Patent Publication Number: US-2023150458-A1

Title: Brake assembly

Description:
FIELD 
     The subject matter of the embodiments described herein relates generally to an axle assembly for a vehicle and, more particularly, to a brake assembly of the axle assembly for the vehicle. 
     BACKGROUND 
     A vehicle including an axle assembly with a brake assembly is known in the art. The brake assembly may comprise a multi-disc brake or clutch designed to generate a constant braking or coupling force. Hydraulically actuated disc brakes are the most commonly used form of brake for motor vehicles due to their stable performance at higher speeds and resistance to brake fade. 
     However, the disc brakes are subjected to extreme conditions and wear each time the vehicle is stopped. Accordingly, the brake assembly, including but not limited to the disc brakes, requires continued maintenance and repair to maintain performance of the axle assembly. Typically, an installation of the brake assembly into the axle assembly during production or the repair of the brake assembly is difficult, particularly when parts need to be pressed into an arm of the axle assembly using specialized equipment. Some brake assemblies require an expensive hydraulic pressing system to compress spring applied hydraulic release (SAHR) springs so the service brake assemblies can be installed and secured. 
     It would be desirable to produce a brake assembly for an axle assembly that improves manufacturability and quality of the brake assembly while minimizing cost and complexity thereof. 
     SUMMARY 
     In concordance and agreement with the present disclosure, a brake assembly for an axle assembly that improves manufacturability and quality of the brake assembly while minimizing a cost and complexity thereof, has surprisingly been discovered. 
     In one embodiment, a brake assembly for an axle assembly, comprises: a brake mechanism including a plurality of brake discs; at least one biasing mechanism including at least one biasing element disposed adjacent the brake mechanism, wherein the at least one biasing element is pre-compressed; and a housing circumferentially enclosing at least a portion of the brake mechanism and at least a portion of the at least one biasing mechanism, wherein the housing is configured to mate with an axle housing of the axle assembly. 
     As aspects of certain embodiments, the brake mechanism is an interchangeable brake mechanism, and wherein a profile of the housing is configured to receive the interchangeable brake mechanism. 
     As aspects of certain embodiments, a profile of the housing is configured to receive differing numbers of the brake discs. 
     As aspects of certain embodiments, the brake assembly further comprises an end plate configured to be coupled to the housing of the brake assembly. 
     As aspects of certain embodiments, the end plate is configured to be coupled to the axle housing of the axle assembly. 
     As aspects of certain embodiments, an interior cavity of the housing is divided into a first chamber and a second chamber by a web portion. 
     As aspects of certain embodiments, the brake assembly further comprises a first piston disposed in a first chamber of the housing and a second piston disposed in a second chamber of the housing. 
     As aspects of certain embodiments, an activation of the first piston causes an activation of the brake assembly. 
     As aspects of certain embodiments, an activation of the second piston causes the at least one biasing element of the biasing mechanism to move to a compressed state. 
     As aspects of certain embodiments, a deactivation of the second piston results in the at least one biasing element of the biasing mechanism to move to an expanded state. 
     As aspects of certain embodiments, the biasing mechanism further includes a positioning element configured to maintain a position of the at least one biasing element, and wherein a portion of the positioning element surrounds an outer circumferential surface of the at least one biasing element. 
     As aspects of certain embodiments, the biasing mechanism further includes a retainer configured to maintain a position of the positioning element. 
     In another embodiment, an axle assembly, comprises: an axle housing; and a brake assembly coupled to the axle housing, the brake assembly comprises: a housing having a first chamber and a second chamber; a brake mechanism disposed in the first chamber; a first piston disposed in the first chamber, wherein the first piston is configured to selectively activate the brake mechanism; and a second piston disposed in the second chamber adjacent a biasing mechanism having at least one biasing element, wherein the second piston is configured to selectively activate the brake mechanism. 
     As aspects of certain embodiments, the brake assembly is removably received in and releasably coupled to an end of the axle housing. 
     As aspects of certain embodiments, the brake assembly is a cartridge style brake assembly that is preassembled prior to installation into the axle assembly. 
     As aspects of certain embodiments, the at least one biasing element is pre-compressed. 
     As aspects of certain embodiments, the brake assembly further includes a biasing mechanism disposed adjacent the brake mechanism in the first chamber. 
