GB2212866A

GB2212866A - Improvements in or relating to ball bearings

Info

Publication number: GB2212866A
Application number: GB8728005A
Authority: GB
Inventors: Gerard Iain Madden
Original assignee: Torrington Co Ltd; Torrington Co
Current assignee: Torrington Co Ltd; Timken US LLC
Priority date: 1987-11-30
Filing date: 1987-11-30
Publication date: 1989-08-02
Anticipated expiration: 2007-11-30
Also published as: GB8728005D0; GB2212866B

Abstract

A ball bearing unit including two sets of retained balls (5) with inner and outer raceways (6, 8) for each set. At least one of the raceways is given a configuration in section of a concave portion (10) leading into a flattened portion (11) extending in a direction away from its adjacent concave portion beyond the balls. This construction is intended to act as an alternative to roller bearings in lightly loaded applications. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO BALL BEARINGS This invention relates to ball bearings.

With the present invention, it is intended to achieve an economic alternative to roller bearings in lightly loaded applications.

According to one aspect of the present invention, there is provided a ball bearing unit including retained balls and at least one raceway on which the balls can run, this raceway having the configuration in section of a concave portion leading into a flattened portion, on which flattened portion the balls are intended to run, said flattened portion extending in a direction away from the concave portion beyond the points of contact with said balls.

According to another aspect of the present invention, there is provided a ball bearing unit including two sets of retained balls and at least one raceway for each set of balls, each said at least one raceway having the configuration in section of a concave portion leading into a flattened portion, on respective ones of which the sets of balls are intended to run, each said flattened portion extending in a direction away from its adjacent concave portion beyond said balls.

Said at least one raceway may be an outer raceway or it may be an inner raceway. Both inner and outer raceways may be provided. The inner raceway may be formed on a roll or shaft or on an inner ring fitted on the roll or shaft. The outer raceway may be formed on a ring fitted in an outer body.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawing, in which: Figure 1 is a diagrammatic view partly in section of a first form of ball bearing unit, Figure 2 is a view similar to Figure 1 of a second form of ball bearing unit, Figure 3 is a view similar to Figure 1 of a third form of ball bearing unit, and Figure 4 is a view similar to Figure 1 of a fourth form of ball bearing unit.

Referring firstly to Figure 1 of the drawing, the ball bearing unit includes two ball bearings 1 and 2, one being a mirror image of the other and each including outer rings 3 which are both set in a body 4.

Respective sets of balls 5 are retained in raceways 6 of the outer rings 3 by means of cages 7. The sets of balls are arranged to run on inner raceways 8 formed on a profiled shaft 9.

The raceways 8 are mirror images of one another and each have a configuration in section of a concave portion 10 leading into a flattened portion 11, on which flattened portion the balls 5 can run, the flattened portions 11 extending in a direction away from the concave portions 10 beyond the points of contact with the balls.

The concave portions 10 face towards the respective ends of the shaft 9 and it will be seen that they serve to limit relative axial play between the shaft and the body 4. A certain amount of clearance also exists between the balls 5 and the outer raceways 6 so that not only is play allowed between the inner raceways 8 and the balls 5 but also between the balls 5 and the outer raceways 6. The inner raceways 8 are by virtue of their curved portions able to accept small thrust loads, as are the outer raceways. These points also apply to the other embodiments described herein.

In the embodiment shown in Figure 2, the ball bearing unit comprises two ball bearings 12 and 13, each of which comprises an outer ring 14, sets of balls 5 retained in cages 15 and an inner roll or shaft 16.

In this embodiment, the shaft 16 has two annular grooves 17 forming raceways for the respective sets of balls, whilst the outer rings 14 have raceways 18 for the respective sets of balls 5. As with the raceways 8, each raceway 18 has a configuration in section of a concave portion 19 leading into an adjacent flattened portion 20 extending in a direction away from its adjacent concave portion beyond the balls 5, the flattened portions 20 forming the regions on which the balls 5 can run.

As with the embodiment shown in Figure 1, each ball bearing is a mirror image of the other but in the embodiment of Figure 2 the curved portions 19 face one another with the flattened portions 20 being closer to one another than the curved portions 19 and it is these profiles which act together to limit relative axial play between the shaft 16 and the body 4.

