Apparatus and method for joining vehicle frame components

An apparatus and method for joining two or more vehicle components together to form a joint in a vehicle body and frame assembly is disclosed. The frame assembly can include a pair of longitudinally extending side rails having a plurality of transverse cross members extending therebetween. At least one of the side rails includes a portion that is deformed inwardly to define a mounting projection that is sized to receive an end of one of the cross members therein. The mounting projection is preferably formed having a first relatively large diameter portion that is somewhat larger in diameter than the outer diameter of the end of the cross member and a second relatively small diameter portion that is only slightly larger in diameter than the outer diameter of the end of the cross member. An internal magnetic pulse welding inductor assembly is inserted within the cross member to generate an intense electromagnetic field. The presence of this electromagnetic field causes the end of the cross member to expand outwardly into engagement with the first and second portions of the mounting projection of the side rail at a high velocity. The high velocity impact of the end of the cross member with the mounting projection of the side rail causes some portions of the end of the cross member and the mounting projection of the side rail to weld or molecularly bond together, and causes other portions of the end of the cross member and the mounting projection of the side rail to mechanically interlock or engage one another to form a joint for the vehicle body and frame assembly.

BACKGROUND OF THE INVENTION
 This invention relates in general to vehicular body and frame assemblies.
 In particular, this invention relates to an apparatus and method for
 forming joints between various components, such as between side rails and
 cross members, in such a vehicle body and frame assembly.
 Many land vehicles in common use, such as automobiles, vans, and trucks,
 include a body and frame assembly that is supported upon a plurality of
 groundengaging wheels by a resilient suspension system. The structures of
 known body and frame assemblies can be divided into two general
 categories, namely, separate and unitized. In a typical separate body and
 frame assembly, the structural components of the body portion and the
 frame portion are separate and independent from one another. When
 assembled, the frame portion of the assembly is resiliently supported upon
 the vehicle wheels by the suspension system and serves as a platform upon
 which the body portion of the assembly and other components of the vehicle
 can be mounted. Separate body and frame assemblies of this general type
 are found in most older vehicles, but remain in common use today for many
 relatively large or specialized use modern vehicles, such as large vans,
 sport utility vehicles, and trucks. In a typical unitized body and frame
 assembly, the structural components of the body portion and the frame
 portion are combined into an integral unit that is resiliently supported
 upon the vehicle wheels by the suspension system. Unitized body and frame
 assemblies of this general type are found in many relatively small modern
 vehicles, such as automobiles and minivans.
 Each of these body and frame assemblies is composed of a plurality of
 individual vehicle frame components that are secured together. In the
 past, virtually all of these vehicle frame components have been
 manufactured from a metallic material. Steel has traditionally been the
 preferred material for manufacturing all of such vehicle frame components
 because of its relatively high strength, relatively low cost, and ease of
 manufacture. Vehicle frame components manufactured from traditional
 metallic materials have been secured together by conventional welding
 techniques. As is well known, conventional welding techniques involve the
 application of heat to localized areas of two metallic members, which
 results in a coalescence of the two metallic members. Such welding may or
 may not be performed with the application of pressure, and may or may not
 include the use of a filler metal. Although conventional welding
 techniques have functioned satisfactorily in the past, there are some
 drawbacks to the use thereof in joining metallic vehicle frame components
 together. First, as noted above, conventional welding techniques involve
 the application of heat to localized areas of the two metallic frame
 members. This application of heat can cause undesirable distortions and
 weaknesses to be introduced into the metallic components. Second, while
 conventional welding techniques are well suited for joining components
 that are formed from similar metallic materials, it has been found to be
 somewhat more difficult to adapt them for use in joining components formed
 from dissimilar metallic materials. Third, conventional welding techniques
 are not easily adapted for joining components that have different gauge
 thicknesses. Inasmuch as the production of vehicle frames is usually an
 high volume, low margin process, it would be desirable to provide an
 improved apparatus and method for permanently joining two or more metallic
 vehicle frame components that avoids the drawbacks of conventional welding
 techniques.
