Stator and rotating machine

Abstract

The object of the present invention is to provide a stator with improved tooth shape. The stator is the stator of a rotating machine arranged radially outside a rotor having an axis extending along a central axis, separated by an air gap. The stator has a stator core made of laminated steel plates, the stator core having a plurality of teeth extending radially outward and radially inward with the radially inward end as the leading edge. At least one of the plurality of teeth has a base extending radially outward and a flange portion extending circumferentially to both sides of the base radially inward. The flange portion has a groove recessed radially outward at its radially inward end. When the angle of the flange portion is set to θ1, the angle of the groove portion to θ2, the width of the tooth to t1, the width of the flange portion to t2, and the distance between the ends of the groove portions to each other is set to w, the relationships t2>w>t1 and θ1>θ2 are satisfied.

Description

Technical Field

[0001] This invention relates to stators and rotating machines. Background Technology

[0002] Conventionally, as a stator of a rotating machine, it is known to have a structure in which multiple teeth extend radially inward from the back of the stator core. In Patent Document 1, in order to make the noise generated when the rotating motor for a vehicle is not easily perceived by the driver, a structure is disclosed in which slots are provided on the radially inner end of the teeth facing the rotor, and the number of slots is different between adjacent teeth.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-118713 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, it is known, as described in Patent Document 1, that iron loss and NV performance can be improved by forming a groove at the radially inner end of the tooth. NV is short for Noise Vibration, which is caused by torque pulsation, radial force, etc.

[0008] The deeper the groove on the radial inner end of the tooth, the better the torque pulsation and radial force that affect NV performance are improved. However, if the groove is too deep, for example, the distance from the circumferential end of the tooth to the groove becomes shorter, and the rigidity and strength may be reduced.

[0009] The stator core is formed by stacking layers of electromagnet steel sheets, which are punched into the desired shape. However, if rigidity is reduced, deformation may occur due to mechanical stress during punching and manufacturing. Since the shape of the radially inner ends of the teeth is highly sensitive to iron loss and NV performance, even minute deformations can significantly impact characteristics, potentially leading to increased deviations and deterioration of process capability. Therefore, there has historically been room for improvement in the shape of the teeth.

[0010] The purpose of this invention is to provide a stator with an improved tooth shape.

[0011] Methods for solving problems

[0012] One aspect of the present invention is a stator of a rotating machine arranged radially outside a rotor having an air gap along a central axis, wherein the stator has a stator core made of laminated steel plates, the stator core having a plurality of teeth extending radially outward and radially inward with the radially inward end as the front end, at least one of the plurality of teeth having a base extending radially outward and radially inward and a flange portion extending circumferentially to both sides of the base on the radially inward side of the base, the flange portion having a groove recessed radially outward at the radially inward end, wherein when the erection angle of the flange portion is set as θ1, the erection angle of the groove portion is set as θ2, the width of the tooth is set as t1, the width of the flange portion is set as t2, and the distance between the ends of the groove portions is set as w, the relationships t2>w>t1 and θ1>θ2 are satisfied.

[0013] In one of the stators described above, the rise of the slot is a curve, and the rise angle of the slot is the angle formed by the tangent to the circle inscribed in the rise of the slot and the straight line orthogonal to the reference line that passes through the circumferential center of the base and is parallel to the radial direction.

[0014] In one of the stators described above, the flange is curved, and the angle of the flange is the angle formed by the tangent to the circle inscribed in the flange and the straight line that passes through the circumferential center of the base and is parallel to the radial direction, i.e., the reference line.

[0015] In one of the above-mentioned stators, the slot is a first slot, and the flange has a second slot that is symmetrical about the first slot with respect to a reference line as the axis of symmetry. The reference line is a straight line that passes through the circumferential center of the base and is parallel to the radial direction.

[0016] In one of the above-mentioned stators, the groove is a first groove, and the flange has a second groove that is asymmetrical with respect to the first groove.

[0017] In one of the above-mentioned stators, the slot is a slot whose bottom is connected to the bottom of a slot located on the circumferential side of the reference line and the bottom of a slot located on the other circumferential side of the reference line.

[0018] In one of the above-mentioned stators, the flange portion has a plurality of grooves recessed from the radially inner side to the radially outer side.

[0019] In the stator of one of the above methods,

[0020] The relationship θ2 / θ1 ≤ 0.6 is satisfied.

[0021] One aspect of the rotating machine of the present invention has the stator and the rotor described above.

