MULTIPLE PART TUBULAR MEMBER AND METHOD AND APPARATUS FOR MANUFACTURE THEREOF

摘要

The crankshaft bearing cap of a connecting rod is formed from a forged rod blank which includes an integral circular head having an internal bearing surface and have integrally formed interconnecting lug portions. The lug portions are provided with cracking openings aligned with and parallel to a cracking plane. Each of the openings is provided with a cracking notch or recess which extends downwardly from one side of the head between twenty and fifty percent of the opening length. The assembly is located on a lubricated supporting bed with the unnotched face resting on the supporting surface. Interconnected cracking pins with a suitable tapered configuration are simultaneously forced into the cracking holes with an impact type force. The tapered pins are interconnected to a common support equalizing the cracking impact pressure as the pins are moved into cracking openings. Each of the notches is formed with a V-shape with an inclusive angle of forty-five degrees and a relatively shallow depth of from 0.010 to 0.020 inches to define a sharp apex in the cracking plane. Suitably sized and circumferentially spaced radial lubrication holes in the cap provide an improved lubrication and simplify the manufacturing process. The lubrication holes are spaced in accordance with the spacing of the needle roller bearings such that only one roller bearing is in aligned overlying relationship with each lubrication hole at any given instant.