Abstract:
A gravity fed bearing lubrication system for distributing lubricant to powertrain components in a motor vehicle, including a lubricant supply, a bearing, and a bearing housing. A three-dimensional cast-in portion of the bearing housing controls the communication of lubricant to the bearing.

Description:
FIELD 
     The present invention relates to systems and methods for supporting a bearing in a housing and providing a mechanism to ensure the bearing is lubricated. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. 
     A typical gravity-feed bearing lubrication system for lubricating a bearing in an automobile includes a bearing housing, lubrication ports and a lubricant. The bearing is, typically, pressed into the bearing housing, and a supply of lubricant is provided to the bearing by a lubricant supply port or aperture formed in the bearing housing. The lubricant is carried from the lubricant supply aperture into the bearing housing, through the bearing, and to a lubricant departure aperture by gravity. 
     The bearing is commonly constructed with an inner bearing race, an outer bearing race, a bearing cage disposed between the inner race and outer race, and a plurality of bearing members that are also disposed between the inner race, the outer race, and the bearing cage. The inner bearing race rotationally supports a shaft or rotating component with which the bearing is axially aligned. The outer bearing race is typically anchored to the bearing housing such that the inner race and outer race may move relative to one another, but remain fixed to the shaft or rotating component and the bearing housing respectively. 
     Under normal operating conditions, a typical gravity-feed bearing lubrication system may only require nominal lubricant flow to the bearing and bearing housing for both lubrication and heat transfer purposes. However, under severe conditions, such as under extreme acceleration, or on a steep grade driving, the bearing and bearing housing require consistent lubricant flow to maintain proper friction and temperature characteristics. If an excessive supply of lubricant is directed to the bearing, that lubricant can become entrained in the bearing and lead to frictional losses and operational inefficiency. If a paucity of lubricant is provided to the bearing, the lack of lubricant also leads to undesirable frictional losses and wear on the bearing. 
     While conventional gravity-feed bearing lubrication systems are effective, there is room for improved lubrication supply systems that ensure the proper amount of lubricant is supplied to the bearing under extreme operating conditions. Especially desirable, would be a lubrication system that performs under extreme operating conditions and does not cause a loss in operating efficiency. 
     SUMMARY 
     In an embodiment of the present invention, a system for lubricating a bearing is provided. The bearing includes an inner race, an outer race and a plurality of bearing members disposed there between. The bearing is disposed in a housing. The system has a bearing pocket formed in the housing for supporting the bearing. The bearing pocket is annular and has an open end and a partially closed end and a cylindrical portion disposed between the open end and the partially closed end. The cylindrical portion has a first end, a second end, and a surface and the bearing pocket is configured to receive the bearing. The partially closed end is partially closed by an annular flange extending radially inwardly from the cylindrical portion of the bearing pocket and the second end of the cylindrical portion has an outwardly extending radial wall formed therein. There is a raised flange positioned along a portion of the annular flange. The raised flange extends radially inwardly from the annular flange. There is also a weir formed in the cylindrical portion of the bearing pocket and extending axially from within the annular flange and through the radial wall to the open end, and, the outer race of the bearing is positioned adjacent the radial wall and inside the bearing pocket. A lubricating fluid is trapped by the raised flange in the bearing pocket and through the bearing until the fluid rises to a level of the weir. 
     In another embodiment of the present invention, the weir is positioned at a first end of the raised flange. 
     In yet another embodiment of the present invention, the weir is a u-shaped trough for capturing lubrication fluid and carrying the fluid from a first side of the bearing underneath the bearing to a second side of the bearing. 
     In still another embodiment of the present invention, a lubrication port for providing lubricating fluid to the bearing is positioned at a second end of the raised flange. 
     In a further embodiment of the present invention, the raised flange portion has a height that allows the lubricant to rise to a level where a bottom bearing member is at least half-way submerged in the lubricant. 
     In yet a further embodiment of the present invention, the raised flange portion has a ridge that extends from the annular flange to the radial wall. 
     In still a further embodiment of the present invention, the ridge of the raised flange portion decreases in height relative to the cylindrical portion from the annular flange to the radial wall. 
     In another embodiment of the present invention, the raised flange portion decreases in height relative to the cylindrical portion from the ridge to the weir. 
     In yet another embodiment of the present invention, the raised flange portion decreases in height relative to the cylindrical portion from the ridge to the lubrication port. 