[0022] The effects of the invention

[0023] According to one aspect of the present invention, it is possible to provide a stator with an improved tooth shape. Attached Figure Description

[0024] Figure 1 This is a side view of the stator core of the first embodiment of the present invention, viewed from the axial side.

[0025] Figure 2 This is a diagram showing the teeth of Embodiment 1 of the present invention, and is an enlarged view. Figure 1 The side view of tooth 122 shown.

[0026] Figure 3 This is a graph showing the change in loss when θ2 is changed within the range θ2 / θ1<1.

[0027] Figure 4 It is a graph showing the change of electromagnetic force (radial force) when θ2 is changed under the condition that θ2 / θ1<1.

[0028] Figure 5 This is a diagram showing the teeth of Embodiment 2 of the present invention, and is an enlarged representation. Figure 1 The side view of tooth 1122, which corresponds to tooth 122 shown.

[0029] Figure 6 This is a diagram showing the teeth of Embodiment 3 of the present invention, and is an enlarged representation. Figure 1 The side view of tooth 2122 corresponding to tooth 122 shown.

[0030] Figure 7 This is a diagram showing the teeth of Embodiment 4 of the present invention, and is an enlarged representation. Figure 1 The side view of the flange portion 3131 corresponding to the flange portion 1131 shown. Detailed Implementation

[0031] Hereinafter, the stator of an embodiment of the present invention will be described with reference to the accompanying drawings. It should be noted that, in the following drawings, for ease of understanding of each structure, the actual structure and the scale and quantity in each structure may sometimes differ.

[0032] Furthermore, in the accompanying diagram, the XYZ coordinate system is appropriately represented as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z-axis direction is perpendicular to the x-axis. Figure 1 The direction parallel to the axial direction of the central axis J is shown. The Y-axis direction is radially relative to the central axis J. Figure 1 The X-axis is the vertical direction. The X-axis is orthogonal to both the Z-axis and Y-axis. In any of the X-axis, Y-axis, and Z-axis directions, the side indicated by the arrow in the diagram is designated as the "+" side, and the opposite side is designated as the "-" side.

[0033] In the following explanation, the positive side (+Z side) in the Z-axis direction will be referred to as "one side," and the negative side (-Z side) in the Z-axis direction will be referred to as "the other side." It should be noted that "one side" and "the other side" are merely names used for illustrative purposes and do not limit the actual positional relationship or direction. Furthermore, unless otherwise specified, the direction parallel to the central axis J (Z-axis direction) will be simply referred to as "axial direction," the radial direction centered on the central axis J will be simply referred to as "radial direction," and the circumferential direction centered on the central axis J, i.e., the direction around the central axis J, will be simply referred to as "circumferential direction." The side radially closer to the central axis J will be called the "radial inner side," and the side farther from the central axis J will be called the "radial outer side." In the circumferential direction, the side indicated by the arrow in the diagram will be designated as the +θ side, and the opposite side will be designated as the -θ side.

[0034] It should be noted that, in this specification, "extending axially" includes not only the case of extending strictly along the axial direction (Z-axis direction), but also the case of extending in a direction inclined relative to the axial direction within a range of less than 45°. Furthermore, in this specification, "extending radially" includes not only the case of extending strictly in the radial direction, i.e., perpendicular to the axial direction (Z-axis direction), but also the case of extending in a direction inclined relative to the radial direction within a range of less than 45°. Additionally, "parallel" includes not only the case of being strictly parallel, but also the case of the angle between them being inclined within a range of less than 45°.

[0035] <First Implementation Method>

[0036] Figure 1 This is a side view of the stator core of the first embodiment of the present invention, viewed from the axial side. The stator core 100 is used as the stator of an electric motor. The electric motor is an example of a rotating machine. The electric motor includes: a rotor having a shaft extending along a central axis J; a first bearing supporting the shaft on the axial side of the rotor; a second bearing supporting the shaft on the axial side of the rotor; and a stator disposed radially outside the rotor with an air gap between them. The stator has a stator core 100 and stator coils.

[0037] The stator core 100 is made by stamping. Figure 1 The shape shown is formed by stacking multiple electromagnetic steel plates axially. The stator core 100 has a core back 110 extending radially outward throughout the entire circumference and multiple teeth 120 extending radially inward from the inner circumference of the core back 110. A slot is formed between each of the multiple teeth 120 and an adjacent tooth 120. The slot houses the stator coil. Teeth 121, 122, and 123 are each one of the multiple teeth 120.

