D10R Implement Systems

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TECHNICAL

PRESENTA

TION

D11R TRACK-TYPE TRACTOR

IMPLEMENT SYSTEMS

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MEETING

GUIDE

692

692 SLIDES

SLIDES

AND

SCRIPT

AUDIENCE

Level II--Service personnel who understand the principles of machine systems operation, diagnostic Level II--Service personnel who understand the principles of machine systems operation, diagnostic equipment, and procedures for testing and adjusting.

equipment, and procedures for testing and adjusting.

CONTENT

This presentation discusses the operation of the implement hydraulic system for the D11R Track-type This presentation discusses the operation of the implement hydraulic system for the D11R Track-type Tractor.

Tractor.

OBJECTIVES

After learning the information in this presentation, the serviceman will be able to: After learning the information in this presentation, the serviceman will be able to:

1.

1. locate and identify all locate and identify all major components in major components in the implement hydraulic system;the implement hydraulic system; 2.

2. locate and identify all locate and identify all filters, drains, and test points;filters, drains, and test points; 3.

3. explain the function of each explain the function of each component in the implement component in the implement hydraulic system; andhydraulic system; and 4.

4. trace the flow trace the flow of oil of oil through the implement through the implement hydraulic system.hydraulic system.

REFERENCES

D D1111R R TTrraacckk--ttyyppe e TTrraaccttoor r SSeerrvviicce e MMaannuuaal l ((99TTR R 11--UUpp)) SSEENNRR11777755 D D1111R R TTrraacckk--ttyyppe e TTrraaccttoor r SSeerrvviicce e MMaannuuaal l ((88ZZR R 11--UUpp)) SSEENNRR99440000

PREREQUISITES

I Inntteerraaccttiivve e VViiddeeo o CCoouurrsse e ""FFuunnddaammeennttaalls s oof f MMoobbiille e HHyyddrraauulliiccss" " ((CCD D RROOMM)) TTEECCDD99000011 S STTMMG G 55446 6 ""GGrraapphhiic c FFlluuiid d PPoowweer r SSyymmbboollss"" SSEESSVV11554466

SUPPLEMENTARY TRAINING MATERIAL

S

STTMMG G 66779 9 ""DD1100R R TTrraacckk--ttyyppe e TTrraaccttoorr----IInnttrroodduuccttiioonn"" SSEESSVV11667799 STMG 527

STMG 527 "D11N "D11N Track-type TTrack-type Tractor--Part 2: ractor--Part 2: Undercarriage, Implements, andUndercarriage, Implements, and O

Oppeerraattoorr’’ssSSttaattiioonn"" SSEESSVV11552277 V

Viiddeeo o TTaappe e ""DD1111R R TTrraacckk--ttyyppe e TTrraaccttoorr//DD1111R R CCD D CCaarrrryyddoozzeerr----IInnttrroodduuccttiioonn"" SSEEVVNN44117733

Estimated T

Estimated Time: ime: 2 2 HoursHours Visuals:

Visuals: 27 (2 27 (2 X 2) X 2) SlidesSlides Serviceman Handouts:

Serviceman Handouts: 18 18 Line DLine Drawingsrawings Form: SESV1692

Form: SESV1692 Date: 10/97

Date: 10/97

©

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INTROD

INTRODUCTIONUCTION...5...5

IMPLEMEN IMPLEMENT HYDRAULIT HYDRAULIC SYSTEM...C SYSTEM...6...6

Bulldozer Tilt Circuit...9

Bulldozer Lift Circuit...12

Quick-dr Quick-drop op VValvesalves...19...19

Fan Drive Hydra Fan Drive Hydraulic System...ulic System...25...25

Ripper and Pilot Circuits...26

Dual T Dual Tilt Vilt Valvealve...33...33

CONCLUSION...40

SLIDE LIST...41

SER SERVICEMAVICEMAN'S N'S HANDOUHANDOUTSTS...42...42

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INSTRUCTOR NOTES

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• 35350808B engB engineine

1

INTRODUCTION

This presentation discusses the major design features of the implement This presentation discusses the major design features of the implement hydraulic systems for the updated D11R Track-type Tractor (Serial hydraulic systems for the updated D11R Track-type Tractor (Serial Number 9TR 1-Up).

Number 9TR 1-Up). The D1The D11R is an 1R is an elevated sprocket design tractorelevated sprocket design tractor equipped with the Power Train Electronic Control System and Finger Tip equipped with the Power Train Electronic Control System and Finger Tip Control steering.

Control steering.

This tractor is powered by the 3508B turbocharged and aftercooled engine This tractor is powered by the 3508B turbocharged and aftercooled engine rated at 634 kW (850 hp) with a 25 percent net torque rise for excellent rated at 634 kW (850 hp) with a 25 percent net torque rise for excellent lugging performance.

lugging performance. The power The power from the from the engine is transferred through engine is transferred through aa torque divider that results in maximum torque multiplication during heavy torque divider that results in maximum torque multiplication during heavy loading. loading.

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2

•

• ConContintinuouuous flow as flow att

minimum pressure

with controls in HOLD

•

• Two Two sectiosection gn gear-tear-typeype

pump

•

• Pilot Pilot operatoperated coed controlntrol

valves valves DUAL TILT DUAL TILT CONTROL VALVE CONTROL VALVE QUICK-DROP QUICK-DROP VALVES VALVES RIPPER RIPPER CONTROL VALVE CONTROL VALVE HYDRAULIC HYDRAULIC TANK TANK PILOT VALVE PILOT VALVE AND DOZER AND DOZER CONTROL VALVE CONTROL VALVE IMPLEMENT IMPLEMENT PUMP PUMP FAN MOTOR AND

FAN MOTOR AND MAKEUP VALVE MAKEUP VALVE

OIL COOLER AND OIL COOLER AND BYPASS VALVE BYPASS VALVE FAN FAN PUMPS PUMPS

IMPLEMENT HYDRAULIC SYSTEM

IMPLEMENT HYDRAULIC SYSTEM COMPONENTSCOMPONENTS

IMPLEMENT HYDRAULIC SYSTEM

The implement hydraulic system for the D11R is a continuous flow design The implement hydraulic system for the D11R is a continuous flow design that permits minimum pressure in the system when the implement control that permits minimum pressure in the system when the implement control valves are not activated.

valves are not activated. The pump for The pump for operation of the bulldozer, operation of the bulldozer, ripper,ripper, and oil cooling circuits is a two section gear-type pump (large and small and oil cooling circuits is a two section gear-type pump (large and small sections).

sections).

The system components

The system components include: include: the pump, pilot the pump, pilot operated control valves,operated control valves, demand control fan pumps, dozer control valve, quick-drop valves, dual demand control fan pumps, dozer control valve, quick-drop valves, dual tilt control valve, and

tilt control valve, and a ripper control a ripper control valve. valve. The system componentsThe system components control the flow of hydraulic oil to the appropriate implement cylinders. control the flow of hydraulic oil to the appropriate implement cylinders.

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•

• HydHydrauraulic lic tantankk

components: components: 1. 1. OiOil fl filill tl tububee 2. 2. MaManunual al air air veventnt 3.

3. HydHydrauraulic lic oil oil filfilterterss

4. 4. SiSighght t gagaugugee 5. 5. S•S•O•O•S tS tapap 6. 6. TaTank nk drdraiainn 3 3

The hydraulic tank is located on the right fender just outside the operator's The hydraulic tank is located on the right fender just outside the operator's compartment.

compartment. The oil fill tube The oil fill tube and cap (1) and cap (1) are located on the are located on the top of thetop of the tank.

tank. Inside the fill tube is Inside the fill tube is a fine mesh a fine mesh screen which removes largescreen which removes large particles of dirt or foreign

particles of dirt or foreign material from the oil as material from the oil as the tank is the tank is filled. filled. AA manual air vent (2) and the breaker relief valve (not visible) are located manual air vent (2) and the breaker relief valve (not visible) are located near the filters.

near the filters. The vacuum breaker relief valve The vacuum breaker relief valve has a pressure setting of has a pressure setting of 3.5 kPa (.5 psi).

