JP2001095185A - Rotor of electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to obtain the good manufacturability, high quality and stable characteristics of an electric motor. SOLUTION: A magnet member 11 is formed with a magnetic resin having magnetic anisotropy in such a way that many magnetic pole parts 11a having a shape that projects most at the central part of the stator side are connected integrally annularly. This magnet member 11 is inserted into a yoke member 12 to form the yoke member 12 integrated with the magnet member 11 with a magnetically soft resin. By having such magnet member 11 and yoke member 12, the formation of the magnet member 11, that of the yoke member 12 and the joint of these members are all made possible by forming the resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rotor for an electric motor using a resin magnet.

[0002]

2. Description of the Related Art Conventionally, a rotor for an electric motor has been disclosed in
No. 0-94203 is provided.

FIG. 15 and FIG. 16 show the same, in which a large number of magnet members 1 formed in a substantially rectangular block shape by ferrite having magnetic anisotropy are arranged in a ring shape, and are arranged from the outer periphery to the top. Is covered with an iron frame 2. Further, a ring member 3 is arranged on the outer periphery of the frame 2, and between the outer periphery of the ring member 3 and the ring member 3 and the frame 2, between the frame 2 and each magnet member 1, as well as the magnet net member. The resin 4 is injected and molded between each of the magnet members 1, the magnet member 1, the frame 2, and the ring member 3.
Is integrated.

[0004] Incidentally, this is an outer rotor type electric motor in which the rotor is positioned outside the stator and rotates.
3 shows the structure of a rotor. In this case, the magnet member 1 is finally magnetized.

[0005]

In the case of the above-mentioned conventional device, the ring-shaped arrangement of the magnet members 1 is performed by sequentially arranging a large number of magnet members 1 in a mold (not shown) in a ring shape, but it takes time. And the manufacturability was poor. Also, a magnet member 1 arranged in a ring shape
In addition, it takes time and effort to cover the frame 2 thereafter, and the manufacturability is poor.

Further, the magnet member 1 made of ferrite is fragile, and the magnet member 1 may be cracked by a hit when the frame 2 is put on the magnet member 1 or a pressure when the resin 4 is injected and molded. Was difficult to get high. Although a large number of magnet members 1 are arranged in a ring shape and integrated with the resin 4, because of the large number of the magnet members 1, the dimensions, particularly the diameter on the stator side (in the example of the outer rotor type electric motor described above, It is difficult to obtain the precision of the inner diameter, and it is difficult to stably obtain the characteristics of the electric motor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is therefore an object of the present invention to provide a motor having a high manufacturability, a high quality, and a stable motor characteristic. In providing the child.

[0008]

In order to achieve the above object, in the rotor of the electric motor of the present invention, first, the central portion on the stator side is most protruded by the magnetic resin having magnetic anisotropy. A magnet member formed such that a number of magnetic pole portions having the following shape are connected in an integrated ring shape, and this magnet member is inserted into the magnet member by being molded with a soft magnetic resin. The yoke member is provided (the invention of claim 1). According to this, the formation of the magnet member,
The formation of the yoke members and their connection are all performed by molding the resin.

In the rotor of the electric motor according to the present invention, the second
A magnet member formed by a magnetic resin having magnetic anisotropy so that a plurality of magnetic pole portions having a shape in which the central portion on the stator side is the most protruding is formed so as to be connected to an integral arc, and a plurality of the magnet members are provided. The magnet member is inserted and molded with a soft magnetic resin in a state where the magnet member is arranged in a single ring, and a yoke member integrated with the magnet member is provided. (The invention of claim 2). According to this method as well, the formation of the magnet member, the formation of the yoke member, and their connection are all performed by molding of resin.

In the rotor of the electric motor according to the present invention, the third
A magnet member formed by a magnetic resin having magnetic anisotropy such that a plurality of magnetic pole portions having a shape in which the central portion on the stator side is the most convex are formed so as to be connected in an integrated arc, and this magnet member is inserted. And a yoke member integrated with the magnet member by being molded with a soft magnetic resin, and a plurality of integrated members of the magnet member and the yoke member are arranged in one ring shape. (Invention of claim 3). This also allows the formation of a magnet member and
The formation of the yoke members and their connection are all performed by molding the resin.

