JP4490736B2 - Rotating electric machine - Google Patents

Description

  The present invention relates to a rotating electrical machine, and more particularly to a technique for suppressing vibration and noise.

  In recent years, due to remarkable progress in research and development of permanent magnets, permanent magnets with a high magnetic energy product have been developed, and it has become possible to reduce the size and increase the output of rotating electrical machines. However, especially in rotating electrical machines used in vehicles, a reduction in size and weight is required, so a robust structure with sufficient thickness of the frame and case placed outside the stator core can be achieved. Therefore, there is a problem that vibration and noise generated from the rotating electric machine cannot be sufficiently suppressed.

  Therefore, the conventional rotating electrical machine has a stator core that is framed by a shelf plate that is arranged in the circumferential direction on the inner peripheral surface of the frame and a rib that is arranged to extend in the axial direction on the outer periphery of the stator core. An elastic spring structure is formed by providing a notch in the axial direction at a position corresponding to the load point of the rib (the part that transmits the load of the stator core to the frame). The vibration of the stator core is attenuated, and the vibration and noise released to the outside of the rotating electrical machine are blocked (see, for example, Patent Document 1).

  In addition, as a general countermeasure against vibration and noise in rotating electrical machines, the stator core, stator frame, frame dimensions, support method, or mass is changed, and the natural frequency (frequency) of rotating electrical machines is outside the operating frequency range. Is often used to avoid resonance phenomenon (for example, see Patent Document 2).

  Here, the vibration / noise generation mechanism in the rotating electrical machine will be described with reference to FIGS. FIG. 10 is a cross-sectional view showing a conventional permanent magnet type reluctance type rotating electrical machine having a 4-pole rotor cut along a plane orthogonal to the rotation axis.

  In FIG. 10, a stator 102 has a stator core 103 and an armature winding 104, and a rotor 108 is provided inside thereof. The stator core 103 is configured by laminating electromagnetic steel plates, and a stator slot 105 that accommodates the armature winding 104 and a stator tooth 106 that faces the rotor 108 are formed on the inner peripheral side thereof. Has been. Further, the outer periphery of the stator 102 is supported and fixed to the stator frame 101 by shrink fitting or press fitting.

  The rotor 108 includes a rotor core 109 and a permanent magnet 111 embedded in the permanent magnet embedding hole 110, and a rotor shaft 112 at the center. An air cap 107 is formed between the stator teeth 106 formed on the stator 102 and the outer periphery of the rotor core 109 constituting the rotor 108. A pair of permanent magnets 111 embedded in the rotor core 109 is called a magnetic pole part 113, and a gap between two adjacent magnetic pole parts 113 is called a magnetic pole part 114.

  FIG. 11 is a diagram for explaining the distribution of electromagnetic force (magnetic attraction force) generated in the portion of the stator teeth 106 of the permanent magnet type reluctance type rotating electrical machine shown in FIG. 10 and the natural vibration mode of the stator core 109. It is.

10 and 11, when a current flows through the armature winding 104, a magnetic path passing through the stator core 103, the air gap 107, and the magnetic pole portion 113 of the rotor 108 is formed, and the stator teeth 106 and the rotor are formed. An electromagnetic force (magnetic attraction force) 115 attracting each other is generated between the magnetic pole portion 113 and the magnetic pole portion 108. Since the electromagnetic force 115 is generated in each magnetic pole portion, the electromagnetic force distribution 116 has four diameter nodes in the circumferential direction, and the stator core 103 vibrates via the stator teeth 106. In addition, when there is a natural vibration mode 117 of a four-diameter node similar to the electromagnetic force distribution 116 of the stator core 103 within the rotation speed range, and the natural frequency and the frequency of the electromagnetic force 115 coincide, the stator core 103 generates a resonance phenomenon and generates a large vibration and noise.
JP 2002-51503 A (FIGS. 9 to 12) JP 7-154950 A

  In the rotating electrical machine described in Patent Document 1 described above, there is a problem that the physique of the rotating electrical machine becomes large because it is necessary to arrange ribs and shelf boards outside the stator. Further, the technique disclosed in Patent Document 1 insulates the vibration propagating from the stator core to the frame, and cannot suppress the vibration itself of the stator core that is a vibration / noise source. Accordingly, there is a problem that the insulation life of the armature winding is shortened due to the vibration of the stator core, and the reliability of the rotating electrical machine is lowered.

