JPH09308149A - Internal magnet type motor and its permanent magnet fixing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of parts and lower the manhour in work by providing two ring-shaped magnet fixing members with press-fitting parts, circumferential pressers, and axial pressers. SOLUTION: Since a permanent magnet 2 is fixed inside the insertion hole 11 of a rotor core 1 by means of a circumferential presser 55 and an axial presser 55 by pushing one face of a magnet fixing member 5 against both end faces of a rotor core 1, and adding pressure to a magnetic flux leakage preventive hole 12 thereby inserting it, the permanent magnet 2 can be fixed without an adhesive. Therefore, the permanent magnet 2 can be fixed to the rotor core 2 merely by pressing a magnet fixing member 5 molded integrally to the rotor core 1, so such a problem as the instability of the quality accompanying the bonding work and the increase of the manhour in work can be dissolved. Moreover, heating facilities for using a thermosetting adhesive and an carrying in and takeout device become needless, so the automation of the manufacturing facilities becomes easy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner magnet type motor having a permanent magnet for forming a field in a cylindrical rotor and a method for fixing the permanent magnet.

[0002]

2. Description of the Related Art Conventionally, as shown in, for example, FIGS. 4 and 5, a rotor of an internal magnet type motor has a cylindrical rotor core 1 at an equal pitch in the circumferential direction and in the axial direction of the same number as the number of poles. An insertion hole 11 having a quadrangular cross section is provided, the permanent magnets 2 having the quadrangular cross section and the same number as the number of motor poles are mounted therein, and the magnetic flux leakage prevention holes 12 are provided between the adjacent insertion holes 11. Is disclosed (for example, Japanese Patent Application Laid-Open No. 5-76146). In this case, in order to fix the permanent magnet 2 in the insertion hole 11 of the rotor core 1 with high heat resistance, a thermosetting adhesive is applied to the surface of the permanent magnet 2 and the permanent magnet 2 is inserted into the insertion hole 11 and then a predetermined amount is applied. The adhesive is hardened by heating at a temperature for a predetermined time so that an adhesive force can be generated between the rotor core 1 and the permanent magnet 2 to withstand the generated torque. Further, when the rotor is balanced, it is difficult to fix the balance weight directly to the rotor core 1 with a mounting screw or the like because the rotor core 1 is formed by laminating thin steel plates. Therefore, as shown in FIGS. 5A and 5B, the balance disc 31 is fixed to the shaft 3 fixed to the rotor core 1 by shrink fitting, and the balance weight 4 is attached to the balance disc 31 with an attaching screw. It was

[0003]

However, in the above-mentioned prior art, when the permanent magnet coated with the adhesive is inserted into the insertion hole, the adhesive is rubbed and scraped off around the insertion hole,
There was a problem that sufficient adhesive did not adhere to the inner surface of the permanent magnet and the insertion hole, resulting in a decrease in strength due to lack of adhesive material, instability of quality due to variations in bonding work, and increase in man-hours. . Furthermore, since a thermosetting adhesive is used, a heating facility for heating for a long period of time and a loading / unloading device for the heating facility are required, and there has been a problem that automation of the manufacturing facility costs much. Also, since the balance disc is fixed to the shaft by shrink fitting,
There is a problem that the tolerance when machining the outer diameter of the shaft and the inner diameter of the balance disc must be strictly controlled, tapping for mounting screws, etc. is required, which requires a large number of parts and a large number of machining steps. It was SUMMARY OF THE INVENTION It is an object of the present invention to provide an inner magnet type motor having a small number of parts and a reduced number of working steps, and a permanent magnet fixing method for the same.

[0004]

