TECHNICAL FIELD

The present invention relates to an armature coil for use in a rotary electric machine and a method of manufacturing the same and, more particularly, relates to the shape of the armature coil.

BACKGROUND ART

Hitherto, a coil wound around a stator or a rotor of a rotary electric machine passes through in line in slots that are holding portions for the coil. More particularly, there are disclosed a coil whose coil conductor cross-section is formed in a rectangular shape or a trapezoidal shape along the shape of the slot and a coil whose coil conductor shape is formed in a trapezoidal shape that is different depending on a slot insertion position. Furthermore, one side and the other side of the coil conductor are formed in parallel planes. (Refer to FIG. 12 of Patent Document 1.)

Moreover, in a conventional method of manufacturing a coil, there is disclosed one in which at least a portion of a coil to be inserted into a slot is inserted and arranged in a forming die having a previously determined trapezoidal shaped groove and a coil conductor is pressed by a pressing die to be formed in a trapezoidal shape. Furthermore, one side and the other side of the coil conductor are formed in parallel planes. (Refer to Patent Document 2.)

RELATED ART DOCUMENT

Patent Document

Patent Document 1: Japanese Patent Gazette No. 3474660 Patent Document 2: Japanese Examined Patent Publication No. H7-32551

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

Even if the above-described conventional armature coil and method of manufacturing the same, a space factor is improved by deforming to the coil conductor shape along the slot shape. However, further high output of the rotary electric machine is required in recent years; and a problem exists in that the space factor needs to be further improved.

The present invention has been made to solve the above described problem, and an object of the present invention is to provide an armature coil and a method of manufacturing the same, which can further improve a space factor.

Means for Solving the Problems

According to the present invention, there is provided an armature coil in which a plurality of slots through which coil conductors pass are annularly arranged and a plurality of the coil conductors pass through the inside of the slot in line. In the armature coil, the circumferential width of the plurality of the coil conductors is formed in a substantially trapezoidal shape which gets narrower toward the radially inner side and the cross-sectional areas of the plurality of the coil conductors in the slot are each substantially the same and the circumferential width thereof is formed narrower as the coil conductor is arranged toward the radially inner side; and one coil conductor is formed in a convex shape and another coil conductor is formed in a concave shape along the convex shape.

Furthermore, according to the present invention, there is provided a method of manufacturing an armature coil including the steps of: arranging a plurality of coil conductors on a lower metal die having a taper-shaped groove substantially the same as a slot which is wound with the plurality of the coil conductors of the armature coil and is formed in a trapezoidal shape which gets narrower in width toward the radially inner side; pressing the coil conductors arranged in the groove of the lower metal die by an upper metal die having a rod-shaped end portion slightly narrower than the width of the groove; forming more flattened toward the coil conductor arranged at the end of the groove by being pressed to a predetermined position by the rod-shaped end portion of the upper metal die, forming an aspect ratio smaller toward the coil conductor near an opening portion of the groove, and forming such that one coil conductor is formed in a convex shape and another coil conductor is formed in a concave shape along the convex shape at between the coil conductors; and removing the coil conductors formed in the convex shape and the concave shape from the lower metal die.

Further, according to the present invention, there is provided a method of manufacturing an armature coil, including the steps of: having a lower metal die which is provided with an end metal die at a left end portion and a back portion metal die at a right end portion and an upper metal die which is provided with an inclined portion on the lower metal die side and is to be pressed, forming such that a space formed by the respective metal dies is substantially the same as the shape of a slot and the width of the space gets gradually narrower toward the direction of the end metal die when the upper metal die is moved to come in contact with the upper surfaces of the end metal die and the back portion metal die of the lower metal die, and arranging a plurality of coil conductors of the armature coil between the end metal die and the back portion metal die on the lower metal die; pressing the plurality of the coil conductors arranged between the end metal die and the back portion metal die on the lower metal die by the upper metal die; forming more flattened toward the coil conductor near the end metal die by being pressed to a position coming in contact with the upper surfaces of the end metal die and the back portion metal die of the lower metal die by the upper metal die, forming an aspect ratio smaller toward the coil conductor near the back portion metal die, and forming such that one coil conductor is formed in a convex shape and another coil conductor is formed in a concave shape along the convex shape at between the coil conductors; and removing the coil conductors formed in the convex shape and the concave shape from the lower metal die.

Advantageous Effect of the Invention

According to the present invention, the degree of joining between the coil conductors is increased by forming the shape of a coil conductor cross-section in the slot in concave and convex shapes and thereby improving a space factor, whereby, as a result, there can be provided the armature coil of a high output rotary electric machine.

