JP2005162134A - Vehicular brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance assembly efficiency and to improve operation efficiency of a pressure increase valve and a pressure reduction valve in a vehicular brake device capable of boosting a wheel brake. <P>SOLUTION: A control piston 90 is coaxially interconnected to a rear end of a reaction force piston 92 having a front end facing a booster hydraulic control chamber 130; the pressure reduction valve 117 is constituted by a pressure reduction valve seat 146 provided on the reaction force piston 92, and a poppet type pressure reduction valve element 147 spring-energized to a rear part while the rearmost position is regulated; the pressure increase valve 116 is constituted by a pressure increase valve seat 161 forming a pressure increase valve hole 163 through which a front end of the pressure reduction valve element 147 can be inserted and provided on a valve housing 118, and a poppet type pressure increase valve element 162 capable of being pushed to the front part by the front end of the pressure reduction valve element 147 and spring-energized to the rear part; and a seal area of the pressure increase valve element 162 at seated in the pressure valve seat 161 is almost equal to a front end pressure receiving area of the pressure increase valve element 162 receiving the hydraulic pressure of a booster hydraulic chamber 25. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention includes a master cylinder in which a master piston facing the back of a boost hydraulic chamber is slidably accommodated in a casing, a control piston in which a brake operation input from a brake operation member acts in a forward direction, A reaction force piston connected coaxially to the control piston so that a reaction force based on the hydraulic pressure in the boosted hydraulic pressure chamber acts in the backward direction on the control piston, and opens when the control piston moves forward and A booster hydraulic pressure control chamber connected to the booster hydraulic pressure chamber so as to be closed when the control piston is retracted, and a pressure increasing valve interposed between the hydraulic pressure generation sources, and closed when the control piston moves forward In addition, the present invention relates to a vehicle brake device including a pressure reducing valve interposed between the boost hydraulic pressure control chamber and a reservoir so as to open when the control piston moves backward.

Such a vehicle brake device is already known from, for example, Patent Document 1 and the like.
JP 2001-146160 A

  In the conventional vehicle brake device, the control piston is slidably fitted to the casing, and the valve piston pushed from the rear by the control piston and the reaction force piston integrally connected to the valve piston are provided. A pressure reducing valve is built in the valve piston so as to be slidable, and a valve housing of the pressure increasing valve is fixed in the casing in front of the reaction force piston.

  In the brake device for a vehicle having such a configuration, it is necessary to sequentially assemble a valve piston and a control piston incorporating a pressure increasing valve, a pressure reducing valve, and it is difficult to say that it is excellent in assembling. .

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vehicular brake device in which the ease of assembly is improved and the operability of the pressure increasing valve and the pressure reducing valve is improved.

  In order to achieve the above-mentioned object, the invention according to claim 1 is directed to a master cylinder in which a master piston having a back face facing a boost hydraulic chamber is slidably accommodated in a casing, and a brake operation from a brake operation member. A control piston having an input acting in a forward direction; and a reaction force piston coaxially connected to the control piston so as to cause a reaction force based on the hydraulic pressure in the boost hydraulic chamber to act in a backward direction on the control piston; The control piston is interposed between the boost hydraulic pressure control chamber connected to the boost hydraulic pressure chamber and the hydraulic pressure generating source so as to open when the control piston moves forward and close when the control piston moves backward. A vehicle having a pressure increasing valve and a pressure reducing valve interposed between the boost hydraulic pressure control chamber and the reservoir so as to close when the control piston moves forward and open when the control piston moves backward In the rake device, the backup piston, whose front end is restricted while facing the front surface of the boost hydraulic chamber, directly presses the master piston according to the operation of the brake operation member when the hydraulic pressure of the boost hydraulic chamber decreases. The control piston, which is slidably accommodated in the casing and enables an elastic member to be interposed between the input member and the brake operation member, is fitted to the backup piston so as to be relatively slidable, The control piston is coaxially connected to the rear end of the reaction force piston that faces the front end of the boost hydraulic pressure control chamber formed in the backup piston, and a valve is placed in front of the reaction force piston in the backup piston. The housing is fitted and fixed, and the pressure reducing valve is provided in the reaction force piston by forming a pressure reducing valve hole that leads to the reservoir when retreating. A valve seat and a poppet-type pressure reducing valve body that is spring-biased backward while restricting the retreat limit and is accommodated in the valve housing. The pressure increasing valve is inserted through the front end of the pressure reducing valve body. It is possible to form a pressure increasing valve hole communicating with the boost hydraulic pressure control chamber so that it can be pushed forward by the pressure increasing valve seat provided in the valve housing and the front end of the pressure reducing valve body. And a poppet type pressure increasing valve body housed in the valve housing and spring-biased to the rear side, and a sealing area when the pressure increasing valve body is seated on the pressure increasing valve seat, The pressure-receiving area of the front end of the pressure-increasing valve element that receives the hydraulic pressure in the boosted hydraulic pressure chamber is set to be approximately equal.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect of the invention, the valve housing has a step portion provided on the backup piston facing forward and a pressing member screwed into the backup piston. Is fitted and fixed to the backup piston so that the front end of the pressure-increasing valve body faces the pressing member, and is formed between the pressing member and the valve housing. A communication hole is provided to allow the hydraulic chamber to communicate with the boost hydraulic chamber.

  According to the first aspect of the present invention, the control piston, the reaction force piston, the pressure reducing valve, and the pressure increasing valve can be incorporated in advance in the backup piston slidably accommodated in the casing. The assembly of the force piston, the pressure reducing valve, and the pressure increasing valve to the casing is facilitated. Moreover, the hydraulic pressure acting on both ends of the pressure increasing valve body of the poppet type provided in the pressure increasing valve is substantially equal, the force in the valve opening direction acting on the pressure increasing valve body from the front end of the pressure reducing valve body provided in the pressure reducing valve, and pressure increasing Since the pressure-increasing valve body operates so as to balance the spring force that urges the valve body rearward, the operability of the pressure-intensifying valve can be improved, and the spring urging force that urges the pressure-increasing valve body rearward Only needs to have a weak spring force that causes the pressure-increasing valve body to follow the pressure-reducing valve body, and the spring biasing force that biases the pressure-reducing valve body rearward only causes the pressure-reducing valve body to follow the reaction force piston. The spring force acting on the reaction piston is very weak, and most of the reaction force acting on the reaction piston is based on the hydraulic pressure in the boost hydraulic chamber. The ring can be improved.

  According to the second aspect of the present invention, it is possible to simply configure the hydraulic pressure path for applying the hydraulic pressure of the boost hydraulic chamber to the front end of the pressure increasing valve element.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 8 show a first embodiment of the present invention. FIG. 1 is a brake hydraulic system diagram showing the overall configuration of a vehicle brake device. FIG. 2 shows a master cylinder, a hydraulic booster, and a stroke simulator. FIG. 3 is an enlarged longitudinal sectional view of the master cylinder, FIG. 4 is an enlarged longitudinal sectional view of the hydraulic booster, FIG. 5 is an enlarged view of the main part of FIG. 4, and FIG. 6 is an enlarged longitudinal sectional view of the stroke simulator. 7 is a reaction force characteristic diagram, and FIG. 8 is an action characteristic diagram of the stroke simulator.

  First, in FIG. 1, the brake device for a four-wheel vehicle adjusts the hydraulic pressure of the hydraulic pressure generation source 12 according to a brake operation force input from a master cylinder M that is a tandem type and a brake pedal 11 as a brake operation member. A hydraulic booster 13 that pressurizes and acts on the master cylinder M, and a stroke simulator 14 interposed between the brake pedal 11 and the hydraulic booster 13 are provided.

  Referring also to FIG. 2, the casing 15 common to the master cylinder M and the hydraulic booster 13 includes a bottomed cylindrical first cylinder body 16 closed at the front end and an inward flange portion 17 a at the rear end. A second cylinder body 17 having a cylindrical shape and coaxially coupled to the rear portion of the first cylinder body 16; and a ring-shaped separator 18 sandwiched between the first and second cylinder bodies 16 and 17. And a cylindrical sleeve 19 that has an outward flange 19a sandwiched between the separator 18 and the rear end of the first cylinder body 16 at the rear end and is fitted and fixed to the rear part of the first cylinder body 16. .

  In such a casing 15, in order from the front end side thereof, a first cylinder hole 20 formed at the front inner periphery of the first cylinder body 16, a diameter smaller than the first cylinder hole 20, and an inner periphery of the sleeve 19. The second cylinder hole 21 formed, the third cylinder hole 22 formed on the inner periphery of the separator 18 with a slightly smaller diameter than the second cylinder hole 21, and the second portion at the portion excluding the inward flange portion 17a. A fourth cylinder hole 23 formed on the inner periphery of the cylinder body 17 and having substantially the same diameter as the second cylinder hole 21, and an inner periphery of the inward flange portion 17 a in the second cylinder body 17, than the fourth cylinder hole 23. The fifth cylinder hole 24 formed with a small diameter is arranged so as to be coaxially connected.

  Referring also to FIG. 3, in the master cylinder M, the rear master piston 26, whose rear surface faces the boost hydraulic chamber 25 and spring-biased rearward, slides in the second cylinder hole 21 of the casing 15. The front master piston 27 disposed in front of the rear master piston 26 while being spring-biased rearward is slidably fitted into the first cylinder hole 20 of the casing 15. Further, a rear output hydraulic pressure chamber 28 is formed between the rear master piston 26 and the front master piston 27, and is a disc-shaped seat that is liquid-tightly fitted to the front end portion of the casing 15, that is, the front end portion of the first cylinder body 16. A front output hydraulic pressure chamber 29 is formed between the holding member 30 and the front master piston 27.

