JPH0759281A - Rotor with cylindrical permanent magnet of rotating electric machine - Google Patents

Abstract

PURPOSE:To provide a rotor with cylindrical permanent magnet so that no excessive force is applied to a cylindrical permanent magnet during operation. CONSTITUTION:The rotor consists of a first rotor center 3a with an annular projecting part 4 which projects to the outer-diameter side of both edges in side direction being mounted to a rotor shaft 2 and a recessed part 5 over the outer periphery at a central part, a second rotor sensor 3b where both edges in axial direction are supported by the projecting part 4 of the first rotor center 3a and which has the same thermal coefficient of expansion as a cylindrical permanent magnet 1, and the cylindrical permanent magnet 1 which is mounted to the outer-diameter side of the second rotor center 3b, thus reducing the deformation of the second rotor center 3b regardless of thermal expansion and hence preventing an excessive force from being applied to the cylindrical permanent magnet 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor in which a permanent magnet is attached to a rotor shaft of a rotary electric machine.

[0002]

2. Description of the Related Art A rotary electric machine having a rotor with a cylindrical permanent magnet is used as a drive motor for an electric vehicle. FIG. 2 is a sectional view of a conventional rotor with a cylindrical permanent magnet. In a conventional rotary electric machine including a rotor with a cylindrical permanent magnet, a cylindrical permanent magnet 1 and a rotor shaft 2 that holds the magnet are fixed with an adhesive or the like. Since the coefficient of thermal expansion of the rotor shaft 2 is larger than that of the cylindrical permanent magnet 1, the elongation of the rotor shaft 2 becomes larger than that of the permanent magnet 1 due to the temperature rise during operation, and the permanent magnet 1 is inserted from the inside. The force to push and spread is permanent magnet 1
Act on.

[0003]

If the structure supporting the cylindrical permanent magnet of a rotary electric machine equipped with the cylindrical permanent magnet expands and an excessive force is applied to the cylindrical permanent magnet, the cylindrical permanent magnet is damaged. In order to prevent this, it is necessary to suppress the temperature rise in the rotating electric machine during operation. Since the physique of the rotating electric machine can be reduced by increasing the temperature increase in order to generate the same output, reducing the temperature increase is uneconomical because the physique becomes large.

The present invention relates to a rotating electric machine having a rotor having a cylindrical permanent magnet attached to a rotor shaft, and a rotating machine with a cylindrical permanent magnet which prevents an excessive force from being applied to the cylindrical permanent magnet during operation. The purpose is to provide children.

[0005]

In a rotary electric machine equipped with a rotor having a cylindrical permanent magnet on a rotor shaft and a stator facing the rotor, a rotor mounted on the rotor shaft has axially opposite ends. A first rotor center having an annular convex portion projecting to the outer diameter side and a concave portion extending to the outer periphery of the central portion, and both end portions in the axial direction supported by the convex portion of the first rotor center, and the cylindrical permanent body. The above object is achieved by the second rotor center having the same coefficient of thermal expansion as the magnet and the cylindrical permanent magnet attached to the outer diameter side of the second rotor center.

[0006]

According to the present invention, there is provided a first rotor center having projections attached to the rotor shaft and projecting to the outer diameter side at both ends in the axial direction, and a recess extending to the outer periphery of the central portion, and the first rotor center. From the second rotor center, which has the same coefficient of thermal expansion as the cylindrical permanent magnet and whose axial ends are supported on the outer diameter side, and the cylindrical permanent magnet, which is supported on the outer diameter side of the second rotor center. With this configuration, even if the temperature rises along with the rotation, a concave portion is formed in the axially central portion of the first rotor center with high rigidity, so that an excessive force is not applied from the central portion.
Also, since both axial ends of the first rotor center are thinner than the second rotor center in the radial direction, the rigidity is low, and therefore even if the temperature rises, the second rotor center is excessively large. It does not deform. Since the second rotor center has the same thermal expansion as the cylindrical permanent magnet, the permanent magnet receives a pushing force from the first rotor center to the outer diameter side through the second rotor center, but It does not receive excessive force from the rotor center side.

[0007]

1 is a sectional view of a rotor with a cylindrical permanent magnet according to an embodiment of the present invention. In FIG. 1, the same parts as those in FIG. 2 are designated by the same reference numerals. The rotor with a cylindrical permanent magnet according to the present invention includes a rotor shaft 2 having a first rotor center 3a.
Is attached. The first rotor center 3a is provided with a convex portion 4 protruding toward the outer diameter side at both ends in the axial direction, and a concave portion 5 machined in the central portion. First rotor center 3a
The second rotor center 3b having both ends in the axial direction supported by the recess 5 on the outer diameter side and having the same coefficient of thermal expansion as the cylindrical permanent magnet.
Is attached. The cylindrical permanent magnet 1 is attached to the outer diameter side of the second rotor center 3b by adhesion made of epoxy resin. The cylindrical permanent magnet 1 uses, for example, a neodymium sintered magnet, and the second rotor center 3b has an amber (36% N) having the same coefficient of thermal expansion as the neodymium sintered magnet.
i-Fe) is used. By the way, the thermal expansion coefficient of Amber is 1.
It is 1/10 ⁶ , which is about 1/10 of the thermal expansion coefficient of iron. The cylindrical permanent magnet 1 and the second rotor center 3b are bonded with an adhesive material made of epoxy resin, or both are bonded by a key.

When the first rotor center 3a thermally expands due to rotation, the outer periphery of the central portion, which has high rigidity, becomes the recess 5, so that the central portion does not directly push up the second rotor center 3b. . Further, both ends in the axial direction of the first rotor center are annular convex portions 4, and since the radial thickness is thin, the rigidity is low and the second rotor center 3b even if expanded.
Is not pushed up strongly. Since the cylindrical permanent magnet 1 thermally expands by the same amount as the second rotor center 3b and the deformation amount of the second rotor center 3b is small, an excessive force is not applied to the cylindrical permanent magnet 1. .

[0009]

According to the present invention, the first rotor center having a large coefficient of thermal expansion is provided with a concave portion in the central portion having a large rigidity, and the annular convex portions at both axial ends having a small rigidity constitute the second rotor. Support the center. Since the convex portion of the second rotor center has the same coefficient of thermal expansion as the cylindrical permanent magnet, the cylindrical permanent magnet directly applies the force in the outer diameter direction of the first rotor center to the second permanent magnet.
However, since the second rotor center is thin in the radial direction and its deformation is small, the deformation amount of the cylindrical permanent magnet can be reduced. Therefore, the cylindrical permanent magnet is not subjected to an excessive force.

[Brief description of drawings]

FIG. 1 is a sectional view of a rotor with a cylindrical permanent magnet according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional rotor with a cylindrical permanent magnet.

[Explanation of symbols]

 1 Cylindrical permanent magnet 2 Rotor shaft 3a 1st rotor center 3b 2nd rotor center 4 Convex part 5 Recessed part

Claims (1)

[Claims] 1. A rotary electric machine comprising a rotor having a cylindrical permanent magnet on a rotor shaft, and a stator facing the rotor, wherein the rotor shaft is mounted on the rotor shaft and has an outer diameter side at both ends in an axial direction. A first rotor center having a projecting annular convex portion and a concave portion extending to the outer periphery of the central portion, and both ends in the axial direction supported by the convex portion of the first rotor center, and having the same heat as the cylindrical permanent magnet. A rotor with a cylindrical permanent magnet for a rotary electric machine, comprising a second rotor center having an expansion coefficient and a cylindrical permanent magnet mounted on the outer diameter side of the second rotor center. .