JPH0623858U - Master cylinder - Google Patents

Abstract

(57) [Summary] [Purpose] Stabilize the initial loss stroke and regulate the retreat limit of the piston. [Structure] A piston 5 is slidably arranged in a cylinder housing 2, and a piston guide 7 and a sleeve 9 are provided.
In the master cylinder 40 guided by, the piston 5 is provided with an engaging portion 41, and the piston 5,
A seal member 28 that seals in one direction is arranged on a surface along the piston guide 8 and the sleeve 9, and a retainer member 42 having a Vokutoku shape is arranged between the engaging portion 41 of the piston 5 and the seal member 28. And make them engageable with each other,
The retreat limit of the piston 5 restricts the retreat of the piston 5 and presses the seal member 28 against the piston guide 7.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a master cylinder used in various braking devices for motor vehicles.

[0002]

[Prior art]

 Conventionally, as this type of master cylinder, for example, there is a tandem master cylinder shown in FIG. The master cylinder 1 is configured as a cylinder housing 2 by a body body 3 made of, for example, an aluminum alloy and a cap 4 having an opening at one end.

The body body 3 has an opening 3a at one end, and a female screw 3b is formed on the inner peripheral surface of the opening 3a. On the other hand, a male screw 4a is formed on the outer peripheral surface of one end of the cap 4, and the cap 4 is attached to the body body 3 by screwing the male screw 4a into the female screw 3b of the body body 3. It

Inside the body 3, a tip portion of a primary piston 5 and a secondary piston 6 are fitted in the cap 4 and slidably disposed via piston guides 7 and 8. Further, inside the body body 3, a first pressure chamber 10 is formed by the primary piston 5 and a resin sleeve 9 for guiding the piston 5, and by the secondary piston 6 and the inner wall surface of the body body 3. The second pressure chamber 11 is formed.

Spring mechanisms 12 and 13 are provided in the first pressure chamber 10 and the second pressure chamber 11, respectively, in order to urge the primary piston 5 and the secondary piston 6 in the backward direction. The spring mechanism 12 includes a return spring 14, a guide screw 15, and a cap-shaped retainer 16. One end of the return spring 14 is held by the bottom surface of the spring holding hole 5a formed in the end face of the primary piston 5, and the other end is held by the peripheral edge of the retainer 16. The guide screw 15 is screwed into the bottom surface of the spring holding hole 5a so as to project from the bottom surface in the piston axial direction by a predetermined length. The retainer 16 has a hole formed in the top of the cap-shaped cap, which freely slides on the guide screw 15 within a predetermined stroke range and engages with the end thereof.

The spring mechanism 13 is composed of a return spring 17, a spring holding guide 18, and a retainer 19 in the shape of a bowl cap, and its function is the same as that of the spring mechanism 12.

As described above, in the master cylinder 1, when the primary piston 5 and the secondary piston 6 are pushed leftward in the drawing into the first pressure chamber 10 and the second pressure chamber 11, respectively, the pressure chamber 10 The hydraulic pressure in the pumps 11 and 11 is increased, and the hydraulic fluid is pumped from the outlets 20 and 21 to a brake system (not shown).

By the way, in the master cylinder 1, the passages through which the primary piston 5 and the secondary piston 6 communicate with the sleeve 9 guided in the cylinder housing 2 and the replenisher liquid passages 23, 24, 25 from the oil reservoir 22, respectively. It is fitted and guided by piston guides 7 and 8 which are provided with 26 and 27, respectively.

In the first pressure chamber 10 on the primary piston 5 side, the brake operation is released on the contact surface between the sleeve 9 and the piston guide 7 and the sliding surface between the piston guide 7 and the primary piston 5. In order to form a liquid replenishment passage when the liquid is supplied, an annular one-way seal member 28 is arranged across this portion. That is, when the break operation is released, the inside of the first pressure chamber 10 becomes a negative pressure, so that the one-way seal member 28 deforms and loses its sealing function, and promotes the replacement liquid from the liquid supply passage. Similarly, an annular one-way seal member 29 is also provided in the second pressure chamber on the secondary piston 6 side.