In these cases, in addition to the magnet member and the yoke member described above, it is preferable to provide a frame member integrated with the magnet member and the yoke member by inserting them and molding them with a resin. In this case, further, the formation of the frame member and the joining of the frame member to the magnet member and the yoke member are accurately performed by molding the resin.

It is preferable that a yoke component made of a magnetically permeable metal is provided on the side of the magnet member opposite to the stator (the invention of claim 5). In this device, the magnetic properties are improved by the yoke component, and the strength is also improved.

Further, the yoke member is preferably formed in the recess at the boundary between the magnetic pole portions of the magnet member such that the yoke member is located on the side opposite to the stator from the most stator side portion of the magnetic pole portion. invention). In this case, the connection between the magnet member and the yoke member is made stronger without impairing the magnetic characteristics.

In addition, on the stator side of the magnet member,
Preferably, the frame member is formed so as to surround the magnetic pole portion with a predetermined thickness (the invention of claim 7). In this case, the connection between the magnet member and the yoke member and the frame member is further strengthened, and the air gap between the stator and the stator is secured more reliably.

It is preferable that the yoke member is formed on the upper and / or lower portions of the magnet member together with the outer and / or inner peripheral portions of the magnet member (the invention of claim 8). In this case, the connection between the magnet member and the yoke member is further strengthened.

Further, it is preferable to form a resin passage at the magnetic pole boundary of the magnet member.
In this case, the yoke member extending over the inner and outer peripheries of the magnet member can be more reliably formed.

Preferably, a part of the yoke member is protruded from the frame member covering the yoke member, and the protruding portion is magnetized with a greater number of magnetic poles than the magnetic pole portion of the magnet member. In this case, more magnetic poles for detecting the rotational position are obtained than the magnetic pole portion of the magnet member.

In addition, the number of molding gates of the magnet member and the yoke member may be the same as or half of the number of the magnetic pole portions of the magnet member, and may be set near the center of the magnetic pole portion and molded (claim 11). . In this one,
As the flow of the magnetic resin matches the direction of magnetization,
Polar anisotropy, which is advantageous in terms of magnetic characteristics, can be achieved.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention applied to a rotor of an outer rotor type electric motor will be described below with reference to FIGS. First, in FIG.
Reference numeral 11 denotes a magnet member, which is formed into a ring shape by using a magnetic resin having a magnetic powder mixed with a synthetic resin as a binder, in particular, a magnetic resin having magnetic anisotropy. Have. In this case, NdFeB, SmFeN, or SmCo is used as the magnetic powder.

Each of the magnetic pole portions 11a has a bulge shape in which the inner side on the stator side is the most convex at the center.
The magnet member 11 is formed by linking a large number of these in an integrated ring shape. As a result, each boundary portion of the magnetic pole portion 11a has a concave shape, while the magnet member 11
The entire outer peripheral surface is a smooth surface without irregularities.

On the other hand, reference numeral 12 denotes a yoke member, which is formed by inserting the magnet member 11 on the inner and outer peripheries thereof by using a soft magnetic resin. It is integrated into. In this case, the outer portion 12a of the yoke member 12 has a ring shape surrounding the entire magnet member 11, and the inner portion 12b has the magnetic pole portion 1 of the magnet member 11.
1a is located in a recess at each boundary.

Further, in this case, the magnet member 11
As shown in FIG. 2, the inner portion 12b of the magnet member 11 is located on the outer peripheral surface side opposite to the stator by a dimension A from the top of the inner peripheral surface which is the most stator side of each magnetic pole portion 11a of the magnet member 11. It is shaped to be. After this configuration, a frame (not shown) is integrated with the yoke member 12. Further, the magnetic pole portion 11a of the magnet member 11 is subjected to necessary magnetization so as to function as a rotor of the electric motor. Further, at this time, the magnetic anisotropy of the magnetic resin from which the magnet member 11 is formed is made to exhibit magnetic permeability in the radial direction. In addition, the motor having the rotor of the present configuration is used as a driving motor for rotating, for example, an agitator or a tub of a washing machine.

Now, according to the above configuration,
Formation of the magnet member 11, formation of the yoke member 12,
In addition, all of these connections are made by molding of resin, and since there is no need for troublesome arrangement of a large number of magnet members 1 such as a conventional one and covering of the frame 2, the productivity is improved. can do.

