Worm Gear - Helical Wheel Pairs: Interchangeability Standards - Ghiringhelli - #1

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Page 1 Ghiringhelli S.r.l. I – 20091 Bresso (MI) Via Vittorio Veneto 109 Tel. ++39-02-6108941 Fax.++39-02-6104748 E-mail: info@ghiringhelli-srl.com Web Site: www.ghiringhell-srl.com C.F.-P.I.: 00840170153 C.C.I.A.A. Milano n. 175647 Tribunale di Milano n. 159718/3896/18 Worm Gear - Helical Wheel Pairs: Interchangeability Standards Foreword Cylindrical gears with involute teeth have tooth profiles which are manufatured to precise specifications. We are able to produce these elements when we receive the production drawings with all the necessary technical information. The manufacture of the single elements of the worm gear-wheel pairs is difficult because the profile of the teeth is not specified. Technical and Manufacture Variables In the worm-wheel pairs the teeth present profiles with approximate geometric curves: the drive profiles are very variable and the drawings cannot be precise enough. In addition each manufacturer uses his own “personalised” profiles on the basis of the available equipment. The variables, which are taken into account in the manufacture of these sets, are many and, besides the data which are specified in the drawings, there are other factors which interact on the worm-wheel drive: · Type of profile (A, K, N, I ) determined by the method of cutting or grinding the worm. · Diameter of the tool which cuts the helical wheel: the diameter of the tool decreases after sharpening and this produces a new profile.