JP2010130830A - Drive device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the total length of a drive device using a wave gear device while preventing a function of the drive device from being deteriorated by heat generation of the wave gear device. <P>SOLUTION: The drive device includes: the wave gear device, an electric motor 11 and a rotation detection device 21. The wave gear device is formed in a substantially bowl shape. The electric motor 11 is in a coaxial state with respect to the wave gear device and includes at least one part disposed in a space formed inside a substantially bowl-shaped wave gear device. Moreover, a rotation detection device 21 is mounted on the electric motor 11 on the side opposite to the wave gear device. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drive device, and more particularly, to a drive device using a wave gear device.

  When a small electric motor is manufactured, its output characteristics are generally high speed and low torque. For this reason, when a small electric motor is used for an application in which the output of the rotating shaft is greatly reduced and the reduced output is required, the wave gear device may be attached to the electric motor.

  The wave gear device includes an annular rigid internal gear, a flexible external gear disposed on the inside, and a flexible external gear that is bent in the radial direction and meshed with the rigid internal gear. And a wave generator for moving the meshing position of both gears in the circumferential direction.

  By attaching an electric motor and a rotation detector to the wave gear device, a drive device using the wave gear device is configured. Here, the rotation detector includes a rotating plate attached to the rotating shaft of the electric motor, and a rotation detecting element that is disposed in proximity to the rotating plate and detects rotation information from the rotating plate, and rotates the rotating shaft of the electric motor. Is detected.

  In the drive device having this configuration, the other end of the rotating shaft of the electric motor is coaxially connected to the wave generator of the wave gear device, and one end of the rotating shaft of the electric motor is attached to the rotating plate of the rotation detector. Thereby, a rotation detector is arrange | positioned on the opposite side of a wave gear apparatus on both sides of an electric motor.

  In the drive device using the wave gear device having the configuration described above, the wave gear device, the electric motor, and the rotation detector are arranged in this order in a coaxial state. In this configuration, the entire length of the drive device becomes long, and a large installation location is required.

Generally, a wave gear device has a substantially bottomed cylindrical shape in appearance and has a dead space inside. An optical rotation detection device is arranged in this inner dead space, thereby shortening the axial direction of the drive device and shortening the overall length of the drive device (for example, Patent Document 1). .
JP 2005-31223 A

  However, when the rotation detection device is arranged in the dead space inside the wave gear device as described above, the ambient temperature of the rotation detection device becomes high due to heat generation of the wave gear device. On the other hand, an electronic element used in an optical rotation detection device has a low heat-resistant temperature and cannot fully exhibit its specification performance at high temperatures.

  For this reason, the drive device in which the rotation detection device is arranged inside the wave gear device cannot sufficiently exhibit the specification performance as the whole device. As described above, it is not appropriate to dispose the optical rotation detection device in the dead space inside the wave gear device as a configuration for shortening the overall length of the drive device.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to shorten the overall length of a drive device using a wave gear device while noting that the function of the drive device does not deteriorate due to heat generated by the wave gear device.

  In order to solve the above-described problem, the drive device according to claim 1 includes an annular first gear member having a plurality of inner teeth formed on the inner peripheral side surface, and a plurality of outer teeth on the outer peripheral side surface. A hat-shaped second gear member that is formed and arranged substantially coaxially inside the first gear member, and a wave generator that is arranged inside the second gear device and forms a wave at the outer periphery. And at least a part of the substantially gear-shaped wave gear device and a space formed inside the second gear member of the substantially gear-shaped wave gear device. An electric motor attached in a coaxial state, and a rotation detection device attached in a coaxial state with respect to the electric motor at a position opposite to the wave gear device across the electric motor.

  In this way, at least a part of the electric motor is arranged in the space formed inside the substantially saddle-shaped wave gear device that is a dead space, and is configured from the wave gear device, the electric motor, and the rotation detection device. The overall length of the drive device can be shortened. In addition, an electric motor having a heat resistant temperature higher than that of the rotation detecting device is arranged inside the wave gear device. Therefore, even when the temperature of the space in which the electric motor is arranged becomes higher due to the heat generated by the wave gear device, the electric motor can sufficiently perform its function, and the function of the entire drive device does not deteriorate.

