JP2012249469A - Axial gap type motor and in-wheel motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an axial gap type motor with a compact structure.SOLUTION: A rotor 10 comprises: a magnetization region 10a having plural magnetization parts 12 magnetized to exhibit a magnetic pole along a peripheral edge 19 of an end face 11a; and a detection region 10b having plural detection parts (recesses) 13 for a proximity sensor 30 to detect a rotary position of the magnetization parts 12 corresponding to a projection pole set 25 so that an energization state of a stator coil 26 wound around the projection pole set 25 is switched corresponding to the rotary position of the magnetization parts 12. Furthermore, the detection region 10b is arranged on the inner side than the magnetization region 10a.

Description

  The present invention relates to an axial gap type motor and an in-wheel motor provided with the same.

  Patent Document 1 describes that an axial motor and an in-wheel motor that can be provided with a rotation detection function at a low cost while minimizing the size increase are described. Therefore, Patent Document 1 discloses that an annular output side stator, a rotor, and a counter output side stator having magnetic cores arranged in the circumferential direction are arranged to face each other in the rotation axis direction, and the output side stator, the rotor, and the counter output side stator are arranged. In the axial motor in which the motor housing is housed, a groove is formed integrally on the outer peripheral surface of the rotor, provided with an unevenness detecting portion for detecting the groove, and a detector support hole is provided in the motor housing so as to face the outer peripheral surface of the rotor. It is described that the unevenness detecting portion is inserted into the detector support hole.

JP 2008-295212 A

  In recent years, an electric vehicle driven by an electric motor has been put into practical use, and an in-wheel motor in which an electric motor is disposed in the wheel of the vehicle has been proposed. An axial gap type motor in which a stator and a rotor are opposed to each other with a gap in the direction of the rotation axis of the rotor is suitable for an in-wheel motor because it can easily adopt a large-diameter rotor and can be thinned as a whole.

  In the technique disclosed in Patent Document 1, a groove is formed on the outer peripheral surface of the rotor. For this reason, it is necessary to provide the uneven | corrugated detection part which detects a groove part in the radial direction outer side of a rotor so that the outer peripheral surface of a rotor may be opposed. Therefore, while it is possible to make the whole thin, it is demanded to provide an axial motor having a more compact configuration because the radial dimension of the axial motor tends to increase.

  One aspect of the present invention is an axial gap type motor having a disk-shaped rotor that rotates around an axis and a pair of stators disposed on both sides in the axial direction of the rotor. The rotor includes a magnetized region in which a plurality of magnetized portions magnetized so that magnetic poles appear on both end faces in the axial direction are arranged along the peripheral edges of the both end faces. It includes a plurality of stator coils arranged to face the magnetic region. The rotor further includes a plurality of detection units that provide a rotational position to a sensor that detects a timing for switching the energization state of the plurality of stator coils according to a rotational position of the plurality of magnetized units, from a magnetized region on at least one end surface. Also includes a detection region disposed inside.

  In this rotor, the detection area is arranged inside the magnetized area. For this reason, since the inside of the magnetized region can be effectively used as a space for arranging a plurality of detecting units in the detecting region, the detecting unit is arranged in the direction in which the radial dimension of the rotor increases, particularly outside the magnetizing region. There is no need to let them. Therefore, it is possible to provide a motor having a compact configuration in which the detection unit is arranged inside the magnetized region.

  It is desirable that the plurality of detection units be distributed along a plurality of concentric circles. Even if the number of detectors is increased, it can be distributed along a plurality of concentric circles in the space inside the magnetized region, so it is easy to provide a motor that can detect the rotational positions of the magnetized parts with higher accuracy. .

  Each of the plurality of detection units preferably includes a concave portion that is recessed with respect to at least one end surface or a convex portion that protrudes with respect to at least one end surface. Each of the plurality of sensors is typically a non-contact type proximity sensor, and easily detects a plurality of concave portions or protruding convex portions that are recessed with respect to the end face of the rotor. Typically, the magnetized region desirably includes a plurality of bar magnets that constitute a plurality of magnetized portions.

  One of the different aspects of the present invention is an in-wheel motor having the motor and a hub for transmitting the rotational force of the motor. One of the different aspects of the present invention is a vehicle having the in-wheel motor.

