WO2018020815A1 - Stroke simulator - Google Patents

Abstract

This stroke simulator comprises: a cylinder (33) into which hydraulic pressure from a master cylinder is introduced; a piston (126) which is moved within the cylinder (33) by the hydraulic pressure; a reaction force spring (227) which urges the piston (126) against the hydraulic pressure; and a retainer (226) which defines the length of the reaction force spring (227). The retainer (226) has a cylindrical member (233) and a pin member (232) that is movable relatively to the cylindrical member (233). The cylindrical member (233) has disposed thereon a reaction force spring (277) on the outer peripheral side thereof, and an elastic member (209) on the inner peripheral side thereof.

Description

Stroke simulator

The present invention relates to a stroke simulator that generates a reaction force in response to an operation of a brake pedal.
This application claims priority on July 26, 2016 based on Japanese Patent Application No. 2016-146407 filed in Japan, the contents of which are incorporated herein by reference.

There are stroke simulators that generate a reaction force against the operation of the brake pedal (see, for example, Patent Documents 1 and 2).

JP 2010-47039 A Japanese Patent No. 5126238

It is desired to obtain good reaction force characteristics in the stroke simulator.

Therefore, the present invention provides a stroke simulator capable of obtaining good reaction force characteristics.

According to the first aspect of the present invention, the stroke simulator transmits a hydraulic reaction force to a brake pedal by introducing hydraulic pressure from a master cylinder that supplies hydraulic pressure to a braking cylinder provided on a wheel. It is. The stroke simulator includes a cylinder into which hydraulic pressure from the master cylinder is introduced, a piston that moves within the cylinder by the hydraulic pressure, a reaction force spring that biases the piston against the hydraulic pressure, A retainer for defining the length of the reaction force spring, the retainer having a tubular member and a pin member movable relative to the tubular member, the tubular member having an outer periphery The reaction force spring is disposed on the side, and an elastic member is disposed on the inner peripheral side.

According to the stroke simulator described above, good reaction force characteristics can be obtained.

It is a schematic block diagram of the brake device containing the stroke simulator of 1st Embodiment. It is sectional drawing of the master cylinder unit containing the stroke simulator of 1st Embodiment. It is a fragmentary sectional view of the stroke simulator of a 1st embodiment. It is a front view which shows the buffer member of the stroke simulator of 1st Embodiment. It is a side view which shows the buffer member of the stroke simulator of 1st Embodiment. It is a fragmentary sectional view of the stroke simulator of a 2nd embodiment. It is sectional drawing of the cylindrical member and buffer member of the stroke simulator of 2nd Embodiment. It is a fragmentary sectional view of the stroke simulator of a 3rd embodiment. It is a front view which shows the buffer member of the stroke simulator of 3rd Embodiment. It is a sectional side view which shows the buffer member of the stroke simulator of 3rd Embodiment. It is a fragmentary sectional view of the stroke simulator of a 4th embodiment. It is a fragmentary sectional view of the stroke simulator of a 4th embodiment. It is a fragmentary sectional view of the stroke simulator of a 5th embodiment. It is a front view which shows the buffer member of the stroke simulator of 5th Embodiment. It is a side view which shows the buffer member of the stroke simulator of 5th Embodiment.

(First embodiment)
The first embodiment will be described below with reference to FIGS. FIG. 1 schematically shows a brake device 10. The brake device 10 is for a four-wheeled vehicle.
The brake device 10 includes a brake pedal 11, a master cylinder unit 12, a reservoir 13, a power module 14, a brake cylinder 15FR, a brake cylinder 15RL, a brake cylinder 15RR, and a brake cylinder 15FL. is doing.
The brake cylinder 15FR is a brake cylinder for the right front wheel provided on the right front wheel of the four wheels. The brake cylinder 15RL is a brake cylinder for the left rear wheel provided on the left rear wheel of the four wheels. The brake cylinder 15RR is a brake cylinder for the right rear wheel provided on the right rear wheel of the four wheels. The brake cylinder 15FL is a brake cylinder for the left front wheel provided on the left front wheel of the four wheels. The brake cylinders 15FR, 15RL, 15RR, and 15FL are hydraulic operation mechanisms such as a disc brake or a drum brake that brake the rotation of the wheels.

The master cylinder unit 12 has an input rod 21 and a stroke sensor 22. The input rod 21 is connected to the brake pedal 11 at the base end side and moves in the axial direction in accordance with the operation amount of the brake pedal 11. The stroke sensor 22 detects the amount of movement of the input rod 21. The power module 14 electrically sucks the brake fluid from the reservoir 13 and supplies it to the brake cylinders 15FR, 15RL, 15RR, 15FL.
At that time, the power module 14 controls the brake fluid pressures of the brake cylinders 15FR, 15RL, 15RR, and 15FL based on the detection result of the stroke sensor 22 and the like. That is, the brake device 10 is a brake-by-wire type brake device.

The master cylinder unit 12 includes a master cylinder 26 and a stroke simulator 27.
An input rod 21 is inserted into the master cylinder 26. The master cylinder 26 generates a brake fluid pressure corresponding to the operation amount of the brake pedal 11 input via the input rod 21. The master cylinder 26 can supply the generated hydraulic pressure to the brake cylinders 15FR, 15RL, 15RR, and 15FL via the power module 14. The master cylinder 26 communicates with a reservoir 13 that stores brake fluid, and exchanges brake fluid with the reservoir 13. The stroke simulator 27 receives the hydraulic pressure from the master cylinder 26 and transmits the hydraulic reaction force to the brake pedal 11. At that time, the stroke simulator 27 transmits to the brake pedal 11 a hydraulic reaction force corresponding to the stepping force that is the operating force of the brake pedal 11. The stroke simulator 27 is provided below the master cylinder 26 in the vertical direction, and is provided integrally with the master cylinder 26.

As shown in FIG. 2, the master cylinder unit 12 has a metal cylinder member 31 formed by processing from one material.
The cylinder member 31 is shared by the master cylinder 26 and the stroke simulator 27. The cylinder member 31 includes an MC cylinder 32 and an SS cylinder 33 (cylinder) formed in parallel and integrally. The MC cylinder 32 constitutes the master cylinder 26. The SS cylinder 33 constitutes a stroke simulator 27. That is, the master cylinder 26 and the stroke simulator 27 are provided on a cylinder member 31 that is integrally formed from one material.

A cylinder hole 40 is formed in the MC cylinder 32 of the master cylinder 26. As a result, the MC cylinder 32 has a cylinder bottom 41 and a cylinder wall 42. The cylinder bottom 41 is on the back side of the cylinder hole 40 and has a plate shape. The cylinder wall 42 is cylindrical. The cylinder wall 42 extends from the cylinder bottom 41 to the cylinder opening 43 on the opposite side of the cylinder bottom 41.

The primary piston 46 is disposed on the cylinder opening 43 side in the cylinder wall 42 so as to be movable in the axial direction. The primary piston 46 constitutes the master cylinder 26. The primary piston 46 is made of metal. A secondary piston 47 is disposed on the cylinder bottom 41 side of the primary piston 46 in the cylinder wall 42 so as to be movable in the axial direction. The secondary piston 47 constitutes the master cylinder 26. The secondary piston 47 is made of metal. Of the primary piston 46 and the secondary piston 47, the primary piston 46 is disposed closer to the input rod 21 side, that is, the brake pedal 11 side than the secondary piston 47.

The tip of the input rod 21 opposite to the brake pedal 11 is in contact with the primary piston 46. The primary piston 46 receives the depression force of the brake pedal 11 through the input rod 21 and moves in the MC cylinder 32 in accordance with the operation of the brake pedal 11. The above-described stroke sensor 22 is attached to the primary piston 46. The stroke sensor 22 detects the movement amount of the input rod 21 that moves together with the primary piston 46 by detecting the movement amount of the primary piston 46. That is, the stroke sensor 22 detects the operation amount of the brake pedal 11.

A lid-like stopper member 51 is screwed to the end of the cylinder wall 42 opposite to the cylinder bottom 41. The input rod 21 is inserted inside the stopper member 51. A flange member 52 is fixed to an intermediate portion of the input rod 21. The stopper member 51 abuts against the flange member 52 from the side opposite to the cylinder bottom 41 and restricts further movement of the input rod 21 in the direction opposite to the cylinder bottom 41. That is, the stopper member 51 defines the movement limit position in the direction opposite to the cylinder bottom 41 of the input rod 21.

A primary pressure chamber 56 is formed between the primary piston 46 and the secondary piston 47 in the MC cylinder 32. A spring unit 57 is provided between the primary piston 46 and the secondary piston 47.
The spring unit 57 defines an interval between the primary piston 46 and the secondary piston 47 when the spring unit 57 is in a non-braking state where there is no input from the brake pedal 11. The spring unit 57 has a retainer 58 and a primary piston spring 59.
The retainer 58 can be expanded and contracted within a predetermined range. The primary piston spring 59 is a coil spring. The primary piston spring 59 biases the retainer 58 in the extending direction. The retainer 58 restricts the extension of the primary piston spring 59 so that the maximum length does not exceed a predetermined length. The secondary piston 47 connected to the primary piston 46 via the spring unit 57 also moves in the MC cylinder 32 in accordance with the operation of the brake pedal 11.

A secondary pressure chamber 61 is formed between the secondary piston 47 and the cylinder bottom 41 in the MC cylinder 32. A spring unit 62 is provided between the secondary piston 47 and the cylinder bottom 41.
The spring unit 62 defines an interval between the secondary piston 47 and the cylinder bottom portion 41 when the brake unit 11 is in a non-braking state where there is no input from the brake pedal 11. The spring unit 62 includes a retainer 63 and a secondary piston spring 64.
The retainer 63 can be expanded and contracted within a predetermined range. The secondary piston spring 64 biases the retainer 63 in the extending direction. The secondary piston spring 64 is a coil spring. The retainer 63 restricts the extension of the secondary piston spring 64 so that the maximum length does not exceed a predetermined length.

