JP2005245131A - Method of designing stator, motor, coolant compressor, cooling device, and motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To put an electromagnetic force that acts between a tooth portion and a rotor into a desired function form. <P>SOLUTION: Distances (θ, ψ) between the tooth portion 10 and the rotor 2 are obtained (Step S1). Using electromagnetic simulation, electromagnetic forces Fn(θ, ψ) that act in the direction of a normal of an inside surface 100 are calculated (Step S2). A maximum value M(θ) of the electromagnetic forces Fn(θ, ψ) is acquired with regard to the rotational position ψ of the rotor 2 (Step S3). Using a desired function form G(θ), the distance between the inside surface of the tooth portion and the outside circumferential surface of the rotor is calculated (Step S4). Specifically, new distances L'(θ, ψ) are acquired by multiplying the distances (θ, ψ) by the square root of a value obtained by dividing the maximum value M(θ) by the desired function G(θ) with regard to the maximum value. The maximum value M(θ) of the electromagnetic force is calculated again (Step S5). Then, it is judged whether or not the difference between the maximum value M(θ) and the desired function G(θ) is within a permissible range (Step S6). Unless it is within the permissible range, the Steps S2 to S6 are performed repeatedly. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to motor design.

  The electromagnetic attraction force acting between the rotor and stator of the motor has a normal component that is an order of magnitude greater than the tangential component. The electromagnetic attracting force of the normal component is a main factor of motor vibration and noise.

  In order to reduce such vibration and noise, the shape of the rotor and stator has been devised. Such a device can be found, for example, in the following literature.

JP 2002-252956 A JP 2002-325410 A JP 2002-315243 A Japanese Patent No. 3301981 Japanese Unexamined Patent Publication No. 7-308057

  However, no clear method has yet been proposed to reduce even harmonics of the electrical angular frequency of the electromagnetic attractive force, and therefore the motor shape, for example, the optimal shape of the teeth, has also been clearly proposed. Not.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a design technique for making an electromagnetic force acting between a tooth portion and a rotor a desired function form, and to propose an optimum shape of a motor.

  A first aspect of the stator (1) according to the present invention includes an annular yoke (12) provided around a central axis and a plurality of teeth provided on the central axis side of the annular yoke and spaced apart from each other. Part (10). The tooth portion is provided on the side of the central axis of the root portion (10R) projecting from the yoke to the central axis, and when the central axis is taken in the axial direction (z), the tooth portion is positive. It has the 1st collar part (10P) which protrudes from the said root part on the angle direction (+ psi) side, and the 2nd collar part (10Q) which protrudes from the said root part on the negative angle direction (-psi) side. The distance from the central axis of the inner surface (101; 102; 103) facing the central axis of the tooth part is (i) the first position (10A) in the second collar part, the root part and the second part. An equal first distance is taken at the second position (10B) between the boundary (10W) with the heel part and the center (10N) of the root part, and (ii) on the negative direction side from the first position. Takes a second distance larger than the first distance, and (iii) takes a third distance smaller than the first distance between the first position and the second position.

  A second aspect of the stator (1) according to the present invention is the stator according to the first aspect, wherein the distance of the inner surface (103) from the central axis is (iv) the second position ( 10B), the first distance is taken on the positive angle direction (+ ψ) side.

  A third aspect of the stator (1) according to the present invention is the stator according to the first aspect or the second aspect, wherein the difference between the maximum value of the second distance and the first distance is: It is larger than the difference between the minimum value of the third distance and the first distance.

  A fourth aspect of the stator (1) according to the present invention is the stator according to the first aspect, in which the distance from the central axis of the inner surface (101; 102) is (iv) the second A fourth distance smaller than the first distance is taken between the position (10B) and the center (10N) of the root portion (10R).

  A fifth aspect of the stator (1) according to the present invention is the stator according to the fourth aspect, wherein the distance from the central axis of the inner surface (101) is (v) the root (10R). A fifth distance smaller than the first distance between the center (10N) and the third position (10C) of the first collar, and (vi) the positive direction relative to the third position On the (+ ψ) side, a sixth distance greater than the first distance is taken.

  A sixth aspect of the stator (1) according to the present invention is the stator according to the fourth aspect, wherein the difference between the maximum value of the second distance and the first distance is the third distance. The difference between the minimum value of the third distance and the first distance is greater than the difference between the minimum value of the third distance and the first distance.

  A seventh aspect of the stator (1) according to the present invention is the stator according to any one of the first, second, third, fourth, and sixth aspects, wherein the tooth portion (10) Axisymmetric with respect to the center (10N) of the root (10R).

  An eighth aspect of the stator (1) according to the present invention is the stator according to the fifth aspect, wherein the difference between the maximum value of the second distance and the first distance is the third distance. The difference between the minimum value of the third distance and the first distance is greater than the difference between the minimum value of the third distance and the first distance; The difference between the maximum value of the sixth distance and the first distance is the difference between the minimum value of the third distance and the first distance, the difference between the minimum value of the fourth distance and the first distance, and It is larger than any of the difference between the minimum value of the fifth distance and the first distance.

  A first aspect of the motor according to the present invention is the same distance as the stator (1) according to any one of the first to eighth aspects, about the central axis, and the inner surface of the tooth portion. A rotor (2) having an outer surface (200) facing (101; 102; 103) and rotatable in the positive angular direction (+ ψ).

  According to a second aspect of the motor of the present invention, there is provided an annular yoke (12) provided around a central axis and an annular yoke provided on the central axis side of the annular yoke and spaced apart from each other. Surrounded by a stator (1) having a plurality of wound tooth portions (10), an inner surface (101; 102; 103) of the tooth portion on the central axis side, and having a permanent magnet, And a rotor (2) that is rotatable about a central axis. And the clearance gap between the inner surface (101; 102; 103) facing the said rotor of the said tooth part and the said rotor is set so that the electromagnetic force which acts between both may become a sine wave form.

