JP2558706Y2 - Master cylinder - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a master cylinder used for various brake devices of a motor vehicle.

[0002]

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

The body main body 3 has an opening 3a at one end, and a female screw 3b is formed on an inner peripheral surface of the opening 3a.
Are formed. On the other hand, a male screw 4a is formed on the outer peripheral surface of one end of the cap 4, and this cap 4
The male screw 4a is screwed into the female screw 3b of the body main body 3 to be mounted on the body main body 3.

[0004] Inside the body 3, the tip of a primary piston 5 and a secondary piston 6 are fitted with the cap 4 and slidably disposed through piston guides 7, 8. A first pressure chamber 10 is formed inside the body 3 by the primary piston 5 and a resin sleeve 9 for guiding the piston 5, and a second pressure chamber 10 is formed by the secondary piston 6 and the inner wall surface of the body 3. A pressure chamber 11 is formed.

[0005] The first pressure chamber 10 and the second pressure chamber 11 are provided with a spring mechanism 12 and a spring mechanism 12, respectively, for urging the primary piston 5 and the secondary piston 6 in the backward direction.
13 are provided. The spring mechanism 12 includes a return spring 14, a guide screw 15, and a mountain-top hat-shaped retainer 1.
6 One end of the return spring 14 is held on the bottom surface of a 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 of the retainer 16. The guide screw 15 is screwed into the bottom surface of the spring holding hole 5a so as to protrude from the bottom surface by a predetermined length in the piston axial direction. In the retainer 16, a hole provided at the top of the mountain hat shape slides freely on the guide screw 15 within a predetermined stroke range, and engages with the end.

The spring mechanism 13 includes a return spring 17, a spring holding guide 18, and a mountain hat-shaped retainer 19, and its functions are the same as those of the spring mechanism 12.

As described above, 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 master cylinder 1 Is increased, and the hydraulic fluid is sent from the outlets 20 and 21 to a brake system (not shown).

In the master cylinder 1, the primary piston 5 and the secondary piston 6 are connected to the sleeve 9 guided in the cylinder housing 2 and the supply fluid passages 23, 24, 25 from the oil reservoir 22, respectively. , 27 are fitted and guided by piston guides 7, 8 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. An annular one-way seal member 28 is provided across this portion to form a liquid supply path when the liquid supply path is formed. That is, when the brake operation is released, the inside of the first pressure chamber 10 becomes a negative pressure, so that the one-way seal member 28 is deformed and loses its sealing function, thereby promoting the replacement fluid from the fluid supply path. 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 pushed into the first and second pressure chambers 10 and 11, respectively, the pressure chambers 10, 1
1 rises, and these one-way sealing members 28,
Numeral 29 is pressed against the respective sealing surfaces by the liquid pressure to seal.

Note that 5b and 6b are primary pistons 5
And a small hole formed in the outer peripheral surface of the secondary piston 6 and the oil reservoir 2 at the brake release position.
A replenishing liquid passage from the second to the first and second pressure chambers 10 and 11 is formed. Further, the annular seal members 30, 31a, 31
b, 32 and 33 are arranged in the cylinder housing 2.

[0012]

However, when the primary piston 5 and the secondary piston 6 are retracted and the operating master cylinder 1 returns to the non-operating state (brake release state), the first pressure chamber is particularly required. There is a possibility that the inside of the pressure chamber 10 temporarily becomes a negative pressure, the one-way seal member 28 is deformed so as to be drawn into the pressure chamber 10, and the mounting position varies.

As described above, the small hole 5b of the primary piston 5 every time the master cylinder 1 is not operated.
Then, the position of the one-way seal member 28 is not stable.
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 the first pressure chamber 10
There is a problem that the stroke until the one-way seal member 28 is returned to the proper mounting position by increasing the liquid pressure in the inside, that is, the initial loss stroke is not stable.
Further, the structure for always holding the one-way seal member 28 at the proper mounting position prevents appropriate deformation of the seal member 28 when the primary piston 5 is retracted,
Insufficient replenisher flow rate cannot be obtained.

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

The present invention has been made in view of such a point.
The purpose is to solve the above-mentioned problem, and to stabilize the initial loss stroke by stabilizing the position of the seal member, which is disposed on the pressure chamber side and seals in one direction, in a non-operating state at a regular position. Another object of the present invention is to provide a master cylinder having a restricted piston retraction limit.

