The form factor of a helical gear __________ with the increase in the helix angle.

If T is the actual number of teeth on a helical gear and $$\varphi $$ is the helix angle for the teeth, then formative number of teeth is written as

A

$${\text{T}}{\sec ^3}\varphi $$

B

$${\text{T}}{\sec ^2}\varphi $$

C

$$\frac{{\text{T}}}{{{{\sec }^3}\varphi }}$$

D

$${\text{Tcosec}}\varphi $$

In helical gears, the right hand helixes on one gear will mesh __________ helixes on the other gear.

A

Right hand

B

Left hand

C

Both A and B

D

None of these

While cutting helical gears on a non-differential gear hobber, the feed change gear ratio is

A

Independent of index change gear ratio

B

Dependent on speed change gear ratio

C

Interrelated to index change gear ratio

D

Independent of speed and index change gear ratio

The helix angle for single helical gears ranges from

A

10° to 15°

B

15° to 20°

C

20° to 35°

D

35° to 50°

The helix angle for double helical gears may be made up to

A

45°

B

60°

C

75°

D

90°

In which of the following type of gear train the first gear and the last gear are co-axial.

A

Simple gear train

B

Compound gear train

C

Reverted gear train

D

None of the mentioned

In helical gears, the distance between similar faces of adjacent teeth along a helix on the pitch cylinders normal to the teeth, is called

A

normal pitch

B

axial pitch

C

diametral pitch

D

module

A close coil helical spring when subjected to a moment M having its axis along the axis of the helix

A

It is subjected to pure bending

B

Its mean diameter will decrease

C

Its number of coils will increase

D

All the above

In order to ensure self locking in a screw jack, it is essential that helix angle is __________ friction angle.

A

Larger than

B

Smaller than

C

Equal to

D

None of these

In a screw jack, the effort required to lift the load W is given by (where $$\alpha $$ = Helix angle and $$\varphi $$ = Angle of friction)

A

$${\text{P}} = {\text{W}}\tan \left( {\alpha - \varphi } \right)$$

B

$${\text{P}} = {\text{W}}\tan \left( {\alpha + \varphi } \right)$$

C

$${\text{P}} = {\text{W}}\tan \left( {\varphi - \alpha } \right)$$

D

$${\text{P}} = {\text{W}}\cos \left( {\alpha + \varphi } \right)$$

The form factor of a helical gear __________ with the increase in the helix angle.

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