Patent Publication Number: US-8528187-B2

Title: Method and apparatus for joining multiple components

Description:
TECHNICAL FIELD 
     The invention relates to a method and an apparatus for joining multiple components. 
     BACKGROUND 
     Various processes and mechanisms are available in manufacturing for linking or joining various components. A specific joining process and/or mechanism is typically selected based on the materials of the components sought to be joined and the operating conditions that the structure formed from the joined components will be asked to endure. Additionally, a specific joining process and/or mechanism may be selected based on whether the subject components are sought to be joined permanently or are required to be separable. 
     Vehicle structures are commonly formed from different types and grades of various materials such as steel, aluminum, magnesium, and plastic. Frequently, additional reinforcing members are used to buttress the vehicle structure, as well as for supporting various chassis and powertrain subsystems. Joining processes for forming vehicle structures and additional reinforcing/supporting members are typically selected with consideration given to at least some of the factors noted above. Common joining processes for vehicle structures include the use of welding, gluing, and various mechanical fasteners. 
     SUMMARY 
     A method of joining multiple components includes stacking the components vertically. Each component includes two opposite substantially planar surfaces that are arranged in a column when the components are stacked. The method also includes placing the stacked components in a clinch-crimping apparatus having a first punch, a second punch, and a crimping element. The method also includes displacing or upsetting a section of the substantially planar surfaces of the stacked components by driving the first punch in a first direction that is substantially perpendicular to the substantially planar surfaces. The method additionally includes retracting or pulling the first punch away from the displaced section and crimping the displaced section by the crimping element to form a crush initiator. The method additionally includes disengaging the crimping element from the crimped, displaced section. Furthermore, the method includes clinching, collapsing, or crushing the crimped, displaced section by driving the second punch in a second direction that is opposite to the first direction. 
     The clinch-crimping apparatus may include an upper die configured to house the first punch and a lower die configured to house the second punch and the crimping element. In such a case, the upper die may be configured to apply a force to hold the stacked components between the first and second dies. 
     The method may also include controlling the force applied by the upper die such that the first punch displaces the section of the substantially planar surfaces of the stacked components for a desired distance without failure of the section. 
     The crimping element may also include a plurality of teeth, such that the crimping of the displaced section of the substantially planar surfaces may include using the plurality of teeth. 
     The lower die may include a plurality of movable sections and each of the plurality of movable sections may include at least one of the plurality of teeth. In such a case, the crimping of the displaced section and the disengaging of the crimping element may include respectively engaging with and disengaging from the displaced section the plurality of movable sections. 
     The lower die may include an actuating mechanism. In such a case, the method may include selectively engaging and disengaging the plurality of teeth using the actuating mechanism. 
     The first punch may include a plurality of grooves. In such a case, the method may additionally include clearing the crimped, displaced section of the substantially planar surfaces of the stacked components using the grooves when the first punch is retracted. 
     The method may additionally include driving the first and the second punches using a servomotor. 
     The method may additionally include locally heating the section of the substantially planar surfaces of the stacked components to increase the formability of the stacked components. 
     The stacked components may be sheets of at least one of steel, aluminum, and magnesium. 
     A clinch-crimping apparatus configured to perform the above method is also disclosed. 
     The above features and advantages and other features and advantages of the present invention 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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic illustration of a cross-section of a clinch-crimping apparatus when stacked components are being loaded in to the apparatus for being joined, with the apparatus including a heating element for locally heating a section of the stacked components; 
         FIG. 2  is a schematic illustration of a cross-section of the clinch-crimping apparatus shown in  FIG. 1 , with the apparatus being shown as the first punch displaces the section of the stacked components; 
         FIG. 3  is a schematic illustration of a cross-section of the clinch-crimping apparatus shown in  FIG. 1 , with the apparatus being shown employing a plurality of movable lower die sections during the crimping stage of the joining process as the first punch being retracted; 
         FIG. 4  is a schematic illustration of a cross-section of the clinch-crimping apparatus shown in  FIG. 1 , with the apparatus being shown as the plurality of movable lower die sections is retracted following the crimping stage of the joining process; 
         FIG. 5  is a schematic illustration of a cross-section of the clinch-crimping apparatus, with the apparatus being shown employing a first punch having a plurality of grooves configured to clear a plurality of crimping teeth and a teeth actuating mechanism during the crimping stage of the joining process; 
         FIG. 6  schematic illustration of a cross-section of the clinch-crimping apparatus shown in  FIG. 5 , with the apparatus being shown as the teeth actuating mechanism is being retracted following the crimping stage of the joining process; 
         FIG. 7  is a schematic illustration of a cross-section of the clinch-crimping apparatus shown in  FIG. 1 , with the apparatus being shown during the clinching stage of the joining process; 
         FIG. 8  illustrates a cross-section of the displaced section after the stacked components have been clinch-crimped by the clinch-crimping apparatus; and 
         FIG. 9  is a flow chart illustrating a method of joining multiple components via the clinch-crimping apparatus. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings in which like elements are identified with identical numerals throughout,  FIGS. 1-7  illustrate a clinch-crimping apparatus  10  for joining components  14  and  16 , which are shown as two vertically stacked sheets of material. The components  14  and  16  may each be formed from a malleable material such as steel, aluminum, magnesium, or a polymer compound. Additionally, the material of the component  14  may be dissimilar from the material of the component  16  and still be reliably joined by the clinch-crimping apparatus  10 . 
