1 Task
1.1 Task
A helical gear pair is to be designed such that it has a service life of 5,000 h when transmitting 5 kW at 400 rpm (application factor = 1.25) The ratio shall be 1:4 (reducing speed) and 18CrNiMo7-6 is to be used as the gear material. The helical gear pair is to be optimized to achieve the best possible noise/contact ratio. Strength calculation is to be performed as specified in ISO 6336 Method B.
1.2 Starting gear pair calculation (helical gear pair)
Once you have installed and activated KISSsoft either as a test or licensed version, follow these steps to call the KISSsoft system. Usually you start the program by clicking "Start?Program Files?KISSsoft 03-2011?KISSsoft". This opens the following KISSsoft user interface:
Figure 1.1 Starting KISSsoft, initial window
In the Modules tree window, select the "Modules" tab to call the "cylindrical gear pairs" calculation:
Figure 1.2 Calling cylindrical gear calculation
To open the example used in this tutorial, click "File/Open" and select "Tutorial-009-Step1" (to
"Tutorial-009-Step5") or click the tab in the "Example" window. Each section in this tutorial describes which file you need to open (as shown below).
Figure 1.3 Options for opening the example files used in this tutorial at different stages of progress
2 Rough sizing of a gear pair
2.1 Calling the Rough sizing function
Use the Rough sizing function to create a sensible initial layout for a cylindrical gear stage. To
do this, input the required key data after you call the Rough sizing function by clicking "Calculation"→"Rough sizing" in the Rough sizing screen.
To access this stage of the calculation directly, open the "Tutorial-009-Step1" file
Figure 2.1 Calling Rough sizing
Here it is essential that you define the required ratio (including any permitted variation in % (here 5%)) and input the transmissible power and the material. You can also predefine the required helix angle or center distance. The helix angle depends on the type of bearing used with the shaft. The helix angle may be larger or smaller, depending on how much axial force the bearings can support. The helix angle can be optimized later on during Fine Sizing. Here, in the Rough sizing function, you should only input an approximate value for the helix angle, or "zero" for a spur gear. You can input additional information in the "Rough sizing" input window in the "Geometry" group. For example, the number of teeth on the pinion, the geometry proportions and the center distance.
Figure 2.2 Input window Rough sizing group: "Geometry" ? Conditions Number of teeth, gear 1
Click the "Details" button in the "Rough sizing" input window in the "Strength" group to predefine the safety factors that are to be achieved.
Figure 2.3 Input window Rough sizing group: "Strength" ? Conditions safeties
Click the ìCalculate-button and the KISSsoft system will calculate different solutions for a gear
pair that fulfills the specified conditions. These solutions are then displayed in the list shown below.
Figure 2.4 Cylindrical gear-Rough sizing, results
To select one of these solutions, (here with a center distance of 107 mm), click on it in the list
and then click the "Accept" button. Then click "Close" to close the list.
To access this stage of the calculation directly, open the "Tutorial-009-Step2" file
Figure 2.5 Normal module, number of teeth, width, profile shift and center distance as proposed by the KISSsoft system
2.2 Modifications
You can now modify the proposed values, for example, for the gear width you can input a pinion width of 28 mm, or a gear width of 27 mm (directly in the appropriate fields). You can also change the reference profile in the drop-down list in the "Reference profile" tab.
Figure 2.6 "Reference profile" tab, information about the reference profile
To modify the profile shift of gear 1 (gear 2 will then be calculated to match), click the Sizing button
to open the "Sizing of profile shift coefficient" dialog window in the lower figure. This window contains proposed values for various different profile shift coefficients (see Figure 2.7):
Figure 2.7 Dialog window; size profile shift coefficients
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