The magnet member 11 and the yoke member 12 formed by molding the resin in this manner do not crack during the manufacturing process unlike the conventional magnet member 1 made of ferrite. Obtainable.

Further, since the magnet member 11 and the yoke member 12 formed by molding the resin are unlikely to cause an assembly error as in the case where a large number of conventional magnet members 1 are arranged in a ring shape, the dimensions, especially the stator side (The inner diameter in the case of the outer rotor type electric motor described above) can easily be accurate, and thereby the characteristics of the electric motor can be stably obtained. Moreover, the magnet member 11 and the yoke member 12 formed by molding the resin are light and can contribute to the weight reduction of the entire electric motor. In addition, the thermal expansion coefficient is almost the same, and the generation of cracks due to temperature change And so on.

In addition, in the case of the above configuration, the yoke member 12 is formed on the inner and outer circumferences of the magnet member 11,
Thereby, the connection between the magnet member 11 and the yoke member 12 can be made stronger, and the dimensional accuracy can be further increased. Moreover, in this case, the inner portion 12b of the yoke member 12 is provided in the recess at the boundary between the magnetic pole portions 11a of the magnet member 11,
Since the molding is performed so as to be positioned on the side opposite to the stator from the part on the most stator side of a, the magnetic characteristics are not impaired.

While the first embodiment of the present invention has been described above, FIGS. 3 to 13 show the second to first embodiments of the present invention.
In this example, the same portions as those in the first example are denoted by the same reference numerals, and description thereof will be omitted. Only different portions will be described.

[Second Embodiment] In the second embodiment shown in FIGS. 3 and 4, instead of the above-described ring-shaped magnet member 11, an arc-shaped magnet member 21 obtained by dividing the ring-shaped magnet member into a plurality of equal parts is used. have. This magnet member 2
Reference numeral 1 denotes a magnetic resin having the same magnetic anisotropy as that of the above-described magnet member 11, which is formed such that a plurality of (three in the illustrated example) magnetic pole portions 21a corresponding to the magnetic pole portions 11a are connected in an integrated arc shape. It is.

As shown in FIG. 4, a plurality of (four in the illustrated example) magnet members 21 are arranged in a ring shape (not shown), and the magnet members 21 are inserted. By shaping the yoke member 12 with a soft magnetic resin, the yoke member 12 is integrated with the magnet member 21, and simultaneously, the plurality of magnet members 21 are integrated with the yoke member 12.

Also in this case, the formation of the magnet member 21, the formation of the yoke member 12, and the joining thereof can all be performed by molding the resin.
The same operation and effect as the embodiment can be obtained. In this case, since the size of the magnet member 21 is smaller than that of the ring-shaped magnet member 11, the molding can be easily performed.

[Third Embodiment] In the third embodiment shown in FIGS. 5 and 6, instead of the above-described ring-shaped magnet member 11 and yoke member 12, they are equally divided into a plurality. It has an arc-shaped magnet member 31 and a yoke member 32. Of these, the magnet member 3
Reference numeral 1 denotes a magnetic resin having the same magnetic anisotropy as that of the above-described magnet member 11 and molded so that a plurality of (three in the illustrated example) magnetic pole portions 31a corresponding to the magnetic pole portions 11a are connected in an integrated arc shape. The yoke member 32 is formed on the inner and outer periphery of the yoke member 32 by the same magnetic resin as the yoke member 12 as shown by the outer portion 32a and the inner portion 32b.

As shown in FIG. 6, a plurality (four in the illustrated example) of the magnet member 31 and the yoke member 32 are arranged in a single ring (not shown). By inserting the magnet member 31 and the yoke member 32 and molding the frame member 33 with resin, the frame member 33 is integrated with them, and at the same time, the integrated product of the plurality of magnet members 31 and the yoke member 32 is 33 are integrated.

Also in this case, the formation of the magnet member 31, the formation of the yoke member 32, and the joining thereof can be accurately performed by molding the resin, so that the same operation and effect as in the first embodiment can be obtained. be able to.
Further, in this case, not only the size of the magnet member 31 but also the size of the yoke member 32 can be made smaller than the above-mentioned ring-shaped magnet member 11 and yoke member 12, so that they can be easily formed. In this case, the frame member 33 may be manufactured separately from the integrated product of the magnet member 31 and the yoke member 32, and may be assembled and integrated therewith.

