JPS63219467A - master cylinder - Google Patents

Abstract

PURPOSE:To shorten the cylinder main body by inserting a plunger in a sleeve which is inserted to a cylinder hole of a master cylinder, and furnishing a stopper to regulate the retreating limit of the plunger between the sleeve and the plunger. CONSTITUTION:In a tandem type master cylinder M connected to a negative pressure booster B, a partition wall collar 121 is inserted to a step between the second and the third holes 20b and 10c of a cylinder hole 10 with steps, of a cylinder main body 1, and a sleeve 13 is inserted connecting to the rear side of the collar 121. And a pair of the front side and the rear plungers 161 and 162 are installed slidable to the sleeve 13. In this case, at the outer periph eral groove 26 of the rear side plunger 162, a stopper ring 28 is furnished, the projection 28a of which is geared to an axial groove 23 of the sleeve 13. The rear end of the axial groove 23 is closed at a stopper wall 29, and a specific retreating limit of the plunger 162 is regulated by contacting the projection 28a to the stopper wall 29.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention provides a method for making a plunger inserted into a cylinder hole of a cylinder body slidable by a bearing fixed to the rear end of the cylinder body. This invention relates to an improvement of a master cylinder supported by a cylinder.

(2) Prior art This type of master cylinder is known, for example, from Japanese Patent Application Laid-Open No. 58-1695.
This is already known as disclosed in Publication No. 2.

(3) Problems to be Solved by the Invention In conventional master cylinders of this kind, in order to restrict the retraction limit of the plunger, a cylindrical stopper member that receives the rear end surface of the plunger is mounted on a bearing or at the rear end of the cylinder body. Since the rear end of the bearing or cylinder body must be extended backwards to the rear end of the plunger in the retracted position, this poses an obstacle to converting the cylinder body or bearing into a compact one. It becomes.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a master cylinder that can regulate the retraction limit of the plunger while making the cylinder body and bearing more compact.

B0 Structure of the Invention (Means for Solving Problem 11) In order to achieve the above object, the present invention includes a plunger that slides into a sleeve fitted into a cylinder hole adjacent to the front of a bearing, and The present invention is characterized in that a stopper means is provided between the plungers to restrict the retraction limit of the plungers.

(2) Effect According to the above configuration, the retraction limit of the plunger is regulated by the stopper means provided between the sleeve in the cylinder hole and the plunger, so that the cylinder body and the bearing do not expose the rear end of the plunger. It can be made as short as possible.

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

1 and 2, 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 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 separated by a partition wall 7 into first and second oil reservoirs 8.
These oil reservoirs 81° and 8 □ are each supplied with hydraulic oil from the main oil reservoir 4.

The first and second oil reservoirs 81.8□ are each through holes 91.9z
It communicates with the cylinder hole lO of the cylinder body 1 via. The cylinder hole 10 includes a first hole 10a whose front end is closed and a second hole 10b which has a larger diameter than the first hole 10a and which is connected to the rear end.
, a third hole 10c having a larger diameter than this second hole 10b and continuous to the rear end, and a fourth hole 10d having a larger diameter than this third hole 10c and continuous to the rear end and having an open rear end. A front partition collar 12. is provided at the step between the second hole 10b and the third hole 100. is fitted, and the sleeve 13 that abuts the rear surface of this collar 121 is fitted across the third hole 10C and the fourth hole 10d, and the rear bulkhead collar 128 that abuts the rear end of this sleeve 13 and the rear surface of this collar 12□. The bearing 14 that abuts is fitted into the fourth hole 10d, and the bearing 14
An annular retaining screw 15 for pressing the rear surface is screwed from the rear end of the fourth hole 10d.

