JP6330217B2 - motor - Google Patents

Description

  The present invention relates to a motor that houses a stator and a rotor in a case.

  Conventionally, a rotor core used in a motor has a rotor core that is combined with a plurality of claw-shaped magnetic poles in the circumferential direction, and field magnets are arranged between them to make the claw-shaped magnetic poles alternately different magnetic poles. A so-called permanent magnet field Landell-type rotor is known (for example, see Patent Document 1).

  In addition, in the Landel-type rotor, in order to increase the output of the motor, an interpole magnet for rectifying a magnetic path between alternately arranged claw-shaped magnetic poles has been proposed. (For example, refer to Patent Document 2). In such a motor, the rotor and the stator are housed in a case having a bottomed cylindrical yoke housing and an end frame provided at one end of the yoke housing.

Japanese Utility Model Publication No. 5-43749 JP 2012-115085 A

  By the way, in the motor as described above, the yoke housing made of magnetic material is positioned on the one axial end surface side of the rotor, and the resin end frame is positioned on the other axial end surface side of the rotor. In this case, a part of the magnetic flux from the rotor field magnet leaks to the case side (yoke housing side), an imbalance of the magnetic flux amount occurs between the N pole and the S pole, and the cogging torque becomes unbalanced and the sound It may cause deterioration of vibrations.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a motor capable of improving the cogging torque balance.

A motor that solves the above problems includes a stator core and a stator having windings, and a plurality of claw-shaped magnetic poles projecting radially outward at equal intervals on the outer periphery of a substantially disk-shaped core base and in the axial direction. The first and second rotor cores, which are extended and formed so that the claw-shaped magnetic poles are alternately arranged in the circumferential direction with the core bases facing each other, are arranged between the axial directions of the core bases, and A rotor having a field magnet that is magnetized so that the claw-shaped magnetic pole of the first rotor core functions as a first magnetic pole and the claw-shaped magnetic pole of the second rotor core functions as a second magnetic pole; , a motor housed in a case having a lid of the non-magnetic material for closing the yoke housing and the opening of the yoke housing of a magnetic material in a bottomed cylindrical shape, the core base of the first rotor core in the axial direction And the circumferential width of the outermost peripheral portion of the claw-shaped magnetic pole of the first rotor core is equal to the circumference of the outermost peripheral portion of the claw-shaped magnetic pole of the second rotor core. It is configured wider than the direction width.

  According to this configuration, the circumferential width of the outermost peripheral portion of the claw-shaped magnetic pole of one rotor core is configured to be wider than the circumferential width of the outermost peripheral portion of the claw-shaped magnetic pole of the other rotor core. The torque component of the rotor core on the side far from the housing can be reduced. As a result, the rotor core closer to the yoke housing in the axial direction generates a leakage magnetic flux on the yoke housing side, so that the cogging torque balance is improved even if the torque component of the rotor core on the side different from the yoke housing is reduced. it can.

  In the motor, both circumferential sides on the outer peripheral side of the claw-shaped magnetic pole of the second rotor core are chamfered or R-curved, and the circumferential width of the outermost peripheral portion of the claw-shaped magnetic pole of the first rotor core is the second width. It is preferable that the circumferential width of the outermost peripheral portion of the claw-shaped magnetic pole of the rotor core is wider.

  According to this configuration, it is possible to change only the circumferential width of the outermost peripheral portion and make the circumferential width the same for each rotor core with respect to the root portion that is the radially inner portion of the claw-shaped magnetic pole. This makes it possible to secure the magnetic path area with a good balance.

  According to the motor of the present invention, the cogging torque can be well balanced.

It is sectional drawing of the motor in embodiment. It is a top view of the motor in the same as the above. It is a perspective view of the rotor in the same as the above. It is sectional drawing of the rotor in the same as the above. It is a top view of the rotor in the same as the above. It is a graph for demonstrating the cogging torque of the rotor in the same as the above. It is a top view of the rotor in another example.

