JPH07322576A - Manufacture of permanent magnet rotor - Google Patents

Abstract

PURPOSE:To transmit the torque sufficiently by a structure wherein the protruding parts, provided on the outer peripheral surface of a shaft, provide a uniform gap between a permanent magnet and the shaft and an adhesive is injected uniformly into the gap to prevent the waste of the adhesive. CONSTITUTION:A plurality of protrusions 23, each having an acute tip, are provided at a substantially constant interval on the outer periphery of a magnet fixing part where a permanent magnet 1 is fitted over a shaft 2. The diameter connecting the tips of protrusions 23 is set slightly longer than the inner diameter of the permanent magnet 1. When the permanent magnet 1 and the shaft 2 are assembled, the shaft 2 is press fitted in the permanent magnet 1. The tip of each protrusion 23 is crushed by the inner periphery of the permanent magnet but the root of each protrusion 23 is intact thus providing a uniform gap G over the entire periphery between the outer peripheral surface of the shaft 2 and the inner peripheral surface of the 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 method for manufacturing a permanent magnet type rotor of a rotary electric machine, and more particularly to a method for fixing a shaft and a permanent magnet.

[0002]

2. Description of the Related Art Conventionally, when a hollow cylindrical permanent magnet is fixed to the outer circumference of a rotor shaft, the permanent magnet 1 of the shaft 2 is positioned to position the permanent magnet 1 and the shaft 2 as shown in FIG. 3, for example. An injection groove 22 extending in the axial direction is provided on the outer periphery of a magnet fixing portion 21 for fixing the permanent magnet 1 and the shaft 2 to the positioning jig 3. next,
In the gap G between the permanent magnet 1 and the shaft 2, the injection groove 22
A method of injecting the adhesive 4 via the adhesive is adopted. The positioning jig 3 is provided so that the permanent magnet 1 can be smoothly inserted.
The permanent magnet 1 includes a magnet holding portion 31 having an inner diameter slightly larger than the outer diameter thereof, and a shaft holding portion 32 for holding the shaft end of the shaft 1 concentrically with the permanent magnet 1.

[0003]

However, in the prior art, the permanent magnet 1 is inserted into the shaft 2 and positioned by the positioning jig 3, and the gap between the outer circumference of the shaft 2 and the inner circumference of the permanent magnet 1 is increased. However, a slight gap is created between the outer periphery of the permanent magnet 1 and the inner periphery of the magnet holding portion 31 of the positioning jig 3, so that the permanent magnet 1 is slightly filled in the magnet holding portion 31. It was sometimes biased. Further, since the shaft 2 is held at the shaft end portion, the shaft 2 may be slightly tilted, and the central portion of the shaft 2 where the permanent magnet 1 is fixed to the shaft 2 may be eccentric with respect to the permanent magnet 1. Therefore, it is difficult to uniformly maintain the gap between the permanent magnet 1 and the shaft 2, the adhesive is partially scraped off, the gap is not sufficiently filled with the adhesive, and a uniform adhesive layer is formed. Therefore, there is a problem that sufficient torque cannot be transmitted from the permanent magnet to the shaft. An object of the present invention is to manufacture a permanent magnet type rotor which can maintain a uniform gap between a shaft and a permanent magnet, can be filled with an adhesive without waste, and can transmit a sufficient torque.

[0004]

In order to solve the above problems, the present invention provides a method for manufacturing a permanent magnet rotor in which a hollow cylindrical permanent magnet is fixed to the outer periphery of a shaft, wherein the permanent magnet of the shaft is A plurality of ridges extending in the axial direction are provided on the outer periphery of the magnet fixing portion to be fixed at substantially equal intervals in the circumferential direction, the tips of the ridges are formed at acute angles, and the diameter connecting the tips is the permanent one. It is formed to be slightly larger than the inner diameter of the magnet, the shaft is press-fitted inside the permanent magnet, and an adhesive is filled in a gap formed between the shaft and the permanent magnet.

[0005]

When the permanent magnet is pushed into the shaft by the above means, the protrusions provided at the outer circumferential surface of the shaft at substantially equal intervals in the circumferential direction form substantially uniform gaps, so that they are injected through the injection groove. The adhesive can form an adhesive layer having a substantially uniform thickness.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a plan sectional view showing an embodiment of the present invention, and FIG. 2 is a side sectional view thereof. In the figure, a hollow cylindrical permanent magnet 1 is attached to the outer circumference of a magnet fixing portion 21 inserted into the shaft 2.
A plurality of ridges 23 extending in the axial direction and having a sharp tip are provided at substantially equal intervals in the circumferential direction. The diameter connecting the tips of the protrusions 23 is slightly larger than the inner diameter of the permanent magnet 1. Incidentally, a plurality of injection grooves 22 extending in the axial direction are provided on the outer peripheral surface of the shaft 2 into which the permanent magnets 1 are inserted at substantially equal intervals in the circumferential direction as in the conventional example. When assembling the permanent magnet 1 and the shaft 2, the shaft 2 is press-fitted inside the permanent magnet 1. At this time, the tip of each protrusion 23 is crushed by the inner circumference of the permanent magnet 1, but the root portion of each protrusion 23 maintains its shape, so that the outer peripheral surface of the shaft and the inner peripheral surface of the permanent magnet 1 are Between them, a uniform gap G can be formed over almost the entire circumference. Permanent magnet 1 and shaft 2
Attach the shaft to the positioning jig in the assembled state, and
When the adhesive is injected from the injection groove 22 formed in the above, the adhesive flows along the injection groove 22 and the ridge portion 23, and the uniform gap G is filled with the adhesive, so that the adhesive having a uniform thickness is bonded. Layers can be formed.

[0007]

As described above, according to the present invention, the ridge portion provided on the outer peripheral surface of the shaft forms a substantially uniform gap between the permanent magnet and the shaft, so that the adhesive injected into the gap is bonded. The thickness of the agent becomes uniform, filling the adhesive without waste,
There is an effect that a permanent magnet type rotor capable of transmitting a sufficient torque can be manufactured.

[Brief description of drawings]

FIG. 1 is a plan sectional view showing an embodiment of the present invention.

FIG. 2 is a side sectional view showing an embodiment of the present invention.

FIG. 3 is a side sectional view showing a conventional example.

[Explanation of reference numerals] 1 permanent magnet, 2 shaft, 21 magnet fixing part, 22
Injection groove, 23 ridge,

Claims (1)

[Claims] 1. A method for manufacturing a permanent magnet rotor in which a hollow cylindrical permanent magnet is fixed to the outer circumference of a shaft, wherein a plurality of axially extending outer circumferences of a magnet fixing portion of the shaft to which the permanent magnet is fixed are provided. Inside of the permanent magnet, the ridges are provided at substantially equal intervals in the circumferential direction, the tips of the ridges are formed with an acute angle, and the diameter connecting the tips is formed slightly larger than the inner diameter of the permanent magnet. A method for manufacturing a permanent magnet rotor, wherein the shaft is press-fitted into the shaft, and an adhesive is filled in a gap formed between the shaft and the permanent magnet.