 SUMMARY OF THE INVENTION
 This invention relates to an improved apparatus and method for joining two
 or more vehicle components together to form a joint in a vehicle body and
 frame assembly. The frame assembly can include a pair of longitudinally
 extending side rails having a plurality of transverse cross members
 extending therebetween. At least one of the side rails includes a portion
 that is deformed inwardly to define a mounting projection that is sized to
 receive an end of one of the cross members therein. The mounting
 projection is preferably formed having a first relatively large diameter
 portion that is somewhat larger in diameter than the outer diameter of the
 end of the cross member and a second relatively small diameter portion
 that is only slightly larger in diameter than the outer diameter of the
 end of the cross member. An internal magnetic pulse welding inductor
 assembly is inserted within the cross member to generate an intense
 electromagnetic field. The presence of this electromagnetic field causes
 the end of the cross member to expand outwardly into engagement with the
 first and second portions of the mounting projection of the side rail at a
 high velocity. The high velocity impact of the end of the cross member
 with the mounting projection of the side rail causes some portions of the
 end of the cross member and the mounting projection of the side rail to
 weld or molecularly bond together, and causes other portions of the end of
 the cross member and the mounting projection of the side rail to
 mechanically interlock or engage one another to form a joint for the
 vehicle body and frame assembly.
 Various objects and advantages of this invention will become apparent to
 those skilled in the art from the following detailed description of the
 preferred embodiments, when read in light of the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Referring now to the drawings, there is schematically illustrated in FIG. 1
 a vehicle body and frame assembly, indicated generally at 10, that has
 been manufactured in accordance with the apparatus and method of this
 invention. The illustrated vehicle body and frame assembly 10 is a ladder
 frame assembly. However, it will be appreciated that the apparatus and
 method of this invention may be utilized in the manufacture of any type of
 vehicle body and frame assembly, such as a unitized body and frame
 assembly where the structural components of the body portion and the frame
 portion are combined into an integral unit.
 The illustrated ladder frame assembly 10 includes a pair of longitudinally
 extending side rails 11 and 12 having a plurality of transverse cross
 members 13, 14, and 15 extending therebetween. The side rails 11 and 12
 extend longitudinally along the length of the assembly 10 and are
 generally parallel to one another. Each of the illustrated side rails 11
 and 12 is formed from a single, unitary member that extends along the
 entire length of the assembly 10. However, it will be appreciated that the
 side rails 11 and 12 may extend for only a portion of the length of the
 frame assembly 10. Alternatively, either or both of the side rails 11 and
 12 may be formed from two or more individual side rail sections that are
 welded or secured together in any manner to form the side rails 11 and 12.
 The illustrated side rails 11 and 12 are formed from open channel
 structural members having a cross sectional shape that is generally
 C-shaped. However, the side rails 11 and 12 may be formed having any
 desired cross sectional shape. Furthermore, as will become apparent below,
 the side rails 11 and 12 may be formed from closed channel structural
 members having any desired cross sectional shape. The side rails 11 and 12
 may be formed from any desired material or group of materials.
 The cross members 13, 14, and 15 extend generally perpendicular to the side
 rails 11 and 12. The cross members 13, 14, and 15 are spaced apart from
 one another along the length of the assembly 10. The ends of the cross
 members 13, 14, and 15 are secured to the side rails 11 and 12 at
 respective joints, the structures of which will be described and
 illustrated in detail below. When secured to the side rails 11 and 12, the
 cross members 13, 14, and 15 provide desired rigidity to the assembly 10.
 Although three cross members 13, 14, and 15 are shown in FIG. 1, it will
 be appreciated that a greater or lesser number of such cross members may
 be provided. The illustrated cross members 13, 14, and 15 are formed from
 closed channel structural members having a generally circular cross
 sectional shape. However, the cross members 13, 14, and 15 may be formed
 having any desired cross sectional shape and may, if desired, be from open
 channel structural members. The cross members 13, 14, and 15 may also be
 formed from any desired material or group of materials.