Hereinafter, an embodiment of the motor will be described.
As shown in FIG. 1, a motor case 12 of a brushless motor 11 as a motor includes a yoke housing 13 formed in a substantially bottomed cylindrical shape, and an opening on the front side (left side in FIG. 1) of the yoke housing 13. And an end plate 14 as a lid portion for closing. The yoke housing 13 is made of, for example, magnetic iron. The end plate 14 is made of, for example, a non-magnetic resin material.

  As shown in FIG. 1, a stator 16 is fixed to the inner peripheral surface of the yoke housing 13. The stator 16 includes a stator core 17 having a plurality of teeth 17 a extending radially inward, and a winding 20 wound around the teeth 17 a of the stator core 17 via an insulator 19. The stator 16 generates a rotating magnetic field when a drive current is supplied from the external control circuit S to the winding 20.

As shown in FIG. 2, the stator core 17 has a total of 12 teeth 17a. Therefore, the number of slots 17b formed between the teeth 17a is also twelve.
As shown in FIG. 2, the teeth 17a include a winding portion 18a and protruding portions 18b that protrude from the radially inner end of the winding portion 18a to both sides in the circumferential direction. In the winding portion 18a, the U-phase, V-phase, and W-phase windings 20 are wound in concentrated winding.

  As shown in FIG. 1, the rotor 21 of the brushless motor 11 has a rotating shaft 22 and is disposed inside the stator 16. The rotating shaft 22 is a non-magnetic metal shaft, and is rotatably supported by bearings 23 and 24 supported by the bottom 13 a of the yoke housing 13 and the end plate 14.

  As shown in FIGS. 3 and 4, the rotor 21 includes a pair of rotor cores 31 and 32 that are fixed to the rotary shaft 22 while maintaining the axial distance therebetween by press-fitting the rotary shaft 22. An annular magnet 33 is provided as a field magnet interposed between the axial directions of the rotor cores 31 and 32. Further, the rotor 21 includes back auxiliary magnets 34 and 35 and interpole magnets 36 and 37.

  As shown in FIGS. 3 and 4, the rotor core 31 has a plurality of (four in this embodiment) claw-shaped magnetic poles 31 b protruding outward in the radial direction at equal intervals on the outer periphery of a substantially disc-shaped core base 31 a. And extending in the axial direction. Specifically, the claw-shaped magnetic pole 31b has a protrusion 31c that protrudes radially outward from the outer periphery of the core base 31a, and a claw 31d that is provided at the tip of the protrusion 31c and extends in the axial direction. The protrusion 31c is formed in a fan shape when viewed from the axial direction. The claw portion 31d has a fan-shaped cross section in the direction perpendicular to the axis. Further, as shown in FIG. 5, the radially outer surface 31g of the claw-shaped magnetic pole 31b (claw portion 31d) has an arc shape that passes on the same circumference centered on the rotor center O when viewed in the axial direction. Formed as follows.

  As shown in FIGS. 3 and 4, the rotor core 32 has a plurality of claw-shaped magnetic poles 32b projecting radially outward at equal intervals on the outer periphery of a substantially disk-shaped core base 32a and extending in the axial direction. Is formed. Specifically, the claw-shaped magnetic pole 32b has a protrusion 32c that protrudes radially outward from the outer periphery of the core base 32a, and a claw 32d that is provided at the tip of the protrusion 32c and extends in the axial direction. The protruding portion 32 c is formed in a fan shape when viewed from the axial direction, like the protruding portion 31 c of the rotor core 31. The claw portion 32d has a fan-shaped cross section in the direction perpendicular to the axis. Further, as shown in FIG. 5, the radially outer surface 32g of the claw-shaped magnetic pole 32b (claw portion 32d) has an arc shape that passes on the same circumference around the rotor center O when viewed in the axial direction. It is formed to make.

