Roller Chains Generator dialog box - Calculation tab

Sets calculation parameters for a chain.

Use the Calculation tab to apply design rules to perform strength check analysis as well as provide recommendations for the Design tab.

Access:

Ribbon: Design tab Power Transmission panel Roller Chains and click the Calculation tab.

Working Conditions

Use the drop-down menu to select which properties of a driving machine are known. Note: According to the selected option, appropriate edit fields are enabled or disabled.
Torque, Speed Power	Calculates the power according to the torque and speed.
Power, Torque Speed	Calculates the speed according to the power and torque.
Power, Speed Torque	Calculates the torque according to the power and speed.
Efficiency	Specify expected efficiency of the chain drive. The usual efficiency is 0.98 [-].
Required service life	Change required service life from the default 15,000 hours. Click the arrow to open a dialog box where you can select the value.
Maximum chain elongation	Specify maximum allowable chain elongation. The elongation is given in percent of the chain length. The value "0.02 ul" means elongation of “2%†of the chain length.
Application	Use the drop-down list to select from the most common applications for chain drives. The application selection informs the generator about the amount of typical overload. The application type affects the Shock factor and Service factor. Both factors can be manually adjusted, as needed.

Environment	Specify environmental conditions for a chain drive.
	Clean	No abrasive dust appears in the environment (indoor application).
	Soiled	Abrasive dust might occur in the environment (outdoor application).
Lubrication	Specify the lubrication type.
	Recommended	The generator recommends an appropriate lubrication method based on the rules (rules based on a chain size and speed). You can see the recommended lubrication within the Summary of messages group box.
	No lubrication, Manual, Drip Feed, Bath or Disc, Forced Feed	Set the lubrication, lubrication factor is determined accordingly. Note: Some of the options are not valid for fast speed chain drives. Calculation fails for invalid inputs.

Chain Properties

Sets mechanical properties of the selected chain because the same size and type of the chain might differ across manufacturers. Check the box to insert the appropriate value.
Tensile strength	The ultimate tensile strength of the chain is the maximum load that can be applied before the chain breaks. There are dynamic and static safety factors that reduce the permissible working load. The default value comes from standard recommendations for a given chain size, but you might want to consult this parameter with specifications provided by your chain supplier. The tensile strength can differ for the same size of the chain among different chain producers as well as different materials of the chain.
Specific mass	Specific mass of the chain depends on the chain size, construction, and material. The default value is taken from standard recommendations or the closest value of steel chains produced by chain manufacturers. The specific mass is used for computing centrifugal force and for vibration analysis.
Chain power rating	Chain power rating represents chain capacity rating for normal operating conditions. It is compared with the required design power to predict if the chain works for given operating conditions. If operating conditions differ from normal, the comparison is corrected by power correction factors. to customize the chain power rating, consider customization of Chain construction factor at first. Also, consider customization of sprocket size power correction factor. If your customized chain power rating is fixed for given number of teeth of the smallest sprocket you might want to keep sprocket size factor equals to 1.0. If the customized chain power rating does not consider size of the smallest sprocket, you might want to let the generator advise the sprocket size factor for you. You can customize this factor as well. Note: See the Engineering Handbook for more details on chain power rating.
Chain construction factor	Describes the actual quality of the chain. It directly affects the default chain power rating and chain permissible bearing area pressure. If the factor value is 1, it does not affect standard size both of these properties. Consider modifying this factor if your chain is made from material with better strength or the quality of the chain is actually better than mentioned in national standards.

Power Correction Factors

A list of customized parameters that affect working conditions and tells the generator how much the current operating conditions differ from normal. You can modify any power correction factor. Editing requires a good knowledge of chain drive design, see Engineer's Handbook for more details on power correction factors. Check the box to display an appropriate dialog box to edit the factor values.

Limit Chain Bearing Area Pressure

Check the box to enable the strength check within roller and bush area of the chain. If you clear the check box, the stress within chain bearing area is not part of strength check. However, the actual stress is still calculated based on working conditions. If the option is selected, the allowable stress is determined and compared with actual stress calculated based on working conditions. If the comparison fails, the entire strength check fails. See Engineer's Handbook for more details.
Permissible pressure	Permissible pressure in chain bearing area is defined for normal operation conditions. For specific operation condition, the total permissible pressure is multiplied with specific friction factor and is compared with actual pressure in chain bearing area.
Specific friction factor	Specific friction factor corrects permissible pressure in chain bearing area. The size of the correction depends on how much the actual operating conditions differ from normal.

Vibration Analysis

Controls the critical speed of the driver sprocket with respect to natural frequencies of the chain spans. For certain speed and drive setting, vibrations can appear within the chain drive. Such vibrations can result in significant reduction of chain drive service life. Check the boxes before Chain stiffness and Limit of critical speed to enter their values manually. See Engineer's Handbook for more information about vibration analysis.
Chain stiffness	Chain stiffness is the force required to elongate chain of its unit length. The property is used to determine critical driver speed which is close to the natural frequencies of the chain strands. The default value can differ for specific chain construction and material.
Limit of critical speed	If the chain speed is close to the critical resonance speed, it can result in unexpected additional load in chain drive what can significantly reduce chain drive service live. The error message is displayed if the actual driven sprocket speed is in critical interval.

(More)

Displays additional options for chain drive design. To display the More Options area, click More in the right lower corner of the Calculation Tab.
Recommended safety factors
	Static	Minimum value of static factor of safety determined for constant load. If the actual value of static factor is smaller than this minimum value, the strength check fails. See engineering handbook for more details.
	Dynamic	Minimum value of dynamic factor of safety determined for peak load. If the actual value of dynamic factor is smaller than this minimum the strength check fails. See engineering handbook for more details.
	Lubrication factor impacts just power rating limited by galling between pins and bushings	This option affects the determination of the design power and chain power rating. This option can be considered if the lubrication is not sufficient for given operating conditions and therefore the lubrication factor differs from 1.0. If the option is switched on, the lubrication factor impacts the chain power rating limited by galling between pins and bushings. If the option is switched off, the lubrication factor affects directly design power. See the Engineering Handbook for more details.

Results

To display the Results area on the right side of the Design and Calculation tabs, double-click the double line on the right or click the chevron.

Displays the calculated values. Click Calculate to display the values. The units of the results values can be changed. Double-click the specified value you want to change.

The following output parameters are displayed in the Results pane:

• Design power (P _D )
• Effective pull (F _p )
• Centrifugal forcer (F _C )
• Maximum tension in chain span (F _Tmax )
• Static safety factor (S _S )
• Dynamic safety factor (S _D )

Note: For more information on the calculated parameters, see the Engineer's handbook

Summary of Messages

Displays the reports about calculation. To open the Summary of Messages area at the bottom of the Calculation and Design tabs, double-click the double line at the bottom of tabs or click the chevron at the bottom of the tabs.

Toolbar commands