JP2015214270A - Braking device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a braking device for a vehicle capable of suppressing heating of a coil while suppressing effect on a braking force without increasing the size of the coil.SOLUTION: A braking device for a vehicle includes a normal-open type electromagnetic valve which prevents an operation liquid from flowing out of a liquid pressure chamber, generating a liquid pressure related to a braking force applied on a wheel of a vehicle, to a low pressure source. It derives an electric resistance of a coil of the electromagnetic valve, and on the basis of the derived electric resistance, controls a coil current which is made to flow the coil of the electromagnetic valve. The coil current comprises a sum of an addition current and an open valve current set according to a liquid pressure difference in a state in which the electromagnetic valve is closed. The current control part gradually reduces the addition current as a temperature of a coil d gradually rises, which is acquired by a coil temperature acquiring part, in a case where an instruction acquiring part acquires a pressure increase instruction or a holding instruction.

Description

  The present invention relates to a vehicle braking device.

  As a vehicle braking device, for example, a hydraulic fluid (brake fluid) is provided between an output piston and a master cylinder, an output piston that is driven by a force corresponding to the fluid pressure in the servo chamber, and changes the volume of the master chamber. An input piston that divides the first hydraulic pressure chamber that is filled and interlocks with the operation of the brake operation member, a regulator that outputs a hydraulic pressure corresponding to the hydraulic pressure input to the pilot chamber, and a control that is input Some include a pilot pressure generating section that generates a hydraulic pressure corresponding to the signal in the pilot chamber. Here, the pilot pressure generating unit includes, for example, an electromagnetic valve, a high pressure source, a low pressure source, and the like. Such a brake device for vehicles is described in JP, 2011-240873, A.

  The solenoid valve used for controlling the pilot pressure is a so-called solenoid valve, and the flow rate or the differential pressure between the inlet and outlet is controlled by a control current (coil current) supplied to a coil (solenoid). In other words, the solenoid valve is a linear solenoid valve capable of changing the generated differential pressure in accordance with the value of current flowing through the coil. The normally open solenoid valve is in a valve open state if the control current is equal to or less than the valve open current, and is in the valve closed state if the current is greater than the valve open current. The valve opening current is a value determined by the differential pressure at the inlet / outlet of the electromagnetic valve, but in most cases, it is set to an estimated value estimated by design in electronic control. Therefore, in order to reliably close the normally open solenoid valve, the control current supplied to the solenoid valve is a value obtained by adding a predetermined addition current to the valve opening current (estimated value). For normally open solenoid valves installed in a hydraulic chamber such as a pilot chamber, a control current larger than the set valve opening current is supplied when the valve is closed in order to maintain certainty.

  A high control current is applied to the coil of such a solenoid valve in accordance with the brake operation. For example, when the vehicle is stopped, there is a possibility that the brake operation is performed for a long time with a high pedaling force. In this case, control for applying a high hydraulic pressure to the wheel cylinder with respect to a high pedaling force is continuously performed. As a result, the normally open electromagnetic valve provided in the hydraulic pressure chamber that should maintain a high hydraulic pressure continues to prevent the hydraulic fluid from flowing out, and thus a high control current continues to be conducted. When a high current is conducted to the solenoid valve for a long time, there is a concern about heat generation of the coil of the solenoid valve.

  The brake device described in Japanese Patent Laid-Open No. 2001-30889 is configured such that, when the vehicle is stopped, a normally open solenoid valve disposed between the master cylinder and the pressure booster is connected from the master cylinder to the pressure booster. Control to reduce or stop the supply of hydraulic fluid is executed. That is, in this brake device, while the vehicle is stopped, the control current is reduced or stopped so as to reduce or stop the supply of the hydraulic fluid to the pressure increasing device, thereby suppressing the heat generation of the electromagnetic valve.

JP 2011-240873 A JP 2001-30889 A

  However, in the above brake device, the amount of hydraulic fluid supplied to the pressure booster decreases or becomes zero while the vehicle is stopped, and the influence on the control of the pressure booster increases. In addition, for a hydraulic chamber such as a pilot chamber in which hydraulic pressure related to braking force is generated, in the above control method of the brake device, the control of the normally open type electromagnetic valve directly affects the hydraulic pressure. The braking force will be affected.

  On the other hand, it is possible to cope with the occurrence of failure due to heat generation by enlarging the coil for the normally open solenoid valve installed in the hydraulic chamber as described above, but the physique (installation space) and It is not realistic in terms of cost.

  The present invention has been made in view of such circumstances, and provides a vehicle braking device that can suppress heat generation of a coil while suppressing an influence on braking force without increasing the size of the coil. The purpose is to provide.

  The vehicular braking device according to aspect 1 of the present invention normally prevents the hydraulic fluid from flowing out from the hydraulic pressure chamber in which the hydraulic pressure related to the braking force applied to the wheels of the vehicle is generated to the low pressure source by closing the valve. A vehicular braking device including an open type electromagnetic valve, for deriving an electric resistance of a coil of the electromagnetic valve, and controlling a coil current conducted to the coil of the electromagnetic valve based on the derived electric resistance. An instruction acquisition unit for acquiring a pressure increasing instruction for increasing the hydraulic pressure of the hydraulic pressure chamber or a holding instruction for holding the hydraulic pressure of the hydraulic pressure chamber, and a coil for acquiring the temperature of the coil of the normally open solenoid valve A temperature acquisition unit; and a current control unit that controls the coil current corresponding to a hydraulic pressure difference between the hydraulic chamber side of the normally open solenoid valve and the low pressure source, and the normally open solenoid valve The coil current when the valve is closed is the normally open solenoid valve The current control unit is configured by a sum of a valve opening current that is correlated with a current when the valve is opened from the closed state and is set corresponding to the hydraulic pressure difference, and an addition current. When the pressure instruction or the holding instruction is acquired, the addition current is decreased as the temperature of the coil acquired by the coil temperature acquisition unit is higher.

