JP2016063734A - motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spork-type IPM motor that simply secures a high inner diameter precision by covering an inner periphery surface of a rotor core with a resin.SOLUTION: A motor comprises: a rotation part 3; a stationary part arranged at the surrounding of a rotation part 3; a bearing mechanism; and a shaft. The rotation part 3 has a plurality of magnets; rotor core 31; and a resin part 33 covering the magnet and the rotor core 31. The rotor core 31 includes: an annular inner core part positioned at the inside of radial direction of the magnet; an outer core part; and a connection part that connects a plurality of outer core elements 541 as a part positioned between the magnets of outer core part to the inner core part in the radial direction. The resin part 33 has an upper resin part 331 and a lower resin part 332. The resin part 33 includes an annular inner periphery resin part 333 covering the inner periphery surface of rotor core, and the upper resin part 331 and the lower resin part 332 are connected to the inner periphery resin part 333. The bearing mechanism or shaft is held by the inner periphery resin part 333.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an electric motor.

Conventionally, a spoke type IPM (Interior Permanent Magnet) motor is known in which magnets having a rectangular cross section perpendicular to the central axis of the motor are arranged radially in a rotor core.
In the spoke-type motor, the long side surface is magnetized, and the same poles face each other in the magnets adjacent in the circumferential direction. Further, in a spoke type IPM motor, in order to hold a magnet in a rotor core, insert molding in which resin is provided around these may be performed.

  For example, in the rotor core 23 of the motor 1 disclosed in JP 2010-63285 A, a magnet 25 is accommodated in the slot 24. The entire magnet 25 is covered with a sealing resin 27. Thereby, the magnet 25 and the rotor core 23 are integrated. The inner periphery of the rotor core 23 is not covered with the sealing resin 27.

The rotor 32 of the motor 1 disclosed in the second embodiment of JP 2014-36457 A includes a laminated core 51, a plurality of magnets 52, and a resin portion 53. The axially opposite end surfaces of the laminated core 51 and the plurality of magnets 52 and the radially outer surfaces of the magnets 52 are covered with a resin portion 53. The laminated core 51 has an inner core portion 61, a plurality of outer core portions 62, and a plurality of connecting portions 63. The plurality of connecting portions 63 connect the inner core portion 61 and the plurality of outer core portions 62. The upper surface of the upper resin portion 531 of the resin portion 53 has a gate mark portion 91. The gate mark portion 91 is located above the outer core portion 62. The lower resin portion 532 has a plurality of second positioning holes 94 at positions overlapping the outer edge portions of the plurality of outer core portions 62 in the axial direction. The resin portion 53 does not exist on the inner peripheral surface of the inner core portion 61.
JP 2010-63285 A JP 2014-36457 A

  By the way, in the rotating part of the conventional spoke type IPM motor, the inner peripheral surface of the rotor core and the lower surface of the inner peripheral part are parts that are supported at the time of insert molding, and thus are not covered with resin. Therefore, deformation of the rotor core is easily prevented. The bearing or shaft is held directly on the inner peripheral surface of the rotor core. In this case, high accuracy is required for the inner diameter of each magnetic steel plate, and the die for punching the magnetic steel plate needs to be frequently polished, which reduces the life of the die. When the bearing is held on the upper side and the lower side of the rotor core, the motor becomes large in the axial direction.

  The main object of the present invention is to easily ensure high inner diameter accuracy by covering an inner peripheral surface of a rotor core with a resin in a spoke type IPM motor.

  A motor according to an embodiment of the present invention includes a rotating unit that rotates about a central axis that faces in the up-down direction, a stationary unit that is disposed around the rotating unit, and the rotating unit that is disposed with respect to the stationary unit. A bearing mechanism that is rotatably supported and a shaft that is rotatably supported relative to the bearing mechanism. The rotating portion includes a plurality of magnets arranged in a circumferential direction, a rotor core in which a plurality of magnetic steel plates are laminated in an axial direction, and a resin portion that covers the plurality of magnets and the rotor core. The length in the radial direction of each of the plurality of magnets is longer than the length in the circumferential direction in plan view. The rotor core includes a ring-shaped inner core portion positioned radially inward of the plurality of magnets, an outer core portion positioned radially outward of the inner core portion, and the outer core portion and the inner core portion. And a plurality of connecting portions connected in the direction. The outer core part has a plurality of outer core elements connected to the inner core part through the plurality of connecting parts. The resin part includes an upper resin part that covers at least part of the upper surface of the rotor core and at least part of the upper surface of each magnet, and a lower part that covers at least part of the lower surface of the rotor core and at least part of the lower surface of each magnet. A resin portion. The resin part further includes an annular inner resin part that covers an inner peripheral surface of the rotor core, and the upper resin part and the lower resin part are continuous with the inner resin part, and the bearing mechanism or the shaft Is held by the inner peripheral resin portion.

  According to the present invention, high inner diameter accuracy can be obtained without being affected by the inner diameter accuracy of the magnetic steel sheet.

