Stator core for rotating electrical machine

Abstract

The stator core (11) has an annular back yoke (21) and a plurality of teeth (22) protruding from the back yoke (21) in the radial direction. The stator core is configured by laminating core pieces (30) in a plurality of layers. The core piece (30) has protrusions (34) which are provided at predetermined intervals in the circumferential direction, have a bent shape protruding in the lamination direction, and extend in the radial direction, and the protrusions (34) are laminated in a state of overlapping each other in the lamination direction. The plate thickness dimensions of the convex parts (34) and the flat parts (35) between the convex parts (34) adjacent in the circumferential direction are different, and the plate thickness dimensions of the convex parts (34) are smaller than the plate thickness dimensions of the flat parts (35).

Description

Technical Field

[0001] The invention relates to a stator core of a rotating electric machine. Background Art

[0002] As a stator core of a rotating electric machine, a structure in which iron core sheets made of steel plate materials are stacked in multiple layers is known. In addition, the following technology is known: when manufacturing the stator core, a bending portion in the form of a triangular mountain or the like is formed at a predetermined interval along the circumferential direction on the iron core sheet in a strip shape, and the iron core sheet is bent by the bending portion (for example, refer to Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-217279

[0006] However, in a structure in which a triangular mountain-shaped bend is formed on the core sheet and the bends overlap each other, since the steel sheet material in the bend is inclined relative to the stacking direction (i.e., the stator axial direction), the thickness in the stacking direction becomes locally thicker in the stator core. Therefore, gaps are unintentionally generated in the stator core at locations other than the bends. In this case, in a structure in which the core sheet is fixed by riveting or welding, there is a concern that the strength of the stator core may be insufficient or the performance of the rotating electrical machine may be reduced. Summary of the invention

[0007] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a stator core of a rotating electric machine capable of suppressing the formation of unintentional gaps between core sheets in a stacked state.

[0008] The present invention relates to a stator core of a rotating electric machine, the stator core having an annular back yoke and a plurality of teeth radially protruding from the back yoke, the stator core being formed by laminating iron core sheets in multiple layers, wherein:

[0009] The core sheet has convex portions, which are arranged at predetermined intervals in the circumferential direction, are in a bent shape convex in the stacking direction, and extend in the radial direction, and the convex portions are stacked in a state of overlapping each other in the stacking direction.

[0010] The convex portion and a flat portion between the convex portions adjacent to each other in the circumferential direction have different plate thicknesses, and the plate thickness of the convex portion is smaller than the plate thickness of the flat portion.

[0011] In a stator core formed by stacking iron sheets in multiple layers, convex portions are provided at predetermined intervals along the circumferential direction on the iron sheets, and the convex portions are in a bent shape protruding in the stacking direction and extending in the radial direction, and the iron sheets are stacked in a state where the convex portions overlap each other in the stacking direction. In this case, the iron sheets are bent into an arc shape by the convex portions, thereby preferably forming a circular annular back yoke. In addition, in the iron sheets, the plate thickness dimensions of the convex portions and the flat portions between the convex portions adjacent in the circumferential direction are different, and the plate thickness dimensions of the convex portions are smaller than the plate thickness dimensions of the flat portions. Thus, even if the steel sheet material in the convex portions is inclined relative to the stacking direction (i.e., the stator axial direction), the difference in thickness between the steel sheet material of the convex portions and the flat portions in the stacking direction becomes smaller. As a result, it is possible to suppress the formation of unintentional gaps between the iron sheets in the stacked state in the stator core, thereby eliminating problems such as insufficient strength of the stator core. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a three-dimensional diagram of the stator.

[0013] Figure 2 This is the front view of the stator.

[0014] Figure 3 It is a top view of the stator core.

[0015] Figure 4 This is a diagram showing an enlarged portion of a core piece.

[0016] Figure 5 The figure shows the manufacturing process of the stator core.

[0017] Figure 6 It is a longitudinal cross-sectional view of the iron core sheet.

[0018] Figure 7 It is a diagram showing an iron core sheet.

[0019] Figure 8 It is a diagram showing an iron core sheet.

[0020] Fig. 9 It is a diagram showing a core sheet in Modification Example 1.

[0021] Fig.10 It is a diagram showing a core sheet in Modification Example 1.

[0022] Fig.11 This is a longitudinal sectional view showing a state where the stator winding is assembled to the stator core in Modification 1.

[0023] Fig.12 This is a longitudinal sectional view showing a state where a stator winding is assembled to a stator core in Modification 2.

[0024] Fig.13It is a diagram showing a core sheet in Modification Example 2.

[0025] Fig.14 It is a diagram showing an iron core sheet in Modification Example 3.

[0026] Fig.15 It is a diagram showing a core sheet according to a second embodiment.

[0027] Fig.16 It is a diagram showing a core sheet according to a second embodiment.

[0028] Fig.17 It is a diagram showing another example of a core piece. DETAILED DESCRIPTION

[0029] (First Embodiment)

[0030] Hereinafter, an embodiment embodied in a stator of a rotating electrical machine mounted on a vehicle (e.g., a hybrid vehicle or an electric vehicle) will be described with reference to the accompanying drawings. In addition, in the following embodiments and modifications, the same or equivalent parts are marked with the same reference numerals in the drawings, and the descriptions of the parts with the same reference numerals are cited. The rotating electrical machine is, for example, an electric motor (motor), a generator, or an MG (Motor Generator).

