JP2012023833A - Motor and rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor which can increase torque.SOLUTION: A motor M includes: a stator 10 provided with a plurality of teeth 11a extending radially inward to be arranged in a circumferential direction and wound around with coils; and a rotor 20 which is arranged inside the stator 10, provided with a plurality of magnets 23 of one pole in a circumferential direction of a rotor core 22, and has salient poles 22b on the rotor core 22 arranged between each of the magnets 23 with gaps to function as the other pole. Axial lengths of tips of the teeth 11a are set to be longer than those of the magnets 23 (magnet pole parts) in the rotor 20.

Description

  The present invention relates to a motor and a rotor that employ a continuous pole type structure.

  As a rotor used in a motor, for example, as shown in Patent Document 1, a plurality of magnets having one magnetic pole are arranged in the circumferential direction of a rotor core, and salient poles formed integrally with the core are disposed between the magnets. A rotor having a so-called contiguous pole structure is known which is arranged and allows the salient pole to function as the other magnetic pole.

JP 9-327139 A

  By the way, a rotor having a consequent pole type structure as in Patent Document 1 is composed of a magnetic pole in which a magnet having a magnetic flux forcing force (induction) and a salient pole without a magnetic flux forcing force coexist. For this reason, ideally, the magnetic flux that passes between the salient pole and the stator (the tip of the tooth) and links the teeth (linkage magnetic flux) goes in the other direction, and the motor torque As a result, the leakage flux does not contribute to the motor, and as a result, the torque of the motor is reduced.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a motor and a rotor capable of achieving high torque.

  In order to solve the above problems, in the invention according to claim 1, a plurality of teeth extending radially inward are provided in the circumferential direction, and a winding is wound around the teeth; A plurality of magnets having one magnetic pole are arranged in the circumferential direction of the rotor core, and salient poles provided on the rotor core are arranged with gaps between the magnets so that the salient pole functions as the other magnetic pole. The axial length of the tip end portion of the teeth is greater than the axial length of the magnet pole portion that is the radially outer end portion of the rotor at a position corresponding to the magnet. The gist is that it was set for a long time.

  According to this configuration, the axial length of the tip end portion of the teeth is set longer than the axial length of the magnet pole portion, which is the radially outer end portion at a position corresponding to the magnet in the rotor. The gap permeance between the rotor and the stator can be increased. As a result, the leakage magnetic flux is reduced, and the stator linkage magnetic flux is increased. As a result, high torque can be achieved.

  According to a second aspect of the present invention, in the motor according to the first aspect, an axial protrusion amount A of the tip portion of the teeth with respect to the magnet pole portion, and a radial gap distance between the stator and the rotor. The gist is that the ratio A / B to B is set so as to satisfy 0 <(A / B) ≦ 1.5.

  According to this configuration, the ratio A / B between the axial protrusion amount A with respect to the magnet pole portion at the tip portion of the tooth and the radial gap distance B between the stator and the rotor is 0 <(A / B). Since it is set so as to satisfy ≦ 1.5, the stator interlinkage magnetic flux is larger than when the tip portion of the teeth does not protrude in the axial direction with respect to the magnet pole portion (when A / B = 0) ( (See FIG. 3). Therefore, high torque can be achieved. In addition, in the range of 0 <(A / B) ≦ 1.5, the stator linkage flux increases as the ratio A / B (projection amount A) increases (see FIG. 3). There is no lengthening in the axial direction.

  According to a third aspect of the present invention, in the motor according to the first aspect, an axial protrusion amount A with respect to the magnet pole portion of the tip portion of the teeth, and a radial gap distance between the stator and the rotor The gist is that the ratio A / B to B is set to satisfy 1.5 ≦ (A / B) ≦ 2.5.

