JP2009240109A - Electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric motor which is equipped with a rotor core, where a permanent magnet can be easily positioned in a magnet insertion hole and whose parts count is small and whose structure is simplified. <P>SOLUTION: The electric motor 1 has: a rotor shaft 3, a rotor core 5, which consists of a laminate of thin silicon steel plates being made, by laminating a plurality of thin silicon steel plates 5a, 5b and 5c and is outserted to the rotor shaft 3; a plurality of magnet insertion holes 7, which is formed in parallel with the axis of the rotor shaft 3 in this rotor core 5; and a plurality of permanent magnets 8, which are mounted severally in these magnet insertion holes 7. The thin silicon steel plate 5b on one end of the rotor core 5 is equipped with a sealing section 10, which blocks each magnet insertion hole 7 capable of receiving the permanent magnet 8, and a small hole 10a, which leaks a part of an adhesive for bonding the permanent magnet 8, is formed in this sealing section 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electric motor including a rotor core made of a thin laminate of silicon steel, a plurality of magnet insertion holes formed in the rotor core, and a plurality of permanent magnets respectively mounted in the magnet insertion holes. In particular, the present invention relates to a rotor iron core provided with a sealing portion that closes each magnet insertion hole so that a permanent magnet can be received at one end of the rotor core.

  Conventionally, various electric motors having a rotor and a stator have been put to practical use. The rotor includes a rotor shaft, a rotor iron core that is formed of a silicon steel thin plate laminate in which a plurality of silicon steel thin plates are laminated, and is fitted and fixed to the rotor shaft, and a plurality of permanent magnets attached to the rotor iron core. The stator has a stator winding and a stator iron core, and is disposed outside the rotor.

  The plurality of permanent magnets were attached to the outer periphery of the rotor with an adhesive or the like. In this case, however, there is a possibility that the permanent magnets may be peeled off from the rotor iron core due to centrifugal force during motor rotation. It was. In the rotor shown in FIG. 9, a plurality of magnet insertion holes 32 parallel to the axis of the rotor shaft 31 are formed in the rotor iron core 30, and a plurality of permanent magnets 34 are mounted in the magnet insertion holes 32, respectively. The magnet 34 is bonded to the rotor core 30 with an adhesive.

In the rotor shown in FIG. 10, a plurality of magnet insertion holes 42 parallel to the axis of the rotor shaft 41 are formed in the rotor iron core 40, and a plurality of permanent magnets 44 are mounted in the magnet insertion holes 42, respectively. Metal thin plates 45a and 45b are provided at both ends of the rotor core 40, and the axial positions of the plurality of permanent magnets 44 are restricted.
In the rotor shown in FIG. 11, a plurality of magnet insertion holes 52 parallel to the axis of the rotor shaft 51 are formed in the rotor iron core 50, and a plurality of permanent magnets 54 are mounted in the magnet insertion holes 52, respectively. A thin metal plate 55 is provided only at one end of the rotor core 50, the axial position of the permanent magnet 54 is regulated, and the permanent magnet 54 is bonded to the insertion hole 52 with an adhesive.

On the other hand, the rotor core 30 of the permanent magnet type rotor of Patent Document 1 includes a first stack group 30A having a plurality of magnet insertion holes 32 and a second stack group 30B having a plurality of magnet insertion holes 32. . By shifting the first stacked group 30A by a few millimeters in the circumferential direction with respect to the second stacked group 30B, the permanent magnet 60 mounted in the magnet insertion hole 32 and the inner wall of the magnet insertion hole 32A of the first stacked group are aligned with the second stacked layer. It is sandwiched between the inner walls of the group magnet insertion holes 32B. The outer peripheral side surface 63 of the permanent magnet 60 is fixed in close contact with the outer peripheral side inner walls 35 of the magnet insertion holes 32A and 32B.
JP 2007-49803 A

  However, in the rotor of FIG. 9, the permanent magnet 34 may move in the axial direction in the magnet insertion hole 32. In the rotor of FIG. 10, the metal thin plates 45 a and 45 b are required separately from the rotor core 40, which increases the manufacturing cost and creates a small gap between the inner surface of the magnet insertion hole 42 and the permanent magnet 44. There is a problem that abnormal noise is generated during acceleration / deceleration of the motor.

