DE112021008516T5 - Method for producing a coil part and coil part - Google Patents

Abstract

The coil part (1) has a coil (10) and a core element (30) which includes a core part (31) arranged inside the coil. The method for producing this coil part comprises: a winding step, and an isostatic pressing step after the winding step. In the winding step, a winding wire (20) is wound in multiple layers on the core part (31) to form the coil (10) which has a crossing point (11) at which winding wire parts (21) adjacent in a stacking direction cross each other as viewed in the stacking direction, in a portion in the circumferential direction. In the isostatic pressing step, at least the crossing point (11) of the coil (10) in the state in which the core part (31) is arranged inside the coil (10) is pressed together with the core element (30) by isostatic pressing.

Description

TECHNICAL FIELD

The present invention relates to a method for producing a coil part with a coil and a core element which comprises a core part arranged inside the coil, and a coil part.

BACKGROUND TECHNOLOGY

Conventionally, coils formed by winding multi-layer wound winding wires are used for electrical equipment. For example, a coil part comprising this coil and a core member comprising a core part arranged inside the coil is included in electrical equipment. In the multi-layer winding of winding wires, a winding wire part of the upper layer is arranged so as to cross a winding wire part of the lower layer in a portion of the circumferential direction of the coil as viewed in the stacking direction. This portion is called a crossing point. In the portion of the coil that is not a crossing point, the winding wire part of the upper layer is arranged along the line longitudinal direction of the winding wire part of the lower layer. When the sectional shape of the winding wire is circular, in the portion of the coil that is not a crossing point, the winding wire part of the upper layer is arranged along a groove formed by two winding wire parts of the lower layer.

Patent Document 1 discloses a method for manufacturing a coil part used for a motor. In Patent Document 1, after a coil is formed by winding multi-layer wound winding wires having a circular sectional shape around a core part (a portion of a split stator core and a bobbin), a portion of the coil other than the coil end in the state where the core part is arranged inside the coil is pressed by a mold. The coil end is a portion in the circumferential direction of the coil that is not used in the slot of the stator. In motor coils, the coil end generally includes the crossing point. That is, it is estimated that the crossing point in Patent Document 1 is not pressed by the mold.

DETECTED TEXT

PATENT DOCUMENT

Patent Document 1: JP 2007-288983 A

SUMMARY OF THE INVENTION

TASK TO BE SOLVED BY THE INVENTION

When a coil is formed by winding a winding wire having a circular sectional shape, the winding wire part of the upper layer may be in linear contact with the winding wire part of the lower layer in the portion of the coil other than the crossing point along the line longitudinal direction. When a coil is formed by winding a winding wire having a rectangular sectional shape, the winding wire part of the upper layer may be in surface contact with the winding wire part of the lower layer in the portion of the coil other than the crossing point along the line longitudinal direction. On the other hand, when a coil is formed by winding a winding wire having a circular sectional shape, the winding wire part of the upper layer may be in only point contact with the winding wire part of the lower layer at the crossing point. For example, if, as in 6 shown, a coil 910 with different number of turns per layer is formed by winding a winding wire with a rectangular sectional shape, at the crossing point 911, the winding wire part 912 of the plurality of winding wire parts of one layer, which is located at the end in the axial direction CA of the coil, can only be in linear contact with the winding wire part 913 of the plurality of winding wire parts of the lower layer, which is located at the end in the axial direction CA of the coil. The dashed line in 6 indicates the line contact part. Thus, the contact area between the winding wire parts of adjacent layers at the crossing point is smaller than the contact area between the winding wire parts of adjacent layers at the non-crossing point.

When the outer peripheral surface of the coil is pressed by a mold, forces are applied to the outer peripheral surface of the coil in only one direction. Therefore, assuming that the crossing point is pressed by a mold, the force acts intensively on the small area where the winding wire parts are in contact with each other at the crossing point. As a result, the winding wire part subjected to an intensive force is easily deformed so that its sectional area is small. When the sectional area of the winding wire is locally small in this way, the electrical resistance of the coil increases. That is, assuming that at least the crossing point of the coil is pressed by the mold, the electrical resistance of the coil is likely to be increased. However, it is desirable that the coil has a low electrical resistance.

The purpose of the present invention is to provide a method for producing a coil part and a coil part which has the electrical can reduce the mechanical resistance of a coil while at least the crossing point of the coil is pressed.

MEANS TO SOLVE THE TASK

The inventors of the present application have conducted various tests to reduce the electrical resistance of the coil while pressing at least the crossing point of the coil. As a result, they found that when at least the crossing point of the coil is isostatically pressed together with the core member in the state where the core part is arranged inside the coil, the sectional area of the winding wire is not locally small and the sectional area of the winding wire at least at the crossing point can be larger than before pressing. As a result, the electrical resistance of the coil can be reduced. The present invention is based on this finding. In the present specification, the sectional area of the winding wire (or the winding wire part) means the area of the intersection of the winding wire (or the winding wire part) orthogonal to the line longitudinal direction.

• Ein Verfahren zur Herstellung eines Spulenteils mit einer Spule und einem Kernelement, das einen im Inneren der Spule angeordneten Kernteil umfasst, aufweisend: einen Wicklungsschritt, in dem ein Wickeldraht mehrlagig auf den Kernteil gewickelt wird, um die Spule zu bilden, die einen Kreuzungspunkt, an dem sich in einer Stapelrichtung benachbarte Wickeldrahtteile, in der Stapelrichtung gesehen, kreuzen, in einem Abschnitt in Umfangsrichtung aufweist, und einen Schritt zu einer isostatischen Pressung, in dem zumindest der Kreuzungspunkt der Spule nach dem Wicklungsschritt in dem Zustand, in dem der Kernteil im Inneren der Spule angeordnet ist, zusammen mit dem Kernelement durch eine isostatische Pressung gepresst wird.

A method for producing a coil part according to an embodiment of the present invention has the following configurations:

• A method for producing a coil part having a coil and a core element including a core part arranged inside the coil, comprising: a winding step in which a winding wire is wound in multiple layers on the core part to form the coil having a crossing point at which adjacent winding wire parts in a stacking direction cross each other as viewed in the stacking direction in a portion in the circumferential direction, and an isostatic pressing step in which at least the crossing point of the coil after the winding step is pressed together with the core element by isostatic pressing in the state in which the core part is arranged inside the coil.

After this formation, at least the crossing point of the coil is pressed together with the core member by the isostatic pressing. Here, the isostatic pressing molding is a molding method used for molding ceramics, etc., in which the pressure is applied isostatically, so that a molded body with homogeneous density and low directivity can be obtained. When a coil is subjected to isostatic pressing, the internal space (gap between the winding wire parts, gap between the winding wire part and the core member) is reduced, and the winding wire moves in a direction in which the elements (winding wire part or the core member) approach each other because the coil and the core member move in a direction in which the internal density of the coil and the core member approaches homogeneity. This causes the points that are not in contact with each other to come into contact with the adjacent elements (winding wire part or the core member). It can therefore be suppressed that the force acts intensively on the small area in which the winding wire parts are in contact with each other at the crossing point. In contrast to coils in which the crossing point is pressed by a mold, the sectional area of the winding wire does not become locally small at the crossing point.

Since at least the crossing point of the coil is pressed together with the core member by isostatic pressing in the state where the core part is arranged inside the coil, the winding wire part of the lowermost layer moves toward the core part at least at the crossing point, and the winding wire part of the uppermost layer at the crossing point also moves toward the core part. At this time, the winding wire part is subjected to a compressive force in the line longitudinal direction at least at the crossing point. The sectional area of the winding wire can therefore be larger than before pressing at least at the crossing point. In contrast, when at least the crossing point of the coil is pressed by isostatic pressing in the state where nothing is arranged inside the coil, the winding wire part of the uppermost layer moves toward the lower layer at least at the crossing point and is subjected to a compressive force in the line longitudinal direction of the winding wire part. However, if no elements are arranged inside the coil, a movement takes place in the direction of a homogeneous internal density, so that the winding wire part of the lowermost layer moves in the direction of the upper layer at least at the crossing point and is subjected to a tensile force in the longitudinal direction of the winding wire part. As a result, at least the sectional area of the winding wire part of the lowermost layer is reduced at least at the crossing point. A coil in which at least the crossing point is pressed by isostatic pressing in the state in which the core part is arranged inside the coil can therefore have a larger sectional area of the winding wire at least at the crossing point compared to a coil in which at least the crossing point is pressed by isostatic pressing in the state in which nothing is arranged inside the coil.

Thus, the sectional area of the winding wire is not locally small, although at least the crossing point of the coil is pressed, and moreover, the sectional area of the winding wire can be at least at the crossing point than before pressing. Therefore, the electrical resistance of the coil can be reduced.

• Der Kernteil ist aus einem kompressiblen Material gebildet.

The method for producing a coil part according to an embodiment of the present invention may also have the following configuration:

• The core part is made of a compressible material.

When the core part is formed of a non-compressible material, the core part is deformed in a direction orthogonal to the axial direction of the coil by the application of a force in the axial direction of the coil in the isostatic pressing step. As a result, the winding wire part of the lowermost layer of the coil moves toward the upper layer. In contrast, since the core part is formed of a compressible material, the winding wire part of the lowermost layer of the coil does not move toward the upper layer in the isostatic pressing step. Therefore, the sectional area of the winding wire can be larger than before pressing, and the electrical resistance of the coil can be reduced.

• Im Schritt zur isostatischen Pressung wird der gesamte Umfang der Spule in dem Zustand, in dem der Kernteil im Inneren der Spule angeordnet ist, zusammen mit dem Kernelement durch isostatische Pressung gepresst.

