vakili. dr behnam sadri (865211018) babak vajdi (865211032) atta sojoodi (865211012) mehdi jebeli...

Nima shamsapourNima shamsapour(865211015)

Navid khakpayNavid khakpay(865211007)

Mehdi jebeliMehdi jebeli

845222017

Atta sojoodiAtta sojoodi(865211012)

Babak vajdiBabak vajdi(865211032)

Behnam sadriBehnam sadri(865211018)

Vakili. Dr

Mechanical Engineering DesignMechanical Engineering Design

:Contents

Preface ……………………………………4 What is a gearbox?………………………5Project description………………………..7Bulky characteristics of gearbox………..8Gear design……………………………….9Shaft design………………………………34Deflection consideration…………………37Bearing selection…………………………41Computer programming…………………54Acknowledgments………………………..55References………………………………..56

Preface:

The present work is a class project of mechanical engineering designThe present work is a class project of mechanical engineering design on Samand’s gearbox. The quad did as much as possible in order toon Samand’s gearbox. The quad did as much as possible in order to analyze ,collect, calculate and present the results. At first we have aanalyze ,collect, calculate and present the results. At first we have a historical vision on gearbox then all the parts of gearbox’shistorical vision on gearbox then all the parts of gearbox’s evaluations (some with more details) will be considered. we haveevaluations (some with more details) will be considered. we have

utilized some CAD soft wares like ANSYS,solidworks , catia &Mdesign utilized some CAD soft wares like ANSYS,solidworks , catia &Mdesign and the programming is MATLAB languageand the programming is MATLAB language..

We are really grateful of Dr.vakili on behalf of the recommendations We are really grateful of Dr.vakili on behalf of the recommendations and hope to satisfy him about the processand hope to satisfy him about the process..

?What is a gearbox

Gears are about as old as any ofGears are about as old as any of

the machinery of mankind. The oldest the machinery of mankind. The oldest machinemachine

is the potter's wheel. At first time over 3000is the potter's wheel. At first time over 3000 years ago primitive gears first meshedyears ago primitive gears first meshed

with each other and transmitted rotary motionwith each other and transmitted rotary motion. . Water wheels were used to convert energy ofWater wheels were used to convert energy of

moving water into energy that would powermoving water into energy that would power

machines. Wooden gears connected watermachines. Wooden gears connected water

wheels to machines that would grind wheatwheels to machines that would grind wheat

and hammer metalsand hammer metals..

A transmission or gear box provides speedA transmission or gear box provides speed

and torque conversion and from a rotatingand torque conversion and from a rotating

power source to another device using gearpower source to another device using gear

ratios. In British English the termratios. In British English the term

TRANSMISSION refers to the whole driveTRANSMISSION refers to the whole drive

train, including gearbox, clutch, prop shafttrain, including gearbox, clutch, prop shaft ), ),

for rear wheel drive), differential and finalfor rear wheel drive), differential and final

drive shafts. The most common use is indrive shafts. The most common use is in

motor vehicals,where the transmissionmotor vehicals,where the transmission

adapts the out put of the internal combustionadapts the out put of the internal combustion

engine to the drive wheelsengine to the drive wheels..

Often, a transmission will haveOften, a transmission will have

multiple gear ratios (or simplymultiple gear ratios (or simply

""gears"), with the ability to switchgears"), with the ability to switch

between them as speed variesbetween them as speed varies . .

This switching may be doneThis switching may be done

manually (by the operator), ormanually (by the operator), or

automatically. Directional automatically. Directional (forward(forward

and reverse) control may also beand reverse) control may also be

provided. Single-ratioprovided. Single-ratio

transmissions also exist, whichtransmissions also exist, which

simply change the speed and simply change the speed and torque (and sometimestorque (and sometimes

direction) of motor outputdirection) of motor output. .

Gearboxes have found use in a wide Gearboxes have found use in a wide variety of different—often variety of different—often stationary

—applications, such as—applications, such as wind turbines..Transmissions are also used in Transmissions are also used in agricultural, , industrial, , construction, , mining and and automotive equipment. In equipment. In addition to ordinary transmission addition to ordinary transmission equipped with gears, such equipped with gears, such equipment makes extensive use of equipment makes extensive use of the the hydrostatic drive and electrical and electrical adjustable-speed drives..

