WO2024100883A1 - Electric drive device - Google Patents

Electric drive device Download PDF

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Publication number
WO2024100883A1
WO2024100883A1 PCT/JP2022/042080 JP2022042080W WO2024100883A1 WO 2024100883 A1 WO2024100883 A1 WO 2024100883A1 JP 2022042080 W JP2022042080 W JP 2022042080W WO 2024100883 A1 WO2024100883 A1 WO 2024100883A1
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WO
WIPO (PCT)
Prior art keywords
output shaft
protrusion
power transmission
motor
transmission member
Prior art date
Application number
PCT/JP2022/042080
Other languages
French (fr)
Japanese (ja)
Inventor
裕人 佐藤
Original Assignee
株式会社ジェイテクト
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Filing date
Publication date
Application filed by 株式会社ジェイテクト filed Critical 株式会社ジェイテクト
Priority to PCT/JP2022/042080 priority Critical patent/WO2024100883A1/en
Publication of WO2024100883A1 publication Critical patent/WO2024100883A1/en

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/10—Casings or enclosures characterised by the shape, form or construction thereof with arrangements for protection from ingress, e.g. water or fingers

Definitions

  • This disclosure relates to an electric drive device.
  • the steering device of Patent Document 1 has a belt transmission mechanism.
  • the belt transmission mechanism is configured to transmit the torque of the motor to the steered shaft.
  • the steered shaft has a ball nut.
  • the belt transmission mechanism has a drive pulley provided on the output shaft of the motor, a driven pulley provided on the ball nut of the steered shaft, and a belt wound around the drive pulley and the driven pulley.
  • the steering shaft and belt transmission mechanism are housed in a housing.
  • the motor is attached to the outside of the housing.
  • the output shaft of the motor is connected to the drive pulley via a drive shaft.
  • the drive shaft is rotatably supported relative to the housing via a bearing.
  • the bearing is located axially between the drive pulley and the output shaft of the motor.
  • An electric drive device includes a motor configured to generate a driving force for driving a driven object, and a transmission mechanism configured to transmit the driving force of the motor to the driven object.
  • the motor has a motor case including an end wall having a through hole penetrating in the axial direction, and an output shaft penetrating the through hole in the axial direction without contacting the inner peripheral surface of the through hole and supported rotatably on the inner peripheral surface of the motor case.
  • the transmission mechanism has a cylindrical power transmission member connected to the output shaft rotatably and integrally on the outside of the motor case.
  • the motor case has a cylindrical protrusion on the outer surface of the end wall surrounding the periphery of the through hole.
  • FIG. 1 is a configuration diagram of a steering mechanism according to an embodiment of an electric drive device
  • FIG. 2 is a cross-sectional view of the motor of FIG. 1
  • 3 is a cross-sectional view of a connection portion between an output shaft and a drive pulley of the motor in FIG. 2.
  • 3 is a cross-sectional view showing a first configuration pattern of a foreign object intrusion prevention structure in the motor of FIG. 2.
  • 3 is a cross-sectional view showing a second configuration pattern of the foreign object intrusion prevention structure in the motor of FIG. 2.
  • FIG. 3 is a cross-sectional view of a first bearing of the motor of FIG. 2 .
  • the steering device of a vehicle has a steering mechanism 11.
  • the steering mechanism 11 is a mechanical part that steers steered wheels 12 of the vehicle in response to the steering of a steering wheel.
  • the steering mechanism 11 has a pinion shaft 21, a steered shaft 22, and a housing 23.
  • the housing 23 rotatably supports the pinion shaft 21.
  • the housing 23 also accommodates the steered shaft 22 so that it can reciprocate in the axial direction.
  • the pinion shaft 21 is arranged to intersect with the steered shaft 22.
  • the pinion teeth 21a of the pinion shaft 21 mesh with the rack teeth 22a of the steered shaft 22. Both ends of the steered shaft 22 are connected to the steered wheels 12 via rack ends 24 and tie rods 25.
  • the steering device is a steer-by-wire type steering device or an electric power steering device. If the steering device is a steer-by-wire type steering device, the pinion shaft 21 is not mechanically connected to the steering wheel. If the steering device is an electric power steering device, the pinion shaft 21 is mechanically connected to the steering wheel via a steering shaft.
  • the steering mechanism 11 includes a motor 31, a transmission mechanism 32, and a conversion mechanism 33.
  • the motor 31 is an electric motor and is a source of a steering force applied to the steering shaft 22.
  • the steering force is a force for steering the steered wheels 12.
  • the motor 31 is, for example, a three-phase brushless motor.
  • the transmission mechanism 32 is, for example, a belt transmission mechanism.
  • the transmission mechanism 32 transmits the rotation of the motor 31 to the conversion mechanism 33.
  • the conversion mechanism 33 is, for example, a ball screw mechanism.
  • the conversion mechanism 33 converts the rotation transmitted via the transmission mechanism 32 into axial motion of the steered shaft 22.
  • the steered angle ⁇ w of the steered wheels 12 is changed by the axial movement of the steered shaft 22.
  • the steered shaft 22 is a drive target of the motor 31.
  • the motor 31 functions as a steering motor.
  • the steering motor generates a steering force for steering the steered wheels 12.
  • the motor 31 functions as an assist motor.
  • the assist motor generates an assist force for assisting the operation of the steering wheel.
  • the steering mechanism 11 corresponds to an electric drive device.
  • the electric drive device drives a driven object by the driving force of an electric motor that converts electric energy into mechanical energy.
  • ⁇ Configuration of Motor 31> Next, the configuration of the motor 31 will be described in detail.
  • the motor 31 has a motor body 40 and a control device 50.
  • the motor body 40 and the control device 50 are integrated together.
  • the motor body 40 has a motor case 41.
  • the motor case 41 is cylindrical and has a circular cross-sectional shape.
  • a first end of the motor case 41 is closed by an end wall.
  • a second end of the motor case 41 is open in the axial direction.
  • the motor case 41 has a first bearing support portion 41A.
  • the first bearing support portion 41A is a hole provided on the inner surface of the end wall of the motor case 41 and has a circular cross-sectional shape.
  • the first bearing support portion 41A is open in the axial direction to the outside of the motor case 41 via a first through hole 41B.
  • the motor body 40 has a lid 42.
  • the lid 42 is fitted into the second end of the motor case 41 to close the opening of the second end.
  • the lid 42 has a second bearing support portion 42A and a magnet accommodating portion 42B.
  • the second bearing support portion 42A is a hole that opens in the axial direction on the inside of the motor case 41 and has a circular cross-sectional shape.
  • the magnet accommodating portion 42A is a hole that opens in the axial direction on the outside of the lid 42 and has a circular cross-sectional shape.
  • the interior of the first bearing support portion 42A and the interior of the magnet accommodating portion 42B are axially connected to each other via a second through-hole 42C.
  • the motor body 40 has a stator 43, an output shaft 44, a rotor 45, a first bearing 46, a second bearing, and a magnetic flux generator 48.
  • the stator 43 has a stator core 43A and a stator coil 43B provided in the stator core 43A.
  • the stator core 43A is cylindrical with a circular cross-sectional shape.
  • the stator core 43A is fixed in a fitted state against the inner circumferential surface of the motor case 41.
  • the output shaft 44 is rotatably supported relative to the motor case 41 via a first bearing 46 and a second bearing 47.
  • the first bearing 46 is attached to a first bearing support portion 41A of the motor case 41.
  • the second bearing 47 is attached to a second bearing support portion 42A of the lid 42.
  • the output shaft 44 passes through the motor case 41 in the axial direction.
  • the first end of the output shaft 44 protrudes axially to the outside of the motor case 41 via a first through hole 41B of the motor case 41.
  • the second end of the output shaft 44 is located inside the magnet storage portion 42B via a second through hole 42C of the lid 42.
  • the rotor 45 is located inside the stator 43.
  • the rotor 45 has a rotor core 45A and a permanent magnet 45B.
  • the rotor core 45A is cylindrical with a circular cross-sectional shape and is fixed to the outer circumferential surface of the output shaft 44.
  • the permanent magnet 45B is cylindrical with a circular cross-sectional shape and is fixed to the outer circumferential surface of the rotor core 45A. The rotor 45 can rotate without contacting the inner circumferential surface of the stator 43.
  • the magnetic flux generator 48 is provided at the second end of the output shaft 44.
  • the magnetic flux generator 48 has a magnet 48A, a holder 48B, and a spacer 48C.
  • the magnet 48A is cylindrical.
  • the magnet 48A is a so-called two-pole magnet. Half of the diameter of the magnet 48A is magnetized to the north pole, and the remaining half is magnetized to the south pole.
  • the magnet 48A is attached to the output shaft 44 via the holder 48B.
  • the holder 48B is made of a non-magnetic material.
  • the non-magnetic material may be a synthetic resin, an aluminum alloy, or a zinc alloy.
  • the holder 48B is cylindrical with a circular cross-sectional shape. A first end of the holder 48B is open in the axial direction. A second end of the holder 48B is closed by an end wall. The second end is the end of the holder 48B opposite the first end in the axial direction.
  • the holder 48B has a flange portion that protrudes radially outward. The flange portion is provided on the outer peripheral surface of the second end of the holder 48B. The second end face including the flange portion of the holder 48B is a plane perpendicular to the axial direction.
  • the magnet 48A is fitted inside the holder 48B.
  • the magnet 48A and the end wall of the holder 48B are maintained in axial contact with each other.
  • the first end of the holder 48B is fixed in a fitted state to the outer circumferential surface of the second end of the output shaft 44.
  • the spacer 48C like the holder 48B, is made of a non-magnetic material.
  • the spacer 48C is cylindrical and is interposed between the magnet 48A and the second end of the output shaft 44.
  • the control device 50 has a cover 51 and a substrate 52.
  • the cover 51 is, for example, cylindrical with a circular cross-sectional shape.
  • a first end of the cover 51 is open in the axial direction.
  • a second end of the cover 51 is closed by an end wall. The second end is the end of the cover 51 axially opposite the first end.
  • the cover 51 is fixed to the second end of the motor case 41 with the opening facing the motor case 41.
  • the board 52 is housed inside the cover 51.
  • the board 52 is fixed to the cover 51 so as to be perpendicular to the axial direction of the output shaft 44.
  • the board 52 faces the magnetic flux generator 48 in the axial direction.
  • the board 31 has an MPU (micro processing unit) 52A, an inverter circuit 52B, and a rotation angle sensor 52C.
  • the MPU 52A and the rotation angle sensor 52C are provided, for example, on a first surface of the substrate 52.
  • the first surface is the surface of the substrate 52 that faces the motor body 40 in the axial direction.
  • the rotation angle sensor 52C faces the magnetic flux generator 48 in the axial direction.
  • the magnetic field generated by the magnetic flux generator 48 is applied to the rotation angle sensor 52C.
  • the inverter circuit 52B is provided, for example, on a second surface of the substrate 52.
  • the second surface is the surface of the substrate 52 opposite the first surface.
  • the inverter circuit 52B has multiple switching elements. Based on switching commands generated by the MPU 52A, the switching elements perform switching operations to generate three-phase AC power. The AC power is supplied to the stator coils 43B of each of the three phases via power supply paths (not shown).
  • the rotation angle sensor 52C is a magnetic sensor, for example an MR sensor (magnetoresistive effect sensor).
  • the direction of the magnetic field applied to the rotation angle sensor 52C changes according to the rotation angle of the rotor 45.
  • the rotation angle of the rotor 45 is also the rotation angle of the output shaft 44.
  • the rotation angle sensor 52C generates an electrical signal according to the change in the direction of the magnetic field.
  • the magnetic flux generator 48 is the detection target of the rotation angle sensor 52C.
  • the MPU 52A calculates the rotation angle of the rotor 45 based on the electrical signal generated by the rotation angle sensor 52.
  • the MPU 52A generates a switching command for the inverter circuit 52B based on the rotation angle of the rotor 45.
  • the switching command is a motor control signal for controlling the drive of the motor main body 40.
  • the motor 31 has the following concerns. For example, when assembling the motor 31, it is considered that an external force acts on the first end of the output shaft 44 when the first end of the output shaft 44 hits some object.
  • the external force is, for example, a force in a direction from the first end to the second end of the output shaft 44. Therefore, when an external force acts on the first end of the output shaft 44, the output shaft 44 may move in the axial direction relative to the inner ring of the first bearing 46 and the inner ring of the second bearing 47. As a result, the magnetic flux generator 48 provided on the second end of the output shaft 44 may come into contact with the rotation angle sensor 52C in the axial direction. Therefore, in this embodiment, the following configuration is adopted as the motor 31.
  • the output shaft 44 has a large diameter portion 44A.
  • the large diameter portion 44A has an outer diameter larger than other portions of the output shaft 44.
  • the large diameter portion 44A is located midway between the first end and the second end of the output shaft 44A.
  • a rotor core 45A is attached to the outer circumferential surface of the large diameter portion 44A.
  • the large diameter portion 44A has a restricting surface 44B.
  • the restricting surface 44B is an end surface of the large diameter portion 44A that faces the inner ring of the second bearing 47 in the axial direction.
  • the restricting surface 44B is a flat surface that extends in a direction perpendicular to the axial direction.
  • a first gap ⁇ 1 is formed in the axial direction between the magnetic flux generator 48 and the rotation angle sensor 48.
  • a second gap ⁇ 2 is formed in the axial direction between the regulating surface 44A and the inner ring of the second bearing 47.
  • the first gap ⁇ 1 and the second gap ⁇ 2 are set to satisfy the following relational expression (0).
  • the second gap ⁇ 2 is narrower than the first gap ⁇ 1. Therefore, when the output shaft 44 moves axially toward the rotation angle sensor 52C due to an external force, the regulating surface 44B comes into axial contact with the inner ring of the second bearing 4 before the magnetic flux generator 48 comes into axial contact with the rotation angle sensor 52C. Therefore, even if the output shaft 44 moves axially due to an external force, the magnetic flux generator 48 is prevented from coming into axial contact with the rotation angle sensor 52C.
  • the transmission mechanism 32 has a driving pulley 32A, a belt 32B, and a driven pulley (not shown).
  • the first end of the output shaft 44 protrudes outside the motor case 41.
  • the driving pulley 32A is cylindrical with a circular cross-sectional shape.
  • the driving pulley 32A is fixed in a state of being fitted into the outer circumferential surface of the first end of the output shaft 44.
  • the driving pulley 32A has a first end and a second end. The first end is an end of the driving pulley 32A that is closer to the motor case 41 in the axial direction.
  • the second end is an end of the driving pulley 32A that is closer to the motor case 41 in the axial direction.
  • the driven pulley is attached to the outer circumferential surface of a ball nut of the conversion mechanism 33.
  • the belt 32B is made of, for example, rubber.
  • the belt 32B is endless and is wound between the driving pulley 32A and the driven pulley.
  • the outer circumferential surface of the portion of the belt 32B wound around the drive pulley 32A is located, for example, radially outside the first through hole 41B.
  • the torque of the motor 31 is transmitted to a ball nut of the conversion mechanism 33 via the drive pulley 42A, the belt 32B, and the driven pulley.
  • the drive pulley 32A is a power transmission member.
  • the driving pulley 32A and the driven pulley may be timing pulleys having teeth on their outer circumferential surfaces.
  • the belt 32B may be a timing belt having teeth on its inner circumferential surface.
  • the driving pulley 32A may have a flange portion 32C.
  • the flange portion 32C is a portion of the driving pulley 32A for restricting the axial movement of the belt 32B.
  • the flange portion 32C is provided, for example, around the entire circumference of the outer circumferential surface of the second end portion of the driving pulley 32A.
  • the outer circumferential surface of the flange portion 32C is, for example, located radially inward relative to the outer circumferential surface of the portion of the belt 32B wound around the driving pulley 32A.
  • the outer circumferential surface of the flange portion 32C is, for example, located radially outward relative to the inner circumferential surface of the portion of the belt 32B wound around the driving pulley 32A.
  • the flange portion 32C restricts the movement of the belt 32B in the direction from the first end portion to the second end portion of the driving pulley 32A.
  • the power transmission mechanism 32 is a belt power transmission mechanism
  • the belt 32B wears with long-term use of the power transmission mechanism 32.
  • wear powder generated by this wear may enter the inside of the first bearing 46 that supports the output shaft 44 of the motor 31, thereby hindering the smooth operation of the first bearing 46. Therefore, in this embodiment, the following configuration is adopted to prevent foreign matter such as wear powder from entering the inside of the first bearing 46.
  • the motor case 41 has a protrusion 41C.
  • the protrusion 41C is provided at a first end of the motor case 41.
  • the protrusion 41C is tubular with a circular cross-sectional shape and surrounds the periphery of the first through hole 41B.
  • the protrusion 41C extends axially outward from a first end face of the motor case 41.
  • the first end face is the outer surface of the end wall of the motor case 41.
  • the protrusion 41 has a tip face.
  • the tip face is the end face of the protrusion 41C opposite to the first end face of the motor case 41.
  • the tip face is a flat surface extending in a direction perpendicular to the axial direction.
  • the inner diameter of the protrusion 41C is the same as the inner diameter of the first through hole 41B.
  • the axial gap L1 between the motor case 41 and the drive pulley 32A is narrowed by the axial length of the protrusion 41C. This prevents foreign matter such as wear powder from the belt 32B from entering the inside of the motor case 41.
  • the axial gap L1 is an entry path for foreign matter such as wear powder from the belt 32B.
  • the first configuration pattern is a mode in which the inner diameter D1 of the protrusion 41 and the outer diameter D2 of the drive pulley 32A satisfy the following relational expression (1).
  • the outer diameter D2 is the outermost diameter of the drive pulley 32A.
  • the drive pulley 32B has a flange portion 32C
  • the outermost diameter of the drive pulley 32B is the outer diameter of the flange portion 32C.
  • the relationship (1) indicates that the inner diameter D1 of the protrusion 41C is smaller than the outer diameter D2 of the drive pulley 32A to the extent that the tip surface of the protrusion 41C axially faces the second end surface of the drive pulley 32A.
