JP2006014520A - Rotating electric machine outer rotor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reinforce and fix a rotor iron core sufficiently, even if it is weak in strength, and to stabilize its characteristics. <P>SOLUTION: A molding member 18 is obtained by adding glass fibers (fillers) by 20 weight percent to 40 weight percent to, for example, polyethylene terephthalate (PET) as one of thermoplastic resins available in many varieties and for which many kinds of additives are applicable unlike thermosetting resins. Then, a frame 6, a shaft supporting body 7, the rotor iron core 9, Nd magnets 14 and the like are integrated with each other by the molding member 18. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an abduction rotor for a rotating electrical machine configured by inserting a permanent magnet into a magnet insertion hole formed in a rotor core.

As the rotating electrical machine, for example, there is an outer rotation type (outer rotor type) permanent magnet type electric motor (permanent magnet type motor). This includes a stator that is formed in a substantially cylindrical shape with a coil housed in a slot, and a rotor that is positioned so as to be opposed to the periphery of the stator via a gap (gap). Then, a plurality of magnetic pole permanent magnets formed in an arc shape along the inner peripheral surface are fixed to the inner peripheral surface of the rotor by, for example, adhesion, thereby forming a magnetic pole with respect to the stator. It is supposed to be. In such a rotor, as a permanent magnet for a magnetic pole, generally, a ferrite magnet having a high degree of freedom in shaping (shape) and strength is widely used (for example, see Patent Document 1).
JP-A-8-182282

  By the way, in recent years, as the efficiency of various devices has been promoted in a wide range of fields including home appliances, the efficiency of rotating electrical machines has been demanded. In order to cope with this, a rotary electric machine for a rotor using a rare earth-containing magnet having high magnetic properties, for example, an Nd magnet (neodymium magnet), has been provided as a permanent magnet for a magnetic pole. Here, the Nd magnet generally has a low degree of freedom in shaping (shape) and is fragile, so that it is usually formed in a rectangular parallelepiped. Accordingly, corresponding to this, a rotor core (laminated core) is formed with a rectangular magnet insertion hole into which the Nd magnet can be inserted, and the Nd magnet is inserted into the magnet insertion hole to serve as a rotor. It is configured.

  The rotor configured as described above has high magnetic characteristics, but has a plurality of magnet insertion holes formed in the rotor core at the time of manufacture, so that the overall strength is weakened. Therefore, in general, in order to reinforce the rotor core and to fix the rotor core and the Nd magnet, each member is made of resin (mold material) by an injection mold with the Nd magnet inserted into the magnet insertion hole. ) To be integrated. As this resin, a thermosetting resin that is usually inexpensive and excellent in fluidity is used. However, thermosetting resins have few types of additives, and there are few types of additives for improving the physical properties. For example, the properties of the resin itself (strength and fluidity) It is difficult to change the sex etc.) appropriately. Therefore, for example, for a rotor core having a large number of laminated sheets and weak strength, the thermosetting resin as described above sometimes cannot be sufficiently reinforced and fixed. As a result, the characteristics of the rotor itself may be adversely affected, and eventually the characteristics of the rotating electrical machine may be adversely affected.

  The present invention has been made in view of the above circumstances, and the object of the present invention is to make the molding material a thermoplastic resin so that the physical properties can be appropriately changed, even if the rotor core is weak in strength. An object of the present invention is to provide an abduction rotor for a rotating electrical machine that can be sufficiently reinforced and fixed to stabilize its characteristics.

  In order to achieve the above object, an outer rotor of a rotating electric machine according to the present invention is a rotor core having a shaft support and a magnet insertion hole that is provided so as to rotate with the shaft support and into which a permanent magnet is inserted. And a permanent magnet inserted into the magnet insertion hole of the rotor core, so that the permanent magnet is integrated with the rotor core by a resin molding material and the rotor core itself is integrated. In the above-described abduction type rotor, the resin is a thermoplastic resin (invention of claim 1).

  According to this configuration, it is possible to appropriately change the physical properties of the resin by appropriately adjusting the type of resin and additives to be added to the resin, so that appropriate reinforcement and fixing depending on the strength of the rotor It can be performed.

  As described above, according to the outer rotor of the rotating electric machine of the present invention, the resin core is made of thermoplastic resin and its physical properties are appropriately changed to sufficiently reinforce even the weakly strong rotor core. And it has the outstanding effect that it can fix and can stabilize the characteristic.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In a rotary electric machine, for example, an outer rotation type (outer rotor type) permanent magnet type electric motor (permanent magnet type motor), as shown in FIG. 2, a stator 1 has a stator core 3 having a large number of teeth 2 radially. And a stator resin X provided so as to cover the stator core 3 and a stator winding 4 wound around each of the teeth 2. On the other hand, the rotor 5 is positioned via the rotor 1 and the gap Y, and the details of the manufacturing method will be described later, but a magnetic frame 6 having a circular container shape, A shaft support 7 positioned in the center and fixed integrally with the frame 6, and a rotor core 8 disposed on an inner peripheral portion of an annular wall 6a provided on the opening side of the outer peripheral portion of the frame 6; have. The rotor core 8 is formed by first punching a steel plate (electromagnetic steel plate) to form a core punch plate 9 and laminating a plurality of the core punch plates 9. In FIG. 2, the resin described later is not shown for convenience of explanation.

