JPH0447370Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Field of Application of the Invention" This invention relates to a valve stem seal device used in an internal combustion engine.

``Prior art and its problems'' Conventional valve stem seals are fitted and fixed onto the valve guide, with the lip part in contact with the outer periphery of the valve stem, and the engine oil is scraped off to form an oil film of a predetermined thickness around the valve stem. It is configured to prevent burning with the valve guide.

However, if the amount of oil film leaked from the valve stem is too large, it will cause oil leakage into the combustion chamber, and if it is too little, there will be a problem of seizure.Therefore, it is necessary to always ensure an appropriate amount of leakage. Tight adjustment of quantities is not always easy.

"Means for solving the problem" This invention aims to solve the above-mentioned conventional problem.
A guide sleeve with a tapered surface on the inner periphery of the tip that reduces in diameter toward the tip is screwed onto the outer periphery of the end of the valve guide so that it can be freely adjusted. A discontinuous annular seal ring having a tapered surface that imitates the tapered surface of the guide sleeve and having a split part is fitted to the valve guide, and the pressing force of a compression spring loaded between the seal ring and the lower end of the valve guide is fitted. By pressing the lip provided on the inner circumference of the seal ring against the outer circumference of the valve stem and sealing it, oil leakage is prevented for a long time, and the amount of oil leakage can be adjusted appropriately by adjusting the threading of the guide sleeve. This paper proposes a valve stem seal device that enables this.

"Embodiment" Below, an embodiment of this invention shown in the drawings will be described.A female thread 4 provided at the base end of the guide sleeve 3 is screwed into a male thread 2 provided at the outer periphery of the lower end or upper end of the valve guide 1. This means that it is screwed in and can be adjusted freely.

The tip of the guide sleeve 3 is provided with a tapered surface 5 whose diameter decreases toward the tip.
An annular seal ring 6 made of synthetic resin, metal, ceramic, or the like is fitted.

The seal ring 6 has an inner diameter approximately the same as that of the valve stem 7, and is formed into a discontinuous annular shape having a diagonal split 8 in part, and a tapered surface 9 that follows the tapered surface 5 of the guide sleeve 3 is provided on the outer periphery of the seal ring 6. A plurality of lips 10 are provided on the inner periphery.

A compression spring 11 is installed between the flat surface of the seal ring 6 and the lower end of the valve guide 1, and the seal ring 6 is constantly pressed in the axial direction by the pressing force of the compression spring 11. The strength can be adjusted by screwing and adjusting the sleeve 3.

Then, due to the elastic force of the compression spring 11, an axial force is applied to the tapered surface 9 on the outer circumference of the seal ring 6 in the direction of the distal end of the guide sleeve 3 along the tapered surface 5 of the guide sleeve 3.
This axial force generates a radial component force by the tapered surface 5, and a force in the direction of contracting the diameter always acts.
As a result, the inner lip 10 is connected to the valve stem 7.
It is configured to be pressed against the outer periphery of the cylinder with a required tension force to form a seal.

"Operation of the invention" In the above configuration, when the guide sleeve 3 is attached to the lower end of the valve guide 1 as shown in FIG. 1, the valve guide 1 and the valve stem 8
Even if the oil that lubricates the valve stem 7 leaks out below the valve guide 1 as an oil film around the valve stem 7,
The lip 10 of the seal ring 6 can scrape off this and reliably prevent it from entering the engine.

In addition, when the guide sleeve 3 is attached to the upper end of the valve guide 1 in the opposite manner to the above, the seal ring 6 functions in the same way as a conventional valve stem seal.
By adjusting the tightening force of the seal ring 6 against the valve stem 7 by screwing in the guide sleeve 3, the amount of oil scraped off on the outer periphery of the valve stem 6 is adjusted, and an oil film with a constant amount of leakage is formed. In addition, even if the lip 10 is worn out with use, the compression spring 11 can be
Due to the elastic force of , it is possible to always seal with a constant tension force and maintain an appropriate amount of oil leakage.

"Effect of the invention" As described above, according to this invention, a guide sleeve having a tapered surface formed on the inner periphery of the distal end with a tapered surface whose diameter decreases toward the distal end is screwed onto the outer periphery of the end of the valve guide and adjusted. A discontinuous annular seal ring having a lip on the inner periphery, a tapered surface imitating the tapered surface of the guide sleeve on the outer periphery, and a split part is fitted into the distal end of the guide sleeve. A compression spring is installed between the seal ring and the lower end of the valve guide, and the pressure of the compression spring presses the lip provided on the inner periphery of the seal ring against the outer periphery of the valve stem, creating a seal. When this device is used at the lower end of the valve guide, oil leakage can be prevented for a long time without requiring adjustment of the amount of leakage.

In addition, when this device is used at the lower end of the valve guide, the amount of oil leak can be adjusted appropriately by screwing the guide sleeve, and even if the lip is worn out due to long-term use, the compression The elastic force of the spring always seals with a constant tension, making it possible to maintain an appropriate amount of oil leakage.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of a main part showing an embodiment of this invention, and FIG. 2 is a longitudinal sectional side view of a seal ring used in this invention. 1...Valve guide, 2...Male thread part, 3...
Guide sleeve, 4...Female threaded portion, 5...Tapered surface, 6...Seal ring, 7...Valve stem, 8...Split, 9...Tapered surface, 10
...Rip, 11...Compression spring.

Claims (1)

[Scope of utility model registration request] A guide sleeve, which has a tapered surface on the inner periphery of the distal end that is formed to reduce the diameter toward the distal end, is screwed onto the outer periphery of the end of the valve guide so as to be freely adjustable. A discontinuous annular seal ring having a lip on the outer periphery and a tapered surface imitating the tapered surface of the guide sleeve and a split portion on the outer periphery is fitted, and the seal ring and the end of the valve guide are fitted. A valve stem sealing device characterized in that a compression spring is installed between the valve stems and a lip provided on the inner periphery of the seal ring is pressed against the outer periphery of the valve stem by the pressing force of the compression spring to seal the valve stem.