  • the protrusion 41C has a first outer inclined surface 41D.
  • the first outer inclined surface 41D is provided around the entire circumference of the outer corner between the outer peripheral surface of the protrusion 41C and the tip surface of the protrusion 41C.
  • the first outer inclined surface 41D is inclined so that the outer diameter becomes smaller toward the tip of the protrusion 41C.
  • the drive pulley 32A has a second outer inclined surface 32D.
  • the second outer inclined surface 32D is provided around the entire circumference of the outer corner between the second end face of the drive pulley 32A and the outer circumferential surface of the flange portion 32C.
  • the second outer inclined surface 32D is inclined so that the outer diameter becomes smaller toward the second end face of the drive pulley 32A.
  • the axial gap L1 includes a first inner gap L11 and a first outer gap L12.
  • the first inner gap L11 is the region of the axial gap L1 on the radially inner side, which is the region of the axial gap L1 between the tip surface of the protrusion 41C and the second end surface of the drive pulley 32A.
  • the first outer gap L12 is the region of the axial gap L1 on the radially outer side, which is the region of the axial gap L1 between the tip surface of the protrusion 41C and the second outer inclined surface 32D of the drive pulley 32A.
  • the axial length of the first outer gap L12 increases as it moves radially outward.
  • the axial length of the first outer gap L12 is maximum between the tip surface of the protrusion 41C and the outer corner where the second outer inclined surface 32D and the outer peripheral surface of the flange portion 32C intersect.
  • the axial length of the first outer gap L12 is longer than the axial length of the first inner gap L11.
  • the first outer gap L12 is an entrance for foreign matter.
  • the tip surface of the projection 41C faces the second end surface of the drive pulley 32A in the axial direction. Therefore, when the drive pulley 32A is assembled to the output shaft 44, the tip surface of the projection 41C and the second end surface of the drive pulley 32A may come into contact with each other in the axial direction due to variations in axial assembly tolerances. Therefore, the first inner gap L11 may be required to have a predetermined axial length in order to absorb the axial assembly tolerances of the drive pulley 32A relative to the output shaft 44.
  • the second configuration pattern is a mode in which the inner diameter D1 of the protrusion 41C and the outer diameter D2 of the drive pulley 32A satisfy the following relational expression (2).
  • the outer diameter D2 is the outermost diameter of the drive pulley 32A.
  • the outermost diameter of the drive pulley 32B is the outer diameter of the flange portion 32C.
  • the relational expression (2) includes the conditions that the inner diameter D1 of the protrusion 41C and the outer diameter D2 of the drive pulley 32A are the same, and that the inner diameter D1 of the protrusion 41C is slightly smaller than the outer diameter D2 of the drive pulley 32A.
  • “Slightly smaller” means, for example, that the tip surface of the protrusion 41C faces the second outer inclined surface 32D of the drive pulley 32A in the axial direction.
  • the inner diameter D1 of the protrusion 41C is ideally set to be the same as the outer diameter D2 of the drive pulley 32A.
  • the drive pulley 32A has a second outer inclined surface 32D, similar to the first configuration pattern described above.
  • the axial gap L1 includes a second inner gap L21 and a second outer gap L22.
  • the first inner gap L21 is the region of the axial gap L1 on the radially inner side, which is the region of the axial gap L1 between the tip surface of the protrusion 41C and the second end surface of the drive pulley 32A.
  • the second outer gap L22 is the region of the axial gap L1 on the radially outer side, which is the region of the axial gap L1 between the tip surface of the protrusion 41C and the outer corner where the second outer inclined surface 32D and the outer peripheral surface of the flange portion 32C intersect.
  • the axial length of the second outer gap L22 is longer than the axial length of the second inner gap L21.
  • the second outer gap L22 is an entrance for foreign matter.
  • the axial length of the second outer gap L22 is set to, for example, the same length as the axial length of the first inner gap L11 in the first configuration pattern. Therefore, the axial length of the second outer gap L22 is shorter than the axial length of the first outer gap L12 in the first configuration pattern. That is, compared to the first configuration pattern shown in FIG. 4, the tip surface of the protrusion 41C is axially closer to the second end surface of the drive pulley 32A by the difference between the axial lengths of the first outer gap L12 and the second outer gap L22. Therefore, the axial length of the second inner gap L21 is shorter than the axial length of the first inner gap L11 in the first configuration pattern.
  • the intrusion path of foreign matter in the second configuration pattern consisting of the second outer gap L22 and the second inner gap L21 is axially narrower than the intrusion path of foreign matter in the first configuration pattern consisting of the first outer gap L12 and the first inner gap L11.
  • the second configuration pattern includes a case where the inner diameter D1 of the protrusion 41C is slightly smaller than the outer diameter D2 of the drive pulley 32A.
  • the inner corner of the protrusion 41C faces the second outer inclined surface 32D of the drive pulley 32A in the axial direction.
  • the axial length between the inner corner of the protrusion 41C and the second outer inclined surface 32D of the drive pulley 32A is set to, for example, the same length as the axial length of the second outer gap L22 shown in FIG. 5.
  • the third configuration pattern is a mode in which the inner diameter D1 of the protrusion 41C and the outer diameter D2 of the drive pulley 32A satisfy the following relational expression (3).
  • the outer diameter D2 is the outermost diameter of the drive pulley 32A.
  • the outermost diameter of the drive pulley 32B is the outer diameter of the flange portion 32C.
  • the output shaft 44 and the drive pulley 32A are assembled, for example, so that the second end of the drive pulley 32A is maintained inserted inside the protrusion 41C.
  • the inner peripheral surface of the protrusion 41C and the outer peripheral surface of the drive pulley 32A face each other radially. That is, a radial gap is formed between the inner peripheral surface of the protrusion 41C and the outer peripheral surface of the drive pulley 32A.
  • the radial gap provides an entry path for foreign matter such as wear powder from the belt 32B.
  • the radial length of the radial gap between the inner circumferential surface of the protrusion 41C and the outer circumferential surface of the drive pulley 32A may be set to, for example, the same length as the axial length of the second outer gap L22 in the second configuration pattern shown in FIG. 5.
  • the radial length of the radial gap between the inner circumferential surface of the protrusion 41C and the outer circumferential surface of the drive pulley 32A may also be set to a length shorter than the axial length of the second outer gap L22 in the second configuration pattern. In this case, the entry path of foreign matter in the third configuration pattern is even narrower than the entry path of foreign matter in the second configuration pattern.
  • the second end of the drive pulley 32A may not be inserted inside the protrusion 41C.
  • the first bearing 46 may be a sealed bearing.
  • the first bearing 46 has an inner ring 46A, an outer ring 46B, and a plurality of balls 46C.
  • the inner peripheral surface of the inner ring 46A is fitted to the outer peripheral surface of the output shaft 44.
  • the outer peripheral surface of the outer ring 46B is fitted to the inner peripheral surface of the first bearing support portion 41A of the motor case 41.
  • the balls 46C are held between the inner ring 46A and the outer ring 46B.
  • the balls 46C roll between the inner ring 46A and the outer ring 46B as the output shaft 44 rotates.
  • the first bearing 46 has a seal member 46D.
  • the seal member 46D is an annular plate made of rubber.
  • the seal member 46D is attached to a first end of the first bearing 46.
  • the first end is the end of the first bearing 46 that is closer to the protrusion 41C in the axial direction.
  • the gap between the inner ring 46A and the outer ring 46B is open in the axial direction.
  • the seal member 46D seals the axial opening in the gap between the inner ring 46A and the outer ring 46B.
  • the seal member 46D is maintained in contact with the first end of the inner ring 46A and the first end of the outer ring 46B.
  • the inner ring 46A slides and rotates relative to the seal member 46D.
  • the seal member 46D is not attached to the second end of the first bearing 46.
  • the second end is the end opposite the first end, and is the end of the first bearing 46 farther from the protrusion 41C in the axial direction.
  • the seal member 46D may be attached to the second end of the first bearing 46.
  • the first bearing 46 has two O-rings 46E.
  • the O-rings 46E are made of rubber.
  • the O-rings 46E are endless and circular.
  • Two annular grooves 46F are provided on the outer peripheral surface of the outer ring 46B.
  • the two annular grooves 46F are arranged with a gap in the axial direction.
  • An O-ring 46E is attached to each of the two annular grooves 46F.
  • the present embodiment provides the following actions and effects.
  • the motor case 41 has a protrusion 41C.
  • the protrusion 41C is provided on the outer surface of the end wall of the motor case 41 so as to surround the first through hole 41B.
  • the protrusion 41C extends axially outward from the outer surface of the end wall of the motor case 41.
  • the axial gap L1 between the tip surface of the protrusion 41C and the second end surface of the drive pulley 32A is narrower than the axial gap between the outer surface of the end wall of the motor case 41 and the second end surface of the drive pulley 32A.
  • the intrusion path of foreign matter can be narrowed in the axial direction. Therefore, foreign matter is less likely to intrude into the inside of the first bearing 46 of the motor 31. By reducing the risk of foreign matter intrusion into the first bearing 46, the reliability of the operation of the first bearing 46 and therefore the steering mechanism 11 can be improved.
  • the foreign matter includes wear powder of the belt 32B or grease.
  • the inner diameter D1 of the protrusion 41C is smaller than the outer diameter D2 of the drive pulley 32A.
  • the tip surface of the protrusion 41C faces the second end surface of the drive pulley 32A in the axial direction. Therefore, when the drive pulley 32A is assembled to the output shaft 44, the tip surface of the protrusion 41C and the second end surface of the drive pulley 32A may come into contact with each other in the axial direction due to variations in the axial assembly tolerance.
  • a first inner gap L11 is provided between the tip surface of the protrusion 41C and the second end surface of the drive pulley 32A.
  • the first inner gap L11 has an axial length determined from the viewpoint of absorbing the axial assembly tolerance of the drive pulley 32A relative to the output shaft 44.
  • the inner diameter D1 of the protrusion 41C is the same as the outer diameter D2 of the drive pulley 32A.
  • the inner corner where the inner peripheral surface of the protrusion 41C and the tip surface of the protrusion 41C intersect faces the outer corner where the second outer inclined surface 32D and the outer peripheral surface of the flange portion 32C intersect in the axial direction. Therefore, when assembling the drive pulley 32A to the output shaft 44, there is a risk that the inner corner of the protrusion 41C and the outer corner of the drive pulley 32A will come into contact with each other in the axial direction due to variations in the axial assembly tolerance.
  • a second outer gap L22 is provided between the inner corner of the protrusion 41C and the outer corner of the drive pulley 32A.
  • the second outer gap L22 has an axial length determined from the viewpoint of absorbing the axial assembly tolerance of the drive pulley 32A relative to the output shaft 44. This makes it possible to prevent axial contact between the inner corner of the protrusion 41C and the outer corner of the drive pulley 32A when combining the output shaft 44 with the drive pulley 32A.
  • the axial length of the second outer gap L22 is set to, for example, the same length as the axial length of the first inner gap L11 in the first configuration pattern shown in FIG. 4.
  • the axial length of the second outer gap L22 is shorter than the axial length of the first outer gap L12 in the first configuration pattern. Therefore, with respect to the first configuration pattern, the tip surface of the protrusion 41C can be brought axially closer to the second end surface of the drive pulley 32A by the difference between the axial lengths of the first outer gap L12 and the second outer gap L22. That is, the axial length of the second inner gap L21 is shorter than the axial length of the first inner gap L11 in the first configuration pattern.
  • the intrusion path of foreign matter in the second configuration pattern consisting of the second outer gap L22 and the second inner gap L21 is narrower in the axial direction than the intrusion path of foreign matter in the first configuration pattern consisting of the first outer gap L12 and the first inner gap L11. This makes it possible to further prevent foreign matter, such as wear powder from the belt 32B, from entering the inside of the first bearing 46.
  • the second configuration pattern includes a case where the inner diameter D1 of the protrusion 41C is slightly smaller than the outer diameter D2 of the drive pulley 32A.
  • the inner corner of the protrusion 41C faces the second outer inclined surface 32D of the drive pulley 32A in the axial direction.
  • the axial length between the inner corner of the protrusion 41C and the second outer inclined surface 32D of the drive pulley 32A is set to, for example, the same length as the axial length of the second outer gap L22 shown in FIG. 5. This provides the same effects as those described in sections (4) and (5) above.
  • the inner diameter D1 of the protrusion 41C is larger than the outer diameter D2 of the drive pulley 32A.
  • the second end of the drive pulley 32A can be inserted inside the protrusion 41C. Therefore, when combining the drive pulley 32A with the output shaft 44, it is possible to prevent the tip surface of the protrusion 41C and the drive pulley 32A from coming into contact with each other in the axial direction due to variations in assembly tolerances in the axial direction.
  • the output shaft 44 and the drive pulley 32A can be assembled with the second end of the drive pulley 32A inserted inside the protrusion 41C.
  • the radial gap between the inner peripheral surface of the protrusion 41C and the outer peripheral surface of the drive pulley 32A becomes a path for foreign matter such as wear powder of the belt 32B to enter.
  • the radial length of the radial gap can be set to a length shorter than the axial length of the second outer gap L22 in the second configuration pattern shown in FIG. 5, for example. Therefore, the path for foreign matter to enter in the third configuration pattern can be made even narrower than the path for foreign matter to enter in the second configuration pattern. Therefore, it is possible to further suppress the entry of foreign matter such as wear powder of the belt 32B into the inside of the first bearing 46.
  • the first bearing 46 has a seal member 46D.
  • the seal member 46D seals only the axial opening in the gap between the inner ring 46A and the outer ring 46B, which is the axial opening closer to the protrusion 41C. Foreign matter such as wear powder from the belt 32B passes through the inside of the protrusion 41C and reaches the first bearing 46. Therefore, even if a foreign matter reaches the first bearing 46, the foreign matter can be prevented from entering the inside of the first bearing 46.
  • the seal member 46D is provided, for example, in contact with the axial ends of the inner ring 46A and the outer ring 46B. This makes it possible to reduce the friction torque caused by contact between the inner ring 46 and the seal member 46D, compared to a case in which a seal member 46D is provided at each end of the inner ring 46A and the outer ring 46B in the axial direction.
  • the first bearing 46 has an O-ring 46E.
  • the O-ring 46E is attached to the outer peripheral surface of the outer ring 46B.
  • the O-ring 46E is compressed radially inward. This seals the gap between the outer peripheral surface of the outer ring 46B and the inner peripheral surface of the first bearing support portion 41A. Therefore, even if a foreign object reaches the first bearing 46, the foreign object can be prevented from entering the inside of the motor case 41 through the gap between the outer peripheral surface of the outer ring 46B and the inner peripheral surface of the first bearing support portion 41A.
  • the large diameter portion 44A of the output shaft 44 has a restricting surface 44B.
  • the restricting surface 44B faces the inner ring of the second bearing 47 in the axial direction.
  • the second gap ⁇ 2 between the restricting surface 44A and the inner ring of the second bearing 47 is set to be narrower than the first gap ⁇ 1 between the magnetic flux generator 48 and the rotation angle sensor 48. Therefore, when the output shaft 44 moves axially toward the rotation angle sensor 52C due to an external force, the restricting surface 44B comes into contact with the inner ring of the second bearing 4 before the magnetic flux generator 48 comes into contact with the rotation angle sensor 52C. Therefore, even if the output shaft 44 moves axially due to an external force, the magnetic flux generator 48 can be prevented from coming into contact with the rotation angle sensor 52C in the axial direction.
  • the press-fit position of the second bearing 47 relative to the output shaft 44 for example, to a position where the inner ring of the second bearing 47 contacts the regulating surface 44A in the axial direction.
  • an overshoot load may be applied to the second bearing 47.
  • the overshoot load is an overload that acts in a direction that presses the second bearing 47, which is in contact with the regulating surface 44B, further into the output shaft 44.
  • the overshoot load presses the inner ring of the second bearing 47 further against the regulating surface 33B. This may cause damage to the second bearing 47.
  • a second gap ⁇ 2 is provided between the regulating surface 44A and the inner ring of the second bearing 47. Therefore, even if the first end of the output shaft 44 hits an object, the restricting surface 44B is prevented from coming into axial contact with the inner ring of the 22nd bearing 47. This prevents an overshoot load from being applied to the second bearing 47. In addition, damage to the second bearing 47 can be prevented.
  • the outer peripheral surface of the portion of the belt 32B wound around the drive pulley 32A is located radially outward of the first through hole 41B. This makes it easier for foreign matter such as wear powder generated by the belt 32B to scatter radially outward. This makes it possible to prevent foreign matter from entering the inside of the protrusion 41C.
  • the drive pulley 32A has a flange portion 32C.
  • the flange portion 32C is provided around the entire outer circumferential surface of the axial end of the drive pulley 32A that is closer to the end wall of the motor case 41.
  • the outer circumferential surface of the flange portion 32C is located radially inward relative to the outer circumferential surface of the portion of the belt 32B wound around the drive pulley 32A.
  • the outer circumferential surface of the flange portion 32C is located radially outward relative to the inner circumferential surface of the portion of the belt 32B wound around the drive pulley 32A. Therefore, the movement of the belt 32B in the direction from the first end to the second end of the drive pulley 32A can be appropriately restricted by the flange portion 32C.
  • the large diameter portion 44B may be provided, for example, only in a portion of the output shaft 44 between the rotor core 45A and the second bearing 47. In this case, the rotor core 45A is not attached to the outer circumferential surface of the large diameter portion 44B.
  • the large diameter portion 44B and the rotor core 45A are arranged side by side in the axial direction.
  • the large diameter portion 44B does not have to be formed integrally with the output shaft 44.
  • the large diameter portion 44B may be a separate member from the output shaft 44.
  • the tip surface of the protrusion 41C faces the second end surface of the drive pulley 32A in the axial direction. Therefore, instead of setting the second gap ⁇ 2 smaller than the first gap in the stopper structure of the output shaft 44, the following may be done. That is, the axial gap between the tip surface of the protrusion 41C and the second end surface of the drive pulley 32A is set to be narrower than the first gap ⁇ 1.
