JP6581848B2 - Manufacturing method of coil for coreless motor - Google Patents

Description

  The present invention relates to a method for manufacturing a coil used in, for example, a coreless motor.

  Conventionally, coils having various shapes have been manufactured, and various coil manufacturing methods have been proposed. For example, a coil manufacturing method in which a saddle coil is inserted into a press die and compression molding is performed has been proposed (see Patent Document 1). In this patent document, a coil wound in an aligned manner on a winding frame is compression-molded by a molding piece divided from four directions with respect to the coil cross section so that the coil has a substantially square cross section and has a high winding space. Ensuring rates is disclosed.

  However, such a conventional coil manufacturing method compresses the cross-sectional shape of the coil, and does not compress the entire shape of the coil.

  On the other hand, in recent years, a coreless motor without an iron core has been provided in the market. Coreless motors generally do not have an iron core, so the rotor is light and the moment of inertia is small, so the response is good, and pulsation torque (cogging torque) is generated by the magnetic attraction generated between the iron core and the magnet. Therefore, motor vibration and noise are reduced.

  Here, the coreless motor has a structure in which the effective portion of the coil is arranged in a substantially cylindrical shape. In the coil arranged in this cylindrical shape, the conducting wire needs to be arranged in the axial direction, not in the circumferential direction. For this reason, it becomes a problem how the end portions of the conductive wires arranged in the axial direction are processed.

  As a specific shape, for example, a heat conduction stator support structure is proposed that has a coil in which the conductive wire is neatly aligned and arranged in a cylindrical part that is an effective part by bending the end of some coils to the outside of the coil. (See Patent Document 2).

  However, this coil structure has a problem in that it requires a space for arranging the conductive wire outside the effective portion having a cylindrical shape, resulting in an increase in size.

  Here, it is conceivable to reduce the size of the coil by bending the end portion of the effective portion of the conducting wire to the inside of the cylindrical shape.

  However, if it is such a shape, the square shape of the coil must spread greatly from one opening to the other opening.

  Such a shape cannot be manufactured simply by winding a coil around a mold having a desired shape, and there is a problem that it cannot be manufactured due to deformation due to deformation by press molding as in Patent Document 1. It was.

JP-A-9-168261 JP 2005-518777 A

  In view of the above problems, an object of the present invention is to provide a method for manufacturing a coil for a coreless motor that manufactures a coil having a shape that cannot be manufactured by a conventional manufacturing method.

The present invention includes a winding step in which a conducting wire is wound around a winding jig to form a first coil shape, and the first coil-shaped conducting wire detached from the winding jig is formed into a second coil shape by a forming jig. The winding jig has a three-dimensional shape whose inner dimension continuously increases from one end where winding of the conducting wire is started to the other end where winding of the conducting wire is completed, or the inner dimension is continuously reduced. It has a three-dimensional shape, and the forming jig includes an insertion member that is inserted inside the first coil-shaped conductor and a covering member that covers the first coil-shaped conductor. In the forming step, the first coil-shaped lead wire is sandwiched between the insertion member and the covering member and press-molded, and the insert member has a small inner dimension of the first coil-shaped lead wire. A projecting portion that is inserted through the opening of the projecting portion and a circular arc portion having a constant width that extends symmetrically from the base portion of the projecting portion, and the covering member contacts the concave portion that houses the projecting portion and the arc portion. It is a manufacturing method of the coil for coreless motors which has the shape which has the circular part of the same width | variety which touches or adjoins, or the substantially same width .

  According to the present invention, a coil having a shape that cannot be manufactured by a conventional manufacturing method can be manufactured.

