JP3890750B2 - Valve stem seal - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve stem seal used for a valve stem of an intake / exhaust mechanism of an engine of an automobile or a general industrial machine, for example.
[0002]
[Prior art]
Conventionally, examples of this type of valve stem seal include those shown in FIGS. 4 and 5.
[0003]
FIG. 4 is a schematic cross-sectional view of a conventional valve stem seal. FIG. 5 is a schematic view showing a use state of the valve stem seal according to the prior art.
[0004]
As shown in FIG. 5, a valve stem 300 provided with a valve (not shown) for sucking and exhausting a port (not shown) provided on the P side (port for suction or exhaust), and the periphery thereof are surrounded. The valve stem seal 100 is used to seal the lubricating oil in the lubricating oil chamber while supplying an appropriate amount of lubricating oil to the extent that an oil film is formed in the annular gap with the valve guide 200.
[0005]
More specifically, one end side of the valve guide 200 faces the lubricating oil chamber side O in which lubricating oil is stored, and the other end side faces the port side P as described above.
[0006]
The valve stem 300 is reciprocally inserted into the valve guide 200, and the valve stem 300 reciprocates to open and close a port (not shown) by a valve to perform intake or exhaust. .
[0007]
As shown in FIG. 4, the valve stem seal 100 is generally composed of a metal ring 101 and a rubber-like elastic seal portion 102.
[0008]
The metal ring 101 includes a cylindrical portion 101a that is fitted to the outer periphery of the valve guide 200 and an inward flange portion 101b.
[0009]
The seal portion 102 is provided on the outer end surface side of the inward flange portion 101b, and seals a lip 102a that slidably seals on the outer peripheral surface of the reciprocating valve stem 300, and an inner end surface of the inward flange portion 101b. And an upper end seal portion 102b that seals the upper end surface of the valve guide 200, and an outer peripheral seal portion 102c that is provided on the inner periphery of the cylindrical portion 101a and seals the outer periphery of the valve guide 200.
[0010]
A metal garter spring 103 that increases the tension is attached to the outer periphery of the seal lip 102a.
[0011]
Further, like the valve stem seal shown in FIG. 6, a plurality of equally-spaced protrusions 102d are provided on the lower portion (port side P) of the seal lip 102a so that the lip can follow the eccentric dynamic movement of the valve stem 300. Some have improved performance and stabilized sealing performance.
[0012]
As a function of these valve stem seals, it is important that the lubricating oil in the lubricating oil chamber for lubricating the cam to the valve train portion inside the engine head does not leak to the intake or exhaust port.
[0013]
This is because when an oil leak occurs, the leaked oil burns, pollutes the exhaust gas and the exhaust system, further consumes the oil, and adversely affects the engine function.
[0014]
On the other hand, when completely sealed, the lubricity between the valve guide and the valve stem is lost, and seizure or galling occurs, resulting in problems such as breakage of the valve train.
[0015]
As described above, it is necessary to appropriately maintain the opposing functions of oil sealing and (minimum necessary) oil supply.
[0016]
[Problems to be solved by the invention]
However, in the case of the prior art as described above, the following problems have occurred.
[0017]
In the configuration of the valve stem seal according to the above-described prior art, depending on the engine characteristics, the pressure inside the port blows up to the seal portion, and the oil film between the valve guide and the valve stem and the oil film of the seal lip sliding portion are the upper part. As a result, both of them become insufficiently lubricated, and the wearability of the lip deteriorates, or seizure occurs between the valve guide and the valve stem, which may adversely affect the basic function of the engine.
[0018]
In recent years, with the increase in the number of valves, the lip design has been designed to minimize the oil film by adjusting the lip angle and the edge of the lip tip. Depending on the engine model or operating conditions, the valve guide Since there is a risk that the valve stem will be burnt out or galling due to insufficient oil amount, change the lip angle and edge state, and redesign by tuning to the optimum design on the seal side There were many things I had to do.