Both the primary piston 46 and the secondary piston 47 have a plunger shape. Therefore, the master cylinder 26 is a so-called plunger type master cylinder. The master cylinder 26 is a tandem type master cylinder having two primary pistons 46 and secondary pistons 47.
The master cylinder 26 is not limited to the tandem type master cylinder. The master cylinder 26 may be, for example, a plunger type master cylinder such as a single type master cylinder having one piston disposed on the MC cylinder 32 or a master cylinder having three or more pistons.

The MC cylinder 32 is integrally formed with a mounting base 65 that protrudes upward in the vertical direction from the cylinder wall 42 of the master cylinder 26. An attachment hole 66 for attaching the connecting member 66a and an attachment hole 67 for attaching the connecting member 67a are formed in the mounting base 65.
A pipe communicating with the reservoir 13 shown in FIG. 1 is connected to the connecting members 66a and 67a. As shown in FIG. 2, the mounting hole 66 and the mounting hole 67 are formed such that the positions of the cylinder holes 40 in the circumferential direction coincide with each other, and the positions of the cylinder holes 40 in the axial direction are shifted from each other. .
The master cylinder unit 12 is disposed in the vehicle in such a posture that the axial direction of the MC cylinder 32 including the cylinder hole 40 of the master cylinder 26 is along the vehicle front-rear direction, and the cylinder bottom 41 faces the front of the vehicle.

A secondary discharge path 68 is formed in the cylinder wall 42 of the master cylinder 26 in the vicinity of the cylinder bottom 41. The secondary discharge path 68 extends upward from the cylinder hole 40 so that the center axis thereof is orthogonal to the center axis of the cylinder hole 40. Further, a primary discharge path 69 is formed on the cylinder wall portion 42 of the master cylinder 26 on the cylinder opening 43 side with respect to the secondary discharge path 68.
The primary discharge path 69 has a central axis parallel to a direction perpendicular to the central axis of the cylinder hole 40, and extends horizontally in a vehicle-mounted state. The secondary discharge path 68 and the primary discharge path 69 communicate with the power module 14 shown in FIG.
The secondary discharge path 68 and the primary discharge path 69 can communicate with the brake cylinders 15FR, 15RL, 15RR, and 15FL via the power module 14. The secondary discharge path 68 and the primary discharge path 69 can discharge the brake fluid in the secondary pressure chamber 61 and the primary pressure chamber 56 shown in FIG. 2 toward the braking cylinders 15FR, 15RL, 15RR, and 15FL shown in FIG. ing.

As shown in FIG. 2, a sliding inner diameter portion 70, a large diameter inner diameter portion 71, and a female screw portion 72 are formed on the inner peripheral portion of the cylinder wall portion 42 in order from the cylinder bottom 41 side. The inner diameter surface of the sliding inner diameter portion 70 is cylindrical. The large-diameter inner diameter portion 71 has a cylindrical surface shape whose inner diameter surface is larger than that of the sliding inner diameter portion 70. The female thread portion 72 has a larger diameter than the large diameter inner diameter portion 71. The sliding inner diameter portion 70 and the large diameter inner diameter portion 71 have the center axes of the inner diameter surfaces aligned with each other. This central axis is the central axis of the cylinder hole 40 and the cylinder wall 42.

The stroke sensor 22 fixed to the primary piston 46 is disposed in the large-diameter inner diameter portion 71. The stroke sensor 22 moves in the axial direction of the MC cylinder 32 within the large diameter inner diameter portion 71. The primary piston 46 and the secondary piston 47 are slidably fitted to the inner diameter surface of the sliding inner diameter portion 70. The primary piston 46 and the secondary piston 47 are guided by the inner diameter surface of the sliding inner diameter portion 70 and move in the axial direction of the MC cylinder 32.

In the sliding inner diameter portion 70, a plurality of, specifically, four circumferential grooves 73, circumferential grooves 74, circumferential grooves 75, and circumferential grooves 76 are formed in this order from the cylinder bottom 41 side. The circumferential grooves 73 to 76 are all annular and are recessed outward in the radial direction from the inner diameter surface of the sliding inner diameter portion 70.

The circumferential groove 73 is formed in the vicinity of the mounting hole 66 on the cylinder bottom 41 side of the mounting hole 66 and the mounting hole 67. An annular piston seal 81 is disposed in the circumferential groove 73 so as to be held in the circumferential groove 73.

An opening groove 82 is formed closer to the cylinder opening 43 than the circumferential groove 73 in the sliding inner diameter portion 70 of the MC cylinder 32. The opening groove 82 is recessed radially outward from the inner diameter surface of the sliding inner diameter portion 70 and is formed in an annular shape. The opening groove 82 opens a supply passage 83 extending from the mounting hole 66 on the cylinder bottom 41 side into the cylinder hole 40.
The supply passage 83 is linear. The supply passage 83 has one end opened in the mounting hole 66 and the other end opened in the opening groove 82. Here, the opening groove 82 and the secondary piston 47 overlap with each other in the axial direction, and a portion surrounded by them is a secondary supply chamber 84. The secondary supply chamber 84 is always in communication with the reservoir 13 via the supply passage 83. The secondary supply chamber 84 is formed in an annular shape. Part of the secondary supply chamber 84 is formed by the secondary piston 47.

An axial groove 85 is formed in the upper part on the cylinder bottom 41 side from the circumferential groove 73 of the sliding inner diameter part 70 of the MC cylinder 32. The axial groove 85 opens to the circumferential groove 73 and extends linearly from the circumferential groove 73 toward the cylinder bottom 41. The axial groove 85 is recessed radially outward from the inner diameter surface of the sliding inner diameter portion 70.
The secondary discharge path 68 is formed at a position between the cylinder bottom 41 and the circumferential groove 73 and in the vicinity of the cylinder bottom 41. The axial groove 85 communicates the secondary discharge path 68 and the circumferential groove 73 via a secondary pressure chamber 61 between the secondary piston 47 and the cylinder bottom 41. The secondary discharge path 68 is formed at the upper end position of the axial groove 85. The secondary discharge path 68 extends upward from the upper end position of the secondary pressure chamber 61.

The circumferential groove 74 is formed in the sliding inner diameter portion 70 of the MC cylinder 32 on the side opposite to the circumferential groove 73 of the opening groove 82, that is, on the cylinder opening 43 side. An annular partition seal 86 is disposed in the circumferential groove 74 so as to be held in the circumferential groove 74.

The circumferential groove 75 described above is formed in the sliding inner diameter portion 70 of the MC cylinder 32 in the vicinity of the mounting hole 67 on the cylinder opening 43 side. An annular piston seal 91 is disposed in the circumferential groove 75 so as to be held in the circumferential groove 75.

An opening groove 92 is formed on the cylinder opening 43 side of the circumferential groove 75 in the sliding inner diameter portion 70 of the MC cylinder 32. The opening groove 92 is recessed radially outward from the inner diameter surface of the sliding inner diameter portion 70 and is formed in an annular shape. The opening groove 92 opens a supply passage 93 extending from the mounting hole 67 on the cylinder opening 43 side into the cylinder hole 40.
The supply passage 93 is linear. The supply passage 93 has one end opened in the mounting hole 67 and the other end opened in the opening groove 92. Here, the opening groove 92 and the primary piston 46 overlap with each other in the axial direction, and a portion surrounded by them is a primary supply chamber 94. The primary supply chamber 94 is always in communication with the reservoir 13 through the supply passage 93 and is formed in an annular shape. A part of the primary supply chamber 94 is formed by the primary piston 46.

An axial groove 95 is formed in an upper portion of the sliding inner diameter portion 70 of the MC cylinder 32 on the cylinder bottom 41 side than the circumferential groove 75. The axial groove 95 opens to the circumferential groove 75 and extends linearly from the circumferential groove 75 toward the cylinder bottom 41. The axial groove 95 is recessed radially outward from the inner diameter surface of the sliding inner diameter portion 70.
The primary discharge path 69 is formed at a position near the circumferential groove 74 of the axial groove 95. The axial groove 95 communicates the primary discharge passage 69 and the circumferential groove 75 via a primary pressure chamber 56 between the primary piston 46 and the secondary piston 47. The primary discharge path 69 is formed at the upper end position of the axial groove 95. The primary discharge path 69 extends laterally from the upper end position of the primary pressure chamber 56.

The circumferential groove 76 is formed in the sliding inner diameter portion 70 of the MC cylinder 32 on the side opposite to the circumferential groove 75 of the opening groove 92, that is, on the cylinder opening 43. An annular partition seal 96 is disposed in the circumferential groove 76 so as to be held in the circumferential groove 76.

The secondary piston 47 has a cylindrical portion 101 and a bottom portion 102 formed at an intermediate position in the axial direction of the cylindrical portion 101. The secondary piston 47 has a plunger shape. The cylindrical portion 101 of the secondary piston 47 is fitted to each of the sliding inner diameter portion 70 of the MC cylinder 32 and the piston seal 81 and the partition seal 86 provided on the sliding inner diameter portion 70. The secondary piston 47 is guided by these and slides in the MC cylinder 32.

A plurality of ports 103 are formed at the end of the cylindrical portion 101 on the cylinder bottom 41 side. The plurality of ports 103 penetrates the cylindrical portion 101 in the radial direction. The plurality of ports 103 are radially formed at equal intervals in the circumferential direction of the cylindrical portion 101. A spring unit 62 is inserted into the secondary piston 47 on the cylinder bottom 41 side of the cylindrical portion 101.
In the spring unit 62, one end of the retainer 63 in the axial direction comes into contact with the bottom 102 of the secondary piston 47, and the other end in the axial direction of the retainer 63 comes into contact with the cylinder bottom 41 of the MC cylinder 32. The secondary piston spring 64 determines the distance between the secondary piston 47 and the cylinder bottom 41 in a non-braking state where there is no input from the input rod 21. The secondary piston spring 64 contracts when there is an input from the input rod 21 and biases the secondary piston 47 toward the cylinder opening 43 with a force corresponding to the length of the contraction.

