Bearings – Rotary bearing – Antifriction bearing
Reexamination Certificate
1998-11-30
2001-09-18
Footland, Lenard A. (Department: 3682)
Bearings
Rotary bearing
Antifriction bearing
Reexamination Certificate
active
06290397
ABSTRACT:
BACKGROUND OF THE INVENTION
This application relates to the art of bearings and, more particularly, to bearing lubrication. The invention is particularly applicable to a cartridge bearing and will be described with specific reference thereto. However, it will be appreciated that the invention has broader aspects and can be used in any environment where metered lubricant flow is desired across an interface passage between two joined surfaces that do not move relative to one another.
Bearing cartridges may have a lubricant reservoir from which lubricant is metered at a very slow controlled rate to maintain a lubricant film on the bearing rolling elements and raceways. In one arrangement, the passages through which oil is metered are formed at interfaces between overlapping cylindrical surfaces of reservoir housing members that are secured together within an interference fit. Many different arrangements have been attempted for configuring the surfaces at the interface to insure a desired lubricant flow rate. If the flow rate is too slow or the passages become clogged, the bearing may overheat and fail. If the flow rate is too fast, the lubricant will be exhausted and the bearing may fail before the expiration of its intended design life. Excessive lubricant also is undesirable because it increases torque requirements on the bearing to overcome churning losses. By way of example, the surfaces at the interface have been roughened and etched to provide capillary-like passages for the flow of lubricant. However, such arrangements are difficult to reproduce accurately in mass production and the reject rate is high when lubricators are tested to insure that they meet the design flow rate before assembly into a finished bearing.
It would be desirable to have such a bearing lubricator with an interface passage that is configured to provide accurate and reliable flow of lubricant from the reservoir to the rolling elements and raceways, and that can be accurately reproduced in mass production with minimal rejects.
SUMMARY OF THE INVENTION
A bearing of the type described having a lubricant reservoir with an ooze flow interface passage between overlapping cylindrical smooth surfaces that are sealed together with an interference fit. One interface surface has at least one precision turned generally helical shallow groove through which lubricant flows at a mathematically determined metered flow rate.
In a preferred arrangement, an inner cylindrical surface on an outer lubricant reservoir housing member is precision machined smooth by grinding. An outer cylindrical surface on an inner lubricant reservoir housing member is precision turned smooth by hard turning or diamond turning.
In a preferred arrangement, the helical groove is precision turned by hard turning. However, it will be recognized that the groove might be machined by procedures other than hard turning with the use of a cutting tool that is tipped with a very hard material such as diamond, ceramic or cubic boron nitride.
The improved ooze flow interface passage of the present application is provided in a lubricant reservoir for a cartridge bearing having inner and outer races with rolling elements positioned in raceways between the races. The lubricant reservoir is positioned within the outer race between a pair of inner races, and may be mounted for rotation with the inner or outer races.
The reservoir has inner and outer reservoir housing members with overlapping cylindrical surface portions that are joined together with a leak tight sealed interference fit and include lubricant ooze flow interface passages located adjacent the rolling elements and raceways. During rotation of the reservoir, centrifugal force acting on the lubricant in the reservoir causes same to flow through the interface passages between the inner and outer lubricant reservoir housing members onto the rolling elements and raceways. In accordance with the present application, the interface passages are defined by at least one generally helical shallow groove that is precision turned in one of the overlapping surface portions.
It is a principal object of the present invention to provide an improved lubricant ooze flow interface passage between a pair of surfaces that are joined together with an interference fit.
It is another object of the invention to provide an improved bearing having a lubricant ooze flow interface passage that provides accurate and reliable metered flow of lubricant.
It is a further object of the invention to provide a lubricant ooze flow interface passage that can be mass produced with minimal rejects while providing a predictable and reliable lubricant flow rate.
REFERENCES:
patent: 2992659 (1961-07-01), Thomas
patent: 3730599 (1973-05-01), Fingerle
patent: 3804476 (1974-04-01), Nakamura et al.
patent: 4241959 (1980-12-01), Frister
patent: 4576489 (1986-03-01), Bentele et al.
patent: 4609293 (1986-09-01), Bayer et al.
patent: 4797011 (1989-01-01), Saeki et al.
patent: 4942944 (1990-07-01), Frey et al.
patent: 5066145 (1991-11-01), Sibley et al.
patent: 5320433 (1994-06-01), Kimata et al.
patent: 5489190 (1996-02-01), Sullivan
patent: 5570958 (1996-11-01), Tsukada
patent: 5694811 (1997-12-01), Tsukada
patent: 562908 (1944-07-01), None
Kingsbury, E., “Large Bearing Operation Without Retainer,” ASLE Lubrication Engineering, vol. 35, 9, 517-520, Oct. 24-26, 1978.
Kingsbury, E., “Parched Elastohydrodynamic Lubrication,” Journal of Tribology, vol. 107, 229-233, Apr. 1985.
Singer, Herbert B. and Gelotte, Erik, “Design of a High-Speed Reliable Ball Bearing,” The Charles Stark Draper Laboratory, Inc., 1-6, May 1994.
Kingsbury, E., “Reliable, Economical Bearing Cartridge For Space Application,” SBIR No. 04.04-2374, The Bearing Consultants, LLP, 1-19, Jul. 1996.
Francis, H. A., “The Design of Oozing Flow Lubricators For Retainerless Ball Bearings,” The Charles Stark Draper Laboratory, Inc., 1-45, Oct. 1978-Jun. 1981.
Merriman, Terry L. and Kannel, Jerrold W., “Bearings in Space,” Battelle, 1-16, Sep. 1997.
Footland Lenard A.
Jones Day Reavis & Pogue
The Timken Company
LandOfFree
Ooze flow bearing does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ooze flow bearing, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ooze flow bearing will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2485314