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| Illustration 1 | g03715510 |
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(1A) Accumulator (high pressure)
(1B) Accumulator (low pressure) (2) Cushion-Hitch Leveling Valve (3) Cushion-Hitch Ride Dampening Valve (4) Hydraulic Tank (5) Apron Cylinder (6) Implement Control Valve (7) Bowl Cylinders (8) Ejector Cylinder (9) Implement Pump (10) Cushion-Hitch Pump (11) Oil filter (Cushion-Hitch and pilot pressure) (12) Load Cylinder (13) Pilot Manifold (14) Joystick Control (15) Implement ECM (16) Push-Pull Control Valve (If equipped) (17) Bail Cylinder (If equipped) | |
The implement hydraulic system is a load sensing system that consists of a pilot hydraulic system and a main hydraulic system. The pilot system controls the functions of the main control valve. The pilot hydraulic system is controlled by the implement electronic control system.
The main hydraulic system consists of implement pump (9), implement control valve (6), and the implement cylinders. The 631K Wheel Tractor-Scrapers are equipped with apron cylinder (5), two bowl cylinders (7), and ejector cylinder (8).
Implement pump (9) is a piston type pump. Implement pump (9) is installed on the transfer gear case housing. The pump supplies oil to implement control valve (6).
The pilot hydraulic system consists of cushion-hitch pump (10). Cushion hitch pump (10) provides the pilot oil supply for the shuttle valves, the pressure reducing valve, and pilot actuator valves.
The pilot solenoid valve directs oil from cushion-hitch pump (10) to the pilot control valves of the implement control valve. The pressure reducing valve reduces the pressure of oil from the cushion-hitch pump to pilot pressure.
Implement control valve (6) contains three valve spools. The three valve spools direct implement pump oil to ejector cylinder (8), bowl cylinders (7), and apron cylinder (5). Implement control valve (6) is electronically controlled by the joystick control (14) in the cab. When the implement control lever is moved from the HOLD position, an electrical signal is sent from Implement ECM (15) to a pilot control valve solenoid. The solenoids activate the pilot control valves which direct pilot oil in order to shift the valve spools in implement control valve (6).
In the HOLD position, both solenoids for the pilot control valves are de-energized. When both solenoids are de-energized, the pilot spools direct pilot oil to the ends of the main spool. The pilot pressure at each end of the main spool, and the force of the centering springs cause the main spool to be centered in the control valve. The centering springs and retainers help stabilize the movement of the main spool. The stabilizing springs dampen the movement of the pilot spools by holding the pilot spools in contact with the feedback springs.
When implement control valve (6) is in the HOLD position, pump oil flows through implement control valve (6) and through a return line filter. The return line filter is located in hydraulic tank (4). The return line filter has a bypass valve. The oil will flow through the inlet passage. The oil will then flow through the filter element before the oil flows to hydraulic tank (4). The filter element removes debris from the oil before the oil flows to hydraulic tank (4). When the filter element becomes blocked, flow of oil will be restricted. Restriction of oil flow causes an increase in pressure on the outside of the filter element. High oil pressure opens the bypass valve. The bypass valve will allow unfiltered oil to pass to hydraulic tank (4).
The Implement hydraulic system is controlled by the implement ECM (15). The ECM responds to operator control inputs. When the operator commands hydraulic attachments to move, the ECM activates the appropriate pilot solenoid valves. The valves allow oil to flow to the corresponding main control valves. The main control valves control the various cylinders and hydraulic attachments. The operator joystick has detents that are activated by the ECM.
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| Illustration 2 | g03715512 |
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(1A) Accumulator (high pressure)
(1B) Accumulator (low pressure) (2) Cushion-Hitch Leveling Valve (3) Cushion-Hitch Ride Dampening Valve (4) Hydraulic Tank (5) Apron Cylinder (6) Implement Control Valve (7) Bowl Cylinders (8) Ejector Cylinder (9) Implement Pump (10) Cushion-Hitch Pump (11) Oil filter (Cushion-Hitch and pilot pressure) (12) Load Cylinder (13) Pilot Manifold (14) Joystick Control (15) Implement ECM (16) Push-Pull Control Valve (If equipped) (17) Bail Cylinder (If equipped) | |
The implement hydraulic system is a load sensing system that consists of a pilot hydraulic system and a main hydraulic system. The pilot system controls the functions of the main control valve. The pilot hydraulic system is controlled by the implement electronic control system.
The main hydraulic system consists of implement pump (9), implement control valve (6), and the implement cylinders. The 637K Wheel Tractor-Scrapers are equipped with apron cylinder (5), two bowl cylinders (7), and ejector cylinder (8).
Implement pump (9) is a piston type pump. Implement pump (9) is installed on the transfer gear case housing. The pump supplies oil to implement control valve (6).
The pilot hydraulic system consists of cushion-hitch pump (10). Cushion hitch pump (10) provides the pilot oil supply for the shuttle valves, the pressure reducing valve, and pilot actuator valves.
The pilot solenoid valve directs oil from cushion-hitch pump (10) to the pilot control valves of the implement control valve. The pressure reducing valve reduces the pressure of oil from the cushion-hitch pump to pilot pressure.
Implement control valve (6) contains three valve spools. The three valve spools direct implement pump oil to ejector cylinder (8), bowl cylinders (7), and apron cylinder (5). Implement control valve (6) is electronically controlled by the joystick control (14) in the cab. When the implement control lever is moved from the HOLD position, an electrical signal is sent from Implement ECM (15) to a pilot control valve solenoid. The solenoids activate the pilot control valves which direct pilot oil in order to shift the valve spools in implement control valve (6).
In the HOLD position, both solenoids for the pilot control valves are de-energized. When both solenoids are de-energized, the pilot spools direct pilot oil to the ends of the main spool. The pilot pressure at each end of the main spool, and the force of the centering springs cause the main spool to be centered in the control valve. The centering springs and retainers help stabilize the movement of the main spool. The stabilizing springs dampen the movement of the pilot spools by holding the pilot spools in contact with the feedback springs.
When implement control valve (6) is in the HOLD position, pump oil flows through implement control valve (6) and through a return line filter. The return line filter is located in hydraulic tank (4). The return line filter has a bypass valve. The oil will flow through the inlet passage. The oil will then flow through the filter element before the oil flows to hydraulic tank (4). The filter element removes debris from the oil before the oil flows to hydraulic tank (4). When the filter element becomes blocked, flow of oil will be restricted. Restriction of oil flow causes an increase in pressure on the outside of the filter element. High oil pressure opens the bypass valve. The bypass valve will allow unfiltered oil to pass to hydraulic tank (4).
The Implement hydraulic system is controlled by the implement ECM (15). The ECM responds to operator control inputs. When the operator commands hydraulic attachments to move, the ECM activates the appropriate pilot solenoid valves. The valves allow oil to flow to the corresponding main control valves. The main control valves control the various cylinders and hydraulic attachments. The operator joystick has detents that are activated by the ECM.