Patent Publication Number: US-2004047526-A1

Title: Roller bearing with oil ring lubrication

Description:
BACKGROUND OF THE INVENTION  
       [0001] The present invention relates generally to bearing housings and more particularly a roller bearing housing with integrated end plates and split construction to facilitate installation and servicing.  
       [0002] Roller bearings are common devices employed to allow for rotation of various elements. The bearings reduce unwanted friction by providing a smooth inner and outer surface against which the rollers travel. A shaft can be inserted through the central opening of the bearing thereby allowing securing of the shaft as it rotates. The shaft may then be engaged to drive various machines, such as fans, turbines or a wide range of other machines. The rotation of the shaft, in conjunction with the bearing, typically subjects the bearing to radial and thrust loads. In order to support the roller bearing against subjected loads that induce unwarranted movement, the roller bearing is set inside a housing. Additionally, the housing may protect the bearing from contaminants and may also provide the roller bearing with a source of lubrication.  
       [0003] Traditionally, housings incorporating oil rings for lubrication are constructed from a four-piece assembly consisting of an upper piece, a lower piece, and two endplates. After the upper and lower pieces are fastened together, the two independent endplates are subsequently secured to the partially assembled housing. The upper and lower pieces, as assembled, surround the roller bearing and secure the roller bearing in place while the independent endplates complete the enclosure of the roller bearing and provide a passthrough for the shaft. The ingress and egress of materials between the housing and shaft passthrough is resisted by seal assemblies located within the independent endplates.  
       [0004] The traditional use of four distinct pieces increases the cost of fabrication and also increases the number of joints at which leakage may occur. A need exists for a bearing housing incorporating an oil ring lubrication arrangement, but that uses fewer pieces and decreases the number of joints at which potential leakage may occur.  
       SUMMARY OF THE INVENTION  
       [0005] The invention features a bearing housing that employs fewer structural components than traditionally used. In one embodiment, the endplates are integrated into the upper and lower housing structures such that essentially only two prefabricated pieces are required to form the bearing housing. Additionally, the integrated endplates house seal assemblies that prevent the ingress and egress of contaminants between the shaft and the bearing housing. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0006] The foregoing and other advantages and features of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:  
     [0007]FIG. 1 is a perspective view of an assembled bearing housing in accordance with aspects of the present technique having a shaft incorporated therethrough;  
     [0008]FIG. 2 is an exploded perspective view of the bearing housing illustrated in FIG. 1;  
     [0009]FIG. 3 is a cross-sectional view along line  3 - 3  of the assembled bearing housing as illustrated in FIG. 1;  
     [0010]FIG. 4 is a cross-sectional view along line  4 - 4  of the bearing housing shown in FIG. 3, wherein the view plane cuts in front of the roller bearing as to show the integrated end plates of the upper and lower housing; and  
     [0011]FIG. 5 is a cross-sectional view along line  5 - 5  of the bearing housing as illustrated in FIG. 3, wherein the view plane passes behind the roller bearing as to show the roller bearing and its support structures. 
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS  
     [0012] For purposes of convenience, the present invention will be described with respect to a two-piece roller bearing housing. However, it will be appreciated that this invention is equally applicable to various other types of bearings as well. Moreover, the bearing housing need not be limited to two-piece housings.  
     [0013]FIG. 1 is a perspective view of an assembled bearing housing  10 . Effectively, the bearing housing  10  is constructed by securely fastening the upper housing  12  with the lower housing  14 . The bearing housing  10  has a set of securing flanges  16  located on the upper side of the lower housing  14  and the lower side of the upper housing  12  that are aligned so as to allow for securely bolting the two housing structures together. FIG. 1 also depicts a pair of mounting flanges  18  located on the lower sides of the lower housing  14 . The mounting flanges  18  allow for the entire bearing housing  10  to be securely fastened to a base or other mounting assembly (not shown). As assembled, the shaft  20  is protected against excessive wear during rotation by a set of sleeve assemblies  22  located at the entry and exit portals of the bearing housing  10 . For purposes of maintenance or transportation, a lifting hook  24  provides a secure connection to the bearing housing  10 . As illustrated by the exemplary embodiment, the entire bearing housing  10  may, effectively, comprise of two separate housing structures such that only one joint of concern exists between the two.  
