JPH0550915A - Poppet valve for master cylinder - Google Patents

Abstract

PURPOSE:To improve the durability of the sealing member of a poppet valve by preventing the deformation of the sealing member to the utmost even when hydraulic pressure in a hydraulic chamber acts on the sealing member of the poppet valve in a relief valve to open and close the relief port of a master cylinder. CONSTITUTION:The cap body 40 of a poppet valve 26 is provided with a shallow circular recess 42 opened on its end face, an annular groove 43 opened on the peripheral edge of the recess 42, the first anchor hole 44 reaching from the peripheral face of the cap body 40 to the annular groove 43, and the second anchor hole 45 crossing a core part 4Oa enclosed by the annular groove 43. A sealing member 41 is filled up in the above parts and baked, and an annular sealing protrusive stripe 41a protruding from the end face of the cap body 40 is thereby formed on the sealing member 41.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a master cylinder poppet valve for opening and closing a relief port of a master cylinder used for operating a hydraulic clutch or brake of an automobile, and more particularly to a poppet valve formed at one end of a valve rod. On the umbrella body,
The present invention relates to an improvement of a cap portion formed by joining a seal member that can be seated on a valve seat facing a hydraulic chamber of a master cylinder.

[0002]

2. Description of the Related Art Such a poppet valve is disclosed, for example, in Japanese Utility Model Laid Open No.
It is already known as disclosed in Japanese Patent Publication No. 39167/1993.

[0003]

In the poppet valve disclosed in the above publication, an umbrella portion is formed by mold-bonding an elastic sealing member to the umbrella body connected to the valve rod so as to cover the entire outer peripheral surface thereof. Therefore, every time the pressure of the hydraulic chamber facing this umbrella portion rises, the elastic seal member receives a high hydraulic pressure on its entire outer peripheral surface to generate a large strain, and the durability of the seal member is impaired by this repetition. There are drawbacks.

The present invention has been made in view of the above points, and an object thereof is to provide a master cylinder poppet valve having high durability by avoiding distortion of a seal member due to high hydraulic pressure.

[0005]

In order to achieve the above object, the present invention relates to an umbrella body having an annular groove which is open to an end surface of the umbrella body, and which reaches the annular groove from an outer peripheral surface of the umbrella body. 1
An anchor hole and a second anchor hole that crosses the core portion of the umbrella body surrounded by the annular groove are provided, and the annular groove and the first and second anchor holes are filled and joined with the seal member. Characterize.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1 and FIG. 2, M is an automobile 2
1 shows a tandem master cylinder for a systematic hydraulic brake, the cylinder body 1 of which is attached to the front surface of a booster shell Bs of a negative pressure booster B. This cylinder body 1
A front piston 2f and a rear piston 2r are fitted in series in the cylinder hole 1a of the cylinder, a front hydraulic chamber 3f is provided between the front piston 2f and the front end wall of the cylinder hole 1a, and a rear portion between the pistons 2f and 2r. Each hydraulic chamber 3r is defined.
Then, two brake hydraulic circuits are connected to the output ports 4f and 4r of both the hydraulic chambers 3f and 3r.

The rear piston 2r is in contact with the front end surface of the bearing 5 fitted to the rear end of the cylinder hole 1a to restrict the backward movement of the piston 2r, and the bearing 24.
Has a piston rod 2b slidably supported on the output rod Bo of the negative pressure booster B.
Are connected.

Each piston 2f, 2r has a cylinder hole 1a.
Are provided with cup seals 5f and 5r that are in close contact with each other, and the intermediate portions of the cup seals have a small diameter so as to define front and rear replenishment oil chambers 6f and 6r in the cylinder hole 1a. Then, oil holes 7f and 7r for communicating these replenishment oil chambers 6f and 6r with the back surfaces of the cup seals 5f and 5r are formed in the pistons 2f and 2r.

A front return spring 8f for urging the front piston 2f in the backward direction is provided in the front hydraulic chamber 3f, and a rear return spring for urging the rear piston 2r in the backward direction is provided between the two pistons 2f and 2r. 8r are compressed respectively.

