WO2019230400A1

WO2019230400A1 - Master cylinder

Info

Publication number: WO2019230400A1
Application number: PCT/JP2019/019319
Authority: WO
Inventors: 峻立川
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2018-05-29
Filing date: 2019-05-15
Publication date: 2019-12-05
Also published as: JPWO2019230400A1; CN112203912A; CN112203912B; JP7034276B2

Abstract

This master cylinder is provided with a seal (52) that is disposed within a circumferential groove (33) formed so as to have an opening in an inner circumferential surface (15a) of a cylinder body (15), that has an inner circumference that comes into sliding contact with a piston (18), and that defines the outside of the cylinder body (15) and a supply channel (48). The seal (52) has: an inner circumferential lip (102) that comes into sliding contact with an outer circumferential surface (18z) of the piston (18); and an outer circumferential lip (103) that abuts against the circumferential groove (33) of the cylinder body (15). The outer circumferential lip (103) has formed at a leading end (121) thereof a passage way (122) that connects between the inner circumferential side and the outer circumferential side of the outer circumferential lip (103).

Description

Master cylinder

The present invention relates to a master cylinder that supplies hydraulic pressure to a brake cylinder of a vehicle.
This application claims priority on May 29, 2018 based on Japanese Patent Application No. 2018-102318 for which it applied to Japan, and uses the content for it here.

Some master cylinders are provided with a seal for defining a replenishment path communicating with a reservoir and the outside of the cylinder body in a circumferential groove of the cylinder body (see, for example, Patent Document 1).

JP 2006-123879 A

Demand for quality improvement in master cylinders.

The present invention provides a master cylinder capable of improving quality.

According to one aspect of the present invention, the master cylinder is disposed in a circumferential groove formed by opening in the inner peripheral surface of the cylinder body, and the inner periphery is in sliding contact with the piston, With a seal that defines The seal includes an inner peripheral lip portion that protrudes from an annular base portion and slidably contacts the outer peripheral surface of the piston, and an outer peripheral lip portion that contacts the peripheral groove of the cylinder body. The outer peripheral lip portion is formed with a passage communicating with the inner peripheral side and the outer peripheral side of the outer peripheral lip portion at the distal end portion.

According to the master cylinder described above, the quality can be improved.

It is sectional drawing which shows the master cylinder of 1st Embodiment. It is a fragmentary sectional view which shows the principal part of the master cylinder of 1st Embodiment. It is a fragmentary sectional view which shows the division seal of the master cylinder of 1st Embodiment. It is a front view which shows the division seal of the master cylinder of 1st Embodiment. It is a fragmentary sectional view in the evacuation state which shows the principal part of the master cylinder of a 1st embodiment. It is a fragmentary sectional view in the evacuation state which shows the principal part of another master cylinder. It is a fragmentary sectional view in the evacuation state which shows the important section of the master cylinder of a 2nd embodiment. It is a fragmentary sectional view in the evacuation state which shows the principal part of the master cylinder of a 3rd embodiment.

[First Embodiment]
A first embodiment according to the present invention will be described with reference to FIGS. In the master cylinder 11 according to the first embodiment shown in FIG. 1, a force corresponding to an operation amount of a brake pedal (not shown) is introduced through an output shaft of a brake booster (not shown). The master cylinder 11 generates a brake fluid pressure corresponding to the operation amount of the brake pedal. A reservoir 12 (only a part of which is shown in FIG. 1) for supplying and discharging brake fluid to / from the master cylinder 11 is attached to the master cylinder 11 on the upper side in the vertical direction. In the present embodiment, the reservoir 12 is directly attached to the master cylinder 11, but the reservoir may be disposed at a position separated from the master cylinder 11, and the reservoir and the master cylinder 11 may be connected by piping. .

The master cylinder 11 has a cylinder body 15 made of metal that is formed by processing a single material into a bottomed cylinder having a bottom 13 and a cylinder 14. The cylinder body 15 has an opening 16 on one side in the axial direction and a bottom 13 on the other side in the axial direction. A metal primary piston 18 (piston) is movably disposed on the opening 16 side in the cylinder body 15 so as to partially protrude from the cylinder body 15. Similarly, a metal secondary piston 19 is movably disposed on the bottom 13 side of the primary piston 18 in the cylinder body 15. An inner peripheral hole 21 having a bottom surface is formed in the primary piston 18. The secondary piston 19 has an inner peripheral hole 22 having a bottom surface. The master cylinder 11 is a so-called plunger type. The master cylinder 11 is a tandem type master cylinder having two primary pistons 18 and secondary pistons 19 as described above. The present invention is not limited to the application to the tandem type master cylinder, and if it is a plunger type master cylinder, a single type master cylinder in which one piston is arranged in the cylinder body, or three or more types. The present invention can be applied to any plunger type master cylinder such as a master cylinder having a plurality of pistons.

The cylinder body 15 has a mounting base portion 23 protruding outward in the radial direction of the cylindrical portion 14 (hereinafter referred to as the cylinder radial direction), and in the circumferential direction of the cylindrical portion 14 (hereinafter referred to as the cylinder circumferential direction). Are integrally formed at predetermined positions. The mounting base 23 is formed with mounting holes 24 and mounting holes 25 for mounting the reservoir 12. In the present embodiment, the mounting hole 24 and the mounting hole 25 are positioned in the axial direction (hereinafter referred to as the cylinder axis) of the cylinder portion 14 of the cylinder body 15 in a state where the positions in the cylinder circumferential direction coincide with each other. Is formed at the upper part of the cylinder body 15 in the vertical direction. The cylinder body 15 is disposed in the vehicle in such a posture that the axial direction of the cylindrical portion 14 (hereinafter referred to as the cylinder axial direction) is along the vehicle longitudinal direction. Hereinafter, the opening 16 side of the cylinder body 15 in the cylinder axial direction is referred to as a cylinder opening side, and the bottom 13 side of the cylinder body 15 in the cylinder axial direction is referred to as a cylinder bottom side.

A secondary discharge path 26 that is a brake fluid discharge path is formed in the vicinity of the bottom 13 in the cylinder axis direction on the mounting base 23 side of the cylinder portion 14 of the cylinder body 15. Further, a primary discharge path 27 (discharge path) that is a brake liquid discharge path is formed on the cylinder opening side of the cylinder body 15 with respect to the secondary discharge path 26. In other words, the cylinder body 15 has a secondary discharge path 26 and a primary discharge path 27, both of which are brake fluid discharge paths. Although not shown, the secondary discharge path 26 and the primary discharge path 27 communicate with a brake cylinder such as a disc brake or a drum brake via a brake pipe, and discharge brake fluid toward the brake cylinder. In the present embodiment, the secondary discharge path 26 and the primary discharge path 27 are formed so that the positions in the cylinder axial direction are shifted in a state where the positions in the cylinder circumferential direction coincide with each other.

