JP2024058615A - Stator of rotary electric machine - Google Patents

Abstract

To suppress separation of slit mating surfaces due to spring back in a stator including a helical core stator core in which band steel plates are stacked on top of each other in a spiral shape.SOLUTION: A stator (10) of a rotary electric machine includes a helical stator core (11) in which band-shaped steel plates are spirally stacked to form a plurality of slots (23) opening on an inner circumference, a plurality of conductor segments (30) inserted into the slots and connected to each other to form a stator winding. The band-shaped steel plate has one slit each at a position corresponding to the plurality of slots, opening on the slot side. The conductor segments are formed in a U-shape, with both legs (31) inserted respectively into slots that are at least two slots away from each other.SELECTED DRAWING: Figure 5

Description

The present invention relates to a stator for a rotating electric machine.

Conventionally, there is a straight core that is constructed by stacking laminated plates having multiple teeth protruding from one long side of a band-shaped back yoke and V-shaped cutouts provided on the side where the teeth protrude between adjacent teeth on the back yoke (see Patent Document 1). The stator is formed into a ring shape by bending the straight core at the cutouts.

Patent No. 3681487

However, in the stator described in Patent Document 1, the bent straight core tends to return to its original shape due to springback, which causes the opposing inclined surfaces of the cutouts (slit mating surfaces) to move away from each other, which can cause the magnetic properties of the stator core to deteriorate.

The present invention was made to solve the above problems, and its main purpose is to suppress the separation of the slit mating surfaces due to springback in a stator having a helical core stator core in which strip-shaped steel plates are stacked in a spiral shape.

The first means for solving the above problem is to
A stator (10) for a rotating electric machine, comprising: a helical stator core (11) in which strip-shaped steel plates (20) are helically laminated and in which a plurality of slots (23) opening to the inner periphery side are formed; and a plurality of conductor segments (30) that are inserted into the slots and connected to each other to form a stator winding,
The strip-shaped steel plate has one or more slits (25) formed at positions corresponding to at least some of the plurality of slots so as to open toward the slots,
There is one or more locations where the two legs (31) of the conductor segment are connected across the slot corresponding to the slit.

According to the above configuration, the helical stator core is made of strip-shaped steel plates stacked in a spiral shape, and has multiple slots that open to the inner circumference. Multiple conductor segments are inserted into the slots and connected to each other to form the stator winding.

Here, the strip-shaped steel sheet has one or more slits formed at positions corresponding to at least some of the multiple slots so that they open toward the slots. Therefore, when the strip-shaped steel sheet is spirally stacked, the strip-shaped steel sheet can be easily deformed so that the opposing sides of the slits (hereinafter referred to as "slit mating surfaces") are brought closer together. However, springback, which causes the strip-shaped steel sheet to return to its original shape, can cause the slit mating surfaces to move apart from each other, which can degrade the magnetic properties of the helical stator core.

In this regard, there is one or more locations where the two legs (31) of the conductor segment are connected across the slot corresponding to the slit. Generally, when both legs of a conductor segment are inserted into a slot, the two legs apply a force to the stator core in a direction that brings them closer to each other. In addition, when one leg of one conductor segment is connected to one leg of the other conductor segment in two conductor segments, the legs apply a force to the stator core in a direction that brings them closer to each other. Therefore, in the slit corresponding to the slot between the two legs of the conductor segments, a force is applied that brings the slit mating surfaces closer to each other, and the separation of the slit mating surfaces due to springback can be suppressed.

The second means for solving the above problem is
A stator (10) for a rotating electric machine, comprising: a helical stator core (11) in which strip-shaped steel plates (20) are helically laminated and in which a plurality of slots (23) opening to the inner periphery side are formed; and a plurality of conductor segments (30) that are inserted into the slots and connected to each other to form a stator winding,
The strip-shaped steel plate has a slit (25) formed at each of the positions corresponding to the plurality of slots so as to open toward the slot,
The conductor segment is formed in a U-shape, and both legs (31) are inserted into the slots that are spaced apart from each other by two or more.

According to the above configuration, the helical stator core is made of strip-shaped steel plates stacked in a spiral shape, and has multiple slots that open to the inner circumference. Multiple conductor segments are inserted into the slots and connected to each other to form the stator winding.

Here, the strip-shaped steel sheet has one slit formed at each position corresponding to the multiple slots, opening toward the slot. Therefore, when stacking the strip-shaped steel sheet in a spiral shape, the strip-shaped steel sheet can be easily deformed so that the opposing sides of the slits (hereinafter referred to as "slit mating surfaces") are brought closer together. However, springback, which causes the strip-shaped steel sheet to return to its original shape, can cause the slit mating surfaces to move apart from each other, which can degrade the magnetic properties of the helical stator core.

In this regard, the conductor segment is formed in a U-shape, and both legs are inserted into the slots that are two or more apart from each other. Generally, when both legs of a conductor segment are inserted into the slots, the two legs apply a force to the stator core in a direction that brings them closer to each other. In addition, when one leg of one conductor segment is connected to one leg of the other conductor segment in two conductor segments, the legs apply a force to the stator core in a direction that brings them closer to each other. Therefore, in the slits corresponding to the slots between the two legs of the conductor segments, a force that brings the slit mating surfaces closer to each other acts, and the separation of the slit mating surfaces due to springback can be suppressed. Furthermore, there is always one or more slots between the two legs of all conductor segments. And since one slit is formed corresponding to one slot, all conductor segments can exert the effect of suppressing the separation of the slit mating surfaces.

In the third method, a recess is formed on one of the opposing side surfaces of the slit and a protrusion is formed on the other, and the recess and the protrusion are press-fitted together. With this configuration, the recess and the protrusion formed on the slit mating surface and press-fitted together can further suppress the separation of the slit mating surface.

In the fourth means, a first engagement portion is formed on one of the opposing side surfaces of the slit and a second engagement portion is formed on the other, and the first engagement portion and the second engagement portion are engaged with each other. With this configuration, the first engagement portion and the second engagement portion formed on the slit mating surface and engaged with each other can further suppress the separation of the slit mating surface.

In the fifth method, a notch is formed in the outer edge of the strip of steel sheet that corresponds to the end of the slit opposite the slot. With this configuration, it is possible to reduce the portion where stress remains when the strip of steel sheet is deformed and stacked in a spiral shape, and to reduce the amount of springback.

