Combine harvester rotor speed control and control method

A combine harvester comprising a frame supported and propelled by wheels;

• a crop gathering mechanism mounted on a forward portion of the frame for conveying crop material to a separator housing;
• a threshing and separating rotor rotatably journaled on the frame inside the separator housing;
• a concave mounted on the frame that cooperates with the rotor to thresh grain;
• a cleaning assembly mounted on the frame inside the separator housing;
• an internal combustion engine mounted on the frame for driving the harvester;
• a rotor hydraulic pump mounted on the frame and driven by the internal combustion engine;
• a hydraulic motor, driven by the rotor hydraulic pump, mounted on the frame and connected to the rotor;
• a pump displacement control mounted on the rotor hydraulic pump;
• a rotor speed sensor mounted on the frame that sensing the speed of rotation of the threshing and separating rotor;
• a rotor speed selector mounted on the frame adjacent to an operator's work station;
• an electronic controller mounted on the frame and connected to the rotor speed sensor, the rotor speed selector and the electronic pump displacement control and which compares actual rotor speed with selected rotor speed and adjusts the rotor hydraulic pump displacement to maintain actual cylinder speed within a selected rotor speed range.

A self-propelled combine harvester comprising a frame;

• a separator housing mounted on the frame;
• a crop gathering mechanism mounted on a forward portion of the frame for conveying crop material to the separator housing;
• a threshing and separating rotor rotatably journaled on the frame inside the separator housing;
• a concave mounted on the frame that cooperates with the rotor to thresh grain from crop material received from the crop gathering mechanism;
• a grain cleaning assembly mounted on the frame for cleaning grain received from the threshing and separating rotor;
• an internal combustion engine mounted on the frame for driving the harvester;
• a hydraulic pump driven by the internal combustion engine;
• a hydraulic motor, driven by the hydraulic pump, and connected to and driving the threshing and separating rotor;
• and
• a controller mounted on the frame and having a reverse mode that reverses the direction of rotation of the hydraulic motor and the threshing and separating rotor.

A method of controlling the speed of the threshing cylinder of a combine harvester that is driven by an internal combustion engine, a hydraulic pump and a hydraulic motor comprising;

• running the internal combustion engine at a speed controlled by an engine governor;
• selecting a desired threshing cylinder speed;
• measuring an actual threshing cylinder speed;
• comparing the actual threshing cylinder speed with the desired cylinder speed;
• and
• adjusting the output speed of the hydraulic motor when there is a significant variation between the actual threshing cylinder speed and the desired threshing cylinder speed.