Manufacturing method of motor core component and manufacturing method of stator

Abstract

To provide a manufacturing method of motor cores capable of enhancing a coil space factor of a motor core prepared by annularly arranging substantially U-shaped core components, and to provide a manufacturing method of stators therefor.SOLUTION: A manufacturing method of motor core components according to the present invention comprises: an electromagnetic steel plate preparation step of preparing a plurality of electromagnetic steel plates 35 (35a) each having a length adjusted in such a manner that a tip becomes flat after bending; a lamination step of laminating the electromagnetic steel plates in order of length in such a manner that a center portion becomes linear; a welding step of performing welding 34 the center portion of the laminated electromagnetic steel plates in a thickness direction to obtain a core block 36 in which the electromagnetic steel plates are integrated with each other; a bending step of bending the core block toward a shortest electromagnetic steel plate in a substantially U-shape; and a heat treatment step of annealing the core block while keeping the core block bent.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a core component used in an outer stator type motor, and a method for manufacturing a stator using the core component. [Background technology]

[0002] Motors are used in a variety of devices, including electric cars, electric motorcycles, electric bicycles, drones, ships, electric lawnmowers, and generators.

[0003] For example, in the case of a three-phase DC outer stator brushless motor, the motor is configured with a stator on the outer periphery and a rotor on the inner periphery. The stator is configured with a stator core with multiple teeth erected on the inner periphery of an annular yoke made of electromagnetic steel sheet, and coils wound around the teeth. The rotor is configured with multiple magnets arranged circumferentially on the outer periphery to form magnetic poles, and a rotating shaft located at the center and rotatably mounted within the stator.

[0004] When a stator core is manufactured using a press die-cutting method using electromagnetic steel sheets, the material yield is very low at only about 20% if the stator core is annular. For this reason, the stator core may be divided into multiple circumferentially separated cores, which are then assembled into an annular shape, but the material yield is still low at about 50%. Therefore, in Patent Document 1, a stator core is manufactured by combining approximately U-shaped core parts 100 as shown in Figure 18(a).

[0005] The roughly U-shaped core component 100 is fabricated by bending a core block made by stacking and welding electromagnetic steel sheets in the thickness direction. As shown in Fig. 18(a), the fabricated core component has legs 101a and 101b formed by bending both ends of the core block so that their tips approach each other, and a peripheral surface 102 connecting the legs 101a and 101b. The legs 101a and 101b are bent so that their tips point inward, and the peripheral surface 102 has an arc shape that follows the outer shape of the stator core.

[0006] As shown in FIG. 18(b), the core parts 100 are arranged in an annular shape so that the peripheral surface portion 102 forms the outer periphery and the leg portions 101b, 101a of adjacent core parts are in contact with each other to form a stator core.

[0007] As shown in Figure 18(c), the stator core is fabricated by fitting a cylindrical coil 104, which is made by winding a coated wire around a bobbin 103 in advance, onto the legs 101b, 101a of adjacent core parts 100, 100, and then attaching it to a housing (not shown). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-3813 Summary of the Invention [Problem to be solved by the invention]

[0009] 18, the opening width W between the tips of the leg portions 101a, 101b is narrower than that on the peripheral surface portion 102 side. Therefore, in order to insert two bobbins 103 through the opening, the height of the flange portion 103a of the bobbin 103 is restricted to a maximum of W / 2. As a result, the number of turns of the coated wire wound around the bobbin 103 is reduced, and therefore the non-winding space 105 without the coil 104 is large inside the core part 100, and the coil space factor is significantly reduced.

[0010] A decrease in the coil space factor is undesirable because it increases winding resistance, increases copper loss, and increases coil temperature, reducing motor efficiency.

[0011] An object of the present invention is to provide a manufacturing method for a motor core and a manufacturing method for a stator that can increase the coil space factor of a motor core manufactured by arranging approximately U-shaped core parts in an annular shape. [Means for solving the problem]

[0012] The method for manufacturing a core component according to the present invention includes the steps of: an electromagnetic steel sheet preparation step of preparing a plurality of electromagnetic steel sheets whose lengths are adjusted so that their tips become flat after bending; a lamination step of laminating the electromagnetic steel sheets in order of length so that the central portions thereof are linear; a welding step of welding the central portions of the stacked electromagnetic steel sheets in a thickness direction to obtain a core block in which the electromagnetic steel sheets are integrated; a bending step of bending the core block into a substantially U-shape toward the shortest electromagnetic steel plate; a heat treatment step of annealing the core block in a bent state; Includes:

[0013] The bending step is a step of bending the core block into an approximately U-shape having two legs on both sides and an arc-shaped peripheral surface connecting the legs, and the legs can be bent so that the spacing at the tip end becomes narrower.

[0014] The bending step is a step of bending the core block into an approximately U-shape having two legs on both sides and an arc-shaped peripheral surface connecting the legs, and the legs can be bent so that they are parallel.

[0015] The heat treatment step can be carried out by mounting the core block bent into a substantially U-shape on a heat treatment jig that holds the core block in a bent state.

[0016] Further, the method for manufacturing a core component according to the present invention includes the steps of: a winding step of winding the strip-shaped electromagnetic steel sheet around a winding jig having a circular arc-shaped bottom to obtain a core wound body; a welding step of welding the bottom side of the core wound body in the thickness direction; a heat treatment step of annealing the core winding; and a cutting step in which two sides of the heat-treated core wound body sandwiching the bottom side are cut so that the tips are flat, thereby forming a substantially U-shaped body having two leg portions on both sides and an arc-shaped peripheral portion connecting the leg portions; Includes:

[0017] The winding jig may be an isosceles triangle with rounded corners and an arc-shaped base.

[0018] The winding jig may be a rounded rectangle with an arc-shaped base.

[0019] The method for manufacturing a stator of the present invention includes: a core part preparation step of preparing a specified number of core parts manufactured by the core part manufacturing method, the core parts having narrow spacing at the tip ends of the leg parts, which form a ring when arranged with the peripheral surface parts on the outer periphery side; a cylindrical coil fabrication step of fabricating the specified number of cylindrical coils by winding a coated wire in multiple layers so that the number of windings gradually increases in an axial direction perpendicular to the winding direction, the cylindrical coil having an inner diameter that fits into the adjacent leg portions when the two core parts are arranged side by side; an arranging step of applying a biasing force in an opening direction of the core part so that the legs are parallel, and then applying a biasing force to the adjacent core part in the same manner to open the core part so that the legs are parallel, and arranging the opened core parts so that the legs are adjacent to each other; a starting end cylindrical coil mounting step of fitting the cylindrical coil into a core part located at the starting end; a cylindrical coil mounting step of fitting the cylindrical coil onto the adjacent leg portions of the parallel core parts from the multilayer side having a larger number of windings; and an insertion step of repeating the juxtaposition step and the cylindrical coil attachment step, arranging the core parts one less than the specified number in parallel, attaching the cylindrical coil, and then releasing the urging force applied to the core parts, connecting the core parts one less than the specified number with the cylindrical coil to form a ring shape, fitting the cylindrical coil into the core part located at the end, inserting the last core part into the cylindrical coils at the start and end while applying the urging force so that the legs are parallel, and after insertion, releasing the urging force, causing the core parts to return to their original state by a restoring force so that the spacing at the tip ends of the legs becomes narrower; Includes:

