| 摘要 |
PURPOSE:To provide both tooth strength and a practicality by providing specific conditions for a tooth profile of a pair of standard rack defined in either rotational plane or normal plane system. CONSTITUTION:Two standard racks are so constructed that centers of curvature E at the contact points A, B of teeth profiles thereof are held in common on a pitch line l or near it, and a continuously varying curvature is given to at least one tooth profile curve while said curvature comes to a limited value at said contact point A of both said teeth profiles. For example, in cases where the tooth profile of standard racks have a convex circle with a radius r and a concave circle with a radius of curvature r respectively, said standard racks are kept away in a distance of DELTAa from a normal position making secondary contact at contact points A, B at a right angle to said pitch line l. Then, when both teeth surfaces make contact with each other again, said contact points are moved to A', B' but can remain on the circular part. Thus the tolerances of the cutting amount and a center distance of a tooth cutting tool can be taken larger. |
