JPH0847190A - Electric motor - Google Patents

Abstract

PURPOSE:To obtain an electric motor which can be manufactured easily without applying an adhesive to a permanent magnet and without using a complicated process such as a molding process or the like and which is provided with a permanent-magnet rotor with a favorable axis. CONSTITUTION:In an electric motor, a cylindrical permanent magnet 9 is constituted of a plastic magnet, a protrusion part 10 which is installed so as to protrude to the axial direction is formed on the inside-diameter side of the permanent magnet 9, a groove 11 to which the protrusion part 10 can be fitted is formed on the outer circumference of a core 8, the length in the axial direction of the permanent magnet 9 is made large with reference to the core 8, the permanent magnet 9 is fitted to the core 8, the end part in the axial direction of the protrusion part 10 is deformed at the side end of the core 8 by a plastic deformation operation, the core 8 is fixed to the permanent magnet 9 so as to constitute a permanent-magnet rotor 6, and the permanent-magnet rotor 6 is mounted internally.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric motor having a permanent magnet rotor formed by fitting a permanent magnet around the outer circumference of an iron core.

[0002]

2. Description of the Related Art An electric motor provided with a permanent magnet rotor is provided with a shaft on the permanent magnet rotor so that it can rotate in a stator having windings, and the permanent magnet is provided on the outer circumference of the shaft through an iron core. Are configured to be attached. In the permanent magnet rotor configured in this way, the shaft and the iron core can be relatively easily and accurately manufactured by a method such as press fitting or caulking, but the material of the iron core and the permanent magnet are different from each other. It is not easy because the permanent magnet is brittle and the permanent magnet has a brittle property, and the fixing method by adhesion is exclusively used. Since the shaft is configured to be rotatably supported by the stator, the outer circumference of the permanent magnet rotor and the inner circumference of the stator must be accurately aligned if the axes of the shaft and the permanent magnet are not exactly aligned. May cause contact. For this reason, a gap is formed between the permanent magnet rotor and the stator in a range where assembly tolerances and the like can be absorbed. Therefore, since this air gap has an extremely large influence on the operation efficiency of the electric motor, the operation efficiency is determined by how small the air gap is.

[0003]

In such a fixing method by bonding the iron core and the permanent magnet, since the adhesive is interposed between the iron core and the permanent magnet, the accuracy of mounting the permanent magnet on the shaft is high. It had a problem of not being good.
In addition, since it takes time for the adhesive to completely harden, it has been practically difficult to use under conditions such as mass production in which the adhesive must be manufactured in a short time.

As a method of solving such a problem, it has been attempted to integrally form a plastic magnet or the like. However, when manufacturing those having different dimensions including other members such as a shaft, different molding dies have to be manufactured, so that there is a problem that it is not suitable for various kinds of products. Further, the shaft and the iron core have to be inserted into the molding die, which causes a problem that the manufacturing is troublesome.

The present invention has been made in view of such circumstances, and is possible without using an adhesive for a permanent magnet.
The object is to obtain a motor with good operating efficiency by configuring a highly accurate permanent magnet rotor without using complicated steps such as molding.

[0006]

According to the present invention, a plastic permanent magnet constitutes a cylindrical permanent magnet, and an axially extending projection is formed on the inner diameter side of the permanent magnet. A groove that can be fitted is formed on the outer circumference of the iron core, the axial length of the permanent magnet is increased with respect to the iron core, and further, the permanent magnet is fitted to the iron core and the axial end portion of the protruding portion is made plastic. The problem is solved by deforming at the side end of the iron core by deformation and fixing the iron core and the permanent magnet.

[0007]

The protrusion of the permanent magnet is fitted into the groove of the iron core to restrain the relative movement in the rotation direction, and the axial end of the protrusion is heated to be plastically deformed. As a result, the protrusion cannot move in the axial direction with respect to the groove of the iron core, the movement in the axial direction can be restricted, and the iron core and the permanent magnet are fixed in the rotational direction and the axial direction. Since the shaft and the iron core can be in close contact with each other, the accuracy is good, and since the iron core and the permanent magnet can be directly contacted with each other without using an adhesive, the accuracy is good, and the assembly tolerance is extremely small. The axis of and will match exactly.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention as described above will be explained based on an embodiment shown in the drawings. FIG. 1 is a longitudinal sectional view of an electric motor of the present invention having a permanent magnet rotor. FIG. 2 is a perspective view of a permanent magnet rotor used in the present invention. FIG. 3 is a vertical sectional view of the permanent magnet rotor. FIG. 4 is a perspective view of a main part showing a state in which the permanent magnet rotor is assembled. Figure 5
It is a longitudinal cross-sectional view of a main part showing a state in which a permanent magnet rotor is assembled.

