JPH0751416Y2 - Plunger type master cylinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a plunger type master cylinder used in a vehicle or the like.

[Conventional technology]

As a master cylinder of this type, it has been used in the past in the actual development of Sho 62-1967.
Some are described in Japanese Patent Publication No. 70.

FIG. 4 shows the structure of the liquid passage that connects the pressure chamber 63 defined by the plunger 62 and the hydraulic fluid reservoir in the cylinder hole 61 of the cylinder body 60 in this conventional master cylinder. In the figure, this plunger 62
Is a sleeve having a cylindrical portion 64 at its tip and fitted in a large diameter portion 65 of a cylinder hole 61 formed in the cylinder body 60.
66 is slidably penetrated. An annular groove 67 is defined between the rear end of the sleeve 66 and the hole step portion 61A, and a sealing material 68 is formed in the groove 67.
Is installed. An inner peripheral groove 66A including the rear end, an outer peripheral groove 66B, and a radial passage 66C opening to both grooves are formed at the rear end of the sleeve 66, and the outer peripheral groove 66B is connected to the reservoir formed in the cylinder body 60. It communicates with a hydraulic fluid reservoir (not shown) through the portion 69. The pressure chamber 63 includes a plurality of small holes (relaxation holes) 64A formed in the tubular portion 64, a low pressure side of the sealing material 68,
The working fluid reservoir is connected to the working fluid reservoir through a fluid passage formed by the inner circumferential groove 66A, the passage 66C, and the outer circumferential groove 66B, and the liquid is supplied to the pressure chamber 63 through a space between the seal material 68 and the outer circumferential surface of the plunger 62.

[Problems to be solved by the device]

In this conventional device, the pressure chamber 63 is connected to the hydraulic fluid reservoir via a plurality of small holes 64A formed in the plunger 62, but the fluid supply is performed by the deformation of the inner peripheral lip of the seal material 68. I have to.

For this reason, when the inner peripheral lip is deformed, the return position at the time of restoring deformation varies, so that the position of the small hole 64A cannot be brought very close to the sealing material 68 side, and there is a problem that the play becomes large. .

The present invention has been made to solve the above problems, and an object of the present invention is to provide a plunger type master cylinder that can reduce the play required for the generation and disappearance of hydraulic pressure as compared with the conventional case.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention provides a seal portion at the tip of the inner peripheral lip of the seal material, which is in close contact with the outer periphery of the plunger, and a plurality of protrusions are provided on the low pressure side of the seal portion to form a liquid path between the protrusions. The small hole is formed in this liquid passage, and the end of the inner peripheral lip of the sealing material is brought into contact with the groove surface to prevent free deformation of the inner peripheral lip. The seal portion with the inner surface of the cylinder hole is formed with a liquid replenishing hole on the low pressure side of the seal portion, and an outer peripheral lip deformation cavity is formed in the groove.

[Action]

In the present invention, the inner peripheral lip of the seal material is prevented from freely deforming, and the liquid replenishment to the pressure chamber is performed by the deformation of the outer peripheral lip toward the deformed cavity side. There is no variation in the positions of the seal portion of the peripheral lip and the plunger small hole.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a cylinder body 1 of a master cylinder has a first half 2 having a bottomed cylinder and a second half having a bottomed cylinder.
Of the first half 2 and the opening of the second half 3 is screwed into and integrated with the opening of the first half 2. The cylindrical hole 4 of the first half body 2 is a stepped hole, and has a hole 6 on the bottom 5 side and a hole 8A having a larger diameter than this and having a tapered hole portion 8A that expands toward the opening portion 7. The outer periphery includes a boss portion 10 having an inner hole 9 and a boss portion 12 having an inner hole 11 at an upper position in the drawing.
And a pair of pressure discharge bosses (not shown) are also formed on the back of the boss. A hydraulic fluid reservoir (not shown) is connected to the bosses 10 and 12. The tapered hole portion 8A of the hole 8 of the first half body 2 defines a space 13 between the tapered hole portion 8A and the end face portion of the second half body 3, and the tapered hole portion 8A has a through hole 14 that opens into this space 13. Has been formed. This through hole 14 is an inner hole of the boss portion 12.
Connect to 11. The inner hole 9 of the boss portion 10 communicates with the hole 8 through a through hole 15 that opens at a corner of the bottom 8C of the hole 8. 8B shows a portion of the hole 8 between the tapered hole portion 8A and the bottom 8C. Further, a recess 6A (described later) into which a sealing material 16 (described later) is fitted is formed on the bottom 8C side of the hole 6 of the first half body 2, and the recess 6A is formed in the upper portion of the inner peripheral surface of the hole 6. Is formed with an axial groove (which serves as a liquid passage) 17. The cylindrical hole 18 of the second half 3
A sleeve 19 is inserted between the first half body 2 and the cylindrical hole 4 of the first half body 2. The sleeve 19 defines a liquid passage 20 between the sleeve 19 and the inner peripheral surface of the second half body 3. The liquid passage 20 communicates with the space 13. The sleeve 19 is a cylinder having a large number of axially extending reinforcing rims 19A on the inner peripheral side, and a rear end having a recess 22 (described later) into which a sealing material 21 (described later) is fitted, on the rear end surface. Part is fitted to the bottom of the cylindrical hole 18 with a sealing member 23 interposed between the part and the bottom of the cylindrical hole 18 of the second half body 3.
The front end portion, which abuts against 24 and is fitted to the second half body 3, extends to the first half body 2 side, is fitted into the hole portion 8B at the fitting portion 25, and is bottomed.
It extends toward the 8C side and is in contact with the guide member 26 fitted inside the bottom 8C of the hole 8. The annular projection 19B projecting from the front end surface of the sleeve 19 and the projection 26A projecting from the end surface of the guide member 26 abut each other to form outer and inner annular recesses for fitting the sealing member by both projections and both end surfaces. Then, the sealing member 27 having an inner / outer double structure is fitted in both the recesses. The guide member 24 has a radial liquid passage 28 and communicates with the liquid passage 20. The guide member 26 is also a plate-shaped body having a radial liquid passage 29, and is fitted over the bottom of the hole 8 and the recess 6A of the hole 6,
An annular passage 30 is defined between the corner of the bottom 8C and the corner. A through hole 15 is opened in this passage 30.