[0019]
The present invention has been made in order to solve the above-described problems of the prior art, and an object of the present invention is to make the sealing performance of the lubricating oil compatible with the supply performance of the lubricating oil and to easily adjust these. It is to provide a stem seal.
[0020]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, a valve guide having one end facing the lubricating oil chamber and the other end facing the port, and a valve stem disposed reciprocally in the valve guide, In the valve stem seal that seals the lubricating oil in the lubricating oil chamber while supplying lubricating oil that forms an oil film in the annular gap between
A seal lip that slidably contacts the valve stem surface in an annular shape,
Both are arranged at predetermined intervals in the lubricating oil chamber side slopes of the seal lip in the circumferential direction, the tip of the lip end extends axially to the end surface of the lubricating oil chamber side, from the lip tip to the end surface of the lubricating oil chamber side A plurality of projections whose entire surface is in sliding contact with the valve stem surface are provided.
[0021]
Therefore, the sealing performance against the lubricating oil in the lubrication chamber and the annular gap between the valve guide and the valve stem can be improved by increasing or decreasing the number of protrusions and the sliding contact shape (sliding contact area) of the protrusions on the valve stem surface. The supply amount of the lubricating oil can be easily adjusted, and the eccentric followability is improved by this protrusion.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.
[0023]
A valve stem seal according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.
[0024]
FIG. 1 is a schematic sectional view of a valve stem seal according to an embodiment of the present invention, and FIG. 2 is a partial perspective view seen from the direction of arrow V in FIG.
[0025]
The valve stem seal according to the embodiment of the present invention, as described in the above-mentioned prior art, is a suction port (not shown) (intake or exhaust port) provided on the (P) side in FIG.・ Supply an appropriate amount of lubricating oil to the extent that an oil film is formed in an annular gap between a valve stem (not shown) provided with a valve (not shown) for exhaust and a valve guide (not shown) surrounding the valve stem. However, it is used to seal the lubricating oil in the lubricating oil chamber.
[0026]
Since the configuration and function of the valve guide and the valve stem have been described in the above-described prior art, description thereof will be omitted.
[0027]
As shown in FIG. 1, the valve stem seal 1 according to the present embodiment is generally composed of a metal ring 2 and a rubber-like elastic seal portion 3.
[0028]
The metal ring 2 includes a cylindrical portion 2a and an inward flange portion 2b that are fitted to the outer periphery of the valve guide.
[0029]
The seal portion 3 is provided on the outer end surface side of the inward flange portion 2b, and seals the seal lip 3a that slidably seals on the outer peripheral surface of the reciprocating valve stem, and the inner end surface of the inward flange portion 2b. An upper end surface seal portion 3b that seals the upper end surface of the valve guide is provided, and an outer peripheral seal portion 3c that is provided on the inner periphery of the cylindrical portion 2a and seals the outer periphery of the valve guide.
[0030]
A metal garter spring 4 for increasing the tension is mounted on the outer periphery of the seal lip 3a.
[0031]
In the present embodiment, the projection 3d is provided.
[0032]
A plurality of the protrusions 3d are arranged on the inclined surface of the seal lip 3a on the lubricating oil chamber side O at a predetermined interval in the circumferential direction as shown in FIG.
[0033]
Further, the protrusion 3 d is formed so as to extend in the axial direction from the lip tip of the seal lip 3 a toward the lubricating oil chamber side O, and extends to the upper end surface 3 e of the seal portion 3.
[0034]
Therefore, the tip of the projection 3d also slides on the outer peripheral surface of the valve stem in the same manner as the lip tip of the seal lip 3a.
[0035]
Note that the shape and the like of the protrusion 3d may be set as appropriate in consideration of ease of manufacture, stability, and the like. For example, as shown in FIG.
