Stator and stator assembly method

Abstract

As the coil is bent, stress is applied 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 formed in the stator core, and insulating paper inserted into the slot to insulate the stator core from the coil. The opening of the slot on the axial end face of the stator core has an enlarged portion whose width is widened in a direction corresponding to the direction in which the coil end protruding from the end face of the coil is bent, and a portion of the insulating paper is housed in the enlarged portion in a double or more overlapping state.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a stator and a method for assembling a stator.

Background Art

[0002] Patent Document 1 discloses insulating paper that is inserted into slots formed in a stator core constituting a motor. The insulating paper insulates the stator core and a coil inserted into the slots. According to Patent Document 1, the insulating paper has a non-protruding portion housed inside the slot and a protruding portion protruding in the axial direction of the stator core from the end of the slot.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to Patent Document 1, it is proposed that even when the bending stress of the coil acts on the protruding portion of the insulating paper as the coil is bent during coil processing, the stress is relaxed by the stress relaxation portion of the protruding portion, and damage to the protruding portion is suppressed. However, in Patent Document 1, it is not possible to reduce the stress acting on the stator core as the coil is bent. If strong stress acts on the stator core, it may lead to partial damage of the stator core or energy loss of the motor.

Means for Solving the Problems

[0005] 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. In this stator, the opening of the slot on the axial end face of the stator core has an enlarged portion whose width is widened in a direction corresponding to the direction in which the coil end protruding from the end face of the coil is bent, and a portion of the insulating paper is housed in the enlarged portion in a double or more overlapping state.

[0006] According to the above configuration, the stress acting on the stator core due to the bending of the coil ends is reduced by the insulating paper housed in the enlarged section in a double or more overlapping state.

[0007] This specification discloses a method for assembling a stator. The method comprises an insulating paper insertion step of inserting insulating paper into a slot formed in the stator core, the slot having an opening on the axial end face of the stator core; a coil insertion step of inserting a portion of a coil into the slot and inside the insulating paper; and a bending step of bending the coil end that protrudes from the end face of the coil. The opening has an enlarged portion whose width is increased in the direction in which the coil end is bent in the bending step, and in the insulating paper insertion step, a portion of the insulating paper is housed in the enlarged portion in a state where it overlaps in two or more layers. [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. [Figure 7] This figure shows one slot in a different example from Figure 5, viewed from a perspective opposite the second end face. [Figure 8] Figure 7 shows a cross-section along the line VIII-VIII. [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 end of the insulating paper may be folded and housed in the enlarged portion. According to the above configuration, by simply folding the edges of the insulating paper, a portion of the insulating paper can be stored in the enlarged section in a state where it is layered two or more times.

[0010] 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, and the coil end of each segment coil is bent in a direction intersecting the radial direction. According to the above configuration, the stress acting on the stator core when the coil ends of each segment coil are bent can be reduced by the insulating paper housed in the enlarged section in a double or more overlapping state.

[0011] According to the stator disclosed herein, the enlarged portion may be formed continuously in the area where the predetermined number of segment coils are arranged. According to the above configuration, it becomes easier to form an opening with an enlarged portion.

[0012] According to the stator disclosed herein, the enlarged portion may be formed in a range where a predetermined number of segment coils are arranged, with each individual segment coil corresponding to one-to-one and spaced apart from one another. According to the above configuration, the amount by which the stator core is cut out by forming the enlarged portion can be minimized.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] On the inner circumference of the stator core 11, a plurality of teeth 13 project radially inward. The plurality of teeth 13 are arranged along the circumferential direction. Each gap between adjacent teeth 13 in the circumferential direction is called a slot 14. All of the plurality of slots 14 formed in the stator core 11 are open to the inner circumferential surface of the stator core 11 and both end faces facing the axial direction. One end face facing the axial direction of the stator core 11 is called the first end face 15, and the other end face facing the axial direction of the stator core 11 is called the second end face 16.

[0017] The coil 12 is attached to the stator core 11 with a part thereof inserted into each slot 14 of the stator core 11. It can also be said that the coil 12 is wound around the plurality of teeth 13 and extends along the circumferential direction. The coil 12 corresponds to each of, for example, three-phase coils corresponding to a three-phase AC voltage, that is, three coils corresponding to the U-phase, V-phase, and W-phase. Power is supplied to such a coil 12 from an inverter (not shown) outside the stator 10.

[0018] Figure 2 simply shows an outline of the assembling method of the stator 10. Figure 3 shows the assembling method of the stator 10 in a flowchart. In the upper part of Figure 2, a 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, a reverse lead portion. The segment coil 20 is formed, for example, by bending a flat conductor having a rectangular cross-sectional shape. Although omitted in Figure 2, a crank portion may be formed near the center of the curved portion 22, for example, to change the lane between one lead portion 21 and the other lead portion 21. Reference numeral 23 indicates a coil end portion 23 which is a portion on the tip side of each lead portion 21.

