JP4725293B2 - Motor unit - Google Patents

Description

  The present invention relates to a motor unit that includes a motor that is a drive source and a speed change mechanism that changes the driving force of the motor.

  Conventionally, an electric power steering unit has been applied as an assist in operating a steering in a vehicle. A motor (hereinafter referred to as “EPS motor”) that is a drive source of the electric power steering unit includes a resolver for detecting a rotational position (see Patent Document 1 and Patent Document 2).

  In the EPS motors described in Patent Document 1 and Patent Document 2, the resolver rotor is disposed in the vicinity of the output end of the output shaft (drive shaft) of the EPS motor, and the resolver rotor attached to the output shaft side rotates. The signal is detected by a resolver detector arranged corresponding to the outer periphery of the resolver rotor, and a detection signal of the resolver detector is sent as an electrical signal to a controller or the like outside the EPS motor via a resolver harness.

On the other hand, there is a structure in which the resolver is attached not to the output end of the drive shaft but to the end opposite to the output end (hereinafter referred to as a modified structure).
JP 2004-322814 A JP 2002-354755 A

  However, in the above-mentioned Patent Document 1 or Patent Document 2, or an EPS motor having a deformed structure, the resolver is present as at least a part of the EPS motor, so that the work efficiency during assembly is poor. In addition, the motor yoke length or the transmission mechanism shaft length may be extended, which may hinder downsizing in terms of layout and may not meet the demand for compactness.

  In addition, the harness must be routed from the resolver detector provided inside the EPS motor, and many plugs for ensuring waterproofness must be provided.

  Furthermore, a resolver cover is required separately from the motor yoke, and a waterproof seal or the like for the cover is required, resulting in complication.

  In view of the above facts, the present invention provides a motor unit that has a simple structure, reduces the wiring of the harness with respect to the resolver, does not require waterproofing, and can reliably detect the rotational state of the motor. Is the purpose.

The present invention provides a motor having a driving force generator in a sealed space and a driving force generated by the driving force generator via a driving shaft projecting from the motor to shift the driving force. a mechanism, in a motor unit configured, provided the speed change mechanism side in which the drive shaft is connected, and the resolver stator surrounding the axial end portion of the shaft drive that protrudes from the front SL motor, A resolver rotor, which is attached to a drive shaft surrounded by the resolver stator and serves as a reference for detecting the rotational position of the drive shaft, is disposed on an inner peripheral surface of the resolver stator, and a gap between the resolver stator and the resolver rotor. And a resolver detector that detects the rotational position of the drive shaft from the change.

  According to the present invention, since the resolver detection unit and the resolver rotor are disposed outside the motor unit, it is possible to increase the degree of freedom of the harness wiring between the resolver detection unit and, for example, the controller. Further, by reducing the number of parts in the motor unit, it is possible to reduce the size of the driving force generation unit (for example, shorten the motor yoke length).

  Furthermore, since the speed change mechanism portion rotates in the same direction as the drive shaft from the motor, the rotational state of the motor can be reliably detected even if a resolver detection portion is provided on the speed change mechanism portion side.

The present invention is an axial end diameter of the drive shaft projecting from the front SL motor, the resolver rotor on the outer peripheral side of the axial end portion which is the diameter is formed, the axial end which is the diameter A female serration connected to the driven shaft on the transmission mechanism side may be formed on the inner peripheral side of the part.

  As a structure for connecting the motor drive shaft to the driven shaft on the transmission mechanism side, the axial end of the motor drive shaft is expanded, and a female serration is formed on the inner peripheral side of the expanded axial end. Therefore, the resolver can be arranged in a narrow space by being able to be reliably connected to the driven shaft on the transmission mechanism side, and by forming the outer peripheral side of the expanded axial end portion suitable for the resolver rotor. can do.

  As described above, the present invention has an excellent effect that it is simple in structure, reduces the wiring of the harness with respect to the resolver, does not require waterproofing, and can reliably detect the rotation state of the motor. Have.

  FIG. 1 shows an electric power steering motor (EPS motor) 10 according to the present embodiment.

