CRANK SHAFT DESIGN
FORGINGCASTINGMANUFACTURING PROCESSDR M VARAPRASADA RAO2Design
of Machine Members
(Crank Shaft & Connecting Rod)
Dr. Manda Varaprasada Rao
2
FORGING
DR M VARAPRASADA RAOForging Vs CastingForgingTotal processes
approximate 16Dimensional consistency andaccuracyReduce mass by
10%Consume less energyProvides longer tool lifesmoother running in
the engineLess cost for > 20,000 piecesHigh production rateLess
time consumesReduce cost about 25%It performed at low
temperature
CastingTotal processes approximate 36Less accuracyMore time
consumingRequired high temperature for meltingLow production
rateDefects such as pin hole, shrinkage, porosity, Rough surface
etc.high cost for >20,000 piecesMore waste of materialsMore
labor costMachining processLow strength
DR M VARAPRASADA RAO
Forging DefectsDR M VARAPRASADA RAO
Design of connecting rodDR M VARAPRASADA RAO
DR M VARAPRASADA RAOManufacturing processMATERIALCUTTING TO
LENGTH OF MATERIALBILLETS HEATINGHOT FORGINGDR M VARAPRASADA
RAOPLERCINGTRIMMINGSHOT BLASTING /SHOT PEENINGMACHINING
DEBURRINGMACHINING OF TOP SURFACEGRINDING THE SIDE FACESDRILLING
THE PISTON ENDBROACHING OF CRANK AND PISTON RODDRILLING OF BOLT
HOLEDRILLING OF HOLEMACHINING OF BOLT HEAD SEATDR M VARAPRASADA
RAOMACHINE FRACTURE SPLITTING GROOVEFRACTURE SPLITTINGASSEMBLY OF
CONNECTING RODMACHININGFINISH GRINDING I=OF SIDE FACESFINAL
DRILLING OF CRANK AND PISTONMILLING OF BEARING OF POSITIONING
GROOVEDR M VARAPRASADA RAOINSERTION OF CRANK END BEARING
SHELLSINSERTION OF SMALL END BEARING BUSHINSPECTIONDR M VARAPRASADA
RAOSelection of materialthe connecting rods are most usually made
ofsteel(for lightness and the ability to absorb high impact at the
expense of durability)titanium(for a combination of lightness with
strength, at higher cost) for high performance engines, or ofcast
ironfor applications such as motor scooters.
DR M VARAPRASADA RAO12 Cutting of materialCut the material a
little greater than the required due to further process heating
billetsBillet is heated in the furnace at 500-600 C
Hot forgingHot forging isdefined as working a metal above its
recrystallization temperature.The main advantage of hot forging is
that as
DR M VARAPRASADA RAO the metal is deformed the strain-hardening
effects are negated by the recrystallization process.
piercing:
DR M VARAPRASADA RAO Trimming:
Shot peening:
Machining:DR M VARAPRASADA RAO Fracture splitting
Assembly
Insertion of bearing shell
DR M VARAPRASADA RAO Insertion of bering bushes
Inspection
DR M VARAPRASADA RAOLimitation of forgingIt must be enviourment
friendlyIt finished product cost must be moderateLimitation of the
mass deviation along the longitudinal axismaterials are generally
less expensive than the materials required for casting. Limited
scrap and rework. Reduced labor costs and lower tooling equipment
expenses than casting
DR M VARAPRASADA RAO
Economic limitationDR M VARAPRASADA RAO
DR M VARAPRASADA RAOCRANK SHAFT DESIGNDesign a side or overhung
crankshaft for a 250 mm 300 mm gas engine. The weight of the
flywheel is 30 kN and the explosion pressure is 2.1 N/mm2. The gas
pressure at the maximum torque is 0.9 N/mm2, when the crank angle
is 35 from I. D. C. The connecting rod is 4.5 times the crank
radiusDR M VARAPRASADA RAOGIVEN DATA.Given : D = 250 mm ; L = 300
mm or r = L / 2 = 300 / 2 = 150 mm ; W = 30 kN = 30 103 N ; p = 2.1
N/mm2, p = 0.9 N/mm2 ; l = 4.5 r or l / r = 4.5DR M VARAPRASADA
RAOHow to Design.Design the crankshaft for the two positions of the
crank 1.when the crank is at the dead centre and 2. when the crank
is at an angle of maximum twisting moment.DR M VARAPRASADA
RAOFORMULE & CONSTANTS FROM DATA BOOK14.4 OF DESIGN DATA BOOK
BY JALALUDDEEN
DR M VARAPRASADA RAODIAMETER = 250 MMDesign of crankshaft when
the crank is at the dead centre.We know that piston gas load-
DR M VARAPRASADA RAO
DR M VARAPRASADA RAOBEARING DESIGN
DR M VARAPRASADA RAOCRANK WEB
DR M VARAPRASADA RAOSHAFT LENGTH & DIAMETER
DR M VARAPRASADA RAOOTHER INFORMATIONCALCULATIONS AS PER DESIGN
DATA BOOKDR M VARAPRASADA RAOCONNECTING ROD DESIGN
DR M VARAPRASADA RAOLOAD & INERTIA FORCE.
DR M VARAPRASADA RAO
DR M VARAPRASADA RAO
DR M VARAPRASADA RAO
