JP2015159669A - shift switching motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shift switching motor capable of improving a maximum output value of the motor.SOLUTION: The shift switching motor is a motor that becomes a power source of a drive mechanism for switching a shift position of a shift switching unit. The motor includes: a rotor that rotates with a rotation axis; and a stator core 36 that is disposed coaxially with the rotor and includes a plurality of teeth. The stator has magnetic resistance different for right and left regions of a center of a tooth 40 for winding around which a coil is wound.

Description

  Embodiments described herein relate generally to a shift switching motor.

  Motors as power sources are used in various fields. Motors have been developed with various performances according to the usage and usage environment, and the performance and maintainability have been improved.

Japanese Patent No. 4726526 JP 2009-118611 A

  By the way, in recent years, in the field of automobiles, the adoption of shift-by-wire, in which a transmission and a shift lever are electrically connected and the transmission is switched according to the state of the shift lever, is increasing. In the case of shift-by-wire, since the gears and the like are switched by the motor based on a signal indicating the operation state of the shift lever, it is important to develop a small and high-output motor. In general, the motor has a relationship that the torque is low in the high rotation range and the rotation speed is low in the high torque range. The output of the motor can be expressed by the number of revolutions × torque × constant. In the middle torque region (medium rotation region) where the maximum output is obtained, the magnetic path resulting from the positional relationship between the shape of the stator core and the magnet on the rotor side is used. There is a problem that the maximum output value is likely to be affected by the inductance component due to the change (switching of the magnetic circuit).

  The present invention has been made in view of the above, and an object of the present invention is to provide a shift switching motor capable of improving the maximum output value of the motor.

  The shift switching motor according to the embodiment is a motor that is a power source of a drive mechanism that switches the shift position of the shift switching device, and the motor is disposed with a rotor that rotates together with a rotating shaft, and the rotor. A stator having a plurality of teeth, and the stator has a different magnetic resistance with respect to left and right regions around the teeth around which the coil is wound. According to this aspect, as an example, it can be suppressed that the magnetic field passing through the tooth around which the coil is wound is divided substantially equally on the left and right of the tooth. As a result, an increase in inductance component due to switching of the magnetic field during one energization can be suppressed, and the maximum output value of the motor can be improved (improved).

  Further, the stator of the shift switching motor according to the embodiment may be configured such that the magnetic path is formed with respect to the left and right regions asymmetrically around the teeth around which the coil is wound. According to this aspect, as an example, it is possible to suppress the magnetic field passing through the tooth around which the coil is wound from being divided substantially evenly on the left and right sides of the tooth by making the magnetic path formation asymmetrical. As a result, an increase in inductance component due to switching of the magnetic field during one energization can be suppressed, and the maximum output value of the motor can be improved (improved).

  In the shift switching motor according to the embodiment, the magnetic path of the stator may be formed such that the yoke that forms one magnetic path is narrower than the yoke that forms the other magnetic path. According to this aspect, as an example, one of the yoke shapes of the stator is narrowed so that the magnetic field does not easily pass through the narrow yoke among the magnetic fields passing through the teeth around which the coil is wound. Can be. As a result, an increase in inductance component due to switching of the magnetic field during one energization can be suppressed, and the maximum output value of the motor can be improved (improved).

  Further, the yoke on the narrow side connected to the tooth around which the coil of the shift switching motor according to the embodiment is connected is connected to the base side of the tooth around which the coil is wound, and the other end May be connected via a non-linear connecting portion to a position deviated to the base side by a predetermined distance from the tip of the tooth adjacent to the tooth around which the coil is wound. According to this aspect, as an example, a space formed around the connection position of the narrow yoke can be used as an arrangement space for other components, for example. That is, it is possible to effectively use the space around the motor while improving (improving) the maximum output value of the motor. As a result, the motor performance can be improved and the motor can be miniaturized.

  Moreover, as for the formation aspect of the magnetic path of the stator of the shift switching motor according to the embodiment, one may be disconnected and the other may be connected by a yoke. According to this aspect, as an example, one of the teeth around which the coil is wound is disconnected from the yoke so that the magnetic field passing through the teeth around which the coil is wound passes through one yoke. it can. As a result, an increase in inductance component due to switching of the magnetic field during one energization can be suppressed, and the maximum output value of the motor can be improved (improved).

  Further, the stator of the shift switching motor according to the embodiment has a through hole for component insertion in a yoke connected to the teeth, and the through hole is parallel to the rotation shaft and It may be formed inside the outer shape of the coil in the radial direction. According to this aspect, as an example, support of components related to the motor can be realized in a space-saving manner. For example, it is possible to dispose a support shaft for a gear that meshes with the gear of the rotation shaft of the motor, and it is possible to reduce the distance between the shafts, thereby contributing to the miniaturization of the motor unit including the motor. In addition, for example, it is possible to dispose a support component that supports a substrate that controls the motor, which can contribute to miniaturization of the motor unit including the motor.

