Komatsu D32E-1 Shop Manual page 418

GENERAL
1. Hydraulic Reservoir
2. Suction Strainer
3. Gear Pump
4. Control Valve
5. System Relief Valve
DESCRIPTION
The hydraulic system consists of a reservoir (1), gear pump (3), control valve (4), piping, and cylinders (14, 15 and 16).
A ripper attachment is available and consists of an additional valve section (9), cylinders (17) and piping.
OPERATION
The hydraulic reservoir (1), mounted next to the fuel tank, supplies oil through a suction strainer (2) to the gear pump
(3). The pump is flange mounted at the left side of the torque converter and is driven by the converter accessory gear
whenever the engine is running. Oil from the pump is directed to the inlet section of the main control valve (4). When
the valve is not actuated, oil will flow back to the reservoir. The reservoir is bolted to a bracket mounted to the rear main
frame. It is equipped with a 100 mesh suction strainer (2), an external mounted return oil filter (18), incorporating a cold
oil bypass valve and an external vacuum pressure relief breather (19). The breather will protect the pump from cavitating
as well as maintaining pressure in the reservoir.
A positive displacement, single element, gear type pump (2) is used to supply pressurized fluid to the main control valve
(4). The pump operates continually while the engine is running, but is under load only when the main control valve
spool(s) is/are shifted from neutral. As oil is supplied to the pump, gear rotation forces oil to the outer diameter of the
housing between the teeth. As oil exits it is directed to the main control valve.
The main control valve (4) is mounted to a bracket in the right control console in front of the reservoir located on the
right fender. This system utilizes either a three or four spool valve depending on whether or not a ripper is used. The
valve is controlled by mechanical linkage between the control levers and the valve. Mechanical linkage controls the
blade and ripper, if equipped. The valve inlet cover contains an adjustable pilot operated main pressure relief valve (5)
which is used to by pass oil from the pump back to the reservoir when oil pressure exceeds the relief valve setting. The
spools are spring centered, either three or four position type with the FLOAT position being detented. Incorporated in
the valve section is a spring loaded check valve (10) which will assure smooth operation when the spool is moved from
hold to an operating position. An anti-cavitation valve (11) is located in the blade lift (6), blade angle (8), and ripper
section (9), if equipped, sections. A three spool control valve is used on machines equipped with a six way blade. A four
spool control valve is used on machines equipped with a six way blade and a ripper.
Six Way Blade: The first spool is used for the blade lift (6) and is a spring centered, four position type with FLOAT
position being detented. The middle spool (7) is used for blade tilt. The third spool is for blade angle (8). Both of the
spools are spring centered, three position type. Incorporated in each valve section is a spring loaded check valve (10)
which assures smooth operation when the spool is moved from hold to an operating position. An anti-cavitation valve
(11) is located in the blade lift and angle valve sections only.
Six Way Blade With Ripper: The first spool is used for the blade lift (6) and is a spring centered, four position type with
FLOAT position being detented. The middle spool (7) is used for the blade tilt. The third spool (8) is for the blade angle.
Both of the spools are spring centered, three position type. Incorporated in each valve section is a spring loaded check
valve (10) which assures smooth operation when the spool is moved from hold to an operating position. An anti-
cavitation valve (11) is located in the blade lift and angle valve sections only. The fourth spool is for the ripper (9). The
spool is a spring centered, three position type. Incorporated in the valve section is a spring loaded check valve (10)
which assures smooth operation when the spool is moved from hold to an operating position. An anti-cavitation valve
(11) is located in each end of the valve section.
Located in the blade lift rod end and blade tilt rod and head end ports are check orifice (12 or 13) which restrict the flow
of oil. This gives the operator more precise control when lowering the blade and tilting the blade in either direction. As
the oil flows to the cylinder, the orifice button is forced against its seat forcing the oil to flow through the orifice only,
restricting its flow. As oil returns, the orifice button is forced against its "legs" allowing the oil to flow thru the orifice and
around the button sides to allow a greater flow preventing a void from forming.
6. Blade Lift Section
7. Blade Tilt Section
8. Blade Angle Section
9. Ripper Section
10. Load Check Valve
11. Anti-Cav Valve
12. ¼ Orifice Check
13. c Orifice Check
14. Blade Lift Cylinders
15. Blade Tilt Cylinder
HYDRAULICS
16. Blade Angle Cylinders
17. Ripper Cylinders
18. Return Line Filter
19. Vacuum/Relief Valve
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