JP2004236366A - Permanent magnet type motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost permanent magnet type motor which is equipped with a rotor where permanent magnets fixed around its stacked iron core by means of an adhesive is hard to exfoliate even at high-speed revolution and besides which is structuralized to have favorable magnetic properties. <P>SOLUTION: In the permanent magnet type motor which has a rotor 1 where a plurality of segment type permanent magnets 4 are fixed at equal intervals around its stacked iron core 3 by means of an adhesive 6, the rotor iron core 3 possesses pin-shaped claws 5, and the permanent magnets 4 are pressed by bending the claws 5 after adhesion of the permanent magnet 4. Hereby, the permanent magnet type motor which is high in stability and reliability can be materialized, by preventing the adhesive exfoliation of the permanent magnets 4 in the high-speed rotating permanent magnet type motor. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a permanent magnet type motor using segmented permanent magnets divided in a circumferential direction, and more particularly to a permanent magnet fixing structure for a rotor.
[0002]
[Prior art]
2. Description of the Related Art In recent years, high-speed rotation of a permanent magnet type motor has been desired in accordance with high functionality and high productivity of devices equipped with a permanent magnet type motor such as robots and machine tools.
In the conventional permanent magnet type motor, as shown in FIG. 3, a plurality of segment type permanent magnets 4 are fixed to the outer periphery of the laminated rotor core 3 fitted to the outer periphery of the rotating shaft 2 with an adhesive 6. The stator 1 was configured.
However, as the speed of the permanent magnet motor increases, the centrifugal force increases due to the high-speed rotation of the rotor, and the thermal deterioration of the adhesive due to the rise in temperature may cause the permanent magnet fixed to the rotor core to peel off and fall off. there were. On the other hand, in order to prevent adhesion and separation of the permanent magnet, the permanent magnet is covered with a cylindrical cover body (for example, Patent Document 1), or a segment-shaped permanent magnet is filled with a resin material to integrally form the permanent magnet. Various devices such as a molding method have been devised.
[0003]
[Patent Document 1]
JP-A-6-284650
[Problems to be solved by the invention]
However, such conventional techniques have a problem that manufacturing is troublesome and costly. It is also conceivable to form a slit-shaped groove in the rotor core and insert the end of the segment-shaped permanent magnet into the groove to suppress centrifugal separation.However, the end of the permanent magnet may be replaced with the rotor core. There is a problem that the magnetic flux leakage becomes large because of the covering.
The present invention has been made in order to solve such a problem, and a structure in which a permanent magnet fixed to an outer periphery of a laminated rotor core with an adhesive is not easily separated even at high speed rotation and has good magnetic properties. It is an object of the present invention to provide an inexpensive permanent magnet type motor having a rotor having the above configuration.
[0005]
[Means for Solving the Problems]
In order to solve the above problem, the present invention provides a permanent magnet type motor in which a plurality of segment type permanent magnets are fixed at equal intervals to the outer periphery of a laminated rotor core using an adhesive to form a rotor. , A pin-shaped claw is provided on the rotor core, and after the permanent magnet is bonded, the claw is bent to hold down the permanent magnet.
ADVANTAGE OF THE INVENTION According to this invention, permanent magnet adhesion peeling is prevented in a high-speed rotation permanent magnet type motor, and a highly stable and reliable permanent magnet type motor can be realized. In addition, since magnetic properties of iron deteriorate due to the application of mechanical stress, the magnetic flux leaking from the nail is reduced by bending the iron. Further, the nail for holding down the permanent magnet also functions as a jig for holding the permanent magnet until the adhesive hardens, so that the work of bonding the permanent magnet can be performed efficiently.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
This is an embodiment relating to the first and second aspects of the present invention. In this embodiment, an 8-pole permanent magnet type motor will be described as an example.
FIGS. 1A and 1B are views showing a rotor of a permanent magnet type motor according to a first embodiment of the present invention, wherein FIG. 1A is a front sectional view, and FIG. 1B is a view seen from the direction of arrow A in FIG. . The rotor 1 includes a rotating shaft 2, a rotor core 3, and a segment-shaped permanent magnet 4. As the material of the rotor core 3, a silicon steel plate of S60 is used. This silicon steel plate was punched out with a circular mold having at least one pin-shaped claw-shaped hole, and one steel plate was punched out so that the interval between the claws 5 matched the interval between the gaps between the permanent magnets 4. Each time, the laminate was rotated at a mechanical angle of 45 °. In this manner, the rotor core 3 having the pin-shaped claws 5 protruding from eight locations can be formed by one mold.
Next, after the rotating shaft 2 is press-fitted into the rotor core 3, a heat-curable epoxy-based adhesive 6 is applied to the outer periphery of the rotor core 3. Thereafter, eight neodymium-based permanent magnets 4 are arranged at equal intervals between the claws 5, and the claws 5 are bent to press down the permanent magnets 4 from both sides. Since the claw 5 also plays the role of a jig for holding the permanent magnet 4, it is put into a furnace in this state, and the adhesive is cured by heating at an appropriate temperature for an appropriate time.
The permanent magnet type motor having the rotor 1 manufactured in this manner and a general permanent magnet type motor fixing the segment type permanent magnets 4 only with an adhesive as shown in FIG. A destructive test was performed in which the number of revolutions was gradually increased until scattered. As a result, no scattering of the permanent magnet was observed even at a rotation speed 2N twice as high as the rotation speed N of the permanent magnet of the general permanent magnet type motor.