3.5 kPa (.5 psi). TTwo hydraulic oil filters (3) wo hydraulic oil filters (3) are located inside the tank.are located inside the tank. The oil level sight gauge (4) on the front of the tank permits an easy The oil level sight gauge (4) on the front of the tank permits an easy check of the

check of the hydraulic system oil level. hydraulic system oil level. Always clean the sight Always clean the sight gauge togauge to be sure the

be sure the oil level is visible. oil level is visible. Dirt and stains on Dirt and stains on the glass frequently givethe glass frequently give the appea

the appearance of a france of a full tank. ull tank. A scheduleA scheduled oil sampd oil sampling (S•O•S) ling (S•O•S) taptap(5)(5) and tank drain (6) are located on the front of the tank.

and tank drain (6) are located on the front of the tank.

NOTE:

NOTE: The capacity of the D1The capacity of the D11R hydraulic system is 1R hydraulic system is approximatelyapproximately

205 Liters (54 gal.). 205 Liters (54 gal.). 3 3 2 2 1 1 5 5 6 6 4 4

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4

•

• DozDozer coner controtrol valvel valve

component locations

•

• ManManuallually opery operateatedd

dozer lift spool

•

• PiloPilot opert operateated bladed blade

tilt spool

FROM SMALL PUMP FROM SMALL PUMP

FROM LARGE PUMP FROM LARGE PUMP FROM PILOT VALVE FROM PILOT VALVE

ROD END LIFT CYLINDER ROD END LIFT CYLINDER HEAD END LIFT CYLINDER HEAD END LIFT CYLINDER ROD END ROD END TILT CYLINDER TILT CYLINDER HEAD END HEAD END TILT CYLINDER TILT CYLINDER LIFT SPOOL LIFT SPOOL LIFT RELIEF LIFT RELIEF VALVE VALVE TILT TILT SPOOL SPOOL

DOZER CONTROL VALVE

HOLD HOLD

The dozer control valve is located below the operator's station on the right The dozer control valve is located below the operator's station on the right side of

side of the machine. the machine. Inside the Inside the control valve control valve are two are two spools. spools. One spool One spool isis for blade lift and

for blade lift and lower and one lower and one spool is for blade spool is for blade tilt. tilt. The blade lift spoolThe blade lift spool is manually operated and the blade tilt spool is operated by pilot oil.

is manually operated and the blade tilt spool is operated by pilot oil.

The manu

The manually operatally operated dozer lied dozer lift spoolft spoolhas four pohas four positions: sitions: RAISE,RAISE, HOLD, LOWER, and FLOA

HOLD, LOWER, and FLOATT. . Only the FLOAOnly the FLOAT position has a deT position has a detent.tent. The pilot operated blade tilt spool has three positions:

The pilot operated blade tilt spool has three positions: TILTILT RIGHTT RIGHT,, HOLD, and TIL

HOLD, and TILT LEFTT LEFT. . None of these positions has a detent.None of these positions has a detent.

The tilt circuit receives oil from

The tilt circuit receives oil from the small section of the small section of the pump. the pump. When theWhen the circuit is not in use, the oil joins the large pump section oil flow to the lift circuit is not in use, the oil joins the large pump section oil flow to the lift circuit.

circuit. If neither circuit is in If neither circuit is in use, the dump use, the dump valve opens and sends valve opens and sends oiloil flow to the

flow to the tank. tank. Both the tilt and Both the tilt and lift circuits have load check lift circuits have load check valves andvalves and relief valves.

relief valves. The lift circuit has makeup The lift circuit has makeup valves for both the valves for both the rod and headrod and head ends of the lift cylinders.

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5 5 A A AA SECTION A-A SECTION A-A

DOZER TILT SPOOL

HOLD HOLD

TILT RIGHT

TILT RIGHT TILT LEFTTILT LEFT

Bulldozer Tilt Circuit

The tilt spool ha

The tilt spool has three positions: s three positions: TILTILT RIGHTT RIGHT, HOLD, and TILT LEFT, HOLD, and TILT LEFT.. The tilt spool is hydraulically operated by pilot pressure from a pilot valve The tilt spool is hydraulically operated by pilot pressure from a pilot valve which is controlled by the

which is controlled by the blade control lever. blade control lever. Movement of the lever Movement of the lever toto the right sends pilot pressure oil to the left end of the of the tilt valve the right sends pilot pressure oil to the left end of the of the tilt valve spool.

spool. The pilot pressure moves the The pilot pressure moves the spool to the right spool to the right and sends oil fromand sends oil from the pump to the rod end

the pump to the rod end of the tilt cylinder, and the of the tilt cylinder, and the blade tilts right. blade tilts right. LeverLever movement to the left sends pilot pressure oil to the right end of the spool. movement to the left sends pilot pressure oil to the right end of the spool. The spool moves to the left, sends pump oil to the tilt cylinders, and the The spool moves to the left, sends pump oil to the tilt cylinders, and the blade tilts left.

blade tilts left. When the blade control lever When the blade control lever is released from either theis released from either the TILT RIGHT or TILT LEFT position, springs return the tilt spool to the TILT RIGHT or TILT LEFT position, springs return the tilt spool to the HOLD position.

HOLD position.

In the HOLD position, the oil from the small section of the pump goes In the HOLD position, the oil from the small section of the pump goes around the tilt spool and joins the oil from the large section of the pump. around the tilt spool and joins the oil from the large section of the pump. The oil then opens the dump valve and returns to the tank.

The oil then opens the dump valve and returns to the tank.

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• Tilt Tilt circuit circuit compocomponentnent

locations

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6

•

• PiloPilot oil mot oil moves tves tiltilt

spool to right

•

• PrePressussure opere opens loans loadd

check valve

•

• Oil goeOil goes to s to tilt ctilt cylinderylinder

to retract rod to retract rod A A AA SECTION A-A SECTION A-A

DOZER TILT SPOOL

TILT RIGHT TILT RIGHT

TILT RIGHT

TILT RIGHT TILT LEFTTILT LEFT

When the dozer control lever is moved to the TILT RIGHT position, pilot When the dozer control lever is moved to the TILT RIGHT position, pilot oil goes to the

oil goes to the left end of the left end of the tilt spool. tilt spool. The pressure of the The pressure of the pilot oilpilot oil moves the tilt spool to the TILT

moves the tilt spool to the TILT RIGHT position. RIGHT position. In the TILIn the TILT RIGHTT RIGHT position, the oil from the small section of the pump cannot go through the position, the oil from the small section of the pump cannot go through the control valve and

control valve and the pressure of the pressure of the oil increases. the oil increases. The increased pressureThe increased pressure of the oil opens

of the oil opens the load check valve. the load check valve. The pump oil The pump oil goes through thegoes through the open load check valve and around the tilt spool to the rod end of the tilt open load check valve and around the tilt spool to the rod end of the tilt cylinder.

cylinder. The tilt cylinder, The tilt cylinder, which is connected to which is connected to the upper rear of the upper rear of thethe blade, retracts and causes the right end of the blade to move downward or blade, retracts and causes the right end of the blade to move downward or TILT RIGHT.

TILT RIGHT.

When the dozer control lever is released, the pilot oil at the left end of the When the dozer control lever is released, the pilot oil at the left end of the tilt spool is drained.

tilt spool is drained. The spring at the The spring at the right end of the right end of the tilt spool moves thetilt spool moves the spool to the

spool to the HOLD position. HOLD position. In the HOLD In the HOLD position, the oil in the position, the oil in the headhead and rod ends

and rod ends of the tilt cylinder is of the tilt cylinder is blocked. blocked. The tilt angle of The tilt angle of the blade willthe blade will not change until the dozer control lever is moved.

not change until the dozer control lever is moved.

