Special terms for gears

1. Tip relief of gear

(1) Crown part trimming (general): It is to cut the crown part into a slightly convex shape than the correct involute by a special processing method. Therefore, when the tooth surface is deformed by the transmission force, it will ease the occlusion of each other. The interference caused by gears can reduce the noise during biting and increase the life span, and the effect is remarkable. However, if the trimming is excessive, it will have an adverse effect on gear meshing just like a gear with increased tooth profile error.

(2) Partial dressing of tooth root 2. Cutting drum-shaped tooth tendons and cutting end tooth tendons (Cowning, Relieving) Drum-cutting processing and cutting end processing are both trimming methods in the direction of tooth tendons. In particular, the drum cutting process is to concentrate the contact of the tooth surface on the central part of the tooth width, so that the tooth ribs are trimmed into a slightly drum shape. If the drum shape is too large, it is equivalent to reducing the contact area of ​​the tooth shape and the strength of the tooth shape Have adverse effects. As for the cutting end processing, the two ends of the tooth tendons are slightly chamfered, so that the effect of the tooth tendons is similar to that of a drum.

(3) Outer diameter hobbing and outer end chamfering (Topping and Semitopping) While the gear hob is used to create and process the tooth profile, by the way, the outer diameter of the gear is hobbed or the top of the tooth is chamfered. Back form cutter (Back form cutter) creates the tooth profile while cutting the outer diameter of the gear. Because the outer diameter of this gear is cut synchronously with the tooth profile, the deviation of the outer diameter is the lowest and the burrs generated by the tooth profile can be removed. The shape of the tool used for chamfering the outer end and the tooth shape that is cut by creation. This tooth shape can prevent frequent marks and burrs from the tooth tip. If the outer chamfer amount is too large, the effective crown height of the tooth profile will be significantly reduced, and the occlusal rate will also decrease, so it is generally not desirable to excessive outer chamfer.