A body weight adjustment mechanism for automatic adjustment to a balanced point is provided to improve vibration absorption characteristics and impact absorption characteristics. A torsion angle of a lower frame-side torsion bar when an upper frame is at a balanced point is found in advance, a torsion angle of the lower frame-side torsion bar in a state in which a person is seated is detected, the detected torsion angle is compared with the aforesaid balanced point torsion angle, a control signal is sent to an elastic force adjusting unit, and torsion angles of upper frame-side torsion bars are adjusted so that the torsion angle of the lower frame-side torsion bar becomes equal to the balanced point torsion angle. The upper frame can be set to an appropriate position in an initial state and a static state in which a person is seated and vibration and impact absorption characteristics are improved.

A body weight adjustment mechanism for automatic adjustment to a balanced point is provided to improve vibration absorption characteristics and impact absorption characteristics. A torsion angle of a lower frame-side torsion bar when an upper frame is at a balanced point is found in advance, a torsion angle of the lower frame-side torsion bar in a state in which a person is seated is detected, the detected torsion angle is compared with the aforesaid balanced point torsion angle, a control signal is sent to an elastic force adjusting unit, and torsion angles of upper frame-side torsion bars are adjusted so that the torsion angle of the lower frame-side torsion bar becomes equal to the balanced point torsion angle. The upper frame can be set to an appropriate position in an initial state and a static state in which a person is seated and vibration and impact absorption characteristics are improved.

An aluminum alloy according to the present invention includes 1.2% by mass to 4.0% by mass of copper, 4.0% by mass to 14.0% by mass of zinc, 0.5% by mass to 4.0% by mass of magnesium, 0.01% or less of silicon, and 0.01% or less of iron, with the balance containing aluminum and inevitable impurities, and has an average equivalent circle crystal grain size of 500 nm or less.

A spring assembly comprises an edge wound wave spring and a shim. The spring comprises a plurality of axially spaced, axially compressible wave-like turns extending between a first end portion and a second end portion. The first end portion comprises a plurality of closely arranged parallel turns. The shim comprises a shim body and at least one mounting lug projecting radially from the shim body. The mounting lug is received between adjacent turns of the first end portion of the edge wound wave spring for retaining the shim to the edge wound wave spring.

A spring assembly comprises an edge wound wave spring and a shim. The spring comprises a plurality of axially spaced, axially compressible wave-like turns extending between a first end portion and a second end portion. The first end portion comprises a plurality of closely arranged parallel turns. The shim comprises a shim body and at least one mounting lug projecting radially from the shim body. The mounting lug is received between adjacent turns of the first end portion of the edge wound wave spring for retaining the shim to the edge wound wave spring.

Provided are a forming method for an arc spring, capable of easily and surely locating bearing faces on both end faces of a semi-finished product in predetermined positions, the bearing faces having lengths within permissible ranges in a circumferential direction. For a semi-finished product prior to curving an axis, it is determined whether circumferential lengths of bearing faces on both end faces are respectively within the permissible ranges based on end face image information of the both end faces imaged in an axial direction prior to the curving, a circumferential rotational position of the semi-finished product capable of respectively locating the bearing faces within the predetermined positions is specified using the end face image information, and the semi-finished product is rotated to the specified rotational position, and the wedge part is sequentially driven into inter-wires of the semi-finished product to deform the semi-finished product.

A coil spring of this invention includes a first end coil part with a first bearing surface facing to the first side in the axial direction, a second end coil part with a second bearing surface facing to the second side in the axial direction and a central coil part connecting the first and second end coil parts. A displacement length in the axial direction from the outer end portion until the inner end portion of the first end coil part is a thickness of a spring wire forming the coil spring so that a space between the outer end portion of the first end coil part and an inner end portion of the central coil part is zero, and a displacement length in the axial direction between the outer end portion of the first end coil part and a point away along the circumferential direction from the outer end portion toward the inner end portion of the first end coil part by a half of turn around the axial line is less than a half of the thickness of the spring wire.

A coil spring of this invention includes a first end coil part with a first bearing surface facing to the first side in the axial direction, a second end coil part with a second bearing surface facing to the second side in the axial direction and a central coil part connecting the first and second end coil parts. A displacement length in the axial direction from the outer end portion until the inner end portion of the first end coil part is a thickness of a spring wire forming the coil spring so that a space between the outer end portion of the first end coil part and an inner end portion of the central coil part is zero, and a displacement length in the axial direction between the outer end portion of the first end coil part and a point away along the circumferential direction from the outer end portion toward the inner end portion of the first end coil part by a half of turn around the axial line is less than a half of the thickness of the spring wire.

Wave springs having multiple variable turns, methods of pre-loading components with said wave springs, and methods of manufacturing said wave springs are provided. The wave spring has a total height defined by a first end portion and a second opposite end portion and an intermediate portion disposed between the first and second end portions. The intermediate portion has active turns with waved or non-planar turns and non-active turns with planar or non-waved turns. The wave spring also has a first alignment disposed between the first and second end portions, wherein first alignment comprises at least two waved or non-planar turns being aligned with each other.

Drive devices, in particular linear drives, spindle drives, and/or telescopic drives, for moveable vehicle components are provided. A housing assembly for a drive device is also provided. A connecting element for a drive device is also provided. A spring element for a drive device is also provided.