  According to this configuration, when the coil of the electromagnetic valve generates heat, the coil temperature is acquired by the coil temperature acquisition unit, and the coil current that is conducted to the electromagnetic valve is reduced. Thereby, the heat_generation | fever of a coil is suppressed. Furthermore, according to the above aspect 1, since only the addition current of the coil current is reduced, at least the valve opening current is maintained, and the normally closed electromagnetic valve is easily maintained in the closed state. Therefore, heat generation is suppressed, the influence on the hydraulic pressure in the hydraulic chamber is suppressed, and the influence on the braking force is also suppressed. In addition, since the heat generation is suppressed, the coil may be a normal one, and it is not necessary to take measures against failure due to an increase in the size of the coil.

  The vehicular braking apparatus according to aspect 2 of the present invention includes a valve opening determination unit that determines whether or not the normally open electromagnetic valve is open in aspect 1, and the current control unit includes: When the pressure increasing instruction or the holding instruction is acquired by the instruction acquiring unit, the coil current is determined by the valve opening determining unit according to the temperature of the coil acquired by the coil temperature acquiring unit. Decrease until it is determined that the normally open solenoid valve is open, and when the valve open determination unit determines that the normally open solenoid valve is open, the valve open determination unit Thus, the coil current is increased until it is not determined that the normally open solenoid valve is open.

  According to this configuration, the solenoid valve is closed with a coil current that is as small as possible (for example, a value slightly larger than the actual valve opening current) that can maintain a state in which the solenoid valve is not determined to be open (ie, a closed state). The valve state can be maintained. Thereby, the influence on the hydraulic pressure and the braking force is suppressed, and the heat generation of the coil is further suppressed.

  The braking device for a vehicle according to aspect 3 of the present invention is an electromagnetic valve that prevents the hydraulic fluid from flowing into the hydraulic chamber by closing the valve in aspect 1 or 2, and is opened and closed by the second coil current. A normally closed solenoid valve to be controlled, and the current control unit is acquired by the coil temperature acquisition unit when the pressure increase instruction or the holding instruction is acquired by the instruction acquisition unit Depending on the temperature of the coil, the addition current is reduced until the normally open solenoid valve is opened, and the second coil current corresponding to the decrease in the addition current is reduced to the normally closed solenoid valve. And the normally closed solenoid valve is opened.

  According to this configuration, when the addition current of the normally open solenoid valve is reduced and the coil current is equal to or less than the “actual valve open current”, that is, the normally open solenoid valve is opened and the working fluid is liquidated. When leaking from the pressure chamber, the second coil current corresponding to the decrease in the added current flows through the normally closed solenoid valve. As a result, the normally closed solenoid valve is opened, and at least the hydraulic fluid leaking from the hydraulic chamber is compensated via the normally closed solenoid valve. According to the above aspect 3, the hydraulic fluid flows into the hydraulic pressure chamber via the normally open type electromagnetic valve, and the decrease in the hydraulic pressure is suppressed, and the normally open type electromagnetic valve and the normally closed type electromagnetic valve are The heat generation is dispersed by the above, and the heat generation of the coil of the normally open solenoid valve is further suppressed.

  In the vehicle braking apparatus according to aspect 4 of the present invention, in the aspect 1, the current control unit receives the pressure-increasing instruction or the holding instruction by the instruction acquisition unit, and the temperature determination unit determines the temperature of the coil. Is equal to or higher than a predetermined temperature, the addition current is decreased by a predetermined amount.

  According to this configuration, two types of control patterns are executed when the coil is in the normal temperature range and when the coil is at a high temperature, so that the coil current is maintained at a value greater than the valve opening current. The coil current at high temperature becomes small. That is, according to the aspect 4, the influence of the hydraulic pressure and the braking force is suppressed, the heat generation of the coil is suppressed, the control is prevented from being complicated as much as possible, and the manufacturing cost is suppressed.

  The vehicular braking apparatus according to aspect 5 of the present invention normally prevents the hydraulic fluid from flowing out from the hydraulic pressure chamber in which the hydraulic pressure related to the braking force applied to the wheels of the vehicle is generated to the low pressure source by closing the valve. An open type solenoid valve is provided, the electrical resistance of the coil of the normally open type solenoid valve is derived, and the coil current that is conducted to the coil of the normally open type solenoid valve is controlled based on the derived electrical resistance. An instruction acquisition unit for acquiring a pressure increasing instruction for increasing the hydraulic pressure in the hydraulic pressure chamber or a holding instruction for holding the hydraulic pressure in the hydraulic pressure chamber, and the normally open solenoid valve A coil temperature acquisition unit for acquiring a coil temperature, a current control unit for controlling the coil current corresponding to a hydraulic pressure difference between the hydraulic pressure chamber side of the normally open solenoid valve and the low pressure source, and the liquid A normally closed solenoid valve that prevents the hydraulic fluid from flowing into the pressure chamber by closing the valve. The current control unit, when the pressure increase instruction or the holding instruction is acquired by the instruction acquisition unit, according to the temperature of the coil acquired by the coil temperature acquisition unit, The coil current is reduced until the normally open solenoid valve is opened, and the normally closed solenoid valve is opened based on the pressure increasing instruction or the holding instruction acquired by the instruction acquiring unit. It is characterized by that.

  According to this configuration, when the coil current of the normally open solenoid valve becomes equal to or less than the actual valve open current, the normally closed solenoid valve opens according to the pressure increase instruction or the hold instruction. For example, when a normally open solenoid valve is opened, a current (second coil current) corresponding to the instruction flows through the coil of the normally closed solenoid valve, and the normally closed solenoid valve is opened. According to the above aspect 5, the hydraulic fluid flows into the hydraulic pressure chamber through the normally open solenoid valve to realize the pressure increasing instruction or the holding instruction, and the normally open solenoid valve and the normally closed solenoid valve are realized. Heat generation is distributed between the valve and the heat generation of the coil of the normally open solenoid valve is further suppressed.

