JP6301662B2 - 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 has a plurality of claw-shaped magnetic poles in the circumferential direction and is combined, and field magnets are arranged between those axial directions to alternate each claw-shaped magnetic pole. A so-called permanent magnet field Landell-type rotor that allows different magnetic poles to function is known (for example, see Patent Document 1). Such a rotor is rotatably provided inside a stator having windings, and together with the stator, a case having a bottomed cylindrical yoke housing and a lid portion that closes the opening of the yoke housing. Be contained.

JP 2012-115085 A

  By the way, in the motor as described above, the yoke housing (the bottom portion) of the magnetic material is located on the one axial end surface side of the rotor. As a result, a part of the magnetic flux from the rotor field magnet may leak to the yoke housing, leading to a deterioration in 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-described problem is a stator core having a plurality of teeth extending radially inward, a stator having a winding wound around the teeth, and an outer periphery of a substantially disk-shaped core base, each at equal intervals A plurality of claw-shaped magnetic poles projecting radially outward and extending in the axial direction, and claw-shaped magnetic poles alternately arranged in the circumferential direction while facing each other's core base, And it is arranged between the axial directions of the core bases, and is magnetized in the axial direction, so that the claw-shaped magnetic pole of the first rotor core functions as a first magnetic pole, and the claw-shaped of the second rotor core. A rotor having a field magnet that functions as a second magnetic pole and rotatably provided inside the stator, a bottomed cylindrical yoke housing and a lid for closing the opening of the yoke housing A motor accommodated in a case having the bottomed cylindrical yoke housing has a cylindrical portion and a bottom portion, the cylindrical portion is made of a magnetic body, the axial direction of the rotor On both sides, the bottom portion of the yoke housing and the lid portion of the case are provided at positions facing the rotor in the axial direction, and the bottom portion located on one axial side of the rotor is nonmagnetic. The lid portion that is formed on the other side in the axial direction of the rotor is made of a nonmagnetic material .

  According to this configuration, since the bottomed cylindrical yoke housing has a magnetic body portion and a non-magnetic body portion, the magnetic body portion forms a part of the stator magnetic path, and the non-magnetic body portion of the rotor It is possible to suppress the leakage magnetic flux to the yoke housing. Therefore, output characteristics can be improved.

In the motor, the bottom portion made of the non-magnetic body portion is located on one side of the rotor in the axial direction of the field magnet, and on the other side of the rotor in the axial direction of the field magnet, The lid made of a nonmagnetic material is located.

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

Sectional drawing of the brushless motor in one Embodiment. The top view of the brushless motor in one Embodiment. The perspective view of the rotor in one Embodiment. Sectional drawing of the rotor in one Embodiment. Sectional drawing of the brushless motor in another example. Sectional drawing of the brushless motor in another example. (A), (b) is a schematic diagram for demonstrating the manufacturing method of the yoke housing in another example.

Hereinafter, an embodiment of a motor will be described with reference to FIGS.
As shown in FIG. 1, a case 12 of a brushless motor 11 as a motor is composed of a yoke housing 13 formed in a substantially bottomed cylindrical shape and a resin material that is a non-magnetic material that closes the opening of the yoke housing 13. And an end plate 14 as a lid.

  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 of this embodiment has 12 teeth 17a in the circumferential direction. 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. A winding 20 of U phase, V phase, and W phase is wound around the winding portion 18a by 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 at the shaft center L by bearings 23 and 24 supported at the bottom 13a of the yoke housing 13 and the centers of the end plates 14, respectively.

  As shown in FIGS. 3 and 4, the rotor 21 includes first and second rotor cores 31 and 32 that are fixed to the rotating shaft 22 while the axial distance between the rotating shafts 22 is maintained by press-fitting the rotating shaft 22. 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. 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 includes a plurality of (four in this embodiment) first claw-shaped magnetic poles 31 b at equal intervals 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 are press-fitted and fixed to the rotary shaft 22 by press-fitting the rotary shaft 22 into the central hole. 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 opposed axial directions.

  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). 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 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. Based on this, a driving current is supplied to the winding 20.

  Here, in the yoke housing 13 of the present embodiment, a magnetic body portion 51 made of iron which is a magnetic body and a nonmagnetic body portion 52 made of a nonmagnetic metal (such as stainless steel (SUS) or aluminum) which is a nonmagnetic body. And have.