  As shown in FIG. 5, the claw-shaped magnetic pole 32b of one rotor core 32 has a circumferential width W1 of the radially outer surface 32g thereof and a circumferential width W2 of the radially outer surface 31g of the claw-shaped magnetic pole 31b of the other rotor core 31. Longer than configured. The circumferential width W1 is defined by a virtual line VL1 connecting the rotor center O and one corner Ka1 in the circumferential direction of the radially outer surface 32g, and the other circumferential direction of the rotor center O and the radially outer surface 32g. This is the angle width formed by the virtual line VL2 connecting the corner portion Ka2. The circumferential width W2 is an imaginary line VL3 connecting the rotor center O and one corner Ka3 of the radially outer surface 31g, and the other corner in the circumferential direction of the rotor center O and the radially outer surface 31g. This is the angle width formed by the virtual line VL4 connecting the part Ka4.

  Each of the rotor cores 31 and 32 configured as described above has the rotary shaft 22 press-fitted into the center hole thereof, and the distance between the outer sides (opposite sides) of the core bases 31a and 32a in the axial direction is set in advance. The rotary shaft 22 is press-fitted and fixed so as to be a distance. At this time, the rotor core 32 is arranged so that the claw-shaped magnetic pole 32b is disposed between the claw-shaped magnetic poles 31b of the other rotor core 31 adjacent in the circumferential direction and between the core base 31a and the core base 32a. The annular magnet 33 is assembled to the rotor core 31 so as to be disposed (clamped).

  The annular magnet 33 is a magnet such as a ferrite magnet or a neodymium magnet, and is formed in an annular shape having a central hole. The claw-shaped magnetic pole 31b of the rotor core 31 is used as a first magnetic pole (N pole in this embodiment). It is magnetized in the axial direction so that the claw-shaped magnetic pole 32b of the rotor core 32 functions as a second magnetic pole (S pole in this embodiment). That is, the rotor 21 of the present embodiment is a so-called Landell type rotor using an annular magnet 33 as a field magnet. The rotor 21 has four claw-shaped magnetic poles 31b serving as N poles and four claw-shaped magnetic poles 32b serving as S poles arranged alternately in the circumferential direction, and has eight poles (four pole pairs). It becomes. That is, in the present embodiment, the number of poles of the rotor 21 is set to “8”, and the number of teeth 17a of the stator 16 is set to “12”.

  A back auxiliary magnet 34 is disposed between the back surface 31 e (radially inner surface) of each claw-shaped magnetic pole 31 b of the rotor core 31 and the outer peripheral surface 32 f of the core base 32 a of the rotor core 32. The back auxiliary magnet 34 has a substantially fan-shaped cross section in the direction perpendicular to the axis, the side contacting the back surface 31e of the claw-shaped magnetic pole 31b is an N pole having the same polarity as the claw-shaped magnetic pole 31b, and the outer peripheral surface of the core base 32a of the rotor core 32 The side abutting on 32f is magnetized so as to be the south pole of the same polarity as the core base 32a.

  A back auxiliary magnet 35 is disposed between the back surface 32 e of each claw-shaped magnetic pole 32 b of the rotor core 32 and the outer peripheral surface 31 f of the core base 31 a of the rotor core 31. The back auxiliary magnet 35 has a fan-shaped cross section in the direction perpendicular to the axis, the side contacting the back surface 32e of the claw-shaped magnetic pole 32b is the S pole, and the side contacting the outer peripheral surface 31f of the core base 31a of the rotor core 31 is the N pole. So that it is magnetized. As the back auxiliary magnets 34 and 35, for example, ferrite magnets can be used.

As shown in FIGS. 2 and 3, interpolar magnets 36 and 37 are arranged between the claw-shaped magnetic pole 31b and the claw-shaped magnetic pole 32b in the circumferential direction.
In the rotor 21 configured as described above, the core base 32a of one rotor core 32 is arranged closer to the yoke housing 13 (bottom 13a side) in the axial direction than the core base 31a of the other rotor core 31. For this reason, the rotor core 32 corresponds to a first rotor core, and the rotor core 31 corresponds to a second rotor core.

  As shown in FIG. 1, the rotor 21 is provided with a sensor magnet 42 via a substantially disc-shaped magnet fixing member 41. Specifically, the magnet fixing member 41 includes a disc portion 41b having a boss portion 41a formed at the center, and a cylinder portion 41c extending in a cylindrical shape from the outer edge of the disc portion 41b. An annular sensor magnet 42 is fixed so as to come into contact with the peripheral surface and the surface of the disc portion 41b. The magnet fixing member 41 has a boss portion 41 a that is externally fitted to the rotary shaft 22 and fixed on the side close to the rotor core 31.