 Referring now to FIG. 2, there is illustrated a first embodiment of a joint
 between one of the side rails 11 and one of the cross members 13
 illustrated in FIG. 1 prior to being joined together. As shown therein,
 the side rail 11 includes a central web 21 having upper and lower flanges
 22 and 23 extending therefrom. A portion of the web 21 is deformed
 inwardly to provide an opening defining a cross member mounting
 projection, indicated generally at 24. As will be explained in greater
 detail below, the mounting projection 24 is sized to receive an end of the
 cross member 13 therein to form a joint between the side rail 11 and the
 cross member 13. In the illustrated embodiment, the mounting projection 24
 is generally cylindrical in shape, corresponding to the generally
 cylindrical shape of the end of the cross member 13. However, it will be
 appreciated that the mounting projection 24 and the end of the cross
 member 13 may have any desired shapes.
 The mounting projection 24 is preferably formed having a first relatively
 large diameter portion 24a and a second relatively small diameter portion
 24b. The relatively large diameter portion 24a of the mounting projection
 24 is somewhat larger in diameter than the outer diameter of the end of
 the cross member 13, thus providing a relatively large annular gap
 therebetween, as shown in FIG. 2. The relatively small diameter portion
 24b of the mounting projection 24 is only slightly larger in diameter than
 the outer diameter of the end of the cross member 13, thus providing a
 relatively small annular gap therebetween, as shown in FIG. 2.
 An internal magnetic pulse welding inductor assembly, indicated generally
 at 25, is provided to connect the end of the cross member 13 to the
 mounting projection 24 of the side rail 11. The magnetic pulse welding
 inductor assembly 25 is generally conventional in the art and includes an
 electromagnetic coil 26 that is carried at the end of a movable support
 27. The coil 26 is composed of a winding of an electrical conductor having
 leads 26a and 26b that extend therefrom through a switch (not shown) to a
 source of electrical power (not shown). In a manner that is known in the
 art, when the switch is closed, a closed electrical circuit is formed
 through the leads 26a and 26b between the source of electrical power and
 the coil 26. As a result, electrical current flows through the coil 26,
 causing an intense electromagnetic field to be generated thereabout.
 The presence of this electromagnetic field causes the end of the cross
 member 13 to expand outwardly at a high velocity into engagement with the
 mounting projection 24 of the side rail 11. Such high velocity engagement
 causes some portions of the end of the cross member 13 and the mounting
 projection 24 to weld or molecularly bond together, while other portions
 of the end of the cross member 13 and the mounting projection 24
 mechanically interlock or engage one another, as shown in FIG. 3.
 Specifically, because of the relatively large size of the annular gap
 between the first portion of the end of the cross member 13 and the
 relatively large diameter portion 24a of the mounting projection 24, the
 generation of the electromagnetic field causes the first portion of the
 end of the cross member 13 to be accelerated throughout a relatively large
 distance to achieve a relatively high velocity. Because it is able to
 achieve this relatively high velocity, the outer surface of the first
 portion of the end of the cross member 13 will weld or molecularly bond
 with the inner surface of the relatively large diameter portion 24a of the
 mounting projection 24. However, because of the relatively small annular
 gap between the second portion of the end of 20 the cross member 13 and
 the relatively small diameter portion 24b of the mounting projection 24,
 the generation of the electromagnetic field causes the second portion of
 the end of the cross member 13 to be accelerated throughout a relatively
 small distance to achieve a relatively low velocity. Because it is unable
 to achieve a relatively high velocity, the outer surface of the second
 portion of the end of the cross member 13 will mechanically engage and
 interlock with the inner surface of the relatively small diameter portion
 24b of the mounting projection 24, but will not weld or molecularly bond
 therewith. Thus, first portions of the end of the cross member 13 and the
 mounting projection 24 are welded or molecularly bonded together, while
 second portions of the end of the cross member 13 and the mounting
 projection 24 mechanically interlock or engage one another.
