Patent Publication Number: US-11649884-B1

Title: Differential lubrication

Description:
INTRODUCTION 
     The present disclosure is directed to systems and methods for lubricating a differential for a vehicle, and more particularly, to systems and methods that lubricate an open differential. 
     SUMMARY 
     Example illustrations herein are directed to a side gear for a differential, e.g., an open differential. In at least some example approaches, a differential system includes one or more passages in a differential casing configured to draw in lubrication from a lubrication reservoir. The system includes one or more radial grooves of a differential side gear, where at least one of the radial grooves comprises an inner point where the lubrication enters the radial groove, and where the lubrication is ejected radially from the inner point to an outer point of the radial groove. In at least some example approaches, a side gear includes a first surface comprising a set of gears or protrusions configured to interface with differential gears of a differential. The protrusions may cover a perimeter edge of the first surface. The side gear may also include a second surface arranged to face opposite to the first surface. The second surface may include a plurality of radial grooves configured to draw in lubrication while the side gear rotates. 
     In at least some example approaches, a differential assembly includes a housing disposed partially in a lubrication reservoir, the housing enclosing a plurality of interfacing components configured to translate rotational motion of a pinion gear to rotational motion of a pair of axle shafts extending from the housing and permit different rotational speeds of the axle shafts. The plurality of interfacing components may include a pair of differential gears configured to translate rotational motion from the housing to the pair of axle shafts, and at least one side gear driving rotation of a first one of the axle shafts. The side gear may include a first surface comprising a set of gears or protrusions configured to interface with the differential gears, wherein the protrusions cover a perimeter edge of the first surface, and a second surface arranged to face opposite to the first surface. The second surface may include a plurality of radial grooves configured to draw in lubrication from the lubrication reservoir while the first side gear rotates. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
       The present disclosure, in accordance with one or more various embodiments, is described in detail with reference to the following figures. The drawings are provided for purposes of illustration only and merely depict typical or example embodiments. These drawings are provided to facilitate an understanding of the concepts disclosed herein and should not be considered limiting of the breadth, scope, or applicability of these concepts. It should be noted that for clarity and ease of illustration these drawings are not necessarily made to scale. The above and other objects and advantages of the disclosure may be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which: 
         FIGS.  1 A and  1 B  illustrates a pair of examples of differential assemblies with side gears having grooves for lubricating differential components, in accordance with some embodiments of the disclosure; 
         FIGS.  2 A and  2 B  illustrate a pair of views of an exemplary side gear with a plurality of grooves, in accordance with some embodiments of the disclosure; 
         FIGS.  3 A and  3 B  illustrate a pair of views of an exemplary side gear with a plurality of angled grooves, in accordance with some embodiments of the disclosure; 
         FIG.  4    illustrates an example of a differential assembly with a pair of separate side gears, in accordance with some embodiments of the disclosure; 
         FIG.  5    illustrates an example of a differential assembly with a pumping mechanism, in accordance with some embodiments of the disclosure; 
         FIG.  6    shows a schematic diagram of an illustrative vehicle system with a differential assembly incorporating a side gear configured to improve lubrication within the differential assembly, in accordance with some embodiments of the disclosure; and 
         FIG.  7    shows an illustrative vehicle system with a differential assembly incorporating a side gear configured to improve lubrication within the differential assembly, in accordance with some embodiments of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure, in accordance with one or more various embodiments, is described in detail with reference to the following figures. The drawings are provided for purposes of illustration only and merely depict typical or example embodiments. These drawings are provided to facilitate an understanding of the concepts disclosed herein and shall not be considered limiting of the breadth, scope, or applicability of these concepts. It should be noted that for clarity and ease of illustration these drawings are not necessarily made to scale. 
     Methods and systems are provided herein for lubricating internal interfaces of a differential assembly. 
     Current approaches for lubricating a differential may employ a static reservoir of lubrication such that the rotating portions of the differential will pass through the lubrication based on the level of lubrication available in the reservoir. This method is deficient because the lubrication is not uniformly distributed among the various moving and interfacing components as the different components of the differential rotate in response to different inputs into the system. Additionally, the distribution is affected by the static level of lubrication of the reservoir through which the components rotate. For example, if the static level of lubrication is below the inner most radial distance of one of the interfacing gears or center of the side gear, the lubrication may not reach that portion of the gear interface and the components will continue to operate without any lubrication, creating additional operational noise and increasing wear between components. Alternatively, filling the differential with additional lubricant increases overall drag of the differential and reduced powertrain efficiency. 