[0016]

The configuration 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 connected to the body main body to close the opening, and a piston is inserted into the cylinder housing to form the cylinder housing. A master cylinder guided by a piston guide and a sleeve slidably disposed within and having a passage leading to an external fluid passage,

The piston is provided with an engaging portion,
A seal member for sealing in one direction is provided on a surface along the piston, the piston guide and the sleeve, and a pentagonal retainer member is provided between the engagement portion of the piston and the seal member. Then, the pistons are made to be engageable with each other, and the retraction of the piston is restricted at the retreat limit of the piston, and the seal member is pressed against the piston guide.

(2) A cylinder housing is constituted by a body main body having an opening at one end and a cap connected to the body main body to close the opening, and a piston is inserted into the cylinder housing to insert the cap. In the master cylinder, which is slidably disposed within and is urged in a retreating direction by a spring mechanism, and is guided by a piston guide and a sleeve having a passage communicating with an external fluid passage,

A seal member for sealing in one direction is provided on a surface along the piston, the piston guide and the sleeve, and the spring mechanism includes a return spring having one end abutting on an end surface of the piston; A guide member fixed to the end face of the piston, a mountain hat-shaped retainer member slidably engaged with the guide member, and abutting the other end of the return spring to mount the return spring; A plurality of legs extend from the peripheral edge of the retainer member where the return spring is mounted in the piston side direction, and the ends thereof can be engaged with the seal member. It is characterized in that retraction is restricted and the seal member is pressed against the piston guide.

[0021]

Since the present invention is constructed as described above, a pentagonal retainer member is disposed between the engagement 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 periphery of the retainer member that engages the piston via a guide member, and by allowing its ends to engage with the seal member, when not in operation, The retraction of the piston is restricted by the retreat limit of the piston, and the sealing member is pressed against the sealing surface to seal.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. 1 to 4 show a first embodiment of the master cylinder of the present invention. The same members as those in FIG.

In FIGS. 1 to 4, a resin sleeve 9 provided for guiding the primary piston 5 inside a master cylinder 40 is provided with a first pressure chamber 10.
A plurality (eight in the figure) of grooves 9a are provided on the inner peripheral surface of the inner peripheral surface at equal intervals along the inner periphery to communicate between the hydraulic fluid outlets 20.

A plurality of engaging portions 41 are formed so as to radially protrude from the outer peripheral surface of the end of the primary piston 5 and can be inserted into the grooves 9a of the sleeve 9, respectively. , The engaging portion 4
1 and a seal member 28 for sealing the pressure chamber 10 in one direction.

As shown in FIG. 3, the retainer 42 has a shape of a three- or four-legged ring (a three- or four-legged device that is placed on a charcoal or the like in a brazier and is put on an iron bottle) as shown in FIG. And a plurality (eight in this embodiment) of leg portions 42b are equally spaced along the ring from the annular portion 42a. It is erected on the side, and an end 42c is formed at its tip. And these ends 42c
Is engaged with each of the engaging portions 41 at the retreat limit of the primary piston 5. These legs 42b
The width of the end portion 42c is such that it can be inserted into the groove 9a of the sleeve 9.

Since the retainer 42 is normally disposed in engagement with the seal member 28, the retainer 42 is engaged when the master cylinder 40 is operated, that is, when the primary piston 5 is pushed into the cylinder housing 2. The engaging portions 41 disengage from the ends 42c of the retainer 42 and are separated from each other.

Next, when the master cylinder 40 is not operated,
That is, the primary piston 5 retreats, and at the retreat limit, the engagement portion 41 engages with the end 42c of the retainer 42 to regulate the primary piston 5 from retreating further. At the same time, the seal member 28 is pressed against the piston guide 7 at a proper position from the spring mechanism 12 via the annular portion 42a of the retainer 42.

FIGS. 5 to 7 show a second embodiment of the present invention. The same members as those in FIG. 8 are denoted by the same reference numerals and the description thereof will be omitted. 5 to 7, the primary piston 5 inserted into the master cylinder 50 is
The spring mechanism 51 for urging in the backward direction is similar to the spring mechanism 12 and includes a return spring 14 and a guide screw 15.
And a retainer 52 in the shape of a deformed mountain hat.

