Abstract:
A bearing housing comprising an annulus having an aft side and a forward side, a barrier extending from the aft side to the forward side to form a first and second zone, a first opening in the first zone extending through the forward side, and a second opening in the second zone extending through the forward side at least a portion of the first opening being at a level lower than a lowermost level of the second opening.

Description:
U.S. GOVERNMENT RIGHTS 
   The Government may have rights in this invention, pursuant to Contract No. N00019-02-C-3003, awarded by the United States Navy. 

   BACKGROUND OF THE INVENTION 
   (1) Field of the Invention 
   The present invention relates to a bearing housing, and method for so producing, which allows for both the drainage and the pooling of oil. 
   (2) Description of the Related Art 
   Typically, bearing housings are designed to perform numerous functions including protecting the bearing compartment from the outside environment, supporting a bearing, and providing a means of draining oil away from the bearings and seals to a scavenge pick up. However, it is often times preferable to retain an amount of oil in a reserve reservoir for use in the instance that supply of oil to the bearing housing is momentarily interrupted. The idea of retaining oil, or maintaining an oil reservoir, is therefore in conflict with the fundamental function of draining oil back to scavenge lines. Without drain back capability whereby oil is drained back to the scavenge lines, the bearing housing compartment can be flooded with oil resulting in operational problems. 
   There is therefore a need for a bearing housing which balances the need for maintaining an oil reservoir with the conflicting need of draining oil out of the bearing housing and into scavenge lines. Specifically, there is a need for a bearing housing design which balances these two conflicting requirements. 
   SUMMARY OF THE INVENTION 
   Accordingly, it is an object of the present invention to provide a bearing housing, and method for so producing, which allows for both the drainage and the pooling of oil. 
   In accordance with the present invention, a bearing housing comprises an annulus having an aft side and a forward side, a barrier extending from the aft side to the forward side to form a first and second zone, a first opening in the first zone extending through the forward side, and a second opening in the second zone extending through the forward side at least a portion of the first opening being at a level lower than a lowermost level of the second opening. 
   In further accordance with the present invention, a method of draining and pooling oil in an annulus comprises the steps of forming an annulus from an aft side and a forward side, providing a barrier extending from the aft side to the forward side at a height to form a first and second zone, forming a first opening extending through the forward side at least a portion of the first opening located below a fill level, forming a second opening extending through the forward side and located above the fill level, and evacuating oil through the first opening from the first zone and pooling oil in the second zone. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  perspective line rendering of the bearing housing of the present invention showing the orientation of the cross section forming  FIG. 4  and  FIG. 2 . 
       FIG. 2A  cross section illustration the bearing housing of the present invention showing the barrier. 
       FIG. 3A  perspective line rendering of the bearing housing of the present invention showing the placement of the openings, the barrier, and the water line. 
       FIG. 4A  cross section of the bearing housing of the present invention. 
   

