Auxiliary pump for hydrostatic transmission

摘要

An auxiliary pump assembly for a hydrostatic transmission that operates at a reduced pressure when the auxiliary circuit is not in use, and operates at an increased pressure when the auxiliary circuit is in use, thereby reducing the heat generated by the auxiliary pump. The auxiliary pump assembly can be used to supply low pressure makeup flow to a closed loop of a hydrostatic transmission. A combination valve including a bypass valve and a relief valve is also provided.