Abstract:
A weld includes a first component and a second component. The first component includes a fay surface with one or more grooves. The second component includes a surface that is configured to mate with the fay surface of the first component. The fay surface of the first component and the surface of the second component form a friction weld when the two surfaces are mated together and relative motion between the first component and the second component generates heat through mechanical friction between the two components.

Description:
RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 62/182,983, filed on Jun. 22, 2015, the entire contents of which are incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates to weld. More specifically, the present disclosure relates to a friction weld. 
       BACKGROUND 
       [0003]    The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. 
         [0004]    In a typical motor vehicle, certain components are welded together. Some welds involve components made of different alloys. For example, a lighter alloy such as aluminum or magnesium may be joined with a heavier alloy such as steel. Because of the physical and metallurgical property differences between these alloys, the joint strength may not be strong enough for certain applications. Specifically, brittle intermetallic compound formation and high residual stresses in the weld joint resulting from the use of alloys with different properties may limit the joint strength. 
         [0005]    Accordingly, there is a need for a weld that joins alloys with different metallurgical and physical properties with a higher joint strength. 
       SUMMARY 
       [0006]    In one aspect, a weld includes a first component and a second component. The first component includes a fay surface with one or more grooves. The second component includes a surface that is configured to mate with the fay surface of the first component. The fay surface of the first component and the surface of the second component forms a friction weld when the two surfaces are mated together and relative motion between the first component and the second component generates heat through mechanical friction between the two components. 
         [0007]    In another aspect, an assembly with a first component and a second component includes a fay surface with one or more grooves on the first component, and a surface on the second component that mates with the fay surface of the first component. The fay surface of the first component and the surface of the second component form a friction weld when the two surfaces are mated together and relative motion between the first component and the second component generates heat through mechanical friction between the two components. 
         [0008]    One or more of the following features may also be included in any of the above aspects: the one or more grooves has a depth, d; the one or more grooves is a plurality of grooves; each of the plurality of grooves has the same depth, d; each of the plurality of grooves has a different depth, d; each of the plurality of grooves has the same width, w; each of the plurality of grooves has a different width, w; the fay surface is characterized by an inner angle, α, and an outer angle, β; the inner angle, α, is between 0° to about 45°, and the outer angle, β, is between 0° to about 45°; and the fay surface includes one or more radial notches. 
         [0009]    In yet another aspect, an assembly with a first component and a second component joined together by a friction weld includes a fay surface with a plurality of grooves on the first component, and a fay surface with a plurality of groove on second component that mates with the fay surface of the first component. The fay surface of the first component and the fay surface of the second component form a friction weld when the two surfaces are mated together and relative motion between the first component and the second component generates heat through mechanical friction between the two components. This aspect may be further characterized by the following feature: each of the plurality of grooves on the first surface and on the second surface has the same depth, d, and each of the plurality of grooves on the first surface and on the second surface has the same width, d. 
         [0010]    Further features, advantages, and areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0011]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the views. In the drawings: 
           [0012]      FIG. 1A  is a schematic diagram of a rotational friction welding system; 
           [0013]      FIG. 1B  is side view of two components welded together with the system shown in  FIG. 1A ; 
           [0014]      FIG. 2A  is a side view of two components joined together with a rotational friction weld in accordance with the principles of the present invention; 
           [0015]      FIG. 2B  is a close-up view of the weld between the two components shown in  FIG. 2A  in accordance with the principles of the present invention; 
           [0016]      FIG. 2C  is a perspective view of one of the components shown in  FIG. 2A  in accordance with the principles of the present invention; 
           [0017]      FIG. 2D  is a close-up view of a fay surface of the component shown in  FIG. 2C  in accordance with the principles of the present invention; 
           [0018]      FIG. 2E  is a cross-sectional view of the fay surface shown in  FIG. 2D  in accordance with the principles of the present invention; 
           [0019]      FIG. 3A  is a side view of two components joined together with another rotational friction weld in accordance with the principles of the present invention; 
           [0020]      FIG. 3B  is a close-up view of the weld between the two components shown in  FIG. 3A  in accordance with the principles of the present invention; 
           [0021]      FIG. 3C  is a perspective view of one of the components shown in  FIG. 3A  in accordance with the principles of the present invention; 
           [0022]      FIG. 3D  is a close-up view of a fay surface of the component shown in  FIG. 3C  in accordance with the principles of the present invention; 
           [0023]      FIG. 3E  is a cross-sectional view of the fay surface shown in  FIG. 3D  in accordance with the principles of the present invention; 
           [0024]      FIG. 4A  is a perspective a component with a fay surface in accordance with the principles of the present invention; and 
           [0025]      FIG. 4B  is a close-up view of the fay surface shown in  FIG. 4A  in accordance with the principles of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
         [0027]    Referring now to the drawings, a rotational friction weld system is shown in  FIG. 1A  at  10 . The system  10  includes a motor  12  that rotates a rotating chuck  16 . A brake  14  is employed to control the rotational speed of the rotating chuck  16 . The system  10  further includes a non-rotating chuck  18  coupled to a hydraulic cylinder  24 . 
         [0028]    When the system  10  is in use, the rotating chuck  16  holds a first work piece or component  20  and the non-rotating chuck  18  holds a second work piece or component  22 . The first and second work pieces are made of dissimilar materials. For example, in certain arrangements the first work piece  20  is a steel gear and the second work piece  22  is an aluminum clutch shell. 
