JPH01269657A - Master cylinder - Google Patents

Abstract

PURPOSE:To avoid the delay in the response in pressure rise in a hydraulic chamber by forming a plurality of elastic projections in the specific constitution, on the front surface side of a unidirectional sealing member, in a master cylinder for vehicle brake which is equipped with the unidirectional sealing member in which an inner peripheral lip is closely attached onto the other peripheral surface of the plunger which dividedly forms a hydraulic chamber. CONSTITUTION:As for a tandem master cylinder M, two plungers 161 and 162 are fitted into a sleeve 13 fitted into a cylinder body 1. The sealing chambers g1 and g2 and hydraulic pressure chambers 171 and 172 are dividedly formed by the plungers 161 and 162, and the unidirectional sealing members 351 and 352 which permit the flow of the working oil only in one direction from radial grooves 341 and 342 are installed into the sealing chambers g1 and g2. In this case, on each sealing member 351 (similar in case of 352), a plurality of elastic projections (l) are formed at equal intervals in the inner peripheral direction on an annular base (k) so that the parts between the basic parts of the inner and outer peripheral lips (h) and (j) are connected, and when the plunger advances, the sealing member 351 is held at a retreat position, and when the plunger retreats, the advance of the sealing member 351 accompanied with the decompresson of the hydraulic cahmber 171 is permitted.

Description

Detailed Description of the Invention A3 Object of the Invention (]) Industrial Application Field The present invention relates to a master cylinder used in a vehicle brake cylinder, etc., and in particular, to a cylinder body equipped with an oil reservoir and a cylinder hole in the cylinder body. a seal chamber which is slidably supported by the bulkhead collar in the longitudinal direction and is located immediately in front of the bulkhead collar and communicates with the oil reservoir; and a front portion r of the seal chamber; plungers each defining hydraulic chambers that communicate with each other; and a return spring that biases the plunger in a backward direction.
It consists of a one-way seal member that is installed in the seal chamber and has an inner lip in close contact with the circumferential surface of the plunger (the plunger), and when the plunger is at a predetermined retraction limit, hydraulic pressure is applied immediately after the inner lip of the one-way seal member. This article relates to an improvement in which a relief port that communicates with the chamber is drilled.

(2) Conventional technology Conventionally, in this type of master cylinder, the length of the seal chamber in the sliding direction of the plunger is set larger than the length of the one-way seal member in the same direction (see Japanese Patent Publication No. 62-33977). .

The reason for setting the dimensions in this way is that when the plunger retreats, the pressure in the hydraulic chamber is reduced and the one-way seal member is advanced, forming a relatively wide supply oil passage between the member and the bulkhead collar. This is to improve the efficiency of supplying hydraulic oil to the hydraulic chamber.

(3) Problems to be Solved by the Invention However, with the above configuration, when the plunger is advanced to generate hydraulic pressure in the hydraulic chamber, the one-way seal member is initially dragged by the plunger and moves forward, and then the hydraulic chamber is moved forward. Since the one-way seal member retreats due to the increase in pressure, there is a problem in that a delay in the pressure increase response of the hydraulic chamber occurs as the one-way seal member moves back and forth.

An object of the present invention is to provide the master cylinder that can solve the above problems.

B9 Structure of the Invention (1) Means for Solving the Problems The present invention provides a cylinder body provided with an oil reservoir, a partition collar fitted into a cylinder hole of the cylinder body, and a partition wall collar that slides in the front-rear direction. a plunger which is freely supported and defines a seal chamber immediately in front of the bulkhead collar and communicating with the oil sump, and a hydraulic chamber pedestal communicating with the front of the seal chamber, and biasing the plunger in a backward direction; and a one-way sealing member that is installed in the seal chamber and has an inner circumferential lip brought into close contact with the outer circumferential surface of the plunger,
In a master cylinder in which a relief boat is bored in the langeer and communicates with the hydraulic chamber immediately after the inner peripheral lip of the one-way seal member when the langeer is at a predetermined retraction limit, a seal is provided on the front side of the one-way seal member. in contact with the room wall,
The one-way seal member is held in a retracted position when the plunger moves forward, but an elastic protrusion is provided that allows the one-way seal member to move forward as the pressure in the hydraulic chamber is reduced when the plunger moves back. .