[Fourth Embodiment] In the fourth embodiment shown in FIG. 7, the magnet member 11 and the yoke member 12 described above are used.
In addition, a frame member 41 is provided, and the frame member 41 includes a magnet member 11 and a yoke member 12.
Are molded with resin on the outer periphery and above thereof, and are integrated with the magnet member 11 and the yoke member 12 by the molding. Note that the frame member 41 has a shaft cylinder portion 41 for attaching a shaft (not shown).
a is formed at the center.

In this manner, in addition to the formation of the magnet member 11, the formation of the yoke member 12, and the connection thereof, the formation of the frame member 41, the frame member with respect to the magnet member 11 and the yoke member 12, Since the bonding up to 41 can be performed with high precision by molding the resin, the manufacturability can be further improved, and the dimensional accuracy can be further increased, so that the characteristics of the electric motor can be more stably obtained. Further, in this case, including the frame member 41, it is possible to further contribute to the weight reduction of the entire electric motor, and it is possible to prevent the occurrence of cracks due to a change in temperature, etc., including the frame member 41.

[Fifth Embodiment] In a fifth embodiment shown in FIG. 8, a yoke component 51 made of a magnetically permeable metal is disposed on the side of the magnet member 11 opposite to the stator, and furthermore,
The outer portion 12a of the yoke member 12 is formed and integrated with the outer periphery thereof. In this case, the yoke component 51 improves the magnetic characteristics and also improves the strength.

[Sixth Embodiment] In a sixth embodiment shown in FIG. 9, the frame member 41 of the fourth embodiment is provided on the stator side of the magnet member 11 with the magnetic pole portion 11a having a predetermined thickness B.
(At the top portion of the magnetic pole portion 11a, for example, 1 [mm] or less, up to 0.3 [mm]). In this manner, the connection between the magnet member 11 and the yoke member 12 and the frame member 41 can be further strengthened, and the air gap between the stator and the stator (not shown) can be secured more reliably. I can do it.

[Seventh Embodiment] In the seventh embodiment shown in FIG. 10, the lower portion 12c and the upper portion are provided not only on the outer and inner peripheral portions of the magnet member 11, but also on the lower and upper portions of the magnet member 11. As shown by the portion 12d, the yoke member 12 is formed. By doing this,
The connection between the magnet member 11 and the yoke member 12 can be further strengthened. In this case, the yoke member 1
2 may be formed only on one of the upper part and the lower part of the magnet member 11.

[Eighth Embodiment] In an eighth embodiment shown in FIG. 11, a missing portion 61 as a resin passage is formed at the boundary of the magnetic pole portion 11a of the magnet member 11. By doing so, the flow of the resin (hot water) over the inner and outer peripheries of the magnet member 11 is made smooth by the lacking portion 61, so that the yoke member 12 can be formed more reliably. In this case, the missing portion 61
The magnet member 11 may be formed on the entire boundary portion of the magnetic pole portion 11a, or may be formed on some of them.

Ninth Embodiment In the ninth embodiment shown in FIG. 12, a part of the yoke member 12 is made to protrude from the frame member 41 which covers the yoke member 12, and the protruding portion 12e is made to project from the magnetic pole portion 11a of the magnet member 11. Magnetization with a large number of magnetic poles. In this way, more magnetic poles for detecting the rotational position can be obtained than the magnetic pole part 11 of the magnet member 11 by magnetizing the yoke member 12 (the protruding portion 12e). Can be.

[Tenth Embodiment] In a tenth embodiment shown in FIG.
(Injection molding) gates 71, 72 of the same number as the magnetic pole portion 11a of the magnet member 11 or half thereof (half in the illustrated example) are set near the center of the magnetic pole portion 11a. I have.

By doing so, the flow of the magnetic resin for molding the magnet member 11 and the yoke member 12 respectively, as shown by the arrows in the figure,
1 and the direction of magnetization of the magnetic pole portion 11a is matched with
An extremely anisotropic magnetic property can be obtained, and the characteristics of the electric motor can be improved.

FIG. 14 shows an example in which the molding gates 71 and 72 of the magnet member 11 and the yoke member 12 are formed by setting the number to less than half the number of the magnetic pole portions 11a of the magnet member 11. In this case, the flow of the magnetic resin is in the circumferential direction of the magnet member 11 in a portion C near the molding gate 71, and the magnetic pole portion 11
Since it does not match the direction of magnetization of a, the pole anisotropy, which is advantageous in terms of magnetic characteristics, cannot be performed, and the characteristics of the electric motor cannot be improved.

