JP2550548Y2 - Sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a sealing device used as, for example, a radial lip type oil seal, in particular, has a small work load required for mounting, has good holding properties, and The present invention relates to a low-cost sealing device having excellent outer diameter sealing properties.

(Prior Art) As a conventional oil seal, for example, a seal lip is provided on the inner periphery of a metal case having a substantially L-shaped cross section, and the metal case is fitted to a housing. Also, the tenth
Some are shown in the figures (eg, US Pat. No. 4,026,
No. 503). That is, the oil seek 100 includes a metal case 104 which is fluid-tightly fitted to the inner periphery of the shaft hole 102 of the housing 101 via the rubber-like elastic body 103,
And a seal lip 106 made of a rubber-like elastic material, which is integrally fixed by baking and is in sealing contact with the surface of the movable shaft 105.

A convex portion 108 is provided on the rubber-like elastic body 103 on the outer peripheral side so as to protrude outward in the radial direction, and the convex portion 108 is snap-engaged with a groove 107 provided on the inner periphery of the shaft hole 102 of the housing 101 so as to be predetermined. Position was held in position.

(Problems to be Solved by the Invention) However, in the case of the former conventional technique described above, since the metal contacts the housing, the housing or the metal reinforcing ring is damaged when the oil seal is mounted on the housing. May be burned. When such a flaw is large, the sealing performance may be deteriorated. In particular, it is conceivable that the mounting work that is performed several times, such as when the oil seal is replaced, may increase the size of the scratch. It is also conceivable to provide a rubber-like elastic sealing portion on the fitting surface of the oil seal to the housing. However, in the case of a metal reinforcing ring, the fitting force is relatively large, so that when the oil seal is attached, The stress tends to concentrate on the rubber-like elastic seal portion. Therefore, when the stress concentration increases, the sealing portion may be peeled off, and the sealing performance may be deteriorated.

Further, in the case of the latter prior art, the rubber-like elastic body 103
Although it is a snap fit, the groove 1 of the housing 101
Unless 07 is deep, there is a problem that the rubber-like elastic body 103 is soft and cannot provide a sufficient fitting force.

Further, since the outer diameter of the snap fitting portion must be increased in accordance with the groove 107, when the oil seal 100 is incorporated into the housing 101, the outer diameter of the oil seal 100 is larger than the inner diameter of the shaft hole 102 of the housing 101. Since it is large, it is possible that the snap-fitting portion may be damaged. Also,
Since the fitting portion other than the snap fitting portion must be provided with a margin, the fitting force at the time of assembling becomes considerably high, and there is a problem that workability is extremely deteriorated.

On the other hand, oil seals using a plastic case have also been proposed so far, but these are intended to use the same holding mechanism as a conventional oil seal that press-fits in the shaft hole with the oil seal, In this case, a very thick and robust plastic case structure is required for proper holding by press fitting. Particularly under extreme temperature conditions, retention is particularly difficult due to the difference in thermal expansion between metal and plastic.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and the purpose is to reduce the work load required for mounting, have good holding properties, and improve the sealing performance of the outer peripheral portion. It is to provide an excellent sealing device.

(Means for Solving the Problems) In order to achieve the above object, according to the present invention, a metal material housing and a movable shaft which is relatively movably inserted into a shaft hole of the housing are provided. A case that seals the gap and is fluid-tightly fitted to the inner periphery of the shaft hole of the housing, and a seal lip made of a rubber-like elastic material that is integrally baked and fixed to the case and sealingly contacts the surface of the movable shaft. , The case is made of resin, and a protrusion that snap-engages with the housing is provided on the outer peripheral side of the resin case, and is fluid-tightly contacted with the inner periphery of the shaft hole of the housing. A thick seal portion made of a rubber-like elastic material is provided.

The protruding portion may be snap-engaged with a groove provided on the inner periphery of the shaft hole of the housing, or may protrude through the shaft hole and snap-engage with the periphery of the opening of the shaft hole of the housing.

