In the cylinder of a car engine, there are multiple water channels for cooling water circulation. They are connected to a radiator (commonly known as a water tank) placed in the front of the car through water pipes to form a large water circulation system. There is a water pump which is driven by the fan belt to pump out the hot water in the engine block water channel and pump in the cold water. There is also a thermostat next to the water pump. When the car is just started (cold car), it will not open, so that the cooling water does not pass through the water tank, and only circulates in the engine (commonly known as small circulation), until the engine temperature reaches 95 degrees or more When it is turned on, the hot water in the engine is pumped into the water tank, and the cold wind when the car is moving forward blows through the water tank, taking away the heat.
Automobile engines widely use centrifugal water pumps. Its basic structure is composed of water pump casing, connecting disk or pulley, water pump shaft and bearing or shaft-connected bearing, water pump impeller and water seal device, etc. It is the main component of the automobile.
The engine drives the water pump bearing and impeller through the pulley. The coolant in the water pump is driven by the impeller to rotate together, and is thrown to the edge of the pump casing under the action of centrifugal force. At the same time, a certain pressure is generated, and then flows out of the water outlet or water pipe. The pressure at the center of the impeller is reduced because the coolant is thrown out. The coolant in the water tank is sucked into the impeller through the water pipe under the pressure difference between the pump inlet and the center of the impeller, and the coolant is reciprocated.
The bearing that supports the pump shaft is lubricated with grease. Therefore, it is necessary to prevent the leakage of the cooling fluid to the grease to cause emulsification of the grease, and also to prevent the leakage of grease. Water pump seals to prevent leakage are water seals and gaskets. The water seal moving seal ring and the shaft are installed between the impeller and the bearing through an interference fit, and the water seal static seal seat is tightly press-fitted on the casing of the water pump, thereby achieving the purpose of sealing the cooling liquid.
The pump casing is connected to the engine through a gasket and supports moving parts such as bearings. The pump casing also has a drain hole, located between the water seal and the bearing. Once a coolant leaks through the water seal, it can be drained from the drain hole to prevent the coolant from entering the bearing cavity, which can damage bearing lubrication and cause component corrosion. If the coolant still leaks after the engine is stopped, the water seal is damaged.
The crankshaft of the engine is driven by a V-belt. The transmission belt is surrounded between the crankshaft pulley and the water pump pulley. As soon as the crankshaft rotates, the water pump shaft also runs, and the water pump shaft drives the impeller to rotate, thereby achieving the conversion of mechanical energy into hydraulic energy.
The impeller is the core of the pump. The movement of the impeller itself is very simple, it just rotates with the shaft. However, due to the action of the blades, the movement of the liquid in the impeller is very complicated; on the one hand, the impulse movement is caused by the rotation of the impeller; Therefore, the outer diameter of the impeller, the height and angle of the impeller blades, and the clearance with the pump casing directly affect the performance of the pump.