Download MEG 373 Kinematics and Dynamics of Machines

University of Bahrain
College of Engineering
Department of Mechanical Engineering
MEG 373 Kinematics and Dynamics of Machines
(Chapter 7) Gears
Student Name:
Student No.:
Problem 1:
Figure1 shows a simple gear train. If the input is
provided by gear A and the output is taken off the
shaft of gear E, what is the ratio and the sign of
out in in terms of the number of teeth on the
gears.
Dr. Mostafa S. Habib
MEG373 Kinematics and Dynamics of Machines
Page 1
University of Bahrain
College of Engineering
Department of Mechanical Engineering
MEG 373 Kinematics and Dynamics of Machines
(Chapter 7) Gears
Student Name:
Student No.:
Problem 2:
The compound gear train shown in Figure2 is attached
to a motor that drives gear A at in clockwise as viewed
from below. What is the expression for the angular
velocity of gear H in terms of the number of teeth on
the gears? What is the direction of rotation of gear H as
viewed from below?
Dr. Mostafa S. Habib
MEG373 Kinematics and Dynamics of Machines
Page 2
University of Bahrain
College of Engineering
Department of Mechanical Engineering
MEG 373 Kinematics and Dynamics of Machines
(Chapter 7) Gears
Student Name:
Student No.:
Problem 3:
Gear A of the gear train in Fig.3 is driven at 200 rpm
clockwise as viewed from below. The shafts of all gears
are located in grounded bearings. Determine G , K and
I given the number of teeth on each gear as indicated in
the figure. Determine the direction of rotation of these
three gears as viewed from the right.
Dr. Mostafa S. Habib
MEG373 Kinematics and Dynamics of Machines
Page 3
University of Bahrain
College of Engineering
Department of Mechanical Engineering
MEG 373 Kinematics and Dynamics of Machines
(Chapter 7) Gears
Student Name:
Student No.:
Problem 4:
The gear train shown in Fig.4 is arranged to feed
lumber between the two 6-in. diameter rollers (R)
into a cutting blade for ripping the lumber. The
blade is being directly driven at 500 rpm. A power
take-off, which consists of the belt system shown,
drives the rollers for the purpose of feeding the
stock. Determine the speed of the stock in ft/min
and the direction of stock movement.
Dr. Mostafa S. Habib
MEG373 Kinematics and Dynamics of Machines
Page 4
University of Bahrain
College of Engineering
Department of Mechanical Engineering
MEG 373 Kinematics and Dynamics of Machines
(Chapter 7) Gears
Student Name:
Student No.:
Problem 5:
Design an ordinary gear train to couple the two shafts in Fig.5 so that the driver will
rotate at 30 rpm and the follower at 21,000 rpm in the directions indicated. Design
must be based on catalog gears of from 12 to 25 teeth listed every integer, and from
26 to 60 teeth listed every other integer. Prepare a drawing of the train arrangement
and label each gear.
D  30rpm
F  21, 000rpm
Dr. Mostafa S. Habib
MEG373 Kinematics and Dynamics of Machines
Page 5
University of Bahrain
College of Engineering
Department of Mechanical Engineering
MEG 373 Kinematics and Dynamics of Machines
(Chapter 7) Gears
Student Name:
Student No.:
Problem 6:
Figure 6 shows a three-speed transmission with
the drive shaft rotating in place at 450 rpm
carrying the cluster of gears A, B, and C. The
follower shaft is splined and may be shifted along
its axis by means of the shift link to bring gears E,
G, and H into contact with the gears on the drive
shaft. Design the transmission to produce speeds
of 150, 350, and 550 rpm, and describe how
motion is transmitted in these three speeds. Gear
teeth are to be kept within the limits of from 10 to
80 teeth.
Dr. Mostafa S. Habib
MEG373 Kinematics and Dynamics of Machines
Page 6
University of Bahrain
College of Engineering
Department of Mechanical Engineering
MEG 373 Kinematics and Dynamics of Machines
(Chapter 7) Gears
Student Name:
Student No.:
Problem 7:
For each planetary gear train in Figure7, determine the ratio indicated in the following
list: (a) By the formula method.
(b) By the tabular method.
(c) By the instant-center method:
Fig. 7(a): 2 3
Fig 7(b): 3 4
Fig 7(c): 2 3
Fig 7(d): 2 4
Fig 7(e): 3 4
Dr. Mostafa S. Habib
Fig 7(f): 4 5
MEG373 Kinematics and Dynamics of Machines
Page 7
University of Bahrain
College of Engineering
Department of Mechanical Engineering
MEG 373 Kinematics and Dynamics of Machines
(Chapter 7) Gears
Student Name:
Student No.:
Problem 8:
(a) Determine the number of teeth on gear E of the gear train hoist in Figure 8
which yields a gear reduction between B and A of B A  25 , given NB = 20,
NC = 80, and ND = 30.
(b) Determine the numerical value of the mechanical advantage of this gear train
hoist, W/Fin , assuming no losses.
Dr. Mostafa S. Habib
MEG373 Kinematics and Dynamics of Machines
Page 8
University of Bahrain
College of Engineering
Department of Mechanical Engineering
MEG 373 Kinematics and Dynamics of Machines
(Chapter 7) Gears
Student Name:
Student No.:
Problem 9:
The sun gear B of Figure.9 rotates at 100 rpm CW as viewed from the right.
Determine the angular velocity and direction of G as viewed from the bottom.
A = arm
B = 24 teeth
C = 60 teeth
D = 18 teeth
E = 102 teeth (fixed)
F = 25 teeth
G = 50 teeth
Dr. Mostafa S. Habib
MEG373 Kinematics and Dynamics of Machines
Page 9