     Other approaches rely on forced lubrication to attempt to increase the distribution of lubrication among the interfaces of components within the differential. However, these approaches are also deficient because the addition of the pump or injector mechanism creates packaging issues for the differential assembly within a vehicle suspension environment. Moreover, pumps deliver lubricant to a single location, and thus only provide a single trajectory at which lubrication is introduced to interfaces between moving parts of the differential, creating non-uniform lubrication of the various components. To the extent differential components are consistently operating without lubrication, additional operating noise can manifest, and the parts may fatigue or fail before an expected lifetime has elapsed. 
     In view of the foregoing, some example systems and methods described herein lubricate a differential by incorporating passages into a differential case as well as a plurality of grooves into a rotating component of the differential, e.g., one or both side gears. A differential may include components such as housing that is rotated by a pinion, e.g., by a side gear fixed to the housing. The housing may contain one or more passages which serve as openings to enable lubricant to be pumped from a static reservoir of lubrication into the interfaces between internal components of a differential. As the side gears rotate in the disconnected state, they create a negative pressure at the inner opening of the passageways, which draws in the lubrication from the static reservoir. Within the differential housing, there may also be at least one drive shaft, axle shaft, or half shaft for translating rotational motion from the powertrain received at the differential to the road wheels. Side gears may be supported within the housing for transmitting rotational motion from the side gear/housing to the axle shafts. Differential gears may be supported on a spindle supported at either end by the housing. 
     Accordingly, rotation of the housing causes rotation of the spindle, with the differential gears imparting rotational motion to the side gears. The differential may be an open differential, such that different rotating speeds of the axle shafts are permitted, e.g., to accommodate a vehicle turning. The side gear(s) include an interface side having protrusions or gears which mate with the differential gears, and a reverse face which may include a hub. The reverse or opposite face may have a surface with a plurality of grooves formed therein, which may be positioned such that they extend from an outer diameter of the side gear to or adjacent a center of the side gear. In some example approaches, the grooves may have a length sufficient to reach a static lubricant level within the differential. Thus, as the side gear rotates, each groove enters the lubricant that has accumulated at the bottom of the differential housing, with lubricant being drawn into the grooves from the static lubricant level and distributed throughout the interfacing components of the differential assembly. In other example approaches, the static level of lubricant may be relatively lower, with lubricant being pumped or distributed by way of passages in the differential to the grooves in the side gear. In one example, the channels in the housing may be positioned such that an inner opening of the channel aligns with a radially outer end of the grooves in the side gear. In this example, any pumping of the lubrication may result in the lubrication being pooled in the bottom of the housing for the radially outer edge of the side gear to rotate thorough. In another example, the channels in the housing may be positioned such that an inner opening of the channel aligns with a radially inner end of the grooves of the side gear. In this example, any pumping of the lubrication results in a direct translation of the lubrication from the reservoir through the channels to the grooves in the side gear such that the lubrication does not pool in the housing as a result of the pumping and instead the lubrication is readily distributed by the rotation of the side gears. 
     These example techniques advantageously do not rely solely on a static level of lubrication, as in previous approaches noted above. Instead, a side gear or hub has a plurality of grooves in its face that dip into a static level of lubrication, and through the rotation of the hub, creates a pumping action which draws lubrication into each respective groove through centripetal force and then distributes the lubricant throughout the components of the differential by centrifugal force. Channel(s) in the differential case may serve as continuous feeds of lubrication, as the lubrication previously accrued within the differential housing is distributed among the components. Thus, while a static lubrication level may allow at least a portion of the hub to become at least partially saturated with lubrication, the combination of the channels in the differential case and the grooves on the side gear(s) enable a greater distribution of lubrication throughout the various components of the differential. 
     Additionally, while in some example approaches a pump may be employed to further assist with lubrication of differential components, the example approaches herein do not rely solely on an external mechanism such as a pump to improve the distribution of lubrication throughout the differential case. Rather, the side gear grooves and/or channels in the differential case improve lubrication using existing components of the differential assembly. More specifically, the side gear grooves in various examples below may reach into the volume of lubricant in the reservoir, and the structure of the grooves draws lubricant into the grooves and, as a result of rotation of the side gear, distributes lubricant about the housing of the differential assembly, thereby providing more consistent lubrication of differential assembly components. 