  An annular piston-side seal member 31 and a sleeve-side seal member 32 are provided at two positions spaced apart in the axial direction between the rear master piston 26 formed in a bottomed cylindrical shape with the front side opened and the sleeve 19. The piston-side seal member 31 is attached to the rear outer periphery of the rear master piston 26 so as to be in sliding contact with the inner surface of the second cylinder hole 21, and the sleeve-side seal member 32 is retracted from the rear master piston 26. When it is in the limit position, it is mounted on the inner periphery of the sleeve 19 at a position in contact with the outer periphery of the front portion of the rear master piston 26.

  On the other hand, an annular open chamber 33 is formed between the outer periphery of the sleeve 19 and the first cylinder body 16, and both end portions in the axial direction of the annular open chamber 33 are mounted on the outer periphery of the front portion of the sleeve 19. An annular seal member 34 that elastically contacts the inner periphery of the body 16, and an annular seal member 35 that is attached to the rear outer periphery of the sleeve 19 and elastically contacts the inner periphery of the first cylinder body 16. Sealed. In addition, the sleeve 19 has a plurality of communication holes 36 between the seal member 31 and 32 interposed between the sleeve 19 and the rear master piston 26, and the inner periphery of the sleeve 19 and the rear master piston 26. A portion where both ends in the axial direction of the outer periphery are sealed by the seal members 31 and 32 is provided so as to communicate with the annular open chamber 33.

  An annular recess 38 is formed on the outer periphery of the front master piston 27 between the inner periphery of the first cylinder body 16 and forms a rear annular chamber 37. The annular opening chamber 33 communicates with the rear annular chamber 37. A rear opening port 39 communicating with the first cylinder body 16 is provided. As shown in FIG. 1, the rear opening port 39 communicates with the second oil reservoir chamber 42 among the first to third oil reservoir chambers 41, 42, 43 formed in the reservoir 40 independently of each other. The

  A rear lip seal 44 interposed between the rear output hydraulic chamber 28 and the rear annular chamber 37 is arranged on the outer periphery of the front master piston 27 from the rear annular chamber 37 to replenish the rear output hydraulic chamber 28 with brake fluid. A front lip seal 45 interposed between the front output hydraulic chamber 29 and the rear annular chamber 37 is mounted while allowing the brake fluid to flow to the output hydraulic chamber 28 side. Thus, the second cylinder hole 21 formed at the inner periphery of the sleeve 19 has a smaller diameter than the first cylinder hole 20, and the seal diameter of the rear master piston 26 by the piston-side seal member 31 and the sleeve-side seal member 32. Is smaller than the seal diameter of the lip seals 44 and 45 of the front master piston 27.

  A valve hole forming member 49 to which an annular sheet member 48 made of rubber is baked is press-fitted on the outer peripheral portion of the front master piston 27, and the valve hole formed in the central portion is provided with a valve hole forming member 49. A plurality of communication passages 51 for communicating 50 to the rear annular chamber 37 are provided at the rear portion of the front master piston 27.

  A disc-shaped valve body 52 that can be seated on the seat member 48 and close the valve hole 50 regulates the maximum distance between the rear and front master pistons 26 and 27, and the rear and front master pistons 26, 27 is provided integrally near the front end of the rod 54 that constitutes a part of the maximum distance regulating means 53 provided between the two members 27, and the front end of the rod 54 is a valve hole when the valve body 52 is separated from the seat member 48. The brake fluid is inserted into the valve hole 50 so as to allow the brake fluid to flow therethrough.

  The maximum distance regulating means 53 is formed in a bottomed cylindrical shape with the front end closed and is contacted with the rear master piston 26, and is formed in a bottomed cylindrical shape with the rear end closed. A front retainer 56 abutted against the rear end of the part master piston 27; a rear return spring 57 that is contracted between the rear part and the front retainers 55, 56 and biases the rear master piston 26 rearward; The front end closing portion of the retainer 55 and the rod 54 movably penetrating the rear closing end of the front retainer 56 are included.

  The rod 54 is provided at the rear end with an engagement rod 54a that can be engaged with the front end closing portion of the rear retainer 55 from the rear, and can be engaged with the rear end closing portion of the front retainer 56 from the front side. An engagement step portion 54b is provided so as to be located behind the valve body 52. In the rear retainer 55, a guide cylinder 58 for guiding the axial movement of the engagement rod 54a is fitted and fixed.

  According to such a maximum distance regulating means 53, the rear retainer 55 is substantially fixed to the rear master piston 26 by the spring force exerted by the rear return spring 57, and the front force is exerted by the spring force exerted by the rear return spring 57. When the rear retainer 56 is substantially fixed to the front master piston 27 and the rear master piston 26 is in the retreat limit position as shown in FIG. By engaging the end from the rear and engaging step 54b from the front to the rear closed end of the front retainer 56, the maximum distance between the rear and front master pistons 26 and 27 is regulated. At this time, the valve body 52 is separated from the seat member 48 to open the valve hole 50.

  In addition, a valve spring 59 having a smaller spring load than the rear return spring 57 is contracted between the front retainer 56 and the valve body 52, and the valve body as the rear master piston 26 moves forward from the retreat limit position. 52 is seated on the seat member 48 by the spring force of the valve spring 59 to close the valve hole 50.

  An annular front annular chamber 60 is formed between the inner surface of the front end portion of the first cylinder hole 20 and the sheet holding member 30, and a front opening port 61 communicating with the front annular chamber 60 is provided in front of the first cylinder body 16. Provided in the section. As shown in FIG. 1, the front opening port 61 communicates with a third oil sump chamber 43 formed in the reservoir 40. Moreover, on the outer periphery of the seat holding member 30, a lip seal 62 that allows the brake fluid to flow from the front annular chamber 60 to the front output hydraulic chamber 29 side to replenish the front output hydraulic chamber 29 with brake fluid. Is mounted so as to elastically contact the inner periphery of the first cylinder body 16.

  A valve hole forming member 64 on which an annular sheet member 63 made of rubber is baked on the outer periphery is press-fitted into the central portion of the sheet holding member 30, and the valve hole 65 provided in the central portion of the valve hole forming member 64 includes the valve hole 65 provided in the central portion. A plurality of communication grooves 66 that communicate with the front annular chamber 60 are provided on the front surface of the sheet holding member 30.

  A disc-shaped valve body 67 that can be seated on the seat member 63 and close the valve hole 65 regulates the maximum distance between the seat holding member 30 and the front master piston 27, and the front portion of the seat holding member 30 and the front portion. When the valve element 67 is separated from the seat member 63, the front end of the rod 69 is integrally provided near the front end of the rod 69 that constitutes a part of the maximum gap regulating means 68 provided between the master pistons 27. The brake fluid is inserted into the valve hole 65 so as to allow the brake fluid to flow through the valve hole 65.

  The maximum distance regulating means 68 is formed in a bottomed cylindrical shape with the front end closed and is contacted with the front master piston 27, and is formed in a bottomed cylindrical shape with the rear end closed. A front retainer 71 that is in contact with the rear end of the sheet holding member 30 and a front return spring that is contracted between the rear and front retainers 70 and 71 and biases the front master piston 27 rearward. 72 and the rod 69 penetrating through the front closed end of the rear retainer 70 and the rear closed end of the front retainer 71, and the spring load of the front return spring 72 is larger than the spring load of the rear return spring 57. Set low.

  The rod 69 is provided at the rear end with an engagement rod 69a that can be engaged with the front end blocking portion of the rear retainer 70 from the rear, and can be engaged with the rear end blocking portion of the front retainer 71 from the front side. An engagement step portion 69 b is provided so as to be located behind the valve body 67. In the rear retainer 70, a guide cylinder 73 for guiding the axial movement of the engagement rod 69a is fitted and fixed.

  According to such a maximum distance regulating means 68, the rear retainer 70 is substantially fixed to the front master piston 27 by the spring force exerted by the front return spring 72, and the spring exerted by the front return spring 72. The front retainer 71 is substantially fixed to the seat holding member 30 by force, and the engagement rod 69a is attached to the rear retainer 70 in a state where the front master piston 27 is in the retreat limit position as shown in FIG. Engaging the front closed end from the rear and engaging step 69b from the front closed end of the front retainer 71 from the front restricts the maximum distance between the seat holding member 30 and the front master piston 27. At this time, the valve element 67 is separated from the seat member 63 to open the valve hole 65.

  In addition, a valve spring 74 having a smaller spring load than the front return spring 72 is provided between the front retainer 71 and the valve body 67 so that the front master piston 27 moves forward from the retreat limit position. The valve body 67 is seated on the seat member 63 by the spring force of the valve spring 74 and closes the valve hole 65.

  The first cylinder body 16 has a rear output port 77 for outputting the hydraulic pressure of the rear output hydraulic pressure chamber 28 that becomes high pressure according to the forward operation of the rear master piston 26, and the forward operation of the front master piston 27. A front output port 78 that outputs the hydraulic pressure of the front output hydraulic pressure chamber 29 that is high in pressure is provided. Moreover, as shown in FIG. 1, the rear output port 77 is connected to the right front wheel and left rear wheel brakes BA and BB via the first hydraulic pressure control device 79A, and the front output port 78 is connected to the second liquid The pressure control device 79B is connected to the left front wheel and right rear wheel brakes BC and BD.