  As in the rotor of FIG. 10, the rotor of FIG. 11 requires a metal thin plate 55 different from the rotor core 50, and the manufacturing cost is high, and the tip of the permanent magnet 55 and the metal thin plate 55 are inserted when the magnet is inserted. There is a problem that the permanent magnet 55 cannot be accurately positioned because there is no escape space for the adhesive accumulated between the two.

  In the rotor of Patent Document 1, since the permanent magnets have gaps in the magnet insertion holes 32 of the first and second stacked groups, the permanent magnets are positioned in the axis of the rotor in the magnet insertion holes during long-term use. On the other hand, there is a possibility of wobbling in an inclined manner. In addition, the magnetic path is reduced due to the gap, and the magnetic resistance is increased. Since there is no means for joining the first stack group and the second stack group, it is necessary to fix the first and second stack groups by bonding or the like, which is troublesome.

  In order to externally fix and fix the rotor iron core of Patent Document 1 to the rotor shaft, as shown in FIG. Is expensive to manufacture, like the rotor shown in FIG. As shown in FIG. 9 of Patent Document 1, the end plate can be omitted by closing both ends of the magnet insertion hole with about three silicon steel thin plates. However, when the rotor core is fixed to the rotor shaft after the permanent magnet is placed in the magnet insertion hole of the rotor core, if the rotor core is heated to about 400 to 500 ° C. and shrink-fitted, the characteristics of the permanent magnet will be increased. Since it deteriorates, it becomes necessary to fix the rotor core to the rotor shaft by means other than shrink fitting.

  An object of the present invention is to provide an electric motor including a rotor core having a simple structure capable of easily and reliably positioning a plurality of permanent magnets in the axial direction and suppressing the number of parts.

  The electric motor according to claim 1 comprises a rotor shaft, a rotor iron core comprising a silicon steel thin plate laminate in which a plurality of silicon steel thin plates are laminated, and being fitted and fixed to the rotor shaft, and a shaft of the rotor shaft on the rotor iron core. In the electric motor having a plurality of magnet insertion holes formed in parallel with the core and a plurality of permanent magnets respectively attached to the plurality of magnet insertion holes, the silicon steel thin plate at one end of the rotor core is the permanent magnet It is characterized by having a blocking portion that closes each magnet insertion hole so that it can be received.

  In an electric motor having a plurality of magnet insertion holes formed in the rotor iron core and a plurality of permanent magnets respectively attached to the plurality of magnet insertion holes, when inserting the plurality of permanent magnets into each magnet insertion hole In addition, the end portions of the permanent magnets are received by the blocking portions, and are positioned in the axial direction.

  The electric motor according to claim 2 is characterized in that, in the invention according to claim 1, the permanent magnet mounted in the magnet insertion hole is bonded to the rotor core by an adhesive.

  According to a third aspect of the present invention, there is provided the electric motor according to the second aspect, wherein a small hole communicating with the magnet insertion hole is formed in each of the blocking portions, and the permanent magnet is inserted from the small hole when the permanent magnet is inserted into the magnet insertion hole. It is characterized by leaking a part of the adhesive.

  According to the first aspect of the present invention, the rotor shaft, the rotor core fitted and fixed to the rotor shaft, the plurality of magnet insertion holes formed in the rotor core, and the plurality of magnet insertion holes are respectively mounted. Further, in the electric motor having a plurality of permanent magnets, the silicon steel thin plate at one end of the rotor iron core has a blocking portion that closes each magnet insertion hole so that the permanent magnet can be received. It can be surely positioned in the axial direction by simply inserting the tip of each permanent magnet into contact with each blocking portion. Since the silicon steel thin plate at one end of the rotor core is provided with a blocking portion that closes each magnet insertion hole, the number of components can be reduced without requiring separate parts for positioning, and the cost can be reduced. I can do it.

