JP6435758B2 - 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 field magnet of the rotor may leak to the case side (yoke housing side), leading to deterioration of output characteristics.

  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 suppressing leakage magnetic flux and improving output characteristics.

A motor that solves the above problems includes a stator core having a plurality of teeth extending in the circumferential direction in the circumferential direction, a stator having a winding wound around the teeth, and an outer peripheral portion of a substantially disk-shaped core base, etc. A plurality of claw-shaped magnetic poles projecting radially outward and extending in the axial direction at intervals, and first and second rotor cores having claw-shaped magnetic poles alternately arranged in the circumferential direction while facing each other's core base And the claw-shaped magnetic poles of the first rotor core function as the first magnetic poles by being arranged between the axial directions of the core bases and magnetized in the axial direction, and the claw-shaped of the second rotor core A rotor having a field magnet that causes a magnetic pole to function as a second magnetic pole is housed in a case having a bottomed cylindrical magnetic housing and a lid that closes the opening of the yoke housing. A motor, the yoke housing, the size of the cross section taken along the axial direction by forming a groove in at least a bottom portion is different configuration part.

  According to this configuration, the magnetoresistive resistance is increased at a portion having a small cross-sectional shape by making the cross-sectional size cut in the axial direction partially different at the bottom of the yoke housing. For this reason, leakage magnetic flux is suppressed and output characteristics can be improved.

According to the configuration of this, and the size of the cross section taken along the axial direction is different configuration part by forming a groove, so that the magnetic resistance increases in small part of the cross section. For this reason, leakage magnetic flux is suppressed and output characteristics can be improved.

  In the motor described above, the yoke housing may have a partially different cross-sectional size in the axial direction by forming the groove portion at a position facing the rotor in the axial direction in the axial direction or radially inward of the yoke housing. It is preferable to be configured.

  According to this configuration, the magnetic flux that leaks from the rotor having the field magnet that generates the main magnetic flux to the bottom of the yoke housing and the magnetic flux that leaks through the stator between the rotor and the yoke housing pass through. A groove is formed. For this reason, it is possible to reduce the leakage magnetic flux in advance at a location where the leakage magnetic flux tends to concentrate.

  In the motor, it is preferable that the yoke housing has a configuration in which a size of a cross section cut in an axial direction is partially different by forming the groove portion so as to open to the rotor side at the bottom portion.

  According to this configuration, since the groove portion is formed so as to open to the rotor side at the bottom portion, it can be separated from the rotor at a position where at least the groove portion of the bottom portion of the yoke housing is formed. Thereby, the magnetic flux which leaks from the rotor which has a field magnet which generates magnetic flux to the bottom of a yoke housing can be reduced.

  According to the motor of the present invention, leakage magnetic flux can be suppressed and output characteristics can be improved.

It is sectional drawing of the brushless motor in one Embodiment. It is a top view of the brushless 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 sectional drawing of the brushless motor in another example.

Hereinafter, an embodiment of the motor will be described.
As shown in FIG. 1, the case 12 of the brushless motor 11 includes a yoke housing 13 formed in a substantially bottomed cylindrical shape, and an end plate that closes an opening on the front side (left side in FIG. 1) of the yoke housing 13. 14. The yoke housing 13 is made of a magnetic material (for example, iron). The end plate 14 is made of a non-magnetic material (for example, a 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. Accordingly, the number of slots 17b formed between the teeth 17a is also twelve.
As shown in FIG. 2, the teeth 17 a include a winding portion 18 a and protruding portions 18 b that protrude from the radially inner end (tip) of the winding portion 18 a 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 FIGS. 1 and 2, 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 52 of the yoke housing 13 and the end plate 14.

  As shown in FIG. 3 and FIG. 4, the rotor 21 is fixed to the rotary shaft 22 while the interval in the axial direction (axis L direction) is maintained by press-fitting the rotary shaft 22. Two rotor cores 31 and 32 and an annular magnet 33 as a field magnet interposed between the first rotor core 31 and the second rotor core 32 in the axial direction are provided. 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 first rotor core 31 has a plurality of (five in the present embodiment) first claw-shaped magnetic poles 31 b on the outer periphery of the substantially disk-shaped first core base 31 a. Projecting outward in the radial direction and extending in the axial direction.

