DTS PROCEDURE.docx

8/10/2019 DTS PROCEDURE.docx

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DESIGN PROCEDURES

1

DESIGN OF TRANSMISSION SYSTEMS

UNIT IDESIGN PROCEDURE FOR FLAT BELT DRIVE:-

STEP: 1 Calculation of pulley diameters:

Velocity ratio (i) = =

Where N1= Driver pulley speed in rpm.N2 = Driven pulley speed in rpm.D = Diameter of driven pulley.d = Diameter of driver pulley.

STEP: 2 Calculation of the design power in KW:

Design KW = ()

Rated Kw is given in the problem.

Load correction factor (Ks) Taken from PSG DDB Page No: 7.54

Arc of contact factor (Ka) Taken from PSG DDB Page No: 7.54 for that we

much calculated the

= 180

X 60

If C is not Given Assume 1 meter ( 1000mm)

Small pulley factor (Kd) Taken from PSG DDB Page No: 7.62.

STEP: 3 Selection of Belt:

Select a belt referring from PSG DDB Page No: 7.54.

STEP: 4 Load rating correction:

Load rating at V m/s = Load rating at 10 m/s From DDB Page No: 7.54.

Velocity of belt (V) =

m/sec


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DESIGN PROCEDURES

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STEP: 5 Determination of belt width:

Width of the belt =

No of Piles Taken from PSG DDB Page No: 7.52. Plies based on the Belt

Speed in m/sec.

STEP: 6 Determination of Pulley Width:

Based on Belt width Ref table From PSG DDB Page No: 7.54.

STEP: 7 Calculation of length of the belt:

Referring from PSG DDB Page No: 7.53. Which type of drive givencorresponding Drive formula used (Ex. Open belt drive)


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DESIGN PROCEDURES

3


UNIT IDESIGN PROCEDURE FOR FLAT BELT PULLEY:-

STEP: 1 Calculate the Dimensions of the Pulley:

v=

m/sec

STEP: 2 Calculate the Width of the Pulley():

P = (T1-T2) v

Tc = mv2

Where

m = Mass of the belt per meter length

m = Density X Volume

Density of leather belt is 1000Kg/m3

T = X Area of belt (Area = b X t)T1 = T Tc

After finding the width of the Pulley find out the thickness of the Pulley

rim also Ref PSG DDB Page No: 7.57.

STEP: 3 Calculate the Dimensions of arms:

Number of arms (n) Ref PSG DDB Page No: 7.56.

Cross section of the arm Ref PSG DDB Page No: 7.56.

Arms taper Ref PSG DDB Page No: 7.56.

Radius of the cross section of arms

STEP: 4 Calculate the Dimensions of Hub:

Diameter of the Hub (d1)

d1 = 1.7 To 2.0 times of Diameter of the Shaft (d2)

Length of the Hub () Where = Width of the PulleyRef PSG DDB Page No: 7.56.

Crown of the Pulley Ref PSG DDB Page No: 7.55.


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DESIGN PROCEDURES

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UNIT IDESIGN PROCEDURE FOR V - BELT DRIVE:-

STEP: 1 Selection of belt section:

Select the belt cross section depending on the power to be transmitted.

Ref PSG DDB Page No: 7.58

STEP: 2 Selection of pulley diameters (d and D)

Select the small pulley diameter (d) from Ref PSG DDB Page No: 7.56.

Using speed ratio (i) find the larger diameter (D) for std Diameter

Ref PSG DDB Page No: 7.54.

STEP: 3 Selection of Center distance (C):

Using speed ratio (i) find the (C) Ref PSG DDB Page No: 7.61

STEP: 4 Determine the nominal pitch length:

Referring from PSG DDB Page No: 7.53. Which type of drive given

corresponding Drive formula used (Ex. Open belt drive)

STEP: 5 Selection of various modification factors:

1. Length correction factor (Fc)

Referring from PSG DDB Page No: 7.587.60

2.

Correction factor for arc of contact (Fd)

= 180 X 60 Referring from PSG DDB Page No: 7.68.3. Service factor (Fa)

Referring from PSG DDB Page No: 7.69. Its taken from load transmitted

which depends upon the characteristics of the driving and driven units.


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DESIGN PROCEDURES

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STEP: 6 Determination of Maximum power capacity:

Referring from PSG DDB Page No: 7.62. Its taken from belt cross section symbol

S = Belt speed, m/sec.

de= dp X Fb

dp = Pitch diameter of the smaller pulley, mm.

Fb = Small diameter factor to account for variation of arc contact, Ref

Page No. 7.62.

STEP: 7 Determination of No. of Belt (nb)

Referring from PSG DDB Page No: 7.70.