In the sixth means, the number of the slots and the slits is 48 or more. With this configuration, when the strip-shaped steel plate is stacked in a spiral shape, the amount of deformation of the strip-shaped steel plate at the positions corresponding to each slit can be reduced. This makes it possible to suppress the deterioration of the magnetic properties of the helical stator core, and to reduce the springback force that causes the strip-shaped steel plate to return to its original shape. Furthermore, since it becomes easier to increase the number of slots between both legs of one conductor segment, the separation of one or more slit mating surfaces corresponding to one slot can be suppressed by multiple conductor segments.

In the seventh aspect, based on the fifth aspect, the helical stator core includes a back yoke extending circumferentially around a central axis and teeth extending from the back yoke toward the central axis, and the ends of the slits opposite the slots are located in the outer radial direction of the teeth. With this configuration, when the magnetic flux flowing in the circumferential direction through the back yoke is blocked by a notch formed in the outer edge of the strip-shaped steel plate, the magnetic flux can be diverted to the outer radial portion of the teeth in the back yoke and allowed to flow in the circumferential direction. Therefore, it is possible to suppress the deterioration of the magnetic properties of the helical stator core due to magnetic saturation.

In the eighth means, the opposing side surfaces of the slits are formed in an arc shape. With this configuration, when the strip-shaped steel plate is spirally stacked, the shape difference of the slit mating surface due to manufacturing errors, etc., is easily absorbed by the slit mating surface being deformed so that the curvature of the slit mating surface formed in an arc shape changes. Therefore, it becomes easier to bring the slit mating surfaces into close contact over the entire surface, and the magnetic properties of the helical stator core can be improved.

In the ninth method, the radius of curvature of the side surface facing each other in the slit that will be stacked later in a spiral shape is greater than the radius of curvature of the side surface that will be stacked later in a spiral shape first. With this configuration, the side surface that will be stacked later in a spiral shape can be deformed to imitate the side surface that will be stacked earlier in a spiral shape, making it easier to bring the slit mating surfaces into close contact over the entire surface. This can improve the magnetic properties of the helical stator core.

When the helical stator core is formed in a polygonal column shape, residual stress due to tensile deformation of the strip-shaped steel plate tends to concentrate at the corners of the polygonal column-shaped helical stator core. For this reason, the magnetic properties of the corners of the polygonal column-shaped helical stator core tend to deteriorate more than the magnetic properties of other parts.

In this regard, in the tenth aspect, the helical stator core is formed in a polygonal column shape, and a case is press-fitted to the outer periphery of the helical stator core. With this configuration, the corners of the polygonal column-shaped helical stator core are compressed by the case, and residual stress due to tensile deformation of the strip-shaped steel plate can be alleviated. Therefore, the magnetic properties of the helical stator core can be improved.

In the eleventh means, the radial positions of the outer circumferential surfaces of the spirally stacked band-shaped steel plates are offset from each other in the stacking direction. With this configuration, the area of the outer surface of the helical stator core can be increased, and the heat dissipation of the helical stator core can be improved.

In the twelfth means, a notch (28) is formed in the outer edge (20b) of the strip-shaped steel plate that is off the extension line of the end (25b) of the slit opposite the slot in the outer diameter direction of the helical stator core. With this configuration, it is possible to reduce the portion (outer edge) where stress remains when the strip-shaped steel plate is deformed and stacked in a spiral shape, and the amount of springback can be reduced. Furthermore, a notch is formed in the strip-shaped steel plate in a portion that is off the extension line of the longitudinal direction (extension direction) of the slit. Therefore, compared to the case where a notch is formed on the longitudinal extension line of the slit, it is possible to suppress a crack starting from the notch reaching the slit and causing the steel plate to break.

In the thirteenth means, a convex portion (29) protruding in the outer diameter direction of the helical stator core is formed on the outer edge portion (20a) of the strip-shaped steel plate corresponding to the end portion (25b) of the slit opposite the slot. With this configuration, the width of the outer edge portion in the outer diameter direction of the helical stator core can be expanded, and stress concentration on the outer edge portion due to bending (deformation) of the steel plate can be alleviated. Therefore, breakage of the outer edge portion due to stress concentration on the outer edge portion can be suppressed. Furthermore, when the outer edge portion is stretched in the circumferential direction of the helical stator core, a decrease in the width of the outer edge portion in the radial direction of the helical stator core can be suppressed.

In the fourteenth means, the strip-shaped steel plate is formed with circumferential slits (40) that extend from the end of the slit opposite the slot to both sides in the circumferential direction of the helical stator core. With this configuration, the range in which stress is concentrated due to bending of the steel plate can be expanded from the outer edge of the strip-shaped steel plate corresponding to the end of the slit opposite the slot to the length range of the circumferential slit in the circumferential direction of the helical stator core. This makes it possible to reduce the average stress in the range in which stress is concentrated. Therefore, it is possible to suppress breakage of the outer edge due to stress concentration on the outer edge.

In the fifteenth means, a circular hole (25b) is formed in the end of the slit opposite the slot in the band-shaped steel plate, and a small circular hole (25ba) smaller than the circular hole is formed so as to connect to a portion of the circular hole that is apart from the end opposite the slot. With this configuration, the range in which stress is concentrated due to bending of the steel plate can be expanded from the outer edge portion to the range of the small circular hole in the circumferential direction of the stator core. Therefore, it is possible to suppress breakage of the outer edge portion due to stress concentration on the outer edge portion.

FIG. FIG. FIG. 4 is a plan view showing a manner in which strip-shaped steel plates are stacked. An enlarged partial view of a strip of steel plate. FIG. 4 is a perspective view showing a manner in which a plurality of conductor segments are inserted into a helical stator core. FIG. 4 is a perspective view showing a conductor segment and a part of a stator core. FIG. 13 illustrates some conductor segments received within slots. An enlarged partial view of a steel strip being bent. 1 is a graph showing the relationship between residual stress and iron loss. FIG. 11 is a partially enlarged view showing a modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 15 is a partially enlarged view showing the function and effect of the strip-shaped steel plate of FIG. 14 . FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 13 is a schematic diagram showing a modified example of the stator core. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate. FIG. 11 is a partially enlarged view showing another modified example of the strip-shaped steel plate.

Below, an embodiment of the present invention, which is embodied in a stator of a rotating electric machine mounted on a vehicle (e.g., a hybrid vehicle or an electric vehicle), will be described with reference to the drawings. Note that in the following embodiments and modified examples, parts that are identical or equivalent to each other are given the same reference numerals in the drawings, and the explanations of the parts with the same reference numerals are used. The rotating electric machine is, for example, an electric motor (motor), a generator, or a motor generator (MG).

