EPICYCLIC GEAR TRAINS INVOLVE ROTATION OF AT LEAST ONE GEAR AXIS AB...

4. Epicyclic gear trains involve rotation of at least one gear axis about some other

gear axis.

(a) 1, 2 and 3

(b) 1, 3 and 4 (c) 1, 2 and 4

(d) 2, 3 and 4

IES-26Ans. (c)

IES-27. Which one of the following is true for involute gears?

[IES-1995]

(a) Interference is inherently absent

(b) Variation in centre distance of shafts increases radial force

(c) A convex flank is always in contact with concave flank

(d) Pressure angle is constant throughout the teeth engagement.

IES-27Ans. (d) For involute gears, the pressure angle is constant throughout the teeth

engagement.

IES-28. In involute gears the pressure angle is

[IES-1993]

(a) Dependent on the size of teeth

(b) dependent on the size of gears

(c) Always constant

(d) always variable

IES-28Ans. (c) The pressure angle is always constant in involute gears.

Minimum Number of Teeth

IES-29. Which one of the following statements is correct?

[IES-2004]

Certain minimum number of teeth on the involute pinion is necessary in order to

(a) Provide an economical design

(b) avoid Interference

(c) Reduce noise in operation

(d) overcome fatigue failure of the teeth

IES-29Ans. (b)

IES-30. A certain minimum number of teeth is to be kept for a gear wheel

(a) So that the gear is of a good size

[IES-1999]

(b) For better durability

(c) To avoid interference and undercutting

(d) For better strength

IES-30Ans. (c)

o

IES-31. In

full

depth

1

degree involute system, the smallest number of teeth in

14

2

a pinion which meshes with rack with out interference is [IES-1992]

(a) 12

(b) 16

(c) 25

(d) 32

IES-32Ans. (d)

Design of Power Transmission System

S K Mondal’s

Chapter 3

IES-33. Match List I with List II and select the correct answer using the codes

given below the lists:

List I (Terminology)

List II (Relevant terms)

[IES-1995]

A. Interference

1. Arc of approach, arc of recess, circular pitch

B. Dynamic load on tooth

2. Lewis equation

C. Static load

3. Minimum number of teeth on pinion

D. Contract ratio

4. Inaccuracies in tooth profile

Codes:

A B C

D A B

C D

(a)

3

4

1

2

(b)

1

2

3

4

(c)

4

3

2

1

(d)

3

4

2

1

IES-33Ans. (d)

IES-34 Assertion

(A): When a pair of spur gears of the same material is in mesh, the

design is based on pinion.

[IES-2002; 1993]

Reason

(R): For a pair of gears of the same material in mesh, the 'strength factor'

of the pinion is less than that of the gear.

(a) Both A and R are individually true and R is the correct explanation of A

(b) Both A and R are individually true but R is not the correct explanation of A

(c) A is true but R is false

(d) A is false but R is true

IES-34Ans. (a)

Cycloidal teeth

IES-35. The curve traced by a point on the circumference of a circle which rolls

along the inside of affixed circle, is known as

[IES-1992]

(a)

Epicycloid

(b)

hypocycloid

(c)

Cardiod

(d)

involute

IES-35Ans. (b)

IES-36

In the mechanism shown above, link 3 has

[IES-2004]

(a) Curvilinear translation and all points in it trace out identical cycloids

(b) Curvilinear translation and all points in it trace out identical involutes

(c) Linear translation & all points in it trace out identical helices

(d) Linear translation & all points in it trace out identical ellipses

IES-36Ans. (a)

IES-37. A thin circular disc is rolling with a uniform linear speed, along a straight

path on a plane surface.

[IES-1994]

Consider the following statements in this regard: