KR100889892B1 - Outer-side-rotation rotor for dynamo-electric machines - Google Patents

Abstract

The present invention includes a rotor iron core (8) having a magnet insertion hole (12), a permanent magnet (14) inserted into the magnet insertion hole (12), and a rotor iron core (10) by a resin mold material (18). In the external type rotor of the rotary electric apparatus which integrates the permanent magnet 14 with respect to 8), and the rotor iron core 8 itself, it is characterized by making resin into thermoplastic resin.

Description

External rotor of rotating electric device {OUTER-SIDE-ROTATION ROTOR FOR DYNAMO-ELECTRIC MACHINES}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external rotor of a rotating electric device configured by inserting a permanent magnet into a magnet insertion hole formed in a rotor iron core.

Rotating electric devices, for example, a permanent magnet electric motor (permanent magnet type motor) of the outer rotor type, as described in Japanese Patent Application Laid-Open No. 182282, have a stator formed in a substantially cylindrical shape with a coil housed in a slot. And a rotor positioned facing the gap around the stator. On the inner circumferential surface of the rotor, a plurality of permanent magnets for magnetic poles formed in an arc shape along the inner circumferential surface are fixed, for example, by bonding. As a result, magnetic poles are formed in the rotor. Ferrite magnets having a high degree of freedom in shape (shape) and high strength have been widely used for magnetic pole magnets.

However, in various fields, including the home appliance field, there is a demand for high efficiency of devices, and accordingly, there is a need for high efficiency of rotary electric devices used in these devices. For this reason, there has been provided a rotary electric device using a rare earth-containing magnet having good magnetic properties, for example, an Nd magnet (neodymium magnet), as a permanent magnet for magnetic poles. Nd magnets are generally formed in a rectangular parallelepiped because of their low degree of freedom in shape (shape) and weakness. The rotor is formed by forming a rectangular magnet insertion hole for inserting the Nd magnet into the rotor iron core (laminated iron core) and inserting the Nd magnet into the magnet insertion hole.

As described above, the rotor has a higher magnetic property, but since a plurality of magnet insertion holes are formed in the rotor core, the overall strength is lowered. Therefore, in order to reinforce the rotor iron core and fix the rotor iron core and the Nd magnet, each member is integrated with a resin (molding material) in the state where the Nd magnet is inserted into the magnet insertion hole.

Currently, thermosetting resins which are inexpensive and have excellent fluidity are used as the resins. However, thermosetting resins have a narrow setting range of molding conditions, such as a small number of the thermosetting resins and a small number of additives used for improving physical properties. For this reason, it is difficult to change the physical property (for example, strength or fluidity) of resin. Therefore, for example, even if a thermosetting resin is used for a rotor core having a large number of laminated sheets and low strength, sufficient reinforcement and fixing may not be possible. As a result, there is a concern that the rotor, and furthermore, adversely affects the characteristics of the rotating electric apparatus.

It is an object of the present invention to provide an external rotor of a rotating electric apparatus that can sufficiently reinforce and fix the rotor iron core and a magnet even with a low strength rotor iron core.

(Means to solve the task)

The present invention includes a rotor iron core having a magnet insertion hole, a permanent magnet inserted into the magnet insertion hole, and integrates the permanent magnet with respect to the rotor iron core by a mold material of resin, and the rotor iron core itself. In the external rotor of the rotary electric machine to integrate the resin, the resin is a thermoplastic resin, 20% to 40% by weight of glass fiber is added to the resin, the physical properties of the resin to which the glass fiber is added It is characterized by being 100 MPa or more of tensile strength, 3.0% or more of elongation, 6.0 GPa or more of bending elastic strength, and 120 J / m or more of impact strength.

(Effects of the Invention)

Since the outer rotor of the rotary electric machine of the present invention can change the physical properties of the resin as a thermoplastic resin, even a low-strength rotor iron core can sufficiently reinforce and fix the rotor iron core and the permanent magnet, and its size characteristics. Furthermore, the electrical properties can be stabilized.