FIG. 1 is a plan view of a motor according to one embodiment. FIG. 2 is a longitudinal sectional view of the motor. FIG. 3 is a plan view of the rotating unit. FIG. 4 is a bottom view of the rotating unit. FIG. 5 is a longitudinal sectional view of the rotating part. FIG. 6 is a longitudinal sectional view of the rotating part. FIG. 7 is a bottom view of the rotor core and the magnet. FIG. 8 is a bottom view of the rotor core. FIG. 9 is a longitudinal sectional view of the rotor core. FIG. 10 is an enlarged view of the rotor core and the magnet. FIG. 11 is a longitudinal sectional view of a rotating unit according to another example.

  In this specification, the upper side of FIG. 2 in the direction of the central axis J1 of the motor 1 is simply referred to as “upper side”, and the lower side is simply referred to as “lower side”. Note that the vertical direction does not indicate the positional relationship or direction when incorporated in an actual device. A direction parallel to the central axis J1 is referred to as an “axial direction”, a radial direction centered on the central axis J1 is simply referred to as “radial direction”, and a circumferential direction centered on the central axis J1 is simply “circumferential direction”. Call it.

  FIG. 1 is a plan view showing a motor 1 according to an exemplary embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the motor 1. Parallel diagonal lines in the details of the cross section are omitted. The motor 1 is an inner rotor type brushless motor. The motor 1 includes a stationary part 2, a rotating part 3, a bearing mechanism 4, and a circuit board 5. The bearing mechanism 4 supports the rotating part 3 so as to be rotatable with respect to the stationary part 2 around the central axis J1 of the motor 1. An impeller cup of an impeller is attached to the rotating unit 3. The motor 1 is used, for example, as a fan that cools cooling water of an automobile.

  The stationary part 2 includes a housing 21, a stator 22, and a shaft 23. The stator 22 is disposed around the rotating unit 3. The stationary part 2 is arranged around the rotating part 3. The stationary part 2 includes a housing 21, a stator 22, and a shaft 23. The housing 21 includes a base member 211 and a cover 212. The base member 211 has a substantially plate shape perpendicular to the central axis J1. The lower end of the shaft 23 is fixed to the base member 211 and protrudes upward. The shaft 23 is disposed around the central axis J1. The cover 212 is substantially cylindrical and is attached on the base member 211. An opening 521 is provided in the center of the cover 212. The rotating part 3 is exposed from the opening 521.

  Stator 22 includes a stator core 223, an insulator 221, and a coil 222. Stator core 223 includes a plurality of teeth 531 and a core back 532. The core back 532 has an annular shape centered on the central axis J1. Each tooth 531 extends radially inward from the core back 532 toward the rotating unit 3. In the stator core 223, electromagnetic steel sheets are laminated. The teeth 531 are covered with an insulator 221. A coil 222 is provided so as to surround the insulator 221.

  The circuit board 5 is attached to the lower surface of the central portion of the base member 211. The circuit board 5 controls the supply of power to the stationary unit 2. Thereby, the rotational speed of the rotation part 3 is controlled. A lid member 213 is attached to the lower part of the base member 211. The lid member 213 covers the lower surface of the circuit board 5. The base member 211 includes a protruding portion 522 that protrudes laterally. A plurality of wires 523 connected to the circuit board 5 are drawn out from the protruding portion 522.

  The bearing mechanism 4 includes two bearings 41. In the present embodiment, the bearing 41 is a ball bearing. The bearing 41 may have another structure. The two bearings 41 are provided between the shaft 23 and the rotating unit 3.

  The rotating part 3 includes a rotor core 31, a plurality of magnets 32, and a resin part 33. The magnet 32 is a permanent magnet. The rotor core 31 is disposed inside the stator 22 in the radial direction. The outer peripheral surface of the rotor core 31 is close to the inner peripheral surface of the stator 22.

  FIG. 3 is a plan view of the rotating unit 3. FIG. 4 is a bottom view of the rotating unit 3. FIG. 5 is a longitudinal sectional view of the rotating unit 3. 6 is a longitudinal sectional view of the rotating unit 3 at a position different from that in FIG. FIG. 7 is a bottom view of the rotor core 31 and the magnet 32. FIG. 8 is a bottom view of the rotor core 31. FIG. 9 is a longitudinal sectional view of the rotor core 31. In the rotor core 31, magnetic steel plates are laminated in the axial direction.

  As shown in FIG. 8, the rotor core 31 includes an outer core portion 311, an inner core portion 312, and a plurality of connecting portions 313. The inner core portion 312 is annular. The outer core portion 311 includes a plurality of outer core elements 541. The plurality of outer core elements 541 are arranged in the circumferential direction. Each outer core element 541 is substantially fan-shaped. The outer core portion 311 is located on the radially outer side of the inner core portion 312. Each connecting portion 313 connects one outer core element 541 and the inner core portion 312 in the radial direction. The connecting portion 313 extends in the radial direction and connects the circumferential center of the radially inner portion of the outer core element 541 and the outer peripheral surface of the inner core portion 312. The outer core element portion 541, the inner core portion 312 and the connecting portion 313 are a single member.