     [0014]FIG. 2 shows the structure of FIG. 1 in exploded perspective and further illustrates some of the internal components of the bearing housing  10 . The exploded view permits depiction of a roller bearing  26 . The shaft  20 , that is supported by the bearing housing  10 , passes securely through the open center of the roller bearing  26 . The free moving nature of the inner race of the roller bearing  26  allows for secured rotation of the shaft  20  along its given axis of rotation. The sleeves  22 , located on opposite ends of the roller bearing  26 , protect the shaft  20  from wear induced by the rotation of the shaft against the bearing housing  10  or seals as described below. Along the shaft  20  and located between the roller bearing  26  and the appropriate sleeve  22  rides an oil ring  28 . The oil ring  28  accesses lubricating fluid from a sump  30  formed in a lower region of lower housing  14  to lubricate the roller bearing  26 .  
     [0015] In the exemplary embodiment illustrated, the integration of the essential elements of the bearing housing into two distinct components limits the ingress of contaminants that could harmfully affect the operation of the roller bearing. Moreover, the exemplary two-piece bearing housing limits leakage of oil from joints between the upper and lower housing portions. Additionally and for purposes of maintenance, for example, the sump  30  may be drained of oil by a set of oil drains  32 . Accessibility to the oil drains  32  is provided by corresponding oil drain plugs  34 . It should be noted that the use of the bearing housing  10  as providing an oil reservoir or sump is presently preferred, but other particular designs not incorporating such features may also be enabled by the present technique.  
     [0016] The exploded view of FIG. 2 also permits depiction of a set of seal tracks or groves  36 . As shown, the seal tracks  36  are semicircular recesses formed within the integrated end plates of the upper housing  12  and the lower housing  14 , respectively. The curvature of each seal track  36  accommodates a seal assembly  38 , which is preferably disposed therein. Each seal assembly  38  may be of any suitable type. However, for exemplary purposes a compound seal having face-rubbing portion and a labyrinth seal is presented. Upon the securing of the upper housing  12  to the lower housing  14 , each seal track  36  becomes a continuous pathway housing the respective seal assembly and circumscribing the shaft  20 . In the instant embodiment, each seal assembly  22  rides against a respective sleeve  22  so as to isolate the interior of the bearing housing  10  from outside contaminants, and to maintain lubricant within the housing. It should be noted that the seal assemblies  38  need not necessarily be disposed of within the seal tracks  36 , and that the aforementioned seal tracks  36  are intended to constitute an exemplary embodiment. Alternatively, the seal tracks  36  may be removed or altered and a thin seal assembly  38  may be employed.  
     [0017]FIG. 3 is a cross-sectional view of the assembly of FIG. 1 along line  3 - 3 . This view provides an illustration of the bearing housing assembly  10  along a plane parallel to the axis of rotation of the shaft  20 . As depicted, the roller bearing  26  rests securely on bearing support  40 . The bearing support  40  is structurally integrated into the bottom portion of lower housing  14 . The radius of curvature of the bearing support  40  essentially matches that of the roller bearing  26 . Additionally, within the lower bearing support  40  a lower bearing channel  42  is formed. It is within the lower bearing channel  42  that the roller bearing  26  rests. The depth of the lower bearing channel  42  is such as to prevent lateral movement of the roller bearing  26  when loaded. The width of the lower bearing channel  40  is maintained within close tolerance to the width of the roller bearing  26  to prevent unnecessary lateral movement of the roller bearing  26 . Correspondingly, an upper bearing channel  44  is formed within the top portion of the upper housing  12 . The curvature of the upper bearing channel  44  also generally matches that of the roller bearing  26 . Similarly to the lower bearing channel  40 , the width and depth tolerances of the upper bearing channel  44  are maintained with respect to the dimensions of the roller bearing  26  to prevent lateral movement thereof. The tolerances between the bearing  26  and the channels  42  and  44  may create a friction fit and so as to prevent the rotation outer race of bearing  26 . As assembled, the upper bearing channel  44  in conjunction with the lower bearing channel  42  allow the roller bearing  26  to support radial loads as applied by the shaft  20 . Additionally, the bearing support  40  also supports thrust loads of the shaft  20  upon the roller bearing  26 .  