  In addition, since a rotating electric machine used in a vehicle requires a wide range of variable speeds, an excitation frequency by an electromagnetic force serving as an excitation source is also wide. Therefore, as disclosed in Patent Document 2, measures are taken to change the natural frequency of the rotating electrical machine and to avoid the resonance phenomenon by changing the size, shape, support method, or mass of the components of the rotating electrical machine. However, since the range of the excitation frequency is wide with respect to the adjustment range of the natural frequency, there is always a resonance point where the natural frequency and the excitation frequency coincide with each other to cause a resonance phenomenon. Therefore, there is a problem that vibration and noise cannot be avoided in a rotating electric machine used in a wide variable speed range.

    The present invention has been made in order to solve the above-mentioned problems, and the problem is that rotation and vibration and noise can be reduced and reliability can be improved without degrading performance or increasing volume and weight. It is to provide an electric machine.

In order to solve the above-described problems, a rotating electrical machine according to the present invention is a rotating electrical machine including a stator including an annular stator core and a rotor that is disposed in a hollow portion of the stator core and rotates. The core includes a first stator core having a first slit formed radially on the outer peripheral side, and a second stator core having a second slit formed radially on the outer peripheral side, the stator core and the second stator core, circumferential position of the first slit so as to differ from the circumferential position of the second slit, are stacked alternately in the axial direction of the rotor, the first The first stator core further includes a third slit formed radially on the inner peripheral side of the first stator core, and the second stator core further includes an inner portion of the second stator core. A fourth slit formed in the radial direction on the circumferential side, and the first stator core and the front The second stator iron core is alternately stacked in the axial direction of the rotor such that the circumferential position of the third slit is different from the circumferential position of the fourth slit. The first slit formed in the stator core includes a plurality of slits formed at equal intervals in the circumferential direction, and the third slit formed in the first stator core includes a plurality of first slits. A plurality of slits formed between two adjacent slits in the slit, and the second slits formed in the second stator core are formed at positions at equal intervals in the circumferential direction. The fourth slit formed in the second stator iron core is composed of a plurality of slits formed in the middle of two adjacent slits in the plurality of second slits. It is characterized by.

According to the rotating electrical machine of the present invention, the stator core is configured by stacking the first stator core and the second stator core so that the circumferential positions of the first slit and the second slit are different. Therefore, frictional damping occurs between the first stator core and the second stator core, and vibration and noise of the entire stator core can be suppressed without incurring performance degradation or volume and weight increase. As a result, the reliability of the rotating electrical machine can be improved. In addition, by providing the circumferential positions of the third slit and the fourth slit in the central part of the first slit and the second slit, the first stator core and the first stator core having different circumferential positions where the slits are formed and A large deformation difference between the two stator cores can be obtained.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each of the following examples, a permanent magnet type reluctance type rotating electrical machine having an 8-pole rotor will be described as an example. However, the present invention is not limited to a rotating electrical machine using a permanent magnet, The number of child poles is not limited to eight.

  FIG. 1 is a cross-sectional view of a rotating electrical machine according to Embodiment 1 of the present invention cut by a plane orthogonal to the rotation axis, and FIG. 2 is a fixing used in the rotating electrical machine according to Embodiment 1 of the present invention. It is an external appearance perspective view which shows the external appearance after the assembly of a child iron core.

  In FIG. 1, a stator 1 has a stator core 2 and an armature winding 3, and a rotor 4 is provided on the inside thereof. The stator core 2 is configured by laminating annular magnetic steel plates, and a stator slot 5 for accommodating the armature winding 3 and a stator tooth 6 facing the rotor 4 on the inner peripheral side thereof. Is formed. Further, the outer periphery of the stator 1 is supported and fixed to a stator frame (not shown) by shrink fitting or press fitting.