  • the transmission mechanism 32 may be a worm reducer.
  • the worm reducer is a mechanism that combines a worm and a worm wheel.
  • the worm is connected to the tip of the output shaft 44 via a joint.
  • the joint is a power transmission member.
  • the conversion mechanism 33 may also be a rack-and-pinion mechanism.
  • the rack-and-pinion mechanism is a mechanism that combines a pinion shaft and a rack shaft.
  • the steering shaft 22 also serves as the rack shaft. In this case, wear powder from the worm or worm wheel, or grease applied to the worm or worm wheel, may enter the inside of the motor case 41 through the first through hole 41B.
  • the tip surface of the protrusion 41C faces, for example, the joint in the axial direction.
  • the joint is a part that connects the worm and the output shaft 44. Therefore, instead of setting the second gap ⁇ 2 smaller than the first gap in the stopper structure of the output shaft 44, the following may be done. That is, the axial gap between the tip surface of the protrusion 41C and the joint is set to be narrower than the first gap ⁇ 1. In this way, when the output shaft 44 moves axially toward the rotation angle sensor 52C due to an external force, the joint comes into axial contact with the tip surface of the protrusion 41C before the magnetic flux generator 48 comes into contact with the rotation angle sensor 52C. Therefore, even if the output shaft 44 moves axially due to an external force, it is possible to prevent the magnetic flux generator 48 from coming into axial contact with the rotation angle sensor 52C.
  • the motor 31 may be configured to omit the stopper structure of the output shaft 44.
  • the output shaft 44 does not need to have a large diameter portion 44A. There is no need to adjust the size relationship between the first gap ⁇ 1 and the second gap ⁇ 2.
  • the drive pulley 32A may be configured not to have the second outer inclined surface 32D. This can prevent foreign matter from entering the inside of the first bearing 46, compared to when the motor case 41 does not have the protrusion 41C.
  • the motor 31 may be configured without the protrusion 41C.
  • the inner diameter of the first through hole 41B is set to be the same as the outer diameter D2 of the drive pulley 32A.
  • the inner corner where the inner peripheral surface of the first through hole 41B intersects with the outer surface of the end wall of the motor case 41 is provided to be separated from the outer corner where the second outer inclined surface 32D of the drive pulley 32A intersects with the outer peripheral surface of the drive pulley 32A by a predetermined distance in the axial direction.
  • the predetermined distance is, for example, the same length as the second outer gap L22 shown in FIG. 5 above. Even in this case, it is possible to obtain the same effects as those described in sections (3), (4), and (5) above.
  • the inner diameter of the first through hole 41B is set to be larger than the outer diameter D2 of the drive pulley 32A.
  • the second end of the drive pulley 32A is maintained in a state inserted inside the first through hole 41B, for example.
  • the second end of the drive pulley 32A is the axial end closer to the end wall of the motor case 41.
  • the inner peripheral surface of the first through hole 41B is spaced apart from the outer peripheral surface of the drive pulley 32A by a predetermined distance in the radial direction.
  • the predetermined distance may be, for example, the same length as the second outer gap L22 shown in FIG. 5 above, or may be shorter than the second outer gap L22. Even in this way, the same effects as those described in (6) and (7) above can be obtained.
  • the second end of the drive pulley 32A may not be inserted inside the first through hole 41B.
  • the steering mechanism 11 is an example of an electric drive device, but is not limited to this.
  • the electric drive device includes any mechanical device having a motor 31 and a transmission mechanism 32.
  • the term “cylinder” or “cylindrical” may refer to any structure having a peripheral wall.
  • the term “cylinder” or “cylindrical” may refer to any structure having a cross-sectional shape, such as, but not limited to, a circle, an oval, and a polygon with sharp or rounded corners.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)

Abstract

An electric drive device (11) comprises: a motor (31) that is configured to generate drive force that is for driving a drive target (22); and a transmission mechanism (32) that is configured to transmit the drive force of the motor (31) to the drive target (22). The motor (31) has: a motor case (41) that includes an end wall that has a through hole (41B) that passes in the axial direction; and an output shaft (44) that passes through the through hole (41B) in the axial direction so as not to contact the inner circumferential surface of the through hole (41B), the output shaft (44) being supported so as to be capable of rotation relative to the inner circumferential surface of the motor case (41). The transmission mechanism (32) has a cylindrical motive force transmission member (32A) that is connected outside the motor case (41) so as to be capable of integral rotation with the output shaft (44). The motor case (41) has a cylindrical protrusion (41C) that surrounds the through hole (41B) at an outer surface of the end wall.

Description

電動駆動装置Electric drive unit
　本開示は、電動駆動装置に関する。 This disclosure relates to an electric drive device.
　たとえば、特許文献１の操舵装置は、ベルト伝動機構を有する。ベルト伝動機構は、モータのトルクを、転舵シャフトに伝達するように構成される。転舵シャフトは、ボールナットを有する。ベルト伝動機構は、モータの出力軸に設けられる駆動プーリと、転舵シャフトのボールナットに設けられる従動プーリと、駆動プーリと従動プーリとに巻き掛けられるベルトと、を有する。 For example, the steering device of Patent Document 1 has a belt transmission mechanism. The belt transmission mechanism is configured to transmit the torque of the motor to the steered shaft. The steered shaft has a ball nut. The belt transmission mechanism has a drive pulley provided on the output shaft of the motor, a driven pulley provided on the ball nut of the steered shaft, and a belt wound around the drive pulley and the driven pulley.
　転舵シャフトおよびベルト伝動機構は、ハウジングに収容されている。モータは、ハウジングの外部に取り付けられている。モータの出力軸は、駆動軸を介して駆動プーリに連結されている。駆動軸は、軸受を介して、ハウジングに対して回転可能に支持されている。軸受は、軸方向において、駆動プーリとモータの出力軸との間に位置している。 The steering shaft and belt transmission mechanism are housed in a housing. The motor is attached to the outside of the housing. The output shaft of the motor is connected to the drive pulley via a drive shaft. The drive shaft is rotatably supported relative to the housing via a bearing. The bearing is located axially between the drive pulley and the output shaft of the motor.
特開２０２１－１５４９６５号公報JP 2021-154965 A
　ベルト伝動機構を有する操舵装置には、つぎのような懸念がある。すなわち、ベルト伝動機構の長期の使用に伴い、たとえばベルトが摩耗することにより、摩耗粉が発生することがある。摩耗粉がモータの出力軸を支持する軸受の内部に侵入することにより、軸受の円滑な動作が阻害されるおそれがある。これは、モータおよび伝動機構を有する機械装置の全般についていえることである。 Steering devices with belt transmission mechanisms have the following concerns. Namely, over time, the belt transmission mechanism may wear out and generate wear powder. If the wear powder gets inside the bearings that support the motor's output shaft, it may hinder the smooth operation of the bearings. This is true for all mechanical devices that have motors and transmission mechanisms.
　本開示の一態様にかかる電動駆動装置は、駆動対象を駆動させるための駆動力を発生するように構成されるモータと、前記モータの駆動力を前記駆動対象に伝達するように構成される伝動機構と、を備える。前記モータは、軸方向に貫通する貫通孔を有する端壁を含むモータケースと、前記貫通孔の内周面に非接触状態で前記貫通孔を軸方向に貫通する出力軸であって、前記モータケースの内周面に対して回転可能に支持される出力軸と、を有する。前記伝動機構は、前記モータケースの外側において、前記出力軸に対して一体的に回転可能に連結される筒状の動力伝達部材を有する。前記モータケースは、前記端壁の外面において、前記貫通孔の周囲を囲む筒状の突部を有する。 An electric drive device according to one aspect of the present disclosure includes a motor configured to generate a driving force for driving a driven object, and a transmission mechanism configured to transmit the driving force of the motor to the driven object. The motor has a motor case including an end wall having a through hole penetrating in the axial direction, and an output shaft penetrating the through hole in the axial direction without contacting the inner peripheral surface of the through hole and supported rotatably on the inner peripheral surface of the motor case. The transmission mechanism has a cylindrical power transmission member connected to the output shaft rotatably and integrally on the outside of the motor case. The motor case has a cylindrical protrusion on the outer surface of the end wall surrounding the periphery of the through hole.
電動駆動装置の一実施の形態にかかる転舵機構の構成図である。1 is a configuration diagram of a steering mechanism according to an embodiment of an electric drive device; 図１のモータの断面図である。FIG. 2 is a cross-sectional view of the motor of FIG. 1 . 図２のモータの出力軸と駆動プーリとの連結部分の断面図である。3 is a cross-sectional view of a connection portion between an output shaft and a drive pulley of the motor in FIG. 2. 図２のモータにおける異物の侵入抑制構造の第１の構成パターンを示す断面図である。3 is a cross-sectional view showing a first configuration pattern of a foreign object intrusion prevention structure in the motor of FIG. 2. 図２のモータにおける異物の侵入抑制構造の第２の構成パターンを示す断面図である。3 is a cross-sectional view showing a second configuration pattern of the foreign object intrusion prevention structure in the motor of FIG. 2. 図２のモータの第１の軸受の断面図である。FIG. 3 is a cross-sectional view of a first bearing of the motor of FIG. 2 .
　一実施の形態に係る電動駆動装置を説明する。
　図１に示すように、車両の操舵装置は、転舵機構１１を有している。転舵機構１１は、ステアリングホイールの操舵に応じて、車両の転舵輪１２を転舵させる機構部分である。 An electric drive device according to one embodiment will be described.
1, the steering device of a vehicle has a steering mechanism 11. The steering mechanism 11 is a mechanical part that steers steered wheels 12 of the vehicle in response to the steering of a steering wheel.
　転舵機構１１は、ピニオンシャフト２１と、転舵シャフト２２と、ハウジング２３と、を有している。ハウジング２３は、ピニオンシャフト２１を回転可能に支持している。また、ハウジング２３は、転舵シャフト２２を軸方向に往復動可能に収容している。ピニオンシャフト２１は、転舵シャフト２２に対して交わるように設けられている。ピニオンシャフト２１のピニオン歯２１ａは、転舵シャフト２２のラック歯２２ａと噛み合っている。転舵シャフト２２の両端は、ラックエンド２４およびタイロッド２５を介して、転舵輪１２に連結されている。 The steering mechanism 11 has a pinion shaft 21, a steered shaft 22, and a housing 23. The housing 23 rotatably supports the pinion shaft 21. The housing 23 also accommodates the steered shaft 22 so that it can reciprocate in the axial direction. The pinion shaft 21 is arranged to intersect with the steered shaft 22. The pinion teeth 21a of the pinion shaft 21 mesh with the rack teeth 22a of the steered shaft 22. Both ends of the steered shaft 22 are connected to the steered wheels 12 via rack ends 24 and tie rods 25.
　操舵装置は、ステアバイワイヤ式の操舵装置、または電動パワーステアリング装置である。操舵装置がステアバイワイヤ式の操舵装置である場合、ピニオンシャフト２１は、ステアリングホイールに対して機械的に連結されない。操舵装置が電動パワーステアリング装置である場合、ピニオンシャフト２１は、ステアリングシャフトを介して、ステアリングホイールに対して機械的に連結される。 The steering device is a steer-by-wire type steering device or an electric power steering device. If the steering device is a steer-by-wire type steering device, the pinion shaft 21 is not mechanically connected to the steering wheel. If the steering device is an electric power steering device, the pinion shaft 21 is mechanically connected to the steering wheel via a steering shaft.
　転舵機構１１は、モータ３１と、伝動機構３２と、変換機構３３とを備えている。モータ３１は、電動機であって、転舵シャフト２２に付与される転舵力の発生源である。転舵力は、転舵輪１２を転舵させるための力である。モータ３１は、たとえば三相のブラシレスモータである。伝動機構３２は、たとえばベルト伝動機構である。伝動機構３２は、モータ３１の回転を変換機構３３に伝達する。変換機構３３は、たとえばボールねじ機構である。変換機構３３は、伝動機構３２を介して伝達される回転を、転舵シャフト２２の軸方向の運動に変換する。転舵シャフト２２が軸方向に移動することによって、転舵輪１２の転舵角θｗが変更される。転舵シャフト２２は、モータ３１の駆動対象である。 The steering mechanism 11 includes a motor 31, a transmission mechanism 32, and a conversion mechanism 33. The motor 31 is an electric motor and is a source of a steering force applied to the steering shaft 22. The steering force is a force for steering the steered wheels 12. The motor 31 is, for example, a three-phase brushless motor. The transmission mechanism 32 is, for example, a belt transmission mechanism. The transmission mechanism 32 transmits the rotation of the motor 31 to the conversion mechanism 33. The conversion mechanism 33 is, for example, a ball screw mechanism. The conversion mechanism 33 converts the rotation transmitted via the transmission mechanism 32 into axial motion of the steered shaft 22. The steered angle θ w of the steered wheels 12 is changed by the axial movement of the steered shaft 22. The steered shaft 22 is a drive target of the motor 31.
　操舵装置がステアバイワイヤ式の操舵装置である場合、モータ３１は、転舵モータとして機能する。転舵モータは、転舵輪１２を転舵させるための力である転舵力を発生する。操舵装置が電動パワーステアリング装置である場合、モータ３１は、アシストモータとして機能する。アシストモータは、ステアリングホイールの操作を補助するための力であるアシスト力を発生する。 If the steering device is a steer-by-wire type steering device, the motor 31 functions as a steering motor. The steering motor generates a steering force for steering the steered wheels 12. If the steering device is an electric power steering device, the motor 31 functions as an assist motor. The assist motor generates an assist force for assisting the operation of the steering wheel.
　なお、転舵機構１１は、電動駆動装置に相当する。電動駆動装置は、電気エネルギを力学的エネルギに変換する電動機の駆動力によって、駆動対象を駆動させる装置である。
　＜モータ３１の構成＞
　つぎに、モータ３１の構成について詳細に説明する。 The steering mechanism 11 corresponds to an electric drive device. The electric drive device drives a driven object by the driving force of an electric motor that converts electric energy into mechanical energy.
<Configuration of Motor 31>
Next, the configuration of the motor 31 will be described in detail.
　図２に示すように、モータ３１は、モータ本体４０と、制御装置５０とを有している。モータ本体４０と制御装置５０とは一体化されている。
　モータ本体４０は、モータケース４１を有している。モータケース４１は、円形の断面形状を有する筒状である。モータケース４１の第１の端部は、端壁によって塞がれている。モータケース４１の第２の端部は、軸方向に開口している。モータケース４１は、第１の軸受支持部４１Ａを有している。第１の軸受支持部４１Ａは、モータケース４１の端壁の内面に設けられた穴であって、円形の断面形状を有している。第１の軸受支持部４１Ａは、第１の貫通孔４１Ｂを介して、モータケース４１の外側に軸方向に開口している。 2, the motor 31 has a motor body 40 and a control device 50. The motor body 40 and the control device 50 are integrated together.
The motor body 40 has a motor case 41. The motor case 41 is cylindrical and has a circular cross-sectional shape. A first end of the motor case 41 is closed by an end wall. A second end of the motor case 41 is open in the axial direction. The motor case 41 has a first bearing support portion 41A. The first bearing support portion 41A is a hole provided on the inner surface of the end wall of the motor case 41 and has a circular cross-sectional shape. The first bearing support portion 41A is open in the axial direction to the outside of the motor case 41 via a first through hole 41B.
　モータ本体４０は、蓋４２を有している。蓋４２は、モータケース４１の第２の端部に嵌め込まれることによって、第２の端部の開口を塞いでいる。蓋４２は、第２の軸受支持部４２Ａと、磁石収容部４２Ｂとを有している。第２の軸受支持部４２Ａは、モータケース４１の内側に軸方向に開口する穴であって、円形の断面形状を有している。磁石収容部４２Ａは、蓋４２の外側に軸方向に開口する穴であって、円形の断面形状を有している。第１の軸受支持部４２Ａの内部と磁石収容部４２Ｂの内部とは、第２の貫通孔４２Ｃを介して、互いに軸方向に連通している。 The motor body 40 has a lid 42. The lid 42 is fitted into the second end of the motor case 41 to close the opening of the second end. The lid 42 has a second bearing support portion 42A and a magnet accommodating portion 42B. The second bearing support portion 42A is a hole that opens in the axial direction on the inside of the motor case 41 and has a circular cross-sectional shape. The magnet accommodating portion 42A is a hole that opens in the axial direction on the outside of the lid 42 and has a circular cross-sectional shape. The interior of the first bearing support portion 42A and the interior of the magnet accommodating portion 42B are axially connected to each other via a second through-hole 42C.
　モータ本体４０は、ステータ４３と、出力軸４４と、ロータ４５と、第１の軸受４６と、第２の軸受と、磁束発生体４８とを有している。ステータ４３は、ステータコア４３Ａと、ステータコア４３Ａに設けられたステータコイル４３Ｂとを有している。ステータコア４３Ａは、円形の断面形状を有する筒状である。ステータコア４３Ａは、モータケース４１の内周面に対して嵌められた状態で固定されている。 The motor body 40 has a stator 43, an output shaft 44, a rotor 45, a first bearing 46, a second bearing, and a magnetic flux generator 48. The stator 43 has a stator core 43A and a stator coil 43B provided in the stator core 43A. The stator core 43A is cylindrical with a circular cross-sectional shape. The stator core 43A is fixed in a fitted state against the inner circumferential surface of the motor case 41.
