JP2009281410A - Valve stem seal and valve stem seal system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve stem seal and a valve stem seal system with excellent durability and efficiency of assembling work. <P>SOLUTION: The valve stem seal system is provided with a valve stem guide 200 having an insertion hole to which a valve stem 300 is inserted and guiding the valve stem 300 by a guide face 210 constituted by part of the inner peripheral face of the insertion hole and with the valve stem seal 100 fixed to the valve stem guide 200. An annular recessed part 220 having an inside diameter larger than that of the guide face 210 is provided at the chip of the valve stem guide 200, and a female screw part 221 is formed on the inner peripheral face of the annular recessed part 220. The valve stem seal 100 is provided with a lip part 120 brought into slidable contact with the outer peripheral surface of the valve stem 300 and a male screw part 111 screwed to the female screw part 221, and includes a resin material. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a valve stem seal and a valve stem seal system.

  An intake / exhaust valve mechanism in an internal combustion engine is provided with a valve stem seal that seals an annular gap between an insertion hole provided in a valve stem guide and a valve stem inserted through the insertion hole (patent) References 1 and 2). With reference to FIG. 4, a conventional valve stem seal and a valve stem seal system to which the valve stem seal is applied will be described. FIG. 4 is a schematic cross-sectional view of a conventional valve stem seal system.

  As illustrated, the valve stem 400 is configured to be inserted into an insertion hole provided in the valve stem guide 500 and guided by the inner peripheral surface of the insertion hole. Here, (O) in the figure is the lubricating oil chamber side, and (P) is the port (intake port or exhaust port) side. In order to seal the lubricating oil in the lubricating oil chamber while supplying an appropriate amount of lubricating oil to such an extent that an oil film is formed in the annular gap between the insertion hole provided in the valve stem guide 500 and the valve stem 400. In addition, a valve stem seal is provided.

  The valve stem seal according to this conventional example includes a rubber stem elastic valve stem seal body 600 and a metal reinforcing ring 610. The valve stem seal body 600 is integrally formed with the reinforcing ring 610. In the valve stem seal configured as described above, the inner peripheral surface 601 of the cylindrical portion fixed to the inner peripheral surface of the reinforcing ring 610 in the valve stem seal body 600 is fitted and fixed to the valve stem guide 500. The

  In the valve stem seal configured as described above, sludge generated as the lubricating oil deteriorates with time causes the sealing performance to deteriorate. That is, sludge generated in the lubricating oil adheres to the valve stem seal body 600 and accumulates and adheres over time. When the accumulated sludge is hardened, the lip at the tip of the valve stem seal body 600 and the spring provided on the outer peripheral side to press the lip tip against the outer peripheral surface of the valve stem 400 do not exhibit the original behavior. . Therefore, the original function of the lip and the spring is not exhibited, and the sealing performance is deteriorated.

Reference 2 discloses a technique in which a seal lip made of a fluororesin that does not adhere sludge is disclosed as a seal lip that slides on the valve stem in order to eliminate problems caused by sludge. However, in the technique disclosed in the cited document 2, a reinforcing ring, a seal lip made of a fluororesin, and a rubber elastic member for fitting (attaching) to the valve stem guide are integrally configured. Has been. For this reason, there are problems that the number of parts is large, technical difficulties are involved in molding, and workability is poor.
Japanese Utility Model Publication No. 60-1903 Japanese Patent No. 3902804

  An object of the present invention is to provide a valve stem seal and a valve stem seal system having excellent durability and excellent assembly workability.

  The present invention employs the following means in order to solve the above problems.

That is, the valve stem seal of the present invention is
In the valve stem seal fixed to the valve stem guide that guides the valve stem,
A lip that slidably contacts the outer peripheral surface of the valve stem;
A male screw portion screwed to a female screw portion provided on the inner peripheral surface of the valve stem guide;
With
It is composed of a resin material.

Further, in a valve stem seal fixed to a valve stem guide for guiding another valve stem seal valve stem of the present invention,
A lip that slidably contacts the outer peripheral surface of the valve stem;
A female screw portion screwed to a male screw portion provided on the outer peripheral surface of the valve stem guide;
With
It is composed of a resin material.

