 | |
| Illustration 1 | g02038313 |
Control valve stack (1) Blade lift control valve (2) Blade tilt control valve (3) Ripper lift control valve (4) Return to tank (5) Main relief valve (HPRL) Hydraulic pilot pressure (ripper lower) (6) Ripper lower solenoid (HPTL) Hydraulic pilot pressure (tilt left) (7) Blade tilt left solenoid (HPDR) Hydraulic pilot pressure (dozer raise) (8) Blade raise solenoid (9) Inlet manifold (10) Inlet port from the pump (11) Blade lower solenoid (HPDL) Hydraulic pilot pressure (dozer lower) (12) Blade tilt right solenoid (HPTR) Hydraulic pilot pressure (tilt right) (13) Ripper raise solenoid (HPRR) Hydraulic pilot pressure (ripper raise) | |
The following four implement control valves may be mounted together in the valve stack:
- Blade lift control valve (1)
- Blade tilt control valve (2)
- Ripper lift control valve (3) (if equipped)
- Blade angle control valve (not pictured) (if equipped)
Inlet manifold (9) is mounted to blade lift control valve (1). The inlet manifold contains main relief valve (5) .
The implement control valves are activated by proportional solenoids. A solenoid is located at either end of each control valve. The solenoids control the pilot oil that shifts the valve spools. The solenoids are activated by electrical signals from the hydraulic ECM. The electrical signals are proportional to the direction and the amount of movement of the implement control levers.
Hydraulic implement oil flows from the pump to the pilot pressure reducing valve. The supply oil is reduced to pilot pressure. The oil then enters inlet manifold (9). The supply oil is available in parallel to each solenoid.
When the valve spools are in the HOLD position, the oil is blocked. When the valve spool shifts, oil is sent into the implement circuit.
Each control valve has a resolver valve. The resolvers work together in order to ensure that the highest pressure that is commanded by a single control valve is sent as the signal to the pump compensator valve.
Control Valve Solenoids
The spools of the implement control valves are shifted by pilot oil. The flow of pilot oil to the end of the control valve spools is controlled by the proportional solenoids. Every control valve has a solenoid on each end of the spool.
De-energized
 | |
| Illustration 2 | g02039498 |
Solenoid valve (de-energized solenoid) (14) Spring (15) Valve spool (16) Passage to the hydraulic oil tank (17) Passage from pilot supply oil (18) Passage from the end of the spool for the implement control valve (BB) Cutaway section (CC) Component surface (FF) Activated component (GG) Tank pressure (SS) First pilot pressure reduction | |
When an implement is in the HOLD position, both solenoids on the implement control valve are de-energized. When the solenoid is de-energized, spring (14) forces valve spool (15) upward. In this position, pilot supply oil in passage (17) is blocked. The oil that is from the end of the control valve spool drains through passage (18). The oil flows around valve spool (15) and the oil returns to the hydraulic tank through passage (16) .
Energized
 | |
| Illustration 3 | g02039524 |
Solenoid valve (energized solenoid) (14) Spring (15) Valve spool (16) Passage to the hydraulic oil tank (17) Passage from pilot supply oil (18) Passage from the end of the spool for the implement control valve (BB) Cutaway section (CC) Component surface (FF) Activated component (GG) Tank pressure (SS) First pilot pressure reduction | |
When an implement is activated, the solenoid on one end of the implement control valve is energized. The solenoid forces valve spool (15) downward. In this position, passage (16) to passage (18) is blocked.
Passage (17) is open and pilot supply oil flows around valve spool (15) to passage (18). Pilot oil from passage (18) exerts pressure on the end of the control valve spool and the spool shifts.
The solenoid is a proportional solenoid. The solenoid moves valve spool (15) downward by an amount that is proportional to the amount of movement of the implement control lever. When valve spool (15) is pushed down further, passage (17) is opened more. More pilot oil is allowed into passage (18). The implement control spool shifts proportionally to the pilot oil pressure.
The pressure of the pilot supply oil in passage (17) stays relatively constant, but the pressure of the oil in passage (18) from the implement control valve depends on the amount of flow past spool (15) .
