KISSsoft Tutorial-Lifetime analysis of cylindrical gears

1 Task

1.1 Task

To analyze the strength of a cylindrical gear pair as specified in ISO6336,method B.A load spectrum is used in this example. The safety factors, service life and permissible power rating are to be calculated.

The following data is specified for this cylindrical gear pair:

2 Calling the program

2.1 Starting the software

You can call KISSsoft as soon as the software has been installed and released. Usually you start the program by clicking "Start→Program Files→KISSsoft 03-2011→KISSsoft". This opens the following KISSsoft user interface:

Figure 2.1 Starting KISSsoft, initial window

3 Entering the data

3.1 Inputting the load spectrum

KISSsoft provides a range of different options for you to input load spectra. If the load spectrum is stored in the database it is also available to other calculations.In contrast, if you use the"Own input" option to enter the load spectrum, it is only available to the current calculation.

3.1.1 Database: direct entry

After you have opened the database tool as shown in Figure 3.2 with authorization to write data to it (you may have to run KISSsoft as the Administrator), you now have a range of options for defining load spectra in the database. Select "Load spectra" from the list and click on "Edit" to call the appropriate table.

Figure 3.3 Generating a new data record

Click "+" to create a new data record. If a data record is marked, its data is copied and "_NEW" is attached to its label. If no data record is marked, a new one will be created. Now enter a description.

You now see information about the "frequency, power or torque and speeds" for the corresponding load level elements.You can also specify whether the load spectrum refers to the torque or the transmitted power. Once you have finished entering data for this load spectrum, click "OK" and then click "Save" to save this data record. Then click "Close" to close the database tool and return to the KISSsoft system's initial screen. The load spectrum is now available for analysis.

Figure 3.4 Inputting the load spectrum

3.1.2 Database: data input from a file

You can also transfer a load spectrum to the database as a file. To do this, enter the required load

spectrum in a text editor as shown below:

Frequency Torque/Power/ Speed

For example:

0.1 0.2 0.2

0.2 0.3 0.5

0.4 0.9 0.8

0.3 1.0 1.0

This file is saved as a file with the file extension *.dat (in this example "Example-Tut-010.dat", for preference in the ...\KISSsoft 03-2011\ext\DAT folder (for more information,see Figure 3.5) or in any other folder (for more information see Figure 3.6).

In the KISSsoft installation folder you will find a folder called C:\Program Files\KISSsoft 03-2011\ext\DAT. If you store files with the file extension *.dat in this folder, the KISSsoft system will be able to find them automatically. In this case, you only need to enter the following:

Figure 3.5 Inputting the file description in which the load spectrum was saved

If you save the file with the load spectrum to a different folder, you must also store the entire path + file name in the "File name" field. If the path name is too long, follow the steps described above:

3.1.3 Own input

After you have clicked the Figure 3.7 plus button as shown in , you can now define load spectra in the database using the "Own input"function. Click the plus buttonto call the "Input load spectrum" window. Here you can either input a load spectrum directly or load it from a file. Then click "OK" to assign the load spectrum to the calculation.

Figure 3.7 Calling "Own input" load spectrum

3.2 Inputting toothing data

To call the cylindrical gear calculation, go to the modules tree window in the KISSsoft main screen.

There, click the "Modules" tab and then click"Cylindrical gear pair [Z012]".Then input the toothing data specified below:

Figure 3.8 Inputting toothing and load data

(1) Reference gear

(2) Load: here you must input two of the three values (speed, torque, power)

(3) Calculation method

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KISSsoft Tutorial-Tooth Form Optimizations Part A

KISSsoft Tutorial-Tooth Form Optimizations, Tooth Form Modifications specifically for Plastic, Sintered, Wire-eroded and Form-forged Gears

1 Introduction

1.1 Summary of the design strategy

These instructions describe a strategy for optimizing the design of gears that are manufactured

using moulding methods (injection moulding, sintering, forging etc.). These special methods for

sizing and optimizing gears manufactured using these methods are integrated in the KISSsoft calculation software.

The sizing process involves these steps:

- Define the approximate sizes (module, face width, etc.) using the strength calculation

- Define allowances

- Optimize tooth height (aim: achieve effective transverse contact ratio 2.0 whist taking

into account tip rounding, running-in curve for noise reduction)

- Tip-rounding

- Optimize running-in curves/profile correction (aim: improving the wear safety factor)

- Optimize root fillet (increased the root safety factor)

- Determine a mould for the manufacturing process

1.1 Introduction

Nowadays,gears are increasingly manufactured from plastics because the development of new materials has made them able to achieve increasingly higher load capacities. The special

properties of plastics allow them to be used in many more areas than steel. A designer can therefore select the best possible material for their particular application. In doing so, they define the most important properties of a gear pair, such as load capability, resistance to wear, compression ratio, stiffness and noise emissions.

Metallic gears are usually manufactured in a milling process. In contrast, plastic gears are

usually injection moulded. If the mould is produced by a wire erosion process, the tooth form can be optimized at no additional cost. In a milling process, this is only possible with expensive, specialist tools.However, the injection moulding process does not achieve a particularly good toothing quality and, once again, this is a problem that can only be solved by implementing specific measures. Gears that have been modified in this way are referred to as hybrid tooth forms in the technical literature.

