Rotor of cage rotor-motor and method for producing such rotor

Abstract

The invention relates to a rotor of a cage rotor motor and to a method for producing the rotor, in which the rotor has a short-circuiting cage, and the rotor rods (2) of the short-circuiting cage extend in the axial direction through a cylindrical rotor body (1) and are connected to one another in each case by short-circuiting rings (7) on the end faces (4) of the rotor body, and in which the rotor rods (2) of the short-circuiting cage extend in the axial direction through the cylindrical rotor body (1) and are connected to one another by short-circuiting rings (7) on the end faces (4) of the rotor body (1). The short-circuiting ring (7) is applied directly to the end face (4) of the cylindrical rotor body (1) by means of an additive machining method.

Description

Technical Field

[0001] The invention relates to a rotor of a cage rotor motor and a method for producing the rotor. Background Art

[0002] In asynchronous machines, a so-called short-circuit cage is usually arranged in a rotor that is rotatably mounted relative to a stator. The rotor of an asynchronous machine is therefore also called a cage rotor or short-circuit rotor. The short-circuit cage has short-circuit bars that are usually arranged parallel to the rotation axis of the cage rotor or slightly inclined, that is, extending in the axial direction.

[0003] The short-circuit bar is inserted into a rotor base body which is usually formed as a lamination package consisting of a plurality of laminations stacked axially adjacent to one another.

[0004] The short-circuit bars are inserted into recesses or grooves in the lamellae. The short-circuit bars are electrically connected to one another at their ends via short-circuit rings arranged at the two end-side ends of the rotor base body.

[0005] An example of a short-circuited rotor of an asynchronous machine is described in DE 195 42 962 C1.

[0006] During operation of the electric machine, a strong current is induced in the short-circuit cage due to the changing magnetic field. In order to keep the resistance losses low, the short-circuit cage is usually made of a material with high electrical conductivity, such as copper, aluminum or alloys thereof.

[0007] However, the materials mentioned have a relatively low mechanical strength.

[0008] When the rotor is accelerated to high rotational speeds, components of the short-circuit cage, in particular the exposed short-circuit rings, tend to deform due to centrifugal forces. A possible reduction in the strength of the components, such as occurs at high temperatures that often occur during operation, can further intensify the tendency to deformation.

[0009] Therefore, it is proposed in DE 102014220267 A1 to protect the mechanically less stable short-circuit rings of the short-circuit cage against radial deformations caused, for example, by severe centrifugal forces occurring at high rotational speeds by means of support disks, which can be arranged at the end faces of the plate package similar to the cover plates and which can stabilize the short-circuit rings with an area close to the edge that is bent axially away from the plate package.

[0010] EP 3823142 A1 discloses a short-circuit rotor in which, for absorbing centrifugal forces, a supporting element made of a high-strength material is radially present within the short-circuit ring and is connected to the short-circuit ring at least in sections by a materially bonded connection.

[0011] In order to prevent deformation of the short-circuit ring, it is conventionally also supported by a hoop which surrounds it from the outside.

[0012] The measures mentioned increase the costs and complexity of the asynchronous machine. Summary of the invention

[0013] The invention is therefore based on the object of specifying a rotor for a squirrel-cage rotor motor which is suitable for high rotational speeds and which can be easily produced.

[0014] This is achieved according to the invention with a rotor according to claim 1 and a method according to claim 7 .

[0015] Advantageous embodiments of the invention are revealed in the dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be explained in more detail with reference to the accompanying drawings. It is shown by way of example:

[0017] 1, 2, 3 and 4 show different embodiments of the rotor according to the invention.

[0018] Figure 5 , Figure 6 and Figure 7 A further embodiment is shown having a rotor with a layered structure. DETAILED DESCRIPTION

[0019] FIG. 1 shows four views of a rotor according to the invention at different stages of the manufacturing process, FIG. 1a showing a cylindrical rotor body 1 before being fitted with a short-circuit rod 2, which has still open holes provided for receiving the rotor rod 2, which holes are located in a section of the end face which extends conically in the exemplary embodiment, but the end face can also have other courses without limiting the invention.

[0020] FIG. 1 b shows the rotor with the short-circuit bars already inserted, and FIG. 1 c shows the rotor with the rotor bars processed so that they terminate flush with the conically extending outer section of the rotor end face.

[0021] FIG. 1 d shows the finished rotor with the short-circuiting rings which are applied to the rotor body by means of an additive manufacturing method (3D printing), such as preferably the “wire-fed electron beam additive manufacturing” method.

[0022] Alternatively, however, for example, “cold spray additive manufacturing”, “wire / powder laser metal deposition” methods, “friction deposition additive manufacturing”, “rotary friction welding” or “ultrasonic additive manufacturing” can also be used for the application process.

[0023] The method mentioned makes it possible to achieve a stable connection between a short-circuit ring, which is made of copper, aluminum or a suitable alloy, for example, and a rotor body, which is made of steel, for example. This stable connection significantly increases the resistance of the short-circuit ring to centrifugal forces and enables the use of the rotor for higher rotational speeds with only a low outlay on material and processing.