     In some embodiments, the radial grooves extend from a diameter proximate a central most point on the surface of the side gear to an outer diameter. In some embodiments, the grooves are arranged to be along a straight radial line, while in other example approaches one or more of the grooves are angled relative to a radial direction of the side gear. The angle of the grooves may correspond to target lubrication rate (e.g., 0.15 Liters per minute) such that the target volume of lubrication is distributed about the differential housing at the target lubrication rate. The angle generally allows for a longer length of the grooves which may enable more of the grooves to enter the lubrication reservoir, thereby distributing a greater volume of lubricant throughout the housing for each pass of the groove and/or rotation of the side gear. Accordingly, the geometry of the grooves, the positioning of the grooves, and rotational speed(s) or range of speeds of the side gears may each influence a volume of lubricant distributed via the grooves. 
     In some embodiments, at least a portion of the side gear is positioned below the surface of the static reservoir of lubrication. Accordingly, at least a portion of each of the grooves as the side gear rotates is submerged below the surface of the static reservoir of lubrication. The spacing and number of grooves may be determined such that at least one of each of the grooves is submerged in the lubrication reservoir at a time to enable continuous distribution of lubrication at the side gear rotates. The spacing and number of grooves may also be determined such that the volume of the grooves paired with the rotational rate of the side gear enables the differential assembly to receive lubricant at a flow rate comparable to a target rate. 
     In some embodiments, each of the grooves has at least one opening at one end of the groove. The opening enables the ingress of lubrication into the groove from a lubrication reservoir such that it can be distributed by the rotation of the side gear. The opening also enables the egress of lubrication out of the groove such that it is distributed throughout the differential assembly. 
     In some embodiments, each of the side gears of a differential assembly include groove feature(s) similar or identical to those of the first side gear, such that a second portion of the differential assembly receives improved lubrication. 
     In some embodiments, at least a pair of channels are positioned in a lower portion of the differential assembly housing, such that the rotation of the side gear draws in lubrication from the static lubrication reservoir. 
     In some embodiments, a second channel is positioned in an upper portion of the differential assembly and includes a pump or other mechanism for forcing lubrication through the channel(s) of the housing and/or within the differential. The pump may be configured to draw lubrication from the static lubrication reservoir and expel lubrication into the differential assembly from a vertically upper position, thereby allowing lubricant to be communicated over substantially all interfacing surfaces within the housing. The combination of the pump with the grooves in the side gear further enhances consistent distribution of lubrication throughout the differential assembly. 
     In some embodiments, the grooves are embedded in a hub separate from the side gear and positioned proximate to the side gear. The hub may be arranged to rotate at the same rate as the side gear. 
     Turning now to  FIGS.  1 A and  1     i , a pair of exemplary example differential assemblies  100 A and  100 B illustrated, respectively, with each having a side gear configured to distribute lubricant from a static lubrication reservoir, in accordance with some embodiments of the disclosure. It should be noted that differential assembly  100 A, differential assembly  100 B or any component thereof may be integrated into any of the side gears shown in  FIGS.  2 A and  2 B , the side gears shown in  FIGS.  3 A and  3 B , differential assembly  400  of  FIG.  4   , differential assembly  500  of  FIG.  5   , vehicle system  600  of  FIG.  6   , or vehicle  700  of  FIG.  7   . 
     Differential assemblies  100 A and  100 B are encased by housing  102 . Housing  102  provides an enclosure for a plurality of interfacing components that are part of differential assemblies  100 A and  100 B. For example, the interfacing components may include at least one side gear, a collection of spider gears, a pair of axle shafts with side gears positioned at the ends of the axle shafts, and a pinion gear. The pinion gear may be positioned to translate rotational motion from a transmission assembly into the differential assembly. The pinion gear may interface with a plurality of protrusions of the side gear to translate rotational motion to the spider gears. The spider gears may be positioned to interface with the ring and gear translate rotational motion to wheel assemblies affixed to the axle shafts. 
