Kubota WSM B2050 Workshop Manual page 360

B2050, B2350, B2650, B3150, WSM
Roll-back
(1) Boom Control Section
(2) Bucket Control Section
(3) PB Passage 1
(4) Spool
(5) Neutral Passage 2
1. When the hydraulic control lever is set to the "ROLL-BACK" position, the spool (4) of the bucket control section
(2) moves to the left, which forms oil passages between passage 2 (8) and B2 port, and between A2 port and T
port.
2. The pressure-fed oil from the P port flows to the neutral passage 2 (5) through the boom control section (1) and
PB passage 1 (3). As the oil passage from the neutral passage 2 (5) to the PB passage 2 (6) is closed by the
spool (4), this oil opens the load check valve (7), and flows through the notched section of the spool (4) and B2
port to retract the bucket cylinder (9).
3. Return oil from the bucket cylinder (9) flows to the transmission case through the A2 port and T port.
(6) PB Passage 2
(7) Load Check Valve
(8) Passage 2
(9) Bucket Cylinder
P: P Port
T: T Port
PB: PB Port
A2: A2 Port
(From Bucket Cylinder)
8-M17
HYDRAULIC SYSTEM
B2: B2 Port
(To Bucket Cylinder)
a: Low Pressure
b: High Pressure
9Y1210982HYM0020US0
KiSC issued 03, 2014 A