FIG. 1 is a schematic cross-sectional view of a motor unit including a shift switching motor according to an embodiment. FIG. 2 is a plan view showing the shape of the stator of the shift switching motor according to the embodiment. FIG. 3 is an exploded perspective view of a motor unit to which the shift switching motor according to the embodiment can be applied. FIG. 4 is a diagram illustrating a meshing relationship when a motor unit to which the shift switching motor according to the embodiment is applicable is viewed from the axial direction. FIG. 5 is a perspective view showing a main part of a parking lock device to which the shift switching motor according to the embodiment can be applied. FIG. 6 is a plan view showing an example of the shape of a stator core of a conventional motor. FIG. 7 is a characteristic diagram showing an example of the TN characteristic (torque versus rotational speed) of the shift switching motor according to the embodiment and the conventional motor. FIG. 8 is a plan view showing a first modification of the shape of the stator core of the shift switching motor according to the embodiment. FIG. 9 is a plan view showing a second modification of the shape of the stator core of the shift switching motor according to the embodiment. FIG. 10 is a plan view showing a third modification of the shape of the stator core of the shift switching motor according to the embodiment.

  Hereinafter, exemplary embodiments of the present invention are disclosed. The configuration of the embodiment shown below, and the operation and result (effect) brought about by the configuration are merely examples. The present invention can be realized by configurations other than those disclosed in the following embodiments, and various effects (including derivative effects) obtained by the basic configuration can be obtained.

  FIG. 1 is a cross-sectional view of a motor unit 12 including a shift switching motor 10 according to the present embodiment. FIG. 1 shows a configuration including an inner rotor type shift switching motor 10. The motor unit 12 is covered with a housing case 14 adjacent to a shift switching device (transmission device) (not shown). The housing case 14 includes a first case 16 having a substantially cylindrical shape with a bottom and a second case 18 having a substantially cylindrical shape with a lid, and the first case 16 and the second case 18 have openings facing each other. Are fitted to form a housing space for the shift switching motor 10.

  The first case 16 is formed with a substantially cylindrical support portion 16 a that protrudes in a direction away from the second case 18. A substantially cylindrical bush 20 is fitted to the support portion 16a. An output shaft 22 that is rotated by the shift switching motor 10 is supported by the bush 20. A distal end side of the output shaft 22 protruding from the support portion 16a forms a substantially cylindrical connecting portion 22a having a reduced diameter. The output shaft 22 is fixed to a positioning plate of a shift switching device, which will be described later, via a connecting portion 22a. Accordingly, the output shaft 22 is integrated with the positioning plate and rotates about the axis Ax. The output shaft 22 is formed with a substantially circular support recess 22 b on the inner side of the first case 16.

  The housing case 14 houses and holds a shift switching motor 10 that is an induction pole type brushless motor that functions as a power source of a drive mechanism (parking lock device) that switches the shift position of the shift switching device. The second case 18 is provided with a substantially cylindrical covered concave portion 18a concentric with the support portion 16a. The second case 18 has a plurality of (six in this embodiment) bottomed substantially cylindrical mounting recesses 18b at the same distance in the radial direction across the axis Ax. Similarly, a plurality of (six in this embodiment) bottomed substantially cylindrical mounting recesses 16b are formed in the first case 16 at the same distance in the radial direction across the axis Ax. And each attachment recessed part 16b, 18b is arrange | positioned so that opening parts may mutually oppose. In the housing case 14, support shafts 24 and 26 having both ends fixed to the opposing mounting recesses 16 b and 18 b are accommodated. The support shafts 24 and 26 have axis lines Ax1 and Ax2 parallel to the axis line Ax, respectively. Although the support shafts 24 and 26 are shown in FIG. 1, similar support shafts can be fixed to the mounting recesses 16b and 18b facing each other.

  The shift switching motor 10 includes a stator 32 and a rotor 34 between a holder 28 and a control board 30 that form the outer shape thereof.

  The holder 28 is accommodated on the first case 16 side in the housing case 14, has a substantially flat lid wall portion 28 a that extends in a direction orthogonal to the axis Ax, and is concentric with the axis Ax. A substantially cylindrical shaft insertion portion 28b protruding from the side 28a toward the second case 18 is provided. The holder 28 is positioned in the housing case 14 with the support shafts 24 and 26 penetrating the lid wall portion 28a and the peripheral edge portion of the lid wall portion 28a abutting against a flange portion formed on the inner wall of the first case 16. Has been.

  The control board 30 is accommodated on the second case 18 side in the housing case 14 and is formed in a substantially flat plate shape extending in a direction orthogonal to the axis Ax. The control board 30 is formed with a substantially circular shaft insertion hole 30a concentric with the axis Ax. Support shafts 24 and 26 are passed through the control board 30.

  The stator 32 includes a stator core 36 and a plurality (six in this embodiment) of coils 38. As an example, the stator core 36 has a substantially cylindrical shape concentric with the axis Ax as shown in the plan view of FIG. 2, in which a plurality of thin electromagnetic steel plates are laminated and integrated by a joining means such as welding. The stator core 36 has a plurality of teeth protruding on the inner peripheral side. In the present embodiment, as an example, six teeth around which the coil 38 (see FIG. 1) is wound and six teeth around which the coil 38 is not wound are alternately arranged. Hereinafter, the tooth around which the coil 38 is wound is referred to as a winding tooth 40. On the other hand, the teeth around which the coil 38 is not wound are referred to as non-winding teeth 42. A wide main yoke (yoke) 44 is formed on one side of the outer peripheral side (base side) of the winding tooth 40 and is connected to the adjacent non-winding tooth 42. Further, a narrow (narrow) auxiliary yoke (yoke) 46 is formed on the other side of the outer peripheral side (base side) of the winding tooth 40 and is connected to the adjacent non-winding tooth 42.