When the primary piston 5 and the secondary piston 6 are pressed into the first and second pressure chambers 10 and 11, respectively, and the brake is actuated, the hydraulic pressure in the pressure chambers 10 and 11 increases, and The direction sealing members 28, 29 are pressed against their respective sealing surfaces by their hydraulic pressure to seal.

Reference numerals 5b and 6b denote small holes formed in the outer peripheral surfaces of the primary piston 5 and the secondary piston 6, respectively, from the oil reservoir 22 at the brake release position to the first and second pressure chambers 10 and 11. To form a replenisher passage. Further, annular seal members 30, 31a, 31b, 32, 33 are arranged in the cylinder housing 2.

[0012]

[Problems to be solved by the device]

 However, when the primary cylinder 5 and the secondary piston 6 retract and the master cylinder 1 in operation returns to the non-operation state (brake release state), the negative pressure in the first pressure chamber 10 is temporarily reduced. Therefore, the one-way seal member 28 may be deformed so as to be drawn into the pressure chamber 10 and the mounting position may change.

As described above, the positions of the small hole 5b of the primary piston 5 and the one-way seal member 28 are not stable when the master cylinder 1 is not operated. Therefore, at the time of the next operation, the primary piston 5 is pushed into the cylinder housing 2 to close the small hole 5b communicating with the oil reservoir 22 and increase the hydraulic pressure in the first pressure chamber 10. However, there is a problem that the stroke until the one-way seal member 28 is returned to the normal mounting position, that is, the initial loss stroke is not stable. Further, the structure in which the one-way seal member 28 is always held at the proper mounting position hinders proper deformation of the seal member 28 when the primary piston 5 retracts, and a sufficient replenishing liquid flow rate cannot be obtained.

At the same time, there is also a problem that the backward limit of the primary piston 5 must be restricted when the master cylinder 1 is not operating.

The present invention has been made in view of the above problems, and an object thereof is to solve the above-mentioned problems, and to fix the position of a seal member, which is arranged on the pressure chamber side and seals in one direction, in a non-operating state. It is to stabilize the initial loss stroke by stabilizing it at the standard position, and to provide the master cylinder in which the backward limit of the piston is restricted.

[0016]

[Means for Solving the Problems]

 The structure of the present invention for achieving the above object is as follows.

(1) A cylinder housing is constituted by a body main body having an opening at one end and a cap which is coupled to the body main body and closes the opening, and the piston is fitted with the cap to insert the cap. In a master cylinder guided by a piston guide and a sleeve slidably arranged in the cylinder housing and provided with a passage leading to an external fluid passage,

The piston is provided with an engaging portion, and a seal member that seals in one direction is provided on a surface along the piston, the piston guide, and the sleeve, and the engaging portion of the piston and the seal are disposed. Goutoku-shaped retainer members are arranged between the members and allow them to engage with each other, and the retreat limit of the piston restricts the retreat of the piston, and the seal member serves as the piston guide. It is characterized by being pressed.

(2) A cylinder housing is configured by a body body having an opening at one end and a cap that is coupled to the body body and closes the opening, and a piston is inserted into the cylinder to insert the cap into the cylinder. In a master cylinder that is slidably arranged in the housing, is biased in the backward direction by a spring mechanism, and is guided by a piston guide and a sleeve that have a passage communicating with an external fluid passage,

A seal member that seals in one direction is arranged on a surface along the piston, the piston guide, and the sleeve, and the spring mechanism includes a return spring whose one end abuts on the end surface of the piston. , A guide member fixed to the end surface of the piston, and a retainer member in the shape of a mountain hat that slides and engages with the guide member and abuts the other end of the return spring to mount the same. At the same time, a plurality of leg portions are extended in the piston side direction from the peripheral edge portion of the retainer member where the return spring is mounted, and the ends of the retainer member are engageable with the seal member. It is characterized in that the retreat of the piston is restricted and the seal member is pressed against the piston guide.

[0021]

[Action]

 Since the present invention is configured as described above, a Gotoku-shaped retainer member is provided between the engaging portion of the piston and the seal member so that they can be engaged with each other, or By extending a plurality of legs from the peripheral edge of the retainer member that engages with the piston via the guide member and making the ends engageable with the seal member, the piston retracts when not operating. The retreat of the piston is restricted by a limit, and the seal member is pressed against the seal surface to seal.