In order to solve the above problems, the present invention provides a cylindrical rotor core formed by laminating thin steel plates, and a number of poles provided in the rotor core at equal pitches in the circumferential direction. In the inner magnet type motor having the same number of axially extending insertion holes, magnetic flux leakage prevention holes provided between the adjacent insertion holes, and permanent magnets fixed in the insertion holes, the magnetic flux A shaft that is inserted between the press-fitting portion that protrudes in the axial direction and that can be pressed into engagement with the leakage prevention hole and the permanent magnet and the inner surface of the insertion hole, and that is in contact with the permanent magnet with a tapered surface. It is provided with two ring-shaped magnet fixing members provided with a circumferential pressing portion projecting in the direction and an axial pressing portion projecting in the axial direction. Further, the magnet fixing member is integrally molded by resin molding with the press-fitting portion, the circumferential pressing portion, the axial pressing portion, and a plurality of weight fixing projections provided at equal intervals in the circumferential direction. It has been done. Further, the press-fitting portion has a large number of small protrusions provided on the outer surface. Further, in a cylindrical rotor core formed by laminating thin steel plates, there are insertion holes extending in the axial direction at the same pitch as the number of poles in the circumferential direction, and magnetic flux leakage provided between the adjacent insertion holes. In the method of fixing a permanent magnet of an inner magnet type motor in which a prevention hole is provided and a permanent magnet is fixed in the insertion hole, an axially protruding press-fitting portion that can be pressed and engaged with the magnetic flux leakage prevention hole, A circumferential pressing portion that is inserted between the permanent magnet and the inner surface of the insertion hole and that projects in the axial direction so as to contact the permanent magnet with a tapered surface; and an axial pressing portion that projects in the axial direction. With two ring-shaped magnet fixing members provided with, the permanent magnet is inserted into the insertion hole, and then the press-fitting portion of the magnet fixing member is inserted into the magnetic flux leakage prevention hole from both end surfaces of the rotor core. , The circumferential pressing portion to the permanent magnet It is inserted between the inner surface of the insertion hole and the magnet fixing member is pressed against both end surfaces of the rotor core to fix the permanent magnet to the rotor core by the circumferential pressing portion and the axial pressing portion. It is a thing. Further, a plurality of weight fixing protrusions are projected on the magnet fixing member at equal intervals in the circumferential direction,
The balance weight is fixed to any of the fixing protrusions.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 is a front view showing a rotor of an embodiment of the present invention, a part of which is shown in cross section. In the figure, reference numeral 1 denotes a cylindrical rotor core formed by laminating thin steel plates, which is fixed to a shaft 3. Reference numeral 11 denotes an insertion hole provided in the rotor core 1 at an equal pitch in the circumferential direction and having a quadrangular cross section extending in the same axial direction as the number of poles, and 2 denotes a quadrangular cross section installed in the insertion hole 11 and a motor pole. The same number of permanent magnets, 12
Is a magnetic flux leakage prevention hole provided between the adjacent insertion holes 11. The width of the insertion hole 11 is made larger than the width of the permanent magnet 2, and a pressing portion 11a is provided in the insertion hole 11 to which the permanent magnet 2 is pressed and positioned. Reference numeral 5 is a magnet fixing member integrally molded with a molding resin in a ring shape having an outer diameter slightly smaller than the outer diameter of the rotor core 1. One surface 51 is adapted to be in close contact with both end surfaces of the rotor core 1 and the other surface. The ring-shaped balance weight 4 is fixed to the ring 52 by projecting a plurality of weight fixing protrusions 53 at equal intervals in the circumferential direction. The method of fixing the balance weight 4 is as follows. After the weight fixing projection 53 is put into the balance weight 4, the weight fixing projection 5 is inserted.
3 may be welded, or a push nut may be fitted into the weight fixing protrusion 53.

Reference numeral 54 denotes a press-fitting portion having the number of poles axially projected on one surface 51 of the magnet fixing member 5 so that it can be inserted into the magnetic flux leakage prevention hole 12 provided in the rotor core 1 in the circumferential direction. Are provided at equal intervals, and as shown in FIG.
The outer surface of 4 is provided with a large number of small protrusions 54a.
Reference numeral 55 denotes a circumferential pressing portion axially protruding from one surface 51 of the magnet fixing member 5, which is designed to be inserted between the permanent magnet 2 and the inner side surface of the insertion hole 11. The contact surface is inclined in a taper shape, and by pressing the permanent magnet 2 in the axial direction by the circumferential pressing portion 55, the permanent magnet 2 is pressed in the circumferential direction and is pressed against the pressing portion 11a in the insertion hole 11. It is pressed against. Reference numeral 56 denotes an axial pressing portion projecting in the axial direction on one surface 51 of the magnet fixing member 5, and is provided at a position facing the axial end surface of the permanent magnet 2.

When fixing the permanent magnet 2 to the rotor core 1, after inserting the permanent magnet 2 into the insertion hole 11, one surface 51 of the magnet fixing member 5 is pressed against both end surfaces of the rotor core 1, The press-fitting portion 54 is inserted into the magnetic flux leakage prevention hole 12 by applying pressure. At this time, the projection 54a provided on the outer surface of the press-fitting portion 54 bites into and engages with the core sag portion 12a formed by press punching inside the magnetic flux leakage prevention hole 12, so that the magnet fixing member 5 is attached to the end surface of the rotor core 1. Is firmly fixed to. When the rotor core 1 is laminated, half of the entire length is inverted and laminated, so that the core sag portions 12a at both end portions of the rotor core 1 can also bite into and engage with the protrusion 54a.
At the same time, the circumferential pressing portion 55 is inserted between the permanent magnet 2 and the inner surface of the insertion hole 11 and presses the permanent magnet 2 against the pressing portion 11 a in the insertion hole 11, so that the permanent magnet 2 is fixed to the rotor core 1. It is fixed in the insertion hole 11. Finally, the axial pressing portion 56 presses the axial end surface of the permanent magnet 2, and the permanent magnet 2 is axially positioned and fixed. When balancing the rotor, the balance weight 4 may be fixed to the weight fixing projections 53 at arbitrary positions of the magnet fixing member 5 fixed to both end surfaces of the rotor core 1. With such a configuration, one surface 51 of the magnet fixing member 5 is pressed against both end surfaces of the rotor core 1, and the press-fitting portion 54 is inserted into the magnetic flux leakage prevention hole 12 by applying pressure to the circumferential pressing portion 55. Since the permanent magnet 2 is fixed in the insertion hole 11 of the rotor core 1 by the axial pressing portion 56, the permanent magnet 2 can be fixed without an adhesive. Further, since the balance weight 4 is attached to the magnet fixing member 5 that is fixed in close contact with both end surfaces of the rotor core 1,
Since it is not necessary to attach a balance disk separately, the number of parts can be reduced. The magnet fixing member 5
Alternatively, the permanent magnet 2 may be fixed by using a member that is divided into members having the same shape with the press-fitting portion 54 as the center.