  As shown in FIG. 2, one end of the auxiliary yoke 46 is connected to the base side of the winding tooth 40 (the outer peripheral side of the stator core 36). On the other hand, the other end of the auxiliary yoke 46 is an insertion hole 46a, which is a through hole for component insertion, at a position that is biased to the base side by a predetermined distance from the tip of the non-winding tooth 42 adjacent to the winding tooth 40. Connected through. The insertion hole portion 46a is formed of a non-linear thin member (a connection portion 130 described later) and has a function of connecting the auxiliary yoke 46 and the non-winding tooth 42. The insertion hole 46b of the insertion hole 46a is formed to be parallel to the axis Ax so as to allow the insertion of the support shafts 24 and 26 described above.

  Returning to FIG. 1, the stator core 36 is located on the outer peripheral side of the shaft insertion portion 28b, is sandwiched between the holder 28 and the control board 30, and the support shafts 24 and 26 are press-fitted into the insertion hole portion 46a. The housing case 14 is positioned in contact with the wall 28a.

  In this embodiment, in response to the fact that the shift switching motor 10 is an induction pole type, a plurality (12) of teeth, that is, six winding teeth 40 and six non-winding teeth 42 are provided. They are arranged alternately. The characteristics based on the shape of the stator core 36 will be described later.

  The rotor 34 includes a rotating shaft 48, a rotor core 50, and a magnet 52. The rotating shaft 48 is arranged coaxially with the axis Ax. The rotating shaft 48 includes substantially cylindrical support portions 48a and 48b formed at both ends, a substantially cylindrical insertion portion 48c having a diameter larger than that of the support portion 48b, and a diameter further increased than that of the insertion portion 48c. The substantially cylindrical fixed portion 48d and the first helical gear portion 48e connected to the fixed portion 48d are integrally formed. The support portion 48a is disposed on the inner peripheral side of the support recess 22b of the output shaft 22, and is supported by the output shaft 22 by a bearing 54 interposed between the support recess 48b. The support portion 48b is disposed on the inner peripheral side of the support recess 18a of the second case 18, and is supported on the second case 18 by a bearing 56 interposed between the support recess 48a. Thereby, the rotating shaft 48 can be rotated around the axis Ax.

  The insertion part 48c is disposed adjacent to the support part 48b and penetrates the control board 30 in a rotatable manner. The fixed portion 48 d is disposed adjacent to the insertion portion 48 c, and the distal end portion thereof is disposed on the inner peripheral side of the shaft insertion portion 28 b of the holder 28. The first helical gear portion 48e is disposed on the inner peripheral side of the shaft insertion portion 28b and between the support portion 48a and the fixed portion 48d. The diameter of the tip circle of the first helical gear portion 48e is set to be equal to or smaller than the diameter of the fixed portion 48d, that is, the maximum diameter of the rotating shaft 48. The first helical gear 48e is a so-called small number helical gear having a small number of teeth and a large helix angle so that the gear diameter is sufficiently small.

  The rotor core 50 includes a substantially disc-shaped connecting portion 50a that is fixed in a state where the fixing portion 48d of the rotating shaft 48 passes through between the shaft insertion portion 28b of the holder 28 and the control board 30, and an outer peripheral portion of the connecting portion 50a. A substantially cylindrical main body 50b protruding in a direction approaching the holder 28 is integrated and configured. The main body 50b is disposed between the shaft insertion portion 28b of the holder 28 and the stator core 36 concentrically with the axis Ax, and is rotatably supported via a substantially cylindrical bush 58 fitted to the shaft insertion portion 28b. Has been. The magnet 52 is fixed to the outer peripheral surface of the main body 50b on the inner peripheral side of the stator core 36, and is formed in a substantially cylindrical shape so that the polarities of the magnetic poles (N pole and S pole) are switched at equal angular intervals. The magnet 52 can be formed in a ring shape, for example, and by performing sinusoidal magnetization, cogging and torque ripple can be suppressed even when the stator core 36 has a characteristic shape as described above.

  Thus, the shift switching motor 10 is accommodated and held in the housing case 14. When power is supplied to the shift switching motor 10, the rotor 34 (magnet 52) that interacts with the rotating magnetic field formed by the stator 32 rotates around the axis Ax.

  Note that the intermediate gear 60 is rotatably supported on the support shaft 24 while being sandwiched between the lid wall portion 28 a of the holder 28 and the first case 16. The intermediate gear 60 protrudes toward the first case 16 from the second helical gear portion 60a and the substantially helical disk-shaped second helical gear portion 60a sandwiched between the lid wall portion 28a and the output shaft 22. A spur gear-like drive gear portion 60b that is in contact with the peripheral edge portion on the opening end side is integrally formed. In the intermediate gear 60, the second helical gear portion 60 a meshes with the first helical gear portion 48 e of the rotating shaft 48. Therefore, when the rotating shaft 48 rotates, the intermediate gear 60 rotates in conjunction with this. At this time, the rotation of the rotating shaft 48 is decelerated according to the gear ratio of the first helical gear portion 48e and the second helical gear portion 60a and transmitted to the intermediate gear 60. Note that, at a position in the axial direction, the drive gear portion 60 b of the intermediate gear 60 overlaps with a portion protruding into the housing case 14 of the output shaft 22.

