JP5446482B2 - Stator for adder motor - Google Patents

Description

  The present invention relates to an iron core of an electric motor, and more particularly to an adder-type electric motor stator manufactured by laminating and integrating a plurality of punched steel sheets.

  In recent years, there has been a strong demand for improving the efficiency and reducing the cost of various electric motors from the viewpoint of energy saving. On the other hand, electric motors used in refrigerators, washing machines, air conditioners, and the like have very high needs for low vibration and low noise in addition to high efficiency and low cost. In general, a stator for an electric motor is formed by punching steel sheets, laminating a predetermined number of sheets, and fastening them by bolting, caulking, or welding. The stator inserts a tooth portion, a yoke portion, and a winding coil. It is an integral structure composed of a slot portion that is a gap portion for the purpose, and is finally assembled as a part of an electric motor through a winding coil assembling process.

  As a method of fixing the stator to the case of the electric motor, the stator is fixed to a case having an inner diameter substantially the same as the outer diameter of the stator by shrink fitting or bolting. When the stator is incorporated into the electric motor, a winding coil is wound around the tooth portion, and a rotor in which a permanent magnet is embedded is attached inside the stator. An alternating current is passed through the winding coil, a rotating magnetic field is generated between the stator and the rotor, and the electric motor rotates.

  When the electric motor is operated, suction and repulsion are repeated between the permanent magnet of the rotor and the tip of the stator teeth, and electromagnetic excitation force is generated. The electromagnetic excitation force generated with the rotating magnetic field tends to cause the stator to vibrate, and in particular, tends to increase the force (radial force) that tends to deform in the radial direction. The radial force is concentrated on the tip of the tooth portion, the force propagates through the yoke portion, and the case portion is vibrated to vibrate the entire motor.

  In general, in order to make a structure in which the electromagnetically excited teeth portion vibration is difficult to propagate directly to the case, a method of reducing the vibration of the electric motor by providing a groove-shaped notch on the outer periphery of the stator is taken. The notch is usually positioned in a region including the outer peripheral side of the yoke located on the outer peripheral side of the teeth so as not to disturb the flow of magnetic flux generated in the stator as much as possible when the motor is operated.

  When the notches as described above are used, vibrations are difficult to propagate, but there is a problem that the rigidity around the stator where the notches exist is locally reduced. In addition, if the notch size is too large, the radial width of the yoke portion becomes small, and it becomes difficult for the magnetic flux to flow.

  Further, as shown in FIG. 1, the inversion motor having 6 magnetic poles rotates while maintaining the spatial mode of the electromagnetic excitation force 71 having a substantially equilateral triangle shape. When three center points of teeth with notches are selected, if the three center points are rotationally symmetrical in the circumferential direction of the yoke part, that is, are located in a substantially equilateral triangle shape, the outer periphery of the tooth part Since the notched region where the rigidity of the yoke portion located on the side is locally reduced is vibrated simultaneously, there is a problem that the vibration of the stator increases.

  Therefore, the number and area of notches existing on the outer periphery of the stator are minimized, and an efficient vibration reduction measure is required.

  Patent Document 1 discloses a stator for an inversion motor having 24 slots in which notches are arranged equally on the outer periphery of the yoke portion, and Patent Document 2 discloses a notch on the outer periphery of the yoke portion. Discloses a stator for an inversion motor having six magnetic poles and nine slots. Patent Document 3 discloses a single-phase two-pole having five or more substantially linear cutouts on the outer periphery of the yoke portion, and a quadrangle formed by straight lines including four cutouts. An electric motor having 24 slots is disclosed. The stators disclosed in these documents include a configuration in which, when three center points of teeth having notches are selected, the three center points are rotationally symmetrical in the circumferential direction of the yoke portion. .

JP 2004-297936 A JP 2008-278673 A JP 2006-238507 A

  In view of the above problems, the present invention has an object to provide a stator for an electric motor that suppresses vibration of the steel plate of the stator that occurs during operation of the motor and reduces the vibration level without substantially reducing the efficiency of the electric motor. And

In order to solve this problem, the gist of the present invention is as follows.
(1) In a stator in which a steel plate is punched into a predetermined shape, a plurality of one steel plate in which teeth and yoke portions are integrated, and the number of magnetic poles is 6 and the number of slots is 9
Of the teeth portions, 3 to 6 teeth portions have a groove-shaped notch only in a region including the outer periphery side of the yoke portion located on the outer periphery side of the 3 to 6 teeth portions. ,
Center point in how be selected three teeth, from the center of the stator on the center axis of the front hexene constant been teeth equidistant from the tooth portion having a notch of the groove The stator for an adder motor is characterized in that the three points are not rotationally symmetric with respect to the center of the stator.
(2) The stator for an addendum motor according to (1), wherein the notch is not in a state of being unevenly distributed in a semicircle of the yoke portion circumference. It should be noted that, when there are n notches, it is not in a state of being unevenly distributed in the semicircle, and even if n-1 are unevenly distributed in the semicircle, at least one notch is in the semicircle. A state that does not exist inside.
(3) The cross-sectional shape of the notch is a triangle, the depth of the notch is 0.3 to 0.5 times the thickness of the yoke portion, and the length is 0.8 to 1.4 times the width of the teeth portion. (1) or (2), the stator for an inversion motor.