  As shown in FIGS. 3 and 4, the second rotor core 32 has the same shape as the first rotor core 31, and a plurality of second claws are arranged at equal intervals on the outer periphery of the substantially disk-shaped second core base 32 a. The magnetic pole 32b protrudes radially outward and extends in the axial direction. The first and second rotor cores 31 and 32 have the rotary shaft 22 press-fitted into their center holes, and the first and second core bases 31a and 32a have a distance in the axial direction outside (opposite sides) in advance. The rotary shaft 22 is press-fitted and fixed so as to have a set constant distance. At this time, the second rotor core 32 is arranged such that each of the second claw-shaped magnetic poles 32b is disposed between the first claw-shaped magnetic poles 31b adjacent in the circumferential direction, and the first core base 31a and the second core base 32a. The annular magnet 33 is assembled to the first rotor core 31 so as to be disposed (clamped) between the first rotor core 31 and the second rotor core 31.

  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, and functions as the first claw-shaped magnetic pole 31b as the first magnetic pole (N pole in the present embodiment). The second claw-shaped magnetic pole 32b is magnetized in the axial direction so as to function 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. In the rotor 21, four first claw-shaped magnetic poles 31b that are N poles and four second claw-shaped magnetic poles 32b that are S poles are alternately arranged in the circumferential direction, and the number of poles is eight (the number of pole pairs). Is 4).

  A back auxiliary magnet 34 is disposed between the back surface 31c (radially inner surface) of each first claw-shaped magnetic pole 31b and the outer peripheral surface 32d of the second core base 32a. The back auxiliary magnet 34 has a substantially fan-shaped cross section in the direction orthogonal to the axis, and the second core base 32a has a side that abuts on the back surface 31c of the first claw-shaped magnetic pole 31b and an N pole having the same polarity as the first claw-shaped magnetic pole 31b. Is magnetized so that the side in contact with the outer peripheral surface 32d becomes the S pole having the same polarity as the second core base 32a.

  Further, similarly to the first claw-shaped magnetic pole 31b, the back auxiliary magnet 35 is disposed between the back surface 32c of each second claw-shaped magnetic pole 32b and the outer peripheral surface 31d of the first core base 31a. The back auxiliary magnet 35 has a fan-shaped cross section in the direction perpendicular to the axis, and is magnetized so that the side in contact with the back surface 32c is an S pole and the side in contact with the outer peripheral surface 31d of the first core base 31a is an N pole. . 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 disposed between the circumferential directions of the first claw-shaped magnetic pole 31b and the second claw-shaped magnetic pole 32b.
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 is fixed on the side close to the first rotor core 31 with the boss portion 41 a fitted on the rotary shaft 22.

  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 yoke housing 13 of this embodiment will be described in detail.
The yoke housing 13 is configured to have a substantially bottomed cylindrical shape with a substantially cylindrical tubular portion 51 and a bottom portion 52 located at an end of the tubular portion 51.

The bottom 52 has a stator facing portion 53, a rotor facing portion 54, and a bearing housing portion 55.
The stator facing portion 53 is configured to be radially inward of the tubular portion 51 and continuous from the axial end portion of the tubular portion 51 and to face the stator 16 in the axial direction. The stator facing portion 53 is formed with a substantially annular groove 53 b on the facing surface 53 a side facing the stator 16. The groove 53b is formed so as to open to the stator 16 side facing in the axial direction. At this time, the surface 53c opposite to the facing surface 53a in which the groove 53b is formed is configured to be planar. That is, in the stator facing portion 53, the thickness T1 of the portion where the groove 53b is formed is thinner than the thickness T2 of the portion where the groove 53b is not formed, and the cross-sectional size cut in the axial direction is different. Is done.

  The rotor facing portion 54 is radially inward of the stator facing portion 53, and the rotor facing portion 54 is configured to face the rotor 21 in the axial direction. The rotor facing portion 54 is configured to be continuous from the stator facing portion 53 via the radially inner end of the stator facing portion 53 and the tubular portion 57. Further, the cylindrical portion 57 is configured to extend from the radially inner end of the stator facing portion 53 to the opening side (end plate 14 side) of the cylindrical portion 51, and at the tip thereof, the rotor It is comprised so that the edge part of the radial direction outer side of the opposing part 54 may be followed. Therefore, the rotor facing portion 54 is configured to be closer to the end plate 14 side (opening side of the yoke housing 13) in the axial direction than the stator facing portion 53.