  The vehicular braking apparatus according to aspect 6 of the present invention normally prevents the hydraulic fluid from flowing out from the hydraulic chamber in which the hydraulic pressure related to the braking force applied to the wheels of the vehicle is generated to the low pressure source by closing the valve. A vehicular braking device including an open type electromagnetic valve, for deriving an electric resistance of a coil of the electromagnetic valve, and controlling a coil current conducted to the coil of the electromagnetic valve based on the derived electric resistance. An instruction acquisition unit for acquiring a pressure increasing instruction for increasing the hydraulic pressure of the hydraulic pressure chamber or a holding instruction for holding the hydraulic pressure of the hydraulic pressure chamber, and a coil for acquiring the temperature of the coil of the normally open solenoid valve A temperature acquisition unit; and a current control unit that controls the coil current corresponding to a hydraulic pressure difference between the hydraulic chamber side of the normally open solenoid valve and the low pressure source, and the normally open solenoid valve The coil current when the valve is closed is the normally open solenoid valve The current control unit is configured by a sum of a valve opening current that is correlated with a current when the valve is opened from the closed state and is set corresponding to the hydraulic pressure difference, and an addition current. When the pressure instruction or the holding instruction is acquired, as a control result, the temperature of the coil acquired by the normal control and the coil temperature acquisition unit is higher than the temperature in the normal control, and the addition current is Heat generation suppression control including high temperature control smaller than the addition current in normal control is performed.

  According to this configuration, the heat generation suppression control realizes a control result including at least two of normal control with a relatively low temperature and a relatively large addition current and high temperature control with a relatively high temperature and a relatively small addition current. Is done. Moreover, in the said heat_generation | fever suppression control, a coil current is maintained more than a valve opening current. Thereby, the influence of the hydraulic pressure and the braking force is suppressed, and the heat generation of the coil is suppressed. In addition, since the heat generation is suppressed, the coil may be a normal one, and a heat generation countermeasure due to an increase in the size of the coil becomes unnecessary.

It is a block diagram which shows the structure of the vehicle braking device of 1st embodiment. It is a conceptual diagram for demonstrating an example of a solenoid valve. It is sectional drawing which shows the detailed structure of the regulator of 1st embodiment. It is explanatory drawing for demonstrating the brake control (hydraulic pressure control) of the braking device for vehicles of 1st embodiment. It is a time chart for demonstrating the heat_generation | fever suppression control of 1st embodiment. It is a flowchart for demonstrating the heat_generation | fever suppression control of 1st embodiment. It is a block diagram which shows the structure of the vehicle braking device of 2nd embodiment. It is a time chart for demonstrating the heat_generation | fever suppression control of 2nd embodiment. It is a flowchart for demonstrating the heat_generation | fever suppression control of 2nd embodiment. It is a time chart for demonstrating the heat_generation | fever suppression control of 3rd embodiment. It is explanatory drawing for demonstrating the deformation | transformation aspect of this embodiment. It is explanatory drawing for demonstrating the deformation | transformation aspect of this embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings. Each figure used for explanation is a conceptual diagram, and the shape of each part may not necessarily be exact.

<First embodiment>
As shown in FIG. 1, the vehicle braking device of the first embodiment controls a hydraulic braking force generator BF that generates hydraulic braking force on the wheels 5FR, 5FL, 5RR, and 5RL, and a hydraulic braking force generator BF. And a brake ECU 6.

(Hydraulic braking force generator BF)
As shown in FIG. 1, the hydraulic braking force generator BF includes a master cylinder 1, a reaction force generator 2, a first control valve 22, a second control valve 23, a servo pressure generator 4, and a hydraulic pressure. It is comprised by the control part 5, various sensors 71-76 grade | etc.,.

(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.

  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. 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 1A” is on the rear side. It 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 (corresponding to a “low pressure source”).

  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) 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 “normally open electromagnetic valve”) 41, a pressure increasing valve (corresponding to a “normally closed electromagnetic valve”) 42, a pressure supply unit 43, a regulator 44, and the like. It consists of The pressure reducing valve 41 is a normally open solenoid valve (normally open valve) that opens in a non-energized state, and the flow rate (or pressure) 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 of the pressure reducing valves 41 communicates with the reservoir 171 through the pipes 411 and 161 and the ports 11a and 11b. The pressure reducing valve 41 is closed to prevent the hydraulic fluid from flowing out from the first pilot chamber 4D described later. 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 a normally closed electromagnetic valve (normally closed valve) that is closed in a non-energized state, and the flow rate (or pressure) 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 is an electromagnetic valve that prevents the hydraulic fluid from flowing into a first pilot chamber 4D, which will be described later, by closing the valve. The pressure increasing valve 42 is an electromagnetic valve that prevents the hydraulic fluid from flowing into a first pilot chamber 4D described later by closing the valve.

  Here, an example of a normally open type electromagnetic valve used for the pressure reducing valve 41 will be schematically described. As shown in FIG. 2, the solenoid valve (pressure reducing valve 41) includes a valve member a, a valve seat b, a spring c that urges the valve member a toward the valve opening side (a direction away from the valve seat b), and an electric current. And a coil (solenoid) d that generates an electromagnetic driving force that pushes the valve member a toward the valve closing side. When the current flowing through the coil d is equal to or less than the actual valve opening current, the valve member a and the valve seat b are separated by the urging force of the spring c, and the electromagnetic valve is in the valve open state. When a current larger than the actual valve opening current flows through the coil d, the electromagnetic driving force that pushes the valve member a generated in the coil d toward the valve closing side becomes the differential pressure between the biasing force of the spring c and the inlet / outlet of the electromagnetic valve. As a result, the valve member a comes into contact with the valve seat b, and the solenoid valve is closed.