STEP: 8 Calculation of actual centre distance:

Referring from PSG DDB Page No: 7.61.


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DESIGN PROCEDURES

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UNIT IDESIGN PROCEDURE FOR CHAIN DRIVE:-

STEP: 1 Selection oF Transmission Ration

STEP: 2 Selection of No. of Teeth on the Drivers Sprocket (Z1)

Assume the z value based on the transmission ratio (i)

STEP: 3 Determine No. of Teeth on the Driven Sprocket (Z2)

Z1, Z2ODD Number for uniform wear

STEP: 4 Selection of Standard Pitch (P)

Centre distance a = (3050) P Ref PSGDDB Page No: 7.74.

STEP: 5 Selection of Chain

Ref PSGDDB Page No: 7.73.

STEP: 6 Calculation of total load on the driving side of the chain (PT)

(i) Tangential Force (PT)

Ref PSGDDB Page No: 7.78

(ii) Centrifugal tension (PC)

PC = mv2

Where, m = mass per length Ref PSGDDB Page No: 7.717.73


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DESIGN PROCEDURES

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(iii) Tension due to sagging (PS):

PS= k.w.a

Where, k = Co-efficient of Sag, Ref PSGDDB Page No: 7.78

w = Weight of the chain per metre = m. g Ref PSGDDB Page No: 7.717.73

a = Centre distance in metre.

STEP: 7 Calculation of service factor (ks)

ks= k1,k2,k3,k4,k5,k6

Load factor k1 Ref PSGDDB Page No: 7.76Factor for distance regulation k2Ref PSGDDB Page No: 7.76

Factor for centre distance of sprockets k3 Ref PSGDDB Page No: 7.76Factor for the position of the sprockets, k4 Ref PSGDDB Page No: 7.77Lubrication factor, k5 Ref PSGDDB Page No: 7.77Rating factor k6 Ref PSGDDB Page No: 7.77

STEP: 8 Calculation of design load:

Design load = PT X ks

STEP: 9 Calculation of working factor of safety (FSw)

FSw =

Breaking load (Q) -- Ref PSGDDB Page No: 7.717.73

STEP: 10 Check for factor of safety:

Recommended value (FSw) check to n. For n Ref PSGDDB Page No: 7.77

If the design is not safe means 1) Increase the Pitch of chain. 2) Choose Duplex or

Triplex chain.


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DESIGN PROCEDURES

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STEP: 11 Check for Bending stress in the roller (

Where, A Area of the roller, Ref PSGDDB Page No: 7.717.73

By using smaller sprocket speed and pitch the allowable bearing stress is

compared to induced stress. The induced stress is less than allowable bearing stress

hence the design is safe.

To find allowable stress Ref PSGDDB Page No: 7.77

STEP: 12 Calculation of actual length of chain (L):

Ref PSGDDB Page No: 7.75, using those formulas to calculate the (L).

STEP: 13 Calculation of exact centre distance (a):

Ref PSGDDB Page No: 7.75, using those formulas to calculate the (a).

STEP: 14 Calculation of sprocket diameters:

Ref PSGDDB Page No: 7.78, using those formulas to calculate the (d1& d01)


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DESIGN PROCEDURES

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UNIT IDESIGN PROCEDURE FOR WIRE ROPE:-

STEP: 1 Selection of suitable wire rope:

STEP: 2 Calculations of design load:

Design Load: Load to be lifted X Assumed factor of safety

Assume factor of safety 2 to 2.5 times, the factor of safety Ref PSGDDB Page No: 9.1

STEP: 3 Selection of wire rope diameter (d):

Ref PSGDDB Page No: 9.59.6. From the pages select the wire rope

diameter and breaking strength.

STEP: 4 Calculating of shave diameter (D):

(For velocity upto 50m/min)

Ref PSGDDB Page No: 9.1

STEP: 5 Selection of the area of useful cross-section of the rope (A):

Type ofconstruction

Metallic area ofrope A, mm2

6 X 7

6 X 19

6 X 37

0.38 d2

0.4 d2

0.4 d2

STEP: 6 Calculation of wire diameter (dw)

STEP: 7 Selection of weight of rope (Wr)

Ref PSGDDB Page No: 9.59.6


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STEP: 8 Calculation of various loads:

1. Direct load Wd = W + Wr

2. Bending load Wb = X A3. Acceleration load due to change in the speed of hoisting,

Wa =

; a =

4. Starting or stopping load:a) Starting load, Wst= 2 X Wd

b)When there is slackin the rope

Wst = X A

STEP: 9 Calculation of effective loads:

1. Effective load on the rope during normal working, Wen= Wd + Wb

2. Effective load on the rope during acceleration of the load Wea= Wd + Wb+ Wa

3. Effective load on the rope during starting, West= Wb + Wst

STEP: 10 Calculation of working factor of safety (FSw)

FSw= for Breaking load Ref PSGDDB Page No: 9.59.6

STEP: 11 Check for safe design.