  The rotor facing portion 54 is formed with a substantially annular groove portion 54 b on the facing surface 54 a side facing the rotor 21. The groove 54b is formed so as to open on the side of the rotor 21 facing in the axial direction. At this time, the surface 54c opposite to the facing surface 54a where the groove 54b is formed is configured to be planar. That is, in the rotor facing portion 54, the thickness T3 of the portion where the groove portion 54b is formed is thinner than the thickness T4 of the portion where the groove portion 54b is not formed, and the cross-sectional size cut in the axial direction is different. Is done.

The bearing accommodating portion 55 is configured to have a bottomed cylindrical shape so as to accommodate the bearing 23 inside the rotor facing portion 54 in the radial direction.
Next, the operation of the brushless motor 11 configured as described above will be described.

  In the brushless motor 11 of this embodiment, when a three-phase driving 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, the yoke housing 13 made of a magnetic material (made of iron) is positioned on one end surface side of the rotor 21 in the axial direction, and the end plate 14 made of resin is positioned on the other end surface side of the rotor 21 in the axial direction. There is a possibility that part of the magnetic flux from the magnet 33 leaks to the case 12 side (yoke housing 13 side) and the magnetic balance is lost.

  Therefore, in the present embodiment, grooves 53b and 54b are provided in the bottom 52 (stator facing portion 53 and rotor facing portion 54) of the yoke housing 13 that can be a magnetic path of leakage magnetic flux to reduce the cross-sectional size and increase the magnetic resistance. In this way, the leakage flux is likely to be saturated.

Next, the effect of this embodiment will be described.
(1) Since the size of the section cut in the axial direction at the bottom 52 of the yoke housing 13 is partially different, the magnetic resistance is increased at a portion having a small cross-sectional shape. For this reason, leakage magnetic flux is suppressed and output characteristics can be improved.

  (2) The groove portions 53b and 54b are formed in the bottom portion 52 so that the size of the cross section cut in the axial direction is partially different, and the magnetic resistance is increased at the small cross section. For this reason, leakage magnetic flux is suppressed and output characteristics can be improved.

  (3) Both the magnetic flux leaking from the rotor 21 having the annular magnet 33 that generates the main magnetic flux to the bottom 52 of the yoke housing 13 and the magnetic flux leaking through the stator 16 between the rotor 21 and the yoke housing 13 pass. A groove 54b is formed in the portion (the rotor facing portion 54). For this reason, it is possible to reduce the leakage magnetic flux in advance at a location where the leakage magnetic flux tends to concentrate.

  (4) Since the groove portion 54b is formed so as to open to the rotor 21 side at the bottom portion 52, it can be separated from the rotor 21 at a position where at least the groove portion 54b of the bottom portion 52 of the yoke housing 13 is formed. Thereby, the magnetic flux which leaks from the rotor 21 which has the annular magnet 33 which generate | occur | produces a magnetic flux to the bottom part 52 of the yoke housing 13 can be reduced.

  (5) Since the groove parts 53b and 54b are formed in an annular shape in the bottom part 52 of the yoke housing 13, the groove parts 53b and 54b are not interrupted in the circumferential direction, so that the leakage magnetic flux can be more reliably suppressed.

  (6) The magnetic flux leaking to the bottom 52 side via the cylindrical portion 51 of the yoke housing 13 can be suppressed by the groove 53b radially outside the position facing the rotor 21 in the axial direction.

In addition, you may change the said embodiment as follows.
In the above embodiment, when the grooves 53b and 54b are provided, the surfaces 53c and 54c opposite to the facing surfaces 53a and 54a are planar, but the present invention is not limited to this.

