JPH0417412Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Purpose of the invention (1) Industrial application field The present invention relates to a master cylinder valve device used to operate hydraulic clutches and brakes of automobiles, and in particular, the invention relates to a master cylinder valve device used for operating hydraulic clutches and brakes of automobiles. a valve seat formed in the bore surrounding an inlet port opening into an end face of a hydraulic chamber defined by the piston; and a valve seat so as to separate from the valve seat at the retraction limit of the piston and to seat on the valve seat when the piston moves forward; This invention relates to an improvement in a valve that is slidably connected to a piston.

(2) Prior Art Conventionally, in this type of master cylinder valve device, a valve stem is slidably connected to a piston, and an annular protrusion or groove formed on the outer periphery of the tip of this valve stem has a resilient structure. and an elastic sealing member fitted into the valve (for example, see Japanese Utility Model Publication No. 55-30766).

(3) Problems that the invention aims to solve In general, in a master cylinder equipped with this type of valve device, if excessive hydraulic oil is supplied to the hydraulic chamber by applying a sudden pumping action to the piston, the piston will not function properly. Even if it returns to the retracted position,
A relatively large residual pressure is generated in the hydraulic chamber, and this residual pressure tends to deform the sealing member of the valve and prevent it from separating from the valve seat.

In particular, the valve sealing member in conventional valve devices is simply fitted into the annular protrusion or groove of the valve stem, which causes large deformation due to residual pressure in the hydraulic chamber, causing the valve stem to move more than the amount of deformation. Otherwise, the seal member cannot be separated from the valve seat. Setting the stroke of the valve stem to be large in this way increases the invalid stroke of the piston until the valve sealing member seats on the valve seat when the piston moves forward from the retracted position, which is preferable in terms of operational feeling. do not have.

Therefore, in order to prevent the seal member from coming into close contact with the valve seat due to the residual pressure in the hydraulic chamber, the method disclosed in the above-mentioned publication prevents the seal member from deforming due to the residual pressure and part of it separating from the valve stem. A bypass is provided in the valve stem to communicate between the hydraulic chamber and the inlet port, but in such a case,
If the seal member fails to close the bypass when the piston moves forward, the hydraulic pressure in the hydraulic chamber will leak from the bypass to the inlet port, resulting in an inconvenience.

The present invention was developed in view of the above circumstances, and is a simple and effective method that can accurately respond to the retreat of the piston and separate it from the valve seat without significantly deforming the sealing member even if the residual pressure in the hydraulic chamber is present. The purpose is to provide a master cylinder valve device.

B. Structure of the invention (1) Means for solving the problems According to the invention, in order to achieve the above purpose,
A valve seat is formed surrounding an inlet port that opens to the end face of a hydraulic chamber defined by a piston in the cylinder hole of the cylinder body, and the valve seat is separated from the valve seat at the retraction limit of the piston and is attached to the valve seat when the piston moves forward. It consists of a valve that is slidably connected to the piston so that the valve is seated, and the valve stem is slidably connected to the piston, and the outer peripheral surface of the seal mounting part that is integrally connected to the tip of the stem. In the master cylinder valve device, the seal mounting portion includes a base portion adjacent to the tip of the valve stem, and an intermediate wall attached to the base portion. An anchor hole is formed in the intermediate wall to bury a part of the sealing member across the intermediate wall, and the seal mounting part and the sealing member are completely opposite each other. The surfaces are integrally bonded to each other by vulcanization.

(2) Effect According to the above configuration, the integral bonding effect of the vulcanization adhesion between all opposing surfaces of the seal mounting portion and the seal member is exerted on the outer circumferential surfaces of the base, intermediate wall, and tip of the seal mounting portion. Of course, it is also effective on the inner surface of the anchor hole that crosses the intermediate wall, so
Due to the special provision of the anchor hole, the total opposing area (i.e., the total vulcanized adhesive area) between the seal mounting part and the seal member can be expanded without making the seal mounting part itself particularly large, and the anchor hole is Coupled with the so-called anchor effect obtained by the close mechanical engagement of a part of the seal member, the bonding strength between the seal mounting portion and the seal member is greatly increased,
The support rigidity of the seal member by the valve stem can be extremely effectively increased. As a result, large deformation and rattling of the sealing member due to residual pressure in the hydraulic chamber can be effectively prevented, and the valve can be opened and closed even with slight back and forth movement of the piston. The seal member can be quickly and reliably separated from the valve seat by the valve opening force applied to the stem.