  The valve opening current is determined by the differential pressure between the inlet and outlet of the solenoid valve. In a normally open type solenoid valve, the “actual valve opening current” that is not the set value (estimated value) is the maximum control current that will cause the valve to open, and is the minimum control current (minimum closing). This also corresponds to the valve current. That is, the actual valve opening current can be said to be a control current for switching between opening and closing. In this specification, the “valve opening current” is a value that correlates to a control current when the electromagnetic valve is opened from the closed state and is set according to the differential pressure. Further, in this specification, “actual valve opening current” is not a set value (estimated value) but a current value at which the opening / closing of the solenoid valve is actually switched. Therefore, the “valve opening current” may not match the “actual valve opening current”.

  As described above, the pressure reducing valve 41 and the pressure increasing valve 42 have a differential pressure acting force according to an electromagnetic driving force generated by passing a current through the coil d, an urging force of the spring c, and a differential pressure between the inlet and outlet of the electromagnetic valve. Opening and closing is determined by the balance relationship between and is controlled by a current (control current) supplied to the coil d. The direction of the urging force and the electromagnetic driving force varies depending on the structure of the electromagnetic valve (such as a normally open valve or a normally closed valve).

  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 (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. 3, the regulator (mechanical pressure adjusting device) 44 includes a cylinder 441, a ball valve 442, an urging portion 443, a valve seat portion 444, a control piston 445, 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 “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 “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“ hydraulic chamber ”. 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 (not shown) on a wall portion facing the first pilot chamber 4D. The damper device is configured as 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, 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 in each wheel. 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. Brake control is control of normal hydraulic braking force. 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 driver's required braking force from the operation amount of the brake pedal 10 (the amount of movement of the input piston 13) detected by the stroke sensor 71 or the operation force of the brake pedal 10. Then, the target servo pressure is set based on the required braking force, and the pressure reducing valve 41 and the actual servo pressure (corresponding to “actual pressure”) that is the servo pressure measured by the pressure sensor 74 are brought close to the target servo pressure. The pressure increasing valve 42 is controlled.

  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.

  When the brake pedal 10 is depressed from this state, the brake ECU 6 controls the pressure reducing valve 41 and the pressure increasing valve 42 based on the target servo pressure. 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 causes the flow 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 (the operation amount of the brake pedal 10) detected by the stroke sensor 71 increases. The pressure increasing valve 42 is controlled so that the path 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. The servo pressure can be acquired by the pressure sensor 74 and can be converted into a pilot pressure.

  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.

  In the brake control of the first embodiment, the target servo pressure is set according to the operation and stroke of the brake pedal 10, and the pressure reducing valve 41 and the pressure increasing valve 42 are controlled so that the servo pressure reaches the target servo pressure. It is the control which changes. The target servo pressure is set based on a map or the like. In the first embodiment, as described above, the pressure reducing valve 41 and the pressure increasing valve 42 are electromagnetic valves whose actual valve opening current (or minimum valve opening current) varies depending on the differential pressure between the inlet and outlet.

  In the brake ECU 6, as shown in FIG. 4, a predetermined dead zone is set for the target servo pressure. When performing the hydraulic pressure control, the brake ECU 6 recognizes that the actual servo pressure has substantially reached the target servo pressure when it falls within the dead zone. By setting such a dead zone, it is possible to suppress hunting of hydraulic pressure control as compared with the case where the target servo pressure is set to one point.

  In the brake control, when the deviation between the target servo pressure and the actual servo pressure is outside the dead zone, the brake ECU 6 controls the actual servo pressure so that the deviation falls within the dead zone. When the deviation from the servo pressure is within the dead zone, the actual servo pressure is controlled so as to maintain the actual servo pressure. The brake ECU 6 performs feedback control for controlling the pressure reducing valve 41 and the pressure increasing valve 42 while monitoring the value of the pressure sensor 74.

  When the actual servo pressure is outside the dead zone range and smaller than the target servo pressure, the brake ECU 6 enters a “pressure increase mode (pressure increase instruction)” that increases the actual servo pressure toward the target servo pressure. In addition, when the actual servo pressure is outside the dead zone and greater than the target servo pressure, the brake ECU 6 enters a “decompression mode (decompression instruction)” for decreasing the actual servo pressure toward the target servo pressure. The brake ECU 6 enters a “holding mode (holding instruction)” for holding the actual servo pressure when the actual servo pressure is within the dead zone. For example, the brake ECU 6 opens the pressure increasing valve 42 and closes the pressure reducing valve 41 in the pressure increasing mode, and closes the pressure increasing valve 42 and opens the pressure reducing valve 41 in the pressure reducing mode. In the mode, the pressure increasing valve 42 and the pressure reducing valve 41 are closed.

(Heat generation suppression control)
The brake ECU 6 includes a current control unit 61, a current detection unit 62, a voltage application unit 63, an instruction acquisition unit 64, and a coil temperature acquisition unit 65 as functions. The current control unit 61 executes the “brake control” by controlling a control current (corresponding to “coil current”) applied to the pressure reducing valve 41 and the pressure increasing valve 42. Since the control current is a current flowing through the coil d of the electromagnetic valve, it can be said to be a coil current. The current control unit 61 sets a target control current (target control current) for the pressure reducing valve 41 and the pressure increasing valve 42 based on the target servo pressure and the control mode. In addition, the current control unit 61 performs heat generation suppression control under a predetermined condition. This will be described later.