[0008]

As described above, according to the present invention, the permanent magnet can be fixed to the rotor core simply by pressing the integrally formed magnet fixing member against the rotor core, so that there is a concern about quality associated with the bonding work. The problems of qualitative and increase of man-hours are solved. Further, since heating equipment for using the thermosetting adhesive and a loading / unloading device for the heating equipment are unnecessary, automation of the manufacturing equipment is facilitated. Further, since the balance weight is attached to the magnet fixing member which is fixed in close contact with both end faces of the rotor core, it is not necessary to attach a balance disk separately, and the number of parts can be reduced. Therefore, there is an effect that it is possible to provide an inner magnet type motor and a permanent magnet fixing method thereof, which has a small number of parts and can reduce the number of work steps.

[Brief description of drawings]

FIG. 1 is a front view showing a rotor according to an embodiment of the present invention.

FIG. 2 is a side sectional view taken along the line AA showing the rotor of the embodiment of the present invention.

FIG. 3 is an enlarged side sectional view of a main part taken along the line BB showing the rotor of the embodiment of the present invention.

FIG. 4 is a side sectional view showing a conventional example.

5 (a) is a front view and FIG. 5 (b) is a side sectional view showing a conventional example.

[Explanation of symbols]

1: rotor core, 11: insertion hole, 11a: pressing part,
12: magnetic flux leakage prevention hole, 12a: core sag, 2: permanent magnet, 3: shaft, balance weight, 5: magnet fixing member, 51: one surface, 52: other surface, 53: weight fixing projection, 54: press fit portion, 54a: protrusion portion, 5
5: Circumferential retainer, 56: Axial retainer

Claims (5)

[Claims] 1. A cylindrical rotor core formed by laminating thin steel plates, insertion holes extending in the axial direction as many as the number of poles provided in the rotor core at equal pitches in the circumferential direction, and the insertions adjacent to each other. In an inner magnet type motor having a magnetic flux leakage prevention hole provided between holes and a permanent magnet fixed in the insertion hole, the magnetic flux leakage prevention hole is projected in an axial direction capable of being engaged by being pressed. A press-fitting portion, a circumferential pressing portion that is inserted between the permanent magnet and the inner surface of the insertion hole, and that projects in the axial direction so as to contact the permanent magnet with a tapered surface, and projects in the axial direction. An inner magnet type motor comprising: two ring-shaped magnet fixing members provided with an axial pressing portion. 2. The magnet fixing member is configured such that the press-fitting portion, the circumferential pressing portion, the axial pressing portion, and a plurality of weight fixing projections provided at equal intervals in the circumferential direction are integrally formed of resin. The inner magnet type motor according to claim 1, which is molded by a mold. 3. The inner magnet type motor according to claim 1, wherein the press-fitting portion has a large number of small protrusions on its outer surface. 4. A cylindrical rotor core formed by laminating thin steel plates is provided between an insertion hole extending in the axial direction at the same number as the number of poles at an equal pitch in the circumferential direction, and between the adjacent insertion holes. In the method of fixing a permanent magnet in an inner magnet type motor, wherein a magnetic flux leakage prevention hole is provided, and a permanent magnet is fixed in the insertion hole, a press fit projecting in the axial direction capable of being pressed and engaged with the magnetic flux leakage prevention hole. Portion, a circumferential pressing portion that is inserted between the permanent magnet and the inner surface of the insertion hole, and that projects in the axial direction so as to contact the permanent magnet with a tapered surface, and an axial direction that projects in the axial direction. After the permanent magnet is inserted into the insertion hole, the press-fitted portion of the magnet fixing member is inserted into the magnetic flux leakage prevention hole from both end surfaces of the rotor core. When inserting, keep the circumferential pressing part The permanent magnet is inserted between the permanent magnet and the inner surface of the insertion hole, the magnet fixing member is pressed against both end surfaces of the rotor core, and the permanent magnet is pressed by the circumferential pressing portion and the axial pressing portion. A method for fixing a permanent magnet in an inner magnet type motor, which is characterized in that: 5. The permanent magnet for an inner magnet type motor according to claim 4, wherein a plurality of weight fixing projections are projected from the magnet fixing member at equal intervals in a circumferential direction, and a balance weight is fixed to any of the fixing projections. Fixing method.