Patent Publication Number: US-11648983-B2

Title: Subframe assembly for a vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present disclosure is a continuation (CON) of co-pending U.S. patent application Ser. No. 16/829,365, filed on Mar. 25, 2020, and entitled “SUBFRAME ASSEMBLY FOR A VEHICLE,” the contents of which are incorporated in full by reference herein. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to the automotive field, and specifically the internal combustion engine (ICE) vehicle, hybrid-electric vehicle (HEV), and electric vehicle (EV) fields. More particularly, the present disclosure relates to a subframe assembly (e.g., a front subframe assembly) for a vehicle that includes a strong, rigid connection between a crossmember, a straight arm, and a side bracket in the area of a control arm connection for a wheel suspension. 
     BACKGROUND 
     In some conventional and novel ICE vehicle, HEV, and EV designs, the engine or motor is coupled to a front (or rear) subframe assembly that may be partially or wholly extruded for weight and costs savings, as well as structural strength and overall vehicle integrity in the event of a crash. Extruded aluminum, for example, provides many advantages over steel box and/or cast constructions. This subframe assembly typically consists of a frame-like structure that includes at least one extruded crossmember (and likely a pair of extruded crossmembers) disposed between a pair of elongate extruded arm members. The engine or motor is coupled to the subframe assembly via a plurality of mounts (i.e., engine mounts or motor mounts). 
     In different crash load cases, the subframe assembly can receive huge amounts of energy. Ideally, the subframe assembly itself absorbs a significant amount of that energy (and transfers what is left to the battery frame in the rear part of the subframe, for example), achieves a low vehicle pulse index (i.e., g-forces), and has little to no intrusion into the occupant compartment of the vehicle. 
     Some vehicle subframes are casted, and thus undesirably brittle in a crash, and are thus designed to detach from the vehicle in the event of a crash. In such cases, the brittle structure does not absorb much energy, and upon detachment, such as at the connection between a crossmember, a straight arm, and an attachment bracket for a control arm connection of the wheel assembly, no further energy is absorbed by the subframe assembly. Some subframe assemblies including a connection between a crossmember, a straight arm, and an attachment bracket are rather configured to collapse in a crash. When a subframe assembly collapses, the subframe assembly does not absorb very much energy. Similarly, some subframe assemblies have the attachment bracket positioned between the crossmember and the straight arm, which shortens the straight arm and results in extra welds that serve as weak points during a crash and can affect the ductility of the straight arm. The shorter straight arms absorb less energy and the subframe assembly collapses at the welds, resulting in very little energy being absorbed by the subframe. While the subframe assembly can be strengthened in these scenarios by connecting the subframe assembly to the vehicle body, such as by screws, these connections can result in increased noise, vibration, and ride harshness for the vehicle occupants. 
     The above-described background relating to the various connections between members of a subframe assembly is merely intended to provide a contextual overview of some current issues and is not intended to be exhaustive. Other contextual information may become apparent to those of ordinary skill in the art upon review of the following description of exemplary embodiments. 
     SUMMARY 
     The present disclosure generally provides a subframe assembly with a strong, rigid connection between a crossmember, a straight arm, and a side bracket in an area of a control arm connection for a wheel suspension. In particular, the side bracket is metallurgically bonded to a side of the straight arm (at or close to an end of the straight arm), and both the side bracket and the straight arm are received into and metallurgically bonded to an end bracket of the crossmember, with the end bracket being positioned at an end of the crossmember. The use of this strong, rigid connection between the various components provides for the desired rigidity, ductility, and strength of the connection and its components, and in particular, the length, rigidity, and ultimate deformability of the straight arm, for a desired crashworthiness of the subframe assembly. 
     In one exemplary embodiment, the present disclosure provides a subframe assembly for a vehicle that includes a crossmember, a straight arm, and a side bracket. The crossmember includes an end bracket disposed at an end thereof. The straight arm is received into and metallurgically bonded to the end bracket of the crossmember. The side bracket includes a base and a rear bracket arm. The base is metallurgically bonded to a side of the straight arm adjacent to the end of the crossmember. The rear bracket arm extends from an end of the base and defines a hole adapted to receive a screw or pin for connecting a control arm of a wheel suspension to the subframe assembly. The rear bracket arm is at least partially received into and metallurgically bonded to the end bracket of the crossmember. 