A sliding inner diameter portion 28 is formed on the inner peripheral portion of the cylinder portion 14 of the cylinder body 15 on the cylinder bottom side. The sliding inner diameter portion 28 protrudes inward in the cylinder radial direction from the inner peripheral portion of the cylindrical portion 14 on both sides in the cylinder axial direction. The sliding inner diameter portion 28 has an annular shape in the cylinder circumferential direction. The secondary piston 19 is slidably fitted to the minimum inner diameter surface 28 a of the sliding inner diameter portion 28. The secondary piston 19 is guided by the minimum inner diameter surface 28a and moves in the cylinder axial direction. A sliding inner diameter portion 29 is formed on an inner peripheral portion of the cylinder portion 14 of the cylinder body 15 on the cylinder opening side. The sliding inner diameter portion 29 protrudes inward in the cylinder radial direction from the inner peripheral portion of the cylinder portion 14 on the cylinder bottom side. The sliding inner diameter portion 29 has an annular shape in the cylinder circumferential direction. The primary piston 18 is slidably fitted to the minimum inner diameter surface 29 a of the sliding inner diameter portion 29. The primary piston 18 is guided by the minimum inner diameter surface 29a and moves in the cylinder axis direction.

The sliding inner diameter portion 28 is formed with a circumferential groove 30 and a circumferential groove 31 that are formed in this order from the bottom side of the cylinder in a plurality of positions, in the cylinder axial direction, in a plurality of shapes, specifically in any two places.
In addition, the sliding inner diameter portion 29 is also formed with a circumferential groove 32 and a circumferential groove 33 that are formed in this order from the cylinder bottom side by shifting the position in the cylinder axial direction and forming a plurality of, specifically, two of them in an annular shape. . The

circumferential grooves

30 and 31 have an annular shape in the cylinder circumferential direction and have a shape that is recessed outward in the cylinder radial direction from the minimum inner diameter surface 28a constituting the inner circumferential surface 15a of the cylinder body 15. The

circumferential grooves

32 and 33 have an annular shape in the cylinder circumferential direction and have a shape that is recessed outward in the cylinder radial direction from the minimum inner diameter surface 29a constituting the inner circumferential surface 15a of the cylinder body 15. The cylinder opening side from the circumferential groove 33 is an opening-side inner diameter surface 16 a that constitutes the inner circumferential surface 15 a of the cylinder body 15. The circumferential groove 33 has a shape that is recessed outward in the cylinder radial direction from the opening-side inner diameter surface 16a. The opening side inner diameter surface 16a is slightly larger in diameter than the minimum inner diameter surface 29a. The circumferential grooves 30 to 33 are formed in the cylinder body 15 so as to open to the inner circumferential surface 15 a of the cylinder body 15. All of the circumferential grooves 30 to 33 are formed by cutting.

Of the circumferential grooves 30 to 33, the circumferential groove 30 closest to the cylinder bottom is formed in the vicinity of the mounting hole 24 on the cylinder bottom side of the mounting hole 24 and the mounting hole 25. An annular piston seal 35 is disposed in the circumferential groove 30 so as to be held in the circumferential groove 30.

An annular opening groove 37 is formed on the cylinder opening side of the sliding inner diameter portion 28 of the cylinder body 15 on the cylinder opening side, and is recessed outward in the cylinder radial direction from the minimum inner diameter surface 28a. The opening groove 37 opens a communication hole 36 drilled from the mounting hole 24 on the cylinder bottom side into the cylindrical portion 14. Here, the opening groove 37 and the communication hole 36 constitute a secondary supply path 38 provided in the cylinder body 15 and always communicating with the reservoir 12. In other words, the cylinder body 15 has a secondary supply path 38 that communicates with the reservoir 12.

A communication groove 41 that opens to the circumferential groove 30 on the cylinder bottom side of the sliding inner diameter portion 28 of the cylinder body 15 and extends linearly from the circumferential groove 30 toward the cylinder bottom side in the cylinder axial direction. However, it is formed so as to be recessed outward in the cylinder radial direction from the minimum inner diameter surface 28a. The communication groove 41 communicates the secondary discharge passage 26 and the circumferential groove 30 formed at a position between the bottom portion 13 and the circumferential groove 30 and in the vicinity of the bottom portion 13 via a secondary pressure chamber 68 described later. .

In the inner diameter sliding portion 28 of the cylinder body 15, the circumferential groove 31 is formed on the side opposite to the circumferential groove 30 of the opening groove 37 in the cylinder axial direction, that is, on the cylinder opening side. An annular partition seal 42 is disposed in the circumferential groove 31 so as to be held in the circumferential groove 31.

The above-mentioned circumferential groove 32 is formed in the sliding inner diameter portion 29 of the cylinder body 15 in the vicinity of the mounting hole 25 on the cylinder opening side. An annular piston seal 45 is disposed in the circumferential groove 32 so as to be held in the circumferential groove 32.

An annular opening groove 47 is formed on the cylinder opening side of the circumferential groove 32 in the sliding inner diameter portion 29 of the cylinder body 15 so as to be recessed outward in the cylinder radial direction from the minimum inner diameter surface 29a. The opening groove 47 opens a communication hole 46 formed in the cylinder opening 14 from the mounting hole 25 on the cylinder opening side. Here, the opening groove 47 and the communication hole 46 mainly constitute a primary supply path 48 (supply path) provided in the cylinder body 15 and always communicating with the reservoir 12. In other words, the cylinder body 15 has a primary supply path 48 that communicates with the reservoir 12.

A communication groove 51 that opens to the circumferential groove 32 on the cylinder bottom side of the sliding inner diameter portion 29 of the cylinder body 15 and extends linearly from the circumferential groove 32 toward the cylinder bottom side in the cylinder axial direction. However, it is formed so as to be recessed outward in the cylinder radial direction from the minimum inner diameter surface 29a. The communication groove 51 has a primary discharge passage 27 formed between the circumferential groove 31 and the circumferential groove 32 and in the vicinity of the circumferential groove 31, and the circumferential groove 32 via a primary pressure chamber 85 described later. Communicate.

A circumferential groove 33 is formed in the sliding inner diameter portion 29 of the cylinder body 15 on the side opposite to the circumferential groove 32 of the opening groove 47, that is, on the cylinder opening side. An annular partition seal 52 (seal) is disposed in the circumferential groove 33 so as to be held in the circumferential groove 33.

The secondary piston 19 disposed on the cylinder bottom side of the cylinder body 15 includes a first cylindrical portion 55, a bottom portion 56 formed on one side in the axial direction of the first cylindrical portion 55, and a first cylinder of the bottom portion 56. It has the shape which has the 2nd cylindrical part 57 formed in the opposite side to the shape part 55. FIG. The inner peripheral hole 22 is formed by the first cylindrical portion 55 and the bottom portion 56 among these. The secondary piston 19 has an inner circumference of each of the piston seal 35 and the partition seal 42 provided on the sliding inner diameter portion 28 of the cylinder body 15 in a state where the first cylindrical portion 55 is disposed on the cylinder bottom side of the cylinder body 15. And is slidably fitted.

In the outer peripheral portion on the end side opposite to the bottom portion 56 of the first cylindrical portion 55, an annular concave portion 59 that is recessed radially inward from the largest outer diameter surface 19 a having the largest diameter on the outer peripheral surface 19 z of the secondary piston 19. Is formed. In the recess 59, a plurality of ports 60 penetrating in the cylinder radial direction are formed on the bottom 56 side so as to be radially arranged at equal intervals in the cylinder circumferential direction.

