JPH0379214B2 - - Google Patents

Description

Detailed Description of the Invention A. Object of the Invention (1) Industrial Field of Application The present invention provides a method for coupling a cylinder body of a master cylinder and a booster shell of a negative pressure booster with a sealing member sandwiched therebetween; The rear end of the piston that can slide in the cylinder hole of the cylinder body is inserted into the booster shell to connect with the output rod of the negative pressure booster, and the lip of the seal member is brought into close contact with the outer peripheral surface of the piston. The present invention relates to a master 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 that restricts the retraction limit of the piston is fitted into the rear end of the cylinder body, and an annular stopper member is fitted to the rear end of the cylinder body to prevent the stopper member from slipping out. Since the rear end is held down by the booster shell, when the cylinder body and booster shell are separated for maintenance, the stopper member may immediately fall off from the cylinder body together with the piston, etc., and there is a risk of damaging them.

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

B. 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 onto 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 retainer 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 retainer screw. It is characterized in that the lip of the sealing member is accommodated in the formed tool engaging recess.

(2) Effect According to the above configuration, even if the cylinder body and 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, so the seal 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 seal member interposed between the cylinder body and the booster shell.
There is no need to provide a special space for the lip between the cylinder body and the booster shell, and the overall length of the assembly can be reduced accordingly.

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

First, in FIGS. 1 to 3 showing the 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 booster 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 ₁ and 8 ₂ by the partition wall 7, and these oil reservoirs 8 ₁ and 8 ₂
are each supplied with hydraulic oil from the main oil reservoir 4.

The first and second oil reservoirs 8 ₁ and 8 ₂ have through holes 9 ₁ and 8 2 , respectively.
It communicates with the cylinder hole 10 of the cylinder body 1 via 9 ₂ . The cylinder 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, a third hole 10c having a larger diameter than the second hole 10b and continuous to the rear end, and a fourth hole 10d which has a larger diameter than the third hole 10c, is continuous to the rear end, and has an open rear end, and a front partition wall collar 12 ₁ is provided at the step between the second hole 10b and the third hole 10c. The sleeve 13 that contacts the rear surface of the collar ₁₂₁ is fitted into the third hole 10c and the fourth hole 10c.
The rear bulkhead collar 12 2 that is fitted over the hole 10 d and abuts the rear end of this sleeve ₁₃ and the bearing 14 that abuts the rear surface of this collar 12 ₂ are connected to the fourth hole 1 .
An annular retaining screw 15 that is fitted into the fourth hole 10d and presses the rear surface of the bearing 14 is screwed into the rear opening of the fourth hole 10d.

A tool engagement recess 40 having a hexagonal cross section is formed in the rear end surface of the cap screw 15, and the cap screw 15 is attached and removed by a tool (not shown) that is engaged with this recess 40.

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 connected to the annular groove 4 on the inner peripheral surface of the fourth hole 10d.
2. A horizontal hole 43 in the cylinder body 1 connected to the lower part of this annular groove 42 and a discharge groove 44 formed between the lower joint surfaces of the cylinder body 1 and the booster shell 2.
It is connected to the outside through. 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 penetrating into the booster shell 2. can.

The sleeve 13 defines, by its outer peripheral surface, a front annular oil chamber 11 ₁ connected to the front through hole 9 ₁ as a third hole 10c, and a rear annular oil chamber 11 ₂ connected to the through hole 9 ₂ as a third hole 10c. It is defined in four holes 10d.

The sleeve 13 has a pair of front and rear pistons 16 ₁ ,
16 ₂ is slid, and the front piston 16 ₁ and the first hole 1
A front hydraulic chamber 17 ₁ is defined between the front end walls of 0a,
A rear hydraulic chamber 17 ₂ is defined between both pistons 16 ₁ and 16 ₂ . These hydraulic chambers 17 ₁ and 17 ₂ are communicated with two brake hydraulic circuits via front and rear output ports 18 ₁ and 18 ₂ of the cylinder body 1, respectively.