[0038] Example 1

[0039] Figure 2This is a diagram showing the teeth of Embodiment 1 of the present invention, and is an enlarged view. Figure 1 The image shows a side view of tooth 122. The shape of tooth 122 will be described in the following description, but in this embodiment, all of the plurality of teeth 120 have the same shape as tooth 122. It should be noted that at least one of the plurality of teeth 120 may also have the shape of tooth 122 as described below.

[0040] The tooth 122 has a base 140 extending radially inward from the inner circumferential side of the back side 110 of the iron core. The tooth 122 has a flange 131 on the radially inward side of the base 140 that extends circumferentially to both sides compared to the base 131. Figure 2 In the diagram, the reference line K is a straight line passing through the circumferential center of the base 140 and parallel to the radial direction. The tooth 122 has a linearly symmetrical shape with reference line K as the axis of symmetry. Since the tooth 122 is linearly symmetrical, the following description of the shape of the tooth 122 will mainly focus on the portion near the -θ side of reference line K.

[0041] The -θ side edge of the base 140 is formed by a straight line 141. The radially outer end of the straight line 141 is connected to the inner circumference of the back of the core 110. The straight line 141 extends radially inward from the radially outer end. The radially inward side of the straight line 141 is closer to the reference line K than the radially outer side. The straight line connecting the -θ side edge and the +θ side edge of the radially inward end of the base 140 is orthogonal to the reference line K. The length of the straight line connecting the -θ side edge and the +θ side edge of the radially inward end of the base 140 (hereinafter also referred to as the "tooth width") is t1.

[0042] The edge on the -θ side of the flange 131 is formed by straight lines 132 and 138. The radially outer end of straight line 132 is connected to the radially inner end of straight line 141. Straight line 132 extends radially inward from its radially outer end. The radially outer end of straight line 132 is closer to the reference line K than its radially inner end. The angle between straight line 132 and the straight line orthogonal to the reference line K (hereinafter also referred to as the "flange elevation angle") is θ1.

[0043] The outer radial end of line 138 connects to the inner radial end of line 132. Line 138 extends from the outer radial end towards the inner radial end. Line 138 is parallel to the baseline K.

[0044] The radially inner edge of the flange 131 is formed by straight lines 139, 133, 134, and 136. The -θ end of straight line 139 is connected to the radially inner end of straight line 138. Straight line 139 extends from the -θ side to the +θ side. Straight line 139 is parallel to the reference line K.

[0045] The -θ side of line 133 is connected to the +θ side of line 139. Line 133 extends from the -θ side to the +θ side. The +θ side of line 133 is closer to the back of the core 110 than the -θ side. The angle between line 133 and the line orthogonal to the baseline K (hereinafter also referred to as the "groove elevation angle") is θ2.

[0046] The -θ side of line 134 is connected to the +θ side of line 133. Line 134 extends from the -θ side to the +θ side. The -θ side of line 134 is closer to the back of the core 110 than the +θ side.

[0047] The -θ end of line 136 connects to the +θ end of line 134. Line 136 extends from the -θ end to the +θ end. Line 136 is orthogonal to the baseline K.

[0048] The flange portion 131 has a groove 135 formed by straight lines 133 and 134 and recessed radially outward from the radial positions of straight lines 139 and 136. The flange portion 131 has a groove 137 corresponding to the groove 135 at a position +θ closer to the reference line K.

[0049] The straight line connecting the -θ end of groove 135 and the +θ end of groove 137 is orthogonal to the baseline K. The length of the straight line connecting the -θ end of groove 135 and the +θ end of groove 137 (hereinafter also referred to as "the distance between the ends of the grooves") is w.

[0050] The straight line connecting the -θ and +θ ends of the radially inner end of the flange 131 is orthogonal to the reference line K. The length of the straight line connecting the -θ and +θ ends of the radially inner end of the flange 131 (hereinafter also referred to as the "width of the flange") is t2.

[0051] In this embodiment, the groove 135 is provided such that θ1>θ2, that is, the flange 131 becomes tapered, and the relationship between t1, t2, and w is t2>w>t1. In this embodiment, the groove 135 and the groove 137 are provided in a linearly symmetrical manner with reference line K as the axis of symmetry, but a groove may also be provided between the groove 135 and the groove 137. In addition, in this embodiment, the groove is linearly symmetrical with reference line K as the axis of symmetry, but as long as θ1>θ2, it can also be an asymmetrical shape. Furthermore, the groove 135 and the groove 137 are not limited to being composed of two straight lines, but can also be formed by curves such as circles, arcs, and ellipses, and can also be formed by three or more straight lines.