     As aspects of certain embodiments, at least one of the first chamber and second chamber includes an activation cavity in fluid communication with a source of pressurized fluid. 
     In yet another embodiment, an axle assembly, comprises: an axle housing configured to receive an interchangeable brake assembly, wherein the interchangeable brake assembly comprises: a housing having at least one chamber formed therein; a brake mechanism disposed in the at least one chamber; and at least one piston disposed in the at least one chamber, wherein the at least one piston is configured to selectively activate the brake mechanism. 
     As aspects of certain embodiments, the brake mechanism is an interchangeable brake mechanism. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above, as well as other objects and advantages of the subject matter of the embodiments described herein, will become readily apparent to those skilled in the art from a reading of the following detailed description of the embodiments when considered in the light of the accompanying drawings in which: 
         FIG.  1    is a fragmentary cross-sectional view of a portion of an axle assembly including a wheel assembly and a brake assembly according to an embodiment of the subject disclosure; 
         FIG.  2    is a side perspective view, in section, of the brake assembly of  FIG.  1   ; 
         FIG.  3    is a fragmentary side elevational view of the axle assembly shown in  FIG.  1   , wherein the wheel assembly has been removed; 
         FIG.  4    is a fragmentary cross-sectional view of a portion of an axle housing of the axle assembly shown in  FIG.  1   ; 
         FIG.  5    is a cross-sectional view of the brake assembly of  FIG.  1 - 3   , wherein the brake assembly includes three brake discs and four separator plates; 
         FIG.  6    is a cross-sectional view of the brake assembly of  FIG.  1 - 3   , wherein the brake assembly includes two brake discs and three separator plates; and 
         FIG.  7    is a fragmentary cross-sectional view of a portion of an axle assembly including a brake assembly according to another embodiment of the subject disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description and appended drawings describe and illustrate various exemplary embodiments. The description and drawings serve to enable one skilled in the art to make and use the embodiments, and are not intended to limit the scope of the embodiments in any manner. 
     It is to be understood that the presently disclosed subject matter may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific assemblies and systems illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined herein. Hence, specific dimensions, directions or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless expressly stated otherwise. Also, although they may not be, like elements in various embodiments described herein may be commonly referred to with like reference numerals within this section of the application. 
       FIG.  1    shows a portion of an axle assembly  10  for a motor vehicle (not depicted) according to an embodiment of the presently disclosed subject matter. The vehicle may include a chassis or frame (not depicted) configured to support a pair of the axle assemblies  10 . Each of the axle assemblies  10  may be configured to support a wheel (not depicted). It should be appreciated that at least one of the axle assemblies  10  may include one or more mechanisms (not depicted) for steering one or both of the axle assemblies  10 . The vehicle may include a prime mover (not depicted) such as an internal combustion engine or an electric motor, for example, configure to power the vehicle and/or at least one of the axle assemblies  10 . It is understood that the axle assemblies  10  may be any type of axle assembly as desired. 
     As illustrated, the axle assembly  10  may include an axle housing  12  having a brake assembly  14  at least partially disposed therein and a wheel assembly  29  coupled thereto. In certain embodiments, the brake assembly  14  is removably received in and releasably coupled to an end  13  of the axle housing  12  to allow the brake assembly  14  to be repaired and/or replaced. It should be appreciated that the brake assembly  14  may be coupled to the axle housing  12  by any method as desired such as by mechanical fasteners, for example. In certain embodiments, the brake assembly  14  may utilize pressurized fluid from a fluid source (not depicted) to actuate and/or de-actuate the brake assembly  14 . A pump (not depicted) may be employed to cause the pressurized fluid from the fluid source to flow through at least one conduit (not depicted) to the braking assembly  14 . As best seen in  FIG.  4   , the end  15  of the axle housing  12  may include a first port  15 , a second port  17 , and a third port  19 . The ports  15 ,  17 ,  19  may be in fluid communication with the fluid source via the at least one conduit. In certain embodiments, each of the ports  15 ,  17  is an input port permitting a flow of the pressurized fluid from the fluid source into the axle housing  12  and the port  19  is a drain or output port permitting a flow of a depressurized fluid from the axle housing  12  back to the fluid source. Each of the ports  15 ,  17 ,  19  may further include a respective valve  2 ,  4 ,  6  to control the flow of the pressurized fluid to the brake assembly  14  and/or the flow of the depressurized fluid from the brake assembly  14 . 
