Shafts, Keys and Couplings in Machine Design topics include: Transmission shafts, shaft design and keys, couplings and pin flexible coupling. In machine design, shafts, keys, and couplings are mechanical components that connect, transfer power, and absorb misalignments.  Keys: These pieces of metal are inserted into slots in the shaft and hub of a rotating machine part. Keys prevent relative rotation between the shaft and rotating elements, such as gears, flywheels, sprockets, and pulleys. Keys are made from ductile materials like mild steel and plain carbon steel. In corrosive... Show more

Shafts, Keys and Couplings in Machine Design topics include: Transmission shafts, shaft design and keys, couplings and pin flexible coupling.

In machine design, shafts, keys, and couplings are mechanical components that connect, transfer power, and absorb misalignments. 

Keys: These pieces of metal are inserted into slots in the shaft and hub of a rotating machine part. Keys prevent relative rotation between the shaft and rotating elements, such as gears, flywheels, sprockets, and pulleys. Keys are made from ductile materials like mild steel and plain carbon steel. In corrosive environments, brass and stainless steel are used. 
Couplings: These devices join two shafts together and allow for some misalignment or flexibility between them. Shaft couplings connect the drive shaft and driven shaft of a motor to transmit power. They introduce mechanical flexibility, providing tolerance for shaft misalignment. 

There are two types of shaft couplings:
Rigid shaft couplings: Designed for shafts with minimal misalignments. They are used when precision alignment is necessary.
Flexible couplings: Have flexible elements that allow for misalignments and axial displacement. They are more advantageous than rigid shaft couplings, which require manual alignment. 

Show less

Machine Design Practice Test: Shafts, Keys and Couplings in Machine Design

Time left 00:00

25 Questions

1. The layout of a shaft supported on bearings at A & B is shown. Power is supplied by means of a vertical belt on pulley B which is then transmitted to pulley C carrying a horizontal belt. The angle of wrap is 180’ and coefficient of friction is 0.3. Maximum permissible tension in the rope is 3kN. The radius of pulley at B & C is 300mm and 150mm. Calculate the tension in the rope of pulley C.

5468.4N ad 8678.3N6778.3N and 7765.3N5948.15N and 2288.75NNone of the listed

2. A muff coupling is connecting two shafts. The torque involved is 650N-m. The shaft diameter is 45mm with length and height of the key being 14mm and 80mm respectively. Find the compressive stress induced in the key.

70.1 N/mm²None of the listed51.6N/mm²45.5N/mm²

3. If 8 bolts are emplaced in a clamp coupling with shaft diameter 80mm d, calculate the tensile force on each bolt if coefficient of friction is 0.3 and torque transmitted is 4000N-m.

45968.3N51234.4N41666.7NNone of the listed

4. Calculate the force acting on the each pin in flexible coupling if torque transmitted is 397N-m and PCD=120mm with number of pins 6.

None of the listed1320.3N1400.3N1102.8N

5. Does shaft has to be shifted i axial direction to remove clamp coupling.

YesDon't KnowMaybeNo

6. Hollow saddle key is superior to flat saddle key as far as power transmitting capability is concerned.

Don't KnowMaybeTrueFalse

7. The layout of a shaft supported on bearings at A & B is shown. Power is supplied by means of a vertical belt on pulley B which is then transmitted to pulley C carrying a horizontal belt. The angle of wrap is 180’ and coefficient of friction is 0.3. Maximum permissible tension in the rope is 3kN. The radius of pulley at B & C is 300mm and 150mm. If allowable shear stress in the shaft is 70N/mm² and torsional and bending moments are M=1185000N-mm and m=330000N-mm, find the diameter of the shaft.

40.3mm36.8mm39.7mm44.7mm

8. Is it necessary for an axle to be ______ with respect to rotating element?

MovingNone of the listedStationaryMoving or stationary

9. The layout of a shaft supported on bearings at A & B is shown. Power is supplied by means of a vertical belt on pulley B which is then transmitted to pulley C carrying a horizontal belt. The angle of wrap is 180’ and coefficient of friction is 0.3. Maximum permissible tension in the rope is 3kN. The radius of pulley at B & C is 300mm and 150mm. Calculate the torque supplied to the shaft.

657.3N-mNone of the listed453.5N-m549.3N-m

10. Flexible shafts have _______ rigidity in torsion making them flexible.

LowVery highInfinitely smallHigh

11. When the shaft is subjected to pure bending moment, the bending stress is given by?

None of the listed8M/πdᵌ32M/πdᵌ16M/πdᵌ

12. If shaft diameter is 30mm and number of pins emplaced are 6, then the diameter of the pin will be?

5.6mm5.9mm6.1mm6.4mm

13. If 8 bolts are emplaced in a clamp coupling with shaft diameter 80mm d, calculate the diameter of each bolt if coefficient of friction is 0.3 and torque transmitted is 4000N-m. Permissible tensile stress is 80N/mm².

25mm21mm27mm23mm

14. Determine the length of kennedy key required to transmit 1200N-m and allowable shear in the key is 40N/mm². The diameter of shaft and width of key can be taken as 40mm and 10mm respectively.

46mm53mm36mm49mm

15. While designing shaft on the basis of torsional rigidity, angle of twist is given by?

Ml/Gd⁴None of these292 Ml/Gd⁴584Ml/Gd⁴

16. The shaft is always stepped with ________ diameter at the middle portion and __________ diameter at the shaft ends.

Zero, infinityMinimum, maximumMaximum, minimumMinimum, minimum

17. If shaft diameter is 40mm, calculate the diameter of sleeves in clamp coupling.

60mm40mm80mm100mm

18. Involute splines have stub teeth with a pressure angle of ___

Can’t be determined453060

19. Determine the diameter of the bolts used in rigid flange coupling if transmitted torque is 270N-m, pitch circle diameter=125mm and four bolts are emplace in the coupling. Permissible shear stress in the bolts is 70N/mm².

3.8mm3.6mm4mm4.4mm

20. Find the shear stress in a flange at the junction of hub in rigid flanged coupling if torsional moment is 2980N-m and diameter of hub being 125mm. Also the thickness of flange is 25mm.

4.22N/mm²6.77N/mm²10.24N/mm²4.84N/mm²

21. The hub is treated as a solid shaft while calculating torsional shear stress in the hub.

Don't KnowMaybeTrueFalse

22. A coupling is a mechanical device that temporarily joins two rotating shafts to each other.

TrueMaybeFalseDon't Know

23. Solid shafts are used in epicyclic gearboxes.

Don't KnowTrueFalseMaybe

24. Splines are keys.

FalseDon't KnowMaybeTrue

25. The layout of a shaft supported on bearings at A & B is shown. Power is supplied by means of a vertical belt on pulley B which is then transmitted to pulley C carrying a horizontal belt. The angle of wrap is 180’ and coefficient of friction is 0.3. Maximum permissible tension in the rope is 3kN. The radius of pulley at B & C is 300mm and 150mm. If bending moment on point B in horizontal plate is M and in vertical plane is m, then the net bending moment at point B is?

M+mMm√M²+m²