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•Tilt circuit relief valve

•Tilt circuit relief valve With the tilt spool in the TILT RIGHT position, flow from the smallWith the tilt spool in the TILT RIGHT position, flow from the small section of the pump does not combine with flow from the large section. section of the pump does not combine with flow from the large section. Pilot oil at the left end of the tilt spool has moved the spool to the right. Pilot oil at the left end of the tilt spool has moved the spool to the right. Flow from the small section of the pump goes around the tilt spool and is Flow from the small section of the pump goes around the tilt spool and is sent to the

sent to the rod end of rod end of the tilt cylinder. the tilt cylinder. Because the small section flowBecause the small section flow cannot combine with the oil in the center chamber, the dump valve for the cannot combine with the oil in the center chamber, the dump valve for the dozer lift circuit does

dozer lift circuit does not control the not control the tilt circuit pressure. tilt circuit pressure. Instead, the tiltInstead, the tilt relief valve (at the top of the valve body) is used to limit the pressure in relief valve (at the top of the valve body) is used to limit the pressure in the tilt circuit.

the tilt circuit. When the When the tilt cylinder pressure increases to tilt cylinder pressure increases to 24300 kPa24300 kPa (3525 psi), the pilot valve for tilt relief will open and drain the spring (3525 psi), the pilot valve for tilt relief will open and drain the spring chamber behind the

chamber behind the valve spool. valve spool. This condition permits the This condition permits the valve spoolvalve spool to open and limit the pressure in the tilt circuit.

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7

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• LifLift t circircuitcuit

components

FROM LARGE PUMP FROM LARGE PUMP LIFT RELIEF LIFT RELIEF VALVE VALVE LIFT SPOOL LIFT SPOOL

DOZER LIFT SPOOL

HOLD HOLD

Bulldozer Lift Circuit

The lift spool has four positions:

The lift spool has four positions: RAISE, HOLD, LOWER, and FLOARAISE, HOLD, LOWER, and FLOATT.. The lift spool is

The lift spool is manually operated by the blade manually operated by the blade control lever. control lever. MovementMovement of the lever to the rear sends pressure oil to the rod end of the lift

of the lever to the rear sends pressure oil to the rod end of the lift cylinders, causing the blade

cylinders, causing the blade to RAISE. to RAISE. Forward movement of Forward movement of the dozerthe dozer control lever sends pressure oil to the head end of the lift cylinders, control lever sends pressure oil to the head end of the lift cylinders, causing the blade to

causing the blade to LOWER. LOWER. If the lever is If the lever is pushed forward past thepushed forward past the LOWER position, the lever will go int

LOWER position, the lever will go into the FLOAo the FLOAT position. T position. The FLOAThe FLOATT position is the only position with a detent.

position is the only position with a detent. In the FLOAIn the FLOAT position, theT position, the blade is free to move up or down according to outside forces.

blade is free to move up or down according to outside forces.

In the HOLD position, oil from the large section of the pump goes to the In the HOLD position, oil from the large section of the pump goes to the lift spool where it joins the oil from the tilt circuit.

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8

•

• HOLHOLD D pospositioitionn

ROD END LIFT CYLINDER ROD END LIFT CYLINDER HEAD END LIFT CYLINDER HEAD END LIFT CYLINDER ROD END ROD END TILT CYLINDER TILT CYLINDER HEAD END HEAD END TILT CYLINDER TILT CYLINDER LIFT SPOOL LIFT SPOOL LIFT RELIEF LIFT RELIEF VALVE VALVE TILT TILT SPOOL SPOOL SHUTTLE SHUTTLE VALVE VALVE BALL BALL RESOLVER RESOLVER

FROM LARGE PUMP FROM LARGE PUMP FROM PILOT VALVE FROM PILOT VALVE DOZER CONTROL VALVE

DOZER CONTROL VALVE

HOLD HOLD

When the valve spools in both the dozer control valve and the ripper When the valve spools in both the dozer control valve and the ripper control valve are in the HOLD position, the pressure of the supply oil control valve are in the HOLD position, the pressure of the supply oil (from both the small and large sections of the pump) through the dozer (from both the small and large sections of the pump) through the dozer control valve is maintained at approximately 700 kPa (100 psi).

control valve is maintained at approximately 700 kPa (100 psi).

The dozer lift spool is a "closed-center" spool, and the blade tilt spool is The dozer lift spool is a "closed-center" spool, and the blade tilt spool is an "open-center" spool.

an "open-center" spool. In this viewIn this view, both spools are , both spools are in the HOLD in the HOLD (or(or center) position.

center) position. Oil from the larOil from the large pump section enters ge pump section enters the valve andthe valve and starts to fill the chamber in the center of the valve body

starts to fill the chamber in the center of the valve body. . Flow from theFlow from the small section of the pump enters the valve body, flows around the small section of the pump enters the valve body, flows around the open-center tilt spool, and joins with the oil from the large section in the open-center center tilt spool, and joins with the oil from the large section in the center chamber.

chamber. All the oil around All the oil around the closed-center lift spool is blocked.the closed-center lift spool is blocked.

Because both spools are in the HOLD position, no oil flows to or from the Because both spools are in the HOLD position, no oil flows to or from the lift and tilt cylinders, and the load check valves cannot open.

lift and tilt cylinders, and the load check valves cannot open.

. .

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•

• DuDump mp vavalvelve The spring for the dump valve plus the pressure of the oil in the tank haveThe spring for the dump valve plus the pressure of the oil in the tank have a combined force that

a combined force that provides a restriction to flowprovides a restriction to flow. . When the pressure inWhen the pressure in the center chamber increases above the spring force plus the tank oil

the center chamber increases above the spring force plus the tank oil pressure, the dump valve will open and permit the combined flow from pressure, the dump valve will open and permit the combined flow from the two sections of the pump to

the two sections of the pump to return to the tank. return to the tank. With both spools in theWith both spools in the HOLD position, the dump valve provides a constant low system pressure HOLD position, the dump valve provides a constant low system pressure which is available for instant implement response or for "feathering" which is available for instant implement response or for "feathering" action of the controls when activated by the operator.

action of the controls when activated by the operator.

The shuttle valve resolves which hydraulic function (dozer raise and The shuttle valve resolves which hydraulic function (dozer raise and lower or ripper) will provide pressure feedback to the spring chamber of lower or ripper) will provide pressure feedback to the spring chamber of the dump valve.

the dump valve. The shuttle valve is spring The shuttle valve is spring biased to the dozer biased to the dozer lift andlift and lower function.

lower function. The stem shifts to The stem shifts to the right when oil the right when oil pressure is directedpressure is directed to the ripper valve port when the ripper function is requested by the to the ripper valve port when the ripper function is requested by the operator or during

operator or during an engine overspeed an engine overspeed condition. condition. When the When the lift spool islift spool is in the hold or center position, the spring chamber of the dump valve is in the hold or center position, the spring chamber of the dump valve is connected to the tank.

connected to the tank. TTank pressure is transmitted through passages inank pressure is transmitted through passages in the lift and lower spool that travel through the ball resolver valve and the the lift and lower spool that travel through the ball resolver valve and the shuttle valve before filling the spring chamber

shuttle valve before filling the spring chamber of the dump of the dump valve. valve. DuringDuring blade lift and lower functions, the cylinder load pressure signal is

blade lift and lower functions, the cylinder load pressure signal is transmitted to the ball resolver valve, through the shuttle valve, to the transmitted to the ball resolver valve, through the shuttle valve, to the spring chamber of the

spring chamber of the dump valve. dump valve. This path is the This path is the same as when same as when thethe spool is in the

spool is in the HOLD position. HOLD position. The cylinder load pressure signal is The cylinder load pressure signal is fromfrom the lift cylinder rod end during lift and from the cylinder head end during the lift cylinder rod end during lift and from the cylinder head end during lower or float.

lower or float. The ball resolver valve directs the The ball resolver valve directs the higher of either thehigher of either the cylinder rod or head end pressure to the shuttle valve.

cylinder rod or head end pressure to the shuttle valve.

