3
CF65/75/85 series
Description of components
CLUTCH
3-5
This causes the servo piston (1) to push the air
valve (2) from the valve seat, against the force
of the spring (3).
Air pressure now flows into the cylinder.
The pressure pin (4) is pushed forward by the
air pressure building up on the air piston (5) and
the hydraulic pressure on the fluid piston (6).
The pressure pin (4) pushes against the clutch
lever, which results in declutching.
State of equilibrium
When the hydraulic pressure and pneumatic
support push the pressure pin (4) forwards, a
state of equilibrium is achieved between the air
pressure and hydraulic pressure (status when
the clutch pedal is not depressed any further).
The servo piston (1) again seals off against the
valve seat, closing the air supply and stopping
the build-up of pneumatic pressure.
Clutching
When the clutch pedal is released, there is no
longer any hydraulic pressure and the servo
piston (1) will be pushed back into its original
position by the pressure spring (7) and any
remaining pneumatic support.
As a result, the bleed bore (8) in the servo
piston (1) is no longer closed, and bleeding
takes place via the bleed vent (9).
Vent opening
The function of the vent opening (10) is to
prevent a build-up of pressure between both
piston seals.
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