  As shown in FIG. 3, the punched iron core punch plate 9 has a yoke portion 10 and a magnetic pole portion 11, and a rectangular magnet insertion hole 12 is provided between the yoke portion 10 and the magnetic pole portion 11. (12a, 12b) are formed. A semicircular resin introduction portion 10a is also formed in the magnetic pole insertion hole 12 (12a, 12b). Of the stacked core core punch plates 9, the first (lowermost in FIG. 3) and last (uppermost in FIG. 3) core punch plates 9a and 9b include the yoke portion 10 and A bridge portion 13 is formed so as to connect the magnetic pole portion 11. The first iron core punch 9a has a magnet insertion hole 12b that is narrower than the other magnet insertion holes 12a (see FIGS. 1 and 4; for convenience of explanation, FIG. In the bottom). The magnet insertion holes 12a and 12b are configured as rectangular magnet insertion holes 12 by laminating iron core punch plates 9.

  Then, as shown in FIG. 3, a permanent magnet, for example, an Nd magnet 14 is inserted into the magnet insertion hole 12 of the rotor core 8 from the direction of arrow A. In this case, the Nd magnet 14 is formed into a rectangular shape by sintering a magnetic powder containing a rare earth, for example, Nd (neodymium). As shown in FIG. 4, the rotor core 8 is inserted into the cavity 17 formed by the upper die 15 and the lower die 16 with the Nd magnet 14 inserted into the magnet insertion hole 12 as shown in FIG. It is accommodated via the spacer C, and the frame 6 is disposed outside thereof. Then, a polyethylene terephthalate (PET) molding material (indicated in FIG. 1) 18 is injected from the injection port 15 a of the upper mold 15. Thereby, the molding material 18 is formed between the magnet insertion hole 12 and the Nd magnet 14 (particularly, the resin introducing portion 13), between the frame 6 and the rotor core 8, or the end face 6b of the frame 6 (see FIG. 1 and FIG. 4) and the molds 15 and 16 (at this time, the shaft support 7 is fixed integrally with the frame 6), etc. Thus, the stator cores 8 or the rotor core 8 and the Nd magnet 14 are fixed to each other, and the rotor 5 is configured accordingly. 1 and 3 are reversed in the vertical direction for convenience of explanation.

  Here, the physical properties of the polyethylene terephthalate, which is the base material of the molding material 18, are preferably in the range shown in FIGS. 5 to 8, and the details will be described. First, FIG. 5 shows the relationship between the dimension (mm) of the gap Y (see FIG. 2) and the tensile strength (MPa). In order to affect the characteristics of the permanent magnet motor, the size of the gap Y is generally considered to be about 1.0 (mm) on average, and at least about 0.6 (mm) is required. ing. Therefore, the physical properties of the polyethylene terephthalate in the present embodiment are, for example, even when a tensile force of about 100 (MPa) is applied to the inner circumferential direction of the rotor 5 (including a tensile force in the inner circumferential direction by a magnetic attractive force). It is preferable that the gap Y of about 0.6 (mm) can be maintained. With polyethylene terephthalate having physical properties that cannot maintain a gap Y dimension of about 0.6 (mm) by applying a tension of about 100 (MPa), the rotor 5 cannot be sufficiently reinforced or fixed.

  FIG. 6 shows the relationship between heat shock resistance (cycle) and elongation (%). Since the elongation (%) affects the fluidity of the resin, it is generally considered that 3.0% or more is good. Therefore, the physical properties of polyethylene terephthalate in this example can maintain an elongation of about 3.0 (%), preferably 3 (%) or more, even when heat shock resistance of 200 (cycle) or more is applied. Good. If about 3.0 (%) cannot be maintained, the resin cannot reach every corner in the cavity 17 and the rotor 5 cannot be securely reinforced or fixed, and heat shrinkage with the rotor core 8 is not possible. Cracks or the like occur due to the difference.

  FIG. 7 shows the relationship between the gap Y (mm) and the bending elasticity (GPa). Also in this bending elasticity (GPa), the physical properties of the polyethylene terephthalate of this embodiment include, for example, a bending stress of about 6.0 (MGa) in the inner circumferential direction of the rotor 5 (including tension in the inner circumferential direction due to magnetic attraction force). In the case where a gap Y of about 0.6 (mm) is maintained, it is preferable that the gap Y is maintained. Polyethylene terephthalate having physical properties that cannot maintain about 0.6 (mm) cannot be sufficiently reinforced or fixed to the rotor 5. FIG. 8 shows the relationship between the gap Y (mm) and the impact strength (J / m). Also in this impact strength (J / m), the polyethylene terephthalate of the present example is 0.6 (in the case where an impact stress of about 120 (J / m) is applied to the inner circumferential direction of the rotor 5, for example. It is preferable to maintain a gap Y of about mm). Polyethylene terephthalate having physical properties that cannot maintain about 0.6 (mm) cannot be sufficiently reinforced or fixed to the rotor 5.