     Side gear  104  is positioned within housing  102 . The edge of side gear  104  is positioned such as it rotates, lubrication from a static lubrication reservoir, in which housing  102  resides, is drawn into radial grooves  108 . Radial grooves  108  may be positioned in one side gear  104  or both side gears  104  of the differential assemblies  100 A,  100 B. The radial grooves  108  are structured such that as side gear  104  rotates, lubrication is drawn into each respective groove. Lubrication channels  110  enable the egress of lubrication from the static lubrication reservoir into housing  102  such that each of radial grooves  108  takes in a portion of lubrication and distributes the lubrication through the internal components of encased within housing  102 . 
     The lubrication level may be represented by lubrication level  106 A or  106 B, depending on desired performance parameters for each of differential assemblies  100 A and  100 B, respectively. Lubrication reservoir  106 A is at a depth such that at least a portion of radial grooves  108  is submerged below the surface of lubrication reservoir  106 A. This enables a continuous submersion of side gear  104  in lubrication reservoir  106 A to ensure a continuous distribution of lubrication within housing  102 . By contrast, lubrication reservoir  106 B is at a depth such that radial grooves  108  are not submerged below the surface of lubrication reservoir  106 B. In some embodiments, lubrication reservoir  106 B may be preferred as the lower lubrication level reduces overall friction within the unit. As a result, side gear  104  is free to accelerate and rotate at faster rates due to the reduction in drag. As side gear  104  rotates, lubrication from lubrication reservoir  106 B pumped to the grooves  108  via lubrication channels  110 , which each have an end submerged below the surface of lubrication reservoir  106 B. The rotation of side gear  104  may create a pressure differential between a first end of each of lubrication channels  110  which is open to the internal structures encased by housing  102  and the second end of each of lubrication channels  110  which is submerged below the surface of lubrication reservoir  106 B. The pressure differential may cause the ingress of lubrication from lubrication reservoir  106 B into housing  102  such that the lubrication is fed into radial grooves and distributed throughout the interfaces of differential assembly  100 B. 
     In one example, lubrication channels  110  may be positioned such that an inner opening of each of lubrication channels  110  aligns with a radially outer end of radial grooves  108 . In this example, any pumping of the lubrication may result in the lubrication being pooled in the bottom of the housing for the radially outer edge of the side gear to rotate thorough. In another example, lubrication channels  110  in the housing may be positioned such that an inner opening of each of lubrications channels  110  aligns with a radially inner end of the radial grooves  108  (e.g., as shown in  FIGS.  1 A and  1   ). In this example, any pumping of the lubrication results in a direct translation of the lubrication from the reservoir through lubrication channels  110  to radial grooves  108  such that the lubrication does not pool in the housing as a result of the pumping and instead the lubrication is readily distributed by the rotation of the side gears. 
       FIGS.  2 A and  2 B  illustrate an exemplary side gear  200 , each with a plurality of grooves, in accordance with some embodiments of the disclosure. It should be noted that side gear  200  or any component thereof may be integrated into any of the differential assemblies of  FIG.  1   , the side gears of  FIGS.  3 A and  3 B , differential assembly  400  of  FIG.  4   , differential assembly  500  of  FIG.  5   , vehicle system  600  of  FIG.  6   , or vehicle  700  of  FIG.  7   . 
     Side gear  200 , as shown in  FIGS.  2 A and  2 B , includes surface  202  arranged to face away from the center portion of a differential assembly (e.g., differential assembly  100  of  FIG.  1   ). An opposite face of the side gear  200  may include protrusions or gears configured to mate with other gears of a differential. Central opening  204  is an opening through which an axle shaft protrudes to create an interface with other internal rotating components within the differential assembly (e.g., interface with spider gears). Radial grooves  206  are grooves embedded in surface  202  and, in some examples, are positioned such that at least a portion of each of radial grooves  206  reach below lubrication level  208  as surface  202  rotates about a central axis. Alternatively, a lubrication level may be relatively lower, as noted above. Each of radial grooves  206  are arranged such that both a radially inward most point and a radially outward most point are radially aligned without an angular offset. 
