Stator and method for assembling stator

Abstract

A stator (1) according to one embodiment includes: a stator core (2) including N teeth (21) (N is an even number); and N coils (4) inserted into the teeth (21). The stator core (2) is divided into N segments (3) along a dividing line (11) passing through the teeth (21). Each segment (3) includes an arc-shaped yoke part (31), a first tooth part (32) and a second tooth part (33) protruding radially inward from both ends of the yoke part (31), and a rib (34) extending from the tip of the first tooth part (32) to the side opposite to the second tooth part (33) and covering a part of the coil (4).

Description

Stator and stator assembly method

[0001] The present disclosure relates to a stator for an electric motor and a method for assembling said stator.

[0002] It has been known in the past to improve the efficiency of electric motors by forming air-core coils in advance and inserting the air-core coils into the teeth, rather than winding wire around the teeth of a stator core to form coils. For example, Patent Document 1 discloses a stator 100 as shown in Fig. 5. In the stator 100, a stator core 110 including N teeth 120 is divided into N segments 130 along dividing lines that pass through the teeth 120.

[0003] More specifically, the segment 130 includes alternating first division bodies 140 and second division bodies 150 that are different in shape from each other. Each first division body 140 includes an arc-shaped first yoke portion 141 and first tooth portions 142, 143 that protrude radially inward from both ends of the first yoke portion 141. In Patent Document 1, the first yoke portion 141 is referred to as the "first divided core back" and the first tooth portions 142, 143 are referred to as the "first divided teeth."

[0004] Similarly, each second divided body 150 includes an arc-shaped second yoke portion 151 and second tooth portions 152, 153 that protrude radially inward from both ends of the second yoke portion 151. In Patent Document 1, the second yoke portion 151 is called the "second divided core back," and the second tooth portions 152, 153 are called the "second divided teeth."

[0005] The first tooth portion 142 of each first divided body 140 forms one tooth 120 together with the second tooth portion 153 of the adjacent second divided body 150, and the first tooth portion 143 of each first divided body 140 forms one tooth 120 together with the second tooth portion 152 of the oppositely adjacent second divided body 150. Coils 160 are inserted through all of the teeth 120.

[0006] Furthermore, in the stator 100 of Patent Document 1, an umbrella 144 is provided at the tip of one of the first tooth portions 143 of each first segment 140, extending toward the other first tooth portion 142. The gap between the umbrella 144 and the first tooth portion 142 is set larger than the thickness of the coil 160 so that the coil 160 can be inserted into the first tooth portion 142. The umbrella 144 covers, from the radial inside of the stator 100, a portion of the coil 160 inserted into the tooth 120, which is composed of the first tooth portion 143 with the umbrella 144 provided at its tip and the second tooth portion adjacent to the first tooth portion 143.

[0007] Japanese Patent Application Laid-Open No. 2021-136726

[0008] However, in the stator 100 of Patent Document 1, the umbrella 144 is only provided on the first division 140, so the coil 160 inserted into the tooth 120 composed of the first tooth portion 142 on the side of the first division 140 where the umbrella 144 is not provided and the second tooth portion 153 of the second division 150 is not covered from the radial inside of the stator 100.

[0009] Therefore, an object of the present disclosure is to provide a stator that can cover all coils from the radially inner side of the stator, and a method for assembling the stator.

[0010] From one aspect, the present disclosure provides a stator comprising a stator core including N teeth (N is an even number) and N coils inserted into the teeth, wherein the stator core is divided into N segments along dividing lines passing through the teeth, and each segment includes an arc-shaped yoke portion, a first tooth portion and a second tooth portion protruding radially inward from both ends of the yoke portion, and a rib extending from the tip of the first tooth portion to the opposite side from the second tooth portion and covering a portion of the coil inserted into the tooth formed by the first tooth portion and the second tooth portion of an adjacent segment.

