Machine Design

Group 2 12.

In a flange coupling, the weakest element should be: a. Flange b. Shaft c. Key d. Bolts

13.

A flange coupling is: a. used for non collinear shaft b. a flexible coupling c. used for collinear shaft d. used only on small shaft rotating at low speed

14.

A flange coupling is to connect two 57mm diameter shafts. The hubs of the couplings are each 111mm in diameter, 92mm thick and the flange webs are 19mm thick. Six 16mm diameter bolts in a 165 mm diameter bolt circle connect the flanges. The keyway is 6mm shorter than the hub's thickness and the key is 14mm x 14mm. The coupling is to transmit 45 kW at 160 rpm. For all parts, the yield point value in shear is one-half the yield point value in tension and compression which is 448 MPa. Find the following stresses and factors of safety based on yield point:

Sys = (0.5)(448) = 224MPa a. Shear in the key

b. bearing in the key

c. shear in bolts

d. bearing in the bolts

e. shear in shaft

f. shear in hub

15.

For a single universal joint, the shaft angle should be_____ degrees maximum and much less if used on high rotational speed. a. 12 b. 16 c. 15 d. 14

16.

Compute how many 3/8" diameter set screws are required to transmit 3hp at a shaft speed of 1000rpm. the shaft diameter is 1 inch. a. 2 b. 3 c. 4 d. 5

(2 screws)

17.

A lever, secured to a 50mm round shaft by a steel tapered pin (d=10mm), has a pull of 200 Newtons at a radius of 800mm. Find S, the working stress on the pin, in MPa. Consider double shear on the pin. a. 41 b. 43 c. 46 d. 48

18.

The torsional capacity of a spline fitting is based on the maximum allowable pressure on active surfaces that is 6.89Mpa. The spline’s major and minor diameters are 76.20mm and 60.96mm respectively. The total number of splines is 6. Determine the length of spline needed for a transmitted torque of 745.85N-m. a. 69.10 mm b. 65.25 mm c. 68.95 mm d. 67.75 mm GIVEN: S= 6.89 MPa or N/ D= 76.20mm d= 60.96mm N= 6 T= 745.85 N.m= 745850 N.mm L=? SOLUTION:

L = 69.05mm or 69.10mm

19.

From the above problem, determine the total force required to slide the spline axially if the coefficient of friction is 0.10. Assume that the torque is equally distributed among the splines. a. 2,175.13 N b. 2,751.25 N c. 2,178.35 N d. 2,200.18 N SOLUTION:

T=F x r x N

F = 362.521 N = (362.521 N) (6 spline) = 2175.126 N

2175.13 N

20.

Two short shafts with identical diameters of 38.10mm are connected by a coupling, whose flanges are fitted with 4 bolts on a 100mm bolt circle. The shafts runs at a speed of 400rpm. If the allowable compressive stress on the flanges is 15Mpa, determine the maximum power that can be transmitted by the short shaft. a. 27.12 kW b. 24.75 kW c. 25.85 kW d. 26.50 kW Given: D = 38.10 mm Nb = 4 bolts

Formula:

Doc = 100 mm Ss = 12 N/mm2 Sc = 15 N/mm2 Pmax = ? Solution:

21.

From the above problem, determine the diameter of the bolts to be used. a. 18.32 mm b. 16.50 mm c. 20.25 mm d. 22.75 mm Solution:

22.

From the same problem above, determine the minimum flange web thickness required. a. 11.50 mm b. 10.75 mm c. 12.75 mm d. 14.75 mm Solution:

MACHINE DESIGN II GROUP 2 MEMBERS 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24.

PASAHOL, JINKY EVANGELISTA, KHAY ESTRADA, QUENIE MARIN, EXLY JANE BAUDIN, RONA REYES, CAMELA JOYCE ROZOL, REINALYN MORALES, NEILBARTH LIRIOS, WILSON CASTILLO, KENSY JO RELOX, JAYSON CALVIN SORIANO, ROMMEL TANCIOCO, RAFAEL ALVARADO, MARC REDD FERRANCO, MARC MICHAEL FRANCISCO, KEVIN CANTUBA, JOHN PAUL SANTOS, JESSTER CABRA, DIANE MOJICA, DENIEL NOVILLA, RENZ DEQUITO, SHAEL MARASIGAN, ANTHONY QUISING, KARL