  The first hydraulic pressure control device 79A includes a normally open solenoid valve 80A interposed between the rear output port 77 and the right front wheel wheel brake BA, and between the rear output port 77 and the left rear wheel wheel brake BB. A normally open solenoid valve 80B, and one-way valves 81A and 81B connected in parallel to the normally open solenoid valves 80A and 80B, respectively, allowing the brake fluid to flow to the rear output port 77 side, A normally closed solenoid valve 83A interposed between the right front wheel brake BA and the first reservoir 82A, and a normally closed solenoid valve 83B interposed between the left rear wheel brake BB and the first reservoir 82A A first return pump 84A for returning the brake fluid pumped from the first reservoir 82A to the rear output port 77 side, and an orifice 85A provided between the first return pump 84A and the rear output port 77 Provided.

  The second hydraulic pressure control device 79B includes a normally open solenoid valve 80C interposed between the front output port 78 and the left front wheel wheel brake BC, and between the front output port 78 and the right rear wheel wheel brake BD. And a one-way valve 81C that is connected in parallel to the two normally open solenoid valves 80C and 80D, respectively, allowing the brake fluid to flow to the front output port 78 side. , 81D, a normally closed solenoid valve 83C interposed between the left front wheel wheel brake BC and the second reservoir 82B, and a normally closed type interposed between the right rear wheel wheel brake BD and the second reservoir 82B. An electromagnetic valve 83D, a second return pump 84B for returning brake fluid pumped up from the second reservoir 82B to the front output port 78 side, and an orifice 85 provided between the second return pump 84B and the front output port 78 Provided with a door.

  The first and second return pumps 84 </ b> A and 84 </ b> B are commonly connected to a single electric motor 86, and both return pumps 84 </ b> A and 84 </ b> B are operated in common by the electric motor 86.

  According to such first and second hydraulic pressure control devices 79A and 79B, the brake hydraulic pressure output from the rear and front output ports 77 and 78 can be freely controlled, and the anti-lock at the time of brake operation is achieved. Brake control, traction control in a non-brake operation state, and the like can be executed by the hydraulic pressure control of the first and second hydraulic pressure control devices 79A and 79B.

  In FIG. 4, the hydraulic booster 13 is built in the stepped cylindrical backup piston 88 slidably accommodated in the casing 15 with the front face facing the boosted hydraulic pressure chamber 25, and the backup piston 88. The pressure regulating valve means 89 is actuated so as to balance the reaction force based on the hydraulic pressure in the boost hydraulic pressure chamber 25 and the brake operating force input from the brake pedal 11 via the stroke simulator 14, thereby controlling the pressure regulating valve means 89. A control piston 90 for adjusting pressure and a reaction force piston 92 interposed between the pressure adjusting valve means 89 and the control piston 90 are provided.

  The backup piston 88 is coaxially connected to the front end of the piston main portion 88a so as to slidably pass through the third cylinder hole 22 and the piston main portion 88a slidably fitted into the fourth cylinder hole 23. A cylindrical pressing portion 88b that is integrally connected, and a cylindrical shape that is coaxially and integrally connected to the rear end of the piston main portion 88a and slidably passes through the fifth cylinder hole 24 and extends rearward from the casing 15. The extension cylinder portion 88c is integrally provided, and the pressing portion 88b can directly contact the rear end of the rear master piston 26 to press the rear master piston 26 forward.

  In addition, a restriction step 88d facing the rear side is formed on the outer periphery of the backup piston 88 between the piston main portion 88a and the extension tube portion 88c, and this restriction step 88d is the rear end of the second cylinder body 17 in the casing 15. The abutting limit position of the backup piston 88 in the casing 15 is regulated by contacting the inward flange portion 17a from the front side.

  In the backup piston 88, annular seal members 93 and 94 that are elastically slidably contacted with the inner periphery of the fourth cylinder hole 23 are attached to the outer periphery of the piston main portion 88a at an axial interval. An annular seal member 95 that elastically slides on the outer periphery of the pressing portion 88b of the backup piston 88 is attached to the periphery. Thus, the third cylinder hole 22 is slightly smaller in diameter than the second and fourth cylinder holes 21 and 23 having substantially the same diameter, and the pressing portion 88b is a seal between the rear master piston 26 and the piston main portion 88a. It is slidably fitted into the third cylinder hole 22 of the casing 15 with a seal diameter smaller than the diameter.

  Between the second cylinder body 17 of the casing 15 and the backup piston 88, the seal member 93 on the front side of the pair of seal members 93 and 94 mounted on the outer periphery of the piston main portion 88a and the separator 18 An annular input chamber 96 sealed at both ends in the axial direction is formed by a seal member 95 mounted on the periphery, and this input chamber 96 is communicated with an input port 97 provided in the second cylinder body 17.

  By the way, when the rear master piston 26 in the master cylinder M is pressed in the forward direction by the pressing portion 88b of the backup piston 88, the volume of the boost hydraulic chamber 25 is increased and the volume of the input chamber 96 is decreased. However, the volume increase amount of the boost hydraulic chamber 25 is set to be substantially the same as the volume decrease amount of the input chamber 96.

  The input port 97 is communicated with the hydraulic pressure source 12 as shown in FIG. Thus, the hydraulic pressure generation source 12 includes a hydraulic pump 98 that draws brake fluid from the first oil reservoir chamber 41 of the reservoir 40, an accumulator 99 connected to the discharge port of the hydraulic pump 98, and the hydraulic pump 98. A relief valve 100 provided between the discharge port and the first oil sump chamber 41 and a hydraulic pressure sensor 101 for detecting the hydraulic pressure of the accumulator 99 to control the operation of the hydraulic pressure pump 98. High-pressure brake fluid that is kept constant is supplied from the hydraulic pressure source 12 to the input port 97, that is, the input chamber 96.

  By the way, a spring 102 accommodated in the boost hydraulic chamber 25 is contracted between the backup piston 88 and the rear master piston 26 in which the retreat limit position in the casing 15 is regulated. Due to the force, the backup piston 88 and the rear master piston 26 are biased in a direction away from each other.

  Thus, in the non-brake operation state, the interval between the front end closing portion of the casing 15 and the rear master piston 26 is regulated to a certain maximum interval by the action of the maximum interval restricting means 53, 68. A gap 91 is formed between the rear master piston 26 and the front end of the backup piston 88 in the retreat limit position so that the rear master piston 26 is opposed to the backup piston 88 from the front. Thus, the spring load of the spring 102 is set to be smaller than the spring loads of the rear return spring 57 and the front return spring 72. The spring 102 causes the rear master piston 26 and the A gap 91 between the backup pistons 88 is maintained.

  Further, in response to the output hydraulic pressure of the hydraulic pressure generating source 12 acting on the input chamber 96, the backward hydraulic pressure acts on the backup piston 88, and the spring force of the spring 102 also moves backward on the backup piston 88. However, it is desirable that the resultant force of the fluid pressure in the backward direction and the spring force in the backward direction by the spring 102 is set to 300 to 1000N.

  In the casing 15, the second cylinder body 17, the first cylinder body 16, and the sleeve 19 are provided with a boost hydraulic pressure input port 103 that communicates with the boost hydraulic pressure chamber 25. 1 is connected to the hydraulic pressure generating source 12 via a normally closed automatic brake pressurizing linear solenoid valve 104 and is connected to a first oil sump chamber 41 of a reservoir 40 as shown in FIG. The pressure reducing linear solenoid valve 105 for cooperation is connected. That is, a normally open type automatic brake pressurizing linear solenoid valve 104 is interposed between the boost hydraulic chamber 25 and the hydraulic pressure generation source 12, and a normally closed regeneration coordination is provided between the boost hydraulic chamber 25 and the reservoir 40. A pressure-reducing linear solenoid valve 105 is interposed.

  Between the piston main portion 88a of the backup piston 88 and the second cylinder body 17 of the casing 15, both ends in the axial direction are sealed by a pair of seal members 93 and 94 mounted on the outer periphery of the piston main portion 88a. An annular output chamber 106 is formed, and a boost hydraulic pressure output port 107 communicating with the output chamber 106 is provided in the second cylinder body 17.

  The boost hydraulic pressure output port 107 is connected to the boost hydraulic pressure input through a normally open type automatic brake pressure-reducing linear solenoid valve 108 and a normally open type pressure adjusting linear solenoid valve 109 connected in series. The automatic one-way valve 110 is connected to the port 103, and the first one-way valve 110 allows the brake fluid to flow from the boost hydraulic pressure output port 107 to the boost hydraulic pressure input port 103. The second one-way valve 111 is connected in parallel to the linear solenoid valve 108 for use, and allows the brake fluid to flow from the boost hydraulic pressure input port 103 to the boost hydraulic pressure output port 107 side. The regenerative cooperation pressurizing linear solenoid valve 109 is connected in parallel.

  In other words, an automatic brake pressure-reducing linear solenoid valve 108 having a first one-way valve 110 connected in parallel is interposed between the output chamber 106 and the boost hydraulic chamber 25, and a second one-way valve 111 is provided. A regenerative cooperation pressurizing linear solenoid valve 109 connected in parallel is interposed.

  In addition, a brake operation amount detection hydraulic pressure sensor 112 is connected between the boost hydraulic pressure output port 107 and the automatic brake pressure-reducing linear solenoid valve 108, and the regeneration cooperation pressurizing linear solenoid valve 109 and boost hydraulic pressure input port 103. A hydraulic pressure sensor 113 for automatic brake feedback control is connected between them.

  Referring also to FIG. 5, the pressure regulating valve means 89 is composed of a pressure increasing valve 116 and a pressure reducing valve 117, and when the output hydraulic pressure of the hydraulic pressure generating source 12 is reduced, the input chamber 96 and the output chamber 106. The output chamber 106 is communicated with the first oil sump chamber 41 of the reservoir 40 and is built in the piston main portion 88 a of the backup piston 88.

