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| Illustration 1 | g01470877 |
Main control valve (felling head) (1) Inlet section (2) Boom control valve (3) Stick control valve (4) Tilt control valve (5) Swing control valve (6) Control valve (grapple arms) (7) Control valve (tool) (8) Control valve (accumulator arms) (9) End section | |
The track feller bunchers come in three types of arrangements: the felling head, the harvester head and the intermittent saw
Felling Head Arrangement
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| Illustration 2 | g01470893 |
Main control valve (1) Inlet section (2) Boom control valve (3) Stick control valve (4) Tilt control valve (5) Swing control valve (6) Control valve (grapple arms) (7) Control valve (tool) (8) Control valve (accumulator arms) (9) End section | |
The main control valve is a load sensing bank valve. The main control valve consists of the seven control valves. The control valves are the boom, the stick, the tilt, the swing, the grapple arms, the tool, and the accumulator arms.
All of the control valves are controlled by proportional solenoid valves. The proportional solenoid valves are activated by the joystick controls inside the cab. All of the control valves are actuated by pilot oil. When the operator moves a function, the pilot oil controls the movement of the closed center valve spools. The valve spools are spring centered.
All of the control valves have line relief valves except the swing control valve. The swing control valve has anticavitation valves. The line relief valves are located on the swing motor.
The following control valves have signal limiter valves:
- Tilt
- Swing
- Grapple arms
- Accumulator arms
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| Illustration 3 | g01371236 |
Top view of the main control valve (7 Bank) (10) Air purge valves (11) Line relief valves (12) Signal limiter valves (13) Proportional solenoid (Tilt LEFT) (14) Proportional solenoid (Tilt RIGHT) (P1) Inlet from pump (B1) Boom DOWN (B2) STICK IN (B3) Tilt LEFT (B4) Swing LEFT (B5) Grapple arms OPEN (B6) Tool DOWN (B7) Accumulator arms OPEN (A1) Boom UP (A2) Stick OUT (A3) Tilt RIGHT (A4) Swing RIGHT (A5) Grapple arms CLOSE (A6) Tool UP (A7) Accumulator arms CLOSE (T1) Return to hydraulic tank | |
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| Illustration 4 | g01371258 |
View A-A (P1) Inlet port from the main pumps (T1) Outlet port to the hydraulic tank (PL) Signal port to the travel valve (PS) Pilot port to the proportional solenoids | |
Pressure oil from the main pumps flows into the main control valve through port (P1) to the inlet section of the main control valve.
The pressure oil from the main pumps flows to the signal duplication valve, to the pressure differential relief valve and to all of the control valves.
As the function moves, the pressure oil and the flow that is required from the main pumps changes. A series of ball resolver valves direct the highest work port pressure to the main pumps. The required pressure is sensed in the load sensing system.
If air enters the pilot hydraulic system, the spools may not move smoothly. The air can be removed from the system, when the engine is running, through air purge valves (10).
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| Illustration 5 | g01501966 |
View B-B (P2) Inlet port from the main pumps (T3) Port to the hydraulic tank (TP) Port to the hydraulic tank | |
Pressure oil from the main pumps flows into the main control valve through port (P2) .
Return oil that bypasses the oil cooler flows from the main control valve through port (T3) back to the hydraulic tank. Return pilot oil flows from the main control valve through port (TP) to the travel control valve.
The following explanation is for the tilt function of the main control valve. The other sections of the main control valve operate similarly. The pressure settings of the line relief valves and the signal limiter valves are different for the other sections of the main control valve. The line relief valves are not adjustable. The control valve spools are actuated by pilot oil from the pilot hydraulic system.
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| Illustration 6 | g01165043 |
Partial Schematic of the Main Control Valve (Tilt Section) (11) Signal limiter valves (12) Line relief valves (13) Proportional solenoid (14) Proportional solenoid (15) Orifices (16) Signal duplication valve (17) End section (18) Inlet section (19) Main relief valve (20) Pressure compensator valve (21) Orifice (22) Spool (23) Tilt control valve (24) Resolver | |
When a circuit is deactivated the pressure on the load sensing relief valve in the travel control valve decreases. When the function is not activated, there is no load sensing pressure that is sent to the main pumps. The load sensing relief valve is opened by the pressure oil from the main pumps. The load sensing relief valve is adjustable.