[0022]

【Example】

 Hereinafter, a preferred embodiment of the present invention will be exemplarily described in detail with reference to the drawings. 1 to 4 are views showing a first embodiment of a master cylinder of the present invention, the same members as those in FIG. 8 are designated by the same reference numerals, and the description thereof will be omitted.

1 to 4, a resin sleeve 9 provided for guiding the primary piston 5 inside a master cylinder 40 has a first pressure chamber 10 and a hydraulic fluid delivery port 20. In order to communicate with each other, a plurality of (9 in the figure) grooves 9a are axially arranged on the inner peripheral surface of the groove 9a evenly along the inner periphery.

A plurality of engaging portions 41 are formed so as to project in the radial direction on the outer peripheral surface of the end portion of the primary piston 5 and can be inserted into the grooves 9 a of the sleeve 9, respectively. At the time of operation, a retainer 42 is provided between the engaging portion 41 and the seal member 28 that seals the pressure chamber 10 in one direction so as to be engageable with each other.

As shown in FIG. 3, the retainer 42 has a shape of Gotoku (a three-legged or four-legged instrument that is placed on a charcoal fire in a brazier and hangs an iron bottle, etc.) on one side, and the seal part The annular portion 42a is formed so as to be engaged with 28, and a plurality of (8 in this embodiment) leg portions 42b are equally spaced from the annular portion 42a on the other side. The primary piston 5 is inclined to stand upright, and an end portion 42c is formed at the tip thereof. Then, these end portions 42c are engaged with the respective engaging portions 41 at the retreat limit of the primary piston 5. The widths of the leg portions 42b and the end portions 42c are such that they can be inserted into the grooves 9a of the sleeve 9.

Since the retainer 42 is normally disposed so as to be engaged with the seal member 28, when the master cylinder 40 is operated, that is, when the primary piston 5 is pushed into the cylinder housing 2. The engaging portion 41 is disengaged from the end portion 42c of the retainer 42 and separated from each other.

Next, when the master cylinder 40 is not in operation, that is, when the primary piston 5 is retracted, and the retracted limit is reached, the engagement portion 41 engages with the end portion 42c of the retainer 42 to cause the primary piston 5 to retract. The piston 5 is restricted from further retracting. At the same time, the seal member 28 is pressed against the piston guide 7 at a regular position from the spring mechanism 12 via the annular portion 42a of the retainer 42.

5 to 7 are views showing a second embodiment of the present invention. The same members as those in FIG. 8 are designated by the same reference numerals and the description thereof will be omitted. 5 to 7, the spring mechanism 51 for urging the primary piston 5 fitted in the master cylinder 50 in the backward direction is similar to the spring mechanism 12 and is similar to the return spring 14. , A guide screw 15 and a modified cap-shaped retainer 52.

One end of the return spring 14 is held on the bottom surface of the spring holding hole 5 a provided on the end face of the primary piston 5, and the other end is held on the peripheral edge portion 52 a of the retainer 52. The guide screw 15 is screwed into the bottom surface of the spring holding hole 5a so as to project from the bottom surface in the piston axial direction by a predetermined length. The retainer 52 has a hole 52b provided at the top of the cap-shaped cap, which freely slides on the guide screw 15 within a predetermined stroke range and engages with the end thereof.

As shown in FIG. 6, the retainer 52 has a plurality of (in this embodiment, eight) leg portions 52c extending from the peripheral edge portion 52a at equal intervals along the peripheral edge portion 52a. On the piston 5 side and in the oblique radial direction, an end portion 52d is formed at the tip thereof. Then, these end portions 52d are engaged with the seal member 28 at the retreat limit of the primary piston 5. The widths of the leg portions 52c and the end portions 52d are such that they can be inserted into the grooves 9a of the sleeve 9.

Since the retainer 52 constitutes the spring mechanism 51 of the primary piston 5, the retainer 52 is pushed in together with the piston 5 when the master cylinder 50 is operated, and the end portion 52 d of the retainer 52 forms a contact with the seal member 28. Disengage and separate from each other.