  The rotor 4 is disposed in the hollow portion of the stator core 2 so as to have a predetermined air gap G between the rotor 4 and the stator teeth 6. The rotor 4 includes a rotor core 7 and a permanent magnet 9 embedded in the permanent magnet embedded hole 8, and includes a rotor shaft 10 in the center. The rotor core 7 is configured by laminating electromagnetic steel plates. In the rotor core 7, easy magnetization directions and difficult magnetization directions are alternately formed in the circumferential direction around the rotation axis.

  Further, in order to form magnetic irregularities on the outer peripheral surface of the rotor 4, a permanent magnet embedded hole 8 is formed along the easy magnetization direction, and the permanent magnet embedded hole 8 extends in the easy magnetization direction. A permanent magnet 9 is fitted along and fixed by an adhesive or the like. The rotor 4 rotates around the rotor shaft 10 by a rotating magnetic field generated by current flowing through the armature winding 3 applied to the stator core 2.

  The stator iron core 2 is a first stator iron core 2a having first slits 11a formed radially at four circumferentially spaced positions on the outer circumferential side thereof, and the first stator. A second stator core 2b having the same structure as the iron core 2a and having a second slit 11b at a position shifted by 45 degrees from the first slit 11a is laminated in the axial direction. Each of the first stator core 2a and the second stator core 2b is configured by stacking a plurality of electromagnetic steel plates.

  The first slit 11 a and the second slit 11 b are formed at positions corresponding to the stator teeth 6 on the outer peripheral side of the stator core 2. The first fixed teeth of the present invention correspond to the fixed teeth 6 provided on the first stator core 2a, and the second fixed teeth of the present invention correspond to the fixed teeth 6 provided on the second stator core 2b. To do. Furthermore, the slit width W of the first slit 11a and the second slit 11b is set to be equal to or smaller than the radial gap between the stator 1 and the rotor 4, that is, the air gap G.

  Next, the vibration characteristics of the rotating electrical machine according to the first embodiment of the present invention configured as described above will be described with reference to the diagram illustrating the vibration mode of the stator core of the rotating electrical machine illustrated in FIG. 3.

  The stator core 2 has vibration modes in a direction that is easily deformed and a direction that is difficult to be deformed by providing a slit as a natural vibration mode that represents the natural frequency. And the vibration mode 20 of the 1st stator core 2a provided with the 1st slit 11a and the vibration mode 21 of the 2nd stator core 2b provided with the 2nd slit 11b become a reverse phase (180 degree reversal). . Here, since the first stator core 2a and the second stator core 2b are configured to overlap in the axial direction, friction damping occurs between the first stator core 2a and the second stator core 2b. .

  Further, since the slits formed on the outer peripheral side of the stator core 2 are arranged at equal intervals, the vibration mode is regularly formed. Therefore, the vibration modes of the first stator core 2a and the second stator core 2b can be surely reversed in phase.

  Further, the first slit 11 a and the second slit 11 b are formed on the outer peripheral side of the stator core 2 and at positions corresponding to the stator teeth 6 having a lower magnetic flux density than positions corresponding to the stator slots 5. In addition, by making the slit width W of the first slit 11a and the second slit 11b equal to or less than the gap of the air gap G, there is little influence on the magnetic characteristics as the rotating electrical machine.

  As described above, according to the rotating electrical machine according to the first embodiment of the present invention, since the frictional damping is generated between the first stator core 2a and the second stator core 2b, the stator Vibration and noise of the entire iron core 2 can be suppressed. Further, since the vibration mode is formed regularly, it is possible to obtain the maximum damping effect. Further, since the slit is provided at a position where the magnetic density is low and the slit width W is equal to or less than the air gap G, it is possible to obtain a damping effect without impeding the performance of the rotating electrical machine.

  Next, a rotating electrical machine according to a second embodiment of the present invention will be described with reference to FIGS. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and redundant description is omitted.

  FIG. 4 is a cross-sectional view of the rotating electrical machine according to the second embodiment of the present invention cut by a plane orthogonal to the rotation axis, and FIG. 5 is a fixing used in the rotating electrical machine according to the second embodiment of the present invention. It is an external appearance perspective view which shows the external appearance after the assembly of a child iron core.