The block diagram which shows the whole structure of the coreless motor by this invention. The disassembled perspective view which shows a part of coreless motor. The block diagram which shows the shape of a coil. Explanatory drawing explaining the winding jig | tool of a coil, and a winding process. The block diagram which shows the shape of a 1st shaping | molding jig | tool. Explanatory drawing explaining the process of press-molding with a 1st shaping | molding jig. Explanatory drawing explaining the process of press-molding with a 2nd shaping | molding jig.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows an overall configuration of a coreless motor 1 according to an embodiment of the present invention with a housing removed, FIG. 1 (a) shows a perspective view, and FIG. 1 (b) shows a plan view. . FIG. 2 is a partially exploded perspective view showing the plurality of coils 8 and the rotor 2.

  The coreless motor 1 according to the present embodiment includes a rotor 2 having a substantially cylindrical shape as a whole and a stator 3 containing the rotor 2 in a state of being separated from the rotor 2, and is housed in a cylindrical housing (not shown). Yes.

The rotor 2 includes a substantially cylindrical magnet yoke 4, a shaft 5 inserted through a through hole provided in the center of the magnet yoke 4 and fixed to the magnet yoke 4, and a magnet yoke 4 disposed radially outward of the magnet yoke 4. And a magnet group 6 having a substantially cylindrical shape formed coaxially with the shaft 4 and provided rotatably about the shaft 5. The magnet group 6 is configured such that four arc-shaped magnets are arranged in a non-contact manner so as to form a circle. Each magnet of the magnet group 6 is configured as a quadrupole magnet in which N poles and S poles are alternately arranged in the circumferential direction.

  The stator 3 is arranged so as to be slightly separated (or abutted) so as to cover the outer periphery of the rotor 2. As shown in FIG. 2, the stator 3 includes coils 8 a, 8 b, and 8 c constituting the first coil group 7 </ b> A that is first inserted into the rotor 2, and then a second coil group 7 </ b> B that is subsequently inserted into the rotor 2. Coil 8d, 8e, 8f.

  The side portions of the coils 8 constituting the first coil group 7A and the side portions of the coils 8 constituting the second coil group 7B are alternately arranged on the circumference of the rotor 2. That is, the coils 8a, 8d, 8b, 8e, 8c, and 8f are arranged on the circumference of the rotor 2 in this order.

  FIG. 3 is a configuration diagram showing the shape of the coil 8. FIG. 3 (a) is a perspective view showing the plan and the back, FIG. 3 (b) is a plan view, FIG. 3 (c) is a rear view, and FIG. ) Shows a right side view.

  The coil 8 is formed in a deformed box frame shape by winding a conducting wire 10 having a uniform thickness over the entire length. The coil 8 will be described in detail. The coil 8 is arranged so that the top wall 9h and the bottom wall 9i of the shape in which the arcuate conductors 10 are aligned in the radial direction without gaps are parallel to each other, and the top surface It has a shape in which two side walls 9f and 9g that are bent at right angles from the respective side end portions of the wall 9h and the bottom wall 9i are arranged. The side walls 9 f and 9 g have a circular cross section in the horizontal direction, and the arcuate curvature is the curvature along the side circumferential surface of the rotor 2.

  The coil 8 has a space portion 9d therein, and an opening portion 9a is formed radially inside the top wall 9h and the bottom wall 9i, and an opening portion 9b is formed radially outside. The openings 9a and 9b have an arcuate portion constituted by the ends of the top wall 9h and the bottom wall 9i and a straight portion constituted by the edges of the side walls 9f and 9g, and the opening 9a is open. The area is smaller than that of the portion 9b. The coil 8 is formed so that the sectional area of the coil 8 continuously decreases from the opening 9b to the opening 9a. When the coil 8 is inserted into the rotor 2, the peripheral edge 2b of the rotor 2 is inserted from the opening 9b that is largely open, passes through the space 9b, and is exposed from the opening 9a.

  The four side portions 9e formed at both ends of the top wall 9h and the bottom wall 9i and the side walls 9f and 9g connected to the respective corner portions 9e have arcuate shapes that protrude outward, respectively. 3 is a side forming a part of the circumference of the substantially cylindrical shape.

