3 - 5
Automatic 2-Speed Switching
Speed range changing is achieved by altering the angle of
the traction motor swash plate. A solenoid operated valve
routes pilot oil to the swash plate adjusting mechanism, as
appropriate, in response to range selection commands.
Low speed Operation
When ‘low speed’ is selected, pilot pressure than 10kgf/cm
2
is supplied from port A.The valve
163
is pushed to the left
side by spring
166
. In this state the pressurised oil in port B
is blocked and the oil in chamber C is released into the
motor case through the valve.
The swash plate
103
pivots on fulcrum
F
to the maximum
angle (O1). In this swash plate position the piston stroke
volume is maximised to produce low speed revolution.
High Speed Operation
When ‘high speed’ is selected, pilot pressure greater than
19.6 bar (284 lbf/in
2
, 20 kgf/cm
2
) is applied to port
A
where it
overcomes the force of spring
166
and pushes the valve
163
to the right. The pressurised oil in port
B
flows to chamber
C
to valve
163
. The piston
161
pushes the swash plate
103
upwards until it touches the b surface of the spindle.
The swash plate
103
pivots about its fulcrum
F
and is set to
the minimum angle (O2) position, the piston stroke volume is
minimised to produce high speed revolution.
Section F
Transmission
9803/6020
Section F
3 - 5
Issue 1
Operation
291180
291190
F
F
Summary of Contents for JS70
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