 As mentioned above, the illustrated mounting projection 24 is generally
 cylindrical in shape, corresponding generally to the cylindrical shape of
 the end of the cross member 13. However, the mounting projection 24 and
 the end of the cross member 13 may have any desired shapes. For example,
 it may be desirable in some instances to form the mounting projection 24
 and the end of the cross member 13 having non-circular cross sectional
 shapes. Such non-circular cross sectional shapes would provide an
 additional measure of strength to the joint so as to resist twisting
 movement of the cross member 13 relative to the side rail 11 under the
 influence of torsional stresses that may be encountered during use.
 Referring now to FIG. 4, there is illustrated a second embodiment of a
 joint between a modified structure for one of the side rails 11' and one
 of the cross members 13 illustrated in FIG. 1 prior to being joined
 together. As shown therein, the modified side rail 11' is a closed channel
 structural member including first and second webs 31 and 32 having upper
 and lower flanges 33 and 34 extending therebetween. A portion of the first
 web 31 is deformed inwardly to provide an opening defining a first cross
 member mounting projection, indicated generally at 35, that is sized to
 receive a first portion of the end of the cross member 13 therein.
 Similarly, a portion of the second web 32 is deformed inwardly to provide
 an opening defining a second cross member mounting projection, indicated
 generally at 36, that is sized to receive a second portion of the end of
 the cross member 13 therein. In the illustrated embodiment, the mounting
 projections 35 and 36 are generally cylindrical in shape, corresponding
 generally to the cylindrical shape of the end of the cross member 13.
 However, it will be appreciated that the first and second mounting
 projections 35 and 36 and the end of the cross member 13 may have any
 desired shapes.
 The first mounting projection 35 is preferably formed having a first
 relatively large diameter portion 35a and a second relatively small
 diameter portion 35b. Similarly, the second mounting projection 36 is
 preferably formed having a first relatively large diameter portion 36a and
 a second relatively small diameter portion 36b. The relatively large
 diameter portions 35a and 35b of the mounting projections 35 and 36 are
 somewhat larger in diameter than the outer diameter of the corresponding
 portions of the end of the cross member 13, thus providing relatively
 large annular gaps therebetween, as shown in FIG. 4. The relatively small
 diameter portions 35b and 36b of the mounting projections 35 and 36 are
 only slightly larger in diameter than the outer diameter of the end of the
 cross member 13, thus providing relatively small annular gaps
 therebetween, as shown in FIG. 4.
 To form the joint, the magnetic pulse welding inductor assembly 25 is
 initially inserted within the end of the cross member 13 such that it is
 located within the first mounting portion 35 of the side rail 11'. Then,
 the coil 26 is connected to the source of electrical power so as to
 generate the intense electromagnetic field. In the same manner as
 described above, the generation of the electromagnetic field by the coil
 26 causes a first portion of the end of the cross member 13 and the first
 mounting projection 35 to weld or molecularly bond together, while a
 second portion of the end of the cross member 13 and the first mounting
 projection 35 mechanically interlock or engage one another, as shown in
 FIG. 5.
 Specifically, because of the relatively large annular gap between the first
 portion of the end of the cross member 13 and the relatively large
 diameter portion 35a of the first mounting projection 35, the generation
 of the electromagnetic field causes the first portion of the end of the
 cross member 13 to be accelerated throughout a relatively large distance
 to achieve a relatively high velocity. Because it is able to achieve this
 relatively high velocity, the outer surface of the first portion of the
 end of the cross member 13 will weld or molecularly bond with the inner
 surface of the relatively large diameter portion 35a of the first mounting
 projection 35. However, because of the relatively small annular gap
 between the second portion of the end of the cross member 13 and the
 relatively small diameter portion 35b of the first mounting projection 35,
 the generation of the electromagnetic field causes the second portion of
 the end of the cross member 13 to be accelerated throughout a relatively
 small distance to achieve a relatively low velocity. Because it is unable
 to achieve a relatively high velocity, the outer surface of the second
 portion of the end of the cross member 13 will mechanically engage and
 interlock with the inner surface of the relatively small diameter portion
 35b of the first mounting projection 35, but will not weld or molecularly
 bond therewith. Thus, the first portion of the end of the cross member 13
 and the first mounting projection 35 are welded or molecularly bonded
 together, while the second portion of the end of the cross member 13 and
 the first mounting projection 35 mechanically interlock or engage one
 another.
