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Info Letter No. 48 - April 1998

Copyright by HEXAGON Software 1998


ZAR1+ Manufacturing Drawing

As for pressure springs, the spur gear calculation now includes a complete drawing form with all necessary table values for the gearing manufacture. Changes are entered in ZAR1+ and then transfered to the change index on the drawing. It is now also possible to link company "documents" to any program, e.g. for additional information, CAD drawings, working plans, etc. The drawing can be generated as a DXF or IGES file and then transfered to CAD. Or, you can use our additional program, DXFPLOT to print the drawing out directly on a plotter or laser printer. I would like to thank Mr Henzler, Mr Duerrscheidt and Mr Layer of Robert Bosch, Murrhardt, Germany for this idea.




ZAR1/ZAR1+ Tool Root Concave Rounding

The new version of ZAR1 and ZAR1+ allows entry of a root concave rounding value (rhoFPO/mn) for the datum profile of the gearing tool. Over-cutting tools, when used to finish the outside diameter (kmn=0) of the gear, may result in rounding off on the tooth tip. The rounding off has no influence on the finished tooth when there are a small number of teeth with a positive addendum modification coefficient. I would like to thank Mr Koerner of Voith Turbo in Heidenheim, Germany for this suggestion and the documentation.




ZAR1+ Data Base Datum Profile

The fields RFP (tool root concave rounding), ALPHA (pressure angle) and MODUL (normal modulus) have been added to the data base Z1TOOL which is now available under the new file name Z1TOOLX. The information fields NR, D, B and ART can be filled with an internal company drawing number, diameter, width and type. A warning appears when the modulus from the data base does not match the normal modulus of the calculation.


WL1+ Export Excel

The diagram values can now be saved as text files under "Export Diagram". These text files can then be opened under Excel, Star-Office, etc., and be used as spread sheets. In WL1+ the buckling calculation for axial forces can now be deactivated under "Edit->Calculation", this reduces calculation time.

WL1+ Surface Moment of Inertia

The axial surface moment of inertia for shaft sections is no longer provided. Until now, Iy has only been provided for cylindrical sections, as it is variable for conical shaft sections. The formula for calculating the surface moment of inertia of circular ring sections is as follows:
Iy = pi/64 * (De^4 - Di^4)


DBFEDIT for Editing the Data Base

Under the "Database" Menu, you can alter and append all the data bases delivered with the calculation programs. However, the built-in DBF editor is a little difficult to use. As an alternative you can use an external data base. In order to do this you configure an external data base program under "File->Settings->External Programs". Enter the file name and the directory path for the program. We are offering an editor for the DBF files. The editor is called DBFEDIT and is available free of charge, on the internet under "www.hexagon.de/history/tools/". There is a version "dbfedi16.zip" for Windows 3.1, "dbfedi32.zip" for Windows 95 and NT. DBFEDIT has an advantage over the earlier editor "DBBROWSE" in that it doesn't require the "Borland Data Base Engine" to work. DBFEDIT can be integrated into the calculation program. The integration of any external data base program is possible with all Windows versions of HEXAGON software since June 1996.




SR1 - Drawing

By using our calculation program DXFPLOT, you can print out a drawing of the calculated bolted joint on a plotter or laser printer with all the important dimensions and calculation results. Print out is also possible via the DXF or IGES interface to CAD. Drawing data (name, date, replaced...) and changes can be entered under the sub-menu "Document".



SR1 - Tensile Strength Auxiliary Lines

Auxiliary lines up to breaking point are shown as dashed lines in the M-alpha and FM-MA diagrams. The lines are displayed as dashed because the program cannot take the additional remaining overstrain into account as shown on the stress-expansion diagram occuring after the yield point.

SR1 - Fatigue Limit

Until now the calculation has generally used the values and formula from VDI 2230 (diagram 48) to calculate the permissible endurability of the bolt. Since the values are only applicable to finished tempered bolts of the durability classes 8.8, 10.9 and 12.9, you can now alternately enter the alternating strength Sigma A. Or select MAT_B_SA.DBF from the data base. The value Sigma A, can be entered in the data base as the function of the thread diameter. For this information and documentation I would like to thank Mr Ralph Shoberg of RS Technologies, Farmington Hills, USA.




WN2 - Manufacturig Drawing

It is now possible to generate a drawing with a table of the most important toothing data for the tooth shaft and hub. As for the spring programs, WN1, SR1 and ZAR1, drawing data and changes can be entered under the sub-menu "Documentation". Links to other documents can also be generated. I would like to thank Mr Wesierski of Somatec, Giesendorf in Germany for this idea.




Diagrams - Configurable Limits

The scale of the y axis of diagrams is calculated by the program in accordance to the greatest and smallest values in order to create a diagram which fills the available format. In order to compare several calculations by laying the diagrams on top of each other the scale start and end values must be identical. In the new versions (Windows only) you can determine the scale start and end values of the x and y axis under "CAD->Diagrams". With "Calculate" you can calculate the program-suggested values before doing this. The new option can also be used to show sections (zoom window).

The input window only appears when you have checked the box "Diagram Limits" under "File->Settings->Graphic". I would like to thank Mr Wirth of Wirth-Springs in Undeloh, Germany for this suggestion.


Spring Programs - Excerpt

A table including spring loads, travels, lengths, stresses and safety margins is included in the spring programs' short printouts. This can sometimes be confusing because the stress correction factor k is taken into account for dynamically loaded springs with the indeces 1 and 2, whereas for the usable length n, and block length c, it is not taken into account. Due to this, it can occur that a higher stress is shown for tauk2 than for taukn, although the spring path L2 is smaller than Ln. For the application there must be enough safety for the elevation stress Sh=taukhzul/taukh and for the upper stress S2=tauzul/tauk2. When the spring is inserted under block, a (static) safety margin Sc=tauzul/tauc>=1 must exist. In order to better demonstrate the relationship with and without the stress factor k, two additional lines have been added to the dynamic load which show the dynamic factor k's increased values for the positions n and c.


