Frictional Drive in Textile Part 1:Drum drive, belt drive and chain drive

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Frictional Drive in Textile Part 1Drum drive,
belt drive and chain drive
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Frictional Drive

1. What is frictional drives
2. Types of frictional drives
3. Drum drive (eg cheese winding)
4. Belt drive (spinning, weaving)
5. Vee-belt drive (motor power )
6. Chain-and-sprocket drive

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1) Frictional Drives

• Many drives for textile machines rely on the
  friction between the driving element and the
  driven element. Examples
• Belt and rope drives
• Drum drives to cone in yarn preparation
• Drum drives to warping beams
• The common feature is one element has a hard
  surface and the other is a relatively soft surface

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Drum Drive
Driven
Driver
Cone winding is a typical example of frictional
drive
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Drum drive

• Figure 1 shows the cheese sits on top of the drum
  (driven).
• The surface speed of drum (driver) is Vn1 x pi x
  d1
• Assume no slippage between the drum and cheese,
  the surface speed will be
• n1 x pi x d1 n2 x pi x d2
• n1 /n2 d2 /d1

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Drum drive

• The last equation shows that the ratio of the
  rotational speeds of the two elements is the
  inverse ratio of their diameter.
• It should be noted that the running speed
  (rev/min) for the empty cheese (smaller diameter)
  is higher than full cheese (bigger diameter).

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ExampleCalculation for cheese winding
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Question 1

• A drum has 12cm diameter and rotates at 2650
  rev/min., find out
• A) the actual winding rate (m/min)
• B) the rev/min of the cheese at start (empty
  package)
• C) the rev/min of the cheese at 18cm diameter
  (full package)

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Answer 1

• 1) Actual winding rate
• V n1 x pi x d1
• V (2650 x 3.14 x 12)/100 1000 m/min
• 2) Rev/min at start
• n1 x d1 x pi n2 x d2 x pi
• 2650 x 12 n2 x 5 n26360 rev/min
• 3) Rev/min at 18 cm
• 2650 x 12 n2 x 18 n21767 rev/min
• It should note that the rev/min for empty package
  is running faster than full package

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2) Belt driveFlat belt drive
Driven
Driver
Figure 2
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Flat belt drive

• If the belt has no thickness, the surface speed
• n1 x d1 x pi n2 x d2 x pi
• If the thickness is t, the surface speed
• n1 x (d1 t) n2 x (d2 t)

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Question 2

• In Fig. 2, pulley A rotates at 120 rev/min and
  has diameter of 30 cm. Pulley B has a diameter of
  50 cm. If the belt is 0.6 cm thick, estimate the
  number of rev/min of pulley B, with slippage
  ignored.
• Suppose 4 slippage occurred, what is the rev/min
  of pulley B?

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Answer 2

• n1 x (d1 t) n2 x (d2 t)
• 120 x (300.6) n2 x (500.6)
• n272.6 rev/min
• If 4 slippage, the pulley B will be
• 72.6 x 0.96 69.7 rev/min

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Vee-belt drive

• The flat belt drive as discussed has the
  limitation to the power that it can transmit.
• Owning to the wedging effect, the Vee-belt
  drive can trasmit four times as much power as the
  flat belt for the same cross-sectional area.
• Vee-belt drive is a common transmitting power on
  textile machine, e.g from the electric motor to
  the main shaft of the machine.

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Vee-belt drive
High transmitting power of Vee-belt drive
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Question 3Vee-belt

• The linear velocity of a vee-belt is 1200 m/min.
  If the pitch diameters of the motor pulley and
  machine pulleys are 16 and 36 cm, calculate the
  motor speed and the machine speed

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Answer 3

• Surface speed V n1 x pi x d1
• Linear speed speed of pulley (rev/min) x pi x
  d1
• 1200 m/min (n1 x 3.14 x 16)/100 n12385
  rev/min. (motor speed)
• 1200 m/min (n2 x 3.14 x 36)/100 n21060
  rev/min (machine speed)

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Chain and sprocket drive

• This is a positive drive with a driving sprocket
  connected to the driven sprocket by a roller
  chain.
• The driving chain from bicycle is an example of
  chain-and-sprocket drive.
• It is simple and versatile.

(Rev/min of driving / rev/min of driven) (no.
of teeth of driven / no of teeth of driver)
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Chain-and-Sprocket drive
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Question 4

• A sprocket of 24 teeth rotates at 56 rev/min and,
  by roller-chain drives, causes a sprocket of 40
  teeth to rotate. Calculate the number of rev/min
  of the driven sprocket.

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Answer 4

• 56 x (24/40) 33.6 rev/min.
• One advantage of a chain drive is that several
  sprockets may be driven from one driving
  sprocket.
• One of these guide sprockets may be adjustable so
  that any stretch in the chain may be taken up.