     In one exemplary embodiment of the subframe assembly, a portion of the rear bracket arm protrudes from the end bracket of the crossmember and metallurgical bonds are formed at interfaces between the end bracket of the crossmember and protruding surfaces of the rear bracket arm. In another exemplary embodiment of the subframe assembly, the rear bracket arm includes an arm portion extending from and disposed orthogonal to the base and a body portion extending from the arm portion, the body portion extending beyond an end of the base, being offset from the base, and defining the hole. Optionally, the body portion defines a wedge shape with a truncated thin edge distal to the arm portion, the truncated thin edge being disposed proximal to a back portion of the crossmember. Optionally, the truncated thin edge defines an end surface of the rear bracket arm, and the end surface and top and bottom base surfaces of the wedge shape protrude from the end bracket of the crossmember. Optionally, metallurgical bonds are formed on protruded portions of each of the end surface, the top base surface, and the bottom base surface at edges of the end bracket of the crossmember that join the side bracket to the crossmember. Optionally, metallurgical bonds are also formed on side surfaces of the arm portion and the base at the edges of the end bracket of the crossmember that also join the side bracket to the crossmember. In a further exemplary embodiment of the subframe assembly, the straight arm defines a depression at an upper surface thereof adjacent to the side surface, and the depression is offset from the side bracket such that the depression does not overlap with the side bracket along a length of the straight arm. In a still further exemplary embodiment of the subframe assembly, the base is offset from the end of the straight arm. 
     In another exemplary embodiment, the present disclosure provides a side bracket adapted to connect a control arm of a wheel suspension to a subframe assembly for a vehicle. The side bracket includes a base, a middle bracket arm, and a rear bracket arm. The base is adapted to be metallurgically bonded to a side of a straight arm of the subframe assembly adjacent to an end of the straight arm. The middle bracket arm extends from and is disposed orthogonal to the base between ends of the base. The middle bracket arm defines a clearance hole adapted to receive a screw or pin adapted to connect the control arm to the subframe assembly. The rear bracket arm includes an arm portion and a body portion. The arm portion extends from and is disposed orthogonal to the base. The body portion extends from the arm portion. The body portion extends beyond one of the ends of the base, is offset from the base, and defines a hole adapted to receive the screw or pin. The body portion is adapted to be at least partially received into and metallurgically bonded to an end bracket of a crossmember of the subframe assembly. The end bracket is disposed at an end of the crossmember. 
     In one exemplary embodiment of the side bracket, the body portion defines a wedge shape with a truncated thin edge distal to the arm portion, the truncated thin edge defining an end surface adapted to be disposed proximal to a back portion of the crossmember. Optionally, the end surface and top and bottom base surfaces of the wedge shape are adapted to protrude from the end bracket of the crossmember. Optionally, the body portion defines an inner surface facing the middle bracket that defines an opening to the hole, and the body portion tapers from the inner surface to the end surface. Optionally, the body portion defines an angled surface distal to the arm portion that extends between the end surface and the inner surface, and an offset surface disposed proximal to the arm portion that extends parallel to and offset from a bottom surface of the base, the angled surface and the offset surface forming an acute angle. 
     In a further exemplary embodiment, the present disclosure provides a method for manufacturing a subframe assembly for a vehicle. The method includes metallurgically bonding a base of a side bracket to a side surface of a straight arm, wherein the side bracket includes the base and a rear bracket arm extending from an end of the base and defining a hole adapted to receive a screw or pin for connecting a control arm of a wheel suspension to the subframe assembly. The method also includes inserting an end of the straight arm and at least a portion of the rear bracket arm into an end bracket of a crossmember, wherein the end bracket is disposed at an end of the crossmember. The method further includes metallurgically bonding each of the end of the straight arm and the rear bracket arm to the end bracket of the crossmember. 
