Stator and rotating electric machine

Abstract

The present invention provides a stator and a rotating electric machine that can reduce the effects of welding on a laminated iron core that is integrated by welding and also has a cooling function. [Solution] According to the embodiment, the stator 30 comprises a stator core 110 having a plurality of laminated electromagnetic steel sheets 101, a cylindrical outer surface 118 formed to protrude from the outer surface 118 and having a plurality of protrusions 114 extending in the lamination direction, a connecting plate 120 that connects the plurality of electromagnetic steel sheets 101 and connects the circumferentially adjacent protrusions 114 to each other, forming a coolant flow path 122 between itself and the stator core 110 that extends in the lamination direction, and a stator winding wound around the stator core 110.

Description

Technical Field

[0001] The present invention relates to a stator and a rotating electrical machine.

Background Art

[0002] In a rotating electrical machine, usually, a laminated core in which a large number of punched electromagnetic steel sheets are laminated and joined is used. For example, in a frameless structure rotating electrical machine without a frame, the stator is composed of a core made of laminated electromagnetic steel sheets, core retainers arranged at two locations on both axial sides of the core so as to sandwich the core from the outside in the axial direction, and a connecting plate which is a member connecting between the two core retainers.

[0003] FIG. 10 is a cross-sectional view showing a conventional example of the configuration of the stator 200. The stator 200 has a stator core 201 made of electromagnetic steel sheets, a connecting plate 202 that connects and integrates the electromagnetic steel sheets, and a stator winding (not shown) that penetrates through the stator slots 206 formed by the stator teeth 205 and is wound around the stator core 201.

[0004] The connecting plate 202 is provided at a plurality of locations on the outer peripheral portion of the cylindrical stator core 201. The connecting plate 202 is joined to the stator core 201 and a core retainer (not shown) by welding, and serves to make the stator core 201 and the two core retainers an integral structure, and at the same time forms a ventilation path 203 for cooling. In recent years, in order to integrate the laminated structure of the electromagnetic steel sheets as the stator core, a method using caulking instead of welding has also been put into practical use. However, when used in a rotating electrical machine that requires strength such as a rotating electrical machine for a vehicle, it is generally integrated by welding.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] In the method of integrating the stator core 201 by welding the connecting plate 202 and the laminated structure of the electromagnetic steel sheet at the weld joint 204, a heat-affected zone 201w is formed in the yoke portion 201a of the stator core 201.

[0007] Here, the yoke portion 201a is a cylindrical region formed by the circumscribing cylinder 201c, which is the base of the stator teeth 205 formed on the inner circumference side of the stator core 201, i.e., the radially outer side of the stator slot 206, and the outer circumscribing surface 201s of the stator core 201. This yoke portion 201a is the main magnetic path portion in the stator core 201.

[0008] In the stator core 201, the heat-affected zone 201w, which is adjacent to the welded section 204 and is affected by the heat of welding, presents a problem in that it can cause short circuits between the laminated electrical steel sheets and deterioration of the magnetic properties of the electrical steel sheets, leading to increased iron loss.

[0009] In order to miniaturize and lighten rotating electric machines, a reduction in core back dimensions is also required, which means that the welding points and magnetic paths will be closer together, and the effects of welding will become greater.

[0010] The problem that this invention aims to solve is to provide a stator and a rotating electric machine that can reduce the effects of welding on a laminated iron core that is integrated by welding and also has a cooling function. [Means for solving the problem]

[0011] To achieve the above-mentioned objectives, the stator according to the present invention is characterized by comprising: a stator core having a plurality of laminated electromagnetic steel sheets, the outer surface of which is cylindrical and formed to protrude from the outer surface and having a plurality of protrusions extending in the lamination direction; a connecting plate that connects the plurality of electromagnetic steel sheets and connects the protrusions adjacent to each other in the circumferential direction, and forms a coolant flow path between itself and the stator core extending in the lamination direction; and a stator winding wound around the stator core. [Brief explanation of the drawing]