Hydraulic Schematic of the Implement Hydraulic System in the HOLD Position
The following callouts are for the foldout:
(1) Blade lift control valve
(2) Blade tilt control valve
(3) Ripper lift control valve
(4) Return to tank
(5) Main relief valve
(6) Ripper lower solenoid
(7) Blade tilt left solenoid
(8) Blade raise solenoid
(9) Inlet manifold
(10) Inlet port from the pump
(11) Blade lower solenoid
(12) Blade tilt right solenoid
(13) Ripper raise solenoid
(19) Steering motor
(20) Steering charge pump
(21) Steering pump
(22) Steering pump control valve
(23) Cold oil relief valve
(24) Implement pump
(25) Fan drive pump
(26) Implement pump pressure sensor
(27) Fan drive motor
(28) Pressure reducing valve
(29) Accumulator
(30) Implement lockout valve
(31) Pilot filter
(32) Cooler bypass valve
(33) Hydraulic oil cooler
(34) Float boost valve
(35) Vacuum breaker
(36) Hydraulic oil tank
(37) Case drain filters
(38) Ripper lift cylinder
(39) Blade tilt cylinder
(40) Blade lift cylinders
(41) Quick-drop valve
(HPDR) Hydraulic pilot pressure (dozer raise)
(HPDL) Hydraulic pilot pressure (dozer lower)
(HPTR) Hydraulic pilot pressure (tilt right)
(HPTL) Hydraulic pilot pressure (tilt left)
(HPRR) Hydraulic pilot pressure (ripper raise)
(HPRL) Hydraulic pilot pressure (ripper lower)
(HFPD) Hydraulic fan pump discharge
(HA) Implement pump outlet
(HB) Pump signal pressure
(IC) Implement pump case drain (backfill)
(FC) Case drain for the fan motor (backfill)
(CPG) Accumulator
(CP) Pilot valve supply port
(AA) Mechanical connection
(BB) Cutaway section
(FF) Activated component
(GG) Tank pressure
(KK) High pressure
(LL) First pressure reduction
(MM) Second pressure reduction
(RR) Charge pressure or pilot pressure
(SS) First pilot pressure reduction
(UU) Trapped oil
 | |
| Illustration 4 | g02161920 |
When all of the implements are in HOLD, the implement pump is in LOW PRESSURE STANDBY.
The implement pump draws oil from the following areas:
- Hydraulic oil tank (36)
- Any oil that may flow past the cold oil relief valve
Pump supply oil is sent to inlet manifold (9). All of the pump supply oil flows through the inlet manifold to each implement control valve in parallel.
Pump supply oil is also sent to pressure reducing valve (28). The pressure is reduced to pilot pressure. The pilot oil flows through implement lockout valve (30) and pilot filter (31) .
The pilot oil flows from the pilot filter to the solenoids on each control valve. When all of the implements are in the HOLD position, the pilot oil is blocked by the solenoid valves.
Blade Lift Control Valve
HOLD Position
Cutaway of the Blade Lift Control Valve in the HOLD Position
 | |
| Illustration 5 | g02167848 |
Blade Lift Control Valve (HOLD) (8) Blade raise solenoid (11) Blade lower solenoid (42) Passage to hydraulic oil tank (43) Pilot oil (44) Lift valve spool (45) Passage to rod end (46) Chamber (47) Passage to head end (48) Makeup valve (49) Pilot chamber (50) Float boost signal (51) Resolver (52) Internal resolver passage (53) Centering spring (54) Passage from implement pump (55) Load check valve (AA) Mechanical connection (BB) Cutaway section (CC) Component surface (FF) Activated component (GG) Tank pressure (LL) First pressure reduction (SS) First pilot pressure reduction (UU) Trapped oil | |
When the blade lift control valve is in the HOLD position, solenoid (8) and solenoid (11) are de-energized. Pilot chambers (49) are both open to the hydraulic tank. Lift valve spool (44) is held in the center position by centering springs (53) .
In the center position, lift valve spool (44) blocks pump supply oil. Also, the lift valve spool blocks the oil from flowing to the passage to head end (47) and the passage to rod end (45) of the blade lift cylinders. The oil in these passages is trapped and the blade does not move.