Because the shuttle valve spool is moved completely to the left, pressure Because the shuttle valve spool is moved completely to the left, pressure oil from the center chamber cannot fill the spring chamber of the dump oil from the center chamber cannot fill the spring chamber of the dump valve.

valve. For this reason, only the For this reason, only the dump valve springs plus dump valve springs plus the tank oilthe tank oil pressure are regulating the pressure in

pressure are regulating the pressure in the center chamberthe center chamber. . This pressureThis pressure will remain low as long as the lift and tilt spools are in the HOLD

will remain low as long as the lift and tilt spools are in the HOLD position, and the ripper circuits are not activated.

position, and the ripper circuits are not activated.

•

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9

•

• DoDozezer RAr RAISEISE

FROM LARGE PUMP FROM LARGE PUMP LIFT RELIEF

LIFT RELIEF VALVE VALVE

DOZER LIFT SPOOL

RAISE RAISE

LIFT SPOOL LIFT SPOOL

This view of the dozer control valve shows spool movement and oil flow This view of the dozer control valve shows spool movement and oil flow when the control lever is

when the control lever is moved to the moved to the RAISE position. RAISE position. Movement of theMovement of the dozer lift spool to the RAISE position opens the chamber at the left center dozer lift spool to the RAISE position opens the chamber at the left center of the spool, which

of the spool, which is connected to the is connected to the rod end of rod end of the lift cylinders. the lift cylinders. SinceSince the oil around the lift spool is no longer blocked, pressure oil from the the oil around the lift spool is no longer blocked, pressure oil from the center chamber of the valve body can open the load check valve and flow center chamber of the valve body can open the load check valve and flow around the lift spool to the rod end of the lift cylinders.

around the lift spool to the rod end of the lift cylinders.

At the same time that pressure oil is sent to the lift cylinders, oil also At the same time that pressure oil is sent to the lift cylinders, oil also flows to the

flows to the ball resolver valve. ball resolver valve. The ball The ball resolver valve operates similarlyresolver valve operates similarly to a check

to a check valve. valve. With the With the lift spool in the lift spool in the RAISE position, the ballRAISE position, the ball resolver valve permits pressure oil to flow to the shuttle valve, but blocks resolver valve permits pressure oil to flow to the shuttle valve, but blocks flow to the drain passage at the right end of the ball resolver valve.

flow to the drain passage at the right end of the ball resolver valve.

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•

• DumDump valve conp valve conververtedted

to pilot operated relief

valve

During blade RAISE, the lift cylinder rod end pressure is transmitted to During blade RAISE, the lift cylinder rod end pressure is transmitted to the spring chamber of the dump valve through the ball resolver and the the spring chamber of the dump valve through the ball resolver and the shuttle valve.

shuttle valve. The dump The dump valve uses the valve uses the rod end rod end cylinder pressurecylinder pressure combined with the spring to move the dump valve to the right until the combined with the spring to move the dump valve to the right until the supply pressure is 700

supply pressure is 700 kPa (100 psi) above kPa (100 psi) above the cylinder pressure. the cylinder pressure. If theIf the pressure in the dump valve spring chamber reaches 22750 kPa (3300 psi) pressure in the dump valve spring chamber reaches 22750 kPa (3300 psi) due to cylinder load or an end stroke condition, the relief valve will open due to cylinder load or an end stroke condition, the relief valve will open and allow spring chamber

and allow spring chamber oil to drain to oil to drain to the tank. the tank. When oil is allowed When oil is allowed toto drain from the dump valve spring chamber, the dump valve moves to the drain from the dump valve spring chamber, the dump valve moves to the left and allows pump flow to pass around the dump valve to the tank. left and allows pump flow to pass around the dump valve to the tank. This operation prevents the system pressure from exceeding 22750 kPa This operation prevents the system pressure from exceeding 22750 kPa (3300 psi) during blade RAISE or LOWER.

(3300 psi) during blade RAISE or LOWER.

An additional condition can exist during dozer operation which is referred An additional condition can exist during dozer operation which is referred to as "feathering the blade."

to as "feathering the blade." If the operator moves If the operator moves the control lever athe control lever a small distance to gradually raise the blade, flow to the cylinders goes small distance to gradually raise the blade, flow to the cylinders goes through the throttling slots

through the throttling slots in the in the lift spool. lift spool. Flow through the Flow through the throttlingthrottling slots can create the same effect as an orifice by restricting the flow of oil slots can create the same effect as an orifice by restricting the flow of oil to the lift cylinder and

to the lift cylinder and and to the and to the spring chamber of the spring chamber of the dump valve. dump valve. ThisThis restriction to flow causes a pressure difference between the oil in the restriction to flow causes a pressure difference between the oil in the center chamber of the valve body (system pressure) and the oil in the center chamber of the valve body (system pressure) and the oil in the spring chamber of

spring chamber of the dump the dump valve (cylinder pressure). valve (cylinder pressure). If the pressureIf the pressure difference is greater than the spring force, the dump valve will open and difference is greater than the spring force, the dump valve will open and permit some of the pump flow to return to the tank.

permit some of the pump flow to return to the tank.

With the lift spool in the RAISE position, the load check valve is used to With the lift spool in the RAISE position, the load check valve is used to prevent reverse oil flow from the cylinders which can cause "cylinder prevent reverse oil flow from the cylinders which can cause "cylinder drift."

drift."

When the lift spool is held in the FLOAT position by the detents on the When the lift spool is held in the FLOAT position by the detents on the end of the

end of the spool, the load check spool, the load check valve is open. valve is open. The supply oil in The supply oil in thethe

center chamber goes through the open load check valve to the head end of center chamber goes through the open load check valve to the head end of the lift

the lift cylinders. cylinders. The center The center chamber is chamber is also open also open to the to the tank. tank. TheThe weight of the blade

weight of the blade is the force that is the force that moves the dozer down. moves the dozer down. The oil fromThe oil from the rod end of the lift cylinders is also open to the tank when the lift spool the rod end of the lift cylinders is also open to the tank when the lift spool is in the FLOA

is in the FLOAT position. T position. When an outside force moves the blade up, theWhen an outside force moves the blade up, the pressure of the oil in the rod end of the lift cylinders decreases as the rods pressure of the oil in the rod end of the lift cylinders decreases as the rods retract.

retract. The pressure of the The pressure of the oil in the rod oil in the rod end circuit is less than end circuit is less than thethe pressure in the head

pressure in the head end circuit. end circuit. The higher pressure in The higher pressure in the head endthe head end circuit opens a makeup valve to fill the rod end circuit as needed. circuit opens a makeup valve to fill the rod end circuit as needed.

The dozer control lever must be moved from the FLOAT position to move The dozer control lever must be moved from the FLOAT position to move the lift spool in the dozer control valve from the FLOAT position.

the lift spool in the dozer control valve from the FLOAT position.

