stata

Abstract

Bending the coil reduces the stress transmitted to the stator core. [Solution] The stator comprises a stator core, a coil attached to the stator core with a portion inserted into a slot 14 formed in the stator core, and insulating paper 30 inserted into the slot to insulate the stator core from the coil. The first surface of the coil, which faces the direction in which the coil end 23 protruding from the axial end face of the stator core is bent, has a recess 25a in the area facing the corner of the slot opening 18 at the end face.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a stator.

Background Art

[0002] Patent Document 1 discloses that a strip coil is mounted along the circumferential direction of a stator core by inserting a straight portion of the strip coil wound in an annular shape into a slot having insulating paper from the inside of the stator core.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When manufacturing a stator by attaching a coil to a stator core, a coil end portion, which is a portion protruding from an end surface of the stator core, is bent and processed. When stress acts on the stator core as the coil is bent, a part of the stator core may be damaged, leading to energy loss in a motor including the stator in its configuration. Conventionally, in such a situation, a method has been adopted in which a specific jig is arranged near the root of the coil end portion to reduce the stress transmitted to the stator core due to the bending of the coil.

[0005] However, according to the above method, there is a problem that the height of the coil end portion from the end surface of the stator core increases in order to secure a space for arranging the jig near the root of the coil end portion. Also, using the above-described jig increases the cost of manufacturing the stator.

Means for Solving the Problems

[0006] This specification discloses a stator comprising a stator core, a coil attached to the stator core with a portion inserted into a slot formed in the stator core, and insulating paper inserted into the slot to insulate the stator core from the coil. According to the stator, a first surface of the coil, facing the direction in which the coil end protruding from the axial end face of the stator core is bent, has a recess in the area facing the corner of the opening of the slot on the end face.

[0007] According to the above configuration, since the first surface of the coil has a recess, the stress acting on the stator core due to bending of the coil end is reduced. In other words, it is possible to reduce the stress acting on the stator core while avoiding the inconveniences that arise when using conventional jigs. [Brief explanation of the drawing]

[0008] [Figure 1] A simplified perspective view showing the structure of the stator. [Figure 2] A simplified diagram showing the general method of assembling the stator. [Figure 3] A flowchart showing how to assemble the stator. [Figure 4] A perspective view showing a portion of the stator from the second end face side. [Figure 5] A diagram showing one slot from a viewpoint opposite the second end face. [Figure 6] Figure 5 shows a cross-section along the line VI-VI. [Modes for carrying out the invention]

[0009] The main features of the embodiments described below are listed. These features can be combined in any way. According to the stator disclosed herein, the first surface and the corner of the opening may not be in contact when the coil end is bent. According to the above configuration, since the first surface of the coil has a recess, the first surface and the corner of the opening do not come into contact when the coil end is bent. Therefore, stress acting on the stator core due to bending of the coil end is avoided.

[0010] According to the stator disclosed herein, the edges of the insulating paper may protrude from the end face and cover at least a portion of the recess. According to the above configuration, even if the coil end is bent and the recess on the first surface of the coil comes so close that it comes into contact with the corner of the opening, insulation between the two close contacts is ensured by the insulating paper.

[0011] According to the stator disclosed herein, the coil is composed of a plurality of segment coils connected together, the slot is formed extending radially from the stator core, a predetermined number of the segment coils are inserted into the slot in a line along the radial direction, the first surface of each segment coil has the recess, and the coil end of each segment coil is bent in a direction intersecting the radial direction. According to the above configuration, since the first surface of each segment coil has a recess, the stress acting on the stator core due to the bending of the coil ends of each segment coil is reduced.

[0012] This embodiment will be described with reference to the drawings. Each figure is for illustrative purposes only, and this embodiment is not limited to what is shown. Also, since each figure is illustrative, some parts may be omitted.

[0013] Figure 1 shows a simplified perspective view of the stator 10. The stator 10 generally comprises a stator core 11 and coils 12. The stator 10 is a component of a motor driven by electric power. The concept of a motor includes various types of motors, such as DC (direct current) motors, AC (alternating current) motors, stepping motors, and servo motors.

