DD235576A1 - DEVICE FOR COLD ROLLING OF INTERNALLY PROFILED RINGS WITH TANGENTIAL EXPANSION - Google Patents

Abstract

The invention relates to a device for cold rolling internally profiled rings with tangential expansion, in which during the entire rolling process by Dornhuelsen on the rolling mandrel whose axial movement is formschlüssig with the radial feed movement of the work roll by appropriately designed Gleitflaechen, an additional axial compressive stress directly in the forming zone the ring is applied. As a result, due to the process of internal profiling and simultaneous rolling of rings, z. B. ball bearing outer rings, resulting uniaxial tensile state avoided in the ring and thus eliminates the cause of the occurrence of cracks in the ring bore. Furthermore, the field of application of cold forming with high manufacturing reliability and low rejection rate is extended to internally profiled rings. figure

Description

For this 1 page drawing

Field of application of the invention

The invention relates to a device for cold rolling internally profiled rings with tangential expansion under significant diameter increase during profiling and can be used primarily in the rolling bearing industry for the production of rolling bearing outer rings.

Characteristic of the known technical solutions

"During tangential expansion of internally profiled rings, during cold rolling in the first phase only the raised points of the profile of the rolling mandrel contact the ring and cause a local increase in diameter.The inner surfaces of the ring not acted upon by the rolling mandrel are thus subject to a uniaxial tangential tension, which causes the Formation of cracks within these zones favors the inner ring surfaces.

Known rigid lateral mandrel profile surfaces for additional application of axial compressive stresses in the forming lead Night zurh success, since the ring tends to the outer diameter to the width and the inner diameter of a collection of side surfaces, which can lead to detachment of the annular edge of the tool profile surface.

Known is a tool assembly according to DE-OS 1652657, which allows an additional axial forming. However, this axial compression takes place only after the radial forming, so that no axial effects on the stress state during radial rolling arise.

According to DE-OS 2504969 a solution for cold rolling with various types of face rolls for axial deformation is known. Due to the arrangement of the front rollers outside the deformation zone for the radial expansion, the axial stress state during the radial rolling can likewise not be directly influenced.

Also known is an apparatus for cold rolling with end-side rollers directly to the radial forming zone (DE-OS 2319811). However, the axial action of these rolls is limited by the work roll. In the axial retraction of the ring described above, no additional axial pressure builds up.

It is also a device for cold rolling of rings known (DE-PS 1184726), in which additional sleeves, acted upon by spring force, are mounted on the mandrel, which engage axially on the workpiece. Upon continuation of the rolling process, however, these sleeves are moved axially outwardly by the tool design, so that likewise no defined axial compressive stress is exerted on the ring.

Object of the invention

It is the object of the invention to eliminate the mentioned disadvantages of the known solutions, that is to say the cause of the cracking when profiling inner annular surfaces, e.g. Wälzlageraußenringen, with further increase in manufacturing safety, considerable material savings and expansion of the field of application.

Explanation of the essence of the invention

The object of the invention is to provide an automatically operating device, which by a certain arrangement and design of the tool elements the possibility of additional axial pressure build-up in the forming zone during the radial cold forming of innenprofilie.rten rings with tangential expansion, eg.

Rolling bearing outer rings realized.

Two mounted on a mandrel, axially displaceable mandrel sleeves between which the ring to be rolled, are by positive engagement with the work roll in contact. During the advancing movement of the roller, the mandrel sleeves are moved according to the choice of the angle of the positive locking wedge-shaped slip planes on the ring and practice with penetration of Walzdomprofiles in the ring an axially acting pressure force on the ring.

The initially not acted upon by the roll mandrel ring inner surfaces of the forming zones are thus not only subject to the tangentiälen caused by the expansion, but also an additional axial compressive stress.

This state of tension prevents tearing of the free inner ring surfaces during rolling.

After the solution according to the invention internally profiled rings can be produced with high manufacturing reliability crack-free by cold forming, thus realizing a significant material savings and expansion of the field of application.

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embodiment

The invention will be explained in more detail below using the exemplary embodiment of an automatically operating device for cold rolling internally profiled rings with tangential expansion under significant increase in diameter on the example of a ball bearing outer ring.

The accompanying drawing shows a sectional view of the device at the beginning and end of the rolling process.

The device consists of a rolling mandrel 3, which for example carries the profile of a ball bearing outer ring 1. On each side of the profile is an axially movable mandrel sleeve 4 with snap ring 8 and conical end face 5 and inner surface. 6

Assigned to the rolling mandrel 3 is a right angle to this movable work roll 2 with a receiving profile for the ball bearing outer ring 1 and a Innenprofilierung7 as a negative to the end face. 5

The inserted for rolling ball bearing outer ring 1 has a slightly greater width than in the finish-rolled state. The inner surfaces 6 der.beiden two sleeves 4 detect the ball bearing outer ring 1 with the beginning of rolling and center it to the rolling mandrel profile.

With insertion of the feed of the work roll 2, the two mandrel sleeves 4 are detected by the inner profiling 7 at the end faces 5 and axially moved by the trained slip plane corresponding to the selected angle inwards.

This creates a constant additional compressive stress directly in the forming zone at the inner ring diameter, which prevents the tearing of the material.

Claims (1)

- Ί - ΙΗΌ O / Invention claim: Apparatus for cold rolling internally profiled rings mittangentialer widening of substantial diameter increase during profiling, consisting of a work roll and a mandrel with rolled profile and axially movable mandrel sleeves, characterized in that for the axial movement of the mandrel sleeves (4) on the rolling mandrel (3) for establishing an axial compressive stress state in the forming zone continuous positive engagement by wedge-shaped slip planes between the work roll (2) and mandrel sleeves (4), including the mandrel sleeves (4) each have a conical end face (5) and the work roll (2) as a negative to each corresponding inner profile (7) has.