[0020] Further, the method for manufacturing a stator of the present invention includes the steps of: a core component preparation step of preparing a specified number of core components manufactured by the core component manufacturing method, each having parallel legs, that form a ring when arranged with the peripheral surface portion on the outer periphery side; a cylindrical coil fabrication step of fabricating the specified number of cylindrical coils by winding a coated wire in multiple layers so that the number of windings gradually increases in an axial direction perpendicular to the winding direction, the cylindrical coil having an inner diameter that fits into the adjacent leg portions when the two core parts are arranged side by side; an arranging step of arranging the core parts next to each other so that the legs are adjacent to each other; a starting end cylindrical coil mounting step of fitting the cylindrical coil into a core part located at the starting end; a cylindrical coil mounting step of fitting the cylindrical coil onto the adjacent leg portions of the parallel-arranged core parts from the side having the larger number of windings; an insertion step of repeating the juxtaposition step and the cylindrical coil attachment step, juxtaposing the core parts one less than the specified number, attaching the cylindrical coil, applying an external force to narrow the spacing at the tip ends of the legs of the core parts, connecting the core parts one less than the specified number with the cylindrical coil to form a ring shape, fitting the cylindrical coil into the core part located at the end, and inserting the last core part into the cylindrical coil at the start and end while applying a biasing force so that the legs are parallel; a molding step of applying an external force to narrow the gaps between the tip ends of all the core parts, thereby forming the core parts and the cylindrical coil into an annular shape; Includes:

[0021] In the insertion step, the last core part can be inserted into the core parts connected by the cylindrical coils to form a ring, with the adjacent portions of the starting and ending cylindrical coils positioned at the vertex on the short axis side of the ellipse.

[0022] The cylindrical coil is wound around a bobbin having a winding tube portion with an inner diameter that fits into the adjacent leg portion when the two core parts are lined up side by side, and flange portions that protrude outward from both ends of the winding tube portion, and one of the flange portions, with the number of windings gradually increasing, can be configured to be longer than the other.

[0023] The step of attaching the starting cylindrical coil can be performed before, after, or simultaneously with the step of fitting the terminal cylindrical coil in the inserting step. [Effects of the Invention]

[0024] According to the core component manufacturing method of the present invention, a core component having a substantially U-shape can be obtained.

[0025] Furthermore, according to the stator manufacturing method of the present invention, the core parts are arranged with their legs spread apart in parallel, and the cylindrical coil is inserted, so that a cylindrical coil with a gradually increasing number of windings can be used, thereby increasing the coil space factor. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 is a perspective view of a stator according to one embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the two core parts of FIG. 1 and a part of a bobbin attached thereto. [Figure 3] FIG. 3 is a perspective view of the stator core. [Figure 4] FIG. 4 is a perspective view of the stator core part of the first embodiment. [Figure 5] FIG. 5A is a plan view of the core part of the first embodiment, and FIG. 5B is a plan view of the core part in the state where a biasing force is applied in the direction of arrow A in FIG. 5A to widen the gap between the tips. [Figure 6] FIG. 6 is an explanatory diagram showing a method for manufacturing the core component (bending method) of the first embodiment. [Figure 7] FIG. 7 is a perspective view showing a manufacturing method (bending method) of the core component of the first embodiment. [Figure 8] FIG. 8 is a perspective view of a core part inserted into the heat treatment jig of the first embodiment. [Figure 9] FIG. 9 is an explanatory diagram showing a different manufacturing method (winding method) for the core component of the first embodiment. [Figure 10] FIG. 10 is an explanatory diagram showing a method for manufacturing the stator of the first embodiment. [Figure 11] FIG. 11 is a cross-sectional view of the rectangular area B in FIG. 10(e). [Figure 12] FIG. 12 is an explanatory view showing a process of inserting the last core part of the stator according to the first embodiment. [Figure 13] FIG. 13A is a plan view of a core part of the second embodiment, and FIG. 13B is a plan view of the core part in which an external force is applied in the direction of arrow G in FIG. 13A to narrow the gap between the tips. [Figure 14] FIG. 14 is an explanatory diagram showing a method for manufacturing a core component (bending method) according to the second embodiment. [Figure 15] FIG. 15 is a perspective view of a core part inserted into the heat treatment jig of the second embodiment. [Figure 16] FIG. 16 is an explanatory diagram showing a method for manufacturing a core component (winding method) according to the second embodiment. [Figure 17] FIG. 17 is an explanatory view showing a process of inserting the last core part of the stator according to the second embodiment. [Figure 18] FIG. 18 shows (a) a plan view of a conventional core part, (b) a view of two core parts arranged side by side, and (c) a cross-sectional view with a bobbin inserted. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, a core component 30 according to one embodiment of the present invention and a method for manufacturing a stator 10 using the core component 30 will be described with reference to the drawings.

[0028] First, we will explain the stator 10 of the present invention. The stator 10 of the present invention is an outer stator configured by arranging a plurality of stator core parts 30 (appropriately referred to as "core parts") in an annular shape as shown in Fig. 1, and attaching a cylindrical coil 60 to the legs 32a, 32b of adjacent core parts 30, 30 as shown in Figs. 1 and 2.

[0029] 3 is a perspective view of the stator core 12 in FIG. 1 with the cylindrical coil 60 removed and only the core parts 30 arranged in an annular shape. The stator core 12 is composed of a plurality of core parts 30, twelve in FIG. 3, arranged in an annular shape. As shown in FIG. 4, each core part 30 is formed by stacking a plurality of electromagnetic steel sheets 35. Either grain-oriented or non-oriented electromagnetic steel sheets may be used as the electromagnetic steel sheets 35; however, grain-oriented electromagnetic steel sheets are preferable because they have lower iron loss, higher magnetic permeability, and higher saturation magnetic flux density than non-oriented electromagnetic steel sheets.

[0030] The core part 30 is formed by bending an electromagnetic steel sheet 35 into a substantially U-shape, and includes two legs 32a, 32b and an arc-shaped peripheral surface 31 connecting the legs 32a, 32b. More specifically, the legs 32a, 32b are bent from the peripheral surface 31 so that the distance W between their tips 33 narrows. The corners connecting the peripheral surface 31 and the legs 32a, 32b are rounded. In the present invention, the shape of the core part 30 in which the distance W between the tips of the legs 32a, 32b is narrow, as shown in FIG. 4, is referred to as a "narrowed U-shape."

[0031] The core part 30 is ultimately assembled into the stator 10 in a narrowed U-shape, but the core part 30 itself can be manufactured in advance in a narrowed U-shape as shown in the first embodiment below, or in a shape in which the legs 32a, 32b are approximately parallel (hereinafter referred to as a "parallel U-shape") as shown in the second embodiment.

[0032] First Embodiment In the first embodiment, the core part 30 is manufactured in a narrow U-shape.

[0033] The first embodiment is characterized in that, as shown in Fig. 5(a), a narrowed U-shaped core part 30 is produced, and in the process of assembling the stator 10, a biasing force is applied in the direction of arrow A to open the legs 32a, 32b until they become substantially parallel, as shown in Fig. 5(b), and the distance between the tips 33, 33 is set to W1, which is wider than W, to hold the core part 30 in a parallel U-shape. Then, the biasing force is released, so that the distance between the tips 33, 33 can be returned to W, as shown in Fig. 5(a).

