JPH0514051Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an oil seal used between two members that are assembled concentrically with each other to perform relative rotational motion. The present invention relates to an oil seal that is a combination of a wear sleeve having a cross-sectional shape and a seal member having a seal lip made of a rubber-like elastic material that seals and slides on the cylindrical circumferential surface of the wear sleeve.

(Prior Art) As illustrated in FIG. 5, a wear sleeve having a substantially L-shaped cross section is attached to a rotating shaft, and a sealing member having a sealing lip made of a rubber-like elastic material is attached to a housing. An oil seal is known which is attached to the side of the wear sleeve and has a seal lip made of a rubber-like elastic material in sealing contact with the circumferential surface of the wear sleeve.

The oil seal shown in the figure includes a cylindrical portion 3 whose inner circumferential side is coated with a rubber-like elastic material, and
a wear sleeve 2 attached to the rotating shaft 1 and having a flange portion 4 extending in the radial direction from one end;
It has a held part 7 made of an annular body having a substantially F-shaped cross-sectional shape and a seal lip 8 made of a rubber-like elastic material and bonded to the inner end of the held part 7. A sealing member 6 has a holding part 7 attached to the housing 5 and sealingly slides a seal lip 8 onto the circumferential surface of the cylindrical part 3 of the wear sleeve 2. The unitizing plate 10 is connected to the end portion 14 and faces the flange portion 4 of the wear sleeve 2.

The above-mentioned oil seal connects the flange portion 4 of the wear sleeve 2 attached to the rotating shaft 1 to the protrusion attached to the side surface of the flange portion 4 of the held portion 7 of the seal member 6 in the axial direction of the held portion 7. Atmospheric side end 1
sandwiched between unitized plates 10 connected to 4,
The relative position of the wear sleeve 2 and the seal member 6 in the axial direction is restricted, and the labyrinth effect caused by the small gap formed between the flange portion 4 and the unitizing plate 10 and the auxiliary lip provided adjacent to the main lip It is constructed to prevent dust, muddy water, etc. from entering from the outside, and to prevent internal lubricant from leaking due to the main lip disposed inward.

(Problem to be solved by the invention) In order to ensure the intrusion prevention function against external dust etc. in the oil seal described above, the gap between the flange portion 4 and the unitizing plate 10 is set as narrow as possible to create a labyrinth effect due to the gap. Although it is effective to strengthen the gap, if the gap is set to an extremely small value, not only will it be difficult to regulate the relative position in the axial direction between the wear sleeve 2 and the seal member 6, but also the There is a strong possibility that friction loss will increase due to mutual contact between the two.

There are also examples in which at least a single dust strip is provided on the side surface of the flange portion 4 or the unitizing plate 10 so as to slide in a sealing manner against the opposing surface, but this is also preferable since the friction loss between the two members 2 and 10 increases. do not have.

On the other hand, the flange portion 4 of the wear sleeve 2 extends radially outward from the cylindrical portion 3, and the unitizing plate 10, which is coupled to the held portion 7 of the seal member 6 and faces the flange portion 4, extends radially inward. Because of this structure, external dust or muddy water can reach the seal lip 8 side through the small gap between the flange portion 4 and the unitizing plate 10 due to the centrifugal force generated as the wear sleeve 2 rotates. There remains a risk that this will happen.

The purpose of this invention is to provide an oil seal structure which overcomes the problems of the conventional oil seals described above, minimizing friction loss caused by rotation, and preventing the intrusion of external dust and other particles due to centrifugal force.

(Means for Solving the Problems) In consideration of the problems with the oil seals according to the prior art described above, the present invention is designed to extend in the radial direction from a cylindrical part attached to a rotating shaft and form a substantially L-shape together with the cylindrical part. A flange part constituting a wear sleeve having a cross-sectional shape, a held part having a substantially F-shaped cross-sectional shape and attached to the housing, and a part attached to the inner end of the held part and attached to the periphery of the cylindrical part of the wear sleeve. The wear sleeve is attached to at least one opposing surface of the unitizing plate, which is connected to the end of the held portion of the seal member and has a seal lip made of a rubber-like elastic material that sealsly slides on the surface of the unitizing plate, which faces the flange portion of the wear sleeve. A helical protrusion or groove is provided that provides a hydrodynamic pumping action that moves the fluid present in the gap between the flange portion and the unitizing plate radially inward as the unitizing plate rotates. A drain hole is formed at a position opposite to the outer end of the flange portion.