Between the secondary piston 19 and the bottom 13 of the cylinder body 15, there is provided an interval adjusting portion 63 including a secondary piston spring 62 that determines the interval in a non-braking state in which there is no input from an output shaft of a brake booster (not shown). ing. The interval adjusting portion 63 is connected to the locking member 64 that contacts the bottom portion 13 of the cylinder body 15 and the locking member 64 so as to slide only within a predetermined range, and contacts the bottom portion 56 of the secondary piston 19. And a locking member 65. The secondary piston spring 62 is interposed between the locking member 64 and the locking member 65.

A portion formed by being surrounded by the bottom 13 of the cylinder body 15 and the cylinder bottom side of the cylinder portion 14 and the secondary piston 19 generates a brake fluid pressure and supplies the brake fluid pressure to the secondary discharge passage 26. 68. In other words, the secondary piston 19 forms a secondary pressure chamber 68 that supplies hydraulic pressure to the secondary discharge passage 26 between the secondary piston 19 and the cylinder body 15. The secondary pressure chamber 68 communicates with the secondary supply path 38, that is, the reservoir 12 when the secondary piston 19 is in a position for opening the port 60 to the secondary supply path 38.

The partition seal 42 disposed and held in the circumferential groove 31 of the cylinder body 15 is an integrally molded product made of synthetic rubber. The section seal 42 has a C-shape in which one side of the cross section on the plane including the center line is open to the cylinder opening side. The partition seal 42 is in sliding contact with the outer peripheral surface 19z of the secondary piston 19 moving in the cylinder axial direction, and the outer periphery is in contact with the peripheral groove 31 of the cylinder body 15. Thus, the partition seal 42 always seals the gap between the secondary piston 19 and the partition seal 42 of the cylinder body 15.

The piston seal 35 disposed and held in the circumferential groove 30 of the cylinder body 15 is an integrally molded product made of synthetic rubber. The piston seal 35 has a C-shape in which one side of the cross section on the surface including the center line is open to the cylinder bottom side. The inner periphery of the piston seal 35 is in sliding contact with the outer peripheral surface 19z of the secondary piston 19 that moves in the cylinder axial direction. Further, the outer periphery of the piston seal 35 abuts on the circumferential groove 30 of the cylinder body 15. The piston seal 35 provided in the circumferential groove 30 can seal between the secondary supply passage 38 and the secondary pressure chamber 68 when the secondary piston 19 positions the port 60 on the cylinder bottom side of the piston seal 35. It has become. That is, the piston seal 35 can be sealed by blocking communication between the secondary pressure chamber 68 and the secondary supply path 38 and the reservoir 12. In this sealed state, the secondary piston 19 slides on the sliding inner diameter portion 28 of the cylinder body 15 and the inner periphery of the piston seal 35 and the partition seal 42 held by the cylinder body 15 and moves to the cylinder bottom side. The brake fluid in the secondary pressure chamber 68 is pressurized. The brake fluid pressurized in the secondary pressure chamber 68 is supplied from the secondary discharge passage 26 to the brake cylinder on the wheel side.

When there is no input from the output shaft of a brake booster (not shown) and the secondary piston 19 is in a basic position (non-braking position) where the port 60 is opened to the secondary supply path 38 as shown in FIG. In the recess 59 of the secondary piston 19, a part of the port 60 overlaps in the cylinder axial direction. When the secondary piston 19 moves to the cylinder bottom side of the cylinder body 15 and the inner peripheral portion of the piston seal 35 is completely overlapped with the port 60, the communication between the secondary pressure chamber 68 and the reservoir 12 is blocked.

The primary piston 18 disposed on the cylinder opening side of the cylinder body 15 includes a first cylindrical portion 71, a bottom portion 72 formed on one side in the axial direction of the first cylindrical portion 71, and a first cylinder of the bottom portion 72. The shape which has the 2nd cylindrical part 73 formed in the opposite side to the shape part 71 is comprised. The inner peripheral hole 21 is formed by the first cylindrical portion 71 and the bottom portion 72 among them. The primary piston 18 has the first cylindrical portion 71 disposed on the secondary piston 19 side in the cylinder body 15 and each of the piston seal 45 and the partition seal 52 provided on the sliding inner diameter portion 29 of the cylinder body 15. The inner periphery is slidably fitted. Here, an output shaft of a brake booster (not shown) is inserted inside the second cylindrical portion 73. By this output shaft, the bottom 72 is pressed toward the bottom of the cylinder.

In the outer peripheral portion on the end side opposite to the bottom 72 of the first cylindrical portion 71, an annular concave portion 75 that is recessed radially inward from the largest outer diameter surface 18 a having the largest diameter on the outer peripheral surface 18 z of the primary piston 18. Is formed. The recess 75 is formed with a plurality of ports 76 penetrating in the radial direction on the bottom 72 side so as to be radially arranged at equal intervals in the cylinder circumferential direction.

Between the secondary piston 19 and the primary piston 18, there is provided an interval adjusting portion 79 including a primary piston spring 78 that determines these intervals in a non-braking state without input from an output shaft of a brake booster (not shown). The gap adjusting portion 79 includes a locking member 81 that contacts the bottom 72 of the primary piston 18, a locking member 82 that contacts the bottom 56 of the secondary piston 19, and one end fixed to the locking member 81. And a shaft member 83 that slidably supports the stop member 82 only within a predetermined range. The primary piston spring 78 is interposed between the locking member 81 and the locking member 82.

A portion of the cylinder body 15 surrounded by the cylindrical portion 14, the primary piston 18 and the secondary piston 19 generates a primary pressure chamber 85 (pressure chamber) that generates brake fluid pressure and supplies brake fluid to the primary discharge passage 27. ). In other words, the primary piston 18 forms a primary pressure chamber 85 that supplies hydraulic pressure to the primary discharge passage 27 between the secondary piston 19 and the cylinder body 15. The primary pressure chamber 85 communicates with the primary supply path 48, that is, the reservoir 12 when the primary piston 18 is in a position to open the port 76 to the primary supply path 48.

The partition seal 52 arranged and held in the circumferential groove 33 of the cylinder body 15 is an integrally molded product made of synthetic rubber. The section seal 52 has a C-shape in which one side of the cross section on the surface including the center line is open to the cylinder bottom side. The partition seal 52 is in sliding contact with the outer peripheral surface 18z of the primary piston 18 moving in the cylinder axial direction, and the outer periphery is in contact with the peripheral groove 33 of the cylinder body 15. Thereby, the partition seal 52 always seals the gap between the primary piston 18 and the position of the partition seal 52 of the cylinder body 15. The partition seal 52 defines the primary supply path 48 and the outside of the cylinder body 15, that is, the outside of the master cylinder 11.