  According to this configuration, the ratio A / B between the axial protrusion amount A with respect to the magnet pole portion at the tip portion of the tooth and the radial gap distance B between the stator and the rotor is 1.5 ≦ (A / B) Since the setting is made so as to satisfy ≦ 2.5, the stator interlinkage magnetic flux is larger than that in the case where the tip end portion of the teeth does not protrude axially with respect to the magnet pole portion (when A / B = 0) (See FIG. 3). Therefore, high torque can be achieved. Moreover, in the range of 1.5 ≦ (A / B) ≦ 2.5, the stator interlinkage magnetic flux is almost the maximum value (see FIG. 3), and the teeth are as in the case where the ratio A / B exceeds 2.5. There is no need to lengthen the tip of the shaft significantly in the axial direction. Therefore, for example, if the design is made with (A / B) = 2.0 ± 0.5, the maximum linkage torque can be easily set to the maximum value without any significant waste and the maximum torque can be easily increased.

  In the invention according to claim 4, a plurality of magnets of one magnetic pole are arranged in the circumferential direction of the rotor core, salient poles provided on the rotor core are arranged with gaps between the magnets, and the salient poles are arranged on the other magnet. A rotor configured to function as a magnetic pole, wherein an axial length of the salient pole is set longer than an axial length of a magnet pole portion that is a radially outer end portion at a position corresponding to the magnet. This is the summary.

  According to this configuration, since the axial length of the salient pole is set to be longer than the axial length of the magnet pole portion, which is the radially outer end at the position corresponding to the magnet, the salient pole is longer than the magnet pole portion. The gap permeance with the stator (tip portion of the teeth) arranged to face in the radial direction can be increased by the portion protruding in the axial direction. As a result, the leakage magnetic flux is reduced, and the stator linkage magnetic flux is increased. As a result, high torque can be achieved.

  According to a fifth aspect of the present invention, the rotor according to the fourth aspect and a plurality of teeth extending radially inward so as to face the rotor in the radial direction are provided in the circumferential direction, and windings are wound around the teeth. And a ratio C / B between an axial projection amount C of the salient pole with respect to the magnet pole portion and a radial gap distance B between the stator and the rotor. , 0 <(C / B) <2 is set.

  According to this configuration, the ratio C / B between the axial protrusion amount C of the salient pole with respect to the magnet pole portion and the radial gap distance B between the stator and the rotor is 0 <(C / B) <2. Therefore, the stator interlinkage magnetic flux is larger than when the salient pole does not protrude in the axial direction with respect to the magnet pole portion (when C / B = 0) (see FIG. 6). Therefore, high torque can be achieved.

  ADVANTAGE OF THE INVENTION According to this invention, the motor and rotor which can achieve high torque can be provided.

The top view of the motor in 1st Embodiment. Sectional drawing of the motor in 1st Embodiment. The characteristic view which shows the relationship between ratio A / B and a stator linkage magnetic flux. The perspective view of the rotor in 2nd Embodiment. Sectional drawing of the motor in 2nd Embodiment. The characteristic view which shows the relationship between ratio C / B and a stator flux linkage. (A), (b) Partial sectional drawing for demonstrating the motor in another example.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows an inner rotor type brushless motor (hereinafter simply referred to as a motor) M. As shown in FIG. 1, the stator 10 of the motor M is wound around the teeth 11 a and a stator core 11 in which a plurality of teeth 11 a extending inward in the radial direction (12 in the present embodiment) are provided in the circumferential direction. Winding 12 is provided.

  In addition, the rotor 20 disposed inside the stator 10 in the motor M has a substantially annular rotor core 22 that is externally fitted to the outer peripheral surface of the rotating shaft 21 as shown in FIG. Seven magnet arrangement portions 22a are formed on the outer peripheral portion of the rotor core 22 in the circumferential direction (at equal angular intervals), and N pole magnets 23 are arranged in the magnet arrangement portion 22a (seven in total). ing. In addition, between the magnets 23, salient poles 22b provided on the outer peripheral portion of the rotor core 22 (integrated in the present embodiment) are respectively connected to the boundary portions with the magnets 23 (in the axial direction in the present embodiment). It is arranged with a gap K (having a constant area when viewed from above). That is, the magnets 23 and the salient poles 22b are alternately arranged at equiangular (360 ° / 14) intervals, and the rotor 20 is a so-called 14-pole magnetic pole that causes the N-pole magnet 23 to function as the S pole. It is composed of a consequent pole type. Note that the rotor 20 of the present embodiment is a surface magnet type in which the magnet 23 is disposed at the radially outer end (outer peripheral surface) of the rotor 20, and the magnet 23 becomes the magnet pole portion of the rotor 20 as it is. .

