Calculation of Contact Ratios for Plastic/Plastic or Plastic/Steel Spur Gear Pairs

Abstract

An analytical method is presented for calculating real contact ratios for plastic/plastic or plastic/steel spur gear pairs. A comparison is made with published experimental data and the method is used to explain the importance of load sharing in thermoplastic gearing.

Tooth stress calculation of metal spur and helical gears

“…In ISO standard 6336 [1,2] as well as in other works [14][15][16][17], only a simplified model of the tooth is considered for the calculation of the deflection of the tooth profile. This simplified model represents a trapezoidal rack tooth with the same standard basic rack tooth profile as the gear.…”

Stress calculation for plastic helical gears under a real transverse contact ratio

“…Several approximations of tooth profile can be found in the literature [12][13][14]. Many of those approximations specify that the deflection of the tooth is the sum of the deflections due to bending x b , axial compression x c , and shear x s .…”

“…Also, some studies have focused on studying the load and stress distribution on gear teeth [8][9][10] without taking into account the effect of premature meshing of gear teeth during engagement. A study of this kind has been conducted by Yelle and Burns [12,13] for the case of spur gears made of plastic materials.…”

Static and Dynamic Transmissin Error in Spur Gears

“…(1a) to find the influence of load distribution between teeth on effective gear errors. Following Yelle and Burns [9] and Remmers [10] the tooth profile is represented as a slide (Fig. 1a) and the teeth as springs with rollers.…”