The piston seal 45 disposed and held in the circumferential groove 32 of the cylinder body 15 is an integrally molded product made of synthetic rubber. The piston seal 45 has a C-shape in which one side of the cross section on the surface including the center line is open to the cylinder bottom side. The inner periphery of the piston seal 45 is in sliding contact with the outer peripheral surface 18z of the primary piston 18 that moves in the cylinder axial direction. The outer periphery of the piston seal 45 abuts on the circumferential groove 32 of the cylinder body 15. The piston seal 45 provided in the circumferential groove 32 can seal between the primary supply passage 48 and the primary pressure chamber 85 when the primary piston 18 has the port 76 positioned on the cylinder bottom side of the piston seal 45. is there. That is, the piston seal 45 can be sealed by blocking communication between the primary pressure chamber 85 and the primary supply path 48 and the reservoir 12. In this sealed state, the primary piston 18 slides on the sliding inner diameter portion 29 of the cylinder body 15 and the inner periphery of the piston seal 45 and the partition seal 52 held by the cylinder body 15 and moves to the cylinder bottom side. The brake fluid in the primary pressure chamber 85 is pressurized. The brake fluid pressurized in the primary pressure chamber 85 is supplied from the primary discharge path 27 to the brake cylinder on the wheel side.

When there is no input from the output shaft of a brake booster (not shown), and the primary piston 18 is in a basic position (non-braking position) that opens the port 76 to the primary supply path 48 as shown in FIG. In the recess 75 of the primary piston 18, a part of the port 76 overlaps in the cylinder axial direction. Then, when the primary piston 18 moves to the cylinder bottom side of the cylinder body 15 and the inner peripheral portion of the piston seal 45 completely overlaps the port 76, the communication between the primary pressure chamber 85 and the reservoir 12 is blocked.

As shown in FIG. 2, the circumferential groove 33 that is recessed outward in the cylinder radial direction from the opening-side inner diameter surface 16a and the minimum inner diameter surface 29a is a groove opening 87 (opening) at the position of the opening-side inner diameter surface 16a and the minimum inner diameter surface 29a. have. The circumferential groove 33 has a groove bottom 88 on the inner side in the recess direction, that is, on the outer side in the cylinder radial direction. Further, the circumferential groove 33 has a wall portion 89 that spreads inwardly in the cylinder radial direction from the end portion of the groove bottom 88 on the cylinder opening side. Further, the circumferential groove 33 has a wall portion 90 that extends inwardly in the cylinder radial direction from an end edge portion of the groove bottom 88 on the cylinder bottom side. The groove bottom 88, the wall 89, and the wall 90 are formed in the cylinder body 15 itself. The groove bottom 88, the wall 89 and the wall 90 are formed by cutting the cylinder body 15.

The groove bottom 88 has a groove bottom surface portion 88a. The groove bottom surface portion 88a is a cylindrical surface centered on the cylinder axis, and the length in the cylinder axis direction is constant over the entire circumference in the cylinder circumferential direction.

The wall 89 on the cylinder opening side of the circumferential groove 33 has a wall surface 89a. The wall surface portion 89a extends inward in the cylinder radial direction from the cylinder opening side of the groove bottom 88. The wall surface portion 89a is a flat surface parallel to the orthogonal surface of the cylinder axis. The wall surface portion 89a has a constant inner diameter, a constant outer diameter, and a constant width in the cylinder radial direction over the entire circumference in the cylinder circumferential direction, and has an annular shape centering on the cylinder shaft. The edge on the large diameter side of the wall surface 89a and the edge on the cylinder opening side of the groove bottom 88a are connected by an R chamfer 89b.

The wall portion 90 on the cylinder bottom side of the circumferential groove 33 faces the wall portion 89 in the cylinder axial direction. The wall part 90 has a wall surface part 90a and a slope part 90b. The wall surface portion 90a extends inward in the cylinder radial direction from the cylinder bottom side of the groove bottom 88. The wall surface portion 90a is a flat surface parallel to the orthogonal surface of the cylinder axis. The wall surface portion 90a has a constant inner diameter, a constant outer diameter, and a constant width in the cylinder radial direction over the entire circumference in the cylinder circumferential direction, and has an annular shape centering on the cylinder axis.

The inclined surface portion 90b extends from the inner end edge of the wall surface portion 90a in the cylinder radial direction inwardly in the cylinder radial direction so as to be inclined with respect to the cylinder radial direction so as to be located on the cylinder bottom side toward the inner side in the cylinder radial direction. Yes. In other words, the inclined surface portion 90b extends from the inner end edge portion of the wall surface portion 90a in the cylinder radial direction to the cylinder bottom side so as to decrease in diameter toward the cylinder bottom side. The inclined surface portion 90b has a constant inner diameter, a constant outer diameter, a constant width in the cylinder radial direction, and a constant length in the cylinder axial direction over the entire circumference in the cylinder circumferential direction.

The edge on the large diameter side of the wall surface portion 90a and the edge on the cylinder bottom side of the groove bottom surface portion 88a are connected by an R chamfer 90c. The edge portion on the small diameter side of the slope portion 90b and the minimum inner diameter surface 29a of the sliding inner diameter portion 29 are connected by an R chamfer 90d. The circumferential groove 33 is inclined with respect to the cylinder radial direction so that the sloped portion 90b on the groove opening 87 side of the wall portion 90 on the cylinder bottom side increases in diameter toward the cylinder opening side in the cylinder axial direction.

The partition seal 52 disposed in the circumferential groove 33 has a base 101, an inner peripheral lip 102, and an outer peripheral lip 103. The base 101 is disposed on the cylinder opening side of the partition seal 52. The base 101 has an annular plate shape parallel to the axis orthogonal plane of the partition seal 52. The inner peripheral lip 102 has an annular cylindrical shape that protrudes from the inner peripheral edge of the base 101 toward the cylinder bottom along the cylinder axial direction. The outer peripheral lip 103 has an annular cylindrical shape that protrudes from the outer peripheral edge of the base 101 toward the cylinder bottom along the cylinder axial direction.

The section seal 52 has a cross-sectional one-side shape on a plane including the center line in a natural state before being assembled in the master cylinder 11 as shown in FIG. Here, first, the partition seal 52 in the natural state will be described with reference to FIGS.

As shown in FIG. 3, the base 101 has an end surface 101 a opposite to the inner peripheral lip 102 and the outer peripheral lip 103 having a substantially flat shape, a constant inner diameter, a constant outer diameter, and a constant width in the radial direction. It has an annular shape. The base 101 includes a cylindrical outer peripheral surface 101b, an R chamfer 101c connecting the outer peripheral edge of the end surface 101a and the outer peripheral surface 101b, a cylindrical inner peripheral surface 101d, and an inner peripheral edge of the end surface 101a. R chamfer 101e that connects the portion and the inner peripheral surface 101d.

On the radially outer side of the inner peripheral lip portion 102, a tapered proximal end outer peripheral surface 102a is formed on the axial base portion 101 side, and a cylindrical surface distal end side is opposite to the base portion 101 of the proximal end outer peripheral surface 102a. Each outer peripheral surface 102b is formed. The proximal outer peripheral surface 102a has a smaller diameter as it is separated from the base 101 in the axial direction.

On the radially inner side of the inner peripheral lip 102, the inner end of the tapered base end extending from the end edge of the inner peripheral surface 101 d of the base 101 opposite to the R chamfer 101 e on the base 101 side in the axial direction. A peripheral surface 102c is formed. A tapered intermediate inner peripheral surface 102d is formed on the inner side in the radial direction of the inner peripheral lip portion 102 on the side opposite to the base 101 of the base end side inner peripheral surface 102c. On the opposite side, a cylindrical surface-like tip side inner peripheral surface 102e is formed. The proximal end inner peripheral surface 102c has a smaller diameter as it is separated from the base 101 in the axial direction. 102 d of intermediate | middle inner peripheral surfaces are large diameter, so that it leaves | separates from the base 101 to an axial direction.

