GB2242146A

GB2242146A - Work clamping ring

Info

Publication number: GB2242146A
Application number: GB9100001A
Authority: GB
Inventors: Alfred Weidinger
Original assignee: SKF GmbH
Current assignee: SKF GmbH
Priority date: 1990-03-22
Filing date: 1991-01-02
Publication date: 1991-09-25
Anticipated expiration: 2011-01-02
Also published as: GB9027970D0; DE4009171A1; GB2242146B; FR2659883A1; GB9100001D0

Abstract

For clamping tubular intermediate products for rolling bearing cages, a clamping ring (1) is hold within a multi-saw chuck. It accommodates the intermediate product (2), for example a thin-gauge portion of tube, so that pockets (5) for rolling bodies (6) can be machined into it by turning, milling, stamping etc. Corresponding locations on the clamping ring (1) have recesses (7) which accommodate the portion of the machining tool which projects during machining. The advantages of the ring are a firm hold, stable radial support and precise working results. <IMAGE>

Description

1 1 -4::> 1-,4 is A DEVICE FOR CLAMPING TUBULAR ELEMENTS The invention

relates to a device for clamping a tubular element during manufacture of a rolling bearing cage therefrom.

DE-PS 585.833 discloses a clamping device for clamping portions of a tube which employs a clamping ring. Radial forces emanating from radially acting clamping members result in an even clamping of the tube portion over its entire periphery. In consequence, very thin-gauge tube portions can be machined. However, machining is only possible as far as the cylindrical clamping face of the clamping ring or, as known, on the portion protruding from the clamping device. If it is intended to machine recesses which extend through the side wall of the tube portion, the prior art device cannot be used.

The object of the invention is to provide a device of the type mentioned at the outset, for clamping purposes and which permits a machining of through-pockets into tubular intermediate products to provide rolling bearing cages.

According to the present invention there is provided a device for clamping a tubular element during manufacture of a rolling bearing cage therefrom, the device comprising a multi-jaw chuck and a clamping ring which, in use, is disposed between jaws of the chuck and the tubular element, wherein radially extending recesses are formed in a radially inner side of the clamping ring, the distribution of the recesses corresponding to the distribution of pockets to be formed in the finished cage and each recess being such as to accommodate an end portion of a tool used in forming the recess.

To produce a rolling bearing cage, it is necessary to machine 11, into a tubular element for example a plurality of rectangular continuous pockets distributed evenly over the periphery. The clamping ring in a preferred embodiment of the invention has for this purpose and at corresponding locations recesses which permit of adequate insertion of the machining tool. The recesses are sufficiently large that there is no possibility of the tool being damaged but on the other hand a sufficiently firm and distortion-free clamping of the tubular element is guaranteed while at the same time it is provided with stable radial support against the action of the tool. In this way, highly accurate pocket dimensions and an outstanding quality of the boundary faces can be produced.

After insertion of the substantially cylindrical element, which consists for example of sheet metal, into the clamping ring, the latter is clamped radially in for instance a three-jawed chuck. In known manner, the radial forces are distributed relatively evenly over the periphery of the element. Suitably, a step-wise onwards rotation of the device is preestablished in known manner by a suitable control and synchronising arrangement. Thus, the pockets can be machined precisely at those locations in the recesses which are now masked by the tubular element.

For machining, working procedures such as drilling, milling, stamping etc. are suitable. Also a relative feed movement of the tool in a radial, axial and/or peripheral direction can be envisaged. Furthermore, it is also advantageous to apply a known method in which, while the workpiece is rotating, a turning tool travels through a cycloidal path synchronised therewith.

i 1 1 The invention will now be described, by way of example. with reference to the accompanying drawing, which is a transverse section of a device according to the invention.

The single figure of the drawing shows a partial radial section through a device for clamping a tubular element during manufacture of a roller cage therefrom. The device includes a clamping ring with recesses, trough-like rounded profile recesses being shown at the locations A to E while recesses with radially extending peripheral faces are shown at the locations F to 1.

