Gears and Gear Trains · Theory of Machines · GATE ME

A cuboidal part has to be accurately positioned first, arresting six degrees of freedom and then clamped in a fixture, to be used for machining. Locating pins in the form of cylinders with hemi-spherical tips are to be placed on the fixture for positioning. Four different configurations of locating pins are proposed as shown. Which one of the options given is correct?

Two meshing spur gears 1 and 2 with diametral pitch of 8 teeth per mm and an angular velocity ratio |ω2 |/|ω1 | = 1/4, have their centers 30 mm apart. The number of teeth on the driver (gear 1) is _______ .

(Answer in integer)

A gear train is made up of five spur gears as shown in the figure. Gear $$2$$ is driver and gear $$6$$ is driven member. $${N_{2,}}{N_{3,}}{N_{4,}}{N_5}$$ and $${N_6}$$ represent number of teeth on gears $$2,3,4,5,$$ and $$6$$ respectively, The gear(s) which act(s) as idler(s) is/are

Which one of the following is used to convert a rotational motion into a translational motion?

The following are the data for two crossed helical gears used for speed reduction:
Gear $$I:$$ Pitch circle diameter in the plane of rotation 80mm and helix angle 30^o

Gear $$II:$$ Pitch circle diameter in the plane of rotation 120mm and helix angle 22.5^o

If the input speed is 1440 rpm. The output speed in rpm is

Tooth interference in an external involute spur gear pair can be reduced by

A 1.5 kW motor is running at 1440 rev/min. Its is to be connected to a stirrer running at 36 rev/min. The gearing arrangement suitable for this application is

In spur gears having involute teeth, the product of circular pitch and diametral pitch is _________

The Levi type-A train illustrated in the figure has gears with module $m = 8 \text{ mm/tooth}$. Gears 2 and 3 have 19 and 24 teeth respectively. Gear 2 is fixed and internal gear 4 rotates at 20 rev/min counter-clockwise. The magnitude of angular velocity of the arm is _________ rev/min. (rounded off to 2 decimal places)

A schematic of an epicyclic gear train is shown in the figure. The sun (gear 1) and planet (gear 2) are external, and the ring gear (gear 3) is internal. Gear 1, gear 3 and arm OP are pivoted to the ground at O. Gear 2 is carried on the arm OP via the pivot joint at P, and is in mesh with the other two gears. Gear 2 has 20 teeth and gear 3 has 80 teeth. If gear 1 is kept fixed at 0 rpm and gear 3 rotates at 900 rpm counter clockwise (ccw), the magnitude of angular velocity of arm OP is __________rpm (in integer).

In an epicyclic gear train, shown in the figure, the outer ring gear is fixed, while the sun gear rotates counterclockwise at 100 rpm. Let the number of teeth on the sun, planet and outer gears to be 50, 25 and 100, respectively. The ratio of magnitudes of angular velocity of the planet gear to the angular velocity of the carrier arm is _________.

A gear train shown in the figure consists of gears P, Q, R and S. Gear Q and gear R are mounted on the same shaft. All the gears are mounted on parallel shafts and the number of teeth of P, Q, R and S are 24, 45, 30 and 80, respectively. Gear P is rotating at 400 rpm. The speed (in rpm) of the gear S is _________ .

In the gear train shown, gear 3 is carried on arm 5. Gear 3 meshes with gear 2 and gear 4. The number of teeth on gear 2, 3, and 4 are 60, 20, and 100, respectively. If gear 2 is fixed and gear rotates with an angular velocity of 100 rpm in the counterclockwise direction, the angular speed of arm 5 (in rpm) is

A pinion with radius $${r_1}$$, and inertia $${{\rm I}_1}$$ is driving a gear with radius $${r_2}$$ and inertia $${{\rm I}_2}$$ . Torque $${\tau _1}$$ is applied on pinion. The following are free body diagrams of pinion and gear showing important forces ($${F_1}$$and $${F_2}$$) of interaction. Which of the following relations hold true?

