Caterpillar oil pumps
The Caterpillar oil pump is designed to create pressure in the lubrication system, and thus lubricate the moving parts of the internal combustion engine.
By the nature of the control oil pumps are divided into uncontrolled and adjustable. Unregulated pumps maintain a constant pressure in the lubrication system by means of a pressure reducing valve. In controlled pumps, the constant pressure is maintained by changing the pump capacity. Depending on the design, oil pumps are distinguished for gear and rotary pumps.
Caterpillar gear oil pump is a two-pinion gear - the driving and slave, housed in the body. Oil enters the pump through the suction channel, is captured by gears and injected into the system through the discharge channel. The output of the gear pump is proportional to the speed of the crankshaft. When the discharge oil pressure exceeds a certain value, the pressure relief valve operates and passes a part of the oil into the suction cavity or directly into the crankcase of the engine.
The rotary oil pump combines two rotors - the internal (master) and external (slave), which are placed in the housing. The oil is sucked into the pump, captured by rotor blades and injected into the system. Just like in the gear pump, if necessary, the pressure relief valve works. The design has an uncontrolled rotary pump.
A more refined design is the Caterpillar adjustable rotary oil pump, which provides constant pressure over the entire speed range of the crankshaft.
Principle of operation of an adjustable rotary pump
When the engine speed of the Caterpillar engine is increased, the need for oil increases and, accordingly, the pressure drops in the system. With the pressure drop, the adjusting spring moves the stator, which in turn changes the position of the driven rotor. Accordingly, the volume of the suction cavity is increased and the productivity of the pump is increased.
When the engine speed is reduced, the oil consumption decreases and the system pressure is increased. By increasing the pressure, the adjusting spring is compressed, which moves the Caterpillar stator and changes the position of the driven rotor. This leads to a reduction in the volume of the suction cavity and a decrease in the productivity of the Caterpillar pump.
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