[0011] From another aspect, the present disclosure provides a method for assembling a stator including a stator core including N teeth (N is an even number) and N coils inserted into the teeth, the method comprising: preparing air-core coils as the coils; dividing the stator core into N segments along dividing lines passing through the teeth; each segment including an arc-shaped yoke portion, a first tooth portion and a second tooth portion protruding radially inward from both ends of the yoke portion, and a rib extending from a tip of the first tooth portion to a side opposite the second tooth portion; inserting the coils into the first tooth portion of each segment to form N coil-holding segments; The method for assembling a stator includes: bringing a coil into contact with the second tooth side surface of a first tooth portion in a stator; inserting the second tooth portion of another coil holding segment into a gap formed between the inner surface of the coil and the surface of the first tooth portion opposite the second tooth portion; connecting half of the coil holding segments to form two stator halves; and inserting the second tooth portion of a coil holding segment located at the other end of the two stator halves into the gap between the inner surface of the coil in the coil holding segment located at one end of the two stator halves and the surface of the first tooth portion opposite the second tooth portion.

[0012] According to the present disclosure, there is provided a stator capable of covering all coils from the radially inner side of the stator, and a method for assembling the stator.

[0013] Fig. 3A is a cross-sectional view of a stator according to one embodiment; Fig. 3B is an enlarged view of one segment and one coil of a stator core; Fig. 3C is a diagram illustrating state changes when one coil is inserted into a first tooth portion of one segment; Fig. 3D is a diagram illustrating a method of assembling a stator; Fig. 3E is a cross-sectional view of a conventional stator; Fig. 3F is a diagram illustrating a method of assembling a stator; Fig. 3G is a diagram illustrating a method of assembling a stator; Fig. 3H is a diagram illustrating a method of assembling a stator; Fig. 3H is a diagram illustrating a method of assembling a stator; Fig. 3I is a diagram illustrating a method of assembling a stator; Fig. 3J is a diagram illustrating a method of assembling a stator; Fig. 3J is a diagram illustrating a method of assembling a stator; Fig. 3I ...

[0014] 1 shows a stator 1 according to one embodiment. The stator 1 is hollow, and a rotor is disposed inside the stator 1. The stator 1 and the rotor, together with a rotating shaft that passes through the rotor, constitute an electric motor.

[0015] The stator 1 includes a stator core 2 having N teeth 21 (N is an even number), and N coils 4 inserted into the teeth 21. In this embodiment, N=12, but N may be 4, 6, 8, 10, 14, etc. An insulating material may be interposed between the coils 4 and the stator core 2.

[0016] In this embodiment, the teeth 21 are straight and each tooth 21 has a pair of parallel side surfaces, so that a slot having a sector-shaped cross section is formed between the teeth 21 .

[0017] The stator core 2 is divided into N segments 3 along division lines 11 that pass through the teeth 21. The division lines 11 extend radially from the central axis 10 of the stator 1. In this embodiment, at the tip of each tooth 21, the division lines 11 bend obliquely toward the radially inward direction so as to reach the side of the tooth 21. That is, as shown in FIG. 2 , each division line 11 has a radially extending portion 11a that is parallel to the radial direction and centered on the central axis 10 of the stator 1, and an inclined portion 11b that is located radially inward of the radially extending portion 11a.

[0018] Each segment 3 may have a structure in which a plurality of annular electromagnetic steel plates or amorphous ribbons are stacked in the axial direction of the stator 1, or may be entirely made of soft magnetic powder.

[0019] 2, each segment 3 includes an arc-shaped yoke portion 31, and a first tooth portion 32 and a second tooth portion 33 that protrude radially inward from both ends of the yoke portion 31. The first tooth portion 32 forms a tooth 21 together with the second tooth portion 33 of the adjacent segment 3, and the second tooth portion 33 forms a tooth 21 together with the first tooth portion 32 of the oppositely adjacent segment 3.

[0020] Therefore, when viewed from one coil 4, the inner surface of the coil 4 contacts the first tooth portion 32 and the second tooth portion 33 of the adjacent segment 3, and the outer end surface of the coil 4 contacts both yoke portions 31 of the adjacent segment 3.

[0021] In this embodiment, the radially extending portion 11a of the parting line 11 passes through a position offset from the center of the tooth 21. Therefore, the width A of the first tooth portion 32 is smaller than the width B of the second tooth portion 33. For example, A:B is within the range of 1:1.5 to 1:4.5.

[0022] Furthermore, each segment 3 includes a rib 34 extending from the tip of the first tooth portion 32 to the side opposite the second tooth portion 33. In other words, the rib 34 is supported by the first tooth portion 32. The rib 34 covers a portion of the coil 4 inserted into the tooth 21 formed by the first tooth portion 32 supporting the rib 34 and the second tooth portion 33 of the adjacent segment 3.

