JPS63235150A - Assembly of master cylinder and negative pressure booster - Google Patents

Abstract

PURPOSE:To prevent falling of sleeve or piston, when a booster section is dismantled, by providing the piston slidably on the inner circumferential face of the sleeve fitted over a master cylinder through a retreat limit stopper, and arranging a seal member lip at the end of an annular sleeve fixing screw. CONSTITUTION:Cylinder body 1 of a master cylinder M and the shell 2 of a negative pressure booster B are coupled through a seal member 21, then a sleeve 13 is fitted in a cylinder hole 10 of the cylinder body 1 and a piston 16 is provided slidably on the inner circumferential face of the sleeve 13 with the rear end thereof connected to the output rod 19 of the negative pressure booster. Stoppers 28, 29 for limiting retreat of the piston 16 are provided to the sleeve 13 which is stopped by an annular stopping screw 15, and the lip 21a of the seal member 21 is arranged at the rear end. Consequently, falling of the sleeve 13 and the piston 16 is prevented when the negative pressure booster B and the master cylinder M are dismantled.

Description

Detailed Description of the Invention A1 Object of the Invention (11 Industrial Field of Application) The present invention relates to a cylinder main body of a master cylinder and a booster shell of a negative pressure booster, which are connected to each other with a sealing member sandwiched between them. The rear end of the piston that can slide in the cylinder hole of the main body is inserted into the booster shell so as to be connected to the output rod of the negative pressure booster, and the lip of the sealing member is brought into close contact with the outer peripheral surface of the piston. The present invention relates to a cylinder and negative pressure booster assembly.

(2) Prior Art Such an assembly is conventionally known, as described in, for example, Japanese Utility Model Application Publication No. 59-56158.

(3) Problems to be Solved by the Invention In such a conventional assembly, an annular stopper member for regulating the retraction limit of the piston is fitted into the rear end of the cylinder body,
To prevent this stopper member from coming off, the rear end is held down by a booster shell, so when the cylinder body and booster shell are separated for maintenance, the stopper member will immediately fall off from the cylinder body together with the piston, etc., damaging them. There is a risk that this will happen.

Therefore, in order to prevent the stopper member from falling off, if it is screwed onto the cylinder body, there is a risk that the rotational force will be transmitted to the piston and twist or damage the sealing member around the piston. There is.

The present invention has been made in view of these points, and can prevent the piston from falling off even when the cylinder body and booster shell are separated, and also prevents the seal member around the piston from being twisted when disassembling and assembling the master cylinder. It is an object of the present invention to provide an assembly of the master cylinder and a negative pressure booster that does not cause damage and is compact.

B6 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a sleeve that is fitted into a cylinder hole of a cylinder body, and a sleeve that is slidably fitted on the inner circumferential surface of the sleeve. A stopper means for regulating the retraction limit of the piston is provided between the piston, an annular retaining screw surrounding the piston is screwed to fix the sleeve to the rear opening of the cylinder hole, and a stopper means is provided at the rear end of the retaining screw. It is characterized in that the lip of the sealing member is accommodated in the formed tool engagement recess.

(2) Effect According to the above configuration, even if the cylinder body and the booster shell are separated, the sleeve and piston do not fall off from the cylinder body unless the retaining screw is removed from the cylinder body.

When the cap screw is attached or detached, its rotational force is not transmitted to the piston, and therefore the sealing member around the piston is not twisted or damaged.

Moreover, the tool engagement recess at the rear end of the cap screw also serves as a housing recess for the lip of the sealing member interposed between the cylinder body and the booster shell, so the space occupied by the lip can be specially reduced between the cylinder body and the booster shell. There is no need to provide the same, and the overall length of the assembly can be reduced accordingly.

(3) Examples Embodiments of the present invention will be described below with reference to the drawings.

First, in FIGS. 1 to 3 showing a first embodiment of the present invention, M is a tandem master cylinder for a two-system hydraulic brake of an automobile, and B is a negative pressure booth cylinder operated by a brake pedal (not shown). The rear end of the cylinder body 1 of the former M and the front wall of the booster shell 2 of the latter B are connected to each other by bolts (not shown).

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 to it. The main oil reservoir 4 has a cap 5 at its upper end, and is equipped with a known oil level sensor 6 supported by the cap 5 inside.

The inside of the auxiliary oil reservoir 3 is divided into first and second oil reservoirs 8 by a partition wall 'l. ．． These oil reservoirs 81° and 8 □ are each supplied with hydraulic oil from the main oil reservoir 4.

