JP2005287285A - Motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor that provides higher torque while preventing the generation of cogging torque. <P>SOLUTION: The motor comprises a slotless stator 2 in which a binding 5 is arranged along the inner peripheral wall 4a of a yoke 4, and a rotor 3 where a plurality of permanent magnets are provided in the circumferential direction at a rotor core 11 that is rotatably provided inside the stator 2. The permanent magnet is a V-shape permanent magnet 13 that is arranged in an almost V-like protrusion, in the radial direction, in the rotor core 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a brushless motor.

Conventionally, there is a slotless motor as a brushless motor (see Patent Document 1). This motor has a slotless (coreless) stator in which windings are disposed along the inner peripheral wall of the yoke, and a plurality of permanent magnets in the circumferential direction on the outer peripheral surface of a rotor core that is rotatably provided inside the stator. And a rotor. In such a slotless (coreless) motor, generation of cogging torque is prevented (cogging torque is zero in principle).
JP 2003-319597 A

However, in the slotless motor as described above, the generation of cogging torque is prevented, but it is difficult to increase the torque.
The present invention has been made to solve the above problems, and an object of the present invention is to provide a motor capable of increasing the torque while preventing the occurrence of cogging torque.

  According to the first aspect of the present invention, a plurality of permanent magnets are provided in the circumferential direction on a slotless stator in which windings are disposed along the inner peripheral wall of the yoke and a rotor core that is rotatably provided inside the stator. The permanent magnet is a V-shaped permanent magnet that is arranged in a substantially V-shape projecting radially inward inside the rotor core.

According to a second aspect of the present invention, in the motor of the first aspect, the V-shaped permanent magnet is formed by arranging a pair of quadrangular prism-shaped permanent magnets in a substantially V-shape.
According to a third aspect of the present invention, in the motor according to the second aspect, the rotor core has a pair of accommodating holes for receiving the pair of permanent magnets in a substantially V-shape projecting radially inward. A plurality of inner side extending portions are formed on the radially inner ends of the pair of receiving holes so as to reduce leakage magnetic flux at the radially inner ends of the pair of receiving holes. On the side away from each other at the radially inner end, the wall surface forming the accommodation hole positions the permanent magnet in the longitudinal direction.

  According to a fourth aspect of the present invention, in the motor according to the third aspect, the rotor core is formed by laminating a plurality of core sheets in the axial direction, and an interval Ta between the adjacent inner extending portions is , Tb ≦ Ta ≦ 2Tb (where Tb is the thickness of one core sheet).

According to a fifth aspect of the present invention, in the motor according to the third or fourth aspect, the axial thickness of the bridge portion formed between the adjacent inner extending portions is made thinner than the other portions.
According to a sixth aspect of the present invention, in the motor according to any one of the first to fifth aspects, the axial length of the cylindrical portion forming the inner peripheral wall of the yoke is greater than the axial length of the rotor core. Set long.

According to a seventh aspect of the present invention, in the motor according to any one of the first to sixth aspects, the cylindrical portion of the yoke is formed by laminating annular silicon steel plates.
According to an eighth aspect of the present invention, in the motor according to any one of the first to seventh aspects, the winding is a flat copper wire.

(Function)
According to the first aspect of the present invention, since the stator is a slotless one in which the winding is disposed along the inner peripheral wall of the yoke, generation of cogging torque is prevented. And since a permanent magnet is a V-shaped permanent magnet arrange | positioned inside a rotor core at the substantially V shape convex radially inward, a reluctance torque can be utilized effectively. Further, since the permanent magnet is a V-shaped permanent magnet as described above, the amount of the permanent magnet is increased as compared with a curved permanent magnet that is disposed along the circumferential direction (on the outer peripheral surface of the rotor core). be able to. From these things, high torque can be achieved.

  According to the second aspect of the present invention, the V-shaped permanent magnet is formed by arranging a pair of quadrangular prism-shaped permanent magnets in a substantially V-shape, so that the rotor can be easily made using a simple-shaped permanent magnet. Can get to.

  According to the third aspect of the present invention, the radially inner end portions of the pair of receiving holes are formed with the inner extending portions for reducing the leakage magnetic flux extending from the sides adjacent to each other. (Magnetic flux heading from the N pole of the magnet to its own S pole) is reduced. Therefore, higher torque can be achieved. Further, the bridge portion is formed as a part of the rotor core between the adjacent inner extending portions, thereby increasing the rigidity of the rotor core. Moreover, since the permanent magnets are positioned in the longitudinal direction on the wall surfaces forming the accommodation holes on the radially inner ends of the pair of accommodation holes, rattling of the permanent magnets is prevented. Therefore, it is possible to prevent the permanent magnet from colliding with the bridge portion, and it is possible to prevent the bridge portion from being deformed. Further, since the position of the permanent magnet is stabilized, a stable torque characteristic (output) can be obtained.