The method for producing a coil part according to an embodiment of the present invention may also have the following configuration:

• In the isostatic pressing step, the entire circumference of the coil in the state where the core part is arranged inside the coil is pressed together with the core element by isostatic pressing.

According to this constitution, the entire circumference of the coil having crossing points in the state where the core part is arranged inside the coil is pressed together with the core member by isostatic pressing. Therefore, compared with the case where only a portion of the coil having crossing points in the circumferential direction in the state where the core part is arranged inside the coil is pressed together with the core member by isostatic pressing, the number of places where the sectional area of the winding wire is large can be increased. In addition, the sectional area of the winding wire can be made even larger if necessary. Therefore, the electrical resistance of the coil can be further reduced.

• Der Kernteil umfasst mindestens einen Abschnitt jedes von mehreren Teilen, die in einer Richtung, die die axiale Richtung der Spule kreuzt, nebeneinander angeordnet und mechanisch verbunden sind.

The method for producing a coil part according to an embodiment of the present invention may also have the following configuration:

• The core part includes at least a portion of each of a plurality of parts arranged side by side in a direction crossing the axial direction of the coil and mechanically connected.

According to this configuration, immediately before the isostatic pressing step, a small gap in the direction crossing the axial direction of the coil can be generated between a plurality of parts which are juxtaposed in the direction crossing the axial direction of the coil and mechanically connected to each other. In this case, the gap in the direction crossing the axial direction of the coil between a plurality of parts in the state where the core part is arranged inside the coil can be reduced by isostatically pressing the entire circumference of the coil together with the core member in the isostatic pressing step. As a result, the length of the core part in the direction crossing the axial direction of the coil can be shortened. The circumferential length of the inner and outer portions in the circumferential direction of the coil can therefore be further shortened. As a result, the sectional area of the winding wire can be further increased and the electrical resistance of the coil can be reduced.

• Der Spulenteil weist mehrere Spulen auf, das Kernelement weist mehrere Kernteile auf, im Wicklungsschritt werden mehrere Wickeldrähte jeweils mehrlagig auf die mehreren Kernteile gewickelt, um die mehreren Spulen zu bilden, die den Kreuzungspunkt jeweils in einem Abschnitt in Umfangsrichtung aufweisen, und im Schritt zu einer isostatischen Pressung wird zumindest der Kreuzungspunkt der mehreren Spulen in dem Zustand, in dem die mehreren Kernteile im Inneren der mehreren Spulen angeordnet sind, zusammen mit dem Kernelement durch isostatische Pressung gepresst.

The method for producing a coil part according to an embodiment of the present invention may also have the following configuration:

• The coil part has a plurality of coils, the core element has a plurality of core parts, in the winding step, a plurality of winding wires are wound on the plurality of core parts in multiple layers to form the plurality of coils each having the crossing point in a portion in the circumferential direction, and in the isostatic pressing step, at least the crossing point of the plurality of coils in the state where the plurality of core parts are arranged inside the plurality of coils is pressed together with the core element by isostatic pressing.

After this formation, although at least the crossing points of the multiple coils are simultaneously pressed, the sectional area of the winding wire is not locally small, and the sectional area of the winding wire in the multiple coils can be larger than before pressing. Therefore, the electrical resistance of the multiple coils can be reduced.

• Im Wicklungsschritt wird ein Wickeldraht mit einer kreisförmigen Schnittform gewickelt, um eine Spule zu bilden.

The method for producing a coil part according to an embodiment of the present invention may also have the following configuration:

• In the winding step, a winding wire with a circular sectional shape is wound to form a coil.

When a coil is formed by winding a winding wire having a circular sectional shape, the volume of the gap between the winding wire parts at the crossing point tends to increase compared with the case where a coil is formed by winding a winding wire having a rectangular sectional shape. Therefore, when at least the crossing point of the coil is pressed together with the core member by isostatic pressing in the state where the core part is arranged inside the coil, the moving distance of the winding wire part of the uppermost layer of the coil toward the core part tends to be longer at least at the crossing point than in the case of the winding wire having a rectangular sectional shape. That is, the winding wire parts can be subjected to a larger pressing force in the line longitudinal direction at least at the crossing point than in the case of the winding wire having a rectangular sectional shape. Therefore, the sectional area of the winding wire at least at the crossing point can be larger than when a coil is formed by winding a winding wire having a rectangular sectional shape in the winding step.

• Die isostatische Pressung, die im Schritt zur isostatischen Pressung durchgeführt wird, ist eine isostatische Pressung unter Verwendung mindestens eines von einem flüssigen Druckmedium, einem gasförmigen Druckmedium und einem elastischen festen Druckmedium.

The method for producing a coil part according to an embodiment of the present invention may also have the following configuration:

• The isostatic pressing performed in the isostatic pressing step is isostatic pressing using at least one of a liquid pressure medium, a gaseous pressure medium, and an elastic solid pressure medium.

• Es liegt ein Spulenteil mit einer Spule und einem Kernelement vor, das einen Kernteil umfasst, der im Inneren der Spule angeordnet ist. Die Spule ist mit einem Wickeldraht gebildet, der mehrlagig auf den Kernteil gewickelt ist, wobei die Schnittform des Endes des Wickeldrahts, das ein nicht auf den Kernteil gewickelter Auszugsteil ist, kreisförmig ist, die Spule in einem Abschnitt in Umfangsrichtung einen Kreuzungspunkt aufweist, an dem sich in der Stapelrichtung benachbarte Wickeldrahtteile, in der Stapelrichtung gesehen, kreuzen, und die Spule in einem anderen Abschnitt in der Umfangsrichtung einen parallelen Bereich aufweist, in dem der Wickeldrahtteil der oberen Lage entlang der von dem Wickeldrahtteil der unteren Lage gebildeten Nute angeordnet ist. Der Kernteil ist nicht einteilig mit der Spule geformt. Wenn die Außenumfangsfläche des Kernteils zwei parallele Ebenen aufweist, stehen die beiden parallelen Ebenen in Kontakt mit dem Wickeldraht, und wenn die Außenumfangsfläche des Kernteils nicht zwei parallele Ebenen aufweist, sondern zwei nicht parallele Ebenen aufweist, stehen eine der beiden Ebenen der Außenumfangsfläche des Kernteils und eine Ecke, die kein Ende dieser Ebene ist, in Kontakt mit dem Wickeldraht, oder eine gekrümmte Oberfläche der Außenumfangsfläche des Kernteils und eine Ecke, die kein Ende dieser Oberfläche ist, in Kontakt mit dem Wickeldraht stehen, und die Schnittform des Kernteils kreisförmig oder elliptisch ist, stehen drei oder mehr Punkte einschließlich der beiden Enden in Umfangsrichtung im Bereich von 180° oder mehr auf der Außenumfangsfläche des Kernteils mit dem Wickeldraht in Kontakt. Wenn die Außenumfangsfläche des Kernteils eine Ebene aufweist, ist der Wickeldraht derart gebogen, dass mehrere in der Stapelrichtung konkave Vertiefungen in dem Abschnitt der Außenumfangsfläche der Spule, der die eine Ebene des Kernteils bedeckt, in der Umfangsrichtung nebeneinander vorliegen, und wenn die Schnittform des Kernteils kreisförmig oder elliptisch ist, ist der Wickeldraht in einem Abschnitt der Spule, der weder ein Kreuzungspunkt, noch eine Grenze zwischen dem Kreuzungspunkt und dem parallelen Bereich ist, in axialer Richtung der Spule gebogen. In jedem Schnitt, der orthogonal zur Umfangsrichtung des Spulenteils steht und durch den Kreuzungspunkt geht, enthalten die mehreren Wickeldrahtteile abgesehen von den mehreren Wickeldrahtteilen, die am Ende in axialer Richtung der Spule positioniert sind, keinen Wickeldrahtteil, der mit benachbarten Wickeldrahtteilen in Kontakt stehende Vertiefungen an zwei gegenüberliegenden Positionen am äußeren Rand aufweist.

The coil part according to an embodiment of the present invention has the following configuration:

• There is a coil part having a coil and a core element comprising a core part arranged inside the coil. The coil is formed with a winding wire wound in multiple layers on the core part, the sectional shape of the end of the winding wire, which is an extension part not wound on the core part, being circular, the coil having a crossing point in one section in the circumferential direction at which adjacent winding wire parts in the stacking direction cross each other as seen in the stacking direction, and the coil having a parallel region in another section in the circumferential direction in which the winding wire part of the upper layer is arranged along the groove formed by the winding wire part of the lower layer. The core part is not formed integrally with the coil. When the outer peripheral surface of the core part has two parallel planes, the two parallel planes are in contact with the winding wire, and when the outer peripheral surface of the core part does not have two parallel planes but has two non-parallel planes, one of the two planes of the outer peripheral surface of the core part and a corner that is not an end of this plane are in contact with the winding wire, or a curved surface of the outer peripheral surface of the core part and a corner that is not an end of this surface are in contact with the winding wire, and the sectional shape of the core part is circular or elliptical, three or more points including the two ends in the circumferential direction in the range of 180° or more on the outer peripheral surface of the core part are in contact with the winding wire. When the outer peripheral surface of the core part has a plane, the winding wire is bent such that a plurality of concave depressions in the stacking direction are adjacent to each other in the circumferential direction in the portion of the outer peripheral surface of the coil covering the one plane of the core part, and when the sectional shape of the core part is circular or elliptical, the winding wire is bent in the axial direction of the coil in a portion of the coil that is neither an intersection point nor a boundary between the intersection point and the parallel region. In each section that is orthogonal to the circumferential direction of the coil part and passes through the intersection point, the plurality of winding wire parts, other than the plurality of winding wire parts positioned at the end in the axial direction of the coil, do not include a winding wire part that has depressions in contact with adjacent winding wire parts at two opposite positions on the outer edge.

