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What Is a Pump Pulley?

Jean Marie Asta
Jean Marie Asta

A pump pulley is any kind of pulley that uses a fluid, like water, to pump and transmit power via a pulley. These types of pulleys are often found in automobile parts and industrial machinery for heavy workloads. Over decades, the pump pulley in automobiles has been made more compact, lightweight, efficient and economical. Compact and lightweight pulleys mean better efficiency and better long term economic quality. It is especially important for these pumps to have these qualities because automobiles have a number of pump pulleys that serve different purposes.

Automobile water pumps are housed in a shell of resin and have an outer protective covering. Cool water is circulated by a rotary shaft, which is the pump, at one end. It is then driven by the engine’s crankshaft, which is the rotating driver pulley. The driver pulley uses centrifugal force to spin the water continuously away from the center of the pump, eventually leading into the engine block and cylinder heads to cool them. The pump pulley system is just one part of the engine cooling process in a car.

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Woman holding a book

The pump pulley is used in power steering systems as well. Under pressure, the hydraulic fluid flow rate is slowed while there is an increase in engine speed above idling speed. The rates of these preceding factors vary depending on the make of the vehicle, type of engine, and type of power steering system. A valve to control flow that is positioned parallel to the pump mechanism’s axis has a changeable area orifice to adjust the fluid flow rate. The orifice has a flange with a groove cut into a divided wall, and the valve is arranged to freely detach from the vehicle’s pump mechanism and be connected to the orifice to change the rate of fluid flow as needed.

Power takeoffs, or take-offs, which are usually found on tractors and semi-trucks, use a pump pulley and a hydraulic system to provide power to attachments and separate machines. These devices are splined drive shafts that draw power from the engine of a truck or tractor to use elsewhere. The power takeoff consists of a hydraulic system pump that is connected to a pivot arm in a bracket attached to the engine. A pump pulley is positioned and aligned above the engine’s drive shaft pulley, transmitting or opposing power to a secondary entity. These drive shafts that utilize pump pulleys can also be found on industrial machines and marine engines.

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