Patent Publication Number: US-2013229005-A1

Title: Vehicle Cross-Member Assembly with Adhesive Reservoirs

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation and claims the benefit of U.S. patent application Ser. No. 13/221,142 titled “Vehicle Support Frames with Interlocking Features for Joining Members of Dissimilar Materials” filed Aug. 30, 2011, U.S. patent application Ser. No. 13/239,592 titled “Vehicle Support Frames with Interlocking Features for Joining Members of Dissimilar Materials” filed Sep. 22, 2011, and U.S. patent application Ser. No. 13/545,584 titled “Vehicle Support Frames with Interlocking Features for Joining Members of Dissimilar Materials” filed Jul. 10, 2012, which are hereby incorporated by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to vehicle support frames with rails having dissimilar materials and methods for manufacturing the same. 
     BACKGROUND 
     Conventional vehicle support frames can be composed of different materials including, for example, steel, aluminum and reinforced polymer composites. Vehicle manufacturers attempt to strike a balance between weight reduction and structural rigidity. It is desirable to design lightweight vehicle frames for full-sized light trucks. Aluminum structural members can be designed to achieve up to a 50% weight reduction while still meeting performance targets. Joining aluminum members to steel frame rails presents challenges as the two materials, when welded, have limited structural integrity. 
     One existing reference teaches the use of an overlapping configuration for the rails of dissimilar materials. A first and second structural member sandwiches one end of a third structural member and adhesive is applied therebetween. The second structural member is thereafter welded to the first structural member. U.S. Patent Publication No. 2009/0188206, titled “System and Method for Joining Dissimilar Materials” teaches an overlapping configuration with a surface weld on the second structural member. Still, it is desirable to have a vehicle cross-member assembly as opposed to a collinear assembly; it is also desirable to improve this design by providing a point of access for spot weld fixtures or other weld fixtures that require a clamped fitting. 
     Therefore, it is desirable to have improved interconnecting techniques for joining two structural members composed of dissimilar materials. 
     SUMMARY 
     The present disclosure addresses one or more of the above-mentioned issues. Other features and/or advantages will become apparent from the description which follows. 
     One exemplary embodiment of the present disclosure relates to a method of manufacturing a vehicle cross-member assembly, includes: adding adhesive to an adhesive reservoir in an interconnecting member composed of a first material; overlapping a first rail composed of a second material with the interconnecting member; and welding the interconnecting member to a second rail in a position perpendicular with respect to the second rail. The second rail is composed of a different material than the first rail. 
     Another exemplary embodiment of the present disclosure relates to a method of manufacturing a vehicle cross-member assembly, the method including: adding adhesive to an adhesive reservoir in a first rail composed of a first material; overlapping an interconnecting member composed of a second material with the first rail; and welding the interconnecting member to the second rail in a position perpendicular to the second rail. The second rail is composed of a different material than the first rail. 
     Another exemplary embodiment of the present disclosure relates to a vehicle cross-member assembly, having: a first rail composed of a first material; a second rail, perpendicularly positioned with respect to the first rail, composed of a second material; and an interconnecting member composed of the second material having adhesive in reservoirs formed thereon to join the interconnecting member and the first rail. The interconnecting member is welded to the second rail. 
     Yet another exemplary embodiment of the present disclosure relates to a vehicle cross-member assembly, having: a first rail composed of a first material having adhesive in reservoirs formed thereon; a second rail, perpendicularly positioned with respect to the first rail, composed of a second material; and an interconnecting member composed of the second material. The interconnecting member is welded to the second rail. 
     One advantage of the present disclosure is that it provides improved interconnecting techniques for joining two structural members composed of dissimilar materials. 
     Another advantage of the present disclosure is that it teaches the manufacture and use of light-weight vehicle structural frames that can be utilized with vehicles of different sizes, including full-sized truck frames. The weight reduction for the disclosed frame assemblies compared to contemporary structural frames can be as great as 50%. Fuel efficiency and performance can be enhanced by the use of the disclosed frame assemblies. 