The rear end of the rear piston 16 ₂ passes through the rear bulkhead collar 12 ₂ and the bearing 14 to extend to the rear of the cylinder body 1, and further passes through the front wall of the booster shell 2 to connect with the output rod 19 of the negative pressure booster B. do.

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

This sealing member 21 includes a pair of front and rear lips 21a, 21 that are in close contact with the outer peripheral surface of the rear piston ₁₆₂ .
b, and the front lip 21a extends forward from the rear lip 21b and is received in the tool engaging recess 40 of the cap screw 15.

In order to communicate between the rear hydraulic chamber 17 ₂ and the rear output port 18 ₂ , the sleeve 13 is provided with an axial groove 23 running on its inner circumference, a lateral hole 24 , and an annular groove 25 running on its outer circumference.

A stopper ring 28 having one cut 27 is attached to the outer peripheral groove 26 of the rear piston 16 ₂ . This stopper ring 28 includes one or more protrusions 2 that protrude outward from the outer peripheral surface of the rear piston ₁₆₂ .
8a, and this protrusion 28a is engaged with the axial groove 23 of the sleeve 13. Its axial groove 23
The rear end is closed by a stopper wall 29 that is integrated with the sleeve 13, and when the projection 28a comes into contact with this stopper wall 29, the rear piston 1
A predetermined retreat limit of 6 ₂ is regulated. Therefore,
The stopper ring 28 and the stopper wall 29 constitute the stopper means of the present invention.

A bottomed spring holding hole 31 _{2 is provided on the front end surface of the rear piston 16 2 to} receive a rear return spring 30 ₂ that urges the piston 16 ₂ in the backward direction.
In addition, the rear piston 16 ₂ has a spring holding hole 31 _{2 .}
A guide bolt 32 ₂ is screwed onto the guide bolt _{32 2} and projects _a fixed length from the end wall of the shaft in the axial direction. Slidingly connected within the range.

A radial groove 34 ₂ connected to the rear annular oil chamber 11 ₂ is formed in the rear bulkhead collar 12 2 , and a rear one-way seal member 35 ₂ allows oil to flow from this groove 34 ₂ to the axial groove 23 of the sleeve ₁₃ . is attached to the rear end of the sleeve 13 with its lip in close contact with the outer peripheral surface of the rear piston ₁₆₂ .

Also, at the rear end of the sleeve 13 is a retainer 36 ₂ that holds the front end of the rear one-way seal member 35 _{2 .}
and a spacer 37 ₂ inserted between the rear one-way seal member 35 ₂ and the rear bulkhead collar 12 ₂ .

The rear piston 16 ₂ is provided with a rear relief port 38 2 that communicates between the radial groove 34 ₂ and the spring retaining hole 31 immediately after the rear one-way seal member 35 ₂ when the rear piston 16 ₂ is at a predetermined retraction limit. .

Further, a seal member 39 ₂ is attached to the bearing 14 to bring the lip into close contact with the outer peripheral surface of the rear piston 16 ₂ .

On the other hand, the front end of the front piston 16 ₁ extends through the front partition wall collar 12 ₁ to the first hole 10a, and the front end surface thereof has a front portion that urges the front piston 16 ₁ in the backward direction. A bottomed spring holding hole 31 ₁ is provided for receiving the return spring 30 ₁ . Further, a guide bolt 32 ₁ that protrudes in the axial direction by a certain length from the end wall of the spring holding hole 31 ₁ is screwed onto the front piston 16 ₁ , and the front return spring 30 ₁ is attached to the guide bolt 32 ₁ . A hat-shaped spring holding cylinder 33 ₁ supporting the front end is slid together.

A predetermined retraction limit of the front piston 16 ₁ is regulated by the rear end coming into contact with the spring retaining cylinder 33 ₂ in the extended position. In this case, the front return spring 30 ₁ transfers its set load to the rear return spring 30 so as to keep the spring holding cylinder 33 ₂ in a predetermined extended position.
It is set weaker than ₂ .

