ME 563
Introduction to Gearing
Chapter 15
Outline
Major Historical Points in Gearing
Motivation for Gearing
Overview of gear type
Gear nomenclature and equations
Fundamental law of gearing
Conjugate Action
Involute
Kinematics
Internal and External Gear
Automotive Window Drive
(this is actually a cross-helical
gear)
Band Clamps are Worm Drives
Worm Gears Drives
Chapter 15
Use in Toys
Final Drive for Locomotive
Applications
Worm
Motor
Here
Output
Worm Gear
Worm Gears Are Often Used in Motor Drives
Geometr
Gear Kinematics
Chapter 15
1
Collins Gear Errata
Page 625, Equation 15-22:
Remove r from this
equation.
T 2 n
hp
12 33000
Ft r1 2 n1 Ft r2 2 n2
12 33000 12 33000
Page 633, Top of Table 15.8 should read AGMA
Geometry Factor J for Bending of 20 Full .
PV
max
12, 000
psi-ft
, thus
min
P
PV
V
12, 000
24
5, 000 psi
Checking Table 10.1 we see for wood that P max = 2000 psi and thus meets the unit load criterion. Since
L
R
Pd
6, 000
500 3
4.0 inches
then
L
d
4
1.333
3
which meets the guidelines
1
2
L
d
2
Th
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A multileaf simply supported spring is to be designed for the rear
wheels of a 3600 lb truck for which 65% of the vehicle weight is
supported by the rear wheels. The static mid-span deflection of
loading is assumed to be released cyclic loadi
Gear Manufacturing
Besides creating a good gear design it
is important to make sure that you pick
the best manufacturing process for your
application.
Polymeric Gear Manufacture
The books gear manufacturing section doesnt recognize the large
volume of gea
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coefficient of friction is
0.20 .
(A) Assume uniform wear and determine the required axial force for pmax 100 psi , and determine
the torque.
(B) Repeat the process in part (A) assuming a uniform pressure of p 100 psi .
(C) Assume uniform wea
Analysis of Complete Gear Trains (almost)
Analysis of Complete Gear Trains (almost)
The gear train shown is from an automobile.
The number of teeth for each gear is given
below. The wheel has a 28 inch diameter. The
car is moving at 30 mph and the wheels
Roller Chain
Chain Advantages and Disadvantages
Positives:
1. Unsurpassed power to weight ratio.
2. Almost the efficiency of gearing. (>98%)
3. Like belts, a good solution when transmitting torque over a distance.
4. Relatively inexpensive and light weigh
Bevel Gears
Chapter 15
A differential contains at least two sets of bevel gears and
Bevel Gear Force Analysis
either a hypoid or additional bevel gear set.
In spur and helical gears we had a pitch circle. In bevel
gears we have a section of a sphere.
ravg
Belts
Chapter 17
Belts Advantages and Disadvantages
Positives:
1. One of the best power to weight ratios (but less than chains).
2. Almost the efficiency of gearing. (>98%)
3. Good solution when transmitting torque over a long distance.
4. Relatively inex
B a n d B r a k e E xa mp le 2
For the differential band brake shown, the coefficient of friction
between the 25-mm-wide belt and the drum is
0.25 . The drum
rotates clockwise at 300 rpm. The maximum lining pressure is
pmax 0.8 MPa . Determine the brake t