GB2045871A

GB2045871A - Roller bearings and their manufacture

Info

Publication number: GB2045871A
Application number: GB7910273A
Authority: GB
Original assignee: SAPCO Pty Ltd
Current assignee: SAPCO Pty Ltd
Priority date: 1979-03-23
Filing date: 1979-03-23
Publication date: 1980-11-05

Abstract

In practice, conveyor rollers tend to use bearings mounted on a shaft passing through a roller and it is desirable to provide a less costly arrangement. For this purpose, the invention provides a unit having inner and outer races, receiving suitable bearings (26) and being rotatable with respect to one another about an axis of rotation. One of the races (24) extends from a mounting element (24.5) in the direction of said axis and is fixed rigidly to the element. When the mounting element is attached to a support, the one race forms the sole carrier for the other race and the bearings, and any roller tube carried thereby. The specification also discloses a method of forming such a unit primarily from pressed steel. <IMAGE>

Description

SPECIFICATION Roller bearings and their manufacture This invention relates to units having inner and outer races which are rotatable with respect to one another, to a method for their manufacture, and to roller assemblies and roller conveyors.

According to the invention, there is provided a unit having inner and outer races receiving suitable bearings and being rotatable with respect to one another about an axis of rotation, one of the races extending from a mounting element in the direction of said axis and being fixed rigidly to the element so that, when the mounting element is attached to a support, the one race forms the sole carrier for the other race and the bearings.

The one race may comprise a pressed steel element which is tubular along at least the major part of its length. This pressed steel element can form the whole of one race, the mounting element being fixed to one end of the race and a groove being formed around the periphery of the race adjacent to its opposite end. The mounting element may be integral with the one race, and may comprise flange means extending outwardly away from the one race for fitting onto a bracket having inturned formations.

The outer race can be defined by an outer race element and a further element, the outer race element being rigidly attached to the further element. The outer race element may have an outer flange fixed rigidly in a groove in the further element and trapped between a shoulder and a wall of the further element. Preferably, the outer race element and further element are also pressed steel elements.

The invention also extends to a roller assembly comprising a roller tube and bearing units carrying the tube and located at opposite ends of the tube to enable the tube to rotate about an axis of rotation, the bearing units each comprising inner and outer races receiving suitable bearing and a mounting element fixed to one of the races for attaching the unit to a support, the races fixed to the mounting elements extending towards one another and away from the mounting elements so that the other races, bearings and roller are carried solely on those races when the mounting elements are attached to supports.

The conventional roller shaft can thus be eliminated, reducing the overall weight of the assembly.

The tube can be fixed to the other races by a mount located at least partly within the roller tube and fixed to an outer race element forming the major part of the other race. The outer race element is desirably attached to the mount by an annular flange projecting into an annular groove formed in the mount.

In order to further reduce the weight of the assembly, the one race may be tubular over at least a major part of its length and may have a substantially cylindrical surface for engagement by the bearings so as to allow the roller tube a limited amount of axial movement with respect to the other race. The one race can comprise a pressed steel element.

The invention further extends to a roller conveyor comprising a pair of side frames a plurality of roller assemblies mounted on and extending generally between the side frames, at least some of the roller assemblies each comprising a roller tube and independent bearing units located at opposite ends of carrying the tube, the bearing units each comprising an inner race, a mounting element supporting the inner race, an outer race connected to the respective tube and bearings located in the races to allow rotation of the races with respect to one another, wherein the side frames and mounting elements are provided with mating formations by means of which the pre-assembled roller assemblies can be mounted on the side frames.

The mating formations on the side frames may have inturned elements defining grooves facing towards one another and the mounting element may comprise flange means received within these grooves.

Also according to the invention, there is provided a method which comprises pressing flat stock to form a hollow inner race member, forming a groove in the periphery of said inner race member to form an inner race, locating bearings in the groove, and encircling the inner race member with an outer race to trap the bearings between the inner and outer races.

The groove may be formed during the pressing operation or in a subsequent spinning process.

A mounting means is preferably formed integrally with the inner race member during the pressing operation and is preferably a flange at one end of the inner race member. The central portion of the inner race member may then be tubular and its opposite end may be closed.