The front bulkhead collar 12 ₁ has a front annular oil chamber 11 ₁ .
A front one-way seal member 35 ₁ that only allows oil to flow from this groove 34 ₁ to the front hydraulic chamber 17 ₁ connects the lip to the front piston 16 _{1 .} It is attached to the second hole 10b in close contact with the outer peripheral surface of.

A retainer 36 ₁ that holds the front end of the front one-way seal member 35 ₁ and a spacer 37 ₁ that is inserted between the seal member 35 1 _and the front partition collar 12 ₁ are attached to the second hole 10b. be done.

The front piston 16 ₁ has a radial groove 34 ₁ and a spring retaining hole 31 ₁ when it is at a predetermined retraction limit.
A front relief port 38 ₁ communicating therebetween is bored.

Further, a sealing member 39 ₁ is attached to the front end of the sleeve 13 to bring the lip into close contact with the outer peripheral surface of the piston 16 ₁ .

Here, when the front and rear pistons 16 ₁ and 16 ₂ each occupy a predetermined retreat position, the forward protrusion length of the front piston 16 ₁ from the front one-way seal member 35 ₁ is l ₁ , and both pistons 16 ₁ , 16 ₂ interval l ₂
Then, l ₁ > l ₂ is set. In this way, even if the front piston 16 ₁ abnormally retreats until it comes into contact with the front end of the rear piston 16 ₂ due to damage to the rear return spring 30 ₂ , the front piston 16 1 will move from the front one-way seal member 35 ₁ to the front piston 16 ₁ . can be prevented from slipping out backwards.

Next, the operation of this embodiment will be explained.

Now, operate negative pressure booster B and increase its output rod 1.
9 is pushed forward, both pistons 16 ₁ , 16 ₂ are pressed by the corresponding return springs 30 ₁ , 16 2 , respectively.
Move forward while compressing 30 ₂ . Then, when the relief port 38 ₁ of the front piston 16 ₁ moves to the front of the front one-way seal member 35 ₁ , hydraulic pressure is generated in the front hydraulic chamber 17 ₁ according to the forward force of the front piston 16 ₁ . Further, when the relief port 38 ₂ of the rear piston 16 ₂ moves to the front of the rear one-way seal member 35 ₂ , hydraulic pressure is generated in the rear hydraulic chamber 17 ₂ according to the forward force of the rear piston 16 ₂ .

The hydraulic pressure generated in the front and rear hydraulic chambers 17 ₁ , 17 ₂ is transferred to the corresponding output ports 18 ₁ , 18 _{2 .}
It is possible to simultaneously operate two hydraulic brake systems and apply braking to a car.

When the negative pressure booster B is returned to the inoperative state in order to release the brake, each piston 16 ₁ , 16 ₂ is returned to a predetermined retraction limit by the repulsive force of the corresponding return spring 30 ₁ , 30 ₂ , but after that, If the pressure in each hydraulic chamber 17 ₁ , 17 ₂ is reduced during the retraction process, the lips of the corresponding one-way seal members 35 ₁ , 35 ₂ will bend toward the hydraulic chambers 17 ₁ , 17 ₂ due to the pressure difference between the front and rear, respectively.
Hydraulic oil in the first oil reservoir 8 ₁ is supplied to the front hydraulic chamber 17 ₁ through the through hole 9 ₁ , the front annular oil chamber 11 ₁ , the radial groove 34 ₁ and the inside of the lip of the front one-way seal member 35 ₁ . In addition, the hydraulic oil in the second oil reservoir ₈₂ flows through the through hole 9.
₂ , the rear hydraulic chamber 17 2 is supplied through the rear annular oil chamber 11 ₂ , the radial groove 34 ₂ , the inner side of the lip of the rear one-way seal member 35 ₂ , and the axial groove ₂₃ .