  The drive device according to claim 2 is the drive device according to claim 1, wherein the electric motor is substantially perpendicular to a stator core body formed in a hollow disk shape and one end surface of the stator core body. A plurality of teeth integrally projecting, a stator core formed of a magnetic material, and a stator coil having a plurality of windings wound around each of the teeth by concentrated winding, The stator core has a stator fixedly disposed on the wave gear device and a substantially rod-shaped main body portion facing the wave generator of the wave gear device, and is disposed rotatably with respect to the stator. The main body portion has one end that protrudes outward from the stator and a magnetic material, is formed in a disk shape, and is opposed to the teeth of the stator core. It is disposed, and a rotor yoke mounted on the wave generator, which is an axial gap type electric motor comprising a rotor having a magnet attached to the rotor yoke at the surface facing the teeth of the stator core.

  Thus, the overall length of the drive device is further shortened by using an axial gap type electric motor suitable for thinning.

  By disposing at least a part of the electric motor in a space formed inside the substantially saddle-shaped wave gear device, the overall length of the drive device can be shortened. In addition, since the electric motor having a higher heat resistance temperature than the rotation detection device is disposed inside the wave gear device, the function of the entire drive device is not deteriorated even when the wave gear device generates heat.

  Next, a drive device 100 using the wave gear device 1 according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view of a drive device according to the first embodiment. FIG. 2 is a cross-sectional view of the drive device according to the first embodiment indicated by a cross-section AA-A-A in FIG. FIG. 3 is an exploded perspective view of the wave gear device in the first embodiment, and FIG. 4 is an exploded perspective view of the electric motor and the rotation detection device in the first embodiment.

  The drive device 100 includes a wave gear device 1, an electric motor 11, and a rotation detection device 21, and the electric motor 11 is coaxially arranged in a space S inside the substantially gear-shaped wave gear device 1. At a position opposite to the device 1, a rotation detection device 21 is attached to the electric motor 11 in a coaxial state.

  As shown in FIG. 3, the wave gear device 1 includes an annular casing member 2, a first gear member 3 that is rotatably disposed inside the casing member 2, and is formed of a rigid member, and a first gear member 3. The second gear member 4 disposed inside the gear member 3 and the wave generator 5 disposed inside the second gear member 4 are formed in a substantially bowl shape.

  Between the casing member 2 and the first gear member 3, a plurality of cylindrical roller members (second sliding members) 6 are arranged at an equal pitch. By being supported by the roller member (second sliding member) 6, the roller member is disposed so as to be rotatable with respect to the casing member 2. On the inner peripheral side surface 3b of the first gearless member 3, a plurality of internal teeth 3a are formed at equal pitches in the circumferential direction in the axial direction.

  The second gear member 4 disposed on the inner side of the first gear member 3 includes a flexible thin plate cylindrical flexible gear portion 4c and an end portion 4f of the flexible gear portion 4c. A thin disc-shaped collar portion 4b integrally formed and an annular mounting portion 4a integrally formed on the outer peripheral edge of the collar portion 4b. The second gear member 4 configured as described above has a so-called hat shape.

  A plurality of external teeth 4d are formed on the outer peripheral side surface 4e of the flexible gear portion 4c at equal pitches in the circumferential direction in the axial direction. The number of teeth (N2) of the plurality of external teeth 4d is set to be two less than the number of teeth (N1) of the plurality of internal teeth 3a formed on the inner peripheral side surface 3b of the first gear member 3 (N2). = N1-2). The flexible gear portion 4 c is disposed inside the first gear member 3. On the other hand, the attachment portion 4 a of the second gear member 4 is attached to the end surface 2 a of the casing member 2 with a bolt 7. In the present embodiment, the number of teeth (N2) of the external teeth 4d is set to be two less than the number of teeth (N1) of the internal teeth 3a (N2 = N1-2), but is not limited to this. The number of teeth (N2) of the external teeth 4d may be set smaller than the number of teeth (N1) of the internal teeth 3a (N2 <N1).