  The refrigerant compressor according to the present invention employs the first aspect or the second aspect of the motor according to the present invention.

  The cooling device according to the present invention employs the refrigerant compressor according to the present invention.

  The motor design method according to the present invention is a motor design method including a stator (1) and a rotor (2). The stator (1) is provided on an annular yoke (12) provided around a central axis and on the central axis side of the annular yoke, and armature windings are wound apart from each other. A plurality of teeth (10). The rotor (2) is surrounded by the inner surface (101; 102; 103) of the tooth portion on the central axis side, has a permanent magnet, and is rotatable around the central axis.

  In a first aspect of the motor designing method according to the present invention, the electromagnetic force acting between the inner surface (101; 102; 103) of the tooth portion and the rotor is made sinusoidal. design.

  According to a second aspect of the motor design method of the present invention, (a) a radius of the motor that is perpendicular to both the rotation direction (+ ψ) of the rotor and the central axis between the inner surface and the rotor. Obtaining a distance (L (θ, φ)) along the direction (D) for each rotational position (φ) of the rotor and each position (θ) of the inner surface; and (b) the inner surface. A step (S2) of obtaining an electromagnetic force (Fn (θ, φ)) generated in the normal direction of each for each rotational position (φ) of the rotor and each position (θ) of the inner surface; and (c) the electromagnetic A step of updating the distance by multiplying the distance by a square root of a value obtained by dividing the force by a desired function (G (θ, φ)) for the electromagnetic force (S4).

  According to a third aspect of the motor designing method of the present invention, (a) a radius of the motor that is perpendicular to both the rotation direction (+ ψ) of the rotor and the central axis between the inner surface and the rotor. Obtaining a distance (L (θ, ψ)) along the direction (D) for each rotational position (φ) of the rotor and each position (θ) of the inner surface; and (b) the inner surface. The maximum value (M (θ)) in a predetermined range of the rotational position (φ) of the rotor for the electromagnetic force (Fn (θ, φ)) generated in the normal line direction for each position (θ) of the inner surface Steps (S2, S3) for obtaining, and (c) a step of updating the distance by multiplying the distance by a square root of a value obtained by dividing the maximum value by a desired function (G (θ)) for the maximum value ( S4).

  According to a fourth aspect of the motor design method of the present invention, (a) a radius of the motor that is perpendicular to both the rotation direction (+ ψ) of the rotor and the central axis between the inner surface and the rotor. Obtaining a distance (L (θ, ψ)) along the direction (D) for each rotational position (φ) of the rotor and each position (θ) of the inner surface; and (b) the inner surface. Obtaining a magnetic flux density (Bn (θ, φ)) generated in the normal direction of each for each rotational position (φ) of the rotor and each position (θ) of the inner surface (S2), (c) the magnetic flux A step of updating the distance by multiplying the distance by a value obtained by dividing the density by a desired function (G (θ, φ)) for the magnetic flux density (S4).

  According to a fifth aspect of the motor design method of the present invention, (a) a radius of the motor that is perpendicular to both the rotation direction (+ ψ) of the rotor and the central axis between the inner surface and the rotor. Obtaining a distance (L (θ, ψ)) along the direction (D) for each rotational position (φ) of the rotor and each position (θ) of the inner surface; and (b) the inner surface. Obtaining the maximum value of the magnetic flux density (Bn (θ, φ)) generated in the normal direction of each in the predetermined range of the rotational position (φ) of the rotor for each position (θ) of the inner surface (S2, (S3) and (c) a step of updating the distance by multiplying the distance by a value obtained by dividing the maximum value by a desired function (G (θ)) for the maximum value (S4).

  A sixth aspect of the motor design method according to the present invention is the motor design method according to the third aspect and the fifth aspect, wherein the predetermined range is the entire rotational position (φ) of the rotor. Across the position.

  A motor design method according to a seventh aspect of the present invention is the motor design method according to the second to sixth aspects, wherein the steps (b) and (c) are repeatedly executed, and the distance is plural. Updated once (S7).

  An eighth aspect of the motor design method according to the present invention is the motor design method according to the second to seventh aspects, wherein the desired function (G (θ)) is the total number of teeth. m is proportional to sin (mθ / 2), where θ is the geometric position angle of the stator (1).

  A ninth aspect of the motor designing method according to the present invention is the motor designing method according to the eighth aspect, wherein the desired function (G (θ)) is such that the maximum value is the center of the tooth portion. It is proportional to the local maximum value (Fn0) given in the vicinity.

  A tenth aspect of a motor design method according to the present invention is a motor design method according to any one of the second to seventh aspects, wherein the desired function (G (θ)) is the maximum value. In the position (θ0) of the inner surface that gives the maximum value (Fn0) near the center of the tooth portion, the maximum value is set to the maximum value of the desired function (G (θ)), and the position (θ0 ) To the opposite side (−ψ) of the tooth portion to the rotation direction (+ ψ) of the rotor, the position (θ) of the inner surface decreases in a sine wave shape.

  An eleventh aspect of the motor designing method according to the present invention is the motor designing method according to any of the second to tenth aspects, wherein the desired function (G (θ)) It is set on the side (−ψ) opposite to the rotation direction (+ ψ) of the rotor from the center (10N) of the tooth portion. In the step (b), the desired function (G (θ)) is executed in a set range. (D) The method further includes a step which is executed after the steps (b) and (c) and sets the shape of the tooth portion in line symmetry with respect to the center (10N) of the tooth portion.

  According to the first to eighth aspects of the stator of the present invention and the first to second aspects of the motor of the present invention, the inner surface and rotation of the tooth portion when the rotor rotates in the positive angular direction. The electromagnetic force acting between the child and the sine wave can be made substantially sinusoidal to reduce motor vibration and noise.

