JP2006005999A - Device and method for molding motor coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method for molding a motor coil which realize both the higher space occupation within the slots of a motor and the compactification of a coil end. <P>SOLUTION: For this molding device, the coil end part is compressed in its radial direction, by an outer diameter molding die 41 and an inner diameter molding die 42. Moreover, while the coil end is pinched between the outer diameter molding die 44 and the inner diameter molding die 45, the coil end part is molded, being compressed in its axial direction by an axial direction molding die 43. That is, axially compressed molding is performed together with radially compressed molding. Hereby, this can compactify the entire motor by suppressing the protrusion of the motor coil without fail. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a motor coil molding apparatus and molding method. More specifically, the present invention relates to a motor coil molding apparatus and molding method that achieve both high space in a motor slot and a compact coil end portion.

  Conventionally, as a method of assembling a motor, a method of inserting a multiphase coil into a stator slot of a motor in a plurality of times is known. Furthermore, in order to increase the space factor in the stator slot, a method is known in which the coil end portion of the motor coil is formed on the outer peripheral side (hereinafter referred to as “expansion molding”) (for example, Patent Document 1). . In this method, the insertability of the motor coil to be inserted next is improved by expanding the coil end portion of the motor coil inserted in the stator slot to the outer peripheral side.

In addition, a method is known in which the coil end portion is compression-molded to increase the space factor of the coil end portion and to make the entire motor compact (for example, Patent Document 2). This method combines compression molding with a tapered outer diameter mold and compression molding with a tapered inner diameter mold.
JP 11-27889 A Japanese Patent Application Laid-Open No. 2002-272047

  However, the compression molding method described above has the following problems. That is, in the method of expanding and forming the coil end portion as disclosed in Patent Document 1, the coil end portion expands to the outer peripheral side in the radial direction, and the coil end portion is enlarged. This hinders the motor from being made compact.

  Further, when the coil end portion is compression-molded by the method disclosed in Patent Document 2, it is difficult to reduce the outer dimension of the coil end portion that is pushed out to the outer peripheral side. In other words, the coil end portion after expansion molding may not fit in the molding die. For this reason, the coil end portion cannot be reliably compressed, and instead the coil end portion may be pushed and spread. In addition, the motor coil that could not be accommodated may be damaged during compression molding. Therefore, it has been difficult to combine both technologies to achieve both high space factor in the stator slot and compact coil end.

  The present invention has been made to solve the above-described problems of the prior art. That is, an object of the present invention is to provide a motor coil molding apparatus and molding method that can achieve both a high space in the motor slot and a compact coil end portion.

  A motor coil forming method for solving this problem is a method for forming a motor coil wound around a slot of a stator core, in which the coil end portion of the motor coil is compressed in the radial direction. A first molding step of compression-molding the coil end portion so that the width of the coil end portion is narrower than the width of the final shape of the coil end portion by a pair of possible first molding dies, and compression molding in the first molding step After that, a pair of second molding dies are arranged on the radially inner diameter side and outer diameter side of the coil end portion, and in this state, the third molding die capable of compression molding the coil end portion in the axial direction. Thus, a second molding step of compression-molding the coil end portion into a final shape is included.

  That is, in the motor coil molding method of the present invention, first, the coil end portion of the motor coil is compression molded in the radial direction of the coil end portion in the first molding step. As a result, the width of the coil end portion becomes narrower than the width of the final shape of the coil end portion. Along with this, the height of the coil end portion becomes higher than the height of the final shape of the coil end portion. The final shape here is the shape of the coil end portion finally formed by this forming method, and is the shape of the coil end portion immediately after the second forming step.

  In the motor coil molding method of the present invention, after the coil end portion is compressed in the radial direction in the first molding step, the coil end portion is compressed in the axial direction in the second molding step. In this axial compression molding, the pair of second molding dies are arranged so as to face the inside and outside in the radial direction with the coil end portion interposed therebetween. That is, the coil end portion is sandwiched by the second mold. At this time, the space | interval of a 2nd shaping | molding die is equivalent to the width | variety of the final shape of a coil end part. In other words, the second mold is arranged along the edge of the final shape of the coil end portion. Note that, when the second mold is placed, the width of the coil end portion is narrower than the width of the final shape, so that the entire coil end portion can be securely sandwiched without catching the conductive wire constituting the motor coil. Then, it is compression molded into a final shape by the second mold and the third mold.

