Kubota BX1870 Workshop Manual

HYDRAULIC SYSTEM
BX1870,BX2370,BX2670,LA203A,LA243A,RCK48(P),RCK54(P),RCK60B,RCK60D,RCK54D, WSM
5-M7
5. RELIEF VALVE
The implement control system circuit has a relief valve to restrict the maximum pressure in the circuit. The relief
valve is located in the hydraulic control valve assembly.
The relief valve is a guide piston type with damping effect.
Among direct acting relief vales, this type is suited to higher pressure and has large capacity. Furthermore, this
type is free from unstable operation, such as chattering, which occurs often in direct acting relief valves.
As shown in the figure, the guide is attached to the poppet (7) and a valve chamber D.C. (called the damping
chamber) is formed at the top of the guide piston. The inlet of the valve leads to the chamber via a clearance between
the sliding portion of the guide and the seat (6), minimizing valve vibration with the damping effect of the chamber.
9Y1210855HYM0008US0
(1) Hydraulic Pump Gear
(2) Hydraulic Pump Case
(3) Plug
(4) Flow Priority Valve
(5) Relief Valve
(6) Seat
(7) Poppet
EF: EF Port (To 3 Point Hitch
Control Circuit)
PF: PF Port
(To Power Steering, PTO
Clutch and HST Circuit)
D.C.: Damping Chamber
P: Pump Port (Suction)
T: Tank Ports
KiSC issued 02, 2017 A

Kubota BX1870 Specifications

General

Engine Type	Diesel
Engine Power	18 hp
Transmission	Hydrostatic
Fuel Capacity	6.6 gallons
Wheelbase	55.1 inches
Type	Sub-Compact Utility Tractor
Engine	Kubota D722
PTO Power	13.5 hp
Number of Cylinders	3
Cooling	Liquid
Drive	4WD
Drive Type	4WD
Width	44.5 inches
Hydraulic System Type	Open center
PTO Speed	540 RPM
Displacement	0.719 L
Fuel Tank Capacity	6.6 gallons
Gears	Infinite (2-range) forward and reverse
Front Tire Size	18x8.5-10
Rear Tire Size	26x12-12