The KISSsoft calculation software includes a large number of special methods for sizing and

optimizing plastic gears. These procedures are fully integrated into a comprehensive, modern

software system that enables you to develop and monitor both standard and hybrid tooth forms.

2 Defining tooth geometry

2.1 Introduction

You can change tooth geometry in many different ways to achieve the optimum ratio of tooth contact. Depending on the importance of the targets to be achieved, such as low noise emission, low vibration, strength, sliding, balance, you must prioritize the measures to be taken. When you start this optimization process, we recommend you set the following defaults:

2.2 Tip-rounding

For tooth forms produced using a moulding process, the tooth tip edges must be rounded,because corners can never be created accurately in injection moulding. It is a good idea to input this data in the main screen for gear 1 and gear 2. As a result, all the most important data (such as contact ratio, etc.) will then be calculated to include tip-rounding.

This is now illustrated in an example: The KISSsoft system has a tutorial file for this calculation.

This is "Tutorial - 011". Open this file in the cylindrical gear calculation module:

Figure 2.1 Opening cylindrical gear calculation and the tutorial file

Figure 2.2 Example file for plastic gears, after calculation ("")

Click in the tool bar or press "F5" to calculate the tooth form data. Without tip-rounding the

contact ratio would be 1.6680. You can see the tooth form as a graphic in the lower part of the

window. You can also view the tooth form here and move it to the required position (see the marking on the lower right of Figure 2.2).

Figure 2.3 Tooth form display

You should now save the tooth form locally. To do this, open the "Property browser" (1). Activate the tooth form of Gear 1 (2) and click the "Save" button (3). This opens an information window. Here you can make any necessary changes (for example, color) and additional entries (4). Then click "OK" (5) to save Gear 1's tooth form. Follow this procedure again to save Gear 2's tooth form. You can now view the changes you have made to the tooth form. Then, close the "Property browser".

Figure 2.4 Saving the tooth form

To define the tip-rounding, go to the "Modifications" tab (see the uppermost marking in Figure

2.5) and input the relevant values for Gear 2 and Gear 5:

Figure 2.5 Defining tip rounding, here 2 mm radius

Then click onto apply the changes. If you look carefully at the graphic, you will see the rounding on the teeth. The original tooth form is also displayed (in black/green or blue).

Figure 2.6 Rounded tooth tip

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KISSsoft Tutorial-Tooth Form Optimizations Part B

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KISSsoft Tutorial-Tooth Root Optimization

1 Overview

1.1 Task

This tutorial shows how tooth root geometry influences tooth strength and how it can be optimized. It recommends you use the "Graphical method" if you want to study the root strength of non-standard root geometry.

To do this, you use the strength calculation and tooth geometry calculation.

1.2 Results

Three different root geometries are to be examined:

1. resulting root geometry, with a tool root radius factor P=0.38

2. resulting root geometry, with a tool root radius factor =0.45

3. optimized root geometry (elliptical rounding)

The following results for safety factors are found when you use a combination of ISO 6336 and

ISO 6336 and the "Graphical method":

Table 1.1 Comparison of calculated safety factors for tooth root bending strength safety factors

depending on method As you can clearly see, by optimizing the root geometry, the safety factor against bending failure has been increased by 16%. However, this optimized root rounding requires a special tool (modified cutter). For this reason, we recommend you use this method for mass production (e.g. by form grinding) or if the gears are manufactured by wire erosion or sintering.

*Note: if you use the unmodified ISO 6336 method (or other methods like DIN 3990 or AGMA

2001) you cannot estimate a modified root geometry. You can see this because the results from Geometry 2 to Geometry 3 do not change.

1.3 Theory

The value fP is the radius of the root of the reference profile of the gear as shown below:

Figure 1.1 Reference profile of the gear,

The strength rating specified in ISO 6336 uses only a single point in the root where factors YF

and YS are calculated.This point is defined by the contact between a tangent to the root intersecting the symmetry line at a 30° angle and the root itself. YF and YS are then calculated as shown in formulas (2) and (3). The resulting root stress is then calculated in accordance with formula.

Figure 1.2 Calculating the tooth root stress as specified in ISO 6336

The actual construction of the root rounding therefore implies a larger or smaller degree of error.

KISSsoft therefore includes a modification in the calculation methods, allowing for the calculation of YF and YS factors along the whole of the root. In this case, the point at which the

product of YF*YS reaches the maximum is taken as the point where the strength rating is performed.

This is the only method that allows you to evaluate the effect of optimized root roundings.

1.4 Other contents of this tutorial

In section 2, the root safety factor is calculated according to the unmodified ISO 6336 method

(Method B). However, you cannot use this method to take into account the effect of root optimization. The root safety factor is therefore only calculated for Geometry 1 and 2.

In section 3, the root safety is then calculated using the graphical method (an optional modification to ISO 6336 by KISSsoft). Here you can clearly see the effect of optimized root rounding.