  A valve housing 118 comprising a stepped cylindrical housing main body 119 and an end wall member 120 that is liquid-tightly fitted and fixed to the front end of the housing main body 119 is coaxially provided in the piston main portion 88a of the backup piston 88. Mated and fixed. An annular step 121 facing the master cylinder M is provided on the inner surface of the piston main portion 88a, and the valve housing 118 is fitted to the piston main portion 88a from the front until it contacts the step 121. Then, a disc-shaped pressing member 122 that holds the valve housing 118 between the stepped portion 121 and the piston main portion 88 a of the backup piston 88 is screwed. Thus, the spring 102 accommodated in the boost hydraulic chamber 25 is contracted between the rear master piston 26 of the master cylinder M and the pressing member 122.

  On the inner surface of the piston main portion 88a of the backup piston 88 behind the valve housing 118, an annular engagement step portion 123 facing the valve housing 118 side is disposed between the engagement step portion 123 and the valve housing 118. And an annular engagement step portion 124 facing the valve housing side. The engagement step portion 123 is in contact with and engaged with the outer periphery of the rear end portion of a cylindrical sleeve 125 that is liquid-tightly fitted in the piston main portion 88a. The front end of the sleeve 125 is engaged with the engagement step portion 123a. It arrange | positions so that the step part 124 may be continued on the same plane.

  The outer peripheral portions of the ring-shaped elastic member 127 having one surface in contact with the flat plate-like retainer 126 are brought into contact with the front ends of the engagement step portion 124 and the sleeve 125, and the outer peripheral portions of the valve housing 118 and the retainer 126 are contacted. A holding spring 128 is contracted between the one surface. Accordingly, the outer peripheral portion of the elastic member 127 is sandwiched between the engagement step portion 124 and the front ends of the sleeve 125 and the outer peripheral portion of the retainer 126.

  In the piston main portion 88a of the backup piston 88, between the valve housing 118 and the elastic member 127 and the retainer 126, a hydraulic pressure control chamber 130 is provided so as to exert a hydraulic pressure on one surface of the elastic member 127. The boost hydraulic pressure control chamber 130 communicates with the output chamber 106 through a plurality of communication holes 129... Provided in the piston main portion 88a.

  Referring also to FIG. 6, the control piston 90 is formed in a stepped bottomed cylindrical shape with the front end closed, and is relative to the extension cylinder portion 88 c of the backup piston 88 and the rear portion of the piston main portion 88 a. It is slidably fitted. In addition, a retaining ring 133 is attached to the inner surface of the rear end of the extended cylindrical portion 88c of the backup piston 88, and the rear end of the control piston 90 abuts against the retaining ring 133, so that the backup piston 88 of the control piston 90 is separated from the backup piston 88. The withdrawal is prevented.

  An annular seal member 134 that elastically contacts the inner periphery of the rear portion of the piston main portion 88a of the backup piston 88 is mounted on the outer periphery of the front portion of the control piston 90. The rear portion of the piston main portion 88a is attached to the rear portion of the piston main portion 88a. A release chamber 135 that is sealed to the outside by the seal member 134 is formed so as to face the front end of the control piston 90. On the other hand, the second cylinder body 17 in the casing 15 is provided with a release port 136 that communicates with the first oil sump chamber 41 in the reservoir 40 and a release passage 137 that communicates with the release port 136, and opens to the inner surface of the fourth cylinder hole 23. An annular recess 138 is provided so as to communicate with the release passage 137. In addition, the backup piston 88 is provided with a plurality of communication holes 139 that allow the release chamber 135 to communicate with the annular recess 138 at all times, and an annular ring mounted on the outer periphery of the backup piston 88 in front of the annular recess 138. The annular recess 138 is sealed from the front and the back by a seal member 94 and an annular seal member 141 that is attached to the inner surface of the fifth cylinder hole 24 and is in sliding contact with the outer periphery of the extension cylinder portion 88 c of the backup piston 88. In this way, the release chamber 135 is always in communication with the first oil sump chamber 41 of the reservoir 40.

  The reaction force piston 92 is formed between a small diameter piston portion 92a facing the front end of the boost hydraulic pressure control chamber 130 and an annular step portion 92c facing the boost hydraulic pressure control chamber 130 between the small diameter piston portion 92a. Thus, a large-diameter piston portion 92b that is coaxially connected to the rear end of the small-diameter piston portion 92a is integrally provided. The small-diameter piston portion 92a penetrates the elastic member 127 in a liquid-tight and slidable manner and penetrates the retainer 126 in an axially movable manner, and the large-diameter piston portion 92b is slidably fitted to the sleeve 125. The

  Thus, the inner peripheral portion of the elastic member 127 where the hydraulic pressure in the boost hydraulic pressure control chamber 130 acts on one side is deformed when the hydraulic pressure in the boost hydraulic pressure control chamber 130 becomes equal to or higher than a predetermined pressure. The piston 92 is pressed against the annular step portion 92c, and the inner peripheral portion of the other surface of the elastic member 127 is disposed to face the annular step portion 92c.

  Further, the rear end of the reaction force piston 92 is coaxially abutted with the front end of the control piston 90, and between the flange 92d provided at the rear end of the reaction force piston 92 and the backup piston 88. A spring 142 that exerts a spring force that causes the reaction force piston 92 to contact the front end of the control piston 90 is contracted, and the spring load of the spring 142 is such that the control piston 90 follows the reaction force piston 92. It is set to a small value.

  The reaction force piston 92 has an insertion hole 143 that extends coaxially with the front end communicating with the boost hydraulic pressure control chamber 130, and an axial hole portion 144 a that is coaxial with the insertion hole 143, and communicates with the release chamber 135. A through-hole 144 is provided, and a flange-like pressure reducing valve seat 146 that projects radially inward between the insertion hole 143 and the shaft hole 144a is coaxial with the insertion hole 143 and the shaft hole 144 for pressure reduction. The valve hole 145 is provided so as to be formed.

  The pressure reducing valve 117 is arranged in front of the reaction force piston 92 so that the pressure reducing valve seat 146 and the rear end can be seated on the valve seat 146, and is spring-biased rearward while restricting the backward limit. And a poppet-type pressure reducing valve body 147, and the rear portion of the pressure reducing valve body 147 forms an annular orifice 148 in front of the pressure reducing valve seat 146 and the reaction force piston 92. Then, it is inserted into the insertion hole 143 coaxially.

  A cylindrical guide tube 119 a extending rearward in the boost hydraulic pressure control chamber 130 is integrally provided at the rear portion of the housing main body 119 in the valve housing 118 and is accommodated in the boost hydraulic pressure control chamber 130. The pressure reducing valve body 147 is held in the boost hydraulic pressure control chamber 130 so as to be slidable in the axial direction on the guide cylinder 119a.

  A retaining ring 149 that abuts against the pressure reducing valve body 147 from the rear side and restricts the backward limit of the pressure reducing valve body 147 is attached to the rear end portion of the guide cylinder 119a. Further, a rectifying member 150 that penetrates the front portion of the pressure reducing valve body 147 so as to be axially movable is provided in the housing main body 119 of the valve housing 118 so as to form a front end wall of the guide cylinder 119a. A pressure reducing valve spring 151 is provided between the rectifying member 150 and the pressure reducing valve body 147 so as to bias the pressure reducing valve body 147 toward the rear. It is reduced.

  Between the reaction force piston 92 and the sleeve 125 with the rear end facing the release chamber 135, the release chamber is opened from the through hole 144 when the reaction force piston 92 is not operated when the brake pedal 11 is not operated. A variable throttle mechanism 154 is provided for restricting the flow of brake fluid from the through hole 144 to the release chamber 135 when the reaction force piston 92 is actuated when the brake pedal 11 is operated.

  The through hole 144 includes a shaft hole portion 144a provided in the reaction force piston 92 such that the front end is passed through the pressure reducing valve hole 145 and the rear end is closed at the front end of the control piston 90, and the shaft hole portion 144a The variable throttle mechanism 154 includes a rear end portion of the sleeve 125 and a lateral hole portion 144b... And a plurality of lateral hole portions 144b that are continuous with the intermediate portion and open to the outer surface of the reaction force piston 92. Is done.

  In addition, a taper-shaped enlarged diameter portion 125 a that increases in diameter toward the rear is formed on the inner periphery of the rear end portion of the sleeve 125.

  In the valve housing 118, a valve chamber 155 is formed between the inward flange portion 119 b and the end wall member 120. Further, an annular recess 156 is provided on the outer periphery of the housing main body 119 in the valve housing 118, and the housing main body 119 is provided with a plurality of communication holes 157, which allow the valve chamber 155 to communicate with the annular recess 156. A plurality of communication passages 158 extending in the radial direction of the second cylinder body 17 so as to allow the inner end to pass through the annular recess 156 pass through the piston main portion 88 of the backup piston 88 so that the outer end communicates with the input chamber 96. The valve chamber 155 communicates with the hydraulic pressure generation source 12. In addition, a pair of annular seal members 159 and 160 sandwiching the annular recess 156 between the valve housing 118 and the outer periphery of the housing main body 119 elastically contact the inner periphery of the piston main portion 88a. It is put on.

  The pressure increasing valve 116 is formed on the inner periphery of the inward flange portion 119b of the valve housing 118 and faces the valve chamber 155. The pressure increasing valve 116 can be seated on the pressure increasing valve seat 161. 155 and a poppet type pressure-increasing valve body 162 housed in 155. The pressure-increasing valve seat 161 forms a pressure-increasing valve hole 163 into which the front end of the pressure-reducing valve body 147 can be inserted. The pressure-increasing valve seat 161 is spring-backed by a valve spring 177 contracted between the valve housing 118. The urged pressure-increasing valve body 162 is accommodated in the valve chamber 155 so that it can be pushed forward at the front end of the pressure-reducing valve body 147 inserted through the pressure-increasing valve hole 163.