Project description

It is desired to design a gearbox To get this we first anaylzedIt is desired to design a gearbox To get this we first anaylzed the forces and power generated in the internal combustion enginethe forces and power generated in the internal combustion engine then according to the inpute data like the maximum torque and then according to the inpute data like the maximum torque and maximum power gears designed Then by considering the maximum power gears designed Then by considering the shasfts distans and gears diameters the critical gear mated shasfts distans and gears diameters the critical gear mated during the engaging identified Then all diameters of shafts during the engaging identified Then all diameters of shafts were found out It is important to note that we used some steps were found out It is important to note that we used some steps through the shafts inorder to reduce the material used in through the shafts inorder to reduce the material used in manufacturingmanufacturing At last all the bearings were selected for the most criticalAt last all the bearings were selected for the most critical condition and all the data and informations were wrote condition and all the data and informations were wrote besides .the figuresbesides .the figures

Bulky characteristics of gearbox

Total weight 39.15Kg

length420mm

width240mm

height310mm

Occupied volume

0.0312m^3

Approximate cost

195$

Normal distance of

shafts

150(mm)

Upper shaft length

360mm

Lower shaft length

410mm

Distance of gear 5,4

40mm


5mm


20mm

Distance of gear 2,REV

5mm

Distance of gear REV,1

60mm

Gear design

There are some important notes to be informed. First we calculated the There are some important notes to be informed. First we calculated the power generated ,from some principle physics and fluid mechanics. power generated ,from some principle physics and fluid mechanics. During the engaging of the gears to the higher speeds, the power During the engaging of the gears to the higher speeds, the power increases and the torque reduces. For the rear gear we assumed the increases and the torque reduces. For the rear gear we assumed the conditions as well as 1conditions as well as 1sttstt gear,inorder to have the worst situation. the gear,inorder to have the worst situation. the assumption for the overload factor was according to the speed of the assumption for the overload factor was according to the speed of the shaft. when we have low speeds it should be less than 1.5 and when shaft. when we have low speeds it should be less than 1.5 and when the speed increases ,the unbalanced forces increases and the the speed increases ,the unbalanced forces increases and the overload factor shouldn’t be less than 2.The gear strength for live overload factor shouldn’t be less than 2.The gear strength for live assumed 10^8 cycles & the reliability was set 99%.Temperture factor assumed 10^8 cycles & the reliability was set 99%.Temperture factor was not considered. The surface condition factor was almost 1 was not considered. The surface condition factor was almost 1 because of our gear materials. All the gears are from steel but different because of our gear materials. All the gears are from steel but different

hard nesseshard nesses . .

Gear1(pinion):

MMnn 2.52.5

DD 70mm70mm

NN 2424

FF 40mm40mm

MaterialMaterialSt,grade2St,grade2

,,550HB550HB

WW 3000rpm3000rpm

HH 64.5hp64.5hp

WWtt*n*ndd 13128N13128N

nn 2020

3030

KKoo11

SSFF1.21.2

SSHH1.21.2

QQvv88

)more details(

SH948.05.1562

206.04070

115.106.1377.1113128191

2.1SH

SF

0928500

48.088.240

115.106.1377.1113128

2.1SF

Gear1(gear):

MMnn 2.52.5

DD 230mm230mm

NN 8080

FF 40mm40mm


,,550HB550HB

WW 913rpm913rpm

HH 64.5hp64.5hp


nn 2020

3030

KKoo11

SSFF1.41.4

SSHH1.31.3

QQvv88

)more details(

SH965.05.1562

206.04070

115.1047.1377.1113128191

3.1SH

SF

965.0560

52.088.240

115.1047.1377.1113128

4.1SF

Rear gear (pinion):MMnn

2.52.5

DD 70mm70mm

NN 2828

FF 40mm40mm


Carburized & Carburized & hardenedhardened

WW 3000rpm3000rpm

HH 64.5hp64.5hp


nn 2020

00

KKoo1.251.25

SSFF1.51.5

SSHH1.21.2

QQvv88

)more details:(

SH948.01619

01374070

115.1049.1377.125.113128191

2.1SH

SF

0928500

6.3.05.240

115.1049.1377.125.113128

5.1SF

Rear gear (gear):MMnn

2.52.5

DD 230mm230mm

NN 9292

FF 40mm40mm



WW 913rpm913rpm

HH 64.5hp64.5hp


nn 2020

00

KKoo1.251.25

SSFF1.021.02

SSHH1.11.1

QQvv88

)More details(

SH974.01619

01374070

115.104.1377.125.113128191

SF

94.0500

46.05.240

115.104.1377.125.113128

02.1SF

1.1SH

2nd gear (pinion):