[0052] According to this embodiment, by widening the root of the flange portion 131 to make θ1 > θ2, sufficient rigidity relative to deformation can be ensured. With this structure, iron loss and NV performance can be reduced compared to the case without the groove.

[0053] A deeper slot 135 tends to improve iron loss and NV performance, but a deeper slot also results in a wider effective clearance length, thus reducing torque. In other words, to produce the same torque, a higher current is required, leading to worsened copper losses. Therefore, considering both NV performance and motor efficiency, a balance should be struck when determining the depth of the slot 135.

[0054] Figure 3 This is a graph showing the change in loss when θ2 is changed within the range θ2 / θ1<1. Figure 3 In the diagram, the horizontal axis represents θ2 / θ1, and the vertical axis represents the loss. Figure 4 This is a graph showing the change in electromagnetic force (radial force) when θ2 is changed within the range θ2 / θ1<1. Figure 4 In the diagram, the horizontal axis represents θ2 / θ1, and the vertical axis represents the radial force. Figure 3 as well as Figure 4 In this case, the loss and the change in radial force when θ2 / θ1=0, i.e. without the groove 135, are normalized to 1.

[0055] Reference Figure 3 It is known that the larger θ2 / θ1 is (the deeper the slot 135), the better the stator iron loss is improved. However, due to the decrease in torque, the copper loss deteriorates, so the change in the total motor loss (copper loss + iron loss) is small. When separating the iron loss into stator iron loss and rotor iron loss, it can be confirmed that the rotor iron loss is improved compared to the case without slot 135 within the range of θ2 / θ1≤0.6. Since the rotor, as a rotating body, is difficult to cool, the improvement in rotor loss is thermally beneficial. Regarding radial force, it can be confirmed that the deeper the slot 135 is within the range of θ2 / θ1<1, the better the radial force is improved. Therefore, by setting θ1>θ2, rigidity can be ensured and NV performance can be improved. More preferably, by setting θ2 / θ1≤0.6, improvements in NV performance, efficiency, and thermal performance can be balanced.

[0056] Example 2

[0057] Figure 5 This is a diagram showing the teeth of Embodiment 2 of the present invention, and is an enlarged representation. Figure 1 The side view of tooth 1122, which corresponds to tooth 122 shown.

[0058] Base 1140 is equivalent to Figure 2 The base 140. The flange 1131 is equivalent to Figure 2 The flange portion 131. The straight line 1141 is equivalent to... Figure 2 Line 141. Line 1132 is equivalent to... Figure 2 Line 132. Line 1138 is equivalent to... Figure 2Line 138. Line 1139 is equivalent to... Figure 2 Line 139. Line 1133 is equivalent to... Figure 2 Line 133. Line 1134 is equivalent to... Figure 2 The straight line 134. The groove 1135 is equivalent to... Figure 2 The groove 135. The groove 1137 is equivalent to Figure 2 The groove 137.

[0059] In Embodiment 2, the flange portion 1131 has a groove 1136 between the groove portion 1135 and the groove portion 1137. In Embodiment 2, by setting θ1>θ2, rigidity can be ensured and NV performance can be improved. More preferably, by setting θ2 / θ1≤0.6, both the improvement of NV performance and the improvement of efficiency and thermal performance can be taken into account.

[0060] Example 3

[0061] Figure 6 This is a diagram showing the teeth of Embodiment 3 of the present invention, and is an enlarged representation. Figure 1 The side view of tooth 2122 corresponding to tooth 122 shown.

[0062] Base 2140 is equivalent to Figure 2 The base 140. The flange 2131 is equivalent to Figure 2 The flange portion 131. The straight line 2141 is equivalent to... Figure 2 Line 141. Line 2132 is equivalent to... Figure 2 Line 132. Line 2138 is equivalent to... Figure 2 Line 138. Line 2139 is equivalent to... Figure 2 Line 139. Line 2133 is equivalent to... Figure 2 The straight line is 133.

