Tham khảo tài liệu 'gear geometry and applied theory episode 2 part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Pointing of Face-Gear Teeth Generated by Involute Shaper 523 Figure Cross section profiles of face-gear and shaper in plane n2- n2 is designated by A Fig. . Point A has to be located on the addendum line of the face-gear and therefore its location with respect to axis ya is determined by rps 1 Pd Fig. . The goal is determination of magnitude L2 defined by distance Al between planes n1 and n2 Fig. . Figures and illustrate the procedure of derivation of magnitude Al and L2. The computation of L2 is based on the following procedure Step 1 Determination of pressure angle a of pointed teeth Fig. . We use vector equation Fig. O N NM MA O A. See the location of point O in Fig. . Here _ . 1 O A rps p P d Ns 2 2 Pd where Pd is the diametral pitch point M is the point of tangency of profiles of the shaper and the face-gear in plane n2 Fig. MA Ks NM rbs0s. Vector equation yields two scalar equations in two unknowns a and Ks rbs cos a Ss sin a Ks cos a Ns 2 2 Pd rbs sin a Ss cos a Ks sin a 0. Here rbs Ns 2 Pd cos a0 9s a Ớ0s Ớ0s n 2 Ns inv a0. Eliminating Ks we obtain the following equation for determination of a Ns 2 n a sin a ------- ------inv a0. Ns cos a0 2 Ns 0 The sought-for angle a is obtained by solving the nonlinear equation . 524 Face-Gear Drives Step 2 Determination of magnitude L2 Fig. . Figure yields rbs Ns cos a 0 Oa1 . cos a 2 Pd cos a Then we obtain Fig. Oa I Ns cos a0 tan Ys 2 Pd cos a tan Ys Knowing the magnitudes of L1 and L2 Fig. it becomes possible to design a face-gear of the gear drive that is free of undercutting and pointing. FILLET SURFACE Two types of fillet surfaces might be provided i those generated by the generatrix G of the addendum cylinder Fig. a and ii those generated by the rounded top of the shaper Fig. . Case 1 Generation of the fillet by edge G Fig. a