Gear 2 rotates at 1200 rpm in counter clockwise direction and engages with Gear 3. Gear 3 and Gear 4 are mounted on the same shaft. Gear 5 engages with Gear 4. The numbers of teeth on Gears 2, 3, 4 and 5 are 20, 40, 15 and 30, respectively. The angular speed of Gear 5 is

It is desired to avoid interference in a pair of spur gears having a 20^o pressure angle. With increase in pinion to gear speed ratio, the minimum number of teeth on the pinion

A compound gear train with gears P, Q, R and S has number of teeth 20, 40, 15 and 20, respectively. Gears Q and R are mounted on the same shaft as shown in the figure below. The diameter of the gear Q is twice that of the gear R. If the module of the gear R is 2 mm, the center distance in mm between gears P and S is

For the epicyclic gear arrangement shown in the figure, $${{\omega _2} = 100}$$ rad/s clockwise (CW) and $${{\omega _{arm}} = 80}$$ rad/s counter clockwise (CCW). The angular velocity $${{\omega _5}}$$ (in rad/s) is

An epicyclic gear train is shown schematically in the adjacent figure The sun gear 2 on the input shaft is a 20 teeth external gear. The planet gear 3 is a 40 teeth external gear. The ring gear 5 is a 100 teeth internal gear. The ring gear 5 is fixed and the gear 2 is rotating at 60 rpm CCW (CCW $$=$$ counter-clockwise and CW $$=$$ clockwise)

The arm 4 attached to the output shaft will rotate at

A planetary gear train has four gears and one carrier. Angular velocities of the gears are $${\omega _1},{\omega _2},{\omega _3},$$ and $${\omega _4}$$ respectively. The carrier rotates with angular velocity $${\omega _5}.$$

For $${{\omega _1} = 60}$$ rpm clockwise $$(CW)$$ when looked from the left, what is the angular velocity of the carrier and its direction so that Gear $$4$$ rotates in counter clockwise $$(CCW)$$ direction at twice the angular velocity of Gear $$1$$ when looked from the left?

A planetary gear train has four gears and one carrier. Angular velocities of the gears are $${\omega _1},{\omega _2},{\omega _3},$$ and $${\omega _4}$$ respectively. The carrier rotates with angular velocity $${\omega _5}.$$

What is the relation between the angular velocities of Gear $$1$$ and Gear $$4$$?

Match the items in columns $$I$$ and $$II$$

Column $$I$$
$$P.$$ Addendum
$$Q.$$ Instantaneous center of velocity
$$R.$$ Section modulus
$$S.$$ Prince circle

Column $$II$$
$$1.$$ Cam
$$2.$$ Beam
$$3.$$ Linkage
$$4.$$ Gear

The overall gear ratio in a 2 stage speed reduction gear box (with all spur gears) is 12. The input and output shafts of the gear box are collinear. The countershafts which is parallel to the input and output shafts has a gear (Z₂ teeth) and pinion (Z₃ = 15 teeth) to mesh with pinion (Z₁ = 16 teeth) on the input shafts and gear (Z₄ teeth) on the output shafts respectively. It was decided to use a gear ratio of 4 with 3 module in the first stage and 4 module in the second stage.

The centre distance in the second stage is

The overall gear ratio in a 2 stage speed reduction gear box (with all spur gears) is 12. The input and output shafts of the gear box are collinear. The countershafts which is parallel to the input and output shafts has a gear (Z₂ teeth) and pinion (Z₃ = 15 teeth) to mesh with pinion (Z₁ = 16 teeth) on the input shafts and gear (Z₄ teeth) on the output shafts respectively. It was decided to use a gear ratio of 4 with 3 module in the first stage and 4 module in the second stage.

Z₂ and Z₄ are

The sun gear in the figure is driven clockwise at 100 rpm. The ring gear is held stationary. For the number of teeth shown on the gears, the arm rotations at

List $$I$$ (Gear types)
(a) Worm gears
(b) Cross helical gears
(c) Bevel gears
(d) Spur gears

List $$II$$ (Applications)
1. Parallel shafts
2. Non-parallel, intersecting shafts
3. Non-parallel, non intersecting shafts
4. Large speed ratios

The arm OA of an epicylic gear train shown in Fig. revolves counter clockwise about O with an angular velocity of 4 rad/sec. Both gears are of same size. The angular velocity of gear C, if the sun gear B is fixed, is

A planetary gear train is shown in Figure. Internal gear (1) has 104 teeth and is held fixed and planet gear (2) has 96 teeth. How much does the planet gear rotate for sixty revolutions of the planet carrier (3) in clockwise direction?

Below Fig show a planetary gear train. Gears 2, 4 and 5 have 24, 40 and 144 teeth respectively. Gear 5 is fixed. Gear 2 is rotating clockwise at 700 rpm. What will be the rpm of the arm and gear 4?