  FIG. 9 is a longitudinal sectional view of the rotor core 31 at the center in the circumferential direction of the outer core element 541. As shown in FIGS. 8 and 9, the outer core element 541 has a through hole 545 that penetrates in the axial direction. The inner peripheral portion of the rotor core 31, that is, the inner peripheral portion of the inner core portion 312 includes a core large diameter portion 551 and a core small diameter portion 552. The core large diameter portion 551 is located on the lower side in the axial direction of the core small diameter portion 552. The inner diameter of the core large diameter portion 551 is larger than the inner diameter of the core small diameter portion 552.

  As shown in FIG. 7, the magnet 32 is disposed between the outer core elements 541. Each outer core element 541 is a portion located between any of the plurality of magnets 32 in the outer core portion 311. The magnets 32 are arranged at equal intervals in the circumferential direction. The inner core portion 312 is located on the radially inner side of the plurality of magnets 32. The rotor core 31 holds a magnet 32. Each magnet 32 has a pair of long sides 611 and a pair of short sides 612 in a cross section perpendicular to the central axis J1. In other words, each radial length of the plurality of magnets is longer than the circumferential length in plan view. A center line 613 between the pair of long sides 611 passes through the center axis J1. That is, the center lines 613 of all the magnets 32 intersect on the central axis J1. The motor 1 is a spoke type IPM motor.

  The pair of long sides 611 are magnetized to different poles. In a pair of adjacent magnets 32, the same poles face each other in the circumferential direction. As a result, part of the lines of magnetic force are guided from the long sides 611 facing each other to the outside of the rotor core 31 via the outer peripheral surface of the outer core element 541, and from the outer peripheral surface of the outer core element 541 adjacent to both sides to the rotor core 31. Enter and be led to the other pole. The outer core element 541 functions as a magnetic pole part with respect to the stator 22.

  FIG. 10 is an enlarged view showing the rotor core 31 and the magnet 32. As described above, the outer core portion 311 and the inner core portion 312 are connected by the plurality of connecting portions 313. Flux barriers 546 exist between the outer core element 541 and the inner core portion 312 and on both sides in the circumferential direction of the connecting portion 313. The flux barrier 546 is a space where neither the rotor core 31 nor the magnet 32 exists. In other words, the outer core portion 311 exists on the radially outer side of the flux barrier 546. The inner core portion 312 exists on the radially inner side of the flux barrier 546. The connecting portion 313 is positioned between the pair of flux barriers 546 between the pair of adjacent magnets 32. In the present embodiment, a part of the resin portion 33 exists in the flux barrier 546. Thereby, the resin part 33 will cover the circumference | surroundings of the connection part 313, the intensity | strength of the connection part 313 can be improved and a deformation | transformation can be prevented, suppressing the wraparound of a magnetic flux.

  The resin does not necessarily exist in the flux barrier 546, and any region in the rotor core 31 that has a larger magnetic resistance than other portions may be used. For example, air or other material may be present in the flux barrier 546.

  The inner core portion 312 includes a plurality of protruding portions 547 that protrude radially outward on the outer peripheral surface. Each protrusion 547 is located between the two connecting portions 313. The short side 612 of the magnet 32 is in contact with the protruding portion 547 in the radial direction. The long side 611 of the magnet 32 is in contact with the outer core element 541 in the circumferential direction. Each flux barrier 546 is defined by the outer peripheral surface of the inner core portion 312, the connecting portion 313, the short side 612, and the protruding portion 547. The short side 612 is in contact with the two flux barriers 546.

  By providing the flux barrier 546, the magnetic flux is prevented from going radially inward, and the magnetic flux can be efficiently guided from the magnet 32 to the outer core element 541. As a result, a large amount of magnetic flux is guided to the outside in the radial direction of the outer core element 541, and the output of the motor 1 can be improved with an equivalent size. In other words, the motor 1 can be reduced in size while suppressing a decrease in output.

  In order to prevent the magnetic flux from entering the inner core portion 312, the connecting portion 313 is preferably thin. Thereby, the connection part 313 can be magnetically saturated easily, and a magnetic flux can be interrupted | blocked. Preferably, the length of the connecting portion 313 in the radial direction is longer than the width in the circumferential direction.

  FIG. 5 is a vertical cross-sectional view of the rotating portion 3 by a plane including the central axis J1 and passing through the center in the circumferential direction of the outer core element 541. FIG. 6 is a vertical cross-sectional view of the rotating unit 3 by a plane including the central axis J1 and passing through the center in the circumferential direction of the magnet 32. The plurality of magnets 32 and the rotor core 31 are covered with a resin portion 33. The resin part 33 includes an upper resin part 331, a lower resin part 332, and an inner peripheral resin part 333.