  When it is desired to close the pressure reducing valve 41, the target control current is set to a value larger than the valve opening current set corresponding to the differential pressure at the inlet / outlet of the pressure reducing valve 41 in accordance with the required braking force. In other words, when it is desired to close the pressure reducing valve 41, the target control current is set as the sum of the valve opening current and an addition current (for example, a current corresponding to a differential pressure of several MPa). On the other hand, when it is desired to open the pressure reducing valve 41, the target control current is set to be equal to or less than the valve opening current according to the required braking force. The current control unit 61 stores a relationship (map) between the differential pressure in the pressure reducing valve 41 and the valve opening current. The valve opening current stored in the current control unit 61 is an estimated value estimated by design.

  When it is desired to close the pressure increasing valve 42, the target control current is set to be less than the minimum valve opening current set corresponding to the differential pressure at the inlet / outlet of the pressure increasing valve 42 according to the required braking force. When it is desired to open the pressure increasing valve 42, the target control current is set to a value larger than the minimum valve opening current according to the required braking force. The current control unit 61 also stores a relationship (map) between the differential pressure in the pressure increasing valve 42 and the minimum valve opening current.

  The current detection unit 62 is, for example, a current sensor, and detects a current flowing through the coil d of the pressure reducing valve 41. Based on the target current value set by the current control unit 61 and the current (detected current) detected by the current detection unit 62, the voltage application unit 63 sets the coil of the pressure reducing valve 41 so that the control current becomes the target current value. A voltage is applied to d. The control current is determined by the applied voltage and the resistance of the coil d, and the resistance of the coil d changes with temperature. The voltage application unit 63 is supplied with power from a battery (not shown) and controls the applied voltage by PWM.

  The instruction acquisition unit 64 acquires a pressure increasing instruction for increasing the pilot pressure or a holding instruction for holding the pilot pressure. In other words, the instruction acquisition unit 64 acquires information indicating what mode (the pressure increasing mode, the holding mode, or the pressure reducing mode) the current control mode is. The instruction acquisition unit 64 can be said to be a part of the function of the current control unit 61.

  The coil temperature acquisition unit 65 acquires the temperature of the coil d of the pressure reducing valve 41. Specifically, the coil temperature acquisition unit 65 first derives the resistance of the coil d of the pressure reducing valve 41 based on the current detected by the current detection unit 62 and the voltage applied by the voltage application unit 63. When the detection current of the current detection unit 62 is stable, the coil temperature acquisition unit 65 calculates a resistance from the detection current and the applied voltage. Resistance can be derived (calculated) by Ohm's law (V = IR). The coil temperature acquisition unit 65 periodically derives the resistance of the coil d. “Whether the current has stabilized” is, for example, whether the detection current for a predetermined time is at a constant level, whether the target control current is maintained for a predetermined time, whether the applied voltage for a predetermined time is at a constant level, etc. Can be determined.

  The coil temperature acquisition unit 65 estimates the temperature of the coil d based on the resistance of the coil d and the detected current (or applied voltage). The temperature of the coil d can be estimated by comparing the calculated resistance of the coil d with a resistance value when the ECU is activated or a resistance value stored in advance. Thus, the coil temperature acquisition unit 65 of the first embodiment periodically acquires the temperature of the coil d from the resistance of the coil d. The temperature of the coil d can be estimated by a known method based on the resistance of the coil d.

  Here, the current control unit 61 performs the heat generation suppression control when the pressure increasing instruction or the holding instruction is acquired by the instruction acquiring unit 64. The heat generation suppression control is control in which the added current in the control current (target control current) is reduced as the temperature of the coil d acquired by the coil temperature acquisition unit 65 is higher. In other words, the current control unit 61 reduces the control current while maintaining the valve opening current or more according to the coil temperature. More specific description will be given below.

  As shown in FIG. 5, in the heat generation suppression control, the current control unit 61 reduces the addition current by a predetermined amount when the temperature acquired by the coil temperature acquisition unit 65 is equal to or higher than a predetermined temperature. In other words, when the acquired temperature is equal to or higher than the predetermined temperature (t1), the current control unit 61 changes the addition current in the target control current from the normal addition current value (for example, the addition current corresponding to the differential pressure of 5 MPa) to the high temperature addition current value. (For example, an additional current corresponding to a differential pressure of 2 MPa). The high temperature addition current value is smaller than the normal addition current value by a predetermined amount. As a result, the control current is changed from a normal control current (valve opening current value + normal addition current value) to a control current at high temperature (valve opening current value + high temperature addition current value) smaller than that.

  A flow of heat generation suppression control by the brake ECU 6 will be described. As shown in FIG. 6, when the brake ECU 6 is in the pressure increasing mode or the holding mode (S101: Yes), the brake ECU 6 determines whether or not the temperature acquired by the coil temperature acquisition unit 65 is equal to or higher than a predetermined temperature (S102). . When the acquisition temperature is equal to or higher than the predetermined temperature (S102: Yes), the addition current in the target control current is changed from the normal addition current to the high temperature addition current to be small (S103).

  According to the first embodiment, when the temperature of the coil d becomes equal to or higher than the predetermined temperature in the pressure increasing mode or the holding mode, the current that flows through the coil d becomes smaller than normal because the added current becomes smaller. Thereby, the heat generation pace of the coil d can be lowered. Furthermore, according to the first embodiment, the valve opening current is maintained in order to reduce the addition current of the control current. Thereby, even if it is during heat_generation | fever suppression control, the closed state of the pressure-reduction valve 41 is easy to be maintained, and the influence on pilot pressure is suppressed. In particular, in the normally open type electromagnetic valve (pressure reducing valve 41) for controlling the pilot pressure directly related to the magnitude of the braking force as in the first embodiment, the flow rate of the hydraulic fluid directly affects the braking force. The effect of maintaining the closed state is great. Moreover, since heat generation is suppressed by the above control, it is not necessary to increase the size of the coil.