       FIG.  2    shows a first embodiment of the brake assembly  14 . The brake assembly  14  may be configured as a cartridge style brake assembly that may be pre-assembled prior to installation into the axle housing  12 . The cartridge style brake assembly  14  permits installation to be simplified and circumvents potential undesirable effects of installing under high pressure conditions and a need for specialized equipment by an end user. The brake assembly  14  allows a manufacturer thereof to control an assembly process. Additionally, the brake assembly  14  may be an interchangeable brake assembly  14  at least partially received in the axle housing  12 . In certain embodiments, the axle housing  12  may be a universal axle housing  12  having a profile configured to receive different configurations of the interchangeable brake assembly  14 . 
     The brake assembly  14  may include an annular housing  16  and an end plate  18  configured to be coupled to the axle housing  12 . Various methods may be employed to couple the end plate  18  to the annular housing  16  such as mechanical fasteners  20 , for example. In certain embodiments, the annular housing  16  of the brake assembly  14  may be received in a cavity  21  formed in the axle housing  12 . The end plate  18  may be secured to the axle housing  12  by a plurality of mechanical fasteners  22  to militate against an axial movement of the brake assembly  14  within the axle housing  12 . It should be appreciated that the end plate  18  may be coupled to the axle housing  12  by any method as desired. As illustrated, the mechanical fasteners  22  may be received through bores  23  formed in an annular array of spaced apart ears  24  radially extending from the end plate  18 . Although the end plate  18  shown includes four of the ears  24 , it is understood that the end plate  18  may include more or less of the ears  24  than shown. The axle housing  12  may be configured to releasably receive the ears  24  of the end plate  18  to militate against a rotational movement of the brake assembly  14  within the axle housing  12 . As best seen in  FIG.  3   , the end plate  18  may also include a central opening  26 . In an embodiment, the central opening  26  may provide a journaling function for an axle shaft (not depicted) that connects the prime mover to a drive gear assembly  28  of the wheel assembly  29 . As shown, the drive gear assembly  28  may include an output shaft  35  drivingly connected to an input shaft (e.g. the axle shaft) via a plurality of gears  27  disposed within a wheel housing  39  of the wheel assembly  29 . The output shaft  35  may be rotatably supported within the wheel housing  39  by at least one bearing  37  disposed between the wheel housing  39  and a wheel hub  41 . The wheel hub  41  may be configured to couple the output shaft  35  to the wheel of the vehicle. At least one seal  43  may be disposed between the wheel hub  41  and the wheel housing  39 . It should be appreciated that other types of wheel assemblies may be employ for the wheel assembly  29  as desired. 
     As illustrated, the annular housing  16  of the brake assembly  14  may include a first conduit  36 , a second conduit  38 , and annular grooves  40   a ,  40   b ,  40   c  formed in an outer circumferential surface thereof. The grooves  40   a ,  40   b ,  40   c  may be formed in the outer circumferential surface on opposing sides of each of the conduits  36 ,  38 . Seals  42   a ,  42   b ,  42   c  may be disposed in a respective one of the grooves  40   a ,  40   b ,  40   c  to form a substantially fluid tight seal between the axle housing  12  and the annular housing  16  of the brake assembly  14 . In certain embodiments, an interior cavity of the annular housing  12  may be divided by an annular web portion  29  into an annular first chamber  30  and an annular second chamber  31 . The first conduit  36  extends from the outer circumferential surface of the annular housing  16  of the brake assembly  14  to the first chamber  30 . The second conduit  38  extends from the outer circumferential surface of the annular housing  16  of the brake assembly  14  to the second chamber  31 . As best seen in  FIG.  1   , the first chamber  30  may be in fluid communication with the first port  15  via the first conduit  36  and the second chamber  31  may be in fluid communication with the second port  17  via the second conduit  38 . 