  According to the invention of claim 2, since the permanent magnet mounted in the magnet insertion hole is bonded to the rotor iron core by an adhesive, each permanent magnet is fixed to the insertion hole, and abnormal noise during acceleration / deceleration is obtained. Can be prevented.

  According to the invention of claim 3, a small hole communicating with the magnet insertion hole is formed in each of the blocking portions, and when the permanent magnet is inserted into the magnet insertion hole, a part of the adhesive is passed through the small hole. Since it leaks, when each permanent magnet is inserted into the magnet insertion hole, the adhesive will not accumulate but will be discharged from the small hole to the outside, so each permanent magnet should be fixed in contact with the sealed part. Can do.

  Hereinafter, the best mode for carrying out an electric motor according to the present invention will be described based on examples.

  As shown in FIGS. 1 to 7, the electric motor 1 includes a rotor 2, a stator 20, a case 30, and the like. The rotor 2 includes a rotor shaft 3, a rotor iron core 5, a plurality of magnet insertion holes 7, and a plurality of permanent magnets 8. The stator 20 includes a stator core 21 having a plurality of pole forming portions 21a, a plurality of stator windings 22, and insulating covers 23 and 24 made of synthetic resin. A cooling fan 25 is provided on the rotor shaft 3 in the case 30.

  In the electric motor 1, a rotating magnetic field is generated in the stator core 21 when an alternating current is passed from the drive circuit to the stator winding 22. A rotational torque for rotating the rotor 2 is generated by the rotating magnetic field, and the rotor 2 is rotationally driven at the same cycle as the alternating current. In the following description, the left side of FIG. 1 is the left side and the right side is the right side.

  As shown in FIGS. 1 and 2, the rotor shaft 3 has a core mounting portion 3 a having a diameter slightly larger than both ends of the rotor shaft 3 at the center and substantially the same diameter as the through hole 6 of the rotor core 5. . When the rotor core 5 is mounted on the rotor shaft 3, the rotor core 5 is heated to a high temperature (for example, about 400 to 500 ° C.), and the rotor core 5 is thermally expanded. Then, shrink fitting is performed to return the rotor core 5 to room temperature and fix it. For this reason, the rotor core 5 can be mounted on the rotor shaft 3 without requiring other components.

Next, the rotor core 5 will be described.
As shown in FIGS. 1 to 5, the rotor iron core 5 is formed from a silicon steel thin plate laminate in which a plurality of silicon steel thin plates 5 a, 5 b, 5 c are laminated, and is externally fixed to the rotor shaft 3. A through hole 6 into which the core mounting portion 3 a of the rotor shaft 3 is inserted is provided at the center of the rotor core 5. On the outer peripheral portion of the rotor core 5, four part-cylindrical pole forming portions 9a and four groove portions 9b between the pole forming portions 9a are formed at equal intervals in the circumferential direction. In the four pole forming portions 9a, four magnet insertion holes 7 parallel to the axis of the rotor shaft 3 are formed at equal intervals in the circumferential direction at positions corresponding to the four sides of the square.

  The cross-sectional shape of the magnet insertion hole 7 is a flat rectangular shape, and the magnet insertion hole 7 is formed so that a permanent magnet 8 can be inserted. That is, the width of the magnet insertion hole 7 is slightly larger than the width of the permanent magnet 8, and the radial width of the magnet insertion hole 7 is slightly larger than the radial thickness of the permanent magnet 8. As will be described later, the right end of these magnet insertion holes 7 is closed by a blocking portion 10 of the silicon steel plate 5b at the right end of the rotor core 5. In each pole forming portion 9a, the connecting wall portion 9c in the longitudinal direction of the magnet insertion hole 7 is formed narrow.

