Patent ID: 8443713

Claim:
A rotary cylinder device, in which linear reciprocation of pistons in cylinders and rotation of a shaft can be interconverted, comprising: a first crank shaft being eccentrically connected to the shaft, the first crank shaft being rotated about the shaft by a first imaginary crank arm which has a radius (r); a piston composite body having an eccentric tube body constituted by a first tube body, which is concentrically fitted to the first crank shaft, and second tube bodies, which are extended from the first tube body and whose axes are second imaginary crank shafts eccentrically disposed with respect to the axis of the first tube body, the piston composite body being rotated about the first crank shaft, by a second imaginary crank arm which has a radius (r), in a state where piston assemblies are attached to the second tube bodies and intersected with each other; a first balance weight and a second balance weight being respectively attached to ends of the first crank shaft, to which the piston composite body is fitted, so as to produce a rotational balance between rotating parts around the shaft; a main body case rotatably holding the shaft and rotatably accommodating the first crank shaft, which is rotated about the shaft, the first and second balance weights and the piston composite body, which is rotated about the first crank shaft; and guide bearings guiding the linear reciprocation of the piston assemblies attached to the second tube bodies, which are caused by rotating the first crank shaft about the shaft and rotating the piston composite body about the first crank shaft, in the radial direction of a rolling circle of the second imaginary crank shafts, which has a radius (2r) and which is centered at the shaft, wherein the first crank shaft is rotated about the shaft and the piston composite body is rotated about the first crank shaft in a state where mass balances of a first rotational balance relating to the piston assemblies around the second imaginary crank shafts, a second rotational balance relating to the piston composite body around the first crank shaft and a third rotational balance relating to the first crank shaft and the piston composite body around the shaft are equally balanced by only the first and second balance weights which are attached to both ends of the first crank shaft, thereby the piston assemblies, which are attached to the second tube bodies, are relatively rotated about the shaft, and their linear reciprocation in the cylinders are guided by the guide bearings.