  According to the invention described in claim 4, the interval Ta between the adjacent inner extending portions is set to satisfy Tb ≦ Ta ≦ 2Tb (where Tb is the thickness of one core sheet). Therefore, the leakage magnetic flux can be reduced while maintaining the rigidity of the rotor core (bridge portion).

According to the fifth aspect of the present invention, since the axial thickness of the bridge portion formed between the adjacent inner extending portions is made thinner than other portions, the leakage magnetic flux is further reduced.
According to the sixth aspect of the present invention, since the axial length of the cylindrical portion forming the inner peripheral wall of the yoke is set longer than the axial length of the rotor core, the magnetic saturation of the yoke is alleviated.

According to the seventh aspect of the present invention, since the cylindrical portion of the yoke is formed by laminating the annular silicon steel plates, the iron loss in the yoke can be reduced.
According to the eighth aspect of the present invention, since the winding is a flat copper wire, the gap generated between the windings can be reduced, and the magnetic gap can be reduced.

  As described above in detail, according to the present invention, it is possible to provide a motor capable of increasing the torque while preventing the generation of cogging torque.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the motor 1 includes a stator 2 and a rotor 3.
The stator 2 is slotless (coreless), and includes a pair of end housings E (see FIG. 2) that constitute a part of the housing of the motor 1, a yoke 4 that also constitutes a part of the housing, And a winding 5 disposed along the inner peripheral wall 4 a of the yoke 4. The yoke 4 of the present embodiment is entirely cylindrical and constitutes a cylindrical portion. Further, the yoke 4 of the present embodiment is formed in a cylindrical shape by laminating a plurality of annular silicon steel plates in the axial direction. In FIG. 2, illustration of the boundary line between the silicon steel plates is omitted. End housings E are fixed to both ends of the yoke 4 in the axial direction so as to close the openings. The winding 5 is disposed so that a plurality of rings are formed in the circumferential direction, and is fixed (sealed) to the inner peripheral wall 4 a of the yoke 4 with a mold resin material 6. In FIG. 1, hatching of the winding 5 and the mold resin material 6 is omitted. In FIG. 2, the winding 5 and the mold resin material 6 are schematically illustrated collectively, and hatching thereof is omitted. Further, as shown in FIG. 2, the winding 5 and the mold resin material 6 of the present embodiment are set such that the axial length thereof is shorter than the axial length of the yoke 4 (cylinder portion). Both end portions in the axial direction of the yoke 4 are arranged so as to protrude in the axial direction from the winding 5 and the mold resin material 6.

  The rotor 3 includes a rotor core 11, a rotating shaft 12, and a plurality of V-shaped permanent magnets 13, and the rotating shaft 12 is disposed with respect to the pair of end housings E so that the rotor core 11 is disposed inside the winding 5. And is rotatably supported.

  The rotor core 11 is formed by laminating a plurality of disk-shaped core sheets. In addition, in FIG. 2, illustration of the boundary line between core sheets is abbreviate | omitted. As shown in FIG. 2, the rotor core 11 is set such that its axial length is shorter than the axial length of the yoke 4 (tubular portion) and the axial length of the winding 5 and the mold resin material 6. Both end portions in the axial direction of the yoke 4 and both end portions in the axial direction of the winding 5 and the mold resin material 6 are arranged so as to protrude from the rotor core 11 in the axial direction. Further, as shown in FIG. 1, a center hole 11 a into which the rotating shaft 12 is fitted is formed at the axial center of the rotor core 11.

