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Subject: Machine Elements II

Academic Year: 2018 (Spring Semester)

Lecturer: Dr. Antonios Lontos

Assignment No 1: Design of a 2-stage Gear Box

A draft drawing of a gear reducer is shown in the figure. The input shaft 1 is rotated by an electric

motor. The electric motor and the input shaft are connected using couplings. The power to be

transmitted by the motor is ...(a)… KW. The rotational speed of the shaft 1 is …(b)… rpm.. The total

ratio of the gear reducer is approximately 12. The speed reducer consists of 2 pairs of gears. For the

first gear it is known that the pressure angle is Φ=200, N1= …(c)… teeth, m=…(d)…. The distance L1

is given (L1= …(e)….). Consider as allowable contact stress (σc, allowable) equal to σuts. The maximum

contact stress will be σc < σuts. The diameter of shafts 1, 2 and 3 should be from 25 to 40 mm.

Answer the following questions:

Part A: Calculations

1. Specify the full geometry of each gear. Design each different gear with all the details.

2. Determine all forces, torques and bending stresses (Lewis eq.). Determine the contact stress (σc).

Select the material of each gear in order to have SF>2.5.

Part B: Drawings and Assembly

1. Make the construction drawings of all different parts (2D).

2. Design the coupling that connects the electric motor with shaft 1. Make detail drawings.

3. Design the speed reducer with all gears in cross section view.

4. Design shafts 1, 2 and 3 with all components and explain in details how to make the assembly

(Short assembly manual and service manual).

5. Design the gear box in 3D.

6. Use safety covers where needed.

VERY IMPORTANT NOTES

* Estimate all dimensions that are not given.

* Useful documents: Cover for Assignment, Drawing template example

* You must submit one hard copy and one pdf file with all calculations and drawings

* Example for the pdf file name “13000_Georgiou Georgios (Assignment 1)”

Assignment No.1

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Gear box - draft drawing

Assignment No.1

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HOW TO SEND YOUR ASSIGNMENT BY EMAIL

Name of the pdf file:

6820_Georgiou Georgios (Assignment 1)

Email to send your Assignment:

Email1: lontosantonios@gmail.com

How to send your assignment using your email:

Dear Sir,

I send you the Assignment 1 for the course AMEM316.

Regards,

Georgiou George

Reg. Number: 3767

Email example:

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Table 1:

Table 2:

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Table 3:

Table 4:

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Electric motor

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