In assembling the embodiment of Figure 1, the cages would be mounted concentrically with their outer rings and then the balls are pushed in to a unitary assembly.

The bearing assembly can then be fitted about the shaft (or the shaft pushed in the assembly).

In the embodiment of Figure 2, the outer rings 14 are separable from the remainder of the bearing assembly whilst the cage and ball assembly are intended to stay together and can form a composite assembly with the shaft.

The shafts of both Figures 1 and 2 show gearing 21 but it will be appreciated that other arrangements are possible.

Referring now to Figure 3, this embodiment is similar to Figure 1 except that, instead of-the inner raceway being formed directly on the shaft 22, inner rings 23 are fitted on the shaft and it is these inner rings 23 which have the raceways 8 formed on them, the rings 23 abutting outwardly-facing shoulders 22A on the shaft.

Figure 4 employs the principle of the embodiment of Figure 3 as applied to the Figure 2 embodiment and like parts are given like reference numerals, with the inner raceways 17 being formed on inner rings 24 abutting the shoulders 22A of the shaft 22.

With the Figure 3 embodiment, the outer rings, cages and balls can form a unitary assembly mountable about the inner rings whereas in Figure 4 the inner rings, cages and balls can form a unitary assembly with the outer rings being fitted subsequently.

The rings 23 and 24 allow the bearing to be utilised in a case where the shaft is comparatively soft and therefore the rings 23 and 24 are of a harder-wearing material.

In both Figures 3 and 4, the shoulders 22A could be in reversed positions, i.e. facing one another with the respective inner rings 24 between them. Indeed, with the Figure 2 embodiment, the concave portions 19 of the outer rings 14 could be reversed so they are located between the balls 5 and the gearing 21 and face axially outwardly of the shaft.

In all of the embodiments, both inner and outer raceways of a pair of raceways may be formed with said flattened and curved portions, the curved portions diagonally opposing one another as a mirror image. In the embodiments shown, two pairs of raceways are illustrated but it will be appreciated that only one of the pairs need be provided with the raceway having the flattened portion.

All of the embodiments are intended to form an economical alternative to roller bearings in lightly loaded applications and have the advantages of reducing skidding at high speeds, cheapness of manufacture, are more tolerant of accidental axial preload whilst eliminating small, difficult to manufacture and measure raceway corner radii and eliminate shaft stress raisers. Under combined loading (i.e. axial and radial loading) , reduced friction torque is experienced and the assemblies are more tolerant of misalignment.

Claims

CLAIMS:

1. A ball bearing unit including retained balls and at least one raceway on which the balls can run, this raceway having the configuration in section of a concave portion leading into a flattened portion, on which flattened portion the balls are intended to run, said flattened portion extending in a direction away from the concave portion beyond the points of contact with said balls.

2. A ball bearing unit including two sets of retained balls and at least one raceway for each set of balls, each said at least one raceway having the configuration in section of a concave portion leading into a flattened portion, on respective ones of which the sets of balls are intended to run, each said flattened portion extending in a direction away from its adjacent concave portion beyond said balls.

3. A ball bearing unit according to claim 2, wherein the ball bearings comprising the two sets of retained balls and said at least one raceway for each set of balls are mirror images of one another.

4. A ball bearing unit according to claim 2 or 3, wherein said concave portions of the respective raceways for each set of balls face away from one another.

5. A ball bearing unit according to claim 2 or 3, wherein said concave portions of the respective raceways for each set of balls face towards one another.

6. A ball bearing unit according to any one of the preceding claims, wherein said at least one raceway is an outer raceway.

7. A ball bearing unit according to claim 6, wherein said outer raceway is formed on a ring fitted in an outer body.

8. A ball bearing unit according to any one of claims 1 to 5, wherein said at least one raceway is an inner raceway.

9. A ball bearing unit according to claim 8, wherein said inner raceway is formed on a roll or shaft.

10. A ball bearing unit according to claim 8, wherein said inner raceway is formed on an inner ring fitted on a roll or shaft.

11. A ball bearing unit according to any one of the preceding claims and comprising inner and outer raceways which are a mirror image of one another.

12. A ball bearing unit, substantially as hereinbefore described with reference to Figures 1 and 2 or Figures 3 and 4 of the accompanying drawings.