The top view which showed schematic structure of the vehicle carrying an in-wheel motor. Sectional drawing which showed the wheel from the II-II direction (II-II cross section of FIG. 1). The figure which showed schematic structure of the rotor from the III-III direction. The figure which showed schematic structure of the rotor and the stator from the IV-IV direction.

  FIG. 1 shows a schematic configuration of a vehicle 100 equipped with an in-wheel motor according to the present invention. The vehicle 100 includes a vehicle body 105 and a right front wheel (wheel) 101, a left front wheel 102, a right rear wheel 103, and a left rear wheel 104 supported on the vehicle body 105 via a suspension mechanism (not shown). Each of the wheels 101 to 104 includes an annular wheel 90 and a tire 91 attached to the wheel 90, and an in-wheel motor 80 is mounted inside the wheel 90. The vehicle body 105 includes a power storage device 106 such as a battery that supplies power to the in-wheel motor 80, and an inverter 107 that converts DC power supplied from the power storage device 106 into AC power.

  FIG. 2 is a cross-sectional view of the right front wheel (wheel) 101 seen from the II-II direction in FIG. Hereinafter, a specific configuration will be described with respect to the right front wheel 101. The right rear wheel 103 is the same as the configuration of the right front wheel 101, and the left front wheel 102 and the left rear wheel 104 are symmetrical to the right front wheel 101. is there. An in-wheel motor 80 is accommodated in the wheel 90 of the wheel 101. The in-wheel motor 80 includes an axial gap type motor (axial motor) main body 1 and a proximity sensor 30 that detects rotation of the motor main body 1. The wheel 90 includes a housing 71 that houses the motor body 1 and the proximity sensor 30, a support plate 72 that attaches the housing 71 to the vehicle body 105 via a suspension mechanism (not shown), a shaft 73 that passes through the housing 71, A hub 74 that transmits the rotational force (driving force, torque) of the in-wheel motor 80 to the wheel 90 is housed. The hub 74 is rotatably connected to the shaft 73 via a bearing 75. The wheel 90 further accommodates a brake disc 76 that brakes the rotation of the hub 74 and a brake caliper 77 that tightens the brake disc 76 and transmits a braking force to the wheel 90.

  The motor main body 1 includes a disk-shaped rotor 10 that rotates around an axis (shaft) 73 and a pair of stators 20 that are disposed on both sides of the rotor 10 in the axial direction 73a. The rotor 10 sandwiched between a pair of stators 20 includes a disk-shaped rotor yoke 11 rotatably connected to a shaft 73 via a hub 74 and a bearing 75, and end faces on both sides of the rotor yoke 11 in the axial direction 73a. The plurality of magnetized portions 12 magnetized so that magnetic poles appear along the peripheral edges 19 of 11a and 11b and the plurality of magnetized portions 12 on the end surface 11a of the rotor yoke 11 are closer to the shaft 73 (inner side). And a plurality of recesses 13 provided in.

  The plurality of magnetized portions 12 are configured by a plurality of bar magnets 52 embedded so as to penetrate the rotor yoke 11 in the axial direction 73a. Each of the plurality of bar magnets 52 has one end (N extreme, first magnetized portion) 12n in the axial direction 73a magnetized to the N pole (first pole) and the S pole (second pole). The other end (S extreme, second magnetized portion) 12s of the magnetized axial direction 73a is provided. The N extreme 12n and the S extreme 12s are embedded so as to slightly protrude from the end faces 11a and 11b on both sides of the rotor yoke 11, and the N extreme 12n and the S extreme 12s form different magnetized portions 12, respectively. An example of the bar magnet 52 is a rod-shaped rare earth magnet having the highest magnetic flux density among commercially available permanent magnets.

  One set of stators 20 arranged so as to sandwich the end faces 11a and 11b on both sides of the rotor 10 from the axial direction 73a includes a plurality of salient pole sets 25 arranged facing each other across the rotor yoke 11, and a plurality of stator pole sets 25 A plurality of stator coils 26 wound around each of the salient pole sets 25 are provided. Each of the plurality of salient pole sets 25 includes a first salient pole portion 21 facing the end surface 11 a of the rotor 10 and a second salient pole portion 22 facing the end surface 11 b of the rotor 10. The first salient pole portion 21 and the second salient pole portion 22 are fixed to the housing 71. Further, each of the plurality of stator coils 26 is wound around the first salient pole portion 21 and the second salient pole portion 22 constituting one salient pole set 25 so that the direction of the magnetic flux is the same. Yes. That is, the direction of current flow is controlled by the coil wound around the first salient pole portion 21 and the coil wound around the second salient pole portion 22 constituting the pair as one stator coil 26. It is like that.

  The rotor 10 has a magnetized region in which a plurality of magnetized portions 12 magnetized so that magnetic poles appear on the end faces 11a and 11b on both sides in the axial direction 73a are arranged along the peripheral edges 19 of the end faces 11a and 11b on both sides. 10a is included. The rotor 10 further includes a plurality of recesses 13 that provide a rotational position to the proximity sensor 30 that detects timing for switching the energized states of the plurality of stator coils 26 according to the rotational positions of the plurality of magnetized portions 12. This includes a detection region 10b arranged inside the magnetized region 10a. That is, the plurality of recesses 13 in this example function as detection units (marks, symbols) 13 that cause the proximity sensor 30 to detect the rotational positions of the plurality of magnetized units 12. The plurality of recesses 13 are arranged around the shaft 73 of the rotor yoke 11 and are formed so that one end surface 11a of the rotor yoke 11 is intermittently recessed.

  When a current is passed through the stator coil 26 arranged so as to face the magnetized region 10a, the direction of the magnetic flux of the first salient pole portion 21 and the second salient pole portion 22 constituting one salient pole set 25 is changed. Excitation is performed so that the magnetic poles of the first salient pole portion 21 and the second salient pole portion 22 are staggered to be the same. For example, when the first salient pole portion 21 constituting one salient pole set 25 is excited to the N pole, the opposing second salient pole portion 22 is excited to the S pole, and the first salient pole portion When 21 is excited to the S pole, the opposing second salient pole portion 22 is excited to the N pole. Furthermore, the direction of the magnetic pole in which the adjacent salient pole set 25 is excited is controlled in accordance with the rotational speed of the rotor 10. Therefore, the plurality of magnetized portions 12 of the rotor 10 obtain the magnetic force from the plurality of salient pole sets 25 and rotate the rotor 10.

  The proximity sensor 30 is disposed at a portion of the housing 71 facing the detection region 10b of the end surface 11a of the rotor 10. The proximity sensor 30 is disposed between the plurality of first salient pole portions 21 disposed on the vehicle body 105 side and the shaft 73. The proximity sensor 30 is a non-contact type sensor 30 provided so as to correspond to each of the plurality of salient pole sets 25 on a one-to-one basis. The current direction of the wound stator coil 26 is controlled, and the direction of the magnetic pole excited in the salient pole set 25 is controlled. The proximity sensor 30 is disposed so as to face the detection region 10b in which the plurality of recesses 13 of the rotor 10 are disposed, and when the rotor 10 rotates, one of the plurality of recesses 13 crosses the front of the proximity sensor 30. ing. An example of the proximity sensor 30 is an electromagnetic wave method, an ultrasonic wave method, an infrared ray method, or the like that measures the distance to the detection target.

  FIG. 3 shows a schematic configuration of the rotor 10 as seen from the III-III direction of FIG. The rotor 10 includes 18 magnetized portions 12 arranged in the magnetized region 10a and 18 concave portions 13 arranged in the detection region 10b inside the magnetized region 10a. Each of the 18 bar magnets 52 is disposed at equal intervals (equal angular intervals) at a pitch of about 20 degrees along the circumferential direction 110 centering on the shaft 73. Further, the adjacent magnetized portions 12 are press-fitted (arranged) into the rotor yoke 11 so that the magnetized portions 12 appearing on the end surface 11a of the rotor 10 are staggered between adjacent magnetic poles.

  Each of the eighteen recesses 13 has a fan-like shape when viewed from the front, and nine concentric circles of two sizes (two rows) centered on the shaft 73 of the end surface 11a are arranged at equal intervals (equal angular intervals). The recesses 13 are arranged at a pitch of about 40 degrees and are arranged in two large and small concentric circles, with the positions in the radial direction 112 being shifted. In other words, the 18 recesses 13 are arranged in a distributed manner along two concentric circles. The width (length, size) w of each concave portion 13 in the circumferential direction 110 is the circumferential direction 110 of the adjacent first magnetized portion (N extreme) 12n and second magnetized portion (S extreme) 12s. Are defined to be approximately equal to the adjacent angle θ.

