CN118923021A - Stator and rotary machine - Google Patents

Abstract

The present invention aims to provide a stator having an improved tooth shape. The stator is a stator of a rotating machine arranged radially outside a rotor having an axis extending along a central axis with an air gap therebetween, wherein the stator has a stator core formed of laminated steel plates, the stator core having a plurality of teeth extending from the radial outside to the radial inside and having a radial inside end as a front end, at least one of the plurality of teeth having a base extending from the radial outside to the radial inside and a flange extending circumferentially from the base on the radial inside of the base, the flange having a groove recessed radially outward at the radial inside end, and when the rising angle of the flange is set to θ1, the rising angle of the groove is set to θ2, the width of the tooth is set to t1, the width of the flange is set to t2, and the distance between the ends of the groove is set to w, the relationship of t2>w>t1 and θ1>θ2 is satisfied.

Description

Stator and rotating machine

Technical Field

The present invention relates to a stator and a rotating machine.

Background Art

Conventionally, as a stator of a rotating machine, there is known a structure in which a plurality of teeth extending radially inward from the back of the core are provided in the stator core. Patent document 1 discloses a structure in which slots are provided at the radial inner end of the tooth facing the rotor, and the number of slots is different between adjacent teeth, for the purpose of making the noise generated when the rotating electric machine for a vehicle is operated difficult for the driver to detect.

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Publication No. 2017-118713

Summary of the invention

Problems to be solved by the invention

However, it is known that iron loss and NV performance can be improved by forming a groove at the radial inner end of the tooth as described in Patent Document 1. NV is an abbreviation of Noise Vibration, which is caused by torque pulsation, radial force, and the like.

The deeper the groove at the radial inner end of the tooth, the more 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.

The stator core is formed by stacking electromagnetic steel sheets punched into the desired shape and stacked together. However, if the rigidity is reduced, it may be deformed due to mechanical stress during punching and manufacturing. Since the shape of the radial inner end of the tooth is highly sensitive to iron loss and NV performance, even a small deformation has a large impact on the characteristics, which may lead to an increase in deviation and deterioration of process capability. Therefore, in the past, there was room for improvement in the shape of the teeth.

An object of the present invention is to provide a stator having an improved tooth shape.

Means for solving problems

A stator according to one embodiment of the present invention is a stator of a rotating machine arranged with an air gap on the radial outside of a rotor having an axis extending along a central axis, wherein the stator has a stator core formed of laminated steel plates, the stator core having a plurality of teeth extending from the radial outside to the radial inside and having a radial inner end as a front end, at least one of the plurality of teeth having a base extending from the radial outside to the radial inside and a flange portion extending circumferentially on both sides of the radial inside of the base more than the base, the flange portion having a groove portion recessed radially outward at the radial inner end, and when the rising angle of the flange portion is set to θ1, the rising angle of the groove portion is set to θ2, the width of the tooth is set to t1, the width of the flange portion is set to t2, and the distance between the ends of the groove portion is set to w, the relationship t2>w>t1 and θ1>θ2 is satisfied.

In the stator of one embodiment described above, the groove portion rises in a curved line, and the groove portion rises at an angle formed by a tangent line of a circle inscribed in the groove portion and a straight line orthogonal to a straight line passing through the circumferential center of the base portion and parallel to the radial direction, i.e., a reference line.

In the stator of one embodiment described above, the rising flange portion is a curve, and the rising angle of the flange portion is the angle formed by a tangent line of a circle inscribed in the rising flange portion and a straight line orthogonal to a straight line passing through the circumferential center of the base portion and parallel to the radial direction, i.e., a reference line.

In the stator of the above aspect, the groove portion is a first groove portion, and the flange portion has a second groove portion that is line symmetrical to the first groove portion with a reference line as a symmetry axis, wherein the reference line is a straight line passing through the circumferential center of the base portion and parallel to the radial direction.

In the stator according to the above aspect, the groove portion is a first groove portion, and the flange portion has a second groove portion that is asymmetric with the first groove portion.

In the stator of the above aspect, the groove portion is a single groove portion in which a bottom of a groove arranged on one side in the circumferential direction relative to a reference line communicates with a bottom of a groove arranged on the other side in the circumferential direction relative to the reference line.

In the stator according to the above aspect, the flange portion has a plurality of grooves recessed from the radially inner side to the radially outer side.

In the stator of one embodiment described above,

The relationship of θ2/θ1≤0.6 is satisfied.