         [0029]    The motor  12  spins the rotating chuck  16  and hence the first work piece  20  at a high rate of rotation. When the first work piece  20  is spinning at the proper speed, the hydraulic cylinder  24  moves the non-rotating chuck  18  and hence the second work piece  22  towards the first work piece  20  in the direction of the arrow  26 . Accordingly, the two work pieces  20  and  22  are forced together under pressure to form a frictional weld that joins the two work pieces together as shown in  FIG. 1B . The spinning is stopped to allow the weld to set. In conventional frictional weld systems, the physical and metallurgical property differences between the different alloys results in a weakened weld. In particular, brittle intermetallic compound formation (such as, for example, Al 5 Fe 2 , Al 2 Fe, FeAl, Fe 3 Al and Al 6 Fe) and high residual stresses limit the joint strength between the two work pieces. 
         [0030]    Turning now to  FIGS. 2A and 2B , there is shown a frictional weld  124  formed between a first work piece  120  and a second work piece  122  in accordance with the principles of the present invention. The two work pieces are generally made of dissimilar materials. For example, the first work piece  120  can be made of steel and the second work piece  122  can be made of aluminum or magnesium. Moreover, the first work piece  120  can be a gear with a set of teeth  126  as illustrated in  FIG. 2C . 
         [0031]    Referring further to  FIGS. 2D and 2E , the first work piece  120  includes a fay surface  128  with a set of grooves  130  that mates with a corresponding surface of the second work piece  122 . The set of grooves  130  can be just one groove or a plurality of grooves. In the example shown in  FIGS. 2C, 2D and 2E , the set of grooves  130  includes four grooves. Each groove has a depth, d, and a width, w. The depths of each groove can be the same or they can all be different. The widths of each groove can be the same or they can all be different. In various arrangements, the groove depth, d, can be between 0 to about 3 mm and the width, w, can be between about 0.2 to 2 mm. The fay surface  128  is characterized by an inner angle, α, and an outer angle, β. The inner angle, α, can vary between 0° to about 45°, and the outer angle, β, can also vary between 0° to about 45°. 
         [0032]    When the first work piece  120  and the second work piece  122  are joined together by a rotational friction weld process, the softer alloy of the second work piece  122  is pushed into the grooves  130  of the first work piece  120 . The use of the grooves  130  increases joint strength of the weld  124  at the interface between the work pieces  120 ,  122  by increasing the joining area, reducing residual stresses by better stress distribution and adding mechanical bonding between the work pieces in addition to metallurgical bonding of the two alloys. Note, that the second work piece  122  may also include a grooved fay surface as well that mates with the fay surface  128  of the first work piece  120 . The fay surface of the second work piece  122  can be angled or unangled. 
         [0033]    Referring now to  FIGS. 3A and 3B , there is shown a frictional weld  224  formed between a first work piece  220  and a second work piece  222  in accordance with the principles of the present invention. The two work pieces are generally made of dissimilar materials. For example, the first work piece  220  can be made of steel and the second work piece  222  can be made of aluminum or magnesium. Moreover, the first work piece  220  can be a gear with a set of teeth  226  as illustrated in  FIG. 3C . 
         [0034]    Referring further to  FIGS. 3D and 3E , the first work piece  220  includes a fay surface  228  with a set of grooves  230  that mates with a corresponding surface of the second work piece  222 . The set of grooves  230  can be just one groove or a plurality of grooves. In the example shown in  FIGS. 3C, 3D and 3E , the set of grooves  230  includes four grooves. Each groove has a depth, d, and a width, w. The depths of each groove can be the same or they can all be different. The widths of each groove can be the same or they can all be different. In various arrangements, the groove depth, d, can be between 0 to about 3 mm and the width, w, can be between about 0.2 to 2 mm. The fay surface  128  is characterized by a flat surface. 
         [0035]    When the first work piece  220  and the second work piece  222  are joined together by a rotational friction weld process, the softer alloy of the second work piece  222  is pushed into the grooves  230  of the first work piece  220 . The use of the grooves  230  increases joint strength of the weld  224  at the interface between the two work pieces  220 ,  222  by increasing the joining area, reducing residual stresses by better stress distribution and adding mechanical bonding between the work pieces in addition to metallurgical bonding of the two alloys. Note, that the second work piece  222  may also include a grooved fay surface as well that mates with the fay surface  228  of the first work piece  220 . 
         [0036]    Referring now to  FIGS. 4A and 4B , there is shown another work piece  320  with a fay surface  328  in accordance with the principles of the present invention. The work piece  320  can be a gear with a set of teeth  326 . 
         [0037]    The work piece  320  includes a fay surface  328  with a set of grooves  330  that mates with a corresponding surface of a second work piece similar to any of the second work pieces described previously. The set of grooves  330  can be just one groove or a plurality of grooves. Each groove of the set of grooves  330  has a depth, d, and a width, w, as described above. The depths of each groove can be the same or they can all be different. The widths of each groove can be the same or they can all be different. The fay surface  328  also includes radial notches  332  that enhances the joining of the work piece  320  to a corresponding second work piece. 
         [0038]    When the work piece  320  and a second work piece are joined together by a rotational friction weld process, the softer alloy of the second work piece is pushed into the grooves  330  and the radial notches  332  of the work piece  320 . The use of the grooves  330  and the radial notches increases joint strength of the weld at the interface between the two work pieces by increasing the joining area, reducing residual stresses by better stress distribution and adding mechanical bonding between the work pieces in addition to metallurgical bonding of the two alloys. Note, that the fay surface  320  may have angled surface like those of fay surface  120  or the fay surface  220  discussed above. 
         [0039]    The description of the invention is merely exemplary in nature and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.