The valve stem seal system of the present invention is
A valve stem guide having an insertion hole through which the valve stem is inserted, and guiding the valve stem by a guide surface constituted by a part of the inner peripheral surface of the insertion hole;
A valve stem seal system comprising: a valve stem seal fixed to the valve stem guide;
An annular recess having an inner diameter larger than the inner diameter of the guide surface is provided at the tip of the valve stem guide, and an internal thread portion is provided on the inner peripheral surface of the annular recess,
The valve stem seal includes a lip portion that slidably contacts an outer peripheral surface of the valve stem and a male screw portion that is screwed to the female screw portion, and is made of a resin material.

  In the valve stem seal, the inner diameter of the substantially cylindrical portion having the male thread portion provided on the outer peripheral surface thereof may be substantially the same as the inner diameter of the guide surface of the valve stem guide.

  As a result, the substantially cylindrical portion of the valve stem seal is sandwiched between the inner peripheral surface of the valve stem guide and the outer peripheral surface of the valve stem.

Another valve stem seal system of the present invention is:
A valve stem guide having an insertion hole through which the valve stem is inserted, and guiding the valve stem by a guide surface constituted by at least a part of the inner peripheral surface of the insertion hole;
A valve stem seal system comprising: a valve stem seal fixed to the valve stem guide;
A male screw portion is provided on the outer peripheral surface of the valve stem guide,
The valve stem seal includes a lip portion that slidably contacts an outer peripheral surface of the valve stem and a female screw portion that is screwed to the male screw portion, and is made of a resin material.

  Here, the resin material is preferably a fluororesin, and particularly preferably polytetrafluoroethylene.

As described above, according to each of the above-described inventions, the valve stem seal is made of a resin material (as described above, fluororesin (especially polytetrafluoroethylene) is suitable), so that the sludge is the valve stem. It can prevent adhering to the seal. Accordingly, it is possible to suppress a decrease in sealing performance due to sludge adhesion and improve durability. Since the valve stem seal is fixed to the valve stem guide by screwing, the valve stem seal system can be obtained by a simple assembly operation.

  As described above, according to the present invention, durability can be improved and assembly workability can be improved.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .

Example 1
A valve stem seal and a valve stem seal system according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view of a valve stem seal according to a first embodiment of the present invention.

<Overall configuration of valve stem seal system>
The overall configuration of the valve stem seal system according to the first embodiment will be described. As shown in the figure, the valve stem 300 is inserted into an insertion hole provided in the valve stem guide 200 made of a hard material such as metal, and a guide surface 210 constituted by a part of the inner peripheral surface of the insertion hole. Configured to be guided by.

  Here, (O) in the figure is the lubricating oil chamber side, and (P) is the port (intake port or exhaust port) side. The lubricating oil in the lubricating oil chamber is sealed while supplying an appropriate amount of lubricating oil to the extent that an oil film is formed in the annular gap between the guide surface 210 provided on the valve stem guide 200 and the valve stem 300. For this purpose, a valve stem seal 100 is provided. The valve stem seal 100 according to the present embodiment is made of a resin material having a property that sludge generated with the aging of the lubricating oil does not adhere. A suitable example of the resin material is PTFE (polytetrafluoroethylene).

  As a function of the valve stem seal 100, it is important to prevent the lubricating oil in the lubricating oil chamber from leaking into the intake port and the exhaust port. This is because when an oil leak occurs, the leaked oil burns, pollutes the exhaust gas and the exhaust system, consumes more oil, and adversely affects the engine function. On the other hand, when completely sealed, the lubricity between the valve stem guide 200 and the valve stem 300 is lost, and seizure or galling occurs, causing problems such as breakage of the valve train. Therefore, as described above, the valve stem seal 100 is configured to supply an appropriate amount of lubricating oil to such an extent that an oil film is formed in the annular gap between the guide surface 210 and the valve stem 300.

<Details of members constituting the valve stem seal system>
The valve stem seal 100 and the valve stem guide 200 constituting the valve stem seal system according to the first embodiment will be described in detail.

An annular recess 220 whose inner diameter is larger than the inner diameter of the guide surface 210 is provided at the tip of the valve stem guide 200. An internal thread portion 221 is provided on the inner peripheral surface of the annular recess 220. In addition, the inner diameter of the guide surface 210 in the valve stem guide 200 is set to be slightly larger than the outer diameter of the valve stem 300. This
The valve stem 300 is guided by the valve stem guide 200 as the outer peripheral surface of the valve stem 300 slides with respect to the guide surface 210.

