GB2233403A

GB2233403A - Roller bearing cage

Info

Publication number: GB2233403A
Application number: GB9013611A
Authority: GB
Inventors: Harald Bitsch; Otto Oldewurtel; Klaus Juergen Winter
Original assignee: Mannesmann AG
Current assignee: Vodafone GmbH
Priority date: 1989-06-21
Filing date: 1990-06-19
Publication date: 1991-01-09
Also published as: DE3920689A1; IT1248953B; IT9020625A0; JPH0333509A; GB9013611D0; FR2648879A1; IT9020625A1

Abstract

The cage of a roller bearing is split transversely to the circumferential direction into segments and is formed with longitudinal beads (3) and crossbars (4) for rollers. The beads (3) have longitudinal bores (7) at the junction points for pins (8) which are inserted in these bores. The bearing is useful in particular for supporting a hoisting drum on a gearbox between projecting thrust races for guiding the cage. <IMAGE>

Description

L3.4 0;13 1 Bearing Cage for a Roller Bearing The invention relates to

roller bearings and particularly tp,,a cage for retaining rollers therein.

Such bearings are used for example to support hoisting apparatus on a gearbox. In such bearings, the case is typically split transversely to the circumferential direction, and such a split cage is known from the German Gebrauchsmuster No. 88 08 271, which is placed in a roller bearing groove of a gearbox of hoisting apparatus, the groove being defined by thrust races for the roller bearing.

In the device of Gebrauchsmuster No. 80 08 271, the segments of the cage are held together by clamps, which are pushed over crossbars at the segment ends. This arrangement torms a non-rigid connection at the junction points. The clamps can bend open because they are only able to transmit weak bending moments. Thus, the cage may deform during continuous operation due to the bearing heating up, rub against the inner race and possibly get caught. There would then be a risk of obs.truction and the bearing being destroyed.

The present invention addresses the above problems and seeks to provide a more rigid cage assembly.

According to the invention, a bearing cage is provided for a roller bearing defining a rotational axis. The cage comprises circumferential beads with crossbars extending between the beads for supporting rollers between the adjacent crossbars, the cage being split transversely relative to the rotational axis into a plurality of segments, adjacent segments being secured by circumferentially extending pins received in bores formed in ends of the beads. The cage normally comprises at least three segments, and it is preferably serrated pins or roll pins which are pressed into the bores to render-the split cage highly rigid in the radial direction due to their large spacing.

When the roller bearings are relatively large, e.g.

2 with diameters exceeding 150 mm, the cage is preferably formed from three segments. The crossbars will normally have guide surfaces and snap catches for the cylindrical rollers, which.are,placed in the segments at the sub5 assembly stage.

The guide surfaces and snap catches need not extend over the entire length of the rollers, but can only cover the end areas of the latter, so as not to wipe or scrape off lubricant film in the area of maximum pressure between the rollers and the thrust race. The radius of curvature at the guide surfaces and snap catches is typically greater than the radius of the rollers, thus enabling the latter to move in the radial direction of the roller bearing (e.g. to accommodate out-of-roundness at the running surface of the gearbox).

The cage' may be made of a fibre-reinforced plastics material which does not deform under heavy loads and keeps the rollers on the track. The inner race may be a gearbox which is made of grey cast iron and reinforced in the roller bearing area. A thrust race of the roller bearing normally bears a seal which lies atjainst the hoisting drum or other apparatus supported on the bearing.

When the bearing is placed in a hoisting apparatus, which could drop its load if damage occurs, additional safety is usually provided by gearbox reinforcement under the roller bearing area, together with the thrust race. Even total failure of the bearing should not result in the gearbox being crushed or severed.

In a preferred embodiment of the invention a spring- hard, rolled, open race is inserted between the inner race of the bearing and the rollers, which race is Vshaped at its junction point. The two ends of the junction point are provided with chamfers in order to prevent roller contact. Owing to the inexpensive, spring-hard race, the service life of the bearing is longer than it would be if the rollers were to run directly on the grey cast iron gearbox.

