BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view taken through apparatus of the invention for providing the metallic part connecting method thereof and the resultant metallic part assembly of the invention.
FIG. 2 is an axial view taken along the direction of line 2-2 in FIG. 1 to illustrate a first metallic part that is connected to a second metallic part by the apparatus and method.
FIG. 3 is a sectional view taken along the direction of line 2-2 to further illustrate the construction of the first metallic part.
FIG. 4 is a half sectional view illustrating the manner in which the second metallic part is flow formed around the first metallic part illustrated in FIGS. 2 and 3 to provide the metallic part assembly of the invention.
FIG. 5 is a partial axial view taken along the direction of line 5-5 in FIG. 4 to further illustrate the construction of the metallic part assembly.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference to FIG. 1 of the drawings, apparatus 10 for providing metallic part connection in accordance with the invention is utilized to perform the method thereof which provides the resultant metallic part assembly 12 shown in FIGS. 4 and 5. The metallic part connecting method, the apparatus 10 and the resultant metallic part assembly 12 will all be described in an integrated manner to facilitate an understanding of all aspects of the invention.
As shown in FIG. 1, the apparatus 10 includes a spindle 14 rotatable about a central axis A. The spindle 14 includes a headstock 16 that mounts a mandrel 18 and also includes a tailstock 20. First and second metallic parts 22 and 24 are mounted by the spindle 14 by axial clamping between the mandrel 18 and tailstock 20. Rotation of the spindle 14 thus rotates the first and second metallic parts 22 and 24 about the central axis A.
The first metallic part 22 as shown in FIGS. 2 and 3 has a generally annular shape and includes an outer locking formation 26 extending about the central axis A and provided by circumferentially spaced locking projections 28 that project radially in an outward direction. These locking projections 28 may be formed as gear teeth, splines or other projections such as between grooves formed in the inner metallic part.
As shown in FIG. 1, the apparatus also includes a flow former 30 that includes at least one flow forming tool 32. As actually shown, there are a plurality of such tools, most preferably three such tools spaced at 120 degrees from each other. Each flow forming tool 32 rotates about an associated axis a and is located outwardly from the central axis A adjacent the outer extremity of the mandrel 18. During the rotation of the first and second metallic parts 22 and 24 on the spindle 14 as described above, the rotating flow forming tools 32 are moved axially along the central axis as shown by arrows b to provide flow forming of the second metallic part 24 over the outer locking formation 26 of the first metallic part 22. This flow forming mechanically interlocks the first and second parts 22 and 24 to each other to thereby provide the part assembly 12 illustrated in FIGS. 4 and 5.
More specifically as shown in FIGS. 4 and 5, the second metallic part 24 has portions 24′ and 24″ that are located on axial opposite axial sides of the outer locking formation projections 28 (FIG. 4) of the first metallic part 22 and has radially inwardly extending portions 34 (FIG. 5) that are located circumferentially between the outer locking formation projections 28. Thus, both axial and circumferential innerconnection of the metallic parts to each other secures their fixed relationship to each other.
The first and second metallic parts 22 and 24 may be made from different types of metals such as steel, zinc, aluminum, etc., may have different heat treatments to provide the required properties for each part, may have different compositions to also provide the required properties for each part, may be formed from blanks made by different processes such as rolling, casting, forming and machining, and may be combinations of the former.
As shown in FIGS. 2 and 3, the first metallic part 22 is initially formed inward of its outer locking formation 26 to provide connection formations 34 which are illustrated as holes that may be machined or otherwise initially formed upon the manufacture of the part. Such connection formations can be more easily provided such as by machining before the flow form connection of the parts to each other as the part assembly. Often, the resultant part assembly construction cannot be provided by a unitary metallic component because the connection formations cannot be machined or otherwise provide in the part configurations involved.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.