Name: friction torque in collar bearings
Uploaded: 2023-09-22T11:49:30.000Z
Duration: 1 min 23 s
Channel: JoVE

Les roulements à collier sont un type de roulement utilisé dans les machines pour supporter des charges axiales sur des arbres en rotation, il peut avoir un ou plusieurs colliers.
Considérons un roulement à collier unique soumis à une charge axiale. La zone entre le rayon externe et le rayon interne du collier est la surface totale de contact du roulement.
En supposant un support uniforme pour le roulement, la pression normale uniforme peut être exprimée comme le rapport de la force sur la surface du roulement.
Considérons un élément d’aire infinitésimale sur le relèvement. La force agissant sur l’aire différentielle peut être exprimée comme le produit du coefficient de frottement, de la pression et de l’aire différentielle.
Le moment nécessaire pour provoquer une rotation imminente de l’arbre est déterminé à partir de l’équation d’équilibre des moments autour de l’axe de rotation.
Ensuite, l’intégration est utilisée pour déterminer le moment appliqué nécessaire pour surmonter toutes les forces de frottement.
Enfin, en substituant les valeurs de la force différentielle et de l’aire différentielle et en intégrant l’équation sur la surface totale du palier, le moment de l’arbre peut être estimé.

<ol>
	<li>Hibbeler, R.C. (2016). Génie mécanique \u2012 Statique et dynamique. Hoboken, New Jersey : Pearson Prentice Hall. Pages 447 et 448.</li>
</ol>

roulement de collier

Les roulements de collier sont essentiels dans diverses machines conçues pour supporter des charges axiales sur des arbres rotatifs. Selon l'application spécifique et les exigences, ils peuvent être trouvés avec un ou plusieurs colliers. <img alt="Figure 1" src="/files/ftp_upload/14325/14325_Figure_1v3.svg" style="text-align: center; height: 300px;"> Considérez un roulement de collier simple soumis à une charge axiale. La surface de contact totale du roulement est la région entre le rayon externe et le rayon interne du collier. Lorsque l'on suppose que le roulement fournit un support uniforme, la pression normale uniforme peut être calculée en divisant la force appliquée sur le collier par la surface de contact totale du roulement. Cette valeur représente la distribution moyenne de pression sur la surface du roulement. Pour analyser davantage les forces agissant sur le roulement de collier, considérez un petit élément de surface infinitésimal sur la surface du roulement. La force agissant sur cet élément infinitésimal est le produit du coefficient de frottement, de la pression et de la zone différentielle. Comprendre la relation entre ces variables est crucial pour calculer le moment nécessaire à la rotation de l'arbre. La rotation imminente de l'arbre est déterminée en analysant l'équation d'équilibre des moments autour de l'axe de rotation. Cette équation prend en compte toutes les forces et les moments agissant sur l'arbre, y compris les forces de frottement générées par le roulement de collier. <img alt="Equation 1" src="/files/ftp_upload/14325/14325_Equation_1v2.svg" style="text-align: center; height: 39px;"> En intégrant l'équation, le moment appliqué nécessaire pour surmonter toutes ces forces de frottement peut être déterminé, ce qui initie la rotation de l'arbre. Enfin, pour estimer le moment de l'arbre, substituez les valeurs de force différentielle et de zone dans l'équation intégrée. <img alt="Equation 2" src="/files/ftp_upload/14325/14325_Equation_2v2.svg" style="text-align: center; height: 55px;"> En intégrant cette équation sur la surface totale du roulement, on obtient une compréhension complète des forces et des moments agissant sur le roulement de collier et du moment requis pour la rotation de l'arbre. <img alt="Equation 3" src="/files/ftp_upload/14325/14325_Equation_3v2.svg" style="text-align: center; height: 39px;">

Roulement de collier

Les paliers lisses sont essentiels dans diverses machines conçues pour supporter des charges axiales sur des arbres en rotation. En fonction de l’application spécifique et ...

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Mechanical Engineering

Génie mécanique

Unit 1

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Friction

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Collar Bearings

friction torque in collar bearings

Collar bearings support axial loads on rotating shafts, and their friction helps determine the torque needed to start motion. They are used in many machines and may have a single collar or multiple collars, depending on the application and load needs.

For a single collar bearing under an axial load, the contact area is the ring-shaped region between the external radius and the internal radius of the collar. If the bearing is assumed to support the load evenly, the uniform normal pressure is found by dividing the applied force by this total bearing contact area. This gives the average pressure across the bearing surface.

To study the forces more closely, a small infinitesimal area element is considered on the collar surface. The force on that tiny area equals the friction coefficient times the pressure times the differential area. Using this relationship is important for finding the moment required to rotate the shaft.

The impending rotation of the shaft is found by writing the moment equilibrium equation about the rotational axis. This equation includes the forces and moments on the shaft, along with the frictional forces from the collar bearing. When the equation is integrated over the full bearing area, the applied moment needed to overcome friction and begin rotation can be determined.

Friction Torque in Collar Bearings

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key terms and concepts

Learn how collar bearing contact area, pressure, and friction work together to set the torque needed to start shaft rotation in mechanical systems.

Friction Torque in Collar Bearings | JoVE K12

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Friction Torque in Collar Bearings

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