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| Illustration 1 | g00391917 |
Left Feed Roller Motor (1) Left feed roller motor. (2) Pressure line. (3) Pressure line. (4) Drain line. | |
The feed roller motors are radial piston motors. Hydraulic oil flows from the main control valve to the feed roller motors through hydraulic hose assemblies (2) and (3). When hydraulic hose assembly (2) is pressurized, the feed roller motor turns in the reverse direction. When hydraulic hose assembly (3) is pressurized, the feed roller motor turns in the forward direction. Case drain oil returns through hydraulic hose assembly (4) 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.
| Electrical Actuation of Valve Sections | |||
| Voltage | 6 V to 10.5 V | 12 ± 1.5 V (1) | 13.5 V to 18 V |
| Function | Position | ||
| Feed Roller Motors | REVERSE FEED | NEUTRAL | FORWARD FEED |
| ( 1 ) | The deadband is ± 1.5 volts. |
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| Illustration 2 | g00757951 |
The schematic of the feed roller motors is shown. (The spool is in the NEUTRAL Position.) (1) Left feed roller motor. (5) Right feed roller motor. (6) Crossover relief valves. (7) Main control valve. (8) Proportional solenoid. (9) Valve spool. (10) Pressure reducing valve (back pressure). (11) Flow compensator valve. (12) Resolver. (C) Drain line. (AA) Pressure tap (back pressure). | |
Note: Both feed roller motors operate the same way. The operation of the left feed roller motor is explained.
NEUTRAL Position
When the feed rollers are not being used, proportional solenoid (8) receives a 12 volt pulse width modulated signal from the computer aided bucking system. Valve spool (9) remains in the NEUTRAL position. No oil will flow to the feed roller motors or from the feed roller motors.
Crossover relief valves (6) protect the feed roller motors and hydraulic hose assemblies from damage when valve spool (9) 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 crossover relief valves (6), 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.
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| Illustration 3 | g00758163 |
Location of the Pressure Reducing Valve (Back Pressure) (7) Main control valve. (10) Pressure reducing valve (back pressure). (AA) Pressure tap. | |
Pressurized oil flows to pressure reducing valve (10) from the inlet section of main control valve (7). Oil flows from port (P1) to ports (P2) on the main control valve. The oil then flows to the feed roller motors. The flow of oil forces the pistons against the cam in the motor. This prevents damage to the pistons and the cam when the motor starts and when the motor stops. The oil flow prevents the pistons from slamming into the cam.
Pressure tap (AA) is available to measure the pressure of the oil that flows from pressure reducing valve (10) .
FORWARD FEED Position
When solenoid (8) receives a 13.5 to 18 volt signal, the feed roller motors turn in the forward direction. As the width of the signal to solenoid (8) increases, valve spool (9) moves further in the DOWN position.
Hydraulic oil flows through flow compensator valve (11) 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 valve spool (9). The oil flows to the feed roller motors. The oil then returns to the main control valve. Hydraulic oil also flows to flow compensator valve (11) and to resolver (12). The hydraulic oil passes through the resolver. The oil causes a signal pressure in line (LS) .
REVERSE FEED Position
When solenoid (8) receives a 6 to 10.5 volt signal, the feed roller motors turn in the reverse direction. As the width of the signal to solenoid (10) decreases, valve spool (9) moves further into the UP position.
Hydraulic oil flows through flow compensator valve (11) 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 valve spool (9). The oil flows to the feed roller motors. The oil then returns to the main control valve. Hydraulic oil also flows to flow compensator valve (11) and to resolver (12). The hydraulic oil passes through the resolver. The oil causes a signal pressure in line (LS) .