     In one exemplary embodiment of the method, the method further includes inserting an end of the base into the end bracket and metallurgically bonding the end of the base to the end bracket of the crossmember. In another exemplary embodiment of the method, a portion of the rear bracket arm protrudes from the end bracket of the crossmember, and metallurgically bonding the rear bracket arm to the end bracket of the crossmember includes forming metallurgical bonds at interfaces between the end bracket of the crossmember and protruding surfaces of the rear bracket arm. In a further exemplary embodiment of the method, the rear bracket arm includes an arm portion extending from and disposed orthogonal to the base and a body portion extending from the arm portion, the body portion extending beyond an end of the base, being offset from the base, and defining the hole, and inserting the end of the straight arm and the at least the portion of the rear bracket arm into the end bracket of the crossmember includes positioning the end of the straight arm and an end of the body portion proximal to a back portion of the crossmember. In a still further exemplary embodiment of the method, metallurgically bonding the base of the side bracket to the side surface of the straight arm includes locating the side bracket such that the base is offset from the end of the straight arm. In still a further exemplary embodiment of the method, the straight arm defines a depression at an upper surface thereof adjacent to the side surface, and metallurgically bonding the base of the side bracket to the side surface includes locating the side bracket such that the side bracket does not overlap with the depression along a length of the straight arm. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure is illustrated and described herein with reference to the various drawings, in which like reference numbers are used to denote like system components/method steps, as appropriate, and in which: 
         FIG.  1    is a perspective view of one exemplary embodiment of the (front) subframe assembly of the present disclosure; 
         FIG.  2    is a partial perspective view of the subframe assembly of  FIG.  1    at a connection between the (rear) crossmember, a straight arm, and a side bracket with a lower control arm of the wheel suspension connected thereto; 
         FIG.  3    is an exploded partial perspective view of the subframe assembly of  FIG.  1    at the connection shown in  FIG.  2    with the lower control arm of the wheel suspension; 
         FIG.  4    is a side perspective view of the side bracket of  FIGS.  1 - 3   ; 
         FIG.  5    is a partial perspective view of the subframe assembly of  FIG.  1    at the connection shown in  FIG.  2   , illustrating locations of metallurgical bonds between members of the connection; 
         FIG.  6    is an alternative view of the partial perspective view of  FIG.  5    illustrating locations of the metallurgical bonds between members of the connection; 
         FIG.  7    is a flowchart of a method for manufacturing a subframe assembly for a vehicle; and 
         FIG.  8    is a side perspective view of the subframe assembly of  FIG.  1    deformed from absorbing energy during a crash event. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Again, the present disclosure generally provides a subframe assembly with a strong, rigid connection between a crossmember, a straight arm, and a side bracket in an area of a control arm connection for a wheel suspension. In particular, the side bracket is metallurgically bonded to the straight arm (at or close to an end of the straight arm), and both the side bracket and the straight arm are received into and metallurgically bonded to an end bracket of the crossmember with the end bracket being positioned at an end of the crossmember. The crossmember, the straight arm, and the side bracket can each be extruded aluminum, for example, having high-ductility and high-strength material properties. 
     The use of this strong, rigid connection provides for the desired rigidity, ductility, and strength of the connection and its components for a desired crashworthiness of the subframe assembly. In a crash event, the subframe assembly can deform, such as by bending into a U-shape, without detaching from the vehicle, while avoiding stack-up with other parts of the vehicle. In particular, the straight arm can bend in a designed location without interference from the side bracket to facilitate the desired deformation of the subframe assembly. 
       FIG.  1    is a perspective view of one exemplary embodiment of the (front) subframe assembly  10  of the present disclosure. Referring to  FIG.  1   , in one exemplary embodiment, the subframe assembly  10  of the present disclosure includes a front crossmember  20 , a rear crossmember  30 , straight arms  50 , and side arm brackets  100 . Each of the front crossmember  20 , the rear crossmember  30 , the straight arms  50 , and the side arm brackets  100  can include an extruded metal structure, such as an aluminum structure, having high-ductility and high-strength material properties. In some embodiments, at least the straight arms  50  are rectangular extruded structures. The use of extruded metal structures can provide a desired ductility and strength in the event of a crash, while keeping weight of the subframe assembly  10  to a minimum. 
     By way of example, the front crossmember  20 , the rear crossmember  30 , and the straight arms  50  may form a generally rectangular frame structure, which may include other spanning members that provide the frame structure with structural integrity and stability. This structural integrity and stability can further be established at the connections  15 . At each connection  15 , and as will be discussed in greater detail below, the rear crossmember  30 , a straight arm  50 , and a side bracket  100  are all metallurgically bonded to one another to form a strong, rigid connection. 
