The Fan Pump is the power source of the hydraulic cooling circuit of large excavators,also known as the cooling fan pump.Most of them are variable displacement piston pumps,and some models are gear pumps.The output pressure oil drives the Fan Motor to rotate,driving the cooling fan to operate and heat the water tank and hydraulic oil radiator.Different from Belt driven fans,hydraulic fans can achieve stepless speed regulation based on engine water temperature and hydraulic oil temperature.Some models support fan reverse blowing to clean the radiator,and are mostly used for medium and large excavators.

　　Fan pumps are generally driven by the engine gearbox or transfer case,and the assembly includes the pump body,plunger distribution plate,variable mechanism,and proportional solenoid valve.The whole machine controller collects water temperature and hydraulic oil temperature signals,adjusts the current of the proportional solenoid valve on the fan pump,changes the output displacement of the pump,and thus changes the fan speed.When the temperature is low,reduce the flow rate and slow down the fan to reduce power loss;The temperature rises,the displacement increases,and the fan runs at high speed to enhance heat dissipation.

　　The complete cooling oil circuit process:fan pump output pressure oil→fan motor rotation→return oil returns to the hydraulic oil tank through the cooling return Oil filter element.The internal plunger and distribution plate of the pump rely on hydraulic oil lubrication,and metal impurities in the oil can easily strain the friction pair.Under heavy load conditions in mines,the fan pump has a long-term high displacement output,resulting in significant pressure shock and faster wear and tear;The medium load condition of earthwork is relatively stable.

　　Fan pump failure does not trigger a separate alarm.Common phenomena include high water temperature and hydraulic oil temperature,inability to increase fan speed,or continuous high-speed rotation of the fan,resulting in loud noise,high power consumption,and stalling of the speed.Many repairs only check the fan motor,ignoring the upstream fan pump,and repeatedly repairing the motor still causes problems.Fan pumps are high-value hydraulic components.Once they experience internal wear and insufficient output flow and pressure,it can directly cause high temperatures in the entire machine,leading to seal aging and accelerated damage to components.

　　Familiar with the working logic of fan pumps and paying attention to the maintenance of hydraulic oil and return oil filter elements can reduce early damage to fan pumps,avoid high-temperature shutdown of the entire machine,and ensure continuous equipment construction.