# Gearbox Design | Machine Design- Interview Question and Answers

Gearbox Design | Machine Design- Interview Question and Answers

1. What purpose does the housing of gear-box serve?

Gear-box -housing or casing is used as container inside which, the gears, shafts, bearings and other components are “mounted.’ Also it prevents the entry of dust inside the housing and reduces noise of operation. That is, the housing Safe-guard the inner components.

2. What is the function of spacers in a gear-box? (Or) What spacers are as applied to a gear-box?

Spacers are sleeve like components, which are mounted, in shafts in-between gears and bearings or one gear and another gear in order to maintain the distance between them so as to avoid interruption between them .

3. Fill in the blanks of the following.

(a) The number of gears employed in a gear-box is kept to the minimum by arranging the speed of the spindle is ……………………… series.
(b) In a gear- box, for a set of gears, if the centre distance and module are same, then the sum of teeth of engaging pair will be …………..

a) Geometric series.
b) Equal.

4. What is a speed diagram? (or) what is ray diagram?

Speed diagram is the graphical representation of different speeds of output shaft, motor shaft and intermediate shafts.

5. For what purpose we are using gear-box?

Since the gear-box is provided with number of gears of different size arranged is different forms, we can get number of output speeds by operated motor at single speed.

6. Name the types of speed reducers.

a) Single reduction speed reduces.
b) Multi reduction speed reducers.

7. What does the ray-diagram of gear-box indicate?

The ray-diagram or kinematic arrangement of a gear box indicates arrangement of various gears in various shafts of the gear box in order to obtain the different output speeds from the single speed of the motor.

8. What is step ratio? Or define Progression ratio.

When the spindle speeds are arranged in geometric progression, then the ratio between the two adjacent speeds is known as step ratio or progression ratio.

9. What are the possible arrangements to achieve 12 speeds from a gear box?

(i) 3 x 2 x 2 scheme
(ii) 2 x 3 x 2 scheme
(iii) 2 x 2 x 3 scheme

10. What are the possible arrangements to achieve 16 speeds from a gear box?

(i) 4 x 2 x 2 scheme
(ii) 2 x 4 x 2 scheme
(iii) 2 x 2 x 4 scheme

11. Differentiate ray diagram and structural diagram.

• The ray diagram is a graphical representation of the structural formula.
• The structural diagram is a kinematic layout that shows the arrangement of gears in a gear box.

12. List any two methods used for changing speed in gear boxes.

• Sliding mesh gear box
• Constant mesh gear box and
• Synchromesh gear box.

13. What are preferred numbers?

Preferred numbers are the conveniently rounded off values derived from geometric series. There are five basic series, denoted as R5, R10, R20, R40, and R80 series.

14. Name the series in which speeds are arranged in multispeed gear boxes.

Basic series are R5, R10, R20 and R40.

15. Which type of gear is used in constant mesh gear box? Justify.

Helical gears are used in constant mesh gear boxes to provide quieter and smooth operation.

16. Where are multispeed gear boxes employed?

Multi speed gear boxes where employed wherever the variable spindle speeds are necessary.

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Sachin Thorat

Sachin is a B-TECH graduate in Mechanical Engineering from a reputed Engineering college. Currently, he is working in the sheet metal industry as a designer. Additionally, he has interested in Product Design, Animation, and Project design. He also likes to write articles related to the mechanical engineering field and tries to motivate other mechanical engineering students by his innovative project ideas, design, models and videos.

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