  The coil 8 having such a shape is formed by winding a conducting wire 10 having a uniform thickness over the entire length.

  As shown in FIGS. 1 and 2, a substantially cylindrical coil yoke 30 is provided coaxially with the rotor 2 so as to cover the stator 3 outside the stator 3 in the radial direction.

  As described above, the coils 8a, 8b, 8c, 8d, 8e, and 8f are arranged at equal intervals in the circumferential direction. At this time, the rotor 2 and each coil 8 are arranged at intervals, the first coil group 7A, that is, the coils 8a, 8b, and 8c are arranged at intervals, and the second coil group 7B, that is, The coils 8d, 8e, and 8f are arranged at intervals, and are kept in a non-contact state (or a contact state).

  More specifically, three coils 8 are arranged at intervals of 120 ° around the axis of the rotor 2 to constitute the first coil group 7A. Three coils 8 are further mounted at positions shifted by 60 ° about the axis of the rotor 2 with respect to the first coil group 7A. The three coils 8 constitute a second coil group 7B. The first coil group 7A and the second coil group 7B constitute the stator 3.

  Each coil 8 is arranged at equal intervals in the circumferential direction along the outer peripheral surface 2 a of the rotor 2 so as to cover the substantially cylindrical rotor 2. Each coil 8 is arranged so that its outer periphery forms one circle in a plan view when combined. That is, the radii d1 from the center P of the shaft 5 to the corners 9e of each coil are all arranged to have the same length.

  In the stator 3, an upper wall 7 s constituted by the upper surface wall 9 h of the coil 8 and a bottom wall 7 t constituted by the bottom wall 9 i of the coil 8 are parallel to each other, and each is perpendicular to the shaft 5. Configured as follows. A side wall 7u constituted by the side walls 9f and 9g of the coil 8 is provided to stand vertically from the bottom wall 7t, and further bends at a right angle to continue to the upper wall 7s.

  The circumferential widths w1 of the coils 8 constituting the side wall 7u of the stator 3 are all the same length, and the circumferential widths w2 between the coils 8 are all the same length. The width w2 is a length of 1/10 or less of the width w1.

  The second coil group 7B, which is a part of the stator 3, has a height h2 of each coil 8 so that one end 9c of each adjacent coil 8 of the first coil group 7A can be inserted. It is formed slightly longer than the height h1 of each coil 8 of the first coil group 7A.

  As described above, the stator 3 has a double structure composed of the first coil group 7A and the second coil group 7B, but as described above, the first coil group 7A, The coil group 7B is arranged so that its outer periphery forms one circle in a plan view in a state where the coils 8 are combined, so that it is compactly accommodated in the housing without generating useless space. Can do. Thereby, the coreless motor 1 can be reduced in size and weight.

  Further, in a state where the coils 8 are combined, the outer periphery of the coils 8 is arranged so as to form one circle in a plan view, so that the interval between the coil 8 and the coil yoke 30 can be narrowed, and the torque is increased. And can be controlled with high accuracy.

  In this embodiment, the number of the coils 8 is six. However, the number of the coils 8 may be an even number, for example, eight.

  Next, the manufacturing method of the coil 8 for coreless motor 1 mentioned above is demonstrated. The coil 8 is manufactured by winding a conductive wire 10 around a winding jig 11 to form a first coil shape, and forming a first coil-shaped conductive wire 12 removed from the winding jig 11 with a forming jig. And a molding step of press molding into a coil shape.

[Jig used for winding process]
FIG. 4 is a diagram for explaining the winding process of the coil 8. FIG. 4A shows a winding jig 11 used for winding the conductive wire 10 into a coil shape. The winding jig 11 includes a winding portion 11a having a substantially conical shape (a divergent shape or a cone shape) having a diameter (inner dimension) continuously increasing from an upper portion (base portion) toward a lower portion (end portion), and a winding portion 11a. And a columnar anti-slip portion 11b erected on the upper end of the head. The winding jig 11 has an outer peripheral surface that is approximately the same as or slightly larger than the inner surface of the coil 8.