  FIG. 3 is an exploded perspective view of a motor unit 12 (a part of the shift device) to which the shift switching motor 10 can be applied. Specifically, a perspective view of a first helical gear portion 48e that is operated by a rotor (rotor 34) rotated by a rotating magnetic field generated by the stator 32 of the shift switching motor 10 is shown. Then, the relationship between the second helical gear portion 60a (the intermediate gear 60 fixed to the support shaft 24) meshing with the first helical gear portion 48e, the driven lever 62 rotated by the intermediate gear 60, and the output shaft 22 is a perspective view. It is shown in As shown in FIG. 3, the protruding portion corresponding to the support recess 22 b of the output shaft 22 is fixed in a state of penetrating the driven lever 62. The follower lever 62 has a structure in which a substantially sector-shaped small-diameter portion 62a centering on the axis Ax and a substantially sector-shaped large-diameter portion 62b having a larger diameter than the small-diameter portion 62a are integrated. The small diameter part 62a and the large diameter part 62b are connected to each other so as to be continuous in the circumferential direction around the axis Ax. The large-diameter portion 62b is formed with a substantially arc-shaped insertion hole 62c centered on the axis Ax.

  FIG. 4 is a diagram showing a meshing relationship when the motor unit 12 to which the shift switching motor 10 can be applied is viewed from the axial direction. As shown in FIG. 4, the opening width in the radial direction around the axis Ax of the insertion hole 62c of the driven lever 62 is set to be larger than the diameter of the drive gear portion 60b. A fan-shaped internal gear 64 that meshes with the drive gear portion 60b inserted into the insertion hole 62c is formed on the wall surface. Therefore, when the intermediate gear 60 (drive gear portion 60b) rotates, the internal gear 64 (driven lever 62) rotates together with the output shaft 22 in conjunction with the rotation. At this time, the rotation of the intermediate gear 60 is decelerated according to the gear ratio between the drive gear portion 60b and the internal gear 64 and transmitted to the driven lever 62 and the like.

  As described above, the motor unit 12 including the shift switching motor 10 according to the present embodiment includes the gear ratio of the first helical gear portion 48e and the second helical gear portion 60a serving as the first reduction gear stage, and the drive gear portion 60b serving as the second reduction gear stage. And the speed is reduced by the gear ratio of the internal gear 64. The motor unit 12 is reduced in size by combining the rotary shaft 48 and the output shaft 22 so as to be coaxial with each other.

  FIG. 5 is a perspective view showing the main part of the parking lock device 100 to which the shift switching motor 10 (motor unit 12) can be applied as described above. As shown in FIG. 5, the parking lock device 100 included in the shift switching device has a parking gear 102 and a lock pawl 104 that engages and disengages with the parking gear 102. The parking gear 102 and the lock pole 104 are provided in a housing case (not shown) of a transmission provided in the vehicle. The parking gear 102 is fixed to a crankshaft (not shown) of an engine that is inserted into a housing case of the transmission, and rotates together with the crankshaft. The parking gear 102 is restricted from rotating when the engaging claw 104a of the lock pole 104 is engaged with the teeth 102a. The lock pole 104 is disposed adjacent to the parking gear 102 and is swingably supported by an intermediate plate (not shown) fixed in the housing case of the transmission. The lock pole 104 is supported so that the base end portion thereof can rotate with respect to a support shaft 106 provided on the intermediate plate, and can rotate about the center axis C1 of the support shaft 106 as a rotation center.

  A locking claw 104 a is formed at the intermediate portion of the lock pole 104 on the side facing the parking gear 102. The lock pawl 104 rotates in a direction approaching the teeth 102a of the parking gear 102, and is guided to a position where the locking claw 104a meshes with the teeth 102a of the parking gear 102 (hereinafter referred to as a lock position). The lock pawl 104 prevents the parking gear 102 from rotating when the locking claw 104a is guided to the lock position.

  On the other hand, the lock pawl 104 rotates in a direction away from the teeth 102a of the parking gear 102, and the locking pawl 104a as shown in FIG. Hereinafter, it is guided to the unlock position. The lock pawl 104 is configured to allow the parking gear 102 to rotate by guiding the locking claw 104a to the unlock position.

  The positioning plate 108 that functions as a switching mechanism for the lock pole 104 has a connecting arm 108a extending from its base end. A park rod 110 is rotatably connected to the connecting arm 108a. The park rod 110 has a rod portion 110a formed by bending the base end portion into a substantially L shape and further bending the bent end portion into an L shape. The rod portion 110 a is formed to extend to the back surface position of the locking claw 104 a of the lock pole 104. The park rod 110 reciprocates in the direction in which the rod portion 110 a intersects the lock pole 104 as the positioning plate 108 reciprocates.

  A coil spring 112 is inserted through the rod portion 110 a of the park rod 110. The coil spring 112 has a base end portion engaged with a stopper piece 110b formed on the rod portion 110a, and a distal end portion engaged with a control cam 114 slidably inserted into the rod portion 110a. The control cam 114 is always urged by the coil spring 112 toward the distal end side of the rod portion 110a. The control cam 114 is configured such that its tapered cone-shaped cam surface 114 a is in sliding contact with the back surface of the locking claw 104 a of the lock pole 104. Accordingly, when the rod portion 110a of the park rod 110 reciprocates as the positioning plate 108 reciprocates, the control cam 114 reciprocates (slids) while contacting the back surface of the locking pawl 104a of the lock pole 104. As a result, based on the sliding of the control cam 114, the lock pawl 104 rotates around the central axis C1 of the support shaft 106 as a rotation center. That is, the lock pole 104 is rotated between the locked position and the unlocked position by the rotation of the positioning plate 108.