  By the way, the pressure-increasing valve body 162 is integrally provided with a rod portion 162a that penetrates the central portion of the end wall member 120 in the valve housing 118 in a liquid-tight manner and is movable in the axial direction, and the front end of the rod portion 162a. Faces the hydraulic chamber 164 formed between the end wall member 120 and the pressing member 122. The holding member 122 is provided with a communication hole 165 that allows the hydraulic pressure chamber 164 to communicate with the boosted hydraulic pressure chamber 25, and the hydraulic pressure of the boosted hydraulic pressure chamber 25 is at the front end of the pressure increasing valve body 162. It will work towards the back. Moreover, the front pressure receiving area of the pressure increasing valve body 162 that receives the hydraulic pressure in the boost hydraulic pressure chamber 25 and the seal area when the pressure increasing valve body 162 is seated on the pressure increasing valve seat 161 are set to be approximately equal. . That is, the diameter of the rod portion 162a and the diameter of the seating portion of the pressure-increasing valve body 162 on the pressure-increasing valve seat 161 are set to be substantially equal.

  By the way, when the pressure increasing valve 116 is opened, the brake fluid in the valve chamber 155 communicating with the hydraulic pressure generating source 12 flows from the pressure increasing valve hole 163 to the boost hydraulic pressure control chamber 130 side. The rectifying member 150 urged by the pressure-reducing valve spring 151 so that the valve body 147 penetrates in an axially movable manner and abuts against the inward flange portion 119b is boosted in the vicinity of the pressure-increasing valve hole 163. It is disposed in the pressure control chamber 130.

  Thus, the rectifying member 150 includes a disc portion 150a facing the inward flange portion 119b and the inward flange portion 119b so that the pressure reducing valve body 147 penetrates the central portion in an axially movable manner. The brake fluid flowing from the pressure increasing valve hole 163 toward the boost hydraulic pressure control chamber 130 is composed of a plurality of protrusions 150b... Projecting from the disk portion 150a so as to abut. It collides with the part 150a and changes the direction of the flow, and is rectified so as to flow radially between the disk part 150a and the inward flange part 119b and flows into the boost hydraulic pressure control chamber 130.

  In such a hydraulic booster 13, a brake operation input from the brake pedal 11 is input to the control piston 90 via the stroke simulator 14, and a forward pressing force acts on the reaction force piston 92 from the control piston 90. . Thus, when the pressure reducing valve body 147 is seated on the pressure reducing valve seat 146 as the reaction force piston 92 advances, the pressure reducing valve 117 is closed and the boost hydraulic pressure control chamber 130 and the reservoir 40 are disconnected. Further, the control piston 90, the reaction force piston 92, and the pressure reducing valve body 147 further move forward, so that the pressure increasing valve body 162 is separated from the pressure increasing valve seat 161, so that the pressure increasing valve 116 is opened and hydraulic pressure is generated. The output hydraulic pressure of the source 12 acts on the boost hydraulic pressure control chamber 130. In the closed state of the pressure reducing valve 117, the hydraulic pressure in the boost hydraulic pressure control chamber 130, that is, the boost hydraulic pressure chamber 25 acts on the front portion of the reaction force piston 92, and the brake operation input from the brake pedal 11; The reaction force piston 92 and the control piston 90 are retracted so that the hydraulic pressure based on the hydraulic pressure in the boost hydraulic pressure control chamber 130 is balanced, so that the pressure reducing valve 117 is opened and the pressure increasing valve 116 is closed. By repeatedly opening and closing the pressure increasing valve 116 and the pressure reducing valve 117, the output hydraulic pressure of the hydraulic pressure generating source 12 is adjusted to the boost hydraulic pressure corresponding to the brake operation input from the brake pedal 11, and the boost hydraulic pressure control is performed. It acts on the chamber 130, that is, the boosted hydraulic pressure chamber 25.

  The stroke simulator 14 includes an input piston 166 as an input member accommodated in the control piston 90 so as to be axially slidable, and an elastic body 167 as an elastic member interposed in series between the input piston 166 and the control piston 90. And a coil spring 168, and is accommodated in the control piston 90 while opening the inside of the control piston 90 to the atmosphere.

  The input piston 166 is slidably fitted to the rear portion of the control piston 90 so as to be regulated by a retaining ring 169 attached to the rear end portion of the control piston 90 and is connected to the brake pedal 11. The front end portion of the input rod 170 is connected to the input piston 166 so as to be able to swing. That is, a brake operating force corresponding to the operation of the brake pedal 11 is input to the input piston 166 via the input rod 170, and the input piston 170 moves forward in response to the input of the brake operating force.

  The elastic body 167 is formed in a cylindrical shape by an elastic material such as rubber. The elastic body 167 and the metal coil spring 168 in which the spring load is set smaller than that of the elastic body 167 are the input piston 166. In addition, the intermediate transmission member 171 is interposed in series between the control piston 90 via the intermediate transmission member 171, and the intermediate transmission member 171 extends in the coil spring 168 and a disk portion 171 a slidably fitted to the control piston 90. And a bottomed cylindrical portion 171b integrally connected to the disk portion 171a.

  The rear portion of the guide shaft 172 is coaxially press-fitted and fixed to the central portion of the input piston 166, and the front portion of the guide shaft 172 can move in the axial direction along the central portion of the disk portion 171a of the intermediate transmission member 171. And is slidably fitted to the bottomed cylindrical portion 171b of the intermediate transmission member 171.

  The elastic body 167 is interposed between the disk portion 171a of the intermediate transmission member 171 and the input piston 166 in a state in which bending to the inner peripheral side is restricted by fitting the guide shaft 172. It is possible to elastically contact the inner periphery of the control piston 90 by bending so as to expand the diameter according to the action of the axial compression force accompanying the forward movement of the piston 166.

  The coil spring 168 is provided between the disk portion 171a of the intermediate transmission member 171 and the front end closing portion of the control piston 90, and the coil spring 168 applies an external force when the input piston 166 is in the retreat limit. It is in a slightly contracted state from no natural state. That is, the elastic body 167 is in a state in which a load from the coil spring 168 is applied in advance.

  By the way, the front end closing portion of the bottomed cylindrical portion 171b in the intermediate transmission member 171 is transparent to prevent the inside of the bottomed cylindrical portion 171b from being pressurized or depressurized as the guide shaft 172 moves forward or backward. A hole 173 is provided. Further, in order to open the inside of the control piston 90 to the atmosphere, an open groove 174 is provided on the outer periphery of the disk portion 171 a in the intermediate transmission member 171, and an open groove 175 is also provided on the outer periphery of the input piston 166. Further, a sealed space is not formed between the control piston 90 and the backup piston 88 on the rear side of the seal member 134 that is mounted on the outer periphery of the control piston 90 and is in sliding contact with the inner surface of the extension cylinder portion 88 c of the backup piston 88. A through-hole 176 is provided in the control piston 90.

  Next, the operation of the first embodiment will be described. The tandem master cylinder M has a rear output between the rear master piston 26 facing the rear surface of the boost hydraulic chamber 25 and the rear master piston 26. A front master piston 27 that forms a hydraulic pressure chamber 28 and has a front faced to the front output hydraulic pressure chamber 29 is slidably accommodated in the casing 15. The backup piston 88 whose front limit is restricted while facing the front surface of the chamber 25 can directly press the rear master piston 26 from the rear according to the operation of the brake pedal 11 when the hydraulic pressure in the boost hydraulic chamber 25 is lowered. The hydraulic pressure in the boost hydraulic pressure chamber 25 is determined by the operation of the hydraulic pressure booster 13 according to the brake operation of the brake pedal 11 when the hydraulic pressure output from the hydraulic pressure generating source 12 is adjusted. The pressure is adjusted to the boost hydraulic pressure corresponding to the rake operation input, and the seal diameter of the rear master piston 26 to the casing 15 is set smaller than the seal diameter of the front master piston 27 to the casing 17. ing.

  Accordingly, the volume change amount of the rear output hydraulic chamber 28 with respect to the stroke of the rear master piston 26 can be set relatively large. When the hydraulic pressure in the boost hydraulic chamber 25 is lowered, the rear master piston 26 is operated by the backup piston 88. When the pressure is directly pressed, the operation amount of the brake pedal 11, that is, the hydraulic pressure change amount of the rear output hydraulic chamber 28 with respect to the stroke of the backup piston 88 and the rear master piston 26 can be made relatively large, and the braking effect can be enhanced.

  Further, the backup piston 88 has a piston main part 88a slidably fitted to the casing 15 with a seal diameter substantially the same as the seal diameter of the rear master piston 26, and a seal diameter of the rear master piston 26 and the piston main part 88a. A small seal diameter is slidably fitted to the casing 15 and can press against the rear end of the rear master piston 26, and a pressing portion 88b coaxially connected to the front end of the piston main portion 88a. An annular input chamber 96 sealed at both ends in the axial direction by seal members 93 and 95 interposed between the piston main portion 88 a and the pressing portion 88 b and the casing 15 is provided in the hydraulic pressure generation source 12. It is formed between the backup piston 88 and the casing 15 so as to communicate with the hydraulic pressure generation source 12 when the output hydraulic pressure is reduced. The force chamber 96 and the output chamber 106 connected to the boosted hydraulic pressure chamber 25 are communicated with each other and the output chamber 106 is communicated with the reservoir 40 so as to be interposed between the input chamber 96 and the output chamber 106. The pressure regulating valve means 89 constituting a part of the pressure booster 13 is built in the backup piston 88, and the volume increase amount of the boost hydraulic chamber 25 when the rear master piston 26 is pushed in the forward direction by the pushing portion 88b is inputted. The volume reduction amount of the chamber 96 is set substantially the same.