One end of the return spring 14 has a spring holding hole 5a formed in the end face of the primary piston 5.
And the other end is a peripheral edge 52a of the retainer 52.
Is held. The guide screw 15 is screwed into the bottom surface of the spring holding hole 5a so as to protrude from the bottom surface by a predetermined length in the piston axial direction. In the retainer 52, a hole 52b provided at the top of the mountain hat shape slides freely on the guide screw 15 within a predetermined stroke range, and engages with the end.

As shown in FIG. 6, the retainer 52 has a plurality of (eight in this embodiment) leg portions 52c arranged at equal intervals along the peripheral edge portion 52a from the peripheral edge portion 52a. On the 5th side, it extends in the oblique radial direction, and an end 52d is formed at the tip. These ends 52d are engaged with the seal member 28 at the retreat limit of the primary piston 5. These legs 5
The width of 2c and the end 52d is such that it can be inserted into the groove 9a of the sleeve 9.

The retainer 52 constitutes a spring mechanism 51 of the primary piston 5, and is pushed together with the piston 5 when the master cylinder 50 is operated.
The end 52d of the retainer 52 disengages from the seal member 28 and separates from each other.

Next, when the master cylinder 50 is not operated, the retainer 52 engages with the guide screw 15 fixed to the piston 5 at the retreat limit of the primary piston 5, and the end 52d is connected to the seal 52. Engagement with member 28 restricts further retraction of primary piston 5. At the same time, the seal member 28 is pressed against the piston guide 7 at a proper position from the spring mechanism 51 via the end 52d of the retainer 52.

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, 5
An initial loss stroke of 0 is always stable.

The technique of the present invention is not limited to the technique in the above-described embodiment, but may be implemented by means of other modes having the same functions. Can be changed or added.

[0035]

As is apparent from the above description, according to the master cylinder of the present invention, a pentagonal retainer member is disposed between the engagement portion of the piston and the seal member, and each of the retainer members is provided. By allowing a plurality of legs to extend from a peripheral portion of a retainer member that engages with the piston via a guide member, and allowing the ends to engage with the seal member, When not operating, the sealing member is pressed against a predetermined sealing surface to seal.

Therefore, when the master cylinder 1 is not operated,
Since the position of the seal member is stabilized at a regular position,
The initial loss stroke during operation can be stabilized, and the retraction limit of the piston can be restricted by the retraction limit of the piston.

[Brief description of the 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 according to the first embodiment.

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

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

FIG. 7 is a partial cross-sectional view taken along line VII-VII of FIG. 5;

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

[Explanation of symbols]

 1, 40, 50 Master cylinder 2 Cylinder housing 3 Body main 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 Sealing member 41 Engagement part 42c, 52d End 52a Peripheral edge 52c Leg

Claims (2)

(57) [Scope of request for utility model registration] 1. A cylinder housing comprising a body main body having an opening at one end and a cap coupled to the body main body to close the opening, and a piston is fitted into the cylinder housing to form a cylinder housing. A master cylinder guided by a piston guide and a sleeve that is slidably disposed on the piston guide and has a passage that communicates with an external fluid path, wherein an engagement portion is provided on the piston, the piston, the piston guide, and the sleeve. A seal member that seals in one direction is disposed on a surface along, and a pentagonal retainer member is disposed between the engagement portion of the piston and the seal member so that they can be engaged with each other. The retraction limit of the piston restricts the retraction of the piston and pushes the seal member against the piston guide. A master cylinder characterized by pressure. 2. A cylinder housing comprising a body main body having an opening at one end and a cap coupled to the body main body to close the opening, wherein the piston has:
A master which is slidably disposed in the cylinder housing with the cap inserted therein, urged in a retreating direction by a spring mechanism, and guided by a piston guide and a sleeve provided with a passage leading to an external fluid passage. In the cylinder, a seal member that seals in one direction is disposed on a surface along the piston, the piston guide, and the sleeve, and the spring mechanism includes a return spring, one end of which contacts an end surface of the piston; A guide member fixed to the end face of the piston, a mountain hat-shaped retainer member slidably engaged with the guide member, and abutting the other end of the return spring to mount the return spring; A plurality of legs extend from the peripheral edge of the retainer member where the return spring is mounted in the piston side direction, and the ends of the legs extend to the seal member. A master cylinder, wherein the master cylinder is made to be able to engage, restricting retraction of the piston at a retreat limit of the piston, and pressing the seal member against the piston guide.