  When the lock pole 104 is in the unlock position shown in FIG. 5 and the positioning plate 108 rotates counterclockwise, the park rod 110 and the control cam 114 move to the lock pole 104 side. As the control cam 114 moves, the lock pole 104 rotates to the parking gear 102 side. As a result, the lock pole 104 is guided from the unlock position to the lock position.

  On the other hand, when the positioning plate 108 rotates in the clockwise direction from the state where the lock pole 104 is in the locked position, the park rod 110 and the control cam 114 are moved backward in a direction away from the lock pole 104. As the control cam 114 moves backward, the lock pawl 104 rotates away from the parking gear 102. As a result, the lock pole 104 is guided from the locked position to the unlocked position.

  In the present embodiment, the lock pole 104 is elastically applied in an anticlockwise direction in FIG. 5 by an elastic member (not shown), and is always in elastic contact with the control cam 114. The positioning plate 108 has a pair of lock holding recesses 116 and an unlock holding recess 118 formed on an arcuate circumferential surface 108b. The lock holding recess 116 is formed on one side (the clockwise direction in FIG. 5) of the peripheral surface 108b of the positioning plate 108. On the other hand, the unlock holding recess 118 is formed on the other side (counterclockwise direction side in FIG. 1) of the peripheral surface 108b of the positioning plate 108. The shape of the peripheral surface 108b between the lock holding concave portion 116 and the unlock holding concave portion 118 is a mountain shape, and is an asymmetric mountain shape whose highest apex is biased toward the lock holding concave portion 116 side. More specifically, the peripheral surface 108b on the lock holding recess 116 side is formed as a steep slope from the most apex, and the peripheral surface 108b on the unlock holding recess 118 side is formed as a gentle slope.

  A roller 120 a provided at the tip of the positioning spring 120 is in elastic contact with the peripheral surface 108 b of the positioning plate 108. The positioning spring 120 is constituted by, for example, a leaf spring, and its base end is fixed to an intermediate plate (not shown), and always presses the roller 120a provided at the distal end against the peripheral surface 108b of the positioning plate 108.

  When the positioning plate 108 is in the first rotation position (hereinafter also referred to as “unlock rotation position”) shown in FIG. 5 corresponding to the unlock position of the lock pole 104, the positioning spring 120 is moved by the roller 120a. The positioning plate 108 is biased and held at the rotation position by fitting into the unlock holding recess 118. On the other hand, when the positioning plate 108 is in the second rotation position corresponding to the lock position of the lock pole 104 (hereinafter also referred to as “lock rotation position”), the positioning spring 120 has the roller 120 a fitted in the lock holding recess 116. By combining, the positioning plate 108 is urged and held at the rotational position. More specifically, when the positioning plate 108 is rotated counterclockwise from the unlocked rotation position shown in FIG. 5 (first state), the roller 120a of the positioning spring 120 is disengaged from the unlock holding recess 118. It slides on the peripheral surface 108b toward the lock holding recess 116. When the roller 120a reaches the lock holding recess 116 from the unlock holding recess 118 beyond the top of the peripheral surface 108b, the roller 120a pressed against the peripheral surface 108b is fitted into the lock holding recess 116. ing. At this time, the positioning plate 108 is urged and held at the lock rotation position by the positioning spring 120.

  On the other hand, when the positioning plate 108 is rotated clockwise from the lock rotation position (second state), the roller 120a of the positioning spring 120 is detached from the lock holding recess 116 toward the unlock holding recess 118. It slides on the peripheral surface 108b. When the roller 120a reaches the unlock holding recess 118 from the lock holding recess 116 beyond the top of the peripheral surface 108b, the roller 120a pressed against the peripheral surface 108b is fitted into the unlock holding recess 118. It has become. At this time, the positioning plate 108 is urged and held at the unlocked rotation position by the positioning spring 120.

  As described above, the rotation range of the positioning plate 108 that rotates integrally with the output shaft 22 is limited between the unlock rotation position and the lock rotation position. Therefore, the formation range of the fan-shaped internal gear 64 (see FIG. 4) is set so as to include at least the meshing range with the drive gear portion 60b corresponding to the rotation range of the positioning plate 108. In other words, since the rotation range of the positioning plate 108 is limited, the required rotation transmission is satisfied by the sector-shaped internal gear 64.

  When the rotation shaft 48 is rotated by driving the shift switching motor 10, the rotation is decelerated between the first helical gear portion 48 e and the second helical gear portion 60 a and transmitted to the intermediate gear 60. When the intermediate gear 60 rotates, the rotation is further decelerated between the drive gear portion 60 b and the internal gear 64 and transmitted to the driven lever 62. As the driven lever 62 rotates, the output shaft 22 rotates together with the positioning plate 108. Thereby, the positioning plate 108 rotates in one direction toward the unlock rotation position, or rotates in the other direction toward the lock rotation position.