     Side gear  200  is shown as a perspective view of a side gear with radial grooves  206  in  FIG.  2 B . As shown in  FIG.  2 B , each of radial grooves  206  of the side gear  200  comprise a depth that is below surface  202 , but do not create an opening through the side gear  200 . Additionally, each of radial grooves  206  have a radially inner end which does not contact a structure which borders central opening  204 , e.g., a hub  207  of the side gear  200 . The depth, length, and width of each of radial grooves may be determined based on factors such as rotational speed of side gear  200 , desired lubrication levels within a differential assembly that utilizes side gear  200 , and the number of grooves required to maintain an idea distribution of lubrication. 
     Turning now to  FIGS.  3 A and  3 B , an exemplary side gear  300  is illustrated with a plurality of angled grooves, in accordance with some embodiments of the disclosure. It should be noted that side gear  300  or any component thereof may be integrated into any of the differential assemblies of  FIG.  1   , the side gears of  FIGS.  2 A and  2 B , differential assembly  400  of  FIG.  4   , differential assembly  500  of  FIG.  5   , vehicle system  600  of  FIG.  6   , or vehicle  700  of  FIG.  7   . 
     Side gear  300 , as shown in  FIGS.  3 A and  3 B , includes surface  302  arranged to face away from the center portion of a differential assembly (e.g., differential assembly  100  of  FIG.  1   ). Central opening  304  is an opening through which an axle shaft with a side gear protrudes to create an interface with other internal rotating components within the differential assembly (e.g., interface with spider gears). Radial grooves  306  are grooves embedded in surface  302  and are positioned such that at least a portion of each of radial grooves  306  reach below lubrication level  308  as surface  302  rotates about a central axis. Alternatively, a lubrication level may be relatively lower, as noted above. Each of radial grooves  306  are arranged such that a radially inward most point and a radially outward most point are not radially aligned. Angle α of each of radial grooves  306  relative to a radial direction of the side gear  300  is based on a rotational speed corresponding to when components of the different will be disengaged such that lubrication can be circulated throughout the differential without translating rotational motion to wheel assemblies. 
     Angle α also corresponds to an ideal lubrication rate such that the lubrication drawn into the collection of grooves can adequately enable lubrication of all interfaces within the differential assembly. In one example, the channels in the housing may be positioned such that an inner opening of the channel aligns with a radially outer end of radial grooves  306 , as shown in  FIG.  3 A . In this example, any pumping of the lubrication may result in the lubrication being pooled in the bottom of the housing for the radially outer edge of side gear  300  to rotate thorough. In another example, the channels in the housing may be positioned such that an inner opening of the channel aligns with a radially inner end of radial grooves  306  of the side gear (e.g., as shown in  FIGS.  1 A and  1     i ). In this example, any pumping of the lubrication results in a direct translation of the lubrication from the reservoir through the channels to radial grooves  306  in the side gear such that the lubrication does not pool in the housing as a result of the pumping and instead the lubrication is readily distributed by the rotation of the side gears. 
     Side gear  300  is illustrated in a perspective view of a side gear with radial grooves  306  in  FIG.  3 B . As shown in  FIG.  3 B , each of radial grooves  306  comprise a depth that is below surface  302 , but do not create an opening in the material comprising side gear  300 . Additionally, each of radial grooves  306  have a radially inner end which does not contact a structure which borders central opening  304 , e.g., hub  307 . The depth, length, and width of each of radial grooves may be determined based on factors such as rotational speed of side gear  300 , desired lubrication levels within a differential assembly that utilizes side gear  300 , and the number of grooves required to maintain an idea distribution of lubrication. Additionally, angle α may be considered in the length, width, depth, and number of radial grooves  306  as angle α may increase the overall length of radial grooves  306  relative to radial grooves  206  from  FIGS.  2 A and  2 B . 
     Angle α may also correspond to an ideal lubrication rate such that the lubrication drawn into the collection of grooves can adequately enable lubrication of all interfaces within the differential assembly. For example, a greater value corresponding to angle α will tend to create a greater lubrication rate by “pumping” a greater amount of lubricant from below the lubrication level  308  for a given rotational speed of side gears  300 A and  300 B. More specifically, the greater value corresponding to angle α enables a generally longer embodiment of grooves  306  compared with a groove that is aligned with a radial direction of the surface  302  (e.g., as shown by the grooves of side gears  200 A and  200 B compared to the grooves of side gears  300 A and  300 B). Accordingly, the angled grooves  306  proportionally increase an amount of lubricant volume contained by the grooves  306  and/or that is communicated throughout a differential assembly. 
