JP2016070392A - Seal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal device having a structure in which the seal device is easily installed at a guide member, after installation, the seal device is hardly dropped off from the guide member and a return part arranged at the end part of the metallic ring of the seal device is hardly deformed in plastic.SOLUTION: This invention relates to a seal device in which a shaft member is inserted and passed in an inner diameter shaft hole at a cylindrical part and installed at a guide member provided with an engaging groove at either an outer diameter part or an inner diameter part. It has a metallic ring arranged at either the outer diameter part or the inner diameter part of the guide member and a rubber-like resilient body covered on the metallic ring. There are provided a lip part sliding and contacted with the outer diameter part of the shaft member and a fitting rubber part pressed and fitted at either the outer diameter part or the inner diameter part with a prescribed fitting margin by the rubber-like resilient body. In addition, the end part of the metallic ring is provided with a return part, the return part is engaged with the engaging groove, and a return inner surface rubber part is arranged between the cylindrical part of the metallic ring and the return part.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sealing device according to a sealing technique, and more particularly to a sealing device having a lip portion slidably in close contact with a shaft member. The sealing device of the present invention is used as, for example, a valve stem seal used for an intake valve or an exhaust valve of an internal combustion engine.

  Conventionally, valve stem seals have been used in internal combustion engines such as gasoline engines and diesel engines for the purpose of valve stem lubrication and engine oil consumption reduction. In recent years, the demand for fuel saving due to environmental protection has been increasing, and the need to install a turbocharger or the like has been increasing so that a large torque can be generated when necessary in a small combustion chamber volume. When an internal combustion engine is operated using a supercharger, a higher intake pressure is applied to the valve stem seal than when a supercharger is not installed, and a higher exhaust pressure is applied due to fuel combustion.

  As this type of prior art, for example, there are valve stem seals 101 and 102 shown in FIG. 4 (a) or (b). A valve stem seal 101 shown in FIG. 4A includes a metal ring 111 fitted to the outer diameter side of a valve stem guide 141 that passes through the valve stem 131, and a rubber-like elastic body attached to the metal ring 111. 121, and the rubber-like elastic body 121 is fitted to the outer diameter surface of the valve stem 131 and the lip portion 122 slidably in close contact with the outer diameter surface of the valve stem 131 with a predetermined fitting allowance. The fitting rubber portion 125 is integrally formed. Further, the valve stem seal 102 shown in FIG. 4 (b) is obtained by omitting the fitting rubber portion 125 from the configuration of the valve stem seal 101 of FIG. 4 (a). 141 is configured to be fitted directly to the outer diameter surface of 141.

  However, in the valve stem seal 101 shown in FIG. 4A, the fitting rubber portion 125 made of the rubber-like elastic body 121 is only fitted to the outer diameter surface of the valve stem guide 141 with a predetermined fitting allowance. When a high pressure is applied to the valve stem seal 101 from below in the drawing as indicated by the arrow x, the valve stem seal 101 may fall off the valve stem guide 141 (seal dropout problem). Further, in the valve stem seal 102 shown in FIG. 4B, since the metal ring 111 is firmly fitted to the valve stem guide 141, as shown by the arrow x, even if a high pressure is applied from below in the figure, the valve The stem seal 102 is difficult to drop off from the valve stem guide 141, but on the other hand, a large load is required when the valve stem seal 102 is attached to the valve stem guide 141, and special equipment for applying this large load is required. (Seal installation workability problem).

Japanese Utility Model Publication 4-33367

  The present invention has been made in view of the above points, and it is easy to attach the sealing device to the guide member. After the attachment, the sealing device is not easily detached from the guide member, and is provided at the end of the metal ring of the sealing device. An object of the present invention is to provide a sealing device having a structure in which the portion is difficult to be plastically deformed.

  The sealing device according to claim 1 of the present invention is attached to a guide member in which an axial member is inserted into the inner diameter shaft hole of the cylindrical portion and an engagement groove is provided in the outer diameter portion or the inner diameter portion of the cylindrical portion. A sealing device, comprising: a metal ring disposed on an outer diameter side or an inner diameter side of the guide member; and a rubber-like elastic body attached to the metal ring. In the sealing device provided with a lip portion that is in sliding contact with the outer diameter portion of the member, and a fitting rubber portion that is press-fitted with a predetermined fitting allowance to the outer diameter portion or the inner diameter portion of the guide member, A return portion is provided at an end portion, the return portion engages with the engagement groove, and a return inner rubber portion is provided between the cylindrical portion of the metal ring and the return portion. Is.