     In still another embodiment of the present invention, the raised flange portion is configured to form a cup shape to capture lubrication fluid between the raised flange portion and the bearing to restrict fluid flow to the weir. 
     In a further embodiment of the present invention, a system for lubricating a bearing having an inner race and an outer race and a plurality of bearing balls disposed there between is provided. The bearing is disposed in a housing. A bearing pocket is formed in the housing for supporting the bearing. The bearing pocket is annular and has an open end and partially closed end and a cylindrical portion disposed between the open end and the partially closed end. The cylindrical portion has a first end and a second end and a surface there between and the bearing pocket is configured to receive the bearing. The partially closed end is partially closed by an annular flange extending radially inwardly from the surface of the cylindrical portion of the bearing pocket and the second end of the cylindrical portion has an outwardly extending radial wall formed therein. There is a diverter positioned along a portion of the annular flange. The diverter extends radially inwardly from the annular flange, and the diverter extends axially from the partially closed end. There is a weir formed in the surface of the cylindrical portion of the bearing pocket and extending axially from within the annular flange and through the radial wall to the open end. There is also a lubrication port formed in the housing. The weir is positioned at a first end of the diverter, and the lubrication port is positioned at a second end of the diverter. The outer race of the ball bearing is positioned adjacent the radial wall and inside the bearing pocket and a lubricating fluid is trapped by the diverter in the bearing pocket and through the bearing until the fluid rises to a level of the weir. 
     In yet a further embodiment of the present invention, the weir is a u-shaped trough for capturing lubrication fluid and carrying the fluid from a first side of the bearing underneath the bearing to a second side of the bearing. 
     In still a further embodiment of the present invention, the diverter has a height that allows the lubricant to rise to a level where a bottom bearing ball is at least half-way submerged in the lubricant. 
     In another embodiment of the present invention, the diverter has a ridge that extends from the annular flange to the radial wall. 
     In still another embodiment of the present invention, the ridge of the diverter decreases in height relative to the surface of the cylindrical portion from the annular flange to the radial wall. 
     In yet another embodiment of the present invention, the diverter decreases in height relative to the surface of the cylindrical portion from the ridge to the weir. 
     In a further embodiment of the present invention, the diverter decreases in height relative to the surface of the cylindrical portion from the ridge to the lubrication port. 
     In still a further embodiment of the present invention, the diverter is configured to form a cup shape to capture lubrication fluid between the raised flange portion and the ball bearing to restrict fluid flow to the weir. 
     In yet a further embodiment of the present invention, the diverter extends at least partially into the weir. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the views. In the drawings: 
         FIG. 1 a    is an exploded perspective view of a bearing and a bearing lubrication system a vehicle is operating under normal conditions, according to the principles of the present invention; 
         FIG. 1 b    is a partial plan view of a bearing and a bearing lubrication system when the vehicle is operating in extreme conditions, according to the principles of the present invention; 
         FIG. 2  is a partial cross-sectional view of a portion of the bearing and bearing lubrication system of  FIG. 1 a   , according to the principles of the present invention; and 
         FIG. 3  is a cross-sectional view of a portion of the bearing and bearing lubrication system of  FIG. 1 a   , according to the principles of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. Accordingly, a lubrication system and method for a ball bearing is disclosed as an example of one embodiment of the present invention, however, the present invention contemplates that the bearing member may be a ball bearing, a roller bearing, a needle bearing, or any other type of rolling element bearing without departing from the scope or intent of the present disclosure. 
     Referring to  FIG. 1 a   , an exploded perspective view of a system  10  for lubricating a gravity-fed ball bearing  12  is illustrated. To aid in understanding this disclosure, reference lines A, B, and P are provided in  FIG. 1 a   , and reference lines A and B are provided in  FIG. 1 b   . In  FIG. 1 a   , stationary reference line A is a clock-position reference line from 12 o&#39;clock to 6 o&#39;clock, stationary reference line B is a clock-position reference line from 9 o&#39;clock to 3 o&#39;clock, and reference line P denotes the level to which lubricant may rise in a normal operating state of the system. Stationary reference lines A and B are in a separate and fixed reference frame relative to the system  10 . The housing  14  will rotate when the vehicle to which the housing  14  is attached is accelerating or driving on an incline. 