WW 3700rpm3700rpm

HH 70hp70hp


nn 2020

3030

MMnn 44

DD 105mm105mm

NN 2222

FF 40mm40mm



KKoo1.51.5

SSFF22

SSHH1.21.2

QQvv88

)more details(

SH948.01619

1.040105

1136.1074.15.15.17700191

2.1SH

SF

976.0500

458.061.440

1136.1074.15.15.17700

2SF

2nd gear (gear):MMnn

44

DD 195mm195mm

NN 4242

FF 40mm40mm



WW 2000rpm2000rpm

HH 70hp70hp


nn 2020

3030

KKoo1.51.5

SSFF22

SSHH1.21.2

QQvv88

)More details(

SH962.01619

1.040105

1136.1079.15.15.17700191

2.1SH

SF

988.0500

488.061.440

1136.1079.15.15.17700

2SF

3rd gear (pinion):MMnn

44

DD 130mm130mm

NN 3030

FF 30mm30mm


450HB450HB

WW 4500rpm4500rpm

HH 80hp80hp


nn 2020

3030

KKoo1.51.5

SSFF22

SSHH1.121.12

QQvv99

)more details(

SH948.01311

112.030130

112.1059.144.15.15845191

2SFSF

976.0430

49.061.430

112.1059.144.15.15845

12.1SH

3rd gear (gear):MMnn

44

DD 170mm170mm

NN 4040

FF 30mm30mm


450HB450HB

WW 3440rpm3440rpm

HH 80hp80hp


nn 2020

3030

KKoo1.51.5

SSFF22

SSHH1.121.12

QQvv99

)more details(

SH954.01321

112.030130

112.1062.144.15.15845191

12.1SH

2SFSF

981.0430

5.061.430

112.1062.144.15.15845

4th gear (pinion):MMnn

44

DD 152mm152mm

NN 3333

FF 30mm30mm


300HB300HB

WW 5300rpm5300rpm

HH 90hp90hp


nn 2020

3030

KKoo22

SSFF1.11.1

SSHH22

QQvv99

)More details(

SH948.0866

674.030152

112.106.132.124775191

SF

976.02.248

48.061.430

112.106.132.124775

2SH

1.1SF

4th gear (gear)MMnn

44

DD 148mm148mm

NN 3232

FF 30mm30mm


300HB300HB

WW 5443rpm5443rpm

HH 90hp90hp


nn 2020

3030

KKoo22

SSFF1.11.1

SSHH22

QQvv99

SH976.0866

674.030152

112.106.132.124775191

)More details(

SF

96.02.248

48.061.430

112.106.132.124775

1.1SF

2SH

5th gear (pinion)MMnn

44

DD 172mm172mm

NN 3838

FF 20mm20mm


350HB350HB

WW 6000rpm6000rpm

HH 100hp100hp


nn 2020

3030

KKoo22

SSFF1.11.1

SSHH2.52.5

QQvv9-109-10

)More details(

SH948.0977

561.020172

112.1039.115.24140191

SF

971.05.221

49.061.420

112.1039.15.24140

2SH

1.1SF

5th gear (gear)

WW 8062rpm8062rpm

HH 100hp100hp


nn 2020

3030

MMnn 44

DD 128mm128mm

NN 2828

FF 20mm20mm


350HB350HB

KKoo2.52.5

SSFF1.11.1

SSHH2.52.5

QQvv9-109-10

)More details(

SH948.0977

561.020172

112.1039.115.24140191

2SH

SF

971.05.221

49.061.420

112.1039.15.24140

1.1SF

Shaft design:

Now it is the time to design the shafts. The most important note is the Now it is the time to design the shafts. The most important note is the gears weight. For the upper shaft, we assumed concentrated weight at gears weight. For the upper shaft, we assumed concentrated weight at the center of the gears but at the lower shaft because of their large the center of the gears but at the lower shaft because of their large size, we assumed uniform distributed force. The other note is the size, we assumed uniform distributed force. The other note is the steps. During the calculation, we saw that there are some parts that steps. During the calculation, we saw that there are some parts that can be manufactured with less diameters. saw we considered some can be manufactured with less diameters. saw we considered some steps and used 3mm fillet radius. The fatigue failure was one of the steps and used 3mm fillet radius. The fatigue failure was one of the important factor. this is stated after evaluating the other parameters important factor. this is stated after evaluating the other parameters like critical frequency and defelction.the SODERBERG was the relation like critical frequency and defelction.the SODERBERG was the relation for the fatigue failure. The deflection would result in larger diameters, for the fatigue failure. The deflection would result in larger diameters,

so we used one more bearing in each shaft to reduce the deflectionso we used one more bearing in each shaft to reduce the deflection . .The calculations resulted in the critical condition when engaging the rear The calculations resulted in the critical condition when engaging the rear or the 1or the 1stst gear. so we examined the gear 4 in order to reject it as the gear. so we examined the gear 4 in order to reject it as the bad condition then we solved the problem on the base of rear and 1bad condition then we solved the problem on the base of rear and 1stst geargear..

