METHOD FOR JOINING TWO COMPONENTS TOGETHER

BACKGROUND OF THE INVENTION

[0001 ] This invention relates in general to methods of joining two components together. In particular, this invention relates to an improved method of joining two components together by performing a first operation to deform one or both of the components into engagement with one another, then performing a second operation to permanently join the two components together.

[0002] In the manufacture of many different kinds of structures, it is often necessary to join two components together, either alone or as part of a larger assembly of components. For example, in the manufacture of vehicular frame assemblies, it is known to join two frame components, such as a side rail and a cross member, to form a joint therebetween to form part of a larger frame assembly. Also, in the manufacture of vehicular driveshaft assemblies, it is known to join two driveshaft components, such as a tube yoke and a driveshaft tube, to form a joint therebetween to form part of a larger driveshaft assembly. In many instances, it is desirable that the two components be permanently joined together, i.e., joined together in such a manner as to prevent them from becoming separated without causing damage thereto. [0003] A variety of methods are known in the art for joining two components, permanently or otherwise. Some of such joining methods are mechanical in nature. Mechanical joining methods usually involve the securement of the first and second components in physical contact with one another using a fastening mechanism, without any coalescence of the material that is used to form the first and second components. Examples of mechanical joining methods include riveting, bolting, clinching, and the like. Others of such joining methods are metallurgical in nature. Metallurgical joining methods usually involve the coalescence of the metallic material that is used to form either or both of the first and second components and may involve

the use of a filler material. Examples of metallurgical joining methods include welding, brazing, soldering, and the like.

[0004] Regardless of the specific joining method that is used, it has been found to be important that the two components be initially in close physical contact with one another before the joining method is performed in order to form a good quality joint. Such initial close physical contact not only facilitates the performance of the particular joining method that is being used, but also minimizes the amount of undesirable stresses that can be created in the two components after the joining method is completed.

[0005] In the past, this close physical contact between the two components has been obtained by the precise design and manufacture of the two individual components. For example, the first component was designed having an opening formed therethrough that defined an inner dimension, and the second component was designed having a surface that defined an outer dimension that was only slightly smaller than the inner dimension of the opening of the first component. This design allowed the second component to be initially inserted within the opening formed through the first component and be in close physical contact therewith, leaving only a minimum amount of space therebetween. Thereafter, the desired joining process (whether mechanical or metallurgical in nature) was performed to join the first and second components together.

[0006] Although this known method of joining first and second components is effective, it has been found to be somewhat time consuming and difficult to perform, particularly in the context of a high volume production situation. Thus, it would be desirable to provide an improved method of joining two components together by performing a first operation to deform one or both of the components into engagement with one another, then performing a second operation to join the two components together.

SUMMARY OF THE INVENTION

[0007] This invention relates to an improved method of joining two components together by performing a first operation to deform one or both of the components into engagement with one another, then performing a second operation to join the two components together. The first and second components are initially provided in an overlapping relationship. Then, a first operation is performed to deform the first component into engagement with the second component. The first operation can, for example, be magnetic pulse forming or swaging. Lastly, a second operation is performed to permanently join the first and second components together. The second operation can, for example, be a metallurgical joining method, such as welding, brazing, soldering, and the like, or a mechanical joining method, such as riveting, bolting, clinching, and the like.

[0008] Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Fig. 1 is a sectional elevational view of first and second components shown in a first step of being joined together in accordance with the method of this invention. [0010] Fig. 2 is a sectional elevational view of the first and second components illustrated in Fig. 1 shown in a second step of being joined together in accordance with the method of this invention.

[0011 ] Fig. 3 is a sectional elevational view of the first and second components illustrated in Fig. 2 shown in a third step of being joined together in accordance with the method of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0012] Referring now to the drawings, there is illustrated in Figs. 1 through 3 a method of joining first and second components 10 and 20, respectively, together in accordance with this invention. The first component 10 can, for example, be a side

rail that forms a first portion of a vehicular frame assembly, while the second component 20 can, for example, be a cross member that forms a second portion of such a vehicular frame assembly. However, the scope of this invention is not intended to be limited for use with the specific structures for the first and second components 10 and 20, respectively, illustrated in the drawings or, for that matter, for use with vehicular frame assemblies in general. On the contrary, as will become apparent below, this invention may be used in any desired environment for the purposes described below.

[0013] The illustrated first component 10 is an open channel structural member having a central web portion 10a that extends between upper and lower flange portions 10b. An opening is formed through the web portion 10a of the first component 10, defining an internal flange 10c. In the illustrated embodiment, the opening formed through the web portion 10a of the first component 10 is circular in shape, and the internal flange 10c is cylindrical in shape. However, the opening and the internal flange 10c may have any desired shape or shapes. The opening and the internal flange 10c define an internal dimension. In the illustrated embodiment, the first component 10 is formed from a metallic material. However, it will be appreciated that the first component 10 may be formed from any desired material. The second component 20 is a hollow cylindrical tube. However, the second component 20 may have any desired shape or shapes. In the illustrated embodiment, the second component 20 is formed from a metallic material. However, it will be appreciated that the second component 20 may be formed from any desired material. [0014] The outer surface of the second component 20 defines an external dimension that is somewhat smaller than the internal dimension defined by the opening and the internal flange 10c. As a result, a portion of the second component 20 can be initially inserted through the opening and the internal flange 10c formed in the first component 10, as shown in Fig. 1. Because of the difference between the external dimension defined by the outer surface of the second component 20 and the internal dimension defined by the opening and the internal flange 10c, the portion of the second component 20 can be easily inserted through the opening and the internal