Implement pump oil enters the lift control valve from the inlet manifold through the passage from implement pump (54). Pressure increases in chamber (46) because lift valve spool (44) blocks the flow of oil. The pump supply oil is blocked. The compensator on the pump destrokes the swashplate to standby pressure.
BLADE RAISE Position
Hydraulic Schematic of the Implement Hydraulic System in the BLADE RAISE Position
The following callouts are for the foldout:
(1) Blade lift control valve
(2) Blade tilt control valve
(3) Ripper lift control valve
(4) Return to tank
(5) Main relief valve
(6) Ripper lower solenoid
(7) Blade tilt left solenoid
(8) Blade raise solenoid
(9) Inlet manifold
(10) Inlet port from the pump
(11) Blade lower solenoid
(12) Blade tilt right solenoid
(13) Ripper raise solenoid
(19) Steering motor
(20) Steering charge pump
(21) Steering pump
(22) Steering pump control valve
(23) Cold oil relief valve
(24) Implement pump
(25) Fan drive pump
(26) Implement pump pressure sensor
(27) Fan drive motor
(28) Pressure reducing valve
(29) Accumulator
(30) Implement lockout valve
(31) Pilot filter
(32) Cooler bypass valve
(33) Hydraulic oil cooler
(34) Float boost valve
(35) Vacuum breaker
(36) Hydraulic oil tank
(37) Case drain filters
(38) Ripper lift cylinder
(39) Blade tilt cylinder
(40) Blade lift cylinders
(41) Quick-drop valve
(HPDR) Hydraulic pilot pressure (dozer raise)
(HPDL) Hydraulic pilot pressure (dozer lower)
(HPTR) Hydraulic pilot pressure (tilt right)
(HPTL) Hydraulic pilot pressure (tilt left)
(HPRR) Hydraulic pilot pressure (ripper raise)
(HPRL) Hydraulic pilot pressure (ripper lower)
(HFPD) Hydraulic fan pump discharge
(HA) Implement pump outlet
(HB) Pump signal pressure
(IC) Implement pump case drain (backfill)
(FC) Case drain for the fan motor (backfill)
(CPG) Accumulator
(CP) Pilot valve supply port
(AA) Mechanical connection
(BB) Cutaway section
(FF) Activated component
(GG) Tank pressure
(KK) High pressure
(LL) First pressure reduction
(MM) Second pressure reduction
(RR) Charge pressure or pilot pressure
(SS) First pilot pressure reduction
(UU) Trapped oil
 | |
| Illustration 6 | g02167857 |
Cutaway of the Blade Lift Control Valve in the BLADE RAISE Position
 | |
| Illustration 7 | g02167851 |
Blade Lift Control Valve (BLADE RAISE) (8) Blade raise solenoid (11) Blade lower solenoid (42) Passage to hydraulic oil tank (43) Pilot oil (44) Lift valve spool (45) Passage to rod end (46) Chamber (47) Passage to head end (48) Makeup valve (49) Pilot chamber (50) Float boost signal (51) Resolver (52) Internal resolver passage (53) Centering spring (54) Passage from implement pump (55) Load check valve (56) Return passage (57) Signal chamber (58) Left orifice (AA) Mechanical connection (BB) Cutaway section (CC) Component surface (FF) Activated component (GG) Tank pressure (LL) First pressure reduction (SS) First pilot pressure reduction (UU) Trapped oil | |
When the operator moves the blade control lever from HOLD to RAISE, blade raise solenoid (8) is energized. The solenoid valve opens in order to allow pilot supply oil in the passage from pilot manifold (43) into pilot chamber (49) on the right end of lift valve spool (44). The pressure of the pilot oil shifts the lift valve spool (44) to the left.
When lift valve spool (44) shifts, left orifice (58) is exposed to the pressure in the passage to rod end (45). The oil that enters orifice (58) becomes signal oil. The signal oil flows through an internal passage in the middle of lift valve spool (44) to signal chamber (57). From signal chamber (57), the oil flows to resolver (51) .
The signal oil is at the same pressure as the oil in the rod end of the blade lift cylinders. If this pressure is the highest pressure of all the implements, the ball in resolver (51) shifts to the right. The signal is sent to the compensator valve of the implement pump. The implement pump upstrokes in order to meet the demand.