  The current control unit 61 may reduce the addition current linearly with respect to the acquisition temperature of the coil temperature acquisition unit 65 as shown in FIG. 11 when reducing the addition current to the pressure reducing valve 41. Further, when reducing the addition current to the pressure reducing valve 41, the current control unit 61 may reduce the addition current in multiple stages with respect to the acquisition temperature of the coil temperature acquisition unit 65, as shown in FIG. .

<Second embodiment>
The vehicular braking apparatus of the second embodiment is mainly different from the first embodiment in that, when the temperature further rises after the addition current is reduced in the heat generation suppression control, the entire control current is gradually reduced. Is different. Therefore, a different part is demonstrated.

  As shown in FIG. 7, the brake ECU 6 of the second embodiment further includes a valve opening determination unit 66 in addition to the first embodiment. The valve opening determination unit 66 determines whether or not the pressure reducing valve 41 is open in the heat generation suppression control. Specifically, the valve opening determination unit 66 monitors the actual servo pressure by the pressure sensor 74, and determines whether or not the actual servo pressure has become smaller than a predetermined pressure in the holding mode. When the actual servo pressure is stable in the holding mode, the valve opening determination unit 66 does not determine that the pressure reducing valve 41 is open (that is, determines that the valve is closed). Further, the valve opening determination unit 66, when the control current (or target control current) detected by the current detection unit 62 is equal to or greater than a value obtained by adding a predetermined current (for example, high temperature addition current) to the valve opening current, It is not determined that the pressure reducing valve 41 is open. In the pressure increasing mode, the valve opening determination unit 66 determines whether or not the pressure reducing valve 41 is open based on the change in the change rate of the actual servo pressure with respect to the change rate (inclination) of the target servo pressure. To do.

  As shown in FIG. 8, when the temperature still rises after the addition current is reduced by a predetermined amount at t1, and the temperature acquired by the coil temperature acquisition unit 65 is equal to or higher than the second predetermined temperature (t2), The controller 61 gradually decreases the target control current. When the current control unit 61 slowly reduces the target control current (for example, a slope of 1/3 or less when the brake is depressed), when the target control current falls below the valve opening current, the pressure reducing valve 41 opens and the actual servo pressure Begins to fall. The valve opening determination unit 66 determines that the pressure reducing valve 41 is open when the actual servo pressure drops by a predetermined pressure (t3). The second predetermined temperature is a temperature higher than the predetermined temperature, and is stored in the brake ECU 6 together with the predetermined temperature.

  When it is determined that the pressure reducing valve 41 is opened (t3), the current control unit 61 once returns the target control current to the control current at the time of high temperature (valve opening current + high temperature addition current). Thereafter, when the valve opening determination unit 66 does not determine that the pressure reducing valve 41 is open, the current control unit 61 outputs the target control current and the valve opening determination unit 66 opens the pressure reducing valve 41. The target control current is set to a predetermined time before it is determined that the current is present.

  The actual servo pressure detected by the pressure sensor 74 decreases by a predetermined pressure after a short time has elapsed after the pressure reducing valve 41 is opened. Therefore, it can be estimated that the control current just before the valve opening is determined is the actual valve opening current (that is, the minimum valve closing current). The current control unit 61 assumes that the target control current a predetermined time before the valve opening is determined is the minimum value (a value obtained by adding a little current to the actual valve opening current) that can actually maintain the valve closing state. Thus, the target control current in the current holding mode is set. The target control current a predetermined time before the valve opening determination is referred to as “assumed valve closing current”. Note that the current control unit 61 may set the target control current to the assumed valve closing current at t3 without increasing the target control current to the high-temperature control current. Thus, after the valve opening determination, the current control unit 61 increases the control current (target control current) until the valve opening determination disappears.

  The flow of heat generation suppression control of the second embodiment will be described. As shown in FIG. 9, when the brake ECU 6 is in the pressure increasing mode or the holding mode (S201: Yes), the brake ECU 6 determines whether the temperature acquired by the coil temperature acquisition unit 65 is equal to or higher than a predetermined temperature (S202). . When the acquisition temperature is equal to or higher than the predetermined temperature (S202: Yes), the addition current in the target control current is changed from the normal addition current to the high temperature addition current to be small (S203).

  Subsequently, when the control mode is the pressure increasing mode or the holding mode (S204: Yes), the current control unit 61 determines whether or not the acquisition temperature of the coil temperature acquisition unit 65 is equal to or higher than the second predetermined temperature ( S205). When the acquired temperature is equal to or higher than the second predetermined temperature (S205: Yes), the current control unit 61 gradually decreases the target control current until the valve opening determination unit 66 detects the opening of the pressure reducing valve 41. (S206). When the valve opening determination unit 66 detects the opening of the pressure reducing valve (S207: Yes), the current control unit 61 is a value sufficient for the pressure reducing valve 41 to close the target control current (for example, a control current at a high temperature). And the pressure reducing valve 41 is closed (S208). That is, the current control unit 61 applies a control current that can be closed. Thereafter, the current control unit 61 sets the target control current to the assumed valve opening current on the assumption that the holding mode is maintained (S209).

  According to the second embodiment, when the temperature of the coil d rises even after the addition current is lowered by a predetermined amount, the control current can be further reduced to suppress heat generation. Further, according to the second embodiment, when the control current is reduced and the pressure reducing valve 41 is opened, it is detected and the pressure reducing valve 41 is closed again, so that the influence on the pilot pressure is suppressed, The influence on pilot pressure and braking force is also suppressed. Further, according to the second embodiment, the target control current (assumed valve closing current) a predetermined time before the valve opening determination is set to the target control current as the minimum current value that can actually maintain the valve closing. While maintaining the valve, the control current can be made as small as possible to effectively suppress the heat generation of the coil d.

  When the control current is gradually reduced, the current control unit 61 reduces the control current linearly or in multiple stages with respect to the acquisition temperature of the coil temperature acquisition unit 65 as shown in FIG. 11 or FIG. Also good.

