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PROJECT #5 DESIGN OF A TRANSMISSION SYSTEM FOR CHAIN CONVEYOR 1: Electric Motor 2: V-Belt Drive 3: Speed reducer 4: Flexible coupling 5: Chain Conveyor Design Parameters: CHAPTER I.. 1

FACULTY OF MECHANICAL ENGINEERING

PROJECT TRANSMISSION SYSTEM

Instructor:

Student’s name:

Mo le a eo Ho WLLL wonye

PROJECT #5 DESIGN OF A TRANSMISSION SYSTEM FOR CHAIN CONVEYOR

1: Electric Motor 2: V-Belt Drive 3: Speed reducer

4: Flexible coupling 5: Chain Conveyor

Design Parameters:

CHAPTER I MOTOR SELECTION AND

1.1.1 Select efficiency of system

- Transmission Efficiency:

- Including :

: Efficiency of worm gear

: Efficiency of helical gears (the helical gears in the reducer) : Efficiency of V-belt drive

with: +: the preliminary power for motor

1.1.3 Determine the number of revolutions of motor

_The number of revolutions of conveyor : (rpm)

_Select the transmission ratio is:

with: +: the ratio of the helical gear 1-stage reducer (

+: the ratio of the belt drive (

_The preliminary number of revolutions of motor:

(rpm)

1.1.4 Select Electric Motor

with +: the power of electric motor

+: the number of revolutions of motor

T 1 io distributi

_Transmission ratio of the system:

_Select the transmission ratio for worm gear 1-stage reducer : _ Select the transmission ratio for V-belt drive:

1.1.5 Working power on each shaft

1.3.2 Number of revolutions on each shaft

1.3.3 Torque on each shaft

CHAPTER II CALCULATE AND DESIGN MACHINE ELEMENTS

2.1 Belt drive design:

2.1.1 Select type of belt and pulleys’s diameter

- Base on figure 4.1- page 59- [2] with the power and

, V belt type B is selected with: , ,, , ,

- Select the standard

- Verify the linear velocity

= = satisfy the condition

- Diameter of the driven pulley:

=>

= Base on standard =

- The real transmission ratio of belt drive:

- Error of transmission ratio

= Satisfy the condition

2.1.2 Calculate preliminary center distance

- The center distance a need to satisfy the condition:

=>

=>

- The belt length :

=

- Base on standard, select

- Varify revolutions per second :

=

= Satisfy the condition

- Recalculate the center distance a :

= Satisfy the condition

2.1.5 Calculate number of belt

- Contact angle correction factor :

- Belt length correction factor

-Number of belt correction factor :

- Operation correction factor :

-.Select and with and

-Number of belts:

Select z = 3

2.1.6 Determine the force on each shaft

- Initial tension force :

- Tension force on each belt:

2.1.8 Stress in belt drive and service life

-Maximum belt stress in belt drive:

Mpa

-Service life:

2.2 WORM GEAR DESIGN

2.2.1 Preliminary slip velocity

Preliminary slip velocity

With , select accuracy class 7

- => Select BrSiNiP as the material for worm wheel

- Select 40Cr steel with hardness of > 45 HRC as the material of worm with 2.2.2 Allowable stresses

Contact stress:

Bending stress:

Select:

Number of teeth of worm wheel

Select diameter factor

=> Select

2.2.4 Preliminary estimation of efficiency

2.2.5 Estimation of center distance

Where:

X : ratio between mean and max torques

: deformation factor of worm

Module:

Select

Accurate center distance:

2.2.6 Parameters of worm drive

Recalculate allowable contact stress:

: tensile ultimate stress of material

: Slip velocity factor

With : Equivalent operating cycles

2.2.8 Equivalent number of teeth

Verification of bending stress in worm

Equivalent moment of inertia of worm

Deflection of worm

With Satisfy condition

2.3 Shaft design:

2.3.1 Select material:

Shaft I:

Force acting on belt drive

Force acting on gear drive in gear box :

Shaft IT:

2.3.3 Shaft preliminary calculation:

Shaft diameter (10.3)- page 353- [1]:

- Allowable torsional stress for 45-steel:

- Shaft II:

We have : T; = 28772.4 N.mm

Shaft II:

- We have:

The force equilibrium equation on y axis is:

The moment equilibrium equation in x-z plane at location A:

The force equilibrium equation on x axis is:

Shaft I is made of Normalized 45-steel

Allowable bending stress

According to moment distribution diagram, the most critical position is section B:

Shaft diameter at section B is determined:

(formula 10.15-page 359-[1])

So, we select standard diameter

Shaft II

The force equilibrium equation on y axis is:

The moment equilibrium equation in x-z plane at location A:

The force equilibrium equation on x axis is:

Shaft II is made of Normalized 45-steel

Allowable bending stress

According to moment distribution diagram, the most critical position is section B:

Shaft diameter at section B is determined:

(formula 10.15-page 359-[1])

So, we select standard diameter

2.4.7 Varify the condition for designing shafts

2.4.7.1 Varify for safety factor

Safety factor regarding to fatigue life (formula 10.18-page 360-[1]):

which:

: allowable safety factor, ; we select

: safety factor regarding to bending and torsion stress ( 10.19, 10.20-page 360-[1])

with

, : fatigue limits of material

, : magnitude and mean values of bending stress (10.22-[1]):

are defined as the following equation table (10.6)[1]:

: factors representing effect of average stress to fatigue

with the table page 361 -[1], for C45 steal select and

concentrating stress factor, which is following table (10.5 , 10.6 , 10.7 , 10.8 )-[1]

: dimension factor can be determined by the table 10.3- page 362-[1]

: surface hardening factor base on table 10.4-page 362-[1]

Varify at the most critical position , we have:

2.4.1 Shaft I

- Rotational speed : n: = 3000 (rpm)

- Radial bearing force A (Formula 11.26- page 397-[1])

-Radial bearing force C

- Axial force:

Select tapperd roller bearing with contact angle

With tapperd roller bearing:

Because

Select : Service factor

V : Factor of rotating ring ( inner ring rotate)

From the result above , we realize that bearing at section C has greater load so we calculate base

- Radial bearing force A (Formula 11.26- page 397-[1])

-Radial bearing force C

Bearing type Principat dimensions Basic load ratings Speed ratings

Designation Bore The Widen Dynamic Static fost tie Limiting Catalogue

We have :

We have:

Select : Service factor

V : Factor of rotating ring ( inner ring rotate)

Dynamic equivalent bearing load :

For radial and radial-axial load carrying bearings

From the result above , we realize that bearing at section A has greater load so we calculate base

on bearing at A

Working life of bearing based on fatigue life :

Bearing satisfy dynamic loading condition