The rotating electric machine of this embodiment is applicable to permanent magnet synchronous motors, wound field type motors, and induction motors, and is a rotating electric machine with three-phase windings. The rotating electric machine includes a cylindrical stator 10 (fixed part) shown in FIG. 1, a rotor (not shown) arranged radially inside the stator 10, and the like. The rotor (rotor) is arranged to be rotatable around a rotation axis with respect to the stator 10. Hereinafter, the axial direction refers to the axial direction of the stator 10, i.e., the axial direction of the rotor's rotation axis, the radial direction refers to the radial direction of the stator 10, i.e., the direction passing through the center of the rotor's rotation axis and perpendicular to the rotation axis, and the circumferential direction refers to the circumferential direction of the stator 10, i.e., the direction of rotation around the rotor's rotation axis.

1 and 2, the stator 10 includes a stator core 11 (helical stator core) having an annular shape, and a stator winding 12 wound around the stator core 11. The rotating electric machine of this embodiment is an inner rotor type rotating electric machine, and the rotor is arranged in a rotatable state on the radial inside of the stator 10. The stator winding 12 is a three-phase winding having a U-phase winding, a V-phase winding, and a W-phase winding as phase windings for each phase, and a power line bus bar 13 is connected to one end of each phase winding, and a neutral line bus bar 14 is connected to the other end. In the stator winding 12, the area that overlaps with the stator core 11 in the axial direction is the in-slot coil portion CS, and the portions that are axially outside the stator core 11 on both axial sides are the coil end portions CE1 and CE2.

The case 15 is shrink-fitted (pressurized) onto the outer periphery of the stator core 11. More specifically, the case 15 is formed into a cylindrical shape from metal. The case 15 is heated and expanded to fit the stator core 11, which has an outer diameter slightly larger than the inner diameter of the case 15, and then cooled to fix the two together. The case 15 is formed with an escape groove or the like to allow the power line bus bar 13 to escape. Alternatively, the power line bus bar 13 can be positioned so that it does not interfere with the case 15.

As shown in FIG. 3, the stator core 11 is formed by stacking strip-shaped steel sheets 20 in a spiral shape. The strip-shaped steel sheets 20 are formed, for example, from electromagnetic steel sheets, which are magnetic materials. The strip-shaped steel sheets 20 extend in a straight line before being bent into a spiral shape. The stator core 11 is formed in a 48-sided prism shape (polygonal prism shape).

The stator core 11 has a circular back yoke 21 and a plurality of teeth 22 that protrude radially inward from the back yoke 21 and are arranged at a predetermined distance in the circumferential direction, and a slot 23 is formed between adjacent teeth 22. The slots 23 have an opening shape that extends radially and are provided at equal intervals in the circumferential direction in the stator core 11. In the stator core 11, the number of slots 23 is 48 (48 or more). The slots 23 open on the inner peripheral side of the stator core 11. The stator winding 12 is provided in a state of being wound around the slots 23. In the stator core 11 molded into a 48-sided prism, one slit 25 (more specifically, a series of slits 25 overlapping in the axial direction) is formed corresponding to one slot 23. That is, in the stator core 11 molded into a 48-sided prism, 48 (48 or more) slits 25 are formed at equal intervals in the circumferential direction.

Figure 4 is a partially enlarged view of the strip-shaped steel plate 20. Figure 4(a) shows the state of the strip-shaped steel plate 20 before it is bent into a spiral shape, and Figure 4(b) shows the state of the strip-shaped steel plate 20 after it has been bent into a spiral shape. Note that the relationship between (a) and (b) remains the same in Figures 10 and onward.

In the strip-shaped steel plate 20, one slit 25 is formed at each position corresponding to the 48 (plural) slots 23, so that each slit 25 opens toward the slot 23. In the state shown in FIG. 4(a), the slits 25 are formed in a V-shape that spreads from a predetermined position in the radial direction of the stator core 11 to the inner diameter side in the back yoke 21. The opposing side surfaces 25a of the slits 25 (hereinafter also referred to as "slit mating surfaces 25a") are formed in a flat shape. A circular hole 25b (hole) is formed in the end (base) of the slit 25 on the opposite side (outer diameter side) to the slot 23.

As shown in FIG. 4(b), when bending the strip-shaped steel plate 20 into a spiral shape, the strip-shaped steel plate 20 is deformed so that the slit mating surfaces 25a approach each other with the circular hole 25b as the fulcrum. The slit mating surfaces 25a are then brought into contact with each other or brought into close proximity. If the slit mating surfaces 25a move away from each other due to springback, which causes the strip-shaped steel plate 20 to return to its original shape, the magnetic properties of the stator core 11 will be reduced. In addition, in the strip-shaped steel plate 20, the bending deformation amount of the outer edge portion 26 extending from the circular hole 25b (the deformation fulcrum) in the outer diameter direction of the stator core 11 is larger than the bending deformation amount of other parts. In the back yoke 21, tensile stress remains in the outer edge portion 26.

Figure 5 is a perspective view showing how multiple conductor segments 30 are inserted into the stator core 11. The multiple conductor segments 30 are arranged in a predetermined order and inserted into the corresponding slots 23 from the axial direction of the stator core 11.

The stator winding 12 is configured by connecting three-phase windings in a Y-connection (star-shaped connection). The stator winding 12 generates magnetic flux when power (AC power) is supplied from a power source via an inverter (not shown). The stator winding 12 is configured by connecting together a number of conductor segments 30, which are divided conductors formed into a roughly U-shape from an electrical conductor of a constant thickness with a roughly rectangular cross section (flat cross section). The segment structure of the stator winding 12 will be described in detail below.

6 is a perspective view showing a conductor segment 30 and a part of the stator core 11. The conductor segment 30 has a U-shape (approximately U-shape) and has a pair of straight parts 31 that are straight and a turn part 32 that is bent so as to connect the pair of straight parts 31. The pair of straight parts 31 (both legs of the conductor segment 30) has a length longer than the axial thickness of the stator core 11. The conductor segment 30 is composed of a flat conductor wire in which a conductor (a conductor having a pair of opposing flat parts) with a rectangular cross section is covered with an insulating coating, and the tip of each straight part 31 is a conductor exposed part 33 where the conductor is exposed by removing the insulating coating. The conductor segment 30 may be a continuum (for example, a wave shape) in which multiple folded shapes such as a U-shape are connected, or a shape in which multiple single straight parts 31 (straight conductors) are connected. The connected conductor segments 30 may include joints formed by welding or the like, or may be formed as a continuous piece without any breaks.