[0031] The rotating electrical machine of this embodiment is a permanent magnet synchronous motor, which can be applied to a winding excitation type and an induction machine, and is a rotating electrical machine having a three-phase winding. Figure 1 The cylindrical stator 10 (stator) shown in the figure, the rotor (rotor) not shown arranged on the radial inner side of the stator 10, etc. The rotor is rotatably arranged with respect to the stator 10 with the rotation axis as the center. Hereinafter, the axial direction refers to the axial direction of the stator 10, that is, the axial direction of the rotation axis of the rotor, the radial direction refers to the radial direction of the stator 10, that is, the direction passing through the center of the rotation axis of the rotor and orthogonal to the rotation axis, and the circumferential direction refers to the circumferential direction of the stator 10, that is, the circumferential direction with the rotation axis of the rotor as the center.

[0032] like Figure 1 and Figure 2As shown, the stator 10 includes a stator core 11 in an annular shape and a multi-phase stator winding 12 wound on the stator core 11. The rotating electric machine of the present embodiment is an inner rotor type rotating electric machine, and the rotor is arranged radially inside the stator 10 in a rotatable state. 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 of each phase, and one end of the phase winding of each phase is connected to the power line bus bar 13, and the other end is connected to the neutral line bus bar 14. In the stator winding 12, the range that overlaps with the stator core 11 in the axial direction is the coil side CS, and the portion on both axial sides that is axially outside of the stator core 11 is the coil end CE.

[0033] Figure 3 1 is a top view of the stator core 11. The stator core 11 is formed by stacking the core pieces 30 made of steel plate material (electromagnetic steel plate) into multiple layers in the axial direction and fixing them by riveting, welding, bonding, etc. In the present embodiment, the stator core 11 is a spiral stator core structure formed by spirally stacking the strip-shaped core pieces 30. By making the stator core 11 a spiral stator core structure, it is possible to improve the material yield, save materials, and reduce costs.

[0034] The stator core 11 has an annular back yoke 21 and a plurality of teeth 22 protruding radially inward from the back yoke 21 and arranged at a predetermined distance in the circumferential direction, and slots 23 are formed between adjacent teeth 22. The slots 23 are open in a shape extending with the radial direction as the long side, and are arranged at equal intervals in the circumferential direction in the stator core 11. The slots 23 are open on the inner circumferential side of the stator core 11.

[0035] like Figure 1 As shown, the stator winding 12 is wound in each slot 23 at a predetermined slot pitch. The stator winding 12 uses, for example, an insulating covered conductor in which the conductor is covered by an insulating layer, and the conductor is contained in each slot 23 in multiple layers in the radial direction. In the present embodiment, the stator winding 12 is a segmented structure, and the stator winding 12 is formed by joining a plurality of conductor segments 15 formed into a substantially U shape. In the stator winding 12, a coil end CE on one axial side is formed by a turn portion of each conductor segment 15, and a coil end CE on the other axial side is formed by connecting the ends (straight portions) of different conductor segments 15 to each other. The stator winding 12 generates magnetic flux by supplying power to each phase via an inverter not shown.

[0036] In the present embodiment, the core sheet 30 is bent into an arc shape by providing the convex portions 34 extending in the radial direction at predetermined intervals in the circumferential direction. This will be described in detail below.

[0037] Figure 43 is an enlarged view showing a portion of the core sheet 30, wherein (a) is a top view of the core sheet 30, and (b) is a cross-sectional view taken along line 4B-4B of (a). Figure 4 As shown in (a), the core sheet 30 generally has a long strip-shaped yoke forming portion 31 as a portion for forming the back yoke 21 and a tooth forming portion 32 as a portion for forming the teeth 22. By stacking the core sheets 30, the yoke forming portion 31 overlaps in the axial direction to form the back yoke 21, and the tooth forming portion 32 overlaps in the axial direction to form the teeth 22. That is, in the stator core 11, the portion corresponding to the yoke forming portion 31 of the core sheet 30 is the back yoke 21, and the portion corresponding to the tooth forming portion 32 is the teeth 22. In the core sheet 30, the slot recesses 33 for slot formation are formed between the tooth forming portions 32 arranged in the circumferential direction.

[0038] The yoke forming portion 31 is provided with a convex portion 34 that is bent and protrudes in the stacking direction and extends in the radial direction. The convex portion 34 is a component that protrudes a large height on the radial inner side and a small height on the radial outer side of the yoke forming portion 31, and has a generally triangular shape whose width becomes narrower toward the radial outer side when viewed from above. The convex portion 34 is provided at a position that becomes the radial outer side of each groove recess 33. Thus, the convex portions 34 are provided at predetermined intervals in the circumferential direction (see Figure 4 (b)). In addition, in the yoke forming portion 31, a flat portion 35 is formed between the convex portions 34 adjacent to each other in the circumferential direction. In addition, the flat portion 35 and the tooth forming portion 32 of the yoke forming portion 31 are both flat and are provided in a continuous manner in the radial direction.

[0039] By providing the convex portions 34 at predetermined intervals on the yoke forming portion 31, the circumferential length of the radial inner side of the yoke forming portion 31 is shorter than the circumferential length of the radial outer side when viewed from above, and the core sheet 30 is bent in a substantially arc shape. Furthermore, in the stator core 11, when the core sheets 30 are stacked in multiple layers, the convex portions 34 and the flat portions 35 overlap in the stacking direction. In this case, if the concave side of the convex portion 34 is set as the inner concave portion 36, the core sheets 30 are stacked in such a manner that the convex portion 34 on the lower layer side enters the inner concave portion 36 of the convex portion 34 on the upper layer side.