[0019] In step S100, insulating paper is inserted into the stator core 11. That is, insulating paper 30 (see Figure 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 from the coil 12. The insulating paper 30 is a sheet-like insulating material that has insulating and flexible properties. The insulating paper 30 is also called a multilayer laminate material. There is no particular method for inserting the insulating paper 30 into the slot 14. For example, the insulating paper 30 is inserted into the slot 14 through an opening in the slot 14 formed on the first end face 15 or an opening 18 in the slot 14 formed on the second end face 16. Alternatively, the insulating paper 30 may be inserted into the slot 14 from the inner circumferential surface side of the stator core 11. Step S100 is an example of an "insulating paper insertion process".

[0020] In step S110, the segment coil 20 is inserted into the slot 14 of the stator core 11, inside the insulating paper 30. In the middle and lower sections of Figure 2, a portion of the stator core 11 is shown from the inner circumferential surface side. As shown in the middle section of Figure 2, the lead portion 21, which is part of the coil 12, is inserted into the slot 14 from the side of the first end face 15 of the stator core 11. The two lead portions 21 of one segment coil 20 are inserted into different slots 14. As a result, the segment coil 20 has a curved portion 22 protruding from the first end face 15 and a coil end portion 23 protruding from the second end face 16. Note that the insulating paper 30 is not shown in Figure 2. Step S110 is an example of the "coil insertion process".

[0021] In step S120, the coil ends 23 protruding from the second end face 16 of the stator core 11 are bent and joined. The concept of bending may be understood to include the process of twisting the object. The coil ends 23, which were straight when inserted from the first end face 15 side and protruding from the second end face 16, are bent and twisted as appropriate in the circumferential and radial directions, and are joined to the coil ends 23 of other segment coils 20 by welding or the like, as shown in the lower part of Figure 2. Step S120 is an example of a "bending process".

[0022] The area where different segment coils 20 are joined at their coil ends 23 is called the joint 24. Multiple segment coils 20 inserted into the stator core 11 are joined at their coil ends 23 to form a single coil 12 (for example, a coil 12 corresponding to the U phase). In other words, the coil 12 is constructed by connecting multiple segment coils 20.

[0023] 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.

[0024] 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 can be understood as the cross-section of each lead portion 21 that each segment coil 20 has. 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.

[0025] 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.

[0026] 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.

[0027] 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. The segment coil 20 inserted into the slot 14 is shown by a dashed line. As shown in Figures 5 and 6, the opening 18 of the slot 14 has an enlarged section 18a whose width is widened in accordance with the bending directions D1 and D2 to which the coil end 23 protruding from the second end face 16 is folded. A portion of the insulating paper 30 is housed in the enlarged section 18a in a state of overlapping two or more layers. That is, in step S100, a portion of the insulating paper 30 is housed in the enlarged section 18a in a state of overlapping two or more layers.

[0028] In the explanation of Figures 5 and 6, width refers to the width in the direction intersecting the radial direction, and can be simply understood as the width in the circumferential direction. The width W1 of the part of the slot 14 that does not correspond to the enlarged portion 18a is basically roughly equivalent to the width of the lead portion 21 plus the thickness of the insulating paper 30 × 2. The width W2 of the opening 18 including the enlarged portion 18a is larger than the width W1 and is large enough to accommodate insulating paper 30 that is doubled or more on the outside of the lead portion 21. Note that it is "doubled or more," so it could be tripled or quadrupled or more, but in the example of Figure 6 and Figure 8 described later, the insulating paper 30 housed in the enlarged portion 18a is doubled.

[0029] In the enlarged section 18a, it is sufficient for the insulating paper 30 to be layered in two or more layers; for example, the insulating paper 30 may be layered on top of each other after being separated from each other. Also, as an example, the edges of the insulating paper 30 may be folded and housed in the enlarged section 18a. In Figure 6, the edge of the insulating paper 30 on the side of the opening 18 is folded outwards, resulting in a double layer of insulating paper 30, and this folded portion is housed in the enlarged section 18a.

[0030] With this configuration and method, when the coil end 23 is bent in step S120, the stress acting on the stator core 11, particularly the corners of the opening 18, is reduced by the insulating paper 30 housed in the enlarged portion 18a in a double or more overlapping state. In other words, the cushioning effect provided by the double or more overlapping insulating paper 30 reduces the stress transmitted from the segment coil 20 to the stator core 11 when the coil end 23 is bent. As a result, partial damage to the stator core 11 and energy loss of the motor are suppressed.

