JPH0118664B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric motor, and more particularly, to a fastening structure between a rotor plate laminated iron core and an output shaft in an induction type, synchronous type, DC type, etc. electric motor.

Conventionally, in this type of electric motor, a method has generally been used in which the plate laminated rotor core and the output shaft are fastened together by shrink fitting or press fitting. That is, conventionally, as shown in FIG. 1, a shrink fit margin of usually about 0.03 to 0.04 mm is formed between the inner diameter d of the plate laminated rotor core 1 and the outer diameter D of the output shaft 2. A method is used in which the rotor core 1 is heated and expanded and then press-fitted into the output shaft 2 using a press device.

However, with this fastening method, when the electric motor operates at high speed, the shrinkage fit between the rotor core 1 and the output shaft 2 decreases due to centrifugal force, resulting in a decrease in output efficiency. For this reason, it has become necessary to control the shrink fit allowance, and high accuracy has been required in the machining of the rotor core 1 and the like. In addition, shrink fitting and press fitting processes are required, which requires large equipment and increases assembly costs. Furthermore, since it becomes impossible to disassemble the rotor core 1 and the output shaft 2, it becomes difficult to replace bearings and the like.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electric motor that can eliminate the above-mentioned drawbacks.

According to the present invention, the plate-stacked core of the rotor and the output shaft are connected by spline coupling, and the inner diameter of the metal rings provided on both sides of the plate-stacked core of the rotor in the axial direction is as described above. This is achieved by an electric motor characterized by a structure fitted to the outer diameter of the output shaft.

Embodiments of the present invention will be described below with reference to FIGS. 2 to 6 of the drawings.

2 to 5 schematically show the structure of a rotor and an output shaft when the present invention is applied to an induction motor. Referring to these figures, a plurality of spline grooves 11 are formed at equal intervals on the outer periphery of the output shaft 10. Rotor 2
0 is a slot 23 of a plate laminated core 22 constructed by laminating a large number of plates 21 made of magnetic material.
It is constructed by casting molten aluminum into. The aluminum in the slot 23 constitutes a conductor rod 24, and the aluminum at both ends of the iron core 22 constitutes a shorting ring 25. The slots 23 are formed at equal intervals over the entire circumference of the plate 21, but only some of the slots are shown in FIG. Iron core 2 of this aluminum die-cast type squirrel cage rotor 20
The inner diameter d of the iron core 2 is set slightly larger than the outer diameter D of the spline portion of the output shaft 10.
Spline teeth 26 that engage with each spline groove 11 of the output shaft 10 are formed on the inner periphery of the output shaft 10 . Each plate 21 of the iron core 22 having such a shape can be easily made by punching a plate material.

Here, iron rings 27 are provided at both ends of the aluminum die-cast squirrel cage rotor. The inner diameter of the iron ring 27 is the same as the output shaft 10.
The rotor 20 is machined with relatively high precision so as to fit onto the outer periphery of the spline portion with a dimensional tolerance within a predetermined range, thereby preventing wobbling or misalignment between the rotor 20 and the output shaft 10. iron ring 2
It is not difficult to process the inner diameter of No. 7 with relatively high precision. In the case of such a configuration, there is no need to increase the accuracy of the inner diameter of the plate 21, so accuracy control in punching the plate 21 becomes easier.

The iron core 22 of the rotor 20 is connected to the output shaft 10
is inserted into the spline and connected to the spline. Such assembly work can be easily performed without requiring any special equipment, and the two can be easily separated if necessary. The output shaft 10 is supported by a stator housing (not shown) via a bearing (not shown).

In the electric motor having the above configuration, the iron core 22 of the rotor 20 deforms slightly outward in the radial direction due to centrifugal action during high-speed rotation operation.
is connected to the output shaft 10 by a spline connection, so that the rotor 20 and the output shaft 1
No relative rotation occurs with respect to 0. Therefore, no reduction in output efficiency occurs.

FIG. 6 shows another embodiment of the present invention. In the figure, the same reference numerals as in FIGS. 2 to 5 indicate the same components as in the above embodiment.

In this embodiment, the output shaft 10 of the electric motor also serves as the main shaft of a headstock in a machine tool, and the stator housing 30 of the electric motor is formed integrally with the housing of the headstock. A flange 12 is integrally formed at one end of the output shaft 10 for attaching a workpiece chuck device (not shown). In this case, for example, in order to replace the bearing 31, it is necessary to once remove the rotor 20 from the output shaft 10, but the plate laminated core 22 of the rotor 20 is fastened to the output shaft 10 by spline connection. Therefore, the rotor 20 can be easily removed.

In this embodiment, an outer peripheral screw 13 is formed on the outer periphery of the output shaft 10, into which a nut 40 for regulating the axial position of the rotor 20 is screwed. The outer circumferential screws 13 may be formed on both ends of the rotor 20, but as shown in the figure, a stepped portion 14 is formed on the output shaft 10 at one end of the rotor 20, and the stepped portion 14 is Rotor 20
Alternatively, one end of the rotor 20 may be brought into contact with the other end of the rotor 20, and the nut 40 may be brought into contact with the other end of the rotor 20. The outer peripheral thread 13 of the output shaft 10 may be formed on the outer periphery of the spline portion.

Although the embodiments have been described above, the present invention is not limited to the above embodiments. For example, if the rotor has a plate laminated core,
The rotor may be a wound rotor for an induction motor, a rotor for a synchronous motor, a rotor for a DC motor, or the like.

As is clear from the above description, the present invention is characterized in that the plate laminated iron core of the rotor and the output shaft are connected by spline coupling, so that the present invention is free from the action of centrifugal force during high-speed rotational operation of the electric motor. The resulting decrease in output efficiency no longer occurs. Also, assembly of rotor and output shaft,
Disassembly, etc. can be easily performed without requiring large equipment, and assembly costs can be reduced.

[Brief explanation of drawings]

Fig. 1 is an exploded front view showing the structure of the plate laminated rotor core and output shaft of an electric motor showing the prior art, Fig. 2 is a front view of the output shaft of an electric motor showing an embodiment of the present invention, and Fig. 3 is in Figure 2.
A cross-sectional view along the line, Figure 4 is in Figure 5 of the rotor.
5 is a sectional view taken along the line in FIG. 4 of the rotor shown in FIG. 4; FIG. be. 10...Output shaft, 11...Spline groove, 1
3...Outer circumferential screw, 20...Rotor, 21...Plate,
22...Plate laminated iron core, 26...Spline tooth, 27...Iron ring, 40...Nut.

Claims (1)

[Scope of Claims] 1. A plate laminated core of a rotor which is rotatably provided inside a stator through a gap and an output shaft are connected by spline connection, and the plate laminated core of the rotor is connected in the axial direction. An electric motor characterized by a structure in which the inner diameter of metal rings provided on both sides is fitted to the outer diameter of the output shaft. 2. The electric motor according to claim 1, wherein the output shaft is formed with an outer circumferential thread into which a nut for regulating the axial position of the rotor is screwed. 3. The electric motor according to claim 1 or 2, wherein the output shaft also serves as a main shaft of a headstock in a machine tool.