Reference no: EM132986199

MET23BO Mechanical Technology

QUESTION 1: MAINTENANCE

1.1. Calculate the belt length for an open drive if the pulley diameter is 450 mm and 1 250 mm, respectively. The centre distance is 2 400 mm. (6)

1.2. A flat belt is used to transmit 25 kW at 250 r/min. The driving pulley diameter is 150 mm and the belt contact angle is 175º. The coefficient of friction is 0,35. The two shafts are 1,8 m from each other. Calculate:

1.2.1. The ratio of the belt tensions. (3)
1.2.2. The belt speed in metres per second. (3)
1.2.3. The tension T1 and T2. (6)

1.3. FIGURE 1.1 below shows a belt drive system. The pulley, with a diameter of 0,24 m, drives the driven pulley with a diameter of 0,36 m. The driven pulley rotates at 733,33 r/min. T1 = 360 N and T2 = 90 N.

Calculate the:

1.3.1 Rotation frequency of the driver pulley in r/min. (3)
1.3.2 Power transmitted. (2)
1.3.3 Belt speed of the system in m.s-1. (2)

QUESTION 2

2.1 Two parallel shafts are to be connected by spur gears with a centre distance of exactly 140 mm. The gears have a velocity ratio of 3 to 2 and a module of 5. Calculate:
2.1.1 The number of teeth in each gear (13)
2.1.2 The outside diameter of the pinion (2)
2.1.3 The outside diameter of the gear wheel (2)
2.1.4 The circular pitch of the teeth (2)
2.1.5 The tooth height (2)

2.2 FIGURE 2.1 shows two spur gears that mesh.

Use the information above and calculate the:

2.2.1 Module of the small gear. (2)
2.2.2 Outside diameter of the large gear. (2)
2.2.3 PCD of the large gear. (2)
2.2.4 Dedendum of the large gear. (2)

2.3 FIGURE 2.2 shows a gear drive for a machine. The motor delivers 5 ???? and no losses occur. The electric motor turns at 850 ??/??????. Calculate the torque available at the machine spindle.