[0014] The specific configuration and material of the stator core 11 are not particularly limited. For example, the stator core 11 is generally cylindrical and is composed of multiple silicon steel plates laminated together. Hereinafter, the radial direction, circumferential direction, and axial direction of the stator core 11 will be simply referred to as the radial direction, circumferential direction, and axial direction, respectively. The axial direction is the direction parallel to the central axis Ax of the stator core 11. The radial direction is the direction perpendicular to the central axis Ax and extends radially from the central axis Ax. In the radial direction, the side closer to the central axis Ax is the radially inner side, and the side farther from the central axis Ax is the radially outer side.

[0015] Multiple teeth 13 are projected radially inward from the inner circumference of the stator core 11. The multiple teeth 13 are arranged along the circumferential direction. The gaps between adjacent teeth 13 in the circumferential direction are called slots 14. All of the multiple slots 14 formed in the stator core 11 are open to the inner circumferential surface and both axially oriented end faces of the stator core 11. One axially oriented end face of the stator core 11 is called the first end face 15, and the other axially oriented end face of the stator core 11 is called the second end face 16.

[0016] The coil 12 is mounted on the stator core 11 with a portion of it inserted into each slot 14 of the stator core 11. It can also be said that the coil 12 is wound around multiple tooth sections 13 and extends circumferentially. The coil 12 corresponds, for example, to three coils corresponding to a three-phase AC voltage, i.e., three coils corresponding to the U-phase, V-phase, and W-phase. Power is supplied to such coils 12 from an inverter (not shown) located outside the stator 10.

[0017] FIG. 2 schematically shows an overview of the method of assembling the stator 10. FIG. 3 shows the method of assembling the stator 10 in a flowchart. In the upper part of FIG. 2, the segment coil 20 which is a unit constituting the coil 12 is simply shown. The segment coil 20 is generally U-shaped and includes two lead portions 21 and a curved portion 22 connecting the two lead portions 21. The lead portion 21 may be called, for example, a straight portion. Also, the curved portion 22 may be called, for example, an anti-lead portion. The segment coil 20 is formed, for example, by bending a flat conductor having a rectangular cross-sectional shape. Although omitted in FIG. 2, a crank portion may be formed, for example, near the center of the curved portion 22 in order to change the lane between one lead portion 21 and the other lead portion 21. Reference numeral 23 indicates the coil end portion 23 which is the tip side portion of each lead portion 21.

[0018] In step S100, an insulating paper is inserted into the stator core 11. That is, the insulating paper 30 (see FIG. 5 etc.) is inserted into the slot 14 of the stator core 11. The insulating paper 30 is inserted to insulate the stator core 11 and the coil 12. The insulating paper 30 is a sheet-like insulating material having insulating properties and flexibility. The insulating paper 30 is also called a multi-layer laminate material or the like. The method of inserting the insulating paper 30 into the slot 14 is not particularly limited. The insulating paper 30 is inserted into the slot 14, for example, through the opening of the slot 14 formed in the first end face 15 or the opening 18 of the slot 14 formed in the second end face 16. Alternatively, the insulating paper 30 may be inserted into the slot 14 from the inner peripheral surface side of the stator core 11. Step S100 corresponds to an example of the "insulating paper insertion process".

[0019] In step S110, the segment coil 20 is inserted inside the insulating paper 30 within the slot 14 of the stator core 11. In the middle and lower parts in FIG. 2, a part of the stator core 11 is shown from the inner peripheral surface side. As shown in the middle part in FIG. 2, from the side of the first end face 15 of the stator core 11, the lead part 21 which is a part of the coil 12 is inserted into the slot 14. The two lead parts 21 of one segment coil 20 are inserted into different slots 14. As a result, the segment coil 20 is in a state where the curved part 22 protrudes from the first end face 15 and the coil end part 23 protrudes from the second end face 16. In FIG. 2, the description of the insulating paper 30 is omitted. Step S110 corresponds to an example of the "coil insertion process".

