Patent Publication Number: US-2017356497-A1

Title: Bearing race

Description:
TECHNICAL FIELD 
     The present disclosure relates to parts for bearings. More particularly, the present disclosure relates to a bearing race. 
     BACKGROUND 
     The use of bearings as friction reducing devices is well known in the art. For example, to render a shaft rotatable with respect to a stationary housing of a motor, a bearing may be provided between the shaft and the housing of the motor. 
     Lubricants may typically be provided to facilitate operation of the bearing, for example by introducing lubricant to the rolling elements and races of a bearing when assembling, or packing, the bearing. Lubricants deteriorate with use leading to wear on the bearing races unless the lubricant is replaced periodically. 
     PCT publication WO2015/091728 discloses a rolling element for a bearing that is at least partially constituted of a first material being printed via an additive manufacturing process to define at least one channel open to an outer surface of the rolling element. The channel is configured to transport, in use, a lubricant from a hollow structure within the rolling element to the outer surface. Distribution of lubricant from such rolling elements may sometimes be non-uniform along a bearing race during use, leading to the possibility of wear in portions of the bearing race where little lubricant is present. Hence, there is a need for a bearing which addresses, or at least partially ameliorates, these challenges with bearing lubrication. 
     SUMMARY OF THE DISCLOSURE 
     In an aspect of the present disclosure, a bearing race comprises a surface having a plurality of pores formed therein, a lubricant being provided in the pores. 
     In another aspect of the present disclosure, a method of manufacturing a bearing race comprises producing the bearing race using at least an additive manufacturing process, the bearing race including a surface having a plurality of pores formed therein. The method further comprises providing a lubricant within the pores. 
     Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cutaway perspective view of an exemplary bearing with inner and outer races, in accordance with an embodiment of the present disclosure; 
         FIGS. 2-8  are enlarged perspective views of cutaway sections of a bearing race, in accordance with various embodiments of the present disclosure; and 
         FIG. 9  is a flow chart depicting a method of manufacturing a bearing race, in accordance with an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Wherever possible, the same reference numbers will be used throughout the drawings to refer to same or like parts. Moreover, references to various elements described herein are made collectively or individually when there may be more than one element of the same type. However, such references are merely exemplary in nature. It may be noted that any reference to elements in the singular may also be construed to relate to the plural and vice-versa without limiting the scope of the disclosure to the exact number or type of such elements unless set forth explicitly in the appended claims. 
     The present disclosure relates to a bearing race having a surface thereof provided with a plurality of pores in which lubricant is provided.  FIG. 1  shows an exemplary bearing  100  in which embodiments of the present disclosure may be implemented. As shown, the bearing  100  includes an inner bearing race  102 , an outer bearing race  104 . The bearing races  102 ,  104  each have an inner surface  124 ,  122  and an outer surface  126 ,  120 , respectively. The bearing  100  also includes a plurality of rolling elements  110  rotatably supported between the inner surfaces  124 ,  122  of the bearing races  102 ,  104 . Each rolling element  110  is spaced apart from adjacent rolling elements  110  by a bearing cage  106 . 
     The inner surfaces  124 ,  122  of the bearing races  102 ,  104  each have a load bearing zone  112  which contact the rolling elements  110 . The inner surfaces  124 ,  122  of the bearing races  102 ,  104  each have a plurality of pores (not shown in  FIG. 1 ) formed therein. A lubricant (not shown in  FIG. 1 ) is provided in the pores to lubricate the bearing races  102 ,  104 . 
     In the illustrated example of  FIG. 1 , each rolling element  110  is embodied in the form of a spherical ball that is rotatably disposed between the inner bearing race  102  and the outer bearing race  104 . Although the rolling elements  110  are being depicted as spherical balls in the example of  FIG. 1 , the term “rolling element” is not limited to the spherical balls disclosed herein. Where the bearing is of a type other than the spherical ball bearing type shown in  FIG. 1 , various other types of rolling elements including, but not limited to, cylindrical rollers, needle rollers, gearwheel rollers, and the like may be used in lieu of the spherical balls to form the rolling elements  110  for that type of bearing. In any case, it will be appreciated that regardless of the type of rolling elements used, embodiments disclosed herein can be similarly applied to various other types of bearings known in the art without deviating from the spirit of the present disclosure. 
     Various configurations of inner and outer bearing races are possible without departing from the spirit of the present disclosure. Exemplary embodiments are described below with reference to  FIG. 2  to  FIG. 8 . Each of these embodiments are described with reference to cutaway sections of a bearing race, and it will be appreciated that the section may be from the inner race  102  and/or the outer race  104  of  FIG. 1 . 