[0040] Figure 5 1 is a diagram showing the manufacturing process of the stator core 11. Figure 5 In FIG. 1 , a portion indicated by X1 shows a state before the core piece 30 is spirally bent, and a portion on the front side of X1 shows a state after the core piece 30 is spirally bent.

[0041] The core sheet 30 is formed into a predetermined flat plate shape by, for example, stamping of a steel sheet material before bending, the yoke forming portion 31 is in a straight band shape, and the tooth forming portion 32 is formed at predetermined intervals in a manner extending from the yoke forming portion 31 in a direction perpendicular to the long side direction of the yoke forming portion 31. In addition, at the stage before bending, the opposing portions in the groove recess 33 that are opposite to each other in the long side direction of the yoke are substantially V-shaped, which expands as they approach the tooth tip side.

[0042] Then, a bending device (not shown) is used to make the cylindrical stator core 11 while the core piece 30 is bent spirally by bending the yoke forming portion 31. That is, the core piece 30 is bent roughly in the shape of an arc by bending the protrusion 34 at a predetermined interval in the yoke forming portion 31. At this time, the protrusion 34 is formed in a manner that is wide on the radial inner side and narrow on the radial outer side when viewed from above, thereby making the circumferential length inside and outside the radial direction different, and the core piece 30 is bent roughly in the shape of an arc. After the bending, in the groove recess 33, the opposing portions that are opposite to each other in the long side direction of the yoke are parallel to each other.

[0043] The spirally formed core sheets 30 are stacked in multiple layers with the protrusions 34 overlapping each other in the stacking direction. Thus, a cylindrical stator core 11 is manufactured. Then, in the stator core 11, the flat portion 35 is fixed in the axial direction by caulking, welding, bonding, or the like.

[0044] However, in the structure where the core sheet 30 is provided with the convex portion 34, if the plate thickness dimensions of the steel plate material in the convex portion 34 and the flat portion 35 are the same, the thickness in the stacking direction (i.e., the stator axial direction) of the convex portion 34 is thicker than the plate thickness dimension of the flat portion 35. Therefore, in the stacked state of the core sheet 30, gaps are generated between the flat portions 35, and there is a concern that the strength of the stator core 11 is insufficient and the performance of the rotating electrical machine is reduced.

[0045] Therefore, in the present embodiment, in the core piece 30, the plate thickness dimensions of the convex portion 34 and the flat portion 35 are made different, and the structure is as follows: Figure 6 As shown in (a). Figure 6 In (a), the plate thickness dimension of the flat portion 35 is set to T1, and the plate thickness dimension of the convex portion 34 is set to T2, and the relationship between these T1 and T2 is T1>T2. In addition, the plate thickness dimensions T1 and T2 are dimensions corresponding to the wall thickness in the direction perpendicular to the plate surface in the steel plate material constituting the core sheet 30.

[0046] In this case, the plate thickness dimension T2 of the convex portion 34 is smaller than the plate thickness dimension T1 of the flat portion 35. Figure 6In the lamination state of the core sheets shown in (b), the formation of gaps between the flat portions 35 is suppressed, and the flat portions 35 are in contact with each other. In addition, it is preferred that the thickness T3 of the convex portion 34 in the lamination direction is the same as the plate thickness T1 of the flat portion 35 (i.e., T1=T3). In this case, the flat portions 35 are in contact with each other and the convex portions 34 are in contact with each other in the lamination direction.

[0047] The relationship between the plate thickness T1 of the flat portion 35 and the thickness T3 of the convex portion 34 in the stacking direction may be T1>T3 instead of T1=T3. Even with this structure, it is possible to suppress the formation of gaps between the flat portions 35 when the core sheets 30 are stacked.

[0048] In addition, in the present embodiment, the protrusion 34 is provided in the range from the radial innermost side to the radial outermost side of the yoke forming portion 31, that is, in the radial entire region of the yoke forming portion 31, and is formed in a manner protruding from the flat portion 35 in the radial entire region of the yoke forming portion 31. In other words, the protrusion 34 is formed so as to protrude from the flat portion 35 even in the radial outermost portion of the yoke forming portion 31, that is, in the portion where the protrusion height of the protrusion 34 is the smallest.

[0049] Here, in the core sheet 30, when the protruding height of the convex portion 34 is zero at the radially outermost side of the yoke forming portion 31, the convex portion 34 changes from protruding height zero to protruding in the axial direction in the radial direction in which the convex portion 34 extends. In this case, at the beginning of the convex portion 34, the steel plate material is bent and formed and thinned, and it is difficult to form the convex portion 34. In this regard, as described above, the convex portion 34 is formed to protrude from the flat portion 35 even at the radially outermost portion of the yoke forming portion 31, that is, the portion where the protruding height of the convex portion 34 is the smallest, so that it is easy to bend the steel plate material and thin it to form the convex portion 34.

[0050] Figure 6 (c) shows a side view of the core piece 30 viewed from the radially outer side of the yoke forming portion 31. Figure 6 As shown in (c), at the radially outermost portion of the convex portion 34, the depth dimension T4 of the inner concave portion 36 is greater than the plate thickness dimension T1 of the flat portion 35. The depth dimension T4 of the inner concave portion 36 may be equal to the plate thickness dimension T1 of the flat portion 35.

