JPS5842703B2 - Dendokino Kaitenshi Keihouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotor of an electric motor suitable for use as an electric motor of a direct drive type cassette tape recorder, for example, and a method of forming the rotor, and particularly to a rotor that eliminates shaft wobbling of the electric motor.

Conventionally, as a method for forming a rotor for this type of electric motor, a method as shown in FIG. 1A-0 has been used.

As shown in Fig. 1A, a plurality of plate-shaped iron cores 2 are press-fitted into a shaft 1 and laminated, and the stacked iron cores are fixed to the shaft 1 by applying pressure from both ends and caulking them to the shaft. A winding 3 is provided on this core as shown in FIG. 1B, and a commutator 5 is further inserted into and tightly attached to one end of the shaft.

Note that 4 is a spacer for separating the winding and the shaft.

By the way, in general, in a direct drive type tape recorder, if there is shaft vibration in the electric motor used, the effect will directly appear on the tape recorder as wow and flutter. It is preferable to use one without.

However, as shown in the example in Fig. 1, the iron core 2 stacked on the shaft 1
When the iron core 2 is crimped and fixed to the shaft by applying pressure from both ends, the shaft 1 is bent within the elastic limit due to the stress of the iron core 2 in response to the pressure at the time of crimping.

Furthermore, since the iron core 2 is press-fitted directly onto the shaft 1 and laminated, there is a risk that the shaft 1 will be bent due to an error in the position of the insertion hole of the iron core 2 to the shaft 1, or a crack in the insertion hole.

If the shaft 1 is bent in this way, this will result in shaft wobbling, which is undesirable.

In view of this, the present invention provides a rotor for an electric motor and a method for forming the rotor, which prevents the rotor from being bent and minimizes shaft wobbling.

Hereinafter, an example of a method for forming a rotor of an electric motor according to the present invention will be explained with reference to the drawings.

In the present invention, a rotor bush is used without directly press-fitting and laminating the iron core around the axis.

That is, in Fig. 2, 6 indicates this rotor bush, and as is clear from the figure, this is a hollow cylinder, and one end of the hollow part is a net hollow part 6a that is thinner than the other part, and the shaft is inserted into this part. It is done like this.

Then, as shown in FIG. 2A, this rotor bush 6
A plurality of iron cores 7 are press-fitted from the open end side with the larger inner diameter and stacked.

Next, as shown in FIG. 2B, a winding 8 is applied to the rotor bush 6 and the iron cores laminated by press-fitting, and the portions of the winding 8 that protrude to the outside are pressed and shaped.

After doing this, as shown in FIG. 2C, insert the shaft 9 into the net hollow part 6a of the rotor bush 6,
The rotor tab bush 6 is fixed to the shaft 9 by caulking one side of the net hollow part 6a of the tab bush to the shaft 9 in the centripetal direction as shown by arrows a and a' in FIG. 2C.

Furthermore, as shown in the second diagram, the commutator 10 is inserted and mounted from the side where the shaft 9 is fixed.

The rotor of the electric motor is formed as described above.

As described above, according to the present invention, without directly press-fitting the iron core into the shaft, a rotor bush having a mesh hollow portion with a diameter slightly larger than the diameter of the shaft is used at one end, and one side of the rotor bush is attached to the shaft. Since the part to be crimped is 1
Good in a few places.

In addition, since the shaft is inserted and fixed into the hollow part of the net at one end of the rotor bush, almost no force is generated to bend the shaft compared to a case where the inner diameter of the hollow part of the rotor bush is made uniform.

Furthermore, since the laminated core is press-fitted into the rotor bushing from the open end side with the larger inner diameter, there is almost no effect on the hollow net portion of the rotor bushing, which is largely related to shaft runout.

Therefore, the shaft runout of the motor can be minimized, and when the motor produced according to the present invention is used as a direct drive motor, very good performance can be obtained.

Further, in this invention, the rotor shaft is press-fitted into the rotor bushing from the open end side of the rotor bushing having a larger inner diameter, so that the following effects can be obtained.

In other words, this hollow part of the rotor bush with a large inner diameter is thinner than the hollow part of the net, so when the rotor shaft is press-fitted into the hollow part of the net, this thin part deforms elastically, so that the rotor shaft is press-fitted into the hollow part of the net. It is easy to use, and furthermore, the rotor shaft is held by the return force of this elastic deformation after press-fitting.

In this case, the inner diameter of the part of the rotor bushing other than the narrow cavity is large and there is a clearance between it and the rotor shaft, so this part will get in the way when inserting the rotor shaft after press-fitting the iron core into the rotor bushing. There is no such thing.

[Brief explanation of drawings]

Figure 1 A, B, C! 2A, B, 0 are cross-sectional views for explaining an example of a rotor of a conventional electric motor and a method of forming the shaft.
．． D is a sectional view illustrating an example of a rotor of an electric motor and a method of forming the same according to the present invention. 6 is a rotor bushing, 7 is an iron core, 8 is a winding wire, 9 is a shaft, 1
0 is a commutator.

Claims (1)

[Scope of Claims] 1. A hollow cylindrical rotor bushing, a predetermined number of laminated cores press-fitted into the outer periphery of the rotor bushing, and a rotor also inserted into the hollow part of the rotor bushing. One open end side of the hollow part of the rotor tab bush is a narrow hollow part whose inner diameter is smaller than the other part, and the rotor shaft is inserted into this narrow hollow part, and the rotor shaft is inserted into this narrow hollow part. A rotor for an electric motor, wherein the rotor bushing is fixed to the rotor shaft by caulking on one side of the width cavity. 2. A rotor bushing is prepared which is hollow and cylindrical, and has a narrow hollow part where one open end of the hollow part has a smaller inner diameter than the other part, and on the outer periphery of this rotor bush, there is a hollow part with a larger inner diameter. After a predetermined number of laminated cores are press-fitted from the other open end side of the rotor bush, a rotor shaft whose diameter is slightly smaller than the inner diameter of the narrow cavity is inserted into the narrow cavity of the rotor bushing. A method of forming a rotor for an electric motor, wherein one side of the rotor bush is caulked in a centripetal direction to fix the rotor shaft to the rotor bush.