A plurality of conductor segments 30 are inserted into the slots 23 of the stator core 11 in a radially aligned state. In this embodiment, the straight portions 31 of the conductor segments 30 are accommodated in the slots 23 in a state of being stacked in four layers (multiple layers). In the conductor segment 30, a pair of straight portions 31 is accommodated in two slots 23 that are two or more apart from each other (a predetermined coil pitch apart). The two slots 23 that are two or more apart from each other do not refer to two adjacent slots 23, but rather to two slots 23 with one or more slots 23 sandwiched between them. As the two slots 23 that are two or more apart from each other to accommodate the pair of straight portions 31, for example, two slots 23 that are 3 to 6 apart from each other (4 to 7 slots apart) can be used. The portion of the straight portion 31 accommodated in the slot 23 corresponds to the in-slot coil portion CS of the stator winding 12. An insulating sheet 24 that electrically insulates the stator core 11 and the stator winding 12 (conductor segment 30) is provided in the slot 23. The insulating sheet 24 is folded so as to surround the multiple conductor segments 30 inserted into the slots 23, and is sandwiched between the inner peripheral surface (inner wall surface) of the stator core 11 and the conductor segments 30 within the slots 23.

The pair of straight sections 31 of the conductor segment 30 are accommodated in the two slots 23, each shifted by one radial position. For example, when one straight section 31 is accommodated in the nth position from the radial back side (back yoke side), the other straight section 31 is accommodated in the n+1th position from the radial back side.

When each conductor segment 30 is inserted into the slot 23 of the stator core 11, the straight portion 31 of each conductor segment 30 is inserted from the first end side of the first end side and the second end side of the axial ends of the stator core 11, and the tip portion of the straight portion 31 protrudes from the second end side. In this case, at the first end side of the stator core 11, one coil end portion CE1 is formed by the turn portion 32 of the conductor segment 30. At the second end side of the stator core 11, the anti-turn portion side of each straight portion 31 is bent in the circumferential direction, and the straight portions 31 of different conductor segments 30 are connected to each other to form the other coil end portion CE2. The outline of each coil end portion CE1, CE2 is as shown in FIG. 2. Next, the connection of the conductor segments 30 at the coil end portion CE2 will be described in more detail. Here, the connection between the conductor segments 30 will be described first.

Figure 7 shows some of the conductor segments 30 housed in the slots 23. In Figure 7, the stator core 11 is shown by imaginary lines. In the conductor segments 30, the anti-turn sides of a pair of straight portions 31 protrude from the axial end face (the upper end face in the figure) of the stator core 11 and are bent in the circumferential direction so as to be oblique at a predetermined angle with respect to the core end face. The exposed conductor portions 33 at the tips of different conductor segments 30 are joined together, for example by welding, so that multiple conductor segments 30 are connected to each other.

At the coil end portion CE2, the circumferential tip of one conductor segment 30 that extends in a fixed circumferential direction on the axial outside of the stator core 11 is joined to the circumferential tip of another conductor segment 30 that extends in the opposite direction to the fixed circumferential direction. As a result, at the coil end portion CE2 of the stator winding 12, the straight portions 31 of the conductor segments 30 extend in a direction that is inclined with respect to the axial direction and are folded back at a predetermined apex position. In this state, the joined straight portions 31 apply a force to the stator core 11 in a direction that brings them closer to each other. The conductor segments 30 include those in which the anti-turn side of each straight portion 31 is bent in the circumferential direction to the same side as the turn portion 32, and those in which the anti-turn side of each straight portion 31 is bent in the circumferential direction to the opposite side to the turn portion 32.

In the phase windings of each phase, the conductors are connected in the middle by joining the conductor segments 30 together, while at the ends of the windings, the power line busbars 13 and neutral line busbars 14 of each phase are connected to the exposed conductor portions 33.

Figure 8 is a partially enlarged view of the strip-shaped steel plate 20 in a bent state. The dashed-dotted lines show the positions where stress remains, with the residual stress at the position corresponding to point P being greater than in other areas. Because the stator core 11 is formed in a 48-sided prism (polygonal prism), the residual stress due to tensile deformation of the strip-shaped steel plate 20 is concentrated at the corners (outer edge portions 26) of the stator core 11.

Figure 9 is a graph showing the relationship between residual stress and iron loss. As shown in the graph, the iron loss increases as the residual tensile stress increases. When bending the strip-shaped steel plate 20 into a spiral shape, the tensile stress at the outer edge 26 of the stator core 11 increases, as indicated by arrow A1. As a result, the iron loss increases to L1. Then, by shrink-fitting the case 15 onto the outer periphery of the stator core 11, the tensile stress decreases due to the compressive load, as indicated by arrow A2. As a result, the iron loss decreases to L2.

The present embodiment described above has the following advantages:

- The strip-shaped steel plate 20 has one slit 25 formed at each position corresponding to the multiple slots 23, opening toward the slot 23. Therefore, when the strip-shaped steel plate 20 is spirally stacked, the strip-shaped steel plate 20 can be easily deformed so that the opposing sides of the slits 25 (slit mating surfaces 25a) are brought closer together.

The conductor segment 30 is formed in a U-shape, and a pair of straight portions 31 (both legs) are inserted into slots 23 that are two or more apart from each other. When the pair of straight portions 31 of the conductor segment 30 are inserted into the slots 23, the pair of straight portions 31 apply a force to the stator core 11 in a direction that brings them closer to each other. In addition, when the straight portion 31 (one leg) of one conductor segment 30 is connected to the straight portion 31 of the other conductor segment 30 in two conductor segments 30, the straight portions 31 apply a force to the stator core 11 in a direction that brings them closer to each other. Therefore, in the slits 25 corresponding to the slots 23 between the pair of straight portions 31 of the conductor segment 30, a force that brings the slit mating surfaces 25a closer to each other acts, and the separation of the slit mating surfaces 25a due to springback can be suppressed. Regardless of the shape or connection state of the conductor segment 30, the straight portions 31 of any of the conductor segments 30 described above correspond to the legs of the conductor segment 30.

- At least one slot 23 is always present between a pair of straight sections 31 of every conductor segment 30. And since one slit 25 is formed corresponding to one slot 23, every conductor segment 30 can exert the effect of suppressing the separation of the slit mating surfaces 25a.

