JP2000166136A - Electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily assemble a permanent magnet by positioning a permanent magnet in a circumferential direction being extended between adjacent permanent magnets in a circumferential direction from an end face in the axial direction of the permanent magnet. SOLUTION: In a motor that is provided with a case incorporating a rotor where a coil is wound around a plurality of slots and a stator 3 consisting of four permanent magnets 4 and has a DC brush that can be mounted by a bracket 5 made of resin, four magnet retention parts 13 for retaining the permanent magnets 4 at the bracket 5 while being extended in an axial direction are integrated into the bracket 5. Then, by engaging the permanent magnets 4 between the magnet retention parts 13, the outer-periphery surface of the permanent magnets 4 is retained at the outer-periphery side of the magnet retention parts 13, thus simplifying the assembly operation of the permanent magnets 4 and at the same time reducing the number of parts of a member for positioning the permanent magnets 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to holding a permanent magnet in an electric motor, and more particularly to a motor in which a permanent magnet is disposed on an outer peripheral side of a rotor.

[0002]

2. Description of the Related Art As a conventional technique, Japanese Utility Model Publication No.
There is a technique disclosed in Japanese Patent Laid-Open No. 0-206. FIG. 9 is a view showing holding of a permanent magnet described in the above publication. In this technique, projections 41 are provided at regular intervals in the circumferential direction of the inner peripheral surface of the fixed frame 40, and a positioning member 50 is fitted to the projections 41 and fixed to the inner surface of the fixed frame 40. A technique for mounting a permanent magnet 51 between the 50 is disclosed.

According to this technique, there is provided a stator for a magnet-type rotary electric machine which can easily obtain a rotary electric machine in which a permanent magnet 51 can be easily mounted, has high positioning accuracy, and whose characteristics do not change during operation. You can do it.

[0004]

However, in the above prior art, when assembling the permanent magnet 51 and the positioning member 50, the positioning member 50 is attached to the inner peripheral surface of the fixed frame 40 in advance, and then the permanent magnet 51 is assembled. Therefore, when assembling the permanent magnet 51, the locking portion 50b of the positioning member 50 may be in the way. Further, since the positioning member 50 is mounted on the inner peripheral surface of the fixed frame 40, the mounting direction is increased by the number of the positioning members 50, which is not preferable from the viewpoint of the mounting operation. Further, the positioning member 5
There is a problem that the number of parts increases because a plurality of 0s are required.

Accordingly, an object of the present invention is to provide an electric motor which can be easily assembled and has a small number of parts in order to solve the above problems.

[0006]

According to a first aspect of the present invention, there is provided a rotor having a coil wound around a plurality of slots projecting radially with respect to a rotation axis; An electric motor which is provided on the outer peripheral side of the stator and has a plurality of permanent magnets arranged in the circumferential direction, and a case in which the stator and the rotor are housed, and which can be attached to a mounting portion by a resin bracket. The bracket extends from the axial end face of the permanent magnet to the circumferentially adjacent permanent magnets to position the permanent magnet in the circumferential direction, and integrally includes a magnet holding portion forming a part of the stator. To have.

According to the first aspect, it is possible to assemble the permanent magnet by a simple operation of merely fitting the permanent magnet between the magnet holding portions of the bracket, and a complicated process for assembling the permanent magnet is unnecessary. And is preferred. Further, in the present invention, it is not necessary to provide an extra member for holding the permanent magnet, which is preferable from the viewpoint of reducing the number of parts.

According to a second aspect of the present invention, in the first aspect, the circumferential end of the permanent magnet has a curved surface, and the circumferential end of the magnet holding portion of the bracket presses the outer peripheral surface of the permanent magnet against the inner peripheral surface of the case. That is, the curved surface of the permanent magnet is supported in the direction in which the permanent magnet is formed.

According to the second aspect, the permanent magnet is pressed against the inner peripheral surface of the case by the magnet holding portion.
It is preferable that the position of the permanent magnet does not shift after assembling.

According to a third aspect of the present invention, in the first aspect, irregularities are formed on the contact surface between the axial end of the permanent magnet and the bracket so as to correspond to each contact surface.

According to the third aspect of the present invention, since the unevenness is provided, the position of the permanent magnet does not shift after assembly,
It is suitable.

According to a fourth aspect of the present invention, in the electric motor according to the first or third aspect, unevenness is formed on a contact surface of the magnet holding portion with the permanent magnet.