  Here, the axial length of the tip (radially inner end) of the tooth 11a is set longer than the axial length of the magnet 23 (magnet pole portion) in the rotor 20, as shown in FIG. Yes. In the present embodiment, the axial length of the distal end portion of the teeth 11a is the same as the axial length of other portions of the stator core 11 (other than the distal end portion of the teeth 11a and the annular portion). The direction length is set to be the same as the axial length of the rotor core 22 (including the salient poles 22b). In FIG. 2, illustration of the winding 12 wound around the teeth 11 a is omitted.

  And in this Embodiment, as shown in FIG. 2, the protrusion amount A of the axial direction with respect to the magnet 23 (magnet pole part) of the front-end | tip part (radial inner side edge part) of the teeth 11a, the stator 10, the rotor 20, The ratio A / B with the (shortest) radial gap distance B is set to satisfy 1.5 ≦ (A / B) ≦ 2.5. Note that the tip of the tooth 11a protrudes in the axial direction by the protruding amount A at both ends in the axial direction with respect to the magnet 23 (magnet pole portion), and the axial length of the tip of the tooth 11a is the magnet. That is, the length is set to be twice (A × 2) the projection amount A than the axial length of 23 (magnet pole portion).

Next, characteristic actions and effects of the first embodiment will be described below.
(1) Since the axial length of the tip portion of the tooth 11a is set to be longer than the axial length of the magnet 23 (magnet pole portion) in the rotor 20, the gap permeance between the rotor 20 and the stator 10 at this portion is set. Can be increased. As a result, the leakage magnetic flux is reduced and the stator interlinkage magnetic flux (specifically, the magnetic flux interlinking the teeth 11a of the stator 10) is increased, so that high torque can be achieved.

  (2) The ratio A / B between the axial protrusion amount A with respect to the magnet 23 (magnet pole portion) at the tip of the tooth 11a and the radial gap distance B between the stator 10 and the rotor 20 is 1.5. It is set to satisfy ≦ (A / B) ≦ 2.5. As a result, the stator interlinkage magnetic flux increases compared to the case where the tip end portion of the tooth 11a does not protrude in the axial direction with respect to the magnet 23 (magnet pole portion) (in the case of A / B = 0) (see FIG. 3). Therefore, high torque can be achieved. Moreover, in the range of 1.5 ≦ (A / B) ≦ 2.5, the stator interlinkage magnetic flux is almost the maximum value (see FIG. 3), and the teeth are as in the case where the ratio A / B exceeds 2.5. The tip of 11a is not significantly lengthened in the axial direction. Therefore, for example, if the design is made with (A / B) = 2.0 ± 0.5, the maximum linkage torque can be easily set to the maximum value without any significant waste and the maximum torque can be easily increased. Specifically, FIG. 3 shows the stator flux linkage (ratio) when the ratio A / B is changed by experiment. As shown in FIG. 3, when the ratio A / B satisfies 1.5 ≦ (A / B) ≦ 2.5, the axial length of the tip portion of the tooth 11a and the axis of the magnet 23 (magnet pole portion). It can be seen that the stator interlinkage magnetic flux is substantially the maximum value (about 101%) as compared with the case where the direction length is the same (when A / B = 0). Therefore, in the present embodiment, the ratio A / B is set to satisfy 1.5 ≦ (A / B) ≦ 2.5.

(Second Embodiment)
A second embodiment embodying the present invention will be described below with reference to FIGS. In the second embodiment, portions similar to those in the first embodiment (stator 10 and the like) are denoted by the same reference numerals, and a detailed description thereof is partially omitted.

  In the rotor 30 of this example, as shown in FIGS. 4 and 5, the axial length of the salient pole 31a (salient pole member 31) is set longer than the axial length of the magnet 23 (magnet pole portion). ing. Specifically, the salient pole 31 a in this example is formed on the salient pole member 31 that is formed separately from the rotor core 32 and is fixed to the rotor core 32. The axial length of the salient pole member 31 is longer than the axial lengths of the magnet 23 (magnet pole portion) and the rotor core 32.

