| 摘要 |
There is provided a rocker arm of a kind in which even though the rocker arm is manufactured by the use of a press working technique the arm width can be minimized while the flat outer surface region of a required width is secured on an outer surface of the connecting wall, thereby contributing to reduction in size and weight of the rocker arm. This rocker arm 1 is capable of being driven by a cam 2 for selectively opening and closing a valve 3 of an internal combustion engine. This rocker arm 1 includes an arm body 4 prepared by bending a single plate material to represent a generally inverted U-shaped section including opposite side walls 5 and a connecting wall 6 bridging between the opposite side walls 5 . A roller 10 engageable with the cam 2 is rotatably mounted on a portion of the arm body 4 generally intermediate of the length thereof. A valve drive element 8 is mounted on one end of the arm body 4 for driving the valve 4 , while an end portion of the connecting wall 6 adjacent the other end of the arm body 4 is formed with an internally helically threaded hole 12 for threadingly receiving therein an externally helically threaded pivot member 7 . An outer chamfered corner delimited between an outer surface of the connecting wall 6 and an outer surface of each of the opposite side walls and formed by bending is deformed to represent a plastically deformed portion 4 a so formed by means of a plastic deformation technique that the outer chamfered corner represents a small radius of curvature R.
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