[0012] [Figure 1] This is a side view showing the configuration of a rotating electric machine according to the first embodiment. [Figure 2] This is a cross-sectional view showing the configuration of the stator core of a stator according to the first embodiment. [Figure 3] This is a partial cross-sectional view illustrating the protruding portion of the stator core and the connecting plate in the stator according to the first embodiment. [Figure 4] This is a partial cross-sectional view illustrating a modified example of the protruding portion of the stator core and the connecting plate in the stator according to the first embodiment. [Figure 5] This is a partial cross-sectional view illustrating the requirements for the protrusions of the stator core in a stator according to the first embodiment. [Figure 6] This is a cross-sectional view showing the configuration of a stator in a first modified example of the stator according to the first embodiment. [Figure 7] This is a cross-sectional view showing the configuration of a stator in a second modified example of the stator according to the first embodiment. [Figure 8] This is a cross-sectional view showing the configuration of a stator according to the second embodiment. [Figure 9] This is a cross-sectional view showing a modified configuration of the stator according to the second embodiment. [Figure 10] This is a cross-sectional view showing a conventional example of a stator configuration. [Modes for carrying out the invention]

[0013] Hereinafter, a stator and a rotating electric machine according to embodiments of the present invention will be described with reference to the drawings. Here, parts that are the same or similar to each other are denoted by the same reference numeral, and their overlapping descriptions are omitted.

[0014] [First Embodiment] Figure 1 is a side view showing the configuration of the rotating electric machine 1 according to the first embodiment.

[0015] The rotating electrical machine 1 has a rotor 10, a stator 30, bearings 21, a bearing bracket 22, and a frame 23. Note that it may be a frameless rotating electrical machine without the frame 23.

[0016] The rotor 10 has a rotor shaft 11 extending in the direction of the rotation axis CL, a rotor core 12 attached to the outer side in the radial direction of the rotor shaft 11, and permanent magnets 13 arranged in the rotor core 12. Note that, regarding the rotor 10, in FIG. 1, a permanent magnet type synchronous machine is illustrated, but it may be a wound type or an induction type rotor.

[0017] Hereinafter, the direction parallel to the direction in which the rotation axis CL extends is referred to as the axial direction, the direction radially extending from the rotation axis CL in a plane perpendicular to the rotation axis CL is referred to as the radial direction, and the direction in which the rotor 10 rotates in a plane perpendicular to the rotation axis CL is referred to as the circumferential direction.

[0018] The stator 30 has a stator core 110 provided on the outer side in the radial direction of the rotor core 12 and a stator winding 31 wound around the stator core 110. The stator core 110 has a plurality of electromagnetic steel sheets 101 laminated in the axial direction.

[0019] FIG. 2 is a cross-sectional view showing the configuration of the stator core 110 of the stator 30 according to the first embodiment.

[0020] Since the stator core 110 has a laminated structure in which a plurality of electromagnetic steel sheets 101 are laminated, the portions formed on each electromagnetic steel sheet 101 will form the respective portions of the stator core 110 described below. Therefore, the following description of the shape of the electromagnetic steel sheet 101 also serves as a description of the cross-sectional shape of the stator core 110, and the portion related to the cross-section in the description of the shape of the stator core 110 also serves as a description of the shape of the electromagnetic steel sheet 101.

[0021] The stator core 110 has a cylindrical yoke portion 113 and a plurality of stator teeth 111 that extend radially inward from the yoke portion 113 and are spaced apart from each other in the circumferential direction. Each adjacent stator tooth 111 forms a stator slot 112. The stator winding 31 (Figure 1) passes through the stator slot 112 and is wound around the stator core 110, but is not shown in Figure 2.

[0022] Here, the yoke portion 113 is a cylindrical region sandwiched between an external cylinder 118b that tangent to the base of the stator teeth 111, i.e., the radially outer portion of the stator slot 112, and an external cylinder 118a that tangent to the outer circumferential surface 118 of the stator core 110. The yoke portion 113 becomes the main magnetic path in the stator core 110. Here, the main magnetic path is a passage (magnetic path) that effectively allows the magnetic flux generated by the stator winding 31 (Figure 1) and linked with the rotor core 12 (Figure 1) to pass through. In other words, it is a magnetic path in the stator core 110 where the magnetic resistance is relatively small.

[0023] Eight protrusions 114 are formed on the outer circumferential surface 118 of the stator core 110, projecting radially outward. A connecting plate 120 is provided to connect adjacent protrusions 114.

[0024] In detail, the connecting plate 120 is connected to adjacent projections 114 in the circumferential direction by welds 115. The connecting plate 120 extends along the projections 114 in the axial direction, that is, in the stacking direction of the electrical steel sheet 101.

