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| Illustration 1 | g01325142 |
Standard flow for the work tool hydraulic system (1) Auxiliary circuit (2) Auxiliary hydraulic connector (3) Coupler cylinder (quick coupler) (4) Control manifold (quick coupler) (5) Hydraulic oil tank (6) Gear pump (charge oil) (7) Gear pump (work tool) (8) Relief valve (charge oil) (9) Hydraulic accumulator (pilot) (10) Control manifold (pilot shutoff) (11) Return manifold (12) Control manifold and solenoid (if equipped) (13) Manual lowering valve for the lift arms (14) Control valve (work tool) (15) Lift cylinder (16) Tilt cylinder (17) Auxiliary hydraulic connector | |
The piston pump for the hydrostatic system is mounted to the engine. The two-section gear pump is mounted to the piston pump for the hydrostatic system. The gear pump for the work tools (7) is mounted to the piston pump for the hydrostatic system. The gear pump (work tool) (7) supplies the work tool hydraulic system with oil. When the engine speed increases, the speed of pump (7) increases. This increase causes the pump to move oil to the work tool hydraulic system. The control valve (work tool) (14) is an opened center control valve.
The pilot oil for the work tool hydraulic system is supplied by the gear pump (charge oil) (6). The gear pump (charge oil) (6) is splined to the drive shaft of the gear pump (work tool) (7). Oil flows out of the gear pump (charge oil) (6) to the fan drive motor. The oil flows through the fan drive motor to the oil filter. From the oil filter, the oil flows to the front section of the piston pump for the hydrostatic system. At the piston pump, the hydraulic oil flows passed the solenoid valve (parking brake). In order for the oil to flow to the control valve (work tool) (14), all three of the electronic interlocks must be disengaged. In order for oil to flow through the control manifold (pilot shutoff) (10), the hydraulic enable solenoid must be energized.
When the engine starts rotating, charge oil will supply the accumulator (9). The charge pump directs oil flow to the control manifold (pilot shutoff) (10). The oil flows downstream across a one-way flow check valve. The oil will flow directly to the accumulator (9). No electrical components need energized for oil to flow to the accumulator (9). The charge oil will also flow to the control manifold (pilot shutoff) (10). When the control manifold (pilot shutoff) (10) is activated, oil will be directed to the control valve (work tool) (14). The electrohydraulic control lever for the hydraulic work tool must be activated to a desired position in order to activate the solenoid valve. Once the solenoid valve is activated the charge oil shifts the control spool to the desired position. Once the control spool shifts, the high-pressure oil from the gear pump (work tool) (7) will flow to the selected work tool. Relief valve (8) maintains the pressure for the charge oil.
Hydraulic System with the Control Manifold and Solenoid (Work Tool Positioner)
When the electrohydraulic control lever for the work tool is moved to the RAISE position, the solenoid valve in the control valve is activated in order to shift the lift spool in the control valve (work tool) (14). Once the lift spool shifts to the RAISED position by pilot oil, hydraulic oil flows from the gear pump (work tool) (7). The oil flows through the lift spool and into the line for the head end of the lift cylinder (15). The oil from the rod end of the lift cylinder (15) flows to the Control Manifold and Solenoid (12). The pressure from the rod end of the lift cylinders (15) is balanced with the pressure from the head end of the tilt cylinders (16). This pressure causes the work tool to remain level while the lift arms are raised. From the Control Manifold and Solenoid (12), the oil flows to the lift spool. The oil then flows out of the control valve (14) and back to the tank (5) .
The Control Manifold and Solenoid (12) effects only the RAISE function. The LOWER function is not affected by the Control Manifold and Solenoid (12). In the LOWER position, oil flows from the spool to the Control Manifold and Solenoid (12). From the Control Manifold and Solenoid (12), the oil flows to the rod end of the tilt cylinder (16). The oil pushes the piston. The cylinders retract. Oil from the head end of the cylinders flows to the lift spool. The oil then flows out of the control valve (work tool) (14) and back to the hydraulic oil tank (5) .
For information on the operation of the Control Manifold and Solenoid (12), refer to the machine Systems Operation, KENR5113, "Control Manifold and Solenoid (Work Tool Positioner)".
The manual lowering valve (13) is used for manual lowering of the lift arms. The manual lowering valve allows oil to drain out of the head end of the lift cylinder (15). The hydraulic oil flow is directed to the return manifold (11). The manual lowering valve should be used to lower the lift arms when the engine fails.
Hydraulic System Without the Control Manifold and Solenoid (Work Tool Positioner)
When the control lever for the work tool is moved to the RAISE position, the solenoid valve is activated. The solenoid valve allows pilot oil to flow to the left side of the lift spool that is part of the control valve (work tool) (14). The pilot oil causes the lift spool to shift to the right.
Hydraulic oil flows from the gear pump (work tool) (7) into the control valve (work tool) (14). The oil then flows past the lift spool and into the line for the head end of the lift cylinder (15) .
As oil forces the rods of the lift cylinder to extend, oil is forced out of the rod end of the cylinders. The oil that flows from the rod ends of the cylinders flows to the lift spool. The oil then flows out of the control valve (work tool) (14) and back to the hydraulic oil tank (5) .