  That is, in the motor coil forming method of the present invention, the coil end portions that have spread in the outer peripheral direction in the first forming step are once collected at predetermined positions in the radial direction. In this state, compression molding is performed from the axial direction in the second molding step. Thereby, the spread in the radial direction is suppressed and the entire coil end portion is reliably compression-molded. Therefore, the coil end portion having a desired shape can be reliably formed.

  Further, in the first forming step of the present invention, it is better to form the coil end portion so that the width of the coil end portion becomes narrower as the coil end portion is separated from the stator core. If the coil end portion is formed into a tapered shape, problems such as coil hooking when the second forming die is disposed in the second forming step can be suppressed.

  The motor coil molding apparatus of the present invention is a motor coil molding apparatus for molding a coil end portion of a motor coil wound around a slot of a stator core, and is provided so as to be movable in the radial direction. A pair of first molding dies that compress the coil end portion of the coil in the radial direction, a pair of second molding dies that are arranged to face each other in the radial direction with the coil end portion interposed therebetween, and are movable in the axial direction And a third mold for compression-molding the coil end portion sandwiched between the second molds in the axial direction.

  That is, in the motor coil molding apparatus of the present invention, the coil end portion of the motor coil can be compression-molded in the radial direction of the coil end portion by the first molding die movable in the radial direction. Specifically, compression molding is performed so that the width of the coil end portion is narrower than the width of the final shape of the coil end portion. Along with this, the height of the coil end portion after compression molding becomes higher than the height of the final shape of the coil end portion. Further, in the motor coil molding apparatus, the coil end portion of the motor coil can be compression molded in the axial direction by the third mold that is movable in the axial direction. At the time of compression molding in the axial direction, the pair of second molding dies are arranged inside and outside in the radial direction with respect to the coil end portion that has been compression-molded in the radial direction. In this state, the coil end portion is compression-molded by the third molding die. Thereby, the coil end part of desired shape can be shape | molded. At the time of compression molding in the axial direction, the second molding die is arranged so as to have an interval equivalent to the width of the final shape of the coil end portion. At that time, by making the width of the coil end portion narrower than the width of the final shape with the first molding die, the entire coil end portion can be securely sandwiched without hooking the motor coil with the second molding die. Thereby, the expansion in the radial direction is suppressed, and the entire coil end portion can be reliably compression-molded.

  The first molding die of the present invention includes a first outer diameter molding portion that presses the coil end portion from the outer diameter side toward the inner diameter side, and a first outer diameter pressing portion that presses the coil end portion from the inner diameter side toward the outer diameter side. A pair is formed by one inner diameter forming portion. And it is better if the first outer diameter molded portion has a smaller inner diameter as the distance from the stator core increases. Further, it is better that the first inner diameter molded portion has a larger outer diameter as the distance from the stator core increases. As a result, the width of the coil end portion compression-molded by the first outer diameter molding portion and the first inner diameter molding portion becomes narrower as the distance from the stator core increases. That is, the coil end portion is tapered. Therefore, problems such as hooking of the conductive wire when being sandwiched between the second molds are suppressed.

  Moreover, the 3rd shaping | molding die of this invention is the shape which the edge part protruded in the axial direction, and the curvature diameter by the side of the 2nd shaping | molding die of the front-end | tip part is 1/3 of the diameter of the conductive wire which comprises a motor coil. It is better to be within a range from 1 to 1/4. Furthermore, it is better that the radius of curvature on the side not on the second mold side is in the range of 1 to 2 times the diameter of the conductive wire constituting the motor coil. Accordingly, when the compression molding is performed with the third molding die, the conductive wire is suppressed from being sandwiched in the gap between the second molding die and the third molding die. For this reason, the rupture of the conductive wire film due to the stress concentration on the conductive wire is suppressed.

  According to the present invention, after the coil end portion expanded on the outer peripheral side is compression-molded in the radial direction, compression molding is performed in the axial direction. Thereby, the protrusion of the motor coil at the time of compression molding of the coil end portion can be reliably suppressed, and the coil end portion can be reliably made compact. Therefore, a motor coil molding apparatus and molding method that achieve both high space in the motor slot and compact coil end portions have been realized.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to a coil forming apparatus and a coil forming method for a coil for a vehicle driving motor mounted on a hybrid vehicle, an electric vehicle or the like.