　出力軸４４は、第１の軸受４６と第２の軸受４７とを介して、モータケース４１に対して回転可能に支持されている。第１の軸受４６は、モータケース４１の第１の軸受支持部４１Ａに装着されている。第２の軸受４７は、蓋４２の第２の軸受支持部４２Ａに装着されている。出力軸４４は、モータケース４１を軸方向に貫通している。出力軸４４の第１の端部は、モータケース４１の第１の貫通孔４１Ｂを介して、モータケース４１の外側に軸方向に突出している。出力軸４４の第２の端部は、蓋４２の第２の貫通孔４２Ｃを介して、磁石収容部４２Ｂの内部に位置している。 The output shaft 44 is rotatably supported relative to the motor case 41 via a first bearing 46 and a second bearing 47. The first bearing 46 is attached to a first bearing support portion 41A of the motor case 41. The second bearing 47 is attached to a second bearing support portion 42A of the lid 42. The output shaft 44 passes through the motor case 41 in the axial direction. The first end of the output shaft 44 protrudes axially to the outside of the motor case 41 via a first through hole 41B of the motor case 41. The second end of the output shaft 44 is located inside the magnet storage portion 42B via a second through hole 42C of the lid 42.
　ロータ４５は、ステータ４３の内側に位置している。ロータ４５は、ロータコア４５Ａと、永久磁石４５Ｂとを有している。ロータコア４５Ａは、円形の断面形状を有する筒状であって、出力軸４４の外周面に固定されている。永久磁石４５Ｂは、円形の断面形状を有する筒状であって、ロータコア４５Ａの外周面に固定されている。ロータ４５は、ステータ４３の内周面に対して、非接触状態で回転可能である。 The rotor 45 is located inside the stator 43. The rotor 45 has a rotor core 45A and a permanent magnet 45B. The rotor core 45A is cylindrical with a circular cross-sectional shape and is fixed to the outer circumferential surface of the output shaft 44. The permanent magnet 45B is cylindrical with a circular cross-sectional shape and is fixed to the outer circumferential surface of the rotor core 45A. The rotor 45 can rotate without contacting the inner circumferential surface of the stator 43.
　磁束発生体４８は、出力軸４４の第２の端部に設けられている。磁束発生体４８は、磁石４８Ａと、ホルダ４８Ｂと、スペーサ４８Ｃとを有している。磁石４８Ａは、円柱状である。磁石４８Ａは、いわゆる２極磁石である。磁石４８Ａの直径方向の半分がＮ極に、残りの半分がＳ極に着磁されている。磁石４８Ａは、ホルダ４８Ｂを介して、出力軸４４に取り付けられている。 The magnetic flux generator 48 is provided at the second end of the output shaft 44. The magnetic flux generator 48 has a magnet 48A, a holder 48B, and a spacer 48C. The magnet 48A is cylindrical. The magnet 48A is a so-called two-pole magnet. Half of the diameter of the magnet 48A is magnetized to the north pole, and the remaining half is magnetized to the south pole. The magnet 48A is attached to the output shaft 44 via the holder 48B.
　ホルダ４８Ｂは、非磁性材料製である。非磁性材料は、合成樹脂であってもよいし、アルミニウム合金または亜鉛合金であってもよい。ホルダ４８Ｂは、円形の断面形状を有する筒状である。ホルダ４８Ｂの第１の端部は、軸方向に開口している。ホルダ４８Ｂの第２の端部は、端壁により塞がれている。第２の端部は、第１の端部と軸方向に反対側のホルダ４８Ｂの端部である。ホルダ４８Ｂは、径方向外側に張り出すフランジ部を有する。フランジ部は、ホルダ４８Ｂの第２の端部の外周面に設けられている。ホルダ４８Ｂのフランジ部を含む第２の端面は、軸方向に対して直交する平面である。 The holder 48B is made of a non-magnetic material. The non-magnetic material may be a synthetic resin, an aluminum alloy, or a zinc alloy. The holder 48B is cylindrical with a circular cross-sectional shape. A first end of the holder 48B is open in the axial direction. A second end of the holder 48B is closed by an end wall. The second end is the end of the holder 48B opposite the first end in the axial direction. The holder 48B has a flange portion that protrudes radially outward. The flange portion is provided on the outer peripheral surface of the second end of the holder 48B. The second end face including the flange portion of the holder 48B is a plane perpendicular to the axial direction.
　磁石４８Ａは、ホルダ４８Ｂの内部に嵌め込まれている。磁石４８Ａとホルダ４８Ｂの端壁とは、互いに軸方向に接触した状態に維持されている。ホルダ４８Ｂの第１の端部は、出力軸４４の第２の端部の外周面に嵌った状態で固定されている。スペーサ４８Ｃは、ホルダ４８Ｂと同様に、非磁性材料製である。スペーサ４８Ｃは、円柱状であって、磁石４８Ａと出力軸４４の第２の端部との間に介在されている。 The magnet 48A is fitted inside the holder 48B. The magnet 48A and the end wall of the holder 48B are maintained in axial contact with each other. The first end of the holder 48B is fixed in a fitted state to the outer circumferential surface of the second end of the output shaft 44. The spacer 48C, like the holder 48B, is made of a non-magnetic material. The spacer 48C is cylindrical and is interposed between the magnet 48A and the second end of the output shaft 44.
　制御装置５０は、カバー５１と、基板５２とを有している。カバー５１は、たとえば、円形の断面形状を有する筒状である。カバー５１の第１の端部は、軸方向に開口している。カバー５１の第２の端部は、端壁により塞がれている。第２の端部は、第１の端部と軸方向に反対側のカバー５１の端部である。カバー５１は、開口をモータケース４１へ向けた状態で、モータケース４１の第２の端部に固定されている。 The control device 50 has a cover 51 and a substrate 52. The cover 51 is, for example, cylindrical with a circular cross-sectional shape. A first end of the cover 51 is open in the axial direction. A second end of the cover 51 is closed by an end wall. The second end is the end of the cover 51 axially opposite the first end. The cover 51 is fixed to the second end of the motor case 41 with the opening facing the motor case 41.
　基板５２は、カバー５１の内部に収容されている。基板５２は、出力軸４４の軸方向に対して直交するように、カバー５１に固定されている。基板５２は、磁束発生体４８と軸方向に対向している。基板３１は、ＭＰＵ（micro processing unit）５２Ａと、インバータ回路５２Ｂと、回転角センサ５２Ｃとを有している。 The board 52 is housed inside the cover 51. The board 52 is fixed to the cover 51 so as to be perpendicular to the axial direction of the output shaft 44. The board 52 faces the magnetic flux generator 48 in the axial direction. The board 31 has an MPU (micro processing unit) 52A, an inverter circuit 52B, and a rotation angle sensor 52C.
　ＭＰＵ５２Ａおよび回転角センサ５２Ｃは、たとえば、基板５２の第１の面に設けられている。第１の面は、モータ本体４０に軸方向に対向する基板５２の面である。回転角センサ５２Ｃは、磁束発生体４８に軸方向に対向している。磁束発生体４８が発生する磁界は、回転角センサ５２Ｃに付与される。インバータ回路５２Ｂは、たとえば、基板５２の第２の面に設けられている。第２の面は、第１の面と反対側の基板５２の面である。 The MPU 52A and the rotation angle sensor 52C are provided, for example, on a first surface of the substrate 52. The first surface is the surface of the substrate 52 that faces the motor body 40 in the axial direction. The rotation angle sensor 52C faces the magnetic flux generator 48 in the axial direction. The magnetic field generated by the magnetic flux generator 48 is applied to the rotation angle sensor 52C. The inverter circuit 52B is provided, for example, on a second surface of the substrate 52. The second surface is the surface of the substrate 52 opposite the first surface.
　インバータ回路５２Ｂは、複数のスイッチング素子を有する。ＭＰＵ５２Ａにより生成されるスイッチング指令に基づき、スイッチング素子がスイッチング動作を行うことにより三相の交流電力が生成される。交流電力は、図示しない給電経路を介して、三相各相のステータコイル４３Ｂに供給される。 The inverter circuit 52B has multiple switching elements. Based on switching commands generated by the MPU 52A, the switching elements perform switching operations to generate three-phase AC power. The AC power is supplied to the stator coils 43B of each of the three phases via power supply paths (not shown).
　回転角センサ５２Ｃは、磁気センサであって、たとえばＭＲセンサ（磁気抵抗効果センサ）である。回転角センサ５２Ｃに付与される磁界の方向は、ロータ４５の回転角に応じて変化する。ロータ４５の回転角は、出力軸４４の回転角でもある。回転角センサ５２Ｃは、磁界の方向の変化に応じた電気信号を生成する。磁束発生体４８は、回転角センサ５２Ｃの検出対象である。 The rotation angle sensor 52C is a magnetic sensor, for example an MR sensor (magnetoresistive effect sensor). The direction of the magnetic field applied to the rotation angle sensor 52C changes according to the rotation angle of the rotor 45. The rotation angle of the rotor 45 is also the rotation angle of the output shaft 44. The rotation angle sensor 52C generates an electrical signal according to the change in the direction of the magnetic field. The magnetic flux generator 48 is the detection target of the rotation angle sensor 52C.
　ＭＰＵ５２Ａは、回転角センサ５２が生成する電気信号に基づき、ロータ４５の回転角を演算する。ＭＰＵ５２Ａは、ロータ４５の回転角に基づき、インバータ回路５２Ｂに対するスイッチング指令を生成する。スイッチング指令は、モータ本体４０の駆動を制御するためのモータ制御信号である。 The MPU 52A calculates the rotation angle of the rotor 45 based on the electrical signal generated by the rotation angle sensor 52. The MPU 52A generates a switching command for the inverter circuit 52B based on the rotation angle of the rotor 45. The switching command is a motor control signal for controlling the drive of the motor main body 40.
　＜出力軸４４の位置ずれについて＞
　モータ３１には、つぎのような懸念がある。たとえばモータ３１の組み立て時、出力時４４の第１の端部が何らかの物体にぶつかることにより、出力軸４４の第１の端部に外力が作用することが考えられる。外力は、たとえば、出力軸４４の第１の端部から第２の端部へ向かう方向の力である。このため、出力軸４４の第１の端部に外力が作用することによって、出力軸４４が、第１の軸受４６の内輪および第２の軸受４７の内輪に対して、軸方向に移動するおそれがある。これにより、出力軸４４の第２の端部に設けられた磁束発生体４８が、回転角センサ５２Ｃに軸方向に接触するおそれがある。そこで、本実施の形態では、モータ３１として、つぎのような構成を採用している。 <Regarding positional deviation of the output shaft 44>
The motor 31 has the following concerns. For example, when assembling the motor 31, it is considered that an external force acts on the first end of the output shaft 44 when the first end of the output shaft 44 hits some object. The external force is, for example, a force in a direction from the first end to the second end of the output shaft 44. Therefore, when an external force acts on the first end of the output shaft 44, the output shaft 44 may move in the axial direction relative to the inner ring of the first bearing 46 and the inner ring of the second bearing 47. As a result, the magnetic flux generator 48 provided on the second end of the output shaft 44 may come into contact with the rotation angle sensor 52C in the axial direction. Therefore, in this embodiment, the following configuration is adopted as the motor 31.
　＜出力軸４４のストッパ構造＞
　図２に示すように、出力軸４４は、大径部４４Ａを有している。大径部４４Ａは、出力軸４４の他の部分よりも大きい外径を有する。大径部４４Ａは、出力軸４４Ａの第１の端部と第２の端部との中間に位置している。大径部４４Ａの外周面には、ロータコア４５Ａが装着されている。大径部４４Ａは、規制面４４Ｂを有している。規制面４４Ｂは、第２の軸受４７の内輪に軸方向に対向する大径部４４Ａの端面である。規制面４４Ｂは、軸方向に直交する方向に広がる平面である。 <Stopper structure of output shaft 44>
As shown in Fig. 2, the output shaft 44 has a large diameter portion 44A. The large diameter portion 44A has an outer diameter larger than other portions of the output shaft 44. The large diameter portion 44A is located midway between the first end and the second end of the output shaft 44A. A rotor core 45A is attached to the outer circumferential surface of the large diameter portion 44A. The large diameter portion 44A has a restricting surface 44B. The restricting surface 44B is an end surface of the large diameter portion 44A that faces the inner ring of the second bearing 47 in the axial direction. The restricting surface 44B is a flat surface that extends in a direction perpendicular to the axial direction.
　磁束発生体４８と回転角センサ４８との間には、軸方向に第１の隙間δ１が形成されている。規制面４４Ａと第２の軸受４７の内輪との間には、軸方向に第２の隙間δ２が形成されている。第１の隙間δ１と第２の隙間δ２とは、つぎの関係式（０）を満たすように設定されている。 A first gap δ1 is formed in the axial direction between the magnetic flux generator 48 and the rotation angle sensor 48. A second gap δ2 is formed in the axial direction between the regulating surface 44A and the inner ring of the second bearing 47. The first gap δ1 and the second gap δ2 are set to satisfy the following relational expression (0).
　δ１＞δ２　…（０）
　第２の隙間δ２が第１の隙間δ１よりも狭い。このため、外力によって、出力軸４４が回転角センサ５２Ｃへ向けて軸方向に移動するとき、磁束発生体４８が回転角センサ５２Ｃに軸方向に接触する前に、規制面４４Ｂが第２の軸受４の内輪に軸方向に接触する。したがって、外力によって、たとえ出力軸４４が軸方向に移動したとしても、磁束発生体４８が回転角センサ５２Ｃに軸方向に接触することが抑制される。 δ1>δ2 ... (0)
The second gap δ2 is narrower than the first gap δ1. Therefore, when the output shaft 44 moves axially toward the rotation angle sensor 52C due to an external force, the regulating surface 44B comes into axial contact with the inner ring of the second bearing 4 before the magnetic flux generator 48 comes into axial contact with the rotation angle sensor 52C. Therefore, even if the output shaft 44 moves axially due to an external force, the magnetic flux generator 48 is prevented from coming into axial contact with the rotation angle sensor 52C.
　＜伝動機構３２の構成＞
　つぎに、伝動機構３２の構成について説明する。
　図３に示すように、伝動機構３２は、駆動プーリ３２Ａ、ベルト３２Ｂ、および従動プーリ（図示略）を有している。出力軸４４の第１の端部は、モータケース４１の外部に突出している。駆動プーリ３２Ａは、円形の断面形状を有する筒状である。駆動プーリ３２Ａは、出力軸４４の第１の端部の外周面に嵌った状態で固定されている。駆動プーリ３２Ａは、第１の端部と、第２の端部とを有している。第１の端部は、軸方向においてモータケース４１に近い側の駆動プーリ３２Ａの端部である。第２の端部は、軸方向においてモータケース４１に近い側の駆動プーリ３２Ａの端部である。従動プーリは、変換機構３３のボールナットの外周面に装着される。ベルト３２Ｂは、たとえば、ゴム製である。ベルト３２Ｂは、無端状であって、駆動プーリ３２Ａと従動プーリとの間に巻き掛けられる。駆動プーリ３２Ａに巻かれているベルト３２Ｂの部分の外周面は、たとえば、第１の貫通孔４１Ｂの径方向外側に位置している。モータ３１のトルクは、駆動プーリ４２Ａ、ベルト３２Ｂ、および従動プーリを介して、変換機構３３のボールナットに伝達される。駆動プーリ３２Ａは、動力伝達部材である。 <Configuration of transmission mechanism 32>
Next, the configuration of the transmission mechanism 32 will be described.
As shown in FIG. 3, the transmission mechanism 32 has a driving pulley 32A, a belt 32B, and a driven pulley (not shown). The first end of the output shaft 44 protrudes outside the motor case 41. The driving pulley 32A is cylindrical with a circular cross-sectional shape. The driving pulley 32A is fixed in a state of being fitted into the outer circumferential surface of the first end of the output shaft 44. The driving pulley 32A has a first end and a second end. The first end is an end of the driving pulley 32A that is closer to the motor case 41 in the axial direction. The second end is an end of the driving pulley 32A that is closer to the motor case 41 in the axial direction. The driven pulley is attached to the outer circumferential surface of a ball nut of the conversion mechanism 33. The belt 32B is made of, for example, rubber. The belt 32B is endless and is wound between the driving pulley 32A and the driven pulley. The outer circumferential surface of the portion of the belt 32B wound around the drive pulley 32A is located, for example, radially outside the first through hole 41B. The torque of the motor 31 is transmitted to a ball nut of the conversion mechanism 33 via the drive pulley 42A, the belt 32B, and the driven pulley. The drive pulley 32A is a power transmission member.
　なお、駆動プーリ３２Ａおよび従動プーリは、外周面に歯が設けられたタイミングプーリであってもよい。ベルト３２Ｂは、内周面に歯が設けられたタイミングベルトであってもよい。この場合、駆動プーリ３２Ａは、フランジ部３２Ｃを有していてもよい。フランジ部３２Ｃは、ベルト３２Ｂの軸方向への移動を規制するための駆動プーリ３２Ａの部分である。フランジ部３２Ｃは、たとえば、駆動プーリ３２Ａの第２の端部の外周面の全周にわたって設けられている。フランジ部３２Ｃの外周面は、たとえば、駆動プーリ３２Ａに巻かれているベルト３２Ｂの部分の外周面に対して径方向内側に位置する。また、フランジ部３２Ｃの外周面は、たとえば、駆動プーリ３２Ａに巻かれているベルト３２Ｂの部分の内周面に対して径方向外側に位置する。フランジ部３２Ｃは、駆動プーリ３２Ａの第１の端部から第２の端部へ向かう方向のベルト３２Ｂの移動を規制する。 The driving pulley 32A and the driven pulley may be timing pulleys having teeth on their outer circumferential surfaces. The belt 32B may be a timing belt having teeth on its inner circumferential surface. In this case, the driving pulley 32A may have a flange portion 32C. The flange portion 32C is a portion of the driving pulley 32A for restricting the axial movement of the belt 32B. The flange portion 32C is provided, for example, around the entire circumference of the outer circumferential surface of the second end portion of the driving pulley 32A. The outer circumferential surface of the flange portion 32C is, for example, located radially inward relative to the outer circumferential surface of the portion of the belt 32B wound around the driving pulley 32A. The outer circumferential surface of the flange portion 32C is, for example, located radially outward relative to the inner circumferential surface of the portion of the belt 32B wound around the driving pulley 32A. The flange portion 32C restricts the movement of the belt 32B in the direction from the first end portion to the second end portion of the driving pulley 32A.