- In the stator core 11 formed from the strip-shaped steel plate 20, the number of slots 23 and slits 25 (a series of slits 25 overlapping in the axial direction) is 48 (48 or more). With this configuration, when the strip-shaped steel plate 20 is spirally stacked, the amount of deformation of the strip-shaped steel plate 20 at the positions corresponding to each slit 25 can be reduced. Therefore, it is possible to suppress the deterioration of the magnetic properties of the stator core 11, and to reduce the springback force that causes the strip-shaped steel plate 20 to return to its original shape. Furthermore, since it is easier to increase the number of slots 23 present between a pair of straight portions 31 of one conductor segment 30, the separation of one slit mating surface 25a corresponding to one slot 23 can be suppressed by multiple conductor segments 30.

The stator core 11 is formed in a 48-sided prism (polygonal prism), and the case 15 is shrink-fitted (pressure-fitted) to the outer periphery of the stator core 11. With this configuration, the corners of the 48-sided prism-shaped stator core 11 are compressed by the case 15, and residual stress due to tensile deformation of the strip-shaped steel plate 20 can be alleviated. Therefore, the magnetic properties of the stator core 11 can be improved.

The above embodiment can be modified as follows. The same parts as those in the above embodiment are designated by the same reference numerals and will not be described.

- As shown in FIG. 10(a), a recess 25c may be formed on one of the opposing side surfaces 25a (slit mating surface 25a) of the slit 25, and a protrusion 25d may be formed on the other. Then, as shown in FIG. 10(b), the recess 25c and the protrusion 25d may be press-fitted together. With this configuration, the recess 25c and the protrusion 25d formed on the slit mating surface 25a and press-fitted together can further suppress the separation of the slit mating surface 25a.

・As shown in FIG. 11(a) showing a part of the slit mating surface 25a, a plurality of recesses 25c may be formed on one side of the slit mating surface 25a, and a plurality of protrusions 25d may be formed on the other side. As shown in FIG. 11(b), the plurality of recesses 25c and the plurality of protrusions 25d may be fitted together. With this configuration, the contact area between the plurality of recesses 25c and the plurality of protrusions 25d can be increased to increase the frictional force between the plurality of recesses 25c and the plurality of protrusions 25d, and the separation of the slit mating surface 25a can be further suppressed. As shown in FIG. 12, the shapes of the recesses 25c and the protrusions 25d can be arc-shaped (round) or other shapes such as a trapezoid. Also, as shown in FIG. 13, the plurality of recesses 25c may have different shapes, and the plurality of protrusions 25d may have different shapes corresponding to them.

- As shown in FIG. 14, the outer diameter α (width) of the multiple convex portions 25d may be larger than the interval β (width) of the entrances (openings) of the multiple concave portions 25c. Even with such a configuration, the contact area between the multiple concave portions 25c and the multiple convex portions 25d can be increased, thereby increasing the frictional force between the multiple concave portions 25c and the multiple convex portions 25d, and the separation of the slit mating surface 25a can be further suppressed. Furthermore, as shown in FIG. 15, the multiple concave portions 25c and the multiple convex portions 25d are continuously formed without any intervals, so that when the slit mating surface 25a tries to separate, adjacent protrusions (protrusions between the convex portions 25d and the concave portions 25c) can apply a reaction force to each other. Therefore, the separation of the slit mating surface 25a can be further suppressed. Also, as shown in FIG. 16, holes 25da can be formed in the multiple protrusions (protrusions between the convex portions 25d and the concave portions 25c) to make the multiple protrusions easier to elastically deform.

- As shown in FIG. 17(a), a circular notch 25e (first engagement portion) may be formed on one of the opposing side surfaces 25a (slit mating surface 25a) of the slit 25, and a circular protrusion 25f (second engagement portion) may be formed on the other. As shown in FIG. 17(b), the notch 25e and the protrusion 25f may be fitted together (engaged). With this configuration, the notch 25e and the protrusion 25f formed in and fitted to the slit mating surface 25a can further suppress the separation of the slit mating surface 25a.

- As shown in FIG. 18(a), an acute-angled notch 25e (first engagement portion) may be formed on one of the opposing side surfaces 25a (slit mating surface 25a) of the slit 25, and a protrusion 25f (second engagement portion) having an R portion (rounded portion) may be formed on the other. As shown in FIG. 18(b), the notch 25e and the protrusion 25f may be fitted (engaged). With this configuration, the notch 25e and the protrusion 25f formed in and fitted to the slit mating surface 25a can further suppress the separation of the slit mating surface 25a.

・As shown in FIG. 19(a), a triangular notch 25e (first engagement portion) may be formed near one side of the opposing side surfaces 25a (slit mating surfaces 25a) of the slit 25, and a claw-shaped protrusion 25f (second engagement portion) may be formed near the other side. Then, as shown in FIG. 19(b), the notch 25e and the protrusion 25f may be engaged (engaged). With this configuration, the notch 25e and the protrusion 25f formed near the slit mating surface 25a and engaged therewith can further suppress the separation of the slit mating surface 25a. In addition, as shown in FIG. 20, a taper 25ea that widens toward the outside may be formed at the opening of the notch 25e, and an R portion 25fa (round portion) may be formed at the tip of the protrusion 25f. With this configuration, when the notch 25e and the protrusion 25f are engaged with each other, the taper 25ea and the R portion 25fa can slide easily, making it easier to insert the protrusion 25f into the notch 25e. Similarly, a notch 25e (first engagement portion) and a protrusion 25f (second engagement portion) of the shape shown in FIG. 21 can be used. A taper 25ea that widens toward the outside is formed at the opening of the notch 25e, and an R portion 25fa (rounded portion) is formed at the tip of the protrusion 25f.

- As shown in FIG. 22, the notch 25e (first engagement portion) may have a multi-stage corner portion 25eb, and the protrusion 25f (second engagement portion) may have a multi-stage claw portion 25fb. This configuration makes it difficult for the protrusion 25f to come out of the notch 25e, and further suppresses the separation of the slit mating surface 25a.

As shown in FIG. 23(a), tapers 25ec approaching each other toward the opening end (outside) may be formed at the opening of the notch 25e, a rounded portion 25fa (rounded portion) may be formed at the tip of the protrusion 25f, and a hole 25fc may be formed in the protrusion 25f. With this configuration, when the notch 25e and the protrusion 25f are engaged, the end of the taper 25ec and the rounded portion 25fa are more likely to slide, and the protrusion 25f is more likely to elastically deform, making it easier to insert the protrusion 25f into the notch 25e. In addition, the tapers 25ec approaching each other toward the opening end make it more difficult for the protrusion 25f to come out of the notch 25e, and further suppress the separation of the slit mating surface 25a.