When the increased flow of pump supply oil builds enough pressure to overcome the existing pressure plus the spring force behind load check valve (55), the load check valve shifts to the left. Pump supply oil flows through chamber (46), around lift valve spool (44), and into the passage to rod end (45). After the pump oil exits through the passage to rod end (45), the oil flows to the rod end of the blade lift cylinders. The blade raises.
Oil from the head end of the blade lift cylinders returns to the passage to head end (47). The oil returns to the hydraulic tank.
All of the pressures and forces within the control valve equalize in order to provide smooth operation for the blade lift cylinders.
Makeup Operation
If the blade is in a position above the ground, and a command is given in order to lower the blade, pressure in the rod end of the lift cylinders may exceed the pressure in the head end of the lift cylinders until the blade comes in contact with the ground. This action could occur because the weight of the blade causes the blade to drop quickly. If the pump is not able to supply enough oil, cavitation in the head end of the lift cylinders can occur.
In this situation, the pressure in the passage to head end (47) becomes less than the tank pressure in return passage (56). When the pressure in return passage (56) is enough to overcome the force of the spring behind makeup valve (48), the valve shifts to the right.
The difference in pressure causes tank oil to be drawn past makeup valve (48) into the passage to head end (47). This makeup oil supplements the pump supply oil and the cylinders do not cavitate.
When the blade comes in contact with the ground, the blade stops falling and the implement pump can now supply enough flow. The pressure rises in the passage to head end (47). When the pressure in the passage to head end (47) is high enough, the force of the spring behind makeup valve (48) forces the valve to shift back to the left.
BLADE FLOAT Position
Hydraulic Schematic of the Implement Hydraulic System in the BLADE FLOAT Position
The following callouts are for the foldout:
(1) Blade lift control valve
(2) Blade tilt control valve
(3) Ripper lift control valve
(4) Return to tank
(5) Main relief valve
(6) Ripper lower solenoid
(7) Blade tilt left solenoid
(8) Blade raise solenoid
(9) Inlet manifold
(10) Inlet port from the pump
(11) Blade lower solenoid
(12) Blade tilt right solenoid
(13) Ripper raise solenoid
(19) Steering motor
(20) Steering charge pump
(21) Steering pump
(22) Steering pump control valve
(23) Cold oil relief valve
(24) Implement pump
(25) Fan drive pump
(26) Implement pump pressure sensor
(27) Fan drive motor
(28) Pressure reducing valve
(29) Accumulator
(30) Implement lockout valve
(31) Pilot filter
(32) Cooler bypass valve
(33) Hydraulic oil cooler
(34) Float boost valve
(35) Vacuum breaker
(36) Hydraulic oil tank
(37) Case drain filters
(38) Ripper lift cylinder
(39) Blade tilt cylinder
(40) Blade lift cylinders
(41) Quick-drop valve
(HPDR) Hydraulic pilot pressure (dozer raise)
(HPDL) Hydraulic pilot pressure (dozer lower)
(HPTR) Hydraulic pilot pressure (tilt right)
(HPTL) Hydraulic pilot pressure (tilt left)
(HPRR) Hydraulic pilot pressure (ripper raise)
(HPRL) Hydraulic pilot pressure (ripper lower)
(HFPD) Hydraulic fan pump discharge
(HA) Implement pump outlet
(HB) Pump signal pressure
(IC) Implement pump case drain (backfill)
(FC) Case drain for the fan motor (backfill)
(CPG) Accumulator
(CP) Pilot valve supply port
(AA) Mechanical connection
(BB) Cutaway section
(FF) Activated component
(GG) Tank pressure
(KK) High pressure
(LL) First pressure reduction
(MM) Second pressure reduction
(RR) Charge pressure or pilot pressure
(SS) First pilot pressure reduction
(UU) Trapped oil
 | |
| Illustration 8 | g02167862 |
Cutaway of the Blade Lift Control Valve in the BLADE FLOAT Position
 | |
| Illustration 9 | g02303394 |
Blade Lift Control Valve (FLOAT) (8) Blade raise solenoid (11) Blade lower solenoid (42) Passage to hydraulic oil tank (43) Pilot oil (44) Lift valve spool (45) Passage to rod end (46) Chamber (47) Passage to head end (48) Makeup valve (49) Pilot chamber (50) Float boost signal (51) Resolver (52) Internal resolver passage (53) Centering spring (54) Passage from implement pump (55) Load check valve (58) Left orifice (59) Return passage for the rod end (60) Return passage for the head end (61) Right orifice (AA) Mechanical connection (BB) Cutaway section (CC) Component surface (FF) Activated component (GG) Tank pressure (LL) First pressure reduction (SS) First pilot pressure reduction (UU) Trapped oil | |
When the operator moves the blade control lever into the FLOAT position, left solenoid (11) is energized. The solenoid valve opens in order to allow pilot supply oil into pilot chamber (49) on the left end of lift valve spool (44). The pressure of the pilot oil in pilot chamber (49) shifts the lift valve spool (44) all the way to the right.