 If desired, the expansion of the cross member 13 additionally (or
 alternatively) result in the creation of a bulged portion 13a. The bulged
 portion 13a is formed immediately adjacent to and abuts the inner end of
 the relatively small diameter portion 35b of the first mounting projection
 35. Thus, the bulged portion 13a of the cross member 13 abuts and
 mechanically interlocks or engages the side rail 11 to prevent axial
 removal therefrom.
 Next, the magnetic pulse welding inductor assembly 25 is moved further
 within the end of the cross member 13 such that it is located within the
 second mounting portion 36 of the side rail 11'. Then, the coil 26 is
 connected to the source of electrical power so as to generate the intense
 electromagnetic field. In the same manner as described above, the
 generation of the electromagnetic field by the coil 26 causes a third
 portion of the cross member 13 and the second mounting projection 36 to
 weld or molecularly bond together, while a fourth portion of the cross
 member 13 and the second mounting projection 36 mechanically interlock or
 engage one another, as shown in FIG. 6. Specifically, because of the
 relatively large annular gap between the first portion of the end of the
 cross member 13 and the relatively large diameter portion 36a of the
 second mounting projection 36, the generation of the electromagnetic field
 causes the third portion of the end of the cross member 13 to be
 accelerated throughout a relatively large distance to achieve a relatively
 high velocity. Because it is able to achieve this relatively high
 velocity, the outer surface of the third portion of the end of the cross
 member 13 will weld or molecularly bond with the inner surface of the
 relatively large diameter portion 36a of the second mounting projection
 36. However, because of the relatively small annular gap between the
 second portion of the end of the cross member 13 and the relatively small
 diameter portion 36b of the second mounting projection 36, the generation
 of the electromagnetic field causes the fourth portion of the end of the
 cross member 13 to be accelerated throughout a relatively small distance
 to achieve a relatively low velocity. Because it is unable to achieve a
 relatively high velocity, the outer surface of the fourth portion of the
 end of the cross member 13 will mechanically engage and interlock with the
 inner surface of the relatively small diameter portion 36b of the second
 mounting projection 36, but will not weld or molecularly bond therewith.
 Thus, the third portion of the cross member 13 and the second mounting
 projection 36 are welded or molecularly bonded together, while the fourth
 portion of the cross member 13 and the second mounting projection 36
 mechanically interlock or engage one another.
 Similarly, the expansion of the cross member 13 can additionally (or
 alternatively) result in the creation of a second bulged portion 13b. The
 second bulged portion 13b is formed immediately adjacent to and abuts the
 inner end of the relatively small diameter portion 36b of the second
 mounting projection 36. Thus, the bulged portion 13a of the cross member
 13 abuts and mechanically interlocks or engages the side rail 11 to
 prevent axial removal therefrom.
 FIG. 7 is a sectional elevational view of the second embodiment of the
 joint illustrated in FIGS. 4, 5, and 6 prior to being joined together by a
 modified internal magnetic pulse welding inductor, indicated generally at
 25', in accordance with this invention. The modified magnetic pulse
 welding inductor assembly 25' is identical to the magnetic pulse welding
 inductor assembly 25 described above, except it includes an enlarged coil
 26' that is sufficiently large as to simultaneously cause the end of the
 cross member 13 to be connected to both the first and second mounting
 portions 35 and 36 of the side rail 11' in the manner described above. The
 expansion of the cross member 13 additionally (or alternatively) result in
 the creation of a single bulged portion 13c. The bulged portion 13c is
 formed between and abuts the inner ends of the relatively small diameter
 portions 35b and 36b of the first and second mounting projections 35 and
 36, respectively. Thus, the bulged portion 13c of the cross member 13
 abuts and mechanically interlocks or engages the side rail 11' to prevent
 axial removal therefrom.