  First, a method for inserting a motor coil will be described with reference to FIGS. The lower view of FIG. 1 is a view of the stator core 1 viewed from the axial direction, and the upper view of FIG. 1 is a cross-sectional view showing the AA cross section of the lower view of FIG. 2 to 6 have the same configuration.

  In this embodiment, motor coils formed by winding a predetermined copper wire in advance are prepared for three phases (hereinafter, each coil is referred to as “first coil”, “second coil”, and “third coil”). To do. Then, these motor coils are sequentially inserted into predetermined stator slots. The stator core 1 of the motor of this embodiment is provided with stator slots 21, 22, and 23 for inserting motor coils as shown in FIG. In each stator slot, the stator slot 21 corresponds to the first coil, the stator slot 22 corresponds to the second coil, and the stator slot 23 corresponds to the third coil.

  First, the stator core 1 is installed on a predetermined holding base of the coil insertion device. Then, as shown in FIG. 2, the first coil 31 is inserted into the stator slot 21 of the stator core 1. Immediately after the insertion of the first coil 31, as shown in the lower diagram of FIG. That is, the first coil 31 is in a state of closing the stator slot 22 and the stator slot 23.

  Next, as shown in FIG. 3, the coil end portion of the first coil 31 is pushed to the outer peripheral side of the stator core 1 in order to secure the insertion space for the second coil to be inserted next. That is, expansion molding of the coil end portion of the first coil 31 is performed. As a result, the stator slot 22 and the stator slot 23 are exposed as shown in the lower diagram of FIG. That is, an insertion space for the second coil is secured.

  Next, as shown in FIG. 4, the second coil 32 is inserted into the stator slot 22 of the stator core 1. Immediately after the insertion of the second coil 32, the second coil 32 straddles the first coil 31 as shown in the lower diagram of FIG. 4, and the stator slot 23 is covered by the second coil 32. That is, the second coil 32 closes the stator slot 23.

  Next, as shown in FIG. 5, the coil end portion of the second coil 32 is pushed to the outer peripheral side of the stator core 1 in order to secure the insertion space for the third coil to be inserted next. That is, expansion molding of the coil end portion of the second coil 32 is performed. As a result, the stator slot 23 is exposed as shown in the lower diagram of FIG. That is, an insertion space for the third coil is secured.

  Next, as shown in FIG. 6, the third coil 33 is inserted into the stator slot 23 of the stator core 1. After the third coil 33 is inserted, the third coil 33 straddles the first coil 31 and the second coil 32 as shown in the lower diagram of FIG. 6, and the corresponding motor coils are inserted into all the stator slots. It is in the state. This completes the insertion of the motor coil.

  Since the coil end portions of the first coil 31 and the second coil 32 are expanded after the motor coil is inserted, the coil end portions are expanded to the outer peripheral side in the radial direction. Therefore, in order to make the coil end portion compact, the expanded coil end portion is compression molded.

  Next, a device for forming the coil end portion of the motor coil will be described with reference to FIGS. As shown in FIG. 7, the molding apparatus of this embodiment has an outer diameter molding die 41 and an inner diameter molding die 42. The outer diameter mold 41 and the inner diameter mold 42 are a pair of molds and are provided to face each other in the radial direction. Further, the outer diameter molding die 41 is provided so as to be divided (divided type) as shown in the lower diagram of FIG. 7, and is movable in the radial direction (arrow direction in FIG. 7). When the coil end portion is formed, the coil end portion moves toward the inside in the radial direction, and the coil end portion can be pressed from the outer diameter side. On the other hand, the inner diameter forming die 42 is also provided so as to be splittable (split type) as shown in the lower diagram of FIG. 7, and is movable in the radial direction. When the coil end portion is molded, the coil end portion moves toward the outside in the radial direction, and the coil end portion can be pressed from the inner diameter side. That is, the molding apparatus of this embodiment can compress the coil end portion in the radial direction by pressing the coil end portion from the outer diameter side with the outer diameter molding die 41 and the inner diameter molding die 42 from the inner diameter side. .