According to this design, the sectional shape of the end of the winding wire, which is an extension part not wound on the core part, is circular. That is, the sectional shape of the winding wire when the winding wire is wound on the core part is circular.

Further, according to this constitution, the core part is not formed integrally with the coil. Therefore, the core part is not a core part formed after the entire circumference of the coil is pressed by isostatic pressing in the state where nothing is arranged inside the coil.

If the outer peripheral surface of the core part has two parallel planes, the two parallel planes are in contact with the winding wire. When the outer peripheral surface of the core part does not have two parallel planes but has two non-parallel planes, one of the two planes of the outer peripheral surface of the core part and a corner other than an end of this plane are in contact with the winding wire, or a curved surface of the outer peripheral surface of the core part and a corner other than an end of this surface are in contact with the winding wire. When the sectional shape of the core part is circular or elliptical, three or more points including the two ends in the circumferential direction in the range of 180° or more on the outer peripheral surface of the core part are in contact with the winding wire. Therefore, the core part is not a core part that is arranged inside the coil after the entire circumference of the coil is pressed by isostatic pressing in the state where nothing is arranged inside the coil.

According to this constitution, further, when the outer peripheral surface of the core part has a plane, the winding wire is bent such that a plurality of concave depressions in the stacking direction are adjacent to each other in the circumferential direction in the portion of the outer peripheral surface of the coil covering this plane. When the sectional shape of the core part is circular or elliptical, the winding wire is bent in the axial direction of the coil in a portion of the coil which is neither an intersection point nor a boundary between the intersection point and the parallel region. Thus, the coil is not a coil which is not pressed at all. Further, the coil is not a coil in which only a portion of the coil in the circumferential direction other than the intersection point is pressed by the mold.

In each section orthogonal to the circumferential direction of the coil part and passing through the crossing point, the plurality of winding wire parts, other than the plurality of winding wire parts positioned at the end in the axial direction of the coil, do not include a winding wire part having recesses in contact with adjacent winding wire parts at two opposite positions on the outer edge. Therefore, the coil is not a coil whose crossing point is pressed by a mold. When the crossing point is pressed by a mold, the sectional shape of the winding wire part at a position at the crossing point other than the axial end of the coil is easily deformed to have recesses at two opposite positions on the outer edge because the force is intensely applied to the position of the winding wire part at the crossing point which is in point contact. The sectional area of the winding wire part thus deformed is smaller than the sectional area of the other winding wire parts.

Accordingly, the coil part having the above configuration is a coil part obtained by pressing the entire circumference of the coil with the crossing points in the state where the core part is arranged inside the coil together with the core member by isostatic pressing. Here, isostatic press molding is a molding method used for molding ceramics, etc., in which pressure is applied isostatically so that a molded body having homogeneous density and low directionality can be obtained. When a coil is subjected to isostatic pressing, since the coil and the core member move in a direction in which the internal density of the coil and the core member approaches homogeneity, the internal space (gap between the winding wire parts, gap between the winding wire part and the core member) is reduced, and the winding wire moves in a direction in which the members (winding wire part or the core member) approach each other. This causes the points that are not in contact with each other to come into contact with the adjacent elements (winding wire part or core element). It can therefore be suppressed that the force is intensively applied to the point of the winding wire part at the crossing point that is in point contact. Therefore, unlike coils in which the crossing point is pressed by a mold, the sectional area of the winding wire at the crossing point does not become locally small.

Since the entire circumference of the coil is pressed together with the core element by isostatic pressing in the state where the core part is arranged inside the coil, the winding wire part of the lowermost layer moves toward the core part, and the winding wire part of the uppermost layer also moves toward the core part. At this time, the winding wire is subjected to a compressive force in the line longitudinal direction. The sectional area of the winding wire can therefore be larger than before pressing. In contrast, when the entire circumference of the coil is pressed by isostatic pressing in the state where nothing is arranged inside the coil, the winding wire part of the uppermost layer moves toward the lower layer and is subjected to a compressive force in the line longitudinal direction of the winding wire part. However, when no elements are arranged inside the coil, a movement toward a homogeneous internal density takes place, so that the winding wire part of the lowermost layer moves toward the upper layer and is subjected to a tensile force in the line longitudinal direction of the winding wire part. This reduces at least the sectional area of the winding wire part of the lowest layer. A coil in which the entire circumference is isostatically pressed in the state in which the core part is arranged inside the coil. can therefore have a larger sectional area of the winding wire compared to a coil in which the entire circumference is pressed by isostatic pressing in the state where nothing is arranged inside the coil.

Thus, the sectional area of the winding wire is not locally small even though the entire circumference of the coil is pressed with the intersection point, and moreover, the sectional area of the winding wire can be larger than before pressing. Therefore, the electrical resistance of the coil can be reduced.

• In jedem Schnitt, der orthogonal zur Umfangsrichtung des Spulenteils steht und durch den Kreuzungspunkt geht, steht jeder der mehreren Wickeldrahtteile abgesehen von den mehreren Wickeldrahtteilen, die am Ende in axialer Richtung der Spule positioniert sind, in Kontakt mit Wickeldrahtteilen, die in axialer Richtung der Spule benachbart und nicht am Ende in axialer Richtung der Spule positioniert sind.

The coil part according to an embodiment of the present invention can also have the following design:

• In each section orthogonal to the circumferential direction of the coil part and passing through the crossing point, each of the plurality of winding wire parts, except for the plurality of winding wire parts positioned at the end in the axial direction of the coil, is in contact with winding wire parts adjacent in the axial direction of the coil and not positioned at the end in the axial direction of the coil.

At the crossing point, the winding wire parts of the adjacent layers cross each other, and the position of the winding wires is easily disturbed. Therefore, when the crossing point is pressed by a mold, the distance between the adjacent winding wire parts in the axial direction of the coil at the crossing point may become larger. On the other hand, when the entire circumference of the coil is pressed by isostatic pressing in the state where the core part is arranged inside the coil, each of the plurality of winding wire parts, except for the plurality of winding wire parts positioned at the end in the axial direction of the coil, may be in contact with the winding wire parts adjacent in the axial direction of the coil and not positioned at the end in the axial direction of the coil in each cut through the crossing point. Since the disturbance of the position of the winding wire is suppressed in this way, the deformation of the winding wire during pressing, which causes the sectional area of the winding wire at the crossing point to be locally small, rarely occurs. Therefore, the electrical resistance of the coil can be reduced.

Depending on the application of the coil, the number of turns per layer may vary, so that winding wire parts that are not positioned at the end in the axial direction of the coil may not be in contact with the winding wire parts adjacent in the axial direction of the coil.

In the method for manufacturing the coil member and the coil member of the present invention, the core member is a member disposed inside the coil. The core member not including a portion not disposed inside the coil may be an independent member. At least a portion of the core member may be inseparably integrated with a portion of the core member.

In the method for manufacturing the coil part and the coil part of the present invention, the application of the coil part is not particularly limited as long as it is an electrical device. The coil part can be used in electrical devices that utilize the electromagnetic induction of the coil. For example, the coil part can be used in armatures of rotating electrical machines, field magnets of rotating electrical machines, inductors, and transformers. A rotating electrical machine is an electrical device that functions as at least one of a motor and a generator. When the coil part is used in the armature of a rotating electrical machine, the coil part can be used in the rotor or the stator. When the coil part is used in the rotor of a rotating electrical machine, the core element of the coil part can include the rotor core, include only a portion of the rotor core, or need not include at least a portion of the rotor core. When the coil part is used in a stator of a rotating electrical machine, the core element of the coil part may include the stator core, may include only a portion of the stator core, or may not include at least a portion of the stator core. When the coil part is used in an armature of a rotating electrical machine, the coil part may be used in, for example, an axial-gap rotating electrical machine stator, an inner-rotor radial-gap rotating electrical machine stator, or an outer-rotor radial-gap rotating electrical machine stator. In the following explanation, the stator of a rotating electrical machine means a stator that constitutes the armature of a rotating electrical machine. When the coil part is used in an axial-gap rotating electrical machine stator, the sectional shape of the core element is, for example, a rectangle, an isosceles triangle, an isosceles trapezoid, or a fan shape. In the present specification, the sectional shape of the core part means the shape of the section of the core part orthogonal to the axial direction of the coil. When the coil part is used in a stator of a rotating electric machine with a radial gap, the sectional shape of the core part is, for example, a rectangle. When the coil part is used in a transformer, the sectional shape of the core member is, for example, a Rectangle, a circle, rounded rectangle or oval (including elliptical shape). In the following explanation, when simply referring to a rotating electrical machine, it means a rotating electrical machine with an axial or radial gap. When the coil part is used in the stator of a rotating electrical machine, the form of the winding wire of the coil of the rotating electrical machine can be either a concentrated winding or a distributed winding.

