| 摘要 |
PURPOSE: To finish a gear into a smooth and highly precise involute shape by providing continuous helix cutting edges satisfying the requirement for finishing a cylindrical involute gear. CONSTITUTION: The worm of this finishing hob is a single thread, and the working side of the worm has continuous cylindrical helix cutting edges K. The cutting edges K are formed by the intersection of the rake faces A, i.e., the top surfaces of the worm, and the flanks B, i.e., the working sides of the worm. The normal pitch Pn of the working side of the worm is equal to the normal base pitch of the machined gearπmn .COSαn , where mn is the normal module of the machined gear, andαn is the normal pressure angle at the reference circle of the machined gear. The lead angleλis calculated by the formula Sinλ=(imn COSαn )/2R, where R is the radius of the cylindrical helix cutting edge K, and (i) is a positive integer. The lead P of the helix cutting edge K is P=(iπmn COSαn )/COSλ. The lead P is a straight line inclined at the angleλagainst the working side on the normal cross section of the flank B. |