The outer race may be provided by pressing an outer race member and a further member from flat stock, the members each having therein a hole for receiving the inner race, locating these members about the inner race with one member encircling another, and deforming at least one of the members to trap the other members in place. For example, the further member may be initially cupped and may have a central portion extending along the axis of the inner race member. This portion may be deformed to a condition in which it traps the outer race member in place encircling the bearings. At this stage, the outer race member may be completely encircled by outer portions of the further member, which may be used to form a mount that is particularly suitable for location in a roller tube.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure lisa plan view of part of a roller conveyor; Figure 2 is a cross-section through part of the conveyor of Figure 1; Figure 3 shows an inner race and mounting element of the conveyor; Figure 4 is a side elevation of a bearing unit of the conveyor seen from one side of the unit; Figure 5 is a view from the opposite side of the bearing unit; Figure 6 illustrates a four stage forming process in the production of the inner race and mounting element; Figure 7 shows the inner race and mounting element in the various stages of its formation; Figures 8 and 9 shows an interim condition of the inner race and mounting element during the fourth stage of its production, being plan view and side elevation, respectively;; Figure 70 is a side elevation of the inner race and mounting element; Figure 11 is a cross-section through an outer race element prior to assembly of the unit; Figure 12 is a cross-section through a mount prior to assembly of the unit; Figure 13 shows a first stage during assembly; and Figure 14 shows a second stage during assembly.

The r oller conveyor shown comprises a pair of side tames 10 and a plurality of roller assemblies 12 mounted on the side frames. As the side frames and opposite halves of the roller assemblies are mirror images of one another, taken about the centre line of the roller assemblies, a cross-section through only parL' of the conveyor in the region of one side of a single roller assembly is shown in Figure 2.

The roller assembly has a roller tube 14 and bearing units 16 are located at opposite ends of the tube. Each bearing unit includes a pressed steel mount 18 having a cylindrical portion 18.1 fixed within the tube 12 and provided at one end with an annular flange 18.2 engaging the end of the tube.

The cylindrical portion 18.1 may be a tight press fit in the tube.

Atthe opposite end of the portion 18.1 to the flange 18.2, there is an inwardly directed step 18.3 which is slightly concave. The step merges with a retaining portion 18.4 of S-shaped cross-section defining radially outer and inner annular grooves 18.5 and 18.6, respectively. The inner groove is further from the flange 18.2 than the outer groove and that part of the retaining portion which borders the outer groove forms a shoulder 18.7 within the mount.

The opposite end of the retaining portion to the step 18.3 merges into a dished annular wall 18.8 having a central ring 18.9 forming one side of a ball race 20.

A dished, pressed steel outer race element 22 has a radially outer peripheral flange 22.1 which is fixed rigidly in the inner groove 18.6 of the mount between the shoulder 18.7 and the wall 18.8. An annular central portion 22.2 of the element provides an outer running surface of the ball race 20. The central portion 22.2 merges with an inwardly extending ring 22.3 forming the opposite side of the race to the ring 18.9.

An inner race 24 projects through the outer race element 22 and the mount 18. This inner race is formed from pressed steel and is hollow, being tubular along most of its length. However, one end 24.1 of the race is closed and an annular groove 24.2 has been rolled into the periphery of the race adjacent this end. The groove has a cylindrical bottom surface 24.3 and outwardly diverging side walls 24.4. As shown in Figure 3, the race 24 is formed integrally with a mounting plate 24.5 which extends radially outwardly away from the periphery of one end of the inner race.

Instead of being completely round, the race may be slightly squared off as it approaches towards the mounting element as shown in chain iines in Figure 3.

Roller bearings 26 are received in the inner and outer races and allow the outer race to rotate about the inner race.

The side frame have integral brackets which are formed by L-shaped formations 28 pressed into the frames for forming claws for engaging around the opposite sides of the mounting elements 24.5 and projections 30 also pressed into the side frames for engaging and supporting the bottoms of the mounting elements 24.5. If desired, inverted U-shaped slots can be cut into the side frames above the projections 30 to form tongues and these tongues may have holes through which a tommy bar may be passed for deforming the tongue so that it extends into the hollow centre of the inner race for trapping the inner race in position.

It will be clear that the pre-assembied roller assemblies can be mounted on the side frames relatively simply by placing the mounting elements into the brackets on the side frames and that complicated assembly work is therefore eliminated.