  The anti-slip portion 11b may be a square such as a square or a rectangle. In this case, a shape close to a square is preferable, and the difference between the long side and the short side can be 50% or less, preferably 25% or less, and more preferably 10% or less.

  In addition, the winding jig 11 is not limited to a conical shape, and may have an appropriate shape such as a quadratic thrust shape in which the cross-sectional area gradually increases from the base side where the anti-slip portion 11b is provided to the opposite end side. it can.

  The winding portion 11a of the winding jig 11 may have a substantially conical shape in which the diameter (inner dimension) continuously decreases from one end portion where the conducting wire 10 is wound to the other end portion where the conducting wire 10 is finished being wound.

[Winding process]
As shown in FIG. 4B, in the winding step, first, the substantially central portion 10a of the conducting wire 10 is applied to the upper portion of the winding portion 11a, and the left conducting wire 10b is placed along the outer peripheral surface 1c of the winding jig 11. Wrap evenly. At this time, the anti-slip portion 11b prevents the lead wire 10 from being displaced, so that the lead wire 10 can be wound without the position of the winding start portion being displaced.

Next, as shown in FIG. 4 (c), the right conducting wire 10c is overlapped and wound around the radially outer side of the left conducting wire 10b portion that has already been wound.
Then, as shown in FIG. 4 (d), the left conductive wire 10 b is doubly wound on the right conductive wire 10 c, and the conductive wire 12 serving as the prototype of the coil 8 is formed.

  After winding in this way, when the conducting wire 12 is pulled out from the winding jig 11, the inner dimension gradually increases from one end (base) to the other end (end) as shown in FIG. 2 (conical shape, substantially conical shape in the illustrated example), and a two-layered coil-shaped conductive wire 12 (first coil-shaped conductive wire) in which the conductive wire 10 is double-wrapped in the radial direction. can get.

  Further, by starting winding from the substantially central portion 10a of the conducting wire 10, both the left (one) end portion 10d and the right (other) end portion 10e of the conducting wire 10 are positioned at the bottom portion 12a of the coil-shaped conducting wire 12. Therefore, operation becomes easier when wiring.

  In addition, winding of the conducting wire 10 may be implemented in order from one of the left and right as described above, or both may be performed simultaneously. When both are performed simultaneously, the manufacturing time can be shortened.

[Jig used for the first molding process]
Next, a molding process in which the first coil-shaped lead wire 12 removed from the winding jig 11 is press-molded into a second coil shape by the molding jig will be described.

  FIG. 5 shows the shape of the first forming jig 13, FIG. 5 (a) is a front view, FIG. 5 (b) is a right side view, and FIG. 5 (c) is an AA sectional view. . The first forming jig 13 covers the insertion member 14 inserted into the first coil-shaped conductor 12 and the first coil-shaped conductor 12 into which the insertion member 14 is inserted from above. And a covering member 15 to be fitted.

The insertion member 14 includes a substantially cylindrical columnar portion 16 and a substantially quadrangular prism-shaped protruding portion 17 that protrudes radially outward from a part of the peripheral side surface 16 a of the cylindrical portion 16. Both end surfaces other than the peripheral side surface 16a of the insertion member 14 are formed in parallel and smooth planes.
The insertion member 14 is provided with a tightening screw through-hole 16c penetrating from the upper surface 17a of the projecting portion 17 to the bottom portion 16b of the cylindrical portion 16 to form a female screw.

  A radius d2 of the cylindrical portion 16 is formed to have a length that is substantially the same as an inner peripheral radius when the plurality of coils 8 are combined into a substantially cylindrical shape, that is, a size that is the same as or slightly larger than the size of the outer periphery of the rotor 2. As a result, the portions that are press-molded into the outer peripheral shape of the cylindrical portion 16 become both side walls 9f, 9g of the coil 8, so that the outer periphery forms one circle in plan view when the coils 8 are combined. Can be placed.

