Bendix Commercial Vehicle Systems AR-1 ANTILOCK RELAY VALVE 01/11 User Manual

®

Bendix® AR-1™ AntiLock Relay Valve

SD-13-4795

SERVICE PORT

DELIVERY PORTS

™

AR-1

ANTILOCK

RELAY VALVE

SUPPLY PORT

TYPICAL

MOUNTING

BRACKET

SUPPLY PORT

QUICK

EXHAUST

™

AR-1

VALVE

WITH ANTILOCK

CONTROLLER

ANTILOCK

CONTROLLER

QUICK/

EXHAUST DIA.

SERVICE

PORT

RELAY

PISTON

INLET/

EXHAUST

VALVE

DELIVERY

PORT

EXHAUST PORT

DESCRIPTION

The AR-1™ antilock relay valve (Figure 1) is a specialized
service brake relay valve. It is essentially an R-14® relay
valve with a special cover that permits direct attachment
of an antilock controller. When combined with an antilock
controller the resulting assembly is referred to as an
antilock relay controller. For example, when the AR-1
antilock relay valve is combined with the EC-30

™

antilock controller the resulting assembly is referred to as a

™

CR-30
antilock equipped vehicles, the AR-1

antilock relay controller. While intended for use on

™

antilock relay valve
functions solely as a service brake relay and contains no
electronics of its own.

In an air brake system, the AR-1™ valve serves as a
relay station to speed the application and release of
the service brakes. The valve is normally mounted in

™

tractor

EXHAUST PORT

FIGURE 1 - AR-1™ ANTILOCK RELAY VALVE ASSEMBLY

proximity to the service actuators it serves. A mounting
bracket furnished with the valve permits either frame or
cross member mounting. All air connections on the AR-1™
valve are identifi ed with cast, embossed letters for ease of
installation. The letter identifi cation and air line connections
are shown below for reference.

AR-1™ VALVE AIR CONNECTION

EMBOSSED

IDENT.

Supply (to reservoir) SUP
Delivery (to brake actuator) DEL

Service (to brake valve rear service

delivery)

Like the R-14

®

relay valve, the AR-1™ valve incorporates

SER

a quick release valve adjacent to the service port which

1

EC-15™ ANTILOCK

CONTROLLER

TYPICAL

MOUNTING

BRACKET

FIGURE 2 - CR-15™ ANTILOCK RELAY CONTROLLER

™

AR-1

ANTILOCK RELAY

VALVE

provides for rapid exhaust of control air pressure from
above the relay piston. The standard AR-1™ valve is offered
with a 4 psi crack pressure, however, with the addition
of various springs beneath the relay piston, higher crack
pressures are possible.

The AR-1™ valve’s internal components are interchangeable
with the R-12® and R-14® relay valves, therefore, the same
maintenance kit is used to service all three valves.

OPERATION

BRAKE APPLICA TION

Brake application air enters the AR-1
and encounters the exhaust diaphragm which fl exes in
response to the incoming air, sealing the exhaust passage
in the cover. Air fl ows around the exhaust diaphragm and
moves through a passage in the cover to the top of the
relay piston. In response to air pressure, the relay piston

™

valve’s service port

moves into contact with the exhaust portion of the inlet and
exhaust valve. With the exhaust passage sealed, continued
movement of the relay piston unseats the inlet portion of
the inlet and exhaust valve, allowing supply air from the
reservoir to fl ow out the AR-1™ valve’s delivery ports to
the antilock modulators and then to the brake actuators.

(See Figure 3)

HOLDING-BALANCED

The air pressure being delivered to the antilock modulators
and brake actuators is also present beneath the relay
piston. When the air pressure above and below the relay
piston is equal, the piston moves slightly allowing the inlet
valve to return to its seat. The exhaust valve remains
closed. With both the inlet and exhaust valves closed, air
pressure in the antilock modulators and brake actuators
is held stable and neither increases nor decreases. (See

Figure 4)

2

ANTILOCK

CONTROLLER

EXHAUST

QUICK EXHAUST DIA.

SERVICE PORT

RELAY PISTON

SUPPLY PORT

RESERVOIR

FIGURE 3 - AR-1™ VALVE BRAKE APPLICATION

ANTILOCK

CONTROLLER

EXHAUST

EXHAUST

INLET/EXH.

VALVE

ANTILOCK

MODULATOR

BRAKE

ACTUATOR

QUICK EXHAUST DIA.

DELIVERY PORT

SERVICE PORT

SUPPLY PORT

RESERVOIR

FIGURE 4 - AR-1™ VALVE HOLDING - BALANCED

EXHAUST

RELAY PISTON

INLET/EXH. VALVE

DELIVERY PORT

ANTILOCK

MODULATOR

BRAKE

ACTUATOR

3