In addition, it is preferable to provide a plurality of slits extending in the axial direction at the end of the resin case in the insertion direction.

In addition, the front end of the resin case in the insertion direction
A radially outwardly extending flange engaging the housing end surface may be provided.

In addition, a rubber-like elastic body that is in fluid-tight contact with the shaft hole inner periphery is adhered and fixed to the fitting surface of the housing made of the resin case on the outer periphery of the shaft hole, and this rubber-like elastic material may be used as a seal ring. It is effective.

(Operation) In the sealing device having the above configuration, when the resin case is inserted into the inner periphery of the shaft hole of the housing, the inclined surface of the introduction portion provided on the distal end side of the protrusion in the insertion direction is formed on the periphery of the opening of the housing. The contact portion urges the protrusion in the diameter reducing direction, so that the insertion operation can be easily performed. Then, the protruding portion passes through a groove or a shaft hole on the inner periphery of the shaft hole of the housing, snap-engages with the periphery of the opening, and is fitted and fixed to the housing. Since the case is made of resin as described above, the case is rigid as compared with the conventional case where the rubber-like elastic body is snap-fitted, and the outer diameter of the protrusion to be snap-fitted does not need to be large. Since it is not hard, the fitting force when assembling does not increase.

Further, if a slit is provided in the resin case, the stress on the resin case during mounting can be reduced, and the margin of fitting of the protruding portion to the shaft hole can be increased.

Further, if a flange is provided at the end of the resin case on the front side in the insertion direction, the flange can be engaged with the end face of the housing to ensure the positioning.

Further, by attaching a rubber-like elastic body or attaching a seal ring to the outer periphery of the resin case, the sealing performance of the outer peripheral fitting portion with the shaft hole can be further improved.

(Example) Hereinafter, the present invention will be described based on an illustrated example.
In FIGS. 1 and 2 showing a sealing device according to an embodiment of the present invention, reference numeral 10 denotes an entire oil seal as a sealing device. As in the conventional example, a housing 11 and a shaft hole of the housing 11 are provided. Rotary shaft inserted into 12 so as to be relatively movable
It is designed to seal the gap between it and 13.

When the oil seal 10 is designed, a seal lip 1 made of a rubber-like elastic body which is urged by a spring 6 so as to make a dynamic contact with the rotating shaft 13 is employed in order to perform a main sealing action. For this technical field, there is no difference from the design of the oil seal 10 of a general radial lip, and since it is not the main point of the present invention, various lip shapes can be applied.

The present invention comprises a means for fixing the sealing device 10 to the housing 11 and preventing leakage of a sealing fluid such as oil through the outer peripheral fitting portion of the plastic case 2 made of a plastic material as a resin. Have been.

The plastic case 2 is formed of, for example, a polyamide (nylon) material filled with glass fiber.
A cylindrical portion 21 having a substantially L-shaped cross section and fitted into the shaft hole 12
And an inward flange portion 22 extending radially inward from one end of the cylindrical portion 21.

First, the seal lip 1 is chemically fixed to the inner end of the inward flange portion 22 as the first portion, and the tip of the seal lip 1 slidably contacts the surface of the rotating shaft 13. Leakage of sealed fluid such as oil is prevented.

Further, the cylindrical portion 21 as the second portion extends in the axial direction near the housing 11 forming an annular cylinder. At the end opposite to the inward flange portion 22 extending inward, an annular protrusion which interferes with the inner periphery of the shaft hole 12 of the housing 11 and snap-fits into the groove 14 on the inner periphery of the shaft hole 12 of the housing 11. The part 3 is formed.

The plastic case 2 has a series of slits 4 as shown in FIG. 3 to form a plurality of cantilevered projections in place of a single perfectly cylindrical annular projection 3. It can also be provided and molded. By providing the slits 4 and providing the cantilevered projections 3 'in this manner, the work load required for mounting is reduced, and the completely cylindrical projections 3 interfere with the plastic case 2 considerably. In order to reduce the stress that occurs.

