Patent Publication Number: US-2016230930-A9

Title: Housing With A Direct Flow Path For Hardware Lubrication

Description:
RELATED APPLICATIONS 
     This application is a divisional application of U.S. application Ser. No. 13/206,826, filed Aug. 10, 2011, which claims priority to U.S. Provisional Patent Application Ser. No. 61/373,465, filed Aug. 13, 2010, both which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     The present invention relates to a cast housing, and in particular to a cast housing of a transmission with an improved fluid path for lubricating a bearing. 
     A conventional transmission can include an outer cast housing that encloses gears, shafts, clutches, friction/reaction plates, variators, planetary gear sets, bearings, etc. The outer cast housing can be formed by a plurality of housings connected to one another. During operation, the internal components of the transmission can reach extreme temperatures and therefore require a means for cooling. A bearing, for example, requires a lubricant to be applied or sprayed into contact therewith in order to maintain the temperature of the bearing below a certain threshold. Once the bearing temperature exceeds the threshold, the bearing can fail causing potential damage to the transmission and negatively affecting its operation. 
     There are several conventional ways in which a bearing or other internal component is lubricated. One such way, for example, is to apply lubrication to the bearing before it is installed or assembled in the transmission. However, over a period of time the bearing needs additional lubrication, particularly if the bearing temperature reaches an extreme temperature. Therefore, a conventional transmission can include a plurality of lube circuits integrated therein. A pump can supply a lubricant to a plurality of lube circuits in the transmission. For example, a shaft can be drilled with lube holes to allow a lubricant to pass therethrough and provide sufficient lubrication to bearings and other internal components. 
     The lubricant can be a transmission fluid such as TranSynd™, which is a synthetic oil formulated by Castrol Ltd. One skilled in the art may know of other types of lubricants. During operation, the amount of torque and power generated by a transmission can put a significant amount of stress on a shaft in the transmission. This stress can limit the quantity and location of lube circuits formed in the shaft. In such instances, a bearing that would ordinarily be lubricated by a lubricant passing through a lube hole in the shaft may be lubricated in an alternative manner. Often times, the bearing may not receive enough lubrication and eventually fail, or the transmission may need to be redesigned such that more lubricant reaches the bearing. Alternatively, the bearing may need to be relocated inside the transmission where a nearby lube circuit is provided. In other designs, lubricant is directed through lube circuits which indirectly supply lubrication to the bearing. Again, the bearing may not receive enough lubrication and eventually overheat and/or fail. 
     Therefore, a need exists for a cast housing with an improved lube path integrated therein for providing sufficient lube to a bearing enclosed within the housing, particularly when a lube path cannot be integrally formed in a shaft. 
     SUMMARY OF THE INVENTION 
     In one exemplary embodiment of the present invention, a housing is provided that encloses a bearing. The housing includes a side wall upon which a lubricant is dispersed. The side wall has an angularly disposed portion. The housing also includes a collection area that is fluidly associated with the side wall. A fluid circuit is integrated with the side wall such that the fluid circuit is configured to direct the lubricant into the collection area. The collection area can be fluidly coupled to the bearing. In addition, the collection area and angularly disposed portion can be formed on opposite sides of the side wall. 
     In one embodiment, a transmission includes a bearing and a fluid source configured to provide fluid to the bearing. The transmission also includes a housing that encloses the bearing and fluid source. The housing has a side wall that defines a front face and a rear face such that the front face is opposite the rear face. The side wall is configured to receive fluid from the fluid source. The housing also includes a surface angularly disposed from the front face of the side wall and a collection area formed between the rear face of the side wall and the bearing. The collection area is fluidly associated with the surface and configured to collect fluid. A fluid circuit is defined along the front face and the surface and is configured to direct the fluid into the collection area. 
     In another embodiment, a housing for providing lubrication to a bearing includes a wall upon which a lubricant is dispersed. The wall has a first portion and a second portion such that the second portion is sloped from the first portion. The housing further includes a means for collecting the lubricant. The means for collecting is disposed adjacent to the bearing. The housing also includes a means for directing the lubricant from the wall to the means for collecting. The means for directing is fluidly associated with the means for collecting. 
     In a different embodiment, a method of lubricating a bearing in a housing of a transmission is provided. The housing includes a side wall that is defined by a first portion and a second portion. The second portion of the housing is angularly disposed from the first portion. The housing further includes a recessed portion defined between the side wall and the bearing. The method includes applying a lubricant to the side wall and directing the lubricant from the first portion to the second portion of the side wall. The lubricant is collected in the recessed portion and the bearing is lubricated with the collected lubricant. The method can further include guiding the lubricant along the first portion of the side wall. 
