JP2603049Y2 - Seal for valve stem - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve stem seal mounted on a valve stem of an intake / exhaust mechanism of an engine of an automobile or a general industrial machine.

[0002]

2. Description of the Related Art FIG. 2A is a sectional view of a main part of an intake and exhaust mechanism of an engine. A cylinder head 100 as a housing is provided with a lubricating liquid chamber 101 and a port 102, and a hole 103 penetrating from the lubricating liquid chamber 101 toward the port 102 is provided with a guide 104 as a guide cylinder.

A valve stem 105 is inserted into a guide 104 so as to be reciprocable. On one end side of the valve stem 105, a valve cap 106 for opening and closing the port 102 is provided.
A retainer 107 is attached to the other end, that is, the lubricating liquid chamber 101 side. A spring 108 is interposed between the retainer 107 and the housing 100.

An oil seal 1 as a seal ring is provided on the upper end side of the guide 104, that is, on the lubricating liquid chamber 101 side.
09 is attached. This oil seal 109 is shown in FIG.
As shown in (B), a metal ring 110 and a seal body 111 made of a rubber-like elastic body are provided. The seal body 111 has a seal lip 112.

[0005] Reference numeral 113 denotes a swing arm, and 114 denotes a cam.

In the above configuration, the swing arm 113 swings with the rotation of the cam 114, and the valve stem 105 reciprocates in the guide 104. As a result, the space between the port 102 and the combustion chamber 115 is opened and closed by the valve cap 106, and hot gas is sucked and exhausted.

On the other hand, the seal lip 112 of the oil seal 109 has a predetermined interference with the valve stem 105, and the lubricating oil in the lubricating fluid chamber 101 is removed from the inner peripheral surface of the guide 104 by the seal lip 112. The amount that leaks into the gap A with respect to 105 is controlled.

As described above, the oil seal 109 supplies the gap A with the lubricating oil, and the guide 104 and the valve stem 1
It has both the function of preventing the seizure of the lubrication oil 05 and the function of controlling the supply amount of the lubricating oil.

[0009]

However, in the above-described conventional example, the lubricating oil is transmitted from the gap A to the port 102 through the hole 103 to cause waste of the lubricating oil. Therefore, when the supply amount of the lubricating oil is reduced, wear and seizure occur due to friction.

As a countermeasure against the above-mentioned problem, it is conceivable to use an oil seal having a tightening margin aiming at an intermediate point between "leak" and "stop". Must be designed and machined with high precision, which leads to an increase in manufacturing costs, and is not practical.

The present invention has been made to solve the above problems, and can efficiently lubricate a sliding surface between a guide cylinder and a valve stem without wasting a lubricating liquid, and a valve which does not require high design and processing accuracy. It is intended to provide a stem seal.

[0012]

According to the present invention, a guide cylinder is mounted on a housing having a lubricant chamber so that one end of the guide cylinder faces the lubricant chamber. A valve stem is reciprocally housed in the cylinder, and a cutout provided on the inner peripheral surface at the other end of the guide cylinder.
A seal ring formed integrally with the surface saw-shaped groove to retain a lubricating liquid supplied to a gap between the inner peripheral surface of the guide cylinder and the valve stem in the gap ;
Is shaped by the saw-shaped groove of the cross section during molding.
In the lubricating fluid chamber formed by the difference in the amount of radial restoration
It is characterized by having a cross-section undulation inclined toward
And

[0013]

[Function] Since the seal ring is provided at the other end of the guide cylinder,
The supply of the lubricating liquid supplied from one end of the guide cylinder is not hindered, and the lubricating liquid is smoothly supplied to the gap. The lubricating oil supplied to the gap is held in the gap by the holding portion of the seal ring.

[0014]

FIG. 1A is a sectional view of an essential part of an intake / exhaust mechanism of an engine. A cylinder head 1 as a housing is provided with a lubricating liquid chamber 2 and a port 3, and a hole 4 penetrating from the lubricating liquid chamber 4 to the port 3 is provided with a guide 5 as a guide cylinder. One end, ie, the upper end, of the guide 5 is located in the lubricating liquid chamber 2, and the other end, ie, the lower end, faces the port 3.

A valve stem 6 is reciprocally inserted into the guide 5. At one end of the valve stem 6, a valve cap 7 for opening and closing the port 3 is provided.
A retainer 8 is attached to the lubricating liquid chamber 2 side. A spring 9 is provided between the retainer 8 and the housing 1.
Is interposed.

On the other hand, on the lower end side of the guide 5 and at a position facing the port 3, that is, in the hole 4, a resin seal ring 10 as shown in FIG. That is, the shape of the inner peripheral surface of the hole 4 is corrugated and saw-toothed, the groove 11 is formed, and the outer peripheral surface of the seal ring 10 is provided with an annular projection 17 that engages with the groove 11.