  The protruding portion 17 is formed to have the same thickness as the axial direction of the cylindrical portion 16, and has the same plane as both flat end surfaces of the cylindrical portion 16. As shown in FIG. 5C, the cross-sectional shape 17b perpendicular to the axial direction of the protrusion 17 is such that the opening 9a of the coil 8 is in the direction from the opening 9a to the opening 9b (the back surface shown in FIG. 3C). It is formed in the same shape as seen in the viewing direction. The length w3 in the width direction and the length w4 in the thickness direction of the cross-sectional shape 17b are substantially the same length. Thereby, the shape of the inner opening 9a of the coil 8 can be adjusted.

  The length w4 in the thickness direction of the protrusion 17 is slightly longer than twice the width of the side walls 9f and 9g of the coil 8. Thereby, two side walls 9f and 9g of another coil 8 can be arranged in the opening 9a in the coil 8 after molding. The length w4 of the protruding portion 17 in the thickness direction can be set to 1 or more times the width of the coil 8 (width of the side walls 9f and 9g) or the thickness of the cylindrical portion 16, and is preferably set to 2 or more times. . Further, the length w4 in the thickness direction of the protruding portion 17 can be less than 5 times the width of the coil 8 (width of the side walls 9f and 9g) or the thickness of the cylindrical portion 16, and can be less than 4 times. Preferably, it is less than 3 times, more preferably less than 2.5 times.

  The covering member 15 has a shape having a fitting concave portion 19 (concave portion) into which the insertion member 14 is fitted on one side surface of a cube having the same thickness as the axial thickness of the insertion member 14. The fitting recess 19 has a flat surface portion 19a in which the protrusion portion 17 of the insertion member 14 is fitted in the central portion, and a flat surface in which the side surfaces of the protrusion portion 17 are in contact with or close to each other vertically from both ends of the flat surface portion 19a. Portions 19b and 19c are provided. The curved surface portions 19d and 19e (the arc portions of the covering member 15), which are connected to the flat portions 19b and 19c and the upper portion of the cylindrical portion 16 of the insertion member 14 (the portion continuing from the protruding portion 17) are fitted, respectively, of the flat portion 19a. Provided on both sides.

  The covering member 15 is provided with a fastening screw insertion hole 15a at the center of the upper surface. The tightening screw 18 is screwed into the screw insertion hole 15a and the screw through hole 16c in a state where the insertion member 14 and the covering member 15 are fitted, and the insertion member 14 and the covering member 15 are coupled and further tightened. Thus, the first coil-shaped lead wire 12 is sandwiched between the insertion member 14 and the covering member 15 and press-molded.

[First shaping process]
FIG. 6 is a diagram illustrating a process of press-molding the first coil-shaped lead wire 12 in the downward direction F <b> 1 (the proximity direction of the insertion member 14 and the covering member 15) with the first forming jig 13. The first coil-shaped conductor 12 is pressed to be formed into an intermediate coil-shaped conductor 20.

  More specifically, the insertion member 14 is inserted through the first coil-shaped conductor 12 so that the protruding portion 17 is exposed from one opening 12c of the first coil-shaped conductor 12. At this time, the conducting wire 12 is attached to the insertion member 14 so that the winding start portion 12 b is positioned at the boundary portion 17 c between the protruding portion 17 and the cylindrical portion 16. In this state, the lead wire 12 is sandwiched between the insertion member 14 and the covering member 15 and press-molded, so that a part of the opening 9a of the coil 8 (two opposite sides) is shaped into a side surface of the cross-sectional shape 17b of the protrusion 17 (FIG. 5). The side walls 9f and 9g (see FIG. 3) that can be molded in the same manner as the side surface having the length w4 in the thickness direction (c) and in which the alignment direction of the conductors 12 is curved along the peripheral side surface of the insertion member 14. ) Can be formed.