  In the end plate 14, a Hall IC 43 as a magnetic sensor is provided at a position facing the sensor magnet 42 in the axial direction. When the Hall IC 43 senses the N-pole and S-pole magnetic fields based on the sensor magnet 42, it outputs an H level detection signal and an L level detection signal to the control circuit S, respectively.

Next, the operation of the brushless motor 11 configured as described above will be described.
When a three-phase drive current is supplied from the control circuit S to the winding 20, a rotating magnetic field is generated in the stator 16, and the rotor 21 is driven to rotate. At this time, as the sensor magnet 42 facing the Hall IC 43 rotates, the level of the detection signal output from the Hall IC 43 is switched according to the rotation angle (position) of the rotor 21, and the control circuit S is based on the detection signal. To the winding 20 is supplied with a three-phase drive current that switches at an optimal timing. As a result, a rotating magnetic field is generated satisfactorily, and the rotor 21 is driven to rotate continuously.

  Here, for example, consider a case where the circumferential widths of the radially outer surfaces 31g, 32g of the claw-shaped magnetic poles 31b, 32b of the rotor cores 31, 32 are substantially the same. In this case, in the rotor core 31 that is far from the yoke housing 13 (bottom portion 13a) in the axial direction, there is almost no leakage magnetic flux between the yoke housing 13 and the rotor core 31, so that the cogging torque increases as shown by X1 in FIG. Cheap. On the other hand, in the rotor core 32 that is close to the yoke housing 13 (bottom portion 13a) in the axial direction, a leakage magnetic flux is generated between the yoke housing 13 and the rotor core 32, so that the cogging torque tends to be low as indicated by X2 in FIG. For this reason, the cogging torque is unbalanced between the N pole and the S pole.

  Therefore, as described above, the rotor core 32 that is disposed relatively close to the yoke housing 13 in the axial direction has the circumferential width W1 of the radially outer surface 32g of the claw-shaped magnetic pole 32b outside the radial direction of the other rotor core 31. The side surface 31g is formed wider than the circumferential width W2 (W1> W2). As a result, since the claw-shaped magnetic pole 31b of the rotor core 31 with less leakage magnetic flux has a narrower circumferential width than the claw-shaped magnetic pole 32b of the other rotor core 32, the amount of magnetic flux acting between the stator 16 is reduced. As shown by Y1 in 6, the cogging torque can be reduced. As a result, the difference from the cogging torque of the other pole indicated by Y2 in FIG. 6 is reduced, and the cogging torque is balanced.

  Further, the rotor core 31 that is relatively far from the yoke housing 13 has a small amount of magnetic flux leaking to the yoke housing 13, so that a sufficient amount of magnetic flux is secured even if the circumferential width W2 of the radially outer surface 31g of the claw-shaped magnetic pole 31b is narrowed. It can be done.

Next, the effect of this embodiment will be described.
(1) The circumferential width W1 of the radially outer surface 32g as the outermost peripheral portion of the claw-shaped magnetic pole 32b of one rotor core 32 is the radial outer surface 31g as the outermost peripheral portion of the claw-shaped magnetic pole 31b of the other rotor core 31. It is configured wider than the circumferential width W2. For this reason, the torque component (cogging torque) of the rotor core 31 on the side far from the yoke housing 13 in the axial direction can be reduced. As a result, the rotor core 32 on the side close to the yoke housing 13 in the axial direction also reduces the torque component of the rotor core 31 on the side different from the yoke housing 13 even if leakage magnetic flux is generated on the yoke housing 13 side. Can be good.

In addition, you may change the said embodiment as follows.
Although not particularly mentioned in the above embodiment, for example, the circumferential widths W1 and W2 of the radially outer surfaces 31g and 32g of the claw-shaped magnetic poles 31b and 32b may be different by the following configuration.

