GB2249156A

GB2249156A - A bearing assembly for a universal joint

Info

Publication number: GB2249156A
Application number: GB9121441A
Authority: GB
Inventors: Lindenthal Hans
Original assignee: JM Voith GmbH
Current assignee: JM Voith GmbH
Priority date: 1990-10-24
Filing date: 1991-10-08
Publication date: 1992-04-29
Also published as: GB9121441D0; JPH06341448A; DE4033753C1; FR2668562A1

Abstract

An assembly for two movable parts in a joint for an articulated shaft, preferably a journal crosspiece (1) and a joint fork (2) increases the dynamic and static carrying capacity by the provision of two cylindrical roller bearings (7, 3) acting in parallel. The bearings (3, 7) have different diameters and are disposed axially nesting partly inside one another on the journal crosspiece (3). In this way it is possible to use a plurality of rows of cylindrical rollers for transmitting circumferential force within the contour of the joint predetermined by the external diameter of the joint and to utilize the available space In an optimum manner. <IMAGE>

Description

224,?130 1 AN ASSEMBLY FOR A UNIVERSAL JOINT This invention relates in

general to a universal joint, and more especially to an assembly with bearings between two relatively movable components, for example a journal crosspiece and a joint fork. A universal joint of this kind is known from DE-PS 26 26 960.

In the designing of drives with universal joints and articulated shafts, the problem frequently arises that the torque to be transmitted requires a rotational diameter which cannot be accommodated within the space available. This is especially a problem in rolling mill drives, where joints comprising plain bearings are to be replaced by universal joints having rolling contact bearings. The advantage of the plain bearing is the small dimensions needed but the life and the play that occurs in operation in plain bearings are not satisfactory. A disadvantage of plain bearing joints is, furthermore, the large amount of lubricant required, which escapes during operation and fouls the environment.

With the known universal joint, it has been attempted to accommodate a roller bearing having a higher dynamic and static load-bearing capacity within a given external diameter. For this purpose, the journal cross piece is constructed along the journal axis with two different diameters, i.e. it tapers outwards by steps. This serves on the one hand for enabling the journal 2 crosspiece to be passed through the bores of the forked eyes of the single-piece joint fork. The smaller, stepped-down part of the crosspiece, on the other hand, is utilized for the mounting of an additional roller bearing, disposed radially further outwards. This produces an increase in the load-bearing capacity, but the construction is still not entirely satisfactory especially in respect of the working life.

An object of the present invention is further to improve the known assembly and to increase further its static and dynamic load-bearing capability while maintaining the same external diameter.

According to the invention there is provided an assembly for use between two relatively movable component parts of a universal joint or an articulated shaft, for example a journal crosspiece and a joint fork, wherein one component e.g. the crosspiece orientated radially outwards and substantially journal-shaped relative to a journal axis is stepped down in diameter radially outwards and, for transmitting torque, possesses rolling contact bearings comprising at least two rows of cylindrical rollers on different track diameters and the radially outermost bearing of smaller diameter is disposed, along the journal axis to at least partly extend over the width of the radially innermost bearing of larger diameter. In accordance with the invention, 1 3 two roller bearings of different diameters can be housed within one joint. The roller bearing of larger diameter is situated at a shorter distance from the axis of rotation than the roller bearing of smaller diameter. The latter, however, is partly recessed axially within the larger roller bearing. In this way it is possible to arrange both roller bearings as far as possible radially outwards from the axis of rotation and to choose their diameters as large as possible with the radially outermost edges of each of the two bearings being situated near to the outer diameter of the joint. With this measure, an advantageous utilization of the circular cross-section available and an increase in the carrying capacity of the assembly, or joint which can amount to up to 40%, are achieved.

