JP2007135296A - Dynamo-electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of a strange sound accompanying the vibration of a rotor. <P>SOLUTION: This dynamo-electric machine is equipped with: a shaft 18 which is arranged rotatably; a rotor 20 which is fixed to the periphery of the shaft 18; a motor case 12 which houses the rotor 20; a stator 16 which is fixed to the motor case 12, being arranged outside the rotor 20; and a front bearing 34 and a rear bearing 36 which support the shaft 18 rotatably, being fixed to a flange 14 or the motor case 12. The bearing 34 is made larger than the bearing 36, with its inner gap in radial direction smaller than the bearing 36. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rotating electrical machine, and more particularly, to an improvement in a bearing that rotatably supports a shaft fixed to a rotor of an EPS motor.

Conventionally, various motors such as an EPS motor used in an electric power steering apparatus that assists an operation force of a steering wheel of a vehicle have been proposed as a rotating electric machine. Among these types of motors, EPS motors are particularly required to be quiet, and the noise of the entire system is reduced by reducing the noise of the motor that is the excitation source. For example, in order to reduce noise caused by vibration of the rotor, a structure in which a pressure is applied to a bearing (bearing) that rotatably supports the rotor shaft in a state where the magnetic center of the rotor is shifted using a spring washer is generally used. It has been adopted. In addition, in order to reduce the impact noise caused by the vibration of the amateur, a collision preventing member is provided between the outer ring of the bearing and the bearing housing to secure a clearance between the outer ring of the bearing and the bearing housing to prevent the collision. The thing is also proposed (refer patent document 1).
JP 2000-166169 A

  However, in an EPS motor with a high load, even if it is attempted to suppress the vibration of the rotor only by a structure that applies a pressure to the bearing, the loss torque may increase as the movement of the bearing is hindered.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to prevent the generation of abnormal noise accompanying the vibration of the rotor.

  To achieve the above object, the present invention provides a shaft that is rotatably arranged, a rotor fixed to the outer periphery of the shaft, a housing that houses the rotor, and an outer peripheral side of the rotor. A stator fixed to the housing, and a plurality of bearings fixed to the housing and rotatably supporting both end sides of the shaft, and the inner clearance in the radial direction of one of the plurality of bearings is set to the other The rotating electrical machine is configured to be smaller than the internal clearance in the radial direction of the bearing.

  According to this configuration, by reducing the internal clearance in the radial direction of one of the plurality of bearings to be smaller than the internal clearance in the radial direction of the other bearing, the vibration of the rotor is reduced and the noise of the rotor is abnormal. Can be prevented. In particular, when a deep groove ball bearing is used as the bearing, since it has some bearing rigidity not only in the radial direction but also in the axial direction, not only can radial vibration be reduced by narrowing the radial internal clearance, Axial vibration can also be reduced.

  When configuring the rotating electrical machine, a configuration in which one bearing is formed larger than the other bearing is adopted, or one bearing is formed larger than the other bearing, and the radial direction of the bearing It is also possible to adopt a configuration in which the internal gap in is smaller than the internal gap in the radial direction of the other bearing.

  Further, the bearing having the smaller internal clearance in the radial direction or the bearing having the larger size is used as a front bearing, and the front end of the shaft protruding from the housing is rotatably supported, and the other As the bearing on the rear side, a configuration in which the end side of the shaft is rotatably supported can be employed. In this case, since the bearing on the front side serves as a fulcrum, the displacement of the precession can be suppressed even if the shaft runout due to an external force or the like occurs, so that the shaft runout on the output side of the shaft can be reduced. Further, if the front side bearing is made larger than the rear side bearing, the bearing rigidity increases, so that durability against a high load received from the front side (output side) is improved. As a result, it is possible to prevent the bearing life from being shortened and to prevent the generation of abnormal noise due to indentation or damage.

  According to the present invention, it is possible to prevent abnormal noise from being 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 a rotating electric machine for an electric power steering device, and has a motor case (yoke) 12 formed in a substantially bowl shape, and closes the opening of the motor case 12 on the opening side of the motor case 12. , A stator 16 fixed to the motor case 12, a shaft 18 rotatably arranged, and a rotor 20 fixed to the outer periphery of the shaft 18. The motor case 12 and the flange 14 are configured as a housing, and the stator 16 and the rotor 20 are accommodated in the housing.

  The stator 16 includes an annular stator core 22 fixed to the inner peripheral surface of the motor case 12, a plurality of coils 24 wound around the stator core 22, and an insulator 26 disposed around each coil 24. Has been. The stator core 22 is integrally formed in an annular shape using, for example, a magnetic material, and a plurality of coils 24 are wound around it. The stator core 22 can also be constituted by a split core.

  The rotor 20 includes an annular rotor core 28 fixed to the outer peripheral surface of the shaft 18, a magnet 30 fixed to the outer peripheral surface of the rotor core 28, and an annular rotor that is attached to the outer peripheral surface of the magnet 30 and covers the magnet 30. A cover 32 is provided.