     The annular housing  16  of the brake assembly  14  may provide a housing for a brake mechanism  33  comprising a plurality of brake discs  32  and at least one separator plate  34 . In certain embodiments, the brake mechanism  33  may be an interchangeable brake mechanism  33  at least partially received in the annular housing  16 . In certain embodiments, the annular housing  16  may be a universal annular housing  16  having a profile configured to receive different configurations of the interchangeable brake mechanism  33 . The profile of the annular housing  16  of the brake assembly  14  may be configured to house various arrangements, configurations, sizes, shapes, and numbers of the brake discs  32  and the separator plates  34 . Accordingly, the annular housing  16  of the brake assembly  14  allows the interchangeable brake mechanism  33  having various brake discs  32  and/or separator plates  34  to be employed to meet different requirements of the end user while maintaining the profile of the annular housing  16 . It is understood that at least one of the brake discs  32  and the at least one separator plate  34  may be hardened so as to create an integral wear surface or have a coating deposited thereon to form the wear surface. 
     As more clearly shown in  FIG.  1   , the brake discs  32  and the at least on separator plate  34  are arranged within the first chamber  30  of the annular housing  12  in an alternating series. In the embodiment of  FIG.  1   , the brake assembly  14  includes four of the brake discs  32  in an alternating arrangement with five of the separator plates  34 . In other embodiments shown in  FIG.  5   , the brake assembly  14  includes three of the brake discs  32  in an alternating arrangement with four of the separator plates  34 . In yet other embodiments shown in  FIG.  6   , the brake assembly  14  includes two of the brake discs  32  in an alternating arrangement with three of the separator plates  34 . It is understood that the brake assembly  14  may include more or less of the brake discs  32  and/or the separator plates  34  than shown if desired. 
     As illustrated, the at least one separator plate  34  may be keyed to the annular housing  16  of the brake assembly. In certain embodiments, the at least one separator plate  34  includes a plurality of protuberances (not depicted) (e.g. splines, teeth, etc.) formed on an outer circumferential surface thereof. The protuberances of the at least one separator plate  34  may be configured to be in meshed engagement with a plurality of protuberances (not depicted) (e.g. splines, teeth, etc.) formed on an inner circumferential surface of the annular housing  16  to militate against a rotational movement between the at least one separator plate  34  and the annular housing  16  while permitting an axial movement thereof. 
     Each of the brake discs  32  and the at least one separator plate  34  may include a respective one of central openings  50 ,  52 . The central openings  50 ,  52  may provide a journaling function for the axle shaft. In certain embodiments, each of the brake discs  32  includes a plurality of protuberances  54  (e.g. splines, teeth, etc.) formed on an inner circumferential surface of the central openings  50 . The protuberances  54  of the brake discs  32  may be configured to be in meshed engagement with a plurality of protuberances (not depicted) (e.g. splines, teeth, etc.) formed on an outer circumferential surface of the axle shaft to militate against a rotational movement between the brake discs  32  and the axle shaft while permitting an axial movement thereof. Additionally, the brake discs  32  and/or the at least one separator plate  34  may include an annular array of apertures  56  formed therein to permit a flow of the fluid or a lubricant therethrough. 
     A first piston  60  may be disposed in the first chamber  30  adjacent the brake discs  32  and separator plates  34  opposite the end plate  18 . In certain embodiments, the first piston  60  may be an annular member  62  having a center bore  64  configured to receive the axle shaft therethrough. As illustrated, the annular member  62  of the first piston  60  may include annular grooves  66   a ,  66   b  formed in an outer circumferential surface thereof. The grooves  66   a ,  66   b  may be formed in the outer circumferential surface on opposing sides of the first conduit  36 . Seals  68   a ,  68   b  may be disposed in a respective one of the grooves  66   a ,  66   b  to form a substantially fluid tight seal between the annular housing  16  and the first piston  60 . Accordingly, a pressure in an activation cavity  69  formed between the first piston  60  and the annular housing  16  may be maintained and/or increased for activation of the first piston  60 . An injection of the pressured fluid into the activation cavity  69  causes the first piston  60  to move in a first axial direction from a disengaged first position towards the brake mechanism  33  to an engaged second position. 
     A biasing mechanism  70  may be disposed in the first piston  60  and secured to the annular housing  16  of the brake assembly  14 . In certain embodiments, the biasing mechanism  70  may include a pin member  72  fixedly attached to the web portion  29  of the annular housing  16  and a biasing element  74  (e.g. a helical spring) interposed between the pin member  72  and a portion of the first piston  60 . The biasing mechanism  70  may provide uniform biasing of the first piston  60  causing the first piston  60  to move in a second axial direction from the engaged second position towards the web portion  29  of the annular housing  16  to the disengaged first position. 