     Referring to  FIG. 2 , a cutaway section  202  of a bearing race  114  is depicted in accordance with an embodiment of this disclosure. As shown in  FIG. 2 , the bearing race  114  has a porous surface  212  having a plurality of pores  216  formed therein. The porous surface  212  is disposed towards the rolling elements  110  of the bearing  100  (refer to  FIG. 1 ). The porous surface  212  includes a load bearing zone  112  e.g., the load bearing zone  112  of the inner bearing race  102  or the load bearing zone  112  of the outer bearing race  104  with which the rolling elements  110  are disposed in contact. The contact established between the load bearing zone  112  and each of the rolling elements  110  is inclusive of either or both of rolling and sliding contact. A lubricant (not shown) is provided in the pores  216 . This provides lubrication to at least the load bearing zone  112 , where contact between the bearing race  114  and rolling elements  110  occurs. 
     As shown in the illustrated embodiment of  FIG. 2 , the pores  216  disposed on the porous surface  212  are configured to provide lubricant to the load bearing zone  112  of the bearing race  114 . Each of the pores  216  on the surface  212  may extend into a body  220  of the bearing race  114  as pathways  218 . The pathways  218  may form a porous volume  210  of the body  220 . In one embodiment, the pathways  218  are configured to fluidly communicate the lubricant to the pores  216 , for instance via capillary action. In an alternative embodiment, lubricant in the pathways  218  lubricates the bearing race  114  the porous surface  212  wears through use to expose the pathways  218  and lubricant provided therein. 
     In embodiments herein, the pores  216  could be located on any portion of an outer surface  214  of the bearing race  114 . In one embodiment, the porous volume  210  comprises substantially all of the body  220 . For example, as shown in  FIG. 2 , the pores  216  are configured on all surfaces of the body  220  i.e., outer or side surfaces  214  in addition to the porous surface  212 . As the pores  216  are configured on the outer surface  214  in addition to the porous surface  212  in the illustrated example of  FIG. 2 , the pores  216  may act as a means to fluidly communicate lubricant between the porous surface  212  and a remainder of the outer surface  214  associated with the body  220 . 
     In an embodiment, the bearing race  114  of  FIG. 2  may be embodied as the outer bearing race  104  of the bearing  100  shown in  FIG. 1 . In this embodiment, the porous surface  212  may be located on an inner surface  122  of the outer bearing race  104  (refer to  FIG. 1 ) that is disposed facing the rolling elements  110 . As the load bearing zone  112  is also located on the inner surface  122  of the outer bearing race  104 , the pores  216  on the porous surface  212  may deliver lubricant to the load bearing zone  112  of the outer bearing race  104  and lubricate a movement of the rolling elements  110  thereon. 
     In another embodiment, the bearing race  114  of  FIG. 2  may be embodied as the inner bearing race  102  of the bearing  100  shown in  FIG. 1 . In this embodiment, the porous surface  212  may be located on an inner surface  124  of the inner bearing race  102  (refer to  FIG. 1 ) which would be disposed facing the rolling elements  110 . As the load bearing zone  112  would be located on the inner surface  124  of the inner bearing race  102 , the pores  216  on the porous surface  212  may be configured to deliver lubricant to the load bearing zone  112  of the inner bearing race  102  and lubricate a movement of the rolling elements  110  thereon. Although the load bearing zones  112  of the inner and outer races  102 ,  104  associated with the exemplary bearing  100  of  FIG. 1  are configured to act as radial load bearing zones, in other types of bearings, the load bearing zone  112  may be configured to act as an axial load bearing zone or a load bearing zone that is capable of handling both axial and radial loads, each of which may be incident on the rolling elements  110  of the bearing  100 . 
     With regards to the illustrated embodiment of  FIG. 2 , the cutaway section  202  of the bearing race  114  may be regarded as being representative of at least one of the inner bearing race  102  and the outer bearing race  104 . In an example, the outer bearing race  104  alone may be provided with a porous surface. In another example, the inner bearing race  102  alone may be provided with a porous surface. In yet another example, both the inner and outer races  102 ,  104  of the bearing  100  may each be provided with a porous surface. 
     In embodiments of this disclosure, the pores  216  of the bearing race  114  may be filled or impregnated with a predetermined amount of lubricant. For example, lubricant may be injected or pressed into the pores  216  of the bearing race  114  so that the pathways  218  are filled with a predetermined amount of lubricant. In another example, the bearing race  114  may be soaked in the lubricant such that the pores  216  are filled with the predetermined amount of lubricant. In another example, lubricant may be provided in the pores  216  and pathways  218  by an additive manufacturing process. In another embodiment, the lubricant may be provided to the bearing race  114  in a continuous manner. For example, the bearing race  114  may be fluidly connected to a source (not shown) configured to store the lubricant. The stored lubricant may be continuously supplied from the source to the load bearing zone  112  of the bearing race  114  with the help of a conduit (not shown). 