[0034] Core components made of laminated electromagnetic steel sheets are generally manufactured by winding the sheets into a predetermined shape, annealing them, and then impregnating them with varnish to fix the shape. Once the shape of this type of core component is fixed, it cannot be deformed to open the legs. Forcibly deforming the core component would significantly reduce magnetic properties such as core loss, magnetic permeability, and saturation magnetic flux density. For this reason, it was not possible to deform a narrow-U-shaped core component 30 into a parallel U-shape, as shown in FIG. 5 .

[0035] The inventors have confirmed that, by subjecting a core component 30 made of electromagnetic steel sheet 35 to an annealing heat treatment but not to a varnish impregnation treatment, the core component 30 can be transformed from a narrowed U-shape shown in FIG. 5(a) to a parallel U-shape shown in FIG. 5(b) by applying a biasing force to the legs 32a and 32b in the direction of arrow A. After the biasing force is released, the core component 30 returns to the narrowed U-shape shown in FIG. 5(a) due to a restoring force. They have also found that the magnetic properties of the core component 30, such as iron loss, magnetic permeability, and saturation magnetic flux density, do not deteriorate. Furthermore, they have found that the annealing heat treatment enhances springback, preventing the tips of the legs 32a and 32b from separating during the transformation from the narrowed U-shape to the parallel U-shape.

[0036] The core component 30 can be produced by a method in which a plurality of electromagnetic steel sheets 35a of a predetermined length are prepared, stacked, and bent (hereinafter referred to as the "bending method"), as shown in Figures 6 and 7, or by a method in which the core component 30 is wound around a winding jig 50 and then cut (hereinafter referred to as the "winding method"), as shown in Figure 9. Of course, the core component 30 can also be produced by methods other than these exemplary manufacturing methods. The bending method has a material yield of 100%, making it extremely effective for resource conservation and decarbonization when melting and recycling waste materials.

[0037] <Bending manufacturing method> The bending method is a method for producing a core component 30 from electromagnetic steel sheets 35a of different lengths, as shown in FIGS.

[0038] First, a plurality of electromagnetic steel sheets 35a are prepared, the lengths of which are adjusted so that the tips 33, 33 of the legs 32a, 32b are flat after bending, as shown in FIGS. 6(c) and 7(c) (electromagnetic steel sheet preparation step). The tips 33, 33 of the legs 32a, 32b being flat can be formed as flat surfaces, as shown in FIGS. 2, 4, 6(c), and 7(c), or as arcs along the inner circumferential surface of the stator 10 in which the rotor is mounted. When the clearance between the rotor and the stator 10 is small or when the number of stator poles is small, it is preferable that the tips 33, 33 of the legs 32a, 32b be arcs.

[0039] In one embodiment, the electromagnetic steel sheets 35a may have a thickness of 50 μm to 500 μm, and any number of sheets may be stacked. The width and length of the electromagnetic steel sheets 35a are appropriately set depending on the inner diameter, outer diameter, and number of teeth of the stator 10 to be manufactured.

[0040] The electromagnetic steel sheets 35a prepared in the electromagnetic steel sheet preparation step are stacked lengthwise so that the central portions are linear, as shown in Figures 6(a) and 7(a) (stacking step). In the illustrations, the electromagnetic steel sheets 35a are stacked so that the longer electromagnetic steel sheets 35a are the bottom layers. Alternatively, a mold resembling two descending steps facing each other may be used to stack the shorter electromagnetic steel sheets 35a so that the bottom layers are the bottom layers.

[0041] The electromagnetic steel sheets 35a stacked in the stacking step are welded 34 in the thickness direction at their central portions, as shown in Figures 6(b) and 7(b), to obtain a core block 36 in which the electromagnetic steel sheets 35a are integrated together (welding step).

[0042] Next, as shown in Figures 6(c) and 7(c), the core block 36 is bent toward the shortest electromagnetic steel sheet 35a in a U-shape at its tip (bending step). The bending of the core block 36 can be performed by inserting the core block 36 into a mold that matches the final shape of the core part 30. The mold may include pressing members that press the core block 36 from the left and right to narrow the distance W between the tips of the leg parts 32a, 32b, thereby forming the core part 30 in a narrow U-shape.

[0043] 6(c) and 7(c) show the core block 36 obtained by the bending step. The core block 36 has an arc-shaped peripheral surface 31 with rounded corners at both ends. Legs 32a, 32b extend from both ends of the peripheral surface 31 of the core block 36 toward the center of the arc of the peripheral surface 31. The legs 32a, 32b have flat tips 33, and the core block 36 is molded into a narrow U-shape with a narrow spacing W between the tips 33 of the legs 32a, 32b, the same as the final shape of the core part 30.

[0044] The core block 36 obtained in the bending step has poor magnetic properties and other performance characteristics due to the influence of external stress, and the electromagnetic steel sheet 35a itself has residual stress, giving it a spring property that causes it to return to its original shape when bent. Therefore, when the core block 36 is removed from the mold, the tips 33, 33 of the legs 32a, 32b open, which is a problem. For this reason, the core block 36 is subjected to a heat treatment while maintaining its bent shape (heat treatment step).

[0045] The heat treatment step is a process of annealing the core block 36 while maintaining the bent state of the core block 36. In order to maintain the bent state of the core block 36, the core block 36 can be fitted into a heat treatment jig 40 as shown in FIG. 8 and subjected to heat treatment. The heat treatment jig 40 has an inner surface that is the same as the final shape of the core part 30, and the bent core block 36 can be inserted into the heat treatment jig 40 and placed in a heat treatment furnace as is. The heat treatment jig 40 may also be configured as a multiple-piece structure that is assembled with bolts or the like.

[0046] In the heat treatment step, the core block 36 is desirably annealed by maintaining it at, for example, 750°C to 850°C for at least one hour. Annealing improves various performance characteristics of the core block 36, such as its magnetic properties. Furthermore, the core block 36 becomes the core component 30 whose shape is fixed in its final shape. In other words, even when the core component 30 is removed from the heat treatment jig 40 after the heat treatment step, the final shape is maintained. Note that the core component 30 is not subsequently subjected to a varnish impregnation treatment.

[0047] After the above heat treatment step is completed, the bending method is completed by removing the core part 30 from the heat treatment jig 40. Figure 4 is a perspective view of the fabricated core part 30.

[0048] <Winding method> The winding method is a method of manufacturing a core component 30 by winding a strip-shaped electromagnetic steel sheet 35b, and then cutting the core component 37, as shown in FIG.

[0049] In one embodiment, the strip-shaped electromagnetic steel sheet 35b may have a thickness of 50 μm to 500 μm and may be wound any number of times. The width and length of the strip-shaped electromagnetic steel sheet 35b are set appropriately depending on the inner diameter, outer diameter, and number of teeth of the stator 10 to be manufactured.

[0050] In the winding method, a strip-shaped electromagnetic steel sheet 35b is wound around a winding jig 50 as shown in FIG. 9(a) to obtain a core wound body 37 (winding step). The winding jig 50 may be in the form of an isosceles triangle with a rounded corner and a base 51 that is an arc. The winding jig 50 has a support part 52 that is attached to the rotating shaft of a motor (not shown). One end of the strip-shaped electromagnetic steel sheet 35b is attached to the winding jig 50, and the winding jig 50 is rotated around the support part 52, whereby the strip-shaped electromagnetic steel sheet 35b is wound around the outer periphery of the winding jig 50, thereby obtaining the core wound body 37. The end of the strip-shaped electromagnetic steel sheet 35b may be fixed to the outer periphery of the core wound body 37 by welding or the like.