•

• BladBlade "feate "featherheringing""

•

• LoaLoad chd check veck valvalvee

prevents drift

•

(17)

10

•

• DumDump valvp valve has fe has fourour

functions: functions: 1. 1. ReRelealease pse pumump flp flowow with levers in with levers in HOLD HOLD 2. 2. PrPresessusurree compensation compensation

valve for pump

ROD END LIFT CYLINDER ROD END LIFT CYLINDER HEAD END LIFT CYLINDER HEAD END LIFT CYLINDER

DOZER CONTROL VALVE DOZER CONTROL VALVE

HOLD HOLD ROD END ROD END TILT CYLINDER TILT CYLINDER HEAD END HEAD END TILT CYLINDER TILT CYLINDER LIFT SPOOL LIFT SPOOL LIFT RELIEF LIFT RELIEF VALVE VALVE TILT SPOOL TILT SPOOL DUMP DUMP VALVE VALVE

The dump valve in the dozer control valve has four different functions in The dump valve in the dozer control valve has four different functions in the dozer lift and ripper circuits.

the dozer lift and ripper circuits.

When the blade lift and ripper control spools are in the HOLD position, When the blade lift and ripper control spools are in the HOLD position, the pressure in the spring chamber of the dump valve is the same as tank the pressure in the spring chamber of the dump valve is the same as tank pressure plus 700 kPa

pressure plus 700 kPa (100 psi), which is the (100 psi), which is the value of the value of the spring. spring. DuringDuring blade RAISE or LOWER, the pressure in the spring chamber of the dump blade RAISE or LOWER, the pressure in the spring chamber of the dump valve is the same as the pressure in either the head end or rod end of the valve is the same as the pressure in either the head end or rod end of the lift cylinders.

lift cylinders. This pressure is This pressure is felt through the felt through the ball resolver valve ball resolver valve and theand the shuttle valve.

shuttle valve. With the With the cylinder pressure plus the spring force cylinder pressure plus the spring force behind thebehind the dump valve, the supply pressure will be raised to a level of 700 kPa dump valve, the supply pressure will be raised to a level of 700 kPa (100 psi) above

(100 psi) above the cylinder pressure. the cylinder pressure. Flow control and Flow control and fine modulationfine modulation are possible because of the constant 700 kPa (100 psi) pressure behind the are possible because of the constant 700 kPa (100 psi) pressure behind the dump valve.

dump valve.



(18)

3.

3. FlFlow cow conontrtrolol

4.

4. ReRelielief vf valvalve fe foror

main system

operation

When the ripper control spools are activated, pilot oil is sent to the right When the ripper control spools are activated, pilot oil is sent to the right end of the s

end of the shuttle valvhuttle valve and move and movesesthe shuttlthe shuttle valve to the valve to the left. e left. When theWhen the shuttle valve is moved, supply oil fills the spring chamber behind the shuttle valve is moved, supply oil fills the spring chamber behind the dump valve.

dump valve. The pilot valve and The pilot valve and the dump valve the dump valve now function as thenow function as the relief valve for the ripper

relief valve for the ripper circuit. circuit. Because oil from the Because oil from the drive end pumpdrive end pump section goes to both a passage in the dozer control valve and to the ripper section goes to both a passage in the dozer control valve and to the ripper control valve, the pressure of the oil is always the same in both places. control valve, the pressure of the oil is always the same in both places. When the lift spool is in the RAISE or LOWER position, cylinder When the lift spool is in the RAISE or LOWER position, cylinder

pressure is transmitted to the spring chamber of the dump valve through pressure is transmitted to the spring chamber of the dump valve through the ball resolver valve and

the ball resolver valve and the shuttle valve. the shuttle valve. A pressure relief valve isA pressure relief valve is located within the dump

located within the dump valve spring chambervalve spring chamber. . This valve will lift ofThis valve will lift off itsf its seat and allow the spring chamber oil to drain when the pressure in the seat and allow the spring chamber oil to drain when the pressure in the spring chamber reaches

spring chamber reaches 22750 kPa 22750 kPa (3300 psi). (3300 psi). When the relief When the relief valvevalve opens, an imbalance exists between the pressure in the center chamber opens, an imbalance exists between the pressure in the center chamber and a combination of the dump valve spring and the pressure in the spring and a combination of the dump valve spring and the pressure in the spring chamber.

chamber. A balance is achieved when the dump A balance is achieved when the dump valve shifts to the leftvalve shifts to the left allowing oil in the center chamber to drain until the pressure in the center allowing oil in the center chamber to drain until the pressure in the center chamber is equal to the dump valve spring plus the spring chamber

chamber is equal to the dump valve spring plus the spring chamber pressure.

pressure. This method This method of controlling maximum of controlling maximum system pressure is system pressure is calledcalled a pilot operated relief valve.

(19)

11

•

• QuicQuick-dk-drop varop valve inlve in

RAISE position RAISE position

QUICK-DROP VALVE

RAISE RAISE

ROD END OIL ROD END OIL

HEAD END OIL HEAD END OIL

Quick-drop Valves

All flow to and from the lift cylinders must go through the quick-drop All flow to and from the lift cylinders must go through the quick-drop valves that are installed on top

valves that are installed on top of each cylinderof each cylinder. . The primary function of The primary function of the quick-drop valve is to allow rapid blade lower without voiding the the quick-drop valve is to allow rapid blade lower without voiding the head end

head end of the of the lift cylinders. lift cylinders. Minimizing the amount Minimizing the amount of cylinder voidingof cylinder voiding reduces the time delay that will occur when a rapid blade lower is

reduces the time delay that will occur when a rapid blade lower is followed by an

followed by an operator request for operator request for blade down pressure. blade down pressure. The quick-dropThe quick-drop valve is activated when a sufficient pressure difference occurs between the valve is activated when a sufficient pressure difference occurs between the cylinder rod end oil

cylinder rod end oil and the oil in and the oil in the spring cavitythe spring cavity. . This pressureThis pressure difference is caused by rod end oil flow through an orfice in the difference is caused by rod end oil flow through an orfice in the quick-drop valve.

drop valve. The quick-drop valve is de-activated by The quick-drop valve is de-activated by high pressure in thehigh pressure in the head end felt through

head end felt through a slot in a slot in the spool. the spool. The quick-drop valves help toThe quick-drop valves help to control four functions of

control four functions of the bulldozer: the bulldozer: RAISE, LOWER RAISE, LOWER at slow speeds,at slow speeds, rapid LOWER, and LOWER with down pressure.

rapid LOWER, and LOWER with down pressure.



(20)

When the dozer control lever is moved to the RAISE position, supply oil When the dozer control lever is moved to the RAISE position, supply oil enters the quick-drop valve through an inlet and an orifice, flows through enters the quick-drop valve through an inlet and an orifice, flows through a sleeve, and is directed to the rod end

a sleeve, and is directed to the rod end of the lift cylinder. of the lift cylinder. A smallA small amount of oil passes through another orifice and fills the spring chamber amount of oil passes through another orifice and fills the spring chamber behind the plunger.

behind the plunger. The pressure of this oil adds to the force of The pressure of this oil adds to the force of thethe spring, which pushes

spring, which pushes the valve against the valve against the sleeve. the sleeve. This condition causesThis condition causes all the oil entering the quick-drop valve to be directed to the rod end of all the oil entering the quick-drop valve to be directed to the rod end of the lift cylinders and all the oil from the head end of the lift cylinders to the lift cylinders and all the oil from the head end of the lift cylinders to return to the tank.

