Rotary electric machine

Abstract

To reduce a noise of a rotary electric machine, generated due to a vibration in accordance with a driving of the rotary electric machine.SOLUTION: A rotary electric machine 10 comprises: a rotor 19 that includes a magnetic body 30, and a shaft member integrally rotated with the magnetic body 30; and a stator 60 having a stator core 61 and a coil 62. The stator core 61 includes: a cylinder yoke 71 extended to a shaft direction X; and a teeth 72 extended from the yoke 71 while being positioned into an inner part of the yoke 71. When a dimension to a first intersection point P1 of an orthogonal axial line L2 from a center point P and an outer peripheral surface 71a of the yoke 71 is La / 2, a dimension to a second intersection point P2 of the orthogonal axial line L2 from the center point P and an end surface 76 of the teeth 72 is Lb / 2, a thickness of the yoke 71 on the orthogonal axial line L2 is Lc, and a length of the teeth 72 on the orthogonal axial line L2 is Ld, the following equations are satisfied: La / 2-Lb / 2=Lc+Ld, 0.15≤Lb / La≤0.35, and Lc / Ld≥0.35.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine. [Background technology]

[0002] The rotating electric machine described in Patent Document 1 includes a rotor and a stator. The rotor has a magnetic body and a shaft member that rotates integrally with the magnetic body. The stator has a stator core and coils. A known stator core has a yoke and teeth. The yoke extends in the axial direction of the shaft member and is cylindrical with the axis of the shaft member as its center. If a line extending in an orthogonal direction perpendicular to the axis of the shaft member is taken as an orthogonal axis, the teeth are located inside the yoke and extend from the yoke along the orthogonal axis. The coils are wound around the teeth. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-209354 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of a rotating electric machine in which the shaft member rotates at a high speed, the dimension of the shaft member in the orthogonal direction may be reduced in order to suppress rotor loss. In this case, in order to ensure an appropriate value for the dimension of the gap between the shaft member and the end face of the teeth in the orthogonal direction, it is necessary to reduce the dimension from the center point, which is a point on the orthogonal axis at the center of the yoke, to the intersection point of the orthogonal axis and the end face of the teeth in accordance with the dimension of the shaft member. In addition, since it is necessary to ensure an area occupied by the coil inside the yoke, there is a limit to reducing the dimension from the center point to the intersection point of the orthogonal axis and the outer peripheral surface of the yoke. As a result, the ratio of the dimension from the center point to the intersection point of the orthogonal axis and the end face of the teeth to the dimension from the center point to the intersection point of the orthogonal axis and the outer peripheral surface of the yoke is a value within a specific range. In this way, in a rotating electric machine in which the above ratio is a value within a specific range, the thickness of the yoke decreases as the length of the teeth increases. However, depending on the length of the teeth and the thickness of the yoke, the natural frequency of the rotating electric machine decreases, and the natural frequency may become a value within the range of the operating frequency. When the natural frequency is within the range of the operating frequency, resonance occurs when the rotating electric machine is driven, which may result in noise caused by vibration. Therefore, it has been desired to reduce noise caused by such vibration in the rotating electric machine.

[0005] Furthermore, when the coil is wound around the teeth by distributed winding, the electromagnetic force that is the source of the excitation force acting on the teeth is distributed to each tooth. In contrast, when the coil is wound around the teeth by concentrated winding, the electromagnetic force is not distributed to each tooth as in the case where the coil is wound around the teeth by distributed winding, and a large electromagnetic force acts on the teeth. Therefore, when the coil is wound around the teeth by concentrated winding, the excitation force acting on the teeth is larger than when the coil is wound around the teeth by distributed winding. This may cause noise due to vibration of the teeth. Thus, it has been desired to reduce noise due to vibration even in rotating electric machines in which the coil is wound around the teeth by concentrated winding. [Means for solving the problem]

[0006] A rotating electric machine that solves the above problem is a rotating electric machine comprising: a rotor having a magnetic body and a shaft member that rotates integrally with the magnetic body; a stator having a stator core and a coil; and a bearing that rotatably supports the shaft member with respect to a housing that accommodates the rotating electric machine. When a line extending in an orthogonal direction perpendicular to the axis of the shaft member is taken as an orthogonal axis, the stator core extends in the axial direction of the shaft member and has a cylindrical yoke centered on the axis, and teeth that are located inside the yoke and extend from the yoke along the orthogonal axis. The coil is wound around the teeth using concentrated winding, and is characterized in that, assuming that the point on the orthogonal axis at the center of the yoke is the center point, the dimension from the center point to the intersection of the orthogonal axis and the outer peripheral surface of the yoke is La / 2, the dimension from the center point to the intersection of the orthogonal axis and the end face of the tooth is Lb / 2, the thickness of the yoke on the orthogonal axis is Lc, and the length of the tooth on the orthogonal axis is Ld, then La / 2-Lb / 2=Lc+Ld, 0.15≦Lb / La≦0.35, and Lc / Ld≧0.35.

