JPH0721844Y2 - Valve stem seal - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve stem seal which is mounted on a valve guide arranged at an intake and exhaust portion of an internal combustion engine to seal a valve stem, and more specifically, regulates and supplies an oil amount between its sliding portions. To obtain a valve stem seal.

[0002]

2. Description of the Related Art Conventionally, a valve stem seal for sealing a valve portion of an engine, for example, a stem sliding portion of an intake valve or an exhaust valve, has been mounted in order to reduce oil consumption and discharge clean exhaust gas. At present, efforts are being made to reduce the maximum consumption from 0.5 ml / 10 hr to about 0.1 ml / 10 hr. The flow rate of oil through this seal part can easily clear the above value depending on the design, but when the consumption amount becomes 0.03 ml / 10 hr or less, a friction noise starts to be generated, which is contrary to the above purpose to some extent. It has been found that means must be provided to allow the oil of the above to be supplied to the sliding portion.

A detailed description will be given below with reference to the drawings. As the supply means, there is a structure in which a slit is provided in an auxiliary lip installed in addition to the main lip, as shown in Japanese Utility Model Laid-Open No. 63-164664, or in Japanese Utility Model Laid-Open No. 63-11060 shown in FIG.
A structure in which a step portion (6) is provided on the inner peripheral surface of the lip (4), which is in contact with the reciprocating direction in an oblique spiral shape, has been proposed and implemented as disclosed in Japanese Patent Laid-Open No.

[0004]

However, since all such valve stem seals are provided directly on the contact surface of the lip (4) to operate, the oil supply amount varies depending on the wear deformation of the lip (4). It had a drawback that it changed greatly and could not be controlled delicately, and of course, its durability was extremely low. The present invention has been made in view of such drawbacks, and an object thereof is to provide a valve stem seal capable of constantly supplying optimum oil to a sliding portion.

[0005]

The present invention, as shown in FIG. 1, is a cylindrical body (2) fitted and fixed to a valve guide (1).
And a lip (4) made of an elastic body that is integrally formed on the upper part of the tubular body (2) and is in sliding contact with the valve stem (3), and the valve stem of the lip (4) ( It is characterized in that a plurality of protrusions (5) protruding in a substantially V shape are provided on the inner peripheral surface which is in sliding contact with (3) from the sliding surface upward.

[0006]

The present invention has the following advantages due to the above structure. That is, as shown in FIG. 2, the tip of the lip (4) mounted on the valve guide (1) elastically and circumferentially slidably contacts the valve stem (3), and is further provided above the sliding surface. The substantially V-shaped base portion of the protrusion (5) is in contact with the V-shaped portion as shown in FIG. 3, and the V-shaped portion forms a saucer shape. When the valve stem (3) reciprocates from this situation, the oil in the vicinity of the sliding portion is gathered in one place by the V-shaped portion of the projection (5), and a wedge effect is generated to cause the V-shaped valley portion. A certain amount of oil flows down through the sliding surface. The oil that has flowed down is guided to the sliding surface of the valve guide (1) by the reciprocating motion of the valve stem (3) to provide smooth lubrication.

[0007]

Embodiments In implementing the present invention, the oil supply amount can be adjusted by increasing or decreasing the number of the protrusions (5) provided, but the protrusion height of the protrusions (5) or the V-shaped opening It can be set in any way by adjusting the degree (see FIG. 5) or the position on the sliding surface.

[0008]

With the above structure, the following excellent effects can be obtained. The protrusions (5) make it possible to constantly supply a constant amount of oil to the sliding portion of the valve guide (1), and since it is displaced from the strong pressure contact surface and makes an auxiliary sliding contact, wear resistance is improved. Exhibits excellent and good durability. In addition, the oil supply amount can be adjusted freely, and a valve stem seal most suitable for the required situation can be provided. By supplying the appropriate amount of oil, it is possible to remove deposits (scraps of the leaked oil that are burned and accumulated) that are about to be deposited on the valve umbrella portion.

[0009]

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a valve stem seal of the present invention.

[Fig. 2]

FIG. 1 is an enlarged sectional view of FIG.

FIG. 3 is a perspective view showing a contact surface where a lip is in sliding contact with a valve stem.

FIG. 4 is a cross-sectional view showing a conventional structure without using the present invention.

FIG. 5 is a diagram showing a change in the amount of oil leakage due to the protrusion of the present invention.

[0010]

[Explanation of symbols]

 1 Valve guide 2 Cylindrical body 3 Valve stem 4 Lip 5 Protrusion

Claims (1)

[Scope of utility model registration request] 1. A tubular body (2) fitted and fixed to a valve guide (1), and an elastic lip formed integrally with an upper portion of the tubular body (2) and slidingly contacting a valve stem (3). A valve stem seal comprising (4); said lip (4)
The valve stem seal is characterized in that a plurality of protrusions (5) having a substantially V shape and protruding are provided on the inner peripheral surface of the valve stem (3) in sliding contact with the valve stem (3) upward from the sliding surface.