JP2003194078A - Sealing device for rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device for a rolling bearing capable of securely preventing the intrusion of water into a housing such as a hub and capable of maintaining the bearing performance for a long time without lowering strength of an outer ring and without increasing the number of part items. <P>SOLUTION: This sealing device for a rolling bearing is provided with a seal 35, of which peripheral part is installed in the outer ring 32, and an annular cover plate 5, which is fixed to the housing (hub) 2 and of which inner peripheral part is extended to an inner ring 31 through the outside of the seal 35. The seal 35 is provided with a main lip 35c to be slid to be brought in contact with the outer peripheral surface of the inner ring 31 and a side lip 35d projected outside of the bearing to be brought in contact with a cover plate side surface. Intrusion of the water from the inner peripheral side of the cover plate 5 into the hub 2 through the outside of the rolling bearing 3 can be securely prevented in a contact part between the side lip 35d with the cover plate 5. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing sealing device, and more particularly to a rolling bearing sealing device suitable for use in a semi-floating axle. 2. Description of the Related Art Semi-floating axles are frequently used as rear axles for small 4WD vehicles. In a semi-floating axle, the axle tube receives part of the axle load,
The axle receives the reaction force from the tire side, and the rotation of the axle is supported by rolling bearings provided in the hub. An example of the structure is shown in FIG. In the example shown in FIG. 3, an axle 11 on which a wheel is mounted passes through an axle tube 12 and is rotatably supported via a rolling bearing 13 provided in the axle tube 12. The axle tube 12 is attached to a chassis via a leaf spring or the like, and a brake rotor or the like is attached to a flange portion 12a formed at a tip portion thereof. [0004] The rolling bearing 13 includes an inner ring 131 and an outer ring 13.
2, a plurality of rolling elements 133 arranged between them, a cage 1 for holding each rolling element 133 at a constant pitch in the circumferential direction.
34, and a seal 135 for sealing an axial end of an annular space formed between the inner race 131 and the outer race 132. In this example, the seal 135 is an outer end, that is, an end exposed from the axle tube 12. The inner end is open and the inner end is sealed by an axle seal 14 inserted between the axle tube 12 and the axle 11. . The above-described rolling bearing 13 has an inner race 131
Is fitted and fixed to the outer peripheral surface of the axle 11, and the outer ring 132 is fitted to the inner peripheral surface of the axle tube 12. In such a method of using the rolling bearing 13 for rotation of the inner ring, the fitting between the inner ring 131 and the axle 11 is a tight fit, while the outer ring 1 is fitted.
The fit between the shaft 32 and the axle tube 12 is an intermediate fit or a clearance fit. In order to prevent the outer ring 132 from coming out of the axle tube 12 and to prevent foreign substances such as muddy water and sand from entering the axle tube 12, the axle tube 12 has a cover plate 15 made of an annular plate member. Is attached. This cover plate 15
Is fixed to the flange portion 12a of the axle tube 12,
The inner peripheral side passes through the outer ring 132 of the rolling bearing 13 to the inner ring 131 side, extends to the vicinity of the axle 11, and
At the same time as restricting the movement of the shaft 32 outward in the axial direction, it also functions as a cover for foreign substances such as muddy water and sand. Since the cover plate 15 is a press-formed product, its flatness is relatively rough, and in order to fill a gap between the axle tube 12 and the flange portion 12a to obtain watertightness between them. A resin adhesive is applied between the two. In the conventional axle structure as described above, watertightness is obtained by interposing an adhesive between the flange portion 12a of the axle tube 12 and the cover plate 15, and rolling is performed by the seal 135. Even if water tightness between the inner ring 131 and the outer ring 132 of the bearing 13 is obtained, it may not be possible to reliably prevent the water that has entered in the direction indicated by the arrow in FIG. . That is, the cover plate 15 and the outer ring 13
There is a slight gap between the outer ring 132 and the outer ring 132 and the axle tube 12. The fitting between the outer ring 132 and the axle tube 12 is an intermediate fitting or a clearance fitting as described above. Therefore, the water entering in the direction shown by the arrow in FIG.
