JP2007181292A - Stator core of rotary electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the stator core of a rotary electric machine in which electromagnetic sound is reduced. <P>SOLUTION: The stator core 2 of a rotary electric machine comprises a plurality of tooth portions 6 extending toward the center of a rotating shaft, an annular yoke 7 located on the outside of the plurality of tooth portions 6 and connecting them, and fillers 8, 10, 12 for filling slits provided in the yoke 7 along the outline thereof. Preferably, the central portion of the slit is narrower than the opposite end portions. On the outside of the slit in the yoke 7, holes 14, 16, 18 for inserting bolts in order to secure the stator core to the housing are provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a stator core of a rotating electrical machine, and more particularly to a stator core of a vehicle-mounted rotating electrical machine.

  In recent years, there has been a demand for a small and efficient motor as a drive motor for electric vehicles and hybrid vehicles. In vehicular rotating electrical machines such as motors and generators, it is preferable that electromagnetic noise generated from the rotating electrical machines be reduced as much as possible in order to make use of the quietness characteristic of electric vehicles.

Japanese Laid-Open Patent Publication No. 5-21733 (Patent Document 1) discloses an automotive alternator in which a plurality of notches are provided in a slot portion of a stator, and a viscoelastic body is provided between the outer periphery of the stator core and the inner periphery of the bracket. A technique for reducing magnetic noise by inserting
Japanese Patent Application Laid-Open No. 5-21733 JP-A-5-83901 JP-A-3-230744 JP 2002-218725 A

FIG. 6 is a diagram for explaining the excitation force of the permanent magnet motor.
FIG. 6 shows the excitation force gain in the case of an 8-pole motor. The teeth of the stator of the permanent magnet motor generate an excitation force having a rotational order that is an integral multiple of the number of poles of the rotor magnet. As can be seen from FIG. 6, in the case of an 8-pole motor, there are peaks of the 8th, 16th, 24th, 32nd, 40th, 48th, and 56th excitation forces. That is, in the 8-pole motor, there is a peak of the excitation force in the order of an integer multiple of 8.

  FIG. 7 is a diagram showing changes in the excitation force with respect to the position of the stator teeth at times t1, t2, and t3.

  As shown in FIG. 7, in the 48th-order component of rotation, a positive excitation force is applied to all 48 stator teeth at time t1. At time t2, the excitation force applied to the center portion of the stator teeth is 0, and at time t3, the same force in the negative direction is applied to each of the 48 teeth.

  On the other hand, in the rotational eighth-order component, an excitation force is applied in the reverse direction every three teeth at each time t1, t2, and t3. That is, the rotating eighth-order component cancels out the stator teeth as a whole and is less likely to generate vibration.

  That is, it can be said that the excitation force of the rotation order of the total number of stator teeth (48th order in FIG. 7) acts on each tooth in the same phase and thus easily vibrates. For example, a 48-tooth stator generates a 48th-order vibration.

  Due to such high-order vibrations, the electromagnetic noise of a motor for a vehicle is particularly problematic in the range of 300 Hz to 5 kHz.

In order to reduce such electromagnetic noise, it is effective to take measures to cause the elastic body to absorb vibration.
However, as in the technique disclosed in Japanese Patent Application Laid-Open No. 5-21733 (Patent Document 1), the method of inserting a viscoelastic body lacks ease of assembly. Furthermore, since the thickness of the viscoelastic body cannot be arbitrarily changed, the width of the vibration frequency that can be absorbed is narrowed.

  In addition, when the stator core is fastened to the bracket, even if a viscoelastic body is inserted between the core and the case, vibration that propagates from the bolt to the entire transaxle cannot be suppressed.

  An object of the present invention is to provide a stator core of a rotating electrical machine with reduced electromagnetic noise.

  In summary, the present invention is a stator core of a rotating electrical machine, a plurality of teeth portions extending toward the center of the rotation axis, an annular yoke portion that is located outside the plurality of teeth portions and connects the plurality of teeth portions; The yoke portion includes a filler filled in a slit provided along the outer shape of the yoke portion.

  Preferably, the slit has a first portion and a second portion that is narrower than the first portion.

  Preferably, an insertion hole for inserting a fastening component for fixing the stator core to the housing is provided outside the slit of the yoke portion.

