Multi head gear hob is not a new concept. In the actual production, the experience of using this type of cutter is summarized and improved to increase the application range of multi head gear hob. We will discuss the application of multi head gear hob in this section.
Like other gear hobs, multi head gear hobs also adopt two types: straight hole and tapered hole. Other parameters can refer to the tool standard. Compared with the same gear hob, the more the number of heads, the lower the tool accuracy. Therefore, this type of gear hob is mainly used in the semi finishing process. Of course, they are sometimes used to directly process the finished gear. The accuracy and requirements of parts are the decisive factors in the design and application of multi head gear hobs. The design of multi head gear hob has also been introduced in the previous chapter. For those parts that do not require high precision but have certain requirements for production efficiency, multi head gear hobs can greatly improve the output, prolong the tool life and reduce the number of tool reserves.
In addition, attention should be paid to some problems in the use of multi head gear hobs. When the equipment conditions are better, compared with the single head gear hob, the metal cutting rate of this gear hob is larger than that of multi head gear hob, and higher efficiency can be obtained. Most tool manufacturers can inspect multi head gear hobs. In addition, since the runout accuracy of multi head gear hobs is worse than that of single head hobs, tapered holes should be used as much as possible to ensure the clamping accuracy of gear hobs. Therefore, the adjustment of multi head gear hob is more difficult and more suitable for the production of large quantities of parts.
Class B and class C gear hobs are generally used in the manufacturing of automobile and truck gearbox gears. These gear hobs have been repeatedly tested and used in mass production. The cost has been reduced to very low, and the processing efficiency is also very high. However, it is worth noting that the number of heads of gear hobs cannot be divided by the number of teeth of the part. At present, the processing efficiency of gear hobbing in most factories (such as 22 tooth gear parts) is 85% higher than that 20 years ago. The tooth direction can also be guaranteed to be within 0.013mm, which makes the quality and efficiency of shaving process higher. Such an increase has greatly reduced the average cost of the whole gear parts.