JPH0726648B2 - Electric motor - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electric motor that forms a stepped portion by rolling on a shaft of a rotor and slides the metal on a metal.

[Prior Art] The shaft of an electric motor is rotatable and is regulated so as not to move in the axial direction.

When the bearing is a ball bearing, the shaft can be press-fitted into the inner ring of the ball bearing to regulate the axial position with sufficient strength even if a slight protrusion is formed on the shaft. In this case, since the shaft and the metal slide in the axial direction as well, the position regulation must show a certain degree of axial proof strength.

For this reason, generally, a step having a considerably large axial area in the radial direction is formed on the shaft by step machining that slides in the metal in the axial direction. Had formed.

However, if such a step is formed on the shaft, cutting work is required on the shaft, and if the diameter of the end of the shaft is determined, a thick shaft with the radial dimension added for the step is used as the material. However, there is a problem in that a thick material is required for the shaft.

For this reason, it is general that the position of the bearing is regulated by forming a step by a radial projection instead of forming a step by mechanical cutting on the shaft.

[Problems to be Solved by the Invention] When a step is formed on a shaft by a projection to control the position with respect to a bearing, the projection forms an axial surface of the same degree as a large step in a radial direction by machining, Moreover, if the axial surface is perpendicular to the axis, no problem will occur, but there is a problem in that the projection cannot be formed in the same manner as the step by cutting in terms of accuracy and strength.

That is, since the step by the protrusion is performed by plastic deformation of the shaft, the amount of protrusion in the radial direction is limited, the shaft is easily bent due to the formation of the protrusion, and the contact portion between the protrusion and the bearing is mechanically different. There is a problem in that high precision like cutting cannot be obtained.

In order to improve such problems as much as possible, a circumferential projection is formed on the shaft by rolling, and the side surface of the projection that slides with the bearing during rolling is shaped as a collar as if it were a step by mechanical processing. Some are getting.

With such a configuration, in the case of a bearing that is press-fitted to the shaft like a ball bearing, it is possible to obtain sufficient proof strength and accuracy for axial position regulation.

However, it is not possible to form the metal type bearing with high accuracy by sliding it on the rolled protrusion.

In other words, the formation of protrusions by rolling does not allow a large axial sliding area to slide the metal in the axial direction due to plastic deformation of the shaft. The boundary between the two becomes curved, and the sliding surface of the metal has to be machined, or a washer must be interposed between the protrusion and the metal.

However, even if a washer is interposed in the step, the step is often not exactly parallel to the metal end face, and the washer tilts and slides on the metal end face, which may impair reliability.

[Means for Solving the Problems] The first aspect of the present invention is, at least, the first step of contacting the co-stepped portion and tightly fitting the shaft.
And a second washer loosely fitted to the shaft,
The problem is solved by providing a rubber-type third washer fitted to the shaft and a fiber-type fourth washer fitted to the shaft and sliding on the metal.

[Operation] The first washer exhibits an axial proof stress with respect to the stepped portion, and the second washer and the third washer adjust the accuracy with respect to the axis perpendicular to the stepped portion, and the fourth washer. Has good sliding characteristics with respect to metal.

By combining these first to fourth washers, the metal can be slid on the stepped portion by rolling, and good sliding characteristics can be obtained.

[Embodiment] The present invention will be described based on an embodiment shown in the drawings. Fig. 1 is a longitudinal sectional view showing an essential part of an electric motor according to the present invention, and Fig. 2 shows the essential part. It is a longitudinal cross-sectional view of an enlarged main part.

In FIG. 1, the electric motor is provided with a rotor 2 on the inner diameter side of a stator 1, and the rotor 2 rotates relative to the stator 1 and its position is regulated in the axial direction. .

A shaft 3 penetrates through the rotor 2 and is fixed by caulking 4.

One end of the shaft 3 is rotatably supported by the metal 6 provided on the bracket 5, and the shaft end is regulated to one side by the sliding plate 7.