(2) Function With the above structure, when the plunger moves forward, the elastic protrusion prevents the one-way seal member from moving forward by being dragged by the plunger, and the one-way seal member does not move backward. This makes it possible to avoid a delay in response to increasing the pressure in the hydraulic chamber.

On the other hand, when the plunger retreats, the one-way seal member moves forward due to compressive deformation of the elastic protrusion, so a relatively wide replenishment oil passage can be formed between that portion +4 and the bulkhead collar to improve the efficiency of hydraulic oil replenishment. can.

(3) Embodiment In FIG. 1, M is a tandem type master cylinder for a two-system hydraulic brake of an automobile, and its cylinder body 1 is attached to the front surface of a booster shell 2 of a negative pressure booster B supported by a vehicle body (not shown). The rear end is fixed.

An auxiliary oil reservoir 3 is integrally provided on the upper side of the cylinder body 1, and a main oil reservoir 4 is connected thereto. The main oil reservoir 4 has a cap 5 at its upper end, and is provided with a known oil level sensor 6 supported by the cap 5 inside.

The inside of the auxiliary oil reservoir 3 is divided by a partition wall 7 into first and second oil reservoirs, 8 g, and these oil reservoirs 8° and 8□ are each supplied with hydraulic oil from the main oil reservoir 4.

First and second oil sump8. ．． 8g each has 9 through holes,,!
0 communicated with the stepped hole 10 of the cylinder body 1 via L
The stepped hole 10 includes a first hole 10a with a closed front end, a second hole 10b having a larger diameter than the first hole 10a and continuous to the rear end, and a second hole 10b having a larger diameter than the second hole 10b and continuous to the rear end. It consists of an open third hole 10c, into which a sleeve 13 forming a part of the cylinder body 1 is fitted,
Therefore, the first hole 10a, the second hole 10b, and the through hole 13c of the sleeve 13 form a cylinder hole H.

The large-diameter front part a of the front bulkhead collar 121 is fitted into the second hole 10b, and the sleeve 13 is in contact with the rear surface of the flange part C between the large-diameter front part a and the small-diameter rear space of this collar 12+, and the small-diameter rear part a is fitted into the second hole 10b. The sleeve 13 is fitted into the front end of the through hole 13c of the sleeve 13. In the through hole 13c of the sleeve 13, the large diameter front part a of the rear bulkhead collar 12□ is fitted into the stepped hole f existing at the rear end, and the space between the large diameter front part a and the small diameter rear space of this collar 12g is fitted. The bearing 14 disposed in the third hole 10C is in contact with the rear surface of the flange portion C, and the small diameter rear surface is in contact with the bearing 14.
is fitted into the recess 15 of. The mounting structure of the bearing 14 to the cylinder body 1 will be described later.

Front bulkhead collar 12. The outer peripheral surface of the flange portion C and the third
A front annular oil chamber 11 is connected to the front through hole 91 between the inner peripheral surfaces of the holes 10c. is defined. Also rear bulkhead color 12! A rear annular oil chamber 112 defined between the outer peripheral surface of the flange portion C and the inner peripheral surface of the third hole 10c is connected to the rear through hole 9□ via an axial groove 13a and an annular groove 13b running on the outer peripheral surface of the sleeve 13. It goes through.

Front bulkhead collar 12. and through hole 13 of sleeve 13
c Front and rear bulkhead collars 12t and sleeves 1
A pair of front and rear plungers 161.3 are located at the rear of the through hole 13c.
16□ are fitted to each other so as to be slidable in the front and rear directions.

Front plunger 16. and the second hole 10b, the front bulkhead collar 12. A front seal chamber g is defined immediately in front and communicates with the front annular oil chamber 11, and a front plunger 16. and a front hydraulic chamber 17. which communicates with the front part of the front seal chamber GL between the front end wall of the first hole 10a. is defined.

The rear plunger 16□ and the stepped hole part f of the through hole 13c are located just in front of the rear bulkhead collar 12□, and the rear annular oil chamber 1
1□ is defined, and both plungers 16. ．． 16□ Rear hydraulic chamber 17. is defined.