  Further, the outer diameter mold 41 is provided with a predetermined angle (taper angle) so that the coil end portion after compression molding is closer to the stator core 1 as the width becomes larger as shown in the upper diagram of FIG. ing. Similarly, the inner diameter mold 42 is also provided with a predetermined angle. The taper angle of this embodiment is about 5 degrees for both the outer diameter mold 41 and the inner diameter mold 42.

  Furthermore, the molding apparatus of this embodiment has an axial direction molding die 43, an outer diameter molding die 44, and an inner diameter molding die 45 as shown in FIG. The axial molding die 43 has a ring shape along the final shape of the coil end portion, and is movable in the axial direction (the arrow direction in FIG. 8).

  Moreover, the axial direction shaping | molding die 43 is a shape which the edge part protruded in the axial direction (henceforth, the protruded part is called "edge part") (refer D of the upper figure of FIG. 8). When the coil end portion is formed, the clearance between the axial direction forming die 43 and the outer diameter forming die 44 is extremely small. Further, the tip of the edge portion of the axial molding die 43 is rounded as shown in FIG. Specifically, the curvature radius Ra of the edge portion in contact with the outer diameter mold 44 is in the range of 1/3 to 1/4 times the copper wire diameter. Moreover, the curvature diameter Rb of the site | part which contact | connects the corner | angular part of a coil end part among the axial direction shaping | molding dies 43 exists in the range of 1 to 2 times the copper wire diameter. The same applies to the edge portion in contact with the inner diameter mold 45.

  The outer diameter mold 44 and the inner diameter mold 45 are a pair of molds and are provided to face each other in the radial direction. Further, the outer diameter mold 44 has an inner diameter equal to the outer diameter of the final shape of the coil end portion. On the other hand, the outer diameter of the inner diameter mold 45 is equal to the inner diameter of the final shape of the coil end portion. The outer diameter mold 44 and the inner diameter mold 45 are provided such that the distance between them is equal to the width of the final shape of the coil end portion. Further, the outer diameter mold 44 and the inner diameter mold 45 are provided so as not to be divided (integrated type) and are movable in the axial direction. And the outer diameter shaping | molding die 44 and the inner diameter shaping | molding die 45 are arrange | positioned so that the coil end part installed in the predetermined holding stand may be inserted | pinched.

  The axial molding die 43 has a coil end portion sandwiched between the outer diameter molding die 44 and the inner diameter molding die 45 and is directed between the outer diameter molding die 44 and the inner diameter molding die 45 toward the stator core 1. Moving. Thereby, a coil end part can be pressed down from an axial direction. That is, the motor coil molding apparatus according to the present embodiment can compress the coil end portion in the axial direction by the axial molding die 43.

  Next, a method for forming a coil end portion using the forming apparatus of this embodiment will be described. In this embodiment, the coil end portions are compressed together in the radial direction and then compressed in the axial direction from that state.

  Specifically, first, the stator core 1 (see FIG. 6) around which the motor coil is wound is installed on a predetermined holding base. At this time, the outer diameter molding die 41 is in a separated state and is located on the outer side in the radial direction from the coil end portion (41 (a) in the lower diagram of FIG. 7). On the other hand, the inner diameter molding die 42 is in a joined state, and is located on the inner side in the radial direction from the coil end portion (42 (a) in the lower diagram of FIG. 7). 7 indicates the outer diameter of the coil end portion before compression molding.

  Next, the outer diameter mold 41 is moved radially inward (position 41 (b) in FIG. 7), and the inner diameter mold 42 is moved radially outward (position 42 (b) in FIG. 7). , Press contact the coil end. That is, as shown in FIG. 7, the outer diameter mold 41 presses the coil end portion in the radial direction from the outer diameter side, and the inner diameter mold 42 presses the coil end portion in the radial direction. As a result, the coil end portion is compression molded in the radial direction. That is, the expanded coil end portions are collected at a predetermined position in the radial direction.