Further, the other side of the shaft 3 is formed with a stepped portion 8 formed by rolling, and a first washer 10 which comes into contact with the stepped portion between the metal 9 and the shaft 9 and is tightly fitted to the shaft, Second washer 11 that is loosely fitted to the third, rubber-type third washer and 12, fiber-type fourth washer that tightly fits on the shaft and slides on the metal
13 and 13 are interposed.

The metal 9 is supported by a bracket 14, and an oil core 15 is provided on the outer circumference.

In FIG. 2, the electric motor is a stepped portion 8 formed on the shaft 3.
The first washer 10 interposed between the metal and the metal is the shaft 3
It is configured to be tightly fitted to the shaft 3, and is abutted against the stepped portion 8 of the shaft 3 to regulate the shaft in the axial direction and has sufficient strength.

The second washer 11 is loosely fitted to the shaft 3 with respect to the shaft 3 and forms a gap 16.

Further, the third washer 12 is made of rubber and has elasticity, and the fourth washer 13 is made of a material such as fiber and has no resistance to sliding with the metal 9 and has less wear. It is composed of those exhibiting smooth sliding characteristics.

In such a configuration, the electric motor can be smoothly rotated by the metals 6 and 9 when the rotor 2 rotates, and the rotor 2
When it tries to move in the axial direction, the shaft end cannot move to one side by abutting against the sliding member 7, and the stepped portion 8 moves to the other side via the first to fourth washers. The position is regulated by abutting against the end surface of the metal 9.

The position regulation of the shaft 3 to the other side is such that the stepped portion 8 cannot be formed by a large protrusion in the radial direction due to its nature, and therefore the first washer 10 is interposed so that the entire stepped portion 8 is axially aligned. Is harnessing the power of.

When an axial force is applied to the stepped portion 8 through the first washer 10 in this manner, the stepped portion 8 exhibits sufficient proof strength in the axial direction as in the case where the ball bearing is press-fitted. be able to.

Further, the stepped portion 8 is not as accurate as the mechanically cut stepped portion, but since the second washer 11 is interposed in the shaft 3 in a loosely fitted state, the stepped portion 8 should be stepped on the end surface of the metal 9. If the parts 8 are not parallel, they have some adjustment effect.

Moreover, since the rubber-type third washer 12 is interposed, the inclination between the stepped portion 8 and the end surface of the metal 9 is absorbed, and further, the dimensional error between the stepped portion 8 and the metal 9 is prevented. Therefore, the stepped portion 8 can slide smoothly with respect to the metal 9.

Such a washer that is interposed in the shaft 3 may be additionally provided with an appropriate washer for adjusting the dimensions.
The configuration according to this embodiment is the minimum component.

EFFECTS OF THE INVENTION According to the present invention, the strength and accuracy of the stepped portion are increased by interposing the first to fourth washers to form the stepped portion on the shaft by rolling and slide the metal. The problem is solved, the sliding property with respect to the metal is good, and the same performance as the stepped portion of the shaft by the conventional machining can be exhibited, and the effect in the production of the electric motor is extremely large.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an essential part of an electric motor according to the present invention, and FIG. 2 is an enlarged vertical sectional view showing an essential part of the electric motor. 3 ... Shaft, 8 ... Stepped portion, 9 ... Metal, 10 ... First washer, 11 ... Second washer, 12 ... Third washer, 13 ... Fourth washer, 16 …… A gap.

Claims (1)

[Claims] 1. In a motor for forming a stepped portion by rolling on a shaft of a rotor and sliding it on a metal, a first washer which is in close contact with the co-stepped portion and is tightly fitted to the shaft, and the shaft. A second washer loosely fitted to the shaft, a rubber-type third washer fitted to the shaft, and a fiber-type fourth washer fitted to the shaft and sliding on metal. An electric motor characterized by that.