  According to the above invention, when the sealing device is attached to the guide member, the return portion is elastically deformed, so that the sealing device can be easily attached to the guide member, and after the attachment, the return portion is engaged with the engagement groove. The device does not easily fall off the guide member. In addition, since the return inner rubber portion is provided between the cylindrical portion and the return portion of the metal ring, the return inner rubber portion is elastically deformed together with the return portion, and exhibits a backup action against the elastic deformation of the return portion. Therefore, it becomes difficult to cause plastic deformation in the return portion. In addition, when the return inner rubber portion comes into contact with the inner surface of the engaging groove after mounting, the return inner rubber portion can also seal between the cylindrical portion of the metal ring and the guide member.

  The sealing device according to claim 2 of the present invention is the sealing device according to claim 1, wherein a taper portion is formed from an end portion of the guide member to an outer diameter portion or an inner diameter portion. It is.

  According to the above invention, since the return portion is guided along the tapered portion when the sealing device is attached to the guide member, positioning is facilitated. Therefore, mounting workability can be improved.

  The sealing device according to claim 3 of the present invention is the sealing device according to claim 1 or 2, wherein the rubber-like elastic body includes the lip portion, the fitting rubber portion, and the return inner surface rubber portion. It is characterized by being integrally formed.

  According to the above invention, since the lip portion, the fitting rubber portion, and the return inner surface rubber portion are integrated, they can be molded together with the molding die. Therefore, since it is not necessary to set a plurality of sprues or gates in the mold, it is possible to prevent the structure of the mold from becoming complicated even if a return inner rubber portion is provided in the sealing device.

  According to the present invention, the sealing device can be easily attached to the guide member, and the sealing device is less likely to drop off from the guide member after installation, and the return portion provided at the end of the metal ring of the sealing device is not easily plastically deformed. A structural sealing device can be provided.

It is a half section view of the sealing device (valve stem seal) concerning the example of the present invention. It is a half section view which shows the state after mounting | wearing with the sealing device (valve stem seal). It is explanatory drawing which shows the mounting procedure of the sealing device (valve stem seal). It is a half cut sectional view of the sealing device (valve stem seal) concerning a conventional example. It is a half section view of the sealing device (valve stem seal) concerning a reference example.

  Next, an embodiment when the present invention is applied as a valve stem seal will be described with reference to the drawings. For convenience of explanation, first, a corresponding reference example will be described, and then the embodiment will be described.

Reference example ...
FIG. 5 shows a valve stem seal 103 according to a reference example. In this valve stem seal 103, one end (upper end in the figure) of a metal ring 111 attached to the outer diameter side of a valve stem guide 141 that passes through the valve stem 131 is shown. A lip portion 122 made of a rubber-like elastic body is provided at the same time, and a return portion 112 is provided at the other end (lower end in the figure) of the metal ring 111. The return portion 112 is integrally formed with the metal ring 111 by bending the end portion of the metal ring 111 toward the inner diameter side over an angle range of 90 degrees or more as shown in the figure. Is configured to engage with an engagement groove 142 provided on the outer diameter surface of the valve stem guide 141.

  Therefore, in this reference example, when a high pressure acts on the valve stem seal 103 from below in the drawing as indicated by the arrow x, the return portion 112 is engaged with the engagement groove 142 provided on the outer diameter surface of the valve stem guide 141. Therefore, it is possible to prevent the metal ring 111 and the entire valve stem seal 103 from dropping from the valve stem guide 141.

  However, in this reference example, when the metal ring 111 is mounted on the outer diameter side of the valve stem guide 141, the return portion 112 is deformed alone, so that the return portion 112 is plastically deformed and its springiness is reduced. (Problem of plastic deformation of the return part).

Example···
Therefore, in the embodiment of the present invention, the valve stem seal 1 is configured as follows.

  FIG. 1 shows a half cut section of a valve stem seal 1 according to an embodiment of the present invention. FIG. 2 shows a state in which the valve stem seal 1 is attached to a valve stem guide 41, and FIG. Is shown. In each figure, the upper side is a cam chamber side A where a cam (not shown) is located, and the lower side is a port side (back pressure side) B where an intake / exhaust port (not shown) is located.

