JP4811707B2 - Rotating electric machine - Google Patents

Description

  The present invention relates to a rotating electrical machine, and more particularly to an improvement in a stator fixing structure of an EPS motor.

Various motors such as stepping motors have been proposed as rotating electric machines. When constructing a stator of this type of motor, for example, a coil is wound around a stator core laminated by boss caulking, welding, etc., and the stator core on which the coil is wound is press-fitted into a motor case and fixed or sintered. A method of fixing by fitting is generally employed (see Patent Document 1).

  However, in the conventional method, when the stator core is press-fitted into the motor case, the stator core directly contacts the motor case, and thus the stator core may be distorted. When the stator core is distorted, in particular, in the case of a stator constituting an EPS (electric power steering apparatus) motor, it becomes a factor of deteriorating loss torque and loss torque fluctuation affecting the handle return performance of the electric power steering. Further, since the stator core is in direct contact with the motor case, when the motor is energized, the exciting force in the radial direction of the stator core may be transmitted to the motor case, increasing noise and vibration.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to prevent the stator core from being distorted when the stator core is press-fitted into the motor case, and to prevent the stator core from being deformed during energization. This is to prevent the excitation force generated in the direction from being transmitted to the motor case.

In order to achieve the above object, the present invention comprises a motor case formed in a cylindrical shape, and a stator core that is disposed on the inner peripheral side of the motor case with an interval and wound with a coil, In order to reduce noise and vibration generated from a rotating electrical machine, an elastic member made of, for example, rubber, resin, or mold is inserted as a damping member between the stator core and the motor case when configuring the electrical machine. Further, annular grooves are formed at two locations on the outer peripheral side of the stator core so as to be spaced apart from each other in the direction of the rotation axis. A fixing ring is mounted on each of the annular grooves, and a part of the fixing ring serves as a projecting portion. The stator core protrudes from the groove, and constitutes a rotating electrical machine that is fixed to the motor case via the protruding portion of the fixing ring.
Further, the fixing ring is configured as a C-ring having an abutment portion, and a flat portion that can be in close contact with the bottom of the annular groove is formed on the inner peripheral side of the abutment portion, and the stator core and the motor case An elastic member was inserted between the two fixing rings respectively mounted in the two annular grooves in the gap between the two.

  According to the above-described means, the stator core is fixed to the motor case via the protruding portion of the fixing ring, and the stator core and the motor case are not in direct contact with each other, so that the stator core is distorted when the stator core is press-fitted into the motor case. Can be prevented, and the cause of loss torque and loss torque fluctuation can be reduced. Furthermore, it is possible to prevent the excitation force generated in the circumferential direction of the stator core from being transmitted to the motor case during energization, and to reduce noise and vibration generated from the rotating electrical machine.

  According to the present invention, it is possible to reduce the cause of loss torque and loss torque fluctuation, and it is possible to reduce noise and vibration generated from the rotating electrical machine.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an EPS motor showing a first embodiment of the present invention. In FIG. 1, an EPS motor 10 is mounted as a rotating electric machine for an electric power steering apparatus, and a motor case 12 formed in a substantially bowl shape, and mounted on the opening side of the motor case 12 so as to close the opening of the motor case 12. The bracket 14, an annular stator core 16 fixed to the inner peripheral surface of the motor case 12, a plurality of coils 18 wound around the stator core 16, and a rotor 20 are configured.
The rotor 20 includes a shaft 22 rotatably disposed in the motor case 12, an annular rotor core 24 fixed to the outer peripheral surface of the shaft 22, a magnet 26 fixed to the outer peripheral surface of the rotor core 24, and a magnet 26 And an annular rotor cover 28 that covers the magnet 26 and is mounted on the outer peripheral surface of the motor.
The shaft 22 for transmitting torque is rotatably supported at one end in the axial direction by a bearing (bearing) 30 attached to the recess 14a of the bracket 14, and the other end in the axial direction is supported by the motor case 12. Is rotatably supported by a bearing 32 mounted in the recess 12a. A boss 34 is connected to a portion of the shaft 22 that protrudes to the outside from the bracket 14 via the bearing 30, and a resolver rotor 36 is disposed in the vicinity of the bearing 30. A resolver stator 38 is disposed in the vicinity of the resolver rotor 36, and the resolver stator 38 is fixed to the terminal block 40. A grommet 42 is mounted in the through hole 12 b formed on the bottom side of the motor case 12, and a lead wire 44 for energizing the coil 18 is inserted into the grommet 42.
The stator core 16 is integrally formed in an annular shape using, for example, a magnetic material as one element of the stator, and a plurality of coils 18 are wound thereon. When the stator core 16 is composed of split cores, teeth 46 are formed on the split cores as shown in FIG. In this case, the teeth 46 are arranged at equal intervals along the circumferential direction on the inner peripheral side of the stator core 16, and coil windings (not shown) constituting the coil 18 are wound around the teeth 46. Yes. In other words, a rotating magnetic field for rotating the rotor 20 is formed in the stator core 16 by sequentially energizing the coils 18 of the teeth 46.

