Item Symbol Formula Example Pinion (1) Gear (2) 1 Center Distance a Set Value 56.4999 2 Center Distance Table 4.4 is the inverse formula of items from 4 to 8 of Table 4.3.Table 4.4 The Calculations for Profile Shifted Spur Gears (2) ( 1 + y – x 1 ) m 4.420 3.700 13 Tooth Depth h m 6.370 14 Tip Diameter d a d + 2h a 44.840 79.400 15 Root Diameter d f d a – 2h 32.100 66.660Ī standard spur gear is, according to Table 4.3, a profile shifted gear with 0 coefficient of shift that is, x 1=x 2=0. Modification Coefficient y z 1 + z 2 / 2 (cos α / cos α w - 1) 0.83329 8 Center Distance a (z 1 + z 2 / 2 + y) m 56.4999 9 Reference Diameter d zm 36.000 72.000 10 Base Diameter d b d cos α 33.8289 67.6579 11 Working Pitch Diameter d w d b / cos α w 37.667 75.333 12 Addendum h a1 Item Symbol Formula Example Pinion (1) Gear (2) 1 Module m Set Value 3 2 Reference Pressure Angle α 20 deg 3 Number of Teeth z 12 24 4 Profile Shift Coefficient X 0.6 0.36 5 Involute α w inv α w 2 tan α (x 1 + x 2 / z 1 + z 2) + inv α 0.034316 6 Working Pressure Angle α w Find from Involute Function Table 26.0886 deg 7 Center Distance This calculation is based on the idea that the amount of the tip and root clearance should be 0.25m.įig.
Table 4.3 presents the calculations where the profile shift coefficient has been set at x 1 and x 2 at the beginning. In the meshing of profile shifted gears, it is the operating pitch circle that is in contact and roll on each other thatportrays gear action.
These values are obtainable from themodified center distance and the following formulas : The key items in profile shifted gears are the operating(working) pitch diameters (d w) and the working (operating) pressure angle (α w). In this case,it will be necessary to resort to profile shifting or to employ helical gears to obtain as near a transmission ratioas possible.įigure 4.2 shows the meshing of a pair of profile shifted gears. Note, that the number of teeth will probably not be integer values when using the formulas in Table 4.2. of Teeth z 1 + z 2 2a / m 36 5 Number of Teeth z z 1 + z 2 / i + 1 i (z 1 + z 2) / i + 1 16 20 Item Symbol Formula Example Pinion (1) Gear (2) 1 Module m Set Value 3 2 Center Distance a 54.000 3 Speed Ratio i 1.25 4 Sum of No. The calculation formulas are in Table 4.1.įig. The meshing of standard spur gears means the reference circlesof two gears contact and roll with each other. The standard spur gear is a non-profile-shifted spur gear.įigure 4.1 shows the meshing of standard spur gears. This section introduces calculation methods of standard spur gears, profileshifted spur gears, and linear racks. The calculations for spur gears are also simple and they are used as the basisfor the calculations for other types of gears. Spur Gears are the simplest type of gear. Tooth dimensionssuch as root diameter or tooth depth are considered when gear cutting. Tip diameter) are necessary for processing the gear blanks. This section introduces the dimension calculations for spur gears, helical gears, gear rack, bevel gears, screw gears, and worm gear pairs.
(if (not (member "geom3d.arx" (arx))) 1).Gear dimensions are determined in accordance with their specifications, such as Module (m), Number of teeth (z), Pressureangle (α), and Profile shift coefficient (x). (setq rads (getdist "\nENTER RADIUS OF WIRE: ")) 3). (setq len (getdist "\nENTER LENGTH OF SPRING: ")) 3 (setq pit (getreal "\nENTER NEW PITCH: ")) 3 (setq rad (getdist "\nENTER NEW RADIUS: ")) 3 (setq seg 36) in one circle become 36 part (defun c:ccs (/ *error* om lay seg ang cnt rad pit len leng x y z point el p1 (setq pb (subst (append '(10) vertex) (assoc 10 pb) pb))Ĭode: ccs is stand for Create Coil Spring (setq vertex (list (+ (car c) (* r (cos Beta))) (defun C:h3(/ c r p n nr ps pb pe Beta dBeta z dz vertex ) To create 3d helical models with non-circular sections, you have to use the Autodesk Mechanical Desktop or some other parametric modeling applications. If you use the created 3dpoliline as an extrusion path, it will rotate the section around the path.
of steps in each revolution to create a 3d helix. It requests you the center, radius, pitche, no. The following autolisp program adds a coomand named "H3" to drawing session.