  Accordingly, vibration and noise of the refrigerant compressor and the cooling device according to the present invention can be reduced.

  According to the motor design method of the present invention, when the rotor rotates, the electromagnetic force or magnetic flux density acting between the inner surface of the tooth portion and the rotor is set to a desired shape, for example, a sine wave, and the motor vibration , Noise can be reduced.

  In particular, according to the motor design method of the sixth aspect, the maximum value of the electromagnetic force or the magnetic flux density with respect to the rotational position of the rotor is set to a desired function form, so that teeth for reducing motor vibration and noise can be obtained. The gap / rotor gap can be easily designed.

  In particular, according to the motor design method of the seventh aspect, the gap between the tooth portion and the rotor can be designed more accurately.

  In particular, according to the motor design method according to the eighth aspect, the electromagnetic force or magnetic flux density acting between the inner surface of the tooth portion and the rotor when the rotor rotates is made substantially sinusoidal, Noise can be reduced.

  In particular, according to the motor designing method of the ninth aspect, a large torque can be obtained without greatly deforming the inner surface shape of the tooth portion from the cylindrical shape.

  In particular, according to the motor designing method according to the tenth to eleventh aspects, the inner surface shape of the tooth portion can be designed easily.

A. Basic concept of the present invention.
FIG. 1 is a cross-sectional view illustrating the configuration of a motor with a built-in permanent magnet that can be employed as an object of a motor design method according to the present invention. A positive direction in the axial direction z of the cylindrical coordinates is taken from the back to the front in the drawing, and a positive angular direction + ψ is adopted clockwise in the positive direction of the axial direction z.

  The motor with a built-in permanent magnet includes a stator 1 and a rotor 2, and the rotor 2 is surrounded by the stator 1.

  The stator 1 has an annular yoke 12 provided around a central axis parallel to the axial direction, and a plurality of tooth portions 10 provided on the central axis side of the annular yoke. The tooth portions 10 are separated from each other, and an armature winding (not shown) is wound around the space 11 between the tooth portions 10.

  The rotor 2 has a main body 20, and three kinds of gaps 21, 22, and 23 are provided in the main body 20. A permanent magnet (not shown) is embedded in the center of the gap 21. The end of the air gap 21 extends to the vicinity of the outer peripheral surface of the main body 20 so as to bypass the magnetic field at the end of the permanent magnet. The gap 22 is provided closer to the outer peripheral surface than the central portion of the gap 21. For the purpose of not only detouring the magnetic field but also maintaining the strength, the end of the gap 21 and the gap 22 may be filled with a nonmagnetic material.

  A shaft (not shown) is inserted into the gap 23 in parallel with the axial direction z, and the rotational torque of the rotor 2 is transmitted to the outside by the shaft.

  Hereinafter, the rotor 2 will be described as rotating in the positive angular direction + ψ, but the following discussion can be easily applied to the case where the rotor 2 rotates in the negative angular direction −ψ.

  FIG. 2 is an enlarged cross-sectional view showing the space between the inner surface 100 of the tooth portion 10 and the outer peripheral surface 200 of the rotor 2. The electromagnetic force between the inner surface 100 and the outer peripheral surface 200 depends on the distance L between them, the magnetomotive force V, the magnetic permeability μ, and the like. The distance L varies depending on the shape of the inner surface 100 and the shape of the outer peripheral surface 200. However, since both shapes are substantially cylindrical, the distance L is obtained along the direction perpendicular to both the rotation direction of the rotor (ie, positive angle direction + ψ) and the axial direction z, that is, the radial direction D of the motor. .

  However, in consideration of the shape of the inner surface 100 and the shape of the outer peripheral surface 200, the distance L depends on the geometric position angle θ set for the stator 1 and the position angle (mechanical angle) φ of the rotor 2 (both are A function along the positive angular direction + ψ). That is, the distance L (θ, ψ) is obtained along the radial direction D of the motor. The approximation of the shape of the inner surface 100 and the shape of the outer peripheral surface 200 is substantially cylindrical, but the function of the position angles θ, φ is used. Therefore, the shape of the inner surface 100 and the shape of the outer peripheral surface 200 are taken into consideration.

  Now, the normal component (hereinafter simply referred to as “electromagnetic force”) Fn of the electromagnetic attractive force acting between the rotor and the stator, which is the main factor of motor vibration and noise, is the inner surface 100 and the outer periphery. When the normal component of the magnetic flux density is Bn and the tangential component is Bt with respect to the surface 200, it is expressed as (Bn · Bn−Bt · Bt) / 2μ. Since the tangential component Bt on the inner surface 100 is smaller than the normal component Bn, the value obtained by taking each square difference is substantially equal to the square of the normal component Bn, as in the above calculation in parentheses. Therefore, the electromagnetic force Fn can be estimated as a value obtained by dividing the square of the normal component Bn on the inner surface 100 by twice the permeability μ.

  In order to reduce the vibration and noise of the motor, the electromagnetic force Fn (or the normal component Bn on the inner surface 100, which is proportional to the square root thereof) may be a desired function, for example, an arc or a sine wave. Since the magnetic flux density between the rotor and the stator is proportional to the magnetomotive force V and the magnetic permeability μ, if there is no magnetic saturation and the magnetomotive force V is constant without depending on the position angles θ and φ, the distance By setting L (θ, φ) to a constant value or a sine wave shape, vibration and noise can be reduced.

  However, the magnetomotive force V depends on the position angles θ and φ, and magnetic saturation occurs. The change in the magnetic permeability μ due to the angle dependency of the magnetomotive force V and magnetic saturation is particularly significant in a motor with a built-in permanent magnet having a complicated shape.

