GB2150985A - A double row ball bearing assembly - Google Patents

Abstract

An arrangement for assembling and double row ball bearing comprises spacer elements 5 made integral with the respective outer races 4 and extending in comb- shaped fashion towards one another. At manufacture the spacers are fitted alternately one inside the other (Fig. 3 not shown), but for operating assembly of the bearing one set of spacers are removed axially and turned in relation to the other set of spacers until the end faces 7 of opposite projections bear against one another. A sleeve 6 having an axial slit 10 and snap element connections 11 extends around the spacers 5. <IMAGE>

Description

SPECIFICATION Bearing arrangement in O-configuration This invention relates to a bearing arrangement in O-configuration with two angularcontact bearings, the inner tracks of which are disposed on a common machine part and the outer rings of which are loaded radially and akially in relation to one another via rows of rolling bodies and are supported against one another via spacing devices. The invention also relates to a method of assembling this type of bearing arrangement.

A bearing arrangement of this type is already known through the GB-PS 542 669.

The inner tracks for two rows of balls are disposed on a shaft in one piece. Together with these, the outer rings each form an angular-contact ball bearing, the tracks being constructed in O-configuration. This means that the point of intersection of the resulting directions of force via both ball bearings is radially outside the bearing arrangement.As a result, a special assembly is necessary, during which a) one row of rolling bodies is placed on one of the inner tracks, b) one of the outer rings is mounted over the other track, which is still free, and pushed back towards the rolling bodies, c) the second outer ring is mounted over the track which is still free until it comes to bear against the first outer ring, d) the second row of rolling bodies is arranged on the other inner track, e) the second outer ring is pushed back towards the second row of rolling bodies, f) the two outer rings are supported against one another through spacing devices and g) the spacing devices are secured in their position.

The essential thing in this case is that in one of the last steps of assembly, spacing devices are inserted between the outer rings so as to adjust the outer rings in relation to the inner tracks. In the known construction, a radially divided spacer ring is used. An important disadvantage of this bearing arrangement is that this spacer ring has to be manufactured separately and its manufacturing tolerances are added to those of the two outer rings as a result of which there may be large errors in the dimensions as a whole. This applies in particular to the width and the variation in width over the circumference of the outer rings and of the spacer ring.As a result, it may happen, under normal manufacturing conditions, that on the one hand extremely different adjustment values result for the whole bearing arrangement within one production series and, on the other hand, unequal adjustment values occur, seen over the circumference. This seriously affects the life of the bearing arrangement and premature failure may occur. With the known construction, this disadvantage can only be avoided by ektremely accurate manufacture which would increase the cost of the bearing arrangement as a whole.

It is the object of the invention to provide a bearing arrangement of the type mentioned at the beginning and a method for its assembly as a result of which adjustment values are achieved which fluctuate little in the series and are uniform over the circumference of the bearing under normal manufacturing conditions.

The problem is solved in that the spacing devices are constructed in the form of combshaped, axially directed projections which can be fitted alternately one inside the other during assembly but bear against one another with their end faces in the assembled state and which are made integral with the outer rings, and during assembly, the second outer ring is fitted with its axial projections in the recesses disposed between those of the first outer ring until they come to bear comb-like one inside the other and after being pushed back towards the second row of rolling bodies is turned in relation to the first outer ring until the end faces of opposite projections bear against one another in coincidence.

As a result, further separate spacing devices are no longer necessary so that under normal conditions only the manufacturing tolerances of the two outer rings have to be reckoned with. Further inaccuracies in manufacture are no longer added thereto. The end faces of the projections are component surfaces of one side face of the outer ring and accordingly can be machined by turning just as if the side face were not interrupted. The outer rings are simply made wider than usual and provide intervening recesses according to the required number of projections. The boundary surfaces of the recesses do not need to be further machined because they do not contribute to the operation and accuracy of the bearing arrangement.The recesses may also be made broader, that is to sag wider in the circumferential direction, than the projections in order to achieve a circumferential play in the assembled state. In this case, machining tolerances and quality of the surfaces no longer play any part. The recesses are machined for example by milling, punching or breaking. It can be assumed that during the grinding of the end faces of the projections, the same high quality is achieved, particularly so far as the plane parallelism with respect to the other continuous side face of the outer ring is concerned, as in normal outer rings.Thus assurance is provided that, in the bearing arrangement according to the invention, a greater uniformity in the adjustment, seen over the circumference, is achieved and adjustment values of the whole bearing arrangement are achieved with considerably closer tolerances in series production. In addition, the assembly is simple and can be automated with little expense.

In one embodiment according to the invention, each outer ring comprises at least two projections. If two projections are provided they may appropriately be disposed situated diametrically opposite one another. This results in a spacing of 90 , that is to say a projection and a recess follow alternately in an angular step of 90 . The recesses must be somewhat wider in -the circumferential direction so as to be able to introduce the projections of the other outer ring. When the bearing arrangement is assembled, two diametrically opposite spacing webs result, each formed from two projections. As a result, two opposite recesses are formed in between in the circumferential direction. Three or more projections may, however, also be provided in which case the method can be applied equally advantageously.

In a preferred embodiment of the invention, the projections comprise rising ramps which are slightly inclined in relation to the circumferential direction, at one corner, in the region of the end faces. As a result, the mutual rotation of the outer rings is greatly simplified and even bearing arrangements with initial stress can be assembled in a simple manner.

During the turning of the outer rings, the corners in the region of the end faces of the projections of the one outer ring come onto the rising ramps of the other. During the further turning, the outer rings are parted axially until the end faces come to lie against one another. The corners no longer disturb one another in the course of this.