     When the first piston  60  is deactivated by ceasing the flow of the pressurized fluid to the activation cavity  69 , the first piston  60  is in the first position and the brake mechanism  33  is thereby disengaged having the brake discs  32  and the at least one separator plate  34  in an expanded state. In the expanded state, the brake discs  34  in meshed engagement with the axle shaft are permitted to rotate within the brake assembly  14  and the axle assembly to be driven. On the contrary, when the first piston  60  is activated by supplying the flow of the pressurized fluid to the activation cavity  69 , the first piston  60  is caused to be in the second position and the brake mechanism  33  is thereby engaged having the brake discs  32  and the at least one separator plate  34  in a compressed state. In the compressed state, frictional forces between the brake discs  34  and the at least one separator plate  34  causes a rotation of the brake discs  32  and the axle shaft in meshed engagement therewith to cease and the axle assembly to be stopped. 
     In certain embodiments, the first piston  60  may further include a valve  76  disposed through a bore  78  into the annular housing  16  of the brake assembly  14 . In certain embodiments, the valve  76  may include a housing  80  disposed in the bore  78  and a pin member  81  disposed through the housing  80  into the web portion  29  of the annular housing  16  of the brake assembly  14 . The valve  76  may provide a relief passageway for the fluid and/or lubricant located between the first piston  60  and the web portion  29  of the annular housing  16  when the first piston  60  moves in the second axial direction from the engaged second position back to the disengaged first position. 
     A second piston  90  may be disposed in the second chamber  31  adjacent the web portion  29  of the annular housing  16  of the brake assembly  14 . In certain embodiments, the second piston  90  may be an annular member  92  having a center bore  94  configured to receive the axle shaft therethrough. As illustrated, the annular member  92  of the second piston  90  may include annular grooves  96   a ,  96   b  formed in an outer circumferential surface thereof. The grooves  96   a ,  96   b  may be formed in the outer circumferential surface on opposing sides of the second conduit  38 . Seals  98   a ,  98   b  may be disposed in a respective one of the grooves  96   a ,  96   b  to form a substantially fluid tight seal between the annular housing  16  and the second piston  90 . Accordingly, a pressure in an activation cavity  99  formed between the second piston  90  and the annular housing  16  may be maintained and/or increased for activation of the second piston  90 . An injection of the pressured fluid into the activation cavity  99  causes the second piston  90  to move in the second axial direction from a first position adjacent the web portion  29  towards an open end  100  of the annular housing  16  to a second position. 
     A biasing mechanism  102  may be disposed in the second chamber  31 . In certain embodiments as best seen in  FIG.  2   , the biasing mechanism  102  may include at least one biasing element  104  (e.g. a disc spring, a wave spring, etc.) interposed between a portion of the second piston  90  and a positioning element  106 . In certain embodiments, the at least one biasing element  104  is pre-compressed during an installation into the annular housing  16  of the brake assembly  14 . When the brake assembly  14  includes the at least one pre-compressed biasing element  104 , the installation of the brake assembly  14  into the axle assembly  10  during production or the repair of the brake assembly  14  is simplified, particularly since specialized equipment to assemble the brake assembly  14  into the axle housing  12  of the axle assembly  10  is not necessary. The biasing mechanism  102  may provide uniform biasing of the second piston  90  causing the second piston  90  to move in the first axial direction from the second position adjacent the open end  100  of the annular housing  16  to the first position. As illustrated, the positioning element  106  may be generally ring-shaped having a central opening  108  formed therein. In an embodiment, the central opening  108  may provide a journaling function for the axle shaft. The positioning element  106  may be configured to maintain a position of an end or one side of the at least one biasing element  104  during operation of the second piston  90 . In certain embodiments, a portion of the positioning element  106  may surround an outer circumferential surface of the at least one biasing element  104 . A retainer  108  (e.g. a spring clip, circlip, snap ring, etc.) may be employed to maintain a position of the positioning element  106 . In certain embodiment, the retainer  108  may be at least partially received in a groove  110  formed in the inner circumferential surface of the annular housing  16  and at least partially received in an annular recess  112  formed in a face of the positioning element  106  opposite the at least one biasing element  104 . A ring-shaped collar  120  may be interposed between first piston  60  and the second piston  90 . 