A rotating machine according to one aspect of the present invention includes the above-mentioned stator and the above-mentioned rotor.

Effects of the Invention

According to one aspect of the present invention, it is possible to provide a stator having an improved tooth shape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a stator core according to a first embodiment of the present invention as viewed from one axial side.

FIG. 2 is a diagram showing a tooth according to the first embodiment of the present invention, and is an enlarged side view showing the tooth 122 shown in FIG. 1 .

FIG. 3 is a graph showing changes in loss when θ2 is changed under the condition of the range of θ2 / θ1 <1.

FIG. 4 is a graph showing changes in the electromagnetic force (radial force) when θ2 is changed under the condition of the range of θ2/θ1<1.

FIG. 5 is a diagram showing teeth according to a second embodiment of the present invention, and is an enlarged side view showing a tooth 1122 corresponding to the tooth 122 shown in FIG. 1 .

FIG. 6 is a diagram showing teeth according to a third embodiment of the present invention, and is an enlarged side view showing a tooth 2122 corresponding to the tooth 122 shown in FIG. 1 .

FIG. 7 is a diagram showing a tooth according to a fourth embodiment of the present invention, and is a side view showing an enlarged flange portion 3131 corresponding to the flange portion 1131 shown in FIG. 1 .

DETAILED DESCRIPTION

Hereinafter, a stator according to an embodiment of the present invention will be described with reference to the accompanying drawings. It should be noted that in the following drawings, in order to facilitate understanding of each structure, the actual structure and the scale and number of each structure may be different.

In addition, in the accompanying drawings, an XYZ coordinate system is appropriately represented as a three-dimensional orthogonal coordinate system. In the XYZ coordinate system, the Z-axis direction is a direction parallel to the axial direction of the center axis J shown in FIG. 1. The Y-axis direction is the up-down direction of FIG. 1 in the radial direction relative to the center axis J. The X-axis direction is a direction orthogonal to both the Z-axis direction and the Y-axis direction. In any one of the X-axis direction, the Y-axis direction, and the Z-axis direction, the side indicated by the arrow shown in the figure is set as the + side, and the opposite side is set as the - side.

In addition, in the following description, the positive side (+Z side) in the Z-axis direction is referred to as "one side", and the negative side (-Z side) in the Z-axis direction is referred to as "the other side". It should be noted that one side and the other side are names used for explanation only, and do not limit the actual positional relationship and direction. In addition, unless otherwise specified, the direction parallel to the center axis J (Z-axis direction) is referred to as "axial", the radial direction centered on the center axis J is referred to as "radial", and the circumferential direction centered on the center axis J, that is, the direction of the axis around the center axis J, is referred to as "circumferential". The side closer to the center axis J in the radial direction is referred to as the "radial inner side", and the side away from the center axis J is referred to as the "radial outer side". In the circumferential direction, the side indicated by the arrow shown in the figure is set as the +θ side, and the opposite side is set as the -θ side.

It should be noted that, in this specification, "extending in the axial direction" includes not only the case of extending strictly in the axial direction (Z-axis direction), but also the case of extending in a direction inclined within a range of less than 45° relative to the axial direction. In addition, in this specification, "extending in the radial direction" includes not only the case of extending strictly in the radial direction, that is, the direction perpendicular to the axial direction (Z-axis direction), but also the case of extending in a direction inclined within a range of less than 45° relative to the radial direction. In addition, "parallel" includes not only the case of being strictly parallel, but also the case of being inclined within a range of less than 45°.

<First Embodiment>

FIG. 1 is a side view of a stator core according to a first embodiment of the present invention viewed from one axial side. The stator core 100 is used for a stator of a motor. The motor is an example of a rotating machine. The motor comprises: a rotor having a shaft extending along a central axis J; a first bearing for supporting the shaft on one axial side of the rotor; a second bearing for supporting the shaft on the other axial side of the rotor; and a stator arranged radially outside the rotor with an air gap therebetween. The stator comprises a stator core 100 and a stator coil.

The stator core 100 is formed by stacking a plurality of electromagnetic steel sheets punched into the shape shown in FIG. 1 in the axial direction. The stator core 100 has a core back 110 extending radially outwardly throughout the entire circumference and a plurality of teeth 120 extending radially inwardly from the inner circumference of the core back 110. A tooth slot is formed between each of the plurality of teeth 120 and the adjacent teeth 120. The tooth slot accommodates the stator coil. The tooth 121, the tooth 122, and the tooth 123 are each one of the plurality of teeth 120.

