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Unformatted text preview: that of Q, therefore
y1 – x1 × Wheel P y1 + x1 × TY TX
×
TQ TP Chapter 13 : Gear Trains
∴ y 1 = 0.2 x 1 – 300 Also
∴ l 471
...(iii) Speed of wheel Y = Speed of wheel Z or shaft I
x 1 + y 1 = x + y = – 1500
x 1 + 0.2 x 1 – 300 = – 1500 ...(iv)
...[From equation (iii)] 1.2 x 1= – 1500 + 300 = – 1200
or x 1 = – 1200/1.2 = – 1000 and y 1 = – 1500 – x 1 = – 1500 + 1000 = – 500 1. Speed and direction of the driven shaft O and the wheel P
Speed of the driven shaft O,
N O = y 1 = – 500 = 500 r.p.m. clockwise Ans.
and Speed of the wheel P, N P = y1 + x1 × TY TX
24
36
×
= – 500 – 1000 ×
×
120 144
TQ TP = – 550 = 550 r.p.m. clockwise Ans.
2. Torque tending to rotate the fixed wheel R
We know that the torque on shaft I or input torque T1 = 7500 × 60
P × 60
=
= 47.74 Nm
2π × N1 2π × 1500 and torque on shaft O or output torque, T2 = η × P × 60 0.8 × 7500 × 60
=
= 114.58 Nm
2π × NO
2π × 500 Since the input and output shafts rotate in the same direction (i.e. clockwise), therefore input
and output torques will be in opposite direction.
∴ Torque tending to rotate the fixed wheel R
= T2 – T 1 = 114.58 – 47.74 = 66.84 Nm Ans.
Example 13.24. An epicyclic bevel gear train (known as Humpage’s reduction gear) is shown
in Fig. 13.31. It consists of a fixed wheel C, the
driving shaft X and the driven shaft Y. The compound
wheel BD can revolve on a spindle F which can
turn freely about the axis X and Y.
Show that (i) if the ratio of tooth numbers
T B / T D is greater than TC / TE , the wheel E will rotate in the same direction as wheel A, and (ii) if the
ratio TB / T D is less than TC / T E, the direction of E is
reversed.
If the numbers of teeth on wheels A, B, C, D
and E are 34, 120, 150, 38 and 50 respectively and
7.5 kW is put into the shaft X at 500 r.p.m., what is
Fig. 13.31
the output torque of the shaft Y, and what are the
forces (tangential to the pitch cones) at the contact
points between wheels D and E and between whee...
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This note was uploaded on 02/13/2014 for the course MIE 301 taught by Professor Celghorn during the Fall '08 term at University of Toronto Toronto.
 Fall '08
 CELGHORN

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