On the side opposite to the base 101 of the inner peripheral lip 102, an end edge on the side opposite to the base 101 of the front end side outer peripheral surface 102b and an end edge on the side opposite to the base 101 of the front end inner peripheral surface 102e 102f is formed by connecting the two. The front end face 102f has a substantially flat shape, and has a constant inner diameter and a constant outer diameter and a constant width in the radial direction.

The distal end portion 111 including the entire distal end surface 102f, the distal end side outer peripheral surface 102b and the distal end side inner peripheral surface 102e of the inner peripheral lip portion 102 has a passage communicating the inner peripheral side and the outer peripheral side of the inner peripheral lip portion 102. A plurality of radial grooves 112 (passages) are formed at intervals in the circumferential direction. Specifically, four radial grooves 112 are formed at equal intervals in the circumferential direction of the inner peripheral lip portion 102 as shown in FIG. As shown in FIG. 3, the radial groove 112 continuously opens to the distal end side outer peripheral surface 102b, the distal end surface 102f, and the distal end side inner peripheral surface 102e, and crosses the distal end surface 102f in the radial direction.

A tapered base end inner peripheral surface 103a is formed on the axial base portion 101 side on the radially inner side of the outer peripheral lip portion 103, and a cylinder is formed on the side opposite to the base portion 101 of the base end inner peripheral surface 103a. A planar tip-side inner peripheral surface 103b is formed. The proximal end inner circumferential surface 103a has a larger diameter as it is separated from the base 101 in the axial direction.

On the outer side in the radial direction of the outer peripheral lip 103, on the base 101 side in the axial direction, a tapered base outer peripheral surface 103c extending from the end edge of the outer peripheral surface 101b of the base 101 opposite to the R chamfer 101c. Is formed. Further, on the outer side in the radial direction of the outer peripheral lip 103, a tapered distal outer peripheral surface 103d is formed on the side opposite to the base 101 of the proximal outer peripheral surface 103c. The proximal outer peripheral surface 103c has a larger diameter as it is separated from the base 101 in the axial direction. The distal outer circumferential surface 103d has a smaller diameter as it is separated from the proximal outer circumferential surface 103c in the axial direction.

On the side opposite to the base 101 of the outer peripheral lip 103, there is an end edge on the side opposite to the base 101 of the tip side inner peripheral surface 103b and an end edge on the side opposite to the base 101 of the tip side outer peripheral surface 103d. A leading end surface 103e is formed by tying. The distal end surface 103e has a substantially flat shape, and has a constant inner diameter, a constant outer diameter, and a constant width in the radial direction.

The distal end portion 121 including the entire distal end surface 103e, distal end side inner peripheral surface 103b, and distal end side outer peripheral surface 103d of the outer peripheral lip portion 103 has a diameter serving as a passage communicating the inner peripheral side and the outer peripheral side of the outer peripheral lip portion 103. A plurality of directional grooves 122 (passages) are formed at intervals in the circumferential direction. Specifically, four radial grooves 122 are formed at equal intervals in the circumferential direction of the outer peripheral lip 103 as shown in FIG. That is, the number of radial grooves 122 of the outer peripheral lip 103 is the same as the number of radial grooves 112 of the inner peripheral lip 102. As shown in FIG. 3, the radial groove 122 opens continuously to the distal end inner peripheral surface 103b, the distal end surface 103e, and the distal end side outer peripheral surface 103d, and crosses the distal end surface 103e in the radial direction.

As shown in FIG. 4, each of the plurality of radial grooves 122 is in one-to-one correspondence with the radial groove 112 of the inner peripheral lip portion 102 and matches the circumferential position, that is, the phase of the partition seal 52. In other words, the partition seal 52 has a circumferential position of the radial groove 112 formed at the distal end portion 111 of the inner peripheral lip portion 102 and a circumferential direction of the radial groove 122 formed at the distal end portion 121 of the outer peripheral lip portion 103. The position overlaps.

A partition seal 52 having the above shape in a natural state is disposed in the circumferential groove 33 as shown in FIG. 2, and the primary piston 18 is fitted inside the partition seal 52. In this state, in the partition seal 52, the outer peripheral lip portion 103 abuts against the groove bottom surface portion 88a of the groove bottom 88 with a margin, and the inner peripheral lip portion 102 is the maximum outer diameter surface 18a of the outer peripheral surface 18z of the primary piston 18. Fit with a tight margin. In this state, the partition seal 52 comes into contact with the groove bottom surface 88a of the circumferential groove 33 at the outer peripheral surface 101b of the base 101 and the proximal end outer peripheral surface 103c of the outer peripheral lip 103, and the outer peripheral surface of the distal end side of the outer peripheral lip 103 103 d extends away from the groove bottom surface portion 88 a of the circumferential groove 33 in the radial direction toward the side opposite to the base portion 101. In this state, the partition seal 52 basically abuts the outer peripheral surface 18z of the primary piston 18 at the proximal inner peripheral surface 102c and the intermediate inner peripheral surface 102d of the inner peripheral lip portion 102, so The peripheral surface 102e is separated from the outer peripheral surface 18z of the primary piston 18 in the radial direction. Further, in this state, in the partition seal 52, the front end side inner peripheral surface 103b of the outer peripheral lip portion 103 and the front end side outer peripheral surface 102b of the inner peripheral lip portion 102 are separated in the radial direction.

In the partition seal 52 configured as described above, the inner peripheral lip portion 102 is in sliding contact with the outer peripheral surface 18 z of the primary piston 18, and the outer peripheral lip portion 103 is in contact with the groove bottom surface portion 88 a of the peripheral groove 33 of the cylinder body 15.

The circumferential groove 33 is in the cylinder radial direction, that is, in the radial direction of the primary piston 18 so that the sloped portion 90b on the groove opening 87 side of the wall portion 90 on the cylinder bottom side increases in diameter as it approaches the partition seal 52 in the cylinder axial direction. It is inclined with respect to. Further, the circumferential groove 33 has a wall surface portion 90a on the groove bottom 88 side of the wall portion 90 that faces the outer circumferential lip portion 103 of the partition seal 52 in the radial direction so as to face the axial direction. The portion 90b is opposed to the inner circumferential lip portion 102 of the partition seal 52 in the axial direction with the radial position overlapped.

FIG. 1 shows a basic state (non-braking state before the brake pedal is operated) of the master cylinder 11 in which there is no input from the output shaft side of a brake booster (not shown). When in this basic state, the primary piston 18 allows the port 76 to communicate with the primary supply path 48. The secondary piston 19 makes the port 60 communicate with the secondary supply path 38.