The portion surrounded by the cylinder bottom 41 side of the cylinder bottom 41 and the cylinder wall 42 and the secondary piston 47 is the secondary pressure chamber 61 described above. The secondary pressure chamber 61 generates a brake fluid pressure according to the operation amount of the brake pedal 11 and supplies the brake fluid pressure to the secondary discharge path 68. In other words, the master cylinder 26 generates hydraulic pressure in the secondary pressure chamber 61 in the MC cylinder 32 according to the operation amount of the brake pedal 11.
The secondary pressure chamber 61 communicates with the secondary supply chamber 84, that is, the reservoir 13 when the secondary piston 47 is in a position to open the port 103 into the opening groove 82.
The secondary piston 47 opens the port 103 into the opening groove 82 when the brake pedal 11 is not operated. In other words, the secondary supply chamber 84 provided in the master cylinder 26 is always connected to the reservoir 13 and communicates with the secondary pressure chamber 61 when the brake pedal 11 is not operated. The reservoir 13 stores the brake fluid supplied to the secondary pressure chamber 61 in this way.

The partition seal 86 held in the circumferential groove 74 of the MC cylinder 32 is an integrally molded product made of synthetic rubber. The partition seal 86 is a cup seal having a C-shaped one-sided section in a plane including the center line. The partition seal 86 is disposed in the circumferential groove 74 with the lip portion facing the cylinder opening 43 side. The partition seal 86 has an inner periphery that is in sliding contact with the outer peripheral surface of the secondary piston 47 and an outer periphery that is in contact with the peripheral groove 74 of the MC cylinder 32. Thereby, the partition seal 86 always seals the gap at the position of the secondary piston 47 and the partition seal 86 of the MC cylinder 32.

The piston seal 81 held in the circumferential groove 73 of the MC cylinder 32 is an integrally molded product made of synthetic rubber such as EPDM. The piston seal 81 is a cup seal whose one-side shape in cross section on the surface including the center line is E-shaped. The piston seal 81 is disposed in the circumferential groove 73 with the lip portion facing the cylinder bottom 41 side. The piston seal 81 is in sliding contact with the outer peripheral surface of the secondary piston 47 and the outer periphery is in contact with the peripheral groove 73 of the MC cylinder 32. As a result, the piston seal 81 can seal the gap between the secondary piston 47 and the piston seal 81 of the MC cylinder 32.

The secondary piston 47 is in a non-braking position that opens the port 103 into the opening groove 82 when there is no input from the input rod 21.
As shown in FIG. 2, the piston seal 81 partially overlaps the port 103 in the axial direction when the secondary piston 47 is in the non-braking position. In this state, the secondary pressure chamber 61 and the reservoir 13 communicate with each other via the secondary supply chamber 84 and the port 103.

By the input from the input rod 21, the primary piston 46 moves toward the cylinder bottom 41 along the axial direction. Then, the primary piston 46 is pressed via the spring unit 57 and the secondary piston 47 moves toward the cylinder bottom 41 along the axial direction.
That is, the primary piston 46 moves directly in the MC cylinder 32 in accordance with the depression force of the brake pedal 11 shown in FIG. The secondary piston 47 also moves directly in the MC cylinder 32 according to the depression force of the brake pedal 11.

At that time, the secondary piston 47 slides on the inner diameter of the sliding inner diameter portion 70 of the MC cylinder 32 and the inner periphery of the piston seal 81 and the partition seal 86 held by the MC cylinder 32.
When moved to the cylinder bottom 41 side, the secondary piston 47 is in a state where the port 103 is positioned closer to the cylinder bottom 41 than the piston seal 81. In this state, the piston seal 81 is in a state of sealing between the reservoir 13 and the secondary supply chamber 84 and the secondary pressure chamber 61. As a result, when the secondary piston 47 further moves to the cylinder bottom 41 side, the brake fluid in the secondary pressure chamber 61 is pressurized. The brake fluid pressurized in the secondary pressure chamber 61 is discharged from the secondary discharge path 68.

When the input from the input rod 21 is reduced from the state in which the brake fluid in the secondary pressure chamber 61 is pressurized, the secondary piston 47 attempts to return to the cylinder opening 43 side by the biasing force of the secondary piston spring 64 of the spring unit 62. To do. The movement of the secondary piston 47 increases the volume of the secondary pressure chamber 61.
At that time, the return of the brake fluid to the secondary pressure chamber 61 via the secondary discharge path 68 may not catch up with the volume expansion of the secondary pressure chamber 61. Then, after the hydraulic pressure in the secondary supply chamber 84, which is atmospheric pressure, and the hydraulic pressure in the secondary pressure chamber 61 become equal, the hydraulic pressure in the secondary pressure chamber 61 becomes negative.

Then, the negative pressure in the secondary pressure chamber 61 deforms the piston seal 81 to form a gap between the piston seal 81 and the circumferential groove 73. As a result, the brake fluid in the secondary supply chamber 84 is supplied to the secondary pressure chamber 61 through this gap. Thereby, the speed | rate which returns the hydraulic pressure of the secondary pressure chamber 61 from a negative pressure state to atmospheric pressure is accelerated. That is, the piston seal 81 is a check valve that allows the brake fluid in the secondary supply chamber 84 to flow into the secondary pressure chamber 61 and restricts the flow of brake fluid in the opposite direction.

The primary piston 46 has a cylindrical portion 106 and a bottom portion 107 formed at an intermediate position in the axial direction of the cylindrical portion 106. The primary piston 46 has a plunger shape. The primary piston 46 is fitted to each of the sliding inner diameter portion 70 of the MC cylinder 32, the piston seal 91 provided on the sliding inner diameter portion 70, and the partition seal 96. The primary piston 46 is guided by these and slides in the MC cylinder 32. The input rod 21 is inserted inside the cylindrical portion 106 and is in contact with the bottom portion 107. The bottom 107 is pressed by the input rod 21 and the primary piston 46 moves forward to the cylinder bottom 41 side.

A plurality of ports 108 are formed on the secondary piston 47 side of the cylindrical portion 106. The plurality of ports 108 penetrate the cylindrical portion 106 in the radial direction. The plurality of ports 108 are formed radially at equal intervals in the circumferential direction of the cylindrical portion 106. The above-described spring unit 57 is provided on the secondary piston 47 side of the primary piston 46.
The spring unit 57 defines an interval between the primary piston 46 and the secondary piston 47 in a non-braking state where there is no input from the input rod 21. In the spring unit 57, the retainer 58 comes into contact with the bottom 102 of the secondary piston 47 and the bottom 107 of the primary piston 46. The primary piston spring 59 contracts when there is an input from the input rod 21 and the interval between the primary piston 46 and the secondary piston 47 is narrowed. The primary piston spring 59 biases the primary piston 46 toward the input rod 21 with a force corresponding to the length of the contraction.

Here, a portion formed by being surrounded by the cylinder wall portion 42 of the MC cylinder 32, the primary piston 46 and the secondary piston 47 is the primary pressure chamber 56 described above. The primary pressure chamber 56 generates a brake fluid pressure according to the operation amount of the brake pedal 11 and supplies the brake fluid to the primary discharge passage 69.
In other words, the master cylinder 26 generates hydraulic pressure in the primary pressure chamber 56 in the MC cylinder 32 according to the operation amount of the brake pedal 11. In other words, the primary piston 46 forms a primary pressure chamber 56 that supplies hydraulic pressure to the primary discharge passage 69 between the secondary piston 47 and the MC cylinder 32. The primary pressure chamber 56 communicates with the primary replenishing chamber 94, that is, the reservoir 13 when the primary piston 46 is in a position for opening the port 108 into the opening groove 92 as shown in FIG. 2. The primary piston 46 opens the port 108 into the opening groove 92 when the brake pedal 11 is not operated. In other words, the primary supply chamber 94 provided in the master cylinder 26 is always connected to the reservoir 13 and communicates with the primary pressure chamber 56 when the brake pedal 11 is not operated. The reservoir 13 stores the brake fluid supplied to the primary pressure chamber 56 in this way.

The partition seal 96 held in the circumferential groove 76 of the MC cylinder 32 is a common part with the partition seal 86. The partition seal 96 is an integrally molded product made of synthetic rubber. The partition seal 96 is a cup seal having a C-shaped one-sided section in a plane including the center line. The partition seal 96 is disposed in the circumferential groove 76 with the lip portion facing the cylinder bottom 41 side. The partition seal 96 is in sliding contact with the outer peripheral surface of the moving primary piston 46, and the outer periphery is in contact with the peripheral groove 76 of the MC cylinder 32. Thereby, the division seal 96 always seals the gap at the position of the division seal 96 of the primary piston 46 and the MC cylinder 32.

The piston seal 91 held in the circumferential groove 75 of the MC cylinder 32 is a common part with the piston seal 81. The piston seal 91 is an integrally molded product made of synthetic rubber such as EPDM. The piston seal 91 is a cup seal whose one-side shape in cross section on the surface including the center line is E-shaped. The piston seal 91 is disposed in the circumferential groove 75 with the lip portion facing the cylinder bottom 41 side. The piston seal 91 is in sliding contact with the outer peripheral surface of the primary piston 46, and the outer periphery is in contact with the peripheral groove 75 of the MC cylinder 32. As a result, the piston seal 91 can seal the gap between the primary piston 46 and the piston seal 91 of the MC cylinder 32.

The primary piston 46 is in a non-braking position that opens the port 108 into the opening groove 92 when there is no input from the input rod 21. The piston seal 91 is configured to partially overlap the port 108 of the primary piston 46 in the axial direction when the primary piston 46 is in the non-braking position. In this state, the primary pressure chamber 56 and the reservoir 13 communicate with each other via the primary supply chamber 94 and the port 108.

The primary piston 46 moves to the cylinder bottom 41 side along the axial direction by the input from the input rod 21. At that time, the primary piston 46 slides on the inner circumference of the sliding inner diameter portion 70 of the MC cylinder 32 and the piston seal 91 and the partition seal 96 held by the MC cylinder 32. When moved to the cylinder bottom 41 side, the primary piston 46 is in a state where the port 108 is positioned closer to the cylinder bottom 41 than the piston seal 91. In this state, the piston seal 91 is in a state of sealing between the reservoir 13 and the primary supply chamber 94 and the primary pressure chamber 56. Thereby, when the primary piston 46 further moves to the cylinder bottom 41 side, the brake fluid in the primary pressure chamber 56 is pressurized. The brake fluid pressurized in the primary pressure chamber 56 is discharged from the primary discharge path 69.