     Another advantage of the present disclosure is that it teaches joining techniques for structural members having dissimilar material composition and a closed-section configuration. Structural members can be positioned at any angle with respect to each other. 
     Joining vehicle frame assembly rails composed of dissimilar materials will be explained in greater detail below by way of example with reference to the figures, in which the same reference numbers are used in the figures for identical or essentially identical elements. The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. In the figures: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top perspective view of a vehicle support frame assembly. 
         FIG. 2  is a partial perspective view of the vehicle support frame assembly of  FIG. 1  at circle  2 . 
         FIG. 3  is a perspective view of the interconnecting member of  FIG. 2 . 
         FIG. 4  is a perspective view illustrating application of adhesive in reservoirs formed in the interconnecting member of  FIG. 3 . 
         FIG. 5  is a perspective view illustrating the assembly of the interconnecting member and cross rail of  FIG. 2 . 
         FIG. 6  is a perspective view of a die for forming recesses in a cross rail. 
         FIG. 7  is a partial perspective view of another exemplary vehicle support frame assembly with adhesive outside of the interconnecting member. 
         FIG. 8  is a partial perspective view the vehicle support frame assembly of  FIG. 7  from the inside of the cross rail. 
         FIG. 9  is a perspective view illustrating application of adhesive outside of an interconnecting in another exemplary vehicle support frame assembly. 
         FIG. 10  is a partial perspective view of the vehicle support frame assembly of  FIG. 9  illustrating application of adhesive inside of the cross rail at the corners. 
         FIG. 11  is a partial perspective view of the interconnecting member of  FIG. 9 . 
         FIG. 12  is a perspective view of another exemplary embodiment of an interconnecting member and rail with adhesive outside of the interconnecting member. 
         FIG. 13  is a partial perspective view the vehicle support frame assembly of  FIG. 12  from the inside of the cross rail. 
         FIG. 14  is a cross-sectional view the vehicle support frame assembly of  FIG. 12  at line  14 - 14 . 
         FIG. 15  is an assembly view of another exemplary vehicle support frame assembly. 
         FIG. 16  is a perspective view of the interconnecting member for use with the vehicle support frame assembly of  FIG. 15 . 
         FIG. 17  is as perspective view of another exemplary interconnecting member for use with a vehicle support frame assembly. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings, wherein like characters represent examples of the same or corresponding parts throughout the several views, there are shown vehicle support frames having joined structural members composed of different materials. Particularly, lighter weight aluminum structural members are joined to steel side rails in most embodiments. The aluminum and steel members are joined through an interconnecting member juxtaposed between them. The disclosed interconnecting members mitigate several challenges incumbent with joining dissimilar materials by teaching an interconnecting member having multiple portions. Each portion can be composed of a different material. Once attached to each other the portions form as a link or bridge between rails attached to a portion of the interconnecting member. In some embodiments, the rails are attached to the interconnecting member via MIG welding. 
     The teachings herein are applicable to any type of vehicle frame including frames for pickup trucks, vans, minivans, sports utility vehicles, sedans, coupes, commercial vehicles, and all utility vehicles. 
     Referring now to  FIG. 1 , there is shown therein a vehicle cross-member assembly (or support frame)  10 . The illustrated cross-member assembly  10  is configured for use in a pickup truck. Cross-member assembly  10  (as shown) is taken from the rear section of the truck frame, which supports the truck bed (not shown). Assembly  10  is a support frame. Side rail assemblies  20  and  30  extend longitudinally with respect to the assembly  10  and the vehicle. In the shown embodiment, side rail assemblies  20 ,  30  can be composed of different materials. Rails  20 ,  30  can be formed via any standard forming process, e.g., stampings, hydro-forming, or roll forming. The rearward ends of the rails  20 ,  30  are interconnected through a rearward steel cross-member  40 . Attached to cross-member  40  is a tow hitch  50 . Each end of the rails is fitted with a side bracket  60  for interconnecting cross-member  40  with the rails and for connecting the rails  20 ,  30  to other vehicle structure (e.g., the truck bed, rear fascia or bumper, etc.). At the frontward end of the cross-member assembly  10 , shown in  FIG. 1 , there is another steel cross-member  70  intersecting each side rail  20 ,  30 . As shown, rails  20 ,  30  are welded to cross-member  70 . 