- As shown in FIG. 24(a), a circular notch 25e (first engagement portion) may be formed on one of the opposing side surfaces 25a (slit mating surface 25a) of the slit 25, and a rectangular (rectangular) protrusion 25f (second engagement portion) having a width narrower than the opening width of the notch 25e may be formed on the other side. Then, as shown in FIG. 24(b), the protrusion 25f may be inserted into the notch 25e and crushed (crimped), thereby deforming the protrusion 25f so that the width of the protrusion 25f is wider than the opening width of the notch 25e, as shown in FIG. 24(c). With this configuration, the notch 25e formed in the slit mating surface 25a and the protrusion 25f deformed after insertion can further suppress the separation of the slit mating surface 25a.

- As shown in FIG. 25, a notch 27 may be formed in the outer edge 20a of the strip-shaped steel plate 20 corresponding to the end (circular hole 25b) of the slit 25 opposite the slot 23. The notch 27 is formed in a V-shape or U-shape. With this configuration, it is possible to reduce the portion (outer edge 20a) where stress remains when the strip-shaped steel plate 20 is deformed and stacked in a spiral shape, and the amount of springback can be reduced.

- As shown in FIG. 26, the end (circular hole 25b) of the slit 25 opposite the slot 23 may be located in the outer diameter direction of the tooth 22, as shown by the dashed arrow. That is, the end of the slit 25 opposite the slot 23 may be offset from the outer diameter direction of the slot 23. The end (opening) of the slit 25 on the same side as the slot 23 is located in the outer diameter direction of the slot 23. With this configuration, when the magnetic flux flowing in the circumferential direction of the back yoke 21 is blocked by the notch 27 or the circular hole 25b formed in the outer edge portion 20a of the strip-shaped steel plate 20, the magnetic flux can be diverted to the outer diameter portion of the tooth 22 in the back yoke 21 and flow in the circumferential direction. Therefore, it is possible to suppress the deterioration of the magnetic characteristics of the stator core 11 due to magnetic saturation.

- As shown in FIG. 27, the opposing side surfaces 25a of the slit 25 may be formed in an arc shape. Here, the opposing side surfaces 25a have the same radius of curvature. With this configuration, when the strip-shaped steel plate 20 is spirally stacked, the shape difference of the slit mating surface 25a due to manufacturing errors, etc., is easily absorbed by the slit mating surface 25a deforming so that the curvature of the slit mating surface 25a formed in an arc shape changes. Therefore, it becomes easier to bring the slit mating surfaces 25a into close contact with each other over the entire surface, and the magnetic characteristics of the stator core 11 can be improved.

- As shown in FIG. 28, the radius of curvature of the side surface 25a2 that will be stacked later in a spiral shape may be larger than the radius of curvature of the side surface 25a1 that will be stacked later in a spiral shape on the opposing side surfaces 25a1 and 25a2 (slit mating surfaces) of the slit 25. With this configuration, the side surface 25a2 that will be stacked later in a spiral shape can be deformed to imitate the side surface 25a1 that will be stacked earlier in a spiral shape, making it easier to bring the slit mating surfaces 25a1 and 25a2 into close contact over the entire surface. This improves the magnetic properties of the stator core 11.

- Figure 29 is a schematic diagram showing a modified example of the stator core 11. Figure 29 (b) shows an enlarged view of the R portion of Figure 29 (a). The radial direction D1 positions of the outer peripheral surfaces S1, S2, S3 of the spirally laminated band-shaped steel plate 20 may be offset from each other in the lamination direction D2. With this configuration, the area of the outer surface of the stator core 11 can be increased, and the heat dissipation of the stator core 11 can be improved. Note that in the above configuration, the stator core 11 and the case can be fastened by bolts or screws, etc., rather than shrink-fitting (pressure-fitting) the case 15 to the outer periphery of the stator core 11.

30, a notch 28 may be formed in the outer edge 20b of the strip-shaped steel plate 20 that is off the extension line of the end (circular hole 25b) of the slit 25 opposite the slot 23 in the outer diameter direction of the stator core 11. The notch 28 is formed in a V-shape, a U-shape, a trapezoidal shape, or a rectangular shape. With this configuration, the portion (outer edge 26, 20b) where stress remains when the strip-shaped steel plate 20 is deformed and stacked in a spiral shape can be reduced, and the amount of springback can be reduced. Furthermore, the notch 28 is formed in the strip-shaped steel plate 20 in a portion that is off the extension line of the longitudinal direction (extension direction) of the slit 25. Therefore, compared to the case where the notch 27 is formed on the longitudinal extension line of the slit 25 as shown in FIG. 25, it is possible to suppress a crack starting from the notch 27 from reaching the slit 25 and causing the steel plate 20 to break.

・As shown in FIG. 31, a convex portion 29 protruding in the outer diameter direction of the stator core 11 may be formed on the outer edge portion 20a of the strip-shaped steel plate corresponding to the end (circular hole 25b) of the slit 25 opposite the slot 23. The convex portion 29 is formed in a semi-elliptical or rectangular shape. With this configuration, the width of the outer edge portion 26 in the outer diameter direction of the stator core 11 can be expanded, and stress concentration on the outer edge portion 26 due to bending of the steel plate 20 can be alleviated. Therefore, breakage of the outer edge portion 26 due to stress concentration on the outer edge portion 26 can be suppressed. Furthermore, when the outer edge portion 26 is stretched in the circumferential direction of the stator core 11, a decrease in the width of the outer edge portion 26 in the radial direction of the stator core 11 can be suppressed. The outer edge portion 26 is a portion of the steel plate 20 that extends in the outer diameter direction of the stator core 11 from the end (circular hole 25b) of the slit 25 opposite the slot 23.

- As shown in FIG. 32, the band-shaped steel plate 20 may have circumferential slits 40 formed therein, which extend from the end of the slit 25 opposite the slot 23 to both sides in the circumferential direction of the stator core 11. The circumferential slits 40 are formed in an oval, elliptical, rectangular, or inverted triangular shape. With this configuration, the range in which stress is concentrated due to bending of the steel plate 20 can be expanded from the outer edge 26 to the length of the circumferential slit 40 in the circumferential direction of the stator core 11. This makes it possible to reduce the average stress in the range in which stress is concentrated. This makes it possible to suppress breakage of the outer edge 26 due to stress concentration on the outer edge 26.