  FIG. 3 is a graph showing the angle dependence of the magnetomotive force, and FIG. 4 is a cross-sectional view showing the position of the magnetomotive force V and the flow of magnetic flux shown in FIG. Here, a case where the shape of the inner surface 100 and the shape of the outer peripheral surface 200 are cylindrical, and the distance L is a constant value is illustrated.

  The graph L1 in FIG. 3 shows the magnetomotive force V (θ, φ0) when the rotor 2 is in the position shown in FIG. 4 (the rotating mechanical angle of the rotor 2 at this time is φ0). The graph L2 indicates the maximum value of the magnetomotive force V during one rotation of the rotor 2, that is, the maximum value Vm (θ) of the magnetomotive force V with respect to the rotating machine angle φ of the magnetomotive force V (θ, φ).

  Therefore, in the present invention, the electromagnetic force Fn is once obtained by magnetic simulation, and the distance L (θ, φ) is corrected so as to approximate it to a desired function form, for example, a sine wave.

  Schematically describing the present invention, the clearance between the inner surface of the stator teeth and the rotor is set so as to have a sinusoidal electromagnetic force acting between them, so that the motor when the rotor rotates is set. It reduces vibration and noise.

B. First embodiment.
FIG. 5 is a flowchart showing a motor design method according to the first embodiment of the present invention. First, in step S1, a gap between the tooth portion 10 and the rotor 2, that is, a distance L (θ, φ) is obtained. This is determined by the shape of the inner surface 100 and the outer peripheral surface 200. As described above, the distance is determined along the radial direction D perpendicular to both the rotation direction of the rotor 2 and the central axis. The distance L (θ, ψ) is obtained for each rotation position (position angle) φ of the rotor 2 and for each position angle θ of the inner surface 100. For example, if the outer peripheral surface of the rotor 2 is cylindrical with the rotation center axis as the center, the distance L does not depend on the position of the rotor 2 and therefore depends only on the position angle θ.

  Next, in step S2, the electromagnetic force Fn (θ, φ) acting in the normal direction of the inner surface 100 is calculated using electromagnetic simulation. Furthermore, in step S3, the maximum value M (θ) of the electromagnetic force Fn (θ, φ) for the rotational position φ of the rotor 2 is obtained.

  FIG. 6 is a graph showing the results of the simulation. The vertical axis represents the electromagnetic force Fn, and the horizontal axis represents the position angle θ of the inner surface 100 of one tooth portion 10. It is a calculation result about the case where the inner surface 100 and the outer peripheral surface 200 are both cylindrical. A graph L11 shows the electromagnetic force Fn (θ, φ0) when the rotor 2 is at the rotational position φ0, and a graph L21 shows the maximum value M (θ).

  As shown in the graph L1 of FIG. 3, since the position angle θ is different if the tooth portion 10 is different, the magnetomotive force V is also different. However, in general, since all the tooth portions 10 are formed in the same shape, if the maximum value for the rotational position φ of the rotor 2 is taken, the same maximum value is obtained in any tooth portion 10 as shown in the graph L2 of FIG. The shape of the value is shown. Similarly to this, the graph L21 has the same shape in any tooth portion 10.

  Therefore, when the electromagnetic force Fn is set to a desired function form and vibration and noise are reduced, it is preferable to use the maximum value. This is because it is possible not only to design an electromagnetic force having a value larger than a desired function shape, but also to design any tooth portion 10 in the same shape.

  Now, for convenience of explanation, the tooth portion 10 has a root portion 10R that protrudes from the yoke 12 to the central axis, both on the central axis side of the root portion 10R, on the positive angle direction + ψ and on the negative angle direction −ψ side, respectively. It is divided into a first collar part 10P and a second collar part 10Q protruding from the root part 10R. The first collar 10P and the root 10R sandwich the boundary 10V, and the second collar 10Q and the root 10R sandwich the boundary 10W.

  The electromagnetic force Fn (θ) and its maximum value M (θ) exhibit a large maximum value near the end of the second flange 10Q opposite to the boundary 10W, that is, near the end on the negative angular direction −ψ side. . Then, it decreases as the position angle θ increases, and takes a minimum value in the vicinity of the boundary 10W. Then, the position angle θ increases as the position angle θ increases, and the local maximum value is taken again slightly before reaching the center 10N of the root portion (negative angle direction −ψ side). Thereafter, the position angle θ decreases substantially as the position angle θ increases, but exhibits a small maximum value in the vicinity of the end opposite to the boundary 10V of the first flange 10P, that is, in the vicinity of the end on the positive angle direction + ψ side.

  Returning to FIG. 5, step S4 is executed after step S3. Here, the distance between the inner surface of the tooth portion and the outer peripheral surface of the rotor is calculated using a desired function form G (θ). Specifically, the distance L (θ, φ) is multiplied by the square root of the value obtained by dividing the maximum value M (θ) by the desired function G (θ) for the maximum value, and a new distance L ′ (θ, φ).

  FIG. 7 is a graph illustrating step S4. The graph L0 shows the desired function G (θ) for the maximum value M (θ). In general, since the tooth portions 10 are equally arranged in the stator 1, the number of the tooth portions 10 is m and G (θ) = Fn0 · sin (mθ / 2). However, the maximum value Fn0 of the function G (θ) is the maximum value M (θ0) obtained at a position angle θ0 slightly before reaching the center 10N of the root when both the inner surface 100 and the outer peripheral surface 200 are cylindrical. ).

  Of course, in the present invention, the maximum value Fn0 is not limited to this case. However, in order to obtain a large torque without greatly changing the shape of the newly designed inner surface of the tooth portion 10 from the cylindrical shape, it is desirable to set the maximum value Fn0 as described above.

  The graph L21 also shown in FIG. 7 pulsates with respect to the graph L0. Therefore, if the inner surface 101 of the tooth portion 10 that reduces this pulsation is obtained, the noise of the motor can be reduced while the outer peripheral surface 200 of the rotor 2 is kept cylindrical. The specific calculation is as described in the description of step S4.