  According to the present invention, it is possible to suppress the vibration of the steel plate of the stator that is generated when the electric motor is operated, and to reduce the vibration level of the electric motor without substantially reducing the efficiency of the electric motor.

It is a figure which shows the spatial mode of electromagnetic excitation force. It is a figure which shows the form of the stator for adduction type electric motors. It is a figure which shows the shape of the stator for internal motors. It is a figure which shows the frequency characteristic of the stators A and B. FIG. It is a figure which shows the natural vibration mode of the stators A and B. FIG. It is a figure which shows the outline | summary of a magnetic flux flow. It is a figure which shows the example of a notch cross-sectional shape. It is a figure which shows the example of creation of the stator for adder type electric motors. (A) It is a figure which shows the creation example of the stator which has four notches. (B) It is a figure which shows the creation example of the stator which has five notches. (C) It is a figure which shows the example of preparation of the stator which has six notches. (A) It is a figure which shows the example of preparation of a notch shape. (B) It is a figure which shows the example of preparation of a notch shape.

  Hereinafter, the present invention will be specifically described with reference to the drawings.

  FIG. 2 is a cross-sectional view of an inversion motor having 6 magnetic poles and 9 slots used for an air conditioner and a compressor of a refrigerator, which is a premise of the present invention. As shown in FIG. 2, the internal rotation type motor includes a stator 11 and a rotor 12, and the stator 11 includes an annular yoke portion 13, nine tooth portions 15 extending radially inward from the inner periphery 14 of the yoke portion, and a winding. The slot portion 17 is a gap portion for inserting the wire coil 22. The stator 11 is fixed to a case 21 having an inner diameter substantially the same as the outer diameter of the stator by shrink fitting or bolting (not shown). The stator 11 is a concentrated winding stator in which the winding coil 22 is wound directly around the tooth portion 15 before the stator 11 is incorporated into the adder motor. Inside the stator, a rotor 12 in which six permanent magnets 23 are embedded is attached so as to be rotatable about an axis.

  An alternating current is passed through the winding coil 22, a magnetic field is generated between the stator 11 and the rotor 12, and the electric motor rotates. When the electric motor is operated, attraction and repulsion are repeated between the permanent magnet 23 of the rotor 12 and the tooth tip 16 of the stator 11, and an electromagnetic excitation force 71 is generated. A groove-shaped notch 31 is provided on the outer periphery of the stator so that the electromagnetic excitation force 71 does not easily propagate directly to the case 21. The notch 31 is positioned in a region including the outer peripheral side of the yoke portion 13 positioned on the outer peripheral side of the tooth portion 15 so as not to disturb the flow of magnetic flux generated in the stator as much as possible when the electric motor is operated.

  The internal rotation type motor having 6 magnetic poles rotates while maintaining a spatial mode of electromagnetic excitation force having a substantially equilateral triangle shape as shown in FIG. When three center points of the tooth portion 15 where the notch 31 is present are selected, the three center points are located symmetrically in the circumferential direction of the yoke portion, that is, in a triangular shape, the outer periphery of the tooth portion Since the notched region where the rigidity of the yoke portion located on the side is locally reduced is vibrated simultaneously, the vibration of the stator increases.

  From this, the present inventors analytically investigated the relationship between the vibration characteristics and the notch arrangement of the stator for an inversion motor with 6 magnetic poles shown in FIG. 2 using the finite element method. .

  FIG. 3 shows an example of the stator shape used for the analysis. The stator shown in FIG. 3 (a) has three notches 31 in a region including the outer peripheral side 18 of the yoke portion located on the outer peripheral side of the tooth portion 15, and is disposed at a rotationally symmetric position in the circumferential direction. Has been. On the other hand, the stator of FIG. 3B has three notches 31 in the region including the outer peripheral side 18 of the yoke portion located on the outer peripheral side of the tooth portion 15 as in the stator of FIG. However, it is arranged at a non-rotationally symmetric position in the circumferential direction.