When the control lever for the work tool is moved to the LOWER position, the pilot oil flows to the right side of the lift spool in the control valve (work tool) (14). The pilot oil causes the lift spool to shift to the left. Hydraulic oil flows from the gear pump (work tool) (7) through the spool and into the line for the rod end of the lift cylinders.
As oil forces the rods to retract, the oil is forced out of the head end of the cylinders. The oil flows to the lift spool. The oil then flows out of the control valve (work tool) (14) and back to the hydraulic oil tank (5) .
The FLOAT position allows the work tool to follow the contour of the ground. The FLOAT position can be activated by moving the joystick to the LOWER position and pressing and releasing the trigger.
Once the float function is engaged, the joystick can be returned to the NEUTRAL position without affecting the float function. FLOAT will remain engaged until the trigger on the right-hand joystick is pressed again. The float function will disengage also when the bucket is raised or when the bucket is lowered.
When the control lever for the work tool is moved to the FLOAT position, the solenoid valve is activated. The solenoid valve allows pilot oil to flow to the right side of the lift spool that is part of the control valve (work tool) (14). The pilot oil causes the lift spool to shift fully to the left. In this position, the spool opens the rod ends and head ends of both of the lift cylinders to the hydraulic oil tank (5). The weight of the work tool will cause the work tool to lower to the ground. The work tool will then follow the contour of the ground. Supply oil from the gear pump (work tool) (7) will continue to flow into the control valve (work tool) (14). The supply oil will not flow to the lift cylinder (15). The tilt spool may be operated when the lift spool is in the FLOAT position.
In the event of engine failure, the manual lowering valve (13) is used in order to lower the lift arms manually. The manual lowering valve (13) allows oil to drain out of the head end of the lift cylinders. The hydraulic oil flow is directed to the return manifold (11) .
Hydraulic System for the Tilt Cylinders
The hydraulic oil is directed to the tilt spool in the control valve (work tool) (14) by the solenoid valve. The end of the spool that receives the pilot oil depends on the position of the electrohydraulic control lever for the work tool.
As the spool shifts, hydraulic oil from gear pump (work tool) (7) flows through the tilt spool and into both of the tilt cylinder (16). Oil that leaves the tilt cylinders flows to the tilt spool. The oil then flows out of the control valve (work tool) (14) and back to the hydraulic oil tank (5) .
If equipped with a Control Manifold and Solenoid (12), the tilt cylinders will also be connected to the Control Manifold and Solenoid (12). The Control Manifold and Solenoid (12) acts as a load leveler. The Control Manifold and Solenoid (12) is used only when the lift cylinders are being raised.
For more information on the operation of the hydraulic system for the tilt cylinders, refer to the machine Systems Operation, KENR5113, "Control Valve (Work Tool)". For information on the operation of the Control Manifold and Solenoid (12), refer to the machine Systems Operation, KENR5113, "Control Manifold and Solenoid (Work Tool Positioner)".
Auxiliary Hydraulic System
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| Illustration 2 | g01333145 |
Typical right-hand joystick control with momentary push-button switches (18) Joystick control (19) Auxiliary hydraulic control (20) Auxiliary hydraulic control | |
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| Illustration 3 | g01374258 |
Typical right-hand joystick control with proportional thumb wheel switch (18) Joystick control (19) Auxiliary hydraulic control (20) Auxiliary hydraulic control | |
When you activate the auxiliary hydraulic control (19) or the auxiliary hydraulic control (20) that is located on the joystick control (18), pilot oil is directed to the auxiliary circuit spool that is located in the control valve (work tool) (14).
When the auxiliary hydraulic control (19) is activated, the Electronic Control Module (ECM) activates the auxiliary hydraulic solenoid. Pilot oil from the gear pump (charge oil) (6) moves through the energized solenoid in order to activate the auxiliary hydraulic spool. The pilot oil causes the auxiliary spool to shift to the left. Supply oil from the gear pump (work tool) (7) flows through the spool to the auxiliary hydraulic connector (2). Oil from the gear pump flows through the work tool circuit and back through the auxiliary hydraulic connector (17) to the spool for the auxiliary. The oil then flows out of the control valve (work tool) (14) and back to the hydraulic oil tank (5) .
When you activate the auxiliary hydraulic control (20), the ECM activates the auxiliary hydraulic solenoid. Pilot oil from the gear pump (charge oil) (6) moves through the energized solenoid in order to activate the auxiliary hydraulic spool. The pilot oil causes the auxiliary spool to shift to the left. Supply oil from the gear pump (work tool) (7) flows through the spool to the auxiliary hydraulic connector (17). Oil from the gear pump flows through the work tool circuit and back through the auxiliary hydraulic connector (2) to the spool for the auxiliary. The oil then flows out of the control valve (work tool) (14) and back to the hydraulic oil tank (5) .
For more information on the operation of the hydraulic system for the auxiliary, refer to the machine Systems Operation, KENR5113, "Control Valve (Work Tool)".