  In addition, at the time of compression molding in the radial direction, the coil end portion is molded so as to be narrower than the final shape. That is, the outer shape mold 41 is formed so that the outer diameter of the coil end portion is smaller than the outer diameter of the final shape. Therefore, the outer diameter of the coil end portion after compression molding in the radial direction is smaller than the inner diameter of the outer diameter mold 44. Further, the inner diameter forming die 42 is formed so that the inner diameter of the coil end portion is larger than the inner diameter of the final shape. Therefore, the inner diameter of the coil end portion after the radial compression molding is larger than the outer diameter of the inner diameter mold 45. Along with this, the height of the coil end portion becomes higher than the height of the final shape of the coil end portion.

  In addition, since the outer diameter mold 41 and the inner diameter mold 42 are provided with a taper angle, the coil end portion after compression molding has a tapered shape. After the compression molding, the outer diameter molding die 41 is retracted radially outward, and the inner diameter molding die 42 is retracted radially inner.

  Next, the outer diameter mold 44 and the inner diameter mold 45 move to the stator core 1 side. At this time, since the width of the coil end portion is narrower than the width of the final shape, the entire coil end portion is accommodated between the outer diameter forming die 44 and the inner diameter forming die 45. As a result, as shown in FIG. 8, the entire coil end portion is sandwiched between the outer diameter mold 44 and the inner diameter mold 45. In addition, the axial direction shaping | molding die 43 is located in the axial direction outer side (43 (a) of the upper figure of FIG. 8) rather than a coil end part. In this state, the coil end portion is compression molded at high pressure by moving the axial molding die 43 to the axial stator core 1 side (position 43 (b) in FIG. 8). As a result, the coil end portion is compression molded to the final shape.

  As described in detail above, in the motor coil molding apparatus of this embodiment, first, the coil end portion is compressed in the radial direction by the outer diameter molding die 41 and the inner diameter molding die 42. This reduces the diameter of the coil end portion that is pushed outward when the coil is inserted. Thereafter, the coil end portion is sandwiched between the outer diameter forming die 44 and the inner diameter forming die 45, and in this state, the coil end portion is compressed in the axial direction by the axial direction forming die 43. That is, the coil end portions protruding in the radial direction by expansion molding are collected in a predetermined place, and then the entire coil end portion is covered and compression molding is performed again. As a result, it is possible to reliably suppress the extension of the expanded motor coil and to ensure the compactness of the entire motor. Therefore, a motor coil molding apparatus and molding method that achieve both high space in the motor slot and compact coil end portions have been realized.

  The outer diameter mold 41 and the inner diameter mold 42 are divided types. Therefore, these molds can be moved in the radial direction. Therefore, the degree of freedom of the outer diameter or inner diameter of the coil end portion after molding is high. That is, the outer diameter of the coil end portion can be made smaller than the outer diameter of the final shape, and the inner diameter of the coil end portion can be made larger than the inner diameter of the final shape. By making the width of the coil end portion smaller than the width of the final shape in this way, when the outer diameter forming die 44 and the inner diameter forming die 45 are arranged along the edge of the coil end portion, the forming die and the coil end portion are separated. Does not interfere. Therefore, there is no risk of the copper wire film being damaged due to the biting of the copper wire.

  The outer diameter molding die 44 and the inner diameter molding die 45 are integral types, unlike the outer diameter molding die 41 and the inner diameter molding die 42. Therefore, there is no risk that the copper wire will be caught in the crack or protrude from the crack. Furthermore, it has higher strength and rigidity than the split type. Therefore, it is suitable for high pressure molding. Therefore, it is effective for making the coil end portion compact.

  Further, the outer diameter molding die 41 and the inner diameter molding die 42 have a tapered contact surface with the coil end portion. For this reason, the coil end portion after compression molding has a tapered shape such that the width thereof becomes larger as it approaches the stator core 1. Therefore, the coil hooking can be suppressed during the axial compression molding.

  Further, as shown in FIG. 9, predetermined angles Ra and Rb are provided at the edge portion of the axial mold 43. Specifically, the angle Ra is set within a range of 1/3 to 1/4 times the copper wire diameter. In addition, the corner Rb is in the range of 1 to 2 times the copper wire diameter. This is because if the angle Ra is made larger than 1/3 times the copper wire diameter, the copper wire is sandwiched in the gap between the outer diameter forming die 44 and the axial forming die 43, breaking the copper wire coating. This is because there is a risk of scratching. On the other hand, if the angle Rb is made smaller than 1 times the diameter of the copper wire, the copper wire film may be damaged by the load concentration on the copper wire.

