Patent ID: 6082986
Filing Date: 2000-07-04
Classification: F01C

Abstract:
A reversible double-throw air motor, comprising a housing having a cavity defined by a peripheral wall and spaced-apart proximal and distal end walls;a tubular cylinder member mounted in the housing cavity for rotation between a forward position and a reverse position and having an inner surface defining a hole of uniform oblong cross section along its length and having a lengthwise center axis, the inner surface having first, second, third, and fourth quadrants defined by intersections with the inner surface of mutually perpendicular planes that include the center axis, one of which planes intersects the cylinder inner surface at diametrically opposite bottom dead center lines and the other of which planes intersects the cylinder inner surface at top dead center lines;a rotor mounted in the housing for rotation about the cylinder center axis and having a circular cylindrical body portion received within the cylinder hole, the peripheral surface of the body portion being in close running radial clearance with the inner surface of the cylinder member hole at the bottom dead center lines, and the peripheral surface of the rotor, surfaces of the cavity end walls, and the cylinder inner surface defining two rotating crescent-shaped chambers;a plurality of circumferentially spaced-apart vanes carried by the rotor body portion for radial displacement toward and away from the cylinder axis and engaging the cylinder inner surface and the cavity end walls such as to divide the two rotating crescent-shaped chambers into a plurality of variable volume rotating working subchambers;exhaust passages in the housing opening at a pair of diametrically opposite circumferentially elongated exhaust ports in the proximal end wall of the cavity, the exhaust ports being positioned and configured to open exclusively to portions of the two crescent-shaped chambers radially inwardly of the first and third quadrants of the cylinder inner surface when the cylinder member is in the forward position and to open exclusively to portions of the two crescent-shaped chambers radially inwardly of the second and fourth quadrants of the cylinder inner surface when the cylinder member is in the reverse position;pressure passages in the housing opening at a pair of diametrically opposite pressure ports in the proximal end wall of the cavity radially outwardly of the two crescent-shaped chambers in all rotational positions of the rotor and facing an end wall of the cylinder; andtwo diametrically opposite pairs of air transfer passages in the said tubular cylinder member, each transfer passage being associated with one of the quadrants of the cylinder inner surface, the transfer passages of each pair being closely adjacent to and symmetrically located with respect to one of the bottom dead center lines of the cylinder inner surface and having end ports opening at a proximal end surface of the cylinder, one of which end ports opens to a pressure port in the forward position of the cylinder and the other of which end ports opens to a pressure port in the reverse position of the cylinder, and each transfer passage opening at a wall port at the inner surface of the cylinder member in the quadrant of the cylinder inner surface with which the transfer passage is associated.