Pm clockwise ans and speed of the wheel p n p y1 x1

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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 N-m 2π × N1 2π × 1500 and torque on shaft O or output torque, T2 = η × P × 60 0.8 × 7500 × 60 = = 114.58 N-m 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 N-m 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 B-D 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.

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