　＜ベルト３２Ｂの摩耗について＞
　伝動機構３２がベルト伝動機構である場合、つぎのような懸念がある。すなわち、伝動機構３２の長期の使用に伴い、たとえば、ベルト３２Ｂが摩耗する。この摩耗によって発生する摩耗粉が、モータ３１の出力軸４４を支持する第１の軸受４６の内部に侵入することにより、第１の軸受４６の円滑な動作が阻害されることが懸念される。そこで、本実施の形態では、摩耗粉などの異物が第１の軸受４６の内部に侵入することを抑制するために、つぎのような構成を採用している。 <Wear of belt 32B>
When the power transmission mechanism 32 is a belt power transmission mechanism, the following concerns arise. That is, for example, the belt 32B wears with long-term use of the power transmission mechanism 32. There is a concern that wear powder generated by this wear may enter the inside of the first bearing 46 that supports the output shaft 44 of the motor 31, thereby hindering the smooth operation of the first bearing 46. Therefore, in this embodiment, the following configuration is adopted to prevent foreign matter such as wear powder from entering the inside of the first bearing 46.
　＜異物の侵入抑制構造＞
　図３に示すように、モータケース４１は、突部４１Ｃを有している。突部４１Ｃは、モータケース４１の第１の端部に設けられている。突部４１Ｃは、円形の断面形状を有する筒状であって、第１の貫通孔４１Ｂの周囲を囲んでいる。突部４１Ｃは、モータケース４１の第１の端面から軸方向外側に延びている。第１の端面は、モータケース４１の端壁の外面である。突部４１は、先端面を有している。先端面は、モータケース４１の第１の端面と反対側の突部４１Ｃの端面である。先端面は、軸方向に直交する方向に広がる平面である。突部４１Ｃの内径は、第１の貫通孔４１Ｂの内径と同じである。 <Structure to prevent intrusion of foreign objects>
As shown in FIG. 3, the motor case 41 has a protrusion 41C. The protrusion 41C is provided at a first end of the motor case 41. The protrusion 41C is tubular with a circular cross-sectional shape and surrounds the periphery of the first through hole 41B. The protrusion 41C extends axially outward from a first end face of the motor case 41. The first end face is the outer surface of the end wall of the motor case 41. The protrusion 41 has a tip face. The tip face is the end face of the protrusion 41C opposite to the first end face of the motor case 41. The tip face is a flat surface extending in a direction perpendicular to the axial direction. The inner diameter of the protrusion 41C is the same as the inner diameter of the first through hole 41B.
　モータケース４１の第１の端面と、駆動プーリ３２Ａの第２の端面との間の軸方向距離が一定である場合、突部４１Ｃの軸方向長さの分だけ、モータケース４１と駆動プーリ３２Ａとの間の軸方向隙間Ｌ１が狭くなる。このため、ベルト３２Ｂの摩耗粉などの異物の侵入が、モータケース４１の内部に侵入することが抑制される。軸方向隙間Ｌ１は、ベルト３２Ｂの摩耗粉などの異物の侵入経路である。 When the axial distance between the first end face of the motor case 41 and the second end face of the drive pulley 32A is constant, the axial gap L1 between the motor case 41 and the drive pulley 32A is narrowed by the axial length of the protrusion 41C. This prevents foreign matter such as wear powder from the belt 32B from entering the inside of the motor case 41. The axial gap L1 is an entry path for foreign matter such as wear powder from the belt 32B.
　異物の侵入抑制構造の構成パターンとして、３つの構成パターンが考えられる。
　＜第１の構成パターン＞
　第１の構成パターンは、突部４１の内径Ｄ１と、駆動プーリ３２Ａの外径Ｄ２とが、つぎの関係式（１）を満たすときの態様である。外径Ｄ２は、駆動プーリ３２Ａの最外径である。駆動プーリ３２Ｂがフランジ部３２Ｃを有する場合、駆動プーリ３２Ｂの最外径は、フランジ部３２Ｃの外径である。 There are three possible configuration patterns for the foreign matter intrusion prevention structure.
<First Configuration Pattern>
The first configuration pattern is a mode in which the inner diameter D1 of the protrusion 41 and the outer diameter D2 of the drive pulley 32A satisfy the following relational expression (1). The outer diameter D2 is the outermost diameter of the drive pulley 32A. When the drive pulley 32B has a flange portion 32C, the outermost diameter of the drive pulley 32B is the outer diameter of the flange portion 32C.
　Ｄ１＜Ｄ２　…（１）
　ただし、関係式（１）は、突部４１Ｃの先端面が、駆動プーリ３２Ａの第２の端面に対して軸方向に対向する程度に、突部４１Ｃの内径Ｄ１が駆動プーリ３２Ａの外径Ｄ２よりも小さくなる関係を示す。 D1 < D2 ... (1)
However, the relationship (1) indicates that the inner diameter D1 of the protrusion 41C is smaller than the outer diameter D2 of the drive pulley 32A to the extent that the tip surface of the protrusion 41C axially faces the second end surface of the drive pulley 32A.
　図４に示すように、突部４１Ｃは、第１の外側傾斜面４１Ｄを有している。第１の外側傾斜面４１Ｄは、突部４１Ｃの外周面と突部４１Ｃの先端面との間の外側角部の全周にわたって設けられている。第１の外側傾斜面４１Ｄは、突部４１Ｃの先端に向かうにつれて外径が小さくなるように傾斜している。 As shown in FIG. 4, the protrusion 41C has a first outer inclined surface 41D. The first outer inclined surface 41D is provided around the entire circumference of the outer corner between the outer peripheral surface of the protrusion 41C and the tip surface of the protrusion 41C. The first outer inclined surface 41D is inclined so that the outer diameter becomes smaller toward the tip of the protrusion 41C.
　駆動プーリ３２Ａは、第２の外側傾斜面３２Ｄを有している。第２の外側傾斜面３２Ｄは、駆動プーリ３２Ａの第２の端面と、フランジ部３２Ｃの外周面との間の外側角部の全周にわたって設けられている。第２の外側傾斜面３２Ｄは、駆動プーリ３２Ａの第２の端部に向かうにつれて外径が小さくなるように傾斜している。 The drive pulley 32A has a second outer inclined surface 32D. The second outer inclined surface 32D is provided around the entire circumference of the outer corner between the second end face of the drive pulley 32A and the outer circumferential surface of the flange portion 32C. The second outer inclined surface 32D is inclined so that the outer diameter becomes smaller toward the second end face of the drive pulley 32A.
　軸方向隙間Ｌ１は、第１の内側隙間Ｌ１１と、第１の外側隙間Ｌ１２とを含む。第１の内側隙間Ｌ１１は、径方向内側の軸方向隙間Ｌ１の領域であって、突部４１Ｃの先端面と駆動プーリ３２Ａの第２の端面との間の軸方向隙間Ｌ１の領域である。第１の外側隙間Ｌ１２は、径方向外側の軸方向隙間Ｌ１の領域であって、突部４１Ｃの先端面と駆動プーリ３２Ａの第２の外側傾斜面３２Ｄとの間の軸方向隙間Ｌ１の領域である。第１の外側隙間Ｌ１２は、径方向外側に向かうにつれて、軸方向長さが長くなる。第１の外側隙間Ｌ１２の軸方向長さは、突部４１Ｃの先端面と、第２の外側傾斜面３２Ｄとフランジ部３２Ｃの外周面とが交わる外側角部との間において最大となる。第１の外側隙間Ｌ１２の軸方向長さは、第１の内側隙間Ｌ１１の軸方向長さよりも長い。 The axial gap L1 includes a first inner gap L11 and a first outer gap L12. The first inner gap L11 is the region of the axial gap L1 on the radially inner side, which is the region of the axial gap L1 between the tip surface of the protrusion 41C and the second end surface of the drive pulley 32A. The first outer gap L12 is the region of the axial gap L1 on the radially outer side, which is the region of the axial gap L1 between the tip surface of the protrusion 41C and the second outer inclined surface 32D of the drive pulley 32A. The axial length of the first outer gap L12 increases as it moves radially outward. The axial length of the first outer gap L12 is maximum between the tip surface of the protrusion 41C and the outer corner where the second outer inclined surface 32D and the outer peripheral surface of the flange portion 32C intersect. The axial length of the first outer gap L12 is longer than the axial length of the first inner gap L11.
　ベルト３２Ｂの摩耗粉などの異物は、第１の外側隙間Ｌ１２、および第１の内側隙間Ｌ１１の順に侵入し得る。第１の外側隙間Ｌ１２は、異物の入り口である。
　突起４１Ｃの先端面は、駆動プーリ３２Ａの第２の端面に対して軸方向に対向している。このため、出力軸４４に駆動プーリ３２Ａを組み合わせる際、軸方向の組立公差のばらつきに起因して、突部４１Ｃの先端面と、駆動プーリ３２Ａの第２の端面とが、互いに軸方向に接触するおそれがある。したがって、第１の内側隙間Ｌ１１には、出力軸４４に対する駆動プーリ３２Ａの軸方向の組立公差を吸収するために、定められた軸方向長さだけ確保することが要求されることがある。 Foreign matter such as wear powder of the belt 32B can enter the first outer gap L12 and then the first inner gap L11. The first outer gap L12 is an entrance for foreign matter.
The tip surface of the projection 41C faces the second end surface of the drive pulley 32A in the axial direction. Therefore, when the drive pulley 32A is assembled to the output shaft 44, the tip surface of the projection 41C and the second end surface of the drive pulley 32A may come into contact with each other in the axial direction due to variations in axial assembly tolerances. Therefore, the first inner gap L11 may be required to have a predetermined axial length in order to absorb the axial assembly tolerances of the drive pulley 32A relative to the output shaft 44.
　＜第２の構成パターン＞
　第２の構成パターンは、突部４１Ｃの内径Ｄ１と、駆動プーリ３２Ａの外径Ｄ２とが、つぎの関係式（２）を満たすときの態様である。外径Ｄ２は、駆動プーリ３２Ａの最外径である。駆動プーリ３２Ｂがフランジ部３２Ｃを有する場合、駆動プーリ３２Ｂの最外径は、フランジ部３２Ｃの外径である。 <Second Configuration Pattern>
The second configuration pattern is a mode in which the inner diameter D1 of the protrusion 41C and the outer diameter D2 of the drive pulley 32A satisfy the following relational expression (2). The outer diameter D2 is the outermost diameter of the drive pulley 32A. When the drive pulley 32B has a flange portion 32C, the outermost diameter of the drive pulley 32B is the outer diameter of the flange portion 32C.
　Ｄ１＝Ｄ２　…（２）
　ただし、関係式（２）は、突部４１Ｃの内径Ｄ１と、駆動プーリ３２Ａの外径Ｄ２とが同じであること、および突部４１Ｃの内径Ｄ１が駆動プーリ３２Ａの外径Ｄ２よりも若干小さいことを含む。若干小さいとは、たとえば、突部４１Ｃの先端面が、駆動プーリ３２Ａの第２の外側傾斜面３２Ｄに対して軸方向に対向する程度であることをいう。 D1 = D2 ... (2)
However, the relational expression (2) includes the conditions that the inner diameter D1 of the protrusion 41C and the outer diameter D2 of the drive pulley 32A are the same, and that the inner diameter D1 of the protrusion 41C is slightly smaller than the outer diameter D2 of the drive pulley 32A. "Slightly smaller" means, for example, that the tip surface of the protrusion 41C faces the second outer inclined surface 32D of the drive pulley 32A in the axial direction.
　図５に示すように、たとえば、突部４１Ｃの内径Ｄ１が、理想的には、駆動プーリ３２Ａの外径Ｄ２と同じに設定されている。駆動プーリ３２Ａは、先の第１の構成パターンと同様に、第２の外側傾斜面３２Ｄを有している。 As shown in FIG. 5, for example, the inner diameter D1 of the protrusion 41C is ideally set to be the same as the outer diameter D2 of the drive pulley 32A. The drive pulley 32A has a second outer inclined surface 32D, similar to the first configuration pattern described above.
　軸方向隙間Ｌ１は、第２の内側隙間Ｌ２１と、第２の外側隙間Ｌ２２とを含む。第１の内側隙間Ｌ２１は、径方向内側の軸方向隙間Ｌ１の領域であって、突部４１Ｃの先端面と、駆動プーリ３２Ａの第２の端面との間の軸方向隙間Ｌ１の領域である。第２の外側隙間Ｌ２２は、径方向外側の軸方向隙間Ｌ１の領域であって、突部４１Ｃの先端面と、第２の外側傾斜面３２Ｄとフランジ部３２Ｃの外周面とが交わる外側角部との間の軸方向隙間Ｌ１の領域である。第２の外側隙間Ｌ２２の軸方向長さは、第２の内側隙間Ｌ２１の軸方向長さよりも長い。 The axial gap L1 includes a second inner gap L21 and a second outer gap L22. The first inner gap L21 is the region of the axial gap L1 on the radially inner side, which is the region of the axial gap L1 between the tip surface of the protrusion 41C and the second end surface of the drive pulley 32A. The second outer gap L22 is the region of the axial gap L1 on the radially outer side, which is the region of the axial gap L1 between the tip surface of the protrusion 41C and the outer corner where the second outer inclined surface 32D and the outer peripheral surface of the flange portion 32C intersect. The axial length of the second outer gap L22 is longer than the axial length of the second inner gap L21.
　ベルト３２Ｂの摩耗粉などの異物は、第２の外側隙間Ｌ２２、および第２の内側隙間Ｌ２１の順に侵入し得る。第２の外側隙間Ｌ２２は、異物の入り口である。
　突部４１Ｃの内周面と突部４１Ｃの先端面とが交わる内側角部は、第２の外側傾斜面３２Ｄとフランジ部３２Ｃの外周面とが交わる駆動プーリ３２Ａの外側角部に対して軸方向に対向する。このため、出力軸４４と駆動プーリ３２Ａとを組み立てる際、軸方向の組立公差のばらつきに起因して、突部４１Ｃの内側角部が、駆動プーリ３２Ａの外側角部に対して軸方向に接触するおそれがある。このため、第２の外側隙間Ｌ２２には、出力軸４４に対する駆動プーリ３２Ａの軸方向の組立公差を吸収するために、定められた軸方向長さだけ確保することが要求されることがある。 Foreign matter such as wear powder of the belt 32B can enter the second outer gap L22 and then the second inner gap L21. The second outer gap L22 is an entrance for foreign matter.
An inner corner where the inner peripheral surface of the protrusion 41C and the tip surface of the protrusion 41C intersect faces an outer corner of the drive pulley 32A where the second outer inclined surface 32D and the outer peripheral surface of the flange portion 32C intersect in the axial direction. Therefore, when assembling the output shaft 44 and the drive pulley 32A, there is a risk that the inner corner of the protrusion 41C will come into contact with the outer corner of the drive pulley 32A in the axial direction due to variations in axial assembly tolerances. Therefore, the second outer gap L22 may be required to have a predetermined axial length in order to absorb the axial assembly tolerances of the drive pulley 32A relative to the output shaft 44.
　第２の外側隙間Ｌ２２の軸方向長さは、たとえば、第１の構成パターンにおける第１の内側隙間Ｌ１１の軸方向長さと同じ長さに設定される。このため、第２の外側隙間Ｌ２２の軸方向長さは、第１の構成パターンにおける第１の外側隙間Ｌ１２の軸方向長さよりも短くなる。すなわち、図４に示される第１の構成パターンと比較して、突起４１Ｃの先端面は、第１の外側隙間Ｌ１２と第２の外側隙間Ｌ２２の軸方向長さとの差の分だけ、駆動プーリ３２Ａの第２の端面に軸方向に近接している。このため、第２の内側隙間Ｌ２１の軸方向長さは、先の第１の構成パターンにおける第１の内側隙間Ｌ１１の軸方向長さよりも短くなる。したがって、第２の外側隙間Ｌ２２と第２の内側隙間Ｌ２１とからなる第２の構成パターンの異物の侵入経路は、第１の外側隙間Ｌ１２と第１の内側隙間Ｌ１１とからなる第１の構成パターンの異物の侵入経路よりも軸方向に狭くなる。 The axial length of the second outer gap L22 is set to, for example, the same length as the axial length of the first inner gap L11 in the first configuration pattern. Therefore, the axial length of the second outer gap L22 is shorter than the axial length of the first outer gap L12 in the first configuration pattern. That is, compared to the first configuration pattern shown in FIG. 4, the tip surface of the protrusion 41C is axially closer to the second end surface of the drive pulley 32A by the difference between the axial lengths of the first outer gap L12 and the second outer gap L22. Therefore, the axial length of the second inner gap L21 is shorter than the axial length of the first inner gap L11 in the first configuration pattern. Therefore, the intrusion path of foreign matter in the second configuration pattern consisting of the second outer gap L22 and the second inner gap L21 is axially narrower than the intrusion path of foreign matter in the first configuration pattern consisting of the first outer gap L12 and the first inner gap L11.
　なお、第２の構成パターンは、突部４１Ｃの内径Ｄ１が駆動プーリ３２Ａの外径Ｄ２よりも若干小さい場合を含む。この場合、突部４１Ｃの内側角部が、駆動プーリ３２Ａの第２の外側傾斜面３２Ｄに対して軸方向に対向する。突部４１Ｃの内側角部と、駆動プーリ３２Ａの第２の外側傾斜面３２Ｄとの間の軸方向長さは、たとえば、図５に示される第２の外側隙間Ｌ２２の軸方向長さと同様の長さに設定される。 The second configuration pattern includes a case where the inner diameter D1 of the protrusion 41C is slightly smaller than the outer diameter D2 of the drive pulley 32A. In this case, the inner corner of the protrusion 41C faces the second outer inclined surface 32D of the drive pulley 32A in the axial direction. The axial length between the inner corner of the protrusion 41C and the second outer inclined surface 32D of the drive pulley 32A is set to, for example, the same length as the axial length of the second outer gap L22 shown in FIG. 5.