Two annular annular grooves 48 are formed on the outer peripheral surface of the stator core 16 so as to be separated from each other, and a fixing ring 50 is mounted in each annular groove 48. The fixing ring 50 is mounted in the annular groove 48 with a part thereof (a part in a direction orthogonal to the longitudinal direction) protruding from the annular groove 48 as a protruding portion. That is, the stator core 16 is fixed to the motor case 12 via the protrusion of the fixing ring 50, and the stator core 16 and the motor case 12 are not in direct contact with each other.
As shown in FIG. 3, the fixing ring 50 is configured as a C-ring having fitting portions 52 and 54, and as shown in FIG. 4, the stator core 16 is disposed on the inner peripheral side of the fitting portions 52 and 54. Flat portions (straight portions) 52a and 54a that can be in close contact with the bottom surface 48a of the annular groove 48 are formed.
When configuring the stator, an insulator 56 is inserted between the teeth 46 of the stacked stator cores 16, coil windings of the coils 18 are wound around the teeth 46, and a fixing ring 50 is placed in each annular groove 48 of the stator core 16. Fit and fit. Thereafter, the stator core 16 to which the coil 18 and the fixing ring 50 are attached is press-fitted into the inner peripheral side of the motor case 12 to fix the stator core 16 to the motor case 12. At this time, the stator core 16 is fixed to the motor case 12 via the protruding portion of the fixing ring 50 without the stator core 16 and the motor case 12 being in direct contact.
At this time, the fixing ring 50 functions as a stopper for the stator core 16 because the abutment portions 52 and 54 close to each other and the flat portions 52a and 54a are in close contact with the bottom of the annular groove 48.
According to this embodiment, since the stator core 16 and the motor case 12 are not in direct contact with each other, it is possible to prevent the stator core 16 from being distorted when the stator core 16 is press-fitted into the motor case 12. The cause of loss torque and loss torque fluctuation can be reduced. Further, since the stator core 16 and the motor case 12 are not in direct contact with each other, it is possible to prevent the excitation force generated in the circumferential direction of the stator core 16 from being transmitted to the motor case 12 when energized. Noise and vibration generated from the motor 10 can be reduced.
Next, a second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, an elastic member made of, for example, rubber, resin, or a mold is inserted as a vibration damping member 58 into the gap between the stator core 16 and the motor case 12. It is the same as that of an Example.

According to this embodiment, since the stator core 16 and the motor case 12 are not in direct contact with each other, it is possible to prevent the stator core 16 from being distorted when the stator core 16 is press-fitted into the motor case 12. In addition to reducing the loss torque and the cause of loss torque fluctuation, it is possible to prevent the excitation force generated in the circumferential direction of the stator core 16 from being transmitted to the motor case 12 during energization, and is generated from the EPS motor 10. Noise and vibration can be reduced.
Furthermore, since the damping member 58 inserted between the stator core 16 and the motor case 12 absorbs noise and vibration generated from the EPS motor 10, the noise and vibration generated from the EPS motor 10 can be further reduced. .

Moreover, as the stator core 16, teeth and back motor core casing are integrated, Antipodes divided core, back motor case and core teeth is divided, using any of the core skew laminated core or sintered core, be able to.

  Further, when the fixing ring 50 is mounted on the stator core 16, the fixing ring 50 is adhered to the annular groove 48 with an adhesive while leaving a gap between the fitting portion 52 and the fitting portion 54 of the fixing ring 50. Can also be adopted.

1 is a cross-sectional view of an EPS motor showing a first embodiment of the present invention. The top view which shows the relationship between the stator core using a split core, and a fixing ring. The top view of a fixing ring. The enlarged side view of the fitting part of a fixing ring. Sectional drawing of the EPS motor which shows 2nd Example of this invention. The principal part cross-sectional perspective view of an EPS motor. The principal part expanded sectional view which shows the state which inserted the damping member between the stator core and the motor case.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 EPS motor 12 Motor case 14 Bracket 16 Stator core 18 Coil 20 Rotor 48 Annular groove 50 Fixing ring 52, 54 Mating part 58 Damping member

Claims (3)

A motor case formed into a cylindrical shape, said stator core are spaced on the inner diameter side of the motor case by a coil is a winding, and a damping material inserted between said stator core and said motor case With
On the outer peripheral side of the stator core, annular grooves are formed at two locations spaced apart from each other in the rotation axis direction. A fixing ring is attached to each of the annular grooves, and a part of the fixing ring serves as a projecting portion. Protruding from the groove, the stator core is fixed to the motor case via the protruding portion of the fixing ring,
The fixing ring is configured as a C-ring having an abutment portion, and a flat portion that can be in close contact with the bottom of the annular groove is formed on the inner peripheral side of the abutment portion,
An electrical rotating machine according to claim 1, wherein an elastic member is inserted between the two fixing rings respectively mounted in the two annular grooves in the gap between the stator core and the motor case . In the rotating electrical machine according to claim 1 ,
The rotating ring is configured as a C-ring having an abutment portion, and is bonded to the annular groove with the abutment portion as a gap. In the rotating electrical machine according to claim 1 or 2,
The stator core is constituted by a core in which a tooth and a back motor case are integrated, a die division core, a core in which a back motor case and a tooth are divided, a skew laminated core, or a sintered core. Rotating electric machine.

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