[0020] In step S120, the bending and joining of the coil end part 23 protruding from the second end face 16 of the stator core 11 are carried out. The concept of bending may be understood to include the process of twisting the object. The coil end parts 23 which were linear when inserted from the first end face 15 side and protruded from the second end face 16 are respectively bent or twisted appropriately in the circumferential direction and the radial direction, and are joined to the coil end parts 23 of other segment coils 20 by welding or the like as shown in the lower part in FIG. 2. Step S120 corresponds to an example of the "bending process".

[0021] The part where different segment coils 20 are joined to each other's coil end parts 23 is called the joining part 24. When the plurality of segment coils 20 inserted into the stator core 11 are joined by their coil end parts 23, a continuous coil 12 (for example, the coil 12 corresponding to the U phase) is formed. That is, the coil 12 is constituted by connecting a plurality of segment coils 20.

[0022] Figure 4 shows a perspective view of a portion of the stator 10 from the second end face 16 side. Figure 4 shows multiple joints 24 where bent coil ends 23 are joined together. In step S110, multiple segment coils 20 are inserted into each slot 14 of the stator core 11 from the first end face 15 side, in an annular arrangement, for example, by a known annular alignment method. Regarding the method of connecting the segment coils 20, such as how the coil ends 23 are connected in relation to each other on the second end face 16 side, various connection patterns have been proposed, so this embodiment will not specifically mention them. The assembly method of the stator 10 may also include one or more steps not shown in Figure 3.

[0023] Figure 5 shows a single slot 14 and the insulating paper 30 and multiple segment coils 20 inserted into the slot 14, from a viewpoint facing the second end face 16 of the stator core 11. The opening 18 of the slot 14 is formed on the second end face 16. The slot 14 extends radially outward from the inner circumferential surface of the stator core 11. In other words, the slot 14 is formed to extend radially. A predetermined number (10 in Figure 5) of segment coils 20 are inserted into the slot 14, arranged radially. Figure 5 shows the cross-section of each segment coil 20 inserted into the slot 14. These cross-sections of each segment coil 20 may be understood as the cross-section of each lead portion 21 or each coil end portion 23 of each segment coil 20. In the figure, the segment coils 20 that appear to be adjacent and touching are insulated from each other except for the joint portion 24.

[0024] According to Figure 5, insulating paper 30 is housed within the slot 14 so as to enclose a predetermined number of segment coils 20 together. Figure 4 also shows a simplified view of the opening 18 of the slot 14 and the insulating paper 30. In the example in Figure 5, wedge paper 32 is inserted into the innermost radial position within the slot 14. The wedge paper 32 is held in place by protrusions provided at the tips of the teeth 13 on both sides of the slot 14, which protrude into the slot 14. The wedge paper 32 has the function of holding down the tip of the folded insulating paper 30 and acts as a spacer to eliminate gaps within the slot 14.

[0025] Figure 5 shows the bending directions D1 and D2 for each segment coil 20 arranged radially within the slot 14, in which the coil end 23 is bent at step S120. Bending directions D1 and D2 are both directions that intersect the radial direction and are opposite to each other. Furthermore, it can be said that bending directions D1 and D2 are both roughly aligned with the circumferential direction. According to Figure 5, the coil end 23 of each segment coil 20 arranged radially within the slot 14 is bent alternately in bending direction D1 and bending direction D2.

[0026] Figure 6 shows a cross-section along the line VI-VI in Figure 5. However, in Figure 6, hatching is not applied to the cross-section of the insulating paper 30 for clarity. In the segment coil 20 shown in Figure 6, the coil end 23 is bent in the bending direction D1. The surface of the coil 12 that faces the bending direction of the coil end 23 is called the "first surface 25". If the coil end 23 is a lead portion 21 that is bent in the bending direction D1, then the surface facing the bending direction D1 corresponds to the first surface 25. On the other hand, if the coil end 23 is a lead portion 21 that is bent in the bending direction D2, then the surface facing the bending direction D2 corresponds to the first surface 25.