  In order to lower the local maximum value of the graph L21, the second angular portion 10Q from the negative angular direction −ψ side end to the position 10A, and from the position 10C to the first angular portion 10P positive angular direction + ψ side end. The inner surface 101 of the tooth portion 10 is further away from the central axis than the cylindrical inner surface 100. Further, in order to increase the minimum value of the graph L21, the inner surface 101 of the tooth portion 10 is made closer to the central axis than the cylindrical inner surface 100 between the position 10A and the position 10C. However, the distance from the central axis of the inner surface 101 is the same as the distance from the central axis of the inner surface 100 at the position 10B at the position angle θ0. As a result, the maximum value Fn (θ, φ) can be approximated to a desired function G (θ) having the maximum value M (θ0) as the maximum value.

  Returning to FIG. 5, the process proceeds from step S4 to step S5. Here, the maximum value M (θ) of the electromagnetic force is calculated again. FIG. 9 is a graph showing the result of recalculation. Graphs L21 and L0 show the maximum value M (θ) of the electromagnetic force on the cylindrical inner surface 100 and the desired function G (θ), respectively, and the graph L22 is obtained by executing steps S1 to S4 in sequence. The maximum value M (θ) after That is, the difference between the distance L (θ, φ) obtained in step S1 and the distance L ′ (θ, φ) obtained in step S4 appears as a difference between the graphs L12 and L22.

  The process proceeds from step S5 to step S6. In step S6, it is determined whether or not the difference between the new maximum value M (θ) and the desired function G (θ) is within an allowable range. The permissible range can be variously changed depending on the specifications of the motor to be designed and the mode of use.

  If the difference between the two is an allowable range, the shape of the tooth portion 10 is set in accordance with the distance L ′ (θ, φ) obtained in step S4. If it is not within the allowable range, the process proceeds to step S7, the distance L (θ, φ) is updated with the distance L ′ (θ, φ) obtained in step S4, and the process returns to step S2. In this way, steps S2 to S5 are repeated until the allowable range is reached.

  FIG. 8 is an enlarged cross-sectional view showing the configuration of the tooth portion 10 having the inner surface 101 facing the central axis (not shown). The shape of the inner surface 101 was determined based on the results obtained by repeating the steps S2 to S5 a plurality of times. However, the outer peripheral surface 200 of the rotor 2 is assumed to be cylindrical. The distance from the central axis of the inner surface 101 facing the central axis of the inner surface 101 can be described in detail as follows.

(i) The first position 10A in the second collar portion 10Q and the same first distance at the second position 10B between the boundary 10W and the center 10N of the root portion 10R are taken,
(ii) On the negative angle direction −ψ side from the first position 10A, a second distance larger than the first distance is taken,
(iii) A third distance smaller than the first distance is adopted between the first position 10A and the second position 10B,
(iv) Take a distance smaller than the first distance between the second position 10B and the third position 10C of the first flange portion 10P;
(v) On the positive angle direction + ψ side from the third position 10C, a distance larger than the first distance is taken.

  The above conditions (iv) and (v) can also be described as follows, with the center 10N as a boundary.

(iv) A fourth distance smaller than the first distance is adopted between the second position 10B and the center 10N of the root portion 10R.
(v) Taking a fifth distance smaller than the first distance between the center 10N of the root 10 and the third position 10C of the first flange 10P,
(vi) On the positive angle direction + ψ side from the third position 10C, a sixth distance larger than the first distance is taken.

  More specifically, the difference between the maximum value of the second distance (obtained in the vicinity of the end of the second flange 10Q opposite to the boundary 10W) and the first distance is the minimum value of the third distance (in the vicinity of the boundary 10W). And the difference between the first distance and the first distance.

  Further, the difference between the minimum value of the third distance and the first distance is larger than the difference between the minimum value of the fourth distance (obtained in the vicinity of the center 10N) and the first distance.

  Further, the difference between the maximum value of the sixth distance (obtained near the end opposite to the boundary 10V of the first flange 10P) and the first distance is the difference between the minimum value of the third distance and the first distance. It is larger than any of the difference, the difference between the minimum value of the fourth distance and the first distance, and the difference between the minimum value of the fifth distance (obtained in the vicinity of the boundary 10V) and the first distance.

  FIG. 10 is a graph showing the results when steps S2 to S5 are repeated a plurality of times. A graph L23 shows the maximum value M (θ) obtained by a plurality of recalculations, and graphs L21 and L0 are also shown.

  Compared with the graph L22 of FIG. 9, it can be seen that the graph L23 of FIG. 10 is closer to the desired function G (θ).

  FIG. 11 is a graph showing a change in resultant force obtained by adding the electromagnetic force Fn at each position of one tooth portion 10 of the stator 1 as a whole of the tooth portion 10. Here, since the case where the number of poles of the rotor 2 is six is shown, the case where the position angle φ is 0 to 60 degrees is illustrated. Even when the case where the inner surface 100 is used (before countermeasures) and the case where the inner surface 101 obtained by a plurality of repetitive calculations is used (after countermeasures) are compared, this graph clearly shows the resultant force of the electromagnetic force Fn. The difference is difficult to understand.

  Therefore, the frequency spectrum of the resultant force of the electromagnetic force Fn was obtained, and this was graphed in FIG. A comparison is made between the case where the inner surface 100 is used (before countermeasures) and the case where the inner surface 101 is used (after countermeasures). It can be seen that the harmonic component of the resultant force of the electromagnetic force Fn is clearly reduced after the countermeasure compared to before the countermeasure.

  As described above, according to the present embodiment, harmonics that are an even multiple of the electrical angular frequency of the electromagnetic attractive force can be reduced, and the motor shape, for example, the optimum shape of the tooth portion can be presented.