  Here, the shape of the stator core 240 for the conventional inner rotor is shown in FIG. 6 as a comparative example. In the case of the stator core 240, when the winding teeth 242 are the center, the magnetic path formation mode for the left and right regions is symmetrical. In the case of the stator core 240 as well, like the stator core 36 shown in FIG. 2, six winding teeth 242 and six non-winding teeth 244 are alternately arranged. When a coil is wound around each winding tooth 242 and a current flows through the coil, the magnetic path formation mode (the state of magnetic resistance) is substantially the same on the left and right sides of the winding tooth 242. As a result, the magnetic field passing through the winding teeth 242 is formed in the same manner as the left and right non-winding teeth 244 of the winding teeth 242 (the same magnetic fields P1, P2 are formed). ). In the induction pole motor configured to include the stator core 240, the left and right magnetic circuits are switched depending on the position of the magnet of the rotor during one energization. At that time, a delay occurs, which appears as an inductance component. The inductance component depends on the current value and the rotational speed. Therefore, the higher the rotation speed, the higher the current value, and the greater the torque depending on the current value, the more affected by the inductance component.

  Since the output value of the motor can be expressed by the number of revolutions x torque x constant, in the middle torque region (medium rotation region) where the maximum output is obtained, as described above, the shape of the stator core and the positional relationship of the magnet on the rotor side There is a tendency that the maximum output value is likely to be affected by an inductance component due to a change in magnetic path (switching of a magnetic circuit) due to this. FIG. 7 is an example of a TN characteristic indicating the relationship between the motor torque T and the rotational speed N. In FIG. A TN characteristic corresponding to a motor using the stator core 240 is indicated by a curve P. As described above, under the influence of the inductance component, the characteristic becomes a concave bow in the middle region (medium rotation region, medium torque region), and the output (maximum output) indicated by the number of revolutions x torque x constant decreases. It has been shown that.

  On the other hand, in this embodiment, the stator core 36 has a characteristic shape as shown in FIG. That is, when the stator core 36 is centered on the winding tooth 40, the magnetic resistance for the left and right regions is different. In other words, when the winding tooth 40 is the center, the magnetic path formation mode for the left and right regions is asymmetric. Specifically, the formation mode of the magnetic path passing through the winding tooth 40 is different between the right and left of the winding tooth 40. For example, the yoke (auxiliary yoke 46) that forms one magnetic path is narrower than the yoke (main yoke 44) that forms the other magnetic path. As described above, when the winding tooth 40 is the center, the magnetic field passing through the winding tooth 40 is substantially changed to the left and right of the winding tooth 40 by making the left and right magnetic path formation modes different. Dividing evenly can be suppressed. In other words, when the winding tooth 40 is the center, the magnetic resistance of one of the adjacent left and right regions is increased, or the magnetic path is narrowed (thinned) to make it difficult for the magnetic field to pass.

  In the case of the example of FIG. 2, one end of the narrow side yoke (auxiliary yoke 46) connected to the tooth (winding tooth 40) around which the coil 38 is wound is the base side (stator core) of the winding tooth 40. 36 outer peripheral side). Further, the position where the other end of the auxiliary yoke 46 is biased to the base side (outer peripheral side) by a predetermined distance from the tip (inner peripheral side of the stator core 36) of the tooth adjacent to the winding tooth 40 (non-winding tooth 42). It is connected to the. The other end of the auxiliary yoke 46 is connected via a non-linear connecting portion 130. The connection portion 130 forms an insertion hole portion (through hole) 46a for component insertion, and the support shafts 24 and 26 shown in FIG. The insertion hole 46 a is parallel to the output shaft 22 and is formed inside the outer shape of the coil 38.

  By adopting the stator core 36 as shown in FIG. 2 for the stator 32 of the shift switching motor 10, the following characteristics can be obtained. Specifically, the main yoke 44 that connects the winding tooth 40 and one non-winding tooth 42 of the two non-winding teeth 42 adjacent to the winding tooth 40 has been conventionally used. It is composed of a sufficiently wide street. That is, it is configured to ensure a sufficient magnetic path. On the other hand, the auxiliary yoke 46 connecting the winding tooth 40 and the other non-winding tooth 42 is sufficiently narrow (in a narrow shape) compared to the main yoke 44, and functions as a magnetic path. It is configured to reduce. That is, the magnetic field passing through the winding teeth 40 mainly passes through the magnetic path formed including the non-winding teeth 42 connected by the main yoke 44 (magnetic field Q1 in FIG. 2). On the other hand, only a small amount of the magnetic field can pass through the magnetic path formed including the non-winding teeth 42 connected by the auxiliary yoke 46. As a result, even if the left and right magnetic circuits are switched by the position of the magnet 52 of the rotor 34 during one energization, the magnetic field passes through the magnetic path formed including the non-winding teeth 42 connected by the auxiliary yoke 46. It is difficult to suppress the appearance of an inductance component.

  In FIG. 7, an example of a TN characteristic indicating a relationship between the torque T and the rotation speed N corresponding to the shift switching motor 10 using the stator core 36 is indicated by a curve Q. As described above, one of the yokes connected to the winding teeth 40 is made narrow so that the magnetic field does not easily pass therethrough, thereby suppressing the generation of an inductance component, so that the curve P when the stator core 240 is used The curve Q can be obtained by improving the concave bow shape. In particular, the characteristics of the intermediate region (medium rotation region, medium torque region) can be made closer to a straight line. As a result, the output (maximum output) represented by the number of revolutions x torque x constant can be improved. For example, when the current value is determined so as to generate the torque T1, the rotational speed of the motor to which the stator core 240 is applied is N1, whereas the rotational speed of the shift switching motor 10 to which the stator core 36 is applied is increased to N2. To do. That is, the speed of the shift switching operation of the shift switching device can be improved. In the case of shift-by-wire, it is desired to reduce the time lag until the shift switching is actually executed (completed) with respect to the user operation (shift operation). In the case of the shift switching motor 10 to which the stator core 36 of the present embodiment is applied, the rotation speed can be improved without causing a decrease in torque, so that the time lag at the time of the shift switching operation can be shortened. It is possible to improve the sense of incongruity caused by the time lag to be given or to prevent the time lag from being felt. Since the torque does not decrease even when the rotational speed is improved, even when the teeth 102a and the locking claws 104a are firmly meshed at the locked position (for example, in the case of slope parking), the transition to the unlocked position smoothly. Can do.