[0007] According to the above configuration, the ratio of the length of the teeth to the dimensions of the stator core in the orthogonal direction is smaller than when Lc / Ld<0.35, so that the teeth are less likely to vibrate when the rotating electric machine is driven. Also, compared to when Lc / Ld<0.35, the natural frequency of the rotating electric machine can be increased to a value outside the range of the operating frequency, so that the occurrence of resonance caused by the operation of the rotating electric machine can be suppressed. Therefore, in a rotating electric machine in which the coil is wound around the teeth by concentrated winding and noise caused by vibration of the teeth is likely to occur, the noise of the rotating electric machine caused by the vibration caused by the operation of the rotating electric machine can be reduced.

[0008] In a rotating electric machine, slots, which are spaces located between adjacent teeth in the circumferential direction of the yoke, are formed inside the stator core, six of the slots are lined up in the circumferential direction of the yoke, and the magnetic body may be magnetized in the perpendicular direction and have two poles.

[0009] According to the above configuration, the stator has a vibration mode in which the stator deforms in a circular quadratic manner. Therefore, compared to a case in which the stator has a vibration mode in which the stator deforms in a manner other than a circular quadratic manner, noise generated when the rotating electric machine is driven tends to be louder. Therefore, by reducing the noise of the rotating electric machine generated due to the vibrations generated when the rotating electric machine is driven, it is possible to reduce noise even in a rotating electric machine that tends to generate loud noise as described above.

[0010] In a rotating electric machine, the teeth have an axial tooth main body portion extending from the yoke in the orthogonal direction and a tooth tip portion, and of both ends of the tooth main body portion in the orthogonal direction, the end connected to the yoke is defined as a first end and the end opposite the first end is defined as a second end, the tooth tip portion extends in a circumferential direction of the yoke from the second end, and the coil is wound around the part of the tooth main body portion that is on the yoke side in the orthogonal direction, and does not necessarily have to be wound around the part on the tooth tip side in the orthogonal direction.

[0011] According to the above configuration, the coil is wound around the portion of the tooth main body that is on the yoke side in the orthogonal direction, and is not wound around the portion on the tooth tip side in the orthogonal direction. Therefore, compared to when the coil is wound around the entire tooth main body in the orthogonal direction, the center of gravity of the tooth around which the coil is wound is shifted to the yoke side in the orthogonal direction, so that the vibration of the tooth caused by the operation of the rotating electric machine is further reduced. Therefore, the noise of the rotating electric machine caused by the vibration caused by the operation of the rotating electric machine can be further reduced. Effect of the Invention

[0012] According to the present invention, it is possible to reduce noise from a rotating electric machine that is generated due to vibrations accompanying driving of the rotating electric machine. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is a schematic diagram showing a cross section of a rotating electric machine; [Diagram 2]FIG. [Diagram 3] 1 is a graph showing the natural frequency and OA value in a comparative example and an example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a rotating electric machine according to an embodiment will be described with reference to the drawings. <Basic configuration of rotating electric machine> As shown in Fig. 1, the rotating electric machine 10 includes a rotor 19 and a stator 60. The rotating electric machine 10 is accommodated in a housing 11. The housing 11 includes a first housing component 12 and a plate-shaped second housing component 13. The first housing component 12 and the second housing component 13 are made of metal. The first housing component 12 and the second housing component 13 are made of aluminum, for example.

[0015] The first housing component 12 has a plate-shaped bottom wall 12a and a peripheral wall 12b extending in a cylindrical shape from the outer circumferential end of the bottom wall 12a. Of the openings at both ends of the peripheral wall 12b, one opening is closed by the bottom wall 12a, and the other opening is closed by the second housing component 13. The second housing component 13 is connected to the first housing component 12 with the opening of the peripheral wall 12b closed.

[0016] The first housing component 12 has a cylindrical first boss portion 12c. The first boss portion 12c protrudes from the inner surface of the bottom wall 12a. The second housing component 13 has a cylindrical second boss portion 13c. The second boss portion 13c protrudes from the inner surface of the second housing component 13. The axis of the first boss portion 12c, the axis of the second boss portion 13c, and the axis of the peripheral wall 12b of the first housing component 12 are aligned with each other.