[0051] When the stator core 11 is manufactured, the convex portion 34 is formed on the core sheet 30 by a bending device, and when the core sheet 30 is bent, the convex portion 34 is formed by bending the steel plate material at the convex portion forming position of the yoke forming portion 31 while thinning the steel plate material by pressurizing and rolling. For example, a pressurizing fixture that clamps the core sheet 30 in the thickness direction can be used, and the thickness of the thin-walled portion can be adjusted while thinning the steel plate material by pressurizing the pressurizing fixture. In addition, the bending device can also be a device that performs the bending and thinning of the steel plate material as simultaneous processes, or a device that performs the bending and thinning of the steel plate material as different processes, such as a device that thins the steel plate material after bending it, or a device that thins the steel plate material before bending it. In short, the bending device can be any device that completes the bending and thinning of the steel plate material before stacking the core sheet 30.

[0052] In the core piece 30 of the present embodiment, in addition to the bending of the steel plate material, thinning may also be considered, and a bending region before bending may be determined in the steel plate material. That is, when thinning the steel plate material, since the steel plate material elongates in the long side direction, the elongation may be considered, and the range of the bending region may be set smaller.

[0053] However, when the core piece 30 is bent by the protrusions 34 arranged at predetermined intervals along the circumferential direction, the yoke forming portion 31 becomes a polygonal shape, and the back yoke 21 is formed into a polygonal cylindrical shape by the polygonal yoke forming portion 31. In addition, in a rotating electric machine, it is conceivable to assemble the stator core 11 in a fitted state on the inner circumference of a cylindrical shell. In this case, the stator core 11 and the shell are in a state of contact at multiple points on the outer circumference of the stator core 11, and in the stator core 11, there is a concern that the fitting pressure is concentrated at the contact portion in contact with the shell, and the fixing force is reduced with deformation near the contact portion. In addition, by applying a locally high fitting stress to the stator core 11, there is a concern that the iron loss of the core is increased due to the residual stress, and the efficiency of the motor is reduced.

[0054] Therefore, in the present embodiment, in the core sheet 30, the outer peripheral edge of the yoke forming portion 31 (i.e., the radial edge on the opposite side to the tooth forming portion 32) is partially rolled, and the portion between the convex portions 34 in the circumferential direction is formed into a circular shape when viewed from above. Figure 7As shown in (a) and (b), a rolled portion 41 extending in the circumferential direction is provided on the outer peripheral edge of the yoke forming portion 31. In this case, the annular forming of the stator core 11 is achieved by providing the convex portion 34 on the core sheet 30, and the outer peripheral surface of the stator core 11 can be prevented from becoming a polygonal shape by partially rolling the outer peripheral edge of the yoke forming portion 31. In this embodiment, since the core sheet 30 is partially rolled, the increase in the core iron loss caused by rolling can be suppressed.

[0055] In addition, if Figure 8 As shown, the rolled portion 41 may be provided at a position other than the protrusion 34 in the outer peripheral portion of the back yoke 21. In this case, by discontinuously providing the rolled portion 41 in the yoke forming portion 31 avoiding the protrusion 34, deformation of the outer peripheral portion caused by the flatness of the protrusion 34 can be suppressed.

[0056] According to the present embodiment described in detail above, the following excellent effects can be obtained.

[0057] In the core sheet 30, the plate thickness dimensions T1 and T2 of the convex portion 34 and the flat portion 35 are different, and the plate thickness dimension T2 of the convex portion 34 is smaller than the plate thickness dimension T1 of the flat portion 35. Thus, even if the steel plate material in the convex portion 34 is inclined with respect to the stacking direction (i.e., the stator axial direction), the difference in thickness between the steel plate material of the convex portion 34 and the flat portion 35 in the stacking direction is reduced. As a result, it is possible to suppress the formation of unintentional gaps between the core sheets 30 stacked in the stator core 11.

[0058] In this case, riveting, welding, bonding, etc. between the core pieces 30 can be performed without problems, and the strength reduction of the stator core 11 can be suppressed. In addition, in the stator core 11, the torque output reduction caused by the reduction of the space factor of the magnetic material and the increase of the volume caused by the gap can be suppressed. Furthermore, in the stator core 11, by closely contacting the core pieces 30 in the stacking direction, the heat resistance is reduced, the heat dissipation is improved, and high output can be exerted.

[0059] The protrusion 34 of the core sheet 30 has a large protrusion height on the radially inner side and a small protrusion height on the radially outer side in the yoke forming portion 31, and is formed to protrude from the flat portion 35 even at the radially outermost portion of the yoke forming portion 31 (i.e., the portion where the protrusion height of the protrusion 34 is the smallest). In this case, in the core sheet 30, compared with a structure in which the protrusion height of the radially outermost protrusion 34 at the yoke forming portion 31 is zero, it is easier to bend and form the steel sheet material and thin the wall to form the protrusion 34, and the protrusion 34 caused by the thinning of the steel sheet material can be appropriately formed.

[0060] At the radially outermost portion of the convex portion 34 , the depth dimension T4 of the inner concave portion 36 is equal to or greater than the plate thickness dimension T1 of the flat portion 35 . This allows the core sheets 30 to be joined more appropriately over the entire radial range of the yoke forming portion 31 .

