METHOD FOR PRODUCING A SHORT CIRCUIT ROTOR AND SHORT CIRCUIT ROTOR

Abstract

A method for producing a short circuit rotor, by providing a laminated rotor core with through openings for shorting bars of a squirrel cage as well as providing the shorting bars; inserting of the shorting bars into the through openings such that an axial overhang remains on both sides; placing a main disk with through openings on both sides for the shorting bars, whose axial length corresponds to the overhang, as well as an edge disk immediately adjacent to the main disk and the ends of the shorting bars. The main disk and the edge disk form a shorting ring of the squirrel cage, and the main disk and the edge disk are welded by radially encircling electron beam welding.

Claims

1. A method for producing a short circuit rotor, comprising: providing a laminated rotor core with through openings for shorting bars of a squirrel cage as well as providing the shorting bars, inserting the shorting bars into the through openings such that an axial overhang remains on both sides, placing a main disk with through openings on both sides for the shorting bars, whose axial length corresponds to the overhang, as well as a continuous edge disk immediately adjacent to the main disk and the ends of the shorting bars, wherein the main disk and the edge disk form a shorting ring of the squirrel cage, welding the main disk and the edge disk by means of radially encircling electron beam welding.

2. The method according to claim 1, wherein the short circuit rotor is axially compressed prior to the welding of the main disk and the edge disk so that the ends of the shorting bars lie against the edge disk with material bonding.

3. The method according to claim 1, wherein after the welding, a clamping ring is placed each time around a pair composed of main disk and edge disk and tightened.

4. The method according to claim 1, wherein the through openings of the main disk are punched out.

5. A short circuit rotor, produced according to a method according to claim 1, comprising a laminated rotor core and a squirrel cage with shorting bars extending through continuous openings in the laminated rotor core and shorting rings which axially short-circuit the shorting bars on both sides, wherein each shorting ring comprises a main disk with through openings, through which the shorting bars extend and project out from the laminated rotor core, especially in form fitting-manner, and an edge disk following the main disk immediately on the axially outer side, against which the shorting bars lie in materially-bonded manner, hereby characterized in that the edge disk and the main disk are radially welded together by electron beam welding.

6. The short circuit rotor according to claim 5, wherein the edge disk and/or the main disk are composed of copper and/or aluminum and/or an alloy comprising copper and/or aluminum, and/or in that the edge disk is composed of a higher-strength material than the main disk.

7. The short circuit rotor according to claim 5, wherein in the case when the main disk and edge disk are not composed of a higher-strength alloy and/or are composed of the same materials, the shorting ring is radially surrounded by a clamping ring.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0027] Further benefits and details of the present invention will emerge from the exemplary embodiments described in the following, as well as based on the drawing. Shown here:

[0028] FIG. 1 an exploded drawing of one side of a short circuit rotor according to the invention,

[0029] FIG. 2 a perspective view of the side of the joined short circuit rotor according to the invention, and

[0030] FIG. 3 a cross-sectional view of the side of the short circuit rotor according to the invention.

DETAILED DESCRIPTION OF THE FIGURES

[0031] FIG. 1 shows basic components of one side of a short circuit rotor 1 according to the invention in an exploded view, the axially opposite side of the short circuit rotor 1, which is not shown, being a mirror image. The short circuit rotor 1 comprises, prior to the joining of its components shown here, a laminated rotor core 2, such as is basically known in the prior art. The laminated rotor core 2 has through openings, in which the shorting bars 3 of a squirrel cage of the short circuit rotor 1 are already inserted here. The shorting bars 3 stick out axially on both sides, so as to be able to engage with a form fit in through openings or cavities 4 of a main disk 5. The axial closure of the short circuit rotor 1 is formed by an edge disk 6, having no cavities or openings of any kind for the shorting bars 3, since it should lie against the latter with material bonding. The main disk 5 and the edge disk 6 form the shorting ring 7 of the squirrel cage.

[0032] In order to fabricate the short circuit rotor 1, the components shown in the exploded view are assembled together axially and compressed by means of a clamping device, so that not only does the main disk 5 lie against the edge disk 6 with material bonding, but also the shorting bars 3 lie against the edge disk 6 with material bonding. Being thus prestressed by the clamping device in this way, a radial electron beam welding is then carried out in order to join the main disk 5 to the edge disk 6. A perspective view of the short circuit rotor 1 thus joined in only a single step is shown in FIG. 2. Also indicated there is the weld 8 between the main disk 5 and the edge disk 6, the electron beam welding also extending to a connecting of the shorting bars 3 to the edge disk 6.

[0033] This is clearly recognizable in the cross-sectional view of the joined short circuit rotor 1 in FIG. 3, since the weld 8 also extends beyond the shorting bars 3.

[0034] In the present exemplary embodiment, the main disk 5 is chosen to be thinner than the edge disk 6, so that the through openings 4 of the main disk 5 can be punched out. An embodiment is also conceivable in which the main disk 5 is thicker than the edge disk 6, in order to create a greater distance from the laminated stack 2 during the welding.

[0035] Optionally, a clamping ring 9 as indicated in FIG. 3 may also extend radially about the shorting ring 7. The use of such a clamping ring 9 proves to be especially advantageous when a higher torsional strength is required than is provided by the configuration of the disks 5, 6, for example when the disks 5, 6 both are not composed of a higher-strength material, or, for example, when they are formed as simple copper and/or aluminum disks. The clamping ring 9 may be pulled over the shorting ring 7 from the main disk 5 and the edge disk 6 after the electron beam welding.

[0036] A short circuit rotor according to the invention may be installed in general in an asynchronous machine, which also has an appropriate stator. The asynchronous machine may be used with special advantage inside a motor vehicle.