Although the first to tenth embodiments of the present invention have been described above, the present invention is not limited to them, and one of them is that the whole rotor is positioned outside the aforementioned stator and rotates. The inner rotor is not limited to the one that rotates, and may be one that is positioned inside the stator and rotates (inner rotor). Further, the equipment using the electric motor is not limited to a washing machine, but may be a clothes dryer or the like. Furthermore, the yoke member does not need to be on the inner and outer circumferences of the magnet member, but may be, for example, only on the outer circumference (non-stator side).

Further, the configuration of the fourth to tenth embodiments is not limited to the configuration of the first embodiment, but may be adopted in the configuration of the second embodiment or the configuration of the third embodiment. Is also good. In addition, the present invention can be appropriately modified and implemented without departing from the gist.

[0046]

The present invention is as described above.
The following effects are obtained. According to the rotor of the electric motor of the first aspect, since the formation of the magnet member, the formation of the yoke member, and the connection thereof are all performed by molding of resin, the manufacturability can be improved, and the quality can be improved. Further, the characteristics of the electric motor can be obtained stably, and further, it is possible to contribute to weight reduction of the entire electric motor, and it is possible to prevent occurrence of cracks due to a change in temperature.

According to the rotor of the motor of the second aspect, the formation of the magnet member, the formation of the yoke member, and the coupling thereof can all be performed by molding the resin. Similar functions and effects can be obtained. In this case, since the size of the magnet member is smaller than the ring-shaped magnet member, it can be easily formed.

According to the third aspect of the present invention, the formation of the magnet member, the formation of the yoke member, and the coupling thereof can be accurately performed by molding the resin. The same operation and effect as the child can be obtained. In this case, not only the size of the magnet member but also the size of the yoke member can be made smaller than that of the ring-shaped magnet member and the yoke member, so that they can be easily formed.

According to the rotor of the motor of the fourth aspect, since the formation of the frame member and the joining of the frame member to the magnet member and the yoke member are precisely performed by molding the resin, the productivity is further improved. In addition to being able to improve, the dimensional accuracy can be made higher, and the characteristics of the electric motor can be more stably obtained.
It is possible to further contribute to the weight reduction of the entire electric motor including the frame member, and it is possible to prevent the occurrence of cracks due to a change in temperature and the like including the frame member.

According to the rotor of the motor according to the fifth aspect, the magnetic properties can be improved by the yoke component disposed on the side opposite to the stator of the magnet member, and also the strength can be improved. Can be. According to the rotor of the electric motor of the sixth aspect, the coupling between the magnet member and the yoke member can be made stronger without deteriorating the magnetic characteristics. According to the rotor of the electric motor of the seventh aspect, the connection between the magnet member and the yoke member and the frame member can be further strengthened, and the air gap between the stator and the stator can be secured more reliably. Can be.

According to the rotor of the electric motor of the eighth aspect, the connection between the magnet member and the yoke member can be further strengthened. According to the rotator of the electric motor of the ninth aspect, the flow of the resin over the inner and outer peripheries of the magnet member can be smoothly performed by the resin passage, so that the yoke member can be more reliably formed.

According to the rotor of the electric motor of the tenth aspect, the number of magnetic poles for detecting the rotational position can be obtained more than the magnetic pole portion of the magnet member by magnetizing the protruding portion of the yoke member. Rotation position can be detected. According to the rotor of the electric motor of the eleventh aspect, since the flow of the magnetic resin for molding the magnet member and the yoke member respectively matches the direction of magnetization of the magnet member, the polar anisotropy is advantageous in terms of magnetic characteristics. Thus, the characteristics of the electric motor can be improved.

[Brief description of the drawings]

FIG. 1 is an overall cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a portion D in FIG. 1;

FIG. 3 is a cross-sectional view of a single magnet member showing a second embodiment of the present invention.

FIG. 4 is a diagram corresponding to FIG. 1;

FIG. 5 is a cross-sectional view of a magnet member and a yoke member according to a third embodiment of the present invention.

FIG. 6 is a diagram corresponding to FIG. 1;

FIG. 7 is a longitudinal sectional view of a half showing a fourth embodiment of the present invention.