  As for the EPS motor 10, the main components are accommodated in the cylindrical case 12, and the internal space is almost sealed.

  A rotor shaft 14, which will be described later, protrudes from an end surface of the case 12 (left end surface in FIG. 1).

  Further, a front bracket 16 bent in a direction orthogonal to the rotor shaft 14 is provided on the left end side (opening side) of the case 12 in FIG. 1. In the present embodiment, the front bracket 16 has a circular shape. A plate-like motor flange portion 18 is attached by bolts 19. Therefore, the EPS motor 10 and the motor flange portion 18 are integrated, and the left end side (opening side) of the case 12 in FIG. 1 is closed by the motor flange portion 18 so that the internal space of the case 12 is substantially sealed. It is said that.

  The motor flange portion 18 has a role of connecting and fixing to the gear box unit 50 that is a speed change mechanism portion.

  The rotor shaft 14 is rotatably supported by bearings 20 provided at the left and right ends of FIG. 1 of the case 12. The rotor shaft 14 is fitted inside the case 12 to the rotor core 23 of the rotor 22, and outside the case 12. A driven shaft 52 protruding from the gear box unit 50 side is connected in a coaxial state.

  A stator 24 is attached to the inner peripheral surface of the case 12 so as to face the permanent magnet 25 fixed to the outer peripheral surface of the rotor core 23, and is opposed to the outer peripheral surface of the rotor 22. A stator coil 24 </ b> A is wound around the stator 24.

  The stator 24 and the rotor 22 are configured as one element of a driving force generation unit of the motor 10, and by causing a change in magnetic field between the stator 24 and the rotor 22, both of them are relatively rotated (substantially) , The rotor 22 rotates), and this rotational driving force can be output to the outside (for example, a gear box) via the rotor shaft 14.

  Further, a resin mold body (not shown) is detachably disposed at the other inner end of the case 12 (the right end in FIG. 1). A substrate (not shown) on which an electrical component for controlling the driving of the rotor 22 is mounted is mounted on the resin mold body, and electrical connection with the outside is made via a connection terminal provided on the substrate. (Electric power for energizing the stator coil 24A, etc.) is provided.

  Here, the motor flange portion 18 has a structure in direct contact with the case 12, and has an arrangement structure that easily receives heat in the inner space of the case 12.

  Therefore, it is possible to eliminate the overheating state of the inner space of the case 12 by absorbing heat by the motor flange portion 18 while maintaining the substantially sealed structure of the case 12.

  Here, the rotor shaft 14 applied as transmission of the driving force between the EPS motor 10 and the gear box unit 50 is connected to the driven shaft 52 protruding from the gear box unit 50 in a coaxial state.

  In this case, the connecting side end (axial end) of the rotor shaft 14 to the driven shaft 52 is enlarged in diameter, and the resolver rotor 54 is disposed on the outer peripheral side of the enlarged axial end (longitudinal end). A circular groove 56 serving as a female serration is formed on the inner peripheral side (center portion) of the axial end portion in which the diameter is increased.

  On the other hand, an osserration is formed on the outer periphery of the distal end of the driven shaft 52 on the gear box unit 50 side, and the oscillation is engaged with the female serration of the rotor shaft 14, whereby the driving force of the rotor shaft 14 is increased. It is reliably transmitted to the driven shaft 52 on the gear box unit 50 side. The driven shaft 52 is rotatably supported by the gear housing 53 by a bearing 55, and a worm 57 is formed at a substantially intermediate portion of the driven shaft 52. A worm wheel 59 is engaged with the worm 57. The output shaft 62 of the worm wheel 59 is connected to an input shaft coupled to the steering wheel.

  Further, the outer periphery of the resolver rotor 54 has a shape suitable for rotational position detection by a resolver detection unit 58 described later, and has an elliptical shape shown in FIG. 2A and a rectangular shape shown in FIG. Square), the triangular state shown in FIG. 2C is a typical shape.