2 and between the inner peripheral surface of the axle tube 12 and the outer peripheral surface of the outer ring 132, and may penetrate into the axle tube 12, thereby causing rust on the rolling bearing 13. This may affect the bearing life. Here, in order to prevent water from entering through such a path, conventionally, the outer peripheral surface of the outer race 132 and the axle tube 12
The O-ring is interposed between the inner peripheral surfaces of the seals 135, or the elastic body is protruded linearly (cylindrically) outwardly in the axial direction from the metal core of the seal 135 to make contact with the cover plate 15 (in either case). Japanese Patent Application Laid-Open No. 2000-2253) is employed. [0011] Among the above-mentioned prior arts, the one in which an O-ring is interposed between the outer peripheral surface of the outer ring and the inner peripheral surface of the axle tube is described in the prior art. O on the surface
-It is necessary to form a groove for holding the ring, and the strength of the outer ring is unfavorably reduced for a semi-floating axle in which a moment load acts on the axle. In the structure in which the elastic body projects cylindrically outward from the core of the seal in the axial direction and abuts on the cover plate, the elastic body simply projecting in a cylindrical shape is perpendicular to the surface of the cover plate. Although contact pressure is obtained by contact and elastic deformation, it is difficult to obtain sufficient contact pressure over the entire circumference because the flatness of the cover plate is relatively rough as described above. There is a problem that it is difficult to obtain reliable sealing performance. The present invention has been made in view of such circumstances, and ensures that water does not enter a housing such as an axle tube without reducing the strength of an outer ring and without increasing the number of parts. It is an object of the present invention to provide a sealing device for a rolling bearing which can prevent the occurrence of the above problem and maintain the bearing performance for a long period of time. [0014] To achieve the above object, a sealing device for a rolling bearing according to the present invention is a sealing device for sealing an axial end of a rolling bearing, comprising: An elastic material for forming a lip is integrally formed on the core metal, and an outer peripheral portion thereof is fixed to a seal mounted on the outer ring and a housing for accommodating the rolling bearing, and an inner peripheral portion is formed outside the seal. The seal has a main lip slidably in contact with the outer peripheral surface of the inner ring, and the seal lip projects toward the outside of the bearing so as to have a gradually decreasing diameter. Characterized by having a side lip that contacts the lip. According to the present invention, in addition to the main lip slidingly contacting the outer peripheral surface of the inner ring, the seal attached to the outer ring of the rolling bearing contacts the side surface of the cover plate disposed outside the seal. An intended purpose is achieved by forming a side lip so as to project and making the direction of the projection of the side lip gradually smaller toward the outside of the bearing. That is, the side lip in the present invention has a direction in which the diameter gradually decreases toward the outside of the bearing. It is a direction against the flow of water to be tried, and can prevent the intrusion even if a large water pressure is applied from the outside. The side lip is formed integrally with the seal mounted on the rolling bearing and comes into contact with the cover plate, so that the number of parts increases and a groove is formed on the outer peripheral surface of the outer ring to reduce its strength. And because it is in contact with the cover plate in an oblique direction, the amount of deformation required to generate the contact pressure can be increased, and even if the flatness of the cover plate is rough, An effective contact pressure can be obtained over the circumference. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an axially parallel sectional view of an embodiment in which the present invention is applied to a semi-floating type rolling bearing for a rear axle, and FIG. 2 is an enlarged view of a main part thereof. The basic configuration in this example is the same as that shown in FIG. 3, and an axle 1 on which a wheel is mounted passes through an axle tube 2 and a rolling bearing 3 provided in the axle tube 2. It is rotatably supported via. Rolling bearing 3
Are formed between the inner ring 31 and the outer ring 32, a plurality of rolling elements 33 disposed between them, a retainer 34 for holding the rolling elements 33 at a constant pitch in the circumferential direction, and the inner ring 31 and the outer ring 32. In order to seal the end of the annular space on the side exposed from the axle tube 2, it is constituted by a seal 35 attached to one end. The other end of the rolling bearing 3 is open as in the example of FIG. 3, and the inner end is sealed by a shaft seal 4 equivalent to that of FIG. I have. An outer ring 32 is provided on the flange portion 2a of the axle tube 2.
And a cover plate 5 for preventing foreign substances such as mud and sand from penetrating into the axle tube 2. The cover plate 5 is made of an annular plate-like member similar to the conventional one, and is fixed to the flange portion 2a of the axle tube 2 by the bolt 2b, and at the same time, a resin adhesive is interposed between them. Is applied to obtain watertightness between the two. This cover plate 5 has an outer ring 32 and a seal 35 near its inner peripheral portion.
And reaches the inner ring 31 side through the outside. The cover plate 5 and the outer end surface of the outer ring 32 are lightly in contact with each other, and the cover plate 5 is formed with an outward bent portion 5a on the inner peripheral side of the contact portion with the end surface of the outer ring 32, and the bent portion is formed. The inner peripheral side of 5a is a straight portion 5b extending parallel to the bearing end face via a predetermined gap with respect to the seal 35. The seal 35 of the rolling bearing 3 has a core metal 35a.