Next, when the master cylinder 50 is not in operation, the retainer 52 engages with the guide screw 15 fixed to the piston 5 and the end portion 52d of the retainer 52 is in the rearward withdrawal direction of the primary piston 5. By engaging with the seal member 28, the further retraction of the primary piston 5 is restricted. At the same time, the seal member 28 is pressed against the piston guide 7 from the spring mechanism 51 via the end portion 52d of the retainer 52 at a regular position.

In the first and second embodiments, if the initial loss stroke on the secondary piston 6 side is set to be always shorter than the same stroke on the primary piston 5 side, the master cylinder 40 The initial loss stroke of 50 is always stable.

The technique of the present invention is not limited to the technique in the above-mentioned embodiment, and means of another aspect having a similar function may be used. The technique of the present invention is within the scope of the above configuration. Various changes and additions are possible.

[0035]

[Effect of device]

 As is clear from the above description, according to the master cylinder of the present invention, a retainer member having a Gotoku shape is disposed between the engagement portion of the piston and the seal member, and the retainer member is engaged with each of them. By making it possible or by extending a plurality of legs from the peripheral edge of the retainer member that engages with the piston via a guide member and making its ends engageable with the seal member. During operation, the sealing member is pressed against a predetermined sealing surface to seal.

Therefore, when the master cylinder 1 is not in operation, the position of the seal member is stabilized at the normal position, so that the initial loss stroke during operation can be stabilized and the piston The retreat limit can regulate the retreat of the piston.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a master cylinder of the present invention.

FIG. 2 is a perspective view of a primary piston in the first embodiment.

FIG. 3 is a perspective view of a retainer according to the first embodiment.

FIG. 4 is a partial cross-sectional view taken along the line IV-IV in FIG.

FIG. 5 is a sectional view showing a second embodiment of the master cylinder of the present invention.

FIG. 6 is a perspective view of a retainer according to a second embodiment.

7 is a partial cross-sectional view taken along the line VII-VII of FIG.

FIG. 8 is a sectional view of a conventional master cylinder.

[Explanation of symbols]

 1, 40, 50 Master cylinder 2 Cylinder housing 3 Body body 3a Opening 4 Cap 5 Primary piston 6 Secondary piston 7,8 Piston guide 9 Sleeve 9a Groove 10 First pressure chamber 12,51 Spring mechanism 14 Return spring 15 Guide screw 16 , 42, 52 Retainer 26, 27 Passage 28 Seal member 41 Engaging part 42c, 52d End part 52a Peripheral part 52c Leg part

Claims (2)

[Scope of utility model registration request] 1. A cylinder housing is constituted by a body main body having an opening at one end and a cap which is coupled to the body main body and closes the opening, and a piston is fitted in the cap to insert the cap into the cylinder housing. A master cylinder guided by a piston guide and a sleeve, which are slidably disposed on the piston and provided with a passage communicating with an external fluid passage, wherein the piston is provided with an engaging portion, and the piston, the piston guide, and the sleeve are provided. A seal member that seals in one direction is disposed on the surface along the line, and a retainer member having a Gotoku shape is disposed between the engagement portion of the piston and the seal member so that they can be engaged with each other. The piston is retracted and the piston is retracted, and the seal member is pushed onto the piston guide. A master cylinder characterized by pressure. 2. A cylinder housing is constituted by a body main body having an opening at one end and a cap which is coupled to the body main body and closes the opening, and the piston comprises:
A master which is slidably disposed in the cylinder housing by inserting the cap, is biased in the backward direction by a spring mechanism, and is guided by a piston guide and a sleeve having a passage communicating with an external fluid passage. In the cylinder, a seal member that seals in one direction is arranged on a surface along the piston, the piston guide, and the sleeve, and the spring mechanism includes a return spring whose one end abuts on an end surface of the piston, The guide member is fixed to the end surface of the piston, and a retainer member in the shape of a mountain hat is slid and engaged with the guide member, and the other end of the return spring is abutted to mount the retainer member. A plurality of leg portions extend in the piston side direction from a peripheral edge portion of the retainer member to which the return spring is attached, and the ends of the leg portions serve as the seal member. A master cylinder, wherein the master cylinder is configured to be engageable with the piston, and to restrict the retreat of the piston at the retreat limit of the piston and to press the seal member against the piston guide.