  Accordingly, when the hydraulic pressure in the input chamber 96, that is, the hydraulic pressure of the hydraulic pressure generation source 12 decreases, the hydraulic pressure that presses the backup piston 88 toward the backward limit decreases, so that the backup piston 88 is advanced in accordance with the operation of the brake pedal 11. The pressing portion 88b of the front portion of the backup piston 88 is brought into contact with the rear master piston 26 with a gap between the inner surface of the sliding contact portion of the rear master piston 26 with respect to the casing 15, and the rear master piston. By advancing 26, the brake fluid pressure boosted from the master cylinder M can be output. When the backup piston 88 and the rear master piston 26 move forward, the piston main portion 88a and the rear master piston 26 of the backup piston 88 have substantially the same seal diameter, and the pressing portion 88b of the backup piston 88 is the rear master piston 26. The volume increase amount of the boost hydraulic pressure chamber 25 when the pressure is pushed in the forward direction is set to be substantially the same as the volume decrease amount of the input chamber 96, and the pressure regulating valve means is provided between the boost hydraulic pressure chamber 25 and the input chamber 96. 89, the hydraulic pressure in the boosted hydraulic pressure chamber 25 is not increased when the backup piston 88 and the rear master piston 26 move forward. That is, with a simple configuration with a reduced number of parts, it is possible to avoid an increase in the hydraulic pressure in the boost hydraulic pressure chamber 25 when the backup piston 88 moves forward.

  Further, a spring 102 is provided between the backup piston 88 and the rear master piston 26 whose rearward limit position within the casing 15 is regulated, so that the pistons 88 and 26 are separated from each other. When the backup piston 88 is advanced by the brake pedal 11 in accordance with the decrease in the hydraulic pressure, an invalid stroke can be secured.

  Moreover, the hydraulic pressure in the backward direction acting on the backup piston 88 in response to the output hydraulic pressure of the hydraulic pressure generating source 12 acting on the input chamber 96 and the spring attached to urge the backup piston 88 in the backward direction by the spring 102. Since the resultant force with the force is set to 300 to 1000 N, the backup piston 88 can be stably held at the retreat limit position when the hydraulic pressure source 12 is operating normally. That is, since the force for biasing the backup piston in the backward direction is 300 N or more, the backup piston 88 is reliably moved in the backward direction in consideration of the output hydraulic pressure of the hydraulic pressure source 12 and the sliding resistance of the backup piston 88. The rear master piston 26 of the master cylinder M can be prevented from being pushed in by setting the force for biasing the backup piston 88 in the backward direction to 1000 N or less. .

  By the way, a normally closed automatic brake pressurizing linear solenoid valve 104 is interposed between the hydraulic pressure generating source 12 and the boost hydraulic chamber 25, and between the output chamber 106 and the boost hydraulic chamber 25 is normally The open-type automatic brake pressure-reducing linear solenoid valve 108 is connected in parallel to the automatic brake pressure-reducing linear solenoid valve 108 so as to allow the brake fluid to flow from the output chamber 106 to the boost hydraulic pressure chamber 25 side. The first one-way valve 110 is interposed, and the automatic brake pressurizing linear solenoid valve 104 and the automatic brake depressurizing linear solenoid valve are also operated when the brake pedal 11 is not operated, that is, when the pressure regulating valve means 89 is not operated. The brake fluid pressure is applied to the wheel brakes BA to BD in the non-brake operation state by adjusting the hydraulic pressure in the boost hydraulic chamber 25 by controlling the opening and closing of 108. It is possible to perform automatic brake control in the. Moreover, when the brake pedal 11 is operated while the automatic brake pressure-reducing linear solenoid valve 108 is closed during automatic braking, the pressure regulating valve means 89 is activated, and the liquid pressure higher than the hydraulic pressure in the boost hydraulic pressure chamber 25 is reached. When pressure is generated in the output chamber 106, the hydraulic pressure in the output chamber 106 can be applied to the boosted hydraulic pressure chamber 25 via the first one-way valve 110, and the master cylinder is operated in the same manner as during normal brake operation. M can be activated.

  In addition, a normally closed regenerative coordination pressure reducing linear solenoid valve 105 is interposed between the boost hydraulic chamber 25 and the reservoir 40, and a normally open regeneration coordination is provided between the output chamber 106 and the boost hydraulic chamber 25. And a second pressure linear solenoid valve 109 connected in parallel to the pressure regenerative cooperation pressure linear solenoid valve 109 so as to allow the brake fluid to flow from the boost hydraulic pressure chamber 25 to the output chamber 106 side. Since the one-way valve 111 is interposed, the boosting hydraulic pressure chamber 25 is controlled by opening and closing the regeneration linear pressurizing linear solenoid valve 109 and the regeneration cooperative depressurizing linear solenoid valve 105 during regeneration in the brake operation state. By adjusting the hydraulic pressure, the brake hydraulic pressure that is offset from that during normal braking can be output from the master cylinder M, and the regenerative coordination pressure linear solenoid valve 109 is closed. Sometimes when returning the brake pedal 11, it is possible to release the hydraulic pressure of the boosted hydraulic pressure chamber 25 via the second one-way valve 111 to the reservoir 40 side.

  The casing 15 is fitted and fixed in the first cylinder body 16 so that the front master piston 27 is slidably fitted and the rear master piston 26 is slidably fitted. And a cylindrical sleeve 19 which forms an annular open chamber 33 communicating with the reservoir 40 between the first cylinder body 16 and a rear master piston 26 slidably fitted to the sleeve 19. And an annular piston-side seal member 31 and a sleeve-side seal member 32 are interposed at two positions spaced apart in the axial direction between the sleeve 19 and the outer periphery of the rear master piston 26 and the inner periphery of the sleeve 19. The sleeve 19 is provided with a communication hole 36 for allowing the seal portions 31 and 32 to be sealed at both ends in the axial direction to the annular open chamber 33.

  For this reason, the piston side seal member 31 on the boost hydraulic chamber 25 side of the pair of the seal members 31 and 32 interposed between the sleeve 19 constituting the part of the casing 15 and the rear master piston 26 is sealed. When the function cannot be performed, the brake fluid in the boost hydraulic chamber 25 is returned to the reservoir 40 between the rear master piston 26 and the sleeve 19, the communication hole 36 and the annular open chamber 33. At this time, since the backup piston 88 directly presses the rear master piston 26 in accordance with the decrease in the hydraulic pressure in the boost hydraulic chamber 25, it becomes impossible to obtain the boost hydraulic pressure, but it is connected to the tandem master cylinder M. The wheel brakes BA to BD are braked by two brake hydraulic systems.

  Further, when the sleeve side seal member 32 on the rear output hydraulic pressure chamber 28 side of both the seal members 31 and 32 cannot perform the sealing function, the brake fluid in the rear output hydraulic pressure chamber 28 is transferred to the rear master piston 26. And between the sleeve 19, the communication hole 36 and the annular open chamber 33, and then returned to the reservoir 40. At this time, the brake hydraulic pressure is applied to the wheel brakes BA and BB of the brake hydraulic system connected to the rear output hydraulic chamber 28. Although it cannot be obtained, the front master piston 27 is boosted in response to the hydraulic pressure in the boost hydraulic chamber 25 acting on the rear master piston 26, and the brake fluid connected to the front output hydraulic chamber 29. The brake fluid pressure boosted by the pressure system can be applied to the wheel brakes BC and BD.

  That is, when one of the pair of seal members 31 and 32 interposed between the sleeve 19 and the rear master piston 26 does not perform the sealing function, the operating state of each wheel brake BA to BD changes. It becomes possible to clearly detect which of the seal members 31 and 32 is damaged.

  The piston-side seal member 31, which is one of the seal members 31, 32, is mounted on the rear outer periphery of the rear master piston 26, and the sleeve-side seal member 32, which is the other of the seal members 31, 32, is in the retreat limit. Since it is mounted on the inner periphery of the sleeve 19 so as to contact the front outer periphery of the rear master piston 26, the axial length of the sleeve 19, that is, the axial length of the casing 15, regardless of the stroke of the rear master piston 26. A pair of seal members 31 and 32 can be interposed between the rear master piston 26 and the sleeve 19 while avoiding the extension.

  Further, in the non-brake operation state, the rear master piston 26 is rearwardly moved by the rear return spring 57 while the distance between the front end closing part of the casing 15 is restricted to a constant maximum distance by the action of the maximum distance restriction means 53 and 68. The rear master piston 26 approaches the backup piston 88 from the front between the rear end of the rear master piston 26 in this state and the front end of the backup piston 88 in the retreat limit position. A gap 91 is formed so as to face each other. With such a gap 91, axial tolerances on the master cylinder M side and the backup piston 88 side can be absorbed, and the front return spring 74 and the rear master piston 26 that urge the front master piston 27 to the rear side. It is possible to avoid compressing the rear return spring 57 that is biased rearward so that the spring load is equal to or greater than the set load, and to avoid an increase in the invalid stroke of the brake pedal 11.

  Moreover, the spring 102 having a smaller spring load than the rear return spring 57 is compressed between the backup piston 88 and the rear master piston 26 so as to urge the rear master piston 26 forward, so that the brake pedal 11 In this non-operating state, the gap 91 between the rear master piston 26 and the backup piston 88 can be maintained such that the rear and front master pistons 26 and 27 do not move to the side in contact with the backup piston 88.