Front and rear hydraulic chambers 17. ．． 17□ communicates with each of the two brake hydraulic circuits via the front and rear output boats 1B, , 18□ of the cylinder body 1.

The rear end of the rear plunger 16□ extends to the rear of the cylinder body 1 by passing through a bearing 14 that slidably supports the outer peripheral surface of the rear plunger 16□, and further passes through the front wall of the booster shell 2 to receive the output of the negative pressure booster B. Connect to rod 19.

Booster shell 2 through which this rear plunger 162 penetrates
In order to prevent the internal negative pressure from leaking through the through hole 20 of the rear plunger 16, a sealing member 21 is sandwiched between the cylinder body 1 and the booster shell 2 to bring the inner peripheral lip into close contact with the outer peripheral surface of the rear plunger 16□. .

1st. As clearly shown in FIG. 7, in order to communicate between the rear hydraulic chamber 17 and the rear output boat 18□, the sleeve 13 has a plurality of axial grooves 23 of two types, long and short, running on its inner peripheral surface. ．． 23! , a horizontal hole 24, and an annular groove 25 running on the outer circumferential surface. Long axial groove 23. The rear end opens to the front of the rear seal chamber gt, thereby opening the rear seal chamber g.
z communicates with the rear hydraulic chamber 11t.

Rear plunger 16. A bottomed spring holding hole 312 is provided in the front end surface of the spring holding hole 312, and a rear return spring 30.
is accommodated. In addition, 1. The spring holding hole 31. A bolt 32 protruding axially by a certain length from the end wall of the rear return spring 30 is screwed onto this bolt 32.
A hat-shaped spring holding cylinder 33 supporting the front end of the square is slidably connected within a certain stroke range.

Does the flange portion 33a of the spring holding cylinder 33 protrude in the radial direction? ■Equipped with several protrusions P, each protrusion P is a short axial groove 23 of the sleeve 13. is engaged with.

Its axial groove 23. The rear end is closed (divided) by a stopper wall 29 that is integrated with the sleeve 13, and this stopper wall 2
When the projection p comes into contact with 9, the rear plunger 1
6. A predetermined retraction limit is determined.

On the other hand, in the front plunger 16, a bottomed spring holding hole 31. is provided, and the hole 31. A front return spring 301 that biases the front plunger 161 in the backward direction is housed in the front return spring 301 . The predetermined retraction limit of the front plunger 16+ is determined by the fact that its rear end abuts against the flange portion 33a of the spring retaining cylinder 33, which abuts against the stopper wall 29.

Spring retaining hole 31 of front plunger 16+. The front majority portion 31a is enlarged in diameter so that the entire front return spring 3o1 can be reliably accommodated when the plunger 161 moves forward until it comes into contact with the front end wall of the first hole 10a. Such widening may be stepped or tapered as shown in FIG.

As shown in FIGS. 2(a), 3, and 7, the front bulkhead collar 12. A plurality of notches n are formed at equal intervals on the circumference of the flange portion C. Further, a plurality of radial grooves 341 are formed on the front surface of the large diameter front part a so as to cut into each notch part n, and the valley grooves 341 are connected to the front annular oil chamber 11 through each notch part n.
．． It will be communicated to. From these radial grooves 34i to the front hydraulic chamber 1
Rubber front one-way seal member 35. which allows flow of hydraulic fluid only to 71. is attached to the front seal chamber g+, and its inner peripheral lip h is attached to the front plunger 16. The outer circumferential knob j is in close contact with the inner circumferential surface of the front seal chamber ε, respectively. Further, in the front seal chamber g, a front one-way seal member 35. A retainer 361 is attached to the front side and an annular spacer 37 is attached to the rear side so as to sandwich the retainer 361 and the annular spacer 37, respectively. Retainer 36. consists of a short cylindrical portion 36a surrounding the inner peripheral lip h of the front one-way seal member 35I, and a flange portion 36b formed at the front edge of the short cylindrical portion 36a.