[0061] The rolled portion 41 is provided at the outer peripheral edge of the yoke forming portion 31 of the core sheet 30, and the portion between the convex portions 34 in the circumferential direction is formed into an arc shape when viewed from above by the rolled portion 41. In this case, by providing the convex portions 34 in the core sheet 30, the annular forming of the stator core 11 can be achieved, and by partially rolling the outer peripheral edge of the yoke forming portion 31, the outer peripheral surface of the stator core 11 can be prevented from becoming a polygonal shape.

[0062] Furthermore, if the rolled portion 41 is provided at a location other than the protrusion 34 in the yoke forming portion 31 of the core piece 30 , deformation of the outer peripheral edge of the yoke forming portion 31 caused by the protrusion 34 being flattened can be suppressed.

[0063] Modifications of the first embodiment are described below.

[0064] (Variant 1)

[0065] exist Fig. 9 and Fig.10 In the structure shown, the convex portion 34 is formed into a trapezoidal shape, and the upper bottom portion 37 as the top is parallel to the flat portion 35. In this case, as shown in FIG. Fig. 9 As shown, in the convex portion 34, the top portion is flattened within a predetermined radial range including the radial innermost side (the groove concave portion 33 side), thereby forming the upper bottom portion 37.

[0066] like Fig.10 As shown, in the convex portion 34, the plate thickness dimension T11 of the upper bottom portion 37 is larger than the plate thickness dimension T12 of the inclined portion. In addition, the plate thickness dimension T11 of the upper bottom portion 37 may be the same as the plate thickness dimension T1 of the flat portion 35. However, the plate thickness dimension T11 of the upper bottom portion 37 may be the same as the plate thickness dimension T12 of the inclined portion, or may be smaller than the plate thickness dimension T1 of the flat portion 35.

[0067] Fig.11 1 is a longitudinal sectional view showing a state where the stator winding 12 is assembled in the stator core 11. Fig.11As shown, the stator winding 12 is accommodated in the slot 23 of the stator core 11. The stator winding 12 is composed of a plurality of conductor segments 15 arranged in a radial direction. Each conductor segment 15 is arranged in a radially close position in the slot 23 (coil side CS), and is arranged in a radially separated state outside the slot 23 (coil end CE). In this case, in the coil end CE, since the conductor segment 15 (stator winding 12) is bent to the side opposite to the rotor air gap, that is, the radially outer side, in the stator core 11, when the protrusion 34 protrudes axially, there is a concern about interference between the protrusion 34 and the conductor segment 15. In this regard, by forming the protrusion 34 into a trapezoidal shape as described above, the top portion becomes the upper bottom portion 37, so that the interference between the protrusion 34 and the conductor segment 15 is suppressed.

[0068] In addition, by making the protrusion 34 into a trapezoidal shape, the coil end height of the stator winding 12 can be reduced, thereby achieving the effect of miniaturizing the rotating motor. Compared with the case where the protrusion 34 is triangular in shape, the magnetic path length of the protrusion 34 is shortened, and the torque output can be improved by reducing the magnetic resistance.

[0069] (Variant 2)

[0070] like Fig.12 As shown, the core pieces 30 of one or more layers at the axial end of the stator core 11 may be structured such that at least the top portion is cut out of the convex portion 34. In this case, the convex portion 34 of the core piece 30 at the axial end of the stator core 11 may be cut out on the top side along a line orthogonal to the axial direction. In the stator core 11, the core pieces 30 with the top side of the convex portion 34 cut out may be stacked in the axial end, and the core pieces 30 with the top side of the convex portion 34 not cut out may be stacked outside the axial end. Fig.13 1 shows the core piece 30 used at the axial end of the stator core 11. In the core piece 30, the core pieces 30 other than the axial end (see Figure 4 ) is different from the embodiment in that the notch portion 38 is formed by cutting off the top side of the protrusion 34.

[0071] according to Fig.12 , Fig.13 The stator core 11 has a shorter axial length by partially cutting off the convex portion 34, so that the core mass can be increased without increasing the axial length of the stator core 11. As a result, the magnetic path width is expanded and the torque output is improved.

[0072] (Variant 3)

[0073] In the core sheet 30 , the angle of the triangular top of the protrusion 34 may be different between the radially inner side and the radially outer side of the yoke forming portion 31 . Fig.14The figures show that the convex portion shapes of the convex portion 34 of the core sheet 30 are different in the radial direction inside and outside, (a) shows the convex portion shape on the radial inner side, and (b) shows the convex portion shape on the radial outer side.

[0074] like Fig.14 As shown in (a) and (b), the protruding height of the convex portion 34 is different on the radial inside and radial outside of the convex portion 34, and the angle of the triangular top is different. In this case, if the angle of the triangular top on the radial inside is set to θ1, and the angle of the triangular top on the radial outside is set to θ2, the relationship between these θ1 and θ2 is θ1<θ2. In addition, the plate thickness dimensions of the convex portion 34 are different on the radial inside and radial outside. In this case, if the plate thickness dimension of the convex portion 34 on the radial inside is set to T21, and the plate thickness dimension of the convex portion 34 on the radial outside is set to T22, the relationship between these T21 and T22 is T21<T22. In addition, the plate thickness dimension of the flat portion 35 is the same at any point inside or outside the radial direction (is T23).