　＜第３の構成パターン＞
　第３の構成パターンは、突部４１Ｃの内径Ｄ１と、駆動プーリ３２Ａの外径Ｄ２とが、つぎの関係式（３）を満たすときの態様である。外径Ｄ２は、駆動プーリ３２Ａの最外径である。駆動プーリ３２Ｂがフランジ部３２Ｃを有する場合、駆動プーリ３２Ｂの最外径は、フランジ部３２Ｃの外径である。 <Third Configuration Pattern>
The third configuration pattern is a mode in which the inner diameter D1 of the protrusion 41C and the outer diameter D2 of the drive pulley 32A satisfy the following relational expression (3). The outer diameter D2 is the outermost diameter of the drive pulley 32A. When the drive pulley 32B has a flange portion 32C, the outermost diameter of the drive pulley 32B is the outer diameter of the flange portion 32C.
　Ｄ１＞Ｄ２　…（３）
　突部４１Ｃの内径Ｄ１が駆動プーリ３２Ａの外径Ｄ２よりも大きいため、駆動プーリ３２Ａの第２の端部を突部４１Ｃの内部に挿入可能である。このため、出力軸４４と駆動プーリ３２Ａとを組み立てる際、軸方向の組立公差のばらつきに起因して、突部４１Ｃの先端面と、駆動プーリ３２Ａとが、互いに軸方向に接触することが抑制される。 D1>D2 ... (3)
Since the inner diameter D1 of the protrusion 41C is larger than the outer diameter D2 of the drive pulley 32A, the second end of the drive pulley 32A can be inserted into the protrusion 41C. Therefore, when assembling the output shaft 44 and the drive pulley 32A, the tip surface of the protrusion 41C and the drive pulley 32A are prevented from coming into contact with each other in the axial direction due to variations in assembly tolerance in the axial direction.
　出力軸４４と駆動プーリ３２Ａとは、たとえば、突部４１Ｃの内部に駆動プーリ３２Ａの第２の端部が挿入された状態に維持されるように組み合わせられる。この場合、突部４１Ｃの内周面と駆動プーリ３２Ａの外周面とは、互いに径方向に対向する。すなわち、突部４１Ｃの内周面と駆動プーリ３２Ａの外周面との間には、径方向隙間が形成される。径方向隙間は、ベルト３２Ｂの摩耗粉などの異物の侵入経路となる。 The output shaft 44 and the drive pulley 32A are assembled, for example, so that the second end of the drive pulley 32A is maintained inserted inside the protrusion 41C. In this case, the inner peripheral surface of the protrusion 41C and the outer peripheral surface of the drive pulley 32A face each other radially. That is, a radial gap is formed between the inner peripheral surface of the protrusion 41C and the outer peripheral surface of the drive pulley 32A. The radial gap provides an entry path for foreign matter such as wear powder from the belt 32B.
　突部４１Ｃの内周面と駆動プーリ３２Ａの外周面との径方向隙間の径方向長さは、たとえば、図５に示される第２の構成パターンにおける第２の外側隙間Ｌ２２の軸方向長さと同じ長さに設定してもよい。また、突部４１Ｃの内周面と駆動プーリ３２Ａの外周面との径方向隙間の径方向長さは、第２の構成パターンにおける第２の外側隙間Ｌ２２の軸方向長さよりも短い長さに設定してもよい。この場合、第３の構成パターンの異物の侵入経路は、第２の構成パターンの異物の侵入経路よりもさらに狭くなる。 The radial length of the radial gap between the inner circumferential surface of the protrusion 41C and the outer circumferential surface of the drive pulley 32A may be set to, for example, the same length as the axial length of the second outer gap L22 in the second configuration pattern shown in FIG. 5. The radial length of the radial gap between the inner circumferential surface of the protrusion 41C and the outer circumferential surface of the drive pulley 32A may also be set to a length shorter than the axial length of the second outer gap L22 in the second configuration pattern. In this case, the entry path of foreign matter in the third configuration pattern is even narrower than the entry path of foreign matter in the second configuration pattern.
　なお、製品仕様によっては、駆動プーリ３２Ａの第２の端部を突部４１Ｃの内部に挿入しないようにしてもよい。この場合、突部４１Ｃの内径と、駆動プーリ３２Ａの外径との差は、小さいほどよい。また、突部４１Ｃの先端面と、駆動プーリ３２Ａの第２の端面との軸方向の距離は、短いほどよい。 Depending on the product specifications, the second end of the drive pulley 32A may not be inserted inside the protrusion 41C. In this case, the smaller the difference between the inner diameter of the protrusion 41C and the outer diameter of the drive pulley 32A, the better. Also, the shorter the axial distance between the tip surface of the protrusion 41C and the second end surface of the drive pulley 32A, the better.
　＜第１の軸受４６の構成＞
　つぎに、第１の軸受４６について詳細に説明する。
　図６に示すように、第１の軸受４６は、シール形ベアリングであってもよい。第１の軸受４６は、内輪４６Ａと、外輪４６Ｂと、複数のボール４６Ｃとを有している。内輪４６Ａの内周面は、出力軸４４の外周面に嵌められる。外輪４６Ｂの外周面は、モータケース４１の第１の軸受支持部４１Ａの内周面に嵌められている。ボール４６Ｃは、内輪４６Ａと、外輪４６Ｂとの間に保持されている。ボール４６Ｃは、出力軸４４の回転に伴い、内輪４６Ａと外輪４６Ｂとの間で転動する。 <Configuration of first bearing 46>
Next, the first bearing 46 will be described in detail.
As shown in Fig. 6, the first bearing 46 may be a sealed bearing. The first bearing 46 has an inner ring 46A, an outer ring 46B, and a plurality of balls 46C. The inner peripheral surface of the inner ring 46A is fitted to the outer peripheral surface of the output shaft 44. The outer peripheral surface of the outer ring 46B is fitted to the inner peripheral surface of the first bearing support portion 41A of the motor case 41. The balls 46C are held between the inner ring 46A and the outer ring 46B. The balls 46C roll between the inner ring 46A and the outer ring 46B as the output shaft 44 rotates.
　第１の軸受４６は、シール部材４６Ｄを有している。シール部材４６Ｄは、ゴム製の環状板である。シール部材４６Ｄは、第１の軸受４６の第１の端部に装着されている。第１の端部は、軸方向において突部４１Ｃに近い側の第１の軸受４６の端部である。内輪４６Ａと外輪４６Ｂとの間の隙間は、軸方向に開口している。シール部材４６Ｄは、内輪４６Ａと外輪４６Ｂとの間の隙間における軸方向開口部を密封している。シール部材４６Ｄは、内輪４６Ａの第１の端部と、外輪４６Ｂの第１の端部とに接触した状態に維持される。内輪４６Ａは、シール部材４６Ｄに対して摺動回転する。 The first bearing 46 has a seal member 46D. The seal member 46D is an annular plate made of rubber. The seal member 46D is attached to a first end of the first bearing 46. The first end is the end of the first bearing 46 that is closer to the protrusion 41C in the axial direction. The gap between the inner ring 46A and the outer ring 46B is open in the axial direction. The seal member 46D seals the axial opening in the gap between the inner ring 46A and the outer ring 46B. The seal member 46D is maintained in contact with the first end of the inner ring 46A and the first end of the outer ring 46B. The inner ring 46A slides and rotates relative to the seal member 46D.
　なお、シール部材４６Ｄは、第１の軸受４６の第２の端部には装着されていない。第２の端部は、第１の端部と反対側の端部であって、軸方向において突部４１Ｃから遠い側の第１の軸受４６の端部である。ただし、製品仕様によっては、シール部材４６Ｄを、第１の軸受４６の第２の端部に装着してもよい。 The seal member 46D is not attached to the second end of the first bearing 46. The second end is the end opposite the first end, and is the end of the first bearing 46 farther from the protrusion 41C in the axial direction. However, depending on the product specifications, the seal member 46D may be attached to the second end of the first bearing 46.
　第１の軸受４６は、２つのＯリング４６Ｅを有している。Ｏリング４６Ｅは、ゴム製である。Ｏリング４６Ｅは、無端状であって、円形状である。外輪４６Ｂの外周面には、２つの環状溝４６Ｆが設けられている。２つの環状溝４６Ｆは、軸方向に間隔をあけて配置されている。Ｏリング４６Ｅは、２つの環状溝４６Ｆに各々装着されている。第１の軸受４６がモータケース４１の第１の軸受支持部４１Ａに装着された状態において、Ｏリング４６Ｅが径方向内側に圧縮されることにより、外輪４６Ｂの外周面と第１の軸受支持部４１Ａの内周面との間が密封される。 The first bearing 46 has two O-rings 46E. The O-rings 46E are made of rubber. The O-rings 46E are endless and circular. Two annular grooves 46F are provided on the outer peripheral surface of the outer ring 46B. The two annular grooves 46F are arranged with a gap in the axial direction. An O-ring 46E is attached to each of the two annular grooves 46F. When the first bearing 46 is attached to the first bearing support portion 41A of the motor case 41, the O-rings 46E are compressed radially inward to form a seal between the outer peripheral surface of the outer ring 46B and the inner peripheral surface of the first bearing support portion 41A.
　＜本実施の形態の効果＞
　本実施の形態は、以下の作用および効果を奏する。
　（１）モータケース４１は、突部４１Ｃを有している。突部４１Ｃは、モータケース４１の端壁の外面において、第１の貫通孔４１Ｂを囲むように設けられている。突部４１Ｃは、モータケース４１の端壁の外面から軸方向外側に延びている。突部４１Ｃの先端面と、駆動プーリ３２Ａの第２の端面との間の軸方向隙間Ｌ１は、モータケース４１の端壁の外面と、駆動プーリ３２Ａの第２の端面との間の軸方向隙間よりも狭い。このため、モータケース４１が突部４１Ｃを有さない場合に比べて、異物の侵入経路を軸方向に狭めることができる。したがって、モータ３１の第１の軸受４６の内部に、異物が侵入しにくくなる。第１の軸受４６に対する異物侵入のリスクが低減されることにより、第１の軸受４６、ひいては転舵機構１１の動作に対する信頼性を向上させることができる。異物は、ベルト３２Ｂの摩耗紛、あるいはグリースを含む。 <Effects of this embodiment>
The present embodiment provides the following actions and effects.
(1) The motor case 41 has a protrusion 41C. The protrusion 41C is provided on the outer surface of the end wall of the motor case 41 so as to surround the first through hole 41B. The protrusion 41C extends axially outward from the outer surface of the end wall of the motor case 41. The axial gap L1 between the tip surface of the protrusion 41C and the second end surface of the drive pulley 32A is narrower than the axial gap between the outer surface of the end wall of the motor case 41 and the second end surface of the drive pulley 32A. Therefore, compared to a case in which the motor case 41 does not have the protrusion 41C, the intrusion path of foreign matter can be narrowed in the axial direction. Therefore, foreign matter is less likely to intrude into the inside of the first bearing 46 of the motor 31. By reducing the risk of foreign matter intrusion into the first bearing 46, the reliability of the operation of the first bearing 46 and therefore the steering mechanism 11 can be improved. The foreign matter includes wear powder of the belt 32B or grease.
　（２）第１の構成パターンが採用される場合、突部４１Ｃの内径Ｄ１が駆動プーリ３２Ａの外径Ｄ２よりも小さい。また、突起４１Ｃの先端面が、駆動プーリ３２Ａの第２の端面に対して軸方向に対向する。このため、出力軸４４に駆動プーリ３２Ａを組み合わせる際、軸方向の組立公差のばらつきに起因して、突部４１Ｃの先端面と駆動プーリ３２Ａの第２の端面とが、互いに軸方向に接触するおそれがある。この点、本実施の形態では、突部４１Ｃの先端面と、駆動プーリ３２Ａの第２の端面との間には、第１の内側隙間Ｌ１１が設けられている。第１の内側隙間Ｌ１１は、出力軸４４に対する駆動プーリ３２Ａの軸方向の組立公差を吸収する観点から定められた軸方向長さを有する。これにより、出力軸４４に駆動プーリ３２Ａを組み合わせる際、突部４１Ｃの先端面と駆動プーリ３２Ａの第２の端面との軸方向の接触を抑制することができる。 (2) When the first configuration pattern is adopted, the inner diameter D1 of the protrusion 41C is smaller than the outer diameter D2 of the drive pulley 32A. Also, the tip surface of the protrusion 41C faces the second end surface of the drive pulley 32A in the axial direction. Therefore, when the drive pulley 32A is assembled to the output shaft 44, the tip surface of the protrusion 41C and the second end surface of the drive pulley 32A may come into contact with each other in the axial direction due to variations in the axial assembly tolerance. In this regard, in the present embodiment, a first inner gap L11 is provided between the tip surface of the protrusion 41C and the second end surface of the drive pulley 32A. The first inner gap L11 has an axial length determined from the viewpoint of absorbing the axial assembly tolerance of the drive pulley 32A relative to the output shaft 44. As a result, when the drive pulley 32A is assembled to the output shaft 44, axial contact between the tip surface of the protrusion 41C and the second end surface of the drive pulley 32A can be suppressed.
　（３）第２の構成パターンが採用される場合、突部４１Ｃの内径Ｄ１が駆動プーリ３２Ａの外径Ｄ２と同じである。また、突部４１Ｃの内周面と突部４１Ｃの先端面とが交わる内側角部が、第２の外側傾斜面３２Ｄとフランジ部３２Ｃの外周面とが交わる外側角部に対して軸方向に対向する。このため、出力軸４４に駆動プーリ３２Ａを組み合わせる際、軸方向の組立公差のばらつきに起因して、突部４１Ｃの内側角部と、駆動プーリ３２Ａの外側角部とが、互いに軸方向に接触するおそれがある。この点、本実施の形態では、突部４１Ｃの内側角部と、駆動プーリ３２Ａの外側角部との間には、第２の外側隙間Ｌ２２が設けられている。第２の外側隙間Ｌ２２は、出力軸４４に対する駆動プーリ３２Ａの軸方向の組立公差を吸収する観点から定められた軸方向長さを有する。これにより、出力軸４４に駆動プーリ３２Ａを組み合わせる際、突部４１Ｃの内側角部と駆動プーリ３２Ａの外側角部との軸方向の接触を抑制することができる。 (3) When the second configuration pattern is adopted, the inner diameter D1 of the protrusion 41C is the same as the outer diameter D2 of the drive pulley 32A. In addition, the inner corner where the inner peripheral surface of the protrusion 41C and the tip surface of the protrusion 41C intersect faces the outer corner where the second outer inclined surface 32D and the outer peripheral surface of the flange portion 32C intersect in the axial direction. Therefore, when assembling the drive pulley 32A to the output shaft 44, there is a risk that the inner corner of the protrusion 41C and the outer corner of the drive pulley 32A will come into contact with each other in the axial direction due to variations in the axial assembly tolerance. In this regard, in this embodiment, a second outer gap L22 is provided between the inner corner of the protrusion 41C and the outer corner of the drive pulley 32A. The second outer gap L22 has an axial length determined from the viewpoint of absorbing the axial assembly tolerance of the drive pulley 32A relative to the output shaft 44. This makes it possible to prevent axial contact between the inner corner of the protrusion 41C and the outer corner of the drive pulley 32A when combining the output shaft 44 with the drive pulley 32A.
　（４）第２の構成パターンが採用される場合、第２の外側隙間Ｌ２２の軸方向長さは、たとえば、図４に示される第１の構成パターンにおける先の第１の内側隙間Ｌ１１の軸方向長さと同じ長さに設定される。この場合、第２の外側隙間Ｌ２２の軸方向長さは、第１の構成パターンにおける第１の外側隙間Ｌ１２の軸方向長さよりも短くなる。このため、第１の構成パターンに対して、突部４１Ｃの先端面を、第１の外側隙間Ｌ１２と第２の外側隙間Ｌ２２の軸方向長さとの差の分だけ、駆動プーリ３２Ａの第２の端面に軸方向に近接させることができる。すなわち、第２の内側隙間Ｌ２１の軸方向長さは、第１の構成パターンにおける第１の内側隙間Ｌ１１の軸方向長さよりも短くなる。したがって、第２の外側隙間Ｌ２２と第２の内側隙間Ｌ２１とからなる第２の構成パターンの異物の侵入経路は、第１の外側隙間Ｌ１２と第１の内側隙間Ｌ１１とからなる第１の構成パターンの異物の侵入経路よりも軸方向に狭い。このため、ベルト３２Ｂの摩耗粉などの異物が第１の軸受４６の内部に侵入することを、より抑制することができる。 (4) When the second configuration pattern is adopted, the axial length of the second outer gap L22 is set to, for example, the same length as the axial length of the first inner gap L11 in the first configuration pattern shown in FIG. 4. In this case, the axial length of the second outer gap L22 is shorter than the axial length of the first outer gap L12 in the first configuration pattern. Therefore, with respect to the first configuration pattern, the tip surface of the protrusion 41C can be brought axially closer to the second end surface of the drive pulley 32A by the difference between the axial lengths of the first outer gap L12 and the second outer gap L22. That is, the axial length of the second inner gap L21 is shorter than the axial length of the first inner gap L11 in the first configuration pattern. Therefore, the intrusion path of foreign matter in the second configuration pattern consisting of the second outer gap L22 and the second inner gap L21 is narrower in the axial direction than the intrusion path of foreign matter in the first configuration pattern consisting of the first outer gap L12 and the first inner gap L11. This makes it possible to further prevent foreign matter, such as wear powder from the belt 32B, from entering the inside of the first bearing 46.
　（５）第２の構成パターンは、突部４１Ｃの内径Ｄ１が駆動プーリ３２Ａの外径Ｄ２よりも若干小さい場合を含む。この場合、突部４１Ｃの内側角部が、駆動プーリ３２Ａの第２の外側傾斜面３２Ｄに対して軸方向に対向する。突部４１Ｃの内側角部と、駆動プーリ３２Ａの第２の外側傾斜面３２Ｄとの間の軸方向長さは、たとえば、図５に示される第２の外側隙間Ｌ２２の軸方向長さと同様の長さに設定される。このため、先の（４），（５）欄に記載の効果と同様の効果を奏する。 (5) The second configuration pattern includes a case where the inner diameter D1 of the protrusion 41C is slightly smaller than the outer diameter D2 of the drive pulley 32A. In this case, the inner corner of the protrusion 41C faces the second outer inclined surface 32D of the drive pulley 32A in the axial direction. The axial length between the inner corner of the protrusion 41C and the second outer inclined surface 32D of the drive pulley 32A is set to, for example, the same length as the axial length of the second outer gap L22 shown in FIG. 5. This provides the same effects as those described in sections (4) and (5) above.