When lift valve spool (44) shifts to the right into the FLOAT position, pump supply oil is blocked from entering the passage to rod end (45) and the passage to head end (47). The passage to head end (47) is open to return passage (60). The passage to rod end (45) is open to return passage (59). When both ends of the lift cylinders are open to the tank, the blade is free to "float" in order to follow the contour of the ground.
When lift valve spool (44) shifts, right orifice (61) is exposed to tank pressure in the passage to head end (47) and left orifice (58) is blocked. No signal is sent to the implement pump. The pump destrokes to the LOW PRESSURE STANDBY position.
Pilot pressure must overcome the force of right centering spring (53) in order to hold valve spool (44) all the way to the right in the FLOAT position. Standby pressure is not enough to overcome the force of the centering springs.
When the blade control lever is moved to the FLOAT position, an electrical signal is sent to the valve for float boost signal (34). When the valve for the float boost signal (34) is activated, pilot oil is directed through the resolver network of the load sensing circuit to the compensator valve on the implement pump. The additional signal in the load sensing circuit upstrokes the implement pump which provides enough pressure in pilot chamber (49) in order to hold lift valve spool (44) in the FLOAT position.
Tilt Right Position
Hydraulic Schematic of the Implement Hydraulic System in the Tilt Right Position
The following callouts are for the foldout:
(1) Blade lift control valve
(2) Blade tilt control valve
(3) Ripper lift control valve
(4) Return to tank
(5) Main relief valve
(6) Ripper lower solenoid
(7) Blade tilt left solenoid
(8) Blade raise solenoid
(9) Inlet manifold
(10) Inlet port from the pump
(11) Blade lower solenoid
(12) Blade tilt right solenoid
(13) Ripper raise solenoid
(19) Steering motor
(20) Steering charge pump
(21) Steering pump
(22) Steering pump control valve
(23) Cold oil relief valve
(24) Implement pump
(25) Fan drive pump
(26) Implement pump pressure sensor
(27) Fan drive motor
(28) Pressure reducing valve
(29) Accumulator
(30) Implement lockout valve
(31) Pilot filter
(32) Cooler bypass valve
(33) Hydraulic oil cooler
(34) Float boost valve
(35) Vacuum breaker
(36) Hydraulic oil tank
(37) Case drain filters
(38) Ripper lift cylinder
(39) Blade tilt cylinder
(40) Blade lift cylinders
(41) Quick-drop valve
(HPDR) Hydraulic pilot pressure (dozer raise)
(HPDL) Hydraulic pilot pressure (dozer lower)
(HPTR) Hydraulic pilot pressure (tilt right)
(HPTL) Hydraulic pilot pressure (tilt left)
(HPRR) Hydraulic pilot pressure (ripper raise)
(HPRL) Hydraulic pilot pressure (ripper lower)
(HFPD) Hydraulic fan pump discharge
(HA) Implement pump outlet
(HB) Pump signal pressure
(IC) Implement pump case drain (backfill)
(FC) Case drain for the fan motor (backfill)
(CPG) Accumulator
(CP) Pilot valve supply port
(AA) Mechanical connection
(BB) Cutaway section
(FF) Activated component
(GG) Tank pressure
(KK) High pressure
(LL) First pressure reduction
(MM) Second pressure reduction
(RR) Charge pressure or pilot pressure