If the spiral protrusion or groove is provided on the flange of the wear sleeve or on the facing surface of the unitizing plate and provides a hydrodynamic pumping action during rotation, the spiral protrusion or groove is provided on the flange of the wear sleeve, in the direction of rotation. If provided on the unitizing plate side, it is formed so as to gradually approach the center from the outside along the rotation direction.

(Function) In the oil seal having the above configuration, the spiral protrusion or groove formed on the facing surface of at least one of the flange portion of the wear sleeve and the unitizing plate is exposed from the outside as the wear sleeve rotates. It exhibits an inward hydrodynamic pumping action, moving dust and muddy water existing in the gap between the flange part and the unitizing plate from the outside in the radial direction to the inside against the centrifugal force caused by rotation. This prevents the lubricant from entering the internal lubricant side, and the axially sealed side of the flange portion 4 is a sealed space, and a lubricant is provided on either one of the facing surfaces between the flange portion 4 and the unitizing plate 10. Providing only the spiral protrusions or grooves 11 is difficult to produce a hydrodynamic pumping action since there is no air inlet for producing a hydrodynamic flow. Therefore, by providing the drain hole 13 at a position facing the outer end of the flange portion 4 of the unitizing plate 10, the drain hole 13
Since a flow is formed from the seal to the outside of the seal through the gap between the flange portion 4 and the unitizing plate 10, the radially inward flow due to the hydrodynamic pumping action can be further promoted. However, even under the hydrodynamic pump action, muddy water moving in the outer radial direction cannot be completely eliminated due to centrifugal force that opposes the pump action. Therefore, the muddy water that has moved in the direction of the outer diameter is removed by the drain hole.

(Embodiment) In the embodiment shown in FIG. 1, a wear sleeve 2 has a cylindrical portion 3 and a flange portion 4 extending radially from the cylindrical portion 3, and has a substantially L-shaped cross-sectional shape.
However, the cylindrical portion 3 is attached to the rotating shaft 1, and the sealing member 6 is formed by adhering a seal lip 8 made of a rubber-like elastic material to the inner end of the held portion 7, which has a substantially F-shaped cross-sectional shape. A seal lip 8 is attached to the housing 5 to bring it into sealing contact with the circumferential surface of the cylindrical portion 3 of the wear sleeve 2, and a seal lip 8 is attached to the end of the held portion 7 so as to face the flange portion 4 of the wear sleeve 2. A unitizing plate 10 having a substantially snake-eye shape is combined, and a coating made of a rubber-like elastic material is applied to the surface of the flange portion 4 facing the unitizing plate 10. Details of the coating are shown in the perspective view and in FIG. As shown in the front view of FIG. 3, a substantially spiral groove 11 is provided that gradually moves outward from the center side along the direction of rotation indicated by an arrow.

The annular projection 12 attached to the outer end of the flange portion 4 of the wear sleeve 2 and the annular groove formed by the annular projection 12 are spirally shaped by centrifugal force that resists the hydrodynamic pumping action of the helical groove 11. The drain hole 13 provided at the outer end of the unitizing plate 10 provides an auxiliary function of preventing muddy water, etc. that has reached the outside beyond the groove 11 from entering the inner seal lip 8 side. This is to remove muddy water, etc. that has moved radially outward due to centrifugal force. Further, the axially sealed side of the flange portion 4 is a sealed space, and it is not enough to simply provide a spiral protrusion or groove 11 on either one of the facing surfaces between the flange portion 4 and the unitizing plate 10. , there is no air inlet to create a hydrodynamic flow, making it difficult to create a hydrodynamic pumping action. Therefore, by providing a drain hole 13 at a position facing the outer end of the flange portion 4 of the unitizing plate 10,
Since a flow is formed from the drain hole 13 to the outside of the seal through the gap between the flange portion 4 and the unitizing plate 10, it also shows the function of promoting the hydrodynamic pumping action of the spiral groove 11. be.