[0017] The rotating electric machine 10 includes a bearing 14. The bearing 14 is disposed on the inner circumferential surface of the first boss portion 12c and the inner circumferential surface of the second boss portion 13c. <Rotor configuration> The rotor 19 is located inside the housing 11. The rotor 19 has a magnetic body 30 and a shaft member 40 that rotates integrally with the magnetic body 30. For example, the rotor 19 has a cylindrical member 20.

[0018] The tubular member 20 is cylindrical. The tubular member 20 is made of, for example, metal. The axis of the tubular member 20 coincides with the axis of the first boss portion 12c and the axis of the second boss portion 13c. Hereinafter, the direction in which the axis of the tubular member 20 extends is referred to as the axial direction X. The inner peripheral surface of the tubular member 20 is referred to as the tubular member inner surface 20a. The outer peripheral surface of the tubular member 20 is referred to as the tubular member outer surface 20b.

[0019] Of the openings at both ends of the tubular member 20 in the axial direction X, the opening at one end is referred to as a first opening 21, and the opening at the other end is referred to as a second opening 22. Both the first opening 21 and the second opening 22 are circular holes. The inner diameter of the tubular member 20 has the same dimension throughout the axial direction X, including the first opening 21 and the second opening 22. Hereinafter, the direction in which the inner diameter of the tubular member 20 extends is referred to as the radial direction Y.

[0020] <Magnetic material composition> The magnetic body 30 is, for example, cylindrical. The magnetic body 30 of this embodiment is a permanent magnet. The magnetic body 30 is magnetized in the radial direction Y. The magnetic body 30 is composed of a first magnetic part 30c and a second magnetic part 30d. The first magnetic part 30c is magnetized to the N pole. The second magnetic part 30d is magnetized to the S pole. That is, the magnetic body 30 has two poles. The first magnetic part 30c is, for example, a semi-cylindrical part occupying one side of the magnetic body 30 in the radial direction Y. The second magnetic part 30d is, for example, a semi-cylindrical part occupying the other side of the magnetic body 30 in the radial direction Y.

[0021] The magnetic body 30 is disposed inside the cylindrical member 20. The axis of the magnetic body 30 coincides with the axis of the cylindrical member 20. The diameter of the magnetic body 30 is the same as the inner diameter of the cylindrical member 20. The direction in which the diameter of the magnetic body 30 extends is the same as the radial direction Y. The magnetic body 30 is, for example, press-fitted into the cylindrical member 20. The outer surface 30a of the magnetic body 30 is in close contact with the cylindrical member inner surface 20a, thereby fixing the magnetic body 30 to the cylindrical member inner surface 20a. Of both ends of the magnetic body 30 in the axial direction X, one end is referred to as a first magnetic body end 31, and the other end is referred to as a second magnetic body end 32.

[0022] <Configuration of shaft member> The rotor 19 has, for example, two shaft members 40. One of the shaft members 40 is also referred to as a first shaft member 41, and the other shaft member 40 is also referred to as a second shaft member 51. The first shaft member 41 and the second shaft member 51 are, for example, cylindrical. The first shaft member 41 and the second shaft member 51 are, for example, made of metal.

[0023] The diameters of the first shaft member 41 and the second shaft member 51 are the same as the inner diameter of the tubular member 20. The direction in which the diameters of the first shaft member 41 and the second shaft member 51 extend is the same as the radial direction Y. The axis of the first shaft member 41 and the axis of the second shaft member 51 coincide with each other. The axis of the first shaft member 41 and the second shaft member 51 corresponds to the axis of the shaft member 40. The axis of the shaft member 40 is called the axis L1. The axis L1 coincides with the axis of the tubular member 20, the axis of the first boss portion 12c, and the axis of the second boss portion 13c. The direction in which the axis L1 extends is the same as the axial direction X. The axial direction X corresponds to the axial direction of the shaft member 40. The radial direction Y corresponds to the orthogonal direction perpendicular to the axis L1.

[0024] The first shaft member 41 and the second shaft member 51 are press-fitted into the cylindrical member 20. The first shaft member 41 has a first press-fit portion 43 press-fitted into the cylindrical member 20, and a first exposed portion 42 that is not press-fitted into the cylindrical member 20. The second shaft member 51 has a second press-fit portion 53 press-fitted into the cylindrical member 20, and a second exposed portion 52 that is not press-fitted into the cylindrical member 20.