[0075] In the convex portion 34 of the core sheet 30, by making the angle of the triangular top different in the radial direction inside and outside the yoke forming portion 31 (back yoke 21), the circumferential length can be made different on the inner and outer sides of the yoke forming portion 31, and the yoke forming portion 31 can be bent and formed. In addition, in the convex portion 34, the angle of the triangular top is larger and the plate thickness is larger on the radial outer side of the yoke forming portion 31 than on the radial inner side of the yoke forming portion 31. As a result, on the radial outer side where the protruding height of the convex portion 34 is smaller, the inclination angle relative to the flat portion 35 becomes smaller, and the increase in the axial thickness of the stator caused by the inclination becomes smaller. Therefore, on the radial outer side where the bending size becomes smaller, the degree of thinning of the steel plate material can be reduced, and the thinning of the steel plate material can be appropriately performed.

[0076] (Second Embodiment)

[0077] In this embodiment, the structure for making the plate thickness dimensions of the convex portion 34 and the flat portion 35 different in the core sheet 30 is different from that in the first embodiment. Here, the core sheet 30 is respectively made of a steel plate material and includes a first sheet 51 and a second sheet 52 of different shapes, and by overlapping these first sheet 51 and second sheet 52, the plate thickness dimension of the convex portion 34 is made smaller than the plate thickness dimension of the flat portion 35.

[0078] Fig.15 (a) is a top view of the first sheet 51, Fig.15 (b) is a top view of the second sheet 52. Fig.15As shown in (a), the first sheet 51 has a yoke forming portion 31 and a plurality of tooth forming portions 32, and groove recesses 33 are formed between each tooth forming portion 32. The tooth forming portion 32 is provided with convex portions 34 arranged at a predetermined interval in the circumferential direction, and a flat portion 35A is formed between each convex portion 34. The convex portion 34 is provided radially outside the groove recess 33. In the first sheet 51, in the yoke forming portion 31, the convex portions 34 and the flat portions 35A are alternately and continuously provided in the circumferential direction.

[0079] On the other hand, Fig.15 As shown in (b), the second piece 52 has a yoke forming portion 31 and a plurality of tooth forming portions 32, and groove recesses 33 are formed between each tooth forming portion 32. In addition, the second piece 52 is different from the first piece 51 in that, in the yoke forming portion 31, the radially outer side of the groove recesses 33 is a cutout portion 53 (blank portion) without a convex portion 34, and the flat portion 35B is formed between the cutout portions 53 in the circumferential direction. That is, the second piece 52 is composed of the portion of the first piece 51 other than the convex portion 34.

[0080] In this embodiment, the structure in which the first sheet 51 and the second sheet 52 overlap each other is used as the core sheet 30, and the core sheet 30 makes the yoke forming part 31 and the tooth forming part 32 of the first sheet 51 and the second sheet 52 close to each other. In this case, the first sheet 51 and the second sheet 52 overlap each other in a state in which the yoke forming part 31 and the tooth forming part 32 are respectively aligned. Thus, in the core sheet 30, the convex part 34 of the first sheet 51 and the notch part 53 of the second sheet 52 are arranged at the same position.

[0081] Here, in the first piece 51, between the radial innermost side and the radial outermost side (outer peripheral edge portion) of the yoke forming portion 31, the flat portion 35A is continuously provided in the circumferential direction in the Y portion on the outer peripheral edge side, and the convex portion 34 is provided radially inward of the Y portion. In other words, in the first piece 51, the convex portion 34 is formed in the range from the radial innermost side to the radial middle position in the yoke forming portion 31. In addition, in the second piece 52, similarly, between the radial innermost side and the radial outermost side (outer peripheral edge portion) of the yoke forming portion 31, the flat portion 35B is continuously provided in the circumferential direction in the Y portion on the outer peripheral edge side, and the cutout portion 53 is provided radially inward of the Y portion. As a result, in the second piece 52, in a state where the second piece 52 overlaps with the first piece 51, the portions on both sides of the convex portion 34 in the circumferential direction are continuous on the outer peripheral edge side.

[0082] like Fig.16 As shown in (a), when the plate thickness dimension of the flat portion 35A is set to T31 and the plate thickness dimension of the convex portion 34 is set to T32 in the first piece 51, the relationship between these T31 and T32 is T31 = T32. That is, in the first piece 51, the convex portion 34 is formed by bending without thinning the steel plate material.

[0083] In addition, if Fig.16 As shown in (b), in a state where the first sheet 51 and the second sheet 52 overlap each other, the flat portions 35A and 35B of each of the first sheet 51 and the second sheet 52 overlap (i.e., closely adhere to each other) to form the flat portion 35, in which the plate thickness dimension T41 of the flat portion 35 is larger than the plate thickness dimension T32 of the convex portion 34. That is, the plate thickness dimensions T32 and T41 are in a relationship of T32<T41. In addition, the plate thickness dimension T41 of the flat portion 35 is preferably the same as the thickness T33 in the stacking direction of the convex portion 34. However, T41>T33 may also be satisfied.

[0084] Fig.16 (c) shows a state where the core sheet 30 including the first sheet 51 and the second sheet 52 is stacked in multiple layers. In this state, the convex portions 34 and the flat portions 35 of the core sheet 30 overlap each other in the stacking direction, and no gap is formed between the flat portions 35. Fig.16 As shown in (b), the stator core 11 has a structure in which the first sheet 51 is provided in the first layer as the axial end face, and the core sheets 30 including the first sheet 51 and the second sheet 52 are stacked in the second layer and thereafter. However, a structure in which the core sheets 30 including the first sheet 51 and the second sheet 52 are stacked in the entire layer of the stator core 11 (a structure in which the second sheet 52 is arranged in the axial end face) may also be adopted.