According to the fourth aspect, when the permanent magnet is fitted between the magnet holding portions, the permanent magnet is pressed into between the magnet holding portions to crush the irregularities, so that the permanent magnet is firmly attached to the magnet holding portion. It is preferable that the position of the permanent magnet does not shift after being fixed and assembled.

[0014]

Embodiments of the present invention will be described with reference to the drawings. 1 to 6 show views of the electric motor 1 according to the first embodiment. FIG. 1 is a cross-sectional view of the electric motor 1 according to the first embodiment, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIGS. FIG. 5 and 6
FIG. 3 is a diagram showing a main part of the present embodiment.

The electric motor 1 has thirteen slots 10 protruding in the radial direction of the rotation axis, a rotor 2 having a coil 11 wound around each slot 10 and rotating together with the output shaft 9,
A stator 3 comprising four permanent magnets 4 arranged on the outer peripheral side of the rotor 2 and having N and S poles alternately formed on the surface on the rotor 2 side, and the stator 3 and the rotor 2 are internally mounted. This is a DC brushed motor including a metal case 6 and a resin bracket 5 for mounting the electric motor 1.

The electric motor 1 according to the first embodiment
Is used for an actuator which is arranged in a transfer (not shown) and switches between two-wheel drive and four-wheel drive of the vehicle. The rotation of the rotor 2 rotates the gear meshing with the output shaft 9 so that the two-wheel drive From 4 wheel drive or 4 wheel drive from 2
Switching to wheel drive is performed.

The bracket 5 which is the gist of the present invention will be described. The bracket 5 is made of a synthetic resin material and has flexibility. The bracket 5 is provided with four magnet holding portions 13 extending in the axial direction and holding the permanent magnets 4 integrally with the bracket 5, so that the permanent magnets 4 are held between the magnet holding portions 13. It is configured. The end of the magnet holding portion 13 has a shape corresponding to the curved surface of the end of the permanent magnet 4. Before the electric motor 1 is assembled, the arc formed by the end of the adjacent magnet holding portion 13 is formed by the permanent magnet 4.
Is shorter than the inner circumferential side arc of.

The operation of the electric motor 1 will be briefly described. When the commutator 8 attached to the output shaft 9 and the brush 7 attached to the bracket 5 come into contact with each other, the coil 11 through which current flows is defined, and current is supplied from a battery (not shown) via the brush 7. Then, a current flows through a predetermined coil 11. When a current flows through the coil 11, the slot 1 around which the coil 11 through which the current flows is wound.
When 0 forms a magnetic pole, a magnetic attraction force or a magnetic repulsion force acts between the permanent magnet 4 and the permanent magnet 4, and a force acts in a direction in which the rotor 2 rotates. When the rotor 2 rotates, the commutator 8 in contact with the brush 7 changes, so that the energized coil 11 also changes with the rotation of the rotor 2. Therefore, the slot 10 in which the magnetic attraction force and the magnetic repulsion force act with the permanent magnet 4 changes with the rotation of the rotor 2, and the rotor 2
Rotates continuously.

The assembly of the electric motor 1 will be described. First, the coil 11 is wound around the slot 10 and the rotor 2
Is formed, the commutator 8 is attached to the rotor 2, and then the rotor 2 is attached to the bracket 5 along the magnet holding portion 13. The bracket 5 and the rotor 2 are supported by ball bearings. Next, the permanent magnet 4 is fitted between the magnet holding portions 13 along the magnet holding portions 13. At this time, as shown in FIG. 5, the outer peripheral surface of the permanent magnet 4 is held on the outer peripheral side of the outer peripheral surface of the magnet holding portion 13. And the magnet holder 13
The case 6 is put on the outer periphery of the permanent magnet 4. Here, since the inner periphery of the case 6 is smaller than the circumference formed by the outer peripheral surface of the permanent magnet 4 before the case 6 is assembled, each permanent magnet 4 is indicated by an arrow by the end of the magnet holding portion 13 as shown in FIG. It is assembled in the case 6 while being pressed radially outward as shown. By the assembly of the case 6, the end of the rotor 2 is supported by a thrust bearing. Then, after the case 6 is assembled, the case 6 and the bracket 5 are fixed at three places by screws 12, and the electric motor 1 is attached to the actuator. If the bracket 5 is formed integrally with the housing (not shown) of the actuator, the assembly to the actuator can be omitted.

According to the first embodiment, the rotor 2, the permanent magnet 4, the case 6, and the screw 12 are assembled by one-way assembly, so that the operation of assembling the electric motor 1 is simplified. Further, since the member for positioning the permanent magnet 4 is constituted by the magnet holding portion 13 formed integrally with the bracket 5, the number of components does not increase.