[0025] The first press-fit portion 43 is located further inside the tubular member 20 than the first opening 21 of the tubular member 20 in the axial direction X. The first exposed portion 42 is exposed to the outside of the tubular member 20 from the first opening 21 of the tubular member 20 in the axial direction X. The second press-fit portion 53 is located further inside the tubular member 20 than the second opening 22 of the tubular member 20 in the axial direction X. The second exposed portion 52 is exposed to the outside of the tubular member 20 from the second opening 22 of the tubular member 20 in the axial direction X.

[0026] The outer peripheral surface of the first exposed portion 42 is supported by a bearing 14 arranged on the inner peripheral surface of the first boss portion 12c. As a result, the first shaft member 41 is rotatably supported with respect to the housing 11. The outer peripheral surface of the second exposed portion 52 is supported by a bearing 14 arranged on the inner peripheral surface of the second boss portion 13c. As a result, the second shaft member 51 is rotatably supported with respect to the housing 11. Therefore, the bearing 14 rotatably supports the shaft member 40 with respect to the housing 11 that accommodates the rotating electric machine 10.

[0027] A first outer peripheral surface 43a which is the outer peripheral surface of the first press-fit portion 43 and a second outer peripheral surface 53a which is the outer peripheral surface of the second press-fit portion 53 are in close contact with the cylindrical member inner surface 20a. As a result, the first shaft member 41 and the second shaft member 51 are fixed to the cylindrical member inner surface 20a. The first shaft member 41 and the second shaft member 51 are rotatable together with the cylindrical member 20 and the magnetic body 30.

[0028] The first press-fit portion 43 and the second press-fit portion 53 are adjacent to the magnetic body 30 in the axial direction X. In other words, the shaft member 40 and the magnetic body 30 are adjacent to each other in the axial direction X. An end portion of the first press-fit portion 43 in the axial direction X is referred to as a first shaft member end 44. An end portion of the second press-fit portion 53 in the axial direction X is referred to as a second shaft member end 54. The first shaft member end 44 is adjacent to the first magnetic body end 31 in the axial direction X. The second shaft member end 54 is adjacent to the second magnetic body end 32 in the axial direction X.

[0029] The first shaft member end 44 may be in contact with the first magnetic body end 31, or may be spaced apart from the first magnetic body end 31 in the axial direction X. The second shaft member end 54 may be in contact with the second magnetic body end 32, or may be spaced apart from the second magnetic body end 32 in the axial direction X.

[0030] The second exposed portion 52 penetrates the second housing component 13 and extends in the axial direction X between the inside and outside of the housing 11. A rotating member (not shown) that rotates integrally with the second shaft member 51 may be connected to an end of the second exposed portion 52 located outside the housing 11. In this case, the rotation of the second shaft member 51 is transmitted to the rotating member as a driving force, thereby driving the rotating member to rotate. The rotating electric machine 10 in this embodiment is, for example, a so-called high-speed compressor equipped with an impeller as a rotating member. Therefore, in the rotating electric machine 10 in this embodiment, the shaft member 40 rotates at high speed.

[0031] <Stator configuration> The stator 60 is located inside the housing 11. The stator 60 is located outside the rotor 19 in the radial direction Y. The stator 60 has a stator core 61 and a coil 62.

[0032] <Stator core configuration> The stator core 61 is formed, for example, by stacking a plurality of electromagnetic steel sheets 63 in the axial direction X. The stator core 61 has a first side surface 61a at one end in the axial direction X and a second side surface 61b at the other end in the axial direction X.

[0033] As shown in Fig. 2, a line extending in a radial direction Y as an orthogonal direction perpendicular to the axis L1 of the shaft member 40 is defined as an orthogonal axis L2. The stator core 61 has, for example, a yoke 71 extending in the axial direction X and teeth 72 located within the yoke 71. The yoke 71 is tubular with the axis L1 as its center. The yoke 71 is cylindrical, for example. The stator core 61 has, for example, six teeth 72. The teeth 72 extend from the yoke 71 along the orthogonal axis L2.

[0034] Slots S1 are formed inside the stator core 61. The slots S1 are spaces located between the teeth 72 that are adjacent to each other in the circumferential direction of the yoke 71. Six slots S1 are arranged in the circumferential direction of the yoke 71.

[0035] The teeth 72 have a teeth main body 73 and a teeth tip 74. The teeth main body 73 is axially shaped and extends in the radial direction Y as the orthogonal direction from the yoke 71. Of both ends of the teeth main body 73 in the radial direction Y as the orthogonal direction, the end connected to the yoke 71 is a first end 73a, and the end opposite the first end 73a is a second end 73b. The teeth tip 74 extends from the second end 73b in the circumferential direction of the yoke 71.

