293
294
295
WORMGEARING
297
Spreadsheet solution to Problem 10-18. Small differences from the solution on the preceding
page are due to rounding differences and reading of data from graphs, rather than calculations.
298
Comments on the following Problems 19 and 20:
Wormgearing
oDW
Problems 10-19 and 10-20 COMPARISON OF THREE PROPOSED DESIGNS
Summary See details on the preceding three spreadsheets
Given data:
Diametral pitch, Pd = 12
Assumed gear is made from chilled cast phosphor bronze
Allowable bending stress = 24,000 psi
Results: DESIGN
A B C
Number of threads in worm: 1 2 4
Output torque (lb-in), To = 202 484 878
Comments on results:
The given face width is small. Could use F > 0.601 in to maximize effective face width.
Worm diameter is too large for Design A. See Equations 10-52 and 10-53
Worm diameter is too small for Design C. See Equations 10-52 and 10-53
Design A is limited by surface durability
Designs B and C are limited by bending stress in gear teeth.
As number of threads in worm increases:
Lead angle increases
DW
304
Spreadsheet solution to Problem 10-21.
305
Spreadsheet solution to Problem 10-22.
306
307
Spreadsheet solution to Problem 10-24A.
DW
DW
308
Spreadsheet solution to Problem 10-24A – Modified: DW
309
Spreadsheet solution to Problem 10-24B.
310
COMPARISON OF THE RESULTS FOR PROBLEMS 10 24A, 10 24A (REV.), AND 10 24B
Wormgearing
Problems
Comparisons for: 10 24A 10 24A (Rev) 10 24B
Common data:
Variable data:
Diametral pitch, Pd6 6 10
Computed results:
Forces (on gear):
Observations:
Bending stress for Design 24B are much higher