Next, a second embodiment of the present invention will be described. FIG. 7 shows a perspective view of the bracket 25 according to the second embodiment.

In the second embodiment, the abutment surfaces of the bracket 25 and the permanent magnet in the axial direction are formed with irregularities.
A is provided with a recess (not shown) on the contact surface on the permanent magnet side. With this configuration, when the permanent magnet is fitted between the magnet holding portions, the concave portion and the convex portion 25A are engaged, and the permanent magnet is securely fixed to the bracket 25, and the displacement of the permanent magnet after the electric motor is assembled is suppressed. Can be. Other configurations and operations are the same as those of the above-described first embodiment, and a description thereof will be omitted.

Next, a third embodiment of the present invention will be described. FIG. 8 is a perspective view of the bracket 35 according to the third embodiment.

In the third embodiment, irregularities 36 A are formed at the end of the magnet holding portion 36. According to this configuration, when the permanent magnet is fitted between the magnet holding portions, the permanent magnet is press-fitted between the magnet holding portions 36 to crush the irregularities 36A, and the permanent magnet is firmly fixed to the magnet holding portion 36. The displacement of the permanent magnets after the electric motor is assembled can be suppressed. Other configurations and operations are the same as those of the above-described first embodiment, and a description thereof will be omitted.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and any type of electric motor can be used as long as it is an electric motor according to the gist of the present invention. It may be a motor.

[0026]

According to the first aspect of the present invention, the permanent magnet can be assembled by a simple operation of merely fitting the permanent magnet between the magnet holding portions of the bracket, and a complicated process for assembling the permanent magnet is achieved. It is unnecessary and suitable. Further, in the present invention, it is not necessary to provide an extra member for holding the permanent magnet, which is preferable from the viewpoint of reducing the number of parts.

According to the second aspect, the permanent magnet is pressed against the inner peripheral surface of the case by the magnet holding portion.
It is preferable that the position of the permanent magnet does not shift after assembling.

According to the third aspect, since the unevenness is provided, the position of the permanent magnet does not shift after assembly,
It is suitable.

According to the fourth aspect, when the permanent magnet is fitted between the magnet holding portions, the permanent magnet is press-fitted between the magnet holding portions to crush the irregularities, so that the permanent magnet is firmly attached to the magnet holding portion. It is preferable that the position of the permanent magnet does not shift after being fixed and assembled.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electric motor according to a first embodiment.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a perspective view of a bracket of the electric motor according to the first embodiment.

FIG. 4 is a perspective view when a permanent magnet is fitted into the bracket.

FIG. 5 is a diagram showing a main part of the present embodiment.

FIG. 6 is a diagram showing a main part of the present embodiment.

FIG. 7 is a perspective view of a bracket of an electric motor according to a second embodiment.

FIG. 8 is a perspective view of a bracket of an electric motor according to a third embodiment.

FIG. 9 is a diagram showing fixing of a permanent magnet in the prior art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electric motor 2 ... Rotor 3 ... Stator 4 ... Permanent magnet 5, 25, 35 ... Bracket 6 ... Case 7 ... Brush 8 ... Commutator 9. ..Output shaft 10 ... Slot 11 ... Coil 12 ... Screw 13, 36 ... Magnet holding part

Claims (4)

[Claims] 1. A rotor having coils wound around a plurality of slots projecting radially with respect to a rotation axis, and a plurality of permanent magnets formed on an outer peripheral side of the rotor and arranged in a circumferential direction. An electric motor comprising: a stator comprising: a stator and a rotor; and a case in which the stator and the rotor are housed. An electric motor, wherein a permanent magnet extending between adjacent permanent magnets in the circumferential direction for positioning the permanent magnets in the circumferential direction and integrally forming a part of the stator is integrally provided. 2. A circumferential end of the permanent magnet has a curved surface, and a circumferential end of the magnet holding portion of the bracket has a shape in which the outer circumferential surface of the permanent magnet is pressed against the inner circumferential surface of the case. The electric motor according to claim 1, wherein the electric motor supports a curved surface. 3. The electric motor according to claim 1, wherein the contact surface between the axial end of the permanent magnet and the bracket is formed with irregularities corresponding to the respective contact surfaces. 4. The electric motor according to claim 1, wherein an uneven surface is formed on a contact surface of the magnet holding portion with the permanent magnet.