[0036] The tooth tip portion 74 has an end face 76 at the end opposite to the end connected to the tooth main body portion 73, among both ends of the tooth tip portion 74 in the radial direction Y. The end face 76 of the tooth tip portion 74 defines an internal space S2. The end face 76 of the tooth tip portion 74 is located at the tip of the tooth 72 in the radial direction Y, which is the perpendicular direction. Therefore, hereinafter, the end face 76 is also referred to as the end face 76 of the tooth 72. The end face 76 of the tooth tip portion 74 is a surface that extends in a curved manner so as to be parallel to the inner peripheral surface of the yoke 71. The internal space S2 penetrates in the axial direction X. The end faces 76 of the six teeth 72 define a cylindrical internal space S2 inside the stator core 61.

[0037] The magnetic body 30 is located in the internal space S2. In detail, the magnetic body 30 and the cylindrical member 20 are located in the internal space S2. In the cross-sectional shape of the stator core 61 and the cylindrical member 20 perpendicular to the axial direction X, the end face 76 of the tooth tip portion 74 faces the cylindrical member outer surface 20b. The end face 76 of the tooth tip portion 74 faces the outer surface 30a of the magnetic body 30 via the cylindrical member 20. The end face 76 of the tooth tip portion 74 is a curved surface extending along the cylindrical member outer surface 20b. The end face 76 of the tooth tip portion 74 is separated from the cylindrical member outer surface 20b in the radial direction Y. Therefore, the end face 76 of the tooth tip portion 74 is also separated from the outer surface 30a of the magnetic body 30 in the radial direction Y. The end face 76 of the tooth tip portion 74 and the outer surface 30a of the magnetic body 30 are parallel to each other.

[0038] A part of the inner peripheral surface of the yoke 71 and a part of the outer surface of the tooth main body 73 are covered with a resin member 75. The resin member 75 is provided for each tooth 72. 1, an outer peripheral surface 71a of the yoke 71 is fixed to an inner peripheral surface of the peripheral wall 12b of the first housing component 12. By fixing the yoke 71 to the first housing component 12 in this manner, the stator core 61 is fixed to the housing 11.

[0039] <Coil configuration> 2, the coil 62 is wound around the teeth 72 by concentrated winding. The coil 62 is wound around the tooth main body 73 from the outside of the resin member 75. The stator core 61 and the coil 62 are insulated from each other by the resin member 75.

[0040] The coil 62 is wound around a portion of the tooth main body 73 that faces the yoke 71 in the radial direction Y as the orthogonal direction, and is not wound around a portion of the tooth tip portion 74 in the radial direction Y as the orthogonal direction. As a result, the coil 62 is wound around the tooth main body 73 at a position that is biased toward the yoke 71 side relative to the tooth tip portion 74 side in the radial direction Y.

[0041] Coil 62 includes U-phase coil 62U, V-phase coil 62V, and W-phase coil 62W. A portion of each of U-phase coil 62U, V-phase coil 62V, and W-phase coil 62W wound around teeth 72 passes through slot S1. Each of U-phase coil 62U, V-phase coil 62V, and W-phase coil 62W is electrically connected to an inverter (not shown). Rotor 19 is rotatable when power from the inverter is supplied to U-phase coil 62U, V-phase coil 62V, and W-phase coil 62W.

[0042] 1, the coil 62 has a first coil end 62a and a second coil end 62b. The first coil end 62a protrudes from a first side surface 61a of the stator core 61 toward the bottom wall 12a of the first housing component 12. The second coil end 62b protrudes from a second side surface 61b of the stator core 61 toward the second housing component 13. Therefore, the first coil end 62a and the second coil end 62b are coil ends that protrude from the side surfaces of the stator core 61 in the axial direction X.

[0043] The first coil end 62a surrounds the bearing 14 from the outside in the radial direction Y. Specifically, the first coil end 62a surrounds the first boss portion 12c and the bearing 14 arranged on the inner peripheral surface of the first boss portion 12c from the outside in the radial direction Y. The first coil end 62a is spaced apart from the first boss portion 12c in the radial direction Y. The second coil end 62b surrounds the bearing 14 from the outside in the radial direction Y. Specifically, the second coil end 62b surrounds the second boss portion 13c and the bearing 14 arranged on the inner peripheral surface of the second boss portion 13c from the outside in the radial direction Y. The second coil end 62b is spaced apart from the second boss portion 13c in the radial direction Y.

