FR2474267A1 - Induction heater for bearing races on shaft - has two section laminated square cross-section rods of non-magnetic material which are used as mounting elements - Google Patents

Abstract

The device provides induction heating required during fitting of races on an axle, allowing expansion followed by cooling to ensure a tight fit. The arrangement ensures that the heating is correctly distributed, is in the region required and takes a minimum of time and energy. The bearing race (5) is fitted on its shaft (3) which is itself attached to a rectangular section rod made up of stacked laminations of some non-magnetic material soldered together. The shaft, similarly laminated, is inserted into a hole (4) in a similar laminated rod on the opposite side of the bearings. The laminated rods typically have 30mm sides with an overall length of 250mm. The centre shaft would have an 8mm diagonal and 80mm length. The device can rest on wing sections of a transformer frame to close the frame. The device provides an important time saving in the heating of race bearings and allows precise focussing of magnetic flux lines.

Description

the present invention relates to the field of mechanical industry, in particular the mounting of various bearings on axes, and relates to a device for the induction heating of bearings.

 The mounting of the bearings on axes with tight adjustment s1 is generally carried out by heating the said bearings beforehand so as to obtain a slight expansion, then by sliding them on the axes, the cooling of the bearings causing their tightening on the said axes.

Currently, the bearings are heated, either by the flame of a torch, or by induction. In the latter case, the bearing is placed on a conductive bar forming a wing of a transformer frame, and constitutes the single turn of the secondary of this transformer.

 Heating with a torch flame does not allow good heating accuracy and even distribution of the latter, and in the case of special bearings, for example sealed, there is a risk of degradation thereof .

 Induction heating allows a uniform temperature distribution throughout the bearing. However, such a heating method requires a relatively long time and a significant expenditure of energy. In addition, a large number of bars of different dimensions is necessary to cover a large range of bore inner ring bearings.

 The present invention aims to overcome these drawbacks.

 It relates, in fact, to a device for the induction heating of bearings, characterized in that it essentially consists of a rod made of two elements connected to each other by fitting one of the elements onto a rod, of smaller section, integral with one end of the other element, all these bars being constituted by a stack of thin sheets for dynamo, non-magnetic and welded together.

 The invention will be better understood from the description below, which relates to a preferred embodiment, given by way of nonlimiting example, and explained with reference to the appended schematic drawing, the single figure of which is a view in longitudinal section of a device according to the invention carrying a bearing.

the device for the induction heating of bearings, shown in the appended drawing, is constituted by a bar in two elements 1 and 2 connected together by a bar 3 of smaller section, penetrating into the end of the element 2 and integral of one end of element 1.

elements 1 and 2 as well as the bar 3 are advantageously constituted by a stack of thin sheets for dynamo, non-magnetic and welded together. The bars thus obtained preferably have a square section. the bar 3, of smaller section, is secured to one end of the element 1, for example by welding, and enters a bore 4 of the element 2.

 elements 1 and 2 may have, for example, a section of 30 mm x 30 mm for a total length of 250 mm, while the bar 3 also has a square section whose diagonal measures 8 mm, and its length is 80 mm.

With a device thus constituted, resting by its two ends on the wings of a transformer frame to close this frame, it is possible to heat bearings whose bores of the inner rings range from 8 mm to 40 mm, the bearing 5 being mounted on the bar 3 between elements 1 and 2. The dimensions of the various elements indicated above are not, however, limiting, and larger sections are possible for heating larger bearings.

Thanks to the invention, it is possible to achieve a significant gain in time over the heating time of a bearing, compared with known devices, and thus, considerably increase the yield. In addition, the device according to the invention makes it possible to concentrate the magnetic flux at the precise place where the bearing is placed, that is to say between the ends facing one another of the elements 1 and 2. .

 Of course, the invention is not limited to the embodiment described and shown in the accompanying drawing. Modifications remain possible, in particular from the point of view of the constitution of the various elements, or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention.

Claims (2)

- REVEN i C A T ION S-  1. Device for the induction heating of the bearings, characterized in that it is essentially constituted by a bar in two elements (1 and 2) connected together by fitting Trun elements (2) on a bar (3), of smaller section, integral with one end of the other element (1), all these bars being constituted by a stack of thin plates for dynamo, non-magnetic and welded together. 2. Device according to claim 1, characterized in that the bearing to be heated (5) is mounted on the bar (3) of smaller section between the elements (1 and 2) of the other bar.