And an annular material made of an elastic material 35b such as rubber molded integrally with the core metal 35a. The inner edge portion is made of an elastic material and slides on the outer peripheral surface (shoulder portion) of the inner ring 31. A contacting main lip 35c is provided, and a side lip 35d also made of an elastic material is provided on a side surface facing the outside of the rolling bearing 3. The seal 3 is mounted on the rolling bearing 3 by fitting its outer edge into a seal groove 32 a formed in the inner peripheral surface of the outer ring 32. The side lip 35d protrudes toward the outside of the rolling bearing 3 so as to gradually become smaller in diameter, and its tip portion is in contact with the inner surface of the straight portion 5b of the cover plate 5. According to the above-described embodiment of the present invention, the side lip 35d protruding toward the outside of the rolling bearing 3 in the direction of gradually decreasing the diameter is in contact with the inner surface of the cover plate 5, so that the side lip 35d The direction of projection of the lip 35d from the base end side to the tip end side is directed to the bearing side through the space between the inner peripheral surface of the cover plate 5 and the outer peripheral surface of the axle 1, as indicated by an arrow in FIG. The direction is opposite to the flow of water. Therefore, even if the pressure or the flow velocity of the water to be penetrated increases, it is possible to reliably prevent the water from entering between the side lip 35 d and the cover plate 5. Further, since the side lip 35b abuts obliquely on the cover plate 5, the amount of deformation of the side lip 35 for generating an abutting pressure therebetween can be increased, and the cover plate 5 Even if the flatness is rough, an effective contact pressure for obtaining watertightness over the entire circumference can be obtained. As a result, the cover plate 5 and the outer ring 32
Even if there is a gap between the inner surface of the axle tube 2 and the outer surface of the outer ring 32, the outer ring 32 is fitted to the axle tube 2 by intermediate fitting or clearance fitting. Even if there is a gap, it is possible to reliably prevent water from entering the axle tube 2. As described above, according to the present invention, the annular seal attached to the outer ring and the annular cover extending from the outer peripheral side of the outer ring to the inner ring side through the outer ring and the side of the seal. In addition to the plate, the seal has a main lip that slides into contact with the outer peripheral surface of the inner ring and a side lip that projects so that the diameter gradually decreases toward the outside of the bearing. Because of the contact, the water that is going to enter the housing through the inner peripheral side of the cover plate projects from the base end to the front end in a direction against the flow of the water and contacts the cover plate. The side lip can reliably prevent the intrusion. Further, since the side lip abuts against the cover plate at an angle, the amount of deformation of the side lip for generating the abutting pressure of the side lip against the cover plate can be increased, so that the flatness of the cover plate is rough. However, it is possible to obtain an effective contact pressure for obtaining water tightness over the entire circumference. Therefore, by applying the present invention to, for example, a semi-floating axle, it is possible to reliably prevent water from entering the hub, and to prevent a reduction in service life and a reduction in performance due to generation of rust in the rolling bearing. can do. In addition, according to the present invention, since no other member for sealing is required other than the cover plate and the seal, the cost does not increase due to an increase in the number of parts, and a groove or the like is formed on the outer periphery of the outer ring. Since there is no need to perform this, there is no problem that the strength of the outer ring is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an axially parallel sectional view of an embodiment in which the present invention is applied to a semi-floating type rolling bearing for a rear axle. FIG. 2 is an enlarged view of a main part of FIG. FIG. 3 is a cross-sectional view showing a structural example of a conventional semi-floating rear axle. [Description of Signs] 1 axle 2 axle tube 2a flange portion 3 rolling bearing 31 inner ring 32 outer ring 33 rolling element 34 retainer 35 seal 35a core metal 35b elastic material 35c main lip 35d side lip 4 shaft seal 5 cover plate

Claims (1)

Claims 1. A sealing device for sealing an axial end of a rolling bearing, wherein an elastic material for forming a lip is integrally formed with an annular core, The outer peripheral portion is fixed to a seal that is mounted on the outer ring and a housing that accommodates the rolling bearing,
The inner peripheral portion has an annular cover plate extending to the inner ring side through the outside of the seal, and the seal has a main lip slidingly contacting the outer peripheral surface of the inner ring and a gradually decreasing diameter toward the outside of the bearing. A sealing device for a rolling bearing, characterized in that the sealing device has a side lip protruding so as to come into contact with the side surface of the cover plate.