[0085] When manufacturing the stator core 11, a first sheet 51 and a second sheet 52 are prepared, which are respectively formed into a predetermined flat plate shape by, for example, stamping of a steel sheet material. Then, while bending each of the first sheet 51 and the second sheet 52 into an arc shape and feeding them at the same speed, they are overlapped to form the core sheet 30, and the cylindrical stator core 11 is manufactured by stacking multiple layers of the core sheet 30. In this case, the first sheet 51 is bent into a substantially arc shape at the yoke forming portion 31 using a bending device. In addition, in the present embodiment, the steel sheet material is not thinned by press rolling, and the convex portion 34 is bent and formed. On the other hand, the second sheet 52 is not bent and formed, but is bent with the same curvature as the first sheet 51. Then, the first sheet 51 and the second sheet 52, which are respectively bent and formed, are overlapped with each other and stacked into multiple layers in this state. Thus, the cylindrical stator core 11 is manufactured.

[0086] Here, the second piece 52 is a portion located radially outward in the yoke forming portion 31 ( Fig.15 Therefore, it is preferred to carry out the operation in which the second sheet 52 is continuously fed out together with the first sheet 51 so that the first sheet 51 and the second sheet 52 overlap each other.

[0087] In addition, the first piece 51 and the second piece 52 are both connected to the flat portions 35A and 35B in the circumferential direction on the radially outer side of the yoke forming portion 31. Therefore, even if the first piece 51 is bent and the second piece 52 is not bent, the circumferential spacing deviation of the tooth forming portion 32 and the groove recessed portion 33 in each of the first piece 51 and the second piece 52 can be suppressed.

[0088] According to this embodiment, the following effects are obtained.

[0089] The core sheet 30 is formed by overlapping a first sheet 51 having a convex portion 34 and being continuous in the circumferential direction, and a second sheet 52 formed by a portion of the first sheet 51 other than the convex portion 34. In this case, by overlapping the first sheet 51 and the second sheet 52, the plate thickness dimension of the flat portion 35 can be relatively increased without reducing the plate thickness of the convex portion 34. Therefore, a structure in which the plate thickness dimension of the convex portion 34 is smaller than the plate thickness dimension of the flat portion 35 can be easily realized.

[0090] In the first sheet 51, the plate thickness of the convex portion 34 is the same as the plate thickness of the portion other than the convex portion (the flat portion 35A), and in the core sheet 30, the plate thickness of the convex portion 34 is smaller than the plate thickness of the flat portion 35 when the second sheet 52 overlaps the first sheet 51. In this case, even if the plate thickness of the convex portion 34 and the flat portion 35A are the same in the first sheet 51, in other words, even if the steel sheet material is not thinned, it is easy to achieve a structure in which the plate thickness of the convex portion 34 is smaller than the plate thickness of the flat portion 35 in the core sheet 30.

[0091] In the first piece 51, the range of the convex portion 34 in the radial direction is set to be from the radial innermost side of the yoke forming portion 31 to the radial middle position, thereby making the second piece 52 have a structure in which the parts on both sides of the circumferential direction of the convex portion 34 in the yoke forming portion 31 are continuous at the radial outermost side. As a result, the first piece 51 and the second piece 52 are both continuous in the longitudinal direction, and the operation of overlapping these first pieces 51 and second pieces 52 can be appropriately performed.

[0092] (Other embodiments)

[0093] For example, the above-described embodiment can be modified as follows.

[0094] In the second embodiment described above, the plate thickness dimension T31 of the flat portion 35A and the plate thickness dimension T32 of the convex portion 34 are made equal in the first sheet 51 (see Fig.16(a)), but this can also be changed. For example, in the first piece 51, the plate thickness dimension T32 of the protrusion 34 can also be made smaller than the plate thickness dimension T31 of the flat portion 35A. In this case, the first piece 51 can form the protrusion 34 by bending and thinning the steel plate material. In addition, in the first piece 51, it can also be a structure in which the protrusion 34 is thinned by stretching accompanied by the bending of the steel plate material. In short, the iron core piece 30 only needs to make the plate thickness dimension T32 of the protrusion 34 smaller than the plate thickness dimension T41 of the flat portion 35 when the first piece 51 and the second piece 52 overlap.

[0095] In the second embodiment described above, the first piece 51 and the second piece 52 are both structures that connect the flat portions 35A and 35B in the circumferential direction on the radially outer side of the yoke forming portion 31 (see Fig.15 (a) and (b)), but the structure may be changed. For example, in the first sheet 51, the convex portion 34 is provided in the range from the radial innermost side to the radial outermost side of the yoke forming portion 31 (i.e., the entire radial area of ​​the yoke forming portion 31). In this case, the second sheet 52 is divided by the convex portion 34 of the first sheet 51, and the second sheet 52 overlaps with the first sheet 51 on both sides of the convex portion 34 in the circumferential direction.

[0096] In the above-mentioned embodiments, the convex portion 34 is provided for each groove concave portion 33 in the core sheet 30, but this may be changed. For example, a convex portion 34 may be provided for each of n (n is 2 or more) groove concave portions 33 arranged in the circumferential direction in the core sheet 30. Alternatively, a plurality of convex portions 34 may be provided for each groove concave portion 33 in the core sheet 30.

