lecture 2 mechanisms & machines · gears, pulleys, & sprockets these three power train...
TRANSCRIPT
![Page 1: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/1.jpg)
Lecture 2Mechanisms & Machines
![Page 2: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/2.jpg)
The Six Simple Machines
Lever Wheel andAxle Pulley
![Page 3: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/3.jpg)
The Six Simple MachinesInclined Plane ScrewWedge
![Page 4: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/4.jpg)
Simple machines:Gears
![Page 5: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/5.jpg)
Why does a wind turbine need a
gearbox?
![Page 6: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/6.jpg)
By the way…• Where is the safety harness• No fall protection• No eye or hearing protection• This subcontractor would be
removed from the site & possibly terminated
![Page 7: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/7.jpg)
![Page 8: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/8.jpg)
This person has a fun job
![Page 9: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/9.jpg)
The gearboxes are big and they weigh a lot
![Page 10: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/10.jpg)
![Page 11: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/11.jpg)
Gears, Pulleys, & SprocketsThese three power train elements transfer energy through rotary motion.
• Change the speed of rotation• Change the direction of rotation• Change the amount of torque available to do work
![Page 12: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/12.jpg)
Gears
A gear train is made when two or more gears are meshed
A gear train is a mechanism used for transmitting rotary motion and torque through interlocking teeth.
Driver gear causes motion
Motion is transferred to the driven gear
![Page 13: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/13.jpg)
Gears
Mated gears always turn in opposite directions.An Idler Gear allows the driver and driven gears to rotate in the same direction.Mated gears always have the same size teeth (diametric pitch).
![Page 14: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/14.jpg)
GearsThe rpm of the larger gear is always slower than the rpm of the smaller gear.Gears locked together on the same shaft will always turn in the same direction and at the same rpm.
![Page 15: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/15.jpg)
Gear RatiosVariables to know
n = number of teethd = diameter
ω = angular velocity (speed)τ = torque
** Subscripts in and out are used to distinguish between gears **
4”
nin=din =ωin =τin =
62in.40rpm40 ft-lb
nout =dout =ωout =τout =
124in.20rpm80 ft-lb
![Page 16: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/16.jpg)
Gear Ratios
out out outin
in in out in
n dGR1 n d
τω= = = =
ω τ
Equations to knowGR = Gear Ratio of the gear set
lbftlbft
−−
4080
rpmrpm
2040
.2
.4inin
6122
1
![Page 17: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/17.jpg)
Gear Ratios
= =out
in
nGR1 n
What is the gear ratio between gear A and B?
=5 .42
12 1What is the gear ratio between gear B and C?
=20 45 1
What is the gear ratio between gear C and D?
=12 .620 1
= =out
in
nGR1 n
= =out
in
nGR1 n
Input gear
![Page 18: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/18.jpg)
Gear Ratios
• • =0.6 0.42 41 1 1
What is the TOTAL gear train gear ratio?
What would the total gear ratio be if the last gear had 40 teeth?
• • =0.6 0.42 8 21 1 1 1
11
If gear A and D were directly connected to each other, what would the resulting gear ratio be?
=20 120 1
or = = =out
in
nGR 40 21 n 20 1
= =out
in
nGR1 n
Idler gears don’t affect GR!
![Page 19: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/19.jpg)
Compound Gear Trains
The two middle gears share a common axle, so they rotate at the same speed.
This allows the final gear to rotate slower and produce more torque than if it were connected only to the driver gear.
Driver
![Page 20: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/20.jpg)
Here, the two middle gears are connected to a common axle and rotate together
50 T40 T
20 T 10 T
40 410 1
=
AB
C
D
What is the gear ratio between gear A and B?
50 2.520 1
=
What is the gear ratio between gear C and D?
What is the gear ratio of the entire gear train?4 2.5 101 1 1
• =
1= =out
in
GR nn
1= =out
in
GR nn
![Page 21: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/21.jpg)
out out outin
in in out in
n dGR1 n d
τω= = = =
ω τ
![Page 22: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/22.jpg)
Pulley and Belt Systems
out outin
in out in
dd
τω= =
ω τ
.2
.6inin
rpmrpm
1030
d = diameter ω = angular velocity (speed) τ = torque
out
lbft
lbft
−
−
3118
55
![Page 23: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/23.jpg)
What is the purpose/effect of each of these pulleys below?
![Page 24: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/24.jpg)
Do you see something wrong with this pulley/belt arrangement below?
![Page 25: Lecture 2 Mechanisms & Machines · Gears, Pulleys, & Sprockets These three power train elements transfer energy through rotary motion. ... d = diameter. ω= angular velocity (speed)](https://reader030.vdocuments.us/reader030/viewer/2022040301/5e71ffc77eee163927101b4a/html5/thumbnails/25.jpg)
Sprocket and Chain Systems
out out outin
in in out in
n dn d
τω= = =
ω τ
1122
.5.1.3
inin
n = number of teeth d = diameter ω = angular velocity (speed) τ = torque
3in.
out1.5in.in
rpmrpm
4590
lbftlbft
−−
60120