摘要 |
A multi-function valve usable in a hydrostatic transmission and having valve components mounted in a single valve body to provide pressure limiter and high pressure relief functions and with the structure also providing a bypass function and for supply of makeup fluid to the hydrostatic transmission. The multifunction valve has a charge check valve member and a relief valve member in associated relation and movable upon the occurrence of a predetermined pressure differential thereacross to perform control functions. One pressure differential results from a flow through an orifice and with the flow being controlled by a poppet valve member normally held closed by a heavy spring which establishes a system pressure at which the pressure limiter function will occur. With this structure, the pressure limiter function occurs in advance of the high pressure relief function and under the control of a single heavy spring. With two of the multi-function valves utilized with the hydrosratic transmission, various controls are operable with flow in either direction to the motor through pressure lines between the pump and motor defining a closed loop circuit.
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