| 摘要 |
A rocker arm has a one-piece metal body made by cold-forming operations, including staming, extruding, coining, and back-packing. The rocker arm includes an intermediate portion and two end portions. The intermediate portion has substantially parallel side walls with a large, generally rectangular opening at the top and with two end top walls extending sharply downwardly therefrom. The parallel side walls are deep and both the side walls and top walls are thinner at upper portions than at lower portions. A first end portion of the body has a wide top wall with arcuate side walls. A method of making the rocker arm includes forming a metal blank with a U-shaped cross section having a convex central portion. A slot is formed in the central portion and that portion is then pushed out or extruded to form the large, generally rectangular opening.
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