The first and second oil reservoirs 80, 8□ are through holes 91.9□, respectively.
It communicates with the cylinder hole 10 of the cylinder body 1 via. The cylinder hole 10 includes a first hole 10a with a closed front end, and a second hole 10 which has a larger diameter than the first hole 10a and continues at the rear end.
b, a third hole with a larger diameter than this second hole tob and connected to the rear end
It consists of a hole 10c, and a fourth hole 10d that has a larger diameter than the third hole 10c and is connected to the rear end and has an open rear end, and a front partition wall is provided at the step between the second hole 10b and the third hole 10c. The collar 121 is fitted, and the sleeve 13 that abuts the rear surface of this collar 121 is fitted over the third hole 10c and the fourth hole 10d, and the rear partition collar 12□ and this collar 12 that abut the rear end of this sleeve 13 are fitted. □ The bearing 14 that comes into contact with the rear surface is fitted into the fourth hole 10d, and the bearing 1
An annular retaining screw 15 that presses the rear surface of the fourth hole 10d is screwed into the rear opening of the fourth hole 10d.

A tool engagement recess 4 with a hexagonal cross section is provided on the rear end surface of the cap screw 15.
0 is formed, and a tool (
(not shown), the cap screw 15 is attached and detached.

A plurality of radial grooves 41 are formed in at least one of the contact surfaces of the bearing 14 and the cap screw 15, and the grooves 41 are formed in an annular groove 42 on the inner peripheral surface of the fourth hole 10d, and in a lower part of the annular groove 42. It communicates with the outside through a continuous horizontal hole 43 of the cylinder body 1 and a discharge groove 44 formed between the lower joint surfaces of the cylinder body 1 and the booth shell 2. Therefore, even if the hydraulic oil in the cylinder body 1 should leak from the bearing 14, it can be quickly discharged to the outside from the drain groove 44 and the oil can be prevented from entering into the booster shell 2.

The sleeve 13 defines, by its outer peripheral surface, a front annular oil chamber 11+ connected to the front passage hole 9I as the third hole 10c, and a rear annular oil chamber 11x connected to the passage hole 9□ as the fourth hole 10.
d.

The sleeve I3 has a pair of front and rear pistons 16. .

162 is slid, and the front piston 161 and the first hole 10a
A front hydraulic chamber 171 is defined between the front end walls of both pistons 16. , 16□ defines a rear hydraulic chamber 17□. These hydraulic chambers 17. ．． 17□ are the front and rear output ports 18. of the cylinder body 1. ．． It is communicated with each of the two brake hydraulic circuits via 18□.

The rear end of the rear piston 16□ passes through the rear bulkhead collar 12□ and the bearing 14, extends to the rear of the cylinder body 1, and further penetrates the front wall of the booster shell 2 to connect to the negative pressure booster B.
It is connected to the output rod 19 of.

A sealing member 21 is sandwiched between the cylinder body 1 and the booster shell 2 in order to prevent the internal negative pressure from leaking from the through hole 20 of the booster shell 2 through which the rear piston 16g passes.

This sealing member 21 is provided with a pair of front and rear lips 21a and 21b that are in close contact with the outer peripheral surface of the rear piston 16□, and the front lip 21a extends forward from the rear lip 21b to form the tool engagement recess of the cap screw 15. 40 accepted.

Rear hydraulic chamber 17. In order to communicate between the rear output boat 18□ and the rear output boat 18□, the sleeve 13 is provided with an axial groove 23 running on its inner circumference, a horizontal hole 24, and an annular groove 25 running on its outer circumference.

There is one cut 27 in the outer circumferential groove 26 of the rear piston 16g.
A stopper ring 28 having a diameter is attached. This stopper ring 2
8 includes one or more protrusions 28a that protrude outward from the outer peripheral surface of the rear piston 16□, and this protrusion 28a
is engaged with the axial groove 23 of the sleeve 13. The rear end of the axial groove 23 is closed by a stopper wall 29 that is integral with the sleeve 13, and when the projection 28a comes into contact with the stopper wall 29, a predetermined retreat limit of the rear piston 16□ is regulated. Therefore, stopper ring 2
8 and the stopper wall 29 constitute the stopper means of the present invention.

Rear piston 16. A bottomed spring holding hole 31□ for receiving a rear return spring 30□ that urges the piston 16□ in the backward direction is provided in the front end surface of the piston 16□.

Further, a guide bolt 32□ that protrudes in the axial direction by a certain length from the end wall of the spring holding hole 312 is screwed onto the rear piston 16□, and a rear return spring 3oz.
A hat-shaped spring holding cylinder 33 supporting the front end of the tube. are slidably connected within a certain stroke range.