  As described above, the internal-rotation motor having 6 magnetic poles rotates while maintaining the spatial mode of the electromagnetic excitation force having a substantially equilateral triangle shape as described above. The dynamic load 41 was applied in three directions of the tooth tip portion 16 at various positions, and the frequency response analysis of the stator was performed. In the stator of FIG. 3 (a), when a dynamic load in three directions is simultaneously applied to the tooth tip 16 where the three notches 31 are located, vibration increases, and the stator of FIG. 3 (b). Then, when the dynamic load in two directions among the dynamic loads in the three directions is applied to the tooth tip 16 where the two notches 31 are located, the vibration becomes large.

  FIG. 4 is a representative example of frequency response characteristics in each stator shown in FIG. The response characteristics are those at the response evaluation point 42 shown in FIG. 3, and the acceleration per unit dynamic load is evaluated as a vibration value.

  FIG. 5 shows the natural vibration modes of the respective stators shown in FIG. 3 obtained by the eigenmode analysis by the finite element method. Each stator has a triangular natural vibration mode shown in FIG. 5, and each peak frequency existing in the vicinity of 4 kHz in the frequency response characteristic of FIG. 4 has a primary natural frequency in the triangular natural mode. Equivalent to.

  As shown in FIGS. 4 and 5, the stator shown in FIG. 3B has a vibration value of 3 to 4 dB smaller at the time of peak vibration than the stator shown in FIG. Therefore, it can be seen that it is effective to reduce vibration during operation of the motor if the notches 31 are not positioned rotationally symmetrically in the circumferential direction in the region including the outer peripheral side 18 of the yoke portion located on the outer peripheral side of the teeth portion 15. . If the number of the notches 31 is two or less, the electromagnetic excitation force 71 easily propagates directly to the case 21 through the stator 11, and at least three are necessary. In the case of a stator with 9 slots (9 teeth), if the number is 7 or more, select the three center points of the teeth part where the notch 31 exists, and how to select those three points. Even if it is not possible to take an arrangement that is not rotationally symmetrical in the circumferential direction, six or less is desirable.

  Furthermore, when the rotational balance of the electric motor is taken into account, the notches 31 are arranged in the circumferential direction so as to prevent uneven deformation of the stator when the electromagnetic excitation force is applied. Therefore, the notch may be arranged not to be biased particularly in the semicircle of the yoke circumference to prevent deformation in addition to vibration reduction.

  On the other hand, when a stator having 6 magnetic poles and 9 slots is incorporated in an internal motor, an alternating current is applied to the winding coil, and the motor operates, as shown in FIG. The magnetic flux 52 of the yoke portion that connects the magnetic flux 51 that flows in the radial direction through the portion 15 tends to concentrate in the area 53 indicated by the hatched portion. The region 53 where the magnetic flux concentrates is in the range of about 0.5 times the thickness Y of the yoke portion in the radial direction. Therefore, in order not to deteriorate the iron loss of the electric motor, the notch 31 is preferably present at a position that does not disturb the magnetic flux flow of the magnetic fluxes 51 and 52.

  However, it is preferable that the notch has a triangular cross-sectional shape and is provided in a region including the outer peripheral side 18 of the yoke portion located on the outer peripheral side of the tooth portion 15, and the notch depth D is 0.5 times the thickness Y of the yoke portion. Hereinafter, the notch length W is preferably 1.4 times or less the width T of the tooth portion.

  On the other hand, when the size of the notch 31 becomes extremely small, the electromagnetic excitation force easily propagates directly to the case 21, the notch depth D is 0.3 times or more the yoke thickness Y, and the notch length W is 0.8 times or more of the width T of the teeth portion is preferable. Further, the shape of the notch 31 may be a triangular cross-sectional shape that is asymmetric with respect to the teeth center axis 19, as shown in FIG.

  From the above, in the stator having 6 magnetic poles and 9 slots, the notch 31 is rotationally symmetric in the circumferential direction in the region including the outer peripheral side 18 of the yoke located on the outer peripheral side of the tooth portion 15. It can be said that it is effective for the vibration reduction at the time of an electric motor operation to be not located in.

  FIG. 8 shows the stator for an inversion motor in the first embodiment of the present invention. The radius Rt of the tip of the tooth portion 15 is 30 mm, the radius of the inner periphery Ri of the yoke portion 13 is 45 mm, the radius Ro of the end surface 18 of the outer peripheral side 18 of the yoke portion 13 is Ro = 55 mm, and the width T of the tooth portion 15 is 12 mm. The thickness Y of 13 is 10 mm, the number of the slot portions 17 is 9, and the number of magnetic poles is 6. One steel sheet to be laminated has a thickness of 0.35 mm and a lamination height of 40 mm, and the laminated steel sheet is fixed by a welded portion (not shown) on the outer peripheral side of each tooth portion 15. The stator 11 is fixed to a case 21 of the electric motor by bolting (not shown).

