This invention relates in general to methods of manufacturing splined members, such as are commonly used in the driveshaft assemblies. In particular, this invention relates to an improved method of manufacturing a splined member for use in such a driveshaft assembly.
Drive train systems are widely used for generating power from a source and for transferring such power from the source to a driven mechanism. Frequently, the source generates rotational power, and such rotational power is transferred from the source to a rotatably driven mechanism. For example, in most land vehicles in use today, an engine/transmission assembly generates rotational power, and such rotational power is transferred from an output shaft of the engine/transmission assembly through a driveshaft assembly to an input shaft of an axle assembly so as to rotatably drive the wheels of the vehicle. To accomplish this, a typical driveshaft assembly includes a hollow cylindrical driveshaft tube having a pair of end fittings, such as a pair of tube yokes, secured to the front and rear ends thereof. The front end fitting forms a portion of a front universal joint that connects the output shaft of the engine/transmission assembly to the front end of the driveshaft tube. Similarly, the rear end fitting forms a portion of a rear universal joint that connects the rear end of the driveshaft tube to the input shaft of the axle assembly. The front and rear universal joints provide a rotational driving connection from the output shaft of the engine/transmission assembly through the driveshaft tube to the input shaft of the axle assembly, while accommodating a limited amount of angular misalignment between the rotational axes of these three shafts.
Not only must a typical drive train system accommodate a limited amount of angular misalignment between the source of rotational power and the rotatably driven device, but it must also typically accommodate a limited amount of relative axial movement therebetween. For example, in most vehicles, a small amount of relative axial movement frequently occurs between the engine/transmission assembly and the axle assembly when the suspension of the vehicle articulates during normal operation, such as when the vehicle is driven over a bumpy road. To address this, it is known to provide a slip joint in the driveshaft assembly. A typical slip joint includes first and second members that have respective structures formed thereon that cooperate with one another for concurrent rotational movement, while permitting a limited amount of axial movement to occur therebetween.
One type of slip joint commonly used in conventional driveshaft assemblies is a sliding spline type slip joint. A typical sliding spline type of slip joint includes male and female members having respective pluralities of splines formed thereon. The male member is generally cylindrical in shape and has a plurality of outwardly extending splines formed on the outer surface thereof. The male member may be formed integrally with or secured to an end of the driveshaft assembly described above. The female member, on the other hand, is generally hollow and cylindrical in shape and has a plurality of inwardly extending splines formed on the inner surface thereof. The female member may be formed integrally with or secured to a yoke that forms a portion of one of the universal joints described above. To assemble the slip joint, the male member is inserted within the female member such that the outwardly extending splines of the male member cooperate with the inwardly extending splines of the female member. As a result, the male and female members are connected together for concurrent rotational movement. However, the outwardly extending splines of the male member can slide relative to the inwardly extending splines of the female member to allow a limited amount of relative axial movement to occur between the engine/transmission assembly and the axle assembly of the drive train system.
In the past, the male and female splined members have usually been formed from steel, and the splines of such members have been manufactured by machining portions of such members so as to provide the desired splines. Although this method has been effective, the use of the machining process to form the splines has resulted in the generation of waste material, which is inefficient. Also, the use of the conventional machining process to form the splines can generate dimensional variances that result from normal manufacturing tolerances and practices. More recently, the male and female splined members have usually been formed from aluminum alloys having relatively low elongation factors, such as 6061-T6 aluminum. The use of these aluminum alloys has been found to be desirable because aluminum is much lighter in weight than steel. However, the use of the machining process to form the splines in the aluminum members still results in the generation of waste material and dimensional inaccuracies. Thus, it would be desirable to provide an improved method of manufacturing a splined member, such as for use in a vehicular driveshaft assembly, that avoids the generation of waste material and minimizes the amount of dimensional inaccuracies.
This invention relates to an improved method of manufacturing a splined member, such as for use in a vehicular driveshaft assembly, that avoids the generation of waste material and minimizes the amount of dimensional inaccuracies. A hollow cylindrical workpiece is initially provided from a material having a relatively high elongation characteristic. The material used to form the workpiece may be AA-5154 grade aluminum alloy having an elongation characteristic that is in the range of from about 20% to about 30%, preferably in the range of from about 22% to about 28%, and most preferably about 25%. A mandrel having a plurality of external splines is inserted within the workpiece, and the workpiece is deformed into engagement with the mandrel to form a splined member using a swaging process, such a rotary swaging or feed swaging. The splined member is thus formed having a plurality of internal splines and a cylindrical outer surface. The use of the swaging process avoids the generation of waste material. Also, dimensional accuracy is improved because the splined member is shaped in accordance with the precisely formed mandrel, which eliminates dimensional variations that can result from conventional machining practices.
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.
Referring now to the drawings, there is illustrated in
As shown in
The workpiece 10 is formed from a material having a relatively high elongation characteristic. As used herein, the term “elongation characteristic” is used to designate a factor that is representative of the amount of ductility of the material used to form the workpiece 10. The elongation factor varies directly with the amount of ductility of the material, i.e., the higher the elongation factor, the more ductile the material is, and vice versa. The elongation characteristic of the material used to form the workpiece 10 can be determined in any desired manner. For example, the elongation characteristic of the material can be determined empirically by initially providing a pair of marks at spaced apart locations on the outer surface of a piece of the material and measuring the distance therebetween. Then, the piece of the material is subjected to tensile forces, which causes it to elongate and increase the distance between the two marks. After a certain amount of such elongation has occurred, the piece of the material will fracture into two pieces. Following such fracture, the two pieces of the material are disposed adjacent to one another, and the length of the extension before the fracture occurred is measured as the distance between the two marks. By dividing the extended length between the two marks by the original length therebetween, the elongation factor can be expressed as a percentage of the original length.