[0025] The stator core 110 and the connecting plate 120 form a flow path 122, which is a cavity through which a refrigerant such as gas or liquid can flow. More specifically, the outer surface 118 of the electromagnetic steel sheet 101, the protrusion 114, and the connecting plate 120 form an axially extending cooling gas flow path 122.

[0026] Although Figure 2 illustrates a case where eight protrusions 114 are formed, the number is not limited to eight, as long as there are two or more even numbers. Furthermore, if the electromagnetic steel sheets 101 are skewed, that is, stacked while changing angles in the circumferential direction, the protrusions 114 will also be helical rather than parallel to the axial direction. In this case as well, the connecting plate 120 will have a shape that extends diagonally along the protrusions 114.

[0027] Figure 3 is a partial cross-sectional view illustrating the protruding portion 114 and connecting plate 120 of the stator core 110 in the stator 30 according to the first embodiment.

[0028] The connecting plate 120 is connected to each of the two adjacent protrusions 114 by welding, with one surface in contact with the top 114t of each protrusion 114. This welding forms a welded portion 115 on the circumferentially outer side of each protrusion 114.

[0029] Here, the heat input from welding causes a deterioration in the magnetic properties of the protruding portion 114, which is part of the electromagnetic steel sheet 101. This portion where the magnetic properties have deteriorated due to the heat input from welding is called the heat-affected zone 114a. As shown in Figure 3, the range of the heat-affected zone 114a is limited to the radially outer region of the circumscribing cylinder 118a that circumscribes the outer peripheral surface 118; in other words, the range of the heat-affected zone 114a does not extend to the yoke portion 113. In other words, the shape and dimensions of the protruding portion 114 are set so that the range of the heat-affected zone 114a does not extend to the yoke portion 113.

[0030] Figure 4 is a partial cross-sectional view illustrating a modified example of the protruding portion 114 of the stator core 110 and the connecting plate 120 in the stator 30 according to the first embodiment.

[0031] In this modified example, the connection point between the protrusion 114 and the connecting plate 120 is different. Specifically, the connecting plate 120 is welded to each of the opposing inner side portions 114s of two circumferentially adjacent protrusions 114. This welding forms a welded portion 115a on the inner side portion 114s of each protrusion 114 on the circumferentially inner side.

[0032] Similarly, in the modified example, the heat-affected zone 114a remains limited to the radially outer region of the circumscribed cylinder 118a, as shown in Figure 4.

[0033] Figure 5 is a partial cross-sectional view illustrating the requirements for the protrusion 114 of the stator core 110 in the stator 30 according to the first embodiment.

[0034] As shown by the dashed line in Figure 5, a circumscribed square 119 of the circumscribed cylinder 118a of the stator core 110 is assumed in a cross section perpendicular to the axial direction. In this cross section, the protrusion 114 is made to fall within the range of the circumscribed square.

[0035] This requirement assumes a scenario where the electrical steel sheet used as the material is rectangular, and the short side of the sheet is punched out as the diameter. Even in such a case, it is a requirement for forming an electrical steel sheet 101 that has a portion corresponding to the protrusion 114.

[0036] Figure 6 is a cross-sectional view showing the configuration of a stator 30a of a first modified example of the stator according to the first embodiment. The stator 30a according to the first modified example has a stator core 110a made of electromagnetic steel sheet 101a, a connecting plate 120 that connects and integrates the electromagnetic steel sheet 101a, and a stator winding 31 (Figure 1).

[0037] In this first modification, multiple fins 116 are formed to protrude from the outer circumferential surface 118 of the stator core 110a facing the flow channel 122, extending axially. The number of fins 116 may be one. The cross-sectional shape of the fins may be, for example, rectangular, triangular, or trapezoidal. Furthermore, as shown in Figure 6, the fins may have a shape that includes a smooth curved surface in the circumferential direction.

[0038] Figure 7 is a cross-sectional view showing the configuration of a stator 30b of a second modified example of the stator according to the first embodiment. The stator 30b according to the second modified example has a stator core 110, a connecting plate 120a, and a stator winding 31 (Figure 1).

[0039] In the second modification, the stator core 110 is the same as in the first embodiment, and fins 121 are formed on the connecting plate 120a. That is, multiple fins 121 are formed on the surface of the connecting plate 120a facing the flow path 122. The number and cross-sectional shape of the fins 121 are the same as the fins 116 in the first modification.

