Method for Producing a Rotor of an Asynchronous Machine

Abstract

A method for producing a rotor of an asynchronous machine includes providing a rotor lamination stack having grooves extending parallel to a rotor axis of the rotor, inserting conductor rods into the grooves such that the conductor rods protrude from end faces of the rotor lamination stack, wherein a twisting tool is placed at each of the end faces onto the protruding conductor rods and the twisting tools are twisted relative to each other, where the parallel grooves with the corresponding conductor rods also extend obliquely after the twisting and where the twisting tools are formed such that the protruding conductor rods remain parallel to the rotor axis when an oblique profile of the stack is produced, removing the twisting tools, providing first and second short-circuit washers, and axially pressing the short-circuit washers onto the conductor rods projecting perpendicularly from the end face of the rotor lamination stack.

Claims

1.-5. (canceled)

6. A method for producing a rotor of an asynchronous machine, the method comprising: providing a laminated rotor core with slots which extend parallel to a rotor axis of the rotor; inserting conductor rods into the slots such that the conductor rods protrude from end faces of the laminated rotor core; mounting a twisting tool onto the conductor rods so as to protrude from each of the end faces, twisting tools being twisted relative to each other, and parallel slots with respective conductor rods also extending in a skewed manner after the twisting has occurred, and the twisting tools being configured such that protruding conductor rods remain parallel to the rotor axis when a skewed core is produced; removing the twisting tools; providing a first and second short-circuiting disk; and axially force-fitting first and second short-circuiting disks onto the conductor rods protruding perpendicularly from the end faces of the laminated rotor core.

7. The method as claimed in claim 6, wherein axial bracing is achieved as a result of pressing on the first and second short-circuiting disks.

8. The method as claimed in claim 6, wherein said providing the laminated rotor core includes loosely lining up rotor laminations to form the laminated rotor core, and wherein said twisting produces a non-positive connection between the laminated rotor core and the conductor rods.

9. The method as claimed in claim 7, wherein said providing the laminated rotor core includes loosely lining up rotor laminations to form the laminated rotor core, and wherein said twisting produces a non-positive connection between the laminated rotor core and the conductor rods.

10. The method as claimed in claim 6, wherein the conductor rods and the short-circuiting disks material comprises one of aluminum, copper, an aluminum alloy and copper alloy.

11. The method as claimed in claim 7, wherein the conductor rods and the short-circuiting disks material comprises one of aluminum, copper, an aluminum alloy and copper alloy.

12. The method as claimed in claim 8, wherein the conductor rods and the short-circuiting disks material comprises one of aluminum, copper, an aluminum alloy and copper alloy.

13. The method as claimed in claim 10, wherein at least the material of the short-circuiting disks is heated above the recrystallization temperature, and the axial force-fitting of at least one short-circuiting disk onto the conductor rods protruding from the end faces of the laminated rotor core is advantageously effected with subsequent or concurrent hot forming of the short-circuiting disks which are axially pushed-on, taking a temperature range, deformation and deformation rate into account.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention is explained in greater detail with reference to an exemplary embodiment, in which:

[0022] FIG. 1 shows a schematic longitudinal section of an asynchronous motor in accordance with the prior art;

[0023] FIG. 2 shows the method steps from left to right with the twisting tool in accordance with the invention; and

[0024] FIG. 3 shows the pressing on of the short-circuiting disks in accordance with the invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0025] FIG. 1 shows a schematic longitudinal section of an asynchronous machine 1 with a stator 2, this having at its end faces a winding system 3 that takes the form of end windings there. The winding system 3 in this case can be constructed, for example, using toothed coils, preformed coils, and tooth-wound coils of different or identical coil width.

[0026] An air gap 17 of the asynchronous machine 1 separates the rotor 4 from the stator 2. The rotor 4 has a laminated rotor core 5. A first short-circuiting disk 7a and a second short-circuiting disk 7b are arranged at the end faces 15a,15b of the laminated rotor core 5. The rotor 4 is carried on a shaft 19.

[0027] FIG. 2 illustrates the inventive method steps. The method steps run from left to right. In a first step, the laminated rotor core 5 is provided with slots 8 that extend parallel to a rotor axis 4a of the rotor 4. This can be effected in particular by loosely lining up individual rotor laminations to form the laminated rotor core 5. In a next step, conductor rods 6 are inserted into the slots 8. With respect to the simplified illustration, it should be noted that although only one slot 8 is depicted in the drawings, at least a second slot will be present on the opposite side.

[0028] In a further step, a first and a second twisting tool V1,V2 are provided and the first and the second twisting tool V1,V2 are axially mounted on the conductor rods 6 protruding from the end faces 15a,15b of the laminated rotor core 5. In a next step, the first twisting tool V1 is twisted about a presettable angle a relative to the second twisting tool V2 via reciprocally opposing torques D1,D2, where the parallel slots 8 and the conductor rods 6 arranged therein then also extend in a skewed manner after the twisting has occurred. The twisting also involves a non-positive connection between the laminated rotor core 5 and the conductor rods 6. The axial force-fitting of the short-circuiting disks 7a,7b, taking into account an ideal temperature range for the deformation and the optimal deformation rate, is shown in FIG. 3. In this way, a plastic distortion occurs as a result of dislocation travel of the atomic planes in the lattice. This travel and therefore the overcoming of obstacles in the atomic lattice (for example, edge dislocation, and/or foreign atoms) is assisted by an increase in temperature. The deformability therefore increases with an effect from a specific material-dependent temperature threshold. The deformation rate, the temperature and the flow rate of the respective material must also be compatible with each other.

[0029] In this way, a microbond is formed between the material of the short-circuiting disks 7a,7b and the conductor rods 6. This microbond is produced as a result of the conductor rod 6 and the short-circuiting disks 7a,7b rubbing tightly against each other, thereby generating a surface pressure and further frictional heat. In this case, the permitted shear stress of these materials is locally exceeded and mass transfers are caused by diffusion at the boundary surface between the conductor rod 6 and the short-circuiting disk 7a,7b. This results in microwelds and microbonds.

[0030] In a next step, the first twisting tool V1 is twisted about a presettable angle a relative to the second twisting tool V2 via reciprocally opposing torques D1,D2, where the parallel slots 8 and the conductor rods 6 arranged therein then also extend in a skewed manner after the twisting has occurred. The twisting also involves a non-positive connection between the laminated rotor core 5 and the conductor rods 6.

[0031] Thus, while there have been shown, described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the methods described and the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.