[0023] The base of the rib 34 also covers the tip end surface of the second tooth portion 33. In this embodiment, the base of the rib 34 is inclined along the inclined portion 11b of the dividing line 11, and the portion of the rib 34 other than the base is arc-shaped with its center at the central axis 10 of the stator 1. The base of the rib 34, together with the first tooth portion 32 and the second tooth portion 33, constitutes the tooth 21. However, the length of the first tooth portion 32 may be increased so that the rib 34 is arc-shaped over its entire length so as to be bent 90 degrees from the first tooth portion 32.

[0024] In this embodiment, in a cross section perpendicular to the axial direction of the stator 1, the cross section of the covered portion 41 of each coil 4, which is the portion that contacts the second tooth portion 33 and is covered by the rib 34, and the cross section of the uncovered portion 42, which is the portion that contacts the first tooth portion 32, have the same area but different shapes. Here, "the same area" refers not only to the case where the areas of both are completely equal, but also to the case where they are substantially equal (for example, when the smaller area is 90% or more of the larger area).

[0025] Specifically, the cross section of the covered portion 41 is substantially rectangular. Meanwhile, the cross section of the non-covered portion 42 is trapezoidal, with the circumferential width around the central axis 10 of the stator 1 increasing toward the yoke portion 31. That is, the outer surface of the covered portion 41 is parallel to the side of the tooth 21 facing the second tooth portion 33, while the outer surface of the non-covered portion 42 is inclined relative to the side of the tooth 21 facing the first tooth portion 32. Because the cross section of the non-covered portion 42 is trapezoidal, the occupancy rate of the coil 4 in the fan-shaped slots formed between the teeth 21 can be improved.

[0026] In this embodiment, the length L of the rib 34 in the circumferential direction centered on the central axis 10 of the stator 1 is greater than the width C of the covering portion 41 on the rib 34 side. In this embodiment, because the cross-sectional shape of the covering portion 41 is substantially rectangular as described above, the width of the covering portion 41 on the rib 34 side is equal to the width on the yoke portion 31 side. Furthermore, in this embodiment, the gap G between the ribs 34 of adjacent segments 3 is smaller than the width D of the non-covering portion 42 on the yoke portion 31 side.

[0027] As described above, in the stator 1 of this embodiment, each segment 3 includes a rib 34 extending from the tip of the first tooth portion 32 to the opposite side of the second tooth portion 33, so that all coils 4 can be covered from the radial inside of the stator 1.

[0028] Furthermore, in this embodiment, in a cross section perpendicular to the axial direction of the stator 1, the cross sections of the covered portion 41 and the uncovered portion 42 of each coil 4 have the same area but different shapes, and the width A of the first tooth portion 32 is smaller than the width B of the second tooth portion 33. Therefore, when the air-core coil 4 is inserted into the teeth 21 to assemble the stator 1, the cross-sectional area of ​​the coil 4 can be increased. A larger cross-sectional area of ​​the coil 4 reduces the resistance of the coil 4, thereby improving motor efficiency. This effect can be achieved by either a configuration in which the cross sections of the covered portion 41 and the uncovered portion 42 of each coil 4 have the same area but different shapes in a cross section perpendicular to the axial direction of the stator 1, or a configuration in which the width A of the first tooth portion 32 is smaller than the width B of the second tooth portion 33.

[0029] Next, a method for assembling the stator 1 will be described. First, N air-core coils are prepared as the coils 4. The air-core coils 4, in which the cross section of the covered portion 41 and the cross section of the non-covered portion 42 are different as shown in Figure 2, can be formed by various methods. Next, as shown in Figures 3A to 3E, the coils 4 are inserted into the first tooth portions 32 of the N segments 3 to form N coil-holding segments 5.

[0030] 4, half of the coil holding segments 5 are connected together to form two stator halves 6. When connecting half of the coil holding segments 5 together, the coil 4 is brought into contact with the surface of the first tooth portion 32 on the second tooth portion 33 side of each coil holding segment 5, and the second tooth portion 33 of another coil holding segment 5 is inserted into a gap (see FIG. 3E) formed between the inner surface of the coil 4 and the surface of the first tooth portion 32 opposite the second tooth portion 33.