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

First, we will begin with a first embodiment in which the present invention is applied to a clutch master cylinder of an automobile. In FIG. 1, the clutch master cylinder Mc is a cylinder body 1 having a cylinder hole 1a with an open rear end.
and the cylinder body 1 is slid into the cylinder hole 1a.
A piston 2 defining a hydraulic chamber 3 between the front end wall of the piston 2 and the front end wall of the piston 2 .
, a return spring 4 that urges the piston 2 in its backward direction, and a valve device 6 that opens and closes an inlet port 5 that opens at the front end surface of the hydraulic chamber 3 in response to the back and forth movement of the piston 2. , cylinder body 1
An outlet port 7 that opens to the front of the hydraulic chamber 3 is bored in the upper wall of the hydraulic chamber 3 .

The inlet port 5 has an oil guide pipe 8 connected to the oil tank R.
Further, hydraulic conduits 9 connected to hydraulic clutches C are connected to the outlet ports 7, respectively. Further, a clutch pedal (not shown) for operating the piston 2 is connected to the rear end of the piston 2.

The valve device 6 includes a flat valve seat 10 formed on the front end surface of the hydraulic chamber 3 surrounding the opening of the inlet port 5, and a valve 11 that cooperates with the flat valve seat 10. This valve 11 is equipped with a metal valve stem 12 extending along the axis of the cylinder hole 1a, and has an enlarged portion 12a formed at its rear end as a guide hole bored in the piston 2 and opened at its front end surface. It is slid into the hole 13. A hat-shaped retainer 14 is fitted and locked onto the front end of the piston 2 to prevent the enlarged portion 12a from coming out of the guide hole 13.

Further, at the front end of the valve stem 12, a flange-shaped base 15 adjacent to the tip of the valve stem 12 is provided.
and a shaft-shaped tip 16 connected to the front end of the base 15 via a small-diameter intermediate wall 17 are integrally connected to each other. A vertical hole 18 is bored through them and opens at the front end surface of the tip 16,
Furthermore, a plurality of horizontal holes 19 are bored in the intermediate wall 17 as anchor holes that extend radially from the vertical hole 18 and open to the outer peripheral surface of the intermediate wall 17.

An elastic seal member 20 that can be seated on the valve seat 10 is vulcanized and bonded to this seal attachment portion 12b.

When vulcanizing and adhering the seal member ₂₀ , as shown in _{FIG .} Rubber that will become the sealing member 20 is injected into the vertical hole 18 from the gate G, and then inserted into the horizontal hole 19.
It is passed through so as to cover the outer peripheral surfaces of the intermediate wall 17, the base 15, and the tip 16 and protrude slightly forward from the tip 16, and then baked.

Referring again to FIG. 1, the seal mounting portion 12b to which the seal member 20 is attached is accommodated in the valve cage 21 whose open end is brought into contact with the front end surface of the hydraulic chamber 3.
Furthermore, a valve spring 22 is compressed in the valve cage 21 and urges the valve 11 in the closing direction, that is, toward the valve seat 10.

The valve cage 21 is fixed by the return spring 4 at a position where it contacts the front end surface of the hydraulic chamber 3 .

To explain the operation of this first embodiment, when the clutch pedal (not shown) is inactive, the piston 2
is held in the illustrated retracted position by a return spring 4;
The valve stem 12 is then pulled rearward to separate the seal member 20 from the valve seat 10. That is, the valve 11 is kept open. Therefore, since the hydraulic chamber 3 and the inlet port 5 communicate with each other, the hydraulic clutch C releases its working hydraulic chamber to the oil tank R via the hydraulic chamber 3 and the inlet port 5.
It is connected.

Now, in order to shut off the hydraulic clutch C, the piston 2 is returned to the spring 4 by depressing the clutch pedal.
When the valve 11 is moved forward against the force, the valve 11 is initially moved against the sealing member 2 by the force of the valve spring 22.
0 on the valve seat 10, and the inlet port 5
Since the piston 2 moves forward thereafter, hydraulic pressure is generated in the hydraulic chamber 3, and this hydraulic pressure is outputted from the outlet port 7 to the hydraulic clutch C, so that the hydraulic clutch C can be placed in a disconnected state.

By the way, by applying a sudden pumping action to the piston 2, the hydraulic chamber 3 is pumped from the inlet port 5.
When the piston 2 is returned to the normal retracted position after oversupply of hydraulic fluid to 3 receives a pressing force toward the inlet port 5 side due to the residual pressure, and the valve stem 12 tends to deform due to the residual pressure, but the seal mounting portion 12b of the valve stem 12 and all opposing surfaces of the seal member 20 are integrated with each other by vulcanization adhesion. Since the support rigidity of the seal member 20 by the seal mounting portion 12b is extremely high, after the seal member 20 is slightly deformed, it immediately follows the valve stem 12 and is separated from the valve seat 10, and the inlet port 5 can be opened.

FIG. 3 shows a second embodiment in which the present invention is applied to a brake master cylinder.

