JPH0439366Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a valve stem seal used in a valve part of an internal combustion engine, and more specifically, to an improvement of a metal cylinder having a flange part that fits into a valve guide. be.

Conventional valve stem oil seals are used in the valve stem portion of internal combustion engines, and as shown in Figure 1, are devices for adjusting the flow rate of lubricating oil required by the sliding part between the valve stem 7 and the valve guide 5. Then, an elastic body B having a seal lip 1 that contacts the valve stem 7 above the upper end of the metal cylinder A to be fitted into the valve guide 5 is bonded to the metal cylinder A. It had an integrated structure. The cross-sectional shape of the metal cylindrical body A used in this valve stem seal generally has a linear shape below the upper inward flange portion 3, as shown in FIG. A press fitting jig is pressed against the shoulder of the inward flange portion 3 to insert the metal cylinder A into the valve guide 5. However, since the elastic body B that forms the seal lip 1 is integrally connected to the shoulder part on the inside, the contact area of the press-fitting jig is extremely small, making the press-fitting force and direction unstable, and furthermore, the valve stem When the seal needs to be replaced, only the lower end 4 of the metal cylinder A, that is, the thickness part of the metal cylinder A has a place to hook the removal jig. Therefore, it was very difficult to remove the valve guide, and there were many unacceptable disadvantages such as damaging the valve guide 5 or making it impossible to remove the valve guide.

In order to compensate for this drawback, the Jikko Sho 56 shown in Figure 2
A valve stem seal, as disclosed in Japanese Patent No. 20485, has been developed in which the upper part of a metal cylindrical body A is expanded outward to provide a projecting portion 2. With this structure, when pulling out the valve stem seal, when a removal jig is placed on the lower surface of the overhang 2 and pulled upward, the metal cylinder A located below follows the upper overhang 2, allowing for good removal. However, as shown in FIG.
Even if a uniform and accurate vertical pressure is applied to the fitting part located below the uppermost end of the valve guide 5, the fitting part will be inserted at an angle due to the slight difference in contact resistance between the contact peripheral surface between the metal cylinder A and the valve guide 5. There are many risks that the seal may not be installed correctly, such as being damaged or deformed, and the sealing performance and installation workability cannot be improved. Further, since the bending of the overhanging portion 2 is complicated and difficult, there is a drawback that the cost of the metal cylindrical body A increases.

The present invention eliminates these drawbacks and improves valve guide 5.
The purpose of the present invention is to provide a valve stem seal which has better and more reliable attachment and fixing properties to the valve stem seal, and which can be removed from the valve guide 5 very easily.

The present invention, as shown in Figs. 3 and 4,
A valve stem seal in which a seal lip 1 made of an elastic body B such as synthetic rubber, which is in sliding contact with a valve stem 7, is integrally bonded above an inward flange part 3 formed on the upper part of a metal cylinder A; The metal cylindrical body A, which serves as a fitting portion with the valve guide 5, has a structure in which a plurality of convex portions 8 continuously protrude outward from the metal cylindrical body A at its lower portion.

When fitting the valve stem seal having this structure into the valve guide 5, as shown in FIG. using
A vertical pressing force is applied to the press-fitting jig 9 to make the fitting. At this time, the pressing force is applied to the convex portion 8, that is, the lower part of the metal cylindrical body A, and follows the upper part of the metal cylindrical body A. inserted. This means that the metal cylindrical body A does not lose its vertical orientation until the end of installation, and even if the valve guide 5 has a somewhat rough or distorted surface, the upper part of the metal cylindrical body A that follows will remain on that surface. Since it is inserted gently and press-fitted tightly, any installation defects are completely eliminated, and the metal cylindrical body A, which is highly secure in installation, greatly improves the efficiency of the fitting operation.

On the other hand, if it becomes necessary to remove the valve stem seal due to wear of the seal lip 1 or partial disassembly of the valve, the bottom surface of the convex portion 8 that protrudes at multiple locations can become a sufficiently wide protrusion. If it is easily hooked with a simple removal jig, or if it is stuck firmly, it can be turned circumferentially to loosen the resistance and then pulled upwards, making it extremely easy even for inexperienced workers. The secondary effects were also great, such as being able to carry out escape work.

Furthermore, since the protrusion 8 can be formed from the lower part by press working during the molding process of the metal cylinder A, the process is easy and the above-mentioned excellent effects are achieved without increasing the cost significantly.

As described above, the present invention is an ideal valve stem seal that has a simple structure, is extremely safe to install, and is easy to install and remove.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views of conventional valve stem seals. FIG. 3 is a sectional view showing an embodiment of the valve stem seal of the present invention. FIG. 4 is a perspective view of FIG. 3. FIG. 5 is a sectional view showing a state in which a conventional valve stem seal is installed. FIG. 6 is a sectional view showing a state in which the valve stem seal of the present invention is installed. A...Metal cylindrical body, B...Elastic body, 1...Seal lip, 3...Flange portion, 5...Valve guide, 7...Valve stem, 8...Protrusion, 9...Press fitting jig.

Claims (1)

[Scope of utility model registration request] In a valve stem seal in which a seal lip made of an elastic material such as synthetic rubber is bonded and integrated above an inward flange formed at the top of a metal cylindrical body and makes sliding contact with the valve stem; the fitting part with the valve guide. A valve stem seal characterized in that a metal cylindrical body has a plurality of protrusions partially protruding outward at its lower end.