The inner peripheral surface of the seal ring 10
A holding portion, that is, an annular undulation 12 having a corrugated cross-sectional shape toward the upper end of the guide 5 is provided.

After the guide 5 is placed in the mold in advance and the middle mold is inserted into the hole 4, the seal ring 10 is molded integrally by injecting a resin molding material between the middle mold and the guide 5. Things. Since the area in the radial direction is different between the groove 11 and the other parts, the amount of the compressed molding material is also different.

As a result, when the middle mold is pulled out, a difference occurs in the amount of restoration of the molding material in the radial direction, and the undulation 12 is formed. The size of the swell 12 is 0.
It is as small as about 05 mm or less. The seal ring 10 is made of a material having excellent heat resistance such as ethylene tetrafluoride resin.

Further, a swing arm 13, a cam 14, a pusher 15 and the like are provided on the lubricating liquid chamber 2 side.

In the above configuration, the swing arm 13 swings with the rotation of the cam 14, and the valve stem 6 reciprocates in the hole 4 of the guide 5. As a result, the space between the port 3 and the combustion chamber 16 is opened and closed by the valve cap 7, and hot gas is sucked and exhausted.

Since the seal ring 10 is located at the lower end of the guide 5, the operation of supplying the lubricating oil in the lubricating fluid chamber 2 into the hole 4, that is, the gap B between the guide 5 and the valve stem 6, is hindered. Supply smoothly without any.

Therefore, the friction between the guide 5 and the valve stem 6 can be reduced, the wear and seizure thereof can be prevented, and the operating energy loss to the valve stem 6 can be reduced.

On the other hand, the undulation 12 of the seal ring 10 is inclined toward the upper end of the guide 5 and the valve stem 6
With a predetermined interference, only the function of retaining the lubricating oil basically functions as a stop seal,
No lubricating oil leaking function is required.

Therefore, the lubricating oil supplied to the gap B can be held, and the lubricating oil does not leak to the port 3 side, thereby preventing waste.

Further, since it is only necessary to basically exert only the stop sealing function, the design accuracy and processing accuracy required for the inner diameter of the seal ring 10 can be relaxed as compared with the related art, and the manufacturing cost can be suppressed.

Further, since the seal ring 10 is made of a resin having excellent heat resistance, the seal ring 10 has good durability even when the inside of the port 3 is heated to a high temperature, and has a longer life than a seal made of a rubber-like elastic body.

[0028]

As described above, since the seal ring is provided at the other end of the guide cylinder, the supply of the lubricating liquid supplied from one end of the guide cylinder is not obstructed, and the lubricating liquid smoothly flows into the gap. Supplied.

Therefore, the friction between the guide cylinder and the valve stem can be reduced by the efficient lubrication function, and the wear and seizure thereof can be prevented.

On the other hand, since the holding portion of the seal ring holds the lubricating oil supplied to the gap, waste of the lubricating oil can be prevented.

Further, the seal ring only needs to have a function of retaining the lubricating liquid, and does not need to have a function of leaking. Therefore, required design accuracy and processing accuracy can be relaxed as compared with the conventional case.
Manufacturing costs can be reduced.

[Brief description of the drawings]

1A is a sectional view of a valve stem mechanism of an engine to which the present invention is applied, FIG. 1B is an enlarged sectional view of a main part of FIG. 1A,
(C) is an enlarged sectional view of a main part of (B).

2A is a sectional view of a conventional valve stem mechanism of an engine, and FIG. 2B is an enlarged sectional view of a main part of FIG. 2A.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head (housing) 2 Lubricating fluid chamber 3 Port 4 hole 5 Guide (guide cylinder) 6 Valve stem 7 Valve cap 8 Retainer 9 Spring 10 Seal ring 11 Groove 12 Wave (holding part) 13 Swing arm 14 Cam 15 Pushing 16 Combustion chamber 17 Projection B Clearance

Claims (1)

(57) [Scope of request for utility model registration] 1. A guide cylinder is attached to a housing having a lubricant chamber so that one end of the guide cylinder faces the lubricant chamber, and a valve stem is reciprocally housed in the guide cylinder. Cross-section saw provided on the inner peripheral surface at the other end of the cylinder
The lubricating fluid, which is formed integrally with the groove and is supplied to the gap between the inner peripheral surface of the guide cylinder and the valve stem, is retained in the gap.
A seal ring is provided, and the seal ring is formed by the saw-shaped groove of the cross section.
Formed by differences in the amount of radial restoration during molding
Has a wavy cross section that is inclined toward the lubricant chamber side
Sealing valve stem, characterized in that that.