DE2212512B1 - Post-deformation of internal gears to create locking gears - Google Patents

Description

In order to avoid an automatic loosening of meshed gears, various Deformations of the tooth flanks locking gears created. This requirement also arises with the sliding internally toothed sleeves in manual transmissions to avoid a so-called »gear failure« to avoid. To do this, the tooth flanks are inclined towards the center of the sleeve of both Sides by weakening. This elongated bevel then forms the locking teeth.

This deformation of the tooth flanks was usually caused by metal cutting, such as back planing or relief grinding. Rolling processes are also known. These but are only suitable for sleeves with a larger diameter. Special machines are also required and the operations are complex.

As far as purely external gearing is concerned, there has been a significant improvement in the Manufacturing already found. According to a known method (German patent specification 2 040 413) Teeth or tooth-like projections of a relatively complicated shape on the outer circumference of a ring or the like. by radial pressing in the course of plastic cold deformation from an annular extension formed and then recalibrated according to the requirements. This procedure brings Although considerable advantages over the previous method of production, but can be due to the individual Do not use steps for recalibrating an internal gear.

But now is also on hand of a device for forging strips, in particular Brake bands, known, by a radial cold deformation acting on the inner circumference of the ring body (U.S. Patent 2,711,659). In this known spreader are by an inner mandrel segment-like expansion elements, which are pretensioned by springs in the starting position are pressed against the inner surface of the belt so that it is pressed radially against a fixed outer ring will.

Although there is a special need for the simplification of the post-deformation of internal gears during production existed, it was not recognized that this known spreading device was redesigned the expansion elements can be used for this purpose.

The task of significantly simplifying the post-deformation of the internal toothing of a sleeve and to improve the quality of the execution considerably, is now achieved by according to the invention the use of an expanding device with an inner mandrel and expanding elements that are inserted into the Initial position are pretensioned, and with which it is pressed radially against a fixed outer ring, on the Cold re-pressing of the internal toothing of a sleeve to the locking toothing, the expansion elements the Have the negative shape of the locking teeth.

By using this spreader

ίο with the modified expansion elements, it is possible to use any shape of tooth flanks in the simplest possible way Way to manufacture by post-deformation. No complicated machines are required. at Changes to the tooth flanks only require the exchange of the expansion elements. So are also to significantly reduce manufacturing times and manufacturing costs.

An embodiment of the use of the spreading device in pursuit of the invention is described with reference to the drawing. It shows
F i g. 1 a section through the device,
F i g. 2 shows a plan view of the tooth flanks after the locking teeth,

F i g. 3 possible forms of locking teeth and F i g. 4 is a plan view of an embodiment of the Spreading elements.

A base 2 is mounted on a base plate 1, on which expansion elements 3 are radially displaceable are. They are spread by a central conical inner mandrel 4, which is supported by a pressure piece 5 is pushed in. A sleeve 6 to be deformed in its internal toothing is inserted and is supported on the outside of a support ring 7. It rests on an ejector ring 9, which is secured by an ejector pin 10 is actuatable.

The expansion elements 3 are each provided with a groove on their end faces, in the removable annular groove Coil springs 8 are inserted. These springs 8 tension the expansion elements in the starting position against each other and place them on the inner mandrel.

When the pressure piece 5 is pressed down, the inner mandrel is inserted into the conical interior of the expansion elements pressed in and spreads them radially apart against the sleeve 6. The teeth on the expansion elements put on the teeth of the sleeve 6 and deform them in the desired way.

The spreading elements 3 are expediently as a coherent ring part on conventional machines made by grinding, etc. The shape of their teeth corresponds to the shape of the gaps in their teeth desired locking teeth. The division into the required segments is then done by cutting.

With the use of the spreading device in the sense of the invention, the most varied forms of locking teeth can be created in accordance with the design requirements. Some shapes are shown in FIG. 3 shown. The most common shape is that of FIG. 2. The undercut angle resulting from the post-deformation is denoted by x.

When cold re-pressing, the excess material is in the usual way in the tooth root and the Tooth head printed. A low ridge is created in the tooth root, by which the tooth root clearance is increased got to.

1 sheet of drawings

Claims (1)

Claim: Use of an expansion device with an internal mandrel and expansion elements that are attached via springs in the initial position are biased, and with the radially pressed against a fixed outer ring is, on the cold re-pressing of the internal teeth of a sleeve to the locking teeth, the Spreading elements have the negative shape of the locking teeth.