The shape of the projection 3 has a partially angled lead-in portion 31 so that during mounting in the shaft hole 12 of the interfering housing 11 the first point of contact with the housing 11 is oil The annular projection 3 or the cantilevered projection 3 'is elastically deformed inward so that the seal 10 can be easily mounted.

When the projections 3, 3 'reach the groove 14 in the housing 10 during the mounting operation, the oil seal 10
Is fixed in this position. In order to hold the oil seal 10 as much as possible, the groove 14 of the housing 11 is square or rectangular with sharp corners, and the return angle of the projections 3, 3 'is I have to do it. In some circumstances, if it is necessary to remove or replace the oil seal, the return angle on the projections 3, 3 'and the return angle of the groove 14 in the housing 11 will be the required removal angle with respect to the shaft hole 12. , And House 11
The angle of the groove 14 can be varied to define a range of mounting and removal forces that all meet the needs of a wide range of sealing situations.

The shape of the plastic case 2 is not limited to an L-shaped cross section. For example, as shown in FIG. 4, the cylindrical portion 21 is bent into a U-shape at the tip end side in the insertion direction into the shaft hole 12. The inner cylinder 211 and the outer cylinder 212 may have a double structure. The plastic case 2 has an inward flange portion 22 extending from one end of the inner cylindrical portion 222, and further has an outward flange 213 that engages with the end surface of the housing 11 at the front edge in the insertion direction of the plastic case 2. I have.

Further, as means for performing an appropriate seal between the plastic case 2 and the housing 11, a rubber-like elastic body 5 bonded to the outside of the plastic case 2 so that the rubber-like elastic body 5 interferes with the housing 11 is provided. As a result, a seal between the plastic case 2 and the housing 11 becomes possible. In this sealing portion, the inner peripheral surface of the shaft hole 12 of the housing 11 is
The projection 3 is a sliding surface that slides when it reaches the groove 14. However, since the projection 3 is not made of a metal material, no scratch occurs and the rubber-like elastic body 5 is stably contacted. At the same time, good sealing properties are maintained. The rubber-like elastic body 5 is molded from the same material as the inner seal lip 1 formed by a molding operation so as to be effective.

The rubber-like elastic body 5 can also be molded into a shield outside the plastic case 2 or, as shown in FIG. 6, to completely or almost completely surround the plastic case 2. Further, as shown in FIG. 5, a squeeze packing 7 such as a rubber-made elastic D-ring may be attached to the outer periphery of the cylindrical portion of the plastic case 2. Various variations are taken to surround the plastic case 2 with the rubber-like elastic body 5 merely to simplify the molding method of the rubber-like elastic body 5, and the rubber which is the main point of the new design is used. It does not change the basic snap fit of the case 2 with the static seal design of the elastic body 5.

In addition, although another structure is used, another form of the present invention using the same outer diameter fixing method and the same sealing mechanism, as shown in FIG. 7 to FIG. Is a case where no special groove is provided and a direct housing 11 is used instead. The projecting portions 3, 3 'of the plastic case 2 are snap-fitted to the front end of the housing in the direction of insertion of the oil seal 10, in this embodiment, the opening edge on the sealed fluid side. To prevent being mounted too far apart,
An outward flange 213 corresponding to the outer surface of the housing 11 is used.

Other configurations and operations are the same as those of the above-described embodiment. Therefore, the same components will be denoted by the same reference numerals and description thereof will be omitted.

(Effects of the Invention) The present invention has the above configuration and operation, and includes a resin case, and in order to compensate for a decrease in fitting force due to the resin case, the case has a protrusion. Is provided and snap-engaged with the metal material housing, the engagement force between the case and the housing can be improved. In addition, the sealing property between the housing and the case is improved by the rubber-like elastic material sealing portion provided on the outer periphery of the case. Further, a change in fitting force due to a difference in the coefficient of thermal expansion between the housing and the case due to a temperature change can be prevented by the elasticity of the resin case and the seal portion.