  The valve stem seal 100 includes a substantially cylindrical portion 110 fixed to the valve stem guide 200, a lip portion 120 whose diameter decreases from the substantially cylindrical portion 110 toward the distal end, and a connection between the substantially cylindrical portion 110 and the lip portion 120. And an outward flange portion 130 provided in the vicinity of the portion. The valve stem seal 100 is a single member obtained by resin molding, and the substantially cylindrical portion 110, the lip portion 120, and the outward flange portion 130 are integrated.

  The inner diameter of the substantially cylindrical portion 110 of the valve stem seal 100 is substantially the same as the inner diameter of the guide surface 210 of the valve stem guide 200 (that is, slightly larger than the outer diameter of the valve stem 300). Is set).

  In FIG. 1, the valve stem seal system shows a state where no external force is acting (that is, a state where the valve stem 300 is not inserted). However, in FIG. 1, the valve stem 300 is indicated by a dotted line in order to clarify the dimensional relationship with the valve stem 300. In a state where the valve stem 300 is inserted, the lip portion 120 is deformed so that the tip thereof is expanded, and the tip contacts the outer peripheral surface of the valve stem 300 with an appropriate pressure by the elastic restoring force. It will be in the state. As a result, the tip of the lip portion 120 is slidably in contact with the outer peripheral surface of the valve stem 300 and is moderate enough to form an oil film in the annular gap between the guide surface 210 and the valve stem 300. It is possible to seal the lubricating oil in the lubricating oil chamber while supplying an appropriate amount of lubricating oil.

  On the outer peripheral surface of the substantially cylindrical portion 110 of the valve stem seal 100, a male screw portion 111 that is screwed to a female screw portion 221 provided on the inner peripheral surface of the annular recess 220 of the valve stem guide 200 is provided. As a result, the valve stem seal 100 can be fixed to the valve stem guide 200 simply by screwing the substantially cylindrical portion 110 of the valve stem seal 100 into the annular recess 220 of the valve stem guide 200. At this time, if the valve stem seal 100 is screwed in until the outward flange portion 130 provided on the valve stem seal 100 hits the tip of the valve stem guide 200, the valve stem seal 100 can be positioned at a desired position. .

<Excellent points of this embodiment>
According to the valve stem seal 100 and the valve stem seal system comprising the valve stem seal 100 and the valve stem guide 200 according to the present embodiment, the valve stem seal 100 is made of a material having a property that sludge does not adhere. . Therefore, it is possible to suppress a decrease in sealing performance accompanying sludge adhesion. That is, it can be prevented that the sludge adheres to and adheres to the valve stem seal 100 and adversely affects the behavior of the lip portion 120. Accordingly, it is possible to suppress a decrease in sealing performance and improve durability.

  Further, in this embodiment, the valve stem seal system is configured by only two members of the valve stem seal 100 and the valve stem guide 200, and the number of parts can be reduced. Moreover, the valve stem seal system can be obtained by a simple assembly operation in which the valve stem seal 100 is screwed into the valve stem guide 200 until it abuts against the tip of the valve stem guide 200.

In general, it is technically difficult to integrally form members made of different materials, such as integrally forming a member made of a rubber material and a member made of a resin material into a metal member. Accompanying sex. On the other hand, in the case of the present embodiment, as described above, only by screwing work,
Since the valve stem seal 100 made of resin and the valve stem guide 200 made of a hard material such as metal can be fixed, the productivity can be improved and the cost can be reduced.

  Here, although the valve stem seal 100 according to the present embodiment generally employs a resin material having a low resilience (low resilience) as compared with a rubber material, the valve stem seal 100 is attached to the valve stem guide 200 by a screw fastening force. Since the fixing structure is employed, a fixing force equal to or higher than that when a rubber material is used for the fitting portion can be obtained.

  Although fixing using a locking force can be considered, in that case, it is difficult to obtain a sufficient fixing force. This point will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view of a valve stem seal system according to a comparative example.