When the input from the input rod 21 is reduced from the state in which the brake fluid in the primary pressure chamber 56 is pressurized, the primary piston 46 is opposite to the cylinder bottom 41 by the biasing force of the primary piston spring 59 of the spring unit 57. Trying to return.
The movement of the primary piston 46 increases the volume of the primary pressure chamber 56. At that time, the return of the brake fluid through the primary discharge path 69 may not be able to catch up with the volume expansion of the primary pressure chamber 56. Then, after the hydraulic pressure in the primary replenishing chamber 94, which is atmospheric pressure, becomes equal to the hydraulic pressure in the primary pressure chamber 56, the hydraulic pressure in the primary pressure chamber 56 becomes negative.

Then, the negative pressure in the primary pressure chamber 56 deforms the piston seal 91 to form a gap between the piston seal 91 and the circumferential groove 75. As a result, the brake fluid in the primary supply chamber 94 is supplied to the primary pressure chamber 56 through this gap. As a result, the speed at which the hydraulic pressure in the primary pressure chamber 56 is returned from the negative pressure state to the atmospheric pressure is increased. That is, the piston seal 91 is a check valve that allows the brake fluid in the primary supply chamber 94 to flow into the primary pressure chamber 56 and restricts the flow of brake fluid in the opposite direction.

A cylinder hole 120 parallel to the cylinder hole 40 of the MC cylinder 32 is formed in the SS cylinder 33 of the stroke simulator 27. Therefore, the SS cylinder 33 has a cylinder bottom 121 and a cylinder wall 122. The cylinder bottom 121 is on the back side of the cylinder hole 120.
The cylinder wall 122 is cylindrical. The cylinder wall 122 extends from the cylinder bottom 121 to the cylinder opening 123 on the opposite side of the cylinder bottom 121. The cylinder hole 40 and the cylinder hole 120 are formed from the same plane side surface of the cylinder member 31, and the horizontal positions of the center axes of the cylinder member 31 are overlapped. In other words, the center axis of the cylinder hole 120 is arranged in parallel vertically below the center axis of the cylinder hole 40.
The cylinder opening 123 of the SS cylinder 33 is aligned with the cylinder opening 43 of the MC cylinder 32 in the axial direction. The cylinder bottom 121 of the SS cylinder 33 is shifted in the axial direction toward the cylinder openings 43 and 123 from the cylinder bottom 41 of the MC cylinder 32.

The SS piston 126 (piston) is movably disposed on the cylinder bottom 121 side in the cylinder wall 122. The SS piston 126 constitutes a stroke simulator 27. The SS piston 126 is made of metal. Further, a reaction force generation mechanism 127 is provided on the cylinder opening 123 side of the SS piston 126 in the cylinder wall 122. The reaction force generation mechanism 127 biases the SS piston 126 toward the cylinder bottom 121.

A sliding inner diameter portion 130, an intermediate inner diameter portion 131, a large diameter inner diameter portion 132, and a female thread portion 133 are formed in order from the cylinder bottom 121 side on the inner peripheral portion of the cylinder wall portion 122. The inner diameter surface of the sliding inner diameter portion 130 is cylindrical. The intermediate inner diameter portion 131 has a cylindrical surface shape whose inner diameter surface is larger than the sliding inner diameter portion 130. The large-diameter inner diameter portion 132 has a cylindrical surface shape whose inner diameter surface is larger than the intermediate inner diameter portion 131. The sliding inner diameter portion 130, the intermediate inner diameter portion 131, and the large diameter inner diameter portion 132 are aligned with the central axis of each inner diameter surface. This central axis is the central axis of the cylinder hole 120 and the cylinder wall 122.

In the sliding inner diameter portion 130, a plurality of, specifically, two circumferential grooves 136 and circumferential grooves 137 are formed in this order from the cylinder bottom 121 side. The circumferential grooves 136 and 137 are all formed in an annular shape and are recessed radially outward from the inner diameter surface of the sliding inner diameter portion 130.

A bending-shaped introduction passage 141 is formed in the cylinder bottom 121. The introduction passage 141 has a first passage hole 138 and a second passage hole 139. The first passage hole 138 is linear. The first passage hole 138 extends from the cylinder hole 120 in the direction opposite to the cylinder opening 123.
The second passage hole 139 is linear. The second passage hole 139 extends vertically downward from the vicinity of the cylinder bottom 41 of the cylinder hole 40 and communicates with the end of the first passage hole 138 opposite to the cylinder hole 120. Therefore, the introduction passage 141 communicates the cylinder hole 40 and the cylinder hole 120. Fluid pressure is introduced into the SS cylinder 33 from the secondary pressure chamber 61 of the master cylinder 26 via the introduction passage 141.

The central axis of the first passage hole 138 is parallel to the central axis of the cylinder hole 40. The center axis of the second passage hole 139 is orthogonal to the center axis of the cylinder hole 40 and is orthogonal to the center axis of the cylinder hole 120. The second passage hole 139 is formed on the same straight line as the secondary discharge passage 68 of the master cylinder 26 and has the same diameter as the secondary discharge passage 68. Therefore, the secondary discharge path 68 and the second passage hole 139 are formed by a single drilling process using a single drill. The circumferential groove 136 is formed closer to the cylinder opening 123 than the introduction passage 141.

Bleeder passages 142 and 143 are formed in the cylinder wall 122. The bleeder passage 142 opens at the upper end of the intermediate inner diameter portion 131 on the sliding inner diameter portion 130 side. The bleeder passage 142 extends to the outer surface position of the cylinder member 31. A bleeder plug (not shown) for opening and closing the bleeder passage 142 is disposed in this portion of the bleeder passage 142. The bleeder plug opens the bleeder passage 142 to the outside air in the open state, and blocks the bleeder passage 142 from the outside air in the closed state.

The bleeder passage 143 opens at the upper end of the sliding inner diameter portion 130 on the cylinder bottom 121 side. The bleeder passage 143 extends to the outer surface position of the cylinder member 31. A bleeder plug (not shown) for opening and closing the bleeder passage 143 is disposed in this portion of the bleeder passage 143. The bleeder plug opens the bleeder passage 143 to the outside air in the open state, and blocks the bleeder passage 143 from the outside air in the closed state.

An annular partition seal 151 is disposed in the circumferential groove 136 that is an annular groove so as to be held in the circumferential groove 136. The partition seal 151 also constitutes the stroke simulator 27. The partition seal 151 is provided on the SS cylinder 33 side of the SS cylinder 33 and the SS piston 126.

An axial groove 152 is formed in the upper part on the cylinder bottom 121 side with respect to the circumferential groove 136 of the sliding inner diameter part 130 of the SS cylinder 33. The axial groove 152 opens to the circumferential groove 136 and extends linearly from the circumferential groove 136 toward the cylinder bottom 121. The axial groove 152 is recessed outward in the radial direction from the inner diameter surface of the sliding inner diameter portion 130. A bleeder passage 143 is opened at the upper end of the axial groove 152 on the cylinder bottom 121 side.

The above-mentioned circumferential groove 137 is formed in the sliding inner diameter portion 130 of the SS cylinder 33 in the vicinity of the end portion on the cylinder opening 123 side. An annular partition seal 161 is disposed in the circumferential groove 137 that is an annular groove so as to be held in the circumferential groove 137. The partition seal 161 also constitutes the stroke simulator 27. The partition seal 161 is provided on the SS cylinder 33 side of the SS cylinder 33 and the SS piston 126.

An axial groove 165 is formed above the circumferential groove 137 of the sliding inner diameter portion 130 of the SS cylinder 33 on the cylinder opening 123 side. The axial groove 165 has one end opened in the circumferential groove 137 and linearly extends from the circumferential groove 137 toward the cylinder opening 123. The axial groove 165 is recessed outward in the radial direction from the inner diameter surface of the sliding inner diameter portion 130.

Although not shown, the axial grooves 152 and 165 have a cross-sectional shape in a plane orthogonal to the central axis of the sliding inner diameter portion 130 having an arc shape smaller in diameter than the inner diameter surface of the sliding inner diameter portion 130. ing.
The axial grooves 152 and 165 are eccentric grooves in which the center of the arc is offset with respect to the center of the inner diameter surface of the sliding inner diameter portion 130. Although not shown, the axial grooves 85 and 95 of the master cylinder 26 also have a cross-sectional shape that is smaller than the inner diameter surface of the sliding inner diameter portion 70 in a plane orthogonal to the central axis of the sliding inner diameter portion 70. It is an eccentric groove having an arc shape.

The SS piston 126 has a cylindrical portion 171, a bottom portion 172 formed at an intermediate position in the axial direction of the cylindrical portion 171, and a protruding portion 173 protruding in the axial direction from the bottom portion 172. Therefore, the SS piston 126 has a plunger shape. The SS piston 126 has a cylindrical portion 171 fitted to each of the sliding inner diameter portion 130 of the SS cylinder 33 and the partition seals 151 and 161 provided on the sliding inner diameter portion 130. The SS piston 126 is guided by these and slides in the SS cylinder 33. At that time, each of the partition seals 151 and 161 seals between the inner periphery of the SS cylinder 33 and the outer periphery of the SS piston 126 in an annular shape. In the SS piston 126, the bottom 172 is disposed closer to the cylinder opening 123 than the center of the cylindrical portion 171 in the axial direction. The protruding portion 173 protrudes from the bottom portion 172 to the cylinder opening 123 side.

