Pump

A fluid pump comprising the combination of a housing and a rotatable drive shaft journalled in the housing and defining a drive axis, a plurality of cylindrical pump chambers grouped around the drive axis along a circular path within a plane perpendicular to the drive axis with the axes of the chambers being generally parallel to the drive axis, a piston reciprocably received in each chamber for reciprocation along the axis of its associated chamber, swash plate means carried by the drive shaft for rotation therewith, an integral piston rod for each piston, means for rigidly connecting one end of each piston rod to its associated piston so as to extend in unguided, cantilever fashion therefrom toward and to the swash plate means, complementary ball joint means connecting each piston rod at the opposite end thereof to the swash plate means for oscillating such opposite end of each piston rod along a fixed arcuate drive path in a plane containing the drive axis as the drive shaft is rotated so that each such opposite end of the piston rod describes a fixed arcuate driving path which is different from linear reciprocation of its associated piston parallel to the drive axis so that the entire unguided portion of the piston rod from its rigid connection at the one end of the piston rod toward and to the swash plate means is free to oscillate cyclically in a plane perpendicular to the drive axis, and compensating means for compensating such cyclic oscillation of the unguided portion of each piston rod, each piston being formed of hard material of sleeve-like form, one end of each piston being supported in the housing and projecting therefrom and there being further housing support intermediate the ends of each piston.

A fluid pump comprising the combination of a hollow housing having opposite ends, one of the ends being closed to define a drive sump and a manifold assembly closing the other end of the housing, a rotatable drive shaft extending into the housing through the one end thereof and terminating adjacent the other end of the housing and journalled in the housing to define a drive axis, a plurality of cylindrical pump chambers grouped around the drive axis along a circular path within a plane perpendicular to the drive axis, each chamber being of sleeve-like form and having an end positioned beyond the drive shaft and covered at the other end of the housing by the manifold assembly, a piston reciprocably received in each chamber for reciprocation along the axis of its associated chamber, swash plate means within the sump and carried by the drive shaft for rotation therewith, an integral piston rod for each piston, means for rigidly connecting one end of each piston rod to its associated piston so as to extend in unguided, cantilever fashion therefrom toward and to the swash plate means, complementary ball joint means connecting each piston rod at the opposite end thereof to the swash plate means for oscillating such opposite end of each piston rod along a fixed arcuate drive path in a plane containing the drive axis as the drive shaft is rotated so that each such opposite end of the piston rod follows the fixed arcuate drive path which is different from linear reciprocation of its associated piston parallel to the drive axis so that the unguided portion of the piston rod cyclically oscillates in a plane perpendicular to the drive axis, and compensating means for compensating such cyclic oscillation of the unguided portion of each piston rod.