  In the illustrated example, an annular locking protrusion 251 protruding outward is provided near the tip of the valve stem guide 250. The valve stem seal 150 includes a substantially cylindrical portion 160 fixed to the valve stem guide 250 and a lip portion 170 whose diameter decreases from the substantially cylindrical portion 160 toward the distal end. An annular locking protrusion 161 protruding inward is provided at the tip of the substantially cylindrical portion 160.

  According to the valve stem seal system configured as described above, the engagement protrusion 161 and the engagement protrusion 251 provided on the valve stem seal 150 can be obtained by simply fitting the substantially cylindrical portion 160 of the valve stem seal 150 into the valve stem guide 250. Therefore, the valve stem seal 150 can be fixed to the valve stem guide 250.

  Such a fixing method is effective when the valve stem seal 150 is made of a rubber material. However, as described above, resin materials are generally less recoverable than rubber materials, and plastic deformation and settling are likely to occur. Therefore, it is difficult to obtain a stable fixing force by the fixing method using the locking protrusion as shown in FIG. In contrast to the method of fixing only the locking protrusion as shown in FIG. 2 (a), as shown in FIG. 2 (b), the locking protrusion 161 is directed inward on the outer peripheral side of the substantially cylindrical portion 160. It is also conceivable to attach a snap ring (or spring) S to be pressed. However, this is still insufficient for the valve stem seal 150 using a resin material having low recoverability.

  In the present embodiment, the inner diameter of the substantially cylindrical portion 110 of the valve stem seal 100 is substantially the same as the inner diameter of the guide surface 210 of the valve stem guide 200 (that is, the valve stem 300). Is set so that it is slightly larger than the outer diameter. Accordingly, the substantially cylindrical portion 110 in the valve stem seal 100 is sandwiched between the inner peripheral surface of the annular recess 220 and the outer peripheral surface of the valve stem 300 in the valve stem guide 200, so that the valve stem seal 100 can be It is possible to more reliably prevent the stem guide 200 from being detached.

(Example 2)
A valve stem seal and a valve stem seal system according to a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic sectional view of a valve stem seal according to the second embodiment of the present invention. In the first embodiment, the screw fastening is provided by providing the screw stems on the inner peripheral surface of the valve stem guide and the outer peripheral surface of the valve stem seal, respectively. However, in this embodiment, the outer peripheral surface of the valve stem guide and the valve The structure which carries out screw fastening by providing a thread part in the inner peripheral surface of a stem seal is shown. Since the basic configuration is the same as that of the first embodiment, the description thereof will be omitted as appropriate.

<Overall configuration of valve stem seal system>
A configuration of the entire valve stem seal system according to the second embodiment will be described. As shown in the figure, the valve stem 300 is inserted through an insertion hole provided in a valve stem guide 200a made of a hard material such as metal, and is guided by a guide surface 210a constituted by an inner peripheral surface of the insertion hole. Configured to be

  Here, (O) in the figure is the lubricating oil chamber side, and (P) is the port (intake port or exhaust port) side. A valve stem seal 100a is fixed to the valve stem guide 200a. The role and function of the valve stem seal 100a are as described in the first embodiment. Further, the valve stem seal 100a according to the present embodiment is also made of a resin material having a property that sludge generated with the deterioration of the lubricating oil with time does not adhere.

<Details of members constituting the valve stem seal system>
The valve stem seal 100a and the valve stem guide 200a constituting the valve stem seal system according to the second embodiment will be described in detail.

  A male screw portion 210b is provided on the outer peripheral surface near the tip of the valve stem guide 200a. Further, the inner diameter of the guide surface 210 a in the valve stem guide 200 a is set to be slightly larger than the outer diameter of the valve stem 300. Thereby, the valve stem 300 is guided by the valve stem guide 200a because the outer peripheral surface of the valve stem 300 slides with respect to the guide surface 210a.

  The valve stem seal 100a includes a substantially cylindrical portion 110a that is fixed to the valve stem guide 200a, and a lip portion 120a that decreases in diameter from the substantially cylindrical portion 110a toward the distal end. The valve stem seal 100a is a single member obtained by resin molding, and the substantially cylindrical portion 110a and the lip portion 120a are integrated.

