GB817744A - Improvements relating to cages for roller and ball bearings - Google Patents

Abstract

817,744. Moulding cages for bearings. BRITISH TIMKEN Ltd. Sept. 30, 1957 Dec. 13, 1956, No. 38034/56. Class 87(2). [Also in Group XXXIV] A cage for ball or roller bearings comprises end rings 1, 2, Fig. 3, connected by bars 3, and pockets 4 between the bars, the pockets being formed during moulding (e.g. by injection) by cooperating inwardly and outwardly projecting core parts on outer and inner mould members respectively, the inner diameter of one end ring being equal to or greater than the outer diameter of the other end ring. The cage may be made of nylon, that in Fig. 3 being for tapered roller bearings. Figs. 7, 8 show a mould for making this cage, comprising inner and outer members 8, 9 and a stripper ring 10 slidably mounted on the member 8 and/or on dowel pins carried by the member 8. The mould member 9 has a conical recess 12 with a series of circumferentially spaced core projections 13 separated by narrow slots which produce narrow central ribs 6, Fig. 3, on the cage bars 3. The projections 13 have faces which are parallel to and concentric with the axis of the mould and intersect the conical surface of the mould member at points either intermediate the width thereof (as shown) or adjacent the inner end thereof, according to whether the interior diameter of ring 2 is to be greater than or equal to the exterior diameter of ring 1. The main part of ring 2 is formed within an annular space 15, the remainder being formed by the mould member 8 and stripper ring 10. The mould member 8 has a spigot 16 which is cylindrical at 17 with a conical extension 18 having projections 19 spaced by slots for forming the main portions of the cage bars 3. The projections 19 mate and cooperate with the projections 13 and with the conical surface of the recess 12, leaving an annular space 22 for the formation of the ring 1. This space 22 communicates through restricted radial passages 24, Fig. 7, with a circular cavity 23 formed between recessed portions of the mould members 8, 9. The cavity 23 is in communication with axial passages 25, 26 in mould members 9, 8. During moulding, the mould members are correctly located by dowel pins 11 and held together by bolts 28 or by the platens of an injection moulding machine. Plastic material is injected through the passage 25. After moulding, the inner member 8 and the moulded cage are removed from the member 9, the cage being held by a sprue puller 29 formed in an undercut enlargement 31 of the passage 26. The stripper ring 10 and a sprue ejector rod 32 are then moved axially to strip the cage from mould member 9. A central web 30 which has been formed in the cavity 23 is then removed to leave the finished cage. Fig. 17 shows part of a mould for producing a cage for cylindrical roller bearings, Fig. 16, the inner diameter of the ring 2<SP>1</SP> being equal to the outer diameter of the ring 1<SP>1</SP>. The recess 12<SP>1</SP> and spigot extension 16<SP>1</SP> are cylindrical instead of conical, and are provided with rectangular section projections 13<SP>1</SP>, 19<SP>1</SP>. In a further modification, Figs. 18-23, the cages are for ball bearings and the inner portions of the end rings are formed with part-spherical ball engaging and retaining surfaces. Fig. 24 shows a mould for use where the conical cage of a tapered roller bearing is steeply inclined to the axis of the bearing, the joint 21111 between the core parts 13<SP>111</SP> and 19111 on the outer and inner members 9<SP>111</SP> and 8111 respectively being inclined to the axis. The spaces between adjacent core parts 19<SP>111</SP> may contain V-shaped core parts to form grooves in the inner edges of the cage bars as seen in Fig. 25 (not shown).