Abstract: A flow-control valve assembly for connection between a source of fluid under pressure and a fluid-operated load has a main valve and a pilot valve. The main valve defines a continuous flow path having an input end connectable to the source of fluid under pressure and an output end. This valve further has a valve member which defines with the housing of the main valve a plurality of variable flow restrictions, the valve member being displaceable in the main-valve housing between an open position wherein the restrictions are all of maximum flow cross section and a closed position wherein the restrictions are all of minimum flow cross section. A pilot valve has an input side connected to the output end of the continuous flow path through the main valve and an output side connectable to the load.

Abstract: A variable-output pump has an output-adjusting element which is acted upon by a differential piston arrangement having oppositely facing active surfaces of a smaller and of a larger active area. Control fluid is permanently admitted to the smaller active area of the differential piston arrangement to act on the same and urge the output-adjusting element of the pump toward a low-output position. A biasing spring acts against the force of the fluid acting on the smaller surface, and the control fluid is also selectively admitted to the larger surface to urge the adjusting element toward higher outputs. A control slide controls the admission of the control fluid to the larger surface of the differential piston arrangement and has a housing provided with a bore in which a slide is mounted for movement longitudinally of the bore. The slide has an end face acted upon by the control fluid and another end face acted upon by a spring.

Abstract: A fluid machine, particularly a hydraulic pump, has a high pressure side and a low pressure side. A rotor or a pair of cooperating gears are mounted for rotation and have spaced end faces extending transversely of their respective axes of rotation. Walls define at each of these end faces at least one fluid compartment which is open to the respective end face and which communicates via a restricted outflow gap with the low pressure side of the machine, and via a conduit with the high pressure side of the machine. In each conduit a throttle is interposed, and the end faces are subjected from the respective compartments to fluid pressures which permanently tend to equalize with one another, and which therefore tend to axially center the rotor or gears in the event of axial displacement thereof.