     Although components  14  and  16  are shown as two sheets of material, each of the components may also have a largely variable shape that additionally includes two opposite, substantially planar surfaces. In particular, the component  14  includes substantially planar surfaces  18  and  20 , while the component  16  includes substantially planar surfaces  22  and  24 . When such components  14  and  16  having largely variable shapes are stacked vertically, the substantially planar surfaces  18 ,  20 ,  22 , and  24  are arranged in a column prior to being joined, such that the planar surfaces  18 ,  20  are disposed directly below the planar surfaces  22 ,  24 . Accordingly, the clinch-crimping apparatus  10  may join the components  14 ,  16  at the substantially planar surfaces  18 ,  20 ,  22 , and  24  to ensure a robust assembly. 
     As shown in  FIG. 1 , the clinch-crimping apparatus  10  includes an upper die  26  having a first punch  28 , and a lower die  30  having a second punch  32  and a crimping element  34 . In order to be joined by the clinch-crimping apparatus  10 , the stacked components  14  and  16  are placed between the upper die  26  and the lower die  30 . The upper die  26  is configured to apply a force to the stacked components  14 ,  16  and against the lower die  30 , in order to hold the stacked components in the clinch-crimping apparatus  10 . 
     The first punch  28  is configured to be driven in a first direction  29  (as shown in  FIG. 2 ) that is substantially perpendicular to the substantially planar surfaces  18 ,  20 ,  22 , and  24  of the stacked components  14 ,  16 . Such actuation of the first punch  28  is configured to form a displaced section  36  of the substantially planar surfaces  18 ,  20 ,  22 , and  24 . The first punch  28  is also configured to retract into the upper die  26  following the desired forming of the displaced section  36 . 
     The force applied by the upper die  26  may be varied, such that the first punch  28  displaces the material of the stacked components  14 ,  16  for a desired distance, in order to form the displaced section  36  without failure of the section. Variably controlling the force applied by the upper die  26  permits the first punch  28  to travel deeper into the lower die  30  as additional material of the stacked components  14 ,  16  is carried into the lower die  30 . Such variable force capability may be especially useful in forming the displaced section  36  from materials having tensile strength that is lower as compared to steel, for example magnesium. 
     The crimping element  34  is configured to crimp the displaced section  36  of the stacked components  14 ,  16  to form a crush initiator on the surface of the displaced section. In general, a crush initiator is a preliminary deformation generated on a surface of a structure, such that in the event of anticipated loading the structure will commence to collapse at the deformation in a predictable manner. As shown in  FIGS. 1-7 , the crimping element  34  includes a plurality of teeth  38  that are configured to dimple the displaced section  36 , thus forming the crush initiator. The teeth  38  are movable generally in parallel relative to the surfaces  18 ,  20 ,  22 , and  24  of the stacked components  14 ,  16  in order to dimple the surface of the displaced section  36  and then be retracted. The teeth  38  may be movable by a variety of mechanisms in order to crimp the surface of the displaced section  36 . 
     As shown in  FIGS. 4 and 7 , the lower die  30  may include a plurality of movable lower sections  40  for moving the teeth  38  to crimp the displaced section  36 . In such a case, at least one of the plurality of teeth  38  is operatively connected to each one of the plurality of sections  40 , wherein each one of the plurality of sections is configured to be selectively engaged with and disengage from the displaced section  36 . As an alternative example, the lower die  30  may include an actuating mechanism  42  configured to selectively engage the plurality of teeth  38  with and disengage the plurality of teeth from the displaced section  36 , as shown in  FIGS. 5-6 . The actuating mechanism  42  may be configured as a mechanical, electromechanical, or a hydraulic device. 