  The upper resin portion 331 covers at least part of the upper surface of the rotor core 31 and at least part of the upper surface of each magnet 32. The lower resin portion 332 covers at least a part of the lower surface of the rotor core 31 and at least a part of the lower surface of each magnet 32. Thereby, the rotor core 31 and the magnet 32 are integrated by the resin part 33 in the axial direction. Preferably, the resin portion 33 covers a part of the radially outer surface of the magnet 32, and the magnet 32 is held by the resin portion 33 in the radial direction. Of course, the holding of the magnet 32 with respect to the rotor core 31 may be realized by other structures.

  The inner peripheral resin portion 333 covers the inner peripheral surface of the rotor core 31 and has an annular shape. The boundaries between the upper resin part 331, the lower resin part 332, and the inner peripheral resin part 333 need not be determined strictly. The upper resin portion 331 and the lower resin portion 332 are continuous with the inner peripheral resin portion 333 and constitute a single member. The upper resin part 331, the lower resin part 332, and the inner peripheral resin part 333 may not be connected.

  As shown in FIGS. 3, 5, and 6, the upper resin portion 331 includes a plurality of gate marks 561, a plurality of upper core support marks 562, a plurality of upper magnet support marks 563, and a plurality of impeller mounting portions 564. And including. The gate mark 561 corresponds to the position of the gate at the time of insert molding of the resin portion 33. The circumferential position of the gate mark 561 coincides with the circumferential position of the outer core element 541. The number of gate marks 561 is the same as the number of outer core elements 541. The gate mark 561 is located on a radially inner portion of the outer core element 541.

The upper core support mark 562 is a pin mark that supports the outer core element 541 from the upper side during insert molding. The circumferential position of the upper core support mark 562 coincides with the circumferential position of the outer core element 541. The number of upper core support marks 562 is the same as the number of outer core elements 541. The upper core support mark 562 overlaps with a radially inner portion of the through hole 545 of the outer core element 541. The inside of the through hole 545 may or may not be filled with resin. In the upper core support mark 562, a part of the upper surface of the rotor core 31 is exposed.

  The upper magnet support mark 563 is a pin mark that supports the magnet 32 from above during insert molding. The circumferential position of the upper magnet support mark 563 coincides with the circumferential position of the magnet 32. The number of upper magnet support marks 563 is the same as the number of magnets 32. The radial position of the upper magnet support mark 563 is approximately the center in the radial direction of the magnet 32. In the upper magnet support mark 563, a part of the upper surface of the magnet 32 is exposed.

  The impeller attachment part 564 is a part for attaching the impeller cup to the rotating part 3. The circumferential position of the impeller mounting portion 564 coincides with the circumferential position of the outer core element 541. In the present embodiment, the number of impeller mounting portions 564 is half the number of outer core elements 541. The circumferential positions of the plurality of impeller attachment portions 564 coincide with every other circumferential position of the outer core element 541. The impeller attachment portion 564 overlaps with a radially outer portion of the outer core element 541.

  As shown in FIGS. 4, 5, and 6, the lower resin portion 332 includes a plurality of first lower core support marks 566, a plurality of second lower core support marks 567, and a plurality of lower magnet support marks. 568. The first lower core support mark 566 is a pin mark that supports at least one of the connecting portion 313 and the inner core portion 312 from the lower side during insert molding. The circumferential position of the first lower core support mark 566 coincides with the circumferential position of the outer core element 541, that is, the circumferential position of the connecting portion 313. The number of first lower core support marks 566 is half the number of outer core elements 541. The circumferential positions of the plurality of first lower core support marks 566 coincide with every other circumferential position of the outer core element 541.

  In the first lower core support mark 566, a part of the lower surface of the rotor core 31 is exposed. The mold pin corresponding to the first lower core support mark 566 may support only the inner core portion 312 or only the connecting portion 313. That is, the first lower core support mark 566 is located on the radially inner side with respect to the outer core element 541. In the present embodiment, the pins support a part of the inner core part 312 and a part of the connecting part 313. Therefore, a part of the inner core part 312 and a part of the connecting part 313 are exposed from the first lower core support mark 566.

  Resin is present around the connecting portion 313 including the flux barrier 546, but no resin is present in the first lower core support mark 566. Therefore, the presence or absence of deformation of the connecting portion 313 due to insert molding can be easily confirmed visually from the first lower core support mark 566. Thereby, before energizing the motor 1 actually, the defect resulting from the deformation | transformation of the rotor core 31 can be discovered.

  The number of the second lower core support marks 567 is the same as that of the upper core support marks 562 except for the point provided in the lower resin portion 332 and the number, the circumferential direction, and the radial position. In each second lower core support mark 567, a part of the lower surface of the rotor core 31 in the outer core portion 311 is exposed.

