Terminal connection method for litz wire

1. A terminal connecting method for a litz wire for electrically connecting a terminal metal fitting to the litz wire comprising:

providing the terminal metal fitting and the litz wire, the terminal metal fitting having a pressure fixing part having a cylindrical shape, the litz wire being obtained by twisting together a plurality of strands each composed of a conducting body and an insulation coating provided on an outer peripheral surface of the conducting body;

removing the insulation coating by a predetermined length from one end of the litz wire;

inserting along the axial direction to a through hole of the pressure fixing part a terminal part of the litz wire from which the insulation coating is removed;

compressing a first portion of the pressure fixing part with a first compression force to cause plastic deformation of an entirety of the pressure fixing part, and to temporarily fix the terminal part of the litz wire to the pressure fixing part;

compressing a second portion of the pressure fixing part with a second compression force greater than the first compression force to locally cause plastic deformation of the pressure fixing part and the litz wire, the second portion being a part of the first portion; and

pouring molten solder from a front end side of the pressure fixing part to firmly fix the litz wire to the terminal metal fitting.

2. The terminal connecting method for a litz wire according to claim 1 , wherein the first compression force is 100 MPa to 1,000 MPa, both inclusive; and

wherein the second compression force is 1,000 MPa to 10,000 MPa, both inclusive.

3. The terminal connecting method for a litz wire according to claim 2 , wherein a length of the second portion in a width direction is 60% or greater of a length of the first portion in a width direction before the first portion is compressed.

4. The terminal connecting method for a litz wire according to claim 1 , wherein a rear edge of the second portion is located 1 to 2 mm inside from a rear end of the pressure fixing part.

5. The terminal connecting method for a litz wire according to claim 1 , wherein a front edge of the second portion is located 2 mm or more inside from a front end of the pressure fixing part.

6. The terminal connecting method for a litz wire according to claim 1 , wherein:

each strand of the litz wire has a diameter of 0.05 mm to 0.30 mm, both inclusive; and

a number of strands twisted together of the litz wire is 50 to 3,000, both inclusive.

7. The terminal connecting method for a litz wire according to claim 1 , wherein the insulation coating is made of a resin material which is removable in the pouring.

8. The terminal connecting method for a litz wire according to claim 1 , wherein a length of the second portion in a width direction is 60% or greater of a length of the first portion in a width direction before the first portion is compressed.