C. Second embodiment.
Also in this embodiment, the flowchart shown in FIG. 5 is adopted. FIG. 13 is a graph for explaining step S4 in the present embodiment. Similarly to FIG. 7, the graph L21 shows the maximum value M (θ) of the electromagnetic force Fn. On the other hand, the graph L01 shows a desired function G (θ) for the maximum value M (θ).

  In the present embodiment, for one tooth portion 10, the inner surface of the tooth portion 10 on the negative angle direction (−ψ) side from the position angle θ0 that gives the second largest maximum value M (θ). Improve the shape. Therefore, in the present embodiment, the desired function G (θ) coincides with the maximum value M (θ) on the positive angle direction (+ ψ) side with respect to the position angle θ0. By using such a function G (θ) and obtaining the distance L ′ according to the repeated calculation of the flowchart shown in FIG. 5, the electromagnetic force Fn generated on the negative angular direction (−ψ) side of the tooth portion 10 is obtained. Large fluctuations can also be suppressed.

  Here, the function G (θ) takes a maximum value Fn0 = M (θ0) at the position angle θ0, and has a shape that decreases in a sine wave shape on the negative angle direction (−ψ) side from the position angle θ0.

  FIG. 14 is a cross-sectional view illustrating the structure of the tooth portion 10 having the inner surface 103. When the inner surface 103 uses the function G (θ) shown in the graph L01 of FIG. 13 and the outer peripheral surface 200 of the rotor 2 has a cylindrical shape based on the distance L ′ obtained according to the flowchart shown in FIG. This is the inner surface of the tooth portion 10.

  The inner surface 103 is deformed from the cylindrical shape only on the negative angle direction −ψ side when viewed from the root portion 10N. When viewed from the root 10N, the positive angle direction + ψ side has a cylindrical shape. As described above, even when the shape is changed from the cylindrical shape only on the negative angle direction −ψ side when viewed from the root portion 10N, the maximum value M (θ that appears near the end portion on the negative angle direction −ψ side of the second flange portion 10Q. ) And the minimum value of the maximum value M (θ) appearing in the vicinity of the boundary 10W can be reduced.

  The inner surface 103 also satisfies the above conditions (i) to (iii). Specifically, the difference between the maximum value of the second distance and the first distance is larger than the difference between the minimum value of the third distance and the first distance.

  FIG. 15 is a cross-sectional view illustrating the structure of the tooth portion 10 having the inner surface 102. The inner surface 102 has a shape symmetrical with respect to the center 10N of the root portion 10R. By making the line symmetry in this way, the maximum value M (θ) of the electromagnetic force Fn in the entire tooth portion 10 can be easily approximated to the desired function G (θ) more easily than in the first embodiment. However, the desired function G (θ) is also axisymmetric with respect to the center 10N.

  In this case, it is sufficient that the step S4 is executed within a range in which the desired function (G (θ)) is set, while the step of setting the shape in line symmetry with respect to the center 10N of the root portion 10R of the tooth portion 10 is executed. .

  FIG. 16 is a graph showing the difference in the maximum value M (θ) of the electromagnetic force Fn due to the difference in the inner surface shape of the tooth portion 10. Graphs L21 and L23 are the same as those shown in FIG. 10 and correspond to the inner surface 100.101. A graph L24 indicates the maximum value M (θ) when the inner surface 102 is used. The position angle θN indicates the position of the center 10N of the root portion 10R of the tooth portion 10.

  Although the graph L24 is closer to a sine wave shape than the graph L21, it can be seen that the pulsation is larger on the positive angle direction + ψ side than the position angle θN compared to the graph L23.

  FIG. 17 is a graph showing a frequency spectrum of the resultant force of the electromagnetic force Fn. In FIG. 12, the graphs indicated as “before countermeasure” and “after countermeasure” are indicated as “before countermeasure” and “adopt inner surface 101”, respectively. In FIG. 17, the case where the inner surface 102 is further employed is also drawn. From this graph, it can be seen that both the inner surfaces 101 and 102 can reduce harmonics.

D. Third embodiment.
In the first embodiment and the second embodiment, the maximum value M (θ) of the electromagnetic force Fn is brought close to the desired function G (θ). However, the present invention is not limited to such an embodiment.

  For example, the electromagnetic force Fn (θ, φ) at a certain position angle φ of the rotor 2 may be brought close to a desired function G (θ). As a result, the electromagnetic force Fn (θ, φ) at a certain position angle φ can be suppressed.

  For example, the maximum value M (θ) may be the maximum value of the electromagnetic force Fn within a predetermined range of the position angle φ of the rotor 2. Thereby, the electromagnetic force in the vicinity of a certain position angle φ can be suppressed.

  Further, since the electromagnetic force Fn is proportional to the square of the normal component Bn of the magnetic flux density, the maximum value M (θ) of the normal component Bn of the magnetic flux density may be brought close to a desired function G (θ). In this case, in step S4, M (θ) / G (θ) is multiplied by the distance L (θ, φ) (without taking the square root) to obtain a new distance L ′ (θ, φ). Become.

  Further, the normal component Bn of the magnetic flux density at a certain position angle φ of the rotor 2 may be brought close to a desired function G (θ). Alternatively, the normal component Bn of the magnetic flux density within a predetermined range of the position angle φ of the rotor 2 may be adopted as the maximum value M (θ).

E. Application of the present invention.
By adopting the stator and motor according to the present invention, vibration and noise of the motor can be suppressed. Therefore, the vibration and noise of the refrigerant compressor equipped with such a motor are also suppressed, and the vibration and noise of the cooling device employing such a refrigerant compressor are also suppressed.

