JPH0374151A - Permanent magnet type rotor - Google Patents

Abstract

PURPOSE:To reduce the movement of a permanent magnet piece at the time of filling resin and to improve fluidity of resin by providing protrusions at the terminal strip of the piece, and largely chamfering the inner peripheral corner of the piece disposed in a gap between the pieces. CONSTITUTION:Protrusions 14 protruding between permanent magnet pieces are provided on terminal strips 5a, 6a of a permanent magnet piece 2a. The protrusions 14 are opposed to the linear part 12 of the piece end at the circumferential flat part 15 thus positioning the pieces 2a. The magnet 2a is provided with chamfered parts 11a, 11b at the corners disposed in a gap 8 in order to prevent the pieces from cutting out. The chamfered part 11a of inner periphery is set larger than that 11b of the outer periphery in order to increase the area of the inner periphery of the gap 8. Thus, the fluid resistance of the resin to be filled from resin holes 9a aligned with the protrusions 14 is suppressed to a small value. Thus, the movement of the piece at the time filling the resin is reduced, and the fluidity of the resin is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a permanent magnet rotor of an electric motor that drives, for example, a compressor.

[Prior art]

Permanent magnet rotors (hereinafter referred to as rotors) used in compressors, etc., are made by laminating multiple donut-shaped thin iron plates with a shaft hole in the center to form a thick-walled cylindrical yoke. A plurality of arc-shaped permanent magnet pieces are arranged in an annular manner on the outer periphery, the outer periphery of each permanent magnet piece is covered with a non-magnetic cylinder, and both axial ends of each permanent magnet piece are covered with a ring-shaped non-magnetic It is covered by an end plate.

Conventionally, as disclosed in Japanese Unexamined Patent Publication No. 58-151855, the end plates are formed by die-casting aluminum or the like, and the gaps around each permanent magnet piece are simultaneously filled with die-casting material to form a rotor. However, there is a problem in that eddy currents are generated in the die-cast material that has entered the parts of the rotor during operation of the motor, significantly deteriorating the characteristics of the motor.

As an alternative to the above configuration, for example, JP-A-61-27
The structure disclosed in Publication No. 3154 uses caulking bolts to fix the thin iron plates of the yoke to each other, and also fixes separately formed end plates to the yoke. Thus, a rotor with excellent motor characteristics can be constructed. A general example of a rotor that uses this locking structure is shown in Section 4.
To explain based on the figure and FIG. 5, l is a yoke, 2 is a permanent magnet piece, 3 is a non-magnetic cylinder, 5 and 6 are end plates formed of non-magnetic metal, 4 is the yoke 1 and the end plate It is a caulking pin that penetrates 5 and 6 and is caulked. Reference numeral 7 denotes protrusions of the yoke that are provided equidistantly on the outer periphery of the yoke 1, and are used to position the permanent magnet piece 20 in the circumferential direction.

In addition, for the purpose of stably fixing each permanent magnet piece 2, there is a gap 8 between each permanent magnet piece 2, and an end plate 5 between each permanent magnet piece 2.
, 6 openings, etc. (not shown) around the permanent magnet pieces are filled with resin 17, and resin injection holes 9 and gas vent holes 10 are provided in the end plates 5 and 6. [Problem to be Solved by the Invention] In the rotor configured as described above, each permanent magnet piece 2 is injected and hardened by injection molding or the like. tends to move instantaneously and irregularly in the circumferential direction, and as a result, among the gaps 8 between the permanent magnet pieces, the resin does not adhere well to the areas where the cross-sectional area is small and the flow resistance is extremely large. Put it away. A void portion 18 is formed in the poor gap 8 around the resin, which reduces the fixing strength of the rotor and reduces the reliability in terms of quality.

The protrusion 7 provided on the yoke mentioned above exists to position each permanent magnet piece 20 in the circumferential direction, but the reason why the circumferential position of each permanent magnet piece is not determined is due to the size of the permanent magnet piece. This is due to the large variation and the inability to increase the protrusion dimension of the protrusion 7.

In other words, fired products such as ferrite magnets, which are often used as permanent magnet pieces, have poor finishing accuracy, so the width of the protrusion 7 is naturally set taking into account the maximum dimension of the permanent magnet piece, and this result is In most cases, there will be a considerable gap between the projection 7 of the yoke and the permanent magnet piece 2, in which the permanent magnet piece can move in the circumferential direction. Furthermore, ferrite magnets are mechanically fragile, so they are prone to chipping, especially at the corner parts.
As shown in the figure, it is necessary to provide a chamfered portion 11 in the shape of a straight line or an arc, and variations in the dimensions of the chamfered portion 11 also expand the gap in which the permanent magnet piece can move. .