  In FIG. 4, the stator core 2 is a depth formed in the radial direction at four positions at equal intervals in the circumferential direction on the outer circumferential side (refers to the length in the radial direction. ) A first stator core 2a having an X first slit 11a and a second stator having a second slit 11b having a depth Y at a position shifted by 45 degrees from the first slit 11a of the first stator core 2a. The iron core 2b is laminated in the axial direction. The depth Y of the second slit 11b is formed to be shorter than the depth of the first slit 11a.

  FIG. 5 shows a first slit 11a having a slit Y without a slit and a first slit 11a with a depth X, in which the depth Y of the second slit 11b is extremely shortened, in other words, the depth Y is zero. 1 shows a stator 1 configured by laminating one stator core 2a in the axial direction.

  Next, vibration characteristics of the rotating electrical machine according to the second embodiment of the present invention configured as described above will be described.

  The natural frequency of the first stator core 2a is low because the depth X of the first slit 11a is deep, and the natural frequency of the second stator core 2b is high because the depth Y of the second slit 11b is shallow. Become. By configuring the stator 1 by stacking the first stator core 2a and the second stator core 2b (or the second stator core 2b ′) having different natural frequencies (frequency) in the axial direction, each stator Since the frequency of the iron core responding to the electromagnetic excitation force is different, the deformation amount of the stator core 2 at the same frequency (number of revolutions) is relatively different in a wide frequency range (number of revolutions).

  The mechanical rigidity of the annular first stator core 2a having the deep first slit 11a is that of the second stator core 2b having the shallow second slit 11b or the second stator core 2b 'having no slit. Reduced compared to mechanical rigidity. In the rotating electrical machine according to the second embodiment, the first stator core 2a having a low mechanical rigidity and the second stator core 2b or the second stator core 2b ′ having a high mechanical rigidity are stacked in the axial direction. 1 is configured, the mechanical rigidity of the stator 1 as a whole can be increased as compared with the stator 1 configured by stacking only the first stator cores 2a having small mechanical rigidity.

  As described above, according to the rotating electrical machine according to the second embodiment of the present invention, the first stator core 2a and the second stator core 2b or the second stator core 2b ′ having different natural frequencies are connected to the shaft. By configuring the stator 1 in combination with the direction, the damping action between the first stator core 2a and the second stator core 2b or the second stator core 2b 'can be achieved in a wide frequency range (rotational speed range). Obtainable. As a result, vibration and noise of the stator core 2 can be suppressed.

  In addition, by configuring the stator 1 by combining the first stator core 2a and the second stator core 2b or the second stator core 2b ′ having different mechanical rigidity in the axial direction, the stator core 2 The rigidity as a whole can be increased. As a result, it is possible to obtain an effect of suppressing vibration and noise due to high rigidity.

  Next, a rotary electric machine according to Embodiment 3 of the present invention will be described with reference to FIGS. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and redundant description is omitted.

  FIG. 6 is a cross-sectional view of the rotating electrical machine according to the third embodiment of the present invention cut by a plane including the rotating shaft, and FIG. 7 is a damping material used in the rotating electrical machine according to the third embodiment of the present invention. It is an external appearance perspective view which shows the external appearance of a sheet | seat. In addition, the armature winding 3 in FIG. 6 has shown the coil end part.

  In FIG. 6, the stator core 2 is configured such that an attenuation material sheet 12 as an attenuation material is sandwiched between a first stator core 2 a and a second stator core 2 b that are combined in an axial direction. As shown in FIG. 7, the damping material sheet 12 has the same shape as each electromagnetic steel plate constituting the stator core 2, and is made of, for example, a rubber material having high damping characteristics. Instead of the damping material sheet 12 interposed between the first stator core 2a and the second stator core 2b, damping characteristics are provided on at least one surface of the first stator core 2a and the second stator core 2b. High damping liquids or particles can be applied to make the damping material.

  Next, vibration characteristics of the rotating electrical machine according to the third embodiment of the present invention configured as described above will be described.

  A second stator core 2a having a first stator core 2a having a first slit 11a and a second stator core 2b having a second slit 11b at a position shifted by 45 degrees from the first slit 11a of the first stator core 2a. Due to the deformation difference of the stator core 2b, a large damping action occurs in the portion of the damping material sheet 12.