As shown in the enlarged view of FIGS. 2 and 3, the sealing material 21 has a seal portion a at the tip of the inner peripheral lip A, and a plurality of protrusions b extending from the seal portion a to the base portion B. Are formed to define a liquid path D1 between the protrusions b. Further, the tip of the outer peripheral lip C also has a seal portion c, and a plurality of liquid supply grooves D2 extending from the seal portion c to the base portion B are formed. The seal member 21 elastically contacts the seal portion a of the inner peripheral lip A with the outer periphery of the main plunger 42, the seal portion c of the outer peripheral lip C with the outer peripheral surface of the recess (annular groove) 22, and the inner peripheral lip A. Is abutted against the end surface of the groove inner wall 22A of the recess 22 and is fitted into the recess 22 with its movement restricted in the axial direction by the guide member 24. The recess 22 is an empty space where the outer peripheral lip C of the seal material 21 can be deformed. The place S is left. The inner wall 22A of the groove of the recess 22 ends slightly on the front end side from the rear end surface of the sleeve 19. The recess 6A and the sealing material 16 are similar to the recess 22 and the sealing material 21.

The hole 6 of the first half body 2 and the sleeve 19 form a cylinder hole 40, and a slave plunger 41 is slidably inserted into the cylinder hole 40 with the opening side thereof facing the bottom of the hole 6. The main plunger 42 is slidably inserted with the opening side toward the bottom of the sub plunger 41, and the main plunger 42 penetrates the seal member 21 and the guide member 24 closely and extends to the outside.

The sub-plunger 41 is biased toward the main plunger 42 by the return spring 43 to define the sub-pressure chamber X between the sub-plunger 41 and the bottom 5 of the hole 6. The return spring 43 extends from the inner bottom of the slave plunger 41 coaxially to a shaft portion 44 having a base-like base portion and a retainer 45 which is loosely inserted through the shaft portion 44 and abuts on the bottom 5 of the hole 6. It is stretched. The main plunger 42 is also urged rearward by the return spring 46 to define the main pressure chamber Y with the sub plunger 41. The return spring 46 extends from an inner bottom of the main plunger 42 coaxially, to a shaft portion 47 having a base-like base portion, and a retainer 48 to which the shaft portion 47 loosely penetrates and abuts on the outer bottom of the sub plunger 41. The tension is higher than the tension of the spring 46 and is preloaded by both retainers. The secondary plunger 41 is formed with a plurality of radial small holes 41A at positions corresponding to the liquid passages 29 of the guide member 26, and the main plunger 42 is also provided with a plurality of radial small holes 42A. It is formed at a position corresponding to the liquid passage 28 of the member 24. Incidentally, the sealing material 21 and the sealing material 16, the small hole 42A of the main plunger 42 in each liquid passage D1,
The sub plunger 41 is mounted so that the small hole 41A is opened. Pipes are connected to the sub pressure chamber X and the main pressure chamber Y through the boss portion (not shown).

Further, this master cylinder is shown assembled to the front shell 50 of the negative pressure booster.

This type of master cylinder movement is well known and will be briefly described below.