flange 10c formed in the first component 10. However, as also shown in Fig. I ₃ this difference also creates a relatively large space or gap, indicated generally at 11 in Fig. 1, between the first component 10 and the second component 20. [0015] In a second step of the method of this invention illustrated in Fig. 2, a first operation is performed to deform one or both of the first and second components 10 and 20, respectively, into engagement with one another. In the illustrated embodiment, this first operation is a magnetic pulse forming operation. However, this first operation can be performed using any other desired process. Examples of such other processes include a variety of conventional deforming processes, such as swaging, for example.

[0016] To perform the illustrated magnetic pulse forming process, an inductor 30 is disposed within the end of the second component 20 disposed within the internal flange 10c of the first component. The inductor 30 is conventional in the art and forms a portion of a conventional magnetic pulse forming apparatus. Magnetic pulse forming is a well known process that can be used to deform one or more metallic workpieces to a desired shape. Typically, a magnetic pulse forming process is performed by initially disposing portions of first and second workpieces in an overlapping relationship. Then, an electromagnetic field is generated either within or about the overlapping portions of the first and second workpieces. When this occurs, a large pressure is exerted on one of the first and second workpieces, causing it to move toward the other of the first and second workpieces. If the electromagnetic field is generated about the exterior of the two workpieces, then the outer workpiece is deformed inwardly into engagement with the inner workpiece. If, on the other hand, the electromagnetic field is generated within the interior of the two workpieces, then the inner workpiece is deformed outwardly into engagement with the outer workpiece. [0017] In a magnetic pulse forming process, a relatively low intensity electromagnetic field is generated. As a result, the first workpiece impacts the second workpiece at a relatively small velocity, thereby causing the first workpiece merely to be deformed into conformance with the second workpiece. To generate the electromagnetic field that is used in the magnetic pulse forming process, the inductor

30 is provided. The inductor 30 is typically embodied as an electrical conductor that is wound into a coil and is positioned either about the exterior of the two workpieces or within the interior of the two workpieces. The inductor 30 is selectively connected by a switch through a pair of electrical conductors to a power supply. The power supply usually includes a source of electrical power that is connected a plurality of capacitors. The source of electrical power is initially connected to the plurality of capacitors so as to charge them to a predetermined voltage. Thereafter, when it is desired to perform the magnetic pulse forming process, the switch is closed so as to connect the plurality of capacitors through the pair of electrical conductors to the inductor 30 in a closed electrical circuit. When this occurs, a high magnitude pulse of electrical current is passed from the plurality of capacitors through the pair of electrical conductors and the inductor 30. As a result, the inductor 30 generates the electromagnetic field either about or within the two workpieces (depending upon where the inductor 30 is positioned) to perform the magnetic pulse forming process. After the capacitors have been discharged, the switch is opened to allow the source of electrical power to recharge the plurality of capacitors to the predetermined voltage in anticipation of the performance of the next magnetic pulse forming process. [0018] As shown in Fig. 2, after the completion of the magnetic pulse forming process, a portion 20a of the second component 20 has been deformed outwardly into engagement with the inner flange 10c of the first component. Thus, it can be seen that the gap 11 that previously existed between the portions of the first and second components 10 and 20, respectively, has been completely eliminated. Consequently, the portions of the first and second components 10 and 20, respectively, are in close physical contact with one another.

[0019] After the completion of the magnetic pulse forming process, a second operation is performed to join the first and second components 10 and 20, respectively, together as shown in Fig. 3. In the illustrated embodiment, this second operation is a conventional welding process that results in a weld 40 being formed between the opening and the inner flange 10c of the first component 10 and the enlarged end 20a of the second component 20. As a result of this welding process, the

first and second components 10 and 20, respectively, are permanently joined together. However, this second operation can be performed using any other desired process, including mechanical joining methods and metallurgical joining methods. Mechanical joining methods usually involve the securement of the first and second components in physical contact with one another using a fastening mechanism, without any coalescence of the material that is used to form the first and second components. Examples of mechanical joining methods include riveting, bolting, clinching, and the like. Metallurgical joining methods usually involve the coalescence of the metallic material that is used to form either or both of the first and second components and may involve the use of a filler material. Examples of metallurgical joining methods include welding, brazing, soldering, and the like.

[0020] In the embodiment of this invention described above and illustrated in the drawings, a portion of the second component 20 is deformed into engagement with the internal flange 10c of the first component 10. However, if desired, a portion of the first component 10 could be deformed into engagement with the second component 20. Alternatively, this invention contemplates that both of the first and second components 10 and 20, respectively, can be deformed into engagement with one another.

[0021 ] 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.