| 摘要 |
The multiple pump apparatus includes first and second variable displacement closed circuit pumps. The multiple pump apparatus pressurizes fluid to be subsequently supplied to drive load devices. The first and second pumps each have fluid communication lines connected to load devices through flow control valves. Each of the pumps has a swashplate for varying its displacement. The swashplates are of the over-center type, enabling each pump to supply pressurized fluid in either direction, thus providing both forward and reverse function to the load devices. The first pump has its fluid communicating lines connected to fluid communicating lines between first and second two-position four-way flow control valves. The opposite side of the first flow control valve has fluid communicating lines connected to a load device which drives a harvesting mechanism, in this case a rotor motor. The opposite side of the second flow control valve has communication lines connected to the circuit for driving the load device for the propel function, in this case, the propel motor(s). In this way, the combined flow from the two pumps enables the vehicle to attain high speed operation for roading without the need for a single large fluid displacement propel pump to support this performance requirement.
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