A cylindrical auxiliary oil tank 9 is integrally connected to the upper part of the cylinder body 1 adjacent to the front supplemental oil chamber 6f.
The main oil tank 10 made of synthetic resin is fitted and connected to the upper end portion.

The inside of the auxiliary oil tank 9 is partitioned into front and rear oil storage chambers 9f and 9r by a partition wall 11 which is integral with the cylinder body 1. The front oil storage chamber 9f has a through hole 12f penetrating its bottom wall.
Via a long hole 13f which communicates with the front replenishment oil chamber 6f through the middle of the front piston 2f and the central portion of the front piston 2f from the long hole 13f. Through a relief port 14f that opens to the valve seat 20 on the front surface thereof and communicates with the front hydraulic chamber 3f. The long hole 13f is provided with a long diameter longer than the sliding stroke of the front piston 2f in the axial direction of the piston 2f.

Relief port 14f of the front piston 2f
A front relief port valve Vf is provided on the front piston 2f to open and close the valve. This relief port valve Vf is
Valve box 15, poppet valve 16, valve spring 17 and valve opening rod 18
It consists of

The valve box 15 has a cup shape having a through hole 19 in its peripheral wall and is fitted to the front end of the front piston 2f.

The poppet valve 16 is composed of an umbrella portion 16a and a valve rod 16b supporting the umbrella portion 16a. The umbrella portion 16a is a valve box so as to face the valve seat 20 in front of the front piston 2f. 15, the valve rod 16b is loosely inserted into the relief port 14f.

The valve spring 17 is housed in the valve casing 15 so as to urge the poppet valve 16 toward the valve seat 20, that is, in the valve closing direction.

The valve opening rod 18 has a long hole 1 in the front piston 2f.
3 is fixed to the cylinder body 1 through the valve rod 3 and opens the poppet valve 16 when the front piston 2f is retracted.
It is designed to receive the rear end of 6b.

On the other hand, the rear oil sump chamber 9r communicates with the rear replenishment oil chamber 6r through a through hole 12r passing through the upper wall of the cylinder body 1. Further, the rear replenishment oil chamber 6r has an intermediate portion of the rear piston 2r. It communicates with the rear hydraulic chamber 3r through a through hole 13r that traverses and a relief port 14r that passes through the central portion of the rear piston 2r and opens to the valve seat 21 on the front surface thereof.

A rear relief port valve Vr is provided on the rear piston 2r for opening and closing the relief port 14r. As shown in FIG. 3, the rear relief port valve Vr includes a valve box 25, a poppet valve 26, a valve spring 27, and a retainer 28 as a valve opening member.

The valve box 25 has a cup shape having a through hole 29 in the peripheral wall and a guide hole 30 in the end wall, and the rear piston 2
It is fitted to the front end of r.

The poppet valve 26 comprises an umbrella portion 26a and a valve rod 26b which supports the umbrella portion, and the valve rod 26b.
An enlarged portion 33 is formed at the tip of the. And the umbrella portion 26a
Is housed in the valve casing 25 so as to face the valve seat 21 on the front surface of the rear piston 2r, and the valve rod 26b is loosely inserted in the guide hole 30.

The valve spring 27 is housed in the valve box 25 so as to urge the poppet valve 26 toward the valve seat 21, that is, in the valve closing direction.

The retainer 28 has a guide hole 34 in the center thereof, and the valve rod 26b is loosely fitted therein and is retained by the enlarged portion 33. The rear return spring 8r is contracted between the retainer 28 and the valve box 25. This rear return spring 8r is given a larger set load than the front return spring 8f.

The retainer 28 is fitted to the rear end portion of the rear piston 2r, and the enlarged portion 33 is slidably fitted into a bag-shaped central hole 35 which is open at the rear end surface of the piston 2r.

The structure of the umbrella portion 26a of the poppet valve 26 will be described with reference to FIGS.

