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TERM PAPER

KINEMATICS OF MACHINE

MEC 202

TOPIC: Study the cam prof!e" u"ed # ma#ufactur#$ mach#e"

Date of allotment: 14/10/2010

Date of Submission: 15/11/2010

Submitted to: Submitted by:

Mr. Kamlesh Mishra Name: Sachin ana

!De"tt. #f Mechanical$ e%. No: 10&04&'(

Section: K4&01

oll No: K 4&01 )*5


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ACKNO%&E'(EMENT

+o many indi,iduals - am indebted %ood counsel and assistance in

,arious ays in this res"ect one of my sincerest thans toMr. Kamlesh

Sir of o,ely rofessional 3ni,ersity ha%ara for their ind

coo"eration and able %uidance.

- oe a dee" sense of ine"tness of my "ureness that has been source of

ins"iration in e,ery or of my life.

- dee"ly e"ress our ine"tness and thans to all my faculty member and

friends for there in ,aluable %uidance hich enable me to brin% out this

"roect in a "resentable manner.

Sachin


3/14

A)STRACT

+he term "a"er "resents the analysis of ,arious cam "rofiles used in

manufacturin% machines. -t focuses mainly on the ty"es of cam and its

folloers and ho are they classified accordin% to their sha"e manner

of mo,ement and motion. -t also focuses on the %ra"hical re"resentation

of the cam "rofile i.e. ho are they constructed and hat are the

"rocedure to construct a cam "rofile and ho they can be used in a

machine.


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INTRO'*CTION

6 cam is a mechanical member used to

im"art desired motion to a folloer by direct

contact. 6 cam is a rotatin% or slidin% "iece

in a mechanical lina%e used es"ecially in

transformin% rotary motion into linear

motion or ,ice7,ersa. +he cam may be

rotatin% or reci"rocatin% hereas the

folloers may be rotatin% reci"rocatin% or

oscillatin%. -t is often a "art of a rotatin%

heel !e.%. an eccentric heel$ or shaft !e.%.

a cylinder ith an irre%ular sha"e$ that

stries a le,er at one or more "oints on its

circular "ath. +he cam can be a sim"le tooth

as is used to deli,er "ulses of "oer to a

steam hammer for eam"le or an eccentric

disc or other sha"e that "roduces a smooth

reci"rocatin% !bac and forth$ motion in the

folloer hich is a le,er main% contact

ith the cam.

+he cam can be seen as a de,ice that

translates from circular to reci"rocatin% !or

sometimes oscillatin%$ motion. 6 common

eam"le is the camshaft of an automobile

hich taes the rotary motion of the en%ineand translates it into the reci"rocatin%

motion necessary to o"erate the intae and

ehaust ,al,es of the cylinders. +he

o""osite o"eration translation of

reci"rocatin% motion to circular motion is

done by a cran. 6n eam"le is the

cranshaft of a car hich taes the

reci"rocatin% motion of the "istons and

translates it into the rotary motion necessary

to o"erate the heels. 8ams can also be

,ieed as information7storin% and

7transmittin% de,ices.

6 cam 9 the folloer combination belon%

to the cate%ory of hi%her "airs. Necessary

elements of a cam mechanism are

6 dri,er member non as the cam

6 dri,en member called the folloer

6 frame hich su""orts the cam 9 %uides

the folloer

6n early cam as built into ;ellenistic

ater7dri,en automata from the *rd century

)8. +he use of cams as later em"loyed by

6l7


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automata. +he cam and camshaft a""eared

in >uro"ean mechanisms from the 14th

century.

+he binary cam is a desi%n for the "ulley

system of a com"ound bo. 8rai% ?ehle

director of research and de,elo"ment at

)otech 6rchery recei,ed a "atent for the

desi%n on December 11 200'. )otech

started e@ui""in% its bos ith the ne cam

desi%n in the 2005 model year.

+he binary cam is described as a modified

tin cam setu" here each cam is sla,ed to

the other ,ia a loo" of strin% connectin% the

to cams. +his is contrasted ith a ty"ical

tin cam setu" here the ends of the

bostrin% are "hysically anchored onto each

of the bo limbs.