- As shown in FIG. 33, in the band-shaped steel plate 20, a circular hole 25b is formed at the end of the slit 25 opposite the slot 23, and a small circular hole 25ba smaller than the circular hole 25b may be formed so as to connect to the part of the circular hole 25b that is off the end opposite the slot 23. The small circular hole 25ba is formed in any size smaller than the circular hole 25b, and is formed in multiple or single numbers. The multiple small circular holes 25ba may be different in size from each other. With this configuration, the range in which stress is concentrated by bending the steel plate 20 can be expanded from the outer edge portion 26 to the range of the small circular hole 25ba in the circumferential direction of the stator core 11. Therefore, it is possible to suppress breakage of the outer edge portion 26 due to stress concentration on the outer edge portion 26.

- As shown in FIG. 34, the notch 28 in FIG. 30 and the protrusion 29 in FIG. 31 can be combined. With this configuration, the effects of the notch 28 and the protrusion 29 can be achieved.

- As shown in FIG. 35, the notch 28 in FIG. 30 and the circumferential slit 40 in FIG. 32 can be combined. With this configuration, the effects of the notch 28 and the circumferential slit 40 can be achieved.

- As shown in FIG. 36, it is also possible to combine the convex portion 29 in FIG. 31 with the circumferential slit 40 in FIG. 32. With this configuration, it is possible to obtain the effects of the convex portion 29 and the effects of the circumferential slit 40.

- As shown in FIG. 37, it is also possible to combine the notch 28 in FIG. 30, the convex portion 29 in FIG. 31, and the circumferential slit 40 in FIG. 32. With this configuration, it is possible to obtain the effects of the notch 28, the convex portion 29, and the circumferential slit 40.

- The notch 28 in FIG. 30 can be combined with the circular hole 25b and small circular hole 25ba in FIG. 33. This configuration provides the effects of the notch 28 as well as the circular hole 25b and small circular hole 25ba.

- The convex portion 29 in FIG. 31 can be combined with the circular hole 25b and the small circular hole 25ba in FIG. 33. This configuration can achieve the effects of the convex portion 29 as well as the effects of the circular hole 25b and the small circular hole 25ba.

- It is also possible to combine the notch 28 in FIG. 30, the convex portion 29 in FIG. 31, and the circular hole 25b and small circular hole 25ba in FIG. 33. With this configuration, it is possible to achieve the effects of the notch 28, the convex portion 29, and the circular hole 25b and small circular hole 25ba.

- As shown in FIG. 38, the strip-shaped steel plate 20 may be formed with two (one or more) slits 25 at positions corresponding to the slots 23, opening toward the slots 23. Such a configuration can be applied to the above-mentioned embodiment and each modified example. With the above configuration, a force acts to bring the slit mating surfaces 25a closer to each other in the slits 25 corresponding to the slots 23 between the two straight portions 31 of the conductor segment 30, and separation of the slit mating surfaces 25a due to springback can be suppressed.

- As shown in FIG. 39, the strip-shaped steel plate 20 may be formed with one slit 25 opening toward the slot 23 at a position corresponding to a portion (at least a portion) of the multiple slots 23. Such a configuration can be applied to the above-mentioned embodiment and each modified example. With the above configuration, a force acts to bring the slit mating surfaces 25a closer to each other in the slits 25 corresponding to the slots 23 between the two straight portions 31 of the conductor segment 30, and separation of the slit mating surfaces 25a due to springback can be suppressed.

- As shown in FIG. 40, the strip-shaped steel plate 20 may be formed with two (one or more) slits 25 at positions corresponding to a portion (at least a portion) of the multiple slots 23, opening toward the slot 23 side. Such a configuration can be applied to the above-mentioned embodiment and each modified example. With the above configuration, a force acts to bring the slit mating surfaces 25a closer to each other in the slits 25 corresponding to the slots 23 between the two straight portions 31 of the conductor segment 30, and separation of the slit mating surfaces 25a due to springback can be suppressed.

The above modifications can also be implemented in combination.

