Design of gear box easy approach
- 1. Design of Gear boxes Presented by Mr. C. Gururaj, AP(SG)/Mechanical Engg. Ramco Institute of technology, Rajapalayam. E mail – gururaj@ritrjpm.ac.in Mobile- 9940999961
- 2. UNIT IV GEAR BOXES Geometric progression - Standard step ratio - Ray diagram, kinematics layout -Design of sliding mesh gear box - Design of multi speed gear box for machine tool applications - Constant mesh gear box - Speed reducer unit. – Variable speed gear box, Fluid Couplings, Torque Converters for automotive applications.
- 3. Various methods used for obtaining different speeds 1. By using gear boxes 2. By using cone pulley arrangements 3. By using a variable speed electric motor. 4. By hydraulic operation Gear boxes Gear box is device which is employed between the prime mover and machine shaft for giving deferent number of speeds to the machine spindle.
- 4. REQUIREMENTS OF A GEAR BOX 1. It should provide the designed series of spindle speeds. 2. It should transmit the required amount of power to the spindle. 3. It should provide smooth silent operation of the transmission. 4. It should have simple construction 1. (https://www.youtube.com/watch?v=wCu9W9xNwtI) 2. https://youtu.be/MXsRfbOiBhE
- 5. PREFERRED NUMBERS These numbers are conventionally rounded off values derived from geometric series. EX: R5, R10, R20, and R40 Each series has its own step ratio For example R5 has the step ratio of = 1.6 5 10
- 6. PSG Data book page number 7.20
- 7. why the speeds in gear boxes in geometric series (The speeds in gear boxes can be arranged in arithmetic progression (A.P), Geometric Progression (G.P), Logarithmic Progression (L.P)) 1. Speed loss is minimum 2. Number gears employed in minimum 3. G.P provides more range of speeds 4. Layout is comparatively compact 5. G.P machine tool spindle speeds can be selected easily from preferred numbers.
- 8. STEP RATIO OR SERIES RATIO OR PROGRESSION RATIO (Φ) Ratio between two adjacent speeds is known as step ratio 12 3 1 2 ....... n n N N N N N N )%1(10 1 1 nn N N )%1(10 Permissible deviation
- 9. Find the progression ratio for a 12 speed gear box having speeds between 100 and 355 rpm. Also find the spindle speeds.
- 10. Select the spindle speeds for the following data 12 speeds between50 and 600 rpm
- 11. Select spindle speeds for 9 spaced gear box between 80 and 1285 rpm.
- 13. Structural formula or stage formula n = p1(X1) . p2(X2) . p3(X3)
- 15. Ray diagram – Graphical representation of the structural formula
- 16. BASIC RULES FOR DESIGNING GEAR BOX
- 17. A nine speed gear box used as a head stock gear box of a turret lathe is to provide a speed range of 180 rpm to 1800 rpm. Using standard step ratio draw the speed diagram, kinematic layout. Also find and fix the number of teeth on all gears. Also calculate the percentage deviation of the obtainable speeds from the calculated ones.
- 18. Construction of Ray diagram Structural formula 3(1) 3(3) Number of vertical lines ( number of shafts) = no of stages +1 Number of horizontal lines = Number of speeds (n) 3(1) 3(3) Stage 2Stage 1 Shaft1 Shaft2 Shaft3 180 236 315 425 560 750 1000 1320 1800 Stage 2 N min = 180 ; N max = 1000 1 4 2
- 19. Kinematic arrangements Shaft 1 Stage1Stage2 Shaft 2 1 2 3 4 5 6 7 8 9 10 11 12 Shaft 3
- 21. Calculation of Number of teeth on each gear
- 28. The overlapping speed gear box Full design of gear box In the pdf format
- 29. References: Dr. V. Jayakumar, “Design of Transmission Systems” Laksmi Publications, Chennai, Chapter No. 9