[0036]
Here, with respect to the width W shown in FIG. 1 relating to the number of protrusions 3d installed and the contact area of the protrusions 3d to the outer peripheral surface of the valve stem, the lubrication supplied to the annular gap between the valve stem and the valve guide. It can be set according to the required amount of oil.
[0037]
That is, as the number of installations is increased or the width W is increased, the supply amount is increased.
[0038]
For example, for a width W of about 0.2 to 0.3 mm (the joining width of the seal lip 3a to the inclined surface of the lubricating oil chamber side O is about 1 to 2 mm), the width W is 0.4 to 0. If it is about 6 mm, the supply amount doubles.
[0039]
Further, as the number of installations increases, a more uniform oil film can be formed. Therefore, it is more preferable to increase the number of installations by increasing the number of installations while keeping the width W small.
[0040]
In addition, although the arrangement position of the protrusion 3d is not particularly limited, it goes without saying that a uniform oil film formation and a more uniform follow-up of the seal lip 3a can be achieved by providing the protrusions 3d equally.
[0041]
As described above, since the supply amount of the lubricating oil can be adjusted by adjusting the number of the projections 3d installed, the sealing performance of the lubricating oil and the supply performance of the lubricating oil can be compatible.
[0042]
Then, as with the prior art, the supply amount of the lubricating oil can be easily adjusted only by adjusting the number of protrusions 3d, etc. without any technical difficulties in terms of design such as lip angle adjustment. it can.
[0043]
Further, since the valve guide is supported in the vicinity of the lip by the protrusion 3d, the eccentricity followability is improved, the sealing performance is further stabilized, the lip wear is suppressed, and the durability is improved.
[0044]
As shown in FIG. 3, the above-described configuration can be applied to a configuration in which the metal ring 2 includes the outward flange portion 2c for the function of attaching the valve stem seal to a predetermined position. It is.
[0045]
【The invention's effect】
As described above, the present invention is arranged at a predetermined interval in the circumferential direction on the lubricant chamber side slope of the seal lip that is slidably contacted with the valve stem surface in an annular direction, and is substantially from the tip of the lip toward the lubricant chamber side. By providing a plurality of protrusions that extend in the axial direction and make sliding contact with the valve stem surface, the number of protrusions can be increased or decreased, and the shape of the protrusions that slide onto the valve stem surface (sliding contact area) can be reduced. Adjustment of the sealing performance and the amount of lubricating oil supplied to the annular gap between the valve guide and the valve stem can be made simple, and the eccentric followability is improved by this protrusion.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a valve stem seal according to an embodiment of the present invention.
FIG. 2 is a partial perspective view seen from the direction of arrow V in FIG.
FIG. 3 is a schematic sectional view of a valve stem seal according to an embodiment of the present invention.
FIG. 4 is a schematic sectional view of a valve stem seal according to the prior art.
FIG. 5 is a schematic view showing a use state of a valve stem seal according to the prior art.
FIG. 6 is a schematic sectional view of a conventional valve stem seal.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Valve stem seal 2 Metal ring 2a Cylindrical part 2b Inward flange part 2c Outward flange part 3 Seal part 3a Seal lip 3b Upper end surface seal part 3d Protrusion 3e Upper end surface 4 Metal garter spring

Claims (1)

Supplying lubricating oil that forms an oil film in an annular gap between a valve guide with one end facing the lubricating oil chamber and the other end facing the port, and a valve stem that is reciprocally movable within the valve guide However, in the valve stem seal that seals the lubricating oil in the lubricating oil chamber,
A seal lip that slidably contacts the valve stem surface in an annular shape,
Both are arranged at predetermined intervals in the lubricating oil chamber side slopes of the seal lip in the circumferential direction, the tip of the lip end extends axially to the end surface of the lubricating oil chamber side, from the lip tip to the end surface of the lubricating oil chamber side A valve stem seal comprising a plurality of protrusions whose entire surface is in sliding contact with the valve stem surface.

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