[0031] Finally, the two stator halves 6 are connected together. Specifically, the second tooth portion 33 of the coil holding segment 5 located at the other end of the two stator halves 6 (the upper end of the left stator half 6 and the lower end of the right stator half 6) is inserted into the gap between the inner surface of the coil 4 in the coil holding segment 5 located at one end of the two stator halves 6 (the upper end of the right stator half 6 and the lower end of the left stator half 6 in FIG. 4 ) and the surface of the first tooth portion 32 opposite the second tooth portion 33. Note that the assembled stator 1 is inserted into a cylindrical casing, thereby preventing the segments 3 from separating.

[0032] With this assembly method, the stator 1 can be assembled smoothly.

[0033] <Modifications> The present disclosure is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present disclosure.

[0034] For example, the teeth 21 do not necessarily have to be straight, but may be tapered toward the tip. In other words, the cross-sectional shape of each tooth 21 may be trapezoidal. In this case, the cross-sectional shapes of the covered portion 41 and the uncovered portion 42 of the coil 4 may both be rectangular.

[0035] Furthermore, it is not necessary to prepare an air-core coil for the coil 4 , and the coil 4 may be formed by winding a wire around the teeth 21 .

[0036] The length L of the rib 34 in the circumferential direction around the central axis 10 of the stator 1 may be equal to or smaller than the width C of the rib 34 side of the covering portion 41 of the coil 4. However, if the length L of the rib 34 is larger than the width C of the rib 34 side of the covering portion 41 of the coil 4, as in the above embodiment, the coil 4 can be held by the ribs 34 on both sides of one tooth 21, as shown in FIG.

[0037] The gap G between the ribs 34 of adjacent segments 3 may be larger than the width D of the non-covered portion 42 of the coil 4 on the yoke portion 31 side. However, if the gap G between the ribs 34 is smaller than the width D of the non-covered portion 42 on the yoke portion 31 side, as in the above embodiment, the amount of change in magnetic resistance of the ribs 34 can be reduced, thereby reducing the cogging torque.

[0038] <Summary> In a first aspect, the present disclosure provides a stator comprising, from one side, a stator core including N teeth (N is an even number) and N coils inserted into the teeth, wherein the stator core is divided into N segments along dividing lines passing through the teeth, and each segment includes an arc-shaped yoke portion, a first tooth portion and a second tooth portion protruding radially inward from both ends of the yoke portion, and a rib extending from the tip of the first tooth portion to the opposite side from the second tooth portion and covering a portion of the coil inserted into the tooth formed by the first tooth portion and the second tooth portion of an adjacent segment.

[0039] According to the above configuration, each segment includes a rib extending from the tip of the first tooth portion to the side opposite the second tooth portion, so that all coils can be covered from the radially inner side of the stator.

[0040] In a second aspect, in the first aspect, the teeth may be straight, and in a cross section taken orthogonal to the axial direction of the stator, the cross section of the non-covered portion of each coil that contacts the first tooth portion may have a trapezoidal shape whose circumferential width about the central axis of the stator increases toward the yoke portion. This configuration can improve the occupancy rate of the coil in the sector-shaped slots formed between the teeth.

[0041] As a third aspect, in the second aspect, in a cross section perpendicular to the axial direction of the stator, the cross section of the covered portion of each coil, which is the portion that contacts the second tooth portion and is covered by the rib, and the cross section of the uncovered portion may have the same area but different shapes. With this configuration, when assembling the stator by inserting an air-core coil into the teeth, the cross section of the coil can be increased. A larger cross section of the coil reduces the resistance value of the coil, thereby improving motor efficiency.

[0042] As a fourth aspect, in the second or third aspect, the distance between the ribs of adjacent segments may be smaller than the width of the non-covered portion on the yoke portion side, thereby reducing the amount of change in magnetic resistance of the ribs and thereby reducing cogging torque.

[0043] As a fifth aspect, in any of the second to fourth aspects, the length of the rib in the circumferential direction about the central axis of the stator may be greater than the width of the covering portion on the rib side. With this configuration, the coil can be held by the ribs on both sides of one tooth.

