Mechanisms and Machine
Theory
Lei Wang (leo)
College of Electromechanical Engineering
Shenyang Aerospace University
Classroom rules

1. Come to class on time.

Late once, -1
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Absent once, -3

3 times, failed


2. Bring necessary materials for the lessens.
3. Talk only when permitted.
 Rasie hand to ask questions.
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4. No food or drink in the classroom.
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No cellphone call.
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No earphone.
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Do not play with your cellphone or MP3, MP4
 5. Finish your task in time.

Do not cheat
 6. Use polite speech and body language.
Unkind teasing and impolite behavior is
unacceptable.
Kinematics and
Dynamics of Machinery
Design of Machinery
Credit Hours and Arrangement of The Course
Fifty-six hours for the whole course.
Fifty one-hour class instructions. ( In some
important sections, I will arrange some exercises
or assign some homework for you.)
Five-hour experiments. (There are three
experiments. The laboratory is on the third floor
of mechanical building. I will inform you about
the time of experiments ahead.)
One-week course design (We will spend one week
on designing a machine to satisfy the conditions
it requires with the knowledge we have learned
from the course.)
Assessment of the Score:
Final exam: 70%
Experiment: 10%
Attendance, exercises and homework: 20%
Course design:
Excellent, good, medium, pass and
fail.
The objects of this course are mechanisms and
machines, and the contents of this course are
about the basic theoretical problems of design of
mechanisms and machines.
What are mechanisms and machines? What
compose of mechanisms and machines? What
kinds of relationship are between mechanisms and
machines?
There are many kinds of machines in our
daily life, such as washing machine, sewing
machine, computer, bicycle, car, bulldozer,
electric motor, generator motor, internal
combustion engine and so on.
Watch the motion and study the structure
of internal combustion engine first.
Internal combustion engine
1. Cylinder or Frame
2. Piston
3. Coupler
4. Crank
4’. Pinion (four apostrophe)
4”. Flywheel
5. Gear
5’. Inlet cam
5”.Outlet cam
6. Inlet valve
7. Outlet valve
Piston 2
Coupler 3 Crank 4
Pinion 4'
Gear 5
Cam 5'
Follower 6
Frame 1
Frame 1
Frame 1
Cam 5"
Follower 7
Frame 1
Slider-crank mechanism
1
2
3
4
Piston 2
Coupler 3 Crank 4
Pinion 4'
Gear 5
Cam 5'
Follower 6
Frame 1
Frame 1
Frame 1
Cam 5"
Follower 7
Frame 1
Gear mechanism
5
1
4'
Piston 2
Coupler 3 Crank 4
Frame 1
Pinion 4'
Gear 5
Cam 5'
Follower 6
Frame 1
Frame 1
Follower 7
Cam 5"
Frame 1
Cam mechanism
1
6
5'
1. Terminology and
Definitions
1) Machine element
Machine element is the
smallest element of
manufacture and can’t be
divided into a smaller one.
For example, coupler body,
big-end cover, nuts, bolts etc.
We think machine element as
the manufacture unit.
2) Link (Component)
Link is a basic element in
kinematic analysis. It must
move as a whole and has no
relative motion between
machine elements. One link
can be a rigid structure of some
machine elements or only one
machine element. We think
link as the motion unit.
The relationship between link and machine elements.
For example, the coupler
is the rigid assembly of
the coupler body, big-end
cover, nuts, and bolts. The
connection between
machine elements to form
link is rigid and relative
motion is not permitted.
The connection can be
welds, rivets, pins, or nuts
and bolts.
The relationship between a link and machine elements.
The crank 4 or
crankshaft, the pinion
4, the flywheel 4, and
the keys, form another
link.
apostrophe
The relationship between a link and machine elements.
The gear 5, the cam
shaft (including the
two cams 5’ and 5”) ,
and the key form a
third link. apostrophe
3) Mechanism
Mechanism is a system of links which can
transform or transmit force and motion.
1
1
6
2
5
1
3
5'
4
Slider-crank
mechanism
4'
Gear mechanism
Cam mechanism
Piston 2
Pinion 4'
Coupler 3 Crank 4
Gear 5
Cam 5'
Frame 1
Slider-crank
mechanism
Frame 1
Frame 1
Cam 5"
1
2
3
4
Follower 6
Follower 7
1
The function of theFrame
slidercrank mechanism is to
transform the reciprocation
of the piston 2 into the
rotation of the crank 4.
Piston 2
Coupler 3 Crank 4
Frame 1
Pinion 4'
Cam 5'
Gear 5
Frame 1
5
Follower 6
Frame 1
Cam 15"
4'7
Follower
Frame 1
Gear mechanism
The function of the gear
mechanism is to change
the direction and speed of rotation.
Pinion
Pinion4'4'
Gear
Gear55
Cam
Cam5'5'
1
Follower
Follower66
6
Frame
Frame11
Frame
Frame11
Cam
Cam5"5"
Follower
Follower77
Frame
Frame11
5'
Cam mechanism
The function of the cam
mechanism is to transform
the continuous rotation of
the cam into a regular
reciprocation of the
follower.
4) Machine
Machine is a mechanical system which can transmit
or transform energy, materials or information.
Many practical machines contain more than one
mechanism while many simple machines are
composed of only one basic mechanism. The term
machinery is used to cover both mechanisms and
machines.
The study object of this book is machinery.
From electric motor to several mechanism
transmission, the sliding bar shifts to the left
and hold the work through movable claw and
fixed claw. When the sliding bar shifts to the
certain position in the right, the movable claw
is forced to loose the work by the stopper.
Belt Drive Mechanism
Self Loading and
Unloading Machine
Worm and Worm Gear
Drive Mechanism
Cam mechanism
Linkage Mechanism
Machine
Machinery
Mechanism
Machine
Element
Independent Independent
Motion unit Manufactured
unit
Link
2.The Content
Structural analysis
1) Common basic topics in Kinematic analysis
machinery theory
Dynamic analysis
In chapter 2, we will study the structural analysis
of mechanisms, such as the compositions, the
kinematical diagram. In chapter 3, we will study the
kinematical analysis of mechanisms, the position,
velocity and the acceleration. In chapter 9, we will
study the machine balance problem which is caused
by inertia forces from acceleration. In chapter 10, we
will study the speed fluctuation and adjustment.
Linkage mechanism
2) Analysis and synthesis Cam mechanism
of commonly used
mechanisms
Gear mechanism
Intermittent motion mechanism
We cannot study all machines, but we need to
analyze all these basic mechanisms which form
machines, study their characteristics and learn how to
design them.
3) Creative design of mechanism system
We can design a new machine through the
lectotype, combination and variation of mechanisms
to satisfy specific requirements.
Linkage mechanism
Gear mechanism
Cam mechanism
Intermittent motion mechanism
Methods of Learning:
Pay attention to the machine you meet.
Put into more practice. In this course, we
will study the theoretical problems of the
machinery. We must connect the theories
with practical cases.
Organization of the Course:
Class instruction
Class exercises
Homework
Experiment
Course design