       FIG.  2    is a partial perspective view of the subframe assembly  10  of  FIG.  1    at the connection  15  between the rear crossmember  30 , the straight arm  50 , and the side bracket  100  with a lower control arm  200  of the wheel suspension connected thereto.  FIG.  3    is an exploded partial perspective view of the subframe assembly  10  of  FIG.  1    at the connection  15  shown in  FIG.  2    with the lower control arm  200  of the wheel suspension.  FIG.  4    is a side perspective view of the side bracket  100  of  FIGS.  1 - 3   . Referring to  FIGS.  2  and  3   , the rear crossmember  30  includes an end bracket  34  disposed at an end thereof. The rear crossmember  30  includes a back portion  32  extending a length of the rear crossmember  30 , and an upper bracket arm  36  and a lower bracket arm  38 , each extending from the end of the back portion  32  on opposite sides of the back portion  32 . The back portion  32 , the upper bracket arm  36 , and the lower bracket arm  38  combine to form a U-shaped end bracket  34 . While only one U-shaped end bracket  34  is described, a second U-shaped end bracket  34  can be located at an opposite end of the rear crossmember  30 , as can be seen in  FIG.  1   . 
     The straight arm  50  can define a depression  52  at an upper surface thereof adjacent to the side surface of the straight arm  50 . The depression  52  can be a slot extending across and transverse to a length of the straight arm  50 . An end of the straight arm is received into and metallurgically bonded to the end bracket  34  of the rear crossmember  30 . 
     The side bracket  100  includes a base  110 , a middle bracket arm  120 , and a rear bracket arm  130 . The base  110  is metallurgically bonded to the side of the straight arm  50  adjacent to the end of the rear crossmember  30 , and in particular, to the side located on an outer side of the subframe assembly  10 . As can be seen in  FIG.  1   , the base  110  is metallurgically bonded to the side of the straight arm  50  in a position so that the depression  52  of the straight arm  50  is offset from the side bracket  100  such that the depression  52  does not overlap with the side bracket  100  along a length of the straight arm  50 . The base  110  can also be offset from an end of the straight arm  50 . 
     Referring to  FIG.  4   , the middle bracket arm  120  extends from and is disposed orthogonal to the base  110  between ends  114  of the base. The middle bracket arm  120  defines a clearance hole adapted to receive a control arm fastener  210 , such as a screw or pin. As can be seen in  FIGS.  2  and  3   , the control arm fastener  210  is adapted to connect the control arm  200  of the wheel suspension, at a control arm bushing  205 , to the subframe assembly  10 . 
     The rear bracket arm  130  extends from an end  114  of the base and defines a hole  136  adapted to receive the control arm fastener  210 . As can be seen in  FIGS.  2  and  3   , the rear bracket arm  130  is at least partially received into and metallurgically bonded to the end bracket  34  of the rear crossmember  40 . 
     The rear bracket arm  130  includes an arm portion  132  and a body portion  134 . The arm portion  132  can extend from and be disposed orthogonal to the base  110 . The body portion  134  can extend from the arm portion  132 . The body portion  134  can extend beyond one of the ends  114  of the base  110  and can be offset from the base  110 . Here, the body portion  134  defines the hole  136 . As can be seen in  FIGS.  2  and  3   , the body portion  134  is adapted to be at least partially received into and metallurgically bonded to the end bracket  34  of the rear crossmember  40 . 
     The body portion  134  defines a wedge shape with a truncated thin edge distal to the arm portion  132 . The truncated thin edge can define an end surface  138 . The end surface  138  can be disposed proximal to the back portion  32  of the rear crossmember  40 . As the base  110  can be offset from an end of the straight arm  50 , the base  110  can be positioned such that the end surface  138  aligns with the end of the straight arm  50 . 
     The wedge shape of the body portion  134  also defines base surfaces (top and bottom)  140 , an inner surface  142 , an offset surface  144 , and an angled surface  146 . As can be seen in  FIG.  2   , the end surface  138 , and the base surfaces  140  of the wedge shape can protrude from the end bracket  34  of the rear crossmember  40 . 
     The inner surface  142  faces the middle bracket  120  and defines an opening to the hole  136 . The body portion  134  can taper from the inner surface  142  to the end surface  138 . The angled surface  146  can be distal to the arm portion  132  and can extend between the end surface  138  and the inner surface  142 . The offset surface  144  can be disposed proximal to the arm portion  132  and can extend parallel to and offset from a bottom surface  112  of the base  110 . The angled surface  146  and the offset surface  144  can form an acute angle. 