In the method for manufacturing the coil part and the coil part of the present invention, the coil part may include a core element having a plurality of core parts and a plurality of coils, or may include a core element having a single core part and a single coil. When the coil part is used in a stator of a rotating electrical machine and the stator has a one-piece or split stator core, the core element may include, for example, a stator core and a plurality of insulating coil bodies or a plurality of insulating papers. In this case, the coil part includes a core element having a plurality of core parts and a plurality of coils. The insulating coil body or the insulating paper is arranged between the stator core and the coil. When the coil part is used in a stator of a rotating electrical machine and the stator has a one-piece or split stator core, the core element may include, for example, only an insulating coil body. In this case, the coil part includes a core element having a single core part and a single coil. When the coil part is used in a stator of a rotating machine and the stator has a split stator core, the core member may include a portion of the split stator core and a single insulating coil body or a single insulating paper. In this case, the coil part includes a core member having a single core portion and a single coil. When the coil part is used in a stator of a rotating electrical machine and the winding type of the coil of the rotating electrical machine is a distributed winding, the coil part includes a core member having multiple core portions and multiple coils. In this case, a core portion is composed of two portions circumferentially separated from each other around the central axis of the rotating machine.

In the method of manufacturing the coil part and the coil part of the present invention, the core member may include a first part having the core part and a second part separable from the first part. The method of manufacturing the coil part of the present invention may include a winding step of winding a winding wire around the core part of the first part to form a coil, and an assembly step of coupling the first part to the second part to form the core member after the winding step and before the isostatic pressing step. For example, when the coil part is used in a stator of a rotating electrical machine, the first part may be an insulating bobbin and the second part may be a stator core.

In the method for manufacturing the coil part and the coil part of the present invention, the core member may have a portion facing one end in the axial direction of the coil at least in a portion of the circumferential direction of the coil in the axial direction of the coil. In the method for manufacturing the coil part and the coil part of the present invention, the core member may have two portions facing the two ends in the axial direction of the coil at least in a portion of the circumferential direction of the coil in the axial direction of the coil, respectively. In the method for manufacturing the coil part and the coil part of the present invention, the core member may have a portion facing one end of the coil in the axial direction of the coil over the entire circumference in the axial direction of the coil. In the method for manufacturing the coil part and the coil part of the present invention, the core member may have two portions facing the two ends in the axial direction of the coil over the entire circumference in the axial direction of the coil.

In the method for manufacturing the coil part of the present invention, the pressing of at least the crossing point of the coil together with the core member by isostatic pressing includes the case where the entire circumference of the coil is pressed together with the core member by isostatic pressing and the case where a portion in the circumferential direction including the crossing point of the coil together with the core member is pressed by isostatic pressing. In the case where a portion in the circumferential direction including the crossing point of the coil together with the core member is pressed by isostatic pressing, for example, a portion in the circumferential direction of the coil that is not pressed may be pressed by isostatic pressing while covered with a cover. The cover is made of, for example, a rigid, compressible material. The cover is, for example, fixed to the core member. The cover is not pressed against the coil in the isostatic pressing step. Specifically, the isostatic pressing is performed, for example, with such a pressure that the cover is not deformed. Alternatively, the cover is designed in such a way that it does not touch the coil, even if it is slightly deformed by the application of isostatic pressure force. In any case, the Cover is provided such that in the isostatic pressing step, a pressure medium and/or a flexible bag, which will be described later, is not deformed and penetrates between the cover and the coil.

In the method for manufacturing the coil member of the present invention, the isostatic pressing means using at least one of a liquid pressure medium, a gaseous pressure medium, and an elastic solid pressure medium as a pressure medium that imparts isostatic pressure to the coil. Isostatic pressing using at least one of a liquid pressure medium, a gaseous pressure medium, and an elastic solid pressure medium may be isostatic pressing with a liquid pressure medium and a gaseous pressure medium, isostatic pressing with a liquid pressure medium and an elastic solid pressure medium, isostatic pressing with a gaseous pressure medium and an elastic solid pressure medium, and isostatic pressing with a gaseous pressure medium, a liquid pressure medium, and an elastic solid pressure medium. The liquid pressure medium may be a liquid pressure medium of a liquid at normal temperature or a liquid pressure medium of a liquid at a temperature higher than normal temperature. The gaseous pressure medium may be a pressure medium of a gas at normal temperature or a pressure medium of a gas at a temperature higher than normal temperature. The elastic solid pressure medium is preferably a pressure medium made of a rubber-elastic solid. The pressure medium of an elastic solid may be made of rubber or an elastomer other than rubber. When a liquid or gaseous pressure medium is used, the coil and the core element are enclosed in a flexible bag in the isostatic pressing step. The flexible bag may or may not be an elastic solid pressure medium. For example, if the flexible bag is very thin, the flexible bag is not an elastic solid pressure medium. There is preferably a vacuum inside the flexible bag, but air may also remain. The outer peripheral surface of the coil is not in contact with the liquid pressure medium. The outer peripheral surface of the coil is not in contact with the gaseous pressure medium. The outer peripheral surface of the coil is in contact with the elastic solid pressure medium or the flexible bag. Isostatic pressing with at least one liquid pressure medium as the pressure medium is e.g. B. cold isostatic wet pressing (WET CIP: Wet type Cold Isostatic Pressing or Wet-Bag Cold Isostatic Pressing), cold isostatic dry pressing (DRY CIP: Dry type Cold Isostatic Pressing or Dry-Bag Cold Isostatic Pressing) or isostatic pressing with a liquid pressure medium at a temperature above normal temperature. Isostatic pressing with at least one gaseous pressure medium as the pressure medium corresponds, for example, to hot isostatic pressing (HIP: Hot Isostatic Pressing) or isostatic pressing with a gaseous pressure medium at normal temperature. Isostatic pressing with at least one elastic, solid pressure medium as the pressure medium is, for example, cold isostatic dry pressing (DRY CIP: Dry type Cold Isostatic Pressing or Dry-Bag Cold Isostatic Pressing) or rubber isostatic pressing (RIP: Rubber Isostatic Pressing). Wet cold isostatic pressing (WET CIP) and dry cold isostatic pressing (DRY CIP) use a liquid pressure medium at normal temperature. Hot isostatic pressing (HIP) uses a hot gaseous pressure medium. Hot isostatic pressing is a pressing process in which pressing and heat treatment can be carried out simultaneously. The temperature of the gaseous pressure medium in hot isostatic pressing is not particularly limited as long as it is higher than normal temperature.

In the method for manufacturing the coil part and the coil part of the present invention, the winding wire includes a conductor and an insulating film covering the outer peripheral surface of the conductor. The winding wire may be a single wire or a stranded wire. In the method for manufacturing the coil part and the coil part of the present invention, the winding wire part means a portion of the winding wire. In the method for manufacturing the coil part and the coil part of the present invention, the stacking direction is a direction in which a plurality of layers formed by the winding wire are stacked. In the present specification, the upper layer and the lower layer refer to any two layers among a plurality of layers that are adjacent in the stacking direction. The lower layer is the layer that is closer to the core part than the upper layer. In the method for manufacturing the coil part and the coil part of the present invention, a crossing point is not a term that merely refers to a location where two winding wire parts adjacent in the stacking direction cross each other as viewed in the stacking direction. The crossing point comprises at least one winding wire part of the adjacent layer which crosses several winding wire parts of a layer, viewed in the stacking direction. At the crossing point, at least one winding wire part of each layer can cross a winding wire part of an adjacent layer, viewed in the stacking direction. The method for producing the coil part and the coil part of the present invention have a crossing point in a portion of the circumferential direction. At a portion of the In the circumferential direction which is not a crossing point of the coil, the winding wire part of the upper layer is arranged along the line longitudinal direction of the winding wire part of the lower layer. In the method of manufacturing the coil part and the coil part of the present invention, the coil may have two crossing points or a single crossing point. In the coil part of the present invention, a parallel region includes a winding wire part in an upper layer arranged at least along a groove formed by two winding wire parts of one layer. In the parallel region, at least one winding wire part of each layer except for the lowermost layer may be arranged along the groove formed by two winding wire parts of the adjacent layer. In the coil part of the present invention, the winding method of the coil is orthocyclic winding. In the method of manufacturing the coil of the coil part of the present invention, the winding method of the coil may be orthocyclic winding. In the method for manufacturing the coil part of the present invention, the winding method of the coil is neither wild winding nor helical winding.

In the method for manufacturing the coil part of the present invention, the core part formed of compressible material means a core part formed of compressible material having a Poisson's ratio smaller than 0.49. In the coil part of the present invention, the core part may be formed of a compressible material having a Poisson's ratio smaller than 0.49.

In the method for manufacturing the coil part of the present invention, a plurality of mechanically connected parts may be, for example, a plurality of parts connected by means of fasteners such as screws or bolts, or a plurality of parts connected by caulking. The plurality of parts connected by caulking may be, for example, a plurality of electromagnetic steel plates. In the method for manufacturing the coil part of the present invention, when the core part includes a plurality of parts arranged side by side in a direction crossing the axial direction of the coil and mechanically connected, a plurality of parts may be aligned in a direction orthogonal to the axial direction of the coil.

In the method for manufacturing the coil part of the present invention, the winding wire having a circular sectional shape means a winding wire whose sectional shape orthogonal to the line length direction of the winding wire is circular. The sectional shape of the winding wire in the present specification means the shape of a section orthogonal to the line length direction of the winding wire. In the present specification, the sectional shape of the winding wire part means the shape of a section orthogonal to the line length direction of the winding wire part.

In the coil part of the present invention, the extension part having a circular sectional shape means an extension part whose sectional shape is circular orthogonal to the line longitudinal direction of the extension part. In the coil part of the present invention, the extension part, which is the end of the winding wire, is not connected to the portion of the winding wire other than the extension part by welding, etc., but has the same structure as the portion of the winding wire other than the extension part.

