Types and working principles of gears in automobile transmission


As we all know, the driving of a car is realized by pow […]

As we all know, the driving of a car is realized by power, whether it is a traditional engine or a new energy electric drive, it is nothing more than converting thermal energy or electrical energy into mechanical energy to make the car run. But at this time, the torque from the engine or motor is still relatively small. We need a transmission/reducer to amplify the torque in a certain proportion, reduce the speed and increase the torque, then gear transmission is needed for this realization. In automotive transmission systems, common gear types are as follows:

1. Spur helical gears

Such gears are commonly found in gearboxes of various models, PTUs of SUV models, and EDUs of electric drive three-in-one. The manufacturing process of helical gears is very mature, and these types of gears are used in all walks of life. The precision requirements of the automotive industry are slightly higher, usually ISO 6 and 5.

Because of the helical angle of the spur helical gear, the coincidence degree is higher than that of the general spur gear, because when the gear meshes, it slides along the tooth profile and the tooth direction. The number of gear pairs involved in the LOA meshing line is increased, the transmission is stable, and the transmission error is small. The processing technology is mature, and the automobile industry often uses gear hobbing/shaping for rough machining, followed by grinding or honing. . Depends on product application conditions and requirements. Although this type of gear is relatively common, the competition is becoming more and more fierce now, and the requirements for size and weight, torque capacity, NVH noise requirements, transmission efficiency requirements, etc. are getting higher and higher, so a competitive gear is designed and developed. The product is still very difficult, and often requires a lot of calculation iterations to choose the best balance point.

2. Differential bevel gear

The differential gear, also known as the side gear, is mainly a straight bevel gear, which is installed in the differential casing and plays a differential role. What is differential action? To put it simply, when the car is about to turn, the turning radii corresponding to the wheels on both sides are different. It is conceivable that if the car turns, the distance traveled by the outer wheels must be longer than that of the inner wheels. Differential, the connection between the two wheels is a rigid, the car cannot turn, if you want to turn smoothly, at the same time, the outer wheels need to turn faster to deal with longer distances. So the differential is used to realize the function of differential speed. However, the conventional differential is not differential, which is why some cars, when the left wheel is caught in a relatively slippery snow or ice surface, will cause the wheels to spin quickly but no power output, and the car cannot move forward.

3. Hypoid gear

This type of gear is commonly used in axle products, mostly in rear-wheel-drive passenger cars, SUVs and commercial vehicles. Some electric buses will also be used. The design and processing of this kind of gear are more complicated. At present, it is mainly made by Gleason and Oerlikon. This kind of gear is divided into two types: equal-height teeth and tapered teeth. It has many advantages such as high torque transmission, smooth transmission, and good NVH performance. Because it has the characteristics of offset distance, it can be considered on the ground clearance of the vehicle to improve the passability of the vehicle. There are two common processing types: face milling type face mill and face hobbing type face hob. The face hobbing type is the processing method, which is suitable for the design of equal-height teeth. After this gear is processed, it needs to be paired and ground, marked well, and needs to be assembled one by one. correspond. The face milling type is similar to the forming method, and it is suitable for the reduction teeth. After processing, it can be combined with the grinding process. In theory, there is no need for one-to-one correspondence during assembly.

Although gears have been around for a long time, we can often see them in our lives. But is it really easy to make a gear? It is still not easy. Manufacturing and testing are one aspect. In terms of design, a lot of factors need to be considered comprehensively in order to design gear products with small size, light weight, large load, high efficiency and good NVH performance.Yuhuan FaShiEr gear Co., LTD is Precision Gears Manufacturers
The company is a professional manufacturer of the various precision forging differential gears, with all kinds of mechanical processing equipment, more than one hundred sets, such as 300 T to 1000 T double-tray friction press machine, CNC machine tools, inside and outside round grinder, broaching machine and heating treatment furnace equipment. The company has passed ISO9001:2000 and TS16949:2009 quality management system. The company has strong technical strength, advanced equipment, completed testing method, strict quality management, all kinds of reliable product performance, high quality and reasonable price, long service life and circumspect after-sales service. 

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