At this time, if excess hydraulic oil is supplied to each hydraulic chamber 17 ₁ , 17 ₂ , the excess amount will be absorbed by each relief port 38 ₁ , 38 ₂ when each piston 16 ₁ , 16 ₂ returns to the retracting limit. The oil is discharged from the oil sump 8 ₁ and 8 ₂ side.

By the way, the projection 28a of the stopper ring 28 attached to the rear piston _{16 2}
When the piston 162 moves forward, it only moves the axial groove 23 of the sleeve 13 forward, and does not impede the forward movement of the piston ₁₆₂ , and when the piston ₁₆₂ moves backward,
The piston 162 comes into contact with the stopper wall 29 of the sleeve 13 to restrict the backward limit of the piston ₁₆₂ . In this way, the retraction limit of the rear piston ₁₆₂ is regulated by the cylinder hole 1.
0, so remove the cylinder body 1 and bearing 1 so as to expose the rear end of the rear piston 16 ₂ .
4 can be shortened.

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 shortened.

Furthermore, even if the cylinder body 1 and booster shell 2 are separated for maintenance, for example, the sleeve 13 and the front and rear pistons 16 ₁ and 16 ₂ cannot be taken out from the cylinder hole 10 unless the retaining screw 15 is removed. Therefore, it is possible to prevent them from falling off.

Furthermore, even when the cap screw 15 is rotated for attachment/detachment, the rotational force is not transmitted to the rear piston 16 ₂ , so the sealing member around the rear piston 16 ₂ is not twisted or damaged.

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 ₁₂₂ are integrated. are given the same symbols.

C. Effects of the Invention As described above, according to the present invention, the retraction limit of the piston is restricted between the sleeve fitted into the cylinder hole of the cylinder body and the piston that slides on the inner peripheral surface of the sleeve. A stopper means is provided, an annular retaining screw surrounding the piston is screwed into the rear opening of the cylinder hole to fix the sleeve, and a lip of the sealing member is inserted into a tool engagement recess formed at the rear end of the retaining screw. Since the cylinder body and booster shell are housed in the housing, even if the cylinder body and booster shell are separated, the retaining screw can prevent the sleeve, piston, etc. from falling off from the cylinder body, and when the retaining screw is attached or removed, no rotational force is applied to the piston. It is possible to prevent the seal member around the piston from being twisted or damaged, and furthermore, since the tool engagement recess of the presser foot serves as a recess for accommodating the lip of the seal member,
The overall length of the assembly can be shortened, contributing to its compactness.

[Brief explanation of drawings]

1 to 3 show a first embodiment of the present invention, in which FIG. 1 is a vertical sectional side view of an assembly of a master cylinder and a negative pressure booster, and FIG. 2 is a sectional view taken along the line -- in FIG. 1. , 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, 1...
Cylinder body, 2... Booster shell, 10... Cylinder hole, 13... Sleeve, 15... Holding screw, 16
₂ ... Piston, 21... Seal member, 21a... Lip, 28, 29... Stopper ring and stopper wall constituting stopper means, 40... Tool engaging recess.

Claims (1)

[Claims] 1. Connect the cylinder body of the master cylinder and the booster shell of the negative pressure booster with a seal member sandwiched between them, and connect the rear end of the piston that can slide in the cylinder hole of the cylinder body to the output rod of the negative pressure booster. Rush into the booster shell to connect to the
In an assembly of a master cylinder and a negative pressure booster, in which the lip of the sealing member is brought into close contact with the outer peripheral surface of the piston, a sleeve is fitted into the cylinder hole of the cylinder body, and the lip is slidably fitted onto the inner peripheral surface of the sleeve. A stopper means for regulating the retraction limit of the piston is provided between the piston and the piston, and an annular retainer screw surrounding the piston is screwed to fix the sleeve to the rear opening of the cylinder hole, and the rear end of the retainer screw is screwed into the rear opening of the cylinder hole. 1. An assembly of a master cylinder and a negative pressure booster, characterized in that a lip of a sealing member is housed in a tool engaging recess formed in the cylinder.