Compare the calculate working factor of safety (FSw) with the recommended

factor safety n.

i.e., (FSw) > n then the design is safe.

(FSw) < n the the design is not safe. So choose some other rope

with greater breaking strength or increase the number of ropes.

STEP: 12 Calculation of number of ropes:

Number of ropes =


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DESIGN PROCEDURES

11


UNIT IIDESIGN PROCEDURE FOR SPUR GEAR-

BASED ON LEWIS EQUATION METHOD

STEP: 1 Selection of materials:

If not given, select a suitable pinion and gear materials

Ref PSGDDB Page No: 1.40 and 8.4

STEP: 2 Calculations of Z1and Z2:

If not given, assume number of teeth on pinion Z1 18 (Prefer 20)

Z2= i X Z1, where igear ratio.

STEP: 3 Calculations of Tangential load on tooth (Ft):

Ft= Koin Newton

V = Pitch Velocity = dN / 60, in m/sec

Ko= Service / Shock factor

STEP: 4 Calculations of Initial dynamic load (Fd):

Fd=

in Newton

Cv= Velocity factor assume value 1020 m/sec

Cv=

;

Types of load Ko

Steady

Light shock

Medium shock

Heavy shock

1.0

1.25

1.5

2.0


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DESIGN PROCEDURES

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STEP: 5 Calculations of beam Strength (Fs):

Fs= . m. b . [b] . y

Where, m = Module in mm,

B = Face width in mm, initially assume b = 10 X module.[b] = Design bending stress or allowable static stress.y = Form factor, Ref PSGDDB Page No. 8.53.

STEP: 6 Calculations of module (m):

Equating FsFd. find the module.

STEP: 7 Calculations of b, d and v.:

Find the face width (b) = 10m

Find the pitch circle diameter (d1) = z.m

Find the pitch line velocity (v) = d1N1/60

STEP: 8 Recalculations of the beam strength (Fs) :

Fs= . m. b . [b] . y

Using the above step b,m values find the new beam strength.

STEP: 9 Calculations of accurate dynamic load (Fd):

Fd = Ft+ FI

= Ft+

Where, c = deformation factor, Ref PSGDDB Page No. 8.53

Ft= P/v (neglecting service factor K0)

STEP: 10 Checking of beam strength:

Compare Fdand Fs

If Fd Fs, hence the design is safe.

If Fd Fs, hence the design is not safe, 1. Reduce the deformation factor, 2.

Select the precision gear 3.Increase the face width.


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DESIGN PROCEDURES

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STEP: 11 Calculations of Maximum wear load (Fw):

Fw = d1X b X Q X Kw

Ratio factor (Q) =

=

Kw = load stress factor

STEP: 12 Check for wear:

Fd< Fw , then the design is safe and satisfactory.

STEP: 13 Calculation of basic dimensions of pinion and gear:

Ref PSGDDB Page No: 8.82 and find the following parameters

Module, centre distance, height factor, bottom clearance, tooth depth, pitch

circle diameter, tip diameter and root diameter.


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DESIGN PROCEDURES

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UNIT IIDESIGN PROCEDURE FOR SPUR GEAR-

STEP: 1 Calculation of gear ratio (i):

=


If not given the gear materials, Ref PSGDDB Page No: 8.28.5

STEP: 3 Calculation of gear life:

N = N1 .T. 60

Where, N1= Pinion speed in rpm.T = Working life hours. If not given the gear life, assume 20,000hrs)

STEP: 4 Calculation of Initial torque [Mt]:

[Mt] = Mt . K. Kd. other details Ref PSGDDB Page No: 8.15

STEP: 5 Calculation of Eeq, [b] and [c]: For EeqRef PSGDDB Page No: 8.14

For [b] Ref PSGDDB Page No: 8.19 For [c] Ref PSGDDB Page No: 8.16

STEP: 6 Calculation of Centre distance (a)

For (a) Ref PSGDDB Page No: 8.13

For Ref PSGDDB Page No: 8.14

STEP: 7 Selection of number of teeth on Pinion (Z1) and Gear (Z2)

Assume Z1 18; Z2= i X Z1


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DESIGN PROCEDURES

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STEP: 8 Calculations of module (m)

for standard module. Ref PSGDDB Page No 8.2 selects choice I

STEP: 9 Revision of centre distance (a)

a = ( )

STEP: 10 Calculations of b,d,v, and p

Calculate face width (b) = . aCalculate the pitch diameter of the pinion (d1) = m. Z1

Calculate the pitch line velocity (v) = d1N1 /60

Calculate the value of (p) =

STEP: 11 Selection of quality of gears:

Using pitch line velocities select the quality of the gear. Ref PSGDDB Page No.8.3

STEP: 12 Revision of design torque [Mt]:

Revise K: Using the calculated value of p, revise the load concentrationfactor. Ref PSGDDB Page No. 8.15.