In FIG. 1, in a motor, a doughnut-shaped stator core 1 is wound with a winding 2 to form a stator 3. The outer periphery of the stator 3 is premixed to form a frame 4. Further, the frame 4 is provided with bearings 5a and 5b at both end portions in the axial direction, and the bearings 5a and 5b include the shaft 7 of the permanent magnet rotor 6.
Supports to rotate.

An iron core 8 is press-fitted and fixed to a shaft 7 of the permanent magnet rotor 6, and a cylindrical permanent magnet 9 is provided on the outer periphery of the iron core 8. The permanent magnet 9 has a protrusion 10 formed on the inner periphery thereof, and a groove 11 into which the protrusion 10 is fitted is formed on the outer periphery of the iron core 8. Further, the permanent magnet 9 is made of a plastic magnet, is formed to be larger than the width of the iron core 8 in the axial direction, and the protruding portion 11 forms the fixing portion 12 by plastic deformation at the side end of the iron core 8. .

Further, since the frame 4 has the permanent magnet rotor 6 incorporated in the stator 3, the bracket 1 is provided on one side in the axial direction.
3 is formed, and the bracket 13 is configured to be integrated with the frame 4 by a method such as mounting the permanent magnet rotor 6 inside and then bonding.

In FIG. 2, the permanent magnet rotor 6 has a shaft 7
An iron core 8 is provided coaxially with the
It is provided coaxially with. The four protruding portions 10 of the permanent magnet 9 are evenly arranged along the inner circumference of the permanent magnet 9. Further, the protruding portion 10 forms a fixed portion 12 by plastic deformation at the side end of the iron core 8.

In FIG. 3, the permanent magnet rotor 6 has a shaft 7
An iron core 8 is press-fitted and fixed to the core core 8, and a permanent magnet 9 is attached to the outer periphery of the iron core 8 to form a permanent magnet rotor 6. A protrusion 10 is formed on the inner circumference of the permanent magnet 9, fitted into the groove 11 of the iron core 8, and the protrusion 10 is plastically deformed at the side end of the iron core 8 to form the fixed portion 12. .

In FIG. 4, the protruding portion 10 of the permanent magnet 9 is shown.
Is fitted in the groove 11 of the iron core 8, and is heated at the side end of the iron core 8 by the heated iron 14 or the like, and is plastically deformed by being strongly pressed by the iron 14 in the softened state. A fixing portion 12 having a large width is formed.

In FIG. 5, the permanent magnet rotor 6 has a shaft 7
It is shown that the iron core 8 is press-fitted and fixed to the core, and that the protruding portion 10 formed on the inner circumference of the permanent magnet 9 is fitted into the groove 11 formed on the outer circumference of the iron core 8. A positioning portion 15 that abuts the side end of the iron core 8 is formed at one end of the protrusion 10 of the magnet 9. Therefore, when the permanent magnet 9 is inserted into and mounted on the iron core 8, the positioning portion 15 collides with the side end of the iron core 8 to determine the position of the permanent magnet 9 with respect to the iron core 8.

In such a construction, the electric motor is manufactured by forming the shaft 7 into a predetermined shape and size through steps such as cutting, punching electromagnetic steel plates into a predetermined shape and laminating the iron core 8
To produce. Then, a plastic magnet is molded to form a permanent magnet 9, and the permanent magnet rotor 6 is assembled in the state shown in FIG. Further, as shown in FIG. 3, after the permanent magnet 9 is attached to the iron core 8 at a predetermined position, the protrusion 10 is plastically deformed to the end of the iron core by using the iron 14 as shown in FIG. The fixed portion 12 is formed. At this time, the permanent magnet 9 has a positioning portion 15 having a size larger than that of the groove 11 of the iron core 8 formed at one end where the fixing portion 12 is not formed, and the iron core 8 and the positioning portion 15 are abutted against each other. By forming the fixing member 12 at a predetermined position by means of a predetermined position, the assembling accuracy in the axial direction is obtained.