[0040] Furthermore, a sufficient contact surface is ensured between the top 114t of the protrusion 114 and the connecting plate 120a. As a result, sufficient heat transfer occurs from the electrical steel sheet 101 to the connecting plate 120a, ensuring the heat dissipation function from the fins 121.

[0041] As described above, in the stators 30, 30a, and 30b of this embodiment and its modified versions, the electromagnetic steel sheets 101, 101a can be connected by connecting plates 120, 120a and integrated with the stator cores 110, 110a without causing deterioration of the magnetic properties of the yoke portion 113, which is the main magnetic path portion of the stator cores 110, 110a. As a result, the magnetic performance of the rotating electric machine 1 can be ensured.

[0042] Furthermore, a flow path 122 can be formed to remove heat generated in the stators 30 and 30a. In addition, in the first and second modifications, the heat removal performance can be further improved by the effects of the fins 116 and 121, respectively. As a result, the structural integrity of the rotating electric machine 1 can be maintained.

[0043] [Second Embodiment] Figure 8 is a cross-sectional view showing the configuration of the stator 30c according to the second embodiment.

[0044] The stator 30c comprises a stator core 130 made of electrical steel sheets 101b, connecting plates 140 that connect and integrate the electrical steel sheets 101b, and stator windings (not shown) that penetrate through stator slots 132 formed by stator teeth 131 and are wound around the stator core 130.

[0045] Furthermore, since the stator core 130 has a laminated structure in which multiple electromagnetic steel sheets 101b are stacked, the portions formed on each electromagnetic steel sheet 101b will form the respective portions of the stator core 130 described below. Therefore, the description of the shape of the electromagnetic steel sheets 101b also serves as a description of the cross-sectional shape of the stator core 130, and the portion of the description of the shape of the stator core 130 that relates to the cross-section also serves as a description of the shape of the electromagnetic steel sheets 101b.

[0046] The stator core 130 has a cross-sectional shape in which short sides are formed at the four corners 134 of a square. In other words, the stator core 130 has four core sides 130h and four corner sides 134a, each extending in the axial direction. In a cross-section perpendicular to the axial direction, the four core sides 130h form part of each side of the square. Also, each of the four corner sides 134a is formed at the corner of each adjacent core side 130h.

[0047] Each electrical steel sheet 101b of the stator core 130 is joined and integrated with a connecting plate 140 and a welded joint 138 that are in close contact with the respective corner side surface 134a. The connecting plate 140 has two sides that extend in the axial direction, and the welded joint 138 is formed on each of these sides.

[0048] Now, let's consider an inscribed cylinder 139a that is inscribed within the four iron core sides 130h. The inscribed cylinder 139a and the outer cylinder 139b, which is the radially outer portion of the base of the stator teeth 131, i.e., the stator slot 132, form a cylindrical yoke portion 133. The yoke portion 133 becomes the main magnetic path in the stator iron core 130.

[0049] Here, due to the heat input from welding, a heat-affected zone 134w is formed around the welded portion 138, where the magnetic properties have deteriorated. As shown in Figure 8, the heat-affected zone 134w is confined to the radially outer region of the inscribed cylinder 139a; in other words, the heat-affected zone 134w does not extend to the yoke portion 133.

[0050] Each of the four corners 134 has a flow path hole 135 formed in the shape of an oval or rectangle joined with semicircles on both sides, with its longitudinal direction extending along the corner side surface 134a and its axial direction extending as well. The flow path hole 135 is a cavity through which a refrigerant such as gas or liquid can flow. Each flow path hole 135 is located radially outward of the inscribed cylinder 139a.

[0051] In each corner 134, if the width of the adjacent portions 136 on both sides of the longitudinal direction of the flow path hole 135, in other words, the length in the direction parallel to the corner side surface 134a, is large, it will lead to an increase in leakage magnetic flux. Furthermore, a certain width is necessary for structural integrity. Therefore, it is preferable that the width of the adjacent portions 136 be as small as possible while ensuring the dimensions necessary to guarantee structural integrity.

[0052] Figure 9 is a cross-sectional view showing the configuration of a modified stator according to the second embodiment. The modified stator 30d has a stator core 130a made of electromagnetic steel sheet 101c, a connecting plate 140 that connects and integrates the electromagnetic steel sheet 101c, and a stator winding 31 (Figure 1).