  Note that this embodiment is merely an example, and does not limit the present invention. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof. For example, in the embodiment, the present invention is applied to a motor in which a motor coil is inserted in three times, but the present invention is not limited to this. In other words, any motor can be used as long as the motor coil is inserted concentrically in a plurality of times.

  In the present embodiment, the coil end portion is formed for the coil for the vehicle drive motor, but the present invention is not limited to this. For example, you may apply this invention to the shaping | molding apparatus of the coil end part utilized for the motor for household appliances.

It is a figure which shows the stator core concerning embodiment. It is a figure which shows the state after insertion of the 1st coil concerning embodiment. It is a figure which shows the state after the expansion molding of the 1st coil concerning embodiment. It is a figure which shows the state after insertion of the 2nd coil concerning embodiment. It is a figure which shows the state after the expansion molding of the 2nd coil concerning embodiment. It is a figure which shows the state after insertion of the 3rd coil concerning embodiment. It is a figure which shows the state at the time of the inner-outer diameter shaping | molding of the coil end part concerning embodiment. It is a figure which shows the state at the time of the last shaping | molding of the coil end part concerning embodiment. It is an enlarged view of D part of the shaping | molding apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stator core 21 Stator slot 22 Stator slot 23 Stator slot 31 1st coil 32 2nd coil 33 3rd coil 41 (divided type) outer diameter shaping die 42 (divided type) inner diameter shaping die 43 Axial direction Mold 44 (integral type) outer diameter mold 45 (integral type) inner diameter mold

Claims (8)

In the method of forming the motor coil wound around the stator core slot,
The coil end part is compression molded so that the width of the coil end part becomes narrower than the width of the final shape of the coil end part by a pair of first molds capable of compressing and molding the coil end part of the motor coil in the radial direction. A first molding step,
After compression molding in the first molding step, a pair of second molding dies are arranged on the inner diameter side and outer diameter side in the radial direction of the coil end portion, and in that state, the coil end portion is compression molded in the axial direction. And a second molding step of compression-molding the coil end portion into a final shape by a third molding die capable of performing a motor coil molding method. The method for forming a motor coil according to claim 1,
In the first forming step, the coil end portion is formed such that the width of the coil end portion becomes narrower as the distance from the stator core is increased. In a motor coil forming apparatus for forming a coil end portion of a motor coil wound around a stator core slot,
A pair of first molding dies provided so as to be movable in the radial direction and compressing the coil end portion of the motor coil in the radial direction;
A pair of second molds arranged so as to be opposed to each other in the radial direction across the coil end portion;
An apparatus for forming a motor coil, comprising: a third mold that is provided so as to be movable in the axial direction and compresses and molds a coil end portion sandwiched between the second molds in the axial direction. In the motor coil shaping apparatus according to claim 3,
The first mold is
A first outer diameter molded portion that presses the coil end portion from the outer diameter side toward the inner diameter side;
A motor coil molding apparatus comprising a pair of coil end portions and a first inner diameter molding portion that presses the coil end portion from the inner diameter side toward the outer diameter side. In the motor coil forming apparatus according to claim 4,
The motor coil molding apparatus according to claim 1, wherein the first outer diameter molding portion has a smaller inner diameter as the distance from the stator core increases. In the motor coil molding device according to claim 4 or 5,
The apparatus for forming a motor coil according to claim 1, wherein the first inner diameter forming portion has a larger outer diameter as the distance from the stator core increases. In the motor coil shaping apparatus according to any one of claims 3 to 6,
The second mold is
A second outer diameter molded portion having an inner diameter that is the same as the outer diameter of the final shape of the coil end portion, and is disposed on the outer side in the radial direction of the coil end portion;
An apparatus for forming a motor coil, characterized in that the outer diameter is the same as the inner diameter of the final shape of the coil end portion, and a pair is formed by a second inner diameter forming portion disposed inside the coil end portion in the radial direction. In the motor coil shaping | molding apparatus as described in any one of Claims 3-7,
The said 3rd shaping | molding die is the shape which the edge part protruded in the axial direction, and the curvature diameter of the front-end | tip part exists in the range from 1/3 to 1/4 of the diameter of the electrically conductive wire which comprises a motor coil. An apparatus for forming a motor coil.

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