Example 1

Fig. 2 is a diagram showing a tooth according to the first embodiment of the present invention, and is an enlarged side view showing the tooth 122 shown in Fig. 1. In the following description, the shape of the tooth 122 is described, but in the present embodiment, all of the plurality of teeth 120 have the same shape as the tooth 122. It should be noted that at least one of the plurality of teeth 120 may also have the shape of the tooth 122 described below.

The tooth 122 has a base 140 extending radially inward from the inner circumferential side of the core back 110. The tooth 122 has a flange 131 extending circumferentially to both sides relative to the base 131 on the radially inner side of the base 140. In FIG2 , a 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 the reference line K as the axis of symmetry. Since the tooth 122 is linearly symmetrical, in the following description, the shape of the tooth 122 is mainly described with respect to the portion on the -θ side relative to the reference line K.

The edge of the -θ side 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 periphery of the core back 110. The straight line 141 extends radially inward from the radially outer end. The radial inner side of the straight line 141 is closer to the reference line K than the radial outer side. The straight line connecting the -θ side edge and the +θ side edge of the radially inner 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 inner end of the base 140 (hereinafter also referred to as "tooth width") is t1.

The edge of the -θ side of the flange portion 131 is formed by the straight line 132 and the straight line 138. The radially outer end of the straight line 132 is connected to the radially inner end of the straight line 141. The straight line 132 extends radially inward from the radially outer end. The radially outer side of the straight line 132 is closer to the reference line K than the radially inner side. The angle formed by the straight line 132 and the straight line orthogonal to the reference line K (hereinafter also referred to as the "rising angle of the flange portion") is θ1.

The radially outer end of the straight line 138 is connected to the radially inner end of the straight line 132. The straight line 138 extends radially inward from the radially outer end. The straight line 138 is parallel to the reference line K.

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

The -θ side end of the straight line 133 is connected to the +θ side end of the straight line 139. The straight line 133 extends from the -θ side to the +θ side. The +θ side of the straight line 133 is closer to the core back 110 than the -θ side. The angle formed by the straight line 133 and the straight line orthogonal to the reference line K (hereinafter also referred to as "groove rise angle") is θ2.

The -θ side end of the straight line 134 is connected to the +θ side end of the straight line 133. The straight line 134 extends from the -θ side to the +θ side. The -θ side of the straight line 134 is closer to the core back 110 than the +θ side.

The -θ side end of the straight line 136 is connected to the +θ side end of the straight line 134. The straight line 136 extends from the -θ side to the +θ side. The straight line 136 is orthogonal to the reference line K.

Flange 131 has groove 135 formed by straight lines 133 and 134 and recessed radially outward from straight lines 139 and 136. Flange 131 has groove 137 corresponding to groove 135 at +θ side relative to reference line K.

The straight line connecting the -θ side end of the groove 135 and the +θ side end of the groove 137 is perpendicular to the reference line K. The length of the straight line connecting the -θ side end of the groove 135 and the +θ side end of the groove 137 (hereinafter also referred to as "the distance between the ends of the grooves") is w.

The straight line connecting the -θ side end and the +θ side end of the radial inner end of the flange portion 131 is perpendicular to the reference line K. The length of the straight line connecting the -θ side end and the +θ side end of the radial inner end of the flange portion 131 (hereinafter also referred to as "flange width") is t2.

In the present embodiment, the groove 135 is provided in such a manner that θ1>θ2, that is, in such a manner that the flange 131 becomes tapered, and the relationship among the above-mentioned t1, t2 and w is t2>w>t1. In the present embodiment, the groove 135 and the groove 137 are provided in such a manner that they are line-symmetrical with respect to the reference line K as the axis of symmetry, but a further groove may be provided between the groove 135 and the groove 137. In addition, in the present embodiment, the groove 135 and the groove 137 are line-symmetrical with respect to the reference line K as the axis of symmetry, but as long as θ1>θ2, an asymmetrical shape may be adopted. In addition, the groove 135 and the groove 137 are not limited to being composed of two straight lines, but may be formed by curved lines such as a circle, an arc shape, an ellipse, or may be formed by three or more straight lines.

According to the present embodiment, sufficient rigidity against deformation can be ensured by making θ1>θ2 and enlarging the base of the flange portion 131. This structure can reduce iron loss and NV performance compared to a case without a groove.

