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

Os rolamentos de colar são um tipo de rolamento usado em máquinas para suportar cargas axiais em eixos rotativos, podendo ter colares simples ou múltiplos.
Considere um único rolamento de colar sujeito a uma carga axial. A área entre o raio externo e interno do colar é a área total de contato do rolamento.
Assumindo um suporte uniforme para o rolamento, a pressão normal uniforme pode ser expressa como a razão de força sobre a área do rolamento.
Considere um elemento de área infinitesimal no rolamento. A força que atua na área diferencial pode ser expressa como um produto do coeficiente de atrito, pressão e área diferencial.
O momento necessário para causar rotação iminente do eixo é determinado a partir da equação de equilíbrio do momento em torno do eixo de rotação.
Em seguida, a integração é usada para determinar o momento aplicado necessário para superar todas as forças de atrito.
Finalmente, substituindo os valores de força diferencial e área diferencial e integrando a equação sobre a área total de apoio, o momento do eixo pode ser estimado.

<ol>
	<li>Hibbeler, R.C. (2016). Engenharia Mecânica \u2012 Estática e Dinâmica. Hoboken, Nova Jersey: Pearson Prentice Hall. Pág. 447-448.</li>
</ol>

rolamentos de colarinho

Os rolamentos de colarinho são essenciais em várias máquinas projetadas para suportar cargas axiais em eixos rotativos. Dependendo da aplicação específica e dos requisitos, eles podem ser encontrados com um ou vários colarinhos.

<img alt="Figure 1" src="/files/ftp_upload/14325/14325_Figure_1v3.svg" style="text-align: center; height: 300px;" />

Considere um rolamento de colarinho único sujeito a uma carga axial. A área total de contato do rolamento é a região entre o raio externo e o raio interno do colarinho. Quando o rolamento é assumido como fornecedor de suporte uniforme, a pressão normal uniforme pode ser calculada dividindo-se a força aplicada no colarinho pela área total de contato do rolamento. Esse valor representa a distribuição média de pressão em toda a superfície do rolamento.

Para analisar ainda mais as forças que atuam no rolamento de colarinho, considere um elemento de área infinitesimal pequeno na superfície do rolamento. A força que atua nesse elemento de área infinitesimal é um produto do coeficiente de atrito, da pressão e da área diferencial. Compreender a relação entre essas variáveis é crucial para calcular o momento necessário para o eixo girar.

A iminente rotação do eixo é determinada pela análise da equação do momento de equilíbrio em torno do eixo de rotação. Essa equação considera todas as forças e momentos atuando no eixo, incluindo as forças de atrito geradas pelo rolamento de colarinho.

<img alt="Equation 1" src="/files/ftp_upload/14325/14325_Equation_1v2.svg" style="text-align: center; height: 39px;" />

Ao integrar a equação, o momento aplicado necessário para superar todas essas forças de atrito pode ser determinado, o que inicia a rotação do eixo. Por fim, para estimar o momento do eixo, substitua os valores de força diferencial e área na equação integrada.

<img alt="Equation 2" src="/files/ftp_upload/14325/14325_Equation_2v2.svg" style="text-align: center; height: 55px;" />

Integrando essa equação em toda a área total do rolamento, obtém-se uma compreensão abrangente das forças e momentos atuando no rolamento de colarinho e do momento necessário para o eixo girar.

<img alt="Equation 3" src="/files/ftp_upload/14325/14325_Equation_3v2.svg" style="text-align: center; height: 39px;" />

Rolamentos de colarinho

Os rolamentos de colar são essenciais em várias máquinas projetadas para suportar cargas axiais em eixos rotativos. Dependendo da aplicação específica e ...

Education

JoVE Core

Mechanical Engineering

Engenharia Mecânica

Unit 1

Unidade 1

Friction

Atrito

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

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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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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mechanical engineering

Friction Torque in Collar Bearings

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