[0024] The additive methods mentioned can be combined with other processing methods such as, for example, electroplating, brush plating, electron beam welding, laser beam welding, soldering or explosive bonding in order to produce permanent connections between different materials.

[0025] Figure 2 shows different stages in the manufacture of another rotor according to the invention, wherein, as shown in Figure 2a, in a first step, a thin copper layer or the desired material combination is applied to the end side of the rotor using an additive processing method or by means of electroplating coating or explosion bonding, after which Figure 2b realizes the hole for the rotating part rod, Figure 2c realizes the insertion of the rotating part rod, Figure 2d realizes the flush end, and Figure 2e realizes the application of the short-circuit ring 7.

[0026] FIG3 shows a further embodiment in which the rotor rod 2 is designed in the form of a rod and is inserted into a groove 5 of the rotor 1. In this embodiment, in a first step, FIG3a also applies a thin copper layer or the desired material combination to the end face of the rotor 1, but this is only done if additive processing methods are not suitable for the application process directly on the shaft / rotator rod, after which FIG3b mills the groove 5 for receiving the rotor rod 2, FIG3c inserts the rotor rod 2, and FIG3d shortens these rotor rods flush and applies the actual short-circuit ring 7.

[0027] 4 shows a further embodiment in which, unlike the previous examples, the short-circuit ring 7 is not applied directly to the end face of the rotor, but is inserted slightly spaced apart from the end face into a circumferential groove 6 of the rotor. However, the procedure for producing the rotor 1 corresponds largely to that of the other examples.

[0028] Figure 5 , Figure 6 and Figure 7 An embodiment with a rotor body 1 is shown in each case, which is designed as a plate pack consisting of a plurality of plates 9 stacked axially next to each other. At the end, the plate pack is closed by a steel ring 8, to which a short-circuit ring 7 is applied. It should be noted that the invention can also be used in the same way in a solid rotor body made of steel.

[0029] In accordance with Figure 5In the exemplary embodiment of , the steel ring 8 has, for example, a conically extending section of the end face, the short-circuiting ring being designed in such a way that it forms, together with the rotor base body, a cylinder with end faces extending uniformly orthogonally to the axis of rotation.

[0030] In accordance with Figure 6 and Figure 7 In the embodiment of the present invention, the steel ring 8 has a smaller circumference than the rotating part body, and the short-circuit ring 7 is applied to the circumference of the steel ring 8 in the described method and manner, so as to form a cylinder with a uniform circumferential side surface with the rotating part base body after application.

[0031] List of reference numerals:

[0032] Rotating part body 1

[0033] Rotating rod 2

[0034] Hole 3

[0035] End side 4 of the rotating part body

[0036] Groove 5

[0037] Surrounding groove 6

[0038] Short circuit ring 7

[0039] Steel ring 8

[0040] Plate 9

[0041] Rotor rod 10.

Claims

1. Cage-type rotor-the rotor of a motor, the rotor having a short-circuit cage, wherein: The rotating rods (2) of the short-circuit cage extend in the axial direction through the cylindrical rotating body (1) and are connected to each other via short-circuit rings (7) at or near the end faces (4) of the rotating body, characterized in that the short-circuit rings (7) are applied directly to the end faces (4) of the cylindrical rotating body by means of an additive manufacturing method.

2. The rotor according to claim 1, characterized in that The "Electron Beam Wire Additive Manufacturing" method is set as the additive processing method.

3. The rotor according to claim 1, characterized in that The "Cold Spray Additive Manufacturing" method is set as the additive processing method.

4. The rotor according to claim 1, characterized in that The "Wire / Powder Laser Metal Deposition" method is set as the additive processing method.

5. The rotor according to claim 1, characterized in that The "Friction Deposition Additive Manufacturing" method or "Spin Friction Welding" is provided as the additive processing method.

6. The rotor according to claim 1, characterized in that The "Ultrasonic Additive Manufacturing" method is set as the additive processing method.

7. The rotor according to claim 1, characterized in that The additive manufacturing method according to claims 2 to 6 can also be combined with electroplating, explosive lamination, electron beam welding, laser beam welding or brazing processes.

8. The rotor according to any one of claims 1 to 7, characterized in that Copper or a copper alloy is provided as the material for the short-circuit ring (7).

9. The rotor according to any one of claims 1 to 7, characterized in that Aluminum is provided as the material for the short-circuit ring (7).

10. The rotor according to any one of claims 1 to 7, characterized in that The cylindrical rotating body (1) has a plate group consisting of a plurality of plates (9) stacked side by side in the axial direction.

11. A method for producing a rotor of a cage rotor motor, wherein: In the rotor body, the rotor rod (2) of the short-circuit cage is inserted into a prepared recess (3) of the cylindrical rotor body (1), characterized in that the short-circuit ring (7) is applied directly to or near the end side (4) of the cylindrical rotor body (1) by means of an additive manufacturing method.

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