As used herein, the term “relatively high elongation characteristic” is used to designate an elongation characteristic that is in the range of from about 20% to about 30%, preferably in the range of from about 22% to about 28%, and most preferably about 25%. The workpiece 10 is preferably formed from an aluminum alloy material having a relatively high elongation characteristic. One example of a material that has a relatively high elongation characteristic is AA-5154 grade aluminum alloy having an H112 temper and a generally uniform wall thickness of about one-quarter inch.
Alternatively, the workpiece 10 can be formed from a material having a relatively low elongation characteristic, but which is subjected to a softening process to provide it with a relatively high elongation characteristic. One well known softening process is a retrogression heat treatment process. Generally speaking, the retrogression heat treatment process is performed by rapidly heating the workpiece 10 to a sufficient temperature that provides for full or partial softening thereof, followed by relatively rapid cooling. Notwithstanding this cooling, the workpiece 10 retains the full or partial softening characteristics for at least a relatively short period of time. The deformation of the workpiece 10 is performed in the manner described below while the workpiece 10 retains the full or partial softening characteristics.
The illustrated mandrel 20 is generally cylindrical in shape, including a supporting shaft portion 21 and an end portion having a plurality of axially extending external splines 22 formed on the outer surface thereof. Preferably, the external splines 22 of the mandrel 20 define an outer diameter that is smaller than an inner diameter defined by the inner surface 12 of the workpiece 10. As a result, the mandrel 20 can be quickly and easily inserted co-axially within the workpiece 10, as shown in
Thus, the next step in the method is to deform a portion of the workpiece 10 about the axially extending external splines 22 of the mandrel 20, as shown in
Thereafter, the mandrel 20 is removed from the workpiece 10, as shown in
Next, portions of the splined member 16 can be machined or otherwise re-shaped to provide a variety of desired structures thereon. For example, as shown in
As shown in
As discussed above, one or more annular grooves 13b are formed in the outer surface of the deformed reduced diameter portion 13 of the female splined driveshaft component 50. These annular grooves 13b can be provided to facilitate the securement of a first end of a conventional flexible boot (not shown) about the open end of the deformed reduced diameter portion 13 of the female splined driveshaft component 50. A second end of such a flexible boot could also be secured to the outer surface of the male splined driveshaft component 60 to prevent dirt, water, and other contaminants from entering into the region of the cooperating splines 62 and 13a. To facilitate the securement of the second end of the flexible boot the outer surface of the male splined driveshaft component 60, one or more similar grooves (not shown) can also be formed in the outer surface of the male splined driveshaft component 60.
Although the method of this invention has been described and illustrated in the context of the formation of a female splined member, it will be appreciated that this invention can be used to form a male splined member as well. To accomplish this, the hollow cylindrical workpiece 10 could be inserted within a hollow cylindrical mandrel (not shown) having a plurality of axially extending internal splines formed on the inner surface thereof. The hollow cylindrical workpiece 10 could then be expanded outwardly, such as by using conventional magnetic pulse forming techniques, so as to form a male splined member having a plurality of axially extending external splines formed on the outer surface thereof.
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 embodiments. 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.
This application claims the benefit of U.S. Provisional Application No. 60/608,021, filed Sep. 8, 2004, the disclosure of which is incorporated herein by reference.
Number | Name | Date | Kind |
---|---|---|---|
3263474 | Pentland | Aug 1966 | A |
3566651 | Tlaker | Mar 1971 | A |
3643485 | Marcovitch | Feb 1972 | A |
3961513 | Stahly | Jun 1976 | A |
4093474 | Sperry et al. | Jun 1978 | A |
4470290 | Jungesjo | Sep 1984 | A |
5213250 | Simon | May 1993 | A |
5333775 | Bruggemann et al. | Aug 1994 | A |
5643093 | Breese | Jul 1997 | A |
5771737 | Yaegashi | Jun 1998 | A |
5829911 | Yokota et al. | Nov 1998 | A |
5981921 | Yablochnikov | Nov 1999 | A |
6001018 | Breese | Dec 1999 | A |
6033499 | Mitra | Mar 2000 | A |
6038901 | Stein et al. | Mar 2000 | A |
6257041 | Duggan | Jul 2001 | B1 |
6718811 | Drillon et al. | Apr 2004 | B2 |
6959476 | Li et al. | Nov 2005 | B2 |
7028404 | Poirier et al. | Apr 2006 | B1 |
7062834 | Patterson et al. | Jun 2006 | B2 |
20050257924 | Buchanan | Nov 2005 | A1 |
Number | Date | Country |
---|---|---|
829122 | Jul 1956 | GB |
2090942 | Jul 1982 | GB |
62146234 | Jun 1987 | JP |
Number | Date | Country | |
---|---|---|---|
20060048556 A1 | Mar 2006 | US |
Number | Date | Country | |
---|---|---|---|
60608021 | Sep 2004 | US |