  The rotor core 11 is formed with six pairs of receiving holes 21a and 21b that are substantially V-shaped and protrude inward in the radial direction. At both ends of each of the receiving holes 21a and 21b, there are an inner extension portion 22 and an outer extension portion 23 that are extended to reduce leakage magnetic flux (magnetic flux that immediately goes from the N pole of the magnet toward its own S pole) ( As part of the hole) (see FIG. 3). Specifically, as shown in FIG. 3, the radially inner ends of the pair of receiving holes 21 a and 21 b extend from the sides close to each other (substantially half of the ends) so as to reduce the leakage magnetic flux. An installation portion 22 is formed. The pair of inner extending portions 22 are formed so that their closest portions extend in parallel (in the radial direction). Further, the interval between adjacent inner extending portions 22 (the width of the bridge portion 24 formed between the adjacent inner extending portions 22) Ta is equal to or greater than the plate thickness Tb (not shown) of the core sheet. Is set so as to satisfy twice or less (Tb ≦ Ta ≦ 2Tb). In this embodiment, the interval Ta is set to be equal to the plate thickness Tb. In addition, an outer extending portion 23 is formed at the radially outer end portion of the pair of receiving holes 21a and 21b so as to extend from the sides close to each other to reduce the leakage magnetic flux.

  And in the accommodation holes 21a and 21b (excluding the inner extension portion 22 and the outer extension portion 23), the V-shaped permanent magnets 13 arranged in a substantially V shape convex radially inward are accommodated and held. . In the present embodiment, the V-shaped permanent magnet 13 is arranged in a substantially V shape by accommodating a pair of quadrangular prism-shaped permanent magnets 25a, 25b in the accommodation holes 21a, 21b. As shown in FIG. 3, the permanent magnets 25 a and 25 b are arranged on the wall surfaces 26 that form the receiving holes 21 a and 21 b on the side of the pair of receiving holes 21 a and 21 b that are spaced apart from each other in the radial direction (in the axial direction). Positioning in the longitudinal direction is performed. That is, the wall surface 26 on the side where the inner extending portion 22 is not formed serves as a stopper that restricts the movement of the permanent magnets 25a and 25b on the closer side in the longitudinal direction. Further, in the present embodiment, like the wall surface 26, a role of a stopper that restricts the movement of the wall surface 27 on the side of the permanent magnets 25a and 25b in the longitudinal direction at the radially outer ends of the receiving holes 21a and 21b. Plays. The adjacent V-shaped permanent magnets 13 are set so that the N pole and the S pole are reversed.

  In the motor 1 configured as described above, the magnet torque between the rotating magnetic field generated by the stator 2 based on the current supply to the winding 5 and the rotor 3, and the V-shaped permanent magnet 13 in the rotor 3, specifically the rotor core 11. The rotor 3 is rotationally driven by the reluctance torque based on the magnetic path formed on the inner side (radially outer side).

Next, characteristic effects of the above embodiment will be described below.
(1) Since the stator 2 is a slotless type in which the winding 5 is disposed along the inner peripheral wall 4a of the yoke 4, the generation of cogging torque is prevented (the cogging torque is zero in principle). ) Moreover, since the permanent magnet provided in the rotor 3 is a V-shaped permanent magnet 13 arranged in a substantially V shape convex radially inward inside the rotor core 11, the inner side of the V-shaped permanent magnet 13 (outside in the radial direction). ), The reluctance torque based on the magnetic path formed can be effectively used. In addition, the amount of the V-shaped permanent magnet 13 can be increased as compared with a curved permanent magnet that is disposed along the circumferential direction (on the outer circumferential surface of the rotor core). From these things, the torque of the motor 1 can be increased.

  (2) Since the V-shaped permanent magnet 13 is arranged in a substantially V shape by accommodating a pair of quadrangular prism-shaped permanent magnets 25a and 25b in the accommodating holes 21a and 21b, the permanent magnet having a simple shape The rotor 3 can be easily obtained using 25a and 25b.

  (3) Inner extending portions 22 are formed at the radially inner ends of the pair of receiving holes 21a and 21b so as to extend from the sides close to each other (substantially half of the ends) to reduce leakage magnetic flux. For this reason, the leakage magnetic flux (magnetic flux heading from the N pole of the magnet to the S pole of itself) is reduced. Therefore, higher torque can be achieved. Further, since the bridge portion 24 is formed between the adjacent inner extending portions 22, for example, the rigidity of the rotor core 11 is higher than in the case where the accommodation holes are formed in a continuous V shape (not a pair). Become. Further, on the side of the pair of receiving holes 21a and 21b that are separated from each other at the radially inner ends, the wall surface 26 that forms the receiving holes 21a and 21b (as viewed from the axial direction) in the longitudinal direction of the permanent magnets 25a and 25b. Since positioning is performed, rattling of the permanent magnets 25a and 25b is prevented. Therefore, it is possible to prevent the permanent magnets 25a and 25b from colliding with the bridge portion 24 and to prevent the bridge portion 24 from being deformed. Further, since the positions of the permanent magnets 25a and 25b are stabilized, a stable torque characteristic (output) can be obtained.