  The wave generator 5 is disposed on the inner side of the second gear member 4 and has a thin cylindrical member (outer peripheral part) 5c formed of a flexible member, and a circumference around the inner wall 5f of the cylindrical member (outer peripheral part) 5c. A plurality of spherical steel balls (first sliding members) 5b arranged in contact with each other at equal pitches and a cylindrical member 5c inside the cylindrical member 5c via the steel balls (first sliding member) 5b. And a cam member 5a that is rotatably arranged. The cam member 5a has an elliptical disk shape.

  In the wave generator 5, the cam member 5a is press-fitted through the steel ball 5b inside the flexible cylindrical member 5c, and the cam member 5a and the cylindrical member 5c are inserted through the steel ball 5b. It is formed integrally with no gap. Therefore, the cylindrical member 5c is imitated by the outer shape of the cam member 5a, and the outer shape of the cylindrical member 5c is also elliptical. Accordingly, when the elliptical disc-shaped cam member 5a rotates, an elliptical wave that rotates is formed in the thin cylindrical member 5c.

  In the cylindrical member 5c, the outer peripheral side surface 5g is in contact with the inner peripheral side surface 4g of the flexible gear portion 4c over the entire circumference, and is the same as the elliptical wave formed and rotated by the rotation of the cam member 5a. An elliptical phase wave is also formed in the flexible gear portion 4c. As the flexible gear portion 4c is displaced in an elliptical shape in this way, the internal teeth 3a of the first gear member 3 of the part of the external teeth 4d of the flexible gear portion 4c located on the long axis of the elliptical shape. When the elliptical wave rotates, the meshing position shifts. Due to the shift of the meshing position, the first and second gear members 3 and 4 move relative to each other.

  The second gear member 4 in which the flexible gear portion 4 c is formed is fixed to the casing member 2. Accordingly, the first gear member 3 rotates relative to the casing member 2 and the second gear member 4 due to the displacement of the meshing position of the internal teeth 3a with respect to the external teeth 4d caused by the rotation of the cam member 5a of the wave generator 5. Is done. In the present embodiment, as described above, the number of teeth N2 of the outer teeth 4d is two less than the number of teeth N2 of the inner teeth 3a (N2 = N1-2). Therefore, when the cam member 5a rotates once (360 degrees), the first gear member 3 is converted into the number of teeth of the internal teeth 3a and rotated by two angles. Therefore, the reduction ratio of the first gear member 3 with respect to the rotation of the cam member 5a of the wave gear device 1 of the present embodiment is N1: 2, and the rotation of the cam member 5a causes the first gear member 3 to rotate. The rotation is decelerated to 2 / N1.

  Next, the configuration of the electric motor 11 and the attachment of the electric motor 11 to the wave gear device 1 in the drive device of the present embodiment will be described with reference to FIGS.

  The electric motor 11 includes a stator 12, a rotor 15, a rotating shaft 18 and a power distribution board 19. The stator 12 includes a stator core 13 and a stator coil 14. The stator core 13 is formed of a magnetic material, and is formed integrally and protrudes substantially vertically from a hollow disk-shaped stator core body 13a and one end face 13c of the stator core body 13a. A plurality of teeth 13b. On the other hand, the stator coil 14 has a plurality of windings 14a wound around each tooth 13b by concentrated winding.

  In the present embodiment, the stator core 13 is formed of a so-called dust magnetic material obtained by compression-molding soft magnetic powder. Needless to say, the stator core 13 is not limited to being formed of a dust magnetic material, and may be formed by laminating thin plate-shaped magnetic steel plates.

  Electric power is supplied to each winding 14 a of the stator coil 14 by a hollow disk-shaped power distribution board 19. The distribution board 19 has the same number of insertion holes 19 a as the plurality of teeth 13 b of the stator core 13. The teeth 13 b are inserted into the insertion holes 19 a, and the distribution board 19 is attached to the stator core 13. Then, the winding end 14 b at the start and end of winding 14 a is electrically and mechanically connected to the power distribution board 19.

  The stator 12 of the electric motor 11 is attached to the bottom 20 a of the housing 20. On the other hand, the flange portion 20 b of the housing 20 is fixed to the casing member 2 by the bolt 7 together with the mounting portion 4 a of the second gear member 4, and the housing 20 to which the stator 12 is attached is fixed to the wave gear device 1. . By fixing the housing 20 to the wave gear device 1 in this way, the stator 12 attached to the housing 20 is in a state where each tooth 12b of the stator core 13 is directed to the wave generator 5, that is, a hat-shaped second. The gear member 4 is fixedly disposed on the wave gear device 1 in a state of being directed from the collar portion 4b of the gear member 4 to the flexible gear portion 4c.