6s a tin cam system relies on each cam

rotatin% inde"endently based solely on the

force of the strin% and the resistance of the

bo limbs bein% absolutely symmetrical

there is room for a tin cam system to Alose

tuneA throu%h ear and tear strin% stretch

or ust %eneral a%e. +he effect of a detuned

tin cam bo is that the to cams rotate out

of sync ith each other causin% the

bostrin% to accelerate in to alternatin%

directions u"on release. +his causes a

number of ad,erse conse@uences the most

ob,ious bein% unsteady arro fli%ht.

+he binary cam o,ercomes this by Bsla,in%B

each cam to the otherC as one cam is unable

to rotate ithout the direct e@ui,alent action

of the other the to rotate in near "erfect

synchroni=ation ith any "ossible

differences in rotation automatically

correctin% themsel,es as the shot cycle is

com"leted.

T+PES OF CAMS

8ams are classified accordin% to

1$ Sha"e

2$ olloer mo,ement 9

*$ Manner of constraint of the folloer.

Accord#$ to Shape:,


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-. %ed$e / F!at Cam": 6 ed%e

%enerally has a translational motion. +he

folloer can either translate or oscillate.

S"rin% is used to maintain the contact

beteen the cam 9 the folloer. +he

cam is stationary 9 the folloer causes

the relati,e motion of the cam.

2. Rada! / '"c Cam": 6 cam in hich

the folloer mo,es radially from the

centre of rotation of the cam is non as

a radial or a disc cam.

. Spra! Cam": 6 s"iral cam is a face cam

in hich a %roo,e is cut in the form of a

s"iral. +he s"iral %roo,e consists of teeth

hich mesh ith a "in %ear folloer.

4. Cy!#drca! Cam": 6 cylinder hich

has a circumferential contour cut in the

surface rotates about its ais.

5. Co#1u$ate Cam": 8onu%ate cams are a

double7disc cam the to discs bein%

eyed to%ether 9 are in constant touch

ith the to rollers of a folloer.

6. (!ooda! Cam": 6 %loboidal cam can

ha,e to ty"es of surfaces con,e or

conca,e.


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7. Spherca! Cam": -n a s"herical the

folloer oscillates about an ais

"er"endicular to the ais of rotation of

the cam.

Accord#$ to fo!!o3er mo4eme#t

1. R"e,Retur#,R"e 5R,R,R6: -n this

there is alternate rise 9 return of the

folloer ith no "eriods of dells.

+he folloer has a linear or an

an%ular dis"lacement.

2. '3e!!,R"e,Retur#,'3e!! 5',R,R,

'6: -n such a ty"e of cam there is

rise 9 return of the folloer after a

dell.

3. '3e!!,R"e,'3e!!,Retur#,'3e!!

5',R,',R,'6: -t is the most idely

used ty"e of cam. +he dellin% of

the cam is folloed by rise 9 dell

9 subse@uently by return 9 dell.

Accord#$ to Ma##er of Co#"tra#t of the

Fo!!o3er

1. Pre,!oaded "pr#$ cam: -s used for

the "ur"ose of ee"in% the contactbeteen the cam 9 the folloer.

2. Po"t4e,dr4e cam: 8onstant touch

beteen the cam 9 the folloer is

maintained by a roller folloer

o"eratin% the %roo,e of cam.

3. (ra4ty cam: -f the rise of the cam

is achie,ed by the risin% surface ofthe cam 9 the return by the force of

%ra,ity or due to the ei%ht of the

cam the cam is non as the %ra,ity

cam.

T+PES OF FO&&O%ERS

8am folloers are classified accordin% to

the

1. Sha"e

2. Mo,ement 9

*. ocation of line of mo,ement.

Accord#$ to "hape

1. K#fe,ed$e Fo!!o3er: Sim"le in

construction. ;oe,er its use is

limited as it "roduces a %reat ear of

the surface at the "oint of contact.

2. Ro!!er Fo!!o3er: Eidely used cam

folloer 9 has a cylindrical roller

free to rotate about a "in oint. 6t


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lo s"eed the folloer has a "ure

rollin% action but at hi%h s"eeds

some slidin% also occurs.

Accord#$ to Mo4eme#t

1. Recprocat#$ Fo!!o3er: 6s the

cam rotates the folloer

reci"rocates or translates in the

%uides.