Once the mounting elements, and thus the inner races, have been located in place, the rollers are carried by and rotate about the inner races on the bearings 26. The cylindrical bottom surface 24.3 in the inner ball races allow the bearings to move for a limited distance axially of the axles while the outer race element, mount and tube rotate about an axis of rotation 32.

In order to assemble the bearing unit, the inner race and mounting element are formed simultaneously in a four stage pressing operation iliustrated with reference to Figure 6 to 9.

As shown in Figure 6 and 7, flat stock 34 is fed in direction 36 to a first die station 38. At this die station, the stock is cut along lines 40 to form a square stock section 42 which is still attached to the flat stock 34 at location 44.

The flat stock is then moved through a distance equal to the width of the stock section 42 and the stock section originally at the first die station 38 is moved to a die station 46. Once the stock section is in this position, it is pressed while it remains attached to the flat stock 34 at location 44. The resulting pressed element is illustrated at 42.1.

The flat stock is then moved in the direction 36 through a further distance corresponding to the width of the stock section 42 until the pressed section 42.1 has moved to a third die station 48.

Once the section is in this position it is again pressed to provide the inner race with the major part of its tubular shape, the resulting pressed section being shown at 42.2 in Figures 6 and 7. The section 42.2 is still attached to the flat stock 34 at location 44.

Finally, the flat stock 34 is moved again through a distance equal to the width of the stock section 42 to a final die station 50. Here, the peripheral part of the section 42.2 is initially pressed by a die to form a flattened zone 52 (Figures 8 and 9) around the periphery of the inner race portion and the die continues to move until it severs excess material, leaving the substantially square mounting element 24.5, and flattens the top of the inner race portion of the section.

The annular groove 24.2 of the inner race may be pressed into the inner race portion at its fourth station but may normally be formed in the inner race portion by a subsequent spinning process.

Naturally, the process described is continuous so that as soon as one pressed section leaves the fourth station another is moved into it.

The resulting inner race and mounting element is shown in Figures 3 and 10.

An outer race member 54 and a mount member 56 are pressed from flat stock in other pressing operations, each of these members having a central hole 58 which is only slightly greater than the diameter of the inner race 24.

The inner race 24 is then passed through the hole 58 in the outer race member 54 to the position shown in Figure 13 and ball bearings 60 are located in the member 54 around the periphery of the inner race 24. The member 54 is then gripped firmly by equally spaced die fingers (not shown) in an annular region 62, four equally spaced die fingers preferably being used. The die fingers may each have a surface for engaging the member 54 over an angle of about 30 degrees around its periphery.

The mount member 56 is then placed over the inner race 24 and member 54 and is pressed downwardly onto the outer race member 54, the die fingers serving to locate the member 54 accurately within the member 56.

A plurality of fingers (not shown) then engage the member 56 in the region of an annular zone 64 and press inwardly on the member 56 to begin to collapse the member inwardly. Meanwhile, a lock ring (not shown) moves downwardly to engage the mount member 56 at an annular zone 66 to prevent the mount member from collapsing in the region of the hole 58. Further die pieces then apply intense pressure to the mount member 58 at an annular zone 68.

During this whole process, the die fingers are holding the outer race member accurately in position with respect to the mount member and are forcing it upwardly within the mount member.

Thus, when the die finally applies substantial pressure to the opposite axial ends of the mount member 54, pressure still being applied in the region of zones 64 and 68 and the lock ring remaining in place, the mount member is collapsed onto the outer race member. The collapsed mount member adopts the shape shown in Figure 2 and thus forms the mount 18 of the bearing unit. The outer race member 54 is also slightly deformed so that it forms the outer race element 22 of the bearing unit in Figure 2.

During this process the inner race is accurately located so that the ball bearings 60 move into the annular groove 24.2 in the inner race and are trapped by the outer race element, thus forming the ball bearings 26 of the bearing unit of Figure 2.

It is thus possible to form a complete bearing unit, apart from the ball bearings, by pressing flat stock. In practice, steel will normally be used.

Claims

1. A unit having inner and outer races receiving suitable bearings and being rotatable with respect to one another about an axis of rotation, one of the races extending from a mounting element in the direction of said axis and being fixed rigidly to the element so that, when the mounting element is attached to a support, the one race forms the sole carrier for the other race and the bearings.

2. The unit of claim 1, wherein the one race comprises a pressed steel element which is tubular along at least the major part of its length.

