초록 ▼

A hydraulic drive apparatus for example for driving the header of a combine harvester includes a pump, at least one motor driven by the pump, a reservoir in which the hydraulic fluid is cooled and degasified and a hydraulic circuit connecting the elements. The pump is driven by a shaft of the combin

A hydraulic drive apparatus for example for driving the header of a combine harvester includes a pump, at least one motor driven by the pump, a reservoir in which the hydraulic fluid is cooled and degasified and a hydraulic circuit connecting the elements. The pump is driven by a shaft of the combine which can be reversed for short periods of time for discharging blockages. The hydraulic circuit is arranged with check valves so that when operating in the normal forward condition it operates in open circuit arrangement including the reservoir. When operating in the reverse condition, the reservoir is bypassed and the fluid is directed in closed circuit condition from the pump through the motor and back to the pump. This allows the drive apparatus to accommodate the necessary reverse condition for short periods of time using a simple hydraulic circuitry rather than the conventional mechanical drive arrangements.

대표청구항 ▼

[ I claim:] [1.] A hydraulic drive apparatus comprising:a hydraulic pump connected to an input drive member by which the pump is driven to generate pressure in a hydraulic fluid, the pump having a first port and a second port;a direction of drive of the drive member being reversible so that a direct

[ I claim:] [1.] A hydraulic drive apparatus comprising:a hydraulic pump connected to an input drive member by which the pump is driven to generate pressure in a hydraulic fluid, the pump having a first port and a second port;a direction of drive of the drive member being reversible so that a direction of drive of the pump is reversible between a forward direction to intake fluid into the first port and expel pressurized fluid at the second port and a reverse direction to take intake fluid into the second port and expel pressurized fluid at the first port;a motor driven by the pressurized fluid from the pump, the motor having a first port and a second port arranged such that supply of the pressurized fluid to the first port drives the motor in a forward direction and releases discharge fluid at the second port and such that supply of the pressurized fluid to the second port drives the motor in a reverse direction and releases discharge fluid at the first port;and a hydraulic circuit for connecting the pump and the motor, the hydraulic circuit comprising:a hydraulic fluid reservoir for receiving the discharge fluid from the motor and for supplying hydraulic intake fluid to the pump;a first hydraulic circuit portion including a first hydraulic line connecting fluid from the reservoir to the first port of the pump, a second hydraulic line connecting fluid between the second port of the pump and the first port of the motor, and a third hydraulic line connecting fluid from the second port of the motor to the reservoir;a second hydraulic circuit portion including a fourth hydraulic line connecting fluid to the second port of the motor from the first port of the pump, the fourth hydraulic line by-passing the reservoir;and valve means for controlling flow of fluid in the first and second hydraulic circuit portions, the valve means being operable in response to a change in the direction of drive of the pump such that, when the pump is driven in the forward direction, the hydraulic circuit causes the hydraulic fluid to pass through the first hydraulic circuit portion into and from the reservoir and, when the pump is driven in the reverse direction, the hydraulic circuit causes the hydraulic fluid to pass through the second hydraulic circuit portion by-passing the reservoir.