In the past, several methods have been employed to form banjo type axle housings. A first known method involved forming the hollow cylindrical central member and the two beam portions as three separate pieces. The beam portions were then secured to the central member by welding or other means to form the housing. A second known method involved forming the entire housing from a single tubular blank. A hole was cut through the center of the blank, then formed into the hollow cylindrical central member, while the opposed end portions of the blank extended outwardly therefrom to form the beams. A third known method involved forming the central member integrally from the ends of the two beams. This was accomplished by splitting one end of each of the two beam portions, spreading the two split ends apart, and securing the two spread ends together to form the hollow cylindrical central member.
A fourth and one of the most common methods for manufacturing the banjo type axle housings involves forming two opposite halves of the axle housing by stamping or forging from a pre-cut blank of sheet steel. Next, the two axle housing halves are then welded along mated horizontal edges, and then the axle assembly is completed in a known manner. The described method is well known in the art and disclosed in a number of U.S. Patents, e.g. U.S. Pat. Nos. 4,921,159 and 2,674,783, incorporated herein by reference.
The above fourth method for manufacturing the banjo type axle housings is relatively simple and efficient. However, tooling used for stamping the axle housing halves is very expensive. Moreover, when a number of axle housings of various sizes are produced, a corresponding number of different metal forming apparatuses has to be employed that requires rather large tooling expenses.
While the above-described known methods have been used successfully to form banjo type axle housings, it has been found that all require large tooling expenses, especially when a number of different axle housing designs is produced by the same manufacturer.
Therefore, it would be desirable to provide an improved method for forming a banjo type axle housing which employs a common metal forming apparatus and a single size of the metal stamping for producing different axle housing designs, thus considerably reducing cost of manufacture.
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