  The shaft 18 for transmitting torque is rotatably supported at one end in the axial direction by a bearing 34 that is mounted in the recess 14 a 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 36 mounted in the recess 12a. The bearing 34 is formed larger than the rear side (terminal side) bearing (bearing) 36 as a front side (output side) bearing, and has an internal clearance (radial internal clearance) in the radial direction from the bearing 36. Is also formed small.

  The EPS motor 10 in this embodiment is an inner rotor type brushless motor, and a boss 38 is connected to a portion of the shaft 18 protruding from the bracket 14 through the bearing 34 to the outside, and a resolver rotor is provided in the vicinity of the bearing 34. 40 is arranged. A resolver stator 42 is disposed in the vicinity of the resolver rotor 40, and the resolver stator 42 is fixed to a terminal block 44.

  The resolver stator 42 is provided corresponding to, for example, the U, V, and W phases, and detects the rotational position of the rotor 20 in response to changes in the magnetic poles of the resolver rotor 40 accompanying the rotation of the rotor 20. Yes.

  A grommet 46 is mounted in the through hole 12 b formed on the bottom side of the motor case 12, and a lead wire 48 for energizing the coil 24 is inserted into the grommet 46.

  According to the present embodiment, the bearing 34 is formed larger than the rear side (terminal side) bearing (bearing) 36 as a front side (output side) bearing, and an internal gap in the radial direction (radial internal gap). ) Is made smaller than the bearing 36, so that vibration of the rotor 20 can be suppressed without applying excessive pressure, and a high load can be dealt with. Generation of abnormal noise (noise) can be prevented.

  Further, when deep groove ball bearings are used as the bearings 34 and 36, the bearings have some bearing rigidity not only in the radial direction but also in the axial direction. In addition, axial vibrations can also be reduced.

  Furthermore, since one bearing 34 is formed larger than the other bearing 36, the front bearing 34 serves as a fulcrum when the shaft 18 rotates, so even if shaft runout due to external force or the like occurs, Since the displacement of the differential motion can be suppressed, the shaft runout on the output side of the shaft 18 can be reduced. Further, if the front side bearing 34 is made larger than the rear side bearing 36, the bearing rigidity is increased, so that durability against a high load received from the front side (output side) is improved. As a result, it is possible to prevent the bearing (bearing) life from being shortened and to prevent the generation of abnormal noise due to indentation or damage.

  Moreover, in the said Example, only the structure which forms the bearing 34 as a front side (output side) bearing larger than the rear side (terminal side) bearing (bearing) 36 is also employable. In this case, since the bearing 34 on the front side serves as a fulcrum, even if shaft runout due to external force or the like occurs, shaft runout on the output side of the shaft 18 can be reduced.

  Further, as the stator core 22, any of a core in which the teeth and the back yoke are integrated, a die split core, a core in which the back yoke and the teeth are split, a skew laminated core, or a sintered core can be used. .

1 is a cross-sectional view of an EPS motor showing a first embodiment of the present invention.

Explanation of symbols

10 EPS motor 12 Yoke 14 Flange 16 Stator 18 Shaft 20 Rotor 22 Stator core 28 Rotor core 34, 36 Bearing

Claims (5)

A shaft arranged rotatably, a rotor fixed to the outer periphery of the shaft, a housing for housing the rotor, a stator arranged on the outer peripheral side of the rotor and fixed to the housing, and fixed to the housing A plurality of bearings rotatably supporting both ends of the shaft, and the internal clearance in the radial direction of one of the plurality of bearings is made smaller than the internal clearance in the radial direction of the other bearing. Rotating electric machine. A shaft arranged rotatably, a rotor fixed to the outer periphery of the shaft, a housing for housing the rotor, a stator arranged on the outer peripheral side of the rotor and fixed to the housing, and fixed to the housing And a plurality of bearings rotatably supporting both ends of the shaft, wherein one of the plurality of bearings is formed larger than the other bearing. A shaft arranged rotatably, a rotor fixed to the outer periphery of the shaft, a housing for housing the rotor, a stator arranged on the outer peripheral side of the rotor and fixed to the housing, and fixed to the housing And a plurality of bearings rotatably supporting both ends of the shaft, wherein one of the plurality of bearings is formed larger than the other bearing, and an internal gap in the radial direction of the bearing Is a rotating electrical machine made smaller than the internal clearance in the radial direction of the other bearing. 4. The rotating electrical machine according to claim 1, wherein the bearing having the smaller internal clearance in the radial direction is a front-side bearing that rotatably supports a tip side of the shaft protruding from the housing, The rotary electric machine is a rotating electric machine characterized in that the rear end side of the shaft is rotatably supported as a rear side bearing. 4. The rotating electrical machine according to claim 2, wherein the large-sized bearing is a front-side bearing that rotatably supports a tip side of the shaft protruding from the housing, and the other bearing. The rotary electric machine is characterized in that the end side of the shaft is rotatably supported as a rear side bearing.

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