JP2550980Y2 - Motor rotor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a rotor of a permanent magnet type motor having a rotor rotatably disposed inside a stator via a flange and a bearing.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view taken along a line perpendicular to the axis showing an example of a rotor of a conventional motor, and FIG. 6 is a sectional view taken along a BOB. The rotor 10 has a magnetic pole member 11 formed by laminating a plurality of ropes made of a magnetic material formed by punching or the like.
Are fixed by press-fitting, shrink-fitting, bonding, or the like, and a block-shaped magnet 12 is arranged so that the outer circumference of the magnetic pole member 11 is sequentially different. The magnetic pole member 11 and the magnet 12 are sandwiched at both ends by a disk 13, a bolt 14, and a nut 15 made of a non-magnetic material.

[0003] Here, the outer peripheral portion of the magnetic pole member 11 is connected to a stepped surface (dimension L1 in the figure) where adjacent different poles are saturated with a small magnetic flux that is practically acceptable. Further, the inner peripheral portion of the magnetic pole member 11 has a cross section that does not cause stress breakdown even when the same pole (the S pole in the figure) is fitted to the shaft 1, and is connected to the other poles (in the figure, the other poles). The (N-pole) has a magnetically large magnetic resistance due to a gap C1 provided in the radial direction, so that the poles do not magnetically short-circuit with each other (see JP-A-1-144337).

[0004]

In the above-described conventional motor rotor structure, if there is a gap at the joint surface F1 between the magnet 12 and the magnetic pole member 11, this gap becomes a magnetic resistance and contributes to the torque generation of the motor. The effective magnetic flux density decreases, and as a result, the output characteristics of the motor deteriorate. For this reason, it is necessary to make the gap at the joint surface F1 as small as possible. Here, since the magnetic pole member 11 is made by punching a magnetic steel plate by a die press, it can be made relatively accurately. However, since magnets are made by pressing magnetic powder and then sintering the magnet, the dimensional variation is large.
In order to improve the dimensional accuracy of No. 4, it was necessary to grind the magnet, which increased the cost of the motor. Even if the magnet is ground, the magnet 12
In order to insert the magnetic head into the magnetic pole member 11, a small gap is required, which causes the following problem.

[0005] 1) The above-mentioned air gap becomes a magnetic resistance, and the effective magnetic flux density as a motor decreases, and as a result, the output characteristics of the electric motor deteriorate. 2) When the magnet 12 is magnetized, the magnet 12 suddenly moves to a side having a smaller magnetic resistance with the magnetic pole member 11 at the moment of being magnetized. For this reason, there is a risk that the magnet 12 may be broken or partly chipped. Therefore, an operation such as bonding is required to fix the magnet 12 to the magnetic pole member 11, and thus the number of operation steps is increased, resulting in an increase in the cost of the electric motor. The purpose of the present invention is to eliminate the air gap between the magnet and the magnetic pole member, improve the output characteristics of the electric motor, and bond the magnet to the magnetic pole member. An object of the present invention is to provide an electric motor rotor that does not need to perform the above-described operations.

[0006]

According to the present invention, there is provided a magnetic pole member made of a magnetic material, and the magnetic pole member is substantially radially arranged with respect to an axis so that the magnetic pole member has sequentially different poles in a circumferential direction. The present invention relates to a rotor of an electric motor having a block-shaped magnet disposed in
The block-shaped magnet is divided into two or more.
In addition, the joint surface of the magnets has a gradient in the axial
This is achieved by that the divided block-shaped magnets are pushed in the axial longitudinal direction from the axial end face side.

[0007]

[Function] In the present invention, the magnet is divided and the magnets are separated from each other.
Has a shape with a gradient in the axial longitudinal direction ,
By the structure in a state where each other's magnet is always pushed in the axial direction, there is no empty gap between the magnet and the pole members, thereby improving the output characteristics of the motor, for securing the magnet to the pole member This eliminates the need for operations such as bonding.