[0044] The bearing 14 arranged on the inner peripheral surface of the first boss portion 12c is located between the first coil end 62a and the first exposed portion 42 in the radial direction Y. The bearing 14 arranged on the inner peripheral surface of the second boss portion 13c is located between the second coil end 62b and the second exposed portion 52 in the radial direction Y. Therefore, the bearing 14 is located between the shaft member 40 and the first coil end 62a and the second coil end 62b as the coil ends in the radial direction Y as the perpendicular direction. In this embodiment, the first boss portion 12c and the bearing 14 arranged on the inner peripheral surface of the first boss portion 12c are located between the first coil end 62a and the first exposed portion 42 in the radial direction Y. The bearing 14 arranged on the second boss portion 13c and the inner peripheral surface of the second boss portion 13c are located between the second coil end 62b and the second exposed portion 52 in the radial direction Y.

[0045] <Stator core dimensions> As shown in FIG. 2, the point on the orthogonal axis L2 at the center of the yoke 71 is defined as the center point P. The center point P is located on the axis L1 of the shaft member 40. The intersection of the orthogonal axis L2 and the outer peripheral surface 71a of the yoke 71 is defined as the first intersection point P1. The dimension from the center point P to the first intersection point P1 is defined as La / 2. La / 2 corresponds to the outer diameter of the stator core 61. The intersection of the orthogonal axis L2 and the end surface 76 of the tooth 72 is defined as the second intersection point P2. The dimension from the center point P to the second intersection point P2 is defined as Lb / 2. Lb / 2 corresponds to the inner diameter of the stator core 61. The thickness of the yoke 71 on the orthogonal axis L2 is defined as Lc, and the length of the tooth 72 on the orthogonal axis L2 is defined as Ld. Ld corresponds to the dimension in the radial direction Y between an extension surface V obtained by extending the inner peripheral surfaces of the yoke 71 that sandwich the teeth 72 in the circumferential direction of the yoke 71 and the end faces 76 of the teeth 72. Lc corresponds to the dimension obtained by subtracting Ld from the dimension in the radial direction Y between the outer peripheral surface 71a of the yoke 71 and the end faces 76 of the teeth 72. La / 2-Lb / 2=Lc+Ld, and 0.15≦Lb / La≦0.35. Lc / Ld≧0.35.

[0046] <Relationship between stator core dimensions, natural frequency, and OA value> As shown in Fig. 3, the inventors of the present application measured the natural frequency and OA value when the shaft member 40 was rotated at a predetermined rotation speed for each of the rotating electric machines 10 of the comparative example and the embodiment. As comparative examples, measurements were performed for the first comparative example A and the second comparative example B. As embodiments, measurements were performed for the first embodiment C, the second embodiment D, and the third embodiment E. The OA value is an overall value, and indicates the loudness of the sound generated by the rotating electric machine 10 in each example.

[0047] In the first comparative example A, the second comparative example B, the first embodiment C, the second embodiment D, and the third embodiment E, La / 2 and Lb / 2 were set so as to satisfy the relationship of 0.15≦Lb / La≦0.35. Lc and Ld were set in each example so that Lc / Ld increases in the order of the first comparative example A, the second comparative example B, the first embodiment C, the second embodiment D, and the third embodiment E.

[0048] In Fig. 3, the natural frequency is shown by an open plot, and the OA value is shown by a filled plot. The natural frequency increased from the first comparative example A to the second comparative example B, the first embodiment C, and the second embodiment D, and was slightly lower in the third embodiment E than in the second embodiment D. Therefore, as shown by the dashed line in Fig. 3, the natural frequency tends to increase as Lc / Ld increases. In contrast, the OA value decreased from the first comparative example A to the second comparative example B and the first embodiment C, increased slightly from the first embodiment C to the second embodiment D, and decreased slightly from the second embodiment D to the third embodiment E.

[0049] The relationship between the natural frequency and the OA value is usually such that the larger the natural frequency, the smaller the OA value. The behavior of the OA value estimated from the measurement results of each example shown in Fig. 3 is shown by the dashed line in Fig. 3. This behavior shows different aspects when Lc / Ld is 0.35 or more. In detail, in the range of Lc / Ld<0.35, the OA value behaves in a manner that the larger Lc / Ld is, the smaller the OA value becomes. In the range of Lc / Ld≧0.35, the OA value behaves in a manner that remains almost flat even if Lc / Ld varies.

[0050] Therefore, the above measurement results show that the rotating electric machine 10 with Lc / Ld≧0.35 generates less noise during operation than the rotating electric machine 10 with Lc / Ld<0.35. Also, it was shown that if Lc / Ld≧0.35, the above rotating electric machine 10 can achieve a noise reduction effect regardless of the magnitude of Lc / Ld.