<Third embodiment>
The vehicle braking device of the third embodiment is mainly different from the second embodiment in control after t3 in FIG. Therefore, a different part is demonstrated.

  The current control unit 61 of the third embodiment gradually decreases the control current as after t2 of FIG. 8, and for example, when a predetermined condition that makes it difficult to maintain the stop state is satisfied, the pressure increasing valve 42 Is set to a value equal to or greater than the minimum valve opening current of the pressure increasing valve 42 (the minimum value at which the pressure increasing valve 42 opens). That is, as shown in FIG. 10, the current control unit 61 gradually decreases the control current for the pressure reducing valve 41 when the acquired temperature is equal to or higher than the second predetermined temperature (t2 to t4), and the pressure increasing valve when the predetermined condition is satisfied. 42 is opened (t4).

  The predetermined condition is that the wheel speed sensor 76 detects the vehicle speed or that the actual servo pressure falls outside the range of the dead zone. The current control unit 61 determines whether or not a predetermined condition is satisfied. In normal brake control, when the actual servo pressure is located outside (below) the dead zone, the control mode is changed from the holding mode to the pressure increasing mode, the pressure increasing valve 42 is opened, and the pressure reducing valve 41 is closed. However, the current control unit 61 of the third embodiment does not close the pressure reducing valve 41 even when the mode is changed during the heat generation suppression control in which the control current is gradually reduced.

  The current control unit 61 opens the pressure increasing valve 42, stops the decrease in the control current for the pressure reducing valve 41, and increases the pilot pressure so that the pilot pressure is necessary for stopping the vehicle. That is, the current control unit 61 opens both the pressure reducing valve 41 and the pressure increasing valve 42. Thereby, the vehicle braking device of the third embodiment can disperse the heat generated by the coil d to the pressure reducing valve 41 and the pressure increasing valve 42 while maintaining the hydraulic pressure (pilot pressure) necessary for maintaining the vehicle stopped. The heat generation of the coil d of the pressure reducing valve 41 can be further suppressed.

  The current control unit 61 opens the pressure increasing valve 42 according to the control mode. The current control unit 61 opens the pressure increasing valve 42 so that the control mode (pressure increasing mode or holding mode) is maintained even when the pressure reducing valve 41 is opened in the pressure increasing mode or the holding mode. In other words, when the pressure reducing valve 41 is opened, the current control unit 61 causes the control current to flow through the pressure increasing valve 42 according to the control mode. The effect of this configuration is exhibited regardless of whether or not the addition current is set.

  Further, when the set valve opening current is set to be equal to or less than the actual valve opening current, the pressure reducing valve 41 is opened due to a decrease in the added current. Therefore, the current control unit 61 reduces only the addition current until the pressure reducing valve 41 opens, and increases the control current (corresponding to “second coil current”) corresponding to the decrease in the addition current 42. The pressure increasing valve 42 may be opened so as to compensate for at least the hydraulic fluid that has flowed out by opening the pressure reducing valve 41. At this time, in the pressure increasing mode, the pressure increasing valve 42 is opened so as to be filled with the hydraulic fluid larger than the outflow amount. The pressure valve 42 is opened.

  Note that the current control unit 61 does not depend on a predetermined condition, for example, starts control for gradually reducing the control current to the pressure reducing valve 41, gradually increases the control current to the pressure increasing valve 42, or exceeds the minimum valve opening current. It may be set to be. Moreover, you may add the determination of the valve opening determination part 66 to predetermined conditions. Further, when the current control unit 61 gradually decreases the control current to the pressure reducing valve 41, the current control unit 61 linearly or multistagely performs the acquisition temperature of the coil temperature acquisition unit 65 as shown in FIG. 11 or FIG. The control current may be reduced.

  As described above, the current control unit 61 according to the third embodiment corresponds to the temperature of the coil d acquired by the coil temperature acquisition unit 65 when the pressure increase instruction or the holding instruction is acquired by the instruction acquisition unit 64. A control current smaller than the valve opening current of the pressure reducing valve 41 is made to conduct to the pressure reducing valve 41, and when making the conduction, the pressure increasing valve 42 is made to conduct a control current larger than the minimum valve opening current.

<Other variations>
The present invention is not limited to the above embodiment. For example, the coil temperature acquisition unit 65 may estimate the temperature from the atmosphere of the engine room, for example, instead of estimating the temperature from the resistance of the coil d. For example, the coil temperature acquisition unit 65 may estimate the temperature of the coil d based on the integration (integrated value) of the control current that has flowed through the coil d after the ignition is turned on. Further, the coil temperature acquisition unit 65 may estimate the temperature of the coil d based on the ambient temperature and the integrated value. Moreover, in addition to each said estimation method, the coil temperature acquisition part 65 may calculate the thermal radiation amount of the coil d, and may estimate the temperature of the coil d based also on the said thermal radiation amount. In addition, what acquires the temperature of the coil d directly may be utilized for temperature acquisition.

  In the present invention, “to decrease the current as the temperature is higher”, at least, change the current in one step according to the temperature change (see FIG. 5), and linearly change the current corresponding to the temperature change. It includes changing (see FIG. 11) and changing the current in multiple steps in response to temperature changes (see FIG. 12).

  In addition, the heat generation suppression control of the present invention, in other words, when the pressure acquisition instruction or the holding instruction is acquired by the instruction acquisition unit 64, as a control result, as shown in FIG. It can be said that the control includes the high temperature control B in which the temperature of the coil d acquired by the acquisition unit 65 is higher than the temperature in the normal control and the added current is smaller than the added current in the normal control. Even if it is this structure, the effect similar to the said embodiment is exhibited.