Note: Signal duplication valve (16) regulates the load sensing pressure at port (PL) .
Main relief valve (19) is adjusted by the load sensing relief valve that is in the travel control valve. The pressure setting of the main relief valve is set at 35500 ± 500 kPa (5150 ± 75 psi). When the load sensing pressure in the main control valve exceeds the pressure setting of the load sensing relief valve, the load sensing relief valve opens. Pressure oil flows to the hydraulic oil tank.
This pressure setting for the main relief valve is effective with the following machines:
- 1390(B3F1-2309)
- 1490(B4F1-1999)
- 1490T(B5F1-1999)
The pump of the Track Feller Bunchers are now split. One is for the implement circuit and another one is for the travel circuit. The pressure setting for the main relief valve is set at 35500 ± 300 kPa (5150 ± 44 psi) for the implement valve. The pressure setting for the main relief valve is set at 36200 ± 300 kPa (5250 ± 44 psi) for the travel valve.
This pressure setting for the main relief valve is effective with the following machines:
- 1390(B3F2310-UP)
- 1490(B4F2000-UP)
- 1490T(B5F2000-UP)
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| Illustration 7 | g01501995 |
Section C-C (10) Air purge valves (11) Signal limiter valves (12) Line relief valves (20) Pressure compensator valve (21) Orifice (22) Spool | |
HOLD Position
When the trigger switch for the tilt function is not activated, valve spool (22) is in the HOLD position. Pressure compensator valve (20) contains a load hold check valve. The check valve prevents the tilt cylinders from moving. No oil will flow to the cylinders or from the cylinders.
Line relief valves (12) protect the tilt cylinders and hydraulic oil lines from damage. When an external load acts on the machine, the oil pressure in the circuit increases. When the pressure in the circuit exceeds the relief valve pressure setting, the line relief valve opens. The oil in the circuit returns to the hydraulic oil tank. The check valves in the line relief valves prevent cavitation in the cylinders.
The signal pressure oil drains from pressure compensator valve (20). The signal pressure strokes the main pumps to standby pressure.
Tilt LEFT
When the operator presses the switch on the joystick for tilt cylinder LEFT, a signal is sent to the IQAN controller. The IQAN controller sends current to proportional solenoid (13). The pilot oil flows through proportional solenoid (13) and orifice (15) to valve spool (22). Orifice (15) prevents the valve spool from moving rapidly. The valve spool shifts.
The pressure oil from the main pumps flows through pressure compensator valve (20). The oil flows to the head end of the tilt cylinder. Regardless of the main pump pressure, the pressure compensator valve maintains constant oil flow to the tilt cylinder.
Line relief valves (12) prevent cavitation. The check valve lifts up in order to allow oil from the return passage to flow into the hydraulic oil line and the tilt cylinder.
Pressure oil also flows into the circuit for the signal pressure. Signal limiter valves (11) limit the pressure in the signal circuit. The pressure setting of the signal limiter valve controls the maximum pressure signal to the main pumps. The pressure setting is adjustable.
Tilt RIGHT
When the operator presses the switch on the joystick for tilt cylinder RIGHT, a signal is sent to the IQAN controller. The IQAN controller sends current to proportional solenoid (14). The pilot oil flows through proportional solenoid (14) and orifice (15) to valve spool (22). Orifice (15) prevents the valve spool from moving rapidly. The valve spool shifts.
The pressure oil from the main pumps flows through pressure compensator valve (20). The oil flows to the rod end of the tilt cylinder. Regardless of the main pump pressure, pressure compensator valve (20) maintains constant oil flow to the tilt cylinder.
Line relief valves (12) prevent cavitation. The check valve lifts up in order to allow oil from the return passage to flow into the hydraulic oil line and the tilt cylinder.
Pressure oil also flows into the circuit for the signal pressure. Signal limiter valves (11) limit the pressure in the signal circuit. The pressure setting of the signal limiter valve controls the signal to the main pumps. The pressure setting is adjustable.
Signal pressure oil also flows to the pressure compensator valve. Orifice (21) limits the response of the pressure compensator to the load signal. Resolver (24) directs the highest signal pressure to the inlet section of the main control valve.
The load sensing signal pressure flows to signal duplication valve (16). The signal duplication valve shifts allowing the load sensing signal pressure to flow through the travel valve to the main pumps. The load sensing signal pressure upstrokes the main pumps.