A small-diameter outer diameter portion 176 having an outer diameter smaller than that of the other main outer-diameter portion 175 is formed at the end of the cylindrical portion 171 on the cylinder bottom 121 side. A plurality of ports 174 are formed in the cylindrical portion 171 at the position of the small diameter outer diameter portion 176. The plurality of ports 174 penetrates the cylindrical portion 171 in the radial direction. The plurality of ports 174 are formed so as to be radial at equal intervals in the circumferential direction of the cylindrical portion 171.
As shown in FIG. 2, when the SS piston 126 is in contact with the cylinder bottom 121, the small diameter outer diameter portion 176 overlaps the axial groove 152 and the axial position. In this state, the SS piston 126 makes the port 174 communicate with the axial groove 152. In this state, the first passage hole 138 of the introduction passage 141 opens to the inside in the radial direction of the cylindrical portion 171.

Here, a portion surrounded by the cylinder bottom 121, the cylinder bottom 121 side of the cylinder wall 122 and the SS piston 126 is an SS pressure chamber 181.
The SS pressure chamber 181 is always in communication with the secondary pressure chamber 61 of the master cylinder 26 via the introduction passage 141. The SS pressure chamber 181 also constitutes the stroke simulator 27. The SS pressure chamber 181 communicates with the secondary pressure chamber 61 of the master cylinder 26 on one end side of the SS piston 126 in the SS cylinder 33. The SS pressure chamber 181 moves the SS piston 126 in the SS cylinder 33 by the hydraulic pressure introduced from the secondary pressure chamber 61. In other words, the SS piston 126 moves in the SS cylinder 33 by the hydraulic pressure introduced from the secondary pressure chamber 61.
On the other hand, the reaction force generating mechanism 127 biases the SS piston 126 against the hydraulic pressure introduced into the SS pressure chamber 181 on the other end side of the SS piston 126 in the SS cylinder 33.
The reaction force generating mechanism 127 is connected via the SS piston 126 to the brake fluid in the SS pressure chamber 181, the brake fluid in the secondary pressure chamber 61, the secondary piston 47 shown in FIG. 2, the brake fluid in the primary pressure chamber 56, the primary piston A reaction force corresponding to the depression force of the brake pedal 11 shown in FIG. 1 is applied to the brake pedal 11 via 46 and the input rod 21.

As shown in FIG. 2, the partition seal 151 held in the circumferential groove 136 of the SS cylinder 33 is an integrally molded product made of synthetic rubber. The partition seal 151 is a cup seal having a C-shaped one-sided cross section on the plane including the center line. The partition seal 151 is disposed in the circumferential groove 136 with the lip portion facing the cylinder bottom 121 side. The inner periphery of the partition seal 151 is in sliding contact with the outer peripheral surface of the SS piston 126, and the outer periphery is in contact with the peripheral groove 136 of the SS cylinder 33. Thereby, the partition seal 151 always seals the gap between the SS piston 126 and the position of the partition seal 151 of the SS cylinder 33.

The partition seal 161 held in the circumferential groove 137 of the SS cylinder 33 is an integrally molded product made of synthetic rubber. The partition seal 161 is a cup seal having a C-shaped one-sided section in a plane including the center line. The partition seal 161 is disposed in the circumferential groove 137 with the lip portion facing the cylinder opening 123 side. The partition seal 161 is in sliding contact with the outer peripheral surface of the SS piston 126 and the outer periphery is in contact with the peripheral groove 137 of the SS cylinder 33. As a result, the partition seal 161 always seals the gap between the SS piston 126 and the partition seal 161 of the SS cylinder 33.

The reaction force generation mechanism 127 includes a metal lid member 191, a rubber seal member 192, and a buffer member 193 that is a rubber elastic member. The lid member 191 is screwed into the female thread portion 133 while being fitted to the large-diameter inner diameter portion 132 of the SS cylinder 33. The seal member 192 is held by the lid member 191. The seal member 192 seals the gap between the lid member 191 and the large diameter inner diameter portion 132 of the SS cylinder 33. The buffer member 193 is attached to the lid member 191.

The lid member 191 has a substrate part 194, a fitting part 195, and a protruding part 196. The substrate part 194 has a disk shape. The fitting portion 195 has a cylindrical shape and protrudes from the outer peripheral edge portion of the substrate portion 194 in the axial direction.
The protruding portion 196 has an outer diameter smaller than that of the fitting portion 195, and protrudes from the board portion 194 to the same side as the fitting portion 195. On the outer peripheral side of the fitting portion 195, a male screw portion 197, a fitting outer diameter portion 198, and a circumferential groove 199 are formed.
The fitting portion 195 is fitted to the SS cylinder 33. At that time, the male screw portion 197 is screwed to the female screw portion 133, and the fitting outer diameter portion 198 is fitted to the large diameter inner diameter portion 132.
The circumferential groove 199 is recessed radially inward from the outer diameter surface of the fitting outer diameter portion 198 and has an annular shape. A seal member 192 that is an O-ring is disposed in the circumferential groove 199. The seal member 192 seals the gap between the lid member 191 and the SS cylinder 33. At the center in the radial direction of the substrate portion 194, an engagement recess 200 is formed on the side opposite to the fitting portion 195. The engagement recess 200 is recessed from the end surface of the base plate portion 194 opposite to the cylinder bottom 121 to the inside of the projection 196 in the axial direction. When the male threaded portion 197 is screwed into the female threaded portion 133 of the SS cylinder 33, a screwing tool such as a hexagon wrench is engaged with the engaging recess 200.

In the protruding portion 196, a concave portion 201 is formed on the protruding tip side at the center in the radial direction. The recessed part 201 is recessed from the front end surface of the protruding part 196 on the protruding front end side to the side opposite to the cylinder bottom part 121. A cylindrical buffer member 193 that is an elastic member is fitted and fixed in the recess 201. When the buffer member 193 is in contact with the bottom surface of the recess 201, the buffer member 193 protrudes further toward the cylinder bottom 121 than the front end surface of the protrusion 196.

The reaction force generation mechanism 127 includes a metal spring 206, a metal locking retainer 207, a metal spring unit 208, and a buffer member 209 (elastic member) made of a rubber elastic member. Yes. One end of the spring 206 is in contact with the substrate portion 194 of the lid member 191 in a state where the spring 206 is inserted inside the fitting portion 195 and the protruding portion 196 is inserted inside. The locking retainer 207 contacts the other end of the spring 206 and locks the other end. The spring unit 208 is interposed between the locking retainer 207 and the SS piston 126. The buffer member 209 is disposed in the spring unit 208.

Spring 206 is a coil spring. As shown in FIG. 3, the locking retainer 207 has a lid part 221, a body part 222, and a flange part 223. The lid portion 221 has a disk shape. The body portion 222 has a cylindrical shape and extends in the axial direction from the outer peripheral edge portion of the lid portion 221. The flange portion 223 extends outward in the radial direction from the end portion of the body portion 222 opposite to the lid portion 221 and is formed in an annular shape. In the retaining retainer 207, the flange portion 223 abuts against the end portion of the spring 206 in a state where the lid portion 221 and the body portion 222 are inserted into the spring 206, and latches them.

The spring unit 208 includes a retainer 226 (retainer) and a spring 227 (reaction force spring). The spring 227 is a coil spring. The retainer 226 can be expanded and contracted within a predetermined range. The retainer 226 holds the spring 227 in a contracted state.
Therefore, the spring 227 biases the retainer 226 in the extending direction. The retainer 226 restricts the length of the spring 227 in the contracted state so as not to exceed a predetermined length. That is, the retainer 226 defines the set length of the spring 227.

The retainer 226 includes a locking member 231, a pin member 232, and a tubular member 233. The locking member 231 has a disk shape. The pin member 232 is fixed to the center of the locking member 231 in the radial direction and extends from the locking member 231 in the axial direction. The pin member 232 includes an engaging portion 235, a shaft portion 236, and a flange portion 237 in order from one end side in the axial direction. The pin member 232 is attached to the locking member 231 at the engaging portion 235. The shaft portion 236 extends in the axial direction from the locking member 231 and is formed in a columnar shape. The flange portion 237 extends radially outward from the end portion of the shaft portion 236 opposite to the engagement portion 235 and is formed in an annular shape.

The cylindrical member 233 has a sliding part 240, an abutting part 241, a body part 242 and a flange part 243 in order from one end side in the axial direction. The sliding part 240 is cylindrical. The contact portion 241 extends from the one end edge of the sliding portion 240 in the axial direction outward in the radial direction from the sliding portion 240 and is formed in an annular shape.
The body portion 242 extends from the outer peripheral edge portion of the contact portion 241 to the side opposite to the sliding portion 240 and is formed in a cylindrical shape having an inner diameter larger than that of the sliding portion 240. The flange portion 243 extends radially outward from an end edge of the body portion 242 opposite to the contact portion 241 and is formed in an annular shape.

A plurality of through holes 244 that penetrates in the radial direction are formed in the body portion 242 in the vicinity of the contact portion 241. A plurality of concave portions 245 are formed in the body portion 242 at the end portion on the flange portion 243 side. The recessed portion 245 has a shape that is recessed radially outward from the inner peripheral surface 246 a of the main body portion 246 other than the recessed portion 245 of the body portion 242, and extends in the axial direction of the tubular member 233. The concave portions 245 are specifically formed at four locations on the inner peripheral side of the body portion 242, and are formed at equal division positions in the circumferential direction of the body portion 242.
A convex portion 247 that protrudes inward in the radial direction is formed between the adjacent concave portions 245. The convex portions 247 are formed in the same number as the concave portions 245. In the circumferential direction of the body portion 242, the width of the concave portion 245 is wider than the width of the convex portion 247.

The flange portion 237 of the pin member 232 is slidably disposed inside the trunk portion 242. The shaft portion 236 of the pin member 232 is slidably disposed inside the sliding portion 240. Therefore, the cylindrical member 233 slides in the axial direction on the shaft portion 236 of the pin member 232 in the sliding portion 240 and on the flange portion 237 of the pin member 232 in the body portion 242. As a result, the cylindrical member 233 can move relative to the pin member 232. In other words, the pin member 232 can move relative to the cylindrical member 233. In other words, the retainer 226 can be expanded and contracted.

