Ancient gears were formed by hand repair. In 1540, Italy's Toriano made a cutting device using a rotary boring tool when making watches; in 1783, France's Rene made a gear processing machine using a milling cutter, with a cutting rack and inner Accessories for gears; around 1820, White in the UK produced the first machine that could process both cylindrical gears and bevel gears. Machine tools with this performance have developed in the second half of the 19th century.

       In 1835, Whitworth in the United Kingdom obtained the patent for the worm gear hobbing machine; in 1858, Schiller obtained the patent for the spur gear hobbing machine; after several improvements, it was only in 1897 that the German puffer made the hobbing machine with the differential mechanism. Successfully solved the problem of machining helical gears. After making gear-shaped pinion cutters, Felos of the United States made a gear shaping machine in 1897. At the beginning of the 20th century, due to the needs of the automotive industry, various gear grinding machines were introduced. A shaving machine was made in the United States around 1930; a caries machine was made in 1956. After the 1960s, modern technology was applied to some advanced cylindrical gear processing machines, such as digital display indicating the amount of movement and cutting depth on large machine tools; electronic servo system and numerical control system on gear hobbing machine, gear shaping machine and gear grinding machine. Replace mechanical transmission chain and exchange gear; use programmable controller with fault diagnosis function to control working cycle and change cutting parameters; develop digital control non-circular gear shaping gear and adaptive control gear hobbing machine; use electronic sensor on gear hobbing machine Detect the motion error of the drive chain and automatically feedback the compensation error.

       In 1884, Bill Gram of the United States invented a straight bevel gear planer that was machined by a single planer. In 1900, Bill of the United States designed a double-cutter-milled straight bevel gear.

      Due to the needs of the automotive industry, a straight bevel gear planer with two planing knives was made in the United States in 1905, and a spiral bevel gear milling machine was made in 1913; in 1923, a quasi-involute toothed tooth appeared. Bevel gear milling machine; developed in the 1930s as a gear broaching machine capable of broaching straight spur gears, mainly used in the manufacture of automotive differential gears.

      In the 1940s, in order to meet the needs of the aviation industry, a spiral bevel gear grinding machine was developed. In 1944, the Swiss company Oerlikon made the extended outer cycloidal bevel gear milling machine; since the 1950s, it has developed a double-knife combined end mill cutter to machine the extended outer cycloidal bevel gear. machine.

       Gear processing machines are mainly divided into two categories: cylindrical gear processing machines and bevel gear processing machines. Cylindrical gear processing machines are mainly used to process various cylindrical gears, racks and worm gears. Commonly used are gear hobbing machine, gear shaping machine, gear milling machine, shaving machine and so on.

      Gear processing

      Fan Chengfa: Using the principle of gear meshing

       One of the gear meshing pairs (rack-gear, gear-gear) is converted into a tool; the other is converted into a workpiece, and the tool and the workpiece are forced to perform a strict meshing motion to cut the tooth profile.

      The shape of the cutting edge of the tool used by Fan Chengfa is equivalent to the tooth profile of the rack or gear, which is independent of the number of teeth of the gear being cut.

      For each type of modulus, only a single tool can be used to machine gears with different numbers of teeth; continuous indexing during machining, high processing accuracy and productivity, and wide application.

      This method must be machined on a special gear machine, and the adjustment of the machine tool, the manufacture of the tool and the sharpening of the tool are complicated, and are generally used for mass production in batches.