Since the permanent magnet 9 is formed of a plastic magnet, the fixing portion 12 is easily plastically deformed and deformed to a larger extent than the cross section of the groove 11 when heated to about 160 degrees by a soldering iron 14 or the like. Further, the plastic deformation of the protrusion 10 is not limited to the soldering iron 14 and
Any other means may be used as long as it can be heated to such a degree that it is softened by heat, and for example, heating with ultrasonic waves or high frequencies is also possible. It suffices that such protrusions 10 have good balance with respect to rotation, and they may be evenly arranged in the circumferential direction, and at least two protrusions 10 may be provided at opposing positions. The protrusion 10 may be formed only on one side in the axial direction as shown in this embodiment, or the protrusion 10 may be formed instead of the positioning portion 15.

The permanent magnet rotor 6 assembled in this way
Since the permanent magnet 9 is inserted and mounted on the outer periphery of the iron core 8,
Since the outer circumference of the iron core 8 and the inner circumference of the permanent magnet 9 are directly fitted to each other, the amount of eccentricity with respect to the shaft 7 becomes extremely small. Therefore, the gap formed between the stator 3 and the permanent magnet rotor 6 can be made extremely small, and the operating efficiency can be improved in spite of using a plastic magnet, which generally has a low magnetic flux density. it can.

If such a permanent magnet 9 is constructed so as to have an inner diameter fitted to the outer circumference of the iron core 8 and an outer diameter opposed to the inner diameter of the stator 3, the iron core will constitute an electric motor of different output. When the axial thickness is changed by changing the laminated thickness of the stator 8 or the stator 3, only the axial length of the permanent magnet 9 can be changed by a molding die or cutting in the same manner, and therefore the manufacturing is easy. It can be said that there is.

The stator 3 is constructed similarly to a conventional electric motor, and can be manufactured by winding the winding 2 around the stator core 1 and molding the frame 4 by premixing. , The permanent magnet rotor 6 is assembled and integrated by the bracket 13 to complete the process.

[0021]

According to the present invention, the iron core and the permanent magnet are restrained in the rotating direction by fitting the protrusion and the groove, and the fixing portion is formed by the plastic deformation of the protrusion to restrain in the axial direction. Since there is no need to assemble with an adhesive, the air gap formed between the permanent magnet rotor and the stator can be made extremely small, and a motor with high operating efficiency despite using a plastic magnet. Can be configured, and the effect is industrially large.

[Brief description of drawings]

1 is a longitudinal sectional view of an electric motor of the present invention including a permanent magnet rotor.

FIG. 2 is a perspective view of a permanent magnet rotor used in the present invention.

FIG. 3 is a vertical cross-sectional view of a permanent magnet rotor.

FIG. 4 is a perspective view of a main part showing a state in which a permanent magnet rotor is assembled.

FIG. 5 is a vertical cross-sectional view of a main part showing a state in which a permanent magnet rotor is assembled.

[Explanation of symbols]

 1 ……… Stator core 2 ……… Winding 3 ……… Stator 4 ……… Frame 6 ……… Permanent magnet rotor 7 ……… Shaft 8 ……… Iron core 9 ……… Permanent magnet 10… ...... Projection 11 …… Groove 12 …… Fixing part 15 ………… Positioning part

Claims (1)

[Claims] 1. In an electric motor having a permanent magnet rotor, a cylindrical permanent magnet is constituted by a plastic magnet, and a protrusion extending in the axial direction is formed on the inner diameter side of the permanent magnet. A groove that can be fitted is formed on the outer circumference of the iron core, and the axial length of the permanent magnet is increased with respect to the iron core. Further, the permanent magnet is fitted to the iron core, and the axial end portion of the protrusion is formed. An electric motor, characterized in that a permanent magnet rotor is configured by fixing the iron core and a permanent magnet by deforming at a side end of the iron core by plastic deformation, and the permanent magnet rotor is internally provided.