Abstract:
A bearing apparatus includes a housing including a body with a first end face spaced apart from a second end face, and a housing bore extending through the body from the first end face to the second end face along a main axis, the body further including a plurality of cooling passages.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates generally to bearings and more particularly to bearing housings for use with plain bearings. 
         [0002]    Various types of bearings are known and used for mounting shafts and other cylindrical structures for rotation with low friction. One particular type of bearing is a so-called “plain” bearing (or bushing) which comprises a cylindrical sleeve made of a material which provides a low coefficient of friction with the intended shaft material. 
         [0003]    Plain bearings are typically carried or mounted in a housing which serves to support the bearing and provide a means for mounting the bearing to a static structure. 
         [0004]    One problem with plain bearings is mounted in this manner is that they are subject to overheating because of an inability to transfer heat away from the bearing. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    This problem is addressed by a bearing housing incorporating a plurality of cooling passages. 
         [0006]    According to one aspect of the technology described herein, a bearing apparatus includes a housing including a body with a first end face spaced apart from a second end face, and a housing bore extending through the body from the first end face to the second end face along a main axis, the body further including a plurality of cooling passages. 
         [0007]    According to another aspect of the technology described herein, a bearing apparatus includes: a housing including a body with a first end face spaced apart from a second end face, and a housing bore extending through the body from the first end face to second end face along a main axis, the body further including a plurality of cooling passages; a bearing received in the housing bore, the bearing defining a bearing bore; and a shaft mounted for rotation in the bearing bore. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The invention may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures, in which: 
           [0009]      FIG. 1  is a top plan view showing an exemplary bearing housing; 
           [0010]      FIG. 2  is a cross-sectional view of the bearing housing shown in  FIG. 1 ; 
           [0011]      FIG. 3  is a top plan view showing a modification of the bearing housing of  FIG. 1 ; 
           [0012]      FIG. 4  is a cross-sectional view of the bearing housing shown in  FIG. 3 ; 
           [0013]      FIG. 5  is a top plan view showing another exemplary bearing housing; and 
           [0014]      FIG. 6  is a cross-sectional view of the bearing housing shown in  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    Referring to the drawings wherein identical reference numerals denote the same elements throughout the various views,  FIGS. 1 and 2  illustrate an exemplary bearing housing  10 . In general the bearing housing  10  has a body  12  with upper and lower surfaces  14  and  16  respectively (also referred to herein as end faces), and a peripheral flange  18  which may incorporate mounting holes  20 . 
         [0016]    The bearing housing  10  has a housing bore  22  formed therethrough parallel to a main axis “A”, and a bearing  24  is received in the housing bore  22 . The bearing  24  is generally cylindrical and includes a bearing bore  26  sized to receive a shaft  28  (the shaft  28  is removed for clarity in  FIG. 1  and is shown in  FIG. 2 ). Nonlimiting examples of alloys suitable for the shaft  28  include iron, steel, and aluminum. The bearing  24  is a “plain bearing”, also referred to as a bushing, which achieves a friction reducing effect through choice of materials. In general the bearing  24  may be made from a material which is softer (e.g. has a lower hardness) than the shaft  28  and/or has self-lubricating properties. Nonlimiting examples of materials known for use as bearings include brass, bronze, lead, the tin- or lead-based alloys which are commonly referred to as Babbitt metal, graphite, and plastics, and various combinations and alloys thereof. The bearing  24  may be provided with one or more coatings or treatments to improve its wear resistance and/or reduce friction. It will be understood that the housing described herein could be used with other types of bearings such as rolling element bearings or hydrodynamic bearings. 
         [0017]    The bearing  24  is stationary within the housing  10 . The housing bore  22  and the outer diameter of the bearing  24  may be sized to provide an appropriate class of fit, for example a press-fit. Alternatively or in addition to the press-fit, the bearing  24  may be retained in the bearing housing  10  using means such as a mechanical joint, or one or more mechanical fasteners (not shown). 
         [0018]    The bearing housing  10  may be constructed of a material having adequate strength to support and mount the bearing  24 , for example a metal alloy. Preferably, the bearing housing  10  is made from a material having a high thermal conductivity. Nonlimiting examples of materials having high thermal conductivity include metals such as aluminum, magnesium, and copper, and their alloys. 
         [0019]    The bearing housing  10  has a plurality of cooling passages  30  formed therein. More specifically, an array of cooling passages  30  pass through the bulk of the bearing housing  10  in a location in relatively close proximity to the housing bore  22 . In the illustrated example, a plurality of circular cross-section cooling passages  30  are disposed in a ring about the housing bore  22 . In the example shown in  FIGS. 1 and 2 , the long axes “B” of the cooling passages  30  extend parallel to the main axis A. It will be understood the cooling passages  30  may be placed in any orientation. For example,  FIGS. 3 and 4  show a variation of the bearing housing (labeled  10 ′) which includes cooling passages  30 ′ whose long axes “C” extend perpendicular to the main axis A. 
         [0020]    In operation, the combination of mechanical load and rotation of the shaft  28  within the bearing  24  results in frictional heat generation. This heat energy is transferred to the bearing  24  and subsequently into the bearing housing  10  through conductive heat transfer. Many different designs of plain bearings are commercially available. Each specific bearing design can handle a certain speed-load combination characterized by a factor “PV”, where P represents the pressure or load, and V is velocity or speed. Generally, the higher the PV factor, the more expensive the bearing. The presence of the cooling passages  30  permits a flow of air or other fluid to transfer the heat away from the bearing housing  10 . The presence of the cooling passages  30  increases the surface area available for convection heat transfer, and also reduces the distance that heat energy must travel through conduction through the wall thickness of the bearing housing  10 , before reaching a lower temperature environment. The presence of the cooling passages  30  in conjunction with the use of a material with a high thermal conductivity will provide improved heat transfer and in many cases permit the use of a less capable bearing than would otherwise be required. For example it may permit the use of a less expensive plain bearing in place of a more expensive plain bearing, or it may permit the use of a plain bearing instead of a more expensive rolling element bearing or hydrodynamic bearing. 
         [0021]    The concept of employing cooling passages may be extended to other types of bearing housings and/or support structures. For example  FIGS. 5 and 6  illustrate an alternative bearing housing  100  having upper and lower surfaces  114  and  116  respectively (also referred to herein as end faces). The bearing housing  100  is generally similar in construction to the bearing housing  10  described above. Elements of the bearing housing  100  not specifically described may be considered to be identical to the bearing housing  10 . A peripheral surface  118  of the bearing housing  100  has an arcuate shape (e.g. convex) so that the bearing housing  100  can be placed in a mount (not shown) which permits the bearing housing  100  to pivot in operation. 
         [0022]    The bearing housing  100  has an outer bore  122  formed therethrough. A bearing  124  is received in the outer bore  122  and includes an inner bore  126  sized to receive a shaft  28  (the shaft  28  is removed for clarity in  FIG. 5  and is shown in  FIG. 6 ). The bearing  124  is a “plain bearing” as described above. 
         [0023]    The bearing housing  100  has a plurality of cooling passages  130  formed therein. More specifically, an array of cooling passages  130  pass through the bulk of the bearing housing  100  in a location in relatively close proximity to the outer bore  122 . In the illustrated example, a plurality of circular cross-section cooling passages  130  are disposed in a ring about the outer bore  122  and extend parallel to the main axis A. The cooling passages  130  function in the same manner as the cooling passages  30  described above. 
         [0024]    The foregoing has described a bearing housing. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. 
         [0025]    Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. 
         [0026]    The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.