  The hydraulic booster 13 includes the backup piston 88, the pressure regulating valve means 89 built in the backup piston 88, the reaction force based on the hydraulic pressure in the boost hydraulic chamber 25, and the brake pedal 11 through the stroke simulator 14. A control piston 90 that operates so as to balance the brake operation force input in this manner to adjust the pressure regulating valve means 89, and a reaction force piston 92 interposed between the pressure regulating valve means 89 and the control piston 90. The pressure regulating valve means 89 is a boost hydraulic pressure control chamber 130 connected to the boost hydraulic pressure chamber 25 so as to open when the control piston 90 moves forward and close when the control piston 90 moves backward. The pressure increasing valve 116 interposed between the hydraulic pressure generation sources 12 and the control piston 90 are closed when the control piston 90 moves forward and the control piston 90 moves backward. Composed of the pressure reducing valve 117 so as to be opened is interposed between the boosted hydraulic pressure control chamber 130 and the reservoir 40. In addition, the control piston 90 is fitted to the backup piston 88 so as to be relatively slidable, and the control piston 90 is disposed at the rear end of the reaction force piston 92 that faces the boost hydraulic pressure control chamber 130 formed in the backup piston 88. The valve housing 118 is fitted and fixed in the backup piston 88 in front of the reaction force piston 92, and the pressure reducing valve 117 forms a pressure reducing valve hole 145 that communicates with the reservoir 40 when retreating. A pressure reducing valve seat 146 provided on the force piston 92 and a poppet type pressure reducing valve body 147 which is spring-biased rearward while restricting the retreat limit and is accommodated in the valve housing 118, The pressure increasing valve hole 163 communicating with the boost hydraulic pressure control chamber 130 is formed so that the front end of the pressure reducing valve body 147 can be inserted, and the valve housing 118 is formed. A pressure-increasing valve seat 161 provided, and a poppet-type pressure-increasing valve body 162 that can be pushed forward by the front end of the pressure-reducing valve body 147 and is housed in the valve housing 118 and spring-biased rearward. It consists of.

  Therefore, it is possible to incorporate in advance the pressure regulating valve means 89 including the control piston 90, the reaction force piston 92, the pressure reducing valve 116, and the pressure increasing valve 117 in the backup piston 88 slidably accommodated in the casing 15. The assembly of the control piston 90, the reaction force piston 92, and the pressure regulating valve means 89 to the casing 15 is facilitated.

  In addition, since the sealing area when the pressure increasing valve body 162 is seated on the pressure increasing valve seat 161 and the front end pressure receiving area of the pressure increasing valve body 162 that receives the hydraulic pressure of the boost hydraulic pressure chamber 25 are set to be substantially equal. The fluid pressure acting on both ends of the poppet type pressure increasing valve body 162 provided in the pressure valve 116 is substantially equal, and the force in the valve opening direction acting on the pressure increasing valve body 162 from the front end of the pressure reducing valve body 147 provided in the pressure reducing valve 117. Since the pressure-increasing valve body 162 operates so as to balance the spring force that urges the pressure-increasing valve body 162 backward, the operability of the pressure-increasing valve 116 can be improved. The spring urging force for urging the pressure-increasing valve body 162 rearward may be a weak spring force that causes the pressure-increasing valve body 162 to follow the pressure-reducing valve body 147. Since the spring urging force to be applied may be a weak spring force that causes the pressure reducing valve body 147 to follow the reaction force piston 92, the spring force acting on the reaction force piston 92 becomes very weak, and the reaction force piston 92 The reaction force feeling can be improved by assuming that most of the reaction force acting is based on the hydraulic pressure in the boost hydraulic chamber 25.

  Further, the valve housing 118 is fitted and fixed to the backup piston 88 so as to be sandwiched between a step portion 121 provided on the backup piston 88 facing forward and a pressing member 122 screwed to the backup piston 88. The pressure member 122 has a communication hole through which the hydraulic pressure chamber 164 formed between the pressure member 122 and the valve housing 118 communicates with the boosted hydraulic pressure chamber 25 so as to face the front end of the pressure-increasing valve body 162. Since 165 is provided, it is possible to simply configure a hydraulic pressure path in which the hydraulic pressure of the boost hydraulic pressure chamber 25 is applied to the front end of the pressure increasing valve body 162.

  The reaction force piston 92 is attached to the rear end of the small diameter piston portion 92a via a small diameter piston portion 92a that faces the front end of the boost hydraulic pressure control chamber 130 and an annular step portion 92c that faces the boost hydraulic pressure control chamber 130 side. A pressure reducing valve seat 146 is provided coaxially on the reaction force piston 92 so that the pressure reducing valve hole 145 leading to the reservoir 40 faces the central portion. The pressure-reducing valve body 147 that is spring-biased toward the pressure-reducing valve seat 146 while the retreat limit is regulated is housed in the boost hydraulic pressure control chamber 130, and the hydraulic pressure in the boost hydraulic pressure control chamber 130 acts on one side. The other surface inner peripheral portion of the elastic member 127 that is arranged so as to squeeze and penetrate the small-diameter piston portion 92a of the reaction force piston 92 in a liquid-tight and slidable manner has a predetermined hydraulic pressure in the boost hydraulic pressure control chamber 130. When the pressure exceeds In order to form pressed against the annular step 92c during forward of the reaction piston 92, it is disposed opposite to the annular step 92c.

  Therefore, the pressure reducing valve seat 146 provided in the reaction force piston 92 connected to the control piston 90 and the pressure reducing valve body 147 housed in the boost hydraulic pressure control chamber 130 facing the front end of the reaction force piston 92 are reduced. The structure of the pressure reducing valve 117 can be simplified by constituting the valve 117. Moreover, the reaction force acting on the reaction force piston 92 includes a low load stage in which the hydraulic pressure of the boost hydraulic pressure control chamber 130 acts on the narrow pressure receiving surface of the small diameter piston portion 92a provided in the reaction force piston 92, and the boost hydraulic pressure. The hydraulic pressure in the control chamber 130 changes not only in the narrow pressure-receiving surface of the small-diameter piston portion 92a but also in the high load stage that acts on the annular step portion 92c via the deformed elastic member 127, as shown in FIG. In addition, an ideal brake characteristic can be obtained by changing the boost hydraulic pressure generated in the boost hydraulic chamber 25 in two stages according to the operation input of the brake pedal 11.

  By the way, the pressure increasing valve 116 is capable of being pushed forward when the control piston 90 advances, and the pressure increasing valve seat 161 forming the pressure increasing valve hole 163 communicating with the boost hydraulic pressure control chamber 130. The pressure-increasing valve body 162 includes a pressure-increasing valve body 162 that is spring-biased on the side seated on the pressure-valve valve seat 161. Since the rectifying member 150 that rectifies the brake fluid flowing into the boost hydraulic pressure control chamber 130 from the hole 163 is disposed, the high-pressure brake fluid from the hydraulic pressure generation source 12 increases as the pressure increase valve 116 is opened. When flowing into the boost hydraulic pressure control chamber 130 from the pressure valve hole 163, the brake fluid is rectified by the rectifying member 150, and the generation of operating noise and pulsating sound associated with the operation of the pressure increasing valve 116 can be suppressed.

  The reaction force piston 92 has an insertion hole 143 extending coaxially with the front end communicating with the boost hydraulic pressure control chamber 130 and a shaft hole 144a coaxial with the insertion hole 143. A hole 144 is provided, and a bowl-shaped pressure reducing valve seat 146 that projects radially inward between the insertion hole 143 and the shaft hole portion 144a is provided. The pressure reducing valve seat 146 cooperates with the pressure reducing valve seat 146 to reduce the pressure. The rear portion of the pressure-reducing valve body 147 constituting the valve 117 is inserted into the insertion hole 143 so as to form an annular orifice 148 in front of the pressure-reducing valve seat 146 and the reaction force piston 92. Therefore, when the high pressure in the boost hydraulic pressure control chamber 130 is released to the release chamber 135 as the pressure reducing valve 117 is opened, the pressure reducing valve 117 is formed between the pressure reducing valve body 147 and the reaction force piston 92. After being preliminarily throttled by the annular orifice 148, the narrow flow path between the pressure reducing valve body 147 and the pressure reducing valve seat 146 is circulated. It is possible to suppress the generation of an operating sound at the pressure reducing valve 117 due to a simple change.

  Further, the reaction force piston 92 is provided with a through hole 144 for allowing the boost hydraulic pressure control chamber 130 to communicate with the release chamber 135 when the pressure reducing valve 117 is opened, and the reaction force piston 92 is slidably fitted. When the reaction force piston 92 is not operated when the brake pedal 11 is not operated, the brake is opened from the through hole 144 to the release chamber 135 between the sleeve 125 and the reaction force piston 92 fixed to the backup piston 88. A variable throttle mechanism 154 is provided for restricting the flow of the brake fluid from the through hole 144 to the release chamber 135 when the reaction force piston 92 is operated in response to the operation of the brake pedal 11 although the fluid is circulated.

  Therefore, when the high pressure in the boost hydraulic pressure control chamber 130 is released to the release chamber 135 as the pressure reducing valve 117 is opened, the flow of brake fluid from the through hole 144 provided in the reaction force piston 92 to the release chamber 135 is restricted. Therefore, it is possible to gently release the high hydraulic pressure to the release chamber 135 side and suppress the generation of operating noise.