Revise K

d

: Using the selected quality of gear and calculated pitch line

velocity, revise of dynamic load factor (Kd) Ref PSGDDB Page No. 8.16.

Revise [M

t

]: Using the revised value of K and Kd, find the revised design

torque.

STEP: 13 Check for bending stress b:

Ref PSGDDB Page No. 8.13.

STEP: 14 Check for Wear strength c:



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DESIGN PROCEDURES

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STEP: 14 Calculation of basic dimensions of pinion and gear.




If the design is not satisfactory

b

> [

b

] and

c

>

[

c

], then increase the

module or face width value or change the gear material.


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DESIGN PROCEDURES

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UNIT IIIDESIGN PROCEDURE FOR HECIAL GEAR-

BASED ON LEWIS EQUATION METHOD


If not given, select a suitable pinion and gear materials

Ref PSGDDB Page No: 1.40 and 8.4

STEP: 2 Calculations of Z1and Z2:

If not given, assume number of teeth on pinion Z1 18 (Prefer 20)

Z2= i X Z1, where igear ratio.

STEP: 3 Calculations of Tangential load on tooth (Ft):

Ft= Koin Newton

V = Pitch Velocity = dN / 60, in m/sec

Ko= Service / Shock factor

STEP: 4 Calculations of Initial dynamic load (Fd):

Fd=

in Newton

Cv= Velocity factor assume value 1020 m/sec

Cv=

;

Types of load Ko

Steady

Light shock

Medium shock

Heavy shock

1.0

1.25

1.5

2.0


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DESIGN PROCEDURES

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STEP: 5 Calculations of beam Strength (Fs):

Fs= . m. b . [b] . y

Where, m = Module in mm,

B = Face width in mm, initially assume b = 10 X module.[b] = Design bending stress or allowable static stress.y = Form factor, Ref PSGDDB Page No. 8.53.

STEP: 6 Calculations of normal module (mn):

Equating FsFd. find the module.

STEP: 7 Calculations of b, d and v.:

Find the face width (b) = 10 mn

Find the pitch circle diameter (d1) =

Find the pitch line velocity (v) = d1N1/60

STEP: 8 Recalculations of the beam strength (Fs) :

Fs= . m. b . [b] . y

Using the above step b,m values find the new beam strength.

STEP: 9 Calculations of accurate dynamic load (Fd): cos2

Fd = Ft+ FI

= Ft+

Where, c = deformation factor, Ref PSGDDB Page No. 8.53

Ft= P/v (neglecting service factor K0)

STEP: 10 Checking of beam strength:

Compare Fdand Fs

If Fd Fs, hence the design is safe.

If Fd Fs, hence the design is not safe, 1. Reduce the deformation factor, 2.

Select the precision gear 3.Increase the face width.


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STEP: 11 Calculations of Maximum wear load (Fw):

Fw =

Ratio factor (Q) =

=

Kw = load stress factor

STEP: 12 Check for wear:

Fd< Fw , then the design is safe and satisfactory.

STEP: 13 Calculation of basic dimensions of pinion and gear:





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DESIGN PROCEDURES

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UNIT IIDESIGN PROCEDURE FOR HELICAL GEAR-

STEP: 1 Calculation of gear ratio (i):

=




N = N1 .T. 60




STEP: 5 Calculation of Eeq, [b] and [c]: For EeqRef PSGDDB Page No: 8.14




For Ref PSGDDB Page No: 8.14




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DESIGN PROCEDURES

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STEP: 8 Calculations of normal module (mn)

For standard module. Ref PSGDDB Page No 8.2 selects choice I

mn=

cos

STEP: 9 Revision of centre distance (a)

a =

X( )

mn

STEP: 10 Calculations of b,d1,v, and p

Calculate face width (b) = . a

Calculate the pitch diameter of the pinion (d1) = Z1

Calculate the pitch line velocity (v) = Calculate the value of (p) =


Using pitch line velocities select the quality of the gear.