(21)

12

•

• QuicQuick-dk-drop varop valve inlve in

LOWER LOWER

QUICK-DROP VALVE

LOWER

When the dozer control lever is at less than approximately 75% of full When the dozer control lever is at less than approximately 75% of full lever travel, the lowering

lever travel, the lowering of the of the blade is controlled or blade is controlled or modulated. modulated. SinceSince the control lever is directly connected to the dozer control valve lift spool, the control lever is directly connected to the dozer control valve lift spool, the spool movement is

the spool movement is proportional to the lever movement. proportional to the lever movement. The flow of The flow of oil that can pass through the control valve lift spool at any given position oil that can pass through the control valve lift spool at any given position is a function of the pressure difference across the spool and the

is a function of the pressure difference across the spool and the temperature of the

temperature of the oil. oil. As mentioned earlierAs mentioned earlier, the quick-drop , the quick-drop valve isvalve is activated by high lift cylinder rod end oil flow in combination with low activated by high lift cylinder rod end oil flow in combination with low lift cylinder head end

lift cylinder head end pressure. pressure. For this reason, For this reason, the actual control the actual control leverlever position when the quick-drop valve is actuated can vary based on oil position when the quick-drop valve is actuated can vary based on oil temperature and the blade weight, which determines the rod end oil temperature and the blade weight, which determines the rod end oil pressure.

pressure.



(22)

When the dozer control lever is moved to the LOWER position, supply When the dozer control lever is moved to the LOWER position, supply oil enters the quick-drop valve through a port and flows to the head end of oil enters the quick-drop valve through a port and flows to the head end of the lift cylinders.

the lift cylinders. The oil being The oil being pushed from the rod pushed from the rod end of the end of the cylinderscylinders returns through the control valve to

returns through the control valve to the tank. the tank. Because of the wBecause of the weight of theeight of the blade and the resistance to flow, the pressure of the rod end oil may be blade and the resistance to flow, the pressure of the rod end oil may be higher than the head

higher than the head end oil. end oil. The flow of The flow of oil through the orifice is oil through the orifice is notnot high enough to create a large pressure difference between the oil in the high enough to create a large pressure difference between the oil in the port and the

port and the oil behind the plungeroil behind the plunger. . The spring holds the The spring holds the valve against thevalve against the sleeve and all the oil leaving the rod end of the lift cylinder returns

sleeve and all the oil leaving the rod end of the lift cylinder returns through the control valve to the hydraulic tank.

(23)

13

•

• QuicQuick-dk-drop LOWrop LOWERER

QUICK-DROP VALVE

QUICK-DROP

When the dozer control lever exceeds approximately 75% of lever travel When the dozer control lever exceeds approximately 75% of lever travel and the cylinder head end pressure is low, the quick-drop valve is

and the cylinder head end pressure is low, the quick-drop valve is activated and the blade drops very rapidly.

activated and the blade drops very rapidly.

The oil flow for a quick drop is the same as slow lower except that some The oil flow for a quick drop is the same as slow lower except that some of the oil leaving the rod end of the lift cylinder is directed into the head of the oil leaving the rod end of the lift cylinder is directed into the head end of the

end of the cylinder. cylinder. When the flow of When the flow of oil through the orifice createsoil through the orifice creates enough pressure differential between the port and the plunger spring enough pressure differential between the port and the plunger spring chamber, the valve and plunger shift to the left and permit oil leaving the chamber, the valve and plunger shift to the left and permit oil leaving the rod end to be added to the supply oil filling the head end of the lift

rod end to be added to the supply oil filling the head end of the lift cylinders.

cylinders. As mentioned earlier, As mentioned earlier, during a rapid blade during a rapid blade drop, the rod enddrop, the rod end pressure will be higher than

pressure will be higher than the head end the head end due to the due to the blade weight. blade weight. TheThe resulting pressure differential and valve movement allow the rod end oil resulting pressure differential and valve movement allow the rod end oil to flow to the head end of the cylinder and minimize cylinder voiding. to flow to the head end of the cylinder and minimize cylinder voiding.

(24)

14

•

• LOWLOWER wER with ith dowdownn

pressure

QUICK-DROP VALVE

LOWER WITH DOWN PRESSURE LOWER WITH DOWN PRESSURE

When down pressure must be applied to the blade, the operator moves the When down pressure must be applied to the blade, the operator moves the dozer control lever to the

dozer control lever to the LOWER position. LOWER position. Pressure oil from the dozerPressure oil from the dozer control valve is sent to

control valve is sent to the head end the head end of the lift cylinders. of the lift cylinders. At the sameAt the same time, oil fills the chamber at

time, oil fills the chamber at the left end of the left end of valve spool. valve spool. As the head As the head endend pressure and resistance to downward movement increase, pressure in the pressure and resistance to downward movement increase, pressure in the chamber at the left end of the valve spool moves the plunger to the left chamber at the left end of the valve spool moves the plunger to the left against the force of the spring and moves the valve spool completely to against the force of the spring and moves the valve spool completely to the right.

the right. All the pressure oil All the pressure oil from the dozer control valve from the dozer control valve is then sent tois then sent to the head end

the head end of the lift cylinders. of the lift cylinders. All the rod All the rod end oil is returned throughend oil is returned through the dozer control valve to the tank.

(25)

15

•

• Fan pFan pumpumps pars part oft of

hydraulic system

•

• DemDemand coand contrntrol fanol fan

system equipped with

tandem axial pumps

FAN FAN PUMPS PUMPS SOLENOID SOLENOID TANK TANK FAN DRIVE FAN DRIVE MOTOR MOTOR RADIATOR RADIATOR OIL COOLER OIL COOLER OIL OIL COOLER COOLER BYPASS BYPASS VALVE VALVE FAN DRIVE FAN DRIVE HYDRAULIC SYSTEM HYDRAULIC SYSTEM TO PILOT VALVES TO PILOT VALVES

Fan Drive Hydraulic System

The demand control fan system on the D11R is considered part of the The demand control fan system on the D11R is considered part of the implement hydraulic system because the fan pumps pull oil from the implement hydraulic system because the fan pumps pull oil from the implement hydraulic tank and send some of the oil to the pilot control implement hydraulic tank and send some of the oil to the pilot control valves.

valves. Pilot oil shifts the blade Pilot oil shifts the blade tilt spool in the tilt spool in the dozer control valve anddozer control valve and also shifts the spools in the ripper control valve to control ripper lift and also shifts the spools in the ripper control valve to control ripper lift and ripper tip.

ripper tip.

The tractor is equipped with two hydraulic pumps for the demand control The tractor is equipped with two hydraulic pumps for the demand control fan system.

fan system. The tandem The tandem axial (variable displacement) pumps are axial (variable displacement) pumps are locatedlocated on the right rear side of the engine and

on the right rear side of the engine and are driven off the flywheel. are driven off the flywheel. TheThe system adjusts the fan speed to match the cooling system demands based system adjusts the fan speed to match the cooling system demands based on an input signal to the engine Electronic Control Module (ECM) from on an input signal to the engine Electronic Control Module (ECM) from the engine coolant temperature sensor.

(26)

•

• Ripper Ripper contrcontrol ol valvevalve

(arrow)

16

Ripper and Pilot Circuits

The ripper control valve (arrow) has two spools (lift and tip), two makeup The ripper control valve (arrow) has two spools (lift and tip), two makeup valves (one for the head end of the ripper lift cylinders and one for the valves (one for the head end of the ripper lift cylinders and one for the head end of

head end of the ripper tip cylinders), and a the ripper tip cylinders), and a load check valve. load check valve. The ripperThe ripper lift spool

lift spoolis operated with pilois operated with pilot oil pressure and has three positiot oil pressure and has three positions:ns: RAISE, HOLD, and

RAISE, HOLD, and LOWER. LOWER. The ripper tip spool The ripper tip spool is operated by pilotis operated by pilot pressure oil and also

pressure oil and also has three positions: has three positions: SHANK IN, HOLD, SHANK IN, HOLD, andand SHANK OUT

SHANK OUT. . The valve spools have The valve spools have no detent positions.no detent positions.

Movement of the ripper control lever to the left causes the ripper to lift Movement of the ripper control lever to the left causes the ripper to lift and movement to

and movement to the right causes the the right causes the ripper to lowerripper to lower. . When the ripperWhen the ripper control lever is moved forward, the ripper tip moves toward the machine control lever is moved forward, the ripper tip moves toward the machine (SHANK IN).

