Practice of machining large gear combs

Writer： admin Time：2024-02-27 14:07:43 Browse：72℃

      The comb method of using rack and pinion cutters to machine cylindrical gears based on the principle of generation has been around for more than 100 years and has been widely applied since the 1980s. In many cases, the efficiency of comb teeth is not inferior to that of gear hobbing, and their processing quality and economy are superior. Some research results and production practices have shown that when the gear modulus is large (about mn>10-12mm), the efficiency of the comb teeth is higher than that of the hobbing teeth, as the hardness of the gear material increases. The advantages of comb teeth in production efficiency are more significant. There is no principle error in comb tooth machining (both axial and normal sections with straight tooth profiles have principle errors in hob hobbing, which increase with increasing modulus)

     The circumferential amount (number of enveloping times) can be manually selected, and its generating motion is not affected by cutting force (stopping generating during the cutting stroke). The simple structure of comb cutting tools can achieve high manufacturing accuracy and grinding quality, so the machining quality of comb teeth has better guarantee conditions, especially in terms of smoothness, contact accuracy, and tooth surface roughness, which are generally better than hobbing. It is relatively easy to obtain gears with 6-7 levels of precision (din) through comb tooth machining. The cost proportion of the comb cutter in the gear cutting process is relatively low (manufacturing and grinding costs are low, and it can be reused more than 50 times). The process economy is excellent, and it has more advantages when processing single large module gears.