In addition, since the portion of the case that comes into contact with the housing at the time of mounting is made of resin, the housing is not damaged.
Therefore, the seal made by the rubber-like elastic material seal portion is kept constant. Further, even if the oil seal is replaced several times, the sealing property is kept constant.

In addition, when the case is provided with an axial slit, the moldability can be further improved by further improving the mounting property and improving the flow of the rubber material on the inner and outer circumferences of the case during molding.

Further, by providing a flange that engages with the housing end face, the positioning accuracy in the axial direction and the engagement force can be stabilized.

And, the cost is lower than the seal provided with the metal case, has a good holding performance, and by providing the rubber-like elastic body on the outside, the good sealing performance of the outer peripheral fitting portion with the shaft hole of the case is improved. Can also be secured.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an essential part of a state after a sealing device according to an embodiment of the present invention is mounted, FIG. 2 is a sectional view of an essential part of an oil seal having a cylindrical projection, and FIG. FIG. 4 is a cross-sectional view of a main part of a sealing device having a holding protrusion, FIG.
The figure is a cross-sectional view of the main part of a state after the mounting of another type of sealing device provided with a D-ring, and FIG. 6 is a sealing device using a cantilever-like projection, and a rubber-like elastic body excluding the projection. FIG. 7 is a sectional view of an essential part of another type of sealing device having an enclosed plastic case, FIG. 7 is a sectional view of an essential part of another type of sealing device having a through-type housing, and FIG. FIG. 9 is a cross-sectional view of a principal part of another type of sealing device used with the annular protrusion. FIG. 9 is a cross-sectional view of a main part of another type of sealing device used with the direct-type housing and the cantilevered protrusion. It is principal part sectional drawing of the mounting state of the conventional sealing device. DESCRIPTION OF SYMBOLS 1 ... Seal lip 2 ... Plastic case 21 ... Cylinder part 22 ... Inward flange part 211 ... Inner cylinder part 212 ... Outer cylinder part 213 ... Outward flange part 3,3 'Projecting part, 31 Introduction part 4 Slit 5 Rubber elastic body, 6 Spring 10 Oil seal, 11 Housing 12 Shaft hole, 13 Rotating shaft 14 …groove

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-12178 (JP, A) JP-A 2-114262 (JP, U) JP-A 62-194250 (JP, U) JP-A 59- 127963 (JP, U) Japanese Utility Model Showa 63-166673 (JP, U) Japanese Utility Model Showa 52-56151 (JP, U) Japanese Utility Model Showa 61-198770 (JP, U)

Claims (5)

(57) [Scope of request for utility model registration] 1. A seal for sealing a gap between a metal material housing and a movable shaft inserted into a shaft hole of the housing so as to be relatively movable. The housing is fluid-tightly fitted to an inner periphery of the shaft hole. A sealing case made of a rubber-like elastic material, which is integrally fixed to the case by baking and fixed and comes into sealing contact with the surface of the movable shaft, wherein the case is made of resin, The outer peripheral side of the housing is integrally provided with a resin protrusion that snap-engages with the housing, and a thick seal portion made of a rubber-like elastic material that is in fluid-tight contact with the inner periphery of the shaft hole of the housing. Sealing device characterized by being carried out. 2. The sealing device according to claim 1, wherein the projecting portion is adapted to snap-fit into a groove provided on the inner periphery of the shaft hole of the housing. 3. The sealing device according to claim 1, wherein the projecting portion passes through the shaft hole of the housing and snap-engages with the housing around the periphery of the shaft hole opening. 4. The sealing device according to claim 1, wherein a plurality of slits extending in the axial direction are provided at an end of the resin case at the front end side in the insertion direction. 5. The resin case according to claim 1, further comprising a radially outwardly extending flange which engages with the housing end surface at a front end in the insertion direction of the resin case. A sealing device according to any one of the preceding claims.