  (4) Since the interval between the adjacent inner extending portions 22 (the width of the bridge portion 24 formed between the adjacent inner extending portions) Ta is set to be the same as the plate thickness Tb (not shown) of the core sheet. The leakage magnetic flux can be reduced while maintaining the rigidity of the rotor core 11 (bridge portion 24).

  (5) Since the axial length of the yoke 4 (cylindrical portion) is set longer than the axial length of the rotor core 11, magnetic saturation of the yoke 4 is alleviated. Therefore, higher torque can be achieved. Further, since both end portions in the axial direction of the yoke 4 (cylindrical portion) are arranged so as to protrude in the axial direction from the winding 5 and the molding resin material 6 and the rotor core 11, the shape of the end housing E is simplified, Assembling of the end housing E to the yoke 4 (end portion in the axial direction) can be facilitated. In other words, for example, if both end portions in the axial direction of the yoke 4 (cylinder portion) do not protrude from the rotor core 11 in the axial direction, the shape and assembly of the end housing become complicated, but this can be avoided.

  (6) Since yoke 4 (cylinder part) is formed by laminating annular silicon steel plates, iron loss in yoke 4 can be reduced. Therefore, it is possible to make the motor 1 particularly suitable for the use of a product that performs high-speed operation.

The above embodiment may be modified as follows.
In the above embodiment, the bridge portion 24 is formed with the same thickness as the other portions of the rotor core 11, but as shown in FIG. 4, the bridge portion 31 has a step with the other portions, and its axial direction The thickness may not be thinner than other portions. If it does in this way, the cross-sectional area of the bridge part 31 will become small, and a leakage magnetic flux will become still smaller. Further, in this example, the thickness of the portion corresponding to the bridge portion 31 of each core sheet is made thinner than the other portions, so that the thickness of the bridge portion 31 in the axial direction (a plurality of axial portions formed in the axial direction) is reduced. The thickness excluding the gap is made thinner than the other parts. Therefore, for example, the rotor core can be easily formed by crushing a portion corresponding to the bridge portion 31 of the core sheet with a press or the like.

  In the above embodiment and another example (see FIG. 4), the rotor core 11 is formed by laminating a plurality of disk-shaped core sheets, but may be formed by sintering magnetic powder. Good. In this way, the iron loss can be further reduced. In this case, the thickness of the bridge portion in the axial direction may be simply made thinner than other portions. Even if it does in this way, the cross-sectional area of a bridge | bridging part will become small and a leakage magnetic flux will become still smaller.

  In the above embodiment, the winding 5 has a circular cross section. However, the present invention is not limited to this, and the winding 41 may be a rectangular copper wire (the cross section is rectangular) as shown in FIG. The winding 41 (flat copper wire) in this example has a long side set larger than the diameter of the winding 5 in the above embodiment and a short side set smaller than the diameter of the winding 5 in the above embodiment. Yes. The winding 41 has a short side (flat direction) disposed along the radial direction of the yoke 4 in a cross section in the axis-perpendicular direction of the yoke 4 (see FIG. 5).

  In this way, the gap generated between the windings 41 can be reduced (compared to a circular cross section), and the magnetic gap can be reduced. Therefore, the magnetic flux can be used more effectively and higher torque can be achieved.

  In the above embodiment, the winding 5 (41) is fixed to the inner peripheral wall 4a of the yoke 4 with the mold resin material 6, but if it is fixed to the inner peripheral wall 4a of the yoke 4, The winding 5 (41) may be modified to be fixed by another structure.

  In the above embodiment, the inner extending portion 22 is formed at the radially inner ends of the pair of receiving holes 21a and 21b. However, the inner extending portion 22 is not formed. May be. The inner extending portion 22 can be changed to another shape as long as the wall surface is the same as the wall surface 26 for reducing the leakage magnetic flux and positioning the permanent magnets 25a and 25b in the longitudinal direction. Also good.

  -In said embodiment, when the space | interval (width | variety of the bridge | bridging part 24 formed between the adjacent inner extension parts) Ta is set to be the same as the plate | board thickness Tb of a core sheet | seat. However, it may be changed if the interval Ta between the adjacent inner extending portions 22 is set so as to satisfy the plate thickness Tb of the core sheet and not more than twice the plate thickness Tb (Tb ≦ Ta ≦ 2Tb). Even in this case, the leakage magnetic flux can be reduced while maintaining the rigidity of the rotor core 11.