　（６）第３の構成パターンが採用される場合、突部４１Ｃの内径Ｄ１が駆動プーリ３２Ａの外径Ｄ２よりも大きい。また、駆動プーリ３２Ａの第２の端部を突部４１Ｃの内部に挿入可能である。このため、出力軸４４に駆動プーリ３２Ａを組み合わせる際、軸方向の組立公差のばらつきに起因して、突部４１Ｃの先端面と、駆動プーリ３２Ａとが、互いに軸方向に接触することを抑制することができる。 (6) When the third configuration pattern is adopted, the inner diameter D1 of the protrusion 41C is larger than the outer diameter D2 of the drive pulley 32A. In addition, the second end of the drive pulley 32A can be inserted inside the protrusion 41C. Therefore, when combining the drive pulley 32A with the output shaft 44, it is possible to prevent the tip surface of the protrusion 41C and the drive pulley 32A from coming into contact with each other in the axial direction due to variations in assembly tolerances in the axial direction.
　（７）第３の構成パターンが採用される場合、駆動プーリ３２Ａの第２の端部が突部４１Ｃの内部に挿入された状態で、出力軸４４と駆動プーリ３２Ａとを組み合わせることが可能である。この場合、突部４１Ｃの内周面と駆動プーリ３２Ａの外周面との間の径方向隙間が、ベルト３２Ｂの摩耗粉などの異物の侵入経路となる。径方向隙間の径方向長さは、たとえば、図５に示される第２の構成パターンにおける第２の外側隙間Ｌ２２の軸方向長さよりも短い長さに設定することが可能である。このため、第３の構成パターンの異物の侵入経路を、第２の構成パターンの異物の侵入経路よりも、さらに狭くすることが可能である。したがって、ベルト３２Ｂの摩耗粉などの異物が第１の軸受４６の内部に侵入することを、さらに抑制することができる。 (7) When the third configuration pattern is adopted, the output shaft 44 and the drive pulley 32A can be assembled with the second end of the drive pulley 32A inserted inside the protrusion 41C. In this case, the radial gap between the inner peripheral surface of the protrusion 41C and the outer peripheral surface of the drive pulley 32A becomes a path for foreign matter such as wear powder of the belt 32B to enter. The radial length of the radial gap can be set to a length shorter than the axial length of the second outer gap L22 in the second configuration pattern shown in FIG. 5, for example. Therefore, the path for foreign matter to enter in the third configuration pattern can be made even narrower than the path for foreign matter to enter in the second configuration pattern. Therefore, it is possible to further suppress the entry of foreign matter such as wear powder of the belt 32B into the inside of the first bearing 46.
　（８）第１の軸受４６は、シール部材４６Ｄを有している。シール部材４６Ｄは、内輪４６Ａと外輪４６Ｂとの間の隙間における軸方向開口部であって、突部４１Ｃに近い側の軸方向開口部のみを密封する。ベルト３２Ｂの摩耗粉などの異物は、突部４１Ｃの内部を通って、第１の軸受４６に至る。このため、たとえ異物が第１の軸受４６に至ったとしても、異物が第１の軸受４６の内部に侵入することを抑制することができる。 (8) The first bearing 46 has a seal member 46D. The seal member 46D seals only the axial opening in the gap between the inner ring 46A and the outer ring 46B, which is the axial opening closer to the protrusion 41C. Foreign matter such as wear powder from the belt 32B passes through the inside of the protrusion 41C and reaches the first bearing 46. Therefore, even if a foreign matter reaches the first bearing 46, the foreign matter can be prevented from entering the inside of the first bearing 46.
　（９）シール部材４６Ｄは、たとえば、内輪４６Ａおよび外輪４６Ｂの軸方向端部に接触した状態に設けられる。このため、軸方向において、内輪４６Ａと外輪４６Ｂとの両端部に各々シール部材４６Ｄを設ける場合に比べて、内輪４６とシール部材４６Ｄとの接触による摩擦トルクを小さくすることができる。 (9) The seal member 46D is provided, for example, in contact with the axial ends of the inner ring 46A and the outer ring 46B. This makes it possible to reduce the friction torque caused by contact between the inner ring 46 and the seal member 46D, compared to a case in which a seal member 46D is provided at each end of the inner ring 46A and the outer ring 46B in the axial direction.
　（１０）第１の軸受４６は、Ｏリング４６Ｅを有している。Ｏリング４６Ｅは、外輪４６Ｂの外周面に装着されている。第１の軸受４６がモータケース４１の第１の軸受支持部４１Ａに装着された状態において、Ｏリング４６Ｅが径方向内側に圧縮される。これにより、外輪４６Ｂの外周面と第１の軸受支持部４１Ａの内周面との間が密封される。このため、たとえ異物が第１の軸受４６に至ったとしても、異物が、外輪４６Ｂの外周面と第１の軸受支持部４１Ａの内周面との間の隙間を介して、モータケース４１の内部に侵入することを抑制することができる。 (10) The first bearing 46 has an O-ring 46E. The O-ring 46E is attached to the outer peripheral surface of the outer ring 46B. When the first bearing 46 is attached to the first bearing support portion 41A of the motor case 41, the O-ring 46E is compressed radially inward. This seals the gap between the outer peripheral surface of the outer ring 46B and the inner peripheral surface of the first bearing support portion 41A. Therefore, even if a foreign object reaches the first bearing 46, the foreign object can be prevented from entering the inside of the motor case 41 through the gap between the outer peripheral surface of the outer ring 46B and the inner peripheral surface of the first bearing support portion 41A.
　（１１）出力軸４４の大径部４４Ａは、規制面４４Ｂを有している。規制面４４Ｂは、第２の軸受４７の内輪に軸方向に対向している。規制面４４Ａと第２の軸受４７の内輪との間の第２の隙間δ２は、磁束発生体４８と回転角センサ４８との間の第１の隙間δ１よりも狭くなるように設定される。このため、外力によって、出力軸４４が回転角センサ５２Ｃへ向けて軸方向に移動するとき、磁束発生体４８が回転角センサ５２Ｃに接触する前に、規制面４４Ｂが第２の軸受４の内輪に接触する。したがって、外力によって、出力軸４４が軸方向に移動する場合であれ、磁束発生体４８が回転角センサ５２Ｃに軸方向に接触することを抑制することができる。 (11) The large diameter portion 44A of the output shaft 44 has a restricting surface 44B. The restricting surface 44B faces the inner ring of the second bearing 47 in the axial direction. The second gap δ2 between the restricting surface 44A and the inner ring of the second bearing 47 is set to be narrower than the first gap δ1 between the magnetic flux generator 48 and the rotation angle sensor 48. Therefore, when the output shaft 44 moves axially toward the rotation angle sensor 52C due to an external force, the restricting surface 44B comes into contact with the inner ring of the second bearing 4 before the magnetic flux generator 48 comes into contact with the rotation angle sensor 52C. Therefore, even if the output shaft 44 moves axially due to an external force, the magnetic flux generator 48 can be prevented from coming into contact with the rotation angle sensor 52C in the axial direction.
　（１２）出力軸４４に対する第２の軸受４７の圧入位置を、たとえば、第２の軸受４７の内輪が規制面４４Ａに対して軸方向に接触する位置に設定することが考えられる。この場合、たとえば、モータ３１の組立作業中に、出力軸４４の第１の端部が何らかの物体に衝突したとき、第２の軸受４７にオーバーシュート荷重が加わるおそれがある。オーバーシュート荷重は、過荷重であって、規制面４４Ｂに接触する第２の軸受４７を、さらに出力軸４４に圧入する方向に作用する力である。オーバーシュート荷重によって、第２の軸受４７の内輪が、規制面３３Ｂに対して、さらに押し付けられる。これにより、第２の軸受４７に傷が発生するおそれがある。この点、本実施の形態では、規制面４４Ａと第２の軸受４７の内輪との間に第２の隙間δ２が設けられている。このため、出力軸４４の第１の端部が何らかの物体にぶつかった場合であれ、規制面４４Ｂが第２２の軸受４７の内輪に軸方向に接触することが抑制される。したがって、第２の軸受４７にオーバーシュート荷重が加わることが抑制される。また、第２の軸受４７の傷つきを抑えることができる。 (12) It is possible to set the press-fit position of the second bearing 47 relative to the output shaft 44, for example, to a position where the inner ring of the second bearing 47 contacts the regulating surface 44A in the axial direction. In this case, for example, when the first end of the output shaft 44 collides with some object during the assembly work of the motor 31, an overshoot load may be applied to the second bearing 47. The overshoot load is an overload that acts in a direction that presses the second bearing 47, which is in contact with the regulating surface 44B, further into the output shaft 44. The overshoot load presses the inner ring of the second bearing 47 further against the regulating surface 33B. This may cause damage to the second bearing 47. In this regard, in the present embodiment, a second gap δ2 is provided between the regulating surface 44A and the inner ring of the second bearing 47. Therefore, even if the first end of the output shaft 44 hits an object, the restricting surface 44B is prevented from coming into axial contact with the inner ring of the 22nd bearing 47. This prevents an overshoot load from being applied to the second bearing 47. In addition, damage to the second bearing 47 can be prevented.
　（１３）駆動プーリ３２Ａに巻かれているベルト３２Ｂの部分の外周面は、第１の貫通孔４１Ｂの径方向外側に位置している。このため、ベルト３２Ｂから発生する摩耗粉などの異物が、径方向外側へ飛散しやすくなる。したがって、異物が突部４１Ｃの内部に侵入することを抑えることができる。 (13) The outer peripheral surface of the portion of the belt 32B wound around the drive pulley 32A is located radially outward of the first through hole 41B. This makes it easier for foreign matter such as wear powder generated by the belt 32B to scatter radially outward. This makes it possible to prevent foreign matter from entering the inside of the protrusion 41C.
　（１４）駆動プーリ３２Ａは、フランジ部３２Ｃを有している。フランジ部３２Ｃは、モータケース４１の端壁に近い側の駆動プーリ３２Ａの軸方向端部の外周面の全周にわたって設けられている。フランジ部３２Ｃの外周面は、駆動プーリ３２Ａに巻かれているベルト３２Ｂの部分の外周面に対して径方向内側に位置する。また、フランジ部３２Ｃの外周面は、駆動プーリ３２Ａに巻かれているベルト３２Ｂの部分の内周面に対して径方向外側に位置する。このため、駆動プーリ３２Ａの第１の端部から第２の端部へ向かう方向のベルト３２Ｂの移動を、フランジ部３２Ｃによって適切に規制することができる。 (14) The drive pulley 32A has a flange portion 32C. The flange portion 32C is provided around the entire outer circumferential surface of the axial end of the drive pulley 32A that is closer to the end wall of the motor case 41. The outer circumferential surface of the flange portion 32C is located radially inward relative to the outer circumferential surface of the portion of the belt 32B wound around the drive pulley 32A. In addition, the outer circumferential surface of the flange portion 32C is located radially outward relative to the inner circumferential surface of the portion of the belt 32B wound around the drive pulley 32A. Therefore, the movement of the belt 32B in the direction from the first end to the second end of the drive pulley 32A can be appropriately restricted by the flange portion 32C.
　＜他の実施の形態＞
　本実施の形態は、つぎのように変更して実施してもよい。
　・大径部４４Ｂを、たとえば、出力軸４４のうちロータコア４５Ａと第２の軸受４７との間の部分にのみ設けるようにしてもよい。この場合、ロータコア４５Ａは、大径部４４Ｂの外周面に装着されない。大径部４４Ｂとロータコア４５Ａとは、軸方向に並んで配置される。 <Other embodiments>
This embodiment may be modified as follows.
The large diameter portion 44B may be provided, for example, only in a portion of the output shaft 44 between the rotor core 45A and the second bearing 47. In this case, the rotor core 45A is not attached to the outer circumferential surface of the large diameter portion 44B. The large diameter portion 44B and the rotor core 45A are arranged side by side in the axial direction.
　・大径部４４Ｂは、出力軸４４と一体的に形成されていなくてもよい。すなわち、大径部４４Ｂは、出力軸４４とは異なる別部材であってもよい。
　・図４に示される第１の構成パターンが採用される場合、突部４１Ｃの先端面が、駆動プーリ３２Ａの第２の端面に対して軸方向に対向する。このため、出力軸４４のストッパ構造において、第２の隙間δ２を第１の隙間よりも小さく設定することに代えて、つぎのようにしてもよい。すなわち、突部４１Ｃの先端面と駆動プーリ３２Ａの第２の端面との間の軸方向隙間を、第１の隙間δ１よりも狭くなるように設定する。このようにすれば、外力によって、出力軸４４が回転角センサ５２Ｃへ向けて軸方向に移動するとき、磁束発生体４８が回転角センサ５２Ｃに接触する前に、駆動プーリ３２Ａの第２の端面が突部４１Ｃの先端面に軸方向に接触する。したがって、外力によって、出力軸４４が軸方向に移動する場合であれ、磁束発生体４８が回転角センサ５２Ｃに軸方向に接触することを抑制することができる。 The large diameter portion 44B does not have to be formed integrally with the output shaft 44. In other words, the large diameter portion 44B may be a separate member from the output shaft 44.
When the first configuration pattern shown in FIG. 4 is adopted, the tip surface of the protrusion 41C faces the second end surface of the drive pulley 32A in the axial direction. Therefore, instead of setting the second gap δ2 smaller than the first gap in the stopper structure of the output shaft 44, the following may be done. That is, the axial gap between the tip surface of the protrusion 41C and the second end surface of the drive pulley 32A is set to be narrower than the first gap δ1. In this way, when the output shaft 44 moves axially toward the rotation angle sensor 52C due to an external force, the second end surface of the drive pulley 32A comes into axial contact with the tip surface of the protrusion 41C before the magnetic flux generator 48 comes into contact with the rotation angle sensor 52C. Therefore, even if the output shaft 44 moves axially due to an external force, it is possible to suppress the magnetic flux generator 48 from coming into axial contact with the rotation angle sensor 52C.
　・伝動機構３２は、ウォーム減速機であってもよい。ウォーム減速機は、ウォームとウォームホイールとを組み合わせた機構である。ウォームは、継手を介して出力軸４４の先端に連結される。継手は、動力伝達部材である。また、変換機構３３は、ラックアンドピニオン機構であってもよい。ラックアンドピニオン機構は、ピニオンシャフトとラック軸とを組み合わせた機構である。転舵シャフト２２は、ラック軸を兼ねる。この場合、ウォームあるいはウォームホイールの摩耗粉、またはウォームあるいはウォームホイールに塗布されるグリースが、第１の貫通孔４１Ｂを介してモータケース４１の内部に侵入するおそれがある。したがって、図３～図５に示される異物の侵入抑制構造の３つの構成パターンのうちいずれか一つを採用することにより、異物がモータケース４１の内部に侵入することを抑制することができる。ただし、突部４１Ｃと駆動プーリ３２Ａとの関係は、突部４１Ｃと継手との関係に読み替える。 The transmission mechanism 32 may be a worm reducer. The worm reducer is a mechanism that combines a worm and a worm wheel. The worm is connected to the tip of the output shaft 44 via a joint. The joint is a power transmission member. The conversion mechanism 33 may also be a rack-and-pinion mechanism. The rack-and-pinion mechanism is a mechanism that combines a pinion shaft and a rack shaft. The steering shaft 22 also serves as the rack shaft. In this case, wear powder from the worm or worm wheel, or grease applied to the worm or worm wheel, may enter the inside of the motor case 41 through the first through hole 41B. Therefore, by adopting any one of the three configuration patterns of the foreign object intrusion prevention structure shown in Figures 3 to 5, it is possible to prevent foreign objects from entering the inside of the motor case 41. However, the relationship between the protrusion 41C and the drive pulley 32A is interpreted as the relationship between the protrusion 41C and the joint.
　・伝動機構３２がウォーム減速機である場合、突部４１Ｃの先端面が、たとえば継手に対して軸方向に対向する。継手は、ウォームと出力軸４４とをつなぎ合わせる部品である。このため、出力軸４４のストッパ構造において、第２の隙間δ２を第１の隙間よりも小さく設定することに代えて、つぎのようにしてもよい。すなわち、突部４１Ｃの先端面と継手との軸方向隙間を、第１の隙間δ１よりも狭くなるように設定する。このようにすれば、外力によって、出力軸４４が回転角センサ５２Ｃへ向けて軸方向に移動するとき、磁束発生体４８が回転角センサ５２Ｃに接触する前に、継手が突部４１Ｃの先端面に軸方向に接触する。したがって、外力によって、出力軸４４が軸方向に移動する場合であれ、磁束発生体４８が回転角センサ５２Ｃに軸方向に接触することを抑制することができる。 - When the transmission mechanism 32 is a worm reducer, the tip surface of the protrusion 41C faces, for example, the joint in the axial direction. The joint is a part that connects the worm and the output shaft 44. Therefore, instead of setting the second gap δ2 smaller than the first gap in the stopper structure of the output shaft 44, the following may be done. That is, the axial gap between the tip surface of the protrusion 41C and the joint is set to be narrower than the first gap δ1. In this way, when the output shaft 44 moves axially toward the rotation angle sensor 52C due to an external force, the joint comes into axial contact with the tip surface of the protrusion 41C before the magnetic flux generator 48 comes into contact with the rotation angle sensor 52C. Therefore, even if the output shaft 44 moves axially due to an external force, it is possible to prevent the magnetic flux generator 48 from coming into axial contact with the rotation angle sensor 52C.