The depth of penetration or recessing of the smaller bearing corresponds to at least one-quarter of the roller width of the larger bearing, while the internal diameter of the smaller bearing shall be at least two-thirds the diameter of the larger bearing. At least one of the two bearings an d preferably the larger bearing, preferably has a separate outer ring while the outer roller track for the rollers of the smaller bearing may be constructed as a hardened roller track on the joint fork itself. Each of the two fork eyes can, be provided with a bearing cover. The two mutually aligned bearing covers can then be connected together by means of a journal cross anchor, 4 which extends through a bore in the journal crosspiece. These bearing covers are centred in the joint fork and secured against twisting. Alternatively, the outer roller track for rollers of the smaller bearing may also be disposed on the bearing cover. An abutment disc between the end face of the journal crosspiece can serve for the axial guidance of the journal crosspiece between the two bearing covers, and it is possible for this abutment disc simultaneously to form also the axial holding for the inner ring of the smaller bearing. The abutment disc may be either of metal, preferably brass or bronze, or of plastics material, preferably a glassfibre-reinforced plastics.

The invention will now be described in more detail with reference to the accompanying drawings which illustrate embodiments of the invention. In the drawings Figure 1 is a longitudinal section through part of a universal joint in the region of an assembly constructed in accordance with the invention; Figure 2- a longitudinal section similar to Figure 1, with an alternative bearing arrangement; Figure 3 a cross-section through the mounting assembly shown in Figure 2, the view being taken along the line III-III in Figure 2; and Figure 4 is a longitudinal section through part of another modified assembly.

Figure I is a section through part of a universal joint between a journal crosspiece 1 and a joint fork 2, viewed along the axes of rotation 15, 16. The joint is overall similar to that described in DE-PS 2626960. The journal crosspiece 1 has a first bearing seating 10 having the diameter D and, radially further out from the axis of rotation 15, a second bearing seating 11 having a smaller diameter d. On the bearing seating 10 there is disposed, a cylindrical roller bearing 3 having a plurality of rows of cylindrical rollers 4 between an inner ring 5 and an outer ring 6. On the bearing seating 11 there is disposed a cylindrical roller bearing 7 having cylindrical rollers 8 and an inner ring 9. This bearing is of smaller diameter and width than the bearing 3 and the smaller bearing 7 is so arranged that it is situated, in the axial direction, partly alongside the larger bearing 3. In other words the bearing 7 penetrates with its width b by the depth of penetration t into the width B of the larger bearing 3. The penetration depth t is preferably about one-quarter of the width B. The diameter ratio d of the bearing seating 11 of the smaller bearing 7 to the diameter D of the bearing seating 10 of the larger bearing 3 is preferably 2:3. In this way a mutual relationship is obtained which permits optimum arrangement of the two bearings within the radius R defining the outer contour of the joint. More particularly it is possible to house, within the 6 predetermined space, as many rows of cylindrical rollers 4, 8 as possible on the largest possible diameter, in order to increase the carrying capacity of the whole assembly.

The large bearing 3 has a discrete outer ring 6, because there is sufficient room in this region. Instead of an outer ring for the smaller bearing 7, the fork eye itself has an outer roller track 21 for the cylindrical rollers 8. In this way the diameter d for the bearing seating 11 can be made sufficiently large. The advantage of this arrangement is, furthermore, that the outer roller track 21 for the smaller bearing 7 and also the bore for the outer ring 6 of the larger bearing 3 are situated on the same component, namely the joint fork 2, and therefore can be made with great precision. This is a form of construction for the joint fork, in which the two complementary joint forks are separate from one another. As shown there is a bearing cover 12, in one of the eyes of the fork 2 which is connected with a similar bearing cover of the opposite joint fork eye (not illustrated) by a journal cross anchor 13. This journal cross anchor 13 passes through a bore 14 in the journal crosspiece 1. The bearing cover 12 has an inner seating surface for the fitting of an abutment disc 19, against which the journal crosspiece 1 bears with its end support face 20. The axial end face of the inner ring 9 of the 1 7 bearing 7 constitutes a similar support surface for the disc 19, so that this disc 19 can accept also axial forces from the inner ring 9 and at the same time form the axial retainer for this inner ring 9.