In another embodiment of the invention, the generated surfaces of the projections are disposed on a smaller diameter in comparison with the surface diameter of the outer rings and the annular free space thus formed is filled in by a sleeve-shaped cover in the assembled state.

The sleeve-shaped cover substantially closes the recesses between the projections and seals off the interior between the rolling bearings.

An annular free space is necessary so that the cover does not project radially beyond the generated surfaces of the outer rings. The cover may, for example, be a plastics sleeve which is capable of shrinking.

In a further embodiment of the invention, the sleeve-shaped cover comprises an axial slit and, in its region, snap elements cooperating with the projections. As a result, assembly is facilitated in that the cover is passed over the bearing arrangement by widening the slit and then contracts again into a sleeve. The snap elements may engage behind the projections through the recesses between the projections and at the same time advantageously form a protection against turning of the outer rings in relation to one another.

The invention is described below with reference to the example illustrated in the drawing.

Figure 1 shows the longitudinal section of a bearing arrangement with two angular-contact ball bearings in O-configuration, Figure 2 shows the cross-section on the line A-A of the bearing arrangement shown in Figure 1, Figure 3 shows the plan view of the outer rings fitted one inside the other during assembly and Figure 4 shows the plan view of the outer rings pushed apart and turned, in a further method step of assembly.

The bearing arrangement illustrated in Figure 1 consists of a one-piece bearing sleeve 2 carrying the two inner tracks 1, two rows of balls 3, two outer rings 4 with spacing devices 5 disposed in between them and a sleeve-shaped cover 6. The two ball bearings are constructed in the form of angular-contact ball bearings and assembled in an O-configuration. The spacing devices 5 are necessary to adjust the outer rings 4 axially outwards towards the rows of balls 3 or towards the inner tracks 1. They are each formed by four axially directed projections 5 which are made integral with the outer rings 4 and which bear against one another with their end faces 7 in the assembled state of the bearing arrangement.

As can be better seen from Figure 2, the four projections 5 are uniformly distributed at the, circumference of the outer rings 4 and have an arc length in the circumferential direction which is slightly smaller than the recesses 8 situated in between. As a result, the outer rings 4 can be fitted together in a comblike manner by the projections 5, as illustrated in Figure 3, so that the joint axial length is considerably shorter than in the fully assembled state when the end faces 7 of the projections 5 bear against one another as illustrated in Figure 1. This is the prerequisite for the use of the method of assembly of bearing arrangements in O-configuration, described in the GB-PS 542 669 and not illustrated here in the individual working steps, with, for example, a one-piece bearing sleeve 3 carrying the two inner tracks 1. In one of the last working steps, the outer ring 4, illustrated in Figure 3, is first pushed axially away from the other outer ring 4 in the direction shown by an arrow until the two outer rings 4 bear against the rows of balls 3 (c.f. Figure 1). Then the outer ring 4 illustrated on the right is turned in the direction of the arrow in relation to the other outer ring 4.

The turning is facilitated in that both outer rings 4 are mounted coaxially in relation to one another via the rows of balls 3. In addition, in order to reach the final position of assembly without disturbance, rising ramps 9 are provided on the end faces 7 of the projections 5, in the region of the corners, and prevent a mutual abutment of the projections 5 during the turning.

In Figure 4, the two outer rings 4 illustrated in the end position reached by the mutual turning. In this case, the end faces 7 of the projections 5 bear against one another and four spacing webs result which are distributed at the circumference with intervening recesses 8. These are closed by the sleeve-shaped cover 6 which engages positively in an annular free space. This is achieved in that the generated surfaces of the projections 5 lie on a smaller diameter than the generated surface of the outer rings 4. As is better illustrated in Figure 2, the sleeve-shaped cover 6 comprises an axial slit 20 as a result of which this can be passed over the bearing arrangement, after widening of the slit 10 radially, and then comes to lie in the annular free space. Provided in the region of the slit 10 are snap elements 11 which extend over the whole axial length of the cover 6 and engage radially behind the projections 5 through the recesses 8. As a result, the outer rings 4 are secured against turning in relation to one another.

Claims (6)

1. A bearing arrangement in O-configuration with two angular-contact bearings, the inner tracks (1) of which are disposed on a common machine part (2) and the outer rings (4) of which are loaded radially and axially in relation to one another via rows of rolling bodies (3) and are supported against one another via spacing devices characterised in that the spacing devices are constructed in the form of comb-shaped, axially directed projections (5) which can be joined alternately one inside the other during assembly but bear against one another with their end faces (7) in the assembled state and which are made integral with the outer rings (4).

2. A bearing arrangement as claimed in Claim 1, characterised in that each outer ring (4) comprises at least two projections (5).

3. A bearing arrangement as claimed in Claims 1 or 2, characterised in that the projections (5) comprises rising ramps, which are slightly inclined in relation to the circumferential direction, at one corner, in the region of the end faces (7).

4. A bearing arrangement as claimed in Claims 1 to 3, characterised in that the generated surfaces of the projections (5) are disposed on a smaller diameter in comparison with the surface diameter of the outer rings (4) and the annular free space thus resulting in the assembled state is filled in by a sleeveshaped cover (6).

5. A bearing arrangement as claimed in Claims 1 to 4, characterised in that the sleeve-shaped cover (6) comprises an axial slit (11) and, in its region, snap elements (11) cooperating with the projections (5).

6. A bearing arrangement substantially as hereinbefore described with reference to the accompanying drawings.