ARM 2G3724 - Caterpillar

Illustration 1 g06027634
Left Side of Machine
(1) Vibratory motor
(2) Speed sensorThe machine can be equipped with one of two different size vibratory motors. The motor sizes are 21cc and 28cc. The type of vibratory system on the machine dictates the size of motor that is used. The 28cc motor is used on the five-amplitude system. The 21cc motor is used on two-amplitude and Versa Vibe systems.The front and rear vibratory motors are identical. The motors are piston motors with fixed-displacement. Both motors are bent axis. Front vibratory motor (1) is located on front drum on the left side of the machine. The rear vibratory motor is located on the rear drum on the right side of the machine.Rubber isolation mounts dampen the vibration that is transmitted from the drum to the machine when the vibratory system is operating.Speed sensor (2) is located on front vibratory motor (1) and on the rear vibratory motor (not shown). The speed sensors provide input signals to the machine ECM. The ECM uses the input signals from the speed sensors in the vibratory control logic. The sensor input is also used to operate the vibratory tachometer on the operator display.Each vibratory motor contains an integral flushing valve. The flushing spool directs oil from the low-pressure side of the loop into the motor case drain.
Illustration 2 g06027637
Vibratory Motor (cross Section)
(3) Output shaft
(4) Output shaft flange
(5) Piston
(6) Valve plate
(7) Barrel assemblyWhen the vibratory system is operating, supply oil from the vibratory pump enters the motor. Supply oil is directed to the inlet port of valve plate (6). The valve plate directs oil into the piston chamber in barrel assembly (7). Oil pressure forces pistons (5) that are aligned with the inlet port to move out of the barrel assembly.As pistons (5) are forced out of barrel assembly (7), the pistons exert a thrust against output shaft flange (4). In this case, output shaft (3) rotates. The barrel assembly and pistons rotate with the output shaft.As barrel assembly (7) rotates, pistons (5) align with the outlet port in valve plate (6). The rotation of the barrel assembly forces oil out of the piston chambers and into the low-pressure side of the hydrostatic loop. The low-pressure oil acts on the flushing spool (not shown) and then returns to the inlet side of the hydraulic pump.