with the secular change of the regulator 44, the change of the temperature environment due to moving, and the like. Further, when executing the hysteresis amount obtaining process at the same level of temperature, the target temperature is not limited to the temperature of the brake fluid (hydraulic fluid) but may be the temperature of the regulator 44 itself. Further, the temperature determination unit 63 may determine that the temperature is stable when the value of the temperature sensor 77 is constant for a predetermined time regardless of whether the vehicle is stopped.

1: Master cylinder, 11: Main cylinder, 12: Cover cylinder,
13: Input piston, 14: First master piston,
15: second master piston, 1A: servo chamber, 1B: first hydraulic chamber,
1C: second hydraulic chamber, 1D: first master chamber, 1E: second master chamber,
10: Brake pedal, 171: Reservoir (low pressure source),
2: reaction force generator, 22: first control valve, 3: second control valve,
4: Servo pressure generator 41: Pressure reducing valve (pressure reducing solenoid valve)
42: pressure increasing valve (pressure increasing solenoid valve), 431: accumulator (high pressure source),
44: Regulator (pressure regulator), 445: Control piston (piston),
4D: 1st pilot room (pilot room),
541, 542, 543, 544: wheel cylinders,
5FR, 5FL, 5RR, 5RL: wheels, BF: hydraulic braking force generator,
6: Brake ECU, 61: His amount acquisition unit, 62: Characteristic deriving unit,
63: Temperature determination unit, 71: Stroke sensor, 72: Brake stop switch,
73, 74, 75, 76: Pressure sensor, 77: Temperature sensor

Claims (9)

A pressure regulator that outputs servo pressure corresponding to the pilot pressure input to the pilot chamber to the servo chamber;
A high pressure source in which a predetermined range of fluid pressure is accumulated;
A low pressure source in which a hydraulic pressure lower than the hydraulic pressure accumulated in the high pressure source is accumulated;
A pressure increasing solenoid valve for adjusting a flow rate of the liquid flowing into the pilot chamber from the high pressure source;
A pressure reducing solenoid valve that adjusts the flow rate of the liquid that flows from the pilot chamber to the low pressure source;
A vehicle braking device comprising:
When the servo pressure exceeds a predetermined value after changing the servo pressure from a predetermined start pressure with a predetermined pressure gradient by controlling the pressure increasing solenoid valve and the pressure reducing solenoid valve, the pressure increasing solenoid valve and the The amount of hysteresis is obtained by closing the pressure reducing solenoid valve and obtaining the amount of change in the servo pressure after the pressure increasing solenoid valve and the pressure reducing solenoid valve are closed as a hysteresis amount corresponding to the start pressure. A hysteresis amount acquisition unit for executing processing;
A controller for controlling the pressure increasing solenoid valve and the pressure reducing solenoid valve based on the hysteresis amount;
A vehicle braking device comprising: The hysteresis amount obtaining unit obtains a plurality of hysteresis amounts by changing the servo pressure with the pressure gradient at the same level from the different start pressures,
A characteristic deriving unit for deriving a characteristic of the hysteresis amount with respect to the start pressure based on the plurality of hysteresis amounts acquired by the hysteresis amount acquiring unit;
The vehicular braking apparatus according to claim 1, wherein the control unit controls the pressure-increasing electromagnetic valve and the pressure-reducing electromagnetic valve based on characteristics of the hysteresis amount.   The hysteresis amount acquisition unit increases the servo pressure with a predetermined pressure increase gradient by closing the pressure reducing solenoid valve and increasing the opening of the pressure increasing solenoid valve to acquire a plurality of hysteresis amounts. 3. The vehicle according to claim 2, wherein the hysteresis amount obtaining process for obtaining the hysteresis amount corresponding to the start pressure of the servo pressure by continuously closing the pressure increasing solenoid valve is performed. Braking device.   The hysteresis amount obtaining unit closes the pressure increasing solenoid valve and increases the opening of the pressure reducing solenoid valve to reduce the servo pressure with a predetermined pressure reducing gradient so as to obtain a plurality of hysteresis amounts. 4. The vehicle according to claim 2, wherein the hysteresis amount obtaining process for obtaining the hysteresis amount corresponding to the start pressure of the servo pressure by closing the pressure reducing solenoid valve is executed continuously. Braking device. The pressure regulator has a piston that is driven by a difference between a force corresponding to the pilot pressure and a force corresponding to the servo pressure, and the volume of the pilot chamber changes as the piston moves, When the flow rate of the liquid flowing into and out of the pilot chamber increases, the amount of movement of the piston relative to the position of the piston in an equilibrium state in which the force corresponding to the pilot pressure and the force corresponding to the servo pressure are balanced is increased. Configured to increase the flow rate of the liquid flowing into and out of the servo chamber,
5. The vehicle according to claim 1, wherein the hysteresis amount acquisition unit gradually increases or decreases the servo pressure when the servo pressure is changed from the predetermined start pressure with the predetermined pressure gradient. 6. Braking device.   In the hysteresis amount acquisition process, the hysteresis amount acquisition unit sets a control current of one of the pressure increasing solenoid valve and the pressure reducing solenoid valve to a valve closing current value or a current value closer to the valve closing side than the valve closing current value. And controlling the other control current of the pressure-increasing solenoid valve and the pressure-reducing solenoid valve from the current value in the closed state, closer to the valve side than the valve opening current value and from the current value in the valve closed state. The servo pressure is changed with the predetermined pressure gradient by changing the intermediate pressure from the intermediate value to the intermediate value which is the valve opening side, and changing from the intermediate value to the valve opening side with the second gradient smaller than the first gradient. The brake device for vehicles as described in any one of Claims 1-5.   In the hysteresis amount acquisition process, the hysteresis amount acquisition unit sets a control current of one of the pressure increasing solenoid valve and the pressure reducing solenoid valve to a valve closing current value or a current value closer to the valve closing side than the valve closing current value. The control pressure is changed at a predetermined current gradient to change the other control current of the pressure increasing solenoid valve and the pressure reducing solenoid valve, and the servo pressure is changed at the predetermined pressure gradient. The vehicle braking device according to one item.   The said control part controls the said solenoid valve for pressure increase and the said solenoid valve for pressure reduction based on the said some hysteresis amount acquired by the said hysteresis amount acquisition part in the state where brake temperature is the same level. The braking device for vehicles as described in any one of Claims 7. A temperature determination unit for determining whether the temperature of the brake fluid is stable,
The vehicular braking device according to claim 8, wherein the hysteresis amount acquiring unit acquires a plurality of the hysteresis amounts while the temperature determining unit determines that the temperature of the brake fluid is stable.

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