  As described above, according to the rotating electrical machine according to the third embodiment of the present invention, the damping material sheet 12 is interposed between the first stator core 2a and the second stator core 2b. Compared to the stator core 2 in which 12 is not interposed, the damping effect of the damping material sheet 12 can sufficiently achieve the effects of vibration and noise suppression. Furthermore, since the damping material sheet 12 is in the form of a sheet, the handling becomes easy, and the time and labor required for molding and assembly can be reduced, so that the productivity is improved. In addition, when the particles having high damping characteristics are coated on the surface of the first stator core 2a or the second stator core 2b, the thickness of the portion where the damping material sheet 12 is sandwiched can be reduced. The direction dimension can be shortened, and the rotating electrical machine can be downsized.

  Next, a rotary electric machine according to Embodiment 4 of the present invention will be described with reference to FIGS. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and redundant description is omitted.

  FIG. 8 is a cross-sectional view showing a rotary electric machine according to Embodiment 4 of the present invention cut along a plane orthogonal to the rotation axis, and FIG. 9 is an enlarged cross-sectional view showing a part of FIG. .

  The stator core 2 is provided on the inner peripheral side of the stator core 2 so as to sandwich the center position in the circumferential direction between two adjacent first slits 11a in the first stator core 2a according to the first embodiment. The two stator slots 5 adjacent to the third stator core in which the third slits 11c are formed at the bottoms of the two stator slots 5 formed, and the second stator core 2b according to the first embodiment. A fourth stator core in which fourth slits 11d are formed at the bottoms of two stator slots 5 provided on the inner peripheral side of the stator core 2 so as to sandwich the circumferential center position of 11b. It is configured to be laminated in the axial direction.

  Further, as shown in an enlarged view in FIG. 9, a circular gap 13 larger than the slit width is formed at each end of the first slit 11a, the second slit 11b, the third slit 11c, and the fourth slit 11d. Has been.

  Next, vibration characteristics of the rotating electrical machine according to the fourth embodiment of the present invention configured as described above will be described. The slits were formed by providing the circumferential positions of the inner peripheral slits (the third slit 11c and the fourth slit 11d) at the center of the outer peripheral slit (the first slit 11a and the second slit 11b). A large difference in deformation between the third stator core and the fourth stator core having different circumferential positions can be obtained. At the same time, it is possible to regularly form amplitudes in a direction that easily vibrates and in a direction that hardly vibrates in the circumferential direction, and the phase of the vibration mode can be reliably reversed (shifted 180 degrees). Furthermore, a circular gap 13 is provided at the end of the slit, and the stress concentration generated at the end of the slit is alleviated by the deformation of the stator core 2.

  As described above, according to the rotating electric machine according to the fourth embodiment of the present invention, the third stator core and the fourth stator having different circumferential positions where the slits are formed are provided by providing the inner peripheral side slits. A large deformation difference from the iron core can be obtained, and the maximum damping effect can be obtained. As a result, the vibration and noise of the stator 1 can be further reduced. In addition, since the stress concentration is alleviated by the gaps 13 formed at the ends of the slits, the occurrence of cracks and breakage can be avoided, and the reliability of the rotating electrical machine is improved.

  In addition, this invention is not limited to the Example mentioned above. In the rotating electrical machine according to Example 4 described above, the first stator core 2a is provided with the first slit 11a and the third slit 11c, and the second stator core 2b is provided with the second slit 11b and the fourth slit 11d. However, it is also possible to provide only the third slit 11c in the first stator core 2a and provide only the fourth slit 11d in the second stator core 2b.