     The system  10  includes a housing  14  for supporting the ball bearing  12 . The ball bearing  12  has an inner race  16  and an outer race  18 , a ball bearing cage  20 , and a plurality of bearing balls  22 . The bearing balls  22  are disposed within the ball bearing cage  20  and between the inner race  16  and the outer race  18 . The ball bearing  12  is configured to rotatably support a component, such as a shaft for free rotation in the housing  14 . More specifically, the outer race  18  is fixed to the housing  14  while the inner race  16  is free to rotate within the housing. A shaft may be fixed to the inner race  16  and is free to rotate with the inner race  16 . 
     The housing  14  of the system  10  for lubricating the bearing  12  includes a bearing pocket  24 , an annular flange  26 , a weir  28 , and a lubricant port  30 . Bearing pocket  24  is configured to support bearing  12  within the housing  14 . The bearing pocket  24  is annular and sized to accept the outer bearing race  18 . The bearing pocket  24  has an open end  32  and a partially closed end  34  with a bearing seat  36  and a cylindrical portion  38  disposed there between. 
     The bearing seat  36  has a cylindrical surface that extends axially from the open end  32  to a bearing seat radial wall  40 . The bearing seat  36  has an axial depth “d” defined by the axial distance between the open end  32  and bearing seat radial wall  40 . The axial depth “d” is approximately equal to an axial width “e” of the outer bearing race  18 . The bearing seat radial wall  40  has a radial height “f” approximately equal to a radial height “g” of the outer bearing race  18 . The outer bearing race  18  of the ball bearing  12  is adjacent to the bearing seat radial wall  40  and inside the bearing seat  36 . The cylindrical portion  38  has a surface  38 A disposed radially inward of the bearing seat  36  and extends axially from the bearing seat radial wall  40  at a second end  38 B of the cylindrical portion  38  to the partially closed end  34  and the annular flange  26  at a first end  38 C of the cylindrical portion  38 . The annular flange  26  has a surface disposed radially inward of the cylindrical portion  38  and defines the partially closed end  34  of the bearing pocket  24 . The annular flange  26  has an axial depth “h” and defines the partially closed end  34 . 
     The housing  14  also includes a diverter or levy contour  42 . The diverter or levy contour  42  is formed or positioned overtop a portion of the annular flange  26 , and extends into a portion of the bearing pocket  24 . Levy contour  42  has an axial depth “i” and a radial height “j”. The levy contour  42  extends axially through the housing  14  from the flange  26  across the bearing pocket  24  to the bearing seat radial wall  40 . Levy contour  42  also extends transversely across a portion of the partially closed end  34  from the lubricant port  30  to the weir  28 . The levy contour  42  axial depth “i”, and a radial height “j” vary along the transverse aspect of the levy contour  42  between the lubricant port  30  and the weir  28 . The levy contour  42  has a maximum axial depth  44  that extends substantially from the annular flange  26  to the bearing seat radial wall  40 . The levy contour  42  maximum axial depth  44  is located approximately halfway between the weir  28  and lubricant port  30 . The levy contour  42  has a maximum radial height  46  that is also located approximately halfway between the weir  28  and the lubricant port  30 . Additionally, between the maximum depth  44  and the maximum height  46  of the levy contour  42 , there is a ridge  48 . The ridge  48  slopes from the partially closed end  34  to the bearing seat radial wall  40 . From the ridge  48 , the levy contour  42  slopes to the surface of the cylindrical portion of the bearing pocket  24 , proximate to the lubricant port  30  on a side of the ridge  48  and proximate to the weir  28  on another side of the ridge. The levy contour  42  obstructs lubricant flow to the weir  28  so that a portion of the lubricant that enters the bearing pocket  24  is directed or diverted to the bearing  12 , instead of exiting the housing  14  through the weir  28  and circumventing the bearing  12 . 
     The weir  28  is a u-shaped trough formed in the bearing housing  14 . The weir  28  extends axially through a portion of the flange and through the bearing pocket  24  to the bearing pocket open end  32 . The weir  28  also has a first axial edge  52 , and a second axial edge  54 . The first edge  52  and second axial edge  54  are spaced by an arc length “k” in the housing  14 . 