  In the above embodiment, the V-shaped permanent magnet 13 is formed by arranging a pair of quadrangular prism-shaped permanent magnets 25a and 25b in a substantially V-shape, but a V-shaped permanent magnet integrally formed in a substantially V-shape. You may change to a magnet. In this case, it is necessary to change the shape of the receiving holes 21a and 21b according to the V-shaped permanent magnet.

  In the above embodiment, the yoke 4 (cylinder part) is formed by laminating an annular silicon steel plate, but is not limited to this, and other materials (materials) and other structures (through other manufacturing processes) It may be changed to (formed). For example, it may be changed to one using another annular steel plate. Especially when the material is low carbon steel, the magnetic resistance in the stacking direction is reduced (compared to a simple steel plate), and the magnetic saturation is relaxed. The Therefore, higher torque can be achieved. That is, the motor 1 can be made suitable for the use of a product that operates at low speed with high torque.

  In the above embodiment, the yoke 4 as a whole is cylindrical and has a cylindrical portion. However, the yoke has a bottomed cylindrical shape (a cylindrical cylindrical portion and a bottom portion that closes one end thereof). Shape).

-Numerical values, such as the number (six) of the V-shaped permanent magnet 13 (a pair of permanent magnet 25a, 25b) of the said embodiment, may be changed suitably.
The technical idea that can be grasped from the above embodiments will be described below together with the effects thereof.

  (A) In the motor according to claim 5, the rotor core is formed by laminating a plurality of core sheets in the axial direction, and a thickness of a portion corresponding to the bridge portion of each core sheet is different. The motor according to claim 1, wherein the thickness of the bridge portion in the axial direction is made thinner than that of the other portions. If it does in this way, a rotor core can be easily formed by crushing the part corresponding to the bridge part of a core sheet with a press etc., for example.

The principal part sectional drawing of the stator and rotor in this Embodiment. The schematic cross section of the motor in this Embodiment. FIG. 3 is a partially enlarged view of a rotor in the present embodiment. The partially enlarged view of the rotor in another example. Explanatory drawing for demonstrating the coil | winding in another example.

Explanation of symbols

  2 ... Stator, 3 ... Rotor, 4 ... Yoke (cylindrical part), 4a ... Inner wall, 5, 41 ... Winding, 11 ... Rotor core, 13 ... V-shaped permanent magnet, 21a, 21b ... Housing hole, 22 ... Inside extension Installation part, 25a, 25b ... Permanent magnet, 26 ... Wall surface, 31 ... Bridge part.

Claims (8)

A slotless stator in which windings are disposed along the inner peripheral wall of the yoke;
A rotor core provided rotatably inside the stator, and a rotor having a plurality of permanent magnets provided in a circumferential direction;
The motor according to claim 1, wherein the permanent magnet is a V-shaped permanent magnet arranged in a substantially V shape convex radially inward inside the rotor core. The motor according to claim 1,
The V-shaped permanent magnet includes a pair of quadrangular prism-shaped permanent magnets arranged in a substantially V shape. The motor according to claim 2,
The rotor core is formed with a plurality of housing holes arranged in the circumferential direction in a pair of a pair of the permanent magnets, each having a substantially V-shape projecting radially inward in a pair.
On the radially inner ends of the pair of receiving holes, an inner extending portion is formed to extend from the sides adjacent to each other to reduce leakage magnetic flux,
The motor characterized in that the wall surface forming the accommodation hole positions the permanent magnet in the longitudinal direction on the side of the pair of accommodation holes at the radially inner ends. The motor according to claim 3, wherein
The rotor core is formed by laminating a plurality of core sheets in the axial direction,
The interval Ta between the adjacent inner extending portions is:
Tb ≦ Ta ≦ 2Tb (where Tb is the thickness of one core sheet)
A motor characterized by being set to satisfy. The motor according to claim 3 or 4,
A motor in which an axial thickness of a bridge portion formed between adjacent inner extending portions is thinner than other portions. The motor according to any one of claims 1 to 5,
The motor according to claim 1, wherein an axial length of a cylindrical portion forming the inner peripheral wall of the yoke is set longer than an axial length of the rotor core. The motor according to any one of claims 1 to 6,
The motor is characterized in that the cylindrical portion of the yoke is formed by laminating annular silicon steel plates. The motor according to any one of claims 1 to 7,
A motor characterized in that the winding is a rectangular copper wire.

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