JPH10196664A - Sealing device for rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a lubrication oil film for a long time by forming multiple projection parts with specific height in the circumference direction of a sliding contact face of a seal lip at random or in the predetermined arrangement and covering the slide contact face including the projection parts by means of a lubrication film made of a low friction material. SOLUTION: On a sliding contact face 4a with a shoulder part slanting face of an inner ring of a seal lip 4, two lines of projection parts 7, 8 are arranged in numbers evenly in the circumference direction. In addition, the sliding contact face 4a including the projection parts 7, 8 is covered with a lubrication film 9 made of a low friction polytetrafluoroethylene material. The height (h) of the projection parts 7, 8 is set to be 5-50μm. As a result, in the projection parts 7, 8 on the sliding contact face 4a of the seal lip 4, a face pressure of the part facing the bearing rotation direction is increased as against that of the part facing the reverse rotation direction, so that friction gaps are generated in the projection parts 7, 8. As a result, a clearance between respective parts, that is, surface roughness can be maintained for a long time, and a lubricating oil sump based on the surface roughness can be secured for a long time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing sealing device.

[0002]

2. Description of the Related Art Conventionally, in a rolling bearing sealing device in which a seal lip of a seal ring fixed to one race is slid on a shoulder of the other race, a sliding contact surface of the seal lip is provided. Has an appropriate roughness, for example, 1 μm to 10 μm Rz, to form a lubricating oil film. When a bearing is used, the roughness decreases as the sliding surface of the seal lip wears, and it may be difficult to maintain a lubricating oil film.

[0003]

When a bearing is used, the roughness of the sliding contact surface of the seal lip may decrease with wear of the sliding contact surface, and it may be difficult to maintain a lubricating oil film.

Accordingly, an object of the present invention is to provide a sealing device for a rolling bearing which can maintain the surface roughness of a sliding contact surface of a seal lip of a seal ring for a long time and can secure a lubricating oil film for a long time. It is.

[0005]

Means for Solving the Problems As means for solving the above-mentioned problems, a seal lip of a seal ring fixed to one race is slidably contacted with a shoulder of the other race. In the sealing device, a number of projections having a height of 5 μm to 50 μm are formed in a random or predetermined arrangement in a circumferential direction of the sliding contact surface of the seal lip, and the sliding contact surface including the projections has low friction. It is characterized by being coated with a lubricating film made of a material.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 relates to a sealing device for a ball bearing, in which a seal lip 4 of a seal ring 3 fixed to a peripheral groove 1 a at an inner peripheral end of an outer ring 1 is provided with a shoulder slope 2 a of an inner ring 2.
A ball 5 held by a retainer 6 is interposed between the inner and outer rings 2 and 1.

The shoulder slope 2 of the inner ring 2 of the seal lip 4
As can be seen better in FIG. 2, a large number of two rows of convex portions 7 and 8 are uniformly arranged in the circumferential direction on the sliding contact surface 4a with respect to a. Further, the projections 7, 8
Is coated with a lubricating film 9 made of a low friction material of polytetrafluoroethylene. The height h of the projections 7 and 8 is set to 5 μm to 50 μm.

The height h of the projections 7 and 8 is 5 μm to 50 μm.
The reason for setting m is clear from FIG. 4 and FIG. FIG. 4 is a graph of test results of the height of the convex portion and the seal wear width, and FIG. 5 is a graph of a test result of the height of the convex portion and the amount of oil leakage. Here, the seal wear width refers to the sliding surface width of the seal lip portion. As for the seal wear width, the height of the projection is 5μ.
If it is less than m, it will be small and constant if it becomes 5 μm or more. That is, when the height of the convex portion is 5 μm or less, the oil pool, that is, the oil film is thin on the sliding surface of the seal lip, the contact area ratio of the seal rubber material is large, and the wear progresses quickly. On the other hand, when the height of the convex portion is 5 μm or more, the oil film on the sliding surface of the seal lip becomes thick and a lubricating oil film can be secured, so that the wear becomes almost constant. The amount of oil leak is
When the height h of the convex portion is 50 μm or less, the value is zero, but when the height h is 60 μm or more, the leakage is large. It is considered that the surface is not in contact with the entire circumference and a non-contact portion is formed, which causes oil leakage.
From the above, it can be understood that setting the height h of the convex portion to 5 μm to 50 μm is satisfactory in terms of seal wear and oil leakage.

The shapes of the projections 7 and 8 are shown in FIGS.
However, the present invention is not limited to the one shown in FIG. 3, but may be one in which convex portions 10 on a straight line extending a certain length in the axial direction are equally arranged in the circumferential direction as shown in FIG. 10 may be formed randomly in the circumferential direction.

Next, the operation will be described. The convex portions 7 and 8 of the sliding contact surface 4a of the seal lip 4 have a higher surface pressure at the portion facing the bearing rotation direction than at the portion facing the anti-rotation direction. There is a difference. For this reason, the gap between the respective convex portions, that is, the surface roughness can be maintained for a long time, and the lubricating oil pool due to the surface roughness can be secured for a long time. Also, due to the long-term accumulation of the lubricating oil, the seal lip 4
And the low torque can be maintained. Moreover,
Even if the bearing is used under low lubrication conditions, a low friction lubricating film provides low torque and wear resistance.

[0011]

According to the present invention, the surface roughness of the sliding contact surface of the seal lip of the seal ring can be maintained for a long time, and the lubricating oil film can be secured for a long time.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a rolling bearing sealing device of the present invention.

FIG. 2 is an enlarged view of a main part of the seal lip of the present invention.

FIG. 3A is another embodiment of the present invention, and FIG. 3B is an enlarged view of a main part.

FIG. 4 is a graph showing test results of a height of a convex portion and a width of wear of a seal.

FIG. 5 is a graph showing test results of the height of a convex portion and the amount of oil leakage.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer ring 2 Inner ring 2a Shoulder slope 3 Seal ring 4 Seal lip 4a Sliding surface 5 Ball 6 Cage 7, 8, 10 Convex part 9 Lubricating film

Claims (1)

[Claims] 1. A sealing device for a rolling bearing in which a seal lip of a seal ring fixed to one race is slidably contacted with a shoulder of the other race, wherein a circumference of a sliding contact surface of the seal lip is provided. In the direction, a number of protrusions having a height of 5 μm to 50 μm are formed randomly or in a predetermined arrangement, and the sliding contact surface including the protrusions is coated with a lubricating film made of a low friction material. Rolling bearing sealing device.