  Here, the molding material 18 is configured by adding, for example, glass fiber (a filler) as an additive in the polyethylene terephthalate having physical properties as shown in FIGS. The addition amount (glass fiber ratio) of the glass fiber with respect to the molding material 18 at this time is demonstrated with reference to FIG. FIG. 9 is a diagram showing the relationship between the gap Y (mm) and the glass fiber ratio (% by weight) when a magnetic attractive force in the inner circumferential direction by the Nd magnet 14 is applied to the rotor 5. As is apparent from FIG. 9, when glass fibers of about 20 (gravity%) to 40 (weight%) are added, a gap Y of about 0.6 (mm) is obtained even when the magnetic attractive force of the Nd magnet 14 is applied. The molding material 18 that can be maintained and has sufficient strength can be obtained. When the glass fiber ratio is less than 20 (% by weight), the change of the characteristics is not so much seen. On the contrary, when the glass fiber ratio is more than 40 (% by weight), an appropriate fluidity cannot be obtained. May occur, and the entire rotor 5 may be lowered in strength.

The rotor core 8 and the Nd magnet 14 are integrated with each other in the cavity 17 by the molding material 18 configured as described above.
According to the outer rotating rotor 5 of the rotating electric machine having such a configuration, first, the resin is a polyethylene terephthalate which is a thermoplastic resin, and the physical properties of the resin are tensile strength of 100 MPa or more, elongation of 3.0% or more, bending Elasticity was set to 6.0 GPAa or more, impact strength was set to 120 J / m or more, and 20 wt% to 40 wt% glass fiber was added to the resin to obtain a molding material 18. For this reason, it can be set as the molding material 18 which has sufficient intensity | strength. Thereby, the rotor core 8 is a lamination | stacking iron core, and since the magnet insertion hole 12 grade | etc., Is formed in the rotor core 8, it is weak in intensity | strength. Even if it is a case, since the reinforcement | strengthening and each member can be fixed enough, the characteristic of the abduction type | mold rotor 5 can be stabilized.

Further, since the fluidity of the thermoplastic resin can be appropriately adjusted depending on the kind of polyethylene terephthalate or the like, or the kind and amount of the additive, it is possible to reduce burrs generated at the joint of the mold. Further, the thermoplastic resin can shorten the curing time as compared with the thermosetting resin.
The rotor 5 may be configured without the frame 6.

  The thermoplastic resin may have any physical properties as shown in FIGS. 5 to 8 such as polybutylene terephthalate, and the additive is not limited to the glass fiber filler, and the strength of the base material is moderate. Anything that can be improved.

1 is an exploded perspective view showing a part of a rotating electrical machine, showing an embodiment of the present invention. Broken perspective view of rotating electrical machine Cross-sectional perspective view showing a method of inserting a permanent magnet for a magnetic pole and a part of the state where the core core punching plates are laminated Cross section of the rotor located in the mold This diagram explains the physical properties of the resin and shows the relationship between the gap length and the tensile strength. Fig. 5 equivalent diagram showing the relationship between heat shock resistance and elongation FIG. 5 equivalent diagram showing the relationship between the gap and the bending elasticity FIG. 5 equivalent diagram showing the relationship between gap and impact strength FIG. 5 equivalent diagram showing the relationship between the gap and the glass fiber ratio when a magnetic attractive force is applied by an Nd magnet

Explanation of symbols

In the drawings, 5 is a rotor (external rotation type rotor), 7 is a shaft support, 8 is a rotor core, 12 is a magnet insertion hole, 14 is an Nd magnet (permanent magnet), and 18 is a molding material.

Claims (4)

A rotor core having a shaft support, a magnet insertion hole provided so as to rotate together with the shaft support, and a permanent magnet inserted therein; and a permanent magnet inserted into the magnet insertion hole of the rotor core,
In an abduction type rotor in which a permanent magnet is integrated with the rotor core by a resin molding material and the rotor core itself is integrated,
An abduction type rotor for a rotating electrical machine, wherein the resin is a thermoplastic resin.   2. An abduction rotor for a rotating electrical machine according to claim 1, wherein the magnetic pole permanent magnet is formed by sintering magnetic powder containing a rare earth.   The resin has physical properties of a tensile strength of 100 MPa or more, an elongation of 3.0% or more, a flexural elasticity of 6.0 GPa or more, and an impact strength of 120 J / m or more. The outer rotor of a rotating electrical machine according to claim 1 or 2, wherein The abduction type rotor for a rotating electrical machine according to any one of claims 1 to 3, wherein the resin is polybutylene terephthalate or polyethylene terephthalate.

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