According to the rule of thumb in journal bearing design, what is the recommended clearance ratio for bearings?

In journal bearing design, the clearance ratio is a critical parameter that influences the bearing's performance, including its load-carrying capacity, lubrication, and operating efficiency. The correct choice reflects the commonly accepted rule of thumb for clearance in journal bearings, which dictates that the clearance should ideally be a small fraction of the journal diameter to ensure adequate lubrication and minimize friction.

A clearance ratio of 0.0010 is appropriate for most applications, particularly in conditions where precise alignment and low friction are crucial. This ratio allows for a thin film of lubricant to form between the bearing and the journal, thereby reducing wear and thermal stresses.

Maintaining this clearance ratio allows for effective oil retention and consistent hydrodynamic lubrication, promoting longevity and reliability in mechanical systems that utilize journal bearings. It strikes a balance between having enough clearance to allow for thermal expansion and contamination while ensuring that the lubricant can maintain a film to prevent metal-to-metal contact.