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Coefficient of friction at screw thread is the ratio defining the force that resists the motion of the nut in relation to the threads in contact with it. Check FAQs
μ=2Mtlo+Wdmtan(α)sec(0.2618)(Wdm-2Mtlotan(α))
μ - Coefficient of friction at screw thread?Mtlo - Torque for lowering load?W - Load on screw?dm - Mean Diameter of Power Screw?α - Helix angle of screw?

Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread Example

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Here is how the Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread equation looks like with Values.

Here is how the Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread equation looks like with Units.

Here is how the Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread equation looks like.

0.15Edit=22960Edit+1700Edit46Edittan(4.5Edit)sec(0.2618)(1700Edit46Edit-22960Edittan(4.5Edit))
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Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread Solution

Follow our step by step solution on how to calculate Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread?

FIRST Step Consider the formula
μ=2Mtlo+Wdmtan(α)sec(0.2618)(Wdm-2Mtlotan(α))
Next Step Substitute values of Variables
μ=22960N*mm+1700N46mmtan(4.5°)sec(0.2618)(1700N46mm-22960N*mmtan(4.5°))
Next Step Convert Units
μ=22.96N*m+1700N0.046mtan(0.0785rad)sec(0.2618)(1700N0.046m-22.96N*mtan(0.0785rad))
Next Step Prepare to Evaluate
μ=22.96+17000.046tan(0.0785)sec(0.2618)(17000.046-22.96tan(0.0785))
Next Step Evaluate
μ=0.150037705075024
LAST Step Rounding Answer
μ=0.15

Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread Formula Elements

Variables
Functions
Coefficient of friction at screw thread
Coefficient of friction at screw thread is the ratio defining the force that resists the motion of the nut in relation to the threads in contact with it.
Symbol: μ
Measurement: NAUnit: Unitless
Note: Value should be between 0 to 1.
Torque for lowering load
Torque for lowering load is described as the turning effect of force on the axis of rotation that is required in lowering the load.
Symbol: Mtlo
Measurement: TorqueUnit: N*mm
Note: Value should be greater than 0.
Load on screw
Load on screw is defined as the weight (force) of the body that is acted upon the screw threads.
Symbol: W
Measurement: ForceUnit: N
Note: Value should be greater than 0.
Mean Diameter of Power Screw
Mean Diameter of Power Screw is the average diameter of the bearing surface - or more accurately, twice the average distance from the centreline of the thread to the bearing surface.
Symbol: dm
Measurement: LengthUnit: mm
Note: Value should be greater than 0.
Helix angle of screw
Helix angle of screw is defined as the angle subtended between this unwound circumferential line and the pitch of the helix.
Symbol: α
Measurement: AngleUnit: °
Note: Value should be greater than 0.
tan
The tangent of an angle is a trigonometric ratio of the length of the side opposite an angle to the length of the side adjacent to an angle in a right triangle.
Syntax: tan(Angle)
sec
Secant is a trigonometric function that is defined ratio of the hypotenuse to the shorter side adjacent to an acute angle (in a right-angled triangle); the reciprocal of a cosine.
Syntax: sec(Angle)

Other Formulas to find Coefficient of friction at screw thread

​Go Coefficient of Friction of Screw given Effort for Trapezoidal Threaded Screw
μ=Pli-(Wtan(α))sec(0.2618)(W+Plitan(α))
​Go Coefficient of Friction of Screw given Torque Required in Lifting Load with Trapezoidal Thread
μ=2Mtli-Wdmtan(α)sec(0.2618)(Wdm+2Mtlitan(α))
​Go Coefficient of Friction of Screw given Effort in Lowering Load
μ=Plo+Wtan(α)Wsec(0.2618)-Plosec(0.2618)tan(α)
​Go Coefficient of Friction of Power Screw given Efficiency of Trapezoidal Threaded Screw
μ=(tan(α))1-ηsec(0.253)(η+(tan(α))2)

Other formulas in Trapezoidal Thread category

​Go Effort Required in Lifting Load with Trapezoidal Threaded Screw
Pli=W(μsec((0.2618))+tan(α)1-μsec((0.2618))tan(α))
​Go Load on Screw given Effort Required in Lifting Load with Trapezoidal Threaded Screw
W=Pliμsec((0.2618))+tan(α)1-μsec((0.2618))tan(α)
​Go Helix Angle of Screw given Effort Required in Lifting Load with Trapezoidal Threaded Screw
α=atan(Pli-Wμsec(0.2618)W+(Pliμsec(0.2618)))
​Go Torque Required in Lifting Load with Trapezoidal Threaded Screw
Mtli=0.5dmW((μsec((0.2618)))+tan(α)1-(μsec((0.2618))tan(α)))

How to Evaluate Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread?

Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread evaluator uses Coefficient of friction at screw thread = (2*Torque for lowering load+Load on screw*Mean Diameter of Power Screw*tan(Helix angle of screw))/(sec(0.2618)*(Load on screw*Mean Diameter of Power Screw-2*Torque for lowering load*tan(Helix angle of screw))) to evaluate the Coefficient of friction at screw thread, Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread formula is defined as the ratio of the tangential force that is needed to start or to maintain uniform relative motion between two contacting surfaces to the perpendicular force holding them in contact. Coefficient of friction at screw thread is denoted by μ symbol.

How to evaluate Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread using this online evaluator? To use this online evaluator for Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread, enter Torque for lowering load (Mtlo), Load on screw (W), Mean Diameter of Power Screw (dm) & Helix angle of screw (α) and hit the calculate button.

FAQs on Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread

What is the formula to find Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread?
The formula of Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread is expressed as Coefficient of friction at screw thread = (2*Torque for lowering load+Load on screw*Mean Diameter of Power Screw*tan(Helix angle of screw))/(sec(0.2618)*(Load on screw*Mean Diameter of Power Screw-2*Torque for lowering load*tan(Helix angle of screw))). Here is an example- 0.150038 = (2*2.96+1700*0.046*tan(0.0785398163397301))/(sec(0.2618)*(1700*0.046-2*2.96*tan(0.0785398163397301))).
How to calculate Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread?
With Torque for lowering load (Mtlo), Load on screw (W), Mean Diameter of Power Screw (dm) & Helix angle of screw (α) we can find Coefficient of Friction of Screw given Torque Required in Lowering Load with Trapezoidal Thread using the formula - Coefficient of friction at screw thread = (2*Torque for lowering load+Load on screw*Mean Diameter of Power Screw*tan(Helix angle of screw))/(sec(0.2618)*(Load on screw*Mean Diameter of Power Screw-2*Torque for lowering load*tan(Helix angle of screw))). This formula also uses Tangent (tan), Secant (sec) function(s).
What are the other ways to Calculate Coefficient of friction at screw thread?
Here are the different ways to Calculate Coefficient of friction at screw thread-
  • Coefficient of friction at screw thread=(Effort in lifting load-(Load on screw*tan(Helix angle of screw)))/(sec(0.2618)*(Load on screw+Effort in lifting load*tan(Helix angle of screw)))OpenImg
  • Coefficient of friction at screw thread=(2*Torque for lifting load-Load on screw*Mean Diameter of Power Screw*tan(Helix angle of screw))/(sec(0.2618)*(Load on screw*Mean Diameter of Power Screw+2*Torque for lifting load*tan(Helix angle of screw)))OpenImg
  • Coefficient of friction at screw thread=(Effort in lowering load+Load on screw*tan(Helix angle of screw))/(Load on screw*sec(0.2618)-Effort in lowering load*sec(0.2618)*tan(Helix angle of screw))OpenImg
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