Gear manufacturing methods

Gear manufacturing methods (poly)

1. GEAR CUTTING BY KHATIK T.R . SPC Sangola, Dis-Solapur

2. Universal Gear D ividing H ead

3. Types of Dividing Head 1.Plain and simple Dividing Head 2.Universal Dividing Head 3. Helical Dividing Head 4.Optical Dividing Head

4. Indexing Methods -Definition -Types of Indexing method 1.Direct Indexing method 2.Plain / simple Indexing method 3.Compound Indexing method 4.Differiantial Indexing method 5.Angular Indexing method

5. 1.Direct Indexing Direct Indexing (Rapid Indexing) is the simplest form of indexing. Used for quick indexing of work piece. The direct indexing plate is mounted on the nose of the dividing head spindle which also carries the work. The number of divisions required by direct indexing is limited by the number of holes/slots in the direct indexing plate. Direct indexing plates are available with 24, 30 and 36 holes or slots. It is possible to index any number of divisions which is a factor of total holes/slots in the plate

6. 1.Direct Indexing in Universal Dividing Head To perform this type of indexing, the worm shaft must be disengaged from the worm gear wheel . Since most direct indexing plate have 24 holes, all divisions which are factors of 24 (24, 12, 8, 6, 4, 3, 2) can be produced with this plate. Indexing data = N  T N – No. of holes in Indexing Plate T – No. of required divisions Example : What is the index movement required to mill 8 slots on a workpiece? N  T = 24  8 = 3 (3 holes on a 24 hole circle)

7. 1.Direct Indexing Whenever starting to machine the first hole, it is necessary to make sure that the indexing pin is in the hole or slot No. Zero or 24 of the indexing plate. After doing the necessary indexing movement, it is required to clamp the indexing spindle so that the cutting force will not go onto the indexing plate and indexing pin.

8. 2.Plain Indexing (or) Simple Indexing Used for divisions beyond the range of direct indexing Universal Dividing Head is used for this The Indexing plate should be locked with the body Worm and worm gear is to be engaged Dividing head is rotated by turning the index crank and locked at the next indexed hole on the plate

9. Plain or Simple Indexing 40 turns of indexing crank = 1 revolution of index head spindle Index plates with concentric circles of holes: Plate: 1 - 15, 16, 17, 18, 19, 20 Plate: 2 - 21, 23, 27, 29, 31, 33 Plate: 3 – 37, 39, 41, 43, 47, 49 Index crank movement = 40/N (N = number of divisions required) For cutting 30 teeth, 40/30 = 1 + 1/3 = 1 + 7/21 (One complete turn of indexing crank and 7 holes in 21 hole circle of the index plate)

10. 3.Differential Indexing This method is used for divisions that could not be indexed by simple indexing The required division is obtained by combination of: Movement of the index crank similar to simple indexing Simultaneous movement of the index plate when the crank is turned The rotation of the index plate may be in the same direction or opposite to the crank rotation

11. Differential Indexing Lock pin is disengaged to permit rotation of index plate A sleeve with bevel gear is connected to the index plate The sleeve and the bevel gear are free to rotate on the worm shaft Another bevel gear engages with it and the shaft of that gear has change gears that mesh with the gear mounted on the back of the main spindle Crank rotates the spindle Spindle’s motion is transmitted to index plate through change gears

12. Rule for Differential Indexing Gear Ratio = Driving gear/Driven gear (= Gear on the spindle/Gear on the bevel gear shaft ) = (A-N) X 40/A where: N = The required number of divisions to be indexed A = a number nearer to N which can be indexed by plain indexing (assumed number) 2. Index Crank Movement for each division = 40/A (Index crank is to be moved by this amount for N number of times for complete division of the work)

13. Rule for Differential Indexing 3. Number of idlers in the change gears: If (A-N) is positive, the index plate must rotate in the same direction as the crank If (A-N) is negative, the index plate must rotate in the opposite direction to the crank To achieve the correct direction of rotation, number of idle gears is obtained as follows: A-N Simple gear train Compound gear train Positive One idler No idler Negative Two idlers One idler

14. Rule for Differential Indexing Change gears with following numbers of teeth are generally supplied: 24, 24, 28, 32, 40, 44, 48, 56, 64, 72, 82, 100 With these gears and the three sets of standard index plates, it is possible to index any number from 1 to 382.

15. 5.Angular Indexing Angular indexing is the process of dividing the periphery of a work in angular measurements and not by the number of divisions. Indexing method is similar to plain indexing One complete turn of crank will cause the spindle and the work to rotate through 360/40 = 9◦ Index crank movement = Angular displacement in deg/9 Angular displacement in minutes/540 Angular displacement in seconds/32400

16. Gear shaping (pinion cutter) Gear planing (Rack cutter) Gear hobbing Gear generating methods

17. Gear shaping

18. Gear shaping

19. Gear shaping

20. Gear shaping

21. Gear Planing Rack

22. Gear Planing with a rack cutter

23. Gear Planing with a rack cutter

24. Gear Hobbing Hobbing is a process of generating a gear using a rotating tool called “Hob”. The hob has helical threads The threads have grooves cut parallel to the axis to provide cutting edges. The gear teeth are cut into the workpiece by a series of cuts made by the hob. It is the most widely used gear cutting process for creating spur and helical gears.

25. Gear Hobbing Gear hobbing is a multipoint machining process in which gear teeth are progressively generated by a series of cuts with a helical cutting tool (hob).  Both the hob and the workpiece revolve constantly as the hob is fed across the face width of the gear blank. They rotate in a timed relationship A proportional feed rate is maintained between the gear blank and the hob Several teeth are cut on a progressive basis It is used for high production runs

26. Hobs

27. Gear Hobbing

28. Gear Hobbing

29. Gear Hobbing

30. Gear Generating comparison

31. Gear Hobbing

32. Gear Hobbing

33. Gear Hobbing

34. Gear Hobbing

35. Gear Hobbing

36. Gear Hobbing

37. Gear Hobbing

38. Vertical Hobbing Machine

39. Vertical Hobbing Machine

40. Various Gear Cutters

41. Gear Shaving

42. Gear Shaving Cutter

43. Gear Grinding

44. Gear Grinding