2. O"c!!at#$ Fo!!o3er: +he folloer

is "i,oted at a suitable "oint on the

frame 9 oscillates as the cam maesthe rotary motion.

Accord#$ to &ocato# of e of

Mo4eme#t

1. Rada! Fo!!o3er: +he folloer is

non as a radial folloer if the line

of mo,ement of the folloer "asses

throu%h the center of rotation of the

cam.

2. Off"et Fo!!o3er: -f the line of

mo,ement of the roller folloer is

offset from the center of rotation of

the cam the folloer is non as

offset folloer.

CAM PROFI&ES

DESIGN PRINCIPLE

+he method termed inematic in,ersions is

commonly used in cam "rofile desi%n. or

eam"le in a dis cam ith translatin%

folloer mechanism the folloer translates

hen the cam turns. +his means that the

relati,e motion beteen them is a

combination of a relati,e turnin% motion and

a relati,e translatin% motion. Eithout

chan%in% this feature of their relati,e

motion ima%ine that the cam remains fied.

No the folloer "erforms both the relati,e

turnin% and translatin% motions. Ee ha,e

in,erted the mechanism

Cam Nomenclature


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F )a"e crc!e: -t is the smallest circle

tan%ent to the cam "rofile !contour$

dran from the center of rotation of

a radial cam.

F Trace po#t:-t is the reference "oint

on the folloer to trace the cam

"rofile such as the nife7ed%e

folloer and the center of the roller

of a roller folloer.

Ptch cur4e: -t is the cur,e dranbythe trace "oint assumin% that the cam

is fied and the trace "oint of the

folloer rotates around the cam.

F Pre""ure a#$!e: -t re"resents the

stee"ness of the cam "rofile it is the

an%le beteen the normal to the

"itch cur,e at a "oint and the

direction of folloer motion. -t

,aries in ma%nitude at all instants of

folloer motion.

F Ptch po#t: -t is the "oint on the

"itch cur,e at hich "ressure an%le

is maimum.

F Ptch crc!e: -t is the circle "assin%

throu%h the "itch "oint and

concentric ith the base circle.

F Prme crc!e: +he smallest circle

dran tan%ent to "itch cur,e is

non as the "rime circle.

F A#$!e of A"ce#t 5out"tro7e6: -t is

the an%le turned by cam durin% the

time of rise of folloer.

F A#$!e of '3e!!: -t is the an%le

turned by cam hile the folloer

remains stationary at the hi%hest or

loest "osition.

F A#$!e of de"ce#t 5Retur# "tro7e$:

-t is the an%le turned by cam hen

folloer returns to its initial "osition.

F A#$!e of acto#: -t is the an%le

turned by cam durin% be%innin% of

rise and the end of return of the

folloer.

HI(H,SPEE' CAMS

6 real folloer alays has some mass 9

hen multi"lied by acceleration inertia

force of the folloer is obtained. +his force

is alays felt at the contact "oint of the

folloer ith the cam surface 9 at the

bearin%s. 6n acceleration cur,e ith abru"t


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chan%es eerts abru"t stresses on the cam

surfaces 9 at the bearin%s accom"anied by

detrimental effects such as surface ear 9

noise. 6ll this may lead to an early failure

of the cam system. +hus it is ,ery im"ortant

to %i,e due consideration to ,elocity 9

acceleration cur,es hile choosin% a

dis"lacement dia%ram.

-n lo7s"eed a""lications cam ith

discontinuous acceleration characteristics

may not sho any undesirable characteristic

but at hi%her s"eeds such cams are certainly

bound to sho the same. +he hi%her the

s"eed the hi%her is the need for smooth

cur,es. 6t ,ery hi%h s"eeds e,en the er is

made continuous as ell.

&A+O*T OF CAM PROFI&ES

6 cam "rofile is constructed on the "rinci"le

of inematic in,ersion i.e. considerin% the

cam to be stationary 9 the folloer to be

rotatin% about it in the o""osite direction of

the cam rotation.

G-NH>S-#N

(raphca! Repre"e#tato# of Cam Prof!e

For the ca"e of recprocat#$ 7#fe,

ed$e fo!!o3er

Step-: di,ide the dis"lacement7dia%ram

6bscissa into a number of se%ments.