     [0018] By supporting loading of the roller bearing  26 , the bearing support  40  relieves the seal assemblies  38  located in the lower housing  14  from any such loading by the shaft  20 . Accordingly, the wear upon the seal assemblies  38  is reduced. It should also be noted that in the illustrated embodiment the seal assemblies  38  located within the lower housing  14  are in fluid communication with the sump  30  via a set of seal drains  46 . The seal drains  46  direct excess lubricating fluid away from the seal assemblies  38  and return the lubricating fluid back to the sump  30 . The seal drains  46  reduce the likelihood of excess lubricating fluid escaping from the bearing housing  10  at the seal assemblies  38 . As stated above, an exemplary seal type for each seal assembly  38  includes face rubbing seals integral with labyrinth seals.  
     [0019] As shown in the illustrated embodiment, the seal assemblies  38  interact with a pair of sleeves  22  that are disposed on both sides of the roller bearing  26 . The sleeves  22  may be friction fitted onto the shaft  20 . If desired, however, other measures such as a set screws, for example, may be employed to secure the sleeves  22  to the shaft  20 . The sleeves  22  circumscribe the shaft  20  and extend from the roller bearing  26  to a point slightly beyond the integrated end plates of the upper housing  12  and lower housing  14 . The sleeves  22  may have integrated deflector rings  48  located at a position on the respective sleeve  22  such that the deflectors  48  are disposed between the roller bearing  26  and the integrated end plates of the upper housing  12  and lower housing  14 . The deflector  48  is provided to prevent contaminants that enter the bearing housing  2  from reaching and affecting the rotation of the roller bearing  26 .  
     [0020]FIG. 4 is a cross-sectional view of the assembled bearing housing  10  along line  4 - 4  as shown in FIG. 3. This view illustrates the interior of the bearing housing  10  along a plane perpendicular to the axis of rotation of the shaft  20  and in front of the roller bearing  26 . As shown, the upper housing  12  provides an oil inlet passage  50  through which a lubricating fluid may be inserted into the interior of the bearing housing  10 . The inlet passage  50  is then subsequently sealed through the use of an inlet plug  52 . Moreover, the mounting flanges  18 , as shown, are provided with passages through which bolts could secure the bearing housing  10  to a support surface (not shown). FIG. 4 also illustrates the contour and shape of the bearing support  40 .  
     [0021]FIG. 5 is a cross-sectional view of the bearing housing  10  as illustrated in FIG. 3 along line  5 - 5 . FIG. 5 illustrates the bearing housing  10  along a plane perpendicular to the axis of rotation of shaft  20  and located behind the roller bearing  26 . In this view, the oil ring  28  can be seen. The oil ring  28 , in the illustrated embodiment, may be a steel ring that loosely circumscribes the shaft  20  and one of the sleeves  22  as well as a set of oil ring supports  54 . The oil ring supports  54  are integrated into the bearing housing support  40 . As the shaft  20  and the sleeve  22  rotate, the friction between the sleeve  22  and the oil ring  28  induces rotation of the oil ring  28 . During each revolution of the oil ring  28 , it draws lubricating fluid from the sump  30  and subsequently carries the lubricating fluid to a contact point with the sleeve  22  and shaft  20 . The oil ring  28  then deposits the lubricating fluid such that free-rotation of the roller bearing  26  is assisted as is cooling and cleaning of the bearing assembly.  
     [0022] While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown in the drawings and have been described in detail herein by way of example only. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.