Method for producing a motor shaft of a rotor of an electric motor

Abstract

A motor shaft of an electric motor is produced by producing and interconnecting a first module and an additional module of the motor shaft. The first module of the motor shaft and/or the additional module of the motor shaft is or are provided with a module-end connection element by cold forming and/or by warm forming and/or by hot forming a base module. The first module of the motor shaft produced in this way and the additional module of the motor shaft produced in this way are then interconnected by joining the module-end connection elements on both ends. A motor shaft produced according to this method is formed of a correspondingly configured first module and a correspondingly configured additional module.

Claims

1. A method for producing a motor shaft of a rotor of an electric motor, comprising the following steps: producing a first module of the motor shaft and an additional module of the motor shaft; and interconnecting the first module and the additional module, wherein the first module of the motor shaft is produced by providing an inner wall of a hollow cylindrical longitudinal portion of a base module of the first module with an inner toothing as a module-end connection element on an end assigned to the additional module of the motor shaft, wherein the additional module of the motor shaft is produced by providing a base module of the additional module with an external toothing as a module-end connection element on an end assigned to the first module of the motor shaft, wherein the internal toothing and the external toothing of the base modules of the first and additional modules are configured to be brought into mutual engagement and, thereby, to mutually support the first and the additional modules of the motor shaft about a shaft axis of the motor shaft, wherein one of the first module of the motor shaft and the additional module of the motor shaft is provided with the module-end connection element by cold forming in the form of axial forming the respective base module, wherein the other one of the first module of the motor shaft and the additional module of the motor shaft is provided with the module-end connection element by cutting the respective base module, and wherein the first module of the motor shaft and the additional module of the motor shaft are interconnected by joining the module-end connection elements on both ends.

2. The method according to claim 1, wherein at least one of the first module of the motor shaft and the additional module of the motor shaft is produced by providing the respective base module with a bearing seat for rotatably mounting the motor shaft.

3. The method according to claim 2, wherein the at least one of the first module of the motor shaft and the additional module of the motor shaft is produced by providing the respective base module first with the bearing seat for rotatably mounting the motor shaft and then with the module-end connection element.

4. The method according to claim 1, wherein at least one of the first module of the motor shaft and the additional module of the motor shaft is produced by providing the respective base module with a coupling element on an end remote from the module-end connection element.

5. The method according to claim 1, wherein one of the first module of the motor shaft and the additional module of the motor shaft is produced as an anchor module and the other one of the first module of the motor shaft and the additional module of the motor shaft is produced as a coupling module.

6. The method according to claim 5, wherein the anchor module of the motor shaft is produced by providing the respective base module with a seat for an anchor of the electric motor.

7. The method according to claim 1, wherein the first module of the motor shaft and the additional module of the motor shaft are interconnected by joining the module-end connection elements on both ends by one of the following methods: forming, interlockingly joining and substance-to-substance joining.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be described in more detail in the following with reference to schematic drawings given by way of example, in which:

(2) FIG. 1 shows a modular motor shaft of an electric motor,

(3) FIG. 2 shows the shaft modules of which the motor shaft according to FIG. 1 consists, and

(4) FIG. 3 shows some representations for illustrating the method for producing the motor shaft according to FIG. 1.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(5) According to FIGS. 1 and 2, a modular motor shaft 1 of an electric motor consists of a first module provided as an anchor module 2 and additional modules which, in the embodiment shown, are coupling modules 3, 4.

(6) The anchor module 2 is provided with a first module-end connection element 5 on the end assigned to the coupling module 3 and a second module-end connection element 6 on the end assigned to the coupling module 4. The first module-end connection element 5 of the anchor module 2 is formed as a toothing which is formed in the inner wall of a hollow cylindrical longitudinal portion 7 of the anchor module 2. Correspondingly, a toothing formed in the inner wall of a hollow cylindrical longitudinal portion 8 of the anchor module 2 is provided as the second module-end connection element 6 of the anchor module 2. The two toothings cannot be seen in FIGS. 1 to 3 and consist of teeth which extend in parallel with a shaft axis 9 of the motor shaft 1.

(7) A bearing seat 10 for a roller bearing (not shown) for rotatably mounting the motor shaft 1 is located on the outside of the hollow cylindrical longitudinal portion 7 of the anchor module 2. Correspondingly, the hollow cylindrical longitudinal portion 8 of the anchor module 2 is provided with a bearing seat 11 for a roller bearing for rotatably mounting the motor shaft 1. A seat 13 for an anchor (likewise not shown) of the electric motor, more specifically for a laminated core of the anchor, is formed on a central part 12 of the anchor module 2 arranged between the hollow cylindrical longitudinal portions 7, 8.

(8) On the end assigned to the anchor module 2, the coupling module 3 comprises a module end provided with an external toothing as the module-end connection element 14, which module end is structurally identical to a module-end connection element 15 of the coupling module 4.

(9) The external toothings on the coupling modules 3, 4 are adapted, with respect to their geometry, to the internal toothings provided as module-end connection elements 5, 6 of the anchor module 2. The external toothings on the coupling modules 3, 4 and the internal toothings on the anchor module 2 can consequently be brought into mutual engagement, the intermeshing external and internal toothings being supported against one another about the shaft axis 9 with zero clearance.