(SS) First pilot pressure reduction
(UU) Trapped oil
 | |
| Illustration 10 | g02163796 |
Cutaway of the Blade Tilt Control Valve in the Tilt Right Position
 | |
| Illustration 11 | g02166758 |
Blade tilt control valve (TILT RIGHT) (8) Tilt left solenoid (11) Tilt right solenoid (42) Passage to hydraulic oil tank (43) Pilot oil (45) Passage to head end (46) Chamber (47) Passage to rod end (49) Pilot chamber (51) Resolver (52) Internal resolver passage (53) Centering spring (54) Passage from implement pump (55) Load check valve (58) Left orifice (59) Return passage for the head end (60) Return passage for the rod end (61) Right orifice (62) Line relief valves (63) Spring (64) Spring chamber (65) Flow control valve spool (66) Resolver signal from prior valve (69) Tilt valve spool (AA) Mechanical connection (BB) Cutaway section (CC) Component surface (FF) Activated component (GG) Tank pressure (LL) First pressure reduction (SS) First pilot pressure reduction (UU) Trapped oil | |
When the operator moves the blade control lever into the TILT RIGHT position, left solenoid (11) is energized. The solenoid valve opens in order to allow pilot supply oil into pilot chamber (49) on the left end of lift valve spool (69). The pressure of the pilot oil in pilot chamber (49) shifts the lift valve spool (69) to the right.
When tilt valve spool (69) shifts to the right into the TILT RIGHT position, the passage from head end (45) is open to the tank. The passage to rod end (47) is opened to pump supply. The blade will tilt to the right.
When tilt valve spool (69) shifts, right orifice (61) is exposed to the pressure in the passage to rod end (47). The oil that enters orifice (61) becomes signal oil. The signal oil flows through an internal passage in the middle of tilt valve spool (69) to the signal chamber. From the signal chamber, the oil flows to resolver (51) and to spring chamber (64) .
If this pressure is the highest pressure of all the implements, the ball in resolver (51) shifts to the right. The signal then goes to the compensator valve of the implement pump. The pump upstrokes in order to meet the demand.
When the increased flow of pump supply oil builds enough pressure to overcome the existing pressure plus the spring force behind load check valve (55), the load check valve shifts to the left. Pump supply oil flows through chamber (46), around tilt valve spool (69), and into the passage to rod end (47). After the pump oil exits through the passage to rod end (48), the oil flows to the rod end of the blade tilt cylinder. The blade tilts to the right.
Oil from the head end of the blade tilt cylinder returns through the passage to head end (45). The oil then flows around tilt valve spool (69) and returns to the hydraulic tank.
At the same time, the signal pressure in spring chamber (64) plus the force of spring (63) moves flow control valve spool (65) to the left. This action allows the throttling slots in flow control valve spool (65) to meter the flow of pump supply oil.
All of the pressures and forces within the control valve equalize in order to provide smooth operation for the blade tilt cylinder.