[Jig used for the second shaping process]
FIG. 7 is a diagram for explaining a step of press molding with the second molding jig 21. FIG. 7A shows the step of press molding, and FIG. 7B shows the coil 8 press-molded into the second coil shape 25.

  As shown in FIG. 7A, the second forming jig 21 includes a base 22 and a pair of dies 23 and 24. The dies 23, 24 are formed so that the pressing surface 23a and the pressing surface 24a, which are opposite surfaces, are parallel and smooth, and larger than the size of the state in which the insertion member 14 and the covering member 15 are combined. Therefore, the insertion member 14 and the covering member 15 that are joined together with the conductor 12 sandwiched therebetween can be sandwiched between the dies 23 and 24.

[Second shaping step]
In the second shaping step, the intermediate coil-shaped lead wire 20 attached to the first forming jig 13 is then press-formed by the second forming jig 21.

  More specifically, the first forming jig 13 to which the intermediate coil-shaped conductive wire 20 is attached is placed between the pair of dies 23 and 24 and fixed to the base 22. The pair of dies 23 and 24 are slid toward each other toward the intermediate coil-shaped conductive wire 20. The intermediate coil-shaped conductive wire 20 is pressed from both sides F2 and F3 in the thickness direction by a pair of dies 23 and 24 to be formed into a second coil shape 25.

  Accordingly, the intermediate coil-shaped lead wire 20 is sandwiched between the curved surface portions 19d and 19e (see FIG. 5A) of the first forming jig 13 and the peripheral side surface 16a, and the pressing surface 23a of the die 23. And the pressing surface 24a of the die 24 are pressed from both sides, and the flat front wall 9h and back wall 9i of the coil 8 are formed. The four corner portions that are in pressure contact with the curved surface portions 19d and 19e and the pressing surfaces 23a and 24a become arc-shaped corner sides 9e of the coil 8 that is a deformed box frame type. In this way, the intermediate coil-shaped conductive wire 20 is press-molded into the second coil shape 25, and the coil 8 is manufactured.

FIG. 7B shows the coil 8 that is press-molded into the second coil shape 25.
The shape of the opening 9a is such that one end 9c of each coil 8 adjacent to each other can be inserted and held as shown in FIG. As a result, when a plurality of coils 8 are combined into a substantially cylindrical shape, the end 9c can be inserted and held in the opening 9a.

  In addition, in this embodiment, it shape | molded in two steps, a 1st shaping | molding process and a 2nd shaping | molding process, However, You may perform a 1st shaping | molding process and a 2nd shaping | molding process simultaneously.

The stator 3 having the shape shown in FIG. 1 can be manufactured by the above manufacturing method.
In this manufacturing method, after first winding the winding jig 11 to form a primary shape coil, the first shaping jig 13 and the second shaping jig 21 are used to shape the coil. The coil 8 having a lean shape that can be mounted so as to cover the rotor 2 in a three-dimensional shape whose inner dimension continuously increases or decreases can be formed.

  In addition, the first forming jig 13 is formed by pressing the first coil-shaped lead wire 12 between the insertion member 14 and the covering member 15 in an arc shape, so that the arc-shaped side wall along the outer periphery of the rotor 2 is formed. 9f and 9g can be formed.

  In addition, the length w4 in the thickness direction of the protrusion 17 is slightly longer than twice the width of the side walls 9f and 9g of the coil 8, and therefore, is separately provided in the opening 9a in the coil 8 after molding. Two side walls 9f and 9g of the coil 8 can be arranged in total. Thereby, the compact stator 3 in which the side walls 9f and 9g are densely arranged on the outer periphery of the rotor 2 can be formed.