  An annular fixed wall 20 c is integrally formed toward the wave gear device 1 at the center of the bottom 20 a of the housing 20. A bearing 41 is press-fitted and fixed inside the fixed wall 20c.

  The rotary shaft 18 has a substantially cylindrical main body portion 18a with one end 18d projecting outward from the stator 12, and a disk shape integrally formed with the main body portion 18a radially outward from the other end 18c of the main body portion 18a. And a locking portion 18b. A diameter-reduced step portion 18e is formed at one end 18d of the main body portion 18a of the rotary shaft 18, and the step portion 18e is inserted and fixed to the bearing 41 so that the rotary shaft 18 is rotatable with respect to the stator 13. Be placed.

  The center of the cam member 5a of the wave generator 5 has a circular concave shape, and a flange portion 5h is formed at the bottom of the concave shape. Then, by attaching the locking portion 18b to the flange portion 5h, the disk-shaped locking portion 18b is attached to the cam member 5a.

  The rotor 15 includes a rotor yoke 16 and a magnet. The rotor yoke 16 is formed of a magnetic material and has a disk shape. The rotor yoke 16 is attached to the cam member 5 a of the wave generator 5 in a state of being opposed to each tooth 13 b of the stator core 13. The magnet 17 is integrally formed in a ring shape, and a plurality of magnetic poles having different polarities are formed alternately at equal pitches in the circumferential direction. The stator core 13 is attached to the rotor yoke 16 on the surface facing each tooth 13b. As described above, in the electric motor 11 of the present embodiment, the rotor 15 is opposed to the stator 12 in the rotation axis direction, and is a so-called axial gap type electric motor.

  In drive device 100 of the present embodiment, rotation detection device 21 is attached on housing 20 with respect to electric motor 11. The rotation detection device 21 is mounted on the housing 20 at a position opposite to the wave gear device 1 with the electric motor 11 interposed therebetween. Note that the rotation detection device 21 of the present embodiment is an optical encoder.

  An insertion hole 20 d is formed at the center of the housing 20, and one end 18 d of the rotary shaft 18 projects from the insertion hole 20 d toward the outside of the housing 20. A rotating plate 22 of the rotation detecting device 21 is attached to the protruding end portion 18f of one end 18d, and a plurality of reflective slits are formed radially on the disk surface 22a of the rotating plate 22.

  The rotation signal processing unit 24 includes a rotation detection element 23, and the rotation signal processing unit 24 is attached to the rotation detection housing 20. At this time, the rotation detecting element 23 is disposed at a position facing and close to the disk surface 22 a of the rotating plate 22.

  The rotation detection element 23 is an optical sensor. The rotation detection element 23 detects a change in light from the reflection slit, supplies a detection signal to the rotation signal processing unit 24, and rotates the detection signal from the rotation detection unit 23. Processing is performed by the unit 24, and the rotation signal of the rotating plate 22 is supplied to a driver (not shown) provided outside the electric motor 11. A cover body 25 that covers the rotating plate 22 and the rotation processing unit 24 is attached to the housing 20 in order to protect the rotating plate 22 and the rotation processing unit 24 from dust and the like from the outside.

  In the driving device 100 of the present embodiment, since a high-resolution optical encoder is used as the rotation detection device 21, the rotation of the rotating shaft 18 of the electric motor 11 can be positioned with high rotation accuracy.

  Next, the effect of the drive device 100 in the embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a schematic diagram illustrating attachment of the electric motor 11 to the wave gear device 1, and FIG. 6 is a cross-sectional view of the driving device 100 illustrating the entire length of the driving device 100.

  In the wave gear device 1 of the present embodiment, since the hat-shaped second gear member 4 is used, a space S is formed inside the second gear member 4, and the overall shape of the wave gear device 1 is as follows. It has a substantially bowl shape. Usually, this space S is a dead space.