     Additionally, as shown in  FIGS. 5-6 , the first punch  28  may include a plurality of grooves  44  configured to clear the teeth  38  during the crimping stage of the clinch-crimping process. Furthermore, the plurality of grooves  44  serves to clear the previously crimped, displaced section  36  of the stacked components  14 ,  16  when the first punch  28  is retracted. Accordingly, the crimped, displaced section  36  is permitted to pass through the grooves  44 , thus allowing the first punch  28  to disengage the crimped, displaced section and withdraw into the upper die  26 . 
     As shown in  FIG. 7 , the second punch  32  is configured to clinch the previously crimped, displaced section  36  of the stacked components  14 ,  16  by being driven in a second direction  33  that is opposite to the first direction  29 . The clinching of the displaced section  36  crushes or collapses the displaced section along the crush initiator generated by the teeth  38  on the surface of the displaced section. The collapsed portion of the displaced section  36  forms a mushroom shape that effectively rivets the material of the stacked components  14 ,  16  onto itself. 
     As shown in  FIG. 4 , the clinch-crimping apparatus  10  may include a servomotor  46  configured to drive each of the first and the second punches  28 ,  32  in order to accomplish the clinch-crimping of the stacked components  14 ,  16  according to the above description. The servomotor  46  may be regulated by a controller  48  which is programmed with an algorithm for performing the subject clinch-crimping operation. 
     The clinch-crimping apparatus  10  may also include a device  50 , such as one or more strategically placed induction coils, that is configured to locally heat or anneal the substantially planar surfaces  18 ,  20 ,  22 ,  24  of the stacked components  14 ,  16  to increase the formability of the stacked components. The contemplated local heating may also be accomplished via a stream of fluid or air characterized by a temperature that is sufficiently elevated to anneal the substantially planar surfaces  18 ,  20 ,  22 ,  24  to improve the subject material&#39;s ductility. The device  50  may be brought in to locally heat the substantially planar surfaces  18 ,  20 ,  22 ,  24  via a specifically configured robot or an end-of-arm tooling (not shown). Such local heating of the section  36  may be particularly beneficial for clinch-crimping materials such as magnesium. The local heating of the substantially planar surfaces  18 ,  20 ,  22 ,  24  is intended to be performed prior to but close in time to when those surfaces are to be displaced by the first punch  28 . 
       FIG. 8  illustrates a cross-section of the displaced section  36  after the components  14  and  16  have been clinch-crimped by the clinch-crimping apparatus  10 . 
       FIG. 9  depicts a method  60  of joining multiple components. The method  60  is described herein with respect to joining the components  14  and  16  in the clinch-crimping apparatus  10  shown in  FIGS. 1-7 . Method  60  is equally applicable to having the stacked components  14  and  16  passed through a stationary clinch-crimping apparatus  10 , such as by a conveyor, as well as having the clinch-crimping apparatus being traversed over stationary stacked components, to generate multiple clinch-crimped joints on the components. 
     The method commences in frame  62  with stacking the components  14  and  16  vertically, wherein each component the substantially planar surfaces  18 ,  20 ,  22 , and  24  are arranged in a column. After frame  62 , the method proceeds to frame  64  with placing the stacked components  14  and  16  in the clinch-crimping apparatus  10 . Following frame  64 , the method advances to frame  66 , where it includes displacing the section  36  of the substantially planar surfaces  18 ,  20 ,  22 ,  24  by driving the first punch  28  in the first direction  29 . From frame  66 , the method proceeds to frame  68 , where the method includes retracting the first punch  28  from the displaced section  36 . 
     After the first punch  28  has been retracted from the displaced section  36 , the method advances to frame  70  where it includes crimping the displaced section  36  by the crimping element  34  to form a crush initiator on the surface of the displaced section. Following frame  70 , the method progresses to frame  72 , where it includes disengaging the crimping element  34  from the crimped, displaced section  36 . The method concludes in frame  74 , where it includes clinching the crimped, displaced section  36  by driving the second punch  32  in the second direction  33 . 
     While the best modes for carrying out the invention have been described in detail, 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.