Preferably, the slit has an arc shape.
Preferably, the slit has a corrugated shape.

  According to the present invention, it is possible to realize a quiet vehicle in which the vibration of the stator is reduced and the electromagnetic noise is reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a cross-sectional view of the rotary electric machine according to Embodiment 1 of the present invention when viewed from the axial direction.

FIG. 2 is a view of the stator core 2 of FIG. 1 as viewed from a direction perpendicular to the rotation axis.
Referring to FIGS. 1 and 2, motor 1 includes a stator core 2 and a rotor 4. The rotor 4 includes a rotor core formed by laminating electromagnetic steel plates, and keys 26 and 28 that mesh with a key groove of a shaft (not shown) are formed on the rotor core. In addition, eight sets of permanent magnets 22 and 24 are equally arranged on the rotor core.

  Stator core 2 includes 48 tooth portions 6 extending toward the rotation axis center of the rotor. A coil is wound around each tooth portion 6, and the coil is accommodated in a slot between the teeth.

  The stator core 2 further includes an annular yoke portion 7 located outside the 48 tooth portions 6 and connecting the 48 tooth portions 6. The yoke portion 7 is provided with three slits along the outer shape.

  Stator core 2 further includes fillers 8, 10, and 12 filled in three slits. This filler is an elastic body such as resin or rubber. Each slit has an arc shape, and has a central portion that is narrower than both end portions.

  Holes 14, 16, and 18 for inserting bolts, which are fastening parts for fixing the stator core 2 to a housing such as a bracket, are formed on the outer side when viewed from the rotation center of the fillers 8, 10, and 12 filled in the three slits. Is provided.

  Thus, by arranging the elastic body sealed in the slit on the inner peripheral side of each bolt hole, it is possible to prevent the vibration of the teeth from being transmitted from the bolt to the housing. This is because when the vibration of the teeth due to the electromagnetic force is transmitted from the teeth portion 6 to the outer periphery via the yoke portion 7, it is absorbed and attenuated by the fillers 8, 10, and 12 which are elastic bodies enclosed in the slits. is there. That is, the elastic body receives the vibration and deforms to generate heat and consume energy to attenuate the vibration. Heat is dissipated by air cooling or oil cooling.

  Moreover, by narrowing the width of the slit and widening both ends, the elastic body in the narrow center part absorbs high frequencies, and the elastic body absorbs low frequencies as it approaches both ends. In addition, you may deform | transform so that the width | variety of the center part of a slit may be wide and the width | variety of both ends may be narrowed.

  In other words, electromagnetic waves can be generated by changing the width in the slit radial direction according to the frequency band to be absorbed, such as absorbing high frequency in the narrow portion of the slit in the radial direction of the stator and absorbing low frequency in the wide portion. Reduce. For this reason, it is possible to reduce electromagnetic noise in a wide band.

  Further, a reduction in torque ripple can be expected also in the rotational direction. That is, the force applied to the teeth portion along the rotational direction exerts a shearing force on the fillers 8, 10, and 12, and this shearing force is converted into heat by the elasticity of the filler, resulting in attenuation.

  With such a configuration, the effect of damping can be increased without changing the physique and weight of the stator teeth compared with the conventional one.

  FIG. 3 is a flowchart for explaining the manufacturing process of the stator teeth of the present embodiment.

  Referring to FIG. 3, first, in step S1, the electromagnetic steel sheet is punched into a shape in which slits, bolt holes and teeth shown in FIG. 1 are formed.

  Subsequently, in step S2, a plurality of electromagnetic steel sheets are laminated together with the tooth positions, slit positions, and the like.

  Subsequently, the magnetic steel sheets laminated in step S3 are welded together to form a core integrated with the magnetic steel sheets.

  Further, in step S4, an integrated core is placed on a rubber sheet or the like and an elastic body is poured. In the case of a resin, the elastic body may be a resin that is cured by heat curing or aging. Moreover, you may perform the vulcanization adhesion which mixes and pours into rubber | gum. When the hardening of the elastic body is completed in step S5, the wire is wound through a slot on the side of the stator teeth in step S6. In step S7, the stator assembly is completed.