Upper shaft:

Diameters Diameters from left to from left to

rightright

45mm50mm36mm

MaterialMaterial1030HR1030HR1030HR

Critical situationCritical situation is when rearis when rear

gear is engagedgear is engaged..

Lower shaft:

Diameters from Diameters from left to rightleft to right

34mm47mm50mm

MaterialMaterial1045 CD1045 CD1045 CD

Critical situationCritical situation is when rearis when rear

gear is engagedgear is engaged

Deflection considerations(ANSYS)

Other gears just Other gears just vanishedvanished..

ModelingModeling

Showing Showing the fillets of the fillets of

the stepsthe steps..

Uniform load Uniform load distribution of distribution of

the gearthe gear..

Stress Stress distributiondistribution..

))before middle before middle bearingbearing((


))after middle after middle bearingbearing((

Bearing selection:

We were supposed to select 4 bearings ,two for the upper shaft We were supposed to select 4 bearings ,two for the upper shaft and two for the lower shaft. But when evaluating the and two for the lower shaft. But when evaluating the deflections we saw that it is worth to try the 3deflections we saw that it is worth to try the 3rdrd bearing for each bearing for each shaft and reduce the undesirable deflection which can cause shaft and reduce the undesirable deflection which can cause force increased during the engaging. So we did it andforce increased during the engaging. So we did it and

According to the critical forces, we selected the suitable bearing According to the critical forces, we selected the suitable bearing from SKF online bearing selection for a long life.Ofcourse in from SKF online bearing selection for a long life.Ofcourse in bearing selection, its diameters ,mass and cost were bearing selection, its diameters ,mass and cost were consideredconsidered.

Upper shaft (right side):

Upper shaft (Left side):

Upper shaft (middle)

Lower shaft( right side)

Lower shaft( left side)

Lower shaft (middle)

Computer programming:

In order to computerize the evaluations ,we wrote the In order to computerize the evaluations ,we wrote the program which gets some input data like program which gets some input data like m,Np,Ng,Wt,speed and some others and predicts the m,Np,Ng,Wt,speed and some others and predicts the coefficient of safety for pitting and bending.Ofcourse coefficient of safety for pitting and bending.Ofcourse we are really grateful of Mr.milanchiyan for his prior we are really grateful of Mr.milanchiyan for his prior program which we have extended it .There is an program which we have extended it .There is an animation which shows the operationanimation which shows the operation..

Acknowledgment:

At first we really thanks GOD which provided the At first we really thanks GOD which provided the conditions in order to work on the project as much conditions in order to work on the project as much as possible. Then we are really grateful of our wise as possible. Then we are really grateful of our wise master,Dr.vakili on behalf of the recommendations. master,Dr.vakili on behalf of the recommendations. We really thanks from TAKARAN CO(ISACO bureau We really thanks from TAKARAN CO(ISACO bureau in TEHARAN) , our dear engineer ,Mr.Ghorbani and in TEHARAN) , our dear engineer ,Mr.Ghorbani and our classmate Mr.milanchiyan.We hope to develop our classmate Mr.milanchiyan.We hope to develop

our performance in future works.enshalahour performance in future works.enshalah.….…

References:

1.Budynas,Nisbett,shigley’s mechanical engineering design,6th,7th,8th edition,Mc graw Hill,

افزار . 2 نرم توسط طراحی و رحیمیان،تحلیل محمد ANSYS دکتر

در. 33 در. طراحی نارنجی ANSYSANSYSطراحی مثلث کتابهای جمشیدی،مجموعه نارنجی ،نیما مثلث کتابهای جمشیدی،مجموعه ،نیما

44..www.SKF.COMwww.SKF.COM

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vakili. dr behnam sadri (865211018) babak vajdi (865211032) atta sojoodi (865211012) mehdi jebeli...

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