In contrast, by increasing the protrusion dimension of the protrusion 7 of the yoke,
If circumferential positioning is performed using the linear portions 12 at the circumferential ends of each permanent magnet piece, the effects of dimensional variations in the chamfered portions 11 can be avoided, but the projections 7 of the yoke are made of iron. Therefore, leakage of magnetic flux generally occurs via this protrusion 7. Therefore, increasing the protrusion dimension of the protrusion 7 will further promote the leakage of magnetic flux and significantly degrade the performance of the motor. It is.

Furthermore, by fixing each permanent magnet piece to the yoke l or cylinder 3 with adhesive before resin injection, it is possible to prevent the permanent magnet pieces from moving during resin injection, but in this case, the number of manufacturing steps increases. This would result in a significant increase in cost and is not a practical method.

[Means to solve the problem]

The present invention provides an end plate that covers both ends of the permanent magnet pieces in the axial direction, and includes a protrusion that protrudes between the permanent magnet pieces, and a resin hole that communicates with the gap between the permanent magnet pieces that is maintained by the protrusion. The corner portions of each permanent magnet piece facing the gap between the permanent magnet pieces are chamfered more on the inner diameter side than on the outer diameter side.

[Effect]

By having the protrusion provided on the end plate facing the linear portion of the circumferential end of each permanent magnet piece, a gap of a predetermined width is reliably formed between the permanent magnet pieces, and each permanent magnet facing this gap is The area of the gap is enlarged by chamfering the inner corner of the piece, and the resin holes arranged in parallel with the projections communicate with the gap, thereby suppressing the flow resistance of the resin injected through the resin holes. It will be done.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

In FIGS. 1 and 2, la is a yoke, which is formed into a thick cylindrical shape by laminating a plurality of doughnut-shaped thin iron plates having a shaft hole 13 in the center. 2a is an arc-shaped permanent magnet piece made of a ferrite magnet, etc., and the yoke 1a
A plurality of them are arranged in an annular shape around the outer periphery of the . 3 is a non-magnetic cylinder such as a stainless steel tube, which is fitted onto the permanent magnet piece 2a. 5a and 6a are ring-shaped end plates that cover both axial ends of the permanent magnet piece 2a, and are die-cast in advance from a soft non-magnetic metal such as zinc.

Reference numeral 4 denotes a caulking pin that passes through the yoke 1a and the end plates 5a, 6a, and thereby integrates each component.

The end plates 5a, 6a are provided with the same number of protrusions 14 as the permanent magnet pieces 2a, which are arranged equidistantly and protrude between the respective permanent magnet pieces. This protrusion 14 is integrally formed with the end plates 5a, 6a by die-casting, and as shown in FIG. Each permanent magnet piece 2a is positioned by facing the straight portion 12 at the circumferential end of the permanent magnet piece. Therefore, the permanent magnet pieces 2a are designed so that at least a gap 8 equal to the width of the protrusion 14 is formed between each permanent magnet piece 2a. In addition, resin holes 9a, 9b are formed in the end plates 5a, 6a.
are arranged in parallel on the inside of each projection 14, and these resin holes penetrate the end plate and open into the gap 8 between the permanent magnet pieces.

Further, each permanent magnet piece 2a is provided with a chamfered portion 11a, llb at the corner facing the gap 8 to prevent chipping of the permanent magnet piece, and a chamfered portion 11b on the outer diameter side thereof.
The area of the inner periphery of the gap 8 is expanded by chamfering the chamfered portion 11a on the inner diameter side to a larger extent. In this case, the chamfer width is set to the minimum width necessary to prevent the permanent magnet piece from being chipped at the chamfered portion 11b on the outer diameter side, and
In a, from the viewpoint of the strength of the permanent magnet piece, it is appropriately set to less than half the radial thickness of the permanent magnet piece. Note that the chamfered portions 11a and llb are not limited to the straight cut shape shown in the drawings, but may be formed in an arc shape.

And the permanent magnet pieces 2a such as the gap 8 between each permanent magnet piece.
The gaps around the parts are filled with resin 17 to fix each part. For example, in the case of a rotor used in a compressor, a refrigerant-resistant resin such as PP5 (polyphenylene sulfide) resin is used as the resin, and resin holes 9a or 9b are provided in the end plates 5a and 6a, respectively. It is injected and cured by injection molding using the inlet.