1 is an exploded perspective view showing an embodiment of the present invention to enlarge a portion of the rotor,

2 is a broken perspective view of the electric motor,

3 is a perspective view illustrating a state in which a perforated plate is laminated and a method of inserting a magnet;

4 is a cross-sectional view of the rotor located within the frame;

5 is a diagram showing a relationship between the tensile strength of a resin and a gap that can be maintained when a resin having each tensile strength is used;

6 is a diagram showing a relationship between an elongation of a resin and heat shock resistance;

FIG. 7 is a diagram showing the relationship between the bending elastic strength of a resin and the gap that can be maintained when a resin having each bending elastic strength is used;

8 is a diagram showing a relationship between the impact strength of a resin and a gap that can be maintained when a resin having each impact strength is used;

9 is a diagram showing the relationship between the glass fiber ratio and the gap in the case where a magnetic attraction force by the Nd magnet is applied.

* Explanation of symbols for the main parts of the drawings

5: rotor (abduction rotor) 8: rotor iron core

12: magnet insertion hole 14: Nd magnet (permanent magnet)

18: Mold material

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment which applied this invention to the abduction type permanent magnet type electric motor (rotary electric apparatus) is demonstrated, referring drawings.

2 is a perspective view showing a part of the electric motor broken. In FIG. 2, the stator 1 is wound around a stator iron core 3 having a plurality of teeth 2 radially, a stator resin X installed to cover the stator iron core 3, and wound around each tooth 2. It consists of a stator winding 4.

The abduction rotor 5 has a magnetic frame 6 that forms a circular container shape with an open top surface. The shaft support 7 is fixed to the center part of the frame 6. The annular wall 6a is provided in the opening side of the outer peripheral part of the frame 6, and the rotor iron core 8 is arrange | positioned along the inner periphery of the annular wall 6a. The rotor iron core 8 is constituted by forming a punching plate 9 by punching an electromagnetic steel sheet and laminating a plurality of the perforated plates 9. Details of the manufacturing method of the rotor iron core 8 will be described later. In addition, resin which is mentioned later is not shown in FIG. 2 for convenience of description.

Fig. 1 is a perspective view showing a part of the rotor broken, and Fig. 3 shows a state in which the perforated plates 9 are stacked and a method of inserting a magnet. 1 and 3 are reversed in the vertical direction for convenience of explanation. The perforated plate 9 has a circular yoke portion 10 and a magnetic pole portion 11 positioned on the inner circumferential side thereof, and a rectangular magnet insertion hole is formed between the yoke portion 10 and the magnetic pole portion 11. (12) 12a and 12b are formed. Semi-circular resin introduction portions 10a are also formed in the magnet insertion holes 12a and 12b. As the perforated plate 9 is laminated, the magnet insertion hole 12 of the rectangular parallelepiped is formed as a whole. Moreover, the magnetic pole part 11 opposes the stator iron core 3 of the said stator 1 through the gap Y.

Among the perforated plates 9 to be stacked, the bridge portions connecting the yoke portion 10 and the magnetic pole portion 11 to the perforated plates 9a and 9b of the first (lowermost end in FIG. 3) and the last (most uppermost end in FIG. 3) ( 13) is formed. The first perforated plate 9a has a magnet insertion hole 12a that is narrower than the magnet insertion hole 12b formed in the other perforated plate 9 (see FIGS. 1 and 4). For convenience of explanation, the first perforated plate 9a is located at the top of FIG. 1 and at the bottom of FIG. 4.

In the magnet insertion hole 12 of the rotor core 8, as shown in Fig. 3, a magnetic component containing a permanent magnet, for example, rare earth Nd (neodymium), is sintered and molded into a rectangular shape. The Nd magnet 14 is inserted from the arrow A direction.

4 shows a cross-sectional configuration of the rotor 5 located in the mold of an injection molding machine. The rotor iron core 8 is inserted through the spacer C in the cavity 17 formed by the upper frame 15 and the lower frame 16 with the Nd magnet 14 inserted into the magnet insertion hole 12. Stored. At this time, the outer peripheral part including the annular wall part 6a of the frame 6 is also accommodated in the cavity 17. And the mold material 18 of polyethylene terephthalate (PET) which is a thermoplastic resin is injected from the injection port 15a of the upper mold 15. As shown in FIG.