     Under normal operating conditions the weir  28  is located at a clock position of approximately 4 o&#39;clock to 5 o&#39;clock relative to stationary reference lines A and B. The weir first edge  52  defines a circumferential arc limit of the weir  28  closest to 6 o&#39;clock, and is separated from the weir second edge  54  which defines another circumferential arc limit of the weir  28  closest to 3 o&#39;clock. Under normal operating conditions, the weir first edge  52  is located at approximately the 5 o&#39;clock position. 
     The lubricant port  30  is in communication with a source of lubricant and is configured to supply lubricant to the bearing pocket  24 . Under normal operating conditions, the lubricant port  30  provides lubricant to the system  10  at approximately the 10 o&#39;clock position. The lubricant then traverses the bearing pocket  24  to the 6 o&#39;clock position where the lubricant forms a pool indicated by reference line “P” in the bearing pocket  24  against the bearing  12 . When the lubricant fluid level rises to the weir first edge  52  at approximately the 5 o&#39;clock position, the lubricant will spill out of the bearing housing  14  through the weir  28 . Thus, weir  28  is in fluid communication with the lubricant on both sides of the bearing  12 . Under normal operating conditions, the lubricant pool level should be at approximately one half of the height of the bottom bearing ball  22 . 
     Turning now to  FIG. 1 b   , the system  10  for lubricating a gravity-fed ball bearing  12  disposed in a housing  14  in an extreme operating condition is illustrated.  FIG. 1 b    includes reference lines A and B from  FIG. 1 a   . In  FIG. 1 b   , the system  10  is rotated relative to the stationary clock reference lines A and B. In  FIG. 1 b   , the weir  28  is located at approximately the 6 o&#39;clock position. Under extreme operating conditions, such as aggressive acceleration or incline-driving, the system  10  may rotate relative to the reference lines A and B, as shown in  FIG. 1 b   . In  FIG. 1 b   , lubricant fluid enters the system  10  via the lubricant port  30  at approximately the 11:30 position, after which lubricant flows to the weir  28  and exits the bearing pocket  24 . Levy contour  42  impedes the flow of lubricant to the weir  28  and causes lubricant fluid to flow into the bearing  12  in a quantity that is substantially similar to the amount of lubricant entrained within the bearing  12  during normal operating conditions as shown in  FIG. 1 a   . More specifically, the levy contour  42  causes the lubricating fluid to pool and rise to a level in the bearing pocket  24  before the fluid drains through the ball bearing  12  and the weir  28 . 
     In addition, the orientation of the lubricant port  30  within the system  10  relative to the weir  28  must be carefully determined with consideration given to the dominant rotation direction  56  of each bearing  12 . Preferably, for an anti-clockwise-spinning bearing  12  in the system  10  shown in  FIG. 1 a   , the lubricant port  30  is located at approximately the 10:30 position under normal operating conditions. In this configuration, the lubricant port  30  feeds lubricant into the bearing pocket  24  and the bearing  12  so that the force of gravity draws the lubricant down towards the bottom of the bearing pocket  24 . Advantageously, a sufficient amount of lubricant becomes entrained in the bearing  12 . If, however, the dominant rotation direction  56  of the bearing  12  was reversed, lubricant would be drawn by gravity against the rotation of the clockwise-spinning bearing  12  and an oversupply of lubricant would result. An oversupply of lubricant can cause frictional losses, and premature bearing wear. In  FIG. 1 b   , the weir  28  is at the 6 o&#39;clock position, the levy contour  42  is required to prevent the bearing  12  from being provided with inadequate lubricant supply. Inadequate lubricant supply to the bearing  12  can cause frictional losses, and premature bearing wear. In an extreme operating condition, like that depicted in  FIG. 1 b   , lubricant enters the bearing housing  14  at approximately the 11:30 position, and the levy contour  42  causes lubricant to pool between the lubricant port  30  and the ridge  48  of the contour  42 . The lubricant pooling allows adequate lubricant supply to the bearing  12  prior to the lubricant exiting the housing  14 . 
     In  FIGS. 1 a  and 1 b   , the housing  14  is divided into two radial halves by reference line A. With reference to the two halves of the clock face, the position and three-dimensional shape of the levy contour  42  on the annular flange  26  of the bearing housing  14  is also determined by the position of the lubricant port  30 , weir  28 , and with deference to the maximum g-force or grade to which the system  10  will likely be exposed. In one aspect, the levy contour  42  is cast into the housing  14 , and the three-dimensional shape of the levy contour  42  is machined or otherwise refined. The levy  42  is positioned so that the lubricant port  30  is towards the 12 o&#39;clock position of the clock face, and the levy  42  on the same half of the clock reference below the lubricant port  30 . That is, if the lubricant port  30  is positioned on the 9 o&#39;clock half of the housing  14 , then the levy  42  is also positioned primarily on the 9 o&#39;clock half of the housing  14  and below the lubricant port. In this configuration, lubricant runs down the levy  42  side of the bearing housing  14 . 