[0031] As explained with reference to Figure 5, each segment coil 20 inserted into the slot 14 has its coil end 23 bent in either the bending direction D1 or the bending direction D2. Therefore, the enlarged portion 18a is formed on both the bending direction D1 side and the bending direction D2 side.

[0032] As shown in Figure 5, the enlarged portion 18a is formed continuously in the area where a predetermined number of segment coils 20 are arranged within the slot 14. More specifically, the enlarged portion 18a is formed continuously along the radial direction in both the bending direction D1 and the bending direction D2, over the area where the segment coils 20 are arranged within the slot 14. In addition, the insulating paper 30 is housed in the enlarged portion 18a in a double or more overlapping state over the area where the segment coils 20 are arranged within the slot 14 in both the bending direction D1 and the bending direction D2. This configuration facilitates the process of forming the opening 18 with the enlarged portion 18a in the stator core 11 and housing the insulating paper 30 in a double or more overlapping state within the enlarged portion 18a.

[0033] Figure 7 shows the slot 14, etc., from the same viewpoint as in Figure 5, to illustrate an enlarged section 18a of an example different from Figures 5 and 6. Figure 8 shows the cross section along line VIII-VIII in Figure 7, in the same way as in Figure 6. For Figures 7 and 8, explanations that are common to the explanations for Figures 5 and 6 are omitted.

[0034] As shown in Figures 7 and 8, the enlarged portions 18a are formed in a one-to-one correspondence with each individual segment coil 20 within the range where a predetermined number of segment coils 20 are arranged in the slot 14, and are spaced apart from each other. In other words, the enlarged portions 18a may be formed only on the bending direction D1 side, corresponding to the segment coil 20 (lead portion 21) whose coil end 23 is bent in the bending direction D1 (see Figure 8), and also formed only on the bending direction D2 side, corresponding to the segment coil 20 (lead portion 21) whose coil end 23 is bent in the bending direction D2. In the example in Figure 7, five enlarged portions 18a are formed radially spaced apart from each other on the bending direction D1 side, corresponding one-to-one with five segment coils 20 (lead portions 21) whose coil end 23 is bent in the bending direction D1. Furthermore, in the example shown in Figure 7, five enlarged portions 18a are formed radially spaced apart from each other on the bending direction D2 side, corresponding one-to-one to the five segment coils 20 (lead portions 21) whose coil ends 23 are bent in the bending direction D2.

[0035] Each of the multiple spaced-apart enlarged portions 18a is housed with two or more layers of insulating paper 30. In Figure 8, as in Figure 6, the width W2 of the opening 18 including the enlarged portions 18a is greater than the width W1. However, the width W2 shown in Figure 8 is smaller than the width W2 shown in Figure 6 because it includes the enlarged portions 18a formed only on the bending direction D1 side of the coil end 23. With this configuration shown in Figures 7 and 8, the enlarged portions 18a are formed only at the positions necessary to reduce the stress transmitted from the segment coil 20 to the stator core 11 when the coil end 23 is bent. Therefore, the amount of the stator core 11 cut out by the formation of the enlarged portions 18a can be minimized.

[0036] 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]

[0037] 10: Stator, 11: Stator core, 12: Coil, 13: Teeth section, 14: Slot, 15: First end face, 16: Second end face, 18: Opening, 18a: Enlarged section, 20: Segment coil, 21: Lead section, 22: Curved section, 23: Coil end, 24: Joint section, 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, The opening of the slot on the axial end face of the stator core has an enlarged portion whose width is increased in a direction corresponding to the direction in which the coil end protruding from the end face of the coil is bent. A stator in which a portion of the insulating paper is housed in the enlarged section in a state where it is overlapped in two or more layers.

2. The stator according to claim 1, wherein the end of the insulating paper is folded and housed in the enlarged portion.

3. 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 stator according to claim 1, wherein the coil end of each segment coil is bent in a direction intersecting the radial direction.

4. The stator according to claim 3, wherein the enlarged portion is continuously formed in the area where the predetermined number of segment coils are arranged.

5. The stator according to claim 3, wherein the enlarged portion is formed in a range where the predetermined number of segment coils are arranged, with each individual segment coil corresponding to one-to-one and spaced apart from one another.

6. An insulating paper insertion step involves inserting insulating paper into a slot formed in the stator core, the slot having an opening on the end face facing the axial direction of the stator core, A coil insertion step involves inserting a portion of the coil into the slot and inside the insulating paper, The process includes a bending step of bending the coil end that protrudes from the end face of the coil, The opening is provided with an enlarged portion whose width is increased in the direction in which the coil end is bent by the bending process, A method for assembling a stator, wherein in the insulating paper insertion step, a portion of the insulating paper is housed in the enlarged section in a state where it is overlapped in two or more layers.

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