Run-flat device

A run-flat device, comprising:

• a plurality of support units arranged around a rotation axis in an annular shape, wherein two opposite directions along the rotation axis are respectively defined as a first direction and a second direction;
• each of the plurality of support units has a main wall, wherein a side of each of the plurality of main walls away from the rotation axis is connected to a hook portion;
• each of the plurality of hook portions extends in the first direction and has a free end;
• each of the plurality of hook portions has a retaining ring groove adjacent to each of the plurality of free ends;
• the side of each of the plurality of main walls away from the rotation axis is connected to an outer wall;
• a side of each of the plurality of main walls adjacent to the rotation axis is connected to an inner wall;
• each of the plurality of main walls is connected to a middle wall located between the side of each of the plurality of main walls away from the rotation axis and the side of each of the plurality of main walls adjacent to the rotation axis;
• each of the plurality of outer walls, each of the plurality of inner walls, and each of the plurality of middle walls respectively extend in the second direction;
• a blocking wall is connected between each of the plurality of outer walls and each of the plurality of inner walls;
• a support surface is formed on each of the plurality of main walls and each of the plurality of outer walls;
• a steel cable through hole is formed among each of the plurality of main walls, each of the plurality of inner walls, each of the plurality of middle walls, and each of the plurality of blocking walls;
• an elastic ring through hole is formed among each of the plurality of main walls, each of the plurality of outer walls, each of the plurality of middle walls, and each of the plurality of blocking walls;
• an inlet is formed on each of the plurality of blocking walls corresponding to each of the plurality of elastic ring through holes;
• a length of each of the plurality of inlets perpendicular to the rotation axis is less than a length of each of the plurality of elastic ring through holes perpendicular to the rotation axis;
• a retaining ring fixing the plurality of support units around the rotation axis in the annular shape;
• the retaining ring is an elastomer and tightly fits in the plurality of retaining ring grooves of the plurality of support units;
• a steel cable ring fixing the plurality of support units around the rotation axis in the annular shape;
• the steel cable ring passes through the plurality of steel cable through holes of the plurality of support units;
• an elastic ring fixing the plurality of support units around the rotation axis in the annular shape;
• the elastic ring passes through the plurality of elastic ring through holes of the plurality of support units and fits in the plurality of elastic ring through holes of the plurality of support units;
• the elastic ring is an elastomer;
• the elastic ring passes through the plurality of inlets of the plurality of support units after the elastic ring is compressed by an external force to be deformed.