The brake master cylinder Mb has a cylinder body 31 having a cylinder hole 31a with an open rear end.
, a piston 32 that is slidably engaged with the cylinder hole 31a and defines a hydraulic chamber 33 between the front end wall of the cylinder body 31, and a return spring 34 that urges the piston 32 in the backward direction, and a brake (not shown). The piston 2 is designed to move forward when the pedal is depressed. Exit port 37 of hydraulic chamber 33
is connected to the hydraulic brake B via a hydraulic conduit 39.

The piston 32 is provided with a cup seal 44 at its front end that abuts the cylinder hole 31a, and its intermediate portion has a small diameter so as to define a replenishment oil chamber 45 within the cylinder hole 31a. An oil hole 46 is bored in the piston 32 to communicate the replenishment oil chamber 45 with the back of the cup seal 44.

An oil tank R is connected to the upper part of the cylinder body 31, and this oil tank R is connected to a supply oil chamber 45 through a through hole 38.
communicate with.

Furthermore, the replenishment oil chamber 45 is connected to the oil pressure chamber through an elongated hole 47 that passes through the middle portion of the piston 32 in the lateral direction, and an inlet port 35 that opens from the elongated hole 47 to the front surface of the piston 32 through the center thereof. Connects with 33.

The elongated hole 47 is formed with a long diameter longer than the sliding stroke of the piston 32 in the axial direction of the piston 32. A stopper bolt 48 is loosely fitted into the elongated hole 47 to limit the retraction limit of the piston 32 by coming into contact with the end wall thereof. This stopper bolt 48 is screwed onto the cylinder body 31 (see FIG. 4).

The piston 32 is provided with a valve device 36 for opening and closing the inlet port 35 according to its forward and backward movement. This valve device 36 includes a valve cage 5
1. It is composed of a valve 41 and a valve spring 52.

The valve cage 51 has a bottom wall connected to the valve seat 40.
The valve seat 40 has a cup shape, and is fitted into the front end of the piston 32 with the center hole of the valve seat 40 aligned with the inlet port 35.

The valve 41 has a metal valve stem 42 that is loosely fitted into the inlet port 35, and the front end of the valve stem 42 facing the valve cage 51 has a shaft integrally having a relatively small diameter flange 55a at the rear end. A seal attachment portion 42b is formed, which is composed of a shaped base portion 55 and a short cylindrical tip portion 53 connected to the outer periphery of the front end of the base portion 55 via a disk-shaped intermediate wall 59. The peripheral surface 56 is open at its front end, and the open surface and the outer peripheral side of the base 55 are as follows.
A plurality of through holes 57 as anchor holes are formed in the intermediate wall 59 at intervals in the circumferential direction thereof in a direction along the valve stem axis.

An elastic seal member 50 that can be seated on the valve seat 40 is vulcanized and bonded to this seal attachment portion 42b.

When vulcanizing and adhering the sealing member ₅₀ , as shown in _FIG .
Rubber that will become the sealing member 50 is injected from the gate G of D ₁ into the inner space of the tip 53 , passes through the through hole 57 , covers the outer circumferential surfaces of the tip 53 and the base 55 , and extends slightly from the flange 55 . It is spread so that it protrudes rearward, and then it is baked.

Referring again to FIG. 3, the mounting portion 42b to which the seal member 50 is attached is housed in the valve cage 51, and is moved in the valve closing direction by the valve spring 52.
That is, it is urged toward the valve seat 40.

To explain the operation of the second embodiment, when the piston 32 is received by the stopper bolt 48 and held in the retracted position, the stopper bolt 48 pushes the valve stem 42 forward against the force of the valve spring 52. Thus, the seal member 50 is separated from the valve seat 40. That is, valve 41
is in an open state. Therefore, the hydraulic chamber 33
Since the hydraulic brake B and the inlet port 35 communicate with each other, the hydraulic brake B releases its working hydraulic chamber to the oil tank R via the hydraulic chamber 33 and the inlet port 35, and is in an inactive state.

Now, in order to operate the hydraulic brake B, if the piston 32 is moved forward against the force of the return spring 34 by depressing the brake pedal, the sealing member 50 of the valve 41 will be brought into contact with the valve seat 40 by the first slight advance. Since the piston 32 is seated, that is, the valve 41 is closed, the hydraulic chamber 3 is opened by the subsequent advancement of the piston 32.
Oil pressure is generated at 3, and the oil pressure is output from the outlet port 37 to the hydraulic brake B to operate it.

During this time, the stopper bolt 48 moves relatively within the elongated hole 47 and does not prevent the piston 32 from moving forward.

Also in this brake master cylinder Mb,
When a sudden pumping action is applied to the piston 32, the supply oil chamber 45, the oil hole 46, and the cup seal 4
When the piston 32 is returned to the normal retracted position, the sealing member 50 of the valve 41 is pushed forward from the stopper bolt 48 via the valve stem 42. At the same time, the valve 41 receives a pressing force toward the inlet port 35 due to the residual pressure in the hydraulic chamber 33, which causes the valve 41 to deform. are integrally connected to each other by vulcanization adhesive, and the seal member 50 is formed by the seal mounting portion 42b.
Because the supporting rigidity of the seal member 50 is extremely high, after the seal member 50 is slightly deformed, it is immediately pulled away from the valve seat 40 by the valve opening force from the valve stem 42, and the inlet port 35 can be opened.