     Further, in embodiments of this disclosure, the pores  216  are configured to dispense the lubricant based on a capillary action of the lubricant with the body  220  of the bearing race  114 . Each pore  216  may have a diameter in the range of 0.01 micron to 500 microns. In one example, a diameter of each pore  216  may be about 0.2 microns. In another example, a diameter of each pore  216  may be about 20 microns. In yet another example, a diameter of each pore  216  may be about 250 microns. However, it may be noted that a diameter of each pore  216  may vary from one application to another depending on specific requirements of an application. A selection of the diameter for each pore  216  may be made taking into account factors including, but not limited to, a viscosity of the lubricant, an amount of lubricant to be dispensed onto the load bearing zone  112  in unit time (i.e., flow rate), etc. 
     Referring to  FIG. 3 , a cutaway section  204  of a bearing race  114  is depicted in accordance with another embodiment of this disclosure. As shown, the body  220  of the bearing race  114  includes a non-porous portion  222  remote from the porous surface  212 . The non-porous portion  222  disclosed herein may form part of an outer surface of a race e.g., a sidewall  116  of the outer bearing race  104  or a sidewall  118  of the inner bearing race  102  as shown in  FIG. 1 . Therefore, it may be noted that in embodiments of this disclosure, the bearing race  114  may essentially include pores  216  only on the porous surface  212 , and may or may not include pores  216  in other surfaces such as e.g., the sidewalls  118 ,  116  or outer surfaces  126 ,  120  of the inner bearing race  102  or the outer bearing race  104  respectively. 
     Referring now to  FIGS. 4-8 , illustrated are cutaway perspective views of the bearing race  114 , in accordance with various embodiments of the present disclosure. In an embodiment as shown in  FIG. 4 , a plurality of pathways  304  extend from the pores  216  on the porous surface  212  and terminate within the porous volume  210  of the body  220 . For example, if the bearing race  114  is embodied as the outer bearing race  104 , the pathways  304  may be configured to extend from the pores  216  on the porous surface  212  i.e., the inner surface  122  of the outer bearing race  104  and terminate prior to an outer surface  120  of the outer bearing race  104  (refer to  FIG. 1 ). In another example, if the bearing race  114  is embodied as the inner bearing race  102 , the pathways  304  may be configured to extend from the pores  216  on the porous surface  212  i.e., the inner surface  124  of the inner bearing race  102  and terminate prior to an outer surface  126  of the inner bearing race  102  (refer to  FIG. 1 ). As shown in  FIG. 4 , each pathway  304  is not in fluid communication with other pathways  304 . 
     In another embodiment as shown in  FIG. 5 , at least one reservoir  402  may be formed in the porous volume  210  of the body  220 . Each reservoir  402  may be configured i.e., sized and shaped so as to store a predetermined amount of lubricant therein. In an example, a geometry of each pathway  304  may be configured to have a polyhedral, ellipsoid or ovoid shape, or any other shape. As shown in  FIG. 5 , each pathway  304  may be in fluid communication with at least one reservoir  402 . 
     In the illustrated embodiment of  FIG. 6 , each of the pathways  304  is interconnected with an adjacent pathway  304  to form an interconnected network of pathways  304 . However, it is to be noted that the pathways  304  in a given bearing race  114  i.e., the inner bearing race  102 , the outer bearing race  104 , and/or the bearing cage  106  may be configured to represent stand-alone pathways or interconnected pathways depending on specific requirements associated with the given bearing race  114 , for example, depending on an amount of lubricant to be dispensed to the load bearing zone  112  associated with the given bearing race  114 . In fact, it can also be contemplated by one skilled in the art to configure some of the pathways  304  in the bearing race  114  as stand-alone pathways while the remaining pathways  304  from the same bearing race  114  may be interconnected with one another to represent an interconnected matrix of pathways. Therefore, various configurations of the pathways  304  may be implemented by persons skilled in the art without deviating from the spirit of the present disclosure. 
     In an embodiment as shown in  FIG. 7 , the body  220  of the bearing race  114  includes a plurality of non-permeable portions  322  therein. The non-permeable portions  322  may divide the porous volume  210  into a plurality of porous sections  326 . Each of these porous volumes  326  may contain one or more pores  216  therein. Advantageously, each of these porous sections  326  has a corresponding porous surface portion  212  as shown. This arrangement may allow for e.g., the outer bearing race  104  or the inner bearing race  102  to provide lubrication within a specific area e.g., two or more spaced apart load bearing zones  328  of the bearing race  114  as shown in  FIG. 7 . 