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

The sleeve 13 has a pair of front and rear plungers 16I and 16□.
is slid and the front plunger 16. A front hydraulic chamber 17 is defined between the first hole 10a and the front end wall of the first hole 10a, and both plungers 1
6. , 16□ defines a rear hydraulic chamber 17□. These hydraulic chambers 17. ．． 17t is communicated with each of the two brake hydraulic circuits via the front and rear output boats 181.18□ of the cylinder body 1. - The rear end of the rear plunger 16□ is connected to the rear bulkhead collar 12z.
and extends to the rear of the cylinder body 1 through the bearing 14,
Furthermore, it passes through the front wall of the booster shell 2 and is connected to the output rod 19 of the negative pressure booster B.

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

In order to communicate between the rear hydraulic chamber 17□ and the rear output boat L8i, the sleeve 13 is provided with an axial groove 23 running on its inner peripheral surface, a horizontal hole 24, and an annular groove 25 running on its outer peripheral surface.

Rear plunger 16. There is one cut 2 in the outer circumferential groove 26 of
A stopper ring 28 having a diameter of 7 is attached.

The stopper ring 28 includes one or more protrusions 28a that protrude outward from the outer peripheral surface of the rear plunger 16g, and the protrusions 28a are connected to the axial groove 28 of the sleeve 13.
(See Figure 3).

The rear end of the axial groove 23 is closed by a stopper wall 29 integrated with the sleeve 13, and when the projection 28a comes into contact with this stopper wall 29, the rear plunger 1
A predetermined retreat limit of 6t is regulated. Therefore, the stopper ring 28 and the stopper wall 29 constitute the stopper means of the present invention.

On the front end surface of the rear plunger 16□, the plunger 16
A bottomed spring holding hole 31g is provided to receive a rear return spring 30□ that urges □ in the backward direction. Further, a guide bolt 32□ that protrudes in the axial direction by a certain length from the end wall of the spring holding hole 313 is screwed onto the rear plunger 16□, and this guide bolt 32□ supports the front end of the rear return spring 30z. A hat-shaped spring holding cylinder 33 is slidably connected within a certain stroke range.

A radial groove 34g connected to the rear annular oil chamber 11□ is formed in the rear bulkhead collar 12□, and a rear one-way seal member 35□ allows oil to flow from this groove 342 to the axial groove 23 of the sleeve 13. Connect the lip to the rear plunger 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.
A retainer 36° that holds the front end of 5□ and a rear one-way seal member 35! and a spacer 37 inserted between the rear bulkhead collar 12□. is installed.

Rear plunger 16! When it is at the predetermined retraction limit, the radial groove 3 is inserted immediately after the rear one-way seal member 35□.
4. A rear relief boat 38t is bored to communicate between the spring holding hole 31 and the spring holding hole 31.

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

On the other hand, the front end of the front plunger 161 is connected to the front bulkhead collar 12. A bottomed spring retaining hole 31. which extends through the first hole 10a to the first hole 10a and receives a front return spring 301 that biases the front plunger 16° in the backward direction.
is provided. Also, the front plunger 16. has a spring holding hole 31. A guide bolt 321 is threadedly attached to the guide bolt 32I, which protrudes in the axial direction by a certain length from the end wall of the front return spring 30. A Huff-shaped spring holding cylinder 331 that supports the front end of the spring holding cylinder 331 is slidably fitted.

A predetermined retraction limit of the front plunger 161 is regulated by the rear end coming into contact with the spring holding cylinder 33□ in the extended position. In this case, the front return spring 30. The set load of the rear return spring 30 is set to be weaker than that of the rear return spring 30 so as to keep the spring holding cylinder 33□ in a predetermined extended position.

Front bulkhead collar 12. is provided with a radial groove 341 that continues to the front annular oil chamber 111, and this groove 34. From 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 attached to the front plunger 1
6. It is attached to the second hole lOb in close contact with the outer peripheral surface of.

The second hole 10b also includes a front one-way seal member 35.
A spacer 37. is inserted between the seal member 35+ and the front partition collar 12I. is installed.

Front plunger 16. A front relief hole 1-3L is bored in the front relief port 1-3L that communicates between the radial groove 341 and the spring holding hole 311 when the spring is at a predetermined retraction limit.