     An advantage associated with the various embodiments described above is the ability to provide sufficient lubrication to the bearing without providing a lube circuit through a shaft, particularly when doing so would weaken the shaft. Instead, the housing defines the lube circuit. A portion of the housing is angularly disposed such that the lubricant is directed to a collection area. As the lubricant is received in the collection area, the lubricant collects therein and provides the necessary amount of lubrication required to maintain the bearing temperature at a reasonable level. 
     Another advantage is the housing defines a direct lube path to the bearing. In other conventional lube circuits, the lube path is indirect and an insufficient amount of lubricant reaches the bearing. As described above, this causes an undesirable condition as the bearing can overheat and fail. In the above-described embodiments, however, the lube circuit defined by the housing receives the lubricant from a source and guides the lubricant to the collection area directly. As a result, a sufficient amount of lubricant is collected in the collection area to lubricate the bearing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned aspects of the present invention and the manner of obtaining them will become more apparent and the invention itself will be better understood by reference to the following description of the embodiments of the invention, taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a partial side elevation and cross-sectional view of a portion of a transmission housing with an improved lube passage; 
         FIG. 2  is a cross-sectional view of the housing of  FIG. 1 ; 
         FIG. 3  is a front elevation view of a portion of the housing of  FIG. 1 ; and 
         FIG. 4  is a side schematic view of the housing of  FIG. 1 . 
     
    
    
     Corresponding reference numerals are used to indicate corresponding parts throughout the several views. 
     DETAILED DESCRIPTION 
     The embodiments of the present invention described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of the present invention. 
     An exemplary embodiment of a housing  102  is shown in  FIG. 1 . The housing  102  can be any housing (e.g., engine, valve, etc.), but in this embodiment the housing  102  is part of a transmission  100  for a powered vehicle. In particular, the housing  102  can provide an enclosure for electrical and mechanical components. The housing  102  defines a plurality of walls that form the enclosure. The housing  102  can be formed of cast aluminum or any other metallic material. Alternatively, in another embodiment, the housing can be formed of a plastic or resin material. One skilled in the art can appreciate other materials from which the housing  102  can be formed. 
     As described above, the housing  102  in  FIG. 1  is an outer housing or main case of the transmission  100 . The housing  102  defines an inner wall  104  that encloses internal components. The housing  102  can define one or more inner walls  104  such that the overall enclosure is conical, cylindrical, frustoconical, cubical, or any other shape known to the skilled artisan. Other walls, e.g., side walls, can integrally be formed with the inner wall  104 . For example, in the embodiment of  FIG. 1 , a side wall  106  is formed near the top and bottom of the housing  102 . The side wall  106  is substantially perpendicular with respect to the inner wall  104  and protrudes radially inward therefrom. The thickness of the side wall  106  can vary along its length. For instance, in  FIG. 1 , a first portion  106 A of the side wall  106  has a greater thickness than a second portion  106 B disposed adjacent to the inner wall  104 . 
     The change in thickness of the side wall  106  can be attributed to the size and location of the electrical or mechanical components in contact with or in close proximity of the side wall  106 . In the illustrated embodiment, the housing  102  can at least partially enclose a variator  112 , a shaft  114 , a bearing  116 , a retaining nut  118 , and a bearing pilot  120 . The housing  102  can also enclose additional components that are not shown. Although a variator  112  is shown in  FIG. 1 , a pump or other fluid source can be enclosed within the housing  102 . As shown, the bearing pilot  120  is assembled inside the housing  102  and passes through an opening formed in the side wall  106 . The opening can be any shape including circular, square, rectangular, oval, etc. 
     The second portion  106 B of the side wall  106  defines a substantially vertical surface that is oriented towards the variator  112 . The first portion  106 A of the side wall  106 , however, defines a surface  108  that is angularly disposed or sloped from the second portion  106 B. The surface  108  can be sloped at an angle between 0° and 45°. In one embodiment, the surface  108  is disposed at an angle between 5° and 25°. In an advantageous embodiment, the surface  108  is disposed at about 15°. As shown, the surface  108  is oriented towards the bearing  116 . 
     In the embodiment of  FIG. 1 , the side wall  106  forms at least two faces. A front face  122  defines surface  108  and is oriented substantially towards the variator  112 . On the opposite side, a second face  124  is oriented substantially towards the bearing  116  and retaining nut  118 . A collection area  110  (e.g., recess) is formed in the housing  102  and is partially defined by the second face  124 . The collection area  110  is adjacent to the bearing  116  such that transmission fluid, for example, can collect or “pool” therein and lubricate the bearing  116 . As shown, the cross-section of the collection area  110  is substantially L-shaped to facilitate the passage of fluid to the bearing  116 . Although in the embodiment of  FIG. 1  the collection area  110  is partially defined by the bearing  116 , in other embodiments a different electrical or mechanical component can partially define the collection area  110 . In other words, any electrical or mechanical component that can be cooled by a fluid can be used for partially defining the collection area  110 . Regardless of the component, however, the housing  102  at least partially defines the collection area  110 , and in some embodiments the housing  102  may substantially define the entire collection area  110 . 