  The sleeve 125 is disposed with its rear end facing the release chamber 135, and the through hole 144 is provided with a shaft hole 144a provided in the reaction force piston 92 so as to pass the front end through the pressure reducing valve hole 145; The variable throttle mechanism 154 is composed of a rear end portion of the sleeve 125 and the horizontal hole portion 144b. The variable throttle mechanism 154 includes a horizontal hole portion 144b that is continuous with the shaft hole portion 144a and opens to the outer surface of the reaction force piston 92. The aperture mechanism 154 can be configured very simply.

  In addition, a tapered diameter-expanded portion 125a that increases in diameter toward the rear is formed on the inner periphery of the rear end portion of the sleeve 125, so that the throttle amount is changed according to the operation of the reaction force piston 92. An appropriate aperture can be obtained.

  The control piston 90 is formed in a bottomed cylindrical shape with the front end as a closed end, and is connected to the brake pedal 11 via the input rod 170 and is accommodated in the control piston 90 so as to be slidable in the axial direction. An input piston 166 whose retreat limit is restricted by a retaining ring 169 that is detachably attached to the end, an elastic body 167 and a coil spring 168 that are connected in series and interposed between the input piston 166 and the control piston 90 Is stored in the control piston 90 while opening the inside of the control piston 90 to the atmosphere.

  That is, the stroke simulator 14 is accommodated in the control piston 90 provided in the hydraulic booster 13, and the overall length in the axial direction of the hydraulic booster 13 and the stroke simulator 14 is suppressed, and malfunction of the stroke simulator 14 occurs. However, it is possible to input a brake operation force from the brake pedal 11 to the control piston 90 via the stroke simulator 14. In addition, the stroke simulator 14 is configured to obtain a feeling of operation stroke of the brake pedal 11 with the spring force exerted by the elastic body 167 and the coil spring 168 without using hydraulic fluid, and can be assembled to the control piston 90. Easy.

  Incidentally, the brake operation force acting on the input piston 166 from the brake pedal 11 is transmitted to the control piston 90 via the elastic body 167 and the coil spring 168 connected in series via the intermediate transmission member 171. The spring constant of the coil spring 168 is set smaller than the spring constant of the elastic body 167. Therefore, as shown in FIG. 8, since the brake pedal 11 is depressed against the spring force exerted by the coil spring 168 in a region where the brake operation load is small, the change in the operation load with respect to the change in the operation stroke amount of the brake pedal 11 is gradual. Then, when the brake operation load increases, the brake pedal 1 is depressed against the spring force exerted by the elastic body 167, so that the change in the operation load with respect to the change in the operation stroke amount of the brake pedal 11 changes relatively greatly. Become.

  In addition, the elastic body 167 is cylindrical so as to be elastically contacted with the inner periphery of the control piston 90 by flexing so as to expand its diameter in accordance with the action of the axial compression force accompanying the forward movement of the input piston 166. Therefore, when the brake pedal 11 is depressed, it is necessary to operate the brake pedal 11 with an operation force that overcomes the elastic force of the elastic body 167 and the frictional force generated between the elastic body 167 and the control piston 90. On the other hand, when the brake operation force is loosened, the frictional force acts on the brake pedal 11 in the direction opposite to the return direction while the elastic body 167 is in sliding contact with the inner periphery of the control piston 90. The hysteresis width in relation to the brake operation stroke and the operation load in the stroke simulator 14 can be increased as shown in FIG. It is possible to reduce the operation load.

  Further, since the load from the coil spring 168 is applied to the elastic body 167 in advance, even if a sag occurs in the elastic body 167, the sag is absorbed by the coil spring 168 so that the normal brake is applied. The invalid stroke feeling at the time is eliminated, and a two-step operation simulation characteristic by the coil spring 168 and the elastic body 167 can be obtained regardless of the sag of the elastic body 167.

  FIG. 9 shows a second embodiment of the present invention. The stroke simulator 14 ′ includes an input piston 166 that is accommodated in the control piston 90 so as to be axially slidable, and the input piston 166 and the control piston 90. It has an elastic body 167 ′ and a coil spring 168 as elastic members interposed in series, and is accommodated in the control piston 90 while opening the control piston 90 to the atmosphere.

  The elastic body 167 ′ is formed in a cylindrical shape by an elastic material such as rubber. The elastic body 167 ′ and the metal coil spring 168 having a spring load smaller than that of the elastic body 167 ′ are: An intermediate transmission member 171 is interposed between the input piston 166 and the control piston 90 in series.

  Moreover, the elastic body 167 ′ has a tapered outer periphery with one end in the axial direction as a large diameter end, and is bent so as to increase in diameter according to the action of the compressive force accompanying the forward movement of the input piston 166, thereby controlling the piston. It is formed in a cylindrical shape so as to elastically contact the inner periphery of 90.

  According to the second embodiment, in addition to the effects of the first embodiment, the amount of change in the sliding contact area of the elastic body 167 'with the control piston 90 according to the operation stroke of the brake pedal 11 can be adjusted. The hysteresis width can be adjusted.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

  For example, in the above embodiment, the vehicle brake device including the tandem master cylinder M has been described. However, the present invention is applied to a vehicle brake device including a master cylinder in which a single master piston is slidably accommodated in a casing. It is also possible to do.

1 is a brake hydraulic pressure system diagram showing an overall configuration of a vehicle brake device. It is a longitudinal cross-sectional view of a master cylinder, a hydraulic pressure booster, and a stroke simulator. It is an expansion longitudinal cross-sectional view of a master cylinder. It is an expansion longitudinal cross-sectional view of a hydraulic booster. It is a principal part enlarged view of FIG. It is an enlarged vertical sectional view of a stroke simulator. It is a reaction force characteristic diagram. It is an action characteristic figure of a stroke simulator. It is an expansion longitudinal cross-sectional view of the stroke simulator of 2nd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Brake pedal 12 as brake operation member ... Fluid pressure generating source 15 ... Casing 25 ... Boosting fluid pressure chamber 26 ... Master piston 40 ... Reservoir 88 ... Backup piston 90 ... Control piston 92 ... Reaction force piston 116 ... Booster valve 117 ... Pressure reducing valve 118 ... Valve housing 121 ... Step part 122 ... Holding member 130 ... Booster fluid Pressure control chamber 145 ... Pressure reducing valve hole 146 ... Pressure reducing valve seat 147 ... Pressure reducing valve body 161 ... Pressure increasing valve seat 162 ... Pressure increasing valve body 163 ... Pressure increasing valve Hole 164 ... Hydraulic chamber 165 ... Communication hole 166 ... Input pistons 167 and 167 'as input members Elastic bodies 168 as elastic members Coil springs M as elastic members・ Master cylinder

Claims (2)

  A master cylinder (M) in which a master piston (26) facing the back surface of the boost hydraulic chamber (25) is slidably accommodated in the casing (15), and a brake operation input from the brake operation member (11) And a control piston (90) acting in the forward direction and a reaction force based on the hydraulic pressure in the boosted hydraulic pressure chamber (25) on the control piston (90) in the backward direction. ) And a booster hydraulic pressure chamber (92) that opens when the control piston (90) moves forward and closes when the control piston (90) moves backward. And a booster valve (116) interposed between the boost hydraulic pressure control chamber (130) and the hydraulic pressure generation source (12) connected to 25), and closes when the control piston (90) advances. Control piston (90 In the vehicular brake device, which includes a pressure reducing valve (117) interposed between the boost hydraulic pressure control chamber (130) and the reservoir (40) so as to be opened when the vehicle moves backward, the boost hydraulic pressure chamber The backup piston (88), whose front limit is restricted while facing the front face (25), when the hydraulic pressure in the boost hydraulic pressure chamber (25) decreases, the master piston ( 26) and the elastic member (167, 167 '; 168) between the input member (166) which is slidably accommodated in the casing (15) and is connected to the brake operating member (11). The booster hydraulic pressure control chamber formed in the backup piston (88) is fitted in the backup piston (88) so that the control piston (90) interposing the valve is slidable relative to the backup piston (88). The control piston (90) is coaxially connected to the rear end of the reaction force piston (92) with the front end facing the front end (130), and a valve housing is provided in front of the reaction force piston (92) in the backup piston (88). (118) is fitted and fixed, and the pressure reducing valve (117) forms a pressure reducing valve hole (145) communicating with the reservoir (40) and is provided on the reaction force piston (92). 146) and a poppet type pressure reducing valve body (147) accommodated in the valve housing (118) while being spring-biased while restricting the backward limit, and the pressure increasing valve (116) A pressure increasing valve hole (163) communicating with the boost hydraulic pressure control chamber (130) is formed so as to allow the front end of the pressure reducing valve body (147) to be inserted and provided in the valve housing (118). Valve seat for pressure increase (161 ) And a poppet-type pressure-increasing valve body (which can be pushed forward by the front end of the pressure-reducing valve body (147) and housed in the valve housing (118) and spring-biased rearward) 162), and the pressure increasing valve body (162) receives the sealing area when the pressure increasing valve body (162) is seated on the pressure increasing valve seat (161) and the hydraulic pressure of the boosted hydraulic pressure chamber (25). A vehicular brake device, wherein the front end pressure receiving area of the valve body (162) is set to be substantially equal.   The valve housing (118) is sandwiched between a step portion (121) provided on the backup piston (88) facing forward and a pressing member (122) screwed into the backup piston (88). In this way, the backup piston (88) is fitted and fixed, and the pressing member (122) and the pressing member (122) and the pressing member (122) face the front end of the pressure-increasing valve body (162). The vehicle brake according to claim 1, further comprising a communication hole (165) for communicating a hydraulic pressure chamber (164) formed between the valve housings (118) with the boost hydraulic pressure chamber (25). apparatus.

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