Insulated wire, coil, and electrical or electronic equipment
View Patent ↗An insulated wire including: a conductor; and an insulating film provided on an outer periphery of the conductor, wherein the insulating film satisfies the following relation between a relative permittivity (ε) of the insulating film at 0.2 atm and a relative permittivity (ε 0 ) of an outermost layer of the insulating film at 0.2 atm. ε≤3.0 and ε 0 /ε≥1.2.
1. An insulated wire, comprising:
a conductor; and
an insulating film provided on an outer periphery of the conductor, wherein the insulating film satisfies the following relation at 0.2 atm between a relative permittivity (ε) of the insulating film and a relative permittivity (ε 0 ) of an outermost layer of insulating layers constituting the insulating film:
ε≤2.4 and ε 0 /ε≥1.2.
wherein the insulating film satisfies the following relation between a thickness (T) of the insulating film and a thickness (T 0 ) of the outermost layer of the insulating film:
0< T 0 /T≤ 0.1 and T≥ 30 μm,
wherein each of the insulating layers constituting the insulating film is made of a resin material containing polyimide or polyamide imide, and
wherein the insulating film has two or three layers.
2. The insulated wire according to claim 1 , wherein at least one of the insulating layers constituting the insulating film is a bubble-containing layer.
3. The insulated wire according to claim 2 , wherein a porosity of the bubble-containing layer is 5 to 70 vol %.
4. The insulated wire according to claim 2 , wherein the bubble-containing layer is an enamel layer formed by baking a thermosetting resin.
5. The insulated wire according to claim 1 , wherein the outermost layer of the insulating film contains an inorganic microparticle.
6. The insulated wire according to claim 5 , wherein the inorganic microparticle contains titanium dioxide.
7. A coil, comprising the insulated wire according to claim 1 .
8. An electrical or electronic equipment, comprising the coil according to claim 7 .