Patent Application
20110274380
1. Field of the Invention
This invention relates to a system for use in a rolling mill oil film bearing to remove a laminar flow of oil exiting tangentially from between a rotating sleeve and a stationary bushing surrounding the sleeve.
2. Description of the Prior Art
In a typical rolling mill oil film bearing, a sleeve surrounds and is rotatable with a roll neck. The sleeve is journalled for rotation within a fixed bushing contained in a chock. The sleeve and bushing are dimensioned to define a gap therebetween. During operation, oil is introduced continuously into the gap where it is rotatably urged into a hydrodynamically maintained film between the sleeve and bushing at the load zone of the bearing. Laminar flows of oil exit tangentially from each end of the bearing into sumps from which the oil is removed by gravity for filtering and cooling before being recirculated back to the bearings.
A drawback of this arrangement is that large diameter drain lines are required to accommodate the gravity flow of oil exiting from the bearings. These drain lines occupy an inordinate amount of exterior space and thus contribute disadvantageously to the overall size of the bearing. Care must also be taken to insure that the drain lines are properly installed with pitches designed to prevent oil from backing up into and flooding the bearing sumps.
Broadly stated, the objective of the present invention is to employ the kinetic energy of rotating bearing components to pump oil out of the bearings. Because the oil is forcibly expelled, smaller drain lines may be employed to handle the exiting oil flow, without the need to maintain the drain pitches required to accommodate gravity flow.
These and other features and advantages of the present invention will now be described in further detail with reference to the accompanying drawings, wherein:
With reference initially to
Seal assemblies 22a, 22b are located respectively at the inboard and outboard ends of the bearing. With additional reference to
In conventional bearings, the laminar flow of oil escaping tangentially from between the sleeve and bushing is received in a sump 28a, from which it is drained by gravity. As can be seen from
With the present invention, however, a circular extension 30 spans a gap between the seal end plate 26 and the chock 20. Flanges 32 on the neck seal sealingly contact shoulders 34 on the seal end plate, and a flinger 36 on the neck seal sealing contacts a circular shoulder 38 on extension 30. Confinement surfaces provided by the flinger 36, extension 30 and chock 20 cooperate with the sleeve 12 and bushing 18 to define an annular inboard chamber 40a isolated from the sump 28a and arranged to receive the laminar flow of oil exiting tangentially from the gap G between the sleeve and bushing. Impellers 42 project into the chamber 40a. As can be best seen by additional reference to
As shown in
The outlet 44 is sized with respect to the volume of oil being received in the annular chamber 40a such that during steady state operation, that chamber remains filled with oil. As noted previously, both the seal 24 and sleeve 12 are mounted on and rotate with the roll neck 14. Thus, the impellers 42 carried by the seal 24 rotate with and at the velocity of the sleeve. As shown diagrammatically in
With reference to
Although not illustrated, it is to be understood that extension 48 includes an onboard outlet similar to the inboard outlet shown at 44 in
It thus will be seen that the impellers 42 serve to harness the rotating kinetic energy of selected bearing components (for example, the neck seal 24 at the inboard end and the sleeve 18 at the outboard end) to exert a pumping action which forcibly ejects oil from the annular chambers 40a, 40b. As noted above, by forcibly ejecting oil rather than relying on gravity flow, smaller diameter drain lines may be employed and strategically positioned without regard to the maintenance of gravity pitches.