(SHANK IN). Pulling the ripper control lever toward Pulling the ripper control lever toward the rear causes thethe rear causes the ripper tip to move away from the machine (SHANK OUT).

(27)

17

•

• RipRippeper RAIr RAISESE

RIPPER TIP RIPPER TIP SPOOL SPOOL RIPPER LIFT RIPPER LIFT SPOOL SPOOL LIFT LIFT CYLINDERS CYLINDERS MAKEUP VALVE MAKEUP VALVE FOR HEAD END FOR HEAD END

OF LIFT OF LIFT CYLINDERS

CYLINDERS LOADLOAD

CHECK CHECK VALVE VALVE RIPPER RIPPER

AND PILOT SYSTEMS AND PILOT SYSTEMS

RAISE RAISE FROM FROM FAN PUMP FAN PUMP TO DOZER TO DOZER CONTROL VALVE CONTROL VALVE TO SHUTTLE TO SHUTTLE VALVE VALVE

When the ripper control lever is moved to the RAISE position, pilot oil is When the ripper control lever is moved to the RAISE position, pilot oil is directed to the upper end

directed to the upper end of the lift spool of the lift spool and moves the and moves the spool down. spool down. TheThe supply oil opens the load check valve, goes around the lift spool, and supply oil opens the load check valve, goes around the lift spool, and flows to the rod end of the ripper lift cylinders, causing the cylinder rods flows to the rod end of the ripper lift cylinders, causing the cylinder rods to retract and the ripper to raise.

to retract and the ripper to raise.

The oil that is forced from the head end of the ripper lift cylinders flows The oil that is forced from the head end of the ripper lift cylinders flows through the ripper control valve, around the lift spool, and returns to the through the ripper control valve, around the lift spool, and returns to the tank.

tank.

When the ripper control lever is released, the pilot oil in the upper spring When the ripper control lever is released, the pilot oil in the upper spring chamber is drained.

chamber is drained. The lower spring returns The lower spring returns the ripper lift spool to the ripper lift spool to thethe HOLD position.

HOLD position. The oil is blocked The oil is blocked and holds the and holds the ripper in position untilripper in position until the ripper control lever is moved again.

(28)

18

•

• MakMakeup eup valvalveve

LIFT LIFT CYLINDERS CYLINDERS LOAD LOAD CHECK CHECK VALVE VALVE RIPPER TIP RIPPER TIP SPOOL SPOOL RIPPER LIFT RIPPER LIFT SPOOL SPOOL MAKEUP VALVE MAKEUP VALVE FOR HEAD END FOR HEAD END

OF LIFT OF LIFT CYLINDERS CYLINDERS RIPPER RIPPER

LOWER LOWER FROM FROM FAN PUMP FAN PUMP TO DOZER TO DOZER CONTROL VALVE CONTROL VALVE TO SHUTTLE TO SHUTTLE VALVE VALVE

The makeup valve operates

The makeup valve operates when the ripper is when the ripper is lowered quickly. lowered quickly. When theWhen the lift spool is in the LOWER position, supply pressure oil is in the head end lift spool is in the LOWER position, supply pressure oil is in the head end of the ripper lift cylinders and oil is returning from the rod end of the of the ripper lift cylinders and oil is returning from the rod end of the cylinders to the tank.

cylinders to the tank.

If the cylinder head end supply pressure becomes less than the tank If the cylinder head end supply pressure becomes less than the tank

pressure due to the weight of the ripper, the makeup valve opens to let the pressure due to the weight of the ripper, the makeup valve opens to let the tank oil add to

tank oil add to the supply oil. the supply oil. This condition prevents cavitation in theThis condition prevents cavitation in the head end of the lift cylinders and prevents delays in the operation of the head end of the lift cylinders and prevents delays in the operation of the ripper.

(29)

19

•

• LoaLoad chd check veck valvalvee

RIPPER TIP RIPPER TIP SPOOL SPOOL RIPPER LIFT RIPPER LIFT SPOOL SPOOL LIFT LIFT CYLINDERS CYLINDERS MAKEUP VALVE MAKEUP VALVE FOR HEAD END FOR HEAD END

CYLINDERS LOADLOAD

The load check valve prevents reverse oil flow from the ripper cylinders. The load check valve prevents reverse oil flow from the ripper cylinders. For example, when the ripper lift spool is in RAISE position, supply oil For example, when the ripper lift spool is in RAISE position, supply oil opens the load check valve and flows to the rod end of the lift cylinders. opens the load check valve and flows to the rod end of the lift cylinders. If the pressure of the pump oil decreases, the force of the spring in the If the pressure of the pump oil decreases, the force of the spring in the load check valve will close the load check valve and hold the oil in the rod load check valve will close the load check valve and hold the oil in the rod end of the

end of the lift cylinders. lift cylinders. This condition prevents any movement This condition prevents any movement of theof the ripper lift cylinders and will not let the ripper drop.

(30)

20 20 • • SHSHANANK IK INN TIP TIP CYLINDERS

CYLINDERS _{RIPPER TIP}_{RIPPER TIP} SPOOL SPOOL RIPPER LIFT RIPPER LIFT SPOOL SPOOL MAKEUP VALVE MAKEUP VALVE FOR HEAD END FOR HEAD END

CYLINDERS LOADLOAD

SHANK IN SHANK IN FROM FROM FAN PUMP FAN PUMP TO DOZER TO DOZER CONTROL VALVE CONTROL VALVE

When the ripper control lever is moved to the SHANK IN position, pilot When the ripper control lever is moved to the SHANK IN position, pilot oil is directed through the ripper control valve to the upper end of the oil is directed through the ripper control valve to the upper end of the ripper tip spool.

ripper tip spool. The pressure of the The pressure of the pilot oil moves the pilot oil moves the ripper tip spoolripper tip spool down.

down. The pump oil The pump oil opens the load check opens the load check valve and goes around valve and goes around the liftthe lift and tip spools to the head end of the ripper tip cylinders, causing the rods and tip spools to the head end of the ripper tip cylinders, causing the rods to extend and move the ripper tip toward the machine.

to extend and move the ripper tip toward the machine.

The oil that is pushed from the rod end of the ripper tip cylinders flows The oil that is pushed from the rod end of the ripper tip cylinders flows through the ripper control valve and returns to the tank

(31)

21

•

• PiloPilot contt control varol valveslves

•

• DumDump valp valve acve acts asts as

ripper circuit relief

valve valve RIPPER TIP RIPPER TIP SPOOL SPOOL RIPPER LIFT RIPPER LIFT SPOOL SPOOL LIFT LIFT CYLINDERS CYLINDERS MAKEUP VALVE MAKEUP VALVE FOR HEAD END FOR HEAD END

CYLINDERS LOADLOAD

Three pilot valves are located below the dozer and ripper control levers to Three pilot valves are located below the dozer and ripper control levers to the right of the

the right of the operator. operator. The closed-center pilot valves control the dozerThe closed-center pilot valves control the dozer tilt, ripper lift, and

tilt, ripper lift, and ripper tip functions. ripper tip functions. No oil No oil flows through the flows through the pilotpilot valves when the spools

valves when the spools are in the Hare in the HOLD position. OLD position. Each valve is Each valve is centeredcentered by springs.

by springs.

When the ripper circuit is activated by the operator, pilot oil from the fan When the ripper circuit is activated by the operator, pilot oil from the fan pump flows through the pilot valve to one end of the lift spool or tip pump flows through the pilot valve to one end of the lift spool or tip spool.

spool. At the same At the same time, pilot oil flows to time, pilot oil flows to the shuttle valve in the shuttle valve in the dozerthe dozer control valve.

control valve. The shuttle valve shifts to The shuttle valve shifts to the right and allows the right and allows oil to flowoil to flow to the spring chamber of the dump valve which now functions as the relief to the spring chamber of the dump valve which now functions as the relief valve for the ripper circuit.

valve for the ripper circuit. When the shuttle valve is When the shuttle valve is shifted, the oil fromshifted, the oil from both the small and large pumps is directed to the load check valve in the both the small and large pumps is directed to the load check valve in the ripper control valve.