     Rails  90 ,  100  (as shown in  FIG. 1 ) are positioned perpendicularly with respect to rails  20 ,  30 . Rails  90 ,  100  are a part of a spare tire support frame  75 . Rails  90 ,  100  are fitted with an interconnecting member  80 , as discussed hereinbelow. Rails  90 ,  100  are mechanically interlocked with interconnecting member  80 . As discussed below, in this embodiment, adhesive is used to attach the interconnecting member to rails. 
     Now with reference to  FIG. 2  there is shown a partial perspective view of the cross-member assembly  10  of  FIG. 1  at circle  2 . The assembly  10  has rails  20  and  100  composed of different materials. The material used for side rail  20  is not weld compatible with the material used for the rail  100 . In this embodiment, the side rail  20  is composed of steel and the cross rail  100  is made of aluminum. 
     Shown in  FIG. 2  is an intersection of the side rail  20 , interconnecting member  80  and rail  100 . Interconnecting member (or “ICM”)  80  passes through side rail  20  at a 90 degree angle or perpendicularly. ICM  80  is welded to side rail. Interconnecting member  80  is a steel tube in the illustrated embodiment of  FIG. 2 . 
     As shown in  FIG. 3 , the interconnecting member  80  has a series of oblong recesses or reservoirs  110  formed via crimping on an outer surface of the interconnecting member. Reservoirs are configured to hold adhesive  120  therein, as shown in  FIG. 4 . Different types of adhesives can be used including e.g., resins or two-way epoxies. Rail  100  also includes a series of crimps  130  (as shown in  FIG. 2 ) formed on the outer surface of rail  100 . Crimps  130  are located at the same longitudinal position as reservoirs  110  when the interconnecting member  80  is assembled with the rail  100  to form an interlock between the two members. In the illustrated embodiment, rail  100  includes eight crimps  130 . 
     The support frame assembly of  FIGS. 2-3  is manufactured using a method of manufacture as described hereinbelow. The method includes the steps of: (1) adding adhesive to an adhesive reservoir in an interconnecting member, as shown and discussed with respect to  FIG. 4 ; (2) overlapping the cross-member and the interconnecting member, e.g., as shown in  FIG. 5 ; (3) performing a second crimping; and (4) welding the interconnecting member to a side rail, in a position perpendicular with respect to the second rail, as shown in  FIG. 2 . 
     With respect to the first step, adding adhesive to an adhesive reservoir in the interconnecting member, this step is shown in  FIG. 4 . In  FIG. 4  an operator, O, is shown holding the interconnecting member  80  in one hand and an adhesive applicator  140  in the other hand. Adhesive  120  is inserted in the reservoirs  110 . In this embodiment, adhesive  120  is applied to fill the reservoirs  110 . Less or more adhesive can be used. 
     Once the adhesive is applied, the operator moves to the next step, as shown in  FIG. 5 . The rail  100  and interconnecting member  80  are positioned in an overlapping configuration, as shown in  FIG. 5 . In this embodiment, ICM  80  is inserted in the rail  100  with a spatial gap of approximately 0.5 mm between the inner surface of rail and the outer surface of ICM on each side. In other embodiments, the spatial gap between rail and ICM can be greater or less than 0.5 mm. In other embodiments, ICM  80  and rail  100  can overlap in different configurations. E.g., in one embodiment, rail  100  is inserted in the ICM  80 . 