Dynamically Loaded Compression Spring Excerpt
De = 17˝0.15 mm     d = 2˝0.035 mm     w = 7.5     k = 1.18

n = 9.235     nt = 11.24     nt-n = 2

tauz = 876 N/mm▓     tauhz = 570 N/mm▓     Rm = 1565 N/mm▓
       
======================================================================
Spr.Length.mm   Spr.Path mm   Spring Load N       tau N/mm▓       S
======================================================================
L0=  38.00˝0.89
L1=  35.00      s1=   3.00    F1=   15.27˝4.69    tauk1=   86    10.14
                sh=   7.00    Fh=   35.63         taukh=  202     2.83
L2=  28.00      s2=  10.00    F2=   50.91˝5.03    tauk2=  288     3.04
Ln=  27.97      sn=  10.03    Fn=   51.05         taukn=  289     3.03
Ln=  27.97      sn=  10.03    Fn=   51.05         taun =  244     3.59
Lc=  22.86      sc=  15.14    Fc=   77.06         taucn=  436     2.01
Lc=  22.86      sc=  15.14    Fc=   77.06         tauc =  368     2.38
----------------------------------------------------------------------
                                                 (S = tau zul. / tau y)
For all springs, the index n stands for the usable spring path. The definition for compression springs however, is completely different to that for extension and torsion springs. For compression springs the usable spring travel is defined as the block spring travel minus a safety margin Sa. For extension and torsion springs the spring travel or spring angle at which the permissible shearing or bending stress is attained. For compression springs, tau n can be greater or smaller than tau zul, but for extension and torsion springs tau n is always equal to tau perm or sigma n is equal to sigma perm. The table in FED2+ and FED3+ has been appended by the stress correction values. However, the reduced spring path, spring forces and spring moments at which the permissible stress under dynamic load are attained, are shown instead of the increased stress for sn. Excerpt of a dynamically loaded extension spring:
De = 10.05˝0.25 mm     d = 1.3˝0.015 mm     w = 6.73     k = 1.21

tauz = 777 N/mm▓     tauhz = 397 N/mm▓     Rm = 1726 N/mm▓

======================================================================
Spr.Length.mm   Travel   mm   Spg.Force N         tau N/mm▓       S
======================================================================
L0=  27.47˝0.8                F0=    8.47         tau0 =   86
L1=  39.98      s1=  12.51    F1=   45.62˝5.38    tauk1=  559     1.39
                sh=  10.00    Fh=   29.69         taukh=  364     1.09
L2=  49.98      s2=  22.51    F2=   75.31˝5.83    tauk2=  923     0.84
Lkn= 45.96      skn= 18.49    Fkn=  63.38         taukn=  777     1.00
Ln=  50.41      sn=  22.94    Fn=   76.58         taun =  777     1.00
----------------------------------------------------------------------
                                                (S = tau zul. / tau y)
Dynamically Loaded Torsion Spring Excerpt
Dm = 20.49˝0.484mm    d = 1.4˝0.025 mm    w = 14.63    q = 1.10

n(if) = 1.833   a = 0 mm    LK0 = 4.038˝2.108 mm     E = 206000 N/mm▓

sigma z = 1523

======================================================================
Install.Angle°      Spring Angle°   Torque Nmm           Sigma N/mm▓
======================================================================
delta0= 329.9˝17.0  alfa0=   0.0    T0=    0.00          sigma0 =   0
delta1= 307.0       alfa1=  22.9    T1=  130.00˝84.34    sigmaq1= 530
                    alfah=  30.0    Th=  170.00          sigmaqh= 693
delta2= 277.0       alfa2=  52.9    T2=  300.00˝84.34    sigmaq2=1223
deltaqn=264.0       alfaqn= 65.9    Tqn= 373.71          sigmaqn=1523
deltan= 257.5       alfan=  72.4    Tn=  410.30          sigman =1523
----------------------------------------------------------------------



FED6 - Pitch

Gradient has been added to the spring section table in the quick output.




FED2 - Curled Eyes and Bolts

The length LH, for curled hooks, bolts and screw latches applies to the distance from the clamping point at the beginning of the springy coils (not curled coils). A new auxiliary picture has been created for this. When selecting pictures 10 through 13, the number of curled end coils is required for the calculation of the wire length and weight. For this idea I would like to thank Mr Himmer of Hirsch Springs in Marktredwitz, Germany.




HPGLMAN, HPGLVIEW: Windows NT Driver

Files plotted with HP-GL/2 under Windows NT were shown back-to-front in HPGLVIEW and HPGLMAN. The driver's SC command caused this unusual scaling. The files are now shown correctly.


Compressed Printout

The reduction of pages printed out in the compressed printout is due to the separating lines not being printed. In addition, the last page was missing when printed on Windows' printers. This error has been corrected and now all pages are printed out.


HEXAGON Demo Software in Decker Machine Elements

The newest edition of the specialist book "Decker Machine Elements" (German: Decker Maschinenelemente, Publisher: Hanser, ISBN 3-446-19382-0) includes a CD ROM containing demo versions of all HEXAGON programs and a student version of WL1 along with Excel spreadsheets for calculation examples. The book can be obtained at a price of DM 69.80 from HEXAGON, book shops or directly from the publisher: Hanser, www.hanser.de/fachlit/ .


Decimal Point: Comma instead of Point

It is now possible to configure in all programs whether the comma or point should be used to display decimals. This is especially important when exporting tables to Excel, Quattro Pro, etc. Depending on the language or settings a point or a comma may be used.
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