The deeper the groove 135 is, the more the iron loss and NV performance tend to be improved, but the deeper the groove 135 is, the wider the effective gap length is, so the torque is reduced. That is, when the same torque is generated, the current needs to be increased, and the copper loss is deteriorated. Therefore, when considering not only the NV performance but also the motor efficiency, it is preferable to strike a balance between the two to determine the depth of the groove 135.

FIG3 is a graph showing the change in loss when θ2 is changed under the condition of θ2/θ1<1. In FIG3, the horizontal axis is θ2/θ1 and the vertical axis is the loss. FIG4 is a graph showing the change in electromagnetic force (radial force) when θ2 is changed under the condition of θ2/θ1<1. In FIG4, the horizontal axis is θ2/θ1 and the vertical axis is the radial force. In FIG3 and FIG4, the change in loss and radial force when θ2/θ1=0, i.e., when there is no groove 135, is normalized to 1.

Referring to FIG. 3 , it can be seen that the larger θ2/θ1 is (the deeper the groove 135 is), the more the stator iron loss is improved, but due to the reduction in torque, the copper loss is deteriorated, so the loss of the motor (copper loss + iron loss) changes little. When the iron loss is separated into stator iron loss and rotor iron loss, in the range of θ2/θ1≤0.6, it can be confirmed that the rotor iron loss is improved compared to the case without the groove 135. Since the rotor as a rotating body is difficult to cool, the improvement of the rotor loss is thermally beneficial. Regarding the radial force, in the range of θ2/θ1<1, it can be confirmed that the deeper the groove 135 is, the more the radial force is improved. Therefore, by setting θ1>θ2, it is possible to ensure rigidity and improve NV performance. More preferably, by setting θ2/θ1≤0.6, it is possible to take into account both the improvement of NV performance and the improvement of efficiency and thermal performance.

Example 2

FIG. 5 is a diagram showing teeth according to a second embodiment of the present invention, and is an enlarged side view showing a tooth 1122 corresponding to the tooth 122 shown in FIG. 1 .

The base 1140 is equivalent to the base 140 of FIG. 2. The flange 1131 is equivalent to the flange 131 of FIG. 2. The straight line 1141 is equivalent to the straight line 141 of FIG. 2. The straight line 1132 is equivalent to the straight line 132 of FIG. 2. The straight line 1138 is equivalent to the straight line 138 of FIG. 2. The straight line 1139 is equivalent to the straight line 139 of FIG. 2. The straight line 1133 is equivalent to the straight line 133 of FIG. 2. The straight line 1134 is equivalent to the straight line 134 of FIG. 2. The groove 1135 is equivalent to the groove 135 of FIG. 2. The groove 1137 is equivalent to the groove 137 of FIG. 2.

In Example 2, the flange portion 1131 has a groove portion 1136 between the groove portion 1135 and the groove portion 1137. In Example 2, by setting θ1>θ2, it is possible to ensure rigidity and improve NV performance. More preferably, by setting θ2/θ1≤0.6, it is possible to achieve both improvement in NV performance and improvement in efficiency and thermal performance.

Example 3

FIG. 6 is a diagram showing teeth according to a third embodiment of the present invention, and is an enlarged side view showing a tooth 2122 corresponding to the tooth 122 shown in FIG. 1 .

The base 2140 corresponds to the base 140 of Fig. 2. The flange 2131 corresponds to the flange 131 of Fig. 2. The straight line 2141 corresponds to the straight line 141 of Fig. 2. The straight line 2132 corresponds to the straight line 132 of Fig. 2. The straight line 2138 corresponds to the straight line 138 of Fig. 2. The straight line 2139 corresponds to the straight line 139 of Fig. 2. The straight line 2133 corresponds to the straight line 133 of Fig. 2.

The -θ side end of the straight line 2134 is connected to the +θ side end of the straight line 2133. The straight line 2134 extends from the -θ side to the +θ side. The straight line 2134 is orthogonal to the reference line K. The groove portion 2135 of this embodiment is a shape in which the groove portion 135 and the groove portion 137 of Figure 2 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) that is connected to the bottom of the groove (equivalent to the groove portion 135) arranged on the -θ side (one side of the circumferential direction) of the reference line and the bottom of the groove (equivalent to the groove portion 137) arranged on the +θ side (the other side of the circumferential direction) 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 Example 2, by setting θ1>θ2, it is possible to ensure rigidity and improve NV performance. More preferably, by setting θ2/θ1≤0.6, it is possible to achieve both improvement in NV performance and improvement in efficiency and thermal performance.