FIG. 8 is a view corresponding to FIG. 2, showing a fifth embodiment of the present invention;

FIG. 9 is a view corresponding to FIG. 2, showing a sixth embodiment of the present invention.

FIG. 10 is a view corresponding to FIG. 7, showing a seventh embodiment of the present invention;

FIG. 11 is a partially enlarged perspective view of a magnet member according to an eighth embodiment of the present invention.

FIG. 12 is a view corresponding to FIG. 7, showing a ninth embodiment of the present invention.

FIG. 13 is a partial plan view showing a tenth embodiment of the present invention.

FIG. 14 is a diagram corresponding to FIG. 13 showing an example different from the tenth embodiment of the present invention.

FIG. 15 is an overall longitudinal sectional view showing a conventional example.

FIG. 16 is a diagram corresponding to FIG. 2;

[Explanation of symbols]

11 is a magnet member, 11a is a magnetic pole portion, 12 is a yoke member, 12a is an outer portion of the yoke member, 12b is an inner portion of the yoke member, 12c is a lower portion of the yoke member, 12c
d is an upper portion of the yoke member, 12e is a protruding portion of the yoke member, 21 is a magnet member, 21a is a magnetic pole portion, 31 is a magnet member, 31a is a magnetic pole portion, 32 is a yoke member,
33 is a frame member, 41 is a frame member, 51 is a yoke component, 61 is a missing portion (resin passage), 71 is a gate for forming a magnet member, and 72 is a gate for forming a yoke member.

Claims (11)

[Claims] 1. A magnetic resin having magnetic anisotropy is used to form a large number of magnetic pole portions whose central portion on the stator side is the most convex.
A magnet member formed so as to be connected to an integral ring, and a yoke member integrated with the magnet member by inserting the magnet member and forming the magnet member with a soft magnetic resin. A rotor for an electric motor, characterized in that: 2. A plurality of magnetic pole portions having a shape in which a central portion on the stator side is most protruded by a magnetic resin having magnetic anisotropy,
A magnet member molded so as to be connected to an integral arc, and in a state where a plurality of the magnet members are arranged in one ring shape, the magnet member is inserted and molded by a soft magnetic resin, A rotor for an electric motor, comprising: a yoke member integrated with the magnet member. 3. A plurality of magnetic pole portions having a shape in which the central portion on the stator side is most convex due to the magnetic resin having magnetic anisotropy,
A magnet member formed so as to be integrated into an integral arc shape, and a yoke member integrated with the magnet member by inserting the magnet member and forming the magnet member with a soft magnetic resin. A rotor for an electric motor, wherein a plurality of integrated members of a member and a yoke member are integrated in a state of being arranged in a single ring shape. 4. In addition to the magnet member and the yoke member,
The rotor for an electric motor according to any one of claims 1 to 3, further comprising a frame member integrated with the molded member by inserting the molded member with a resin. 5. The rotor for an electric motor according to claim 1, wherein a yoke component made of a magnetically permeable metal is disposed on a side of the magnet member opposite to the stator. 6. The magnetic member, wherein the yoke member is formed in the recess at the boundary between the magnetic pole portions so that the yoke member is located on the side opposite to the stator from the most stator side portion of the magnetic pole portion. 4. The rotor of the electric motor according to any one of 1 to 3. 7. The rotor for an electric motor according to claim 4, wherein a frame member is formed on the stator side of the magnet member so as to surround the magnetic pole portion with a predetermined thickness. 8. A yoke member is formed on an upper portion, a lower portion, or both of the magnet member and an outer peripheral portion or an inner peripheral portion or both of the magnet member. A rotor for the electric motor according to any one of the above. 9. A magnetic pole part boundary portion of a magnet member,
4. A resin passage is formed.
A rotor for the electric motor according to any one of the above. 10. A system according to claim 1, wherein a part of the yoke member is projected from a frame member covering the yoke member, and the projected portion is magnetized with a greater number of magnetic poles than the magnetic pole portion of the magnet member. A rotor for an electric motor according to any of the claims. 11. The molding member of the magnet member and the yoke member, wherein the number of molding gates is equal to or half of the number of magnetic pole portions of the magnet member, and each molding gate is set near the center of the magnetic pole portion. 4. The rotor of the electric motor according to any one of 3.