TOOTH GP-UNI 9W1880 - Caterpillar

Illustration 1 g02025839
Line relief valve
(13) Inlet
(14) Tank passage
(15) Cavity
(16) Poppet
(17) Tank passage
(18) Spring
(19) Makeup spool
(20) Valve
(21) Dump spool
(22) Spring
(23) Cavity
(AA) Supply oil
(BB) Tank oil
(CC) Active components
(DD) Surface area Illustration 1 shows a line relief valve with the pressure at inlet (13) below the adjusted pressure of the valve.
Illustration 2 g02025858
Line relief valve
(13) Inlet
(14) Tank passage
(15) Cavity
(16) Poppet
(17) Tank passage
(18) Spring
(19) Makeup spool
(20) Valve
(21) Dump spool
(22) Spring
(23) Cavity
(AA) Supply oil
(BB) Tank oil
(CC) Active components
(DD) Surface area
(EE) Reduced supply pressure Illustration 2 shows a line relief valve with the pressure at inlet (13) that is starting to rise above the adjusted pressure of the valve. As the pressure begins to rise, the oil that is flowing into inlet (13) will shift valve (20) to the right. High-pressure oil flows past valve (20) into cavity (15). The oil pressure in cavity (15) works against the area of poppet (16). The force that is developed on the area around the end of poppet (16) overrides the force of spring (18). Poppet (16) shifts to the right.
Illustration 3 g02025875
Line relief valve
(13) Inlet
(14) Tank passage
(15) Cavity
(16) Poppet
(17) Tank passage
(18) Spring
(19) Makeup spool
(20) Valve
(21) Dump spool
(22) Spring
(23) Cavity
(AA) Supply oil
(BB) Tank oil
(CC) Active components
(DD) Surface area
(EE) Reduced supply pressure When poppet (16) shifts to the right, the pressure in cavity (15) will decrease. The pressure on the end of valve (20) overrides spring (22). Then, dump spool (21) moves toward the right. The flow of oil that is needed to lower the pressure at inlet (13) is allowed to flow out of tank passage (14).When the pressure at inlet (13) is less than the adjusted pressure, the force of spring (28) moves poppet (16) to the left. Poppet (16) will seat. Then, the combination of the pressure in cavity (15) and the spring force from spring (22) moves dump spool (21) left against the seat. At this time, the flow of oil to tank passage (14) is blocked.Makeup Valve
The line relief valve can be used as a makeup valve. When either the lift cylinder or the tilt cylinder is moving and the pump cannot supply the amount of oil that is needed to fill the