     When the second piston  90  is deactivated by ceasing the flow of the pressurized fluid to the activation cavity  99 , the second piston  90  is urged by the biasing mechanism  102  into the first position or an expanded state, which causes the first piston  60  to be in the second position, and the brake mechanism  33  is thereby engaged having the brake discs  32  and the at least one separator plate  34  in a compressed state. In the compressed state, frictional forces between the brake discs  34  and the at least one separator plate  34  causes a rotation of the brake discs  32  and the axle shaft in meshed engagement therewith to cease and the axle assembly to be stopped. On the contrary when the second piston  90  is activated by supplying the flow of the pressurized fluid to the activation cavity  99 , the second piston  60  is caused to be in the second position and the biasing mechanism  102  is moved into a second position or a compressed state. When the second piston  90  is in the second position, depending on activation of the first piston  60 , the first piston  60  may be in either the first position with the brake mechanism  33  disengaged or the second position with the brake mechanism  33  engaged. 
       FIG.  7    shows another embodiment of a brake assembly  14 ′ of an axle assembly  10 ′ similar to that shown in  FIGS.  1 - 6    without the second piston  90 . Reference numerals for similar structure in respect of the description of  FIGS.  1 - 6    are repeated in  FIG.  7    with a prime (′) symbol. 
     The brake assembly  14 ′ may be configured as a cartridge style brake assembly that may be pre-assembled prior to installation into the axle housing  12 ′. The cartridge style brake assembly  14 ′ permits installation to be simplified and allows a manufacturer thereof to control an assembly process. Additionally, the brake assembly  14 ′ may be an interchangeable brake assembly  14 ′ at least partially received in the axle housing  12 ′. In certain embodiments, the axle housing  12 ′ may be a universal axle housing  12 ′ having a profile configured to receive different configurations of the interchangeable brake assembly  14 ′. 
     The brake assembly  14 ′ may include an annular housing  16 ′ and an end plate  18 ′ configured to be coupled to the axle housing  12 ′. Various methods may be employed to couple the end plate  18 ′ to the annular housing  16 ′ such as mechanical fasteners (not depicted), for example. In certain embodiments, the annular housing  16 ′ of the brake assembly  14 ′ may be received in a cavity  21 ′ formed in the axle housing  12 ′. The end plate  18 ′ may be secured to the axle housing  12 ′ by a plurality of mechanical fasteners (not depicted) to militate against an axial movement of the brake assembly  14 ′ within the axle housing  12 ′. It should be appreciated that the end plate  18 ′ may be coupled to the axle housing  12 ′ by any method as desired. As illustrated, the mechanical fasteners may be received through bores (not depicted) formed in an annular array of spaced apart ears  24 ′ radially extending from the end plate  18 ′. It is understood that the end plate  18 ′ may include any number of the ears  24 ′ as desired. The axle housing  12 ′ may be configured to releasably receive the ears  24 ′ of the end plate  18 ′ to militate against a rotational movement of the brake assembly  14 ′ within the axle housing  12 ′. The end plate  18 ′ may also include a central opening  26 ′. In an embodiment, the central opening  26 ′ may provide a journaling function for an axle shaft (not depicted) that connects the prime mover to a drive gear assembly (not depicted) of a wheel assembly (not depicted). As shown, the drive gear assembly may include an output shaft (not depicted) drivingly connected to an input shaft (e.g. the axle shaft) via a plurality of gears (not depicted) disposed within a wheel housing (not depicted) of the wheel assembly. The output shaft may be rotatably supported within the wheel housing by at least one bearing (not depicted) disposed between the wheel housing and a wheel hub (not depicted). The wheel hub may be configured to couple the output shaft to the wheel of the vehicle. At least one seal (not depicted) may be disposed between the wheel hub and the wheel housing. It should be appreciated that other types of wheel assemblies may be employ for the wheel assembly as desired. 
