DRIVE DEVICE FOR THERMODYNAMIC RECIPROCATING ENGINE

PURPOSE:To simplify the structure of an engine and as well to make the engine compact and lightweight, by providing such an arrangement that piston members are reciprocated with a phase difference within a crank operating space which is maintained at a pressure lower than the lowest pressure in either one of high and low temperature working spaces. CONSTITUTION:A displacer 1 is coupled with a crank shaft 13 in such a way that the projection 19 of a displacer rod 11 is abutted against the cam surface 21 of an eccentric cam part 20 formed on the crank shaft 13, and a coming-off preventing wall part 22 prevents the above-mentioned projection 19 from coming off the cam surface 21. A crank chamber space 23 is maintained always at a pressure lower than the lowest pressure of a high temperature side working space 6 so that downward urging force is always exerted to a piston 2, and therefore, there is no need to provide a projection to a piston rod 24, and a coming-off preventing wall part to an eccentric cam part 25. Further, there is no need to use a connecting rod for driving the displacer 1 and the piston 2. Accordingly, the structure of the engine is simplified and as well the structure of the engine may be made compact and lightweight.