     After ICM  80  and rail  100  are placed in an overlapping configuration, pressure is applied to the rail and/or ICM, as shown in  FIG. 6 . This is part of a two-step crimping process—(i) forming reservoirs in the ICM and then (ii) crimping the cross member with compatible crimps. In  FIG. 6 , there is a stamp press  150  having a mandrel  160  configured to form crimps  130  in the rail  100  and/or ICM  80 . Crimps  130  in the rail  100  are formed to match crimps or reservoirs  110  on ICM  80 . Crimps  130  act as a secondary mechanical interlock between rail  100  and interconnecting member  80  in this embodiment. The press  150  is configured to evenly distribute the adhesive between the rail  100  and ICM  80 . In this embodiment, the press  150  is configured to apply pressure to the cross rail  100  and ICM  80  so as to cause adhesive to ooze out of the reservoirs of the ICM. Adhesive is spread between the outer surface of the ICM and the inner surface of the rail  100  to form a joint between the two members. Rail  100  has four sets of two crimps  130  formed on each side of the outer surface of rail. Rail  100  and ICM  80  are rotated in 90 degree iterations between each press. 
     The finished assembly of the ICM  80  and rail  100  is shown in  FIG. 7-8 . After, the pressing process, adhesive  120  seeps out of one end of the rail  100  and one end of the ICM  80 . As shown in  FIG. 7 , adhesive  120  is squeezed in the crimping process. Adhesive  120  seeped out of the end of rail  100  to overflow on the outside of the ICM and rail, thereby forming a barrier between the cross rail  100  and ICM  80  joint and the surrounding environment.  FIG. 8  is a cross-section in the rail  100  taken from the inside the rail looking toward the side rail  20  (of  FIG. 2 ). As shown in  FIG. 8 , adhesive  120  is squeezed in the crimping process so as to seep out of an end of ICM  80 . Adhesive  120  that seeps out of end of the ICM  80  overflows on the inside of the rail, thereby forming a barrier between the rail and ICM joint and the surrounding environment on an inside surface as well. 
     Another exemplary support frame assembly  200  is partially shown and discussed with respect to  FIGS. 9-14 . Shown is a method of manufacturing the support frame assembly  200 , which is a vehicle cross-member assembly. The method includes the steps of: (1) adding adhesive to an adhesive reservoir in an interconnecting member, as shown and discussed with respect to  FIG. 9-11 ; (2) overlapping the cross rail and the interconnecting member, e.g., as shown in  FIG. 12 ; (3) crimping the overlapped ICM and rail; and (4) welding the interconnecting member to a side rail in a position perpendicular to the second rail, as shown in  FIG. 2 . 
     With respect to the first step, adding adhesive to an adhesive reservoir in the interconnecting member, this step is shown in  FIG. 9 . An adhesive applicator  210  includes a tip  220  marked at “M” for filling each reservoir  230  in an interconnecting member  240  to a desired level. In  FIG. 9 , an operator, I, is shown with the adhesive applicator  210  in one hand. ICM  240  includes at least three adhesive reservoirs  230  on each surface in this configuration. Adhesive  250  is inserted in the reservoirs. Adhesive  250  is also applied at a midpoint ( 280 ), 360 degrees around an outer surface of interconnecting member  240 . The ICM  240  with adhesive  250  is also illustrated in  FIG. 11 . 
     In this embodiment, additional adhesive  250  is applied to the inner walls of rail  270 , as shown in  FIG. 10 . Adhesive  250  is longitudinally applied along corners  290  of cross rail  270 , as shown in  FIG. 10 .  FIG. 10  is a cross-section view of the rail  270  pre-assembly with ICM  240 . 
     Once the adhesive  250  is applied, the operator moves to the next step, as shown in  FIG. 12 . The rail  270  and interconnecting member  240  are positioned in an overlapping configuration, as shown in  FIG. 12 . In this embodiment, ICM  240  is inserted in the rail  270 . After ICM  240  and rail  270  are placed in an overlapping configuration, pressure is applied to the rail  270  and ICM  240 . The press is configured to evenly distribute the adhesive between the rail and ICM by squeezing the adhesive out of the reservoirs and to create matching crimps between the rail and ICM for interlocking the two parts. Rail  270  has four sets of three crimps  260  formed on each side of the outer surface of rail. In this embodiment, the adhesive used is an epoxy (e.g., a two-part epoxy). Alternative one-part epoxies or other adhesives can also be used. 