In the permanent magnet type motor of the present invention, since one or two pin-shaped claws 5 are pressed on both sides of the permanent magnet 4 in addition to the adhesive, the peeling of the permanent magnet 4 can be more firmly prevented. it can.
The maximum magnetic flux density of each permanent magnet 4 of the permanent magnet type motor of the present invention was measured using a Gauss meter. As a result, the maximum magnetic flux density was M, which was not different from the maximum magnetic flux density M of the permanent magnet not held by the claws, and no leakage of magnetic flux was observed. However, when the number of claws 5 for holding down the permanent magnet 4 was increased to five on one side, the maximum magnetic flux density was found to be 0.9 M, a decrease of 10%. Therefore, in order for the permanent magnet type motor to have good magnetic characteristics, one or two pin-like claws 5 are desirable.
[Second embodiment]
This is an embodiment according to the third aspect of the present invention. In this embodiment, an 8-pole permanent magnet type motor will be described as an example.
2A and 2B are diagrams showing a rotor of a permanent magnet type motor according to a second embodiment of the present invention, wherein FIG. 2A is a front sectional view, and FIG. 2B is a diagram viewed from the direction of arrow B in FIG. .
The rotor 1 includes a rotating shaft 2, a rotor core 3, and a segment-shaped permanent magnet 4. As the material of the rotor core 3, a silicon steel plate of S60 is used. This silicon steel plate is punched out by a circular mold having eight pin-shaped claw holes at equal intervals, and one sheet is provided on each outer side of a rotor core 3 in which steel sheets punched by a circular mold having no claws are laminated. A steel plate having claws 5 is laminated. By doing so, the rotor core 3 with the pin-shaped claws 5 protruding from eight locations on both outer sides can be formed.
Next, after the rotating shaft 2 is press-fitted into the rotor core 3, a heat-curable epoxy-based adhesive 6 is applied to the outer periphery of the rotor core 3. After that, eight neodymium-based permanent magnets 4 are arranged at regular intervals so that the claws 5 substantially hit the center of the permanent magnets 4, and the claws 5 are bent to press down the permanent magnets 4 from both sides. Since the claw 5 also plays the role of a jig for holding the permanent magnet 4, it is put into a furnace as it is, and the adhesive is cured by heating at an appropriate temperature for an appropriate time.
The permanent magnet type motor having the rotor 1 manufactured as described above and a general permanent magnet type motor fixing the segment type permanent magnet 4 only with an adhesive as shown in FIG. A destructive test was performed in which the number of revolutions was gradually increased until scattering. As a result, no scattering of the permanent magnet was observed even at a rotation speed 2N twice as high as the rotation speed N of the permanent magnet of the general permanent magnet type motor. In the permanent magnet type motor according to the present invention, since both sides of the permanent magnet 4 are pressed by the pin-shaped claws 5 in addition to the adhesive, the peeling of the permanent magnet can be more firmly prevented.
The maximum magnetic flux density of each permanent magnet 4 of the permanent magnet type motor of the present invention was measured using a Gauss meter. As a result, the maximum magnetic flux density was M, which was not different from the maximum magnetic flux density M of the permanent magnet 4 not held by the claw 5, and no leakage of magnetic flux was observed. However, when the shape of the claw 5 for holding down the permanent magnet 4 was not a pin but a plate having a width of 5 mm, the magnetic flux density was found to be 0.9 M, a decrease of 10%. Therefore, in order for the permanent magnet type motor to have good magnetic characteristics, a pin-like claw having a small width is desirable.
[0007]
【The invention's effect】
As described above, the present invention has the following effects.
(1) Since the permanent magnets are fixed together with the adhesive by pressing the segment-shaped permanent magnets with pin-shaped claws provided on the laminated iron core, the permanent magnets are peeled off in a high-speed rotating permanent magnet type motor. Thus, a permanent magnet type motor having high stability and high reliability can be realized.
(2) Since the claws that press the segment-shaped permanent magnets also serve as jigs for holding the permanent magnets until the adhesive hardens, the permanent magnets can be bonded efficiently.
[Brief description of the drawings]
FIGS. 1A and 1B are diagrams showing a rotor of a permanent magnet type motor according to a first embodiment of the present invention, wherein FIG. 1A is a front sectional view and FIG. 1B is a diagram viewed from the direction of arrow A in FIG. .
FIGS. 2A and 2B are views showing a rotor of a permanent magnet type motor according to a second embodiment of the present invention, wherein FIG. 2A is a front sectional view and FIG. 2B is a view as seen from the direction of arrow B in FIG. .
FIG. 3 is a front sectional view showing a rotor of a permanent magnet type motor according to the related art.
[Explanation of symbols]
1: rotor 2: rotating shaft 3: rotor core 4: segment-shaped permanent magnet 5: pin-shaped claw 6: adhesive

Claims (3)

In a permanent magnet type motor in which a rotor is formed by fixing a plurality of segment type permanent magnets on an outer periphery of a laminated rotor core at equal intervals using an adhesive,
A permanent magnet type motor comprising: a rotor core having pin-shaped claws; and bending the claws to hold down the permanent magnets after bonding the permanent magnets. 2. The permanent magnet type motor according to claim 1, wherein after the permanent magnet is adhered, both ends of the permanent magnet in the rotation direction are pressed by the claws. 2. The permanent magnet type motor according to claim 1, wherein the pawl presses both ends of the permanent magnet in the axial direction after the permanent magnet is bonded.

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