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UNIT 5 TRANSMITTING ROTARY MOTION
FRICTION WHEELS
- In the following picture you have friction wheel system. Wheel A is the driver one, while wheel B is the driven one. If the driver one rotates clock-wise, in which direction will wheel C rotate? Put the wheels in decreasing speed order.
- We have a friction wheel system in which the 15 cm diameter driver wheel is rotating at 120 rpm and a driven one with 60 cm of diameter.
a) Draw the system indicating which is the driver and the driven wheel. b) Calculate the transmission ratio and the speed ratio. c) Calculate the speed of the driven wheel. d) If the driven wheel rotates clockwise, how will the driver one will do? e) Is it an increasing speed mechanism or a decreasing speed mechanism?
- In a friction wheel system the driver wheel has a diameter of 80 cm while the driven one has 20 cm.
a) Draw the system indicating which is the driver and the driven wheel. b) Calculate the speed of the driven wheel if the driver one rotates at 100 rpm. c) If the driver wheel rotates anti-clockwise, how will the driven one will do? d) Calculate transmission and speed ratio. e) When the driven wheel rotates 20 turns, how many turns are given by the driver one? f) Is it an increasing speed mechanism or a decreasing speed mechanism?
BELT DRIVES
- In the belt drive system of the figure, what will the speed be in the driven pulley if the driver one is running at 250 rpm?
- We have three pulleys with diameters 20, 40 and 60 mm. Use them to build a pulley train so the driven pulley speed is nine times the speed for the driver one. Draw the mechanism and explain the results using numbers.
- In the belt drive system of the figure, please indicate the direction of the motions in the different pulleys when the driver (A) rotates clock-wise.
- The engine of a washing machine is linked to 8 cm diameter pulley, while the container is linked to a 32 cm diameter pulley. If the highest speed for the engine is 1,500 rpm:
a) Which is the highest speed for the container? b) If we change the engine pulley for another one which is twice the size, how will this affect to the container speed?
- Indicate the direction of the motion for the following mechanisms.
- Indicate the direction of the motion for the following mechanisms when the first pulley on the left rotates clockwise.
GEARS
- Indicate the direction of the motion for the following gear mechanisms.
- A gear train is formed by three gears linked. The first one has 90 teeth, the second one 274 and the third one 180. If the first one rotates at 400 rpm, which will the speed be for the third one?
- We have an engine rotating at 3,000 rpm which is linked to a 20 teeth gear. This gear is linked to another gear with 60 teeth.
a) Draw the system indicating which is the driver and the driven gear. b) Calculate the transmission ratio and the speed ratio. c) Calculate the speed of the driven gear.
- You have a mechanism in which the driver gear has 14 teeth and rotates at 4,000 rpm, while the driven gear has 56 teeth.
a) Is it an increasing speed mechanism or a decreasing speed mechanism? b) Calculate the speed for the driven gear. c) If the driven gear rotates clockwise, how will the driver one will do? d) Calculate the number of turns given by the driven wheel in half an hour.
- In the following figure you can find the transmission system for a bicycle. When we pedal one turn, the pinion moves three turns.
a) Calculate the transmission ratio and the speed ratio. b) When we pedal at 50 rpm, calculate the speed of the wheel.
- In the following system the driver gear is rotating at 40 rpm while the driven one is doing it at 120 rpm.
a) Indicate which is the driven and the driver gears. b) Is it an increasing speed mechanism or a decreasing speed mechanism? c) Calculate the speed ratio and the transmission ratio. d) Calculate the speed of the driven gear if the driver one is rotating at 100 rpm.
- In the following system the speed is reduced in two steps. The two gears are exactly the same and the transmission ratio for the two of them is 1/3.
a) Calculate the speed ratio and the transmission ratio for the whole mechanism. b) If the driver gear (first one on the left) rotates at 45 rpm, calculate the speed for the driven one (last one on the right).
- In the gear train of the figure:
a) Indicate the direction of the motion of the driven gear when the driver one rotates clockwise. b) What is the function of the idler gear? c) When the speed of the driver gear is 100 rpm, calculate the speed for both the idler gear and the driven one. d) Calculate speed ratio and transmission ratio for the steps and the total system. e) When the driven gear rotates at 60 rpm, calculate the speed for the idler gear and the driver one. f) Is it an increasing speed mechanism or a decreasing speed mechanism?
- For the system in the figure, zA = 45, zB = zD = 15 and zC = 30:
a) Indicate the direction of the motion when gear A rotates clockwise. b) Calculate the speed for all the gears when gear A rotates at 40 rpm. c) Transmission ratio and speed ratio for all the steps and for the total system. d) Is it an increasing speed mechanism or a decreasing speed mechanism?
- For the gear train in the figure:
a) Indicate the direction of the motion of all the gears when the driver one rotates anti-clockwise. b) Calculate the speed of all the gears. c) Calculate speed ratio and transmission ratio for the steps and the total system. d) When the driven gear rotates at 60 rpm, calculate the speed for all the gears. e) Is it an increasing speed mechanism or a decreasing speed mechanism?
- In a gear system where the two gears have the same number of teeth, calculate:
a) Transmission ratio and speed ratio. b) Speed for the driven gear when the driver one rotates at 200 rpm. c) When the driven gear rotates clockwise, how will the driver one do?
- In the transmission system of the figure, calculate the speed for gear 5.
- A simple gear is shown in the figure. Driver gear A has 20 teeth. When shaft A has rotated 10 times, shaft B rotates 5 times.
a) How many teeth has gear B? b) What is the transmission ratio of the system? c) And the speed ratio? d) If shaft A rotates at 60 rpm, at what speed does shaft B rotate? e) If shaft A rotates anti-clockwise, in which direction does shaft B rotate?
MISCELLANEOUS
- In the transmission system of the figure:
a) What is the name of the system formed by elements 1 and 2? b) What is the name of the system formed by elements 3 and 4? c) If 1 rotates clockwise, draw arrows to indicate the rotation of the rest of elements d) If 3 rotates at 90 rpm and its diameter is 10 cm, what is the speed of 4 if its diameter is 2 cm? e) Calculate the transmission ratio between 3 and 4.
- Indicate the direction of the motion for the following mechanisms.