  The permanent magnet 8 is a permanent magnet 8 formed of a rectangular parallelepiped ferrite magnet or neodymium magnet. The four permanent magnets 8 are respectively inserted into the four magnet insertion holes 7 and are positioned in the axial direction by the tips 8a coming into contact with the blocking portions 10 of the silicon steel thin plate 5b (see FIG. 7). The permanent magnet 8 is bonded to the inner surface of the magnet insertion hole 7 with an adhesive.

Next, a silicon steel sheet laminate that forms the rotor core 5 will be described.
As shown in FIGS. 3 to 7, the silicon steel sheet laminate includes a plurality of silicon steel sheets 5 a at the left end, a silicon steel sheet 5 b at the right end, and silicon steel sheets 5 a and 5 b at the left and right ends. It is formed from a silicon steel thin plate 5c.

  As shown in FIGS. 3 and 4, the silicon steel thin plate 5 a has one through hole 6, four magnet insertion holes 7, and a small circular engagement convex portion 11 of the silicon steel thin plate 5 c adjacent to the right side. An engagement hole 13 to be fitted is provided (see FIG. 5). Four engaging holes 13 positioned at the inner peripheral side of the groove 9b and four engaging holes 13 positioned at the outer peripheral side of the magnet insertion hole 7 in the pole forming portion 9a are formed. . When the silicon steel thin plates 5a, 5c, 5b of the rotor iron core 5 are pressed and laminated, the eight engaging projections 11 of the silicon steel thin plate 5c adjacent to the engagement holes 13 are fitted, respectively. The thin plate 5a and the adjacent silicon steel thin plate 5c are integrated.

  As shown in FIG. 5, the plurality of silicon steel thin plates 5c are all formed in the same structure. The silicon steel thin plate 5c has a through hole 6, four magnet insertion holes 7, eight circular engaging convex portions 11, and eight engaging convex portions 11 of the silicon steel thin plate 5c adjacent to the right side. Eight engaging recesses 11a are formed for mating. The engaging recess 11a is formed on the opposite surface of the engaging protrusion 11 with the same diameter when the engaging protrusion 11 is formed.

  As shown in FIG. 6, the silicon steel thin plate 5 b includes a through-hole 6, eight circular engagement convex portions 11, four blocking portions 10 that block the right ends of the four magnet insertion holes 7, and four sealing blocks. Four small holes 10 a formed at the center of the portion 10 are provided. The silicon steel thin plates 5a, 5b, and 5c are manufactured through a plurality of punching processes while being fed forward by a progressive press. The four blocking portions 10 are formed by omitting the punching process for forming the magnet insertion holes 7.

  As shown in FIG. 8, the blocking part 10 closes the right end of the magnet insertion hole 7 so that the right end of the permanent magnet 8 inserted in the magnet insertion hole 7 can be received. The small hole 10a is for leaking a part of the extra adhesive when the permanent magnet 8 is inserted into the magnet insertion hole 7.

Next, the operation and effect of the rotor 2 of the electric motor will be described.
When assembling the rotor core 5 of the electric motor 1, when a plurality of silicon steel thin plates 5 a, 5 b, 5 c are pressed and stacked, the eight engagement holes 13 of the silicon steel thin plate 5 a have 8 of the silicon steel thin plate 5 c. By fitting the two engaging projections 11, the silicon steel thin plates 5a and 5c are integrally coupled. Moreover, the silicon steel thin plates 5c are integrally coupled by fitting the eight engaging convex portions 11 of the silicon steel thin plate 5c adjacent to the eight engaging concave portions 11a of the silicon steel thin plate 5c. Further, the silicon steel thin plates 5c and 5b are integrally coupled by fitting the eight engagement convex portions 11 of the silicon steel thin plate 5b adjacent to the eight engagement concave portions 11a of the silicon steel thin plate 5c.

Next, the rotor core 5 is shrink-fitted and fixed to the iron core mounting portion 3 a of the rotor shaft 3.
Next, an adhesive is injected into the four magnet insertion holes 7 of the rotor core 5, and the permanent magnets 8 are inserted into the respective magnet insertion holes 7. The end portions 8a of the permanent magnets 8 are brought into contact with the blocking portions 10, and the permanent magnets 8 are accurately positioned in the axial direction. At this time, since a part of the adhesive leaks from the small hole 10 a of the blocking portion 10, excess adhesive is not accumulated in the magnet insertion hole 7 and is discharged to the outside, and each permanent magnet 8 is separated from the blocking portion 10. Can be surely prevented.

