Torsion Spring Component Generator dialog box - Calculation tab

Sets parameters for calculation of a torsion spring.

Access:

Ribbon: Design tab Spring panel Torsion and click the Calculation tab.

Spring Strength Calculation

Torsion Spring Design	Designs dimensions of the torsion spring for the specified spring load.
Spring Check Calculation	Calculates the assembly dimensions and a tension spring strength check for the specified load and spring dimensions.
Work Forces Calculation	Calculates the forces induced by the torsion spring of the specified dimensions.

Calculation Option

Select the options for spring calculation.

Direction of Spring Load	A Load Coils the Spring	The spring is loaded in the direction of coils winding.
	A Load Uncoils the Spring	The spring is loaded in the direction of coils unwinding.
Design Type	Note: This option is available only if you select Torsion Spring Design in the Spring Strength Calculation area.
	F 8 , Assembly Dimensions d, n, D, F 1	Designs suitable wire diameter, number of coils, spring diameter, and minimum load for the specified maximum load and assembly dimensions of the spring.
	F, ϕh d, n, D, Deflections	Designs suitable wire diameter, number of coils, spring diameter, and angular deflections of working arm for the specified load and angle of working stroke.
	F, D d, n, Assembly Dimensions	Designs suitable wire diameter, number of coils and assembly dimensions are designed for the specified load and torsion spring diameter.
	F 8 , D, ϕ*h d, n, F1, Deflections	Designs suitable wire diameter, number of coils, angular deflections of working arm and minimum load for the specified maximum load, angle of working stroke and torsion spring diameter.
Method of Stress curvature correction	Use the drop-down list to select the method of stress curvature correction.
	With helical springs, the stress appearing in the spring coils at the given loading is calculated for simple torsion. Additional bending stress appears in the coil due to its rounding. Therefore, the stress is corrected in the calculation using a correction coefficient. As several different coefficients are commonly used, choose from the list the correction coefficient which meets your local usage or recommendations of standards.
	Note: In view of strength check of a spring exposed to static loading, using the correction coefficient from Gahner gives the best results.
	Hint: With springs exposed to static loading, corrections are not executed.

Loads

This option is not available if you select Work Forces Calculation in the Spring Strength Calculation area.

Calculate the Moments	The spring working forces are calculated for the specified bending moments and the arm length.
Calculate the Forces	The bending moments are calculated for the specified spring working forces and the arm length.

Spring Mounting

Check the box to enable to input or measure values.

Perform the dimension check of spring rod and housing.

Dimensions

Enter or measure the spring dimensions.

Spring Coils

Rounding of Coil Number	Set the value for rounding the coil number value.
Active Coils Number	Specify the spring number of active coils.

Spring Material

Select the spring material and its properties. Click to open the Material Database where you can select the appropriate material.

Warning: Strength parameters of material are determined empirically and reflect minimum values applicable for a group of materials. Although these values are close to the values obtained using measurement of particular materials, it is recommended in cases of final calculations to use the parameters of material according to the material sheet or specifications of the producer.

Material	Specifies material values you enter or select from the Material Database.
	If a material is selected from the Material Database, its values are inserted automatically into the following edit fields, and the edit fields are locked. To unlock the field clear the box.
Allowable Bending Stress	Enter the modulus of allowable bending stress of the spring material.
Modulus of Elasticity	Enter the modulus of elasticity of the spring material.
Density	Enter the density of the spring material.
Utilization of Material	Enter the utilization factor of the spring material. Click the arrow next to the edit field where you can set the value.
	The coefficient gives a relation between the torsion stress of a spring in the fully loaded state and the allowable torsion stress, such as u S » τ 8 / τ A . If a greater value is selected, less material is needed for spring production and the spring dimensions and the space for mounting are less, but the securing of spring stability during its function is lower, and vice versa. Therefore, this coefficient is a reciprocal value of the safety rate. For common operational conditions, the value of the utilization factor of the material is recommended to be within the u S = 0.85 ... 0.95 range. Lower values can be used for springs working in aggressive surroundings, at high temperatures or loaded with impacts.
	The value of the utilization factor of the material is selected in a dialog box where a range of recommended values is designated.

Assembly Dimensions

ϕ1, ϕh ϕ8	Calculates the maximum angular deflection of working arm for the specified angle of working stroke and minimum angular deflection of working arm.
ϕ8, ϕh ϕ1	Calculates the minimum angular deflection of working arm for the specified angle of working stroke and maximum angular deflection of working arm.
ϕ1, ϕ8 ϕh	Calculates the angle of working stroke for the specified angular deflections of working arm.

(More)

Displays additional options for spring design. To display the More Options area, click More in the right lower corner of the Calculation tab.

Design of Working Stoke Angle
Note: This area is available only if following two options are selected: Torsion Spring Design in the Spring Strength Calculation area, and F, D d, n, Assembly in the Design Type drop-down list.
Not Specified	Designs suitable angle of working stroke for the specified load and spring diameter.
Minimum Angle	Designs suitable angle of working stroke that is larger than the minimum allowable value for the specified load and spring diameter.
Maximum Angle	Designs suitable angle of working stroke that is smaller than the maximum allowable value for the specified load and spring diameter.
Angular Range	Designs suitable angle of working stroke that is the nearest to the required angle for the specified load and spring diameter.
Design of Spring Diameter
Note: This area is available only if following two options are selected: Torsion Spring Design in the Spring Strength Calculation area, and F 8 , Assembly Dimensions d, n, D, F 1 ; or F, ϕ h d, n, D, Deflections in the Design Type drop-down list.
Not Specified	Designs the smallest suitable spring diameter for the specified load and spring assembly dimensions.
Minimum Diameter	Designs the smallest suitable spring diameter larger than the minimum allowable value D2min for the specified load and spring assembly dimensions.
Maximum Diameter	Designs suitable spring outside diameter smaller than the maximum allowable value D1max for the specified load and spring assembly dimensions.
Diameter Range	Designs suitable spring diameter nearest to the demanded diameter D' for the specified load and spring assembly dimensions.

Results

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

Displays the calculated dimensions values such as spring mass or wire length. Click Calculate to display the values. The units of the results values can be changed. Double-click the specified value you want to change.

Following output parameters are displayed in the Results pane:

• Results
  • Min. Load Bending Stress of the Spring Material (σ ₁ )
  • Max. Load Bending Stress of the Spring Material (σ ₈ )
  • Length of Mx. Load Coiled Part (L ₈ )
  • Spring Max. Load Inside Diameter (D ₂₈ )
  • Stress Concentration Factor (k _f )
  • Spring Rate (kϕ)
  • Limit Test Angle Deflection of Working Arm (ϕ _max )
  • Deformation Energy (W ₈ )
  • Wire Length (l)
  • Spring Mass (m)

Note: For further description of the calculated parameters in metric and English units, see 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