Forming hobbing of arc gears for timing instruments (for reference)

The relevant instructions for forming and hobbing of arc gears for timing instruments are as follows for reference.

The most commonly used cutting method of circular arc gears for timing instruments is the hobbing method.Due to the limitation of tooth profile parameters, not all tooth profile parameters can meet the hobbing conditions required by the hobbing method.So there is a partgearIt cannot be processed by the rolling method.

The forming hobbing law is extremely widely used and is not limited by the hobbing conditions, and can hobbing and cutting arc gears for timing instruments of any parameter.

Forming hobs can be divided into assembly type, welding type, and integral type according to the structure; according to the number of screw heads of the tool, it can be divided into single-head and multi-head forming hobs.

The forming hob processed by the circular arc gear of the timing instrument uses a single-head solid carbide tool, which has 10 teeth, and the teeth are distributed on the same spiral line.The arrangement of the cutter teeth is shown in the figure below.Among them, No. 1 tooth is a fine cutting tooth, and the remaining teeth are rough cutting teeth.

The tooth shape of the forming hob changes according to its position in the cutting process.

Form hobbing is also applicableInvolute gearAnd non-involute tooth profile processing.