During braking, when there is an input from the output shaft side of a brake booster (not shown) and the primary piston 18 moves from the basic state to the cylinder bottom side, the port 76 is closed by the piston seal 45, and the primary pressure chamber 85 and Communication with the primary supply path 48 is blocked. As a result, as the primary piston 18 moves toward the cylinder bottom side, the hydraulic pressure in the primary pressure chamber 85 rises and the brake fluid in the primary pressure chamber 85 is supplied from the primary discharge path 27 to the brake cylinder on the wheel side. The In parallel with this, the secondary piston 19 is pressed by the primary piston 18 via the interval adjusting portion 79 and moved from the basic state to the cylinder bottom side, and the port 60 is closed by the piston seal 35, and the secondary piston 19 is closed. The communication between the pressure chamber 68 and the secondary supply path 38 is blocked. As a result, as the secondary piston 19 moves to the cylinder bottom side, the hydraulic pressure in the secondary pressure chamber 68 rises and the brake fluid in the secondary pressure chamber 68 is supplied from the secondary discharge passage 26 to the brake cylinder on the wheel side. The

The master cylinder described in Patent Document 1 described above is provided with a seal in the circumferential groove of the cylinder body for defining a replenishment path communicating with the reservoir and the outside of the cylinder body. The seal has a C-shaped one-sided cross section on the surface including the center line, and slidably contacts the primary piston at the inner peripheral lip portion and contacts the peripheral groove of the cylinder body at the outer peripheral lip portion.

In the master cylinder 11 of the first embodiment, the sealability of each part is inspected in the assembled state, but the sealability of the partition seal 52 is also inspected. In this case, for example, evacuation is performed from either one of the primary replenishment path 48 and the primary discharge path 27 while the other is closed. Then, if the inside of the primary pressure chamber 85 is in a predetermined negative pressure state, for example, a state in which a pressure equal to or lower than a predetermined value is maintained for a predetermined time, it is determined that the sealing performance of the partition seal 52 is good, and the predetermined negative pressure state is reached. If not, it is determined that the sealing performance of the partition seal 52 is poor.

Here, as a cause of the poor sealing performance of the partition seal 52, foreign matter F is mixed between the groove bottom 88 of the circumferential groove 33 and the outer peripheral lip 103 of the partition seal 52 as shown in FIG. . The foreign matter F is, for example, chips generated when the cylinder body 15 is cut. The foreign matter F mixed in this way forms a gap where the outer peripheral lip 103 of the partition seal 52 and the groove bottom 88 do not adhere to each other at least on both sides of the foreign matter F in the circumferential direction of the circumferential groove 33 and the partition seal 52. Therefore, at the time of inspection, air flows from the opening 16 side of the cylinder body 15 to the evacuated primary pressure chamber 85 through this gap, and the primary pressure chamber 85 does not enter a predetermined negative pressure state. By detecting this, it is possible to detect a poor sealing performance of the partition seal 52.

At the time of evacuation, the partition seal 52 is sucked toward the primary replenishment path 48 and moves to the wall 90 side in the circumferential groove 33 as shown in FIG. It may abut against the portion 90a. In such a state, as shown in FIG. 6, the front end 121 ′ of the outer peripheral lip 103 ′ is not formed with a passage that connects the inner peripheral side and the outer peripheral side of the outer peripheral lip 103 ′. With the partition seal 52 ′, the tip 121 ′ of the outer peripheral lip 103 ′ can be in close contact with the wall surface 90a of the wall 90 over the entire circumference. In this case, even if a gap is formed between the outer peripheral lip portion 103 ′ of the partition seal 52 ′ and the groove bottom 88 by the foreign matter F, the outer peripheral lip on the primary replenishment path 48 side, which is upstream from this. The tip portion 121 ′ of the portion 103 ′ seals between the wall portion 90 and the entire circumference, so that no air flows into the primary supply path 48 side. As a result, there is a possibility that the primary supply path 48 side is in a predetermined negative pressure state and is determined to be normal.

On the other hand, in the first embodiment, as shown in FIG. 5, the radial direction becomes a passage that communicates the inner peripheral side and the outer peripheral side of the outer peripheral lip 103 with the tip 121 of the outer peripheral lip 103 of the partition seal 52. A groove 122 is formed. Therefore, even if the partition seal 52 is sucked to the primary supply path 48 side and moves to the wall 90 side in the circumferential groove 33, the outer peripheral lip 103 may come into contact with the wall surface 90 a of the wall 90. The radial groove 122 is connected to the groove bottom 88 side and the groove opening 87 side of the front end portion 121 by suppressing the sealing between the front end portion 121 and the wall portion 90 of the outer peripheral lip portion 103 over the entire circumference. Let

In the first embodiment, a radial groove 112 serving as a passage communicating the inner peripheral side and the outer peripheral side of the inner peripheral lip portion 102 is also formed at the tip 111 of the inner peripheral lip portion 102 of the partition seal 52. Yes. Therefore, even if the partition seal 52 is sucked to the primary supply path 48 side and moves to the wall 90 side in the circumferential groove 33, the inner peripheral lip 102 may come into contact with the inclined surface 90b of the wall 90, The radial groove 112 is prevented from sealing between the tip portion 111 of the inner peripheral lip portion 102 and the wall portion 90 over the entire circumference, and the groove bottom 88 side and the groove opening 87 side of the tip portion 111 are connected to each other. Communicate.

As described above, when foreign matter F is mixed between the groove bottom 88 of the circumferential groove 33 and the outer peripheral lip 103 of the partition seal 52, the base 101 and the wall 89 are formed from the opening 16 of the cylinder body 15. The primary replenishment path 48 is formed through the gap, the gap between the outer peripheral lip 103 and the groove bottom 88 due to the foreign matter F, the gap between the wall 90 and the radial groove 122, and the gap between the wall 90 and the radial groove 112. Air flows to the side, and the negative pressure state on the primary supply path 48 side is brought close to atmospheric pressure. Thereby, mixing of the foreign material F between the groove bottom 88 and the outer peripheral lip 103 can be detected well. Therefore, a product in which the foreign matter F is mixed between the groove bottom 88 and the outer peripheral lip 103 can be well eliminated. For this reason, the quality of the master cylinder 11 can be improved.

The radial groove 122 is formed in the front-end | tip part 121 of the outer peripheral lip part 103 as a channel | path which connects the inner peripheral side of the outer peripheral lip part 103 of the division seal 52, and an outer peripheral side. For this reason, the radial groove 122 can be easily formed when the partition seal 52 is integrally formed, and the manufacture of the partition seal 52 is facilitated.

The circumferential groove 33 is inclined with respect to the radial direction of the primary piston 18 so that the groove opening 87 side of the wall portion 90 on the cylinder bottom side increases in diameter as it approaches the partition seal 52. For this reason, even if the partition seal 52 is sucked toward the primary supply path 48 and moves toward the wall portion 90 in the circumferential groove 33, the inner peripheral lip portion 102 can hardly be brought into contact with the inclined surface portion 90 b of the wall portion 90.

The partition seal 52 includes a circumferential position of the radial groove 112 as a passage formed in the distal end portion 111 of the inner peripheral lip portion 102 and a radial groove 122 as a passage formed in the distal end portion 121 of the outer peripheral lip portion 103. The position in the circumferential direction overlaps. For this reason, when the partition seal 52 is sucked toward the primary supply path 48 and moved to the wall 90 side in the circumferential groove 33, the distal end portion 111 of the inner peripheral lip portion 102 and the distal end portion 121 of the outer peripheral lip portion 103 Even if they come into contact with each other, it is possible to prevent the communication between the radial groove 112 and the radial groove 122 from being blocked. Therefore, it can further be suppressed that the space between the partition seal 52 and the wall 90 is in a sealed state over the entire circumference.