Step2: di,ide the "rime circle into

8orres"ondin% se%ments.

Step: transfer distances by means of

di,iders from the dis"lacement dia%ram

directly onto the cam layout to locate the

corres"ondin% "ositions of the trace "oint.


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Step8:dra a smooth cur,e throu%h these

"oints. +he cur,e is ust the re@uired cam

"rofile.

For the case of reciprocating

offset roller follower

6s shon in abo,e fi%ure the dis"lacement

dia%ram of the folloer is %i,en sIs

!J$.8onstruct the "late cam "rofile

Step-:construct the "rime circle ith radius

r0.


12/14

Step2:construct the offset circle ith radius

e@ual to the amount of offset e.

Step: di,ide the dis"lacement7dia%ram

abscissa into a number of se%ments.

Step8: di,ide the offset circle into

corres"ondin% se%ments and assi%n station

numbers to the boundaries of these

se%ments.

Step9:construct lines tan%ent to the offset

circle from these station di,idin% the "rime

circle into corres"ondin% se%ments.

Ste"(: transfer distances by means of

di,iders from the dis"lacement dia%ram

directly onto the cam layout to locate the

corres"ondin% "ositions of the trace "oint

alays measurin% outard from the "rime

circle.

Ste"': dra a smooth cur,e throu%h these

"oints. +he cur,e is ust the re@uired cam

"rofile.

*N'ERC*TTIN(

Sometimes it may ha""en that the "rime

circle of a cam is "ro"ortional to "ro,ide a

satisfactory "ressure an%le still the folloer

may not be com"letin% the desired motion.

+his can ha""en if the cur,ature of the "itch

cur,e is too shar".

-t can easily be obser,ed that the

cam cur,e loo"s o,er itself in order to

reali=e the "rofile of the "itch cur,e. 6s it is


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im"ossible to "roduce such a cam "rofile

the result is that the cam ill be undercut 9

become a "ointed cam. No hen the roller

folloer ill be made to mo,e o,er this

cam it ill not be "roducin% the desired

motion.

-t may be obser,ed that the cam ill

be "ointed if the radius of the roller is e@ual

to the radius of cur,ature of the "itch cur,e.

+hus to minimum radius of cur,ature of the

cam "rofile the radius of cur,ature of the

"rime circle must alays be %reater than that

of the radius of the roller.

CAMPRO EN(INE

+he 8am"ro en%ine is the first automoti,e

en%ine e,er de,elo"ed to%ether ith otus

by the Malaysian carmaer roton. +he

name 8am"ro is short for 8am rofilin%.

+his en%ine "oers the roton en72 the

roton Satria Neo the roton Eaa 8am"ro

the roton ersona as ell as rotonBs future

models. +he 8am"ro en%ine is aimed to

sho rotonBs ability to mae their on

en%ines that "roduce %ood "oer out"ut and

meet neer emission standards.

6ll 8am"ro en%ines incor"orate

dri,e7by7ire technolo%y !s"ecifically

electronic throttle control$ for better

res"onse eliminatin% the need for friction7

%eneratin% mechanical lina%es and cables.

REFERENCE

1. htt"://.%oo%le.co.in/ima%esL

hlIen9@Icam"rofiles9umI19ieI

3+7

9sourceIuni,9eiI2yOc+MeN#M

Eecf)5MP9saIO9oiIima%eQresultQ%rou"9ctItitle9resnumI*9,ed

I08DPPs6P6%9biI10249bih

I(0(

2. htt"://.technolo%ystudent.com/c

ams/cam2.htm

*. htt"://hdabob.com/8am

R20rofiles.htm

4. htt"://.mar"oss.com/"roduct."h

"/en%/camshaftQ"rofileQautomaticQin

s"ection

5. htt"://.technolo%ystudent.com/c

ams/cam2.htm

(. htt"://.ma"lesoft.com/a""licatio

ns/,ie.as"LS-DI*25'

'. htt"://.cs.cmu.edu/ra"id"roto/

mechanisms/ch"t(.html

. htt"://.ise%ee.com/hat7is7a7

camshaft.htm

&. htt"://mech"roects.blo%s"ot.com/20

0/01/technical7terms7used7in7cam7

dia%ram.html


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