  The resolver rotor 54 is surrounded by a resolver stator 60 provided in the gear box unit 50. The resolver stator 60 is formed in an annular shape and is disposed with a gap between the resolver rotor 54 and the resolver rotor 54 does not interfere with the inner periphery of the resolver stator 60 even when the rotor shaft 14 rotates. It is like that.

  The inner periphery of the resolver stator 60 is a resolver detector 58 that constitutes a resolver together with the resolver rotor 54. That is, the resolver rotor 54 and the resolver detection unit 58 are opposed to each other when the EPS motor 10 and the gear box unit 50 are connected and fixed by the motor flange unit 18, so that the resolver rotor 54 and the resolver stator are opposed to each other. A structure in which the resolver detection unit 58 can detect the rotation state of the resolver rotor 54 (that is, the rotation state of the rotor shaft 14) as the reluctance of the gap with the rotor 60 changes depending on the rotation angle position of the resolver rotor 54. It is.

  The operation of this embodiment will be described below.

  Before the EPS motor 10 and the gear box unit 50 are connected and fixed, the resolver (resolver rotor 54, resolver detection unit 58) of the resolver rotor 54 is disposed on the EPS motor 10 side, and the resolver detection unit 58 is the gear box unit. Since it is arranged on the 50 side, it does not function at all.

  From this state, the EPS motor 10 and the gear box unit 50 are connected and fixed by the motor flange portion 18.

  At this time, since the female serration formed in the central portion of the resolver rotor 54 in the rotor shaft 14 and the male serration formed in the driven shaft 52 on the gear box unit 50 side are fitted together, the rotor shaft 14 and the driven shaft 52 are coaxially connected.

  In the state where the connection is completed, the resolver rotor 54 is accommodated in a state surrounded by the resolver stator 60 of the gear box unit 50, and faces the resolver detection unit 58 located on the inner peripheral surface of the resolver stator 60. As shown in FIGS. 2A to 2C, the outer periphery of the resolver rotor 54 has a shape (ellipse, rectangle, triangle) suitable for rotational position detection by the resolver detector 58, so that the rotor shaft 14 is When rotated, the rotational state can be detected by the resolver detector 58.

  Thus, since the resolver rotor 54 and the resolver detection part 58 are arrange | positioned outside the case 12 of the EPS motor 10, the sealing performance of the EPS motor 10 improves.

  Further, since the resolver is positioned on the resolver stator 60 of the gear box unit 50, the yoke length of the EPS motor 10 can be shortened, and the overall size can be reduced.

  Furthermore, the harness wiring from the resolver detection unit 58 to the controller can be easily routed, and a waterproof seal can be easily constructed to improve the assembling workability.

It is a longitudinal cross-sectional view of the EPS motor and gearbox unit which concern on this Embodiment. It is a front view of the shape of a resolver rotor, (A) is elliptical shape, (B) is a rectangular shape, (C) is a triangular shape.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 EPS motor 12 Case 14 Rotor shaft 16 Front bracket 18 Flange 20 Bearing 22 Rotor 24 Stator 24A Stator coil 50 Gear box unit 52 Drive shaft 54 Resolver rotor 56 Circular groove 58 Resolver detection part 60 Resolver stator

Claims (1)

A motor having a driving force generator in a sealed space, a transmission mechanism that receives the driving force generated by the driving force generator through a driving shaft protruding from the motor, and shifts the driving force; A motor unit comprising:
A resolver stator that is provided on the side of the speed change mechanism connected to the drive shaft and surrounds the axial end of the drive shaft protruding from the motor;
A resolver rotor attached to a drive shaft surrounded by the resolver stator and serving as a reference for detecting the rotational position of the drive shaft;
A resolver detector that is disposed on an inner peripheral surface of the resolver stator and detects a rotational position of the drive shaft from a change in a gap between the resolver stator and the resolver rotor;
Have
The axial end portion of the drive shaft protruding from the motor is expanded in diameter, the resolver rotor is formed on the outer peripheral side of the expanded axial end portion, and the inner peripheral side of the expanded axial end portion The motor unit is characterized in that a female serration connected to the driven shaft on the transmission mechanism side is formed.

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