Or td 4 tb we know that t d dd m 224 4 56 ans t

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: s. Note : This picture is given as additional information and is not a direct example of the current chapter. or TD = 4 TB We know that T D = dD / m = 224 / 4 = 56 Ans. ∴ T B = T D / 4 = 56 / 4 = 14 Ans. ...(i) ...[From equation (i)] Let dB, dC and dD be the pitch circle diameters of sun wheel B , planet wheels C and internally toothed ring D respectively. Assuming the pitch of all the gears to be same, therefore from the geometry of Fig. 13.13, dB + 2 dC = dD Since the number of teeth are proportional to their pitch circle diameters, therefore TB + 2 TC = TD ∴ or 14 + 2 T C = 56 T C = 21 Ans. Example 13.10. Two shafts A and B are co-axial. A gear C (50 teeth) is rigidly mounted on shaft A. A compound gear D-E gears with C and an internal gear G. D has 20 teeth and gears with C and E has 35 teeth and gears with an internal gear G. The gear G is fixed and is concentric with the shaft axis. The compound gear D-E is mounted on a pin which projects from an arm keyed to the shaft B. Sketch the arrangement and find the number of teeth on internal gear G assuming that all gears have the same module. If the shaft A rotates at 110 r.p.m., find the speed of shaft B. Solution. Given : T C = 50 ; T D = 20 ; T E = 35 ; N A = 110 r.p.m. The arrangement is shown in Fig. 13.14. Number of teeth on internal gear G Let dC , dD , dE and dG be the pitch circle diameters of gears C, D, E and G respectively. From the geometry of the figure, dG d d d = C+ D+ E 2 2 2 2 or dG = dC + dD + dE l Chapter 13 : Gear Trains 449 Let T C , T D , T E and T G be the number of teeth on gears C, D, E and G respectively. Since all the gears have the same module, therefore number of teeth are proportional to their pitch circle diameters. ∴ T G = T C + T D + T E = 50 + 20 + 35 = 105 Ans. Fig. 13.14 Speed of shaft B The table of motions is given below : Table 13.9. Table of motions. Revolutions of elements Step No. Conditions of motion Arm Gear C (or shaft A) Compound gear D-E TC TD 1. Arm fixed - gear C rotates through + 1 r...
View Full Document

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.

Ask a homework question - tutors are online