As shown in FIGS. 3 and 4, the umbrella portion 26a.
Is composed of an umbrella body 40 integrated with the valve rod 26b and a seal member 41 joined to the umbrella body 40. A shallow circular recess 42 is formed on the end face of the umbrella body 40, and a deep annular groove 43 that opens along the peripheral edge of the recess 42 is formed. Further, the outer peripheral surface of the umbrella body 40 reaches the annular groove 43. One or more first anchor holes 44 and the core portion 4 of the umbrella body 40 surrounded by the annular groove 43.
One or a plurality of second anchor holes 45 that cross 0a are formed. The first and second anchor holes 44, 45
Are formed all at once by drilling and are arranged on the coaxial line (see FIG. 5). Then, the recess 42, the annular groove 43, and the first and second anchor holes 44, 45 are filled with the rubber seal member 41 and baked. At that time, the seal member 41 is formed with an annular seal protrusion 41 a protruding from the end face of the umbrella body 40.

In molding the seal member 41, as shown in FIG. 6, first, a pair of molds 4 that can be opened and closed.
The umbrella body 40 of the poppet valve 26 is installed in the cavity 48 formed in the facing surfaces of the molds 6, 47, and the molds 46, 47
Of the umbrella body 40 on the runner 49 formed on the facing surface of the
Align the anchor holes 44. Thereafter, the rubber that will serve as the sealing member 41 is injected from the runner 49 into the first anchor hole 44, and the second anchor hole 45, the annular groove 43, and the recess 42
It is spread over and baked.

As shown in FIG. 7, the umbrella portion 16a of the poppet valve 16 in the front relief port valve Vf also has a structure similar to that of the umbrella portion 26a of the poppet valve 26. The same reference numerals are given to the portions corresponding to, and the detailed description of the structure is omitted.

Next, the operation of this embodiment will be described.

When the negative pressure booster B is at rest, the front piston 2f is retained by the elastic force of the front return spring 8f.
8 is held in the retracted limit, and the rear piston 2r
Is held in the retracted limit where it abuts on the bearing 24 by the elastic force of the rear return spring 8r. In this case, since the set load of the return spring 8r is set to be larger than that of the front return spring 8f as described above, the rear return spring 8r causes the front return spring 8f to reach the position where the poppet valve 26 is fully opened. The retainer 34 is pressed forward together with the front piston 2f against the force. The fully open position of the poppet valve 26 is the umbrella portion 26 thereof.
The front end surface 32 of a is regulated by abutting on the peripheral edge of the guide hole 30 of the valve box 25.

On the other hand, in the backward limit of the front piston 2f, the valve opening rod 18 receives the valve rod 16b of the poppet valve 16 and holds the valve 16 in the open position.

When the negative pressure booster B is operated from such a state and the rear rod 2r is moved forward by the output rod Bo, the front piston 2 is first passed through the rear return spring 8r.
The front part return spring 8f is compressed by advancing f.

Thus, according to the forward movement of the front piston 2f, first, in the front relief port valve Vf, the poppet valve 16 separates from the valve opening rod 18 and at the same time, the valve seat 17 is seated by the force of the valve spring 17. Since the relief port 14f is closed, hydraulic pressure is generated in the front hydraulic chamber 3f as the front piston 2f continues to move forward, and the hydraulic pressure is supplied from the output port 4f to the corresponding wheel brake.

When hydraulic pressure is generated in the front hydraulic chamber 3f,
With the forward movement of the rear piston 2r, compression of the rear return spring 8r starts. Then, first, in the rear relief port valve Vr, the poppet valve 26 is released from the retainer 34, and the valve closing action is given by the valve spring 27. Therefore, the seal projection 41a of the seal member 41 is seated on the valve seat 21. The relief port 14r is closed. When the rear relief port valve Vr is thus closed, hydraulic pressure is generated in the rear hydraulic chamber 3r due to the subsequent forward movement of the rear piston 2r, and this hydraulic pressure is supplied from the output port 4r to the corresponding wheel brake. During this time, the enlarged portion 33 of the valve rod 26b slides forward through the center hole 35 of the front piston 2f, so that it does not hinder the forward movement of the rear piston 2f.