  Further, since the arc portion of the insertion member 14 (a part on both sides of the protruding portion 17 of the outer periphery of the cylindrical portion 16) is formed along a circle slightly larger than the outer periphery of the rotor 2, the coil 8 after molding is formed. In combination, the stator 3 close to the rotor 2 can be formed.

  Further, the first coil-shaped lead wire 12 sandwiched by the first forming jig 13 constituted by the insertion member 14 and the covering member 15 is pressed by the second forming jig 21 having a pair of dies 23 and 24. By molding, the shape of the opening 9a and the side walls 9f and 9g can be made surely the same, and the front wall 9h and the back wall 9i can be formed to have a certain shape.

  In addition, although the stator 3 has a double structure composed of the first coil group 7A and the second coil group 7B, the outer periphery of the stator 3 has a single circle in plan view when the coils 8 are combined. Since it arrange | positions so that it may comprise, the coreless motor 1 which can be accommodated in a housing compactly without producing a useless space can be manufactured. Moreover, since the space | interval of the coil 8 and the coil yoke 30 can be narrowed, the coreless motor 1 which has high magnetic force and can be controlled with high precision can be manufactured.

  Since the coreless motor 1 manufactured in this way is sensitive to ON and OFF reactions and can be finely controlled, it is used for a robot motor or the like.

The present invention is not limited to this embodiment, and can be various other embodiments.
For example, the cylindrical portion 16 (see FIG. 5) of the insertion member 14 is a circular arc portion that forms both side walls 9f and 9g (see FIG. 3) of the coil 8, and a smooth surface that forms the top wall 9h and bottom wall 9i of the coil 8. Since the end face is important, the cylindrical portion 16 may have an appropriate shape such as a semicircular shape in which a portion other than the circular arc portion (for example, the bottom portion 16b illustrated in FIG. 5A) is cut instead of the cylindrical shape.

  The present invention can be used for manufacturing a coreless motor used as a drive device, a power generation device, or the like.

DESCRIPTION OF SYMBOLS 1 ... Coreless motor 8 ... Coil 9a ... Opening part 9c ... One end 10 ... Conductive wire 11 ... Winding jig | tool 12 ... 1st coil-shaped conducting wire 13 ... 1st shaping | molding jig 14 ... Insertion member 15 ... Covering member 16 ... Cylindrical part 17 ... Projecting part 21 ... Second forming jig 25 ... Second coil-shaped conductor

Claims (3)

A winding step of winding a conducting wire around a winding jig to form a first coil;
Forming a first coil-shaped lead wire removed from the winding jig into a second coil shape by a molding jig;
The winding jig has a three-dimensional shape in which an inner dimension continuously increases or a three-dimensional shape in which an inner dimension continuously decreases from one end portion where winding of the conducting wire is performed to the other end portion where winding of the conducting wire is completed. And
The forming jig is composed of an insertion member that is inserted inside the first coil-shaped conductor, and a covering member that is placed on the first coil-shaped conductor.
In the molding step, the first coil-shaped lead wire is sandwiched between the insertion member and the covering member and press-molded,
The insertion member has a shape having a protruding portion that is inserted through an opening having a smaller inner dimension of the first coil-shaped conductor, and an arc portion having a constant width that extends symmetrically from a base portion of the protruding portion,
The method of manufacturing a coil for a coreless motor , wherein the covering member has a shape having a concave portion that houses the protruding portion and an arc portion having the same width or substantially the same width that is in contact with or close to the arc portion . The coreless according to claim 1 , wherein the protruding portion is formed so that a width between the circular arc portions provided symmetrically is not less than 2 times and not more than 4 times a certain width of the side wall of the coil. A method for manufacturing a motor coil. The arcuate portion, <br/> claim 1, characterized in that it is formed along a circle of substantially the same size as the inner circumference of a circle when it is used for a substantially cylindrical shape by combining a plurality of coils for coreless motor Or the manufacturing method of the coil for coreless motors of 2.

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