When the pin member 232 moves in a direction to increase the extension amount of the shaft portion 236 from the cylindrical member 233, the flange portion 237 comes into contact with the contact portion 241, and further axial movement with respect to the cylindrical member 233 is performed. It becomes a regulated state.
As a result, the retainer 226 is restricted from extending further by the flange portion 237 of the pin member 232 coming into contact with the contact portion 241 of the cylindrical member 233 during extension.

In the retainer 226, the locking member 231 comes into contact with one end of the spring 227 and locks it. In the retainer 226, the flange portion 243 of the cylindrical member 233 comes into contact with the other end of the spring 227 and locks it. At that time, the body 242 extends from the flange 243 into the spring 227. In other words, the cylindrical member 233 has the spring 227 disposed on the outer peripheral side thereof.
The pin member 232 extends from the locking member 231 into the spring 227 and engages with the tubular member 233. The retainer 226 restricts further extension of the spring 227 in the contracted state by the flange portion 237 of the pin member 232 coming into contact with the contact portion 241 of the cylindrical member 233. The buffer member 209 is an elastic member, and is disposed in the body portion 242 of the cylindrical member 233. In other words, the buffer member 209 is disposed on the inner peripheral side of the cylindrical member 233.

In the spring unit 208, the locking member 231 is inserted into the locking retainer 207 and is in contact with the lid 221. In the spring unit 208, the flange portion 243 is brought into contact with the bottom portion 172 of the SS piston 126 with the tubular member 233 fitting the protrusions 173 into the plurality of convex portions 247 of the body portion 242. In this state, the cylindrical member 233 has the concave portion 245 extending to the position of the end surface 173 a of the protruding portion 173. An end surface 173 a of the projecting portion 173 that is an end surface of the SS piston 126 faces an end surface 237 a of the flange portion 237 that is an end surface of the pin member 232. The buffer member 209 is disposed between the end surface 173 a of the projecting portion 173 and the end surface 237 a of the flange portion 237 in the body portion 242 of the cylindrical member 233.

Here, the spring unit 208 contracts when the SS piston 126 approaches the locking retainer 207. When the SS piston 126 comes closest to the retaining retainer 207 and contacts the retaining retainer 207, the spring unit 208 is restricted from further contraction. At that time, in the SS piston 126, the cylindrical portion 171 abuts on the flange portion 223 of the locking retainer 207.

4 and 5, the buffer member 209 has a core portion 251 and a plurality of protruding portions 252. The core part 251 is provided in the center part in the buffer member 209, and has a cylindrical shape.

The protruding portion 252 protrudes outward in the radial direction of the core portion 251 from the outer peripheral surface of the core portion 251, and extends in the axial direction of the core portion 251. The projecting portion 252 has a narrower width in the circumferential direction of the core portion 251 as it moves away from the core portion 251 in the radial direction of the core portion 251. Chamfers 253 are formed at both ends of the protruding portion 252 in the length direction.
The chamfer 253 is inclined so as to approach the core part 251 in the radial direction of the core part 251 toward the end in the length direction of the protruding part 252. As for the protrusion part 252, the shape of the cross section in the surface orthogonal to the central axis of the core part 251 is semicircular except for the chamfer 253. Specifically, four protrusions 252 are formed on the outer peripheral side of the core 251, and are formed at equal division positions in the circumferential direction of the core 251.

Therefore, the buffer member 209 has a cross-shaped cross section on a plane orthogonal to the central axis. The buffer member 209 has a plurality of projecting portions 252 that project radially outward from the central core portion 251 in the radial direction. The plurality of protrusions 252 have a width in the circumferential direction of the buffer member 209 that is narrower toward the outer side in the radial direction, and a length in the axial direction of the buffer member 209 is shorter toward the outer side in the radial direction. Between the protruding portion 252 and the protruding portion 252 that are adjacent to each other in the circumferential direction of the buffer member 209, there is a space in which the radial position of the buffer member 209 is overlapped.

The axial length of the buffer member 209 is such that the end surface 173a of the SS piston 126 and the pin when the spring unit 208 is in the most contracted state due to the SS piston 126 shown in FIG. The distance from the end surface 237a of the member 232 is longer. The maximum outer diameter of the buffer member 209 is the diameter of a circumscribed circle that passes through the distal ends of the plurality of protruding portions 252 in the protruding direction. The maximum outer diameter of the buffer member 209 is slightly larger than the inner diameter of the main portion 246 of the cylindrical member 233, that is, the diameter of the inner peripheral surface 246a.

The shock absorbing member 209 has the end surface 173a of the SS piston 126 when the volume in the natural state before being incorporated into the spring unit 208 is in the most contracted state when the spring unit 208 is incorporated into the stroke simulator 27. It is formed smaller than the volume of the portion surrounded by the end surface 237 a of the pin member 232 and the body 242 of the cylindrical member 233.
Here, the most contracted state when the spring unit 208 is incorporated in the stroke simulator 27 is the state in which the SS piston 126 is in contact with the locking retainer 207 as described above.

A portion surrounded by the SS piston 126, the cylinder wall 122 of the SS cylinder 33, and the lid member 191 constitutes a spring chamber 255. The spring chamber 255 also constitutes the stroke simulator 27. The spring chamber 255 is defined as the SS pressure chamber 181 by the partition seals 151 and 161 shown in FIG.

3, the buffer member 193, the spring 206, the locking retainer 207, the spring unit 208, and the buffer member 209 of the reaction force generation mechanism 127 are disposed in the spring chamber 255. Therefore, the springs 206 and 227 are disposed in the spring chamber 255. The bleeder passage 142 of the SS cylinder 33 communicates with the spring chamber 255. One end of the axial groove 165 of the SS cylinder 33 opens into the circumferential groove 137 and the other end opens into the spring chamber 255.

When the brake simulator 11 is in a non-braking state without input from the brake pedal 11 shown in FIG. 1, the stroke simulator 27 uses the urging force of the spring 227 of the spring unit 208 and the urging force of the spring 206 as shown in FIG. The piston 126 is brought into contact with the cylinder bottom 121 of the SS cylinder 33.
When in the non-braking state, as shown in FIG. 3, the spring unit 208 has one end in contact with the bottom 172 of the SS piston 126 and the other end in contact with the lid 221 of the locking retainer 207. In this state, one end of the spring 206 is in contact with the flange portion 223 of the locking retainer 207, and the other end is in contact with the substrate portion 194 of the lid member 191 fixed to the SS cylinder 33. In this state, the buffer member 193 is separated from the lid portion 221 of the locking retainer 207, and the buffer member 209 is separated from the flange portion 237 of the pin member 232 of the spring unit 208. The springs 206 and 227 urge the SS piston 126 toward the cylinder bottom 121 shown in FIG.

When the primary piston 46 shown in FIG. 2 moves toward the cylinder bottom 41 by the input from the brake pedal 11 shown in FIG. 1, the primary piston 46 pressurizes the brake fluid in the primary pressure chamber 56 as described above. The brake fluid pressurized in the primary pressure chamber 56 is sent from the primary discharge path 69 to the power module 14 shown in FIG.
However, the power module 14 cuts off the hydraulic pressure from the primary discharge path 69 in a normal state. At this time, the power module 14 supplies the brake hydraulic pressure generated electrically to the brake cylinders 15FR, 15RL, 15RR, and 15FL based on the detection result of the stroke sensor 22 and the like.

Further, when the primary piston 46 of the master cylinder 26 shown in FIG. 2 moves to the cylinder bottom 41 side by the input from the brake pedal 11, the primary piston 46 is pressed via the spring unit 57 and the secondary piston 47 is moved to the cylinder bottom. Move to the 41st side. Then, the secondary piston 47 pressurizes the brake fluid in the secondary pressure chamber 61 as described above. The brake fluid pressurized in the secondary pressure chamber 61 is sent from the secondary discharge path 68 to the power module 14 shown in FIG.
However, similarly to the above, the power module 14 cuts off the hydraulic pressure from the secondary discharge path 68 in a normal state. For this reason, the pressurized brake fluid in the secondary pressure chamber 61 shown in FIG. 2 is introduced into the SS pressure chamber 181 of the stroke simulator 27 via the introduction passage 141, and the brake fluid in the SS pressure chamber 181 is added. Press.

When the brake fluid pressure in the SS pressure chamber 181 increases, the SS piston 126 moves away from the cylinder bottom 121, that is, in a direction approaching the lid member 191. Then, the SS piston 126 first contracts the spring 227 of the spring unit 208 shown in FIG. 3 against its urging force. At that time, the spring 227 urges the SS piston 126 against the brake fluid pressure in the SS pressure chamber 181 and causes the brake pedal 11 shown in FIG. 1 to react against the contraction of the spring 227 shown in FIG. Power is granted.

When the brake fluid pressure in the SS pressure chamber 181 further increases, the SS piston 126 causes the buffer member 209 to abut against the flange portion 237 of the pin member 232 while further reducing the length of the spring 227, and the buffer member 209 is attached thereto. Shrink against the power. At this time, the buffer member 209 also biases the SS piston 126 against the brake fluid pressure in the SS pressure chamber 181, and the spring 227 and the buffer member 209 shown in FIG. A reaction force according to the length is given.
When the buffer member 209 is further contracted, the cylindrical portion 171 of the SS piston 126 comes into contact with the flange portion 223 of the locking retainer 207. Thereby, the spring 227 and the buffer member 209 are in a state in which further contraction is restricted.

Here, when the buffer member 209 is contracted and deformed in the direction in which the length in the axial direction is contracted, the buffer member 209 is deformed so as to expand the portion contracted in the axial direction to other than the axial direction. Even if the buffer member 209 swells in this manner, the buffer member 209 does not interfere with the spring 227 because the body 242 of the cylindrical member 233 is interposed between the buffer member 209 and the spring 227.

When the brake fluid pressure in the SS pressure chamber 181 is further increased, the SS piston 126 contracts the spring 206 against the biasing force while the spring 227 and the buffer member 209 are contracted. At this time, the spring 206 also urges the SS piston 126 against the brake fluid pressure in the SS pressure chamber 181, and the spring pedal 227 shown in FIG. 1, the spring 227, the buffer member 209, and the spring 206 shown in FIG. A reaction force corresponding to the contraction length is applied.