In the coil part of the present invention, the core part which is not molded integrally with the coil means a core part which is not a core part which is press-molded by filling the mold in which the coil is arranged with an empty core with magnetic material. Whether the core part is molded integrally with the coil can be determined from the shape of the outer peripheral surface of the core part. When the core part is molded integrally with the coil, the molding material made of a mixture of, for example, magnetic powder and resin penetrates into the gap between the winding wire parts of the lowermost layer and hardens in that state. Therefore, when the core part is molded integrally with the coil, a projection is formed on the outer peripheral surface of the core part and is arranged in the gap between adjacent winding wire parts.

In the coil part of the present invention, the case where the outer peripheral surface of the core part has two parallel planes is, for example, when the shape of the section of the core part orthogonal to the axial direction of the coil is a rectangle, a rounded rectangle, or a trapezoid. In the coil part of the present invention, the case where the outer peripheral surface of the core part has not two parallel planes but two non-parallel planes is, for example, when the shape of the section of the core part orthogonal to the axial direction of the coil is a triangle or a fan shape. In the coil part of the present invention, the core part having a circular or elliptical sectional shape means a core part whose sectional shape orthogonal to the axial direction of the coil is circular or elliptical.

In the coil member of the present invention, when the outer peripheral surface of the core member has not two parallel planes but two non-parallel planes, the outer peripheral surface of the core member may have a curved surface on or need not have them. When the outer peripheral surface of the core part has not two parallel planes but two non-parallel planes and a curved surface, one of the two non-parallel planes and a corner other than an end of this plane may be in contact with the winding wire, and this curved surface and a corner other than an end of this plane may be in contact with the winding wire.

In the coil part of the present invention, when three or more points including both ends in the circumferential direction within a range of 180° or more on the outer peripheral surface of the core part are in contact with the winding wire, this does not include the cases where these three or more points fall within a range of less than 180° on the outer peripheral surface of the core part. In the coil part of the present invention, the three or more points on the outer peripheral surface of the core part that are in contact with the winding wire means that three or more points on the outer peripheral surface of the core part that are separated from each other in the circumferential direction are in contact with the winding wire. The contact may be a point contact, a line contact or a surface contact.

The coil part of the present invention is characterized in that, when the outer peripheral surface of the core part has a plane, the winding wire is bent such that, in the portion of the outer peripheral surface of the coil covering this one plane, a plurality of concave depressions in the stacking direction are adjacent to each other in the circumferential direction. In this case, the winding wire is bent in the stacking direction in the portion of the outer peripheral surface of the coil covering the one plane of the core part. Winding the winding wire in a portion of the outer peripheral surface of the coil in the stacking direction means that one of the winding wire parts constituting a portion of the outer peripheral surface of the coil is bent in the stacking direction. In this feature, the portion of the outer peripheral surface of the coil covering a plane of the core part means the portion of the outer peripheral surface of the coil that overlaps a plane of the core part on the outer peripheral surface of the coil as viewed in the stacking direction.

In the coil part of the present invention, a portion of the coil other than a crossing point and a boundary between a crossing point and a parallel region may be a parallel region or a region other than a parallel region. The region other than a parallel region here is, for example, a region that was a parallel region when the winding wire was wound into the coil but is no longer a parallel region after isostatic pressing.

The coil part of the present invention is characterized in that, in each portion of the coil part that is orthogonal to the circumferential direction and passes through the intersection point, a plurality of winding wire parts, other than the plurality of winding wire parts positioned at the end in the axial direction of the coil, do not include winding wire parts having recesses at two opposite positions on the outer edge that are in contact with the adjacent winding wire parts. In this feature, the plurality of winding wire parts, other than the plurality of winding wire parts positioned at the end in the axial direction of the coil, means the plurality of winding wire parts positioned between the plurality of winding wire parts positioned at one end in the axial direction of the coil and the plurality of winding wire parts positioned at the other end in the axial direction of the coil. In this feature, the winding wire part having recesses at two opposite positions on the outer edge may be, for example, a winding wire part having a recess at two intersection points between a line passing through the approximate center of the intersection of the winding wire part and the outer edge of the winding wire part. The winding wire part having recesses at two opposite positions on the outer edge may, for example, be a winding wire part which, when the section of the winding wire part is divided into a first region containing the first recess, which is one of the two recesses, and a second region having the same area as the first region, has two recesses, wherein the second recess, which is the other of the two recesses, is always present in the second region and the second recess is not present in the first region.

When the number of a particular component is not clearly specified in the claims and that component is indicated in the singular when translated into English, the present invention may comprise a plurality of those components. The present invention may also comprise only one of those components.

In the present invention and embodiments, the terms “including,” “having,” “providing,” and their derivatives are used to include additional components in addition to the enumerated components and their equivalents.

Unless otherwise defined, all terms (including technical and scientific terms) used in this document description and in the claims have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention relates. Terms as defined in commonly used dictionaries should be construed to have a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and not to have an idealized or overly formal meaning.

In this specification, the term "may also do" is not exclusive. The term "may also do" means that something "may also be done, but is not limited to that". In this specification, the term "may also do" implicitly includes the fact that something is not done.

Before embodiments of the present invention are explained in detail, it should be understood that the present invention is not limited to the details of the construction and arrangement of the components given in the following explanation or shown in the drawings. The present invention is also possible in embodiments other than those described below. The present invention is also possible in embodiments with various modifications of the embodiments described below.

EFFECTS OF THE INVENTION

According to the method for manufacturing the coil part and the coil part of the present invention, at least the crossing point of the coil can be pressed and the electrical resistance of the coil can be reduced.

BRIEF EXPLANATION OF THE DRAWINGS

• 1 shows a schematic diagram illustrating a first embodiment of a method for producing a coil part of the present invention.
• 2 shows a schematic diagram illustrating a third embodiment of the method for manufacturing the coil part of the present invention.
• 3 shows a schematic representation of the coil part manufactured according to a fourth embodiment of the method for manufacturing the coil part of the present invention.
• 4 shows a schematic representation of an embodiment (a fifth embodiment) of the coil part of the present invention.
• 5(a) and 5(b) show sectional views in embodiments of the coil part of the present invention, and 5(c) shows a sectional view of the coil part of a comparative example.
• 6 shows a representation of a crossing point of a coil formed by winding a winding wire with a rectangular sectional shape.

EMBODIMENTS OF THE INVENTION

<First Embodiment>

A first embodiment, which is an embodiment of a method for manufacturing a coil part of the present invention, will be described with reference to 1 explained. The coil part 1 of the present embodiment has at least one coil 10 and a core element 30. The core element 30 comprises at least one core part 31, which is arranged in the interior of the at least one coil 10. The number of coils 10 and core parts 31 that the coil part 1 has in 1 is one in each case, but the majority of them is also possible. The sectional shape of the core part 31 in 1 is rectangular, but the sectional shape of the core part 31 is not particularly limited. The core part 31 is formed of compressible material.

The method for manufacturing the coil part 1 of the present invention comprises a winding step and an isostatic pressing step. In the winding step, a winding wire 20 is wound in multiple layers on the core part 31 to form at least one coil 10. In 1 the number of layers of the coil 10 is four, but can also be more or less than four. The coil 10 has a crossing point 11 in a section of the circumferential direction, at which adjacent winding wire parts 21 cross each other in the stacking direction, viewed in the stacking direction. The sectional shape of the winding wire 20 in the winding step of 1 is circular, however, the sectional shape of the winding wire 20 in the winding step of the present embodiment may also be rectangular.

The isostatic pressing step is carried out after the winding step. In the isostatic pressing step, at least the crossing point 11 of the at least one coil 10 in the state in which the core part 31 is arranged inside the at least one coil 10 is pressed together with the core element 30 by isostatic pressing.

The isostatic pressing performed in the isostatic pressing step is isostatic pressing using at least one of a liquid pressure medium, a gaseous pressure medium, and an elastic solid pressure medium.

1(a) shows an example of a situation in which isostatic pressing is carried out with at least one liquid pressure medium. Isostatic pressing in 1(a) is, for example, wet cold isostatic pressing (WET CIP). In 1(a) the coil 10 and the core element 30 are enclosed in a flexible bag 53 which is placed in a liquid pressure medium 52 in a pressure vessel 51, and the pressure medium 52 is pressurized. However, when only a portion in the circumferential direction of the coil 10 is pressed, the portion in the circumferential direction of the coil 10 which is not to be pressed is covered with a lid. A vacuum preferably prevails inside the bag 53, but air may also remain. The bag 53 may or may not be made of rubber.

1(b) shows an example of a situation in which isostatic pressing is carried out with at least one gaseous pressure medium. Isostatic pressing in 1(b) is, for example, hot isostatic pressing (HIP). The coil 10 and the core element 30 are enclosed in a flexible bag 63, this bag 63 is placed in a pressure vessel 61, and a gaseous pressure medium 62 in the pressure vessel 61 is pressurized. However, when only a portion in the circumferential direction of the coil 10 is pressed, the portion in the circumferential direction of the coil 10 that is not to be pressed is covered with a lid. A vacuum preferably prevails inside the bag 63, but air may also remain. The bag 63 may or may not be made of rubber.

1(c) shows an example of a situation in which isostatic pressing is carried out with at least one liquid pressure medium and one elastic solid pressure medium. Isostatic pressing in 1(c) is, for example, wet cold isostatic pressing (WET CIP). A rubber mold 73 in which the coil 10 and the core element 30 are arranged is enclosed in a flexible bag 74, and the bag 73 is placed in a liquid pressure medium 72 in a pressure vessel 71, and the pressure medium 72 is pressurized. However, when only a portion in the circumferential direction of the coil 10 is pressed, the portion in the circumferential direction of the coil 10 not to be pressed is covered with a lid. A vacuum is preferably maintained inside the bag 73, but air may also remain. The rubber mold 73 corresponds to a solid pressure medium with elasticity. A bag made of rubber may also be used instead of the rubber mold 73 and the bag 74.