  The lower magnet support trace 568 is a trace of a pin that supports the magnet 32 from the lower side during insert molding. The circumferential position of the lower magnet support mark 568 coincides with the circumferential position of the magnet 32. The number of lower magnet support marks 568 is the same as the number of magnets 32. The lower magnet support mark 568 is a rectangle smaller than the magnet 32. In the lower magnet support mark 568, a part of the lower surface of the magnet 32 is exposed.

  By providing the first lower core support trace 566 radially inward of the outer core element 541, that is, by supporting the rotor core 31 radially inward of the outer core element 541 in the mold, Even if the resin is poured into the mold from the upper side to the lower side, the connection portion 313 having a small rigidity is prevented from being deformed. As a result, the quality variation of the motor 1 is reduced. Here, “preventing deformation” of the connecting portion 313 includes “reducing deformation”. The support of the rotor core 31 in the first lower core support mark 566 is particularly suitable when the radius of the rotor core 31 is larger than the axial thickness of the rotor core 31 and the connecting portion 313 is easily deformed, as shown in FIG. Yes.

  In the present embodiment, each of the plurality of first lower core support marks 566 overlaps at least a part of any of the connecting portions 313. In this case, the first lower core support trace 566 is located on the radially outer side as compared with the case where the first lower core support trace 566 overlaps only the inner core portion 312. As a result, the shape accuracy of the inner peripheral surface of the lower resin portion 332 can be improved. Improvement in the shape accuracy of the inner peripheral surface of the lower resin portion 332 is particularly preferable when the bearing 41 is held on the inner peripheral surface, as will be described later.

  The plurality of gate marks 561 are located between the plurality of first lower core support marks 566 and the plurality of second lower core support marks 567 in the radial direction. Thereby, the rotor core 31 which receives force from the flowing resin at the time of insert molding can be stably supported by the first lower core support mark 566 and the second lower core support mark 567.

  As described above, the circumferential center position of each gate mark 561 and each first lower core support mark 566 coincides with the circumferential center position of the outer core element 541. In other words, the circumferential center position of each gate mark 561 and each first lower core support mark 566 faces the radial direction through the circumferential center position of any one of the connecting portions 313 shown in FIG. It overlaps the center line 614 in the axial direction. Thereby, the rotor core 31 can be supported more stably at the time of insert molding. Of course, the support of the rotor core 31 is also stabilized when the second lower core support mark 567 is on the center line 614. However, when the plurality of second lower core support marks 567 are provided corresponding to one outer core element 541, the second lower core support marks 567 do not need to exist on the center line 614.

  As shown in FIG. 5, the resin portion 33 has a cylindrical shape centered on the central axis J <b> 1 and further includes a cylindrical resin portion 334 that protrudes upward away from the rotor core 31. The resin part 33 further includes another cylindrical resin part 335 that covers the outer periphery of the cylindrical resin part 334. Hereinafter, the cylindrical resin portion 334 is referred to as an “inner cylindrical resin portion”, and the cylindrical resin portion 335 is referred to as an “outer cylindrical resin portion”. As shown in FIGS. 3 and 6, the resin portion 33 further includes a plurality of rib portions 336 that connect the inner cylindrical resin portion 334 and the outer cylindrical resin portion 335 in the radial direction.

  As shown in FIG. 2, the inner cylindrical resin portion 334 functions as a bearing holding portion that holds the upper bearing 41 on the inner peripheral surface. The bearing 41 is accurately held by the inner cylindrical resin portion 334 in the press-fitted state. By providing the inner cylindrical resin portion 334, the bearing 41 can be held with high positional accuracy by the resin even when the rotor core 31 is thin. By providing the outer cylindrical resin portion 335 and the rib portion 336, the rigidity of the inner peripheral surface of the inner cylindrical resin portion 334 can be increased, and the holding force of the upper bearing 41 is further improved. In particular, the space between the inner cylindrical resin portion 334 and the outer cylindrical resin portion 335 where the rib portion 336 exists suppresses a decrease in the inner diameter accuracy of the inner cylindrical resin portion 334 due to resin shrinkage.

  The impeller mounting portion 564 is provided around the inner cylindrical resin portion 334 and the outer cylindrical resin portion 335. In the center of the impeller cup, a hole or a recess into which these cylindrical resin portions are inserted is provided. Thereby, it is realized to keep the height of the fan low.

  As described with reference to FIG. 9, the inner peripheral portion of the rotor core 31 includes the core large diameter portion 551 and the core small diameter portion 552. As shown in FIG. 5, the inner peripheral resin portion 333 includes a resin large diameter portion 571, a resin small diameter portion 572, and a resin step portion 573. The resin large diameter portion 571 covers the inner peripheral surface of the core large diameter portion 551. The resin small diameter part 572 covers the inner peripheral surface of the core small diameter part 552. Each of the resin large diameter portion 571 and the resin small diameter portion 572 has a substantially cylindrical shape centered on the central axis J1. The resin step portion 573 has an annular shape extending perpendicularly to the central axis J1, and connects the upper end of the resin large diameter portion 571 and the lower end of the resin small diameter portion 572 in the radial direction.

