How many wheel bearings does a car have？

Bearing is a common part in mechanical equipment, mainly to reduce the friction of rotating mechanical parts in motion. There are many places where bearings are used in cars, such as hub bearings of wheels and bearings of engines, which are very important parts and generally not easy to damage.

Bearings are divided into rolling bearings and sliding bearings。Rolling bearings are divided into axial bearings and radial thrust bearings according to the force direction. According to the rolling body into ball bearings, roller bearings, needle bearings.

First, the engine. Sliding bearings include: crankshaft and cylinder block crankshaft seat, commonly known as big tile, crankshaft and connecting rod, commonly known as small tile, connecting rod and piston pin, camshaft and seat hole, are sliding bearings. Lubricated by oil pump pressure. Crankshaft and cylinder block also useful ball bearings, very few engine accessories such as water pumps are ball bearings.Manual car clutch has a separation bearing, radial thrust ball bearing.

There are two bearings on each shaft in the gearbox. The big car is usually a ball bearing, and the small car is usually a needle roller bearing.

There are four needle bearings for each ten-byte drive shaft. Multi-section drive shafts are supported by ball bearings. Differential is generally ball bearings and tapered roller bearings. Wheel bearings are generally internal and external double tapered roller bearings. Directional machines are usually ball bearings. Radial thrust ball bearings for front steering joints.

The middle balance shaft of rear double-axle truck is tapered roller bearing.

Inside the engine, inside the gearbox,drivetrain, driving system, front and rear wheels. And there's a lot of electrical equipment in the car. CD players, blah, blah,even in the doors of fancy cars.Adjustable seat. It can be said that most of the moving parts of a car have bearings.

Automotive air conditioning compressors generally have only one bearing.Can the bearing of automobile air conditioner compressor be replaced separately if it is broken?  Can't.  Once the bearing of the enclosed compressor is damaged, the whole compressor can only be replaced with a new one.  

Automobile air conditioning compressor is the heart of automobile air conditioning refrigeration system, which plays a role in compressing and transporting refrigerant steam.  Compressors are divided into two kinds of immutable displacement and variable displacement.  According to the different working principles, air conditioning compressors can be divided into fixed displacement compressors and variable displacement compressors.  

According to the different way of working, the compressor can be divided into reciprocating and rotary, common reciprocating compressor crankshaft connecting rod type and axial piston type, common rotary compressor has rotating blade type and scroll type.  

According to the different working principles, air conditioning compressors can be divided into fixed displacement compressors and variable displacement compressors.