     As illustrated, the annular housing  16 ′ of the brake assembly  14 ′ may include a first conduit  36 ′ and annular grooves  40   b ′,  40   c ′ formed in an outer circumferential surface thereof. The grooves  40   b ′,  40   c ′ may be formed in the outer circumferential surface on opposing sides of the first conduit  36 ′. Seals  42   b ′,  42   c ′ may be disposed in a respective one of the grooves  40   b ′,  40   c ′ to form a substantially fluid tight seal between the axle housing  12 ′ and the annular housing  16 ′ of the brake assembly  14 ′. In certain embodiments, an interior cavity of the annular housing  12 ′ may be defined by an annular web portion  29 ′ forming an annular first chamber  30 ′. The first conduit  36 ′ extends from the outer circumferential surface of the annular housing  16 ′ of the brake assembly  14 ′ to the first chamber  30 ′. The first chamber  30 ′ may be in fluid communication with a first port  15 ′ via the first conduit  36 ′. In certain embodiments, the first port  15 ′ is an input port permitting a flow of the pressurized fluid from the fluid source into the axle housing  12 ′. In other embodiments, the universal axle housing  12 ′ may include a second port  17 ′ to accommodate other configurations of the brake assembly  14 ′. A third port  19 ′ may be formed in the axle housing  12 ′ as a drain or output port permitting a flow of a depressurized fluid from the axle housing  12 ′ back to the fluid source. Each of the ports  15 ′,  19 ′ may further include a respective valve  2 ′,  6 ′ to control the flow of the pressurized fluid to the brake assembly  14 ′ and/or the flow of the depressurized fluid from the brake assembly  14 ′. In embodiments where the axle housing  12 ′ includes the second port  17 ′, the second port  17 ′ may include a plug  90  disposed therein to militate against a flow of the fluid from the cavity  21 ′ of the axle housing  12 ′. 
     The annular housing  16 ′ of the brake assembly  14 ′ may provide a housing for a brake mechanism  33 ′ comprising a plurality of brake discs  32 ′ and at least one separator plate  34 ′. In certain embodiments, the brake mechanism  33 ′ may be an interchangeable brake mechanism  33 ′ at least partially received in the annular housing  16 ′. In certain embodiments, the annular housing  16 ′ may be a universal annular housing  16 ′ having a profile configured to receive different configurations of the interchangeable brake mechanism  33 ′. The profile of the annular housing  16 ′ of the brake assembly  14 ′ may be configured to house various arrangements, configurations, sizes, shapes, and numbers of the brake discs  32 ′ and the separator plates  34 ′. Accordingly, the annular housing  16 ′ of the brake assembly  14 ′ allows the interchangeable brake mechanism  33 ′ having various brake discs  32 ′ and/or separator plates  34 ′ to be employed to meet different requirements of the end user while maintaining the profile of the annular housing  16 ′. It is understood that at least one of the brake discs  32 ′ and the at least one separator plate  34 ′ may be hardened so as to create an integral wear surface or have a coating deposited thereon to form the wear surface. 
     The brake discs  32 ′ and the at least on separator plate  34 ′ are arranged within the first chamber  30 ′ of the annular housing  12 ′ in an alternating series. The brake assembly  14 ′ shown includes four of the brake discs  32 ′ in an alternating arrangement with five of the separator plates  34 ′. In other embodiments, the brake assembly  14 ′ may include three of the brake discs  32 ′ in an alternating arrangement with four of the separator plates  34 ′. In yet other embodiments, the brake assembly  14 ′ may include two of the brake discs  32 ′ in an alternating arrangement with three of the separator plates  34 ′. It is understood that the brake assembly  14 ′ may include more or less of the brake discs  32 ′ and/or the separator plates  34 ′ than shown if desired. 
     As illustrated, the at least one separator plate  34 ′ may be keyed to the annular housing  16 ′ of the brake assembly. In certain embodiments, the at least one separator plate  34 ′ includes a plurality of protuberances (not depicted) (e.g. splines, teeth, etc.) formed on an outer circumferential surface thereof. The protuberances of the at least one separator plate  34 ′ may be configured to be in meshed engagement with a plurality of protuberances (not depicted) (e.g. splines, teeth, etc.) formed on an inner circumferential surface of the annular housing  16 ′ to militate against a rotational movement between the at least one separator plate  34 ′ and the annular housing  16 ′ while permitting an axial movement thereof. 
