Patent ID: 8684342
Filing Date: 2014-04-01
Classification: F16F,F16H

Abstract:
1. A coil spring comprising: a spring wire wound in a coil shape having an outer diameter side portion and an inner diameter side portion on a peripheral shape in a cross section thereof, the outer diameter side portion formed in a semi-circular shape expressed by x the coil shape of the spring wire is set to have an arc shape along an axis line of the coil spring in a free state; contact faces provided on both sides of the spring wire along the axis line of the coil spring, each contact face being provided between the inner diameter side portion and the outer diameter side portion on the peripheral shape in the cross section and being configured so as to extend from a region of the non-circular shape to a region of the semi-circular shape such that each contact face comes into contact with a contact face of an adjacent coil in the axial direction of the coil spring, in which “T” is a maximum thickness of the spring wire in the axial direction of the coil spring, “W” is a maximum width of the spring wire in a diametral direction of the coil spring, and “H” is a width of each contact face of the spring wire in the diametral direction of the coil spring so that a size of the width “H” is determined by the relative value of an oblateness T/W and the value of “α” when set in the range of 1.85 to 2.45; and each contact face having a width at the region of the non-circular shape in the diametral direction of the coil spring that is larger than a width of said each contact face at the region of the semi-circular shape in the diametral direction of the coil spring, said diametral direction extending in the direction along which the diameter of the coil spring is measured when said coil spring is viewed in cross section and wherein said respective widths of said regions at said respective non-circular and semi-circular shapes in the diametral direction of the coil spring are measured relative to said reference line that passes axially through the center of the non-circular and semi-circular shapes whereby said reference line is parallel to said axis line of the coil spring.