The rear bulkhead collar 12□ has a radial groove 34 that connects to the rear annular oil chamber lig! is formed and allows oil to flow from this groove 34 to the axial groove 23 of the sleeve 13.
Directional seal member 35! However, the lip is connected to the rear piston 1.
It is attached to the rear end of the sleeve 13 in close contact with the outer peripheral surface of the sleeve 6g.

Also, a rear one-way seal member 3 is provided at the rear end of the sleeve 13.
5.0 spacer 37 inserted between the retainer 36t that holds the front end, the rear one-way seal member 351, and the rear partition collar 12□. is installed.

The rear piston 16□ has a radial groove 34 immediately after the rear one-way seal member 35□ when it is at a predetermined retraction limit.
A rear relief boat 38□ is bored to communicate between the spring holding hole 31 and the spring holding hole 31.

Further, a seal member 39g is attached to the bearing 14 to bring the lip into close contact with the outer peripheral surface of the rear piston 16g.

On the other hand, the front piston 16. The front end of the front bulkhead collar 1
2. A bottomed spring holding hole 311 is provided on the front end surface of the first hole 10a to receive a front return spring 301 that urges the front piston 16t in the backward direction. The front piston 161 also has a guide pole that protrudes a certain length in the axial direction from the end wall of the spring holding hole 31t.
The guide bolt 321 has a hat-shaped spring holding cylinder 31 that supports the front end of the front return spring 301.
．． are rubbed together.

Front piston 16. The predetermined retraction limit of is regulated by the rear end coming into contact with the spring holding cylinder 33z in the extended position. In this case, the front return spring 30 is the spring holding cylinder 33! The set load is set to be weaker than that of the rear return spring 30t so as to keep the spring at a predetermined extended position.

The front bulkhead collar 121 has a radial groove 34 that is connected to the front annular oil chamber 11 . is provided, and from this groove 34+ the front hydraulic chamber 17. The front one-way seal member 35. allows oil to flow only to the front one-way seal member 35. but its lip is connected to the front piston 16
It is attached to the second hole 10b in close contact with the outer circumferential surface of I.

The second hole 10b also includes a front one-way seal member 35.
retainer 36. which holds the front end of the retainer 36. and the seal member 3
5. and the spacer 3 inserted between the front bulkhead collar IL.
7. is installed.

The front piston 161 has a front relief boat 38. which communicates between the radial groove 34+ and the spring retaining hole 311 when the front piston 161 is at a predetermined retraction limit. is penetrated.

Further, a sealing member 39 is attached to the front end of the sleeve 13 to bring its lip into close contact with the outer peripheral surface of the front piston 16.

Here, the front and rear pistons 16. ．． 16□ respectively occupy a predetermined retracted position, the front one-way seal member 35. of the front piston 161. If the forward protrusion length from the piston is 11, and the distance between the pistons 16+ and 16t is 12, then 2, > 2° is set. In this way, the rear return spring 30□
Due to damage etc., the front piston 161 is replaced by the rear piston 16.
Even if the front one-way seal member 35. The front piston 161 can be prevented from being pulled out rearward.

Next, the operation of this embodiment will be explained.

Now, if you activate the negative pressure booster B and move its output rod 19 forward, it will press it and both pistons 16 = 16 g.
move forward while compressing the corresponding return springs 3°1.30□. and front piston 16. The relief boat 381 is connected to the front one-way seal member 35. When moving forward of the front piston 16. Hydraulic pressure is generated in the front hydraulic chamber 17 according to the forward force of the rear piston 162.
The relief boat 38□ is the rear one-way seal member 35,
When moving forward, hydraulic pressure is generated in the rear hydraulic chamber 17□ in response to the forward force of the rear piston 16□.

Thus the front and rear hydraulic chambers 17. ．． The hydraulic pressure generated in 17□ is transferred to the corresponding output boat 18. , L8□, it is possible to operate two systems of hydraulic brakes at the same time and apply braking to the automobile.

In order to release the brake, if the negative pressure booster B is returned to the inactive state, each piston 16. ,16. is the corresponding return spring 30
．． ．． Each hydraulic chamber 17. is returned to its predetermined retraction limit by the repulsive force of 30□. , 17□, the corresponding one-way seal member 35. , 35□ lips are respectively hydraulic chamber 171.17 due to the pressure difference between front and rear.
Because it bends to the □ side, the first oil sump 8. Hydraulic oil flows through the through hole 91,
Front annular oil chamber 111, radial groove 34. and front one-way seal member 35. through the inside of the lip of the front hydraulic chamber 17
The hydraulic oil in the second oil reservoir 8□ is supplied to the through hole 9t.
, the rear hydraulic chamber 17 through the rear annular oil chamber 11□, the radial groove 34□, the inside of the lip of the rear one-way seal member 35□, and the axial groove 23.

