according toHard tooth surface gear reducerTooth surface hardness is usually divided into two types of gear transmission, namely hard-tooth surface gear transmission and soft-tooth surface gear transmission.  
    Usually, the tooth surface hardness of a pair of meshing gears is greater than 350HBS, which is called hard surface gear, otherwise it is called soft surface gear.  
    According to the hardness of the tooth surface, people usually divide gear transmission into two types, namely, hard tooth surface gear transmission and soft tooth surface gear transmission.The choice of gear transmission should be based on the design requirements. The two gear transmissions have their own advantages and disadvantages, but they have large hard tooth surface transmission loads, long service life, and wide applications. 

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