Sakai SV414, Shop Manual

Page: 79 / 294

4-024
HYDRAULIC SYSTEMS
3-3. Description and Operation of Vibrator System
Description
Made up of vibrator pump (4), vibrator motor (6) and vibrator (7).
Basic function of vibrator pump and motor
Vibrator pump:
A piston pump is in use. Varying the pump swashplate angle varies the piston stroke to select low amplitude,
neutral and high amplitude.
Vibrator motor:
A fixed displacement piston motor is used.The displacement per rotation of the motor shaft is not variable.
Operation (It is assumed that HIGH amplitude is selected.)
The operation of the vibration select switch actuates amplitude select valve (a) built in vibrator pump (4) to
discharge oil from the high amplitude port (port A).
Oil fed into the high amplitude port (port B) of the motor powers the motor and displaced from the opposite side
port (port A), getting back to the pump suction port (port B).
(NOTE)
Because the vibrator system also uses a closed circuit (HST) like the propulsion circuit, every time the
amplitude election is changed from low amplitude to high or vice versa, the function of the pump inlet
and outlet is reversed with each other.
Circuit protection against high pressure
High pressure relief valves (c) built in the vibrator pump (4) relieve pressure to protect the circuit when the
pressure exceeds the setting of the valves.
Charge circuit
The vibrator circuit is also of a closed circuit, which needs feeding of oil into it for making up for deficiency and
for other purposes.
In the charge circuit, oil from steering • charge pump (5) flows into Orbitrol (8), then the whole amount of oil
goes to propulsion pump (3) via hydraulic oil filter 1 (9) irrespective of the steering wheel operation.
Charge relief valve (b) maintains the charge pressure when the machine is not in motion. When travelling, the
charge pressure is kept by the low pressure relief valve (h).
For the “2-3. Description and Operation of Propulsion System”, refer to page 4-018.
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