     Additionally, the system  10  is not symmetrical about either of reference line A or B. At rest, with no rotating components, lubricant that enters the housing  14  at or above the position of the levy  42  will pool to the level of reference line “P”, the pooling thereby allowing the lubricant to enter the bearing  12 , and then flow to the weir  28 . Additionally, at rest, lubricant that enters the system  10  below or on the opposite side of the bearing housing  14  from the levy  44  will flow directly into the weir  28 . 
     Turning now to  FIG. 2 , a partial cross sectional view through the housing  14  and bearing  12  is shown. The cross section is taken at the location of the weir  28  from the perspective indicated in  FIG. 1 a   . The weir  28  extends axially from a portion of the flange  26  through part of the flange axial depth “h”, through the cylindrical portion  38  and through the bearing seat  36 . The bearing  12  rests partially within the bearing seat  36  and the outer race  18  is adjacent to the bearing seat radial wall  40 . A portion of the bearing  12  extends beyond the bearing pocket open end  32 . Under normal conditions, as shown in  FIG. 1 a   , the weir  28  maintains a lubricant pool level that adequately lubricates the bearing  12 . To maintain the lubricant pool level, the weir  28  provides an egress for lubricant in the housing  14 . When the lubricant pool level reaches the weir first edge  52 , lubricant enters the weir  28  and flows through the weir  28  along weir flow line “f1”. As the lubricant flows along flow line “f1”, the lubricant circumvents the bearing  12 , thereby providing less lubrication to the bearing  12 . Under normal circumstances, when the weir  28  is positioned such that the lubricant pool level reaches one half of the bottom bearing ball  22  height, the amount of lubricant entrained in the bearing  12  provides adequate lubrication. Under extreme operating conditions, as shown in  FIG. 1 b   , the weir  28  operates to efficiently allow lubricant to flow out of the housing  14  without interacting with the bearing  12 . 
     Turning now to  FIG. 3 , a partial cross sectional view through the housing  14  and bearing  12  is shown. The cross section is taken at the location of the levy maximum axial depth  44  and levy maximum radial height  46 , from the perspective indicated in  FIG. 1 a   . The levy contour  42  extends axially from a portion of the flange  26  across the flange axial depth “h”, substantially across the cylinder wall  38 . The maximum axial depth  44  is located at the bearing seat radial wall  40  and the levy contour  42  slopes to an axial depth less than the maximum axial depth  44  as the contour  42  extends radially inward to the maximum radial height  46 . As in  FIG. 2 , the bearing  12  rests partially within the bearing seat  36  and the outer race  18  abuts the bearing seat radial wall  40 . A portion of the bearing  12  extends beyond bearing pocket open end  32 . Under normal conditions, as shown in  FIG. 1 a   , the levy contour  42  has very little impact on lubricant flow into the bearing  12  or into the weir  28 . However, when the vehicle is in an extreme operating condition, like the condition of  FIG. 1 b   , the levy contour  42  impedes lubricant flow into the weir. By impeding the flow of lubricant, the levy contour  42  causes a portion of the lubricant flow to pool between the lubricant port  30 , the levy contour  42 , and the bearing  12 . The flow lines “F2”, “F3”, and “F4” depict the flow direction of the lubricant from a lubricant pool between the levy contour  42  and the bearing  12  to the side of the bearing  12  opposite the levy contour  42 . As the lubricant pools between the levy contour  42  and the bearing  12 , some of the lubricant enters and becomes entrained in the bearing  12 , thereby causing the bearing  12  to be lubricated. Under extreme operating conditions, the levy contour  42  provides lubricant to the bearing  12  rather than allowing the lubricant to travel directly to the weir  28  without first lubricating the bearing  12 . 
     The features and components of the present invention described above, such as the annular flange  26 , lubricant port  40 , and a levy contour  42  cast or integrally formed in the bearing housing  14  are merely exemplary in nature, and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.