Patent ID: 8393602
Filing Date: 2013-03-12
Classification: F16F,F16H

Abstract:
1. A spring comprising: a coil spring having an irregular cross section, the coil spring being made by subjecting a coil wire having an irregular cross section to a fatigue-strength improving treatment including a shot peening treatment after coiling the coil wire into a spring configuration of a polar coordinate system having a pole, and a polar axis extending from the pole toward a coil central axis in a coil radial direction, and having a vertical cross-sectional profile taken along in a coil axial direction of said coil wire, the vertical cross-sectional profile forming a substantially ellipse shape in which not only said pole has the central axis but also said coil radial direction has a major-diameter direction; and labeling a major-diameter-side maximum diameter of said vertical cross-sectional profile “2LR”, labeling a minor-diameter-side maximum diameter of said vertical cross-sectional profile “2SR”, labeling a central offset coefficient in said major-diameter direction “Δb,” and additionally labeling an inner-side x-axis coefficient “nxr” and labeling an inner-side y-axis coefficient “nyr” in an orthogonal coordinate system in which said pole makes an origin and said polar axis being set in a positive area of an x-axis, said vertical cross-sectional profile having a coil inner-peripheral-side section expressed by following Equation (1) and Equation (2): wherein θ is a deflection angle in said polar coordinate system, and 0°≦θ<90°, 270°≦360°, 0.7≦nxr≦0.9, 0.8≦nyr≦1.0, and 0.1SR≦Δb≦0.3SR, in said Equation (1) and Equation (2).