It is sectional drawing which illustrates the structure of the motor with a built-in permanent magnet which can be employ | adopted as the object of the motor design method concerning this invention. 3 is an enlarged cross-sectional view showing a space between an inner surface 100 of a tooth portion 10 and an outer peripheral surface 200 of a rotor 2. FIG. It is a graph which shows the angle dependence of a magnetomotive force. It is sectional drawing which shows the position of the magnetomotive force V shown by FIG. 3, and the flow of magnetic flux. It is a flowchart which shows the design method of the motor concerning the 1st Embodiment of this invention. It is a graph which shows the effect of the design method of the motor concerning a 1st embodiment of the present invention. It is a graph explaining step S4 of the motor design method according to the first embodiment of the present invention. It is sectional drawing which expands and shows the structure of the tooth | gear part 10 which has the inner surface 101. FIG. It is a graph which shows the result of step S5. It is a graph which shows a result at the time of performing Steps S2-S5 by repeating a plurality of times. 4 is a graph showing changes in electromagnetic force Fn (θ1, φ) according to the rotation of a rotor 2. It is a graph which shows the frequency spectrum of the electromagnetic force Fn in the 1st Embodiment of this invention. It is a graph explaining step S4 of the motor design method according to the second embodiment of the present invention. 3 is a cross-sectional view illustrating the structure of a tooth portion 10 having an inner surface 103. FIG. 3 is a cross-sectional view illustrating the structure of a tooth portion 10 having an inner surface 102. FIG. It is a graph which shows the difference in the maximum value M ((theta)) of the electromagnetic force Fn by the difference in the inner surface shape of the tooth | gear part 10. FIG. It is a graph which shows the frequency spectrum of the electromagnetic force Fn in the 2nd Embodiment of this invention.

Explanation of symbols

10 tooth part 10A 1st position 10B 2nd position 10C 3rd position 10N center of root 10P first collar part 10Q second collar part 10R root part 10V boundary between root part and first collar part 10W between root part and second collar part Boundary 101, 102, 103 Inner surface of tooth part + ψ Positive angular direction -ψ Negative angular direction

Claims (23)

