Universal wheel

A universal wheel, comprising:

• a support base, the support base including a top portion connected with a steering assembly that enables 360° rotation of the universal wheel;
• a rolling assembly, the rolling assembly including an axle and a roller rotatably connected to the axle, a coordinate system being constructed with a center of the roller as an origin, a traveling direction of the roller as a negative direction of an abscissa, and a direction perpendicular to the abscissa and extending upward as a positive direction of an ordinate, the support base having a chute located in a first quadrant, and the axle being slidably connected to the chute along a radial direction of the roller;
• and
• a shock-absorbing assembly, the shock-absorbing assembly including a damped stretchable element having a lower end connected to the axle and an upper end connected to the support base, a component force of a force applied by the stretchable element on the axle, which is applied to the axle along a moving direction of the axle, being defined as a first component force, a component force of a maximum bearable load force of the axle, which is applied to the axle along the moving direction of the axle, being defined as a second component force, and the first component force being greater than the second component force to force the axle to always be located at a bottom end of the chute without an external force;
• wherein the stretchable element is a spring, a gas spring or a hydraulic rod;
• wherein the support base includes a fixed plate connected to an upper end of the stretchable element;
• wherein when the stretchable element is a spring, the fixed plate has a through hole in which a support rod is slidably connected, a lower end of the support rod is fixedly connected to the axle, and the spring is fitted onto the support rod and located between the axle and the fixed plate.