1. Field of the Invention
This invention relates to systems used in rolling mill oil film bearings to remove laminar flows of oil exiting tangentially from between the rotating sleeves and the stationary bushings surrounding the sleeves, and is concerned in particular with a neck seal for use in such systems.
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.
In an improved system described in a copending application, the kinetic energy of rotating bearing components is employed 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.
The present invention is directed to an improved neck seal adapted to be mounted on and to rotate with the roll neck. The neck seal coacts with other bearing components to define an annular chamber arranged to receive the laminar flow of oil exiting from between the sleeve and bushing. The annular chamber has a tangential outlet, and the oil is rotatively driven around the chamber and out through the outlet by impellers carried by the neck seal.
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
Axially spaced flanges 32a, 32b project radially outwardly from opposite ends of a cylindrical surface 31 on the neck seal body 25. The flanges 32a, 32b sealingly contact shoulders 34 on the seal end plate. An annular flinger 36 on the neck seal sealing contacts a circular shoulder 38 on extension 30. The flinger projects from the seal body at an obtuse angle with respect to an outboard end face 25′ of the seal body, and at an acute angle with respect to flange 32b. Confinement surfaces provided by the flinger 36, extension 30 and chock 20 cooperate with the sleeve 12 and hushing 18 to define an annular inboard chamber 40 isolated from a sump 28 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 40 from the seal body 25 at the juncture of the flinger 36 and the end face 25′. 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 40 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. In the cross sectional area of the annular chamber 40 spanned by the impellers 42, the oil is rotatively propelled at the velocity of the sleeve, thus serving to efficiently pump the oil around chamber 40 and out through the outlet 44.
It thus will be seen that the impellers 42 serve to harness the rotating kinetic energy of the neck seal 24 to exert a pumping action which forcibly ejects oil from the annular chamber 40. 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.