     ICM  240  includes an optional reservoir  230 —as exposed in FIGS.  9  and  11 —that can be filled with adhesive or left unfilled (e.g., as shown in  FIG. 9 ). Reservoir  230  can be filled, for example, for more overlapping or stronger joints. In those embodiments, ICM  240  is inserted farther into cross rail  270  and three reservoirs on each side of the rail are filled to link ICM and cross rail. The use of optional reservoirs allows for commonality of parts for the cross rails and ICMs between different vehicle platforms. 
     After, the pressing process, adhesive  250  seeps out of one end of the rail  270  and one end of the ICM  240 . As shown in  FIG. 13 , adhesive  250  is squeezed in a crimping process so as to seep out of an end of ICM  240 . Adhesive  250  that seeps out of the ends of rail and ICM forms a barrier between the rail  270  and ICM  240  joint and the surrounding environment on the inside surface and outside surface as well. Different types of adhesives can be used to create barriers of different kinds. In the illustrated embodiment of  FIG. 13  a less viscous adhesive is used than in the embodiment of  FIG. 8 , for example, thus a thicker barrier is formed by the overflow of adhesive on the exterior of the ICM and in the interior of the rail. 
       FIG. 14  illustrates a cross-section in the support frame assembly  200  of  FIG. 12  at line  14 - 14  shown therein. As shown, adhesive  250  is completely filled between the ICM  240  and rail  270  at all four corners through the overlap length. Rail  270  is journaled onto the ICM  240 . Adhesive  250  is evenly distributed at the shown cross-section and the entire overlap as well. 
     Now with reference to  FIGS. 15-16  there is shown another exemplary embodiment of a support frame assembly  500 .  FIGS. 15-16  show partial perspective views of the support frame  500 . The support frame (or support frame assembly)  500  has rails  510 ,  520  composed of different materials. The material used for side rail  510  is not weld compatible with the material used for the cross-member. In this embodiment, the side rail  510  is composed of steel and the rail  520  is made of aluminum. Shown is an interconnecting member  530  formed with the side rail  510 . Interconnecting  530  is casted with side rail  510  in this embodiment. In other embodiments ICM  530  is, e.g., welded to rail  510 . Interconnecting member  530  is a steel tube. As shown in  FIGS. 15 and 16 , the rail  520  has a series of recesses or reservoirs  540  formed on the outer surface of the rail  520 . Reservoirs  540  are oblong in shape and configured to hold adhesive therein. Different types of adhesives can be used including e.g., resins or two-way epoxies. 
     The support frame assembly of  FIGS. 15-16  is manufactured using a method of manufacture as described hereinbelow. A method of manufacturing a vehicle cross-member assembly includes: adding adhesive to an adhesive reservoir in a rail; overlapping an interconnecting member with the rail by inserting the rail inside of the interconnecting member; performing a second crimping to distribute the adhesive and create the interlock between the two members; and, if needed, welding the interconnecting member to a side rail in a position perpendicular to the side rail, the side rail composed of a different material than the cross-member rail. 
     In another embodiment, as shown in  FIG. 17 , an interconnecting member fits inside of the rail  550 . The interconnecting member can include a series of complementary reservoirs formed on the outer surface of interconnecting member, e.g.,  230 , as shown in  FIG. 9 . A second crimping is performed on the rail  550  after the assembly to form protrusions. Complementary reservoirs and protrusions are located at the same positions to create mechanical interlocks between the two members. The interlock can also be created by a single step crimping on the interconnector-rail assembly without pre-existing protrusions. 
     Reservoirs can be any combination of recesses, protrusions, or a recess with protrusion and so forth. Reservoirs can be formed using known forming procedures (e.g., stamping, hydroforming, or die casting). Additionally, any of the aforementioned assembly or forming process steps can be executed by an operator, automated machine or a combination of the two. 
     Those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.