[0097] In the above-mentioned embodiments, the convex portion 34 is provided radially outside the groove recess 33 in the yoke forming portion 31 of the core piece 30, but this may be changed. Fig.17 As shown, in the core sheet 30, the convex portion 34 extending in the radial direction is provided in a manner continuous between the yoke forming portion 31 and the tooth forming portion 32. In this structure, in the core sheet 30, the yoke convex portion 61 is provided as the convex portion 34 in the yoke forming portion 31, and the tooth convex portion 62 is provided in the tooth forming portion 32. The yoke convex portion 61 and the tooth convex portion 62 are provided in a manner continuous in the radial direction. In addition, between the circumferentially adjacent yoke convex portions 61, that is, the radial outer side of the groove recess 33 becomes a flat portion 35. In this structure, as in the above, the plate thickness dimensions of the convex portions 61, 62 and the flat portion 35 may be different, and the plate thickness dimensions of the convex portions 61, 62 may be smaller than the plate thickness dimension of the flat portion 35.

[0098] In the above-mentioned embodiments, the stator core 11 is a spiral core structure in which the core pieces 30 are spirally stacked, but this can also be changed. For example, a plurality of core pieces 30 in a circular ring shape can be prepared, and the stator core 11 can be manufactured by stacking the core pieces 30. In this case, each core piece 30 in the stacking direction can be bent into a circular ring shape by the convex portion 34.

[0099] The stator core may be used for an inner rotor type rotating electric machine or an outer rotor type rotating electric machine. In the case of a stator core used for an outer rotor type rotating electric machine, a plurality of teeth are provided so as to protrude radially outward from a cylindrical back yoke.

Claims

1. A stator core of a rotating electric machine, the stator core comprising an annular back yoke and a plurality of teeth radially protruding from the back yoke, the stator core being formed by laminating core sheets in multiple layers, characterized in that: The core sheet has convex portions, which are arranged at predetermined intervals in the circumferential direction, are in a bent shape convex in the stacking direction, and extend in the radial direction, and the convex portions are stacked in a state of overlapping each other in the stacking direction. The convex portion and a flat portion between the convex portions adjacent to each other in the circumferential direction have different plate thicknesses, and the plate thickness of the convex portion is smaller than the plate thickness of the flat portion.

2. The stator core of a rotating electrical machine according to claim 1, characterized in that: The core sheet has a structure in which the thickness of the steel plate material constituting the core sheet is different between the convex portion and the flat portion. The convex portion has a structure in which the protrusion height is large on the radial inner side and small on the radial outer side of the back yoke, and is formed so as to protrude from the flat portion also at the radial outermost portion of the back yoke.

3. The stator core of a rotating electrical machine according to claim 2, characterized in that: In the convex part, the concave side is the inner concave part, At the radially outermost portion of the convex portion, the depth dimension of the inner concave portion is equal to or greater than the plate thickness dimension of the flat portion.

4. The stator core of a rotating electrical machine according to claim 2, characterized in that: In the core sheet, the protrusion is in a triangular mountain shape, and the angle of the triangular top of the protrusion is different between the radial inner side and the radial outer side of the back yoke. In the convex portion, the angle of the triangular apex is larger and the plate thickness is larger on the radially outer side of the back yoke than on the radially inner side of the back yoke.

5. The stator core of a rotating electrical machine according to claim 1, characterized in that: The core sheet includes a first sheet and a second sheet, the first sheet having the convex portion and being continuous in the circumferential direction, the second sheet being composed of a portion of the first sheet excluding the convex portion, and the core sheet is composed of the first sheet and the second sheet overlapping each other in a stacking direction, In the core sheet, in a state where the second sheet is overlapped with the first sheet, a plate thickness dimension of the convex portion is smaller than a plate thickness dimension of the flat portion.

6. The stator core of a rotating electrical machine according to claim 5, characterized in that: The plate thickness of the convex portion of the first sheet is the same as the plate thickness of the portion other than the convex portion. In the core sheet, in a state where the second sheet is overlapped with the first sheet, a plate thickness dimension of the convex portion is smaller than a plate thickness dimension of the flat portion.

7. The stator core of a rotating electrical machine according to claim 5, characterized in that: The convex portion is formed in the first sheet in a range from the radial innermost side to the radial middle position in the back yoke, In the second sheet, in a state where the second sheet and the first sheet are overlapped, portions on both sides in the circumferential direction of the convex portion are continuous at the outermost sides in the radial direction.

8. The stator core of a rotating electrical machine according to any one of claims 1 to 7, characterized in that: The teeth protrude in a direction extending radially inward from the back yoke, The top of the convex portion is formed to be flat within a predetermined radial range including the radial innermost side.

9. The stator core of a rotating electrical machine according to any one of claims 1 to 7, characterized in that: The core piece of one or more layers serving as axial end portions is cut away from at least a portion including a top portion of the protrusion.

10. The stator core of a rotating electrical machine according to any one of claims 1 to 7, characterized in that: The core sheet has a yoke forming portion as a portion forming the back yoke, and has a tooth forming portion as a portion forming the teeth, The yoke forming portion has a rolled portion at a radial edge on the opposite side to the tooth forming portion, and the rolled portion forms a portion between the convex portions in the circumferential direction in an arc shape in a plan view.

11. The stator core of a rotating electrical machine according to any one of claims 1 to 7, characterized in that: The core sheet has a yoke forming portion as a portion forming the back yoke, and has a tooth forming portion as a portion forming the teeth, The yoke forming portion has a rolled portion at a radial edge on the opposite side from the tooth forming portion and at a location other than the protrusions, and the rolled portion forms a portion between the protrusions in the circumferential direction in an arc shape in a plan view.

Images