  As shown in FIG. 2, the valve stem guide 41 to which the valve stem seal 1 is attached has a cylindrical portion 42 having an inner diameter axial hole through which the valve stem 31 is inserted so as to reciprocate in the axial direction (vertical direction in the figure). The metal ring 11 of the valve stem seal 1 is fitted to the outer diameter side of the cylindrical portion 42. An annular engagement groove 43 is provided on the outer diameter surface of the cylindrical portion 42, and one end in the axial direction from the other end in the axial direction extends from one end surface (cam chamber side) of the cylindrical portion 42 to the outer diameter surface. An annular taper portion 44 is provided in such a direction that the outer diameter dimension gradually increases toward the port side.

  As shown in FIGS. 1 and 2, the valve stem seal 1 includes a metal ring 11 fitted to the outer diameter side of the valve stem guide 41, and a rubber-like material attached (vulcanized and bonded) to the metal ring 11. The rubber-like elastic body 21 has a lip portion 22 composed of a seal lip 23 and a back pressure lip 24 slidably in close contact with the outer diameter surface of the valve stem 31, and the valve stem guide 41. A fitting rubber portion 25 that is fitted to the outer diameter surface with a predetermined fitting allowance is integrally formed.

  The metal ring 11 is formed by integrally forming a flange portion 13 radially inward at one axial end of the cylindrical portion 12, and a fitting rubber portion 25 is attached to the inner diameter surface of the cylindrical portion 12. In addition, a seal lip 23 and a back pressure lip 24 are held on the inner diameter portion of the flange portion 13. A garter spring 26 for adjusting the tightening margin is fitted to the seal lip 23. The back pressure lip 24 is disposed on the other side in the axial direction of the seal lip 23, and its lip end is formed on the other side in the axial direction and obliquely inward in the radial direction, and its outer diameter surface is a pressure receiving surface for back pressure. It is said that.

  A return portion 14 is integrally formed at the other end portion in the axial direction of the cylindrical portion 12 of the metal ring 11. The return portion 14 is formed by bending the end portion of the cylindrical portion 12 of the metal ring 11 radially inward and obliquely toward one axial direction, and is formed in an annular shape when mounted. The front end portion 14a is engaged with the inner surface of the engagement groove 43. The thickness of the return portion 14 is formed to be thinner (smaller) than the thickness of the cylindrical portion 12.

  Further, a return inner surface rubber portion 27 is provided between the return portion 14 and the cylindrical portion 12 on the inner surface side (outer diameter side) of the return portion 14. The return inner rubber portion 27 is formed in an annular shape and filled so as to completely fill the space between the return portion 14 and the cylindrical portion 12, and is attached to the inner diameter surface of the cylindrical portion 12, or the inner diameter surface of the cylindrical portion 12 and It is attached to both the inner surface (outer diameter surface) of the return portion 14. Further, the inner surface rubber portion 27 is formed as a part of the rubber-like elastic body 21, and thus is integrally formed with the lip portion 22 and the fitting rubber portion 25. Before the mounting, the inner diameter dimension of the return portion 14 and the inner diameter dimension of the fitting rubber portion 25 are set to be equal or substantially equal. Similarly, before mounting, the inner diameter dimension of the return portion 14 and the inner diameter dimension of the fitting rubber portion 25 are set equal to or substantially equal to the outer diameter dimension of the valve stem guide 41, respectively.

  The valve stem seal 1 configured as described above is attached to the valve stem guide 41 as follows.

  That is, first, as shown in FIG. 3A, the outer surface (inner diameter surface) of the return portion 14 of the metal ring 11 of the valve stem seal 1 is exposed without the rubber being attached. The outer surface of the return portion 14 is brought into contact with the tapered portion 44 of the valve stem guide 41 while being kept coaxial with the valve stem guide 41. Next, as shown in FIG. 3 (b), a load (fitting load) is applied to the valve stem seal 1 from one side in the axial direction, the return portion 14 is returned and elastically deformed together with the inner rubber portion 27 (the return portion 14 has its tip). The metal ring 11 is press-fitted into the outer diameter side of the valve stem guide 41 while the fitting rubber portion 25 is compressed and deformed. As shown in FIG. 3C, since the return portion 14 is elastically restored when it reaches the engagement groove 43, it engages with the engagement groove 43 and completes the mounting operation.

