For truck-mounted hydraulic systems, the most common design in use may be the gear pump. This design is usually characterized as having fewer moving parts, being easy to support, more tolerant of contamination than additional designs and relatively inexpensive. Gear pumps are set displacement, also known as positive displacement, pumps. This implies the same level of flow is produced with each rotation of the pump’s shaft. Gear pumps are rated when it comes to the pump’s optimum pressure rating, cubic ” displacement and maximum input speed limitation.
Generally, gear pumps are used in open center hydraulic systems. Gear pumps trap essential oil in the areas between 
your teeth of the pump’s two gears and the body of the pump, transportation it around the circumference of the apparatus cavity and then power it through the store port as the gears mesh. Behind the brass alloy thrust plates, or wear plates, a small amount of pressurized oil pushes the plates tightly against the gear ends to improve pump efficiency.