Chap 3. Graphical Linkage Synthesis (3장 . 도해 기구 합성 )
Most engineering design practice involves a combination of synthesis and analysis.
Most engineering courses deal primarily with analysis techniques for various
situations. However, one can not analyze until it has been synthesized into existence.
Many machine design problems require the creation of a device with particular motion characteristics. Perhaps you need to move a tool from position A to position B in a particular time interval. Perhaps you need to trace out a particular path in space to insert a part into assembly.
We will now explore some simple synthesis techniques to enable you to
create potential linkage design solutions for some typical kinematic
applications.
Crank-Shaper Quick-Return Mechanism
(Excerpted from the textbook)
3.6 커플러 곡선 (Coupler Curves )
커플러 곡선
• 커플러 링크가 그리는 곡선.
• 다양한 형태의 곡선 가능. m 2 3
n/21
링크 수
m차 곡선
(Excerpted from the textbook)
3.6 커플러 곡선 (Coupler Curves )
Film-advance mechanism
고정
고정
Crank
Rocker Coupler
(Excerpted from the textbook)
3.6 커플러 곡선
Automotive suspension
1
2
3 4
The coupler curve of the wheel
center is nearly a straight line over small vertical displacement required.
This is desirable as the idea is to keep the tire perpendicular to the ground for best traction under all cornering and attitude changes of the car body.
(Excerpted from the textbook)
3.8 직선운동기구 (Straight-Line Mechanisms)
Watt straight-line linkage
L1=4 L2=2 L3=1 L4=2 AP=0.5
(Excerpted from the textbook)
3.8 직선운동기구 (Straight-Line Mechanisms)
Roberts straight-line linkage
L1=2 L2=1 L3=1 L4=1 AP=1 BP=1
(Excerpted from the textbook)
3.8 직선운동기구 (Straight-Line Mechanisms)
Chebyschev straight-line linkage
L1=2 L2=2.5 L3=1 L4=2.5 AP=0.5
(Excerpted from the textbook)
3.8 직선운동기구 (Straight-Line Mechanisms)
L1= L2 L3= L4
L5= L6 = L7 = L8
1 3 2
4 5
6
7 8
Peaucellier exact straight-line linkage
Peaucellier was a French army captain and military engineer who first proposed his
“compas compose” or compound compass in 1 8 6 4 b u t r e c e i v e d n o i m m e d i a t e r e c o g n i t i o n . T h e B r i t i s h - A m e r i c a n mathematician, James Sylvester, reported on it to the Atheneum Club in London in 1874. He observed that the perfect parallel motion of Peaucellier looks so simple and moves so easily that people who see it at work almost universally express astonishment that it waited so long to be discovered.”
A
C B
D
P E
DOF = 3(8-1)-2(10) = 1
F
G Q
(Excerpted from the textbook)
3.8 직선운동기구 (Straight-Line Mechanisms)
L1= L2 L3= L4
L5= L6 = L7 = L8
1
2 3
4 5
6
7 8
Peaucellier exact straight-line linkage
Peaucellier was a French army captain and military engineer who first proposed his
“compas compose” or compound compass in 1 8 6 4 b u t r e c e i v e d n o i m m e d i a t e r e c o g n i t i o n . T h e B r i t i s h - A m e r i c a n mathematician, James Sylvester, reported on it to the Atheneum Club in London in 1874. He observed that the perfect parallel motion of Peaucellier looks so simple and moves so easily that people who see it at work almost universally express astonishment that it waited so long to be discovered.”
A
C B
D
P
E
AB x AP = (AF-BF) x (AF+BF)
F= AF
2-BF
2= (AD
2-DF
2) – (BD
2-DF
2)
= AD
2-BD
2Constant !
= L
42-L
62a AP = L
42-L
62AB = L
42-L
622L
1cos a AP cos a = L
42-L
622L
1AP cos b
(Excerpted from the textbook)
3.8 직선운동기구 (Straight-Line Mechanisms)
(Excerpted from the textbook)
3.8 직선운동기구 (Straight-Line Mechanisms)
3.8 직선운동기구 (Straight-Line Mechanisms)
• Hart investor (Exact)
• Evans linkage (approximate)
(Excerpted from the textbook)
3.9 일시정지기구 (Dwell Mechanisms)
입력운동 ( = 0 ) 출력운동 ( = 0 )
(Excerpted from the textbook)
3.9 일시정지기구 (Dwell Mechanisms)
입력운동 ( = 0 ) 출력운동 ( = 0 )
20 180 320 360
크랭크 각도 로커 각도
80
80
• 근사적 운동
(Excerpted from the textbook)
3.9 일시정지기구 (Dwell Mechanisms)
(Excerpted from the textbook)