     In some embodiments, angle α is an acute angle (e.g., less than 90 degrees and not perpendicular) and does not exceed a value such that grooves  306  rotate parallel to the outer diameter of side gears  300 A and  300 B. If angle α were to position each of grooves  306  such that they create circular grooves on the surface of ring gears  300 A and  300 B, then there would be no edge of grooves  306  to rotate through lubrication level  308  and draw in lubrication to distribute about the differential assembly comprising side gears  300 A and  300 B. 
     In one example, the channels in the housing may be positioned such that an inner opening of the channel aligns with a radially outer end of radial groves  306  (e.g., as shown in  FIG.  3 A ). In this example, any pumping of the lubrication may result in the lubrication being pooled in the bottom of the housing for the radially outer edge of the side gear to rotate thorough. In another example, the channels in the housing may be positioned such that an inner opening of the channel aligns with a radially inner end of radial grooves  306 . In this example, any pumping of the lubrication results in a direct translation of the lubrication from the reservoir through the channels to radial grooves  306  such that the lubrication does not pool in the housing as a result of the pumping and instead the lubrication is readily distributed by the rotation of the side gears. 
     In some embodiments, the shape of radial grooves  306  is configured for additional oil flow to achieve target lubrication rates and target cooling rates. In some embodiments, the shape of radial grooves  306  comprises a profile with at least one rounded side. Rounded grooves may generally prevent sharp corners which might otherwise act as stress-concentrators. Additionally, rounded grooves may also be forged into the gear, improving a material grain-flow around the groove and improving strength of the component in which the groove is formed. In some embodiments, a particular use case of radial grooves  306  may determine an optimum groove geometry. For example, use cases driving groove geometry may include a target operating temperature and/or operating temperature range, a target operating rotational speed and/or operating rotational speed range, different lubrication or oil viscosity and/or other properties related to lubrication flow, and the expected duty cycle of a differential assembly comprising radial grooves  306 . Generally larger groove cross-sectional areas may allow more oil flow for better lubrication and cooling, while limiting flow by way of a relatively smaller cross-sectional area may improve overall efficiency (i.e., less viscous losses). In some embodiments, the profile of the cross-section of each of radial grooves  306  may be the same for the entire groove opening. In some embodiments, the profile of the cross-section of each of radial grooves may be varying along each groove opening. For example, a decreasing cross-section could be used to accelerate oil flow along the groove, or the majority of the groove could be over-sized and may narrow at a radially outboard portion exit to reduce losses due to turbulence or friction. 
       FIG.  4    illustrates exemplary differential assembly  400  with a pair of separate side gears, in accordance with some embodiments of the disclosure. It should be noted that differential assembly  400  may include any of the components described above, e.g., of differential assembly  100  of  FIG.  1   , side gear  200  of  FIGS.  2 A and  2 B , or side gear  300  of  FIGS.  3 A and  3 B . Differential assembly  400  or any component thereof may also be integrated into any of differential assembly  500  of  FIG.  5   , vehicle system  600  of  FIG.  6   , or vehicle  700  of  FIG.  7   . 
     Differential assembly  400  is encased by housing  402 . Housing  402  generally provides an enclosure for a plurality of interfacing components that are part of differential assembly  400 . The differential assembly  400  may be configured to transmit rotational motion from a pinion gear (not shown in  FIG.  4   ) being driven by an electric motor, transmission, or the like to a pair of side gears  404 . The side gears  404  each drive a corresponding axle shaft  414 . Differential assembly  400  generally facilitates isolated translation of rotational motion to a pair of wheel assemblies associated with each of the axle shafts  414 . 