Further, a front plunger 161 is provided at the front end of the sleeve 13.
A seal member 39 that brings the lip into close contact with the outer peripheral surface of the seal member 39. is installed.

Here, when the front and rear plungers IL, 16□ respectively occupy predetermined retracted positions, the front plunger 16. Front one-way seal member 35. The forward protrusion length from! 1,
Both plungers16. , 16□ is set as i2, J, > 1°. In this way, the rear return spring 30□
The front plunger 16. was damaged due to damage etc. Even if the front one-way seal member 35. is abnormally retreated until it contacts the front end of the rear plunger 16□, From the front plunger 16. can be prevented from being pulled out backwards.

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, . It moves forward while compressing 30t. and front plunger 16. Nori reef boat 38. is the front one-way seal member 35. When moving forward of the front plunger 16. The front hydraulic chamber 17. When the relief boat 38t of the rear plunger 16□ moves to the front of the rear one-way seal member 35□, hydraulic pressure is generated in the rear hydraulic chamber 17□ according to the forward force of the rear plunger 16g.

The hydraulic pressure generated in the front and rear hydraulic chambers 171.17□ is output from the corresponding output capos 1-LL and 18□, allowing two systems of hydraulic brakes to operate simultaneously and braking the vehicle. .

When the negative pressure booster B is returned to the inoperative state in order to release the brake, each plunger 16. , 16□ is the corresponding return spring 3
The repulsive forces of 01 and 30t return each to the predetermined retraction limit, but if the pressure in each hydraulic chamber 171.17□ decreases during the retraction process, the corresponding one-way seal member 35. , 35□ lips are respectively hydraulic chamber 171.1 due to the pressure difference between front and rear.
7z side, the hydraulic oil in the first oil reservoir 81 passes through the through hole 9°, the front annular oil chamber 111, the radial groove 34+, and the inside of the lip of the front one-way seal member 351, and enters the front hydraulic chamber 1.
71, and the hydraulic oil in the second oil reservoir 8□ is supplied to the through hole 9.
The oil is supplied to the rear hydraulic chamber 17□ through the rear annular oil chamber 11□, the radial groove 34□, the inner side 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, 171, the excess amount is absorbed by each plunger 16+, 1
When 6□ returns to the retreat limit, each relief boat 3L, 3
Oil sump from 8z8. ．． It is emitted to the 8° side.

By the way, the protrusion 28a of the stopper ring 28 attached to the rear plunger 16□ only moves forward in the axial direction 423 of the sleeve 13 when the plunger 16t moves forward; When the plunger 16g retreats, it comes into contact with the stopper wall 29 of the sleeve 13 to restrict the retreat limit of the plunger 1G□. In this way, since the rear plunger 16t is restricted to its backward limit within the cylinder hole 10, the rear plunger 16t
The cylinder body 1 and the bearing 14 can be shortened to expose the rear end of the cylinder g.

C0 Effects of the Invention As described above, according to the present invention, the plunger is slid onto the sleeve fitted into the cylinder hole adjacent to the front of the bearing,
Since a stopper means is provided between the sleeve and the plunger to restrict the retraction limit of the plunger, the cylinder body and bearing can be shortened to expose the rear end of the plunger, which greatly contributes to making them more compact. obtain.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention; FIG. 1 is a vertical side view of the master cylinder, FIG. 2 is a sectional view taken along the line nn of FIG. 1, and FIG. 3 is an exploded perspective view of the main parts. be. M...Master cylinder

Claims (1)

[Claims] The plunger inserted into the cylinder hole of the cylinder body,
In a master cylinder that is slidably supported by a bearing fixed to the rear end of the cylinder body, a plunger is slid into a sleeve fitted into a cylinder hole adjacent to the front of the bearing, and between these sleeve and plunger. A master cylinder characterized in that it is provided with a stopper means for regulating the retraction limit of the plunger.