  Specifically, the yoke housing 13 of the present embodiment is provided on a substantially cylindrical magnetic body portion 51 in which the stator 16 (stator core 17) is fitted, and on a surface facing the rotor 21 in the axial direction. And a substantially disk-shaped non-magnetic member 52 which is fixed to one opening of the magnetic member 51 and constitutes the bottom portion 13a. The non-magnetic member 52 has an edge 52a in which the magnetic member 51 can be fitted on the outer periphery thereof, and the end of the magnetic member 51 is fitted in the edge 52a and the portion is welded. This is fixed to the magnetic part 51.

  The non-magnetic member 52 includes a cylindrical portion 52b extending in a cylindrical shape toward the rotor 21 in the axial direction at a position facing the outer edge of the rotor 21, and extending radially inward from the distal end of the cylindrical portion 52b. An annular plate portion 52c facing the rotor 21 at a constant distance in the axial direction, and a bottomed cylindrical bearing housing portion 52d extending from the inner edge of the annular plate portion 52c to the side away from the rotor 21 in the axial direction. . The bearing 23 is accommodated and held in the bearing accommodating portion 52d.

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.

Next, the characteristic effects of the above embodiment will be described below.
(1) Since the bottomed cylindrical yoke housing 13 includes the magnetic body portion 51 and the nonmagnetic body portion 52, the magnetic body portion 51 forms a part of the magnetic path of the stator 16 while the nonmagnetic body portion 52 is configured. Thus, it is possible to suppress the leakage magnetic flux from the rotor 21 to the yoke housing 13. Therefore, output characteristics can be improved.

  (2) Since the nonmagnetic body portion 52 is provided on a surface facing the rotor 21 in the axial direction, the nonmagnetic body portion 52 is a surface facing the rotor 21 in the axial direction, and in this embodiment, the annular plate portion 52c is brought close to the rotor 21. The leakage magnetic flux to the yoke housing 13 of the rotor 21 can be suppressed while reducing the size of the brushless motor 11.

(3) Since the nonmagnetic body 52 is made of a nonmagnetic metal (stainless steel (SUS), aluminum, or the like), the strength of the portion can be ensured.
The above embodiment may be modified as follows.

  In the above-described embodiment, the yoke housing 13 includes the substantially cylindrical magnetic body 51 and the substantially disk-shaped nonmagnetic body that is fixed to one opening of the magnetic body 51 and forms the bottom portion 13 a of the yoke housing 13. Although it consists of the part 52, it is not limited to this, You may change into another structure. That is, as long as the leakage flux to the yoke housing of the rotor 21 can be suppressed by the non-magnetic member portion while forming a part of the magnetic path of the stator 16 by the magnetic member portion, another configuration may be used.

  For example, as shown in FIG. The yoke housing 13 in this example has the same overall shape as that of the above embodiment, but only the portion facing the rotor 21 in the axial direction, that is, only the portion corresponding to the annular plate portion 52c of the above embodiment is a non-magnetic material. A portion 61 is provided, and the other portions are magnetic body portions 62 and 63.

  If it does in this way, the nonmagnetic body part 61 can be decreased compared with the said embodiment. Therefore, for example, when the nonmagnetic body 61 is made of stainless steel (SUS), the material cost can be reduced.

  For example, as shown in FIG. The yoke housing 13 of this example has the same overall shape as that of the above embodiment, but the nonmagnetic body portion 71 is provided on the surface facing the rotor 21 in the axial direction, and the magnetic body portion 72 is provided on the back surface thereof. Are provided to form a two-layer structure. Note that the nonmagnetic body 71 of this example is provided on the entire inner surface of the case 12 in a portion substantially corresponding to the nonmagnetic body 52 (bottom portion 13a) of the above embodiment. Further, the yoke housing 13 of this example (see FIG. 6) is formed by cold forging as schematically shown in FIGS. 7 (a) and 7 (b). That is, as shown in FIG. 7A, the nonmagnetic material 73 and the magnetic material 74 are overlapped and pressed by the punch 75, so that the nonmagnetic material portion 71 and the magnetic material are shown in FIG. The yoke housing 13 having a two-layer structure of the portion 72 is formed.

