A method of modeling and designing a helical spring, the helical spring including a top end turn (1), a top transition turn (2), an active turn (3), a bottom transition turn (4), and a bottom end turn (5) from top to bottom, the method including: utilizing first interpolation to determine the radius (R3) of the active turn (3), wherein the active turn (3) is as a function of the longitudinal overall length (L) of the helical spring; and utilizing second interpolation to determine the radius (R2) and the z-coordinate position (Z2) of the top transition turn (2) and the radius (R2) and the z-coordinate position (Z2) of the bottom transition turn (4), wherein each of the z-coordinate position (Z3(?, L)) of the active turn (3), the radius (R2) and the z-coordinate position (Z2) of the top transition turn (2) and the radius (R2), and the z-coordinate position (Z2) of the bottom transition turn (4) is as a function of the longitudinal overall length (L) and the twist angle (?) of the helical spring.

A coil spring for a vehicle suspension according to one embodiment includes a lower end turn portion, an upper end turn portion, and a cylindrical effective portion between the lower end turn portion and the upper end turn portion. In at least one of the upper end turn portion and the lower end turn portion, a taper portion having a taper length and a taper thickness for controlling a force line of the coil spring is formed. The taper portion is formed such that the thickness is reduced in a tapered way from a thickness varying portion provided in the middle of the end turn portion toward a distal end of the wire along its length. The thickness varying portion is arranged at a position close to the force line.

A coil spring for use in a link-motion-type suspension includes a lower end turn portion, an upper end turn portion, and an effective portion of a cylindrical shape between the lower end turn portion and the upper end turn portion. Further, the coil spring includes a bowing control portion including a taper portion formed in at least one end turn portion of the lower end turn portion and the upper end turn portion. The taper portion has a shape whose thickness is reduced from the middle of the end turn portion toward a distal end of a wire along its length, and bowing of the effective portion is suppressed by absorbing a change in the inclination of a spring seat by the taper portion.

A coil spring according to one embodiment includes a lower end turn portion which is in contact with a lower spring seat, an upper end turn portion which is in contact with an upper spring seat, and an effective portion between the lower end turn portion and the upper end turn portion. The coil spring is cylindrical about an axis of the effective portion in its free shape which is not compressed. Further, with respect to a coordinate system in which a force line is assumed as a Z-axis, the coil spring is cylindrical with a constant pitch in a direction along the Z-axis in its compressed shape which is compressed to a specified height.

A coil spring includes a wire formed of spring steel shaped to be helical, and is compressed between an upper spring seat and a lower spring seat. The coil spring includes an upper portion and a lower portion. A positive pitch winding end portion is formed on the upper portion of the coil spring. A terminal-point-strong-abutting-portion is formed at a distal end of the winding end portion. The terminal-point-strong-abutting-portion is in contact with the upper spring seat at one point at a position deviated to an inner side of a vehicle with respect to a coil central axis. On the lower portion of the coil spring, an end turn portion which contacts the lower spring seat is formed at a position deviated to an outer side of the vehicle.

A coil spring for a vehicle suspension according to one embodiment includes a lower end turn portion, an upper end turn. portion, and a cylindrical effective portion between the lower end turn portion and the upper end turn portion. In at least one of the upper end turn portion and the lower end turn portion, a taper portion having a taper length and a taper thickness for controlling a force line of the coil spring is formed. The taper portion is formed such that the thickness is reduced in a tapered way from a thickness varying portion provided in the middle of the end turn portion toward a distal end of the wire along its length. The thickness varying portion is arranged at a position close to the force line.

An elastic member is an elastic member formed of a wire having a cross section that is substantially circular, the cross section being orthogonal to a longitudinal direction, and the elastic member being expandable and contractible in a predetermined direction; and including: a first alloy portion that is made of an aluminum alloy having a tensile strength larger than 950 MPa and equal to or less than 1100 MPa at room temperature; and a second alloy portion configured to cover the first alloy portion, the second alloy portion having a thickness in a radial direction smaller than a radius of the first alloy portion, and being made of an aluminum alloy having a tensile strength of 100 MPa to 650 MPa at room temperature.

A strut-type suspension includes a compression coil spring, a lower spring seat, an upper spring seat, and a shock absorber. The compression coil spring is disposed at a position offset to the outer side of a vehicle with respect to the shock absorber. The compression coil spring is mounted in a vehicle body in such a state that it is compressed between spring seats. The compression coil spring includes a large-diameter wire portion and a small-diameter wire portion. The large-diameter wire portion is provided in a vehicle inner-side portion of the compression coil spring. The small-diameter wire portion is provided in a vehicle outer-side portion. A wire diameter of the large-diameter wire portion is greater than a wire diameter of the small-diameter wire portion.

The present invention relates to a suspension strut for a motor vehicle with a vibration damper, with a supporting spring and with a height-adjustment device, with which the height of the vehicle body of the motor vehicle can be changed, and wherein the suspension strut has an auxiliary spring having a lower spring characteristic than the supporting spring, by means of which auxiliary spring a residual prestress can be produced in the supporting spring when the vibration damper is extended, and wherein the auxiliary spring is integrated in the height-adjustment device.

To provide a suspension coil spring capable of reducing a bowing amount and friction generated in a shock absorber, under a compressed state.

A suspension coil spring (10) that is mounted between an upper seat (22) and a lower seat (24) in a strut suspension (12) for an automobile, includes an upper end turn (32) that sits on the upper seat (22); a spring active portion (11) that includes one or more coils each of which is formed such that a portion whose curvature is the largest is positioned at an automobile outer side under a mounted state; and a lower end turn (34) that sits on the lower seat (24) while substantially contacting the lower seat (24) at a single lower contacting point (P3) that is positioned at the automobile outer side with respect to a center point of the lower end turn (34).