(32)

22 22 • • TITILT LT RIGRIGHTHT

PILOT SYSTEM

BLADE TILT RIGHT BLADE TILT RIGHT

FROM FROM FAN PUMP FAN PUMP RIGHT TILT RIGHT TILT CYLINDER CYLINDER

FROM LARGE PUMP FROM LARGE PUMP

The tilt circuit receives oil from

The tilt circuit receives oil from the small section of the small section of the pump. the pump. When theWhen the circuit is not in use, this oil combines with the oil from the large section of circuit is not in use, this oil combines with the oil from the large section of the pump for

the pump for the lift circuit. the lift circuit. The tilt valve spool The tilt valve spool has three positions:has three positions: TILT RIGHT, HOLD and TILT LEFT.

TILT RIGHT, HOLD and TILT LEFT.

The tilt valve spool is hydraulically operated by pilot oil pressure from the The tilt valve spool is hydraulically operated by pilot oil pressure from the pilot valve that is controlled by

pilot valve that is controlled by the dozer control leverthe dozer control lever. . When the dozerWhen the dozer control lever is moved to the TILT RIGHT position, the linkage moves the control lever is moved to the TILT RIGHT position, the linkage moves the pilot spool down.

pilot spool down. This movement allows pilot oil This movement allows pilot oil to flow to to flow to the left endthe left end of the tilt spool in

of the tilt spool in the dozer control valve. the dozer control valve. Pilot pressure at the left Pilot pressure at the left end of end of the tilt spool moves the spool to the right and permits oil from the small the tilt spool moves the spool to the right and permits oil from the small section of the pump to flow to the

section of the pump to flow to the rod end of the tilt cylinderrod end of the tilt cylinder. . As the rodAs the rod end pressure increases, the rod retracts and

end pressure increases, the rod retracts and tilts the blade to tilts the blade to the right. the right. OilOil from the head end of the tilt cylinder is returned through the dozer control from the head end of the tilt cylinder is returned through the dozer control valve to the tank.

(33)

23

•

• DuaDual tilt l tilt valvalve have hass

three modes:

-- DuDual tal tililtt

-- SinSinglgle te tiltilt

-- BlaBlade pde pititchch

•

• SoleSolenoinoid vd valvalvee

contains two

positioning coils

•

• TriTriggegger sr switcwitchh

activates S1 coil

•

• TogToggle gle switswitchch

activates S2 coil activates S2 coil S1 S1 S2 S2

DUAL TILT VALVE

TILT TILT CYLINDERS CYLINDERS

PILOT OIL FROM PILOT OIL FROM

FAN PUMP FAN PUMP FROM BLADE FROM BLADE TILT VALVE TILT VALVE HOLD HOLD TO HEAD END TO HEAD END TO ROD END TO ROD END

Dual Tilt Valve

The dual tilt attachment provides the blade tilt circuit with three different The dual tilt attachment provides the blade tilt circuit with three different modes of operation:

modes of operation: DUAL TILDUAL TILTT, SINGLE TIL, SINGLE TILTT, and BLADE PITCH., and BLADE PITCH. The control valve is located between the radiator grill doors and the The control valve is located between the radiator grill doors and the radiator on the left side

radiator on the left side of the machine. of the machine. The valve is The valve is activated by pilot oilactivated by pilot oil pressure from the

pressure from the solenoid valve. solenoid valve. The dual The dual tilt valve contains a tilt valve contains a springspring centered, hydraulically actuated spool valve and an electrically actuated centered, hydraulically actuated spool valve and an electrically actuated solenoid control valve.

solenoid control valve.

The solenoid valve contains two coils and has three different positions. The solenoid valve contains two coils and has three different positions. When neither solenoid is activated, the system operates in the DUAL When neither solenoid is activated, the system operates in the DUAL TIL

TILT mode. T mode. When the toggle switch on the dozer control lever is movedWhen the toggle switch on the dozer control lever is moved forward, the S2 coil in the solenoid valve is energized and the system forward, the S2 coil in the solenoid valve is energized and the system operates in the SINGLE TIL

operates in the SINGLE TILT mode. T mode. When the trigger switch on theWhen the trigger switch on the dozer control lever is depressed, the system energizes the S1 coil in the dozer control lever is depressed, the system energizes the S1 coil in the solenoid and activates the BLADE PITCH mode.

solenoid and activates the BLADE PITCH mode.

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• Tilt Tilt cylindecylinders rs contaicontainn

bypass valves

Both the

Both the left and right left and right tilt cylinders pistons contain bypass tilt cylinders pistons contain bypass valves. valves. TheseThese valves allow the completion of

valves allow the completion of the tilt operation. the tilt operation. When one of When one of thethe cylinders reaches the end of its travel, the oil goes through the bypass cylinders reaches the end of its travel, the oil goes through the bypass valve to continue filling the other cylinder.

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• DuaDual tilt opl tilt operaeratiotionn

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• DUADUAL TIL TILT LT RIGHRIGHTT

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• CyliCylindenders mors move inve in

opposite directions opposite directions FROM TILT FROM TILT CONTROL VALVE CONTROL VALVE TO TILT TO TILT CONTROL VALVE

CONTROL VALVE FROM FANFROM FAN

PUMP PUMP

FROM TRIGGER SWITCH FROM TRIGGER SWITCH FROM TOGGLE SWITCH FROM TOGGLE SWITCH LEFT TILT LEFT TILT CYLINDER CYLINDER RIGHT TILT RIGHT TILT CYLINDER CYLINDER TO HEAD END TO HEAD END TO ROD END TO ROD END

DUAL TILT CIRCUIT DUAL TILT CIRCUIT

DUAL TILT RIGHT DUAL TILT RIGHT

When the toggle switch on the dozer control lever is in the rear (OFF) When the toggle switch on the dozer control lever is in the rear (OFF) position and the trigger switch is not depressed, neither coil in the position and the trigger switch is not depressed, neither coil in the solenoid valve is energized.

solenoid valve is energized. The control valve is The control valve is operating in the DUALoperating in the DUAL TIL

TILT mode. T mode. In the DUAL TILIn the DUAL TILT mode, oil flow is blocked at the solenoidT mode, oil flow is blocked at the solenoid valve and the dual tilt directional spool remains centered by the spring valve and the dual tilt directional spool remains centered by the spring force.

force.

When the operator moves the dozer control lever to the TILT RIGHT When the operator moves the dozer control lever to the TILT RIGHT position, pump oil from the dozer control valve tilt circuit is sent to the position, pump oil from the dozer control valve tilt circuit is sent to the head end of

head end of the left tilt cylinderthe left tilt cylinder. . This condition causes oil from This condition causes oil from the rodthe rod end of the left tilt cylinder to be forced back to the dual tilt control valve. end of the left tilt cylinder to be forced back to the dual tilt control valve. The oil travels around the spool and is directed to the rod end of the right The oil travels around the spool and is directed to the rod end of the right tilt cylinder.

tilt cylinder. As the right tilt As the right tilt cylinder retracts, the oil in the cylinder retracts, the oil in the head end of head end of the cylinder is directed back through the dual tilt control valve and the the cylinder is directed back through the dual tilt control valve and the dozer tilt control valve to the

dozer tilt control valve to the tank. tank. Movement of the tilt cylinders inMovement of the tilt cylinders in opposite directions causes the blade to tilt.

opposite directions causes the blade to tilt.