KINEMATICS Flashcards
WHat is the mobility equation?
m=3(n-1)-2j1-j2
What is grashoff’s law?
s+l<=p+q
What condition makes a crank rocker?
’s’ is next to base
what condition makes a rocker-rocker?
’s’ is opposite to the base
what condition makes a drag link?
’s’ is base
what is a change point mechanism?
when s+l=p+q
How can you have a triple rocker?
s+l>p+q
WHat is the harmonic equation for rise and return?
- Rise:
- y1=L/2(1-cos(πø/ø1))
- Return:
- y3=L/2(1-cos(π(ø-ø3)/(ø2-ø3)))
WHat is the cycloidal equation for rise and return?
- Rise:
- y1=L[ø/ø1-(1/2π)(sin(2π(ø/ø1)))]
- Return:
- y3=L[(ø-ø3)/(ø2-ø2)-(1/2π)(sin(2π((ø-ø3)/(ø2-ø3))))]
What is the cubic equation for rise and return?
- Rise:
- y1=L[3(ø/ø1)2-2(ø/ø1)3]
- Return:
- y3=L[3((ø-ø3)/(ø2-ø3))2-2((ø-ø3)/(ø2-ø3))3]
Harmonic Max?
y’=Lπ/2ø1
Cycloidal Max?
y’=2L/ø1
Uniform Max?
y’=L/ø1
Cubic Max?
y’=6L/4ø1
What is the minimum follower width?
w=y1‘-y3’
What is the undercutting parameter?
Ro=-(y+y’’)min
When finding the minimum base radius that prevents undercutting remember to…
plug in the values for the thetas at which the function is a minimum! if there is a cos term, it will be negative 1!
What is the equation for uniform rise and return?
- Rise:
- y1=Lø/ø1
-
Return:
- same difference as always
When given the pitch diameter of a worm gear, this represents what?
It is the actual diameter of the worm gear
What is diametral pitch?
P=N/D=π/p
What is circular pitch?
p=2πR/N
What is the module?
m=D/N=p/π
What is the circular pitch equation for helical gears?
pn=ptcosø
pt=is the normal transverse pitch (same as circular pitch)
pn=pitch of the hob
What is normal diametral pitch equal to in helical gears?
Pn=π/pn=π/ptcosø=Pt/cosø
Pt=transverse diametral pitch
What are the two equations that relate lead of a worm to the radius of the attached spur gear?
lead=pxN2
R3=N3px/2π