[0027] As shown in Figures 5 and 6, the first surface 25 has a recess 25a in the area facing the corner 18a of the opening 18 in the second end surface 16. The recess 25a is open in the bending direction of the coil end 23, radially inward, and radially outward. The recess 25a increases the distance between the first surface 25 and the corner 18a of the opening 18. As can be seen from Figure 5, each first surface 25 of the segment coil 20 inserted into the slot 14 has a recess 25a.

[0028] As shown in Figure 6, the cross-sectional shape of the recess 25a perpendicular to the radial direction is rectangular, but the shape of the recess 25a is not limited to the illustrated example. The shape of the recess 25a may be, for example, the result of a part of the first surface 25 being cut out in a V-shape, semicircle, trapezoid, or other polygonal shape. Note that the recess 25a is also shown in Figure 4.

[0029] With this configuration, since the first surface 25 of the coil 12 has a recess 25a, the stress acting on the stator core 11 due to bending of the coil end 23 is reduced without the use of conventional jigs. As shown in Figure 6, even when the coil end 23 is bent, the recess 25a is located between the first surface 25 and the corner 18a of the opening 18, so the first surface 25 and the corner 18a of the opening 18 do not come into contact. Therefore, the stress acting on the stator core 11 due to bending of the coil end 23 is avoided. Alternatively, even if the coil end 23 is bent to the extent that the recess 25a presses against the corner 18a of the opening 18, the stress transmitted from the segment coil 20 to the stator core 11 when the coil end 23 is bent is reduced compared to the case where the recess 25a is not formed. In this specification, reduction of stress acting on the stator core 11 includes both a decrease in stress and a stress becoming substantially zero.

[0030] As shown in Figure 6, the end of the insulating paper 30 may protrude from the second end face 16. The end of the insulating paper 30 protruding from the second end face 16 may be folded, as in the example in Figure 4. The end of the insulating paper 30 protruding from the second end face 16 may cover at least a portion of the recess 25a. According to Figure 6, of the opening of the recess 25a facing the bending direction D1, the portion within the stator core 11 is entirely covered by the insulating paper 30, and the portion outside the stator core 11 is partially or entirely covered by the insulating paper 30. Because the recess 25a is covered by the insulating paper 30, even if the recess 25a of the first surface 25 and the corner 18a of the opening 18 come into close contact, insulation between the two is ensured by the insulating paper 30. In addition, the cushioning properties of the insulating paper 30 reduce the stress transmitted from the coil 12 to the stator core 11. Furthermore, a configuration in which the insulating paper 30 does not protrude from the second end face 16 or the first end face 15 of the stator core 11 is also within the scope of disclosure of this specification.

[0031] The specific examples of the technologies disclosed herein have been described in detail above, but these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples described above. Furthermore, the technical elements described herein or in the drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated herein or in the drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself. [Explanation of Symbols]

[0032] 10: Stator, 11: Stator core, 12: Coil, 13: Teeth section, 14: Slot, 15: First end face, 16: Second end face, 18: Opening, 18a: Corner, 20: Segment coil, 21: Lead section, 22: Curved section, 23: Coil end, 24: Joint, 25: First surface, 25a: Recess, 30: Insulating paper

Claims

1. Stator core and A coil attached to the stator core with a portion of it inserted into a slot formed in the stator core, The system includes insulating paper inserted into the slot to insulate the stator core and the coil, A stator in which the first surface of the coil, facing the direction in which the coil end protruding from the axial end face of the stator core is bent, has a recess in the area facing the corner of the opening of the slot on the end face.

2. The stator according to claim 1, wherein, when the coil end is bent, the first surface and the corner of the opening are not in contact.

3. The stator according to claim 1, wherein the end of the insulating paper protrudes from the end face and covers at least a portion of the recess.

4. The aforementioned coil is constructed by connecting multiple segment coils. The aforementioned slot is formed extending radially from the stator core, A predetermined number of the segment coils are inserted into the slots in a line along the radial direction. The first surface of each segment coil is provided with the recess, The stator according to claim 1, wherein the coil end of each segment coil is bent in a direction intersecting the radial direction.

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