(10) On the end remote from the module-end connection element 14, the coupling module 3 is provided with a coupling element 16 which is formed in the embodiment shown as a module end that has a polygonal cross section.

(11) A seat 17 for the shaft-end part of a rotary encoder for measuring the speed of the motor shaft 1 directly adjoins the coupling element 16 in the axial direction of the coupling module 3.

(12) The coupling module 4 comprises a coupling element 18 on the end remote from the module-end connection element 15, which coupling element corresponds to the coupling element 16 on the coupling module 3 insofar as the coupling element 18 also forms a module end that is polygonal in cross section. The coupling element 16 of the coupling module 3 and the coupling element 18 of the coupling module 4 differ from one another in terms of structure insofar as the coupling element 18 has a greater axial length than the coupling element 16. A seat 19 on the coupling module 4 for a shaft-end part of the rotary encoder for measuring the speed of the motor shaft 1 is immediately adjacent to the coupling element 18 in the axial direction.

(13) FIG. 3 illustrates the sequence of the method for producing the motor shaft 1, the method steps at 1. relating to the coupling module 3, the method steps at 2. relating to the anchor module 2, and the method steps at 3. relating to the coupling module 4.

(14) The representations for illustrating the production of the coupling module 3 start with the view of a base module 3a that is present as a semi-finished product. In the embodiment shown, the base module 3a has been manufactured from a steel blank by a material-removing separation. Alternatively, it would also have been possible, inter alia, to produce the base module 3a by forming, for example by hot forming or by rotary swaging from a corresponding blank.

(15) In method step 1.1, the base module 3a is provided with the seat 17 for the shaft-side part of the rotary encoder by cutting. Moreover, in the region immediately adjacent to the seat 17, the base module 3a is formed into the coupling element 16.

(16) In method step 1.2, on the end of the base module 3a remote from the coupling element 16 and the seat 17, the external toothing provided as the module-end connection element 14 is produced by cutting. The production of the coupling module 3 is thus completed.

(17) Correspondingly, a base module 4a for the coupling module 4 is likewise manufactured from a steel blank and the coupling module 4 is produced from the base module 4a by making the seat 19 for the shaft-side part of the rotary encoder, the coupling element 18 and the module-end connection element 15.

(18) The starting point for manufacturing the anchor module 2 is a steel base module 2a, which has been made as a semi-finished product by cutting or forming machining of a blank.

(19) In method step 2.1, the bearing seats 10, 11 are produced on the ends of the base module 2a by cutting and subsequently the hollow cylindrical longitudinal portions 7, 8 are likewise made by cutting machining the base module 2a. In method step 2.2, the axis-parallel inner walls of the hollow cylindrical longitudinal portions 7, 8 are then provided, in the embodiment shown, with the internal toothings provided as the module-end connection elements 5, 6 by cold forming, more specifically by axial forming.

(20) In method step 2.3, the production of the seat 13 for the anchor of the electric motor follows the production of the module-end connection elements 5, 6. For this purpose, connecting elements are produced by cold forming on the central part 12 of the anchor module 2 thus completed, by way of which connecting elements the laminated core of the anchor can be fixed in position on the central part 12 of the anchor module 2.

(21) Finally, the motor shaft 1 is assembled from the anchor module 2 and the coupling modules 3, 4 by a joining process (indicated by arrows in FIG. 3). For this purpose, the module-end connection element or the external toothing 14 on the coupling module 3 is pushed into the hollow cylindrical longitudinal portion 7 on the anchor module 2 and the module-end connection element or the external toothing 15 on the coupling module 4 is pushed into the hollow cylindrical longitudinal portion 8 of the anchor module 2. When the connection elements 5, 14; 6, 15 on both ends are in mutual engagement, by exerting a radially inwardly directed force on the outside of the hollow cylindrical longitudinal portions 7, 8 and by associated forming of the hollow cylindrical longitudinal portions 7, 8, a frictional connection is additionally produced between the module-end connection elements 5, 14; 6, 15 on both ends.

(22) The intermeshing toothings of the module-end connection elements 5, 14; 6, 15 produce an interlocking connection between the anchor module 2 and the coupling modules 3, 4, owing to which interlocking connection the motor shaft 1 is able to transfer forces in the direction of rotation about the shaft axis 9. The anchor module 2 and the coupling modules 3 and 4 are secured to one another in the axial direction of the motor shaft 1 by the frictional connection between the module-end connection elements 5, 14: 6, 15 acting in the axial direction.

(23) If required, the above method steps for the production of the motor shaft 1 may be followed by additional method steps. In particular a cutting and/or forming process is conceivable for limiting manufacturing tolerances occurring at the motor shaft 1 to a permissible level, which process follows the joining of the module-end connection elements 5, 14; 6, 15.

(24) Since the coupling module 3 can be connected, by the module-end connection element 14, to the anchor module not only at the module-end connection element 5 of the anchor module 2 but also at the module-end connection element 6 of the anchor module 2, and since a connection is also possible between the coupling module 4 and the anchor module 2 not only at the module-end connection element 6 but also at the module-end connection element 5 of the anchor module 2, the anchor module 2 and the coupling modules 3, 4 provided as the additional modules form a set of modules of which the modules can be combined in different manners to form a motor shaft and which accordingly gives the possibility of configuring motor shafts for various uses.