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 rotary cutter having a torsional suspension system may include a main frame, a deck supported by the frame, at least one rotary cutter mounted to the deck, at least one wheel, and a torsional suspension system connecting the at least one wheel to the frame. The torsional suspension system may include an outer tubular housing, an inner torsional tube disposed in the outer housing and configured to form cavities between the outer housing and the inner torsional tube, and elastomeric cords disposed in the cavities and configured for providing torsional resistance to rotation of the outer housing relative to the inner torsional tube.

An independent suspension comprises upper and lower fork arms, elastic elements, shock absorber and fork arm positioning pivots. The fork arms are A-shaped, front ends of the fork arms respectively connect to upper and lower suspension points of a wheel, and rear ends of the fork arms connect to a vehicle frame through the elastic elements. The shock absorber mounts on top of the front end of the upper fork arm. Vehicle frame bearing pivot points and transmission parts are constructed on peripheries of the upper and lower fork arms. The arrangement absorbs bearing elastic forces by changing directions of force and the arms of force, to form multiple points supporting multiple elastic elements, so force applied on the wheel is distributed by multiple points, increasing average running speed. Increasing the number and arrangement of the elastic elements reduces vehicle height, optimizes space utilization and improves stability and running smoothness.

The twist axle assembly includes a pair of spaced apart trailing arms and a twist beam of which extends in a first direction between the trailing arms. The twist beam includes a pair of end portions and a middle portion. The twist beam further has a pair of side walls and at least one additional wall that extends between the side walls. The side walls in the middle portion are generally parallel with the side walls of the end portions. The twist beam is generally hour-glass shaped with the middle portion having a first width and the end portions have a greater second width. The twist beam also tapers from the first width of the middle portion to the second widths of the end portions for gradually increasing a torsional stiffness from the middle portion to the end portions.

The present invention relates to a suspension arrangement for a tracked vehicle. The suspension arrangement includes a road wheel arm having a wheel axle portion for supporting a wheel of the vehicle and a pivot axle portion. The road wheel arm is pivotably journalled at the pivot axle portion to a housing that is fixable to the vehicle body. A torsion bar is connected to the pivot axle portion and a torsion tube is arranged to be connected to the vehicle body, with the torsion bar running through the torsion tube and arranged to be connected to the torsion tube. The modulus of elasticity of the torsion tube material is lower than the modulus of elasticity of the torsion bar material such that the maximum suspension travel is increased.

Disclosed herein is a rear subframe and suspension system. The subframe may be configured to accommodate one or two electric motors for propelling an automobile. The subframe may be configured such that the motor(s) is inserted through the front end of the subframe. The subframe may substantially surround the motor. Braces may be the coupled to the subframe to secure the motor within the subframe. The subframe may further include built-in motor mounts. An independent rear suspension system and rear steering system may also be coupled to the subframe.

A mobile robot configured to drive on a surface with irregularities, comprising: a chassis having a front end facing a forward direction of travel, a back end, a first side, and a second side. There is a first drive wheel rigidly affixed to the chassis proximate the first side and interconnected to a motor to propel it. There is a second drive wheel rigidly affixed to the chassis proximate the second side and interconnected to a motor to propel it. A first caster assembly is rigidly affixed to the chassis proximate the front end and includes a first caster wheel configured to rotate about a first swivel axis. A second caster assembly is rigidly affixed to the chassis proximate the back end and includes a second caster wheel configured to rotate about a second swivel axis and it includes a compliant member to absorb the irregularities.

A mobile robot configured to drive on a surface with irregularities, comprising: a chassis having a front end facing a forward direction of travel, a back end, a first side, and a second side. There is a first drive wheel rigidly affixed to the chassis proximate the first side and interconnected to a motor to propel it. There is a second drive wheel rigidly affixed to the chassis proximate the second side and interconnected to a motor to propel it. A first caster assembly is rigidly affixed to the chassis proximate the front end and includes a first caster wheel configured to rotate about a first swivel axis. A second caster assembly is rigidly affixed to the chassis proximate the back end and includes a second caster wheel configured to rotate about a second swivel axis and it includes a compliant member to absorb the irregularities.

A wheel assembly includes a constant force mechanism and a wheel coupled to the constant force mechanism. The wheel is displaceable in at least one dimension, and the constant force mechanism imparts a substantially constant force on the wheel in the dimension. In one aspect, the wheel is displaceable in a first regime and a second regime. For a wheel displacement in the first regime, the constant force mechanism imparts a substantially constant force on the wheel, and for a wheel displacement in the second regime, the constant force mechanism imparts a variable force on the wheel. The variable force can be linear or non-linear to the magnitude of the displacement in the second regime and is equal to or greater than the substantially constant force.

The present invention provides a method for manufacturing a torsion beam, the method comprising: a planarization step, in which a protruding portion of an upper mold presses the opposite end portions in the width direction of the blank to be plastically deformed to be flat while the opposite end portions in the width direction of the blank are supported by a side cam to face each other; a welding and bonding step for bonding the planarized opposite end portions in the width direction of the blank via welding; and a quenching step for heating the welded and bonded blank within a range of 900 to 970? C. for a retaining time within a range of 1 to 20 minutes and for cooling down the blank in a treatment liquid including at least one of water and oil in a range of 20 to 90? C.