In the other embodiment shown in FIG. 4, in addition to the spiral groove 11 provided in the flange portion 4 of the wear sleeve 2,
A spiral groove is provided on the opposing surface of the unitizing plate 10,
Furthermore, a drain hole 13 for discharging muddy water, etc. is provided at the lower end of the unitizing plate 10, so that natural outflow of muddy water, etc. is expected.

(Effects of the Invention) As described above, the oil seal of the present invention has a diameter of 100 mm on at least one of the opposing surfaces of the unitizing plate connected to the flange portion of the wear sleeve and the end of the held portion of the seal member during rotational operation. By having a helical protrusion or grooved configuration that provides a hydrodynamic pumping action in the radial inward direction, the muddy water that exists between the flange section and the unitizing plate is directed in the radial inward direction. The force is applied to eliminate the influence of centrifugal force generated with rotational operation, but the axially sealed side of the flange part is a sealed space, and either one of the opposing surfaces between the flange part and the unitizing plate Merely providing a spiral protrusion or groove provided in the groove is difficult to produce a hydrodynamic pumping action since there is no air inlet for producing a hydrodynamic flow. Therefore, by providing a drain hole at a position facing the outer end of the flange part of the unitizing plate, a flow is formed from the drain hole to the outside of the seal through the gap between the flange part and the unitizing plate, so that it flows radially inward. Facilitate the formation of a countercurrent. However, even under the hydrodynamic pump action, muddy water moving in the outer radial direction cannot be completely eliminated due to centrifugal force that opposes the pump action. Therefore, since this muddy water that has moved in the direction of the outer diameter is removed by the drain hole, damage to the seal lip due to muddy water etc. entering the inside can be effectively prevented.

In the above explanation, the wear sleeve side rotates and the sealing member side is kept stationary, but the present invention is effective even when the wear sleeve side is kept stationary and the sealing member side rotates. Applicable.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an embodiment of the present invention, Fig. 2 is a perspective view of the main parts of the embodiment, Fig. 3 is a front view of the main parts, and Fig. 4 is a cross-sectional view of the main parts of the embodiment. FIG. 5 is a partial cross-sectional view of a main part of another embodiment, and FIG. 5 is a cross-sectional view of an example of an oil seal according to the prior art. 1... Rotating shaft, 2... Wear sleeve, 3...
Cylindrical part, 4... Flange part, 5... Housing,
6... Seal member, 7... Holding portion, 8... Seal lip, 10... Unitizing plate, 11... Spiral groove, 12... Annular projection, 13... Drain hole.

Claims (1)

[Scope of utility model registration request] A wear sleeve 2 having a substantially L-shaped cross section and having a cylindrical portion 3 and a radially extending flange portion 4 attached to the rotating shaft 1, a held portion 7 having a substantially F-shaped cross-sectional shape, and a rubber sleeve. It has a seal lip 8 made of an elastic material and adhered to the held part 7, and the held part 7 is attached to the housing 5 so that the seal lip 8 slides on the circumferential surface of the cylindrical part 3 in a sealed manner. It has a sealing member 6, and a unitizing plate 10 which has a substantially snake-eye shape and is coupled to an end of the held part 7 and faces the flange part 4,
The wear sleeve 2 is attached to at least one of the opposing surfaces of the flange portion 4 and the unitizing plate 10.
is provided with a spiral protrusion or groove 11 formed in a direction that provides a hydrodynamic pumping action that moves the fluid between the flange portion 4 and the unitizing plate 10 radially inward as the unit rotates. At the same time, the flange portion 4 of the unitizing plate 10
An oil seal having a drain hole 13 at a position opposite to the outer end of the oil seal.