  The drive device 100 of the present embodiment is configured such that a part of the electric motor 11 is disposed in a space S formed inside the substantially saddle-shaped wave gear device 1. That is, a part of the stator 12 of the electric motor 11 and the rotor 15 are arranged in the space S. As a result, the overall length L1 of the drive device 100 can be shortened as shown in FIG. Furthermore, since the axial gap type electric motor 11 with a short shaft length is employed in the present embodiment, the total length L1 is even shorter.

  In the present embodiment, not the rotation detection device 21 but the electric motor 11 is arranged in the space S formed inside the wave gear device 1. In general, the rotation detection device 21 that is an optical encoder has a low heat-resistant temperature of an electronic element to be used, so that its specification performance cannot be sufficiently exhibited in a high temperature state.

  On the other hand, the wave gear device 1 generates heat due to a mechanical loss caused when the inner teeth 3 a of the first gear member 3 and the outer teeth 4 d of the second gear member mesh with each other, and a space S formed inside the wave gear device 1. The temperature of becomes high. Therefore, when the rotation detection device 21 is arranged in the space S where the temperature is high, the rotation detection of the electric motor 11 cannot be performed with high accuracy, and there is a concern that the function of the drive device 100 may be deteriorated as a whole. The

  On the other hand, in the present embodiment, the configuration in which the electric motor 11 that can sufficiently perform its function even in a high temperature environment as compared with the rotation detection device 21 is disposed in the space S formed inside the wave gear device 1. It is said. As a result, even when the temperature of the space S becomes high due to the heat generated by the wave gear device 1, the electric motor 11 can sufficiently exhibit its function and the function of the drive device 100 as a whole does not deteriorate.

  Next, a driving device 200 according to a second embodiment of the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional view of the driving apparatus of the second embodiment.

  The drive device 200 of the second embodiment differs from the drive device 100 of the first embodiment only in the rotation detection device 51, and the other parts are the same. Accordingly, only the configuration of the rotation detection device 51 will be described below, and description of the other parts will be omitted.

  In the drive device 200 of the present embodiment, a rotation detection device 51 is attached to the housing 20, and the rotation detection device 51 is provided on the opposite side of the wave gear device 1 with the electric motor 11 interposed therebetween. The rotation detection device 51 of the present embodiment is a magnet type encoder.

  An insertion hole 20 d is formed at the center of the housing 20, and one end 18 d of the rotary shaft 18 projects from the insertion hole 20 d toward the outside of the housing 20. A rotating plate 52 of the rotation detecting device 51 is attached to the tip 18f of the protruding one end 18d.

  A ring-shaped guide portion 52b is integrally formed on the end surface 52a of the rotating plate 52, and a ring-shaped sensor magnet 52c is guided and attached to the outer peripheral side surface 52d of the guide portion 52b on the end surface 52a of the rotating plate 52. Yes. In the sensor magnet 52c, a plurality of magnetic poles having different polarities are formed at equal pitches in the circumferential direction.

  The rotation signal processing unit 24 provided with the rotation detection element 53 is attached to the rotation detection housing 20. At this time, the rotation detecting element 53 is arranged at a position close to the outside of the rotating plate 22 in the radial direction of the sensor magnet 53c. In this way, the rotation detecting device 53 can be thinned by arranging the rotation detecting element 53 outside the sensor magnet 53c in the radial direction.

  The rotation detection element 53 is a magnetoresistive effect element, and the rotation detection element 53 detects a change in the polarity of the magnetic pole formed in the sensor magnet 53 and supplies a detection signal to the rotation signal processing unit 54. The rotation signal processing unit 54 processes the detection signal from the rotation detection unit 53 and supplies the rotation signal of the rotating plate 52 to a driver (not shown) provided outside the electric motor 11. A cover body 55 that covers the rotating plate 52 and the rotation processing unit 54 is attached to the housing 20 in order to protect the rotating plate 52 and the rotation processing unit 54 from dust and the like from the outside.

  In the driving device 200 of the present embodiment, a magnetic encoder is used as the rotation detecting device 51, and the magnetic encoder has a rotation detection accuracy as compared with the optical encoder used in the first embodiment. Inferior. However, since the magnetic encoder is less expensive than the optical encoder, this embodiment is used when it is not necessary to position the rotation of the rotating shaft 18 of the electric motor 11 with high rotation accuracy by the optical encoder. It is effective to use a magnetic encoder as shown in FIG.