The clamping ring 1 shown in Fig. 1 serves to clamp radially a tubular element 2 for a roller cage and is inserted in a commercially available six-jawed chuck of which only the radially adjustable jaws 3 are shown. The clamping ring 1 is relatively thick-walled, is provided at one place with a radial slot 4, and comprises radial recesses 7 corresponding to the pitch of the rollers 6 which are to be inserted into the pockets 5 of the cage. They serve to accommodate that portion of a machining tool, not shown, which protrudes after machining.

The pockets 5 at locations A to E are. as shown at the location E, constructed for rollers 6. The guide^faces 8 are adapted to the shape of the rollers. The said pockets 5 are therefore produced with a milling or turning tool which in addition to the rotating movement also performs a radial feed movement. The profile of the trough-shaped recesses 7 is in fact so chosen that the cutting edges of the tool do not come in contact with the material of the clamping ring 1 and ye t a stable radial bracing of the intermediate product 2 is guaranteed. At the locations A, D and E, the pockets 5 are already machined. At A, the trough-shaped recess 7 and the guide faces 8 are supplemented by the peripheral line of the roller 6. At B, the pocket 5 is as yet not machined into the product. At C, there is a trough-shaped recess 7 which has a slightly larger radius than the roller 6 and the pocket 5 in order reliably to avoid the machining tool coming in contact with the clamping ring 1.

At locations F to I, there are recesses 7 having substantially radially extending peripheral surfaces 9. This shape is particularly suitable for the use of stamping tools which are substantially radially acting, are constructed to be small for example in comparison with the pocket 5 and which are guided under programmed control along the boundary line 8 of the pocket 5. This machining is particularly suitable for very thin-gauge sheet metal cages. Also here, the angle of inclination of the guide faces 8 for the roller 6 may be adapted to the shape of the roller but may be other than illustrated. In the stamping process, the peripheral edges of the recesses 7 act as a cutting edge 10. For this reason, the clamping ring 1 is of correspondingly hard construction.

At location B, the clamping ring 1 comprises a radial slot 4 so that during clamping by the jaws 3 it can be adapted within close limits to the diameter-of the intermediate product 2.

The device according to the invention is suitable for virtually all types of cages, in other words also for balls, self-aligning roller bearings etc. The recesses 7 are adapted to the rolling bodies regardless of the machining process. In all cases, a stable support for machining is achieved at all locations on the intermediate product 2.

Claims

CLAIMS:

1. A device for clamping a tubular element (2) during manufacture of a rolling bearing cage therefrom, the device comprising a multi-jaw chuck and a clamping ring (1) which, in use, is disposed between jaws (3) of the chuck and the tubular element (2), wherein radially extending recesses (7) are formed in a radially inner side of the clamping ring (1), the distribution of the recesses (7) corresponding to.the distribution of pockets (5) to be formed in the finished cage and each recess (7) being such as to accommodate an end portion of a tool used in forming the recess.

2. A device as claimed in Claim 1, wherein each of the recesses (7) extends only part of the way through the clamping ring (1).

3. A device as claimed in Claim 1 or 2, wherein each recess (7) is partspherical in shape.

4. A device as claimed in any one of the preceding claims, wherein each recess (7) has radially extending peripheral faces (g).

5. A device as claimed in any one of the preceding claims, wherein edges of the peripheral faces (9) of each recess are constructed as cutting edges (10).

1

6. A device as claimed in any one of the preceding claims, wherein the clamping ring (1) is radially slotted, thereby to provide a variable radius.

7. A clamping ring which, during manufacture of a rolling bearing cage from a tubular element, is disposed between the said element and the jaws of a multi-jaw chuck, wherein radially extending recesses (7) are formed in a radially inner side of the clamping ring, the distribution of the recesses (7) corresponding to the distribution of pockets (5) to be formed in the finished cage, and each -recess (7) being such as to accommodate an end portion of a tool used in forming the recess.

8. A device for clamping a tubular element, the device being constructed, arranged and adapted to operate substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawing.

1 Published 199 1 at The Patent OEI,-. Concept House. Cardiff Road Sal., Branch in! 6 h, 1 nial. be obtained from 2 e Paint. -11e117)071- Gwent NP9 I PH Sz Mary Cray. Kent h Cross Kevs. N, urther copies ""Port. NPI 7HZ. Printed by,tchr 'Ird Iqjes