Manufacturing method for insulated electric wire and its manufacturing apparatus

1. A method of manufacturing an insulated electric wire comprising:

supplying a conductor to a conductor rolling process in a conductor feeding process;

rolling the conductor in the conductor rolling process in a predetermined shape;

rolling the conductor in a conductor wire drawing process with a pair of first rolling rolls rotating freely without a drive mechanism and passing the conductor through a die to wire-draw the conductor;

annealing the conductor wire-drawn in the conductor wire drawing process with a conductor annealing unit and supplying the conductor to a coat baking process:

forming an insulating coat on the conductor in the conductor baking process at a constant feeding speed to obtain the insulated electric wire; and

winding an electric wire in an electric wire winding process covered with the insulating coat in the coat baking process with an electric wire winding unit,

wherein, in the conductor rolling process, a pair of second rolling rolls is rotated with the drive mechanism to roll the conductor in the predetermined shape, and a distance between the second rolling rolls is variably controlled according to a change in a width of the conductor after rolling and according to the constant feeding speed of the conductor in the conductor baking process,

in the conductor rolling process, said second rolling rolls are rotated with the drive mechanism at a rotating speed variably controlled according to an elongation of the conductor in a longitudinal direction thereof after rolling and according to the constant feeding speed of the conductor in the conductor baking process, and

an entire process from the conductor feeding process to the electric wire winding process is conducted in a tandem arrangement.

2. The method of manufacturing an insulated electric wire according to claim 1 , said conductor is supplied to the pair of second rolling rolls at a speed variably controlled so that a variation in tension of the conductor is suppressed.

3. An apparatus for manufacturing an insulated electric wire, comprising:

a conductor feeding unit for supplying the conductor to a conductor rolling unit;

the conductor rolling unit for rolling a conductor in a predetermined shape;

a conductor wire drawing unit for rolling the conductor with a pair of first rolling rolls rotating freely without a drive mechanism and passing the conductor through a die to wire-draw the conductor in the predetermined shape;

a conductor annealing unit for annealing the conductor wire-drawn with the conductor wire drawing unit and supplying the conductor to the coat baking unit;

a coat baking unit for forming an insulating coat on the conductor at a constant feeding seed; and

an electric wire winding unit for winding an electric wire covered with the insulating coat with the coat baking unit,

wherein said conductor rolling unit includes a pair of second rolling rolls rotated with the drive mechanism to roll the conductor in the predetermined shape, the pair of second rolling rolls having a distance therebetween variably controlled according to a change in a width of the conductor after rolling and according to the constant feeding speed of the conductor,

said second rolling rolls are rotated with the drive mechanism at a rotating speed variably controlled according to an elongation of the conductor after rolling and according to the constant feeding speed of the conductor, and

an entire series from the conductor feeding unit to the electric wire winding unit is arranged in a tandem arrangement.

4. The apparatus for manufacturing an insulated electric wire according to claim 3 , wherein said conductor is supplied at a speed variably controlled according to a comparison result between the rotating speed of the second rolling rolls and the constant feeding speed of the conductor supplied to the second rolling rolls.

5. The method of manufacturing an insulated electric wire according to claim 1 , wherein, in the conductor rolling process, said conductor passes through the second rolling rolls after passing through a first dancer roll.

6. The method of manufacturing an insulated electric wire according to claim 1 , wherein, in the conductor rolling process, said conductor passes through the second rolling rolls before passing through a second dancer roll.

7. The method of manufacturing an insulated electric wire according to claim 1 , wherein, in the conductor rolling process, said second rolling rolls have the distance therebetween variably controlled according to the change in the width of the conductor monitored by a conductor dimension monitor.

8. The apparatus for manufacturing an insulated electric wire according to claim 3 , wherein said conductor rolling unit further includes a first dancer roll and a second dancer roll so that the second rolling rolls are situated between the first dancer roll and the second dancer roll.

9. The apparatus for manufacturing an insulated electric wire according to claim 3 , wherein said conductor rolling unit further includes a conductor dimension monitor for monitoring a dimension of the conductor.