The comparison between the calculated results is shown in Table 1.1

Further explanations and comments are given in section 4.

All calculations/changes are performed only for Gear 1.

2 Strength calculation as specified in ISO6336

2.1 For Geometry 1 (=0.38)

To open the example used in this tutorial, click "File/Open" and select "CylGearPair 1 (spur gear)" or click the "Example" tab.

Figure 2.1 Open example calculation "CylGearPair 2 (spur gear)"

The selected calculation method is ISO 6336, Method B. To check which reference profile was

used, click the "Reference profile" tab. In this example a standard reference profile (1.25/0.38/1.00) as specified in ISO 53.2 profile A has been used.

Figure 2.2 Selected calculation method

Figure 2.3 Standard reference profile as used for first calculation

Figure 2.4 Result of calculating the safety factor of the tooth root stress in Gear 1

The resulting tooth form is displayed in a graphics window. Click the button (upper right marking) to make it into a floating window and enlarge it. You can save the tooth forms so they can be compared later on. To do this, follow the steps marked in Figure 2.5

Figure 2.5 Resulting tooth form with =0.38

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KISSsoft Tutorial-Compression Springs as Specified in EN 13906

1 Starting KISSsoft

1.1 Starting the software

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.

1.2 Selecting a calculation

In the Modules tree window, select the "Modules" tab to call the calculation for compression springs:

Figure 1.2 Selecting springs, compression springs.

2 Analyzing Compression Springs

2.1 Task

To analyze a cold formed compression spring 4 x 40 x 235 made of spring steel. Search for this

data:

?

This tutorial then describes how you input the following data:

Table 2.2 Operating data.

2.2 Inputting operating data

As shown below, you can input operating data directly in the input window. Here you can input

either the forces or the ways.

Figure 2.1 Input window, "Operating data" group.

The types of support are displayed in a help graphic that you open by clickingnext to the

Support field. The support coefficient v is used for calculating the buckling spring travel sk. If the required level of buckling safety is not achieved, the spring must be led, otherwise it will buckle.

If the spring must be led, the KISSsoft system issues a warning message when you perform

the calculation to inform you of this fact.

Figure 2.2 Warning shown if the spring will buckle and must be led.

Figure 2.3 Types of support with the corresponding support coefficients.

2.3 Inputting the geometry and selecting materials

The KISSsoft database includes a wide range of different compression springs, all of which

correspond to the specifications in DIN 2098, supplementary sheet 1. You can select the spring

you require directly from this list. This example uses a spring selected from this list.

However, if the spring you require is not present, simply select "Own Input" and input your own parameters for a spring. You will find more detailed information about this below.

To find a suitable spring, first click "Update". The system now calculates and displays values

that match your input, such as spring travel, spring forces. This helps you make the best possible choice.

Click the right-hand mouse button in the spring selection list to determine which values are to be displayed.

Figure 2.4 Input window, "Geometry" group - spring selection.

You can then either select or input the shape of the spring ends, the manufacturing method and

the tolerances in the area below the table.

Figure 2.5 Clicking the right-hand mouse button to select the values to be displayed.

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KISSsoft Tutorial-Bolt Analysis in Accordance with VDI 2230

1.1 Starting the software

Once you have installed and activated KISSsoft either as a test or licensed version, follow these steps to call the KISSsoft system. Usually youstart the program by clicking"Start?Program FilesKISSsoft 03-2011?KISSsoft". This opens the following KISSsoft user interface:

Figure 1.1 Starting KISSsoft, initial window

1.2 Selecting a calculation

In the Modules tree window, select the "Modules" tab to call the calculation for bolts:

Figure 1.2 Selecting the "Bolts" calculation module

2 Calculation of a flanged connection

2.1 Task

Size and verify the bolting for a flanged coupling using the following data:

The connection is made using through bolts (notation as specified in VDI 2230:2003 - bolted joint) with nuts, and with washers under the nuts and under the bolt head. Input this data in the "Basic data" tab as follows:

Figure 2.1 Inputting known data, selecting the calculation method

2.2 Proposal for a reasonable bolt diameter

After you have defined the load and input the basic data for the bolt, click the "Sizing button"

in the main window and the program proposes values for a suitable bolt diameter.This proposal is based on a simplified bolt layout as specified in VDI 2230: 2003. This method usually results in over-dimensioned bolts. Experience shows that the minimum permitted bolt diameter is often one or two sizes smaller! Note the message that appears when you click the Sizing button. If you click the Sizing button, the software suggests a bolt diameter that is based on VDI 2230: 2003.

2.3 Defining the nuts and washers

In the "Basic data" tab, you can now input the data for the nuts and washers:

Figure 2.5 Calling the subscreens for defining washers and nuts

Figure 2.6 Defining the nut and washers. (The values for the diameter etc. do not appear until you input the data)

2.4 Defining clamped parts

The "Clamped parts" tab contains all the details about clamped parts. As a flanged connection is being calculated,the software recommends you define the geometry of the clamped parts (flange) as segments of an annulus:

Figure 2.7 Note: define "segments of an annulus" when calculating flange connections

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