When the brake fluid pressure in the SS pressure chamber 181 further increases, the SS piston 126 causes the locking retainer 207 to move to the buffer member 193 while further contracting the spring 206 while the spring 227 and the buffer member 209 are contracted. The buffer member 193 is contracted against the urging force by abutting. At that time, the buffer member 193 also urges the SS piston 126 against the brake fluid pressure of the SS pressure chamber 181, and the brake pedal 11 shown in FIG. 1 is moved to the spring 227, buffer member 209, spring shown in FIG. A reaction force corresponding to the contraction of 206 and the buffer member 193 is applied.

As described above, the stroke simulator 27 applies a reaction force corresponding to the depression force of the brake pedal 11 shown in FIG. 1 to the brake pedal 11 to generate a pseudo operation feeling.

The stroke simulator 27 contracts all of the spring unit 208, the buffer member 209, the spring 206, and the buffer member 193 when the SS piston 126 shown in FIG. 2 is in a full stroke state that is located farthest from the cylinder bottom 121. ing. The SS piston 126 in the full stroke state abuts against the retaining retainer 207 and contracts the spring unit 208 most. In this state, the volume of the buffer member 209 in the natural state is larger than the volume of the portion surrounded by the end surface 173a of the SS piston 126, the end surface 237a of the pin member 232, and the body 242 of the cylindrical member 233 shown in FIG. Is formed small. That is, the volume of the buffer member 209 is larger than the volume of the portion surrounded by the end surface 173a of the SS piston 126, the end surface 237a of the pin member 232, and the body 242 of the cylindrical member 233 in the full stroke state of the SS piston 126. It is formed small.

Specifically, as described above, the buffer member 209 reduces the volume by providing a space between the protruding portion 252 and the protruding portion 252 that are arranged at intervals in the circumferential direction. Therefore, even in the full stroke state of the SS piston 126, a larger volume than the natural volume of the buffer member 209 is ensured between the end surfaces 173a and 237a in the body portion 242 of the cylindrical member 233.

As a result, in a portion surrounded by the end surface 173a of the SS piston 126, the end surface 237a of the pin member 232, and the cylindrical member 233, other than the axial direction that occurs when the buffer member 209 is deformed in the direction of reducing the axial length. There is a space for receiving the deformation until the buffer member 209 has the axial length shortened the most.
Therefore, the deformation that occurs when the buffer member 209 shortens the axial length can be satisfactorily released, and the contact pressure between the buffer member 209 and the tubular member 233 can be suppressed.

Specifically, when the buffer member 209 is deformed in the direction of reducing the length in the axial direction, the buffer member 209 swells toward a gap between the protrusions 252 and the protrusions 252 arranged at intervals in the circumferential direction.

Patent Documents 1 and 2 describe a stroke simulator that generates a reaction force in response to an operation of a brake pedal. In the stroke simulator of Patent Document 1, coil springs are arranged on the outer peripheral side of the buffer member without interposing other members therebetween. For this reason, a buffer member may interfere with a coil spring at the time of a deformation | transformation, and may affect a reaction force characteristic. In order to suppress such interference with the coil spring when the buffer member is deformed, it is necessary to widen the distance between the buffer member and the coil spring, resulting in an increase in size.
Moreover, since the stroke simulator described in Patent Document 2 does not have a buffer member, good reaction force characteristics cannot be obtained. Here, the reaction force characteristic is a characteristic of the magnitude of the reaction force with respect to the operation amount of the brake pedal.

In the first embodiment, the cylindrical member 233 is provided on the retainer 226 that defines the length of the spring 227, the spring 227 is disposed on the outer peripheral side of the cylindrical member 233, and the buffer member 209 is disposed on the inner peripheral side. Therefore, even if the buffer member 209 is deformed in the direction of reducing the axial length, the cylindrical member 233 is interposed, and thus the spring 227 is not interfered. Therefore, good reaction force characteristics can be obtained. In addition, since the distance between the buffer member 209 and the spring 227 can be reduced, an increase in size can be suppressed.

In addition, the volume of the buffer member 209 is smaller than the volume of the portion surrounded by the end surface 173a of the SS piston 126, the end surface 237a of the pin member 232, and the cylindrical member 233 in the full stroke state of the SS piston 126. Yes. Therefore, even if the buffer member 209 is deformed in the direction of reducing the axial length, the contact pressure generated between the buffer member 209 and the cylindrical member 233 can be suppressed. Therefore, even better reaction force characteristics can be obtained.

Further, the buffer member 209 has a shape having projecting portions 252 that project radially from the central core portion 251 in the radial direction. For this reason, even if it deform | transforms in the direction contracted to an axial direction, the part which swells other than an axial direction can be escaped favorably, and the contact pressure produced between the cylindrical members 233 can be suppressed further. Therefore, even better reaction force characteristics can be obtained.

Further, due to the shape of the buffer member 209, even when the SS piston 126 is in a full stroke state, a volume larger than the volume of the buffer member 209 in the natural state is secured between the end surfaces 173a and 237a in the cylindrical member 233. For this reason, the shape of the cylindrical member 233 becomes simple, and the manufacturing cost can be suppressed.
In the first embodiment described above, the example in which the protruding portion 252 of the buffer member 209 extends in the axial direction of the core portion 251 has been described. However, the present embodiment is not limited to this, and for example, extends in the circumferential direction. It may be.
Even in this case, the volume of the buffer member 209 is smaller than the volume of the portion surrounded by the end surface 173a of the SS piston 126, the end surface 237a of the pin member 232, and the cylindrical member 233 in the full stroke state of the SS piston 126. If it is made, the contact pressure produced between the cylindrical members 233 can be suppressed.

(Second Embodiment)
Next, the second embodiment will be described mainly with reference to FIGS. 6 and 7 focusing on the differences from the first embodiment. In addition, about the site | part which is common in 1st Embodiment, it represents with the same name and the same code | symbol.

In the second embodiment, the cylindrical member 233A of the retainer 226 is partially different from the cylindrical member 233 of the first embodiment. Specifically, the trunk portion 242A is partially different from the trunk portion 242 of the first embodiment. A plurality (specifically, four places) of concave portions 245A that are longer in the axial direction of the trunk portion 242A than the concave portion 245 of the first embodiment are formed in the trunk portion 242A.
Therefore, a plurality of (specifically, four) convex portions 247A that are longer in the axial direction of the trunk portion 242A than the convex portion 247 of the first embodiment are formed on the trunk portion 242A. The cylindrical member 233A is a concave portion in a state where the projecting portions 173 of the SS piston 126 are fitted into the plurality of convex portions 247A of the body portion 242A and the flange portion 243 is in contact with the bottom portion 172 of the SS piston 126. 245A extends from the end surface 173a of the projecting portion 173 to the contact portion 241 side.

In the second embodiment, the buffer member 209A is partially different from the buffer member 209 of the first embodiment. The buffer member 209A has a columnar shape. The buffer member 209 </ b> A has an annular chamfer 253 </ b> A formed on the outer peripheral portion of both end portions in the axial direction. The chamfer 253A has a tapered shape in which the outer diameter becomes smaller as it is positioned closer to the end of the buffer member 209A in the axial direction. The outer diameter of the buffer member 209A is slightly larger than the diameter of the inscribed circle passing through the leading ends in the protruding direction of the plurality of convex portions 247A shown in FIG. 7, and the main portion 246 of the trunk portion 242A shown in FIG. The diameter is slightly larger than the diameter of the inner peripheral surface 246a.

Also in the second embodiment, the stroke simulator 27 causes the SS piston 126 in a full stroke state to abut on the locking retainer 207 and contracts the spring unit 208 most. In this state, the volume of the buffer member 209A is larger than the volume between the end surfaces 173a and 237a of the portion surrounded by the end surface 173a of the SS piston 126, the end surface 237a of the pin member 232, and the body 242A of the cylindrical member 233A. The volume in the natural state is small.

Specifically, by forming the plurality of concave portions 245A in the trunk portion 242A as described above, the trunk portion 242A increases the inner volume as compared with the case where there is no concave portion 245A. In this manner, the cylindrical member 233A secures a volume larger than the volume of the buffer member 209A in the natural state between the end surfaces 173a and 237a in the barrel 242A even in the full stroke state of the SS piston 126. Yes.

As a result, the deformation in the direction other than the axial direction that occurs when the buffer member 209A is deformed in the direction of reducing the axial length can be well escaped to the concave portion 245A. Thereby, the contact pressure of the buffer member 209A and the cylindrical member 233A that are deformed can be suppressed.

In the second embodiment, by forming the plurality of concave portions 245A in the body portion 242A, even in the full stroke state of the SS piston 126, a volume larger than the volume in the natural state of the buffer member 209A is increased. It is secured between the inner end faces 173a and 237a. For this reason, the freedom degree of the shape of buffer member 209A becomes high. Therefore, even better reaction force characteristics can be obtained.

(Third embodiment)
Next, the third embodiment will be described mainly with reference to FIGS. 8 to 10 focusing on the differences from the first embodiment. In addition, about the site | part which is common in 1st Embodiment, it represents with the same name and the same code | symbol.

In the third embodiment, as shown in FIGS. 8 to 10, the buffer member 209B is partially different from the buffer member 209 of the first embodiment. The buffer member 209 </ b> B has a through-hole 271 that penetrates in the axial direction at the center, and has a cylindrical shape. An annular chamfer 253B is formed on the outer periphery of both end portions in the axial direction of the buffer member 209B. The chamfer 253B has a tapered shape in which the outer diameter becomes smaller as it is positioned closer to the end of the buffer member 209B in the axial direction. The outer diameter of the buffer member 209 </ b> B is slightly larger than the inner diameter of the main body 246 of the body 242, that is, the diameter of the inner peripheral surface 246 a.

Also in the third embodiment, the stroke simulator 27 causes the SS piston 126 in the full stroke state to abut on the locking retainer 207 so that the spring unit 208 is most contracted. In this state, the volume of the buffer member 209B in the natural state is smaller than the volume of the portion surrounded by the end surface 173a of the SS piston 126, the end surface 237a of the pin member 232, and the cylindrical member 233. Yes.

