GB2177762A - Anti-friction bearing seal - Google Patents

Abstract

An improved seal for an anti-friction bearing in which a felt ring 32 is positioned between a pair of flingers or retainers 28, 30, at least one of which is adapted to rotate relative to the other. A felt engaging surface of one flinger 28 is coated with an anti-friction material 38, such as a nylon, to reduce the heat generated by the felt rotating and rubbing the surface of the coated flinger. <IMAGE>

Description

SPECIFICATION Improved bearing seal Anti-friction bearing assemblies, for example, of the ball or roller varieties, usually comprise, in addition to the inner and outer races and the particular anti-friction elements, means to seal the bearings against the ingress of dirt and other foreign material against the loss of lubricant.

This invention relates to improvements in bearing seals to seal the bearing against the ingress of dirt and other foreign material against the loss of lubricant.

Dlesk, U.S. Patent No. 1 420 416, describes a dustproof ball bearing in which an assembly of a felt ring and a washer of a metal or composition turning with the inner race is enclosed between interfitting cupshaped members, one turning with the inner race and one turning with the outer race, the washer substantially preventing wear on the felt ring.

Shafer, U.S. Patent No. 2 189 838, discloses a number of embodiments of bearing seals. Figs. 6 and 7 are particularly interesting, the seals shown therein comprising a felt or leather ring between an outer flinger or retainer pressed onto the inner race, and an inner flinger or retainer pressed onto the outer race. The retainers rotate relative to one another. The angular relation of the seal assembly to the bearing assembly enhances the retention of lubricant in the bearing assembly.

Firth, U.S. Patent No. 2 405 122, discloses, at each end of a bearing assembly, a felt pad between a pair of members, one frictionally secured to the inner race and the other to the outer race.

The improved bearing seal of this invention is similar to the seal described and illustrated in Figs. 6 and 7 of the Shafer patent, supra.

The seal of this invention comprises a pair of flingers or retainers positioned between the inner and outer races of an anti-friction bearing assembly with a ring of fibrous material, such as felt, therebetween. The inner flinger is pressed onto the outer race while the outer flinger is pressed onto the inner race. Generally the fibrous ring rotates with the outer flinger and thus frictionally rubs against a surface or surfaces of the inner flinger. The rubbing of the felt and the surface generates heat which causes deterioration of the felt, thus reducing the potential life of the felt ring. To replace the felt of the seal requires the removal of the bearing from service, thus increasing the cost of the service in which the bearing is used.

To reduce the friction between the felt and the surface or surfaces of the inner flinger, and thus to improve the reliability and life of the bearing, it is proposed to coat, at least the rubbing surface or surfaces of the inner flinger, with an anti-friction material, such as a nylon or other similar anti-friction material.

One suitable nylon is that known as Nylon 11, manufactured by the Rislan Corporation of Glen Rock, New Jersey. Nylon 11 can be applied to the flinger surface or surfaces as a powder by either an electrostatic or a fluid bed process, in thicknesses ranging from 0.0635 mm to 1.27 mm. After being applied, the coating is fused to the flinger at temperatures of 400 degrees F. to 450 degrees F.

(205 degrees C. to 230 degrees C.).

Figure 1 is a side elevational view of a bearing with seals constructed according to this invention; and Figure 2 is an enlarged fragmentary sectional view taken on line 2-2 of Fig. 1.

In Fig. 1, a pillow block 10 has a sealed bearing unit or assembly 12 mounted therein, the block 10 being provided with feet 14,16, having holes therethrough to receive bolts to rigidly attach the pillow block to a supporting surface. Shown also is an inner race 18, an outer race 20 and the bearing seal 22. A grease fitting 24 communicates with the interior of the bearing assembly for the introduction of lubricant thereinto.

In Fig. 2., the enlarged fragmentary view, the bearing assembly portion shown comprises the inner and outer races, 18 and 20, and a plurality of anti-friction elements 26 therebetween. The anti-friction elements shown are balls and only one is shown in the figure. Each bearing seal 22, there being a seal at each end of the unit, comprises an inner flinger or retainer 28 and an outer flinger or retainer 30, both being made of metal, such as a steel. A felt ring 32 is positioned between the inner and outer flingers in engagement with surfaces 28A and 28B of flinger 28 and surfaces 30A and 30B of flinger 30. The felt of the ring may be made of wool, naturally grown fibers, or of man-made fibers. A cylindrical part 34 of flinger 28 is pressed onto the outer race 20 and an annular flange 36 abuts an outer end of the race 20.

The surfaces 28A and 28B of the flinger 28 are rubbing surfaces, i.e., the felt, which turns with the inner race and thus the outer flinger 30, rubs against the surfaces 28A and 28B and generates heat. A relatively thin coating 38 of an anti-friction material (exaggerated in thickness in the drawing for purposes of illustration) is applied to the surfaces 28A and 28B to reduce the friction and thus the generated heat between the felt ring and the rubbing surfaces 28A and 28B. Preferably the material which is applied to the surfaces 28A and 28B is a nylon, known as Nylon 11, manufactured by the Rislan Corporation.

The outer flinger 30 of each seal has an annular part 40 and a cylindrical part 42, the latter being pressed onto the inner race 18.

The felt ring 32 is constrained between the inner and outer flingers, and because of this construction, the ingress of dirt and foreign material into the bearing as well as the loss of lubricant are substantially prevented.

The nylon is applied to the surfaces 28A and 28B by an electrostatic or a fluid bed process and then is fused thereto at a temperature of 205 degrees C to 230 degrees C.

The particular thickness of the coating is not generally critical, but is usually on the order of 0.635 mm, although it can be from 0.0635 mm to 1.27 mm.

While a ball bearing assembly is shown and described, it is to be understood that the invention is also applicable to other types of bearings, such as roller bearings and the like.

Also in some installations, only one seal at one end of a bearing may be used.

The appended claims are to be construed as broadly as the prior art will permit.

Claims (5)

1. A seal for bearings having inner and outer races and anti-friction elements therebetween, said seal comprising : a first flinger having an annular surface frictionally secured to said outer race; a second flinger having an annular surface frictionally secured to said inner race; said annular surfaces defining an annular space therebetween and one of said surfaces being rotatable with respect to the other; a fibrous annular member positioned between said surfaces in said space, said fibrous member being in contact with said surfaces; and an anti-friction coating on at least one of said surfaces to reduce friction with said fibrous material when one of said surfaces rotates relative to the other surface.

2. A seal as recited in claim 1, in which said fibrous material is a felt ring and said anti-friction material is a nylon.

3. A seal as recited in claim 2, in which said anti-friction coating is on said first-named annular surface.

4. A seal as recited in claim 2, in which said nylon is Nylon 11.

5. A seal as recited in claim 2 in which the thickness of said coating is between 0.0635 mm and 1.27 mm.