3. The unit of claim 2, wherein the pressed steel element forms the whole of one race, the mounting element being fixed to one end of the race and a groove being formed around the periphery of the race adjacent to its opposite end.

4. The unit of any preceding claim, wherein the mounting element is integral with the one race.

5. The unit of any preceding claim, wherein the mounting element comprises flange means extending outwardly away from the one race for fitting onto a bracket having inturned formations.

6. The unit of any preceding claim, wherein the other race is defined by an outer race element and a further element, the outer race element being rigidly attached to the further element.

7. The unit of claim 6, wherein the outer race element has an outer flange fixed rigidly in a groove in the further element and trapped between a shoulder and a wall of the further element.

8. The unit of claim 6 or claim 7, wherein the outer race element and further element are pressed steel elements.

9. A roller assembly comprising a roller tube and bearing units carrying the tube and located at opposite ends of the tube to enable the tube to rotate about an axis of rotation, the bearing units each comprising inner and outer races receiving suitable bearings and a mounting element fixed to one of the races for attaching the unit to a support, the races fixed to the mounting elements extending towards one another and away from the mounting elements so that the other races, bearings and roller are carried solely on those races when the mounting elements are attached to supports.

10. The assembly of claim 9, wherein the tube is fixed to the other races by a mount located at least partly within the roller tube and fixed to an outer race element forming the major part of the other race.

11. The assembly of claim 10, wherein the outer race element is attached to the mount by an annular flange projecting into an annular groove formed in the mount.

12. The assembly of any one of claims 9 to 11, wherein the one race is tubular over at least a major part of its length and has a substantially cylindrical surface for engagement by the bearings so as to allow the roller tube a limited amount of axial movement with respect to the other race.

13. The assembly of any one of claims 9 to 12, wherein the one race comprises a pressed steel element.

14. A roller conveyor comprising a pair of side frames and a plurality of roller assemblies mounted on and extending generally between the side frames, at least some of the roller assemblies each comprising a roller tube and independent bearing units located at opposite ends of and carrying the tube, the bearing units each comprising an inner race, a mounting element supporting the inner race, an outer race connected to the respective tube and bearings located in the races to allow rotation of the races with respect to one another, wherein the side frames and mounting elements are provided with mating formations by means of which the preassembled roller assemblies can be mounted on the side frames.

15. A conveyor according to claim 14, wherein the mating formations on the side frames have inturned elements defining grooves facing towards one another and wherein the mounting element comprises flange means received within these grooves.

16. The conveyor of claim 15, wherein each inner race comprises a pressed steel element which is tubular along at least the major part of its length and which is integral with the associated mounting element.

17. The conveyor of claim 16, wherein each pressed steel element forms the whole of an inner race, the mounting element being located at one end of the race and a groove being formed around the periphery of the race adjacent to its opposite end.

18. A method which comprises pressing flat stock to form a hollow inner race member, forming a groove in the periphery of said inner race member to form an inner race, locating bearings in the groove, and encircling the inner race member with an outer race to trap the bearings between the inner and outer races.

19. A method according to claim 18, wherein a mounting means is formed integrally with the inner race member during the pressing operation.

20. A method according to claim 19, wherein the mounting element is a flange at one end of the inner race member.

21.A method according to claim 20, wherein the central portion of the inner race member is tubular and its opposite end is closed.

22. A method according to any one of claims 18 to 21, wherein the outer race is provided by pressing an outer race member and a further member from flat stock, the members each having therein a hole for receiving the inner race, locating these members about the inner race with one member encircling another, and deforming at least one of the members to trap the other member in place.

23. A method according to claim 22, wherein the further member is initially cupped and has a central portion extending along the axis of the inner member member, this central portion being deformed to a condition in which it traps the outer race member in place encircling the bearings.

24. A method according to claim 22 or 23, where the outer race member is completely completely encircled by outer portions of the further member, the outer portions being bent to form a mount for location in a roller tube.

25. A method according to any one of claims 18 to 21, wherein the inner race is passed through a hole in an outer race member, ball bearings are located in the outer race member around the periphery of the inner race member, a mount member is placed over the inner and outer race members, and the mount member and outer race member are deformed to form the outer race and a mount for a conveyor tube while trapping the bearings in the groove in the inner race member.

26. A method substantially as herein described with reference to the accompanying drawings.

27. A roller assembly substantially as herein described with reference to the accompanying drawings.