Note that the radial groove 122 is set to a size that allows communication between the inner peripheral side and the outer peripheral side of the outer peripheral lip 103 even when the outer peripheral lip 103 is deformed to the maximum in the peripheral groove 33. Similarly, the radial groove 112 is set to a size that allows communication between the inner peripheral side and the outer peripheral side of the inner peripheral lip 102 even when the inner peripheral lip 102 is deformed to the maximum in the peripheral groove 33.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described mainly with reference to FIG. 7 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.

The second embodiment has a partition seal 52A that is partially different from the partition seal 52 of the first embodiment. Unlike the inner peripheral lip portion 102 in which the radial groove 112 of the first embodiment is formed in the distal end portion 111, the partition seal 52A has an inner peripheral lip portion 102A having a distal end portion 111A in which the radial groove 112 is not formed. It has.

Further, the second embodiment has a cylinder body 15A that is partially different from the cylinder body 15 of the first embodiment. The cylinder main body 15A according to the second embodiment has an outer portion in the cylinder radial direction than the minimum inner diameter surface 29a at a portion between the circumferential groove 33 and the opening groove 47 with respect to the sliding inner diameter portion 29 of the first embodiment. It has a sliding inner diameter portion 29A which is different in that a recess 151A is formed. The recess 151A allows the circumferential groove 33 and the opening groove 47 to communicate with each other in the cylinder axial direction, and crosses the inclined surface portion 90b of the circumferential groove 33 in the cylinder radial direction.

In the second embodiment, a radial groove 122 serving as a passage communicating the inner peripheral side and the outer peripheral side of the outer peripheral lip 103 is formed at the tip 121 of the outer peripheral lip 103 of the partition seal 52A, as in the first embodiment. Is formed. Therefore, even if the partition seal 52A is sucked toward the primary supply path 48 and moves to the wall 90 side in the circumferential groove 33, the outer peripheral lip 103 may come into contact with the wall surface 90a of the wall 90. The radial groove 122 regulates that the space between the tip portion 121 of the outer peripheral lip 103 and the wall portion 90 is in a sealed state over the entire circumference, and communicates the groove bottom 88 side and the groove opening 87 side of the tip portion 121. Let

In the second embodiment, the partition seal 52A is sucked toward the primary supply path 48 and moved toward the wall 90 in the circumferential groove 33 so that the inner peripheral lip 102A abuts against the inclined surface 90b of the wall 90. Even if this happens, the recess 151A regulates that the space between the tip portion 111A of the inner peripheral lip portion 102A and the wall portion 90 is sealed over the entire circumference, and the groove bottom 88 side of the tip portion 111A and the groove The opening 87 side is connected.

As described above, according to the second embodiment, as in the first embodiment, when foreign matter F is mixed between the groove bottom 88 of the circumferential groove 33 and the outer peripheral lip 103 of the partition seal 52A, the cylinder body 15 From the opening 16, the gap between the base 101 and the wall 89, the gap between the outer peripheral lip 103 and the groove bottom 88 due to the foreign matter F, the gap between the wall 90 and the radial groove 122, and the recess 151A and the tip Air flows to the primary supply path 48 side through the gap with 111A, and the negative pressure state on the primary supply path 48 side is brought close to atmospheric pressure. Thereby, mixing of the foreign material F between the groove bottom 88 and the outer peripheral lip 103 can be detected well.

Note that the recess 151A is set to a size that allows communication between the inner peripheral side and the outer peripheral side of the inner peripheral lip 102A even when the inner peripheral lip 102A is deformed to the maximum in the peripheral groove 33.

[Third Embodiment]
Next, a third embodiment according to the present invention will be described mainly on the difference from the first embodiment based on FIG. In addition, about the site | part which is common in 1st Embodiment, it represents with the same name and the same code | symbol.

The third embodiment has a partition seal 52B that is partially different from the partition seal 52 of the first embodiment. Unlike the outer peripheral lip portion 103 in which the radial groove 122 is formed in the distal end portion 121 of the first embodiment, the partition seal 52B does not have the radial groove 122 formed therein. The partition seal 52B includes an outer peripheral lip 103B in which a radial hole 122B (passage) is formed at the tip 121B. A plurality of radial holes 122B are formed at intervals in the circumferential direction of the outer peripheral lip 103B. The radial hole 122B opens to the distal end side outer peripheral surface 103d and the distal end side inner peripheral surface 103b, and does not open to the distal end surface 103e. The radial hole 122B serves as a passage that connects the inner peripheral side and the outer peripheral side of the outer peripheral lip 103B.

Unlike the inner peripheral lip portion 102 in which the radial groove 112 is formed in the distal end portion 111 of the first embodiment, the partition seal 52B does not have the radial groove 112 formed therein. The partition seal 52B includes an inner peripheral lip portion 102B in which a radial hole 112B (passage) is formed in the distal end portion 111B. A plurality of radial holes 112B are formed at intervals in the circumferential direction of the inner peripheral lip portion 102B. The radial hole 112B opens in the distal end side outer peripheral surface 102b and the distal end side inner peripheral surface 102e, and does not open in the distal end surface 102f. The radial hole 112B serves as a passage that connects the inner peripheral side and the outer peripheral side of the inner peripheral lip portion 102B.

The plurality of radial holes 122B are in one-to-one correspondence with the radial holes 112B of the inner peripheral lip portion 102B, and the circumferential positions of the partition seals 52B, that is, the phases are matched. In other words, the partition seal 52B is positioned in the circumferential direction of the radial hole 112B formed in the distal end portion 111B of the inner peripheral lip portion 102B and in the circumferential direction of the radial hole 122B formed in the distal end portion 121B of the outer peripheral lip portion 103B. The position overlaps.

In the third embodiment, a radial hole 122B serving as a passage communicating the inner peripheral side and the outer peripheral side of the outer peripheral lip 103B is formed in the tip 121B of the outer peripheral lip 103B of the partition seal 52B. Therefore, the partition seal 52B is sucked toward the primary supply path 48 and moves to the wall 90 side in the circumferential groove 33 as shown in FIG. 8 so that the outer peripheral lip 103B contacts the wall 90a of the wall 90. Even if this occurs, the radial hole 122B allows the groove bottom 88 side and the groove opening 87 side of the tip 121B to communicate with each other.

In the third embodiment, a radial hole 112B serving as a passage communicating the inner peripheral side and the outer peripheral side of the inner peripheral lip portion 102B is also formed at the tip 111B of the inner peripheral lip portion 102B of the partition seal 52B. ing. Therefore, even if the partition seal 52B is sucked toward the primary supply path 48 and moves toward the wall 90 in the circumferential groove 33, the inner peripheral lip 102B may come into contact with the inclined surface 90b of the wall 90. The radial hole 112B allows the groove bottom 88 side and the groove opening 87 side of the tip end portion 111B to communicate with each other.