In Figure 2, an alternative form of construction of the bearing between a bearing crosspiece 1 and a joint fork 3 comprising two cylinder roller bearings 3 and 7 analogous to the construction of Fig. 1 can be seen. In this embodiment, however, a bearing cover 12a has the same outer diameter as the outer ring 6 of the larger bearing 3. Assembly in this case takes place radially from the outside, because this is a joint of single-piece construction. The bearing cover 12a has an outer roller track 21a for the cylindrical rollers 8 of the smaller bearing 7. The bearing cover 12a must be exactly centred in the bore of the joint fork 3 and for this purpose the cover has a centering projection extending radially, as viewed from the axis of rotation 1, into the region of the cylindrical rollers 8, and therefore partly also into the region of the outer ring 6 for the larger bearing 3. The remainder of the construction of the mounting corresponds to that of Figure 1.

Figure 3 shows a longitudinal section through the joint according to Figure 2. Here it can be seen that a rotation prevention means for the bearing cover 12a, namely pins 17 in the radially outer region of the bearing cover 12a are provided. These pins 17 engage 8 into grooves 18 in the joint fork 2.

Figure 4 shows an alternative form of construction for the axial support of the journal crosspiece I against the bearing cover 12a. For this purpose, the inner ring 9 for the smaller bearing 7 has a widened-out shape providing an end support surface 20a, which is approximately equal in size to the support surface on the disc 19. The journal crosspiece 1 bears radially inside against the inner ring 9. The advantage of this embodiment is that an undivided support surface for the disc 19 is provided in order to reduce possible wear.

The disc 19 itself may be of metal, preferably brass or bronze, or of plastics, preferably a glass-fibrereinforced plastics.

1 9

Claims

1. An assembly for use between two relatively movable component parts of a universal joint or an articulated shaft, wherein one component orientated radially outwards and substantially journal-shaped relative to a journal axis is stepped down in diameter radially outwards and, for transmitting torque, possesses rolling contact bearings comprising at least two rows of cylindrical rollers on different track diameters, and the radially outermost bearing of smaller diameter, is disposed, along the journal axis to at least partly extend over the width of the radially innermost bearing, of larger diameter.

An assembly according to Claim 1, wherein depth of penetration of the smaller bearing over the width of the larger bearing corresponds at least to one-quarter of the width of the cylindrical rollers of the larger bearing.

3. An assembly according to Claim 1 or 2, wherein the diameter ratio of the bearing seatings of the inner bearing to the outer bearing is greater than 2:3.

4. An assembly according to any one of Claims 1 to 3, wherein at least one of the two bearings has an outer ring.

5. An assembly according to Claim 4, wherein the larger bearing has an outer ring, which is supported in said one of the two movable component parts.

6. An assembly according to any one of Claims 1 to 5, wherein the one movable component part has a hardened 2 outer roller track for the cylindrical rollers of the smaller bearing.

7. An assembly according to one of Claims 1 to 6, wherein the other component part is provided with a bearing cover, which is connected to a similar bearing cover by a journal cross anchor extending through a bore in the one component part.

8. An assembly according to claim 7 wherein the bearing covers are centred in bearing eyes of the other component part and are secured against rotation.

9. An assembly according to Claims 7 or 8, wherein the or each bearing cover has an outer roller track for the cylindrical rollers of the smaller bearing.

10. An assembly according to one of Claims 7 to 9, wherein the axial guidance of the one component part along the journal axis between the bearing covers is established by axial abutment discs.

11. An assembly according to Claim 10, wherein the inner ring of the smaller bearing forms, together with the axial end face of the one component part, a common bearing surface for one of the abutment discs, so that the abutment disc forms an axial stop for the inner ring of the smaller bearing.

12. An assembly according to Claim 10 or 11, wherein abutment discs are made of metal, preferably brass or bronze.

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13. An assembly according to Claim 10 or 11, wherein the abutment discs are made of plastics material, preferably a glass-fibre-reinforced material.

14 An assembly or a joint incorporating such as an assembly substantially as described with reference to and as illustrated in any one or more of the Figures of the accompanying drawings.