  As shown in FIG. 2, in the present embodiment, the connection portion 130 at the position where the insertion hole 46a is formed is configured in a non-linear shape. The magnetic field is less likely to pass if the magnetic path is non-linear than the linear shape. That is, by providing a non-linear portion in a part of the auxiliary yoke 46, the magnetic field is more difficult to pass, and the effect of suppressing the generation of inductance components can be improved. Moreover, the connection part 130 which forms the penetration hole part 46a is connected to the position biased to the base side (outer peripheral side) by a predetermined distance from the tip of the non-winding tooth 42. This is to prevent a new magnetic path from being formed if the rotor 34 disposed on the inner peripheral side of the stator core 36 and the connecting portion 130 are too close to each other. Further, the insertion hole 46 a is formed inside the outer shape of the coil 38 wound around the winding tooth 40. With such a configuration, it is possible to reduce the inter-axis distance between the axis Ax and another component assembled to the shift switching motor 10 using the insertion hole 46a. For example, the support shaft 24 inserted into the insertion hole 46 a serves as a support shaft for the intermediate gear 60. By making the formation position of the insertion hole 46a close to the axis Ax (the insertion hole 46a is set inside the outer shape of the coil 38), the diameter of the intermediate gear 60 can be reduced, and the motor unit 12 can be reduced in size. Can contribute. Similarly, when supporting other components, for example, a control board, a sensor, a capacitor, and the like for the shift switching motor 10 by the support shaft 26 inserted into the insertion hole 46a, the arrangement position is brought close to the axis Ax. Therefore, the motor unit 12 can be reduced in size. Further, the space Y formed by biasing the insertion hole 46a toward the axis Ax side can be used as a housing space for other components, which can contribute to an improvement in utilization efficiency of the space around the stator core 36.

  FIG. 8 is a plan view of a stator core 36 a that is a first modification of the stator core 36. The basic configuration is the same as that of the stator core 36 shown in FIG. 2, and the effect based on the shape of the stator core 36 a (the shape of the main yoke 44 and the auxiliary yoke 46) is the same as that of the stator core 36. However, the insertion hole 46a is omitted from the stator core 36a. That is, one end of the narrow side yoke (auxiliary yoke 46) connected to the teeth around which the coil 38 is wound (winding teeth 40) is the base side of the winding teeth 40 (the outer peripheral side of the stator core 36a). It is connected to the. Further, the position where the other end of the auxiliary yoke 46 is biased to the base side (outer peripheral side) by a predetermined distance from the tip (inner peripheral side of the stator core 36a) of the tooth (non-winding tooth 42) adjacent to the winding tooth 40. Thus, they are connected via a non-linear connecting portion 130. According to this configuration, the shape of the stator core 36a is simplified, which can contribute to a reduction in manufacturing cost. Further, the space Ya around the stator core 36a is enlarged, and the effective utilization of the space such as the arrangement of other parts is improved.

  FIG. 9 is a plan view of a stator core 36 b that is a second modification of the stator core 36. The basic configuration is the same as that of the stator core 36a shown in FIG. 8, and the effect based on the shape of the stator core 36b (the shapes of the main yoke 44 and the auxiliary yoke 46) is the same as that of the stator core 36a. However, in the stator core 36b, the layout of the winding teeth 40 and the non-winding teeth 42 is changed so that the center of the winding teeth 40 coincides with the radial direction of the stator core 36b. Further, the main yoke 44 and the auxiliary yoke 46 are arranged in a direction orthogonal to the winding teeth 40. Also in this case, one end of the narrow side yoke (auxiliary yoke 46) connected to the tooth (winding tooth 40) around which the coil 38 is wound is at the base side of the winding tooth 40 (the outer peripheral side of the stator core 36b). )It is connected to the. Further, the position where the other end of the auxiliary yoke 46 is biased to the base side (outer peripheral side) by a predetermined distance from the tip (inner peripheral side of the stator core 36b) of the tooth (non-winding tooth 42) adjacent to the winding tooth 40. Thus, they are connected via a non-linear connecting portion 130. According to this configuration, the space Yb around the stator core 36b is enlarged, and the effective utilization of the space such as the arrangement of other components is improved.

