SDP/SI Introduction - Size Numbers, Ratios & Speed Terms

T-15 Table 1-3C Size Numbers, Ratios & Speed Terms Table 1-4 Equivalence Of American And Japanese Symbols Number of Teeth Equivalent Spur Gear Number of Teeth Number of Threads in Worm Number of Teeth in Pinion Number of Teeth Ratio Speed Ratio Module Radial Module Normal Module Axial Module Contact Ratio Radial Contact Ratio Overlap Contact Ratio Total Contact Ratio Specific Slide Angular Speed Linear or Tangential Speed Revolutions per Minute Coefficient of Profile Shift Coefficient of Center Distance Increase e ea eb eg *s w v n x y Terms Single Pitch Error Pitch Variation Partial Accumulating Error (Over Integral k teeth) Total Accumulated Pitch Error Symbols f_pt *f_u or f_pu F_pk F_p Terms Normal Pitch Error Involute Profile Error Runout Error Lead Error Symbols f_pb f_f F_r F_b z z_v z_w z_l u i m m_t m_n m_x Terms Symbols Terms Symbols backlash, linear measure along pitch circle backlash, linear measure along line-of-action backlash in arc minutes center distance change in center distance operating center distance standard center distance pitch diameter base circle diameter outside diameter root diameter face width factor, general length, general; also lead of worm measurement over-pins number of teeth, usually gear critical number of teeth for no undercutting American Symbol B B_LA _aB C D C C_o C_std D D_b D_o D_R F K L M N N_c Japanese Symbol j j_t j_n a D a a_w d d_b d_a d_f b K L z z_c Nomenclature American Symbol N_v P_d P_dn P_t R R_b R_o R_T T W_b Y Z a b c d d_w e h_k Japanese Symbol z_v p p_n r r_b r_a s i h_a h_f c d d_p h_w virtual number of teeth for helical gear diametral pitch normal diametral pitch horsepower, transmitted pitch radius, gear or general use base circle radius, gear outside radius, gear testing radius tooth thickness, gear beam tooth strength Lewis factor, diametral pitch mesh velocity ratio addendum dedendum clearance pitch diameter, pinion pin diameter, for over-pins measurement eccentricity working depth Nomenclature NOTE: The term "Radial" is used to denote parameters in the plane of rotation perpendicular to the axis. *These terms and symbols are specific to JIS Standards Table 1-3D Accuracy/Error Terms Continued on following page