Which one of the following is true for involute gears?

Consider the following statements: 1. In spur gears, the contact occurs abruptly on a line parallel to the axis, and the disengagement too is abrupt. 2. In helical gears, both loading and unloading are gradual, and therefore, these happen more smoothly and less noisily 3. When two gears mesh, any arbitrary shape of the tooth can be chosen for the profile of the teeth of any one of the two gears, and the profile for the other shall be obtained by applying the law of gearing. Which of the above statements are correct?

A

1 and 2 only

B

1 and 3 only

C

2 and 3 only

D

1, 2 and 3

Which of the following statements are correct for mating gears with involute profiles? 1. The pressure angle, from the start of the engagement to the end of the engagement, remains constant. 2. The pressure angle is maximum at the beginning of the engagement, reduces to zero at pitch point, starts decreasing and again becomes maximum at the end of the engagement. 3. The face and flank of the teeth are generated by a single curve and the normal to this curve at any point is tangent to the base circle of the gear. 4. The centre distance for a pair of mating gears can be varied within limits without altering the velocity ratio. Select the correct answer using the code given below.

A

1, 3 and 4

B

1 and 3 only

C

2 and 4 only

D

2, 3 and 4

Which of the following statements are correct for mating gears with involute profiles? (i) The pressure angle, from the start of the engagement to the end of the engagement, remains constant. (ii) The pressure angle is maximum at the beginning of the engagement, reduces to zero at pitch point, starts decreasing and again becomes maximum at the end of the engagement. (iii) The face and flank of the teeth are generated by a single curve and the normal to this curve at any point is tangent to the base circle of the gear. (iv) The centre distance for a pair of mating gears can be varied within limits without altering the velocity ratio. Select the correct answer using the code given below.

A

1, 3 and 4

B

1 and 3 only

C

2 and 4 only

D

2,3 and 4

Involute gears have greater contact area as compared to cycloidal gears.

A

True

B

False

Gears having teeth cut on the rotating face plane of the gear and mate with standard involute spur gears are known as

A

mitre gear

B

face gear

C

spur gears on helical gears

D

none of the mentioned

Consider the following statements: In case of helical gears, teeth are cut at an angle to the axis of rotation of the gears. 1) Helix angle introduces another ratio called axial contact ratio. 2) Transverse contact ratio is equal to axial contact ratio in helical gears. 3) Large transverse contact ratio does not allow multiple teeth to share the load. 4) Large axial contact ratio will cause larger axial force component Which of the above statements are correct?

A

1 and 2

B

2 and 3

C

1 and 4

D

3 and 4

Among the following types of gears, which gears offer a refinement over spur gears?

A

Skew Gear

B

Advanced spur gears

C

External Gears

D

Helical Gears

Statement (I): Two non-intersecting and non-parallel, i.e., non-coplanar, shafts connected by gears are called skew-bevel gears or spiral gears, and this type of gearing has a line contact the rotation of which about the axes generates the two hyperboloid pitch surfaces. Statement (II): A hyperboloid is a 3D surface formed by revolving a straight line about an axis (not in the same plane), such that every point on the line remains at a constant distance from the axis.

A

Both Statement I) and Statement II) are individually true and Statement II) is the correct explanation of Statement I)

B

Both Statement I) and Statement II) are individually true but Statement II) is not the correct explanation of Statement I)

C

Statement I) is true but Statement II) is false

D

Statement I) is false but Statement II) is true

Two 25° involute spur gears have a module of 7 mm. The addendum is equal to one module. If the larger gear has 60 teeth and the pinion has 30 teeth, they will interfere with each other. True or false?

A

True

B

False

In a gear having involute teeth, the normal to the involute is a tangent to the

A

pitch circle

B

base circle

C

addendum circle

D

dedendum circle

Which one of the following is true for involute gears?

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