  In this way, by disposing the respective concave portions 13 along two (a plurality of) concentric circles, the rotational position of the plurality of magnetized portions 12 can be stably and accurately detected by the proximity sensor 30. Can do. Therefore, it is possible to provide the motor main body 1 having a compact configuration in which the inside of the magnetized region 10a is effectively used as a space for arranging the plurality of detection units 13 in the detection region 10b. The plurality of recesses 13 can be distributed and arranged along three or more concentric circles, and the rotational positions of the plurality of magnetized portions 12 can be detected with higher accuracy by increasing the number of recesses 13. it can.

  FIG. 4 shows a positional relationship between the plurality of magnetized portions 12 of the rotor 10 and the plurality of first salient pole portions 21 of the stator 20 as viewed from the IV-IV direction in FIG. In addition, the positional relationship between the plurality of recesses 13 and the proximity sensor 30 is also shown. Each of the 14 first salient pole portions 21 of the stator 20 is disposed at equal intervals (equal angular intervals) at a pitch of about 26 degrees along the circumferential direction 110 centering on the shaft 73. . Each of the 14 proximity sensors 30 corresponds to each of the 14 first salient pole portions 21 on a one-to-one basis. In this example, the two proximity sensors 30 have two sizes (2 7) are arranged at equal intervals (equal angular intervals) with a pitch of about 51 degrees. For this reason, the proximity sensor 30 can be arrange | positioned in the position which opposes the detection area | region 10b inside the magnetized area | region 10a. Therefore, in the axial gap type motor body 1 in which the rotor 10 and the stator 20 face each other in the axial direction 73a, the space between the stator coil 26 and the shaft 73 can be effectively used as a space for arranging the proximity sensor 30.

  In the in-wheel motor 80 of this example, when the concave portion 13 approaches the proximity sensor 30 as the rotor 10 rotates, and the proximity sensor 30 detects the concave portion 13, the first salient pole portion 21 corresponding to the proximity sensor 30 is moved to the first salient pole portion 21. The energized state can be switched off so that no current flows through the wound stator coil 26. On the other hand, when the end surface 11a other than the recess 13 approaches the proximity sensor 30 as the rotor 10 rotates, and the proximity sensor 30 detects the end surface 11a, the rotor 10 is wound around the first salient pole portion 21 corresponding to the proximity sensor 30. The energized state can be switched on so that a current flows through the stator coil 26. For this reason, since each stator coil 26 is detected and controlled by the proximity sensor 30 unit, the control is redundant and the reliability is high.

  For example, when the first salient pole part 21 corresponding to the proximity sensor 30 that has detected the end face 11a is the N pole part 21n, the S extreme 12s of the bar magnet 52 embedded in the end face 11a is attracted to the N pole part 21n, Since the N extreme 12n of the bar magnet 52 repels from the N pole portion 21n, the rotor 10 rotates in the circumferential direction 110. Similarly, when the first salient pole portion 21 corresponding to the proximity sensor 30 that has detected the end surface 11a is the S pole portion 21s, the N extreme 12n of the bar magnet 52 embedded in the end surface 11a is attracted to the S pole portion 21s. Since the S extreme 12s of the bar magnet 52 repels from the S pole portion 21s, the rotor 10 rotates in the circumferential direction 110. As described above, the 18 recesses 13 in this example are the detection units (marks, symbols) 13 indicating that the rotational positions of the 18 bar magnets 52 are positions where the energization to the stator coil 26 is turned off. Function as. The shape of the detection unit 13 is not limited to the concave part, and may be a convex part, a hole part, a slit, or the like as long as it can be detected by the proximity sensor 30. Furthermore, the non-contact type proximity sensor 30 that measures the distance to the detection target is less susceptible to light and foreign matter (dust), and is therefore suitable as a detection mechanism in the in-wheel motor 80.

  As shown in FIGS. 3 and 4, the rotor 10 includes a magnetized region 10a including a plurality of magnetized portions 12 magnetized so that magnetic poles appear along the peripheral edge 19 of the end surface 11a, and a magnetized portion. The proximity sensor 30 corresponding to the salient pole set 25 detects the rotational position of the magnetized portion 12 in order to switch the energization state of the stator coil 26 wound around the salient pole set 25 corresponding to the 12 rotational positions. And a detection region 10b including a plurality of detection units (concave portions) 13 for the purpose.