  An inner cylindrical resin portion 334 is located above the resin small diameter portion 572. The inner diameter of the resin small diameter portion 572 is smaller than the inner diameter of the inner cylindrical resin portion 334, and a step portion is formed between the resin small diameter portion 572 and the inner cylindrical resin portion 334. As shown in FIG. 2, the lower bearing 41 is held on the inner peripheral surface of the resin large diameter portion 571. The upper end of the bearing 41 is in contact with the lower surface of the resin step portion 573. Thereby, the axial position of the bearing 41 can be easily determined. The bearing 41 is accurately held by the resin large-diameter portion 571 even in a direction perpendicular to the central axis J1 in the press-fitted state. By covering the inner periphery of the rotor core 31 with the resin, it is possible to prevent the burrs of the laminated steel plates from falling off. As a result, for example, an increase in noise due to the entry of burrs into the bearing 41 and a decrease in the life of the bearing 41 are prevented.

  Further, the upper end of the lower bearing 41 is positioned above the lower surface of the rotor core 31 and the bearing 41 is held inside the rotor core 31, whereby the height of the motor 1 can be kept small and the weight can be reduced. Is also realized. When the bearing 41 is directly held by the rotor core 31, in order to maintain the inner diameter of the rotor core 31 with very high accuracy, it is necessary to increase the number of times of polishing of a die for punching a steel plate. By holding the bearing 41 with the resin portion 33, the resin molding accuracy is high in the direction perpendicular to the central axis J1, the bearing 41 can be held with high accuracy, and the resin molding temperature is low and the mold is low. Since the wear is small, it is not necessary to polish the mold in the first place, and the life of the mold can be extended.

  As shown in FIG. 2, the circuit board 5 is disposed perpendicular to the central axis J1. The lower bearing 41 is held by the inner peripheral resin portion 333, and the lower end of the shaft 23, that is, the end portion of the shaft 23 on the lower bearing 41 side is supported by the stationary portion 2. Thereby, it is possible to arrange the lower end of the shaft 23 and the circuit board 5 in the axial direction while suppressing the height of the motor 1. As a result, there is no need to provide a hole through the shaft 23 in the circuit board 5, and the circuit board 5 can be reduced in the radial direction. The motor 1 can be reduced in size, weight, and cost.

  As shown in FIGS. 1 and 2, the upper portion of the stator 22 is covered with a cover 212. The cover 212 includes a plurality of openings 214 arranged in the circumferential direction above the stator 22. The opening 214 may be a through hole, or may be cut out from the radially inner side to the outer side. The heat generated in the stator 22 is released to the outside by air flow and radiation through the opening 214. On the other hand, the cover 212 also has a function of blocking electromagnetic radiation generated from the coil end of the stator 22 and preventing EMI (electro-magnetic interference).

In order to prevent EMI, it is desirable that the opening 214 be small. However, if the opening 214 is made small, the heat dissipation performance is lowered. Therefore, in the motor 1, the center of the opening 214 is positioned between the coil 222 and the coil 222 in the circumferential direction, thereby ensuring heat dissipation while reducing EMI. Such reduction of EMI is particularly suitable for an in-vehicle motor. Further, by positioning the opening 214 between the coils 222, an air flow due to the rotation of the rotating unit 3 can be easily generated at the position of the opening 214, and heat dissipation can be ensured by the small opening 214.

  In plan view, it is desirable that the coil 222 is substantially hidden by the cover 212 and that the opening 214 is large. Therefore, it is preferable that the opening 214 has a shape in which the circumferential width gradually increases outward in the radial direction. In the example of FIG. 1, at a portion between the opening 214 and the opening 214 that are adjacent to each other, the two sides 215 in contact with both the openings 214 are oriented in the radial direction and are parallel to each other. Thereby, it is possible to easily prevent foreign matter from coming into contact with the coil 222.

  FIG. 11 is a diagram illustrating another example of the rotating unit 3 and corresponds to FIG. The diameter of the inner peripheral portion of the rotor core 31 is constant. On the other hand, the inner peripheral resin portion 333 includes a resin large diameter portion 571, a resin small diameter portion 572, and a resin step portion 573, as in FIG. The resin large diameter portion 571 covers the lower portion of the inner peripheral surface of the rotor core 31, and the resin small diameter portion 572 covers the middle portion and the upper portion of the inner peripheral surface of the rotor core 31. The inner diameter of the resin small diameter portion 572 is smaller than the inner diameter of the resin large diameter portion 571. The resin step portion 573 connects the resin large diameter portion 571 and the resin small diameter portion 572. In the resin large diameter portion 571, the lower bearing 41 is held. The upper end of the bearing 41 is in contact with the lower surface of the resin step portion 573.

  Since the inner diameter of the rotor core 31 is constant in the axial direction, the manufacturing cost of the rotor core 31 can be reduced. On the other hand, by providing the resin large-diameter portion 571, the resin small-diameter portion 572, and the resin step portion 573, the accuracy of the position of the lower bearing 41 can be ensured.