[0051] If the start and end of the strip-shaped electromagnetic steel sheet 35b are located on the core part 30 in its final shape, the number of turns of the core part 30 will differ between the leg parts 32a and 32b, which may result in variations in magnetic properties. Furthermore, if there are welded portions, they may come into contact with the adjacent core part 30 or the bobbin 62 of the tubular coil 60 when assembling the stator 10, resulting in improper assembly. For this reason, it is desirable to wind the strip-shaped electromagnetic steel sheet 35b so that the start and end of the sheet are located on the side of the scrap material 38a that will be discarded in Figure 9(b) described below.

[0052] The obtained core wound body 37 has, on the bottom side 51 of the winding jig 50, a circular arc-shaped peripheral surface portion 31 that is the same as the final shape of the core part 30, and has a shape in which legs 32a, 32b extend from the rounded corners at both ends of the peripheral surface portion 31 toward the center of the arc of the peripheral surface portion 31. The distance between the legs 32a, 32b becomes narrower the further they are from the peripheral surface portion 31, and the tips of the legs 32a, 32b are connected by a circular arc portion 38.

[0053] Next, the central portion on the base side 51 side of the obtained core wound body 37 having an arc-shaped base side 51 and a rounded isosceles triangle shape is welded 34 in the thickness direction, as shown in Figure 9(a), to integrate the wound electromagnetic steel sheets 35b together (welding step).

[0054] The core wound body 37 produced as described above has low performance in various aspects, such as magnetic properties, and the electromagnetic steel sheet 35b itself has a spring property that allows it to return to its original shape when bent, so that the core wound body 37 opens up into a shape close to a ring when removed from the winding jig 50. For this reason, the core wound body 37 is subjected to a heat treatment (heat treatment step).

[0055] The heat treatment can be performed by placing the core wound body 37 in a heat treatment furnace while it is still wound around the winding jig 50. The heat treatment is preferably performed by annealing the core wound body 37 at 750°C to 850°C for at least one hour. Annealing improves various performance characteristics of the core wound body 37, such as magnetic properties. Furthermore, the shape of the core wound body 37 is fixed in the wound state, as shown in FIG. 9(b). That is, even if the core wound body 37 is removed from the winding jig 50 after the heat treatment step, the shape is maintained without being distorted. The core component 30 is not subsequently subjected to a varnish impregnation process.

[0056] Next, the core wound body 37 is removed from the winding jig 50, and the legs 32a and 32b are cut off at the location indicated by the dotted line C in FIG. 9(b) to obtain the final core component 30 (cutting step). Examples of cutting methods include laser cutting, wire cutting, and cutting with a grindstone. As a result, the portion above the dotted line C is discarded as scrap 38a, resulting in a narrow-ended U-shaped core component 30 having two legs 32a and 32b with a distance W between their tips 33 and an arc-shaped peripheral surface 31 connecting the legs 32a and 32b, as shown in FIG. 9(c). In the winding method, the yield is approximately 70% due to the scrap 38a. However, this method still achieves a higher yield than conventional die-cutting.

[0057] This completes the winding process. Figure 4 is a perspective view of the core part 30 thus fabricated.

[0058] During the process of assembling the stator 10, the core component 30 obtained by the bending and winding methods can be deformed from the narrowed U-shape shown in FIG. 5(a) to a parallel U-shape as shown in FIG. 5(b) by applying a biasing force in the direction of arrow A to the legs 32a, 32b so that the legs 32a, 32b become approximately parallel. Furthermore, by releasing the biasing force in the direction of arrow A from the core component 30, the restoring force of the electromagnetic steel sheet 35 causes the core component 30 to return to the narrowed U-shape shown in FIG. 5(a). It should be noted that the magnetic properties of the core component 30 that has been deformed from the narrowed U-shape to the parallel U-shape and then returned to the narrowed U-shape are almost unchanged from those of the core component before deformation.

[0059] <Stator assembly> The obtained core part 30 is fitted with a cylindrical coil 60 as shown in FIG. 10, and the stator 10 is assembled.

[0060] <Core component preparation steps> First, a predetermined number of core parts 30 are prepared by bending or winding. In the case of the stator 10 of FIG.

[0061] <Cylindrical coil manufacturing steps> Additionally, the same number of cylindrical coils 60 as the specified number are prepared. The cylindrical coil 60 is formed by winding a covered wire 61 into a cylindrical shape as shown in FIGS. 1, 2, and 10. Preferably, the covered wire 61 is wound into a cylindrical shape having an inner diameter that fits into the adjacent legs 32b, 32a when the two core parts 30a, 30b are arranged side by side, specifically, an inner diameter of a substantially rectangular ring. The core part 30 that is deformed from a narrowed U-shape into a parallel U-shape and then restored to its narrowed U-shape in this way has almost no change in magnetic properties from the undeformed narrowed U-shaped core part. Therefore, a cylindrical coil can be used. Therefore, a high-precision, high-speed, and inexpensive winding machine can be used instead of a high-precision nozzle-type winding machine used for annular press-punched stator cores with a fixed shape.

[0062] As shown in Fig. 2, the cylindrical coil 60 is preferably formed by winding a covered wire 61 in layers so that the number of turns in the axial direction perpendicular to the winding direction gradually increases. This is to increase the space factor of the stator 10. The covered wire 61 is preferably an enamel-coated copper wire, but this does not exclude the use of a covered aluminum wire or the like for weight reduction and cost advantage.

[0063] 2, the cylindrical coil 60 is preferably formed by winding a coated wire 61 in multiple layers around a bobbin 62 molded from an electrically insulating resin or the like. The bobbin 62 has a winding tube portion 63 having an inner diameter that fits into adjacent leg portions 32b, 32a when the two core parts 30a, 30b are arranged side by side, and flange portions 64a, 64b that protrude outward from both ends of the winding tube portion 63. When the flange portions are inserted into the legs 32b, 32a, the flange portion 64a that faces the circumferential surface portion 31 protrudes outward more than the other flange portion 64b, allowing for a larger number of windings to be applied.

[0064] <Parallel steps> First, as shown in Fig. 5, a biasing force in the direction of arrow A is applied to the legs 32a, 32b of the two core parts 30a, 30b. As shown in Fig. 5(b), a jig or equipment (not shown) such as a chuck or rod arm is used to open the legs 32a, 32b, holding them in a state where the distance between the tips 33, 33 is W1, which is wider than W, forming the core parts 30a, 30b into a parallel U-shape. In this state, the core parts 30a, 30b are arranged so that the legs 32b, 32a are adjacent to each other, as shown in Fig. 10(a). The biasing force is maintained on the core parts 30a, 30b.

[0065] <Starting cylindrical coil installation step> As shown in Figure 10(b), the cylindrical coil 60a is fitted to the leg 32a (leftmost) that serves as the starting end of the core part 30a (the left end in the figure). Note that the starting cylindrical coil 60 may be wobbly because it is fitted to one leg 32a. For this reason, this step of fitting the starting cylindrical coil may be performed before, after, or simultaneously with the step of fitting the terminal cylindrical coil 60l.