On the front side of the front one-way seal member 351, a plurality of thin plate-like elastic protrusions l are formed on the annular base part k at equal intervals on the circumference so as to connect the bases of the inner and outer lips h and j. . Each elastic protrusion f is connected to a retainer 36. The flange portion 36b is in contact with the rear end surface of the short cylindrical portion 36a of
The spacer 37. The rear surface of the front bulkhead collar 12. is polymerized in front of the In this state, a predetermined distance 0 is formed between the outer circumferential knob j and the flange portion 36b.

Each elastic protrusion 2 has a front one-way seal member 35. when the front plunger 16+ moves forward. maintains its normal configuration so as to prevent the forward movement of the front plunger 161, and also holds the front hydraulic chamber 17. The front one-way seal member 35. It is compressed and deformed to allow the forward movement of the body.

Front plunger 16. When it is at the predetermined retraction limit, the front one-way seal member 35. Immediately after the inner circumferential lip h of the radial groove 34. A front relief boat 381 is bored to communicate between the spring holding hole 31+ and the spring holding hole 31+.

Further, a sealing member 391 that brings the inner peripheral lip into close contact with the outer peripheral surface of the front plunger 161 is attached to the front end of the through hole 13C of the sleeve 13, and the front partition collar 12. Similarly, a plurality of notches n are formed at equal intervals on the circumference in the flange portion C of the rear partition wall collar 12□. In addition, a plurality of radial grooves 34 are formed on the front surface of the large diameter front part a so as to cut into each notch part n.
□ is formed, and the valley groove 34 □ communicates with the rear annular oil chamber 11 □ via each notch n. Rubber rear-direction seal members 35 , which allow flow of hydraulic fluid only from these radial grooves 34 □ to the long axial grooves 23 of the sleeve 13 . is attached to the rear seal chamber g2, its inner peripheral lip h is in close contact with the outer peripheral surface of the rear plunge +16°, and its outer peripheral tongue j is in close contact with the inner peripheral surface of the rear seal chamber g2. Also, there is a rear one-way seal member 35 in the rear seal chamber gt! A retainer 36□ is placed on the front side to sandwich the , and an annular spacer 37g is placed on the rear side.
are installed respectively. The structures of the retainer 36I and the rear one-way seal member 35□ are the same as those on the front side, so the same parts are given the same reference numerals and the explanation will be omitted.

Rear plunger 16. When it is at the predetermined retraction limit, the rear relief boat 38. which communicates between the radial groove 34□ and the spring holding hole 31□ immediately after the inner peripheral lip h of the rear one-way seal member 35g. is drilled.

Further, a sealing member 39 □ is installed in the recess 15 of the bearing 14 to bring the inner lip into close contact with the outer peripheral surface of the rear plunger 162 .

Now, the front and rear bulkhead collars 12. ．． The radial inner end d of each radial groove 345, 34g in 12□ is as shown in FIG.
a), each spacer 37. as clearly shown in FIG. ,37
! It ends at a position radially outward from the inner circumferential edge e of.

Next, the mounting structure of the bearing 14 to the cylinder body 1 will be explained with reference to FIG. 1 and FIGS. 5 to 7.

In the cylinder body 1, the rear end opening of the third hole 10c is formed as a large-diameter annular step 40, and the step 40 has a plurality of inward protrusions 41 extending radially inward at the rear end edge of the step 40. Formed at even intervals. The tip surface of each inward protrusion 41 is the third
Located on the extended inner peripheral surface of hole 10c! do.

The bearing 14 is a cylindrical portion 4 that supports the rear plunger 16□.
2 and a plurality of outward protrusions 43 formed at the rear end and directed radially outward, each outward protrusion 43 being able to be loosely inserted into a notch 46 between adjacent inward protrusions 41. It has become.

The cylindrical portion 42 of the bearing 14 is rotatably fitted into the third hole 10e together with a ring-shaped seal member 45 attached to an annular groove 44 on the outer peripheral surface of the cylindrical portion 42, and at this time, each outward protrusion 43 is inserted into each notch. It passes through section 46. Then, the bearing 14 is inserted into the third hole 10 by engaging the tool with the pair of engagement holes 47 opened on the rear end surface.
When rotated about the c-axis, each outward protrusion 43 is engaged with the front surface of each inward protrusion 41.

