Multiple pivot crank device with combined type crank pin structure crankshaft

The invention relates to a multi-support point crank mechanism, a crankshaft of which is a combined crank pin structure, and belongs to the mechanical transmission technical field. The mechanism comprises a mechanism body. The mechanism body is equipped with at least three siamesed supports escaping the position of connecting rod, and the siamesed supports are equipped with concentric through-holes. Each through-hole supports a coaxial rotating crankshaft section respectively. Opposite ends of two neighboring crankshaft sections are equipped with corresponding eccentric structures respectively. The eccentric structures support two end sections of a crank pin. An external circle of the crank pin inserts in an internal hole at one end of the connecting rod. A revolute pair is formed at either between the eccentric structure and the crank pin, or between the crank pin and the external circle. The prominent advantage of the invention is that the rigidity and intensity are greatly increased, which is favorable for bearing a big bending moment; manufacture of parts is quite simple; the thermal processing quality can be easily controlled; the invention is easy for installation and disassembly; a rolling bearing is allowed in the position of the revolute pair so as to promote the transmission performance of the crank mechanism.