[0008]

FIG. 1 is a sectional view taken along a line perpendicular to the axis of a first embodiment of a motor rotor according to the present invention, corresponding to FIG. FIG. 2 is a BOB sectional structure diagram of FIG. 1, and FIG. 3 is a perspective view of a magnetic pole member and a magnet. The same components are denoted by the same reference numerals, and description thereof is omitted. In FIG. 1, a magnet 12 arranged in a magnetic pole member 11 is divided into a magnet 12A and a magnet 12B. Here, the respective magnets 12A and 12B are shown in FIG.
As shown in the perspective view of FIG.
D has a gradient with respect to the joining surfaces SA and SB with the magnetic pole member 11, and the magnets 12A and 12B are slightly shifted from each other in the longitudinal direction (about 1 mm to 2 mm in the La dimension in the figure). When superposed, the thickness LM is almost the same as the dimension L4 of the portion of the magnetic pole member 11 into which the magnet is inserted, and the longitudinal dimension Lb of both magnets at that time is:
It is made to be slightly shorter than the axial longitudinal dimension of the insertion part of the pole member 11.

The magnets 12A and 12B thus produced
In the above, for example, the magnet 12B is fixed,
When A is pushed in the direction of Fa in the figure, the magnet 12A moves in the direction of Fb in the figure, and as a result, the magnet width LM increases. The magnets 12A and 12B thus configured are connected to the magnetic pole member 11.
After the magnets 12A and 12B are pushed in the longitudinal direction with the discs 13 attached to both ends of the magnetic pole member 11 in the longitudinal direction, the magnets 12A and 12B spread in the direction of the joint surface F1 with the magnetic pole member 11. The magnet end faces SA and SB can be joined to the magnetic pole member 11 without any gap. As a result, the magnetic resistance between the magnet and the magnetic pole member is reduced, the characteristics of the motor are improved, and the need for bonding or the like for fixing the magnet is not required.

As a means for pushing the magnets 12A and 12B in the longitudinal direction of the shaft, for example, as shown in FIG. 2, a method of screwing a bolt 16 attached to the disk 13 can be considered.
As another example, as shown in FIG.
The leaf spring 17 may be disposed in the gap C2 between the plate spring 17 and the 2A. The same effect can be obtained by using an elastic body such as hard rubber instead of the leaf spring. In this embodiment, the example in which the magnet is divided into two is described, but the magnet may be divided into three or more.

[0011]

As described above, according to the motor rotor of the present invention, the gap between the magnet and the magnetic pole member is eliminated and the magnetic resistance is reduced, so that the characteristics of the motor are improved. Also,
Since an operation such as bonding for fixing the magnet is not required and the number of operation steps is reduced, an inexpensive electric motor can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view at right angles to an axis showing a first example of the rotor of the electric motor of the present invention.

FIG. 2 is a BOB sectional structure diagram of a rotor of the electric motor of FIG. 1;

FIG. 3 is a perspective view showing an example of a magnetic pole member and a magnet of FIG. 1;

FIG. 4 is a cross-sectional view at right angles to the shaft showing a second example of the rotor of the electric motor of the present invention.

FIG. 5 is a cross-sectional view perpendicular to an axis showing an example of a rotor of a conventional electric motor.

FIG. 6 is a BOB sectional structure diagram of a rotor of the electric motor of FIG. 5;

[Explanation of symbols]

 12a, 12b Magnet 16 Screw 17 Leaf spring C2 Air gap

Claims (1)

(57) [Scope of request for utility model registration] 1. A magnetic pole member made of a magnetic material, and a block-shaped member arranged substantially radially with respect to an axis in the magnetic pole member so that the magnetic pole member has sequentially different poles in a circumferential direction. In the rotor of the electric motor having a magnet, the block-shaped magnet is divided into two or more,
The joint surface of the magnets has a gradient in the axial longitudinal direction
A rotor for an electric motor having a shape, wherein the divided block-shaped magnets are pushed into the shaft longitudinal direction from the axial end face side.