     In  FIG. 2 , a plurality of lube passages are shown. For example, the shaft  114  has a central passage  202  through which transmission fluid can travel. In addition, a pair of lube passages  204 ,  206  are fluidly coupled at one end to the central passage  202  and extend radially outward therefrom. Transmission fluid passing through the central passage  202  is directed through the pair of lube passages  204 ,  206  because a seal  208  blocks the fluid from exiting through the end of the shaft  114 . At the opposite end, the lube passages  204 ,  206  are unobstructed so that fluid can pass through the central passage  202  and exit through the passages  204 ,  206 . However, any fluid that passes through the central passage  202  and lube passages  204 ,  206  cannot be directed to the bearing  116 . The bearing  116  therefore is unable to be lubricated in this manner. 
     As described above, conventional lube circuits may include passages in the shaft  114  similar to lube passages  204 ,  206  that would direct fluid to the bearing. However, in this embodiment, the amount of torque and power exerted on the shaft  114  does not allow lube passages to be formed in the shaft  114  at locations adjacent to the bearing  116 . The shaft  114  is weakened by drilling or forming lube passages therein and thus is unable to withstand the stresses during operation. It is also not possible to move the bearing  116  along the shaft  114 , as the bearing  116  is held in its location by an outer retaining ring  210  and an inner retaining ring  212 . Therefore, a different but direct lube circuit is required to provide lubrication to the bearing  116 . The improved housing  102  described above is successful in providing a direct lube circuit with sufficient lubrication for the bearing  116 . 
     Turning to  FIG. 3 , a closer view of a portion of the housing  102  and flow path is shown. As described above, the housing  102  includes side wall  106  that is substantially vertical with respect to the inner wall  104  and surface  108  that is angularly disposed or sloped with respect to the side wall  106 . In at least one embodiment, the side wall  106  does not have to be entirely vertically-disposed with respect to the inner wall  104 . In fact, the side wall  106  can include protrusions, recesses, and the like. 
     The surface  108  includes edges  302 ,  304  which can assist with fluid flow. The edges  302 ,  304  can have an angular disposition such that fluid is directed towards the collection area  110  (see  FIG. 4 ) and collects behind the bearing  116 . The surface  108  has a circumference less than 180°. The edges  302 ,  304  are disposed with respect to axis A-A at angles θ 2 , θ 1 , respectively. Angles θ 2 , θ 1  can be substantially the same, or in other embodiments, the two angles can be different. For example, the angles θ 2 , θ 1  can be less than 90°. In one embodiment, both angles θ 2 , θ 1  are approximately 75°. Since θ 2 , θ 1  are less than 90°, the edges  302 ,  304  direct fluid from the side wall  106  and surface  108  to the collection  110 . 
     In addition, the side wall  106  is shown with an opening centrally defined therein (see  FIG. 1 ). As described above, the bearing pilot  120  can be assembled in the housing  102  such that a portion of the bearing pilot  120  passes through the opening. The side wall  106 , and in particular the front face  122 , defines a surface  214  which is disposed near the bottom portion of the housing  102 . The surface  214  is disposed on the opposite side of the side wall  106  from the collection area  110 . 
     Referring to the embodiment of  FIG. 4 , the variator  112  can function as a fluid source. In other embodiments, a pump or other device can function as a fluid source. During operation, the variator  112  dispenses fluid  400  in various directions. A portion of the fluid  400  is dispersed onto the inner wall  104  of the housing  102 . Another portion of the fluid  400  can be dispersed directly onto the side wall  106 . The portion of the fluid  400  that is dispersed onto the inner wall  104  can flow along the inner wall  104  until it is directed downwardly along the side wall  106 . Fluid  400  flows along the inner wall  104  and/or side wall  106  such that a sufficient amount of the fluid  400  reaches the angularly disposed surface  108 . At the intersection of the side wall  106  and surface  108 , the fluid  400  continues flowing along the surface  108 . Some of the fluid  400  reaches the top portion of the bearing  116  (as shown in  FIG. 4 ), whereas the remaining amount of fluid  400  flows past surface  108  and is received in the collection area  110 . As the fluid  400  is received in the collection area  110 , the fluid  400  is fluidly coupled to the bearing  116 . As such, the bearing  116  is sufficiently lubricated. 
     The above-described housing  102  therefore provides a direct fluid or lube path to the bearing  116 . Fluid  400  is dispersed from a fluid source onto a housing wall, e.g., inner wall  104  or side wall  106 . Gravity and the angular orientations of the housing walls allow a sufficient amount of fluid  400  to flow into contact with the bearing  116  and provide adequate lubrication. Advantageously, a lube path is not required to pass through holes or openings formed in a shaft. As a result, the transmission  100  can withstand higher torque and provide greater power to the vehicle. 
     While exemplary embodiments incorporating the principles of the present invention have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.