   DETAILED DESCRIPTION 
   It is therefore a teaching of the present invention to provide a bearing housing which makes use of a first and a second opening extending into the bearing housing on either side of a barrier positioned so as to simultaneously drain excess oil and retain a sufficient reserve of oil. As will be described more fully below, the aforementioned openings are able to maintain two separate and different levels of oil resulting from the fact that they extend into two separate zones formed on either side of a barrier. The barrier is created during the casting of the bearing housing. The air pipe serves as an exit for high pressure air supplied to the housing bearing so as to affect a tight seal and provide egress for any oil that may overcome the seal. The present invention makes use of the barrier to both drain oil on one side of the barrier to the first opening and reserve oil on the other side of the barrier. 
   In general, oil is pumped into a bearing compartment through oil supply tubes. It is then generally dived into desirable proportions through manifolds, nozzles, or internal passage ways. Some of this oil may be jetted at a target through a nozzle. Often this target is a, bearing, gear, seal, additional passageway, or other structures. In this bearing compartment some oil is directed at a bearing and seal. This bearing and seal is housed by the bearing housing  10 . Of the oil that is directed at the bearing, roughly equal portions of that oil pass through the bearing in the forward and aft directions traveling radially outwards. The oil that has traveled aft of the bearing and radially outwards is collected by the bearing housing  10 . Oil directed towards the seal, which is aft of the bearing, travels radially outwards, is also collected by the housing  10 . The aggregate of the oil that has traveled aft of the bearing is collected by the bearing housing  10  and drained or collected, according to the principle of the present invention. 
   With reference to  FIGS. 1 and 3 , there is illustrated the bearing housing  10  of the present invention. Bearing housing  10  is radially disposed about a centerline  15 . Air is pumped into the bearing housing  10  through entrance air pipe  29  and the air exits the bearing housing towards the bottom of the bearing housing  10  through exit air pipe  27 . With reference to  FIG. 4 , there is illustrated in detail a partial cross-section of bearing housing  10  as taken along line  4 — 4  of  FIG. 1 . Bearing housing  10  is comprised of an aft side  21  and a forward side  23  forming annulus  22 . In operation, the bearing housing  10  is situated as illustrated in  FIG. 3  such that oil within the bearing housing  10  will collect under force of gravity within the annulus  22  at the bottom of bearing housing  10  in the vicinity of exit air pipe  27  located towards the bottom of bearing housing  10 . Note that section  4 — 4  is taken at bottom dead center (BDC) of the bearing housing  10  during operation. Note further, that exit air pipe  27  is slightly displaced from bottom dead center (BDC). 
   With reference to  FIG. 2 , there is illustrated the barrier formed by the fabrication of exit air pipe  27 .  FIG. 2  is a perspective rendering showing a cross-section of bearing housing  10  taken through the centerline of exit air pipe  27  along line  2 — 2  of  FIG. 1 . As can be seen, a barrier  25  is formed from air pipe  27  and a blocking element  28  extending from beneath exit air pipe  27  downwards and outwards and into contact with both aft side  21  and forward side  23 . As a result, barrier  25  prevents the free movement of oil collecting at the bottom of bearing housing  10  from side-to-side. Because barrier  25  prevents the free movement of oil from one side of barrier  25  to the other side of barrier  25  within annulus  22 , it is possible to fabricate draining holes through forward side  23  from annulus  22  such that oil drains from each side of barrier  25  at a different rate. 
   With reference to  FIG. 3 , there is illustrated in detail the position and function of first opening  11  and second opening  13  used to achieve a differential accumulation/drainage of oil having pooled at the bottom of annulus  22 . Barrier  25  effectively separates annulus  22  into a first side  53  and a second side  55 . Fill level  51  defines the uppermost desirable level of oil such that the amount of oil retained on second side  55  bounded by barrier  25 , aft side  21 , and forward side  23  is of an amount sufficient to meet the retained oil requirements of bearing housing  10 . Second opening  13  is preferably fabricated through forward side  23  into annulus  22  such that the lowest part of second opening  13  is at the same approximate level as water level  51 . Fill level  51  is preferably just below the highest point of barrier  25 . Conversely, first opening  11  is fabricated through forward side  23  and extending into annulus  22  on first side  53  in as close a proximity as is practicable to barrier  25 . The size of the first opening  11  is selected to provide for oil drainage in accordance with the specified oil drainage requirement of the bearing housing  10 . In a preferred embodiment, openings  11 ,  13  form slots circumferentially disposed about forward side  23 . 
   In operation, oil tends to pool at the bottom of bearing housing  10  and annulus  22  on both sides of barrier  25  at approximately the same rate. As first opening  11  is located quite close to BDC and in proximity to the barrier  25 , oil which begins to collect on first side  53  tends to evacuate the bearing housing  10  through first opening  11 . Conversely, as oil begins to collect on second side  55  of annulus  22 , the oil so collecting tends to form a reserve whose level steadily increases until the level of the oil in reserve reaches fill level  51 . At the point at which the oil level reaches fill level  51 , any addition of oil to second side  55  results in the evacuation of oil through second opening  13 . Thus, there is continually evacuated, or scavenged, oil from the first side  53  of bearing housing  10 , while simultaneously there is pooled in reserve a desired volume of oil extending up to water level  51 . In the event that oil should collect so quickly such that the oil level in both first side  53  and second side  55  rises above the top of barrier  25 , both the first opening  11  and second opening  13  will act in unison to evacuate excess oil. 
   It is apparent that there has been provided in accordance with the present invention a bearing housing, and method for so producing, which allows for both the drainage and the pooling of oil which fully satisfies the objects, means, and advantages set forth previously herein. While the present invention has been described in the context of specific embodiments thereof, other alternatives, modifications, and variations will become apparent to those skilled in the art having read the foregoing description. Accordingly, it is intended to embrace those alternatives, modifications, and variations as fall within the broad scope of the appended claims.