  If it does in this way, the magnetic body part 72 can be kept away from the rotor 21 as much as the non-magnetic body part 71 is interposed between the rotor 21 and the leakage magnetic flux to the yoke housing 13 of the rotor 21 can be suppressed. And the nonmagnetic body part 71 can be decreased, for example, when the nonmagnetic body part 71 is comprised with stainless steel (SUS), material cost can be made cheap. Further, for example, even if the magnetic body portion 72 is thinned, the strength of the portion can be ensured by having a two-layer structure with the non-magnetic body portion 71.

  In the above embodiment, the nonmagnetic body 52 is made of a nonmagnetic metal (stainless steel (SUS), aluminum, etc.), but is not limited to this, and is made of a nonmagnetic resin material. May be.

  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. For example, the present invention may be embodied in a brushless motor in which the number of poles of the rotor 21 is set to “10” and the number of teeth 17a of the stator 16 is set to “12”.

In the above embodiment, the rotor 21 includes the back auxiliary magnets 34 and 35. However, the rotor 21 is not limited to this, and may be a rotor that does not include the back auxiliary magnets 34 and 35.
In the above embodiment, the rotor 21 includes the interpolar magnets 36 and 37. However, the present invention is not limited to this, and may be a rotor that does not include the interpolar magnets 36 and 37.

The technical idea that can be grasped from the above-described embodiments and the like will be described below together with the effects thereof.
(B) pre-Symbol nonmagnetic portion, characterized in that provided only in a portion opposed to the rotor in the axial direction.

  According to this configuration, since the nonmagnetic body portion is provided only in the portion facing the rotor in the axial direction, the nonmagnetic body portion can be reduced as much as possible. Therefore, for example, when the nonmagnetic part is made of stainless steel (SUS), the material cost can be reduced.

(B) pre-Symbol nonmagnetic part you characterized in that it is constituted by a non-magnetic metal.
According to this configuration, since the nonmagnetic body portion is made of a nonmagnetic metal (stainless steel (SUS), aluminum, or the like), the strength of the portion can be ensured.

  DESCRIPTION OF SYMBOLS 12 ... Case, 13 ... York housing, 14 ... End plate (lid part), 16 ... Stator, 17 ... Stator core, 17a ... Teeth, 20 ... Winding, 21 ... Rotor, 31 ... 1st rotor core, 31a ... 1st core Base (core base), 31b ... 1st claw-shaped magnetic pole (claw-shaped magnetic pole), 32 ... 2nd rotor core, 32a ... 2nd core base (core base), 32b ... 2nd claw-shaped magnetic pole (claw-shaped magnetic pole), 33 ... annular magnet (field magnet), 51, 62, 63, 72 ... magnetic body part, 52, 61, 71 ... non-magnetic body part.

Claims (2)

A stator core having a plurality of teeth extending radially inward, and a stator having a winding wound around the teeth;
A plurality of claw-shaped magnetic poles protrude outward in the radial direction at equal intervals on the outer periphery of the substantially disk-shaped core base and extend in the axial direction. The first and second rotor cores arranged alternately in the direction and the axial direction between the core bases are magnetized in the axial direction so that the claw-shaped magnetic poles of the first rotor core are first A rotor having a field magnet that allows the claw-shaped magnetic pole of the second rotor core to function as a second magnetic pole, and is rotatably provided inside the stator.
A motor housed in a case having a bottomed cylindrical yoke housing and a lid portion that closes an opening of the yoke housing,
The bottomed cylindrical yoke housing has a cylindrical part and a bottom part,
The cylindrical part is made of a magnetic part ,
On the both sides in the axial direction of the rotor, the bottom portion of the yoke housing and the lid portion of the case are provided at positions facing the rotor in the axial direction,
2. The motor according to claim 1, wherein the bottom portion located on one side in the axial direction of the rotor is made of a nonmagnetic material portion, and the lid portion located on the other side in the axial direction of the rotor is made of a nonmagnetic material . The motor according to claim 1,
On the one side in the axial direction of the field magnet of the rotor, the bottom portion made of the non-magnetic body portion is located,
The motor according to claim 1, wherein the lid portion made of a nonmagnetic material is positioned on the other axial side of the field magnet of the rotor.