Sakai SV414, Руководство по ремонту

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HYDRAULIC SYSTEMS
2-3. Description and Operation of Propulsion System
Description
Made up of propulsion pump (3), propulsion motor (R) (6), rear axle ASSY (7), propulsion motor (F) (17), drum
(15), speed change solenoid valve (F) (8) and parking brake solenoid valve (9).
Rear axle ASSY (7) includes differential (j), final drives (k), tires (m) and brake (n).
Basic function of propulsion pump and motor
Propulsion pump:
A piston pump is used. By varying swashplate angle which varies the piston stroke, forward travel, bringing to
neutral and backing are achieved.
Propulsion motor:
Piston motors are used. The motor is a variable displacement type which controls the piston stroke by varying
the swashplate angle.
Operation (It is assumed that the machine travels forward.)
The parking brake is supposed to have been released.
Assemblies such as pump ASSY and motor ASSY are indicated by numbers such as “1” and “2”, while
component parts of assemblies are shown by small letters such as “a” and “b”.
Operation of the F-R lever forward puts pump control valve (a) into function. Servo piston (c) tilts the pump
swashplate in the forward travel direction.
Propulsion pump (3) discharges oil from its port B1. Then the oil flow branches into two lines; one line
connecting to forward travel port (A) of propulsion motor (R) (6) and the other line to forward travel port (B) of
propulsion motor (F) (17).
The oil fed into the forward travel ports of the motors drives the motors, flowing out from the opposite side ports
(port A in propulsion moto (F) and port B in propulsion motor (R)) and joins again to flow into suction port (A1) in
propulsion pump (3). At the same time, part of oil is drained to the tank via flushing valve (g), low pressure relief
valve (h), and the motor casing
(NOTE)
Because the propulsion circuit is a closed circuit, the relationship between the suction port and
discharge port is reversed when the travel direction is reversed.
The power from propulsion motor (R) (6) is delivered to tires (m) through reduction mechanism in differential (j)
and final drives (k).
The drive from propulsion motor (F) (17) is conveyed to drum (15) via reduction gear (16).
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