     As disclosed above, the connection  15  is formed by metallurgically bonding the side bracket  110  to a side of the straight arm  50 , and metallurgically bonding both the side bracket  110  and the straight arm  50  to the rear crossmember  30 . Each of the metallurgical bonds can be a weld or other bond with the desired strengths and properties. 
       FIG.  5    is a partial perspective view of the subframe assembly  10  of  FIG.  1    at the connection  15  shown in  FIG.  2   , illustrating locations of metallurgical bonds  16 ,  17 ,  18  between members of the connection  15 .  FIG.  6    is an alternative view of the partial perspective view of  FIG.  5   , illustrating locations of the metallurgical bonds  16 ,  17 ,  18  between members of the connection  15 . Referring to  FIGS.  5  and  6   , metallurgical bonds  16  join the side bracket  110  to the straight arm  50 , metallurgical bonds  17  join the side bracket  110  to the rear crossmember  30 , and metallurgical bonds  18  join the straight arm  50  to the rear crossmember  40 . In  FIGS.  5  and  6   , some of the metallurgical bonds  16 ,  17 , and  18  are behind the structures shown, but are still illustrated for informational purposes. The metallurgical bonds  16 ,  17 , and  18  can be continuous bonds, separate bonds, and a combination thereof. 
     In particular, the metallurgical bonds  16  can be formed along the sides of the base  110  and along the end  114  of the base  110  opposite the rear bracket arm  120  adjacent to the bottom surface  112  of the base  110 . The metallurgical bonds  16  can join the sides of the base  110  and the end  114  to the side surface of the straight arm  50 . 
     A portion of the rear bracket arm  130  can protrude from the end bracket  34  of the rear crossmember  30  and the metallurgical bonds  17  can be formed at interfaces between the end bracket  34  of the rear crossmember  30  and protruding surfaces of the rear bracket arm  130 . In particular, the metallurgical bonds  17  can be formed on protruding portions of each of the end surface  138 , the top and bottom base surfaces  140  at edges of the end bracket  34  of the rear crossmember  30  to join the side bracket  100  to the rear crossmember  30 . The metallurgical bonds  17  can also be formed on side surfaces of the arm portion  132  and the base  110  at the edges of the end bracket  34  of the rear crossmember  34  that also join the side bracket  100  to the rear crossmember  30 . As such, the top and bottom base surfaces  140  can be joined to front and side edges of the upper and lower bracket arms  36  and  38  of the end bracket  34 , and the end surface  138  can be joined to a side edge of the back portion  32  at the end bracket  34 . 
     The metallurgical bonds  18  can be formed at interfaces between the end bracket  34  of the rear crossmember  30 , and top and bottom surfaces of the straight arm  50  where the top and bottom surfaces begin to protrude from the end bracket  34 . These metallurgical bonds  18  can extend orthogonal to the length direction of the straight arm  50  and can be continuous with one or more of the metallurgical bonds  17 . Metallurgical bonds  18  can also be formed at interfaces between the inside surface of the straight arm  50 , opposite the side surface to which the side bracket is metallurgically bonded to, and internal surfaces of the end bracket  34  (in particular, surfaces of the back portion  32 , upper bracket arm  36  and lower bracket arm  38 ). As such, the top and bottom surfaces of the straight arm  50  can be joined to front edges of the upper and lower bracket arms of the end bracket  34 , and the inside surface of the straight arm  50  can be joined to the internal surfaces of the back portion  32 , the upper bracket arm  36  and the lower bracket arm  38 . 
       FIG.  7    is a flowchart of a method  700  for manufacturing a subframe assembly for a vehicle. The method  700  includes metallurgically bonding a base  110  of a side bracket  100  to a side surface of a straight arm  50  at step  702 . The side bracket includes the base  110  and a rear bracket arm  130  extending from an end of the base  110  and defines a hole  136  adapted to receive a screw or pin for connecting a control arm  200  of a wheel suspension to the subframe assembly  10 . The method also includes inserting an end of the straight arm  50  and at least a portion of the rear bracket arm  130  into an end bracket  34  of a crossmember  30  at step  704 . The end bracket  34  is disposed at an end of the crossmember  30 . The method further includes metallurgically bonding each of the end of the straight arm  50  and the rear bracket arm  130  to the end bracket  34  of the crossmember  30  at step  706 . 