It is sectional drawing which cut | disconnects and shows the rotary electric machine which concerns on Example 1 of this invention by the surface orthogonal to a rotating shaft. It is an external appearance perspective view which shows the external appearance after the assembly of the stator core used with the rotary electric machine which concerns on Example 1 of this invention. It is a figure which shows the vibration mode of the stator core of the rotary electric machine which concerns on Example 1 of this invention. It is sectional drawing which cut | disconnects and shows the rotary electric machine which concerns on Example 2 of this invention by the surface orthogonal to a rotating shaft. It is an external appearance perspective view which shows the external appearance after the assembly of the stator core used with the rotary electric machine which concerns on Example 2 of this invention. It is sectional drawing which cut | disconnects and shows the rotary electric machine which concerns on Example 3 of this invention by the surface containing a rotating shaft. It is an external appearance perspective view which shows the external appearance of the attenuation material sheet used with the rotary electric machine which concerns on Example 3 of this invention. It is sectional drawing which cut | disconnects and shows the rotary electric machine which concerns on Example 4 of this invention by the surface orthogonal to a rotating shaft. It is an expanded sectional view which expands and shows a part of FIG. It is sectional drawing which cut | disconnects and shows the conventional permanent-magnet-type reluctance type rotary electric machine provided with the rotor of 4 poles in the surface orthogonal to a rotating shaft. It is a figure for demonstrating distribution of the electromagnetic force which generate | occur | produces in the rotary electric machine shown in FIG. 10, and the natural vibration mode of a stator core.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stator 2 Stator core 2a 1st stator core 2b 2nd stator core 2b '2nd stator core without a slit 3 Armature winding 4 Rotor 5 Stator slot 6 Stator teeth 7 Rotor core 8 Permanent Magnet embedded hole 9 Permanent magnet 10 Rotor shaft 11a First slit 11b Second slit 11c Third slit 11d Fourth slit 12 Damping material sheet 13 Air gap 20 First stator core vibration mode 21 Second stator core vibration Mode W Slit width G Air gap width X First slit depth Y Second slit depth

Claims (10)

In a rotating electrical machine comprising a stator including an annular stator core and a rotor arranged and rotated in a hollow portion of the stator core,
The stator core is
A first stator core having a first slit formed radially on the outer peripheral side;
A second stator core having a second slit formed radially on the outer peripheral side,
The first stator core and the second stator core are arranged in the axial direction of the rotor such that a circumferential position of the first slit is different from a circumferential position of the second slit. Alternately stacked ,
The first stator core further has a third slit formed radially on the inner peripheral side of the first stator core;
The second stator core further includes a fourth slit formed radially on the inner peripheral side of the second stator core,
The first stator core and the second stator core are arranged in the axial direction of the rotor such that the circumferential position of the third slit is different from the circumferential position of the fourth slit. Alternately stacked,
The first slit formed in the first stator core consists of a plurality of slits formed at positions that are equally spaced in the circumferential direction,
The third slit formed in the first stator core consists of a plurality of slits formed in the middle of two adjacent slits in the plurality of first slits,
The second slit formed in the second stator core consists of the same number of slits as the first slit formed at equal intervals in the circumferential direction,
The rotating electrical machine, wherein the fourth slit formed in the second stator iron core includes a plurality of slits formed between two adjacent slits in the plurality of second slits . Before Symbol The first stator core and the second stator core, as each of the plurality of first slits is positioned between the two second slits adjacent of the plurality of second slits The rotating electrical machine according to claim 1, wherein the rotating electrical machines are alternately stacked in an axial direction of the rotor. The first stator iron core includes a first stator tooth protruding toward an inner peripheral side of the first stator iron core, and the first slit is formed at a position corresponding to the first stator tooth. ,
The second stator core includes a second stator tooth protruding toward the inner peripheral side of the second stator core, and the second slit is formed at a position corresponding to the second stator tooth. The rotating electrical machine according to claim 1 or 2, characterized in that   The slit width of the first slit and the second slit is equal to or less than an air gap formed between the stator core and the rotor. The rotating electric machine according to the item.   5. The rotating electrical machine according to claim 1, wherein a length in a radial direction of the first slit is different from a length in a radial direction of the second slit.   6. The rotating electrical machine according to claim 5, wherein a length of the second slit in the radial direction is zero.   The rotating electrical machine according to any one of claims 1 to 6, wherein an attenuation material is sandwiched between the first slit and the second slit.   The rotating electrical machine according to claim 7, wherein the damping material is a damping material sheet formed in a sheet shape.   8. The rotating electrical machine according to claim 7, wherein the damping material is a liquid or particle having a high damping characteristic applied to at least one of the first stator core and the second stator core. . The rotating electrical machine according to claim 1, wherein a circular gap larger than a slit width of each slit is provided at end portions of the first slit, the second slit, the third slit, and the fourth slit.

Images