1(d) shows an example of a situation in which isostatic pressing is carried out with at least one elastic solid pressure medium. The isostatic pressing in 1(d) is rubber isostatic pressing (RIP). The coil 10 and the core member 30 are placed in a rubber mold 82 which is placed in a pressure vessel 81, and the rubber mold 82 is directly pressurized by a piston of the pressure vessel 81. However, when only a portion in the circumferential direction of the coil 10 is pressed, the portion in the circumferential direction of the coil 10 not to be pressed is covered with a lid. The rubber mold 82 corresponds to a solid pressure medium having elasticity.

In 1(e) and 1(f) Two examples are shown for situations in which isostatic pressing is carried out with at least one liquid pressure medium and one elastic solid pressure medium. The isostatic pressing of the 1(e) and 1(f) is, for example, cold isostatic dry pressing (DRY CIP). The interior of a pressure vessel 91 of the 1(e) and 1(f) is divided by a pressure rubber mold 93 into a space in which a liquid pressure medium 92 is arranged and a space in which a molded rubber mold 94 is arranged. The coil 10 and the core element 30 are arranged in the molded rubber mold 94 and are subjected to the pressure of the pressure medium 92 via the molded rubber mold 94 and the pressure rubber mold 93. When only a portion in the circumferential direction of the coil 10 is pressed, the portion in the circumferential direction of the coil 10 not to be pressed is covered with a lid.

The method for pressurizing the gaseous or liquid pressure medium in the pressure vessels 51, 61, 71, 91 can, for example, consist in the pressure medium being inserted into the pressure vessels 51, 61, 71, 91 with the aid of a pressure intensifier, or in the pressure medium being pressurized by the piston of the pressure vessel 51, 61, 71, 91.

According to the method of manufacturing the coil part 1 according to the present embodiment, the sectional area of the winding wire 20 does not become locally small even though at least the crossing point 11 of the coil 10 is pressed, and furthermore, the sectional area of the winding wire 20 at least at the crossing point 11 can be larger than before pressing. Therefore, the electric resistance of the coil 10 can be reduced.

According to the method for manufacturing the coil part 1 of the present embodiment, the following other effects can be obtained. Since deformation of the winding wire 20 such that the sectional area of the winding wire 20 is locally small does not occur, damage to the insulating film of the winding wire 20 can be suppressed.

When the crossing point 11 is pressed by a mold, the gap between adjacent winding wire parts 21 in the axial direction CA of the coil at the crossing point 11 can be large. In contrast, according to the method of manufacturing the coil part 1, the disturbance of the position of the winding wire 20 at the crossing point 11 can be suppressed. Therefore, the gap between the winding wire parts 21 at the crossing point 11 and the gap between the winding wire parts 21 and the core part 31 at the crossing point 11 can be smaller than when the crossing point 11 is pressed by a mold. Therefore, the coil part 1 can be made small than when the crossing points 11 are pressed by a mold. In addition, the thermal conductivity of the coil part 1 can be improved compared with when the crossing points 11 are pressed by a mold. In addition, the leakage flux of the coil part 1 can be suppressed compared with the case where the crossing points 11 are pressed by a mold.

As in 1 For example, as shown, the core member 30 may have two edge portions 32 facing each end of the axial direction CA of the crossing point 11 and the axial direction CA of the coil. It is not possible to press the crossing point 11 by a mold in the axial direction CA of the coil when the core portion 31 is disposed inside the coil 10 and the crossing point 11 is disposed between the two edge portions 32. Therefore, in this case, the gap between the winding wire portions 21 of adjacent layers at the crossing point 11 and the gap between the winding wire portions 21 and the core portion 31 at the crossing point 11 may be smaller than before pressing, but the gap between the winding wire portions 21 of the same layer at the crossing point 11 cannot be reduced. In contrast, after the isostatic pressing step of the method of manufacturing the coil part 1 according to the present embodiment, even if the core member 30 has two edge parts 32 facing each end in the coil axial direction CA in the coil axial direction CA at the crossing point 11, the gap between the winding wire parts 21 of the adjacent layer at the crossing point 11 and the gap between the winding wire parts 21 and the core part 31 at the crossing point 11 and the gap between the winding wire parts 21 of the same layer at the crossing point 11 can be smaller than before the pressing. Therefore, when the core member 30 has two edge parts 32, the difference in thermal conductivity of the coil part 1 between the method of manufacturing the coil part 1 of the present embodiment and the pressing of the crossing point 11 by a mold is larger.

In the present embodiment, the pressing force when pressing at least the crossing point 11 of the coil 10 together with the core member 30 by isostatic pressing is not particularly limited. The pressing force is preferably such that the sectional area of the winding wire 20 of at least the crossing point 11 of the coil 10 can become larger than before pressing. The pressing force may be, for example, 10 MPa or more, 20 MPa or more, or 30 MPa or more. When the conductor of the winding wire 20 is made of aluminum or an aluminum alloy, the pressing force may be, for example, 10 MPa or more. When the conductor of the winding wire 20 is made of copper or a copper alloy, the pressing force may be, for example, 20 MPa or more. When the sectional shape of the winding wire 20 in the winding step is circular, a pressing force large enough to keep the sectional shape of the winding wire 20 in a circular shape may be sufficient.

The method for manufacturing the coil part 1 according to the present embodiment may include a step of winding an insulating tape in which the insulating tape is wound on the outer peripheral surface of the coil 10 after the winding step and before the isostatic pressing process. The insulating tape may be impregnated with a thermosetting resin beforehand. The thermosetting resin may be impregnated into the insulating tape after winding the insulating tape. The insulating tape may not be impregnated with thermosetting resin either. Both the insulating tape and the thermosetting resin have insulating properties. The thermosetting resin may be a resin that can be cured only at temperatures above normal temperature or a resin that can be cured at normal temperature. At least the crossing point 11 of the coil 10 is pressed by isostatic pressing, which increases the adhesion between the insulating tape and the coil 10 and thus improves the insulating properties of the coil 10. Further, when a liquid or gaseous pressure medium having a temperature higher than normal temperature is used in the isostatic pressing, the curing of the thermosetting resin can be accelerated. The method for producing the coil part 1 of the present embodiment also does not need to include such a step of winding the insulating tape.

In the present embodiment, if the inside of the coil 10 in the core element 30 arranged portion is only the cylindrical core part 31, the isostatic pressing in the isostatic pressing step can be performed in the state where the interior of the core part 31 is filled with, for example, rubber. By doing so, isostatic pressing can be applied to the inner surface of the core part 31 while suppressing deformation of the core part 31 which causes a portion of the inner surface of the core part 31 to protrude or the inner diameter of the core part 31 to be reduced. The case where the portion of the core member 30 arranged inside the coil 10 is only the cylindrical core part 31 is, for example, the case where the coil part 1 is used in a stator of a rotating electrical machine and the core member 30 is an insulating bobbin.

<Second Embodiment>

A second embodiment, which is an embodiment of the method for manufacturing the coil part of the present invention, will now be explained. The second embodiment has the following configurations in addition to the embodiment of the first embodiment. In the isostatic pressing step in the method for manufacturing the coil part 1 of the present embodiment, the entire circumference of the coil 10 in the state where the core part 31 is arranged inside the coil 10 is pressed together with the core member 30 by isostatic pressing. The pressing force in isostatically pressing the entire circumference of the coil 10 together with the core member 30 is not particularly limited. When the sectional shape of the winding wire 20 in the winding step is circular, by increasing the pressing force in isostatic pressing, the sectional shape of the winding wire part 21 surrounded by the six winding wire parts 21 eventually deforms into a hexagon in a portion in the circumferential direction of the coil 10 other than the crossing point 11. The pressing force may be less than the pressing force at which the sectional shape of the winding wire part 21 surrounded by the six winding wire parts 21 is deformed into a hexagon. When the sectional shape of the winding wire 20 in the winding step is circular, a pressing force large enough to keep the sectional shape of the winding wire 20 in a circular shape may be sufficient.

<Third Embodiment>

A third embodiment, which is an embodiment of the method for manufacturing the coil part of the present invention, will be described with reference to 2 The third embodiment has the following configurations in addition to the configuration of the second embodiment. The core part 31 of the present embodiment includes at least a portion of each of a plurality of parts arranged side by side in a direction crossing the coil axial direction CA and mechanically connected. The coil part 1 of 2 is the coil part 1 used in a stator of an outer rotor or inner rotor type rotating electric machine, but the application of the coil part 1 of the present embodiment is not limited thereto. The coil part 1 of the present embodiment may also be a coil part 1 used in a stator of an axial gap type rotating electric machine or other electric equipment.