Specifically, as described above, the buffer member 209B has a cylindrical shape and is provided with a space on the inner side, so that the volume of the buffer member 209B in the natural state is larger even in the full stroke state of the SS piston 126. A volume is secured between the end surfaces 173a and 237a in the cylindrical member 233.

As a result, the deformation in the direction other than the axial direction that occurs when the buffer member 209B is deformed in the direction of reducing the axial length can be well escaped to the inner space. Thereby, the contact pressure of the buffer member 209 </ b> B and the tubular member 233 that are deformed can be suppressed.

In the third embodiment, since the buffer member 209B has a cylindrical shape, the end surface 173a in the tubular member 233 has a volume larger than the volume of the buffer member 209B in the natural state even in the full stroke state of the SS piston 126. , 237a. For this reason, manufacture of buffer member 209B and cylindrical member 233 becomes easy, and it becomes possible to control manufacturing cost.

(Fourth embodiment)
Next, the fourth embodiment will be described mainly with reference to FIGS. 11 and 12 focusing on the differences from the first embodiment. In addition, about the site | part which is common in 1st Embodiment, it represents with the same name and the same code | symbol.

In the fourth embodiment, as shown in FIG. 11, the buffer member 209C is partially different from the buffer member 209 of the first embodiment. The buffer member 209C is cylindrical. The outer diameter of the buffer member 209 </ b> C is smaller than the inner diameter of the main body 246 of the body 242, that is, the diameter of the inner peripheral surface 246 a.

Also in the fourth embodiment, in the stroke simulator 27, the SS piston 126 in the full stroke state contacts the locking retainer 207, and the spring unit 208 is most contracted. In this state, the volume of the buffer member 209C in the natural state is smaller than the volume of the portion surrounded by the end surface 173a of the SS piston 126, the end surface 237a of the pin member 232, and the cylindrical member 233.

Specifically, as described above, by setting the outer diameter of the buffer member 209C in the natural state to be smaller than the inner diameter of the body portion 242, that is, the diameter of the inner peripheral surface 246a, even in the full stroke state of the SS piston 126 A volume larger than the volume of the buffer member 209C in the natural state is secured between the end surfaces 173a and 237a in the cylindrical member 233.

As a result, as shown in FIGS. 11 to 12, the deformation in the direction other than the axial direction that occurs when the buffer member 209 </ b> C is deformed in the direction of reducing the axial length can be released to the outer space in the radial direction. . Thereby, the contact pressure of the buffer member 209C and the cylindrical member 233 that are deformed can be suppressed.

In the fourth embodiment, the buffer member 209 </ b> C has a columnar shape having a smaller diameter than the inner diameter of the main body 246 of the body 242 of the cylindrical member 233, so that even when the SS piston 126 is in a full stroke state, A volume larger than the volume in the state is secured between the end faces 173a and 237a in the cylindrical member 233. For this reason, manufacture of buffer member 209C and cylindrical member 233 becomes easy, and it becomes possible to control manufacturing cost.

(Fifth embodiment)
Next, the fifth embodiment will be described mainly based on FIGS. 13 to 15 with a focus on differences from the first embodiment. In addition, about the site | part which is common in 1st Embodiment, it represents with the same name and the same code | symbol.

In the fifth embodiment, as shown in FIGS. 13 to 15, the buffer member 209D is partially different from the buffer member 209 of the first embodiment. The buffer member 209 </ b> D has a cylindrical shape, and an annular chamfer 253 </ b> D is formed on the outer peripheral portion of both end portions in the axial direction. The chamfer 253D has a tapered shape in which the outer diameter becomes smaller as it is positioned on the end side in the axial direction of the buffer member 209D. The outer diameter of the buffer member 209 </ b> D is slightly larger than the inner diameter of the main body 246 of the body 242, that is, the diameter of the inner peripheral surface 246 a.

Also in the fifth embodiment, the stroke simulator 27 causes the SS piston 126 in the full stroke state to abut on the locking retainer 207 and contracts the spring unit 208 most. In this state, the volume of the buffer member 209D in the natural state is smaller than the volume of the portion surrounded by the end surface 173a of the SS piston 126, the end surface 237a of the pin member 232, and the cylindrical member 233. Yes.

Specifically, as described above, by forming the annular chamfer 253D at both axial ends of the buffer member 209D, the volume of the buffer member 209D in the natural state even in the full stroke state of the SS piston 126 A larger volume is ensured between the end surfaces 173a and 237a in the cylindrical member 233.

As a result, the deformation in the direction other than the axial direction that occurs when the buffer member 209D is deformed in the direction of reducing the axial length can be well escaped to the space outside the chamfer 253D. Thereby, the contact pressure of the buffer member 209D and the cylindrical member 233 that are deformed can be suppressed.

In the fifth embodiment, the chamfer 253D is formed at both ends of the cylindrical buffer member 209D, so that the volume larger than the volume of the buffer member 209D in the natural state can be obtained even in the full stroke state of the SS piston 126. It is ensured between the end surfaces 173a and 237a in the shaped member 233. For this reason, manufacture of buffer member 209D and cylindrical member 233 becomes easy, and it becomes possible to control manufacturing cost.

As a stroke simulator based on the embodiment described above, for example, the following modes can be considered.
As a first aspect, there is a stroke simulator in which hydraulic pressure is introduced from a master cylinder that supplies hydraulic pressure to a brake cylinder provided on a wheel and hydraulic reaction force is transmitted to a brake pedal. The stroke simulator includes a cylinder into which hydraulic pressure from the master cylinder is introduced, a piston that moves within the cylinder by the hydraulic pressure, a reaction force spring that biases the piston against the hydraulic pressure, And a retainer for defining the length of the reaction force spring.
The retainer includes a cylindrical member and a pin member that can move relative to the cylindrical member. The cylindrical member has the reaction force spring disposed on the outer peripheral side and an elastic member disposed on the inner peripheral side. A cylindrical member is provided on a retainer that defines the length of the reaction force spring, a reaction force spring is disposed on the outer peripheral side of the cylindrical member, and an elastic member is disposed on the inner peripheral side.
As a second aspect, in the first aspect, the elastic member has a volume surrounded by the end face of the piston, the end face of the pin member, and the cylindrical member in the full stroke state of the piston. It is formed smaller than. Therefore, even if the elastic member is deformed in the direction of reducing the axial length, the cylindrical member is interposed so that the elastic member does not interfere with the reaction force spring. Therefore, good reaction force characteristics can be obtained. In addition, since the distance between the elastic member and the reaction force spring can be reduced, an increase in size can be suppressed. In addition, the volume of the elastic member is formed smaller than the volume of the portion surrounded by the end face of the piston, the end face of the pin member, and the cylindrical member in the full stroke state of the piston. Therefore, even if the elastic member is deformed in the direction of reducing the axial length, contact pressure generated between the elastic member and the cylindrical member can be suppressed. Therefore, even better reaction force characteristics can be obtained.
As a third aspect, in the second aspect, the elastic member includes a core part that forms a radial center part and a protruding part that protrudes radially outward from the outer peripheral surface of the core part.
As a fourth aspect, in the third aspect, in the elastic member, the protruding portion extends in the axial direction.
As a fifth aspect, in the third aspect, the elastic member is such that the protruding portion extends in the circumferential direction.
As a sixth aspect, in the second aspect, the tubular member has a convex portion protruding radially inward and a concave portion recessed radially outward with respect to the convex portion.
As a seventh aspect, in the second aspect, the elastic member has a cylindrical shape.
As an eighth aspect, in the second aspect, the elastic member has a cylindrical shape whose diameter is smaller than the inner diameter of the cylindrical member.
As a ninth aspect, in the second aspect, the elastic member has a cylindrical shape in which an annular chamfer is formed at an axial end portion thereof.

The present invention can be applied to a stroke simulator that generates a reaction force against the operation of a brake pedal.

11 Brake pedal 15FR, 15RL, 15RR, 15FL Brake cylinder 26 Master cylinder 27 Stroke simulator 33 SS cylinder (cylinder)
126 SS piston (piston)
173a End face 209, 209A to 209D Buffer member (elastic member)
226 Retainer (Retainer)
227 Spring (Reaction force spring)
232 Pin member 233, 233A Cylindrical member 237a End face

Claims (9)

1. A stroke simulator in which hydraulic pressure is introduced from a master cylinder that supplies hydraulic pressure to a braking cylinder provided on a wheel and hydraulic reaction force is transmitted to a brake pedal,
   A cylinder into which hydraulic pressure from the master cylinder is introduced;
   A piston that moves in the cylinder by the hydraulic pressure;
   A reaction force spring that urges the piston against the hydraulic pressure;
   A retainer for defining the length of the reaction spring;
   With
   The retainer has a tubular member and a pin member that can move relative to the tubular member;
   The cylindrical member has the reaction force spring disposed on the outer peripheral side and an elastic member disposed on the inner peripheral side.
   Stroke simulator.
2. The said elastic member is formed so that the volume is smaller than the volume of the part enclosed by the end surface of this piston, the end surface of the said pin member, and the said cylindrical member in the full stroke state of the said piston. Stroke simulator.
3. 3. The stroke simulator according to claim 2, wherein the elastic member includes a core portion that forms a central portion in the radial direction and a protruding portion that protrudes radially outward from the outer peripheral surface of the core portion.
4. The stroke simulator according to claim 3, wherein the elastic member has the protrusion extending in the axial direction.
5. The stroke simulator according to claim 3, wherein the elastic member has the protruding portion extending in a circumferential direction.
6. The stroke simulator according to claim 2, wherein the cylindrical member has a convex portion protruding radially inward and a concave portion recessed radially outward with respect to the convex portion.
7. The stroke simulator according to claim 2, wherein the elastic member has a cylindrical shape.
8. The stroke simulator according to claim 2, wherein the elastic member has a cylindrical shape whose diameter is smaller than an inner diameter of the cylindrical member.
9. The stroke simulator according to claim 2, wherein the elastic member has a cylindrical shape in which an annular chamfer is formed at an axial end portion thereof.

Images