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N.-Y.: The Industrial Press, 1920. — 300 p.
A treatise on the principles, dimensions, calculation and design of spiral and worm gearing, together with the chapters on the methods of cutting the teeth in these types of gears
E-Book Content
SPIRAL
AND WORM
GEARING
SPIRAL AND WORM
GEARING A TREATISE ON THE PRINCIPLES, DIMENSIONS, CALCULATION AND .DESIGN OF SPIRAL AND WORM GEARING, TOGETHER WITH CHAPTERS ON THE METHODS OF CUTTING THE TEETH IN THESE TYPES OF GEARS
COMPILED AND EDITED BY
ERIK OBERG, A.S.M.E. ASSOCIATE EDITOR or
EDITOR OF
AUTHOR OF
"
MACHINERY
MACHINERY'S HANDBOOK
HANDBOOK OF SMALL TOOLS," " SHOP ARITHMETIC FOR THE MACHINIST," "
SOLUTION OF TRIANGLES," " STRENGTH OF MATERIALS," "ELEMENTARY ALGEBRA," ETC.
FIRST EDITION FIFTH PRINTING
NEW YORK
THE INDUSTRIAL LONDON:
PRESS
THE MACHINERY PUBLISHING IQ20
CO., LTD.
COPYRIGHT, 1914
BY
THE INDUSTRIAL PRESS NEW YORK
PREFACE THE manner
For pinion,
To
results are so nearly alike that the previous cal-
may
find the
7
^=
r
28, approximately.
find the lead of the tooth helix, use
Lead Lead
for gear for pinion
= =
3.1416
X X
30
6.928 3.1416 find the addendum, use Rule 7
X X
Rule
cot 60 cot 30
To Addendum = ^ = 0.333 inchTo find the whole depth of tooth space, 2>I 57 = 0.719 inch. Whole depth =
6:
= =
54.38 inches.
37.70 inches.
:
use Rule 8:
o
To Rule
find the
normal tooth thickness at the pitch
line,
use
9:
Tooth thickness =
''
=0.523
inch.
o
To
find the outside diameter, use
For gear, 30 For pinion, 6.928
Rule 10:
+ 0.666 = 30.666 inches. + 0.666 = 7.594 inches.
This concludes the calculations for this example. If it is required that the pitch diameters of both gears be more nearly alike, the
tooth angle of the gear must be decreased, and that of
the pinion increased. Suppose we have a case in which the requirements are the same as in Example i, but it is required that both gears shall have the same tooth angle of 45 degrees. Under these conditions the addendum, whole depth of tooth and normal thickness at the pitch line would be the same, but the other dimensions would be altered as below:
Pitch diameter of gear
=
**
3
Pitch diameter of pinion
-
--
=
X
cos 45
3
X
3
=
21.216 inches.
5
=
cos 45
8.487 inches.
SPIRAL GEARING
8
o Center
,.
,
distance
Number
= 21.216+8.487L =
of teeth for
For gear,
=
^
-
(cos 45
For pinion.
select cutter:
127, approximately,
;
-,
(cos 45
Lead
which to
-^-z 3
=51, approximately.
)
=
of helix for gear
3.1416
= Lead
=
of helix for pinion
Outside diameter of gear Outside diameter of pinion
Examples of the
of Calculations
= =
X
21.216
X
cot 45
66.65 inches.
X
8.487 X cot 45 26.66 inches.
3.1416
=
made
,
.
14.851 inches.
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