Thereby, the mold material 18 is interposed between the magnet insertion hole 12 and the Nd magnet 14 (especially between the resin introduction portion 10a, the frame 6 and the rotor iron core 8, and the frame 6). It is poured between the end surface 6b (refer FIG. 2 or FIG. 4) and the two frames 15 and 16. In this way, by molding so that the whole member may be covered, the perforated plate 9 comrades rotate the rotor core 8 with each other. And Nd magnet 14, frame 6 and rotor iron core 8, frame 6 and shaft support 7 are respectively fixed.

Here, the polyethylene terephthalate which is the base material of the mold material 18 is preferably in the range shown by broken lines and arrows in FIGS. 5 to 8, respectively, and the characteristics thereof will be described in detail below. In addition, 30 weight% of glass fiber is added to the polyethylene terephthalate shown in FIGS.

5 shows the relationship between the tensile strength MPa of the resin and the size (mm) of the gap Y that can be retained when a resin having each tensile strength is used. The size of the gap Y affects the characteristics of the permanent magnet electric motor, and it is generally said that an average of about 1.0 mm is good, and a minimum of about 0.6 mm is required. Therefore, the physical properties of the polyethylene terephthalate used in the present embodiment are about 0.6 mm even when a tensile force of about 100 MPa is assumed in the inner circumferential direction of the rotor 5 (assuming tensile force in the inner circumferential direction due to magnetic attraction force). It is good to be able to keep). In the polyethylene terephthalate in which a tensile force of about 100 MPa is applied and the size of the gap Y cannot be maintained about 0.6 mm, sufficient reinforcement or fixing cannot be performed on the rotor 5. Referring to Fig. 5, the polyethylene terephthalate used in the present embodiment needs to have a tensile strength of at least 100 MPa or more, preferably 120 MPa or more.

6 shows the relationship between the elongation (%) of the resin and the heat shock (cycle). Since elongation affects the fluidity | liquidity of resin, generally 3.0% or more is good thing. Therefore, even if the physical property of the polyethylene terephthalate in this embodiment gives a heat shock of 200 cycles or more, for example, it is good to be able to maintain elongation of 3.0% or more preferably 3.0% or more. If the elongation of about 3.0% cannot be maintained, the resin cannot spread to every corner of the cavity 17, cannot reliably reinforce or fix the rotor 5, and the heat shrinkage of the rotor iron core 8 A crack or the like occurs due to the car.

FIG. 7 shows the relationship between the bending elastic strength GPa of the resin and the size (mm) of the gap Y that can be retained when a resin having each bending elastic strength is used. Even in the above-mentioned bending elasticity, the physical property of the polyethylene terephthalate of the present embodiment is 0.6 even when a bending stress of about 6 GPa (assuming bending stress in the inner circumferential direction due to magnetic attraction force) is applied in the inner circumferential direction of the rotor 5, for example. It is good to be able to maintain the gap Y of about mm. In the polyethylene terephthalate in which the size of the gap Y cannot be maintained about 0.6 mm, sufficient reinforcement or fixing cannot be performed on the rotor 5. Referring to Fig. 7, the polyethylene terephthalate used in the present embodiment needs to have a bending elastic strength of at least 6 GPa or more, preferably 7 GPa or more.

8 shows the relationship between the impact strength (J / m) of the resin and the size (mm) of the gap Y that can be retained when a resin having each impact strength is used. Also in the impact strength, the polyethylene terephthalate of the present embodiment can maintain a gap Y of about 0.6 mm even when an impact stress of about 120 J / m is applied in the inner circumferential direction of the rotor 5, for example. In the polyethylene terephthalate in which the size of the gap Y cannot be maintained about 0.6 mm, sufficient reinforcement or fixing cannot be performed on the rotor 5. Referring to Fig. 8, the polyethylene terephthalate used in the present embodiment needs to have an impact strength of at least 120 J / m or more.