VPATAngle Right Position
Hydraulic Schematic of the Implement Hydraulic System in the Angle Right Position
The following callouts are for the foldout:
(1) Blade lift control valve
(2) Blade tilt control valve
(3) Ripper lift control valve
(4) Return to tank
(5) Main relief valve
(6) Ripper lower solenoid
(7) Blade tilt left solenoid
(8) Blade raise solenoid
(9) Inlet manifold
(10) Inlet port from the pump
(11) Blade lower solenoid
(12) Blade tilt right solenoid
(13) Ripper raise solenoid
(19) Steering motor
(20) Steering charge pump
(21) Steering pump
(22) Steering pump control valve
(23) Cold oil relief valve
(24) Implement pump
(25) Fan drive pump
(26) Implement pump pressure sensor
(27) Fan drive motor
(28) Pressure reducing valve
(29) Accumulator
(30) Implement lockout valve
(31) Pilot filter
(32) Cooler bypass valve
(33) Hydraulic oil cooler
(34) Float boost valve
(35) Vacuum breaker
(36) Hydraulic oil tank
(37) Case drain filters
(38) Ripper lift cylinder
(39) Blade tilt cylinder
(40) Blade lift cylinders
(41) Quick-drop valve
(HPDR) Hydraulic pilot pressure (dozer raise)
(HPDL) Hydraulic pilot pressure (dozer lower)
(HPTR) Hydraulic pilot pressure (tilt right)
(HPTL) Hydraulic pilot pressure (tilt left)
(HPRR) Hydraulic pilot pressure (ripper raise)
(HPRL) Hydraulic pilot pressure (ripper lower)
(HFPD) Hydraulic fan pump discharge
(HA) Implement pump outlet
(HB) Pump signal pressure
(IC) Implement pump case drain (backfill)
(FC) Case drain for the fan motor (backfill)
(CPG) Accumulator
(CP) Pilot valve supply port
(AA) Mechanical connection
(BB) Cutaway section
(FF) Activated component
(GG) Tank pressure
(KK) High pressure
(LL) First pressure reduction
(MM) Second pressure reduction
(RR) Charge pressure or pilot pressure
(SS) First pilot pressure reduction
(UU) Trapped oil
 | |
| Illustration 12 | g02163804 |
Cutaway of the Blade Angle Control Valve in the Angle Right Position
 | |
| Illustration 13 | g02167533 |
Blade angle control valve (Angle Right) (8) Angle left solenoid (11) Angle right solenoid (42) Passage to hydraulic oil tank (43) Pilot oil (45) Passage to head end (46) Chamber (47) Passage to rod end (49) Pilot chamber (51) Resolver (52) Internal resolver passage (53) Centering spring (54) Passage from implement pump (55) Load check valve (58) Left orifice (59) Return passage for the head end (60) Return passage for the rod end (61) Right orifice (62) Line relief valves (63) Spring (64) Spring chamber (65) Flow control valve spool (66) Resolver signal from prior valve (67) Angle valve spool (AA) Mechanical connection (BB) Cutaway section (CC) Component surface (FF) Activated component (GG) Tank pressure (LL) First pressure reduction (SS) First pilot pressure reduction (UU) Trapped oil | |
When the operator moves the blade control lever into the ANGLE RIGHT position, left solenoid (11) is energized. The solenoid valve opens in order to allow pilot supply oil into pilot chamber (49) on the left end of angle valve spool (67). The pressure of the pilot oil in pilot chamber (49) shifts the angle valve spool (67) to the right.
When angle valve spool (67) shifts to the right into the ANGLE RIGHT position, the passage from head end (45) is open to the tank. The passage to rod end (47) is opened to pump supply. The blade will angle to the right.
When angle valve spool (67) shifts, right orifice (61) is exposed to the pressure in the passage to rod end (47). The oil that enters orifice (61) becomes signal oil. The signal oil flows through an internal passage in the middle of angle valve spool (67) to the signal chamber. From the signal chamber, the oil flows to resolver (51) and to spring chamber (64) .
If this pressure is the highest pressure of all the implements, the ball in resolver (51) shifts to the right. The signal then goes to the compensator valve of the implement pump. The pump upstrokes in order to meet the demand.
When the increased flow of pump supply oil builds enough pressure to overcome the existing pressure plus the spring force behind load check valve (55), the load check valve shifts to the left. Pump supply oil flows through chamber (46), around angle valve spool (67), and into the passage to rod end (47). After the pump oil exits through the passage to rod end (48), the oil flows to the rod end of the blade angle cylinder. The blade angles to the right.
Oil from the head end of the blade tilt cylinder returns through the passage to head end (45). The oil then flows around angle valve spool (67) and returns to the hydraulic tank.
At the same time, the signal pressure in spring chamber (64) plus the force of spring (63) moves flow control valve spool (65) to the left. This action allows the throttling slots in flow control valve spool (65) to meter the flow of pump supply oil.
All of the pressures and forces within the control valve equalize in order to provide smooth operation for the blade angle cylinder.
