Gear non-standard fine hob

The current trend is that a large number of factories order and use non-standard hobs. Gear hob design engineers can design and manufacture special gear hobs according to the actual requirements of customers. All specially designed precision hobs are based on standard gear hobs. Non standard hobs will not be classified by hob accuracy grade, which mainly depends on the required gear accuracy.

The purpose of adopting taper hole for gear hob is to minimize the installation runout and reduce the time of installation on the cutter bar. There must be strict tolerance requirements between gear hob and spindle to ensure the accuracy of cutting. Because the tapered hole usually requires a gear hob with a larger diameter than the corresponding standard gear hob, the cost is relatively high.

For Gear Hobbing with higher precision requirements, AA grade ultra precision gear hob is usually used. This kind of gear hob has higher accuracy grade than ordinary gear hob, and can provide customers with the best high-precision gear. Generally, it is recommended to use tapered holes to further control the accuracy of gears.

The gear hob with chamfering at the tooth top is another non-standard hob. The main purpose of this gear hob is to deal with the involute profile of the gear, so as to avoid stress concentration and cracks in the meshing process. In addition, it can also be used to eliminate or reduce burrs caused by machining involute tooth profile.

Cutting chamfer on gear hob is called root trimming, and it must be designed according to the requirements of parts. Therefore, the gear hob design engineer must know the number of teeth, helix angle (and direction), chamfer size and angle. If the tooth top of the part is also required to be finished by the hob during gear hobbing, this gear hob can ensure the concentricity of the tooth top of the part with the indexing circle.

Therefore, the tooth thickness of gear hob must maintain a certain corresponding relationship with the root circle diameter of hob, and the tooth thickness can be determined by measuring the outer diameter of gear. However, when the gear hob is changed, the first part must measure the span distance to determine the tooth thickness of the part.

Although standard gear hobs can also achieve good accuracy, some projects requiring precision machining and production do not need to use these gear hobs. In this case, gear hobs with larger diameter (with more heads) should be recommended to balance accuracy and efficiency.

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