[0066] <Cylindrical coil installation step> Next, as shown in Figures 10(c) and 10(d), a cylindrical coil 60b is fitted to the adjacent legs 32b, 32a of the core parts 30a, 30b. As shown in Figure 11, the core parts 30a, 30b are spaced apart so that the legs 32a, 32b are parallel to each other, and the distance between the tips 33, 33 is W1, which is wider than W. Therefore, even if the number of windings of the cylindrical coil 60 gradually increases, the adjacent legs 32b, 32a can be fitted without colliding with each other and without interfering with jigs or equipment (not shown), such as chucks or rod arms, that apply a biasing force. Furthermore, by guiding the core parts 30 on a single rail, it is possible to manufacture and install the cylindrical coils in a continuous winding without cutting the crossover wires between them, which simplifies the connection, improves reliability, and reduces copper loss.

[0067] <Insertion step> The above-described arranging step and cylindrical coil attachment step are repeated to sequentially add core parts 30c, 30d, ..., 30k, and attach cylindrical coils 60c, 60d, ..., 60k, as shown in Figures 10(d) and 10(e). Then, with the number of core parts 30a to 30k that is one less than the specified number arranged in parallel, the last cylindrical coil 60l is fitted onto leg 32b of core part 30k, which is the final core part.

[0068] Next, the biasing force on the core parts 30a to 30k is released. As a result, the core parts 30a to 30k return to a narrowed U-shape due to the restoring force, as shown in Fig. 12, and the stator core 12 itself assumes a substantially annular shape (see Fig. 12). The cross section of each core part 30 and the inserted cylindrical coil 60 is as shown in Fig. 2.

[0069] In this state, a biasing force in the direction of arrow A is applied to the last core part 30l as shown in FIG. 5, spreading the legs 32a, 32b into a parallel U-shape, and maintaining the distance W1 between the tips 33, 33 wider than W. Then, as shown in FIG. 12, the legs 32b, 32a of the core part 30l are inserted into the starting and ending cylindrical coils 60a, 60l. Thereafter, the biasing force on the last core part 30l is released. This completes the stator 10, as shown in FIG. 1, in which the peripheral surface 31 of the core part 30 forms an annular outer periphery and the legs 32b, 32a of the adjacent core parts 30, 30 function as teeth and the cylindrical coils 60 are fitted into each other.

[0070] In the insertion step, some ingenuity is required to smoothly insert the last core part 30l, which is fitted between the starting and ending core parts, of the core parts 30a to 30k connected together by the cylindrical coil 60 to form a ring. Therefore, in the insertion step of the present invention, the ring-shaped core parts 30a to 30k connected together by the cylindrical coil 60 are flattened so that the adjacent portion D between the starting and ending cylindrical coils 60a and 60l is located at the apex E on the minor axis side of an ellipse with the center O, and the last core part 30l is inserted in the direction of arrow F. This allows the last core part 30l to be smoothly inserted without the legs 32b, 32a interfering with the cylindrical coils 60a, 60l.

[0071] As described above, according to the present invention, the narrowed U-shaped core part 30 is opened into a parallel U shape, and then the cylindrical coils 60 are sequentially attached to obtain the annular stator 10. The shape of the stator 10 can be fixed by varnish impregnation or resin molding, as necessary.

[0072] The obtained stator 10 can be used as a motor by, for example, mounting it in a resin housing and rotatably mounting a rotor with permanent magnets arranged in an annular shape on the inner periphery.

[0073] As shown in FIG. 2, in the stator 10 of the present invention, a bobbin 62 with an increasing number of turns of covered wire 61 can be fitted into the legs 32a, 32b on the peripheral surface portion 31 side, thereby reducing the non-winding space 65 where no covered wire 61 is present within the core component 30. The reduction in the non-winding space 65 can be confirmed by comparing it with the conventional non-winding space 105 shown in FIG. 18(c). In the stator 10 of the present invention, the non-winding space 65 is smaller than the conventional non-winding space 105, so the space factor can be increased by approximately 5% to 15%. The increased space factor reduces winding resistance, reduces copper loss, and suppresses coil temperature increases, improving motor efficiency.

[0074] Second Embodiment In the second embodiment, the core component 30 is manufactured in a parallel U-shape. The same reference numerals as those in the first embodiment denote the same or equivalent components.

[0075] In the second embodiment, as shown in Fig. 13(a), a parallel U-shaped core part 30 is produced with a distance W1 between the tips 33, 33 of the leg parts 32a, 32b. Then, in the process of assembling the stator 10, a biasing force is applied to assemble the core part 30 so that the distance W between the tips 33, 33 of the leg parts 32a, 32b is narrower than W1, as shown by arrow G in Fig. 13(b).

[0076] The inventors have found that by performing an annealing heat treatment on core component 30 formed from electromagnetic steel sheet 35 in a predetermined shape but not performing a varnish impregnation treatment, core component 30 can be changed from the parallel U-shape shown in Fig. 13(a) to the narrow U-shape shown in Fig. 13(b) by applying a biasing force to legs 32a, 32b in the direction of arrow G, with only a slight decrease in magnetic properties such as iron loss and magnetic flux density. As a result, legs 32a, 32b become parallel to each other, and the distance between tips 33, 33 is W1, which makes it easy to install and assemble the cylindrical coil. Furthermore, even when the core part 30 is subjected to annealing heat treatment, as shown in Figure 17, during the assembly process into the approximately annular shape of the core parts 30a to 30k, external stress is applied in the direction of arrow G to each of the core parts 30a to 30k so that the distance between the tips 33, 33 narrows to W from the parallel U-shape as shown in Figure 13(a). As a result, the core parts 30a to 30k are deformed from the parallel U-shape to the narrow U-shape as shown in Figure 13(b). It has been found that, due to the effect of springback caused by the residual stress generated in the process, the tips of the legs 32a, 32b do not come apart during the process of deformation from the parallel U-shape to the narrow U-shape.

[0077] The core component 30 can be produced by a method in which a plurality of electromagnetic steel sheets 35a of a predetermined length are prepared, stacked, and bent (hereinafter referred to as the "bending method"), as shown in Fig. 14, or by a method in which the core component 30 is wound around a winding jig 50 and then cut (hereinafter referred to as the "winding method"), as shown in Fig. 16. Of course, the core component 30 can also be produced by methods other than these exemplary manufacturing methods. The bending method has a 100% yield and is extremely effective in saving resources.

[0078] <Bending manufacturing method> The bending method is a method for producing a core component 30 from electromagnetic steel sheets 35a of different lengths, as shown in FIG.

[0079] The electromagnetic steel sheets 35a are prepared in a narrow U-shape (see FIG. 13(b)) incorporated into the stator 10, with the lengths adjusted so that the tips 33, 33 of the legs 32a, 32b are flat (electromagnetic steel sheet preparation step). The flat tips 33, 33 can be formed in a form in which the tips 33, 33 of the core part 30 are flat, as shown in FIG. 13(b), or in an arc shape that follows the inner peripheral surface of the stator 10 in which the rotor is mounted. When the clearance between the rotor and the stator 10 is small or when the number of stator poles is small, it is preferable that the tips 33, 33 of the legs 32a, 32b be arc-shaped.

[0080] The type and thickness of the electromagnetic steel sheet 35a in the second embodiment are the same as those in the first embodiment.

[0081] The electromagnetic steel sheets 35a prepared in the electromagnetic steel sheet preparation step are stacked lengthwise so that the central portions are linear, as shown in Fig. 14(a) (stacking step). In the drawing, the electromagnetic steel sheets 35a are stacked so that the longer electromagnetic steel sheets 35a are the bottom layers. Alternatively, a mold resembling two descending steps facing each other may be used to stack the shorter electromagnetic steel sheets 35a so that the bottom layers are the bottom layers.

