Wheel set structure of an electric wheelchair

A wheel set structure of an electric wheelchair, comprising:

• a wheelchair frame, said wheelchair frame defining a first direction of movement and a second direction of movement reversed from said first direction;
• at least one swinging mechanism pivotally mounted on said wheelchair frame, each said swinging mechanism comprising a swinging member and a wheel holder;
• at least one transmission wheel assembly connected to said swinging member, each said transmission wheel assembly comprising a motor and a driving wheel coupled to and rotatable by said motor;
• and
• at least one first wheel assembly mounted on said wheel holder, each said first wheel assembly pivotally holding a wheel;
• wherein when said at least one swinging member is biased relative to said at least one wheelchair frame, said at least one first wheel assembly is biased with said at least one swinging member so that the elevation of the wheel of each said first wheel assembly and the elevation of the driving wheel of each said transmission wheel assembly are relatively changed at a constant ratio;
• wherein the wheel holder of each said swinging mechanism is pivotally mounted on said wheelchair frame in such a manner that the axis of the pivot connection between the wheel holder of each said swinging mechanism and said wheelchair frame is same as the axis of the pivot connection between the swinging member of each said swinging mechanism and said wheelchair frame;
• wherein each said swinging mechanism further comprises a rigid link, said rigid link having two distal ends respectively connected to said at least one first wheel assembly and the swinging member of the respective swinging mechanism.