By the way, when the pressure in the front and rear hydraulic chambers 3f, 3r is increased, the seal projection 41a of the seal member 41 of each poppet valve 16, 26 has a corresponding valve seat 20 by the hydraulic pressure acting on the front surface of each umbrella portion 16a, 26a. , 21 so that the relief ports 14f, 14r are closed more reliably. The seal member 41 is filled in the recess 42, the annular groove 43, and the first and second anchor holes 44, 45 of the umbrella body 40 and baked, so that the bonding strength with the umbrella body 40 is strong. The first anchor hole 44 that opens to the outer peripheral surface of the umbrella body 40 has a very small cross-sectional area.
Through the anchor hole 44, the seal member 41 is connected to the hydraulic chambers 3f, 3
Since it receives only the hydraulic pressure r, the distortion of the seal member 41 caused by it is extremely small.

Next, if the operation of the negative pressure booster B is released,
Both pistons 2f and 2r are returned to a predetermined retreat limit by the force of respective return springs 8f and 8r, and in the retreating process, hydraulic chambers 3f and 3r are returned.
When r is reduced, the outer peripheral portions of the cup seals 5f and 5r bend forward due to the pressure difference between the front and rear of the cup seals to form a gap between the cup seals 5f and 5r and the inner surface of the cylinder hole 1a.
The hydraulic oil is replenished from the replenishing oil chambers 6f, 6r to the hydraulic chambers 3f, 3r through the oil holes 7f, 7r. If excessive replenishment of the hydraulic oil occurs at that time, when the pistons 2f and 2r return to their retracted limits, the excess amount passes through the relief ports 14f and 14r opened by the poppet valves 16 and 26 and the replenishment oil chambers 6f and 6r. Returned to.

[0037]

As described above, according to the present invention, the umbrella body is provided with an annular groove opening to the umbrella body end surface, a first anchor hole reaching from the umbrella body outer peripheral surface to the annular groove, and Since the second anchor hole that crosses the core portion of the umbrella body surrounded by the annular groove is provided and the annular groove and the first and second anchor holes are filled and joined with the seal member, the annular groove and the first The second anchor hole enhances the coupling strength of the seal member with the main body of the umbrella portion, and can prevent distortion of the seal member due to the hydraulic pressure applied to the outer peripheral surface of the umbrella portion as much as possible, thereby improving the durability of the seal member. You can

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a master cylinder embodying the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is an enlarged vertical cross-sectional side view of essential parts of the poppet valve of the rear relief port valve in FIG.

4 is a sectional view taken along line 4-4 of FIG.

FIG. 5 is an enlarged side view of a longitudinal section of a main part of the poppet valve before baking a seal member.

FIG. 6 is an explanatory view of a method for molding the seal member of the poppet valve.

FIG. 7 is an enlarged side view of a longitudinal section of a main part of the poppet valve of the front relief port valve in FIG.

[Explanation of symbols]

 3f, 3r hydraulic chamber 16 poppet valve 16a umbrella portion 16b valve rod 20,21 valve seat 26 poppet valve 26a umbrella portion 26b valve rod 40 umbrella body 41 seal member 43 annular groove 44, 45 first and second anchor hole M master Cylinder

Claims (1)

[Claims] 1. A valve seat (20, 21) facing a hydraulic chamber (3f, 3r) of a master cylinder (M) is seated on an umbrella body (40) formed at one end of a valve rod (16b, 26b). A seal member (41) that can be joined is joined to the umbrella portion (16a, 26a
In the poppet valve for a master cylinder configured as a), in the umbrella body (40), an annular groove (43) opened to an end surface of the umbrella body, and from the outer peripheral surface of the umbrella body, the annular groove (4) is formed.
3) is provided with a first anchor hole (44) and a second anchor hole (45) that traverses the core portion (40a) of the umbrella body surrounded by the annular groove (43). Four
3) and the first and second anchor holes (44, 45) are filled and joined with the seal member (41), and a poppet valve for a master cylinder is provided.