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# Info Letter No. 129 - Sept. / Oct. 2011

#### by Fritz Ruoss

ZAR1+ Roll Angle

A new table with roll angles for several diameters between start and end of involute is available at "View->Table->Roll Angle".

ZAR1+, 2, 3+, 5, 6: Material in Production Drawing

Material of gear wheels has been added in production drawings.

FED1+ Temperature Data in Diagrams

Numerical values of shear modulus and spring load F1, F2 for calculated temperature as well as for min and max value of defined temperature range have been added to the temperature diagrams.

FED1+ Self-Defined tolerances in Production Drawing to EN 15800

Self-defined tolerances are listed in field 10 of the production drawing to EN 15800 now.

FED1+ Quick3 View with FQ and External Mass, Production Compensation

Radial load FQ and external mass m are displayed in Quick3 View, if defined at "Edit->Application"

Dimensions that are selected as production compensation, are no longer included in the table with quality grades.

New Software for O Ring Calculation

A new software for calculation of O Ring pressure in pneumatic and hydraulic applications will be available soon.

GEO3 - Hertzian Pressure and Deformation on Path Load

For combinations cylinder-cylinder and cylinder-plain exists no analytic solution for calculation of deformation w0 (and spring rate R). At "Edit->Calculation Method", you can now choose between different approximate computations for calculation of deformation w0 (= approach of both bodies). Besides the former formula of a geometrical calculation from half length of contact axis and radius of cylinder, you can choose calculation according to several formulas according to Arnell, Ina, Lundberg, Kunert and Palmgren. Default setting is 0 (no calculation of w0 and R, only pressure (pmax) and dimensions of pressure rectangle (a) will be calculated).

GEO3 - Abbreviations and Symbols

In literature about Hertzian pressure, various abbreviations and symbols can be found for the same Terminology. Approach of the center of the two bodies under load, for example, is defined as deformation, flattening, and approach with symbol w, w0 and delta. GEO3 now uses consistently the symbols from "Dubbel Handbook of Mechanical Engineering" with these modifications:

- Deformation w changed into w0.

- half length of contact axis (half length of pressure ellipse) a1 and a2 changed into a and b.