  In FIG. 3, the valve stem seal system shows a state where no external force is acting (that is, a state where the valve stem 300 is not inserted). However, in FIG. 3, the valve stem 300 is indicated by a dotted line in order to clarify the dimensional relationship and the like with the valve stem 300. In the state where the valve stem 300 is inserted, the lip portion 120a is deformed so that the diameter of the lip portion 120a expands, and the distal end of the lip portion 120a comes into contact with the outer peripheral surface of the valve stem 300 with an appropriate pressure. It will be in the state. As a result, the tip of the lip portion 120a comes into contact with the outer peripheral surface of the valve stem 300 in a slidable state, and is moderate enough to form an oil film in the annular gap between the guide surface 210a and the valve stem 300. It is possible to seal the lubricating oil in the lubricating oil chamber while supplying an appropriate amount of lubricating oil.

  An internal thread 111a that is screwed to an external thread 210b provided on the outer peripheral surface of the valve stem guide 200a is provided on the inner peripheral surface of the substantially cylindrical part 110a of the valve stem seal 100a. Accordingly, the valve stem seal 100a can be fixed to the valve stem guide 200a only by screwing the substantially cylindrical portion 110a of the valve stem seal 100a into the tip portion of the valve stem guide 200a. At this time, if the valve stem seal 100a is screwed in until the end face 120b of the lip 120a of the valve stem seal 100a hits the tip of the valve stem guide 200a, the valve stem seal 100a can be positioned at a desired position. .

  With the above configuration, the same effects as in the first embodiment can be obtained in this embodiment.

FIG. 1 is a schematic cross-sectional view of a valve stem seal according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of a valve stem seal system according to a comparative example. FIG. 3 is a schematic sectional view of a valve stem seal according to the second embodiment of the present invention. FIG. 4 is a schematic cross-sectional view of a conventional valve stem seal system.

Explanation of symbols

100, 100a Valve stem seal 110, 110a Substantially cylindrical part 111 Male thread part 111a Female thread part 120, 120a Lip part 120b End face 130 Outward flange part 150 Valve stem seal 160 Substantially cylindrical part 161 Locking projection 170 Lip part 200, 200a Valve stem Guide 210b Male thread portion 210, 210a Guide surface 220 Annular recess 221 Female thread portion 250 Valve stem guide 251 Locking projection 300 Valve stem

Claims (7)

In the valve stem seal fixed to the valve stem guide that guides the valve stem,
A lip that slidably contacts the outer peripheral surface of the valve stem;
A male screw portion screwed to a female screw portion provided on the inner peripheral surface of the valve stem guide;
With
A valve stem seal comprising a resin material. In the valve stem seal fixed to the valve stem guide that guides the valve stem,
A lip that slidably contacts the outer peripheral surface of the valve stem;
A female screw portion screwed to a male screw portion provided on the outer peripheral surface of the valve stem guide;
With
A valve stem seal comprising a resin material.   The valve stem seal according to claim 1 or 2, wherein the resin material is polytetrafluoroethylene. A valve stem guide having an insertion hole through which the valve stem is inserted, and guiding the valve stem by a guide surface constituted by a part of the inner peripheral surface of the insertion hole;
A valve stem seal system comprising: a valve stem seal fixed to the valve stem guide;
An annular recess having an inner diameter larger than the inner diameter of the guide surface is provided at the tip of the valve stem guide, and an internal thread portion is provided on the inner peripheral surface of the annular recess,
The valve stem seal includes a lip portion that slidably contacts an outer peripheral surface of the valve stem and a male screw portion that is screwed to the female screw portion, and is made of a resin material. system.   2. The valve stem seal according to claim 1, wherein an inner diameter of a substantially cylindrical portion having the male screw portion provided on an outer circumferential surface thereof is substantially the same as an inner diameter of a guide surface in the valve stem guide. 5. The valve stem seal system according to 4. A valve stem guide having an insertion hole through which the valve stem is inserted, and guiding the valve stem by a guide surface constituted by at least a part of the inner peripheral surface of the insertion hole;
A valve stem seal system comprising: a valve stem seal fixed to the valve stem guide;
A male screw portion is provided on the outer peripheral surface of the valve stem guide,
The valve stem seal includes a lip portion that slidably contacts an outer peripheral surface of the valve stem, and a female screw portion that is screwed to the male screw portion, and is made of a resin material. system.   The valve stem seal system according to claim 4, 5 or 6, wherein the resin material is polytetrafluoroethylene.

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