Hitachi Metals, Ltd.

Hitachi Magnet Wire Corp.

Masayoshi Goto

Seigi Aoyama

Toru Sumi

Takahiro Sato

Hiromitsu Kuroda

Hideyuki Sagawa

Hidenori Abe

Takahiko Hanada

An enameled flat wire includes a flat wire and an enamel coating. The difference in thickness of the enamel coating on flat surfaces between a maximum thickness and a minimum thickness is equal to or less than 25% of the predetermined thickness. The enamel coating prior to baking includes a maximum surface curvature on each of the rounded corners of the wire, and a depression on at least one of the flat surfaces of the wire, the depression has a maximum surface curvature. The maximum surface curvature of the depression is larger than the maximum surface curvature of the enamel coating prior to baking on at least one of the rounded corners thereof.

Enameled flat wire

An audio/video cable includes an insulated layer including a copper conductor for transmitting audio/video signals and an insulation layer formed on a periphery thereof. The copper conductor includes a soft dilute copper alloy material containing pure copper, Ti as an additive element and an inevitable impurity as a balance. The soft dilute copper alloy material includes a recrystallized structure having a grain size distribution such that crystal grains in a surface layer are smaller than internal crystal grains. The soft dilute copper alloy material includes not less than 2 and not more than 12 mass ppm of sulfur, more than 2 mass ppm but not more than 30 mass ppm of oxygen, and not less than 4 and not more than 55 mass ppm of Ti.

Audio/Video cable

A weldment includes metal materials that are welded to each other. At least one of the metal materials includes pure copper including an inevitable impurity, more than 2 mass ppm of oxygen, and an additive element selected from the group consisting of Mg, Zr, Nb, Fe, Si, Al, Ca, V, Ni, Mn, Ti and Cr. A method of manufacturing a weldment includes melting a dilute copper alloy material by SCR continuous casting and rolling at a molten copper temperature of not less than 1100&#xb0; C. and not more than 1320&#xb0; C. to make a molten metal, forming a cast bar from the molten metal, forming a dilute copper alloy member by hot-rolling the cast bar, and welding the dilute copper alloy member to a metal material. The dilute copper alloy material includes the pure copper, more than 2 mass ppm of oxygen, and the additive element,?

Weldment

A manufacturing method uses a solid coating die for applying an insulation varnish around a flat wire conductor. The die includes a die body and a die hole formed through the die body, into which the conductor is inserted. The die hole includes an entry portion having a cross section monotonically decreasing along a conductor insertion direction, and a coating portion including at least a sub-portion having a constant cross section. The cross section of the coating portion is a rectangle having four straight sides and four rounded corners. Each inner surface of each straight side has an inwardly projecting protrusion, a top contour of each protrusion being a circular arc, an elongated circular arc, an elliptical arc or a combination of these arcs, the maximum curvature of the top contour of each protrusion being larger than the maximum curvature of inner surface of the rounded corners.

Manufacturing method of enameled flat wire using die for flat wire coating

An audio/video cable includes a plurality of parallel arranged insulated wires or twisted pair insulated wires each including a copper conductor and an insulation layer formed on a periphery thereof. The copper conductor includes a soft dilute copper alloy material containing pure copper, an additive element and an inevitable impurity as a balance. The soft dilute copper alloy material includes a recrystallized structure having a grain size distribution such that crystal grains in a surface layer are smaller than internal crystal grains. The surface layer includes a crystal structure such that an average crystal grain size from a surface of the surface layer up to a depth of 50 &#x3bc;m toward inside of the soft dilute copper alloy material is not more than 20 &#x3bc;m.

Audio/video cable

There is provided a coating die for applying an insulation varnish around a wire conductor, comprising: a die body; and a die hole formed through the die body, the die hole including: an entry portion having an opening size monotonically decreasing along a conductor insertion direction; and a coating portion comprising a sub-portion having a constant opening size, in which: on an inner surface of the coating portion are provided at least four protrusions equally spaced in a circumferential direction of the inner surface, the protrusions projecting toward a center axis of the die hole; and each of the protrusions includes a portion with a height gradually increasing along the conductor insertion direction from a boundary between the entry portion and the coating portion. There can be formed an enameled wire having a thin and uniform insulation coating by using the invented coating die.

Coating die and manufacturing method of enameled wire using same

A solid coating die for applying an insulation varnish around a flat wire conductor includes a die body and a die hole formed through the die body, the conductor to be inserted into the die hole. The die hole includes: an entry portion having a cross section monotonically decreasing along a conductor insertion direction; and a coating portion including at least a sub-portion having a constant cross section. The cross section of the coating portion is a rectangle having four straight sides and four rounded corners. Each inner surface of the straight side of the coating portion has an inwardly projecting protrusion, a top contour of each protrusion being a circular arc, an elongated circular arc, an elliptical arc or a combination of these arcs, the maximum curvature of the top contour of each protrusion being larger than the maximum curvature of inner surface of the rounded corners.

Die for flat wire coating and manufacturing method of enameled flat wire

A first varnishsupplied from a first varnish tankand a second varnishsupplied from a second varnish tankare mixed by a mixerto provide a varnish, and supplied to a varnish bath. Coating diesA-F are connected to the varnish bathvia tubesA-F. A wireis installed into the coating diesA-F through a holeprovided in each of the tubesA-F. The varnishsupplied to the varnish bathis dropped by its self weight through the tubesA-F, and continuously supplied to the coating diesA-F. The varnishis applied to a surface of the wireby the coating diesA-F.

Growing community of inventors

Hitachi, Japan

Masayoshi Goto