Tribology of hard bearing coatings
- North Carolina State Univ., Raleigh, NC (United States)
The performance of a linear sliding contact bearing is dictated by a frictional effect called stiction. Stiction exists when the static coefficient of friction is substantially higher than the dynamic coefficient. Stiction can cause chatter or jerky motion when attempting to move a slide at low speed. The force required to overcome static friction will cause deflection in the structure of the machine. If the dynamic coefficient is less than the static coefficient, when the slide breaks loose the friction force is suddenly reduced and there is an excess force on the slide and it is accelerated by this unbalanced force. As the slide moves relative to the rest of the structure the force due to the deflection of the structure is relieved. The inertia of the slide will carry it beyond the equilibrium point until the force on the slide is less than that required to overcome dynamic friction and the slide will stop. This process repeats. At high speeds, chatter does not occur because the velocity due to the suddenly unbalanced force at breakaway is small compared to the overall velocity so that the slide never comes to rest. For friction materials with a dynamic coefficient that is not less than static, stiction induced chatter does not occur because there is no excess force when the slide breaks away.
- OSTI ID:
- 535588
- Report Number(s):
- CONF-961111--
- Country of Publication:
- United States
- Language:
- English
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