C. Effects of the invention As described above, according to the invention, the seal mounting portion, which is integrally connected to the tip of the valve stem and in which the seal member is fitted on the outer peripheral surface, is connected to the base adjacent to the tip of the valve stem, and to the base portion adjacent to the tip of the valve stem. and a tip portion integrally connected to the seal member through an intermediate wall, and an anchor hole is bored in the intermediate wall to bury a part of the seal member across the wall, and the seal mounting portion and the seal Since all opposing surfaces of the members are integrally bonded to each other by vulcanization bonding, the integral bonding effect of the vulcanization bonding between all opposing surfaces of the seal mounting portion and the sealing member is applied to the base and middle portions of the seal mounting portion. It is effective not only on the outer peripheral surfaces of the wall and tip, but also on the inner surface of the anchor hole that crosses the intermediate wall. The effect of being able to expand the total opposing area (i.e., the total vulcanized adhesive area) between the anchor holes without making the seal attachment part itself particularly large, and the fact that a part of the seal member is mechanically closely engaged with the anchor hole. Combined with the so-called anchor effect obtained by It is possible to effectively prevent large deformation and rattling of the sealing member due to residual pressure in the chamber, and the valve can be opened and closed even with a slight movement of the piston back and forth.As a result, the invalid stroke of the piston is reduced. This can contribute to improving the operating feeling of the master cylinder. Furthermore, the structure of the valve stem and seal member is not particularly complicated compared to the conventional one, which is advantageous in terms of cost reduction.

[Brief explanation of the drawing]

Figures 1 and 2 show a first embodiment of the present invention, with Figure 1 being a longitudinal cross-sectional side view of the main parts of a clutch master cylinder, and Figure 2 showing vulcanization of a valve sealing member in the master cylinder. 3 to 5 show the second embodiment of the present invention, and FIG. 3 is a longitudinal cross-sectional side view of the main parts of the brake master cylinder, and FIG. 4 is taken along the - line in FIG. 3. cross section,
FIG. 5 is an explanatory diagram of the procedure for vulcanization and adhesion of the valve sealing member in the same master cylinder. Mb...Brake master cylinder, Mc...Clutch master cylinder, 1...Cylinder body, 1
a... Cylinder hole, 2... Piston, 3... Hydraulic chamber, 5... Inlet port, 6... Valve device, 7...
...Outlet port, 10...Valve seat, 11...
Valve, 12... Valve stem, 15... Base,
16...Tip, 17...Intermediate wall, 19...Horizontal hole as an anchor hole, 20...Elastic sealing member, 22
... Valve spring, 31 ... Cylinder body,
31a...Cylinder hole, 32...Piston, 33
... Hydraulic chamber, 35 ... Inlet port, 36 ... Valve device, 37 ... Outlet port, 40 ... Valve seat, 41 ... Valve, 42 ... Valve stem,
42b...Seal attachment part, 50...Elastic seal member, 52...Valve spring, 53...Tip part,
55...Base, 57...Through hole as anchor hole,
59...Intermediate wall.

Claims (1)

[Scope of utility model registration request] Cylinder holes 1a, 31 of cylinder bodies 1, 31
Valve seats 10, 40 are formed surrounding the inlet ports 5, 35 that open at the end faces of the hydraulic chambers 3, 33 defined by the pistons 2, 32, and the valve seats 10, 40 are formed around the inlet ports 5, 35 at the retraction limit of the pistons 2, 32. 1
0,40 and is slidably connected to the piston 2,32 so as to seat its valve seat 10,40 upon advancement of the piston 2,32.
1, 41, and the valve 11, 41 is
The valve stems 12 and 42 are slidably connected to the pistons 2 and 32, and the seal fittings 12b and 42b are fitted on the outer peripheral surfaces of the seal mounting portions 12b and 42b, which are integrally connected to the tips of the stems, and are seated on the valve seats 10 and 40. In the master cylinder valve device comprising elastic seal members 20, 50, the seal mounting portions 12b, 42b are attached to the valve stems 12, 4.
2, and tip portions 16, 53 integrally connected to the base portions 15, 55 via intermediate walls 17, 59.
7, 59, the sealing member 2 is inserted across the wall.
Anchor hole 19, 57 where part of 0,50 is buried
is formed, and all opposing surfaces of the seal mounting portions 12b, 42b and the seal members 20, 50 are integrally bonded to each other by vulcanization adhesive.
Master cylinder valve device.