[0051] [Operation of the embodiment] Next, the operation of this embodiment will be described. In the case of the rotating electric machine 10 in which the shaft member 40 rotates at a high speed, the dimension of the shaft member 40 in the radial direction Y may be reduced in order to suppress the loss of the rotor 19. In particular, when the rotating electric machine 10 is a speed type compressor, the rotation speed of the shaft member 40 is higher than that of a volumetric compressor, so it is preferable to reduce the dimension of the shaft member 40 in the radial direction Y as described above. In such a case, in order to ensure an appropriate value for the dimension of the gap between the shaft member 40 and the end face 76 of the tooth 72 in the radial direction Y, it is necessary to reduce Lb / 2, which is the dimension from the center point P of the yoke 71 to the second intersection point P2, in accordance with the dimension of the shaft member 40 described above. In addition, it is necessary to ensure an area occupied by the coil 62 inside the yoke 71. In detail, since the size of the slot S1 in which the coil 62 is located becomes smaller as it approaches the rotor 19, it is necessary to ensure the area occupied by the coil 62 in the slot S1 by ensuring the length of the tooth 72. Therefore, there is a limit to reducing La / 2, which is the dimension from the center point P to the first intersection point P1. As a result, the ratio of La / 2 to Lb / 2 falls within a specific range, such as 0.15≦Lb / La≦0.35. In the rotating electric machine 10 in which the ratio falls within the specific range, the thickness Lc of the yoke 71 decreases as the length Ld of the teeth 72 increases.

[0052] In the rotating electric machine 10 of this embodiment, Lc / Ld≧0.35 is satisfied as described above by increasing Lc while maintaining Ld at a size sufficient to ensure the area occupied by the coil 62 in the slot S1 as described above. This reduces the proportion of the length of the teeth 72 in the dimension of the stator core 61 in the radial direction Y compared to when Lc / Ld<0.35.

[0053] [Effects of the embodiment] Next, the effects of this embodiment will be described. (1) Lc / Ld≧0.35. Therefore, compared to when Lc / Ld<0.35, the ratio of the length of the teeth 72 to the dimension of the stator core 61 in the radial direction Y is smaller, so that the teeth 72 are less likely to vibrate when the rotating electric machine 10 is driven. Also, compared to when Lc / Ld<0.35, the natural frequency of the rotating electric machine 10 can be increased to a value outside the range of the operating frequency, so that the occurrence of resonance when the rotating electric machine 10 is driven can be suppressed. Therefore, in the case where the coil 62 is wound around the teeth 72 by concentrated winding and the rotating electric machine 10 is prone to generate noise due to vibration of the teeth 72, the noise of the rotating electric machine 10 generated due to vibration when the rotating electric machine 10 is driven can be reduced.

[0054] (2) Inside the stator core 61, slots S1 are formed, which are spaces located between the teeth 72 adjacent to each other in the circumferential direction of the yoke 71. Six slots S1 are arranged in the circumferential direction of the yoke 71. The magnetic body 30 is magnetized in the radial direction Y and has two poles. Such a stator 60 has a vibration mode in which the magnetic body 30 is deformed in a circular quadratic manner. Therefore, compared to a case in which the magnetic body 30 is deformed in a vibration mode other than a circular quadratic manner, noise generated by driving the rotating electric machine 10 tends to be large. Therefore, by reducing the noise of the rotating electric machine 10 generated due to the vibration generated by driving the rotating electric machine 10, it is possible to reduce noise even in the rotating electric machine 10, which tends to be noisy as described above.

[0055] (3) The coil 62 is wound around a portion of the tooth main body 73 that faces the yoke 71 in the radial direction Y, and is not wound around a portion of the tooth tip 74 in the radial direction Y. Therefore, compared to a case in which the coil 62 is wound around the entire tooth main body 73 in the radial direction Y, the center of gravity of the tooth 72 around which the coil 62 is wound is shifted toward the yoke 71 in the radial direction Y, and vibration of the tooth 72 caused by driving the rotating electric machine 10 is further reduced. Therefore, the noise of the rotating electric machine 10 caused by vibration caused by driving the rotating electric machine 10 can be further reduced.

[0056] (4) The coil 62 has a first coil end 62a and a second coil end 62b as coil ends. The first coil end 62a protrudes from a first side surface 61a as a side surface of the stator core 61 in the axial direction X. The second coil end 62b protrudes from a second side surface 61b as a side surface of the stator core 61 in the axial direction X. The bearing 14 is located between the shaft member 40 and the first coil end 62a and the second coil end 62b in the radial direction Y as a perpendicular direction. In such a rotating electric machine 10, the length Ld of the teeth 72 may be increased in order to provide a space for arranging the bearing 14 between the shaft member 40 and the first coil end 62a and the second coil end 62b. Even in the rotating electric machine 10 in which Ld is set large in this way, the noise of the rotating electric machine 10 caused by the vibration of the teeth 72 due to driving can be reduced.