  FIG. 10 is a plan view of a stator core 36 c that is a third modification of the stator core 36. Unlike the other stator cores 36, 36a, and 36b, the stator core 36c is configured such that one of the stator magnetic paths is not connected and the other is connected by a yoke. That is, the winding tooth 40 is connected only to the non-winding tooth 42 adjacent to one side. That is, the main yoke 44 exists, but the auxiliary yoke 46 shown in FIG. 9 does not exist. With this configuration, the magnetic field passing through the winding teeth 40 is only the magnetic field Q1, and the effect of suppressing the inductance component is improved compared to the other stator cores 36, 36a, 36b, which can contribute to the improvement of the maximum output of the shift switching motor 10. . However, in the case of the stator core 36c, since the auxiliary yoke 46 does not exist, the tooth set 132 of the winding tooth 40 and the non-winding tooth 42 connected by the main yoke 44 exists in a state where it is separated into six pieces. . Therefore, in order to maintain the substantially cylindrical shape as the stator core 36, the stator core 36c is formed by molding six teeth sets 132 with a resin 134, for example. In the example of FIG. 10, as an example, a substantially cylindrical shape is maintained by completely filling a gap between adjacent teeth sets 132. In the modified example, a mold shape using the resin 134 may be appropriately selected. For example, a space where other parts can be arranged is formed, or the other parts are supported or fixed using the resin 134. You may do it. In the motor structure, in the case of a mold using the resin 134, it is generally necessary to take measures for heat dissipation. However, since the shift switching motor 10 is driven mainly at the time of switching between the lock position (parking position) and the unlock position (non-parking position), the drive frequency is not so high and continuous heat generation is unlikely to occur. The resin 134 can be regarded as not affecting the performance of the shift switching motor 10.

  Thus, by selecting (determining) the yoke shape so that the magnetic resistance to the left and right regions around the winding tooth 40 is different, or by making the yoke only on one side, it becomes possible to adjust the flow of the magnetic field, It is possible to suppress (adjust) the inductance component. That is, the performance adjustment (adjustment of the maximum output value) of the shift switching motor 10 can be performed by the shape of the stator core. As a result, the shift switching motor 10 having characteristics corresponding to the specifications can be easily provided.

  In each of the embodiments described above, the motor unit 12 including the intermediate gear 60 and the like is shown as an application example of the shift switching motor 10 as shown in FIG. 1, but is not limited to the configuration example of FIG. 1. For example, the shift switching motor 10 may be provided as a single unit and connected to a separate speed reduction device or the like, and similar effects can be obtained. The configuration of the shift switching device shown in FIG. 3 to FIG. 5 is also an example, and the shift switching motor 10 and the motor unit 12 can be applied as long as the configuration achieves the same function. Can be obtained.

  The stator cores 36, 36a, 36b, 36c shown in FIG. 2 and FIGS. 8 to 10 show examples in which the winding teeth 40 are composed of six pieces. What is necessary is just the structure from which resistance differs. That is, the number of winding teeth 40 can be appropriately selected according to the required motor characteristics, and similar effects can be obtained. In the stator core 36 shown in FIG. 2, an example in which the same number of insertion holes 46 a as the number of auxiliary yokes 46 is formed is shown. In another embodiment, an auxiliary yoke 46 having an insertion hole 46a and an auxiliary yoke 46 having no insertion hole 46a may be provided. For example, the number of insertion hole portions 46a may be increased or decreased as appropriate, such as two. In this case, an enlarged space Y can be formed, and the layout of other components is improved. Further, the insertion hole 46a may be formed in all the auxiliary yokes 46 as shown in FIG. 2, and the insertion hole 46a to be used may be selected. In this case, for example, the arrangement position of the intermediate gear 60 in the motor unit 12 can be changed, and the layout in the motor unit 12 can be improved.

  In the present embodiment, the stator cores 36, 36a, 36b, 36c are applied to the shift switching motor 10. However, the stator cores 36, 36a, 36b, 36c are also applied to motors used for other purposes. It is possible and the same effect can be obtained.

  The embodiments of the present invention are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. The embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Shift switching motor, 12 ... Motor unit, 22 ... Output shaft, 32 ... Stator, 34 ... Rotor, 36 ... Stator core, 38 ... Coil, 40 ... Winding teeth, 42 ... Non-winding teeth, 44 ... Main yoke, 46 ... auxiliary yoke, 46a ... insertion hole portion, 100 ... parking lock device, 130 ... connection portion.

Claims (6)

A motor that is a power source of a drive mechanism that switches a shift position of a shift switching device, the motor including a rotor that rotates together with a rotating shaft, and a stator that is arranged coaxially with the rotor and includes a plurality of teeth. ,
The stator is a shift switching motor having different magnetic resistances with respect to left and right regions around the tooth around which the coil is wound.   2. The shift switching motor according to claim 1, wherein the stator is asymmetric in a magnetic path formation mode with respect to left and right regions around a tooth around which the coil is wound.   3. The shift switching motor according to claim 2, wherein the stator magnetic path is formed in such a manner that a yoke forming one magnetic path is narrower than a yoke forming the other magnetic path.   The narrow yoke connected to the tooth around which the coil is wound has one end connected to the base side of the tooth around which the coil is wound and the other end adjacent to the tooth around which the coil is wound. The shift switching motor according to claim 3, wherein the shift switching motor is connected to a position biased toward the base side by a predetermined distance from the tip of the tooth to be connected via a non-linear connecting portion.   The shift switching motor according to claim 2, wherein one of the formation modes of the magnetic path of the stator is disconnected and the other is connected by a yoke.   The stator has a through hole for component insertion in a yoke connected to the teeth, and the through hole is parallel to the rotating shaft and formed inside the outer shape of the coil in the radial direction of the stator. The shift switching motor according to any one of claims 1 to 5, wherein the shift switching motor is provided.

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