The accelerator pedal, the reverse pedal, and the maximum machine speed potentiometer control the displacement of the front and rear power train pumps.
The speed selector switch controls the displacement of the travel motors.
The four wheel harvesters have two speeds. The six wheel harvesters have three speeds.
Speed Control (Pump)
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| Illustration 1 | g00469074 |
Schematic of the Power Train Pump (1) Proportional solenoid valve. (2) Pump displacement controls. (3) Lever. (4) Control spool. (5) Servo piston. (6) Proportional solenoid valve. (7) Actuator piston. (8) IQAN monitoring and control system. (9) Accelerator pedal. (10) Actuator piston. (11) Speed potentiometer. (12) Swashplate. (13) Reverse pedal. | |
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| Illustration 2 | g00570867 |
(8) IQAN monitoring and control system. (9) Accelerator pedal. (11) Speed potentiometer. (13) Reverse pedal. (14) Speed selector switch. | |
Accelerator pedal (9), speed potentiometer (11), and reverse pedal (13) control the current to the solenoids on the front and rear power train pumps.
When the current to solenoid (1) or the current to solenoid (6) increases, the oil flow from the pump increases. Thus, the machine is allowed to travel faster when the current to either solenoid on the pump is increased.
Pump displacement control (2) is used to control the direction of oil flow and the amount of oil flow from the pump.
During the forward operation, an electrical current is sent to proportional solenoid valve (1).
This allows charge oil to the top end of servo piston (5). Then, servo piston (5) moves downward. This causes lever (3) to pivot in a counterclockwise motion. This causes control spool (4) to move upward and this allows charge oil to flow to a set of actuator pistons (10).
Actuator pistons (10) move swashplate (12) counterclockwise. This produces oil flow from the pump.
During the reverse operation, an electrical current signals proportional solenoid valve (6). This allows the charge oil to flow to the bottom end of servo piston (5).
Then, servo piston (5) moves upward. This causes lever (3) to move in a clockwise motion. This causes control spool (4) to move down. Then, charge oil will flow to the other set of actuator pistons (7).
Actuator pistons (7) move swashplate (12) clockwise. This produces oil flow from the pump but in the opposite direction.
The pressure sensor senses the pressure in the loop and the pressure sensor sends the appropriate signal to pump displacement control (2). Pump displacement control (2) then strokes the pump when the pressure of the pump oil gets to the desired pump pressure.
Speed Control (Travel Motor)
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| Illustration 3 | g00685614 |
Speed Control System Schematic (8) IQAN monitoring and control system. (14) Speed selector switch. (15) Speed control valve. (16) Differential control valve. (17) Front travel motor. (18) Rear travel motor. (A) Port for charge pump oil. | |
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| Illustration 4 | g00570935 |
(15) Speed control valve. (16) Differential control valve. (19) Hydraulic oil tank. | |
Speed selector switch (14) controls the current to the solenoid of speed control valve (15). When the solenoid of speed control valve (15) is activated, oil from the charge pump flows to the travel motors. This oil is used to act against the displacement spool of the travel motors.
The displacement spool dictates the speed of the travel motors and the displacement of travel motors.
The travel motors have two speeds which are high speed and low speed.
Reference: For a detailed schematic of the power train system for your machine, refer to Wheel Harvester Power Train Schematic, RENR3020.
The following Tables show the speed and the displacement of each travel motor in different gear speeds.
The front travel motors and the rear travel motors on the four wheel harvesters are dual displacement motors.
| 550 and 570 Wheel Harvesters | ||||
| Gear Speed |
Speed of Travel Motor | Displacement of Travel Motor | ||
| Front | Rear | Front | Rear | |
| First Speed | Low | Low | High | High |
| Second Speed | High | High | Low | Low |
The front travel motors on the six wheel harvesters are fixed displacement motors. The rear travel motors are dual displacement motors.
| 580 Wheel Harvesters | ||||
| Gear Speed |
Speed of Travel Motor | Displacement of Travel Motor | ||
| Front | Rear | Front | Rear | |
| First Speed | Low | Low | High | High |
| Second Speed (1) | Freewheel (2) | High | Freewheel (2) | Low |
| Third Speed (3) | Freewheel (2) | High | Freewheel (2) | Low |
| ( 1 ) | The rear power train pump is running at 82%. |
| ( 2 ) | Oil from the front power train pump is blocked to the front travel motors. The front travel motors are also neutralized with charge pump oil. This allows the front travel motors to freewheel. |
| ( 3 ) | The rear power train pump is running at 100%. |