  The motor 1 can be variously changed.

  In the housing 21, the base member 211 and the cover 212 may be one member. Conversely, the housing 21 may be a combination of three or more parts. In the rotor core 31, the connecting portion 313 does not need to have a constant width. The connecting portion 313 is located radially inward of the magnet 32 and has a width equal to or smaller than the minimum width in the circumferential direction of the outer core element 541. The length of the connecting portion 313 may be short. When seen in a plan view, the connecting portion 313 is a constricted portion between the outer core element 541 and the inner core portion 312. The magnet 32 may not be rectangular when viewed from above.

  The number of poles of the rotating unit 3 and the stationary unit 2 may be variously changed. Various methods for fixing the magnet 32 to the rotor core 31 may be employed. For example, an adhesive may be used in combination, and a part of the laminated steel plate may fix the position of the magnet 32.

  The gate mark 561 and the first lower core support mark 566 may partially overlap. In this case, the connecting portion 313 receives a large force from the resin at the time of insert molding, but the first lower core support mark 566 can prevent the connecting portion 313 from being deformed.

  Each support mark formed in the resin part 33 is not limited to a hole shape. For example, it may have a notch shape that exists up to the edge of the outer periphery or inner periphery of the rotor core 31. The inner peripheral resin portion 333 does not need to cover the entire inner peripheral surface of the rotor core 31 and may cover at least a portion. The inner peripheral resin portion 333 may be continuous with only one of the upper resin portion 331 and the lower resin portion 332.

  The upper bearing 41 and the lower bearing 41 may be interchanged. That is, the inner cylindrical resin part 334 may be connected to the lower resin part 332 and the resin large diameter part 571 may be connected to the upper resin part 331. This structure is substantially the same as the structure shown in FIG. 2 in which the upper resin part 331 and the lower resin part 332 are replaced without replacing the upper bearing 41 and the lower bearing 41. As long as the gate mark 561 and the first lower core support mark 566 exist on the opposite side to the rotor core 31, the position and shape of the support mark may be variously changed.

  In the motor 1, the shaft 23 is fixed at the stationary portion 2, but a structure in which the shaft rotates may be employed. In this case, for example, the shaft is fixed in the inner peripheral resin portion. Even in this case, since the accuracy of the inner diameter of the inner peripheral resin portion can be easily increased as described above, the manufacturing cost of the rotating portion 3 can be reduced. Whether the shaft is stationary or the shaft rotates, by providing the inner peripheral resin portion, a bearing mechanism (at least a part of the bearing mechanism when the bearing mechanism includes a plurality of bearings) or It is possible to accurately hold the shaft by the inner peripheral resin portion.

  The structure in which the bearing and the shaft are held by the inner peripheral resin portion can be employed in various types of motors independently of the technique of providing a support mark radially inward of the outer core element 541. Similarly, the technique of providing the ventilation opening 214 in the cover 212 can be applied to various types of motors independently of the technique of providing a support mark radially inward of the outer core element 541. Of course, the structure in which the bearing and the shaft are held by the inner peripheral resin portion and the technique of providing the opening 212 for ventilation in the cover 212 can also be adopted in various motors independently of each other.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

  The motor according to the present invention can be used as a drive source for various applications.

DESCRIPTION OF SYMBOLS 1 Motor 2 Static part 3 Rotating part 4 Bearing mechanism 5 Circuit board 23 Shaft 31 Rotor core 32 Magnet 33 Resin part 41 Bearing (upper bearing, lower bearing)
311 Outer core part 312 Inner core part 313 Connection part 331 Upper resin part 332 Lower resin part 333 Inner circumference resin part 334 Inner cylindrical resin part (cylindrical resin part)
335 Outer cylindrical resin part (other cylindrical resin part)
336 Rib portion 541 Outer core element 551 Core large diameter portion 552 Core small diameter portion 561 Gate trace 564 Impeller attachment portion 566 First lower core support trace (first core support trace)
567 Second lower core support mark (second core support mark)
571 Resin large diameter part 572 Resin small diameter part 573 Resin step part J1 Central axis

A motor according to an embodiment of the present invention includes a rotating unit that rotates about a central axis that faces in the up-down direction, a stationary unit that is disposed around the rotating unit, and the rotating unit that is disposed with respect to the stationary unit. comprising a bearing mechanism for rotatably supporting, and a shaft that is rotating rotatably supported by a bearing mechanism. The rotating portion includes a plurality of magnets arranged in a circumferential direction, a rotor core in which a plurality of magnetic steel plates are laminated in an axial direction, and a resin portion that covers the plurality of magnets and the rotor core. The stationary part includes the shaft. The length in the radial direction of each of the plurality of magnets is longer than the length in the circumferential direction in plan view. The rotor core includes a ring-shaped inner core portion positioned radially inward of the plurality of magnets, an outer core portion positioned radially outward of the inner core portion, and the outer core portion and the inner core portion. And a plurality of connecting portions connected in the direction. The outer core part has a plurality of outer core elements connected to the inner core part through the plurality of connecting parts. The resin part includes an upper resin part that covers at least part of the upper surface of the rotor core and at least part of the upper surface of each magnet, and a lower part that covers at least part of the lower surface of the rotor core and at least part of the lower surface of each magnet. a resin portion, and the inner circumference resin portion inner peripheral surface of the annular covering at least part of the previous SL in the core portion, wherein the said upper resin portion and the lower resin portion, at least one of the inner peripheral resin section continuous with said bearing Organization is retained in the peripheral resin section.