  Three groove-shaped notches 31 are arranged in a region including the outer peripheral side 18 of the yoke part 13 located on the outer peripheral side of the tooth part 15, and the depth D of the notch 31 is 4 mm. The thickness Y is 0.4 times, the width W of the notch 31 is 16 mm, and is about 1.3 times the width T of the tooth portion 15. The mutual positional relationship of the notches 31 is non-rotationally symmetric in the circumferential direction, and teeth that do not have the notches 31 are arranged in a non-rotationally symmetrical manner in the circumferential direction.

  As a comparative example, in the shape of the stator shown in FIG. 3 (a), three groove-shaped notches 31 are arranged in the circumferential direction including the outer peripheral side 18 of the yoke portion located on the outer peripheral side of the tooth portion 15. The stator 11 arranged symmetrically was created.

  In the test, an electric motor equipped with each stator was operated under the conditions of a rotational speed of 3000 [rpm] and a torque of 3 [Nm], an accelerometer was attached to the outer periphery of the case, and the vibration acceleration of the case was measured. The vibration acceleration level was measured up to a frequency range up to 10 kHz, and evaluated with an overall value [dB]. As a result of detailed analysis of vibration acceleration data after measurement, the vibration acceleration level of the motor equipped with the stator of the present invention example shown in FIG. 8 is the motor equipped with the stator shown in FIG. 3A as a comparative example. It was confirmed that it was 3-4 dB below the vibration acceleration level.

  Moreover, as shown in FIG. 8, each notch 31 is located on the outer peripheral side 18 of the yoke part 13 located on the outer peripheral side of the tooth part 15 that does not disturb the magnetic flux, and hardly reduces the efficiency of the motor. It was.

  FIG. 9 shows a stator for an inversion motor according to a second embodiment of the present invention. Components having the same shape as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  FIG. 9A is an example of creating a stator having four notches, and FIG. 9B is an example of creating a stator having five notches. c) is an example of making a stator having six notches. As in the first embodiment, the notches 31 are distributed and arranged so as not to be unevenly distributed in the semicircle of the circumference of the yoke portion 13. By disposing the notches 31 in a distributed manner, when an electromagnetic excitation force is applied, the stator can be prevented from being deformed unevenly, and the structure is stable in terms of rotation balance.

  FIG. 10 shows a stator for an inversion motor according to a third embodiment of the present invention. Components having the same shape as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted. FIG. 10A shows three notches having a triangular cross-sectional shape arranged in a non-rotationally symmetric manner in the circumferential direction as in the first embodiment, and the depth D of the notches is 0. It is set to 3.0 mm, which is 3 times. Further, the width W of the notch is 9.6 mm so as to be 0.8 times the width of the tooth portion in the circumferential direction from the central axis of the tooth portion. On the other hand, FIG. 10B shows a notch having a triangular cross-sectional shape in which three notches are arranged in a non-rotationally symmetrical manner in the circumferential direction in the same manner as in the first embodiment. The thickness is 5.0 mm, which is 0.5 times the thickness. The width W of the notch is set to 16.8 mm so as to be 1.4 times the width of the tooth portion in the circumferential direction from the center axis of the tooth. These stators have the effect of reducing vibrations by maintaining the predetermined motor performance without obstructing the flow of magnetic flux, and reducing the phenomenon of electromagnetic excitation force propagating to the motor case. It has a structure.

DESCRIPTION OF SYMBOLS 11 Stator 12 Rotor 13 Yoke part 14 Yoke part inner periphery 15 Tees part 16 Teeth tip part 17 Slot part 18 Outer side of yoke part 19 Teeth center axis 21 Case 22 Winding coil 23 Permanent magnet 31 Notch 41 Dynamic load 42 Response evaluation point 51 Magnetic flux flowing in the radial direction 52 Magnetic flux of the yoke part 53 Area where the magnetic flux concentrates 71 Electromagnetic excitation force

Claims (3)

In a stator in which a steel plate is punched into a predetermined shape, a plurality of one steel plate in which teeth and yoke portions are integrated, and the number of magnetic poles is six and the number of slots is nine.
Of the teeth portions, 3 to 6 teeth portions have a groove-shaped notch only in a region including the outer periphery side of the yoke portion located on the outer periphery side of the 3 to 6 teeth portions. ,
Center point in how be selected three teeth, from the center of the stator on the center axis of the front hexene constant been teeth equidistant from the tooth portion having a notch of the groove The stator for an adder motor is characterized in that the three points are not rotationally symmetric with respect to the center of the stator.   2. The stator for an internal motor according to claim 1, wherein the notch is not in a state of being unevenly distributed within a semicircle of the yoke portion circumference.   The cross-sectional shape of the notch is a triangle, the depth of the notch is 0.3 to 0.5 times the thickness of the yoke portion, and the length is 0.8 to 1.4 times the width of the teeth portion. 3. The stator for an addendum electric motor according to claim 1, wherein the stator is for an adder type electric motor.

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