Bendix Commercial Vehicle Systems TR-3 INVERSION VALVE 8/11 - Manual

1
SD-03-4650
Bendix ® TR-2 ™ & TR-3 ™ Inversion Valves
DESCRIPTION
GENERAL
The Bendix ® TR-2 ™ & TR-3 ™ valves are normally open,
pilot-operated, inverting, on-off, two-way valves. As control
pressure is reduced—to the point that the piston return
spring or springs overcomes the force on the control
piston—the valve will deliver full supply pressure at the
delivery port.
BENDIX ® TR-2 ™ INVERSION VALVE
Referring to Figure 1, the Bendix TR-2 valve was used
primarily in early Bendix
® DD-3 ™ safety actuator control
systems. It applied air pressure to the emergency
diaphragm of the DD-3 actuators from a protected reservoir
as control pressure is released from the lock mechanism.
The TR-2 valve is available in 1-1/4" bulk head-mount only.
BENDIX ® TR-3 ™ INVERSION VALVE
Referring to Figure 2, the Bendix TR-3 valve is similar in
function to the Bendix TR-2 valve, but with a die cast body.
Referring to Figure 3, some TR-3 valves have an internal
passage in the body connecting supply pressure to control.
The external control port is permanently plugged in such
valves.
OPERATION
BENDIX TR-2 & TR-3 INVERSION VALVES
When suffi cient air pressure is present in the control cavity
to overcome the setting of the piston return spring, the
piston is held away from the inlet valve which is, in turn,
held closed by the inlet valve return spring. The delivery
lines are vented to atmosphere through the hollow exhaust
stem of the piston. When air pressure in the control cavity
falls to a predetermined pressure—or is vented from the
control cavity—the piston spring forces the piston against
the inlet valve, closing the exhaust passage in the hollow
piston stem. Further travel of the piston opens the inlet
valve allowing the passage of air past the open inlet valve,
and out the delivery port.
FIGURE 1 - BENDIX ® TR-2 ™ INVERSION VALVE
CONTROL PORT (3)
CAP SCREW
DELIVERY PORT (2)
CAP NUT
SEAL RING
PISTON
MOUNTING NUT
& LOCKWASHER
INLET & EXHAUST
VALVE
PISTON GROMMET
(SMALL)
PISTON GROMMET
(LARGE)
EXHAUST
DIAPHRAGM
COVER PLATE
DIAPHRAGM WASHER
RETAINER RING
PISTON SPRINGS
BODY
INLET & EXHAUST
VALVE SPRING
SUPPLY PORT
EXHAUST