Machine element or mechanism – Gearing – Teeth
Reexamination Certificate
2000-04-19
2001-12-04
Fenstermacher, David (Department: 3682)
Machine element or mechanism
Gearing
Teeth
C074S457000, C074S462000, C072S324000, C029S893350
Reexamination Certificate
active
06324931
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to gears and method for manufacturing thereof in general, and particularly to straight bevel gears having improved tooth root geometry and a method for manufacturing a forging die for making thereof.
BACKGROUND OF THE INVENTION
Straight bevel gears are used for many automotive applications, such as differential gearing. Currently, gear manufacturers employ a number of various method for making gears. Recently, forging technology has achieved tremendous development and become very popular. Compared to machining, forging has its advantages of improving the product quality by achieving a high stiffness in the material without cutting the material flow lines, good surface condition at the formed part, and work hardening that increases wear resistance, and quick cycle time suitable for mass production.
Forging die design is essential for the manufacturing of the gear because it determines the shape of the gear and, therefore, performance of the gearing incorporating this gear. Currently, forging dies for straight bevel gears are generated by a gear cutter. Thus, root area of the straight bevel gear is determined by the cutter edge radius. The current method of making the gear cutter is not optimizes a cutter edge radius, which creates stress concentration in a gear root area.
SUMMARY OF THE INVENTION
The present invention alleviates the drawbacks of the prior art.
The present invention provides a method for designing gear tooth profiles. An important element of this invention is a technique for defining a root area profile of the gear tooth that provides reduced stress concentration and improved durability over the current designs. The present invention discloses mathematical equations determining the position of any point on the surface of the gear root area.
In accordance with the preferred embodiment of the present invention, the bevel gear is manufactured by die forging. The method for manufacturing the gear forging die is contemplated in the present invention. This method includes the steps of: (a) determining a gear root area geometry, (b) designing a straight bevel gear having the gear root area geometry as determined in the previous step, (c) designing an electrode for an electric discharge machining (EDM) on a CAD/CAM device using numerical data from the step (b), (d) manufacturing said electrode for the electric discharge machining, and (e) manufacturing said forging die employing the electric discharge machining process using said electrode. Thus, the present method eliminates the need in the gear cutter, and the forging die manufactured in accordance with the present method more closely corresponds to the profile of the originally designed gear.
REFERENCES:
patent: 2961888 (1960-11-01), Wildhaber
patent: 3298219 (1967-01-01), Schober
patent: 3675459 (1972-07-01), Dohman
patent: 3731516 (1973-05-01), Dohman et al.
patent: 5052210 (1991-10-01), Hoge
patent: 5271289 (1993-12-01), Baxter, Jr.
patent: 5275046 (1994-01-01), Nagpal et al.
patent: 5396160 (1995-03-01), Chen
patent: 5453933 (1995-09-01), Wright et al.
patent: 5552995 (1996-09-01), Sebastian
patent: 5680317 (1997-10-01), Watanabe
patent: 5787753 (1998-08-01), Dougherty
patent: 5896643 (1999-04-01), Tanaka
Dana Corporation
Fenstermacher David
Liniak Berenato Longacre & White
LandOfFree
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