HOUSING 2299283 - Caterpillar

LOWER WITHOUT QUICK-DROP
Illustration 3 g03467562
Quick-Drop Valve (LOWER)
(1) Passage from control valve (head end)
(2) Passage from control valve (rod end)
(3) Orifice sleeve
(4) Spring
(5) Plunger
(6) Passage to left blade lift cylinder (rod end)
(7) Passage to left blade lift cylinder (head end)
(8) Passage to right blade lift cylinder (head end)
(9) Passage to right blade lift cylinder (rod end)
(10) Quick drop solenoid passage
(11) Left blade lift cylinder
(12) Right blade lift cylinder
(13) Bypass valve
(14) Quick drop solenoid
(15) Valve spool
(16) ECM
(17) Quick drop valve
(18) Stem
(BB) Cutaway Section
(CC) Component Surface
(FF) Activated Component
(GG) Tank Oil
(KK) High pressure
(LL) First Pressure Reduction When the blade control lever is moved less than 75 percent of the maximum travel in the LOWER position, reduced pump pressure enters the quick-drop valve through passage (1). This oil flows around valve spool (15) and through passage (7) and passage (8) to the head end of the cylinders.At the same time, the reduced pump pressure enters passage to the right side of plunger (5). This pressure causes plunger (5) to shift to the left. When plunger (5) reaches the stop, the pressure on the right side of plunger (5) is greater than the return to tank pressure on the right side of stem (18). This pressure forces stem (18) to shift to the right.Return oil from the rod end of the cylinders enters the quick-drop valve through passage (6) and passage (9). The return oil flows past orifice sleeve (3) to the blade lift control valve. The blade lowers. The return oil moves orifice sleeve (3) to the left against the retaining ring. This oil flow creates a pressure differential across the orifice sleeve.Return oil from the rod end of the cylinders enters the passage on the left end of valve spool (15). This pressure shifts valve spool (15) to the right because the pressure in passage (10) is return to tank. As a result, the spool and the plunger are kept to the right because of the spring and the pressure of the return oil.The return oil flows around valve spool (15) through passage (2) to the blade lift control valve. The blade lift control valve sends this oil through the charging valve to the hydraulic oil tank.LOWER WITH QUICK-DROP
Illustration 4 g03536120
Quick-Drop Valve (QUICK-DROP)
(1) Passage from Control Valve (Head End)
(2) Passage from Control Valve (Rod End)
(3) Orifice Sleeve
(4) Spring
(5) Plunger
(6) Passage to Left Blade Lift Cylinder (Rod End)
(7) Passage to Left Blade Lift Cylinder (Head End)
(8) Passage to Right Blade Lift Cylinder (Head End)
(9) Passage to Right Blade Lift Cylinder (Rod End)
(10) Quick Drop Solenoid Passage
(11) Left Blade Lift Cylinder
(12) Right Blade Lift Cylinder
(13) Bypass Valve
(14) Quick drop solenoid
(15) Valve spool
(16) ECM
(17) Quick drop valve
(18) Stem
(BB) Cutaway Section
(CC) Component Surface
(FF) Activated Component
(GG) Tank Oil
(KK) High pressure
(LL) First Pressure Reduction When the blade control lever is moved more than 75 percent of the maximum travel in the LOWER position, the quick-drop valve operates in the QUICK-DROP mode.The increased travel of the blade control lever results in higher oil flow from the rod end of the cylinders