Example 4

FIG7 is a diagram showing a tooth of Example 4 of the present invention, and is an enlarged side view showing a flange portion 3131 corresponding to the flange portion 1131 shown in FIG2. In FIG2, the groove portion 135 is formed by two straight lines, the straight line 133 and the straight line 134, but the present invention is not limited thereto, and a groove portion formed by a curved line like the groove portion 3135 shown in FIG7 can also be applied. In this case, the angle formed by the tangent line of the circle 3135a inscribed in the -θ side end of the groove portion 3135 (the rise of the groove portion 3135) and the straight line 3136 (the straight line orthogonal to the reference line K) at the radial inner end of the flange portion 1131 is set to θ2, and the above-mentioned relationship between θ1 and θ2 can be applied.

In addition, when the straight line 132 in FIG. 2 is a curve, for example, when the flange portion 131 is formed by a curve bulging toward the -θ side end instead of the straight line 132, the present invention can also be applied. In this case, the angle formed by the tangent line of the circle inscribed in the -θ side end of the curve (the rise of the groove portion) and the straight line orthogonal to the reference line K is set to θ1, and the above-mentioned relationship between θ1 and θ2 can be applied.

In addition, when the straight lines 132 and 138 in FIG. 2 are curved lines, for example, when the flange portion 131 is formed by a curved line that bulges toward the -θ side end instead of the straight lines 132 and 138, the present invention can also be applied. In this case, the angle formed by the tangent line of the circle inscribed in the -θ side end of the curved line (the rise of the groove portion) and the straight line orthogonal to the reference line K is θ1, and the above-mentioned relationship between θ1 and θ2 can be applied.

The present invention is not limited to the above-mentioned embodiments, and various improvements and design changes may be made without departing from the scope of the present invention. In addition, the embodiments disclosed this time should be considered to be illustrative rather than restrictive in all aspects. The scope of the present invention is not shown by the above description but by the claims, and is intended to include all changes within the meaning and scope equivalent to the claims.

This application claims the priority of Japanese patent application No. 2022-74484 filed on April 28, 2022, and cites all the contents described in the Japanese patent application.

Description of Reference Numerals

100 stator core, 110 core back, 120 teeth

Claims (9)

1. A stator of a rotating machine arranged radially outside a rotor having a shaft extending along a central axis with an air gap therebetween, wherein: The stator has a stator core composed of laminated steel plates. The stator core has a plurality of teeth extending from the radial outer side to the radial inner side and having the radial inner side end as the front end. At least one of the plurality of teeth has a base portion extending from the radial outer side to the radial inner side and a flange portion extending circumferentially from the base portion on the radial inner side of the base portion. The flange portion has a groove portion recessed toward the radially outer side at the radially inner end. When the rising angle of the flange is θ1, the rising angle of the groove is θ2, the width of the tooth is t1, the width of the flange is t2, and the distance between the ends of the groove is w, The relationship t2>w>t1 and θ1>θ2 is satisfied. 2. The stator according to claim 1, wherein: The groove portion is formed in a curved line. The rising angle of the groove portion is an angle formed by a tangent line of a circle inscribed in the rising groove portion and a straight line perpendicular to a reference line which passes through the circumferential center of the base portion and is parallel to the radial direction. 3. The stator according to claim 1, wherein: The flange portion is raised in a curved line. The rising angle of the flange portion is an angle formed by a tangent line of a circle inscribed in the rising of the flange portion and a straight line perpendicular to a reference line which passes through the circumferential center of the base portion and is parallel to the radial direction. 4. The stator according to claim 1, wherein: The groove portion is a first groove portion, The flange portion has a second groove portion that is line-symmetrical to the first groove portion with a reference line as a symmetry axis, wherein the reference line is a straight line that passes through the circumferential center of the base portion and is parallel to the radial direction. 5. The stator according to claim 1, wherein: The groove portion is a first groove portion, The flange portion has a second groove portion that is asymmetrical with the first groove portion. 6. The stator according to claim 1, wherein: The groove portion is a groove portion in which the bottom of a groove arranged on one side of the reference line in the circumferential direction communicates with the bottom of a groove arranged on the other side of the reference line in the circumferential direction. 7. The stator according to claim 1, wherein: The flange portion has a plurality of grooves recessed from the radial inner side to the radial outer side. 8. The stator according to claim 1, wherein: The relationship of θ2/θ1≤0.6 is satisfied. 9. A rotating machine, wherein the rotating machine comprises: The stator according to any one of claims 1 to 6; and The rotor.