In this configuration, when the brake is loosened or pumped, in the pressure chamber X, the inner hole 9 of the boss portion 10, the through hole 15, the liquid replenishment groove D2 of the seal material 16, the outer peripheral lip C of the seal material 16 and the concave portion.
The hydraulic fluid is replenished from a hydraulic fluid reservoir (not shown) through the fluid passage formed by the space S between the groove of 6A, and the main pressure chamber Y is provided with the inner hole 11 of the boss portion 12, the fluid passage 20, and the sealing material 21. Between the liquid replenishment groove D2, the outer peripheral lip C of the seal material 21 and the groove of the recess 22,
The working fluid is supplied from the working fluid reservoir through the fluid passage formed by the void S, and the inner peripheral lip A is prevented from being deformed at the time of replenishment.

When the main plunger 42 is driven to the left in the figure, when the small hole 42A is closed by the seal member 21, the main pressure chamber Y
Fluid pressure begins to build up inside. When the main plunger 42 moves to the left, the sub plunger 41 also moves to the left, and when the small hole 41A is closed by the sealing material 16, hydraulic pressure starts to be generated in the sub pressure chamber X. The liquid pressure in the main pressure chamber Y and the sub pressure chamber X increases due to the further leftward movement of the main plunger 42 and the sub plunger 41, and the hydraulic pressure generated in the sub pressure chamber X and the main pressure chamber Y is not shown in the drawing. Is supplied to the brake circuit (not shown) through a pipe.

When the brake is released, the liquid in the pressure chamber Y flows from the small hole 42A to the liquid passage D.
1. Return to the hydraulic fluid reservoir via the liquid passage 28 and the liquid passage 20 of the guide member 24, and the liquid in the pressure chamber X flows from the small hole 41A to the liquid passage D1.
It returns to the hydraulic fluid reservoir via the fluid passage 29 of the guide member 26 and the through hole 15.

As described above, in this embodiment, the seal portion a dedicated to the seal is provided on the inner peripheral lips A of the sealing materials 16 and 21, and the inner peripheral lips A,
Liquid passages D1 and D2 are formed in the outer peripheral lip C, and the outer peripheral lip C has a seal portion c, but is deformable, and this deformation secures a liquid supply passage to the pressure chamber. Since it is in elastic contact with the plunger at all times, the positional relationship between the seal portion a and the small holes 41A, 42A serving as loosening holes for each plunger does not vary. Therefore, the gap between the seal portion a and the loosening hole of each plunger can be sufficiently close, and the play of the plunger can be made smaller than in the conventional case.

[Effect of device]

As described above, in the present invention, the inner peripheral lip of the seal material is prevented from freely deforming, and the liquid supply to the pressure chamber is performed by the deformation of the outer peripheral lip of the seal material. The position of the small hole of the plunger can be brought closer to the seal portion, and the play of the plunger can be made smaller than in the conventional case.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIGS. 2 and 3 are sectional views and a front view of a half portion of the sealing material in the above embodiment, and FIG. 4 is a seal in a conventional plunger type master cylinder. It is sectional drawing which shows the structure of a part. 1 …… Cylinder body, 19 …… Sleeve, 6A, 22 …… Concave, 16,21 …… Seal material, 41,42 …… Plunger, 41
A, 42A ... small hole, A ... inner lip, B ... base part,
C ... Outer lip, a, b ... Seal part, c ... Protrusion,
D1 ... Liquid path, D2 ... Liquid supply groove, S ... Deformation void,

Claims (1)

[Scope of utility model registration request] 1. A cylinder body 1 having a cylinder hole 40 formed therein.
And sealing materials 16 and 21 fitted in grooves 22 formed on the inner periphery of the cylinder hole 40 to form inner and outer peripheral lip portions A and C, and the sealing material 1.
Plungers 41 and 42 arranged to penetrate through the pressure chambers X and Y and penetrating the pressure chambers X and Y, and pressure chambers X and Y at the time of non-operation formed in the plungers 41 and 42 and the low pressure side of the sealing members 16 and 21. Small hole to contact 41A, 42
When the small holes 41A and 42A of the plungers 41 and 42 during operation are disconnected from the low pressure side of the sealing materials 16 and 21 by the sealing materials 16 and 21, pressure is generated in the pressure chambers X and Y. In the plunger type master cylinder configured as described above, a seal portion a is provided at the tip of the inner peripheral lip A of the seal members 16 and 21 so as to make a tight elastic contact with the outer periphery of the plungers 41 and 42, and a plurality of low pressure sides of the seal portion a are provided. Providing protrusions b to form a liquid path D1 between the protrusions b,
The small holes 41A, 42A are opened in the liquid passage D1, and the sealing material 16,
The end portion of the inner peripheral lip A of 21 is brought into contact with the groove surface 22A to prevent free deformation of the inner peripheral lip A, and the outer peripheral lip C
A plunger type master cylinder in which a seal portion c with the inner surface of the cylinder hole 40 is formed at the tip portion, a liquid replenishing hole D2 is formed on the low pressure side of the seal portion c, and an outer peripheral lip deformation space S is formed in the groove 22.