Patent ID: 8789455

Claim:
Positive displacement machine for transmitting energy to, or obtaining energy from, a working gas, said machine comprising: at least two pistons ( 22 ) spaced around a rotor ( 21 ) and rigidly attached thereto, each piston ( 22 ) being of the double-acting type and extending along an arc of circumference centered on an axis, called axis z ( 1 ) hereafter, said rotor ( 21 ) being mounted into a stator in such a way that it is able to oscillate about said axis z ( 1 ), and an assembly forming said stator, which delimitates the cylinder walls either by itself or together with the rotor ( 21 ), each cylinder ( 35 ) having intake ( 40 A) and discharge ( 40 B) means; said machine being characterized by a drive mechanism which transforms the rotating motion of a drive shaft ( 14 ) into the oscillatory motion of the rotor ( 21 ) or vice versa, said mechanism comprising: a ring gear ( 5 R) having a non-circular pitch curve with rotational symmetry of order m with respect to axis z ( 1 ), m being an integer greater than two, and being fixed to the rotor ( 21 ) and centered on axis z ( 1 ); a ring gear ( 5 S) having a non-circular pitch curve with rotational symmetry of order m with respect to axis z ( 1 ) and being fixed to the stator and centered on axis z ( 1 ); a first set of n like planet gears which are conjugate to the ring gear ( 5 R) fixed to the rotor, n being equal to m or a submultiple of m greater than one, with each planet gear ( 10 R) of said first set being in mesh with said ring gear fixed to the rotor ( 5 R) in such a way that said set has rotational symmetry of order n with respect to axis z ( 1 ); a second set of n like planet gears which are conjugate to the ring gear ( 5 S) fixed to the stator, with each planet gear ( 10 S) of said second set being in mesh with said ring gear ( 5 S) fixed to the stator in such a way that: said second set has rotational symmetry of order n with respect to axis z ( 1 ); each planet gear ( 10 S) of said second set has an axis w ( 2 ) in common with a planet gear ( 10 R) of the first set; and any two coaxial planet gears ( 10 R, 10 S) rotate conjointly and are angularly offset by the largest angle possible between any two maximum radii of respective said two planet gears; at least one planet carrier ( 12 ) whereto each pair of said coaxial planet gears ( 10 R, 10 S) is connected in such a way that said pair is rotatable about its axis w ( 2 ), which axis w ( 2 ) is in turn fixed relative to said planet carrier ( 12 ); a drive shaft ( 14 ) attached coaxially to said planet carrier ( 12 ) for rotation therewith.