Identifier: wormgearing00thom (find matches)
Title: Worm gearing
Year: 1916 (1910s)
Authors: Thomas, Hugh Kerr
Subjects: Gearing, Worm
Publisher: New York : McGraw-Hill Book Co.
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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rium 0.07 0.06- g0.05o m0.04 6 0.03 0.02 0.01 i\t;, ar w — \\V ^V = 19.34 i.p .s. w c ^ \ Y ^=28.3 J / V / e \ !^ to.85^ x^/ \\\ f^ y y -^ y - \ i\\ \, -- / V V\ \ ,/ / / Tv^\ V = 9.8 / / / \ / / / Tx > \^ V= = 4. 62 t I / / / / vS^ S -6- >// A / ^>^ - J^ X kxVJ b^^ y y / ^ r^ .-- ^ 4 = 2.5^ BACH & ROSERRelation between Pressure, Velocityand Coefficient of Friction — 500 1000 1500 2000 Tangential Tooth Pressures - Lbs.Fig. 27. 2500 3000 was established. The mechanism being set in motion by hand,weights were added to the cord on the worm drum until a con-stant speed of rotation could be maintained. On substituting heavier weights, it was found that a greaterweight was needed to keep the wheels in motion, and, severalobservations being thus made, a number of values w^ere obtainedfor the weight necessary to maintain uniform motion withdifferent degrees of tooth pressure. Plotting these values atordinates, upon tooth pressures as abscissae, it was found that 66 WORM GEARS
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00 ^ EFFICIENCY OF WORM GEARING 67 these fell in a straight line as shown by the line A (Fig. 29)The observed points being TABLE VII Pressures x Load to overcome friction y 2 1b.4 1b.8 1b. 3.754.756.75 It is evident that the loads y are the product of a;X/^ Curves showing Values of jJ- from Observed Friction Readingsfrom Observed Points. V = Xti &. 2y-X=5.5 .. 2XfJi.-x=5.5fi approaches V2 as a Limit as X approaches coH .. CO .. .. « ., .. .. Zero. 7 / 6 3. 3 / ■?. n / f h 01 -) / A 0 V f •m 4o / y / s / 1 ^z \ 2X \ I 1 \ ^ ■—. n 2 4 6 8 10 20 30 Pressure in #iC Fig. 29. 40 50 The equation to a straight line is 2y — x = 5.5.*. 2xfi — x = 5.5 5.5 + x Fig. 29 shows the curve to this equation giving values of /xfor various pressures x, from which we see that 68 WORM GEARS (i approaches . 5 as a limit as x approaches c-oH approaches oo as a Hmit as x approaches o. Turning again to Beauchamp Towers experiments, thecurves in Fig. 30 show the relationship between bearing pres

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