     Alternatively, in another embodiment as shown in  FIG. 8 , a contiguous non-permeable wall  322  may be defined in the body  220  of the bearing race  114 . Such contiguous permeable wall  322  may be configured, for example, to prevent flow of the lubricant past the porous volume  210  of the bearing race  114 . 
     In one example, if the bearing race  114  of  FIG. 8  is embodied as the outer bearing race  104  of the bearing  100  shown in  FIG. 1 , the contiguous non-permeable wall  322  may be located adjacent the sidewalls  116  and the outer surface  120  of the outer bearing race  104 . This prevents lubricant from escaping from the sidewalls  116  and the outer surface  120  of the outer bearing race  104  while the pores  216  on the porous surface  212  of the bearing race  114  i.e., the outer bearing race  104  continue to deliver the lubricant to the load bearing zone  112  of the outer bearing race  104 . 
     In another example, if the bearing race  114  of  FIG. 8  is embodied as the inner bearing race  102  of the bearing  100  shown in  FIG. 1 , the contiguous non-permeable wall  322  may be located adjacent the sidewalls  118  and the outer surface  126  of the inner bearing race  102 . This prevents lubricant from escaping from the sidewalls  118  and the outer surface  126  of the inner bearing race  102  while the pores  216  on the porous surface  212  of the bearing race  114  i.e., the inner bearing race  102  continue to deliver the lubricant to the load bearing zone  112  of the inner bearing race  102 . 
     Various embodiments disclosed herein are to be taken in the illustrative and explanatory sense, and should in no way be construed as limiting of the present disclosure. All joinder references (e.g., attached, affixed, coupled, connected, and the like) are only used to aid the reader&#39;s understanding of the present disclosure, and may not create limitations, particularly as to the position, orientation, or use of the systems and/or methods disclosed herein. Therefore, joinder references, if any, are to be construed broadly. Moreover, such joinder references do not necessarily infer that two elements are directly connected to each other. 
     Additionally, all numerical terms, such as, but not limited to, “first”, “second”, “third”, “primary”, “secondary” or any other ordinary and/or numerical terms, should also be taken only as identifiers, to assist the reader&#39;s understanding of the various elements, embodiments, variations and/or modifications of the present disclosure, and may not create any limitations, particularly as to the order, or preference, of any element, embodiment, variation and/or modification relative to, or over, another element, embodiment, variation and/or modification. 
     It is to be understood that individual features shown or described for one embodiment may be combined with individual features shown or described for another embodiment. The above described implementation does not in any way limit the scope of the present disclosure. Therefore, it is to be understood that although some features are shown or described to illustrate the use of the present disclosure in the context of functional segments, such features may be omitted from the scope of the present disclosure without departing from the spirit of the present disclosure as defined in the appended claims. 
     INDUSTRIAL APPLICABILITY 
       FIG. 9  illustrates a method  900  for manufacturing a bearing race, in accordance with an embodiment of the present disclosure. The method  900  is hereinafter explained in conjunction with  FIGS. 1-3 . 
     At step  902 , the method  900  includes producing the bearing race  114  using at least an additive manufacturing process in which the bearing race  114  is configured to have plurality of pores formed in a surface thereof. In embodiments of this disclosure, the bearing race  114  is beneficially produced from use of an additive manufacturing process in which material is deposited in a layer-by-layer manner, but essentially the individual layers are successively deposited such that the bearing race  114  is rendered contiguous. Moreover, in the additive manufacturing process, similar or dissimilar materials may be used. When dissimilar materials are being used to form the bearing race  114 , ratios by weight or volume between the dissimilar materials may be advantageously varied from one layer to another depending on specific requirements of an application including, but not limited to, weight, density, porosity, and the like. 
     At step  904 , a lubricant is provided within the pores  216  formed in the body  220  of the bearing race  114 . In an embodiment, the method  900  also includes forming at least one reservoir  402  in the body  220  and providing lubricant therein. Where a suitable lubricant is available, the lubricant may be provided by an additive manufacturing process. 
     The steps  902  to  904  are only illustrative and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein. 
     Embodiments of the present disclosure have applicability for use in lubricating the rolling elements and the bearing races of a bearing so that a service life of the bearing may be prolonged. 
     With implementation of embodiments disclosed herein, frequent maintenance such as that typically required for previously known bearing designs may be reduced. As the bearing elements of the present disclosure are made porous, lubricant may be provided to the load bearing zone through the pores. A sizing of the pores and the pathways helps to perform both a retention of the lubricant within the porous volume, and a dispensing of the lubricant onto the rolling elements at a required flow rate. Advantageously, as the bearing races are configured to store and dispense lubricant onto the rolling elements, a service life of the bearing may be prolonged. 
     While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems, methods and processes without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.