Here, the additive, for example, the pillar of glass fiber, is added to the polyethylene terephthalate which is a base material of the mold material 18 used by this embodiment. The addition amount (glass fiber ratio) of the glass fiber with respect to the mold material 18 at this time is demonstrated with reference to FIG.

9 shows the relationship between the glass fiber ratio (% by weight) and the gap Y (mm) when the magnetic attraction force in the inner circumferential direction by the Nd magnet 14 is applied to the rotor 5. When the glass fiber of about 20% by weight to 40% by weight is added to the polyethylene terephthalate, even if the magnetic attraction force of the Nd magnet 14 is applied, a gap Y of about 0.6 mm can be maintained and a mold material having sufficient strength ( 18) can be obtained. If the glass fiber ratio is less than 20% by weight, there is little improvement in physical properties. On the contrary, when more than 40 weight%, proper fluidity is not obtained, and a cavity may arise in the cavity 17, and there exists a possibility that the intensity | strength of the whole rotor 5 may fall. The rotor iron core 8 and the Nd magnet 14 are integrated in the cavity 17 by the mold material 18 to which 20 to 40 weight% of glass fiber is added.

As described above, according to the present embodiment, even when the strength of the rotor iron core 8 is reduced by forming the magnet insertion hole 12 in the stacked rotor iron core 8, the rotor is formed using the mold material 18. Since the Nd magnet 14 is integrated with the iron core 8 and the rotor iron core 8 itself is integrated, the reinforcement and fixing of each member can be performed, and the size characteristics of the rotor 5 are further increased. Furthermore, the torque characteristic, rotation speed characteristic, power consumption characteristic, efficiency, etc. of a permanent magnet electric motor can be stabilized.

The resin, which is the base material of the mold material 18, is made of polyethylene terephthalate, which is a thermoplastic resin, and by adding 20% by weight to 40% by weight of glass fiber to the resin, the physical properties of the resin are 100 MPa or more in tensile strength and elongation 3.0. It was made into% or more, bending elastic strength 6.0 GPa or more, and impact strength 120J / m or more. Thereby, the intensity | strength of the mold material 18 itself becomes high, and even if the magnetic attraction force acts, the gap Y of about 0.6 mm required at least can be maintained.

In addition, the thermoplastic resin such as polyethylene terephthalate can appropriately adjust the fluidity according to the kind, the kind, the amount of the additive, and the like, so that burrs generated in the fitting medium of the mold can be reduced. In addition, the thermoplastic resin can shorten the curing time as compared with the thermosetting resin.

In addition, this invention is not limited to said embodiment, For example, the following modifications are possible.

The rotor 5 may be configured without the frame 6.

As the thermoplastic resin, in addition to polyethylene terephthalate, for example, polybutyrene terephthalate and the like may have physical properties within the ranges shown in FIGS. 5 to 8, and the additive is not limited to the filler of the glass fiber, but the strength of the base material is increased. It is good if it can improve suitably.

As described above, the abduction type rotor of the rotary electric apparatus according to the present invention is useful for a rotary electric apparatus whose strength has decreased due to the formation of a magnet insertion hole in the rotor core.

Claims (8)

The rotor iron core 8 which has the magnet insertion hole 12, and the permanent magnet 14 inserted in the said magnet insertion hole 12 are provided, The said rotor iron core 8 is made by the resin mold material 18. As shown in FIG. In the abduction type rotor of a rotary electric device, in which the permanent magnet 14 is integrated with the rotor and the rotor iron core 8 itself is integrated, The resin is a thermoplastic resin, 20 to 40 weight% of glass fiber is added to the said resin, Physical properties of the resin to which the glass fiber is added, the outer rotor of a rotary electric machine, characterized in that the tensile strength of 100MPa or more, elongation 3.0% or more, bending elastic strength 6.0GPa or more, impact strength 120J / m or more. The method of claim 1, The permanent magnet (14) is an external rotor of a rotary electric machine, characterized in that it is formed by sintering a magnetic component containing rare earth. The method of claim 1, Wherein the resin is polybutyrene terephthalate or polyethylene terephthalate. The method of claim 2, Wherein the resin is polybutyrene terephthalate or polyethylene terephthalate. delete delete delete delete

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