Rolling Contact Bearings, Spur Gears and Helical Gears topics include: Bearings and its types, load carrying capacities, sliding contact bearings, viscosity, spur gears and its terminology, gear trains and helical gears. Here's what you should know about spur gears, helical gears, and rolling contact bearings: Spur gears: A cylindrical gear with teeth that are parallel to the shaft. Spur gears are the most popular type of cylindrical gear and are used to transfer mechanical motion. They are simple, efficient, and versatile, and are often used in applications where the rotational motion... Show more

Rolling Contact Bearings, Spur Gears and Helical Gears topics include: Bearings and its types, load carrying capacities, sliding contact bearings, viscosity, spur gears and its terminology, gear trains and helical gears.

Here's what you should know about spur gears, helical gears, and rolling contact bearings:
Spur gears: A cylindrical gear with teeth that are parallel to the shaft. Spur gears are the most popular type of cylindrical gear and are used to transfer mechanical motion. They are simple, efficient, and versatile, and are often used in applications where the rotational motion between two shafts needs to be parallel and coplanar.
Helical gears: A simple machine that controls the direction or strength of a force. Helical gears are used in applications that require high speeds, significant power transmission, or noise reduction. They are known for their smooth and efficient power transmission, making them a popular choice in industries such as automotive, manufacturing, and robotics.
Rolling contact bearings: When choosing bearings, consider the rated speed, dynamic axial or thrust load, and dynamic radial load. Helical gears require thrust or roller bearings, which are typically larger (and more expensive) than the simple bearings used with spur gears.

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Machine Design Practice Test: Rolling Contact Bearings, Spur Gears and Helical Gears

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25 Questions

1. Scoring is a ________ phenomenon.

FractureFatigueIn-outStick-slip

2. A single transverse weld is preferred over double transverse fillet weld.

FalseMaybeTrueDon't Know

3. Greater the velocity ratio, smaller the gearbox.

Greater the gearboxSize of gearbox remains unaffectedNone of the listedTrue

4. A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate the addendum.

5mm4.75mmNone of the listed5.25mm

5. Temperature rise in partial bearing is ____ than full bearing.

LesserGreaterUndeterminableEqual

6. Interference is maximum when the largest pinion is in mesh with the smallest gear.

Don't KnowMaybeTrueFalse

7. For a hydrostatic thrust bearing,
Thrust load=450kN, shaft speed=730rpm, shaft diameter=450mm, recess diameter=310mm, film thickness=0.15mm, viscosity of lubricant=160SUS and specific gravity=0.86.
Calculate supply pressure

4.01Mpa10.2Pa4.01Pa10.2Mpa

8. Which of the following is measure of stiffness?

ToughnessResilienceModulus of elasticityModulus of plasticity

9. There is problem of alignment in deep groove ball bearings.

Can’t be determinedIt aligns itself only in some particular casesNo, it is self-aligningYes

10. Which of the following are not true for petroff’s equation?

Bearing is subjected to light loadIs used to find coefficient of frictionFrictional torque is given by fpr²lShaft is considered concentric with the bearing

11. A pair of helical gears consist of 25 teeth pinion gear meshing with a 90 teeth gear. Calculate the ratio factor.

0.741.570.881.44

12. A rolling contact bearing is specified as X307. Determine the series.

Light seriesExtra light seriesMedium seriesHeavy series

13. Herringbone gear can be used in

None of theseBoth intersection and parallel shaftsIntersecting shafts onlyParallel shafts only

14. Stribeck equation gives dynamic load capacity of the bearing.

Don't KnowFalseMaybeTrue

15. A planetary gear train is shown in the figure. Number of teeth on the sun gear A, planet gear B and fixed ring gear D are given by 30, 70 and 140 respectively. Module is taken as 5mm. A pair of spur gears consist of 25 teeth pinion meshing with a 115 teeth gear. The module is 5mm. Calculate the gear ratio.

4.645.25

16. For a hydrostatic thrust bearing,
Thrust load=450kN, shaft speed=730rpm, shaft diameter=450mm, recess diameter=310mm, film thickness=0.15mm, viscosity of lubricant=160SUS and specific gravity=0.86.
Calculate flow requirement

0.89l/s38.94l/min28.8l/minNone of these

17. Newton law of viscosity states that shear stress is proportional to rate of shear at any point in the fluid.

Don't KnowTrueFalseMaybe

18. In hydrodynamic lubrication, film thickness remains unaffected by change in speeds.

Decrease with increase in speedIncrease with increase in speedTrueDisappear as the speed tends to infinty

19. The fundamental equation for viscous flow is given by ∆pbhᵌ/6µl where symbols have their usual meanings.

6 is to be replaced by 156 is to be replaced by 96 is to be replaced by 36 is to be replaced by 12

20. The bearing is subjected to a radial load of 4000N. Expected life for 90% bearings is 9000h and shaft is rotating at 1500rpm. Calculate the dynamic load capacity.

26.33kN42.21kN37.29kN35.22kN

21. The amount of backlash depends on

Centre distanceModuleAll of theseDiameteral pitch

22. In gear boxes and small size motors, rolling contact bearings are used.

MaybeTrueFalseDon't Know

23. Velocity ratio is the ratio angular velocity of driving gear to that of driven gear.

Don't KnowMaybeFalseTrue

24. Beam strength indicates the maximum value of radial force that a tooth can transmit without fatigue failure.

Don't KnowMaybeFalseTrue

25. As the module increases, index of size of gear decreases.

FalseDon't KnowTrueMaybe