[0044] As a sixth aspect, in any of the first to fifth aspects, the teeth may be straight, and the width of the first tooth portion may be smaller than the width of the second tooth portion. With this configuration, when assembling a stator by inserting an air-core coil into the teeth, the cross-sectional area of ​​the coil can be increased. A larger cross-sectional area of ​​the coil reduces the resistance of the coil, thereby improving motor efficiency.

[0045] As a seventh aspect, from another aspect, the present disclosure provides a method for assembling a stator including a stator core including N teeth (N is an even number) and N coils inserted into the teeth, the method comprising: preparing air-core coils as the coils; dividing the stator core into N segments along dividing lines passing through the teeth; each segment including an arc-shaped yoke portion, a first tooth portion and a second tooth portion protruding radially inward from both ends of the yoke portion, and a rib extending from a tip of the first tooth portion to a side opposite the second tooth portion; inserting the coils into the first tooth portion of each segment to form N coil-holding segments; A method for assembling a stator is provided in which half of the coil holding segments are connected to form two stator halves by inserting the second tooth portion of another coil holding segment into a gap formed between the inner surface of the coil and the surface of the first tooth portion opposite the second tooth portion by bringing the coil in the segment into contact with the surface of the first tooth portion facing the second tooth portion, and the second tooth portion of the coil holding segment located at the other end of the two stator halves is inserted into the gap between the inner surface of the coil in the coil holding segment located at one end of the two stator halves and the surface of the first tooth portion opposite the second tooth portion.

[0046] According to the above configuration, the stator can be smoothly assembled.

[0047] REFERENCE SIGNS LIST 1 stator 10 central shaft 2 stator core 21 teeth 3 segment 31 yoke portion 32 first tooth portion 33 second tooth portion 34 rib 4 coil 41 coated portion 42 counter-coated portion 5 coil holding segment 6 stator half

Claims

1. A stator comprising: a stator core including N teeth (N is an even number); and N coils inserted into the teeth, wherein the stator core is divided into N segments along a dividing line passing through the teeth, and each segment includes an arc-shaped yoke portion, a first tooth portion and a second tooth portion protruding radially inward from both ends of the yoke portion, and a rib extending from the tip of the first tooth portion to the opposite side from the second tooth portion and covering a portion of the coil inserted into the tooth formed by the first tooth portion and the second tooth portion of an adjacent segment.

2. A stator as described in claim 1, wherein the teeth are straight, and in a cross section taken in a direction perpendicular to the axial direction of the stator, the cross section of the non-covered portion of each coil which is in contact with the first tooth portion is trapezoidal in shape with its circumferential width about the central axis of the stator increasing towards the yoke portion.

3. A stator as described in claim 2, wherein, in a cross section perpendicular to the axial direction of the stator, the cross section of the coated portion of each coil, which is in contact with the second tooth portion and covered by the rib, and the cross section of the non-coated portion have the same area but different shapes.

4. A stator as set forth in claim 2 or 3, wherein the distance between the ribs in adjacent segments is smaller than the width of the opposite side of the covering portion to the yoke portion.

5. A stator as set forth in claim 2 or 3, wherein the length of said ribs in the circumferential direction about the central axis of said stator is greater than the width of said covering portion on said rib side.

6. A stator as claimed in any one of claims 1 to 3, wherein said teeth are straight and the width of said first tooth portion is smaller than the width of said second tooth portion.

7. A method for assembling a stator having a stator core including N teeth (N is an even number) and N coils inserted into the teeth, comprising the steps of: preparing an air-core coil as the coil; dividing the stator core into N segments along a dividing line passing through the teeth, each segment including an arc-shaped yoke portion, a first tooth portion and a second tooth portion protruding radially inward from both ends of the yoke portion, and a rib extending from the tip of the first tooth portion to the side opposite the second tooth portion; inserting the coil into the first tooth portion of each segment to form N coil holding segments; bringing the coil into contact with the surface of the first tooth portion on the second tooth side in each coil holding segment to form a gap between the inner surface of the coil and the surface of the first tooth portion opposite the second tooth portion, thereby connecting half of the coil holding segments to form two stator halves; A method of assembling a stator, comprising: inserting a second tooth portion of a coil retaining segment located at the other end of the two stator halves into a gap between an inner surface of a coil in the coil retaining segment located at one end of the two stator halves and a surface of the first tooth portion opposite the second tooth portion, thereby connecting the two stator halves together.

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