Two-layer coil structure
AssigneeAsahi Intecc Co., Ltd.
InventorTakaya Hashimoto
Life of this patent
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Abstract
A torque coil (two-layer coil structure) of the disclosed embodiments includes an inner coil formed by spirally winding metal wire, and an outer coil arranged to be in close contact with the outer periphery of the inner coil and formed by spirally winding metal wire. A winding direction of the inner coil and a winding direction of the outer coil are opposite from each other, and when the torque coil is twisted in the circumferential direction in which the diameter of the inner coil is increased, a change amount of the diameter of the outer coil is larger than a change amount of the diameter of the inner coil. The two-layer coil structure has high twisting rigidity, thus suppressing the occurrence of kinks due to rotational resistance.
Claims4
A two-layer coil structure, comprising:
- an inner coil that is formed by spirally winding metal wires;
- and
- an outer coil that is arranged to be in close contact with an outer periphery of the inner coil and formed by spirally winding metal wires, wherein
- a winding direction of the inner coil and a winding direction of the outer coil are opposite from each other,
- a material forming each of the inner coil and the outer coil is stainless steel of SUS304 or SUS316,
- a wire diameter of the metal wires forming each of the inner coil and the outer coil is in a range of 0.03 mm to 0.11 mm,
- an outer diameter of the inner coil is in a range of 0.3 mm to 0.5 mm,
- an inner diameter of the inner coil is in a range of 0.2 mm to 0.4 mm,
- an outer diameter of the inner coil is in a range of 0.4 mm to 0.6 mm,
- an inner diameter of the inner coil is in a range of 0.3 mm to 0.5 mm,
- each of the inner coil and the outer coil is formed by spirally winding 8 to 16 metal wires, and
- a number of the metal wires forming the outer coil is larger than a number of the metal wires forming the inner coil,
- wherein the two-layer coil structure is configured such that:
- (i) when the two-layer coil structure is twisted in a circumferential direction in which a diameter of the inner coil is increased, a change amount of the diameter of the inner coil is smaller than a change amount of a diameter of the outer coil, and
- (ii) in a test sample in which the inner coil and outer coil each have a length of 1596 mm, and d1 is the change amount of the diameter of the inner coil when the inner coil of the test sample is twisted by 360° in the circumferential direction in which the diameter of the inner coil is increased, and d2 is the change amount of the diameter of the outer coil when the outer coil of the test sample is twisted by 360° in the circumferential direction in which the diameter of the outer coil is decreased, the values of d1 and d2 satisfy the relation of −4.5<d2/d1<−1.6.
Dependencies are inferred from the claim text.