A torsion spring assembly for a wheel suspension of a motor vehicle, including two torsion bars arranged coaxially one inside another and also a spring element, which is arranged axially-parallel to the two coaxial torsion bars, and can be mounted on the motor vehicle body via a bearing position, wherein the radial outer hollow-cylindrical torsion bar can be mounted on the motor vehicle body side and is connected in a rotationally-fixed manner to an output lever fastenable on a wheel guiding element and the radial inner torsion bar is connected in a rotationally-fixed manner to the outer torsion bar and is connected in a rotationally-fixed manner via a coupling to the spring element.

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.

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 trailer for towing by a power vehicle is provided and generally includes a frame and a tandem wheel assembly. The frame forms an undercarriage chassis and the tandem wheel assembly positioned under the undercarriage chassis. The tandem wheel assembly includes a rear wheel assembly and a front wheel assembly. An extension assembly is provided and moves the front wheel assembly between trailing position and a self-propelled position where the rear wheel assembly and the front wheel assembly are positioned to equally support the undercarriage chassis.

An axle cartridge member receives a pair of torsion stub axles at opposite lateral sides thereof. The torsion stub axles include elongated axle housings, which are sandwiched between two parallel plates to align the torsion stub axles with respect to one another. The cartridge member includes a central arch extending between the two torsion stub axles, which can provide additional ground clearance when the axle cartridge member is mounted to a trailer.

This torsion beam manufacturing method is a method of manufacturing a torsion beam that includes a uniformly shaped closed cross-sectional portion of which a cross section orthogonal to a longitudinal direction is a closed cross section having a substantial V-shape or a substantial U-shape at any position in the longitudinal direction, and a shape changing portion which has a connection region leading to the uniformly shaped closed cross-sectional portion and including a closed cross section having a shape different from the shape of the closed cross section of the uniformly shaped closed cross-sectional portion. The torsion beam manufacturing method includes pulling process of applying a tensile force in the longitudinal direction to at least the connection region of a torsion beam material including the uniformly shaped closed cross-sectional portion and the shape changing portion, to obtain the torsion beam.

A driver torque estimation device includes: a transfer ratio variation device and a torsion bar; an electric motor; a torque sensor; an input shaft rotation acquisition unit configured to acquire the rotational angle of an input shaft of the transfer ratio variation device; and an electronic control unit configured to acquire the rotational angle of an output shaft of the transfer ratio variation device. The electronic control unit is configured to compute an estimated value of first disturbance. The electronic control unit is configured to compute an estimated value of second disturbance. The electronic control unit is configured to compute an estimated value of driver torque based on the torsion bar torque, the estimated value of the first disturbance, and the estimated value of the second disturbance.

A driver torque estimation device includes: a transfer ratio variation device and a torsion bar; an electric motor; a torque sensor; an input shaft rotation acquisition unit configured to acquire the rotational angle of an input shaft of the transfer ratio variation device; and an electronic control unit configured to acquire the rotational angle of an output shaft of the transfer ratio variation device. The electronic control unit is configured to compute an estimated value of first disturbance. The electronic control unit is configured to compute an estimated value of second disturbance. The electronic control unit is configured to compute an estimated value of driver torque based on the torsion bar torque, the estimated value of the first disturbance, and the estimated value of the second disturbance.

A stabilizer includes a stabilizer main body, and eyes formed on both ends of the stabilizer main body. Through-holes are formed in fastening surfaces of the eyes, respectively. The stabilizer main body is covered with a main body coating film. The eye is covered with an eye coating film whose thickness is less than a thickness of the main body coating film. An inner surface of the through-hole is covered with an inner surface coating film. An incomplete coating portion is formed at a part of the inner surface of the through-hole in a circumferential direction. The incomplete coating portion is located on an extension of a straight line connecting a center of the through-hole and the center of gravity of the stabilizer main body in a side view of the stabilizer main body.

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.