This page contains a Flash digital edition of a book.
AUTOMOTIVE GEARMAKING


to accurately grind asym- metrically. “We believe we are the fi rst to market to do this for asymmetric gears,” he said. Available on the Liebherr LCS- and LGG- platforms, he also noted that these machines can also provide the completely new development called generated end-relief (GER). Until now, end relief in gear grinding was only available with the much slower profi le grinding method, where each tooth is ground indi- vidually. The GER grinding has a similar effect—gears can now be designed with


Gear manufacturers are increasingly designing asymmetric gears, allowing higher loads with less NVH. Liebherr developed a generating grinding process that solves the complex machine movements needed to grind such gears.


shorter face widths (i.e., lighter weight) but still carry the same loads. Perhaps the most exciting new technology for addressing NVH is what Yoders describes as Noise Excitation Optimization, or NEO, developed in a part- nership with the Technical University of Munich “This is similar to noise cancel- lation in that we grind into the teeth a specifi c wave- length and amplitude of the form error, both in lead and profi le direction on the gear tooth,” he explained. This introduces, on pur-


pose, a defi ned and engineered “waviness” in the profi le form deviation (commonly defi ned as ffɲ) and lead form deviation (commonly defi ned as ffβ). Yoders presented audio data in an interview with SME that dramatically demonstrated a gear with signifi cantly less gear whine after NEO correction. Other gear manufacturing equipment suppliers have noticed the increasingly stringent technical requirements in automotive. “I think if you were to speak to an automotive engineer about transmissions, they would say the difference between the quality of the transmission [today] and one from seven or eight years ago is something like 500%,” said Scott Knoy, vice president of sales for German Machine Tools of America (GMTA; Ann Arbor, MI). A unique process from GMTA that helps provide that accuracy is their trademark scudding process.


What is scudding? “Think of it as a cross between hob- bing and shaving,” explained Knoy: A continuous generat- ing process using a multipoint tool that eliminates issues such as the spacing error known as drop tooth. “There are no idle strokes on the machine tool, as you get with the gear shaping process,” he said. He also noted that it prob- ably will not completely replace shaving, since it requires a cross-axis angle that prevents the process from getting as close to a shoulder as shaving. “It is especially useful in increasing the quality of the green machining, so that after heat treating you do not have to do as much honing or grinding,” Knoy said. “Presenting a more accurate part after


66 AdvancedManufacturing.org | May 2016


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146  |  Page 147  |  Page 148  |  Page 149  |  Page 150