  Further, in the rotor 10, the detection region 10b is disposed inside the magnetized region 10a. For this reason, since the inside of the magnetized region 10a can be effectively used as a space for arranging the plurality of detection units 13 in the detection region 10b, it is necessary to arrange the detection unit 13 in a direction in which the radial direction 112 of the rotor 10 increases. Absent. Therefore, it is possible to provide the motor body 1 having a compact configuration in which the detection unit 13 is disposed inside the magnetized region 10a. Furthermore, since the plurality of recesses 13 can be arranged inside the magnetized region 10a, the motor body 1 having a high torque can be easily obtained by increasing the radius of the rotor 10 and increasing the number of bar magnets 52 in the magnetized region 10a. Can provide.

  In the in-wheel motor 80 of this example, the position immediately before the second magnetized portion (S extreme) 12s overlaps the N pole portion 21n of the first salient pole portion 21 in the axial direction 73a, that is, the S extreme 12s is N. It is possible to prevent the current from flowing to the stator coil 26 wound around the N pole portion 21n from a position immediately before passing immediately below (directly above) the pole portion 21n. Therefore, it is possible to prevent the rotational force of the rotor 10 from being weakened by being attracted to the N pole portion 21n before the S extreme 12s passes just below (just above) the N pole portion 21n.

  Furthermore, the position immediately after the second magnetized portion (S extreme) 12s overlaps the next S pole portion 21s adjacent to the passed N pole portion 21n in the axial direction 73a, that is, the S extreme 12s is the S pole portion 21s. It is possible to prevent a current from flowing through the stator coil 26 wound around the S pole portion 21 s until a position immediately after passing just below (directly above). Therefore, it is possible to prevent the rotational force of the rotor 10 from being weakened by the repulsion from the S pole portion 21 s until the S extreme 12 s passes immediately below (above) the S pole portion 21 s. The same applies to the case where the first magnetized portion (N extreme) 12n passes directly below (directly above) the first salient pole portion 21.

  Thus, in the rotor 10 of this example, the concave portion (detection unit) 13 corresponds to the adjacent N extreme (first magnetized portion) 12n and S extreme (second magnetized portion) 12s. The recess 13 is formed so that the angle θ in the circumferential direction 110 between the N extreme 12n and the S extreme 12s is substantially equal. For this reason, the N extreme 12n and the S extreme 12s can reliably switch off the energization to the stator coil 26 at a position overlapping the N pole portion 21n and the S pole portion 21s in the axial direction 73a. Energization to the stator coil 26 can be reliably switched on at a position where the extreme 12s does not overlap the N pole portion 21n and the S pole portion 21s in the axial direction 73a. Accordingly, the size w in the circumferential direction 110 is defined so that the angle θ in the circumferential direction 110 between the detection unit 13 and the adjacent first and second magnetized portions 12n and 12s is substantially equal. With a simple configuration in which the concave portion 13 is disposed, it is possible to reliably perform on / off control of energization to the stator coil 26, and to provide the motor body 1 that can easily improve torque.

  The in-wheel motor 80 provided with the motor body 1 according to the present invention can be mounted not only on a four-wheel drive vehicle but also on various electrically driven vehicles such as a hybrid vehicle, an electric motorcycle, and an electric wheelchair.

1 Motor body (axial motor)
10 Rotor 20 Stator 30 Proximity sensor 80 In-wheel motor

Claims (6)

A disk-shaped rotor that rotates around an axis;
An axial gap type motor having a pair of stators disposed on both sides in the axial direction of the rotor,
The rotor includes a magnetized region in which a plurality of magnetized portions magnetized so that magnetic poles appear on both end faces in the axial direction are arranged along the peripheral edges of the both end faces,
The one set of stators includes a plurality of stator coils arranged to face the magnetized region;
The rotor further includes a plurality of detection units that provide the rotational position to a sensor that detects a timing for switching the energization state of the plurality of stator coils according to the rotational positions of the plurality of magnetized units. A motor including a detection area disposed inside the magnetized area of the motor. In claim 1,
The plurality of detection units are arranged in a distributed manner along a plurality of concentric circles. In claim 1 or 2,
Each of the plurality of detection units includes a concave portion recessed with respect to the at least one end surface or a convex portion protruding with respect to the at least one end surface. In any of claims 1 to 3,
The magnetized region includes a plurality of bar magnets constituting the plurality of magnetized portions. A motor according to any one of claims 1 to 4,
An in-wheel motor having a hub for transmitting the rotational force of the motor.   A vehicle comprising the in-wheel motor according to claim 5.

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