The feed roller motors are radial piston motors. Hydraulic oil flows from the main control valve to the feed roller motors through the hydraulic hose assemblies. When one of the hydraulic hose assemblies is pressurized, the feed roller motor turns in the reverse direction. When the hydraulic hose assembly is pressurized, the feed roller motor turns in the forward direction. Case drain oil returns through the hydraulic oil return to the hydraulic oil tank on the machine.
The speed of the feed roller motors is controlled by the flow of oil to the motors from proportional solenoid valves. The computer allows the following speeds for the feed roller motors: crawl speed, low speed and high speed. The computer aided bucking system controls the flow of oil to the feed roller motors by controlling the movement of the proportional solenoid valves. The computer aided bucking system controls the movement of the proportional solenoid valves with a pulse width modulated signal. The maximum speed of the feed roller motors is manually set with the stroke limiter screws on the pilot housing of the main control valve.
Note: Both feed roller motors operate the same way. The operation of the left feed roller motor is explained.
When the feed rollers are not being used, the proportional solenoid will receive no signal from the computer aided bucking system. The valve spool remains in the NEUTRAL position. No oil will flow to the feed roller motors or from the feed roller motors.
The crossover relief valves protect the feed roller motors and hydraulic hose assemblies from damage when The valve spool is in the NEUTRAL position. When an external load acts on the feed roller motors, the oil pressure in one side of the circuit increases. When the pressure in the circuit exceeds the pressure setting of the crossover relief valves, the crossover relief valve opens. The oil in the pressurized circuit flows to the opposite side of the feed roller motor. The hydraulic oil recirculates as the external force turns the feed roller motor.
No pressurized oil flows when in the NEUTRAL position.
The pressure tap is available to measure the pressure of the oil that flows from the pressure reducing valve.
The computer controls the two pilot solenoid valves. The valves in turn control the flow to the feed motors. The pilot valves are proportional valves controlled by the valve spool.
Hydraulic oil flows through the pressure reducing valve to the main control valve. The flow compensator valve limits the maximum flow of the oil to the main control valve. The hydraulic oil passes through the valve spool. The oil flows to the feed roller motors. The oil then returns to the main control valve. The oil causes a signal pressure in the "LS" line.
The computer controls the two pilot solenoid valves. The valves in turn control the flow to the feed motors. The pilot valves are proportional valves controlled by the valve spool.
Hydraulic oil flows through the pressure reducing valve to the main control valve. The pressure reducing valve limits the maximum flow of the oil to the main control valve. The hydraulic oil passes through the valve spool. The oil flows to the feed roller motors. The oil then returns to the main control valve. The oil causes a signal pressure in "LS" line.