Characteristic configurations extracted from the above-described embodiment and modified examples will be described below.
[Configuration 1]
A stator (10) for a rotating electric machine, comprising: a helical stator core (11) in which strip-shaped steel plates (20) are helically laminated and in which a plurality of slots (23) opening to the inner periphery side are formed; and a plurality of conductor segments (30) that are inserted into the slots and connected to each other to form a stator winding,
The strip-shaped steel plate has one or more slits (25) formed at positions corresponding to at least some of the plurality of slots so as to open toward the slots,
A stator for a rotating electric machine, wherein there is at least one location where two legs (31) of the conductor segment are connected across the slot corresponding to the slit.
[Configuration 2]
A stator (10) for a rotating electric machine, comprising: a helical stator core (11) in which a strip-shaped steel plate (20) is spirally laminated and in which a plurality of slots (23) opening to the inner periphery side are formed; and a plurality of conductor segments (30) that are inserted into the slots and connected to each other to form a stator winding,
The strip-shaped steel plate has a slit (25) formed at each of the positions corresponding to the plurality of slots so as to open toward the slot,
The conductor segment is formed in a U-shape, and both legs (31) are inserted into the slots that are spaced apart from each other by two or more.
[Configuration 3]
3. The stator of a rotating electric machine according to configuration 1 or 2, wherein a recess (25c) is formed on one of the opposing side surfaces (25a) of the slit and a protrusion (25d) is formed on the other, and the recess and the protrusion are press-fitted together.
[Configuration 4]
A stator for a rotating electric machine according to any one of configurations 1 to 3, wherein a first engagement portion (25e) is formed on one of the opposing side surfaces of the slit and a second engagement portion (25f) is formed on the other of the opposing side surfaces of the slit, and the first engagement portion and the second engagement portion are engaged with each other.
[Configuration 5]
A stator for a rotating electric machine according to any one of configurations 1 to 4, wherein a notch (27) is formed in an outer edge portion (20a) of the strip-shaped steel plate corresponding to an end portion (25b) of the slit opposite the slot.
[Configuration 6]
6. The stator of a rotating electric machine according to any one of configurations 1 to 5, wherein the number of the slots and the number of the slits are each 48 or more.
[Configuration 7]
The helical stator core includes a back yoke (21) extending in a circumferential direction about a central axis, and teeth (22) extending from the back yoke toward the central axis,
6. The stator of a rotating electric machine according to claim 5, wherein an end (25b) of the slit opposite to the slot is positioned in an outer radial direction of the teeth.
[Configuration 8]
8. The stator of a rotating electric machine according to any one of configurations 1 to 7, wherein the opposing side surfaces (25a, 25a1, 25a2) of the slits are formed into arcuate surfaces.
[Configuration 9]
A stator for a rotating electric machine according to configuration 8, wherein, on the opposing side surfaces of the slit, a radius of curvature of a side surface (25a2) that will be stacked later in a spiral shape is larger than a radius of curvature of a side surface (25a1) that will be stacked first in a spiral shape.
[Configuration 10]
The helical stator core is formed in a polygonal column shape,
10. The stator of a rotating electric machine according to any one of configurations 1 to 9, wherein a case (15) is press-fitted onto an outer periphery of the helical stator core.
[Configuration 11]
11. The stator of a rotating electric machine according to any one of configurations 1 to 10, wherein the radial positions of the outer circumferential surfaces of the band-shaped steel plates stacked in a spiral shape are shifted from each other in the stacking direction.
[Configuration 12]
A stator for a rotating electric machine according to any one of configurations 1 to 11, wherein a notch (28) is formed in an outer edge portion (20b) of the strip-shaped steel plate that deviates from an extension line of an end portion (25b) of the slit opposite the slot in the outer radial direction of the helical stator core.
[Configuration 13]
13. The stator of a rotating electric machine according to any one of configurations 1 to 12, wherein a convex portion (29) protruding in the outer diameter direction of the helical stator core is formed on an outer edge portion (20a) of the strip-shaped steel plate corresponding to an end portion (25b) of the slit opposite to the slot.
[Configuration 14]
The stator of a rotating electric machine according to any one of configurations 1 to 13, wherein the strip-shaped steel plate has a circumferential slit (40) formed therein, the slit extending from an end of the slit opposite the slot to both sides in the circumferential direction of the helical stator core.
[Configuration 15]
A stator for a rotating electric machine according to any one of configurations 1 to 13, wherein a circular hole (25b) is formed in the strip-shaped steel plate at an end of the slit opposite the slot, and a small circular hole (25ba) smaller than the circular hole is formed so as to connect to a portion of the circular hole that is off the end opposite the slot.

10... stator, 11... stator core, 12... stator winding, 20... strip-shaped steel plate, 23... slot, 25... slit, 30... conductor segment.

Claims (15)

A stator (10) for a rotating electric machine, comprising: a helical stator core (11) in which strip-shaped steel plates (20) are helically laminated and in which a plurality of slots (23) opening to the inner periphery side are formed; and a plurality of conductor segments (30) that are inserted into the slots and connected to each other to form a stator winding,
The strip-shaped steel plate has one or more slits (25) formed at positions corresponding to at least some of the plurality of slots so as to open toward the slots,
A stator for a rotating electric machine, wherein there is at least one location where two legs (31) of the conductor segment are connected across the slot corresponding to the slit. A stator (10) for a rotating electric machine, comprising: a helical stator core (11) in which strip-shaped steel plates (20) are helically laminated and in which a plurality of slots (23) opening to the inner periphery side are formed; and a plurality of conductor segments (30) that are inserted into the slots and connected to each other to form a stator winding,
The strip-shaped steel plate has a slit (25) formed at each of the positions corresponding to the plurality of slots so as to open toward the slot,
The conductor segment is formed in a U-shape, and both legs (31) are inserted into the slots that are spaced apart from each other by two or more. The stator of a rotating electric machine according to claim 1 or 2, in which a recess (25c) is formed on one of the opposing side surfaces (25a) of the slit and a protrusion (25d) is formed on the other, and the recess and the protrusion are press-fitted together. The stator of a rotating electric machine according to claim 1 or 2, in which a first engagement portion (25e) is formed on one of the opposing side surfaces of the slit and a second engagement portion (25f) is formed on the other, and the first engagement portion and the second engagement portion are engaged with each other. The stator of a rotating electric machine according to claim 1 or 2, wherein a notch (27) is formed in the outer edge (20a) of the strip-shaped steel plate corresponding to the end (25b) of the slit opposite the slot. The stator of a rotating electric machine according to claim 1 or 2, wherein the number of the slots and the number of the slits are 48 or more. The helical stator core includes a back yoke (21) extending in a circumferential direction about a central axis, and teeth (22) extending from the back yoke toward the central axis,
6. The stator for a rotating electric machine according to claim 5, wherein an end (25b) of each of the slits opposite to the slot is positioned in an outer radial direction of each of the teeth. The stator of a rotating electric machine according to claim 1 or 2, wherein the opposing side surfaces (25a, 25a1, 25a2) of the slits are formed in an arc shape. The stator of a rotating electric machine according to claim 8, wherein the radius of curvature of the side surface (25a2) that will be stacked later in a spiral shape is larger than the radius of curvature of the side surface (25a1) that will be stacked later in a spiral shape on the opposing side surfaces of the slit. The helical stator core is formed in a polygonal column shape,
3. The stator of claim 1, wherein a case (15) is press-fitted onto an outer periphery of the helical stator core. The stator of a rotating electric machine according to claim 1 or 2, wherein the radial positions of the outer circumferential surfaces of the spirally stacked band-shaped steel plates are offset from each other in the stacking direction. The stator of a rotating electric machine according to claim 1 or 2, wherein a notch (28) is formed in the outer edge (20b) of the strip-shaped steel plate that is off the extension line of the end (25b) of the slit opposite the slot in the outer diameter direction of the helical stator core. The stator of a rotating electric machine according to claim 1 or 2, wherein a protrusion (29) protruding in the outer diameter direction of the helical stator core is formed on the outer edge (20a) of the strip-shaped steel plate corresponding to the end (25b) of the slit opposite the slot. The stator of a rotating electric machine according to claim 1 or 2, wherein the strip-shaped steel plate has circumferential slits (40) formed therein, the slits extending from the ends of the slits opposite the slots to both sides in the circumferential direction of the helical stator core. The stator of a rotating electric machine according to claim 1 or 2, wherein a circular hole (25b) is formed at the end of the slit opposite the slot in the strip-shaped steel plate, and a small circular hole (25ba) smaller than the circular hole is formed so as to connect to a portion of the circular hole that is apart from the end opposite the slot.

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