GEAR-SUN 3277185 - Caterpillar

Illustration 1 g00975589
The metering pump is made up of the following two sections:
Control section (1)
Metering section (2) The two sections are connected by hydraulics and by mechanics. The two sections work together in order to send oil to the steering cylinders.Pump oil goes through the inlet port into control section (1). When the steering wheel is turned, control section (1) sends oil to metering section (2). Metering section (2) produces a specific amount of oil flow. Metered oil from metering section (2) is then directed by control section (1) to either the left turn port or the right turn port.Metering section (2) is a small hydraulic pump. The hydraulic pump produces a metered amount of oil flow. Then, the metered oil is directed by the control section (1) to the steering cylinders.The direction and the speed are controlled by the metering pump. As the steering wheel is turned faster, there is an increase in the flow of oil from the metering pump to the cylinders. The increased flow causes the cylinders to move faster. The result is faster movement of the machine.The front end of the machine stays in the turned position when the steering stops. The steering wheel must be turned in the opposite direction in order to straighten the machine.When the machine is off, the metering pump can be manually operated. The metering section operates as a pump. The suction of the metering section opens the internal check valve (11). When the internal check valve opens, return oil flows from the steering cylinder to the inlet side of the metering section. During power operation, supply pressure keeps the check valve closed. The internal check valve (11) converts the metering pump into a hand operated pump for limited manual steering.