     The method can include inserting an end of the base  110  into the end bracket  34  and metallurgically bonding the end of the base  110  to the end bracket  34  of the crossmember  30 . In embodiments, a portion of the rear bracket arm  130  can protrude from the end bracket  34  of the crossmember  30 , and the step of metallurgically bonding the rear bracket arm  130  to the end bracket  34  of the crossmember  30  includes forming metallurgical bonds  17  at interfaces between the end bracket  34  of the crossmember  30  and protruding surfaces of the rear bracket arm  130 . 
     Further, the rear bracket arm  130  can include the arm portion  132  extending from and disposed orthogonal to the base  110  and a body portion  134  extending from the arm portion  132  with the body portion  134  extending beyond an end of the base  110 , being offset from the base  110 , and defining the hole  136 . The step of inserting the end of the straight arm  50  and the at least the portion of the rear bracket arm  130  into the end bracket  34  of the crossmember  30  includes positioning the end of the straight arm  50  and an end of the body portion  134  proximal to a back portion  32  of the crossmember  30 . 
     Yet further, the step of metallurgically bonding the base  110  of the side bracket  100  to the side surface of the straight arm  50  can include locating the side bracket  100  such that the base  110  is offset from the end of the straight arm  50 . Still further, the straight arm  50  can define a depression  52  at an upper surface thereof adjacent to the side surface, and the step of metallurgically bonding the base  110  of the side bracket  100  to the side surface includes locating the side bracket  100  such that the side bracket  100  does not overlap with the depression  52  along a length of the straight arm  50 . Thus, the metallurgical bonds of the side bracket  100  are only on a single end of the straight arm  50  relative to the depression  52  to prevent further stiffening of the subframe assembly  10  at the depression  52 . 
     As discussed above, the connection  15  as disclosed herein can form a strong and rigid connection between the rear crossmember  30 , the straight arm  50 , and the side bracket  100  in the area of the control arm connection of a wheel suspension, while maintaining a long length of the straight arm  50  that is unencumbered by rigid connections to other components of the subframe assembly  10 . This can preserve a desired ductility of the straight arm  50  over that length. This is at least partially facilitated by metallurgically bonding the side bracket  100  to a side of the straight arm  50  at an end thereof. This overall configuration along with the use of extruded metals for various components of the subframe assembly  10  can result in the subframe  10  having the ductility needed to properly deform and absorb energy during a crash event. 
     In different crash load cases, the subframe assembly  10  can receive huge amounts of energy.  FIG.  8    is a side perspective view of the subframe assembly  10  of FIG.  1  deformed from absorbing energy during a crash event. As can be seen in  FIG.  8   , during the crash event, the straight arm  50  can bend, such as at the location of the depression  52  and the subframe assembly  10  can generally deform into a U-shape, while the connections, such as the connection  15  stay intact due to the strength and rigidity of the connections. Other members of the subframe assembly  10  can also deform and absorb energy. 
     This deformation, while the connections are maintained, can result in the subframe assembly  10  absorbing a significant amount of energy during the crash event, which can prevent too much energy transfer from the subframe assembly  10  to the occupant compartment, can achieve a low vehicle pulse index and can prevent intrusion into the occupant compartment. Further, the deformation of the subframe assembly  10  into a U-shape can avoid stack-up with other parts of the vehicle. 
     Further, the connection  15  can simplify the connection to the lower control arm  200 . As can be seen in  FIGS.  2  and  3   , the control arm bush  205  can be secured to the subframe assembly  10  via the side bracket  100  by a single control arm fastener  210 , while other solutions require significantly more components and fasteners. 
     Further, the strong and rigid connection  15  between the rear crossmember  30 , the straight arm  50 , and the side bracket  100  as disclosed herein can strengthen the subframe assembly  10  so that the subframe assembly  10  is more durable under high misuse and endurance loads. Such durability is particularly important for heavy vehicles, such as EV vehicles. 
     Although the present disclosure is illustrated and described herein with reference to preferred embodiments and specific examples thereof, it will be readily apparent to those of ordinary skill in the art that other embodiments and examples may perform similar functions and/or achieve like results. All such equivalent embodiments and examples are within the spirit and scope of the present disclosure, are contemplated thereby, and are intended to be covered by the following non-limiting claims for all purposes.