As shown in FIG. 8, the rotor core 31 includes an outer core portion 311, an inner core portion 312, and a plurality of connecting portions 313. The inner core portion 312 is annular. The outer core portion 311 includes a plurality of outer core elements 541. The plurality of outer core elements 541 are arranged in the circumferential direction. Each outer core element 541 is substantially fan-shaped. The outer core portion 311 is located on the radially outer side of the inner core portion 312. Each connecting portion 313 connects one outer core element 541 and the inner core portion 312 in the radial direction. The connecting portion 313 extends in the radial direction and connects the circumferential center of the radially inner portion of the outer core element 541 and the outer peripheral surface of the inner core portion 312. The outer core element 541 , the inner core portion 312 and the connecting portion 313 are a continuous member.

Claims (8)

A rotating part that rotates about a central axis that faces up and down;
A stationary part arranged around the rotating part;
A bearing mechanism that rotatably supports the rotating part with respect to the stationary part;
A shaft that is rotatably supported relative to the bearing mechanism;
With
The rotating part is
A plurality of magnets arranged in a circumferential direction;
A rotor core in which a plurality of magnetic steel plates are laminated in the axial direction;
A resin portion covering the plurality of magnets and the rotor core;
With
The radial length of each of the plurality of magnets is longer than the circumferential length in plan view,
The rotor core is
An annular inner core portion located radially inside of the plurality of magnets;
An outer core portion located radially outside the inner core portion;
A plurality of connecting portions for connecting the outer core portion and the inner core portion in the radial direction;
The outer core portion has a plurality of outer core elements connected to the inner core portion through the plurality of connecting portions,
The resin part is
An upper resin portion covering at least part of the upper surface of the rotor core and at least part of the upper surface of each magnet;
A lower resin portion covering at least part of the lower surface of the rotor core and at least part of the lower surface of each magnet;
With
The resin portion further includes an annular inner peripheral resin portion that covers an inner peripheral surface of the rotor core,
The upper resin portion and the lower resin portion are continuous with the inner peripheral resin portion,
The bearing mechanism or the shaft is a motor held by the inner peripheral resin portion. The stationary part includes the shaft,
The bearing mechanism includes an upper bearing and a lower bearing,
The resin portion further includes an annular inner peripheral resin portion that covers at least a part of the inner peripheral surface of the rotor core,
The inner peripheral resin portion is continuous with at least one of the upper resin portion and the lower resin portion,
The motor according to claim 1, wherein one of the upper bearing and the lower bearing is held by the inner peripheral resin portion. The inner peripheral portion of the rotor core includes a core large diameter portion and a core small diameter portion,
The inner resin part is
A resin large diameter portion covering the core large diameter portion;
A resin small diameter part covering the core small diameter part;
A resin step portion between the resin large diameter portion and the resin small diameter portion;
Including
The motor according to claim 2, wherein the one bearing is held by the resin large diameter portion and is in contact with the resin stepped portion. The diameter of the inner periphery of the rotor core is constant,
The inner resin part is
A resin large-diameter portion covering the inner peripheral portion of the rotor core;
Covering the inner peripheral portion of the rotor core, a resin small diameter portion whose inner diameter is smaller than the inner diameter of the resin large diameter portion,
A resin step portion between the resin large diameter portion and the resin small diameter portion;
Including
The motor according to claim 2, wherein the one bearing is held by the resin large diameter portion and is in contact with the resin stepped portion. The resin part has a cylindrical shape centering on the central axis, and further includes a cylindrical resin part protruding in a direction away from the rotor core,
The motor according to any one of claims 2 to 4, wherein the other bearing of the upper bearing and the lower bearing is held by the cylindrical resin portion. The resin part further includes another cylindrical resin part covering the outer periphery of the cylindrical resin part,
The motor according to claim 5, wherein the cylindrical resin portion and the other cylindrical resin portion are connected in a radial direction by a plurality of rib portions.   The motor according to claim 5 or 6, wherein the resin portion includes an attachment portion for attaching an impeller cup around the cylindrical resin portion. A circuit board disposed perpendicular to the central axis;
An end portion on the one bearing side of the shaft is supported by the stationary portion,
The motor according to claim 2, wherein the circuit board is opposed to the end of the shaft in the axial direction.

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