The rotation of the bearing 14 is prevented by a sleeve spring 48, and the stop spring 48 is connected to opposing pieces 49a and 49b.
The tJ-shaped portion 49 is biased in the direction of separating the opposing pieces 49a and 49b, and the opposing pieces 49a are
, 49b, an engagement piece 50a bent at an acute angle to the outside thereof;
50b and more.

The U-shaped portion 49 has one cutout portion 46 and both opposing pieces 4 thereof.
9a and 49b are bent in a direction toward each other, and the distal ends of both engaging pieces 49a and 49b engage with the opposing surfaces of adjacent outward protrusions 43 and the front surfaces of adjacent inward protrusions 41, respectively. do. This engagement prevents the stop spring 48 from falling off from the notch 46 and also prevents the bearing 14 from rotating.

Next, the operation of this embodiment will be explained.

Now, if the negative pressure booster B is activated to advance its output rod 19, it will be pressed by it and both plungers 16. ,16
□ corresponds to the return springs 30, . Move forward while compressing 302. In this case, since the cylindrical portion 42 of the bearing 14 is fitted into the third hole 10c, the coaxiality of the bearing 14 with respect to the sleeve 13 is easily ensured in terms of processing accuracy, and therefore the sliding of the rear plunger 16□ movement can be carried out smoothly.

and front relief boat 38. moves forward of the front one-way seal member 351, the front plunger 16.
Hydraulic pressure is generated in the front hydraulic chamber 17 according to the forward force of the rear relief boat 382, and the rear one-way seal member 3
5. , the rear plunger 16. Hydraulic pressure is generated in the rear hydraulic chamber 17□ according to the forward force of the rear hydraulic chamber 17□.

The hydraulic pressure generated in the front and rear hydraulic chambers 17+ and 17g is outputted from the corresponding output boats 1B+ and 18z, and
The system's hydraulic brakes can be operated at the same time to apply braking to the vehicle.

Before this, the rear plunger 16. ．． When the 16□ moves forward, each elastic protrusion β contacts the front wall m of the front and rear seal chambers g+ and gt via the retainers 36+ and 36z, so that the front and rear seal chambers g+ and gt are in contact with each other.
The rear one-way seal member 35°, 35t is attached to each plunger 1.
6. , 162, and the one-way seal members 35+, 35□ do not move backward.

This makes it possible to avoid a delay in the pressure increase response of the rear hydraulic chambers IL and IL.

When the negative pressure booster B is returned to the inoperative state in order to release the braking, each plunger 16+, 16□ is activated by the corresponding return spring 3.
The repulsive forces of 0+ and 30g return each to the predetermined retraction limit, but if the pressure in each hydraulic chamber IL and 17g is reduced during the retraction process, the corresponding one-way seal member 351° is removed as shown in FIG. 2(b). 35 moves forward with the annular spacer 371.37□ to fill the gap 0 while compressing and deforming each elastic protrusion 2 due to the pressure difference between the front and rear, and each annular spacer 37
,．． A relatively wide supply oil passage q is formed between 37□ and each bulkhead collar 121.12□, and at the same time, the inner circumferential lip h is radially outward due to the pressure difference and the diameter expansion force caused by the deformation of each elastic protrusion p. The first oil sump 8. Hydraulic oil of through hole 91
, front annular oil chamber 1IIs radial groove 346, supply oil passage q
and front one-way seal member 35. Hydraulic oil in the second oil reservoir 8t is supplied to the front hydraulic chamber 171 through the inside of the inner circumferential lip h, and the hydraulic oil in the second oil reservoir 8t is supplied to the through hole 9□, the rear annular oil chamber 112, the radial groove 34□, the supply oil passage, and the rear hydraulic oil chamber 171. Directional seal member 35g
It is supplied to the rear hydraulic chamber 17□ through the inside of the inner circumferential lip h and the long axial groove 23g. These supply oil passages q
Front and rear hydraulic chambers 17I, 17! It is possible to improve the efficiency of replenishing hydraulic oil to.