  Furthermore, in the rotation detection device 51 of the present embodiment, the rotation detection device 53 is thinned by disposing the rotation detection element 53 on the radially outer side of the sensor magnet 53c. Therefore, the full length L2 of the drive device 200 is shorter than the full length L1 of the drive device 100 of the first embodiment.

It is a perspective view of the drive device in the 1st Embodiment of the present invention. It is sectional drawing of the drive device in 1st Embodiment instruct | indicated by the cross section AA-A-A in FIG. It is an expanded perspective view of the wave gear device in a 1st embodiment of the present invention. It is an expansion perspective view of the electric motor in a 1st embodiment of the present invention. It is a schematic diagram explaining attachment of the electric motor 1 to the wave gear apparatus in the 1st Embodiment of this invention. FIG. 6 is a cross-sectional view of the driving device for explaining the entire length of the driving device. It is sectional drawing of the drive device explaining the full length of a drive device. It is sectional drawing of the drive device in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wave gear apparatus 2 Casing member 3 1st gear member 3a Internal tooth 4 2nd gear member 4a Attachment part 4b Collar part 4c Flexible gear part 4d External tooth 5 Wave generator 5a Cam member 5b 1st sliding Member 5c Cylindrical member 11 Electric motor 12 Stator 13 Stator core 13a Stator core main body 13b Teeth 14 Stator coil 14a Winding 15 Rotor 16 Rotor yoke 17 Magnet 18 Rotating shaft 18a Main body 18b Locking portion 18c Other end 18d One end 21 Rotation detecting device 22 Rotating plate 23 Rotation detection element 51 Rotation detection device 52 Rotation plate 53 Rotation detection element

Claims (5)

A ring-shaped first gear member having a plurality of inner teeth formed on the inner peripheral side surface, and a plurality of outer teeth formed on the outer peripheral side surface, and disposed substantially coaxially inside the first gear member. A substantially saddle-shaped wave gear device having a hat-shaped second gear member and a wave generator disposed inside the second gear device and forming a wave on the outer periphery;
An electric motor, at least part of which is disposed in a space formed inside the second gear member of the substantially saddle-shaped wave gear device, and is attached to the wave gear device in a substantially coaxial state;
A drive device comprising: a rotation detection device attached coaxially to the electric motor at a position opposite to the wave gear device across the electric motor. The electric motor is
A stator core body formed in a hollow disk shape, and a plurality of teeth integrally formed substantially vertically from one end face of the stator core body, a stator core formed of a magnetic material, and each of the teeth A stator coil having a plurality of windings each wound by concentrated winding, and the teeth of the stator core are fixedly arranged on the wave gear device toward the wave generator of the wave gear device A stator,
A rotating shaft that has a main body formed in a substantially rod shape, is rotatably arranged with respect to the stator, and has one end of the main body protruding outward from the stator;
A rotor yoke made of a magnetic material, formed in a disk shape, disposed opposite to the teeth of the stator core and attached to the wave generator, and a magnet attached to the rotor yoke on a surface facing the teeth of the stator core. The drive device according to claim 1, wherein the drive device is an axial gap type electric motor including: The rotation detection device is formed in a substantially disk shape, and a rotation plate attached to one end of the rotation shaft;
The drive device according to claim 2, further comprising: a rotation detection element that is disposed in proximity to the rotation plate and detects rotation information from the rotation plate.   In the rotation detection device, the rotation detection element is an optical sensor, and a plurality of reflection slits are formed radially on the disk surface of the rotation plate, and the rotation detection element detects a change in light from the reflection slit. The drive device according to claim 3, wherein the drive device is an optical encoder that detects rotation of the rotating plate. In the rotation detection device, the rotation detection element is a magnetoresistive effect element, and a link-shaped sensor magnet in which a plurality of magnetic poles having different polarities are formed at equal pitches in the circumferential direction is attached to the rotation plate. The rotation detection element is a magnet type encoder that is arranged on the outside in the radial direction of the sensor magnet and detects the rotation of the rotating plate by detecting a change in the polarity of the magnetic pole of the sensor magnet. The drive device according to claim 3.

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