At this time, if excess hydraulic oil is supplied to each hydraulic chamber 171.17□, the excess amount is supplied to each piston 16. ．． IL
When the boat returns to its retreat limit, each relief boat 38. ,38
The oil is discharged from □ to the oil sump 81.8□ side.

By the way, the protrusion 28a of the stopper ring 28 attached to the rear piston 16□ only moves forward in the axial groove 23 of the sleeve 13 when the piston 16□ moves forward.
The piston 16□ does not move forward in any way, and when the piston 16□ retreats, it comes into contact with the stopper wall 29 of the sleeve 13 to restrict the backward limit of the piston 16g. In this way, the restriction of the retraction limit of the rear histone 16□ is performed within the cylinder hole 10, so that the cylinder body 1 and the bearing 14 can be shortened so as to expose the rear end portion of the rear piston 16□.

Moreover, since the front lip 21a of the seal member 21 is received in the tool engagement recess 40 of the cap screw 15, there is no need to provide a special space for the lip 21a between the cylinder body 1 and the booster shell 2. The overall length of the assembly can be reduced accordingly.

Further, even if the cylinder body l and booster shell 2 are separated for maintenance, for example, unless the retaining screw 15 is removed, the sleeve 13 and the front and rear pistons 16. ．． 1
6! cannot be taken out from the cylinder hole 10, thus preventing them from falling off.

Also, when rotating the cap screw 15 for attachment/detachment,
Since the rotational force is not transmitted to the rear piston tit,
There is no possibility of twisting or damaging the seal member around the rear piston 162.

FIG. 4 shows a second embodiment of the present invention, which has the same structure as the previous embodiment except that the bearing 14 and the bulkhead collar 12□ are integrated. are given the same symbols.

C1 Effects of the Invention As described above, according to the present invention, the cylinder body
- A stopper means for regulating the retraction limit of the piston is provided between the sleeve that is fitted into the cylinder hole and the piston that is slid on the inner peripheral surface of the sleeve, and the annular retaining screw surrounding the piston is inserted into the cylinder hole. The sleeve is screwed into the rear opening of the cap screw to fix it, and the lip of the sealing member is accommodated in the four tool retaining parts formed at the rear end of the presser screw, so even if the cylinder body and booster shell are separated, the sleeve remains intact. ,
To prevent a piston or the like from falling off from a cylinder body using a retaining screw, and to prevent twisting or damage to a sealing member around the piston by not applying rotational force to the piston when attaching or removing the retaining screw. is possible,
Furthermore, since the tool engagement recess of the presser foot serves as the accommodation recess for the lip of the seal member, the overall length of the assembly can be shortened, contributing to its compactness.

[Brief explanation of the drawing]

1 to 3 show a first embodiment of the present invention, in which FIG. 1 is a longitudinal cross-sectional side view of an assembly of a master cylinder and a negative pressure booster, and FIG. 2 is a line taken along the line ■-■ in FIG. 3 is an exploded perspective view of the main part of FIG. 1, and FIG. 4 is a vertical sectional side view of the main part of the second embodiment of the present invention. B...Negative pressure booster, M...Master cylinder...
Cylinder body, 2... Booster shell, IO... Cylinder hole, 13... Sleeve, 15... Holding screw,
16i... Piston, 21... Seal member, 21a
...Lip, 28.29...Stopper ring and stopper wall constituting stopper means, 40...Tool engagement recess Fig. 2

Claims (1)

[Claims] The cylinder body of the master cylinder and the booster shell of the negative pressure booster are connected with a seal member sandwiched between them, and the rear end of the piston that can slide in the cylinder hole of the cylinder body is connected to the output rod of the negative pressure booster. In an assembly of a master cylinder and a negative pressure booster, the sleeve is fitted into a cylinder hole of a cylinder body, and the lip of the seal member is brought into close contact with the outer peripheral surface of the piston. A stopper means for regulating the retraction limit of the piston is provided between the piston and the piston that slides on the inner peripheral surface of the sleeve, and an annular retaining screw surrounding the piston is used to fix the sleeve to the rear opening of the cylinder hole. An assembly of a master cylinder and a negative pressure booster, characterized in that the lip of a sealing member is accommodated in a tool engaging recess formed at the rear end of the cap screw.