[0082] As shown in FIG. 14(b), the electromagnetic steel sheets 35a stacked in the stacking step are welded 34 at their central portions in the thickness direction to obtain a core block 36 in which the electromagnetic steel sheets 35a are integrated together (welding step).

[0083] Next, as shown in Fig. 14(c), the core block 36 is bent so that its tip is U-shaped toward the shortest electromagnetic steel sheet 35a (bending step). The bending of the core block 36 can be performed by inserting the core block 36 into a mold that is shaped to match the final shape of the core part 30. The mold can be provided with pressing members that press the core part 30 from the left and right so that the legs 32a, 32b are parallel and spaced apart by W1, thereby forming the core part 30 into a parallel U-shape.

[0084] 14(c) shows the core block 36 obtained by the bending step. The core block 36 has an arc-shaped peripheral surface 31 with rounded corners at both ends. Legs 32a and 32b extend substantially parallel to each other from both ends of the peripheral surface 31 of the core block 36.

[0085] The core block 36 obtained in the bending step has poor magnetic properties and other performance characteristics due to the applied external stress, and the electromagnetic steel sheet 35a itself has a spring property that causes it to return to its original shape when bent. Therefore, when the core block 36 is removed from the mold, residual stress causes the tips 33, 33 of the legs 32a, 32b to open, which is a problem. For this reason, the core block 36 is subjected to a heat treatment while maintaining its bent shape (heat treatment step).

[0086] The heat treatment step is a process of annealing the core block 36 while maintaining the bent state. In order to maintain the bent state of the core block 36, the core block 36 can be fitted into a heat treatment jig 40 as shown in FIG. 15 and subjected to heat treatment. The heat treatment jig 40 has an inner surface that is the same as the final shape of the core part 30, and the bent core block 36 can be inserted into the heat treatment jig 40 and placed in a heat treatment furnace as is. The heat treatment jig 40 may also be divided into multiple parts that can be assembled together with bolts or the like.

[0087] In the heat treatment step, the core block 36 is desirably annealed by maintaining it at, for example, 750°C to 850°C for at least one hour. Annealing improves various performance characteristics of the core block 36, such as its magnetic properties. Furthermore, the core block 36 becomes the core component 30 whose shape is fixed in its final shape. In other words, even when the core component 30 is removed from the heat treatment jig 40 after the heat treatment step, the final shape is maintained. Note that the core component 30 is not subsequently subjected to a varnish impregnation treatment.

[0088] After the above heat treatment step is completed, the bending method is completed by removing the core part 30 from the heat treatment jig 40. Fig. 14(c) is a plan view of the produced core part 30.

[0089] <Winding method> The winding method is a method of producing a core wound body 37 by winding a strip-shaped electromagnetic steel sheet 35b, as shown in FIG. 16, and then producing a core component 30 by cutting the core wound body 37.

[0090] The type and thickness of the strip-shaped electromagnetic steel sheet 35b in the second embodiment are the same as those in the first embodiment.

[0091] In the winding method, a strip-shaped electromagnetic steel sheet 35b is wound around a winding jig 50 as shown in FIG. 16(a) to obtain a core wound body 37 (winding step). In this embodiment, the winding jig 50 has an oval-shaped rectangular shape with rounded corners so that two core components 30 can be obtained from one core wound body 37. Specifically, the winding jig 50 has arc-shaped or linear short sides 51, 51 that form the bottom surface of the core component 30, and long sides 51a, 51a that extend linearly and parallel to the rounded corners. The winding jig 50 has a support portion 52 that is attached to the rotating shaft of a motor (not shown). One end of the strip-shaped electromagnetic steel sheet 35b is attached to the winding jig 50, and the winding jig 50 is rotated around the support portion 52, whereby the strip-shaped electromagnetic steel sheet 35b is wound around the outer periphery of the winding jig 50, thereby obtaining the core wound body 37. The end of the strip-shaped electromagnetic steel sheet 35b may be fixed to the outer periphery of the core winding body 37 by welding or the like.

[0092] If the start and end of the strip-shaped electromagnetic steel sheet 35b are located in the core component 30 in its final shape, the number of turns of the core component 30 will differ between the legs 32a and 32b, resulting in variations in magnetic properties. However, the steel sheet on the leg side with the greater number of turns can be removed to achieve the desired alignment. Furthermore, if the start and end are welded for fastening, they may come into contact with adjacent core components 30 or the bobbin 62 of the tubular coil 60 during assembly of the stator 10, resulting in improper assembly. To avoid this, the start and end of the strip-shaped electromagnetic steel sheet 35b can be fixed beyond the cutting line indicated by line H in FIG. 16(b), described below, by a method other than welding, such as by using a mold. This allows the start and end of the strip-shaped electromagnetic steel sheet 35b to be cut along line H without remaining in the core component 30, but can be used as scrap. Furthermore, although the material yield will decrease, when extracting two core parts 30, 30 from the core winding body 37, each leg 32a, 32b may be cut at two locations as shown by line H' in Figure 16(b), and the winding may be performed so that the start and end of the strip-shaped electromagnetic steel sheet 35b are located on the side of the scrap material 38a that will be cut off in Figure 16(b) described later.

[0093] The core wound body 37 obtained as described above has a rounded rectangular shape similar to an oval, in which the short sides 51, 51 of the winding jig 50 are arc-shaped or linear peripheral surface portions 31, 31, and the rounded corners at both ends of the peripheral surface portions 31, 31 are connected by parallel legs 32a, 32b.

[0094] Next, the obtained bottom side 51 is welded 34 to the core wound body 37 at the center of the short sides 51, 51 in the thickness direction as shown in FIG. 16(a), to integrate the wound electromagnetic steel sheets 35b together (welding step).

[0095] The core wound body 37 produced as described above has low performance in various aspects, such as magnetic properties, and the electromagnetic steel sheet 35b itself has a spring property that allows it to return to its original shape when bent, so that the core wound body 37 opens up into a shape close to a ring when removed from the winding jig 50. For this reason, the core wound body 37 is subjected to a heat treatment (heat treatment step).

[0096] The heat treatment can be performed by placing the core wound body 37 in a heat treatment furnace while it is still wound around the winding jig 50. The heat treatment is preferably performed by annealing the core wound body 37 at 750°C to 850°C for at least one hour. Annealing improves various performance characteristics of the core wound body 37, such as magnetic properties. Furthermore, the shape of the core wound body 37 is fixed in the wound state, as shown in FIG. 16(b). That is, even if the core wound body 37 is removed from the winding jig 50 after the heat treatment step, the shape is maintained without being distorted. The core component 30 is not subsequently subjected to a varnish impregnation process.

[0097] Next, the core wound body 37 is removed from the winding jig 50, and the legs 32a, 32b are cut at the locations indicated by dotted lines H in FIG. 16(b) to obtain the core component 30 in its final shape (cutting step). Cutting can be performed by laser cutting, wire cutting, or cutting with a grindstone. As a result, two core components 30, 30 are obtained, as shown in FIG. 16(c). Each core component 30, 30 has a parallel U-shape, with two parallel legs 32a, 32b whose tips 33, 33 are spaced apart by W1, and an arc-shaped peripheral surface 31 connecting the legs 32a, 32b.