[0053] In this modified example, multiple fins 137 are formed to protrude from the surface of the stator core 130a facing the flow channel hole 135 toward the flow channel hole 135 and extend in the axial direction. The number and shape of the fins 137 are not limited to the example shown in Figure 9, as is the case with the example shown in Figure 6.

[0054] As described above, in the stators 30c and 30d of this embodiment and its modified versions, the electromagnetic steel sheets 101b and 101c can be connected by the connecting plate 140 and integrated with the stator cores 130 and 130a without degrading the magnetic properties of the yoke portion 133, which is the main magnetic path portion of the stator cores 130 and 130a. As a result, the magnetic performance of the rotating electric machine 1 can be ensured.

[0055] Furthermore, flow channels 135 can be formed to remove heat generated in the stators 30c and 30d. In the modified version, the heat removal performance can be further improved by the effect of the fins 137. As a result, the structural integrity of the rotating electric machine 1 can be maintained.

[0056] According to the embodiments described above, it is possible to provide a stator and a rotating electric machine that can reduce the welding influence on a laminated iron core that is integrated by welding and also has a cooling function.

[0057] [Other embodiments] Although embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. Furthermore, the features of each embodiment may be combined. Moreover, the embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0058] 1...Rotating electric machine, 10...Rotor, 11...Rotor shaft, 12...Rotor core, 13...Permanent magnet, 21...Bearing, 22...Bearing bracket, 23...Frame, 30, 30a, 30b, 30c, 30d...Stator, 31...Stator winding, 101, 101a, 101b, 101d...Electromagnetic steel sheet, 110, 110a...Stator core, 111...Stator teeth, 112...Stator slot, 113...Yoke section, 114...Protrusion, 114a...Heat-affected zone, 114s...Inner side section, 114t...Top section, 115...Welded section, 116...Fin, 118...Outer surface, 118a, 118b...Circumscribed cylinder, 119...Circumscribed square, 120, 120a...Contact 121…Fin, 122…Flow channel, 130, 130a…Stator core, 130h…Core side, 131…Stator teeth, 132…Stator slot, 133…Yoke section, 134…Corner section, 134a…Corner side, 134w…Heat-affected zone, 135…Flow channel hole, 136…Adjacent hole section, 137…Fin, 138…Welded section, 139a…Inscribed cylinder, 139b…Outscribed cylinder, 140…Connecting plate, 200…Stator, 201…Stator core, 201a…Yoke section, 201c…Outscribed cylinder, 201s…Outer surface, 201w…Heat-affected zone, 202…Connecting plate, 203…Flow channel, 204…Welded section, 205…Stator teeth, 206…Stator slot

Claims

1. A stator core having multiple laminated electromagnetic steel sheets, the outer surface being cylindrical and having multiple protrusions formed to protrude from the outer surface and extending in the lamination direction, A connecting plate that connects multiple electromagnetic steel sheets and connects adjacent protrusions in the circumferential direction, and forms a refrigerant flow path extending in the stacking direction between itself and the stator core, The stator windings wound around the stator core, A stator characterized by comprising the following:

2. The stator according to claim 1, characterized in that the stator core has fins formed to protrude into the flow path.

3. The stator according to claim 1, characterized in that the connecting plate has fins formed to protrude into the flow path.

4. The protruding portion and the connecting plate are connected by welding. The stator according to claim 1, characterized in that the heat-affected zone due to welding in the protruding portion is confined to a range radially outside the circumscribing cylinder that circumscribing the outer circumferential surface.

5. The stator according to claim 1, characterized in that the connecting plate is connected to the tops or sides of adjacent protrusions.

6. A stator core having multiple laminated electromagnetic steel sheets, with four core sides that form part of each side of a square cross-section and extend in the lamination direction, and corner sides formed between adjacent core sides, with flow holes formed on the inside of each of the four corner sides that extend in the lamination direction and serve as coolant flow paths, A connecting plate for connecting multiple electromagnetic steel sheets, The stator windings wound around the stator core, A stator characterized by comprising the following:

7. The stator according to claim 6, characterized in that the flow path holes are formed on the outside of the inscribed cylinders of the four iron core sides.

8. The stator according to claim 6, characterized in that the stator core has fins formed to protrude into the flow path hole.

9. Rotor and A stator according to any one of claims 1 to 8, A rotating electric machine equipped with the following features.

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