1 GEARS MACHINING GEAR TYPES Cylindrical gears: -spur -helical Bevel gears: -straight -curved...
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1 GEARS MACHINING GEAR TYPES Cylindrical gears: -spur -helical Bevel gears: -straight -curved (spiral) Worm wheels and worms Slide 2 2 Involute tooth profile Slide 3 3 Spur and helical gears cutting METHODS: form milling using a cutter (with the same edge profile as the shape of the tooth space) and a dividing device hobbing using a hob and a generating process for creating a tooth profile shaping using a shaper cutter and a generating process for creating a tooth profile broaching Slide 4 4 Gear machining form milling (single gear tooth cutter) Slide 5 5 Gear machining form milling Slide 6 Gear milling tollerances and surface finish Type of cutITRa Form milling shape mill 9 113,2 - 6,3 End milling8 - 93,2 - 6,3 Slide 7 7 Gear machining - hobbing Hob a tool designed as a worm shaped cutter, which acts by the cutting as a worm cooperating with the machined gear wheel Slide 8 8 Hobbing cutter Slide 9 9 Gear hobbing Slide 10 10 Gear hobbing Slide 11 11 Gear hobbing machine tool Slide 12 12 Gear hobbing machine tool Slide 13 13 Gear hobbing kinematic schema Slide 14 14 Gear machining - shaping circular shaper cutter rack shaper cutter Slide 15 15 Gear shaping a circular cutter Slide 16 16 Gear shaping a circular cutter Slide 17 17 Gear shaping the principle Slide 18 18 Gear shaping a circular cutter Slide 19 19 Gear shaping a rack cutter Slide 20 20 Gear shaper with the rack cutter Slide 21 Tollerances and surface finish Type of cutITRa Hobbing 5 - 70,8 3,2 Shaping circular cutter 5 60,8 1,6 Shaping rack cutter 4 - 50,8 1,6 Slide 22 Broaching Very productive method Broach has the shape of gear Ideal for internal gears Tooth gaps one after another All gaps simultaneously Desc.: 1 elongated body, 2 teeth, 3 gullets, 4 teeth gaps, 5 axis, 6 follower end, 7 pull end, 10 outside shape of broach Slide 23 Broaching From a premachined hole a final gear is made Slide 24 Broaching Type of cutITRa Roughing5 60,8 1,6 Finishing4 - 50,8 1,6 Slide 25 25 Spur and helical gears finishing METHODS: shaving for gears without heat treatment grinding mostly for gears after heat treatment - form grinding - involute - generating grinding lapping teeth rounding creating a shape of tooth (in the direction parallely to the axis of rotation) to make changing gears easier Slide 26 26 GEAR WHEELS SHAVING A gear wheel being shaved is run in contact with a shaving cutter Shaving cutter HSS tool; teeth with serrations, which are acting in the shaving Slide 27 27 GEAR WHEELS SHAVING The gear and the cutter are run in mesh with their axes crossed at a small angle. During the rotation the gear is reciprocated longitudinally across the cutter. This shaving process causes very fine chips are cut from the tooth surface (process requires less than 1 minute) Slide 28 28 Form gear grinding Slide 29 29 Form splining grinding Slide 30 30 Involute-generating grinding Slide 31 31 Involute-generating grinder Slide 32 32 Involute-generating grinder Slide 33 Gear finishing tollerances and surface finish Type of cutITRa Shaving5 - 60,4 0,8 Form grinding5 70,2 1,6 Involute-generating grinding with straight-sided grinding wheels 2 - 40,2 0,4 Involute-generating grinding with a worm grinding wheels 3 - 50,2 - 0,8 Slide 34 Gear lapping On finished, shaved and hardened gears. The gear runs in contact with one or more cast iron lapping gears Flow of oil with abrasive is used Improves surface quality at low costs then grinding Ra = 0,1 0,2 Slide 35 35 Teeth rounding Slide 36 36 Teeth rounding Slide 37 37 Straight bevel gears cutting METHODS: form milling using a cutter (with the same form as the tooth face) and creating first one, than the opposite face flank of the tooth involute-generating milling using two cutters representing one tooth of a rack and a generating process for creating a tooth profile shaping using a shaping rack tool and a generating process for creating a tooth profile broaching using rotational broach Slide 38 38 Straight bevel gears involute-generating milling Slide 39 39 Straight bevel gears - shaping Slide 40 40 Straight bevel gears - broaching Slide 41 41 Straight bevel gears - broaching Slide 42 42 Curved bevel gears cutting METHODS: Gleason teeth curved in the form of circle Oerlikon teeth curved in the form of epicycloid Klingelnberg teeth curved in the form of involute Slide 43 Gleason method Tool is a composition of a round body and cutting tools. The can be adjusted separatelly. Slide 44 44 Curved bevel gears - Oerlikon Slide 45 45 Curved bevel gears - Oerlikon Slide 46 Worms and worm gears Worms produced by turning or form milling Slide 47 Worms and worm gears Worm gears produced by hobbing Worm hob has a small diameter In feed machining Slide 48 Odkazy youtube Form milling http://www.youtube.com/watch?v=s4F8XzV8IrMhttp://www.youtube.com/watch?v=s4F8XzV8IrM 5axis http://www.youtube.com/watch?v=RV8Dq6mslnE&feature=fvw Gear hobing http://www.youtube.com/watch?v=DwFssm9trSc&feature=related http://www.youtube.com/watch?v=2HfCxlSP0-g&feature=related http://www.youtube.com/watch?v=j7dEtrN6TqM&feature=related Gear shaping http://www.youtube.com/watch?v=xF9CjluRFJ4&feature=fvw http://www.youtube.com/watch?v=_j6KQ96YZM0&feature=related Bevel gear planing http://www.youtube.com/watch?v=Adi0GgUc2Z4&NR=1 Gleason bevel cutting http://www.youtube.com/watch?v=Qq-0CePTt98&feature=related http://www.youtube.com/watch?v=jSYP1wTp4T4&feature=related Worm turning http://www.youtube.com/watch?v=b81qJcZ9eTI&feature=related 48 Slide 49 Odkazy youtube Gear grinding http://www.youtube.com/watch?v=m6gRprNkTkY Gear rounding http://www.youtube.com/watch?v=0xMYSXa7fsA&feature=related 49