[0098] This completes the winding method. In the case of the winding method of this embodiment, when cutting along line H in FIG. 16(b), the yield is nearly 100%, which is effective in saving resources. On the other hand, when cutting along line H', scrap material is produced, so the yield is about 90%. However, even with this, a higher yield can be achieved compared to conventional die cutting.

[0099] <Stator assembly> The obtained core part 30 is fitted with a cylindrical coil 60 as shown in FIG. 10, and the stator 10 is assembled.

[0100] <Core component preparation steps> First, a specified number of core parts 30 are prepared by bending or winding. In the case of the stator 10 of Fig. 1, there are 12 core parts 30. The core part 30 has a parallel U-shape with parallel legs 32a and 32b.

[0101] <Cylindrical coil manufacturing steps> Also, a specified number of cylindrical coils 60 are prepared. The cylindrical coils 60 are formed by winding a covered wire 61 into a cylindrical shape as shown in Fig. 1 and Fig. 10. Preferably, the covered wire 61 is wound into a cylindrical shape having an inner diameter that fits into the adjacent leg portions 32b, 32a when the two core parts 30a, 30b are arranged side by side, specifically, an inner diameter of a substantially rectangular ring shape.

[0102] As shown in Fig. 2, the cylindrical coil 60 is preferably formed by winding a covered wire 61 in layers so that the number of turns in the axial direction perpendicular to the winding direction gradually increases. This is to increase the space factor of the stator 10. The covered wire 61 is preferably an enamel-coated copper wire, but this does not exclude the use of a covered aluminum wire or the like for weight reduction and cost advantage.

[0103] 2, the cylindrical coil 60 is preferably formed by winding a coated wire 61 in multiple layers around a bobbin 62 molded from an electrically insulating resin or the like. The bobbin 62 has a winding tube portion 63 having an inner diameter that fits into adjacent leg portions 32b, 32a when the two core parts 30a, 30b are arranged side by side, and flange portions 64a, 64b that protrude outward from both ends of the winding tube portion 63. When the flange portions are inserted into the legs 32b, 32a, the flange portion 64a that faces the circumferential surface portion 31 protrudes outward more than the other flange portion 64b, allowing for a larger number of windings to be applied.

[0104] <Parallel steps> First, the two core parts 30a, 30b are arranged so that the legs 32b, 32a are adjacent to each other as shown in Fig. 10(a). In this embodiment, the core part 30 is originally parallel U-shaped, so there is no need to apply a biasing force in the direction of arrow A in Fig. 5 to spread the legs 32a, 32b apart, as in the first embodiment.

[0105] <Starting cylindrical coil installation step> As shown in Figure 10(b), the cylindrical coil 60a is fitted to the leg 32a (leftmost) that serves as the starting end of the core part 30a (the left end in the figure). Note that the starting cylindrical coil 60 may be wobbly because it is fitted to one leg 32a. For this reason, this step of fitting the starting cylindrical coil may be performed before, after, or simultaneously with the step of fitting the terminal cylindrical coil 60l.

[0106] <Cylindrical coil installation step> Next, as shown in Figures 10(c) and 10(d), the cylindrical coil 60b is fitted into the adjacent legs 32b, 32a of the core parts 30a, 30b. As shown in Figure 11, the legs 32a, 32b of the core parts 30a, 30b are parallel to each other and the distance between the tips 33, 33 is W1, so even if the cylindrical coil 60 has a gradually increasing number of windings, it can be fitted into the adjacent legs 32b, 32a without hitting each other.

[0107] <Insertion step> The above-described arranging step and cylindrical coil attachment step are repeated to sequentially add core parts 30c, 30d, ..., 30k, and attach cylindrical coils 60c, 60d, ..., 60k, as shown in Figures 10(d) and 10(e). Then, with the number of core parts 30a to 30k that is one less than the specified number arranged in parallel, the last cylindrical coil 60l is fitted onto leg 32b of core part 30k, which is the final core part.

[0108] Next, the core parts 30a to 30k are formed into a generally annular shape as shown in Fig. 17. Specifically, an external force is applied in the direction of arrow G to each of the core parts 30a to 30k so that the distance between the tips 33, 33 narrows to W from the parallel U-shape as shown in Fig. 13(a), and the core parts 30a to 30k are formed into a narrow U-shape as shown in Fig. 13(b), thereby forming the core parts 30a to 30k into a generally annular shape.

[0109] To form the core parts 30a-30k into a generally annular shape, the core parts 30a-30k are inserted into an outer mold 70 having a flattened annular inner surface as shown in FIG. 17. The outer mold 70 shown in the figure has an elliptical inner surface with its center at O, and the core parts 30a-30k and the cylindrical coils 60a-60l are arranged so that the adjacent portions D of the cylindrical coils 60a and 60l, which are the starting and ending ends, are located at the vertex E on the minor axis side of the outer mold 70. This results in the core parts 30a-30k and the cylindrical coils 60a-60l having a flattened elliptical shape. The cross section of each core part 30 and the inserted cylindrical coil 60 is as shown in FIG. 2.

[0110] In addition, the outer mold 70 may have a hinge structure on the side of the vertex E' on the short axis side opposite the vertex E on the short axis side, and the core parts 30a to 30k and the cylindrical coils 60a to 60l may be arranged on the open outer mold 70, and the outer mold 70 may be closed to form the shape shown in Figure 17.

[0111] In this state, the last core part 30l is pushed in the direction of arrow F while maintaining the parallel U-shape as shown in Figure 17, and the legs 32b, 32a of the core part 30l are inserted into the starting and ending cylindrical coils 60a, 60l. This connects all of the core parts 30a to 30l and the cylindrical coils 60a to 60l in a ring shape.

[0112] <Molding step> Finally, by molding the connected core parts 30a to 30l and the tubular coils 60a to 60l into a circular shape, as shown in Figure 1, the stator 10 is obtained in which the core part 30 has a circumferential surface portion 31 that forms a circular outer periphery, and the leg portions 32b, 32a of adjacent core parts 30, 30 function as teeth and the tubular coils 60 are fitted into each other.

[0113] As described above, according to the present invention, parallel U-shaped core parts 30 are lined up and cylindrical coils 60 are sequentially attached to obtain an annular stator 10. Stator 10 may be mechanically fixed in shape by varnish impregnation, adhesive, resin molding, or the like, as needed, within a shape range that ensures free rotation of the rotor, thereby suppressing beat noise caused by magnetostrictive vibration of the electromagnetic steel sheet, and improving environmental resistance, such as rust prevention, uniform temperature distribution, and moisture resistance.

[0114] The obtained stator 10 can be used as a motor by, for example, mounting it in a resin housing and rotatably mounting a rotor with permanent magnets arranged in an annular shape on the inner periphery.

[0115] As shown in FIG. 2 , the stator 10 of the present invention, like the first embodiment, can fit a bobbin 62 with gradually increasing numbers of turns of covered wire 61 on the peripheral surface 31 side into the legs 32a, 32b. Although this slightly reduces magnetic properties compared to the first embodiment, it facilitates insertion of the cylindrical coil, facilitates automation using equipment, and reduces the non-winding space 65 (where no covered wire 61 is present) within the core component 30, thereby contributing to an improved cylindrical coil space factor. The reduced non-winding space 65 can be confirmed by comparing it with the conventional non-winding space 105 shown in FIG. 18( c). Because the non-winding space 65 of the stator 10 of the present invention is smaller than the conventional non-winding space 105, the space factor of the cylindrical coil can be increased by approximately 5% to 15%. The increased space factor reduces winding resistance, copper loss, and suppresses coil temperature increases, thereby improving motor efficiency.