Ripper Raise Position
Hydraulic Schematic of the Implement Hydraulic System in the Ripper Raise Position
The following callouts are for the foldout:
(1) Blade lift control valve
(2) Blade tilt control valve
(3) Ripper lift control valve
(4) Return to tank
(5) Main relief valve
(6) Ripper lower solenoid
(7) Blade tilt left solenoid
(8) Blade raise solenoid
(9) Inlet manifold
(10) Inlet port from the pump
(11) Blade lower solenoid
(12) Blade tilt right solenoid
(13) Ripper raise solenoid
(19) Steering motor
(20) Steering charge pump
(21) Steering pump
(22) Steering pump control valve
(23) Cold oil relief valve
(24) Implement pump
(25) Fan drive pump
(26) Implement pump pressure sensor
(27) Fan drive motor
(28) Pressure reducing valve
(29) Accumulator
(30) Implement lockout valve
(31) Pilot filter
(32) Cooler bypass valve
(33) Hydraulic oil cooler
(34) Float boost valve
(35) Vacuum breaker
(36) Hydraulic oil tank
(37) Case drain filters
(38) Ripper lift cylinder
(39) Blade tilt cylinder
(40) Blade lift cylinders
(41) Quick-drop valve
(HPDR) Hydraulic pilot pressure (dozer raise)
(HPDL) Hydraulic pilot pressure (dozer lower)
(HPTR) Hydraulic pilot pressure (tilt right)
(HPTL) Hydraulic pilot pressure (tilt left)
(HPRR) Hydraulic pilot pressure (ripper raise)
(HPRL) Hydraulic pilot pressure (ripper lower)
(HFPD) Hydraulic fan pump discharge
(HA) Implement pump outlet
(HB) Pump signal pressure
(IC) Implement pump case drain (backfill)
(FC) Case drain for the fan motor (backfill)
(CPG) Accumulator
(CP) Pilot valve supply port
(AA) Mechanical connection
(BB) Cutaway section
(FF) Activated component
(GG) Tank pressure
(KK) High pressure
(LL) First pressure reduction
(MM) Second pressure reduction
(RR) Charge pressure or pilot pressure
(SS) First pilot pressure reduction
(UU) Trapped oil
 | |
| Illustration 14 | g02163811 |
Cutaway of the Ripper Control Valve in the Ripper Raise Position
 | |
| Illustration 15 | g02163815 |
Ripper Control Valve (Ripper Raise) (8) Ripper raise solenoid (11) Ripper lower solenoid (42) Passage to hydraulic oil tank (43) Pilot oil (45) Passage to rod end (46) Chamber (47) Passage to head end (48) Makeup valve (49) Pilot chamber (51) Resolver (52) Internal resolver passage (53) Centering spring (54) Passage from implement pump (55) Load check valve (58) Left orifice (59) Return passage for the rod end (60) Return passage for the head end (61) Right orifice (66) Resolver signal from prior valve (68) Ripper valve spool (AA) Mechanical connection (BB) Cutaway section (CC) Component surface (FF) Activated component (GG) Tank pressure (LL) First pressure reduction (SS) First pilot pressure reduction (UU) Trapped oil | |
When the operator moves the ripper control lever from HOLD to RAISE, left solenoid (11) is energized. The solenoid valve opens in order to allow pilot supply oil into pilot chamber (49) on the left end of ripper valve spool (68). The pressure of the pilot oil shifts the lift valve spool to the right.
When ripper valve spool (68) shifts, right orifice (61) is exposed to the pressure in the passage to head end (47). The oil that enters orifice (61) becomes signal oil. The signal oil flows through an internal passage in the middle of ripper valve spool (68) to the signal chamber. From the signal chamber, the oil flows to resolver (51) .
If this pressure is the highest pressure of all the implements, the ball in resolver (51) shifts to the right. The signal is then sent to the compensator valve in the implement pump. The pump upstrokes in order to meet the demand.
When the increased flow of pump supply oil builds enough pressure to overcome the existing pressure plus the spring force behind load check valve (55), the load check valve shifts to the left. Pump supply oil flows through chamber (46), around ripper valve spool (68), and into the passage to head end (47). The oil flows to the head end of the ripper lift cylinder and the ripper raises.
Oil from the rod end of the ripper lift cylinder returns through the passage to rod end (45). The oil then flows around ripper valve spool (68) and to the hydraulic tank.