[0063] The -θ side of line 2134 is connected to the +θ side of line 2133. Line 2134 extends from the -θ side to the +θ side. Line 2134 is orthogonal to the baseline K. In this embodiment, the groove 2135 becomes... Figure 2 The groove portions 135 and 137 are connected to each other at the bottom of the groove. That is, in this embodiment, the flange portion 2131 has a groove portion (groove portion 2135) connected to the bottom of a groove (corresponding to groove portion 135) disposed on the -θ side (circumferential side) of the reference line and a groove portion (corresponding to groove portion 137) disposed on the +θ side (circumferential side) of the reference line. In addition, in this embodiment, the flange portion 2131 has a groove portion 2136 that is recessed radially outward from the straight line 2134. In Embodiment 2, by setting θ1>θ2, rigidity can be ensured and NV performance can be improved. More preferably, by setting θ2 / θ1≤0.6, both improved NV performance and improved efficiency and thermal performance can be achieved.

[0064] Example 4

[0065] Figure 7 This is a diagram showing the teeth of Embodiment 4 of the present invention, and is an enlarged representation. Figure 2 The shown flange 1131 is a side view of the corresponding flange 3131. Figure 2 In the middle, the groove 135 is formed by two straight lines 133 and 134, but the present invention is not limited to this and can also be applied to, for example Figure 7 The groove 3135 shown is formed by a curve. In this case, the angle between the tangent of the circle 3135a inscribed in the -θ side end (the upright part of the groove 3135) and the straight line 3136 (a straight line orthogonal to the reference line K) at the radial inner end of the flange 1131 is set as θ2, and the relationship between θ1 and θ2 described above can be applied.

[0066] In addition, Figure 2 When the straight line 132 is a curve, for example, when the flange portion 131 is formed by a curve bulging towards the -θ side instead of the straight line 132, the present invention can also be applied. In this case, the angle formed by the tangent of the circle inscribed in the -θ side of the curve (the vertical part of the groove) and the straight line orthogonal to the reference line K is set as θ1, and the relationship between θ1 and θ2 described above can be applied.

[0067] In addition, Figure 2 When the straight lines 132 and 138 are curves, for example, when the flange 131 is formed by a curve bulging towards the -θ side instead of the straight lines 132 and 138, the present invention can also be applied. In this case, the angle between the tangent of the circle inscribed in the -θ side of the curve (the vertical part of the groove) and the straight line orthogonal to the reference line K is set as θ1, and the relationship between θ1 and θ2 described above can be applied.

[0068] This invention is not limited to the embodiments described above, and various modifications and design changes can be made without departing from the spirit of the invention. Furthermore, the embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. The scope of this invention is defined not by the foregoing description but by the claims, and is intended to include all modifications equivalent to and within the scope of the claims.

[0069] This application claims priority to Japanese Patent Application No. 2022-74484, filed on April 28, 2022, and incorporates all the contents of that Japanese Patent Application.

[0070] Explanation of reference numerals in the attached figures

[0071] 100 stator core, 110 core back, 120 teeth

Claims

1. A stator of a rotary machine in which a stator is disposed with an air gap on the radially outer side of a rotor having a shaft extending along a central axis, wherein the stator has a stator core composed of laminated steel sheets, the stator core has a plurality of teeth extending from the radially outer side to the radially inner side with the radially inner side end as the front end, at least one of the plurality of teeth has a base portion extending from the radially outer side to the radially inner side and a flange portion extending to both sides in the circumferential direction more than the base portion on the radially inner side of the base portion, the flange portion has a groove portion recessed to the radially outer side at the radially inner side end, when the angle of rise of the flange portion is θ1, the angle of rise of the groove portion is θ2, the width of the tooth is t1, the width of the flange portion is t2, and the distance of the end portions of the groove portion from each other is w, the relationship t2 > w > t1 and θ1 > θ2 is satisfied, the rise of the groove portion is a curve, the angle of rise of the groove portion is the angle formed by the tangent of a circle inscribed in the rise of the groove portion and a straight line orthogonal to a reference line that is a straight line passing through the circumferential center of the base portion and parallel to the radial direction, and the groove portion is formed by a curve.

2. The stator according to claim 1, wherein the rise of the flange portion is a curve, and the angle of rise of the flange portion is the angle formed by the tangent of a circle inscribed in the rise of the flange portion and a straight line orthogonal to a reference line that is a straight line passing through the circumferential center of the base portion and parallel to the radial direction.

3. The stator according to claim 1, wherein the groove portion is one groove portion that is communicated with the bottom of the groove disposed on one side in the circumferential direction from the reference line and the bottom of the groove disposed on the other side in the circumferential direction from the reference line. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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