     The gears  404  are positioned within the housing  402 . The edge of the gears  404  are positioned such that they rotate through a surface of lubrication level  406 , which is a level of lubrication as created by a static lubrication reservoir in which housing  402  resides. Radial grooves  408  may be positioned on one or, as shown in  FIG.  4   , both of the side gears  404 . The grooves  408  are drawn through lubrication level  406  as side gears  404  rotate within housing  402 . Lubrication channels  410  may generally facilitate delivery of lubricant from the static lubrication reservoir into housing  402 , such that each of radial grooves  408  takes in lubricant and distributes the lubrication through the internal components of encased within housing  402 . In one example, the channels in the housing may be positioned such that an inner opening of the channel aligns with a radially outer end of the grooves in the side gear. In this example, any pumping of the lubrication may result in the lubrication being pooled in the bottom of the housing for the radially outer edge of the side gear to rotate thorough. In another example, the channels in the housing may be positioned such that an inner opening of the channel aligns with a radially inner end of the grooves of the side gear. In this example, any pumping of the lubrication results in a direct translation of the lubrication from the reservoir through the channels to the grooves in the side gear such that the lubrication does not pool in the housing as a result of the pumping and instead the lubrication is readily distributed by the rotation of the side gears. 
       FIG.  5    illustrates exemplary differential assembly  500  with a pump, in accordance with some embodiments of the disclosure. It should be noted that differential assembly  500  or any component thereof may be integrated into any of differential assembly  100  of  FIG.  1   , side gear  200  of  FIGS.  2 A and  2 B , side gear  300  of  FIGS.  3 A and  3 B , differential assembly  400  of  FIG.  4   , vehicle system  600  of  FIG.  6   , or vehicle  700  of  FIG.  7   . 
     Differential assembly  500  includes a housing  502 . Housing  502  provides an enclosure for a plurality of interfacing components that are part of differential assembly  500 . For example, the housing  502  may be fixed for rotation with a pair of side gears driven by at least one pinion receiving rotational power from an electric motor, transmission, etc. (not shown in  FIG.  5   ). The housing  502  may drive rotation of a pair of side gears  504  and allow for differential speeds of rotation by way of differential gears  505  supported on a spindle  503 . 
     The side gears  504  are positioned within housing  502 . The edge of side gears  504  may each be positioned such that a lower portion thereof rotates through the surface of lubrication level  506 , which may be a level of lubrication created by a static lubrication reservoir within the housing  502 . Radial grooves  508  are positioned on side gear  504  and are drawn through lubrication level  506  as side gears  504  rotates within housing  502 . The radial grooves  508  may be radially aligned, e.g., as described above in  FIGS.  2 A and/or  2 B , or may be angled as illustrated in  FIGS.  3 A and/or  3 B . Lubrication channels  510  facilitate delivery of lubricant from the static lubrication reservoir  506  into housing  502 , such that each of radial grooves  508  takes in lubricant and distributes the lubrication through the internal components of encased within housing  502  as a result of the rotation of the side gear(s)  504 . The side gears  504  each drive a corresponding axle shaft  514 . Differential assembly  500  generally facilitates isolated translation of rotational motion to a pair of wheel assemblies associated with each of the axle shafts  514 . 
     The differential assembly  500  may employ a pump for further enhancing distribution of lubricant within the differential assembly  500 . For example, lubrication distribution line  512  reaches below lubrication level  506  and channels lubricant into pump  516 . Pump  516  may be positioned in an upper portion of housing  502  as shown in  FIG.  5   , and thus may be configured to pump lubricant from the reservoir  506  into housing  502  from an elevated position. Pump  516  may in some embodiments pump lubricant directly into at least one of radial grooves  508 . 
       FIG.  6    shows a schematic diagram of illustrative vehicle system  600  with a differential assembly configured to improve lubrication within the differential assembly, in accordance with some embodiments of the disclosure. It should be noted that vehicle  600  or any component thereof may be integrated into any of differential assembly  100  of  FIG.  1   , side gear  200  of  FIGS.  2 A and  2 B , side gear  300  of  FIGS.  3 A and  3 B , differential assembly  400  of  FIG.  4   , and differential assembly  500  of  FIG.  5   . 