　・製品仕様によっては、モータ３１として、出力軸４４のストッパ構造を割愛した構成を採用してもよい。すなわち、出力軸４４は、大径部４４Ａを有していなくてもよい。第１の隙間δ１と第２の隙間δ２との大小関係を調整する必要もない。 - Depending on the product specifications, the motor 31 may be configured to omit the stopper structure of the output shaft 44. In other words, the output shaft 44 does not need to have a large diameter portion 44A. There is no need to adjust the size relationship between the first gap δ1 and the second gap δ2.
　・図４に示される第１の構成パターン、または第３の構成パターンを採用する場合、駆動プーリ３２Ａとして、第２の外側傾斜面３２Ｄを有さない構成を採用してもよい。モータケース４１が突部４１Ｃを有さない場合に比べて、第１の軸受４６の内部に異物が侵入することを抑制することができる。 - When adopting the first or third configuration pattern shown in FIG. 4, the drive pulley 32A may be configured not to have the second outer inclined surface 32D. This can prevent foreign matter from entering the inside of the first bearing 46, compared to when the motor case 41 does not have the protrusion 41C.
　・製品仕様によっては、モータ３１として、突部４１Ｃを割愛した構成を採用してもよい。この場合、たとえば第１の貫通孔４１Ｂの内径が、駆動プーリ３２Ａの外径Ｄ２と同じになるように設定される。第１の貫通孔４１Ｂの内周面とモータケース４１の端壁外面とが交わる内側角部が、駆動プーリ３２Ａの第２の外側傾斜面３２Ｄと駆動プーリ３２Ａの外周面とが交わる外側角部に対して、軸方向に定められた距離だけ離隔するように設けられる。定められた距離は、たとえば、先の図５に示される第２の外側隙間Ｌ２２と同じ長さである。このようにしても、先の（３），（４），（５）欄に記載の効果と同様の効果を得ることができる。 - Depending on the product specifications, the motor 31 may be configured without the protrusion 41C. In this case, for example, the inner diameter of the first through hole 41B is set to be the same as the outer diameter D2 of the drive pulley 32A. The inner corner where the inner peripheral surface of the first through hole 41B intersects with the outer surface of the end wall of the motor case 41 is provided to be separated from the outer corner where the second outer inclined surface 32D of the drive pulley 32A intersects with the outer peripheral surface of the drive pulley 32A by a predetermined distance in the axial direction. The predetermined distance is, for example, the same length as the second outer gap L22 shown in FIG. 5 above. Even in this case, it is possible to obtain the same effects as those described in sections (3), (4), and (5) above.
　・モータ３１として、突部４１Ｃを割愛した構成が採用される場合、つぎのようにしてもよい。すなわち、第１の貫通孔４１Ｂの内径は、駆動プーリ３２Ａの外径Ｄ２よりも大きくなるように設定される。駆動プーリ３２Ａの第２の端部、たとえば、第１の貫通孔４１Ｂの内部に挿入された状態に維持される。駆動プーリ３２Ａの第２の端部は、モータケース４１の端壁に近い側の軸方向の端部である。第１の貫通孔４１Ｂの内周面は、駆動プーリ３２Ａの外周面に対して、径方向に定められた距離だけ離隔する。定められた距離は、たとえば、先の図５に示される第２の外側隙間Ｌ２２と同じ長さであってもよいし、第２の外側隙間Ｌ２２よりも短い長さであってもよい。このようにしても、先の（６），（７）欄に記載の効果と同様の効果を得ることができる。 - When a configuration in which the protrusion 41C is omitted is adopted as the motor 31, the following may be adopted. That is, the inner diameter of the first through hole 41B is set to be larger than the outer diameter D2 of the drive pulley 32A. The second end of the drive pulley 32A is maintained in a state inserted inside the first through hole 41B, for example. The second end of the drive pulley 32A is the axial end closer to the end wall of the motor case 41. The inner peripheral surface of the first through hole 41B is spaced apart from the outer peripheral surface of the drive pulley 32A by a predetermined distance in the radial direction. The predetermined distance may be, for example, the same length as the second outer gap L22 shown in FIG. 5 above, or may be shorter than the second outer gap L22. Even in this way, the same effects as those described in (6) and (7) above can be obtained.
　なお、製品仕様によっては、駆動プーリ３２Ａの第２の端部を第１の貫通孔４１Ｂの内部に挿入しないようにしてもよい。この場合、第１の貫通孔４１Ｂの内径と、駆動プーリ３２Ａの外径との差は、小さいほどよい。また、モータケース４１の端壁と、駆動プーリ３２Ａの第２の端面との軸方向の距離は、短いほどよい。 Depending on the product specifications, the second end of the drive pulley 32A may not be inserted inside the first through hole 41B. In this case, the smaller the difference between the inner diameter of the first through hole 41B and the outer diameter of the drive pulley 32A, the better. Also, the shorter the axial distance between the end wall of the motor case 41 and the second end face of the drive pulley 32A, the better.
　・転舵機構１１は、電動駆動装置の一例であるが、これに限定されるものではない。電動駆動装置には、モータ３１および伝動機構３２を有する機械装置の全般が含まれる。
　・本明細書において使用される「筒」又は「筒状」という用語は、周壁を有する任意の構造を指しうる。「筒」または「筒状」という用語は、たとえば、円形、楕円形、および鋭いまたは丸い角を持つ多角形の断面形状を有する任意の構造を指しうるが、これらに限定されない。 The steering mechanism 11 is an example of an electric drive device, but is not limited to this. The electric drive device includes any mechanical device having a motor 31 and a transmission mechanism 32.
As used herein, the term "cylinder" or "cylindrical" may refer to any structure having a peripheral wall. The term "cylinder" or "cylindrical" may refer to any structure having a cross-sectional shape, such as, but not limited to, a circle, an oval, and a polygon with sharp or rounded corners.

Claims (9)

  1. 　駆動対象を駆動させるための駆動力を発生するように構成されるモータと、
    　前記モータの駆動力を前記駆動対象に伝達するように構成される伝動機構と、を備え、
    　前記モータは、
    　　軸方向に貫通する貫通孔を有する端壁を含むモータケースと、
    　　前記貫通孔の内周面に非接触状態で前記貫通孔を軸方向に貫通する出力軸であって、前記モータケースの内周面に対して回転可能に支持される出力軸と、を有し、
    　前記伝動機構は、前記モータケースの外側において、前記出力軸に対して一体的に回転可能に連結される筒状の動力伝達部材を有し、
    　前記モータケースは、前記端壁の外面において、前記貫通孔の周囲を囲む筒状の突部を有する電動駆動装置。     A motor configured to generate a driving force for driving a driven object;
    a transmission mechanism configured to transmit a driving force of the motor to the driven object,
    The motor is
    a motor case including an end wall having a through hole extending therethrough in an axial direction;
    an output shaft that passes through the through hole in an axial direction without contacting an inner circumferential surface of the through hole and is supported rotatably with respect to the inner circumferential surface of the motor case,
    the transmission mechanism includes a cylindrical power transmission member that is connected to the output shaft so as to be integrally rotatable with the output shaft outside the motor case,
    The motor case is an electric drive device, and the motor case has a cylindrical protrusion on the outer surface of the end wall that surrounds the periphery of the through hole.
  2. 　前記動力伝達部材は、
    　　前記突部に近い側の軸方向の端面と、
    　　前記端面と前記動力伝達部材の外周面との間の外側角部の全周にわたって設けられる外側傾斜面と、を有し、
    　前記突部の内径は、前記動力伝達部材の外径と同じであり、
    　前記突部の内周面と前記突部の先端面とが交わる内側角部は、前記外側傾斜面と前記動力伝達部材の外周面とが交わる外側角部に対して、軸方向に定められた距離だけ離隔している請求項１に記載の電動駆動装置。     The power transmission member is
    an axial end surface closer to the protrusion;
    an outer inclined surface provided around an outer corner between the end surface and an outer circumferential surface of the power transmission member,
    The inner diameter of the protrusion is the same as the outer diameter of the power transmission member,
    2. The electric drive device according to claim 1, wherein an inner corner where an inner peripheral surface of the protrusion and a tip surface of the protrusion intersect is spaced a predetermined distance in the axial direction from an outer corner where the outer inclined surface and an outer peripheral surface of the power transmission member intersect.
  3. 　前記突部の内径は、前記動力伝達部材の外径よりも大きく、
    　前記動力伝達部材の前記突部に近い側の軸方向の端部は、前記突部に挿入された状態に維持され、
    　前記突部の内周面は、前記動力伝達部材の外周面に対して、径方向に定められた距離だけ離隔している請求項１に記載の電動駆動装置。     The inner diameter of the protrusion is larger than the outer diameter of the power transmission member,
    an axial end portion of the power transmission member that is closer to the protrusion is maintained in a state where it is inserted into the protrusion;
    The electric drive device according to claim 1 , wherein an inner circumferential surface of the protrusion is spaced apart from an outer circumferential surface of the power transmission member by a predetermined distance in the radial direction.
  4. 　前記突部の内径は、前記動力伝達部材の外径よりも小さく、
    　前記突部の先端面は、前記動力伝達部材の前記突部に近い側の軸方向の端面に対して、軸方向に定められた距離だけ離隔している請求項１に記載の電動駆動装置。     The inner diameter of the protrusion is smaller than the outer diameter of the power transmission member,
    The electric drive device according to claim 1 , wherein a tip end surface of the protrusion is spaced a predetermined distance in the axial direction from an end surface of the power transmission member that is closer to the protrusion.
  5. 　駆動対象を駆動させるための駆動力を発生するように構成されるモータと、
    　前記モータの駆動力を前記駆動対象に伝達するように構成される伝動機構と、を備え、
    　前記モータは、
    　　軸方向に貫通する貫通孔を有する端壁を含むモータケースと、
    　　前記貫通孔の内周面に非接触状態で前記貫通孔を軸方向に貫通する出力軸であって、前記モータケースの内周面に対して回転可能に支持される出力軸と、を有し、
    　前記伝動機構は、前記モータケースの外側において、前記出力軸に対して一体的に回転可能に連結される筒状の動力伝達部材を有し、
    　前記動力伝達部材は、
    　　前記端壁に近い側の軸方向の端面と、
    　　前記端面と前記動力伝達部材の外周面との間の外側角部の全周にわたって設けられる外側傾斜面と、を有し、
    　前記貫通孔の内径は、前記動力伝達部材の外径と同じであり、
    　前記貫通孔の内周面と前記端壁の外面とが交わる内側角部は、前記外側傾斜面と前記動力伝達部材の外周面とが交わる外側角部に対して、軸方向に定められた距離だけ離隔している電動駆動装置。     A motor configured to generate a driving force for driving a driven object;
    a transmission mechanism configured to transmit a driving force of the motor to the driven object,
    The motor is
    a motor case including an end wall having a through hole extending therethrough in an axial direction;
    an output shaft that passes through the through hole in an axial direction without contacting an inner circumferential surface of the through hole and is supported rotatably with respect to the inner circumferential surface of the motor case,
    the transmission mechanism includes a cylindrical power transmission member that is connected to the output shaft so as to be integrally rotatable with the output shaft outside the motor case,
    The power transmission member is
    an axial end surface closer to the end wall;
    an outer inclined surface provided around an outer corner between the end surface and an outer circumferential surface of the power transmission member,
    The inner diameter of the through hole is the same as the outer diameter of the power transmission member,
    An electric drive device in which an inner corner where the inner surface of the through hole and the outer surface of the end wall intersect is separated from an outer corner where the outer inclined surface and the outer peripheral surface of the power transmission member by a predetermined axial distance.
  6. 　駆動対象を駆動させるための駆動力を発生するように構成されるモータと、
    　前記モータの駆動力を前記駆動対象に伝達するように構成される伝動機構と、を備え、
    　前記モータは、
    　　軸方向に貫通する貫通孔を有する端壁を含むモータケースと、
    　　前記貫通孔の内周面に非接触状態で前記貫通孔を軸方向に貫通する出力軸であって、前記モータケースの内周面に対して回転可能に支持される出力軸と、を有し、
    　前記伝動機構は、前記モータケースの外側において、前記出力軸に対して一体的に回転可能に連結される筒状の動力伝達部材を有し、
    　前記貫通孔の内径は、前記動力伝達部材の外径よりも大きく、
    　前記動力伝達部材の前記端壁に近い側の軸方向の端部は、前記貫通孔の内部に挿入された状態に維持され、
    　前記貫通孔の内周面は、前記動力伝達部材の外周面に対して、径方向に定められた距離だけ離隔している電動駆動装置。     A motor configured to generate a driving force for driving a driven object;
    a transmission mechanism configured to transmit a driving force of the motor to the driven object,
    The motor is
    a motor case including an end wall having a through hole extending therethrough in an axial direction;
    an output shaft that passes through the through hole in an axial direction without contacting an inner circumferential surface of the through hole and is supported rotatably with respect to the inner circumferential surface of the motor case,
    the transmission mechanism includes a cylindrical power transmission member that is connected to the output shaft so as to be integrally rotatable with the output shaft outside the motor case,
    The inner diameter of the through hole is larger than the outer diameter of the power transmission member,
    an axial end portion of the power transmission member that is closer to the end wall is maintained in a state inserted into the through hole,
    An electric drive device, wherein an inner circumferential surface of the through hole is spaced a predetermined radial distance from an outer circumferential surface of the power transmission member.
  7. 　前記モータは、
    　　前記出力軸を前記モータケースの内周面に対して回転可能に支持するように構成される第１の軸受と、
    　　前記出力軸を前記モータケースの内周面に対して回転可能に支持するように構成される第２の軸受であって、前記第１の軸受よりも前記動力伝達部材から軸方向に離れた位置にある第２の軸受と、
    　　前記出力軸の前記動力伝達部材とは反対側の端部に対して、軸方向に対向するように設けられる回転角センサと、をさらに有し、
    　前記出力軸は、前記第２の軸受の内輪に対して軸方向に対向する大径部を有し、
    　前記大径部と前記内輪との軸方向距離は、前記回転角センサと前記出力軸との軸方向距離よりも短い請求項１～請求項６のうちいずれか一項に記載の電動駆動装置。     The motor is
    a first bearing configured to rotatably support the output shaft relative to an inner circumferential surface of the motor case;
    a second bearing configured to rotatably support the output shaft relative to an inner circumferential surface of the motor case, the second bearing being located axially farther from the power transmission member than the first bearing;
    a rotation angle sensor provided axially opposite to an end of the output shaft on the opposite side to the power transmission member,
    the output shaft has a large diameter portion axially opposed to an inner ring of the second bearing,
    The electric drive device according to any one of claims 1 to 6, wherein an axial distance between the large diameter portion and the inner ring is shorter than an axial distance between the rotation angle sensor and the output shaft.
  8. 　前記伝動機構は、前記動力伝達部材である駆動プーリと、前記駆動プーリによって駆動されるベルトと、を有し、
    　前記駆動プーリに巻かれている前記ベルトの部分の外周面は、前記貫通孔の径方向外側に位置している請求項１～請求項６のうちいずれか一項に記載の電動駆動装置。     the transmission mechanism includes a drive pulley that is the power transmission member, and a belt that is driven by the drive pulley,
    The electric drive device according to any one of claims 1 to 6, wherein an outer circumferential surface of the portion of the belt wound around the drive pulley is located radially outside the through hole.
  9. 　前記伝動機構は、前記動力伝達部材である駆動プーリと、前記駆動プーリによって駆動されるベルトと、を有し、
    　前記駆動プーリは、フランジ部を有し、前記フランジ部は、前記端壁に近い側の前記駆動プーリの軸方向端部の外周面の全周にわたって設けられ、
    　前記フランジ部の外周面は、前記駆動プーリに巻かれている前記ベルトの部分の外周面に対して径方向内側に位置するとともに、前記駆動プーリに巻かれている前記ベルトの部分の内周面に対して径方向外側に位置する請求項１～請求項６のうちいずれか一項に記載の電動駆動装置。     the transmission mechanism includes a drive pulley that is the power transmission member, and a belt that is driven by the drive pulley,
    The drive pulley has a flange portion, and the flange portion is provided over an entire outer circumferential surface of an axial end portion of the drive pulley that is closer to the end wall,
    An electric drive device as described in any one of claims 1 to 6, wherein the outer peripheral surface of the flange portion is located radially inward relative to the outer peripheral surface of the portion of the belt wound around the drive pulley, and is located radially outward relative to the inner peripheral surface of the portion of the belt wound around the drive pulley.
PCT/JP2022/042080 2022-11-11 2022-11-11 Electric drive device WO2024100883A1 (en)

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JPS6268069U (en) * 1985-10-18 1987-04-28
JP2007228689A (en) * 2006-02-22 2007-09-06 Denso Corp Driving method of ac generator for vehicle
JP2012145216A (en) * 2010-12-23 2012-08-02 Jtekt Corp Pulley unit
JP2013090376A (en) * 2011-10-14 2013-05-13 Mitsuba Corp Brushless motor
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JP2016036246A (en) * 2014-07-31 2016-03-17 株式会社デンソー Driving device and electric power steering device using the same
JP2017051050A (en) * 2015-09-04 2017-03-09 株式会社デンソー Driving device and electric power steering device
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JP2020110031A (en) * 2019-01-07 2020-07-16 日立オートモティブシステムズ株式会社 Built-in rotary electric machine

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6268069U (en) * 1985-10-18 1987-04-28
JP2007228689A (en) * 2006-02-22 2007-09-06 Denso Corp Driving method of ac generator for vehicle
JP2012145216A (en) * 2010-12-23 2012-08-02 Jtekt Corp Pulley unit
JP2013090376A (en) * 2011-10-14 2013-05-13 Mitsuba Corp Brushless motor
WO2014054155A1 (en) * 2012-10-04 2014-04-10 三菱電機株式会社 Rotary electric machine having integrated drive control device
JP2016036246A (en) * 2014-07-31 2016-03-17 株式会社デンソー Driving device and electric power steering device using the same
JP2017051050A (en) * 2015-09-04 2017-03-09 株式会社デンソー Driving device and electric power steering device
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