[0057] [Example of change] The embodiment can be modified as follows: The embodiment and the following modified examples can be combined with each other to the extent that there is no technical contradiction.

[0058] The yoke 71 may have a tubular shape other than a cylindrical shape, such as a polygonal tubular shape. The number of slots S1 formed inside the stator core 61 may be less than six or may be seven or more. In this case, the number of teeth 72 included in the stator core 61 increases or decreases depending on the number of slots S1.

[0059] The magnetic body 30 may have four or more poles. The magnetic body 30 may be magnetized in a direction other than the radial direction Y. For example, the magnetic body 30 may be magnetized in the axial direction X.

[0060] The magnetic body 30 is not limited to a permanent magnet. The magnetic body 30 may be, for example, a laminated core, an amorphous core, or a powder core. The magnetic body 30 does not need to be cylindrical. For example, the magnetic body 30 may be in the shape of a square prism.

[0061] The magnetic body 30 does not necessarily have to be adjacent to the shaft member 40 in the axial direction X. For example, the magnetic body 30 may be cylindrical and extend in the axial direction X, and cover the shaft member 40 from the outside.

[0062] The first shaft member 41 may be omitted from the shaft member 40. The coil 62 may be wound around a portion of the tooth main body 73 on the tooth tip portion 74 side in the radial direction Y, and not wound around a portion on the yoke 71 side in the radial direction Y. The coil 62 may be wound around a central portion of the tooth main body 73 in the radial direction Y, and not wound around both ends in the radial direction Y. The coil 62 may be wound around the entire tooth main body 73 in the radial direction Y.

[0063] The stator core 61 is not limited to being formed by stacking a plurality of electromagnetic steel plates 63. For example, the stator core 61 may be formed from a single member. [Explanation of symbols]

[0064] L1...axis, L2...orthogonal axis, P...center point, P1...first intersection point, P2...second intersection point, S1...slot, X...axial direction, Y...radial direction as orthogonal direction, 10...rotating electric machine, 11...housing, 14...bearing, 19...rotor, 30...magnetic body, 40...shaft member, 60...stator, 61...stator core, 62...coil, 71...yoke, 71a...outer surface, 72...teeth, 73...teeth main body, 73a...first end, 73b...second end, 74...teeth tip, 76...end face.

Claims

1. a rotor having a magnetic body and a shaft member that rotates integrally with the magnetic body; A rotating electric machine including a stator having a stator core and a coil, a bearing that rotatably supports the shaft member with respect to a housing that accommodates the rotating electric machine, If a line extending in a direction perpendicular to the axis of the shaft member is defined as an orthogonal axis, the stator core includes a cylindrical yoke extending in an axial direction of the shaft member and centered on the axis, and teeth positioned inside the yoke and extending from the yoke along the orthogonal axis, The coil is wound around the teeth by concentrated winding, If the point on the orthogonal axis at the center of the yoke is the center point, the dimension from the center point to the intersection of the orthogonal axis and the outer circumferential surface of the yoke is La / 2, the dimension from the center point to the intersection of the orthogonal axis and the end faces of the teeth is Lb / 2, the thickness of the yoke on the orthogonal axis is Lc, and the length of the teeth on the orthogonal axis is Ld, then La / 2-Lb / 2=Lc+Ld, 0.15≦Lb / La≦0.35, A rotating electric machine characterized in that Lc / Ld≧0.

35.

2. A slot is formed inside the stator core, which is a space located between adjacent teeth in a circumferential direction of the yoke, Six of the slots are arranged in a circumferential direction of the yoke, The rotating electric machine according to claim 1 , wherein the magnetic body is magnetized in the orthogonal direction and has two poles.

3. The teeth each have a shaft-shaped teeth main body portion extending from the yoke in the perpendicular direction and a teeth tip portion, Of both ends of the teeth main body in the orthogonal direction, an end connected to the yoke is defined as a first end, and an end opposite to the first end is defined as a second end. The tooth tip portion extends from the second end in a circumferential direction of the yoke, 3 . The rotating electric machine according to claim 1 , wherein the coil is wound around a portion of the tooth main body that is on the yoke side in the orthogonal direction, and is not wound around a portion of the tooth tip side in the orthogonal direction.

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