 Referring now to FIG. 9, there is illustrated a third embodiment of a joint
 between a further modified structure for one of the side rails 11" and one
 of the cross members 13 illustrated in FIG. 1 prior to being joined
 together. As shown therein, the modified side rail 11' is a closed channel
 structural member including first and second webs 41 and 42 having upper
 and lower flanges 43 and 44 extending therebetween. A portion of the first
 web 41 is deformed outwardly to provide an opening defining a first cross
 member mounting projection 45 that is sized to receive a first portion of
 the end of the cross member 13 therein. Similarly, a portion of the second
 web 32 is deformed outwardly to provide an opening defining a second cross
 member mounting projection 46 that is sized to receive a second portion of
 the end of the cross member 13 therein. In the illustrated embodiment, the
 mounting projections 45 and 46 are generally cylindrical in shape,
 corresponding generally to the cylindrical shape of the end of the cross
 member 13. However, it will be appreciated that the first and second
 mounting projections 45 and 46 and the end of the cross member 13 may have
 any desired shapes. The first and second mounting projections 45 and 46
 are preferably somewhat larger in diameter than the outer diameter of the
 corresponding portions of the end of the cross member 13, thus providing
 relatively large annular gaps therebetween, as shown in FIG. 9.
 To form the joint, the magnetic pulse welding inductor assembly 25 is
 initially inserted within the end of the cross member 13 such that it is
 located within the first mounting portion 45 of the side rail 11'. Then,
 the coil 26 is connected to the source of electrical power so as to
 generate the intense electromagnetic field. In the same manner as
 described above, the generation of the electromagnetic field by the coil
 26 causes a first portion of the cross member 13 and the first mounting
 projection 45 to weld or molecularly bond together, while a second portion
 of the cross member 13 mechanically interlock or engage the web 41, as
 shown in FIG. 10. Specifically, because of the relatively large annular
 gap between the first portion of the end of the cross member 13 and the
 relatively large diameter first mounting projection 45, the generation of
 the electromagnetic field causes the first portion of the end of the cross
 member 13 to be accelerated throughout a relatively large distance to
 achieve a relatively high velocity. Because it is able to achieve this
 relatively high velocity, the outer surface of the first portion of the
 end of the cross member 13 will weld or molecularly bond with the inner
 surface of the first mounting projection 45. However, a second portion of
 the end of the cross member 13 is expanded within the interior of the side
 rail 11" to formed a bulged portion 13d. Thus, the first portion of the
 cross member 13 and the first mounting projection 45 are welded or
 molecularly bonded together, while the bulged portion 13d of the cross
 member 13 abuts and mechanically interlocks or engages the web 41.
 Next, the magnetic pulse welding inductor assembly 25 is moved further
 within the end of the cross member 13 such that it is located within the
 second mounting portion 46 of the side rail 11". Then, the coil 26 is
 connected to the source of electrical power so as to generate the intense
 electromagnetic field. In the same manner as described above, the
 generation of the electromagnetic field by the coil 26 causes a third
 portion of the cross member 13 and the second mounting projection 46 to
 weld or molecularly bond together, while a fourth portion of the cross
 member 13 mechanically interlocks or engages the web 42, as shown in FIG.
 11. Specifically, because of the relatively large annular gap between the
 first portion of the end of the cross member 13 and the relatively large
 diameter second mounting projection 46, the generation of the
 electromagnetic field causes the third portion of the end of the cross
 member 13 to be accelerated throughout a relatively large distance to
 achieve a relatively high velocity. Because it is able to achieve this
 relatively high velocity, the outer surface of the third portion of the
 end of the cross member 13 will weld or molecularly bond with inner
 surface of the second mounting projection 46. However, a second portion of
 the end of the cross member 13 is expanded within the interior of the side
 rail 11" to formed a second bulged portion 13e. Thus, the third portion of
 the cross member 13 and the first mounting projection 46 are welded or
 molecularly bonded together, while the second bulged portion 13e of the
 cross member 13 abuts and mechanically interlocks or engages the web 42.
 In accordance with the provisions of the patent statutes, the principle and
 mode of operation of this invention have been explained and illustrated in
 its preferred embodiment. However ,it must be understood that this
 invention may be practiced otherwise than as specifically explained and
 illustrated without departing from its spirit or scope.