  As shown in FIG. 5, a configuration in which half-cut groove portions 58 and 59 are provided may be employed. In this case, with respect to the surfaces 53c and 54c opposite to the facing surfaces 53a and 54a, projecting surfaces 58a and 59a extending in the axial direction from the surfaces 53c and 54c are formed in the groove portions 58 and 59. It will be. At this time, as in the above embodiment, the thickness T5 of the portion where the groove portion 58 is formed in the stator facing portion 53 is thinner than the thickness T2 of the portion where the groove portion 58 is not formed, and the size of the cross section cut in the axial direction is small. The configuration is different. Similarly, in the rotor facing portion 54, the thickness T6 of the portion where the groove portion 59 is formed is thinner than the thickness T4 of the portion where the groove portion 59 is not formed, and the cross-sectional size cut in the axial direction is different. And

  In the above embodiment, the grooves 53b and 54b are formed so as to open to the stator 16 and the rotor 21 facing each other in the axial direction. However, the present invention is not limited to this. For example, the grooves 53b and 54b may be formed on the surfaces 53c and 54c opposite to the facing surfaces 53a and 54a. Moreover, you may employ | adopt the structure in which the magnitude | size of a cross section differs partially by forming a groove part in the opposing surfaces 53a and 54a and the surface 53c, 54c on the opposite side.

  In the above embodiment, the grooves 53b.. Are formed in both the stator facing portion 53 and the rotor facing portion 54. However, the present invention is not limited to this, and a configuration in which a groove portion is provided in one of the stator facing portion 53 and the rotor facing portion 54 may be employed.

  Further, although the single groove portions 53b and 54b are provided in both the stator facing portion 53 and the rotor facing portion 54, a configuration in which a plurality of groove portions are provided in at least one of the stator facing portion 53 and the rotor facing portion 54 is adopted. May be.

  In the above embodiment, the grooves 53b and 54b provided in the stator facing portion 53 and the rotor facing portion 54 are annular, but this is not restrictive. Moreover, it does not need to be annular. In short, it suffices that the portion that can partially become the magnetic path of the leakage magnetic flux can be reduced by making the cross-sectional sizes different.

  In the above embodiment, the groove portions 53b and 54b are provided in the stator facing portion 53 and the rotor facing portion 54. For example, a groove portion is provided in the cylindrical portion 57 between the stator facing portion 53 and the rotor facing portion 54. A configuration may be adopted.

-You may employ | adopt the structure which provides a groove part in the cylindrical part 51 in addition to the bottom part 52. FIG.
-You may combine the said embodiment and said each other example suitably.
Next, a technical idea that can be grasped from the above embodiment and another example will be added below.

(Appendix 1)
Before SL grooves, circumferentially continuous, characterized in that it is formed so as to form an annular shape.

Thus, by forming the annular groove at the bottom of the yoke housing, the groove is not interrupted in the circumferential direction, so that the leakage magnetic flux can be more reliably suppressed.
(Appendix 2)
Before SL yoke housing, the size of the cross section taken along the axial direction is different from configuration part by forming the groove in the radially outer side than a position facing the said rotor and the axial direction of the bottom it shall be the features a.

  Thereby, the magnetic flux leaking to the bottom side via the cylindrical portion of the yoke housing can be suppressed by the groove portion on the radially outer side than the position facing the rotor in the axial direction.

  DESCRIPTION OF SYMBOLS 11 ... Motor, 12 ... Case, 13 ... Yoke housing, 14 ... End plate as a cover part, 16 ... Stator, 17 ... Stator core, 17a ... Teeth, 20 ... Winding, 21 ... Rotor, 31, 32 ... Rotor core, 31 ... 1st rotor core, 31b, 32b ... Claw-shaped magnetic pole, 32 ... 2nd rotor core, 52 ... Bottom part, 53 ... Stator opposing part which comprises bottom part, 53b ... Groove part, 54 ... Rotor opposing part which comprises bottom part, 54b ... Groove part 55 ... Bearing housing portion constituting the bottom, 58 ... groove portion, 59 ... groove portion.

Claims (3)

A stator core having a plurality of radially extending teeth in the circumferential direction, and a stator having a winding wound around the teeth;
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 are first And a field magnet that causes the claw-shaped magnetic pole of the second rotor core to function as the second magnetic pole,
A motor housed in a case having a bottomed cylindrical magnetic housing and a lid for closing the opening of the yoke housing;
The motor is characterized in that the yoke housing has a groove part at least at the bottom so that the size of the section cut in the axial direction is partially different. The motor according to claim 1 ,
The yoke housing is configured such that the size of a cross section cut in the axial direction is partially different by forming the groove portion at a position facing the rotor at the bottom in the axial direction or radially inward of the yoke housing. A motor characterized by that. The motor according to claim 1 or 2 ,
The yoke housing has a configuration in which a size of a cross section cut in an axial direction is partially different by forming the groove portion so as to open to the rotor side at the bottom portion.