[0116] The above description is for the purpose of explaining the present invention, and should not be construed as limiting the invention described in the claims or narrowing its scope. Furthermore, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications are possible within the technical scope described in the claims. [Explanation of symbols]

[0117] 10 Stator 12 stator core 30(30a-30l) Core parts 31 Peripheral part 32a Legs 32b Legs 34 Welding 35(35a,35b) Electrical steel plate 36 Core Block 37 Core winding body 40 Heat treatment jig 50 Winding jig 60(60a-60l) cylindrical coil 62 Bobbin

Claims

1. an electromagnetic steel sheet preparation step of preparing a plurality of electromagnetic steel sheets whose lengths are adjusted so that their tips become flat after bending; a lamination step of laminating the electromagnetic steel sheets in order of length so that the central portions thereof are linear; a welding step of welding the central portions of the stacked electromagnetic steel sheets in a thickness direction to obtain a core block in which the electromagnetic steel sheets are integrated; a bending step of bending the core block into a substantially U-shape toward the shortest electromagnetic steel plate; and a heat treatment step of annealing the core block in a bent state; Including, Manufacturing method for motor core parts.

2. the bending step is a step of bending the core block into a substantially U-shape having two legs on both sides and an arc-shaped peripheral surface portion connecting the legs, and the legs are bent so that the distance between the legs on the tip side becomes narrower. The method for manufacturing the motor core component according to claim 1 .

3. the bending step is a step of bending the core block into a substantially U-shape having two legs on both sides and an arc-shaped peripheral surface connecting the legs, and bending the legs so that the legs are parallel to each other. The method for manufacturing the motor core component according to claim 1 .

4. The heat treatment step is performed by mounting the core block bent into a substantially U-shape on a heat treatment jig that holds the core block in a bent state. A method for manufacturing the motor core component according to any one of claims 1 to 3.

5. a winding step of winding the strip-shaped electromagnetic steel sheet around a winding jig having a circular arc-shaped bottom to obtain a core wound body; a welding step of welding the bottom side of the core wound body in the thickness direction; a heat treatment step of annealing the core winding; and a cutting step in which two sides of the heat-treated core wound body sandwiching the bottom side are cut so that the tips are flat, thereby forming a substantially U-shaped body having two leg portions on both sides and an arc-shaped peripheral portion connecting the leg portions; Including, Manufacturing method for motor core parts.

6. The winding jig is an isosceles triangle with a rounded corner and an arc-shaped base. The method for manufacturing the motor core component according to claim 5 .

7. The winding jig is a rounded rectangle with an arc-shaped base. The method for manufacturing the motor core component according to claim 5 .

8. a core part preparation step of preparing a specified number of core parts manufactured by the manufacturing method of claim 2 or 6, the number of which will form a ring when arranged with the peripheral surface portion on the outer periphery side; a cylindrical coil fabrication step of fabricating the specified number of cylindrical coils by winding a coated wire in multiple layers so that the number of windings gradually increases in an axial direction perpendicular to the winding direction, the cylindrical coil having an inner diameter that fits into the adjacent leg portions when the two core parts are arranged side by side; an arranging step of applying a biasing force in an opening direction of the core part so that the legs are parallel, and then applying a biasing force to the adjacent core part in the same manner to open the core part so that the legs are parallel, and arranging the opened core parts so that the legs are adjacent to each other; a starting end cylindrical coil mounting step of fitting the cylindrical coil into a core part located at the starting end; a cylindrical coil mounting step of fitting the cylindrical coil onto the adjacent leg portions of the parallel-arranged core parts from the side having the larger number of windings; an insertion step of repeating the juxtaposition step and the cylindrical coil attachment step, juxtaposing the core parts one less than the specified number, attaching the cylindrical coil, and then releasing the urging force applied to the core parts, connecting the core parts one less than the specified number with the cylindrical coil to form a ring shape, fitting the cylindrical coil into the core part located at the end, inserting the last core part into the cylindrical coils at the start and end while applying the urging force so that the legs are parallel, and after insertion, releasing the urging force, causing the core parts to return to their original state by a restoring force so that the spacing at the tip ends of the legs becomes narrower; Including, Stator manufacturing method.

9. In the inserting step, the last core part is inserted into the core parts connected by the cylindrical coils to form an annular shape, with the adjacent portions of the cylindrical coils at the start and end points positioned at the apex of the short axis of the ellipse. The method for manufacturing a stator according to claim 8.

10. The cylindrical coil is wound around a bobbin having a winding tube portion with an inner diameter that fits into the adjacent leg portion when the two core parts are arranged side by side, and flange portions that protrude outward from both ends of the winding tube portion, and one of the flange portions, one of which has a gradually increasing number of windings, is longer than the other. The method for manufacturing a stator according to claim 8.

11. The step of attaching the starting cylindrical coil is performed before, after, or simultaneously with the step of fitting the terminal cylindrical coil in the insertion step. The method for manufacturing a stator according to claim 8.

12. a core part preparation step of preparing a specified number of core parts manufactured by the manufacturing method of claim 3 or 7, the number of which will form a ring when arranged with the peripheral surface portion on the outer periphery side; a cylindrical coil fabrication step of fabricating the specified number of cylindrical coils by winding a coated wire in multiple layers so that the number of windings gradually increases in an axial direction perpendicular to the winding direction, the cylindrical coil having an inner diameter that fits into the adjacent leg portions when the two core parts are arranged side by side; an arranging step of arranging the core parts next to each other so that the legs are adjacent to each other; a starting end cylindrical coil mounting step of fitting the cylindrical coil into a core part located at the starting end; a cylindrical coil mounting step of fitting the cylindrical coil onto the adjacent leg portions of the parallel-arranged core parts from the side having the larger number of windings; an insertion step of repeating the juxtaposition step and the cylindrical coil attachment step, juxtaposing the core parts one less than the specified number, attaching the cylindrical coil, and then applying an external force to narrow the spacing at the tip ends of the legs of the core parts, connecting the core parts one less than the specified number with the cylindrical coil to form a ring shape, fitting the cylindrical coil into the core part located at the end, and inserting the last core part into the cylindrical coil at the start and end while applying a biasing force so that the legs are parallel; a molding step of applying an external force to narrow the gaps between the tip ends of all the core parts, thereby forming the core parts and the cylindrical coil into an annular shape; Including, Stator manufacturing method.

13. In the inserting step, the last core part is inserted into the core parts connected by the cylindrical coils to form an annular shape, with the adjacent portions of the cylindrical coils at the start and end points positioned at the apex of the short axis of the ellipse. The method for manufacturing a stator according to claim 12.

14. The cylindrical coil is wound around a bobbin having a winding tube portion with an inner diameter that fits into the adjacent leg portion when the two core parts are arranged side by side, and flange portions that protrude outward from both ends of the winding tube portion, and one of the flange portions, one of which has a gradually increasing number of windings, is longer than the other. The method for manufacturing a stator according to claim 12.

15. The step of attaching the starting cylindrical coil is performed before, after, or simultaneously with the step of fitting the terminal cylindrical coil in the insertion step. The method for manufacturing a stator according to claim 12.

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