Patent ID: 6263670
Filing Date: 2001-07-24
Classification: F15B,F16D,F16H

Abstract:
A closed circuit hydrostatic transmission comprising:an open casing at least partially enclosing rotating elements of a hydraulic pump and rotating elements of a hydraulic motor;the hydraulic pump and motor being fluidly connected by first and second system pressure lines;a three position, three port pilot pressure operated loop flushing valve having a first inlet port fluidly connected to the first system pressure line, a second inlet port fluidly connected to the second system pressure line, and an outlet port fluidly connecting the loop flushing valve to a case opening in the open case through a drain line having a drain orifice therein; anda hydraulic loop flushing line fluidly connected to the drain line upstream of the drain orifice, the loop flushing line extending within the casing and having an open end generally adjacent to and directed toward the rotating elements of one of the pump and motor;the three position loop flushing valve having an intermediate position between two opposite end positions and wherein system pressure from at least one of the first and second system pressure lines is always routed to the loop flushing line through the valve regardless of which of the three positions the valve is in.