  In the valve stem seal 1 having the above configuration, when the metal ring 11 is attached to the valve stem guide 41, the return portion 14 is elastically deformed, so that the metal ring 11 can be easily attached to the valve stem guide 41. The metal ring 11 is unlikely to fall off the valve stem guide 41 because it engages with the engagement groove 43. Further, since a return inner rubber portion 27 is provided between the cylindrical portion 12 and the return portion 14 of the metal ring 11, the return inner rubber portion 27 is elastically deformed together with the return portion 14, and the return portion 14 is elastically deformed. Exhibits a backup action against Therefore, it becomes difficult to cause plastic deformation in the return portion 14. Further, when the return inner rubber portion 27 comes into contact with the inner surface of the engagement groove 43, the space between the cylindrical portion 12 of the metal ring 11 and the valve stem guide 41 can be sealed.

  Further, since the thickness of the return portion 14 is formed to be thinner than the thickness of the cylindrical portion 12, the return portion 14 is easily elastically deformed as it is thin. Therefore, the fitting load when mounting the valve stem seal 1 can be set small, and the mounting workability can be improved. However, the thickness of the return portion 14 is not limited to this, and may be the same thickness as the cylindrical portion 12, for example.

  Further, since the tapered portion 44 is formed from one end surface in the axial direction of the valve stem guide 41 to the outer diameter surface, the return portion 14 extends along the tapered portion 44 when the valve stem seal 1 is attached to the valve stem guide 41. Since it is guided, positioning becomes easy. Therefore, mounting workability can be improved.

  Further, since the return inner rubber part 27 is formed integrally with the lip part 22 and the fitting rubber part 25 as a part of the rubber-like elastic body 21, the lip part 22, the fitting rubber part 25 and the return inner rubber part 27 are formed. Can be molded together with a mold. Therefore, since it is not necessary to set a plurality of sprues or gates in the mold, it is possible to prevent the structure of the mold from becoming complicated even if the inner surface rubber portion 27 is provided on the valve stem seal 1.

  In the above embodiment, the sealing device is the valve stem seal 1 and the metal ring 11 is fitted on the outer diameter side of the valve stem guide 41 which is a guide member. The metal ring 11 may be fitted to the inner diameter side of the member.

  In this embodiment, the return portion 14 is formed by bending the end portion of the cylindrical portion 12 of the metal ring 11 radially outwardly and obliquely at an angle toward one of the axial directions, and the tip of the return portion 14 when mounted. The portion 14a is engaged with an engagement groove 43 provided on the inner diameter surface of the guide member.

  The present invention described above in detail is not limited to the description of the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. For example, in the embodiment, the return portion 14 of the metal ring 11 is annular, but a slit may be provided on the circumference, and a plurality of return portions may be provided side by side on the circumference. Moreover, although the front-end | tip part 14a of the return part 14 is made into the rectangular cross section, it may be chamfered or it may be made into circular arc shape. The angle formed by the bottom surface and the side surface of the engagement groove 43 is approximately 90 degrees, but may be an angle of less than 90 degrees so that the return portion 14 can be more easily engaged.

DESCRIPTION OF SYMBOLS 1 Valve stem seal 11 Metal ring 12 Cylindrical part 13 Flange part 14 Return part 14a Tip part 21 Rubber-like elastic body 22 Lip part 23 Seal lip 24 Back pressure lip 25 Fitting rubber part 26 Garter spring 27 Return inner rubber part 31 Valve stem 41 Valve stem guide 42 Cylindrical portion 43 Engaging groove 44 Tapered portion

Claims (3)

A sealing device that is inserted into a guide member having an engagement groove formed in an outer diameter portion or an inner diameter portion of the cylindrical portion while inserting a shaft member into the inner diameter shaft hole of the cylindrical portion,
A metal ring disposed on the outer diameter side or inner diameter side of the guide member, and a rubber-like elastic body attached to the metal ring,
The rubber-like elastic body is provided with a lip portion that is in sliding contact with the outer diameter portion of the shaft member, and a fitting rubber portion that is press-fitted with a predetermined fitting allowance to the outer diameter portion or the inner diameter portion of the guide member. In the sealing device
A return portion is provided at an end of the metal ring, the return portion engages with the engagement groove, and a return inner rubber portion is provided between the cylindrical portion of the metal ring and the return portion. A sealing device characterized by.   The sealing device according to claim 1, wherein a tapered portion is formed from an end portion of the guide member to an outer diameter portion or an inner diameter portion.   The sealing device according to claim 1, wherein the rubber-like elastic body is integrally formed of the lip portion, the fitting rubber portion, and the return inner surface rubber portion.

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