Takeuchi TB53FR, Руководство по ремонту

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HYDRAULIC UNITS
SLEW MOTOR
IV-123
TB53FR
Operation 2
Since this relief valve has a shockless mechanism, it
operates in 2 steps.
1st Step
When relief valve operation starts, the pressure in
chamber B (P1) is kept at a pressure which is lower
than that in chamber C while the pressure in chamber
A (P) becomes higher than the pressure of the oil
flowing in.
At this time, there are two forces acting on the poppet
(10), force (F), which attempts to move the poppet
(10) to the left and force (F1) which pushes against the
seat on the right side. Since F = P
×
A, F1 = P1
×
A1,
P > P1 and A > A1, the poppet (10) is moved to the left
by this force “F-F1”.
This opens a supply side circuit from chamber A and
lets the pressure escape. That is, during the time piston
(11) is moving to its stroke end, the relief valve
operates at low pressure (about 1/3 the set pressure).
2nd Step
When the piston (11) reaches the stroke end, the
pressure in chamber B rises and the pressures in
chamber A and chamber B equalize. At this time, the
force moving the poppet (10) to the left side becomes
“P = P1”, so this becomes “A-A1” and the relief valve
operates at the specified set pressure.
Anti-rebound Valve
When the motor stops, this valve will connect the
motor main circuit to the makeup circuit for a pre-
scribed time to prevent motor rebound due to the
pressure in the main circuit.
When the Brake is Actuated
The braking pressure generated at the port Pv1 will
move the check valve (2) to the right until it is seated
at section B.
When the Motor Rebounds
When the motor is stopped by braking operation of the
brake valve, it starts to rebound due to the pressure in
the main circuit. This rebound pressure generated at
the port Pv2 will move the sleeve (3) to the left to open
the passage. This then releases the rebound pressure
to the port Cv.
A 10
B
P P1
11
E5D636
G4D604
2 B
Pv1 Cv Pv2
G4D605
Pv1
Cv
Pv2
B 3