An embodiment of the invention will now be described 3 by way of example and with reference to the accompanying drawings wherein:

Figure 1 is a side view of the segment of a roller 5 bearing embodying the invention; Figure 2 is a plan view of the segment of Figure 1; Figure 3 is an enlarged section taken on the line III-III of Figure 2; Figure 4 is a section taken on line IV-IV of Figure 3; Figure 5 shows the ends of two roller bearing segments; Figure 6 is a plan view of the parts shown in Figure 5; Figure 7 is a circumferential section through a bearing of the invention mounted on a gearbox housing; Figure 8 is an enlarged view of the junction point of the open race shown in Figure 7; Figure 9 is a section taken on line IX-IX of Figure 8.

In a roller bearing embodying the invention the rollers 1 which can be seen in the drawings are arranged in a cage 2, the longitudinal beads 3 of which are connected together by crossbars 4. The crossbars provide at their ends surfaces 5 for guiding the rollers 1 and snap catches 6, which yield when the rollers 1 are inserted. As indicated by dot-dash lines in Figure 3, the rollers 1 are smaller than their mounting space between the guide surfaces 5 and the snap catches 6. Figures 5 and 6 show that the segments comprise longitudinal bores, cut in the end faces of the longitudinal beads 3 at the junction points, for pins 8, which are to be firmly inserted and are in the form of serrated pins or roll pins.

Figure 7 shows the arrangement of the rollers 1 between the longitudinal beads 3 of the cage between the thrust races 14 and 14a of a gearbox 12, which is 4 specially reinforced in the area of the roller bearing. A hard steel race 9 is inserted in the roller bearing groove 13, the junction point 10 of which face is Vshaped and provided with chamfers 11, as shown in Figures 5 8 and 9.

The rollers 1 bear the end of a hoisting drum 15, which is made of hightensile steel, and are protected against dirt by seals 16, one of which is arranged between the thrust race 14 and the hoisting drum 15 and the other between the hoisting drum 15 and the flange of the gearbox 12, which is borne by a support frame 17.

Claims

1. A bearing cage for a roller bearing defining a rotational axis, which cage comprises circumferential beads with crossbars extending between the beads for supporting rollers between the adjacent crossbars, the cage being split transversely relative to the rotational axis into a plurality of segments, adjacent segments being secured by circumferentially extending pins received in bores formed in ends of the beads.

2. A bearing cage according to claim 1 including at least three said segments.

3. A bearing cage according to Claim 1 or Claim 2 wherein the crossbars have guide surfaces and snap catches for retaining cylindrical rollers.

4. A bearing cage according to Claim 3 wherein two guide surfaces and two snap catches are arranged spaced from each other on each crossbar.

5. A bearing cage according to Claim 3 or Claim 4 wherein the diameter of curvature of the guide surfaces is greater than the diameter of the rollers, and the spacing between the tips of the snap catches, which are open towards the outer curve of the roller bearing, is smaller than the diameter of the rollers. 25

6. A bearing cage according to any preceding Claim made of a fibre-reinforced plastics material.

7. A bearing cage for a roller bearing substantially as described herein with reference to the accompanying drawings. 30

8. A gearbox having a roller bearing including a cage according to any preceding claim mounted between thrust races on the body of the gearbox.

9. A gearbox according to Claim 8 wherein the inner race of the bearing is also formed on the gearbox body, which body is made of grey cast iron.

10. A gearbox according to Claim 8 or Claim 9 wherein the gearbox is reinforced in the roller bearing area.

6

11. A gearbox according to any of Claims 8 to 10 wherein one of the thrust races has a seal which lies against an outer race of the bearing.

12. A gearbox according to Claim 11 wherein said 5 outer race is part of a hoisting drum.

13. A gearbox according to any of Claims 8 to 12 wherein a spring-hard, rolled race is inserted between the inner race of the bearing and the rollers.

14. A gearbox according to Claim 13 wherein the 10 rolled race is open at a V-shaped junction point.

15. A gearbox according to Claim 14 wherein the side of the rolled race which faces the rollers is formed with chamfers at the junction point.

Published 1991 at The Patent Office. State House. 66171 High Holborn. Ld)ndon WC1R 47P. Further copies may be obtained frorn The Patent Office. $a]- Branch. St Mary Cray. Orpington. Kent BR5 3RD. Printed by Multiplex techniques lid. St Mary Cray. Kent. Con. 1187