As described above, according to the third embodiment, as in the first embodiment, when foreign matter F is mixed between the groove bottom 88 of the circumferential groove 33 and the outer peripheral lip 103B of the partition seal 52B, the cylinder body 15 Primary replenishment path 48 through the gap 16 between the base 101 and the wall 89, the gap between the outer peripheral lip 103B and the groove bottom 88 due to the foreign matter F, the radial hole 122B, and the radial hole 112B. Air flows to the side, and the negative pressure state on the primary supply path 48 side is brought close to atmospheric pressure. Thereby, mixing of the foreign material F between the groove bottom 88 and the outer peripheral lip 103B can be detected well.

As a passage that connects the inner peripheral side and the outer peripheral side of the outer peripheral lip 103B of the partition seal 52B, a radial hole 122B is formed in the tip 121B of the outer peripheral lip 103B. For this reason, the durability fall of the front-end | tip part 121B can be suppressed.

As a passage that connects the inner peripheral side and the outer peripheral side of the inner peripheral lip portion 102B of the partition seal 52B, a radial hole 112B is formed in the tip portion 111B of the inner peripheral lip portion 102B. For this reason, the durability fall of the front-end | tip part 111B can be suppressed.

The partition seal 52B includes a circumferential position of a radial hole 112B as a passage formed in the distal end portion 111B of the inner peripheral lip portion 102B and a radial hole 122B as a passage formed in the distal end portion 121B of the outer peripheral lip portion 103B. The position in the circumferential direction overlaps. For this reason, when the partition seal 52B is sucked to the primary supply path 48 side and moved to the wall 90 side in the circumferential groove 33, the distal end portion 111B of the inner peripheral lip portion 102B and the distal end portion 121B of the outer peripheral lip portion 103B Even if they come into contact with each other, it is possible to prevent the communication between the radial hole 112B and the radial hole 122B from being blocked.

It should be noted that the radial hole 122B is set to a size that allows communication between the inner peripheral side and the outer peripheral side of the tip 121B even when the outer peripheral lip 103B is deformed to the maximum in the peripheral groove 33. Similarly, the radial hole 112B is set to a size that allows communication between the inner peripheral side and the outer peripheral side of the distal end portion 111B even when the inner peripheral lip portion 102B is deformed to the maximum in the peripheral groove 33.

Here, a partition seal having an outer peripheral lip portion 103B having a radial hole 122B in the distal end portion 121B of the third embodiment and an inner peripheral lip portion 102A having no passage in the distal end portion 111A of the second embodiment, You may combine with cylinder main body 15A which has recess 151A of embodiment. Further, as a partition seal having an outer peripheral lip portion 103B having a radial hole 122B in the distal end portion 121B of the third embodiment and an inner peripheral lip portion 102 having a radial groove 112 in the distal end portion 111 of the first embodiment. good. Further, as a partition seal having an inner peripheral lip portion 102B having a radial hole 112B in the distal end portion 111B of the third embodiment and an outer peripheral lip portion 103 having a radial groove 122 in the distal end portion 121 of the first embodiment. good.

According to the first aspect of the above embodiment, the master cylinder has a bottomed cylindrical cylinder body having a brake fluid discharge path and a supply path communicating with the reservoir, and is movably disposed in the cylinder body. And a piston that forms a pressure chamber that supplies hydraulic pressure to the discharge passage between the cylinder body and a circumferential groove that opens to the inner circumferential surface of the cylinder body, Includes a seal that is in sliding contact with the piston to define the replenishment path and the outside of the cylinder body. The seal includes an inner peripheral lip portion that protrudes from an annular base portion and slidably contacts the outer peripheral surface of the piston, and an outer peripheral lip portion that contacts the peripheral groove of the cylinder body. The outer peripheral lip portion is formed with a passage communicating with the inner peripheral side and the outer peripheral side of the outer peripheral lip portion at the distal end portion. As a result, it is possible to satisfactorily detect the mixing of foreign matter between the groove bottom of the peripheral groove and the outer peripheral lip portion, and the quality can be improved.

A second aspect is the above-described first aspect, wherein the passage of the outer peripheral lip portion is a radial groove formed at a tip portion.

In a third aspect according to the first aspect, the passage of the outer peripheral lip portion is a radial hole.

According to a fourth aspect, in any one of the first to third aspects, the circumferential groove has a diameter that increases as the opening side of the wall portion on the bottom side of the cylinder main body approaches the seal. It is inclined with respect to the radial direction.

In a fifth aspect according to any one of the first to third aspects, the inner peripheral lip portion is formed with a passage communicating with an inner peripheral side and an outer peripheral side of the inner peripheral lip portion at a tip portion. Yes.

According to a sixth aspect, in the fifth aspect, the seal is formed in a circumferential position of the passage formed at a distal end portion of the inner peripheral lip portion and the passage formed at a distal end portion of the outer peripheral lip portion. The position in the circumferential direction overlaps.

According to the master cylinder described above, the quality can be improved.

11 Master cylinder 12 Reservoir 15 Cylinder body 15a Inner circumferential surface 18 Primary piston (piston)
27 Primary discharge path (discharge path)
33 Circumferential groove 48 Primary supply path (supply path)
52 division seal (seal)
85 Primary pressure chamber (pressure chamber)
87 Groove opening (opening)
90 Wall portion 90b Slope portion 101 Base portion 102 Inner peripheral lip portion 103 Outer peripheral lip portion 111 Tip portion (tip portion of inner peripheral lip portion)
112 radial groove (passage of inner lip)
112B radial hole (passage of inner lip)
121 Tip (tip of outer lip)
122 radial groove (passage of outer lip)
122B radial hole (passage of outer lip)

Claims

A bottomed cylindrical cylinder body having a brake fluid discharge path and a supply path communicating with the reservoir;
A piston which is movably disposed in the cylinder body and forms a pressure chamber between which the fluid pressure is supplied to the discharge passage;
A seal that is disposed in a circumferential groove that is formed by opening in the inner peripheral surface of the cylinder body, the inner circumference slidingly contacts the piston, and defines the supply path and the outside of the cylinder body;
The seal has an inner peripheral lip portion that protrudes from an annular base portion and slidably contacts the outer peripheral surface of the piston, and an outer peripheral lip portion that contacts the peripheral groove of the cylinder body,
The outer peripheral lip portion is formed with a passage communicating with an inner peripheral side and an outer peripheral side of the outer peripheral lip portion at a tip portion.
The master cylinder according to claim 1, wherein the passage of the outer peripheral lip portion is a radial groove formed at a distal end portion.
The master cylinder according to claim 1, wherein the passage of the outer peripheral lip portion is a radial hole.
The circumferential groove is inclined with respect to the radial direction of the piston so that the opening side of the wall portion on the bottom side of the cylinder body increases in diameter as it approaches the seal. The master cylinder described.
The master cylinder according to any one of claims 1 to 3, wherein the inner peripheral lip portion has a leading end formed with a passage communicating the inner peripheral side and the outer peripheral side of the inner peripheral lip portion.
6. The seal includes a circumferential position of the passage formed at a distal end portion of the inner peripheral lip portion and a circumferential position of the passage formed at a distal end portion of the outer peripheral lip portion. Master cylinder.