  As shown in FIG. 7, by chamfering (C chamfering) both sides in the radial direction of the claw-shaped magnetic pole 31b (claw portion 31d) of the rotor core 31 in the radial direction, the circumferential width W2 of the radial outer surface 31g is set to the other side. The rotor core 32 is formed to be narrower (W1> W2) than the circumferential width W1 of the radially outer surface 32g. In addition, the rotor core 31 is relatively spaced apart from the yoke housing 13 (bottom part 13a) in the axial direction like the rotor core 31 of the above embodiment. With such a configuration, the circumferential widths W3 and W4 of each of the claw-shaped magnetic poles 31b and 32b are set to the widths W3 and W4 in the circumferential direction of the root portion (the boundary portion with the core bases 31a and 32a). It is possible to make the same in 31b and 32b (each rotor core 31 and 32). This makes it possible to secure the magnetic path area with a good balance.

  In addition, the circumferential width W2 of the radially outer surface 31g is narrower than the circumferential width W1 of the radially outer surface 32g of the other rotor core 32 (W1> W2) by making both sides in the circumferential direction R-shaped. Also good.

  In the above embodiment, the brushless motor is embodied in which the number of poles of the rotor 21 is set to “8” and the number of teeth 17a of the stator 16 is set to “12”, but the number of poles of the rotor 21 and the stator 16 The number of teeth 17a may be changed.

  In the above embodiment, the back auxiliary magnets 34 and 35 and the interpolar magnets 36 and 37 are provided on the rotor 21, but this is not a limitation. For example, a configuration in which only the back auxiliary magnet is provided, a configuration in which only the interpole magnet is provided, or a configuration in which the back auxiliary magnet and the interpole magnet are omitted may be employed.

  In the above embodiment, the winding 20 is wound around the teeth 17a of the stator 16. However, the present invention is not limited to this. For example, a configuration may be adopted in which a stator core that is combined with a plurality of claw-shaped magnetic poles in the circumferential direction is provided, and windings are arranged between them to alternately function the claw-shaped magnetic poles to different magnetic poles. .

  -You may combine the said embodiment and each modification suitably.

  DESCRIPTION OF SYMBOLS 11 ... Motor, 13 ... Yoke housing, 16 ... Stator, 17 ... Stator core, 20 ... Winding, 21 ... Rotor, 31 ... Rotor core (second rotor core), 31a ... Core base, 31b ... Claw-shaped magnetic pole, 31g ... Radial direction Outer side surface (outermost peripheral portion), 32 ... rotor core (first rotor core), 32a ... core base, 32b ... claw-shaped magnetic pole, 32g ... radially outer side surface (outermost peripheral portion), 33 ... annular magnet (field magnet), W1, W2 ... Circumferential width.

Claims (2)

A stator having a stator core and windings;
A plurality of claw-shaped magnetic poles project radially outward and extend in the axial direction on the outer periphery of each substantially disk-shaped core base, and the claw-shaped magnetic poles are formed with the core bases facing each other. The first and second rotor cores arranged alternately in the circumferential direction and the core bases are arranged between the axial directions and magnetized in the axial direction, so that the claw-shaped magnetic poles of the first rotor core can be A rotor having a field magnet that functions as the first magnetic pole and functions as the second magnetic pole of the claw-shaped magnetic pole of the second rotor core;
A motor accommodated in a case having a bottomed cylindrical magnetic housing and a non-magnetic lid that closes the opening of the yoke housing,
When the core base of the first rotor core is disposed on the yoke housing side with respect to the core base of the second rotor core in the axial direction, the circumferential width of the outermost peripheral portion of the claw-shaped magnetic pole of the first rotor core is the second rotor core. A motor characterized in that it is configured to be wider than the circumferential width of the outermost peripheral portion of the claw-shaped magnetic pole. The motor according to claim 1,
Both sides in the circumferential direction on the outer peripheral side of the claw-shaped magnetic pole of the second rotor core are chamfered or R-curved, and the circumferential width of the outermost peripheral portion of the claw-shaped magnetic pole of the first rotor core is claw-shaped on the second rotor core. A motor configured to be wider than a circumferential width of an outermost peripheral portion of a magnetic pole.