The core element 30 of 2 is formed of an insulating bobbin 41 and a stator core part 43 which is a portion of the stator core. The core part 31 may be a portion of the insulating bobbin 41. Alternatively, the core part 31 may be formed of a portion of the insulating bobbin 41 and a portion of the stator core part 43 which is arranged inside the insulating bobbin 41. The stator core part 43 is formed of a plurality of electromagnetic steel plates 44. The plurality of electromagnetic steel plates 44 are aligned in a direction orthogonal to the coil axial direction CA. The plurality of electromagnetic steel plates 44 are mechanically connected to each other by caulking. Concretely, the plurality of electromagnetic steel plates 44 are connected by fitting projections formed on adjacent electromagnetic steel plates 44 into recesses formed on the electromagnetic steel plates 44. The insulating bobbin 41 is formed of two bobbin parts 42. The stator core part 43 is arranged between two coil bobbin parts 42. The direction in which the two coil bobbin parts 42 are aligned is the same as the direction in which the plurality of electromagnetic steel plates 44 are aligned. The coil bobbin parts 42 and the stator core parts 43 may be unconnected to each other or may be mechanically connected by caulking or other means. The core part 31 of 2 comprises at least a portion of each of a plurality of parts 44, 44, ... (or a plurality of parts 42, 42, 44, 44, 44...) arranged side by side and mechanically connected in a direction orthogonal to the axial direction CA of the coil.

By having the core part 31 comprise at least a portion of each of the plurality of parts arranged side by side and mechanically connected in a direction crossing the axial direction CA of the coil, the length of the core part 31 in the direction crossing the axial direction CA of the coil can be shortened by isostatic pressing. Therefore, the circumferential length of the inner and outer circumferences of the coil 10 can be further shortened. As a result, the sectional area of the winding wire 20 can be further increased and the electrical resistance of the coil 10 can be further reduced. In addition, the length of the core part 31 and the coil 10 in the direction crossing the axial direction CA of the coil can be shortened, so that the coil part 1 can be made smaller. By increasing the sectional area of the winding wire 20, the gap between the winding wire parts 21 and the gap between the winding wire part 21 and the core part 31 can be further reduced. Therefore, the thermal conductivity of the coil part 1 can be improved and the leakage flux of the coil part 1 can be further suppressed.

<Fourth Embodiment>

A fourth embodiment, which is an embodiment of the method for manufacturing the coil part of the present invention, will be described with reference to 3 explained. The fourth embodiment has the following configurations in addition to at least one of the first to third embodiments. The coil part 1 of the present embodiment has the core member 30 having a plurality of core parts 31 and a plurality of coils 10. In the winding step in the method for manufacturing the coil part 1 of the present embodiment, a plurality of coils 10 are formed by winding the plurality of winding wires 20 on the plurality of core parts 31 in multiple layers, respectively. Each coil 10 has the crossing point 11 in a portion of the circumferential direction. In the isostatic pressing step in the method for manufacturing the coil part 1, at least the crossing point 11 of the plurality of coils 10 in the state where the plurality of core parts 31 are arranged inside the plurality of coils 10, respectively, is pressed together with the core member 30 by isostatic pressing.

As in 3 As shown, the core member 30 of the present embodiment may be, for example, an annular member. The plurality of core parts 31 may be provided along the circumferential direction of the core member 30. The coil part 1 of 3 is a coil part 1 used in a stator of an external rotor type rotating electric machine, but the application of the coil part 1 of the present embodiment is not limited thereto. The coil part 1 of the present embodiment may also be a coil part 1 used in a stator of an internal rotor type rotating electric machine, a stator of an axial gap type rotating electric machine, or other electrical equipment. The core element 30 of 3 is formed of a stator core 40 and a plurality of insulating bobbins 41. The core part 31 may be a portion of the insulating bobbin 41. Alternatively, the core part 31 may be formed of a portion of the insulating bobbin 41 and a portion of the stator core 40 disposed inside the insulating bobbin 41. The structure of the core part 31 may be the same as the structure of the core part 31 in 2 . The stator core 40 may be integral or split. The stator core 40 is an annular member. The plurality of insulating coils 41 are arranged on the outer circumference of the stator core 40 along the circumferential direction of the stator core 40.

When the core member 30 is an annular member, isostatic pressing may be performed in the isostatic pressing step with the interior of the annular core member 30 filled with, for example, rubber. By doing so, isostatic pressing can be applied to the inner peripheral surface of the core member 30 while suppressing deformation of the core member 30 that causes a portion of the inner peripheral surface of the core member 30 to protrude or the inner diameter of the core member 30 to be reduced.

<Fifth Embodiment>

A fifth embodiment, which is an embodiment of the coil part of the present invention, will be described with reference to 4 explained. The coil part 1 of the present embodiment has a coil 10 and a core element 30 which comprises a core part 31 arranged inside the coil 10. The coil 10 is formed from the winding wire 20 which is wound in multiple layers on the core part 31. In 4(a) and 4(c) to 4(e) the number of layers of the coil 10 is four, but may be more or less than four. The end of the winding wire 20 which is not wound on the core part 31 is referred to as the extension part 22. As in 4(b) , the sectional shape of the extension part 22 is circular. That is, the sectional shape of the winding wire 20 is circular when the winding wire 20 is wound on the core part 31. In the coil part 1, the sectional shape of the part of the winding wire 20 except the end may or may not be circular. However, the shape of the surface of the winding wire part 21 which forms the outer peripheral surface of the coil 10 is circular. As shown in 4(a) As shown in FIG. 1, the coil 10 has a crossing point 11 in a section of the circumferential direction, at which adjacent winding wire parts 21, viewed in the stacking direction, cross. As shown in FIG. 4(c) As shown, the coil 10 has, in another portion of the circumferential direction, a parallel region 12 in which the winding wire parts 21 of the upper layer are arranged along the groove formed by the winding wire part 21 of the lower layer.

The sectional shape of the core part 31 is not particularly limited. The core part 31 is formed of compressible material. The core part 31 is not molded integrally with the coil 10. Therefore, the core part 31 is not a core part that is molded after the entire circumference of the coil 10 is pressed by isostatic pressing in the state where nothing is arranged inside the coil 10.

As in 4(f) , the outer peripheral surface of the core part 31 may have, for example, two parallel planes 33a, 33b. When the outer peripheral surface of the core part 31 has two parallel planes 33a, 33b, these two planes 33a, 33b are in contact with the winding wire 20. Therefore, the core part 31 is not a core part that is arranged inside the coil 10 after the entire circumference of the coil 10 is pressed by isostatic pressing in the state where nothing is arranged inside the coil 10. For example, as shown in 4 (f) As shown, for example, these two planes 33a, 33b can be in contact with the winding wire 20 in a section orthogonal to the axial direction CA of the coil. In 4(f) only the winding wire part 21 of the lowest layer of the winding wire 20 is shown.

As in 4(g) As shown, the outer peripheral surface of the core part 31 may, for example, have two non-parallel planes instead of two parallel planes. In 4(g) the planes 34a, 34b are not parallel, the planes 34b, 34c are not parallel, and the planes 34c, 34a are not parallel. Although not shown, the outer peripheral surface of the core part 31 may also have two non-parallel planes and a curved surface instead of two parallel planes. When the outer peripheral surface of the core part 31 has two non-parallel planes instead of two parallel planes, one of the two non-parallel planes of the outer peripheral surface of the core part 31 and a corner that is not an end of this plane are in contact with the winding wire 20, or the curved surface of the outer peripheral surface of the core part 31 and a corner that is not an end of this curved surface are in contact with the winding wire 20. In the example of 4(g) the plane 34a and the corner 35, which is not an end of this plane 34a, are in contact with the winding wire 20. Therefore, the core part 31 is not a core part that is arranged inside the coil 10 after the entire circumference of the coil 10 is pressed by isostatic pressing in the state where nothing is arranged inside the coil 10. In a section orthogonal to the axial direction CA of the coil, flat or curved surfaces and a corner may be in contact with the winding wire 20 (see, for example, FIG. 1). 4(g) ). In 4(g) only the winding wire part 21 of the lowest layer of the winding wire 20 is shown.

As in 4(h) , the sectional shape of the core part 31 may be, for example, circular or elliptical. When the sectional shape of the core part 31 is circular or elliptical, three or more points P including both ends in the circumferential direction in the range 36 of 180° or more on the outer peripheral surface of the core part 31 are in contact with the winding wire 20. Therefore, the core part 31 is not a core part that is arranged inside the coil 10 after the entire circumference of the coil 10 is pressed by isostatic pressing in the state where nothing is arranged inside the coil 10. As shown in 4(h) For example, in a section orthogonal to the axial direction CA of the coil, three or more points P, including the two ends of the circumferential direction inside the region 36, may be in contact with the winding wire 20. In 4(h) only the winding wire part 21 of the lowest layer of the winding wire 20 is shown.

As in 4(i) As shown, when the outer peripheral surface of the core part 31 has a plane 37, the winding wire 20 is bent in the portion covering the plane 37 on the outer peripheral surface of the coil 10 such that a plurality of concave depressions 23 in the stacking direction are adjacent to one another in the circumferential direction. The coil 10 is therefore not a coil that is not pressed at all. The coil 10 is also not a coil 10 in which only a portion in the circumferential direction of the coil 10 apart from the crossing point 11 is pressed by the mold. The plane 37 can be, for example, the plane 33a or the plane 33b of 4(f) Level 37 can be, for example, one of the levels 34a to 34c in 4(g) As in 4(i) For example, in a section orthogonal to the axial direction CA of the coil, several recesses 23 concave in the stacking direction can be located next to one another in the section covering the plane 37 on the outer peripheral surface of the coil 10. As shown, for example, in 4(i) As shown, the winding wire portion 21a of the outermost layer wound on the plane 37 may be bent to form the plurality of recesses 23.