Ref PSGDDB Page No.8.3


Revise K: Using the calculated value of p, revise the load concentration

factor. Ref PSGDDB Page No. 8.15.

Revise K

d



Revise [M

t

]: Using the revised value of K and Kd, find the revised designtorque.




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DESIGN PROCEDURES

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b

> [

b

] and

c

>

[

c




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DESIGN PROCEDURES

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UNIT IIIDESIGN PROCEDURE FOR BEVEL GEAR-

STEP: 1 Calculation of gear ratio (i) pitch angles.:

=

Pitch angle:

=




N = N1 .T. 60




STEP: 5 Calculation of Eeq, [b] and [c]:

For EeqRef PSGDDB Page No: 8.14

For [b] Ref PSGDDB Page No: 8.19

For [c] Ref PSGDDB Page No: 8.16

STEP: 6 Calculation of Cone distance (R)

For (a) Ref PSGDDB Page No: 8.15 For Ref PSGDDB Page No: 8.14


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DESIGN PROCEDURES

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Virtual number of teeth: =

; =

STEP: 8 Calculations of module (mt)


STEP: 9 Revision of cone distance (R)

R =0.5 mt

STEP: 10 Calculations of b,mav, d1avand y

Calculate face width (b) =

Calculate average module (mav) = mt

Calculate the pitch diameter of the pinion (d1av) = mav. Z1

Calculate the pitch line velocity (v) = d1avN1 /60

Calculate the value of (y) =


Using pitch line velocities select the quality of the gear. Ref PSGDDB Page No.8.3


Revise K: Using the calculated value of p, revise the load concentrationfactor. Ref PSGDDB Page No. 8.15.

Revise K

d



Revise [M

t

]: Using the revised value of K and Kd, find the revised design

torque.


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DESIGN PROCEDURES

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b

> [

b

] and

c

>

[

c




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DESIGN PROCEDURES

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UNIT IIIDESIGN PROCEDURE FOR WORM GEAR-


If not given the gear materials.

Sl. No ConditionMaterials

Worm Worm Wheel1. Light loads and low speed Steel Cast Iron

2. Medium service conditionsCase hardened

steel of BHN 250Phosphor Bronze

3. High speeds, heavy loads withshock conditions

Hardened

molybdenum steelor chrome

vanadium steel

Phosphor bronze(chilled)

STEP: 2 Calculation of Initial design wheel torque [Mt]


STEP: 3 Selection of Z1& Z2

For = 80% If Z1is not given Ref PSGDDB Page No:8.46Z2= i X Z1,

STEP: 4 Selection of [b] and [c]:



Assume q = 11 (its q can vary from 8 to 13)



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DESIGN PROCEDURES

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STEP: 6 Calculate the axial module (mx)

mx=


STEP: 7 Revise centre distance (a)

a = 0.5 mx(q + Z2)

STEP: 8 Calculations of d1, v, and vsCalculate the pitch diameter of the pinion (d1) = q x mx & d2= Z2X mx

Calculate the pitch line velocity (v) =

Calculate the value of () =

Calculate Sliding velocity (vs) =

STEP: 9 Recalculate the design contact stress [c]

Using Sliding velocity select the quality of the gear. Ref PSGDDB Page No.8.45.


For v2 < 3 m/sec, Kd= 1


b=

yv = Form factor based on virtual number of teeth,

Ref PSGDDB Page No: 8.18.

Zv=

yv = Ref PSGDDB Page No. 8.52.


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DESIGN PROCEDURES

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STEP: 13 Check for efficiency:

actual= 0.95 X

Ex: 0.05 vs= 1.432 m/secand bronze wheel, from Graph.

STEP: 14 Calculation of cooling area required (A)

( 1) X Input power = KtXA (tota)

STEP: 15 Calculation of basic dimensions of the worm and worm gear


Axis module, Number of stars, Number of teeth on worm wheel,

Length of worm, Centre distance, Face width, Height factor, Bottom clearance,

Pitch diameter, Tip diameter & Root diameter.


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DESIGN PROCEDURES


UNIT IVDESIGN PROCEDURE FOR GEARBOX-

STEP: 1 Selection of spindle speeds:

=

STEP: 2 Draw the Ray diagram

STEP: 3 Draw the Kinematic arrangement

STEP: 4 Calculation of number of teeth on all gears.

STEP: 5 Selection of material.

STEP: 6 Calculation of module.

STEP: 7 Calculation of centre distance

Ex:

a1=

X m ; a2=

X m ; ; a3=

X m

STEP: 8 Calculation of face width: b = X mSTEP: 9 Calculation of Length of shaft.

STEP: 10 Design of shaft.

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DTS PROCEDURE.docx