  As described above, in the first embodiment, since the slit having a shape along the outer shape of the stator core is provided and the filler for vibration damping is filled, for example, a viscoelastic body is inserted between the stator core and the housing. The ease of assembly for the method is improved.

  In addition, by changing the slit width according to the place without making it uniform, it is possible to exhibit vibration absorption characteristics in a wide frequency band.

  Furthermore, since the position of the slit is set inside the bolt hole position, it is possible to suppress vibration propagating from the bolt to the entire transaxle.

[Modification of Embodiment 1]
FIG. 4 is a diagram for explaining a modification of the first embodiment.

  As shown in FIG. 4, the slit shape may be corrugated instead of the filler 12 having a slit shape in an arc shape, and the filler 12A may be filled therewith. By making the slit shape corrugated, the “absolute amount”, “deformation amount”, and “heat dissipating area” of the filler increase, and the damping efficiency can be increased.

  In addition, by changing the hardness of the filler depending on the location, it is possible to absorb a frequency at which vibration easily occurs at each location due to factors other than the stator. For example, the hardness of the portion of the filler 12 in FIG. 1 may be made harder than that of the fillers 8 and 10, or conversely, the hardness may be softened. Thus, the resonance point may be eliminated by changing the hardness of the filler depending on the location.

  Further, the slits are arranged at unequal pitches, that is, the slits filled with the filler 12 are moved away from the slits of the filler 8 so as to be close to the slits of the filler 10, and the pitches of the three slits are made unequal pitches. It is also possible to eliminate the resonance point.

[Embodiment 2]
FIG. 5 is a diagram for explaining the shape of the stator core used in the second embodiment.

  Referring to FIG. 5, stator core 2 </ b> A includes elastic bodies 101 to 110 instead of fillers 8, 10, and 12 filled in the slit in the shape of stator core 2 shown in FIG. 1.

  That is, in the stator core 2A, a plurality of grooves having different lengths and widths are provided at unequal pitches from the outer periphery to the center of the stator core instead of providing slits along the outer periphery of the yoke portion, and resin, rubber, etc. are provided in the grooves. The elastic bodies 101 to 110 are enclosed.

  By doing so, when the stator core 2A is deformed by electromagnetic force, the vibrations are absorbed and attenuated by the elastic bodies 101 to 110 enclosed in the grooves. Since grooves having different lengths and widths are provided to enclose the elastic body, the absorption frequency at each location is different, so that vibrations in a wide band can be absorbed. Moreover, since the groove | channel which encloses the elastic bodies 101-110 is an unequal pitch, a resonance point can be excluded.

In addition, the same effects as those of the first embodiment can be obtained.
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is sectional drawing which looked at the rotary electric machine of Embodiment 1 of this invention from the axial direction. It is the figure which looked at the stator core 2 of FIG. 1 from the direction perpendicular | vertical to a rotating shaft. It is a flowchart for demonstrating the manufacturing process of the stator teeth of this Embodiment. FIG. 10 is a diagram for illustrating a modification of the first embodiment. FIG. 10 is a diagram for explaining a shape of a stator core used in the second embodiment. It is a figure for demonstrating the exciting force of a permanent magnet motor. It is the figure which showed the change of the exciting force with respect to the position of the stator teeth in time t1, t2, t3.

Explanation of symbols

  1 motor, 2A stator core, 4 rotor, 6 teeth, 7 yoke, 8, 10, 12, 12A filler, 14, 16, 18 holes, 22, 24 permanent magnet, 26, 28 keys, 101-110 Elastic body.

Claims (5)

A plurality of teeth extending toward the center of the rotation axis;
An annular yoke portion that is located outside the plurality of teeth portions and connects the plurality of teeth portions;
A stator core of a rotating electrical machine, comprising: a filler provided in a slit provided along the outer shape of the yoke portion in the yoke portion.   The stator core of the rotating electrical machine according to claim 1, wherein the slit has a first portion and a second portion that is narrower than the first portion.   The stator core for a rotating electrical machine according to claim 1 or 2, wherein an insertion hole for inserting a fastening component for fixing the stator core to a housing is provided outside the slit of the yoke portion.   The stator core of the rotating electrical machine according to claim 1, wherein the slit has an arc shape.   The stator core of the rotating electrical machine according to any one of claims 1 to 3, wherein the slit has a corrugated shape.

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