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 (normally open solenoid valve),
42: Booster valve (normally closed solenoid valve), 431: Accumulator,
44: Regulator, 445: Control piston, 4D: First pilot chamber (hydraulic pressure chamber),
541, 542, 543, 544: wheel cylinders,
5FR, 5FL, 5RR, 5RL: wheels, BF: hydraulic braking force generator,
6: brake ECU (control unit), 61: current control unit, 62: current detection unit,
63: Voltage application unit, 64: Instruction acquisition unit, 65: Coil temperature acquisition unit,
66: valve opening determination unit, 71: stroke sensor,
73, 74, 75: Pressure sensor, 76: Wheel speed sensor, d: Coil

Claims (6)

A normally-open electromagnetic valve that prevents the hydraulic fluid from flowing out from a hydraulic chamber that generates hydraulic pressure related to braking force applied to a vehicle wheel to a low-pressure source by closing the valve; A vehicular braking device that derives an electrical resistance of a coil of a solenoid valve and controls a coil current to be conducted to the coil of the normally open solenoid valve based on the derived electrical resistance,
An instruction acquisition unit for acquiring a pressure increasing instruction for increasing the hydraulic pressure of the hydraulic pressure chamber or a holding instruction for holding the hydraulic pressure of the hydraulic pressure chamber;
A coil temperature acquisition unit for acquiring the temperature of the coil of the normally open solenoid valve;
A current control unit for controlling the coil current corresponding to a hydraulic pressure difference between the hydraulic chamber side of the normally open solenoid valve and the low pressure source;
With
The coil current when the normally open solenoid valve is in a closed state correlates with the current when the normally open solenoid valve opens from the closed state, and is set corresponding to the hydraulic pressure difference. The sum of the valve opening current and the additional current
The current control unit decreases the addition current as the coil temperature acquired by the coil temperature acquisition unit increases when the pressure increase instruction or the holding instruction is acquired by the instruction acquisition unit. A braking device for a vehicle. A valve opening determination unit for determining whether or not the normally open solenoid valve is open;
The current control unit, when the pressure increase instruction or the holding instruction is acquired by the instruction acquisition unit, the coil current according to the coil temperature acquired by the coil temperature acquisition unit, Decrease until it is determined that the normally open solenoid valve is opened by the valve opening determination unit, and it is determined that the normally open solenoid valve is opened by the valve opening determination unit 2. The vehicular braking apparatus according to claim 1, wherein the coil current is increased until it is determined by the valve opening determination unit that the normally open solenoid valve is not opened. A solenoid valve that prevents the hydraulic fluid from flowing into the hydraulic chamber by closing the valve, and includes a normally closed solenoid valve that is controlled to open and close by a second coil current;
The current control unit, when the pressure increasing instruction or the holding instruction is acquired by the instruction acquiring unit, according to the temperature of the coil acquired by the coil temperature acquiring unit, The addition current is reduced until the solenoid valve is opened, and the normally closed solenoid valve is turned on by causing the second coil current corresponding to the decrease in the addition current to be conducted to the normally closed solenoid valve. The vehicle braking device according to claim 1 or 2, wherein the valve is opened.   The current control unit reduces the addition current by a predetermined amount when the pressure increase instruction or the holding instruction is acquired by the instruction acquisition unit and the temperature of the coil is equal to or higher than a predetermined temperature by the temperature determination unit. The vehicle braking device according to 1. A normally-open electromagnetic valve that prevents the hydraulic fluid from flowing out from a hydraulic chamber that generates hydraulic pressure related to braking force applied to a vehicle wheel to a low-pressure source by closing the valve; A vehicular braking device that derives an electrical resistance of a coil of a solenoid valve and controls a coil current to be conducted to the coil of the normally open solenoid valve based on the derived electrical resistance,
An instruction acquisition unit for acquiring a pressure increasing instruction for increasing the hydraulic pressure of the hydraulic pressure chamber or a holding instruction for holding the hydraulic pressure of the hydraulic pressure chamber;
A coil temperature acquisition unit for acquiring the temperature of the coil of the normally open solenoid valve;
A current control unit for controlling the coil current corresponding to a hydraulic pressure difference between the hydraulic chamber side of the normally open solenoid valve and the low pressure source;
A normally closed solenoid valve that prevents the hydraulic fluid from flowing into the hydraulic chamber by closing the valve;
With
The current control unit, when the pressure increasing instruction or the holding instruction is acquired by the instruction acquiring unit, according to the temperature of the coil acquired by the coil temperature acquiring unit, The coil current is reduced until the solenoid valve is opened, and the normally closed solenoid valve is opened based on the pressure increasing instruction or the holding instruction acquired by the instruction acquiring unit. Vehicle braking device. A normally open type electromagnetic valve that prevents the hydraulic fluid from flowing out from a hydraulic pressure chamber that generates a hydraulic pressure related to a braking force applied to a vehicle wheel to a low pressure source by closing the valve; A braking device for a vehicle that controls a coil current that is conducted to a coil of the solenoid valve based on the derived electrical resistance,
An instruction acquisition unit for acquiring a pressure increasing instruction for increasing the hydraulic pressure of the hydraulic pressure chamber or a holding instruction for holding the hydraulic pressure of the hydraulic pressure chamber;
A coil temperature acquisition unit for acquiring the temperature of the coil of the normally open solenoid valve;
A current control unit for controlling the coil current corresponding to a hydraulic pressure difference between the hydraulic chamber side of the normally open solenoid valve and the low pressure source;
With
The coil current when the normally open solenoid valve is in a closed state correlates with the current when the normally open solenoid valve opens from the closed state, and is set corresponding to the hydraulic pressure difference. The sum of the valve opening current and the additional current
When the pressure increase instruction or the holding instruction is acquired by the instruction acquisition unit, the current control unit is configured to obtain, as a control result, normal control and the coil temperature acquired by the coil temperature acquisition unit as the control result. A vehicular braking apparatus that performs heat generation suppression control including high-temperature control that is higher than a temperature in normal control and in which the added current is smaller than the added current in the normal control.

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