An annular yoke (12) provided around the central axis;
A plurality of teeth (10) provided on the central axis side of the annular yoke and spaced apart from each other;
The tooth portion includes a root portion (10R) protruding from the yoke to the central axis,
A first flange portion (10P) which is provided on the central axis side of the root portion and protrudes from the root portion in the positive angular direction (+ ψ) side when the central axis is taken in the axial direction (z); A second flange portion (10Q) protruding from the root portion on the angle direction (−ψ) side of
The distance from the central axis of the inner surface (101; 102; 103) facing the central axis of the tooth portion is:
(i) a first position (10A) in the second collar part, and a second position (10B) between a boundary (10W) between the root part and the second collar part and a center (10N) of the root part Take equal first distances at
(ii) taking a second distance greater than the first distance on the negative direction side of the first position;
(iii) taking a third distance smaller than the first distance between the first position and the second position;
Stator (1). The distance from the central axis of the inner surface (103) is
(iv) The stator (1) according to claim 1, wherein the first distance is taken on the positive angle direction (+ ψ) side from the second position (10B).   3. The difference between the maximum value of the second distance and the first distance is greater than the difference between the minimum value of the third distance and the first distance. 4. Stator (1). The distance from the central axis of the inner surface (101; 102) is
(iv) The stator (1) according to claim 1, wherein a fourth distance smaller than the first distance is taken between the second position (10B) and the center (10N) of the root (10R). The distance from the central axis of the inner surface (101) is
(v) taking a fifth distance smaller than the first distance between the center (10N) of the root portion (10R) and a third position (10C) in the first flange;
(vi) taking a sixth distance larger than the first distance on the positive direction (+ ψ) side from the third position;
The stator (1) according to claim 4. The difference between the maximum value of the second distance and the first distance is larger than the difference between the minimum value of the third distance and the first distance,
The stator (1) according to claim 4, wherein a difference between the minimum value of the third distance and the first distance is larger than a difference between the minimum value of the fourth distance and the first distance.   The stator (1) according to any one of claims 1, 2, 3, 4 and 6, wherein the tooth portion (10) is axisymmetric with respect to the center (10N) of the root portion (10R). The difference between the maximum value of the second distance and the first distance is larger than the difference between the minimum value of the third distance and the first distance,
The difference between the minimum value of the third distance and the first distance is larger than the difference between the minimum value of the fourth distance and the first distance,
The difference between the maximum value of the sixth distance and the first distance is the difference between the minimum value of the third distance and the first distance, the difference between the minimum value of the fourth distance and the first distance, and Greater than any of the differences between the minimum value of the fifth distance and the first distance;
Stator (1) according to claim 5. A stator (1) according to any one of claims 1 to 8,
Rotation having an outer surface (200) facing the inner surface (101; 102; 103) of the tooth portion and rotating in the positive angular direction (+ ψ) at the same distance around the central axis A motor comprising a child (2). An annular yoke (12) provided around the central axis;
A plurality of tooth portions (10) provided on the central axis side of the annular yoke and spaced apart from each other and wound with an armature winding;
A stator (1) having
A rotor (2) surrounded by an inner surface (101; 102; 103) on the central axis side of the tooth portion, having a permanent magnet, and rotatable about the central axis;
The motor, wherein the gap between the inner surface (101; 102; 103) of the tooth portion facing the rotor and the rotor is set so that the electromagnetic force acting between the two is sinusoidal.   A refrigerant compressor employing the motor according to claim 9.   A cooling device employing the refrigerant compressor according to claim 11. An annular yoke (12) provided around the central axis;
A plurality of tooth portions (10) provided on the central axis side of the annular yoke and spaced apart from each other and wound with an armature winding;
A stator (1) having
A motor design method comprising a rotor (2) surrounded by an inner surface (101; 102; 103) on the central axis side of the tooth portion, having a permanent magnet, and rotatable about the central axis. There,
A motor design method in which a gap between the inner surface (101; 102; 103) of the tooth portion and the rotor is designed so that an electromagnetic force acting between the teeth is made sinusoidal. An annular yoke (12) provided around the central axis;
A plurality of tooth portions (10) provided on the central axis side of the annular yoke and spaced apart from each other and wound with an armature winding;
A stator (1) having
A motor design method comprising a rotor (2) surrounded by an inner surface (101; 102; 103) on the central axis side of the tooth portion, having a permanent magnet, and rotatable about the central axis. There,
(A) Distance (L (θ, φ) along the radial direction (D) of the motor perpendicular to both the rotation direction (+ ψ) of the rotor and the central axis between the inner surface and the rotor ) For each rotational position (φ) of the rotor and each position (θ) of the inner surface (S1),
(B) obtaining an electromagnetic force (Fn (θ, φ)) generated in a normal direction of the inner surface for each rotational position (φ) of the rotor and each position (θ) of the inner surface (S2);
(C) a step of updating the distance by multiplying the distance by a square root of a value obtained by dividing the electromagnetic force by a desired function (G (θ, φ)) for the electromagnetic force (S4). Design method. An annular yoke (12) provided around the central axis;
A plurality of tooth portions (10) provided on the central axis side of the annular yoke and spaced apart from each other and wound with an armature winding;
A stator (1) having
A motor design method comprising a rotor (2) surrounded by an inner surface (101; 102; 103) on the central axis side of the tooth portion, having a permanent magnet, and rotatable about the central axis. There,
(A) Distance (L (θ, ψ) along the radial direction (D) of the motor perpendicular to both the rotation direction (+ ψ) of the rotor and the central axis between the inner surface and the rotor ) For each rotational position (φ) of the rotor and each position (θ) of the inner surface (S1),
(B) The maximum value (M (θ)) in a predetermined range of the rotational position (φ) of the rotor of the electromagnetic force (Fn (θ, φ)) generated in the normal direction of the inner surface is the position of the inner surface. Steps (S2, S3) for each (θ),
(C) A method of designing a motor comprising the step of updating the distance by multiplying the distance by a square root of a value obtained by dividing the maximum value by a desired function (G (θ)) for the maximum value (S4). . An annular yoke (12) provided around the central axis;
A plurality of tooth portions (10) provided on the central axis side of the annular yoke and spaced apart from each other and wound with an armature winding;
A stator (1) having
A motor design method comprising a rotor (2) surrounded by an inner surface (101; 102; 103) on the central axis side of the tooth portion, having a permanent magnet, and rotatable about the central axis. There,
(A) Distance (L (θ, ψ) along the radial direction (D) of the motor perpendicular to both the rotation direction (+ ψ) of the rotor and the central axis between the inner surface and the rotor ) For each rotational position (φ) of the rotor and each position (θ) of the inner surface (S1),
(B) obtaining a magnetic flux density (Bn (θ, φ)) generated in the normal direction of the inner surface for each rotational position (φ) of the rotor and each position (θ) of the inner surface (S2);
(C) Multiplying the distance by a value obtained by dividing the magnetic flux density by a desired function (G (θ, φ)) for the magnetic flux density, and updating the distance (S4). . An annular yoke (12) provided around the central axis;
A plurality of tooth portions (10) provided on the central axis side of the annular yoke and spaced apart from each other and wound with an armature winding;
A stator (1) having
A motor design method comprising a rotor (2) surrounded by an inner surface (101; 102; 103) on the central axis side of the tooth portion, having a permanent magnet, and rotatable about the central axis. There,
(A) Distance (L (θ, ψ) along the radial direction (D) of the motor perpendicular to both the rotation direction (+ ψ) of the rotor and the central axis between the inner surface and the rotor ) For each rotational position (φ) of the rotor and each position (θ) of the inner surface (S1),
(B) The maximum value of the magnetic flux density (Bn (θ, φ)) generated in the normal direction of the inner surface in a predetermined range of the rotational position (φ) of the rotor is obtained for each position (θ) of the inner surface. Steps and (S2, S3),
(C) A method for designing a motor, comprising the step of updating the distance by multiplying the distance by a value obtained by dividing the maximum value by a desired function (G (θ)) for the maximum value (S4).   18. The motor design method according to claim 15, wherein the predetermined range covers all positions of the rotational position (φ) of the rotor.   The motor design method according to any one of claims 14 to 18, wherein the steps (b) and (c) are repeatedly executed to update the distance a plurality of times (S7).   The desired function (G (θ)) is proportional to sin (mθ / 2), where m is the total number of teeth and θ is the geometric position angle for the stator (1). The motor design method according to any one of claims 14 to 19.   21. The motor design method according to claim 20, wherein the desired function (G (θ)) is proportional to a maximum value (Fn0) that the maximum value is given in the vicinity of the center of the tooth portion. The desired function (G (θ)) is
In the position (θ0) of the inner surface where the maximum value gives a maximum value (Fn0) in the vicinity of the center of the tooth portion, the maximum value is the maximum value of the desired function (G (θ)),
Decreasing in a sinusoidal shape as the position (θ) of the inner surface moves from the position (θ0) of the inner surface to the opposite side (−ψ) of the rotation direction (+ ψ) of the rotor of the tooth portion,
The motor design method according to any one of claims 14 to 19. The desired function (G (θ)) is set on the opposite side (−ψ) from the rotation direction (+ ψ) of the rotor from the center (10N) of each tooth portion,
In the step (c), the desired function (G (θ)) is executed in a set range,
23. The method of claim 14, further comprising the step of (d) performing the steps (b) and (c) and setting the shape of the tooth portion in line symmetry with respect to the center (10N) of the tooth portion. The motor design method according to any one of the above.

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