  The silicon steel thin plate 5b at one end (right end) of the rotor core 5 is provided with a blocking portion 10 that closes the right end of each magnet insertion hole 7. Positioning can be ensured by simply inserting the permanent magnet 8 into the magnet insertion hole 7 and bringing the tip 8 a of the permanent magnet 8 into contact with the blocking portion 10. In order to position the permanent magnet 8, no separate parts other than the silicon steel thin plate 5b are required, the number of parts does not increase, and the manufacturing cost can be reduced.

  Since the permanent magnet 8 mounted in the magnet insertion hole 7 is bonded to the rotor iron core 5 with an adhesive, the permanent magnet 8 can be fixed to the magnet insertion hole 7 respectively, and an abnormal noise such as rattling occurs during acceleration / deceleration. Can be prevented. Since the silicon steel thin plates 5a, 5b, and 5c can be firmly coupled through the plurality of engagement holes 13, the plurality of engagement projections 11, and the plurality of engagement recesses 11a, they can be coupled at low cost. .

  In the silicon steel thin plates 5a, 5b and 5c, the engagement hole 13, the engagement convex portion 11, and the engagement concave portion 11a are also provided on the outer peripheral side of the magnet insertion hole 7 so as to be coupled. Even if the width is reduced and the pole forming portion 9a is easily distorted, the pole forming portions 9a can be stacked in close contact, and the width of the magnet insertion hole 7 is increased as much as possible to improve the performance of the electric motor 1. be able to.

Next, a modified example in which the above embodiment is partially modified will be described.
1] The number of the magnet insertion holes 7 and the permanent magnets 8 is not necessarily four, and can be appropriately changed according to the specification, and the number of the blocking portions 10 is also changed accordingly.
2] The blocking portion 10 is not necessarily provided on the silicon steel thin plate 5b on the right end surface, and may be provided on the silicon steel thin plate 5a on the left end surface.

It is sectional drawing of the electric motor of Example 1 of this invention. It is sectional drawing of a rotor. It is a perspective view of a rotor. It is a figure which shows the silicon steel thin plate 5a. It is a figure which shows the silicon steel thin plate 5c. It is a figure which shows the silicon steel thin plate 5b. It is a principal part enlarged view of the periphery of the engagement convex part and engagement concave part of a rotor iron core. It is a principal part enlarged view of the periphery of the right end part of the magnet insertion hole of a rotor iron core. It is principal part sectional drawing of the rotor of the conventional electric motor. It is principal part sectional drawing of the rotor of another conventional electric motor. It is principal part sectional drawing of the rotor of another conventional electric motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor 2 Rotor 3 Rotor shaft 5 Rotor core 6 Through hole 7 Magnet insertion hole 8 Permanent magnet 10 Sealing part 10a Small hole 11 Engaging convex part

Claims (3)

A rotor core, a rotor core made of a silicon steel sheet laminate obtained by laminating a plurality of silicon steel sheets, and a plurality of rotor cores fitted and fixed to the rotor shaft, and a plurality of rotor cores formed in parallel to the axis of the rotor shaft In an electric motor having a plurality of permanent magnets respectively mounted in the plurality of magnet insertion holes,
An electric motor, wherein a silicon steel thin plate at one end of the rotor iron core includes a blocking portion that closes each magnet insertion hole so as to receive the permanent magnet.   The electric motor according to claim 1, wherein the permanent magnet mounted in the magnet insertion hole is bonded to the rotor core with an adhesive.   A small hole communicating with the magnet insertion hole is formed in each sealing portion, and a part of the adhesive is leaked from the small hole when the permanent magnet is inserted into the magnet insertion hole. 2. The electric motor according to 2.

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