     Vehicle  602  includes vehicle body  604  and vehicle powertrain assembly  606 . The powertrain assembly  606  may include one or more electric motors, an internal combustion (IC) engine, or any other engine for providing rotational power to provide motive force for vehicle  602 . Accordingly, the vehicle  602  may be a battery-electric vehicle (BEV), a hybrid vehicle employing a combination of electric motor(s) with an IC engine, or a vehicle relying solely upon an IC engine for motive power. Within vehicle powertrain assembly  606 , there is a static lubrication reservoir  608 . Static lubrication reservoir  608  is a source of lubrication for differential housing  610  and the interfacing components therein. A differential housing  610  may be rotated by a pinion gear receiving rotational power from an electric motor, engine, transmission, etc. The differential housing  610  may in turn drive axle shafts  614 A and  614 B, e.g., by way of one or more differential gear(s)  612  that rotate with the housing  610  and in turn rotate side gears  616 A and/or  616 B. Side gears  616 A and  616 B may be represented by any of the side gears described above in  FIGS.  1 - 5   . Additionally, in some embodiments differential housing  610  interfaces with a pump  618 . The pump  618  may in some embodiments correspond to pump  516  of  FIG.  5   . Pump  618  may represent any form of mechanism that, when coupled with differential housing  610 , enables additional forced lubrication of the components interfacing within differential housing  610 . 
     Turning now to  FIG.  7   , an illustrative vehicle system  700  is shown having a differential assembly incorporating side gear(s) configured to improve lubrication within the differential assembly, in accordance with some embodiments of the disclosure. It should be noted that vehicle  700  or any component thereof may be integrated into any of differential assembly  100  of  FIG.  1   , side gear  200  of  FIGS.  2 A and  2 B , side gear  300  of  FIGS.  3 A and  3 B , differential assembly  400  of  FIG.  4   , differential assembly  500  of  FIG.  5   , and vehicle system  600  of  FIG.  6   . 
     Vehicle system  700  includes vehicle support structure  702 . As illustrated, vehicle support structure  702  is a “skateboard” structure, to which a vehicle passenger compartment, cargo area (not shown), etc. may be mounted. Mounted in vehicle support structure  702  are one or more electric motors  704 , battery packs  706 , suspension  708 , and fan assembly  710 . Motor  704  is powered by battery packs  706  and generally provides rotational motion via differential  712  to vehicle wheels. Vehicle system  700  may include elements of vehicle system  600  of  FIG.  6   , as well as any of the other elements depicted in  FIGS.  1 - 5   , or a combination thereof. Differential  712  may include the elements of differential assembly  100  of  FIG.  1   , differential assembly  400  of  FIG.  4   , or any combination of elements as depicted in  FIG.  2 A,  2 B,  3 A,  3 B,  5   , or  6 . 
     Differential  712  may be include a housing  714 . Housing  714  provides an enclosure for a plurality of interfacing components that are part of differential  712 . For example, as discussed above a side gear fixed for rotation with the housing  714  may be driven by a pinion gear (not shown in  FIG.  7   ), which in turn rotates a spindle having a pair of differential gears  724 . The differential gears in turn drive side gears  716  of the differential assembly  712 , and allow for different rotational speeds of corresponding axle shafts, for example in the manner described above. 
     Side gears  716  may each be positioned within housing  714 . The edge of side gears  716  may be positioned such that they rotate through a surface of lubrication level  718  which is a level of lubrication as created by a static lubrication reservoir in which housing  714  resides. Radial grooves  720  may be positioned on one or both side gear(s)  716  and are drawn through lubrication level  718  as side gear  716  rotates within housing  714 . Lubrication channels  722  may also be provided, which may introduce lubricant from the static lubrication reservoir  718  into housing  714  such that each of radial grooves  720  takes lubricant and distributes the lubricant throughout the internal components of encased within housing  714 . In some embodiments, radial grooves  720  may be embedded in a hub separate from side gear  716  that is mechanically secured to side gear  716  such that the hub rotates with side gear  716 . 
     The systems and processes discussed above are intended to be illustrative and not limiting. One skilled in the art would appreciate that the actions of the processes discussed herein may be omitted, modified, combined, and/or rearranged, and any additional actions may be performed without departing from the scope of the invention. More generally, the above disclosure is meant to be exemplary and not limiting. Only the claims that follow are meant to set bounds as to what the present disclosure includes. Furthermore, it should be noted that the features and limitations described in any one embodiment may be applied to any other embodiment herein, and flowcharts or examples relating to one embodiment may be combined with any other embodiment in a suitable manner, done in different orders, or done in parallel. In addition, the systems and methods described herein may be performed in real time. It should also be noted that the systems and/or methods described above may be applied to, or used in accordance with, other systems and/or methods. 
     While some portions of this disclosure may refer to “convention” or examples, any such reference is merely to provide context to the instant disclosure and does not form any admission as to what constitutes the state of the art.