  Then, as shown in FIG. 5, the ratio between the protruding amount C of the salient pole 31 a in the axial direction with respect to the magnet 23 (magnet pole portion) and the distance B of the (shortest) radial gap between the stator 10 and the rotor 30. C / B is set to satisfy 0 <(C / B) <2. In addition, the salient pole 31a (the salient pole member 31) projects by the projection amount C in the axial direction on both ends in the axial direction with respect to the magnet 23 (magnet pole portion), and the salient pole 31a (the salient pole member 31) Is set to be longer than the axial length of the magnet 23 (magnet pole portion) by twice the projection amount C (C × 2). Further, the axial length of the stator core 11 (the tip portion of the teeth 11a) in this example is shorter than the axial length of the salient pole 31a (the salient pole member 31) as shown in FIG. It is set longer than the axial length of the pole portion).

Next, characteristic effects (other than those described above) of the second embodiment will be described below.
(1) Since the axial length of the salient pole 31 a (the salient pole member 31) is set longer than the axial length of the magnet 23 (magnet pole portion), the salient pole 31 a (the salient pole member 31) becomes the magnet 23. The gap permeance with the stator 10 (tip portion of the teeth 11a) can be increased by the portion protruding in the axial direction from the (magnet pole portion). As a result, the leakage magnetic flux is reduced, and the stator linkage magnetic flux is increased. As a result, high torque can be achieved.

  (2) The ratio C / B between the axial protrusion amount C of the salient pole 31a with respect to the magnet 23 (magnet pole portion) and the radial gap distance B between the stator 10 and the rotor 30 is 0 <(C / B) Since it is set to satisfy <2, the stator interlinkage magnetic flux is larger than when the salient pole 31a does not protrude in the axial direction with respect to the magnet 23 (when C / B = 0) (FIG. 6). reference). Therefore, high torque can be achieved. Specifically, FIG. 6 shows the stator flux linkage (ratio) when the ratio C / B is changed by experiment. As shown in FIG. 6, when the ratio C / B satisfies 0 <(C / B) <2, the axial length of the salient pole 31a (the salient pole member 31) and the axis of the magnet 23 (magnet pole portion). It can be seen that the stator interlinkage magnetic flux increases as compared with the case where the direction length is the same (C / B = 0). Therefore, in this example, the ratio C / B is set so as to satisfy 0 <(C / B) <2. As shown in FIG. 6, when the ratio C / B satisfies 0.5 ≦ (C / B) ≦ 1.0, the stator linkage magnetic flux becomes substantially the maximum value (about 101.5%). I understand that. Therefore, it is particularly desirable that the ratio C / B is set so as to satisfy 0.5 ≦ (C / B) ≦ 1.0. In this way, the maximum torque can be increased.

The above embodiment may be modified as follows.
In the first embodiment, the ratio A between the axial protrusion amount A with respect to the magnet 23 (magnet pole portion) at the tip of the tooth 11a and the radial gap distance B between the stator 10 and the rotor 20 / B is set to satisfy 1.5 ≦ (A / B) ≦ 2.5, but is not limited to this, for example, set to satisfy 0 <(A / B) ≦ 1.5 May be.

  Even if it does in this way, stator interlinkage magnetic flux will increase rather than the case where the front-end | tip part of the teeth 11a does not protrude in the axial direction with respect to the magnet 23 (magnet pole part) (when A / B = 0) (FIG. 3). reference). Therefore, high torque can be achieved. In addition, in the range of 0 <(A / B) ≦ 1.5, the stator linkage flux increases as the ratio A / B (projection amount A) increases (see FIG. 3). Is not lengthened in the axial direction. Specifically, FIG. 3 shows the stator flux linkage (ratio) when the ratio A / B is changed by experiment. As shown in FIG. 3, when the ratio A / B satisfies 0 <(A / B) ≦ 1.5, the axial length of the tip portion of the tooth 11a and the axial length of the magnet 23 (magnet pole portion). It can be seen that the stator linkage flux increases as the ratio A / B increases as the stator linkage flux increases and the ratio A / B increases. Therefore, in this example, the ratio A / B is set to satisfy 0 <(A / B) ≦ 1.5.

