Self-lubricating journal bearing

A self-lubricating journal bearing includes an arcuate bearing plate having a concave bearing surface. A plurality of lubricant plugs are positioned in apertures in the surface of said plate and are adapted to engage a rotating journal supported on said bearing surface for providing lubrication between said journal and said bearing plate. The lubricant plugs comprise an oil and polymer lubricating composition. The apertures and plugs are arranged to provide continuous lubrication over substantially the entire bearing surface as the journal rotates thereon, and coolant grooves are cut into the bearing surface of said bearing plate in a generally X-shaped pattern for channeling liquid coolant between the journal and the bearing plate.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to journal bearings and, more particularly, 
to self-lubricating journal bearings incorporating lubricant plugs and 
coolant channels. 
2. Description of the Prior Art 
Journal bearings are conventionally formed of fiber or babbit materials. 
Machines such as those used to hot roll large billets in steel mills 
utilizing rolls and shafts weighing many tons and are subjected to 
additional bearing forces of many more tons from the reaction of the 
rolling process. In many of these machines, the rolls are supported on 
sleeve or journal bearings which may be made from bronze or babbit metals 
or from composite structures such as fiberglass mats impregnated with 
epoxy resin. 
In steel mill rolling applications, the roll bearings cannot be lubricated 
by the well established principles of lubrication engineering because of 
the high temperatures of the billets of steel which are in close proximity 
to the bearings. Current practice is to spray the bearing housings with 
cooling water and to flood the bearings with water for the purposes of 
cooling and generating a hydrodynamic lubricating film. The bearings wear 
rapidly and substantial time and cost is involved in the necessary 
periodic bearing changes. 
OBJECTS OF THE INVENTION 
It is the principal object of the present invention to provide an improved 
bearing for supporting a journal or shaft under high temperature and load 
conditions such as are encountered in a rolling mill. 
Another object of the present invention is to provide a journal bearing 
which is self-lubricating under high load and temperature conditions. 
A further object of the present invention is to provide a journal bearing 
of the foregoing type which is suitable for use with water cooling. 
Other objects and advantages of the present invention will become apparent 
as the following description proceeds, taken in conjunction with the 
accompanying drawings. 
SUMMARY OF THE INVENTION 
In accordance with the foregoing objects and as shown in the drawings, the 
present invention comprises an arcuate bearing plate having a concave 
bearing surface adapted to support a rotating journal. The bearing plate 
is mounted in a pillow block. A similar cap structure can be provided. For 
providing lubrication between the bearing plate and a rotating journal 
supported thereon, a plurality of lubricant bearing plugs are inserted 
into apertures in the bearing plate and open into the bearing surface 
thereof for lubricating engagement with the journal. Coolant channels are 
cut into the bearing surface of the bearing plate for conducting coolant 
such as water when the bearing structure is to be utilized in high 
temperature applications such as supporting rolls in a rail mill. The 
lubricant bearing material may be a mixture of a hydrocarbon oil and 
polyethylene or other suitable oil and polymeric material lubricating 
composition.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
The present invention, as illustrated in the drawings, comprises a 
stationary journal bearing structure 10 adapted for rotatably supporting a 
journal (not shown) and for lubricating and cooling the interface between 
the rotating journal and the stationary bearing. The bearing structure 10 
comprises a pillow block 11 having a concave surface 12 mounting an 
arcuate bearing plate 14. The bearing plate 14 is held in the pillow block 
11 by clamp blocks 15 secured to the pillow block 11 by bolts 16. In use, 
the journal is rotatably supported on the upper concave surface 18 of the 
bearing plate 14. When the bearing plate has been worn out by the rotation 
of the journal, it can be readily replaced in the pillow block 11 by 
unbolting the bolts 16 and removing the clamps 15. After a substitute 
bearing plate has been inserted into the pillow block, the clamps 15 are 
again mounted and bolted in place. 
In order to provide for lubrication between the journal and the bearing 
plate 14, plugs 19 of lubricant containing material are mounted in the 
bearing plate 14 and project into the bearing surface 18 thereof. The 
lubricant plugs are formed of a composition of lubricating oil and a high 
molecular weight polymer. Such a lubricant material may be formed, for 
example, by mixing polymeric materials such as polyethylene, 
polypropylene, polyurethanes, polyesters and polyamides, with an 
appropriate lubricating oil such as a hydrocarbon or petroleum oil, 
silicone oils or other liquid lubricating materials. Illustrative oil and 
polymeric material lubricating compositions are disclosed, for example, in 
U.S. Pat. No. 3,541,011, issued Nov. 17, 1970 to W. J. Davis et al., and 
U.S. Pat. No. 3,547,819, issued Dec. 15, 1970 to W. J. Davis et al. 
In operation, the polymeric lubricating medium wicks lubricating oil to the 
journal supported on the bearing plate. As the shaft rotates under load, 
oil is drawn from the plugs of polymeric lubricating medium in the bearing 
by capillary action. This oil then forms a lubricating film under pressure 
between the journal and the supporting surface of the bearing plate. 
Where the bearing structure is to be utilized in an environment in which 
the journal is subjected to extreme heat, it is desirable that provision 
be made for cooling the bearing structure. One conventional procedure is 
to spray the bearing structure with water. In order to provide for the 
flow of coolant water through the bearing, channels 20 are desirably cut 
in the bearing surface 18 of the bearing plate 14. In the embodiment shown 
in the drawings, the coolant channels 20 extend diagonally across the 
surface of the bearing plate, thereby forming an X-shaped water channel. 
The lubricant plugs 19 are received in holes or apertures 21 cut into the 
surface 18 of the bearing plate 14. In order to insure a continuous film 
of lubrication over the major portion of the bearing surface, the 
alignment of the holes 21 is staggered as shown in FIG. 3 so that the 
holes and thus the lubricant plugs overlap in the direction of rotation, 
indicated by the arrow 22 shown on FIG. 3. The plugs 19 are tapered as 
shown in FIG. 4 to a frusto-conical form to provide for a press fit into 
the holes 21. In order to provide an escape for air trapped in the holes 
behind the plugs, the plugs may be provided with an axially extending 
groove 24. 
During operation of the journal bearing, lubricant weeps from the plugs and 
provides a lubricating film between the journal and the bearing surface. 
In order to maintain the desired lubricating characteristics of the 
bearing plate, the plugs can be periodically replaced. The use of the 
lubricant plugs obviates the necessity for external lubrication of the 
bearing structure. 
The bearing structure may also include a corresponding cap bearing (not 
shown) including a similar bearing plate mounted on top of the journal in 
the conventional manner. 
While a certain illustrative embodiment of the present invention has been 
shown in the drawings described above in considerable detail, it should be 
understood that there is no intention to limit the invention to the 
specific form disclosed. On the contrary, the intention is to cover all 
modifications, alternative constructions, equivalents and uses falling 
within the spirit and scope of the invention as expressed in the appended 
claims.