Takeuchi TB53FR, Руководство по ремонту

Страница: 209 / 447

HYDRAULIC UNITS
TRAVEL MOTOR
IV-99
TB53FR
C4D556
B
When the motor is slowed, the pressure in port P1 and
chamber B rises again and the spool (8) moves to the
left aide, eliminating the back pressure generated at
port M2. In this way, the motor is controlled so that it
rotates at a speed appropriate for the amount of oil
flowing into it.
If the high pressure hydraulic oil introduced into port
P1 is cut off, the pressure at ports P1 and P2 becomes
the same and the spool (8) returns to the neutral
position by spring force. For this reason, the oil in
chamber B is pushed out at port P1. At this time, the
flow of oil is restricted by the orifice (9) as it is
returning to port P1, so the spool (8) returns to the
neutral position slowly. In this way, the motor is
stopped while the shock during stopping is absorbed.
Relief Valve
Operation 1
When the Motor is Started
When the motor is started, since the inertial load is
great, the pressure of the oil required to accelerate it
rises. If this pressure reaches the relief valve set
pressure, the relief valve operates and oil returns to
port M2.
In this way, the motor begins to turn as it relieves the
relief valve, and as the rotational speed increases, the
amount of relief decreases until it stops.
In this way, the shock during starting is absorbed.
When the Motor is Stopped
When the motor is stopped, the return circuit is closed
off.
However, since the motor tends to want to continue
rotating due to inertial energy, the pressure in port M2
rises. When this pressure reaches the relief valve’s set
pressure, the relief valve operates and oil flows to port
M1. In this way, the flow of oil to port M1 prevents
cavitation from occurring as it absorbs the shock
during stopping.
G4D503
P1 P2
M1 M2
G4D504
M2
M1
P1 P2