     Each of the brake discs  32 ′ and the at least one separator plate  34 ′ may include a respective one of central openings  50 ′,  52 ′. The central openings  50 ′,  52 ′ may provide a journaling function for the axle shaft. In certain embodiments, each of the brake discs  32 ′ includes a plurality of protuberances  54 ′ (e.g. splines, teeth, etc.) formed on an inner circumferential surface of the central openings  50 ′. The protuberances  54 ′ of the brake discs  32 ′ may be configured to be in meshed engagement with a plurality of protuberances (not depicted) (e.g. splines, teeth, etc.) formed on an outer circumferential surface of the axle shaft to militate against a rotational movement between the brake discs  32 ′ and the axle shaft while permitting an axial movement thereof. Additionally, the brake discs  32 ′ and/or the at least one separator plate  34 ′ may include an annular array of apertures  56 ′ formed therein to permit a flow of the fluid or a lubricant therethrough. 
     A first piston  60 ′ may be disposed in the first chamber  30 ′ adjacent the brake discs  32 ′ and separator plates  34 ′ opposite the end plate  18 ′. In certain embodiments, the first piston  60 ′ may be an annular member  62 ′ having a center bore  64 ′ configured to receive the axle shaft therethrough. As illustrated, the annular member  62 ′ of the first piston  60 ′ may include annular grooves  66   a ′,  66   b ′ formed in an outer circumferential surface thereof. The grooves  66   a ′,  66   b ′ may be formed in the outer circumferential surface on opposing sides of the first conduit  36 ′. Seals  68   a ′,  68   b ′ may be disposed in a respective one of the grooves  66   a ′,  66   b ′ to form a substantially fluid tight seal between the annular housing  16 ′ and the first piston  60 ′. Accordingly, a pressure in an activation cavity  69 ′ formed between the first piston  60 ′ and the annular housing  16 ′ may be maintained and/or increased for activation of the first piston  60 ′. An injection of the pressured fluid into the activation cavity  69 ′ causes the first piston  60 ′ to move in a first axial direction from a disengaged first position towards the brake mechanism  33 ′ to an engaged second position. 
     A biasing mechanism  70 ′ may be disposed in the first piston  60 ′ and secured to the annular housing  16 ′ of the brake assembly  14 ′. In certain embodiments, the biasing mechanism  70 ′ may include a pin member  72 ′ fixedly attached to the web portion  29 ′ of the annular housing  16 ′ and a biasing element  74 ′ (e.g. a helical spring) interposed between the pin member  72 ′ and a portion of the first piston  60 ′. The biasing mechanism  70 ′ may provide uniform biasing of the first piston  60 ′ causing the first piston  60 ′ to move in a second axial direction from the engaged second position towards the web portion  29 ′ of the annular housing  16 ′ to the disengaged first position. 
     When the first piston  60 ′ is deactivated by ceasing the flow of the pressurized fluid to the activation cavity  69 ′, the first piston  60 ′ is in the first position and the brake mechanism  33 ′ is thereby disengaged having the brake discs  32 ′ and the at least one separator plate  34 ′ in an expanded state. In the expanded state, the brake discs  34 ′ in meshed engagement with the axle shaft are permitted to rotate within the brake assembly  14 ′ and the axle assembly to be driven. On the contrary, when the first piston  60 ′ is activated by supplying the flow of the pressurized fluid to the activation cavity  69 ′, the first piston  60 ′ is caused to be in the second position and the brake mechanism  33 ′ is thereby engaged having the brake discs  32 ′ and the at least one separator plate  34 ′ in a compressed state. In the compressed state, frictional forces between the brake discs  34 ′ and the at least one separator plate  34 ′ causes a rotation of the brake discs  32 ′ and the axle shaft in meshed engagement therewith to cease and the axle assembly to be stopped. 
     In certain embodiments, the first piston  60 ′ may further include a valve  76 ′ disposed through a bore  78 ′ into the annular housing  16 ′ of the brake assembly  14 ′. In certain embodiments, the valve  76 ′ may include a housing  80 ′ disposed in the bore  78 ′ and a pin member  81 ′ disposed through the housing  80 ′ into the web portion  29 ′ of the annular housing  16 ′ of the brake assembly  14 ′. The valve  76 ′ may provide a relief passageway for the fluid and/or lubricant located between the first piston  60 ′ and the web portion  29 ′ of the annular housing  16 ′ when the first piston  60 ′ moves in the second axial direction from the engaged second position back to the disengaged first position. 
     From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of the subject matter of the embodiments described herein and, without departing from the spirit and scope thereof, can make various changes and modifications to the embodiments to adapt them to various usages and conditions.