If the sectional shape of the core part 31 is, for example, circular or elliptical, as in 4(j) As shown in FIG. 1, the winding wire 20 is bent in the axial direction CA of the coil in a portion of the coil 10 which is neither the crossing point 11 nor the boundary between the crossing point 11 and the parallel region 12. The coil 10 is therefore not a coil which is not pressed at all. The coil 10 is also not a coil in which only a portion in the circumferential direction of the coil 10 other than the crossing point 11 is pressed by the mold. As shown in FIG. 4(j) For example, as shown, several winding wire parts 21 aligned in the axial direction CA of the coil can be arranged in a section of the coil 10 which is neither the crossing point 11 nor the boundary between the crossing point 11 and the parallel region 12, in the axial direction CA of the coil, wherein the winding wire part 21 is in contact with the adjacent winding wire part 21. These multiple winding wire parts 21 can consist of two winding wire parts 21 or of three or more winding wire parts 21.

Such as in 4(d) and 4(e) As shown, the plurality of winding wire parts 21, except for the winding wire parts 21 positioned at the end of the axial direction CA of the coil, in each section orthogonal to the circumferential direction of the coil part 1 and passing through the crossing point 11, do not include the winding wire part 21 having a recess in contact with the adjacent winding wire part 21 at two opposite positions on the outer edge. The coil 10 is therefore not a coil in which the crossing point 11 is pressed by a mold. The point Q in 4(e) shows a point at which the winding wire parts 21 of the adjacent layers are in point contact at the crossing point 11. If the crossing point 11 is pressed by a mold, the force acts intensively on the point at the crossing point 11 at which the winding wire parts 21 are in point contact, so that the sectional shape of the winding wire part 21 at the position that is not at the axial end of the coil 10 at the crossing point 11 is easily deformed, so that depressions are present at two opposite points on the outer edge. The sectional area of the winding wire part 21 deformed in this way is smaller than the sectional area of the other winding wire part 21.

Therefore, the coil part 1 of the present embodiment is a coil part 1 obtained by pressing the entire circumference of the coil 10 with the crossing point 11 in the state where the core part 31 is arranged inside the coil 10 together with the core member 30 by isostatic pressing. The coil part 1 of the present embodiment can be manufactured, for example, in the method for manufacturing the coil part 1 of the second or third embodiment. Although the entire circumference of the coil 10 with the crossing point 11 is pressed, the sectional area of the winding wire 20 is not locally reduced, and the sectional area of the winding wire 20 can be larger than before pressing. The electric resistance of the coil 10 of the coil part 1 can therefore be reduced. In addition, since deformation of the winding wire 20, which leads to local reduction of the sectional area of the winding wire 20, does not occur, damage to the insulating film of the winding wire 20 can be suppressed.

The coil part 1 of the present embodiment may further have the following features. As shown in 4(d) and 4(e) , in each section orthogonal to the circumferential direction of the coil part 1 and passing through the crossing point 11, each of the plurality of winding wire parts 21, except for the plurality of winding wire parts 21 positioned at the end of the coil axial direction CA, is adjacent to the coil in the coil axial direction CA and is in contact with the winding wire part 21 not positioned at the end of the coil axial direction CA. Since the disturbance of the position of the winding wire 20 is suppressed in this way, deformation of the winding wire 20 such that the sectional area of the winding wire 20 at the crossing point 11 is locally reduced during pressing is less likely. In addition, since the disturbance of the position of the winding wire at the crossing point 11 is suppressed, the gap between the winding wire parts 21 at the crossing point 11 and the gap between the winding wire part 21 and the core part 31 at the crossing point 11 can be smaller than when the crossing point 11 is pressed by a mold. Therefore, compared with when the crossing points 11 are pressed by a mold, the coil part 1 can be made smaller, the thermal conductivity of the coil part 1 can be improved, and the leakage magnetic flux of the coil part 1 can be suppressed.

The outer peripheral surface of the coil 10 of the coil part 1 of the present embodiment may be covered with insulating tape or insulating tape and thermosetting resin, or may not be covered.

The 5(a) and 5(b) are images of sections of the crossing points of the coil parts of the two embodiments 1, 2 of the present invention. 5(c) is a picture of a section of the crossing point of the coil part in Comparative Example. The entire circumference of the coil in Comparative Example is pressed by a mold in the state where the core part is arranged inside the coil. The coil in Embodiment 2 is isostatically pressed with a higher pressing force than the coil in Embodiment 1. The configuration of the coils before pressing in Embodiment 1, Embodiment 2 and Comparative Example is the same. The coil parts in Embodiment 1, Embodiment 2 and Comparative Example are cut at the crossing point after the winding wires are coated with resin to prevent the movement of the winding wires. As in 5(c) As shown, in the section of the crossing point in the comparative example, there is a winding wire part 901 which has recesses 902 at two opposite positions on the outer edge. The two recesses 902 of the winding wire part 901 are in contact with the adjacent winding wire parts. The winding wire part 901 is a winding wire part which is not at the end in the axial direction CA of the coil is arranged. In 5(c) the maximum length of the cut of the winding wire part 901 is larger than the maximum length of the cut of the other winding wire parts. This is because the position of the winding wire part 901 is moved by pressing and the inclination of the winding wire part 901 in the direction of the line longitudinal direction relative to the circumferential direction of the coil increases. As shown in 5(a) and 5(b) As shown, in the section of the crossing point in embodiments 1, 2 there is no winding wire part which has recesses at two opposite positions on the outer edge.

BRIEF EXPLANATION OF THE REFERENCE SIGNS

1

coil part

10

Sink

11

intersection point

12

parallel area

20

winding wire

21

winding wire part

22

pull-out part

30

core element

31

core part

33a, 33b, 34a, 34b, 34c, 37

level

35

Corner

36

Area

CA

axial direction of the coil

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• JP 2007-288983 A [0004]

Claims (9)

A method of manufacturing a coil part comprising a coil and a core element comprising a core part arranged inside the coil, characterized by : a winding step in which a winding wire is wound in multiple layers on the core part to form the coil having an intersection point at which winding wire parts adjacent in a stacking direction cross each other as viewed in the stacking direction in a portion in the circumferential direction, and an isostatic pressing step in which at least the intersection point of the coil after the winding step is pressed together with the core element by isostatic pressing in the state in which the core part is arranged inside the coil. Method for producing the coil part according to claim 1 , characterized in that the core part is formed from a compressible material. Method for producing the coil part according to claim 1 or 2 , characterized in that in the isostatic pressing step, the entire circumference of the coil in the state where the core part is arranged inside the coil is pressed together with the core element by isostatic pressing. Method for producing the coil part according to claim 3 , characterized in that the core part comprises at least a portion of each of a plurality of parts which are arranged side by side in a direction crossing the axial direction of the coil and are mechanically connected. Method for producing the coil part according to one of the Claims 1 until 4 , characterized in that the coil part has a plurality of coils comprising the coil, the core element has a plurality of core parts comprising the core part, in the winding step, a plurality of winding wires are wound in multiple layers on the plurality of core parts to form the plurality of coils each having the crossing point in a portion in the circumferential direction, and in the isostatic pressing step, at least the crossing point of the plurality of coils in the state in which the plurality of core parts are arranged inside the plurality of coils is pressed together with the core element by isostatic pressing. Method for producing the coil part according to one of the Claims 1 until 5 , characterized in that in the winding step, a winding wire having a circular sectional shape is wound to form a coil. Method for producing the coil part according to one of the Claims 1 until 6 , characterized in that the isostatic pressing performed in the isostatic pressing step is isostatic pressing using at least one of a liquid pressure medium, a gaseous pressure medium and an elastic solid pressure medium. Coil part with a coil and a core element comprising a core part arranged inside the coil, characterized in that the coil is formed with a winding wire wound in multiple layers on the core part, the sectional shape of the end of the winding wire, which is an extension part not wound on the core part, is circular, the coil has a crossing point in one section in the circumferential direction at which adjacent winding wire parts cross each other in the stacking direction, seen in the stacking direction, and the coil has a parallel region in another section in the circumferential direction in which the winding wire part of the upper layer is arranged along the groove formed by the winding wire part of the lower layer, the core part is not formed integrally with the coil, if the outer peripheral surface of the core part has two parallel planes, the two parallel planes are in contact with the winding wire, and if the outer peripheral surface of the core part does not have two parallel planes but has two non-parallel planes, one of the two planes of the outer peripheral surface of the core part and a corner that is not an end of this plane are in contact with the winding wire, or a curved surface of the outer peripheral surface of the core part and a corner that is not an end of this curved surface are in contact with the winding wire, and a plane or a curved surface of the outer peripheral surface of the core part and a corner that is not an end of this plane or curved surface are in contact with the winding wire, and, when the sectional shape of the core part is circular or elliptical, three or more points including the two ends in the circumferential direction in the range of 180° or more on the outer peripheral surface of the core part are in contact with the winding wire, when the outer peripheral surface of the core part has a plane, the winding wire is bent such that a plurality of concave depressions in the stacking direction are formed in the portion of the outer peripheral surface the coil covering the one plane of the core part are adjacent to each other in the circumferential direction, and when the sectional shape of the core part is circular or elliptical, the winding wire is bent in the axial direction of the coil in a portion of the coil which is neither an intersection point nor a boundary between the intersection point and the parallel region, and, in each section which is orthogonal to the circumferential direction of the coil part and passes through the intersection point, the plurality of winding wire parts, other than the plurality of winding wire parts positioned at the end in the axial direction of the coil, do not include a winding wire part which has recesses in contact with adjacent winding wire parts at two opposite positions on the outer edge. coil part after claim 8 , characterized in that in each section which is orthogonal to the circumferential direction of the coil part and passes through the crossing point, each of the plurality of winding wire parts, except for the plurality of winding wire parts positioned at the end in the axial direction of the coil, is in contact with winding wire parts which are adjacent in the axial direction of the coil and are not positioned at the end in the axial direction of the coil.

Images