  In the first embodiment, the axial length of the tip portion of the teeth 11a is the same as the axial length of other portions of the stator core 11 (other than the tip portion of the teeth 11a and the annular portion). However, the present invention is not limited to this, and for example, as shown in FIGS. 7A and 7B, only the tip portion of the tooth 11a may be changed so that the axial length becomes longer.

  Specifically, in the first embodiment, the detailed configuration of the stator core 11 is not particularly mentioned. However, as shown in FIG. 7A, only the tip end portion (the radially inner end portion) of the teeth 11a in the stator core 41 is provided. The stator core 41 may be manufactured by SMC molding or the like so that the axial length becomes long.

  Further, as shown in FIG. 7B, substantially the entire stator core 42 is manufactured by laminating the core sheet S, and only the tip end portion (the radially inner end portion) of the teeth 11a has an increased axial length. As described above, another member 42a may be fixed to the portion.

  If it does in this way, while being able to acquire the effect similar to the effect of 1st Embodiment, it can suppress the protrusion amount of the axial direction of the coil | winding 12 (refer FIG. 1) wound by the teeth 11a. As a result, it is possible to reduce the size of the motor M in the axial direction.

  In the above embodiments, the rotors 20 and 30 are of the surface magnet type in which the magnets 23 are disposed at the radially outer ends (outer peripheral surfaces) of the rotors 20 and 30. You may change to a magnet-type rotor. In this case, the magnet pole portion that faces the stator (tip of the tooth 11a) in the radial direction is a radially outer end portion at a position corresponding to the magnet in the rotor core. Therefore, for example, when the rotor 20 of the first embodiment is changed to an embedded magnet type rotor, the axial length of the tip of the tooth 11a is set to the diameter of this magnet pole portion (position corresponding to the magnet in the rotor core). It is set to be longer than the axial length of the outer end portion in the direction.

  In each of the embodiments described above, the motor M is embodied with 12 teeth 11a (12 slots) and 7 magnets 23 (ie, salient poles 22b and 31a) (ie, 14 magnetic poles). The motor may be changed to this.

  DESCRIPTION OF SYMBOLS 10 ... Stator, 11a ... Teeth, 12 ... Winding, 20, 30 ... Rotor, 22, 32 ... Rotor core, 22b, 31a ... Salient pole, 23 ... Magnet, A, C ... Projection amount, B ... Distance, K ... Air gap .

Claims (5)

A plurality of teeth extending radially inward in the circumferential direction, and a stator having a winding wound around the teeth;
A plurality of magnets of one magnetic pole are arranged in the circumferential direction of the rotor core, arranged inside the stator, and salient poles provided on the rotor core are arranged with gaps between the magnets, and the salient poles are arranged as the other magnetic poles. A motor with a rotor configured to function as
The motor is characterized in that the axial length of the tip end portion of the teeth is set longer than the axial length of the magnet pole portion which is a radially outer end portion at a position corresponding to the magnet in the rotor. The motor according to claim 1,
The ratio A / B between the axial protrusion amount A of the tip portion of the teeth with respect to the magnet pole portion and the radial gap distance B between the stator and the rotor is as follows:
0 <(A / B) ≦ 1.5
A motor characterized by being set to satisfy. The motor according to claim 1,
The ratio A / B between the axial protrusion amount A of the tip portion of the teeth with respect to the magnet pole portion and the radial gap distance B between the stator and the rotor is as follows:
1.5 ≦ (A / B) ≦ 2.5
A motor characterized by being set to satisfy. A plurality of magnets of one magnetic pole are arranged in the circumferential direction of the rotor core, and salient poles provided on the rotor core are arranged with gaps between the magnets, and the salient pole functions as the other magnetic pole. A rotor,
The rotor characterized in that the axial length of the salient pole is set longer than the axial length of the magnet pole portion which is a radially outer end portion at a position corresponding to the magnet. A rotor according to claim 4;
A motor including a plurality of teeth extending radially inward so as to face the rotor in the radial direction, and a stator having a winding wound around the teeth,
A ratio C / B between an axial protrusion amount C of the salient pole with respect to the magnet pole portion and a radial gap distance B between the stator and the rotor is:
A motor set to satisfy 0 <(C / B) <2.

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