Between the permanent magnet pieces with which the resin holes 9a and 9b communicate,
The gap 8 is maintained by the protrusion 14, and the chamfered portion 11a on the inner diameter side of the permanent magnet piece expands the area of the portion of the gap 8 that faces the resin holes 9a, 9b, so that the required resin flow path is maintained. is ensured, and there are no locations where flow resistance is extremely large. As a result, for example, the resin injected from the resin hole 9a fills the minute gap between each permanent magnet piece 2a and the end plate 5a, and at the same time fills each gap 8 and reaches the opposite end plate 6a. Permanent magnet piece 2a and end plate 6a
Fill the tiny gap between the At this time, since the resin holes 9b of the end plate 6a are also filled with the resin 17, the resin 17 filling the resin holes 9b can be visually observed from the outside of the end plate 6a, and the quality of the resin filling can be confirmed.

〔Effect of the invention〕

According to the present invention, since the protrusion is provided on the end plate of the non-magnetic material, the protrusion is arranged so that the protrusion faces the straight part of the circumferential end of each permanent magnet piece, without causing magnetic flux leakage. Since the permanent magnet pieces are positioned and are not affected by dimensional variations in the chamfered portions of the corners of the permanent magnet pieces, there is less movement of the permanent magnet pieces in the circumferential direction during resin filling, and the permanent magnet pieces are A stable gap is maintained between the two pieces, and since the resin holes that communicate with the gap are arranged side by side on the inside of the protrusion, the resin injected through the resin holes has a good circulation, and as a result, rotation is prevented. This increases the adhesion strength of the child and improves quality reliability. Furthermore, the reduced movement of the permanent magnet pieces during resin filling contributes to improving the balance of the rotor, and also has the effect of reducing vibrations and the like.

In addition, by greatly chamfering the inner diameter corner of the corner part of each permanent magnet piece facing the gap between the permanent magnet pieces, this large chamfer increases the area of the gap facing the resin hole in the end plate. becomes even better. In addition, since pressure is applied to the inner diameter corner part when resin is injected, the permanent magnet piece is pressed in the outer diameter direction to provide tension to the cylinder and tighten the cylinder firmly, while at the same time cutting the outer diameter. It also has the effect of making it easier.

Since the chamfer on the outer diameter side corner is kept small, the area of the permanent magnet on the side close to the stator is not reduced, making it possible to obtain a gap for resin filling without causing negative magnetic effects. I can do it.

Furthermore, since the resin injected from the resin holes in one end plate fills the resin holes in the other end plate, the resin filled in the resin holes in the other end plate cannot be visually observed from the outside of the rotor. Since it can be confirmed, even if a filling defect occurs, it can be easily identified, and it has the advantage of making quality control easier by speeding up responses such as adjusting injection pressure and molding temperature.

[Brief explanation of drawings]

Figures 1 to 3 show examples of the present invention, Figure 1 is a plan sectional view of a permanent magnet rotor, and Figure 2 is a cross-sectional view of the rotor in Figure 1 taken along the P-QR line. 3 is a perspective view of the end plate, 4 and 5 show conventional examples, 4 is a plan sectional view of a permanent magnet rotor, and 5 is the one shown in 4. FIG. 2 is a front sectional view taken along the line ABC. 1, la... yoke, 2, 2a... permanent magnet piece, 3
... Cylindrical body, 4... Crimping bin, 5.5a, 6.6a
...End plate, 8...Gap between permanent magnet pieces, 14.
...Protrusion, 16...Caulking pin through hole, 17...
resin. 1 figure

Claims (3)

[Claims] (1) A plurality of permanent magnet pieces are arranged in an annular manner around the outer circumference of the yoke, the outer circumference of the permanent magnet piece is covered by a cylinder, and both axial ends are covered by end plates, and the gaps around the permanent magnet pieces are covered. In a permanent magnet rotor filled with resin, the end plate has a protrusion projecting between the permanent magnet pieces, and a resin hole communicating with the gap between the permanent magnet pieces maintained by the protrusion. A permanent magnet type rotor, characterized in that the corner portion of each permanent magnet piece facing the gap between the permanent magnet pieces is chamfered more on the inner diameter side than on the outer diameter side. (2) The permanent magnet rotor according to claim 1, characterized in that resin holes are provided inside the protrusions of the end plates. (3) The resin according to claim 1 or 2, characterized in that the resin injected from the resin hole in one end plate fills the resin hole in the other end plate to such an extent that the resin is visually visible. Permanent magnet rotor.