During this hydraulic oil replenishment, each hydraulic chamber 17. , 17□, the excess amount is transferred to each plunger 1.
6. ,16. When the oil returns to the backward limit, the oil is discharged from each relief port 3B, , 3B□ to the oil reservoir 81.8□ side.

By the way, the front and rear hydraulic chambers 17. ．． As the pressure of 17□ increases, the front and rear one-way seal members 35+ and 352 close to the spacer 3.
71.37g through front and rear bulkhead collars 12. ．． 12□
, but as described above, each radial groove 34. ,34
The inner end d of □ is each spacer 37. , 37□, the front and rear one-way seal members 35. ．． The rear inner peripheral edge of 35□ is connected to each radial groove 34
1.34□, and as a result, the front and rear one-way seal members 35. ．． 35. Improved durability of front and rear plungers 16. ．． 1e2 can move forward and backward smoothly.

When performing maintenance on the master cylinder M, the bearing 14 can be removed from the cylinder body 1 by removing the stop spring 48 and then rotating the bearing 14 so that the inward protrusions 41 and the outward protrusions 43 are aligned. Moreover, since the bearing 14 can be easily installed, the workability is improved.

8th. FIG. 9 shows another embodiment, in which an outer peripheral lip j of the front one-way seal member 351 is used instead of the thin plate-like elastic protrusion l.
A plurality of hemispherical elastic protrusions are provided on the front end surface at equal intervals on the circumference.Similar hemispherical elastic protrusions r are naturally provided on the rear one-way seal member 35!.These hemispherical elastic protrusions r functions similarly to the thin plate-like elastic protrusion 2.

C3 Effects of the Invention According to the present invention, by providing the one-way seal member with an elastic protrusion of a specific configuration, it is possible to avoid a delay in the pressure increase response of the hydraulic chamber, and to improve the efficiency of supplying hydraulic oil to the hydraulic chamber. I can do it.

[Brief explanation of the drawing]

1 to 7 show one embodiment of the present invention, FIG. 1 is a longitudinal cross-sectional side view of a tandem type master cylinder, and FIG.
) is a partially enlarged view of Figure 1, Figure 2(b) is Figure 2(a)
3 is a sectional view taken along the line m-■ in FIG. 1, FIG. 4 is a front view of the front one-way seal member, and FIG. 5 is a sectional view taken along the line 6 is a sectional view taken along the line Vl-Vl in FIG. 5, FIG. 7 is an exploded perspective view of the main parts, and FIG. Fig. 9 shows another embodiment of the present invention, Fig. 8 is a partially enlarged longitudinal sectional side view corresponding to Fig. 2(a), and Fig. 9 is a front view of the front one-way seal member. . H...Cylinder hole, M...Tandem type master cylinder, gl, gt...Front and rear seal chambers, h...Inner peripheral lip, 1. r... Elastic protrusion, 1... Cylinder body, 81, 8□... 1st. 2nd oil sump, 121.12□...front, rear bulkhead collar, 161
．． 16□・・・Front, rear plunger, 171.172・
...Front and rear hydraulic chambers, 30. ．． 30. ...Front and rear return springs, 35. ．． 35! ...Front and rear one-way seal members, 3B,, 3B□...Front and rear relief ports Figure 2, Figure 3, Figure 4, Figure 5, Figure 6

Claims (1)

[Claims] a cylinder body provided with an oil reservoir; a partition collar fitted into a cylinder hole of the cylinder body; a plunger defining a communicating seal chamber and a hydraulic chamber communicating with the front part of the seal chamber; a return spring that urges the plunger in a backward direction; a one-way seal member with a circumferential lip brought into close contact with the plunger, and a relief boat is bored in the plunger that communicates with the hydraulic chamber immediately after the inner circumferential lip of the one-way seal member when the plunger is at a predetermined retraction limit. In the master cylinder, the front side of the one-way seal member is in contact with the seal chamber wall, and when the plunger moves forward, the one-way seal member is held in a retreat position, but when the plunger moves back, the pressure in the hydraulic chamber is reduced. The master cylinder is characterized in that it is provided with an elastic protrusion that allows the one-way seal member to move forward as the one-way seal member moves forward.