Patent Application
20070044745
This invention relates to a rocker arm with a structurally-integral, upwardly-facing socket at an intermediate portion thereof for engaging a pivot ball about which the rocker arm pivots and having a lubricating access formed through and from the top of the narrow width of rocker arm, the lubricating access directly providing a flow path to the push rod contacting area of the rocker arm.
A rocker arm of the kind which pivots about pivot balls and have means at one end for engaging and operating a valve of an internal combustion and when pivoted by a push rod at the other end of the rocker arm, and are of the particular kind with which the invention is concerned, as disclosed in U.S. Pat. No. 5,038,726, the disclosure of which is incorporated herein by reference.
The rocker arm in accordance with the invention has a cold-formed, one-piece metal body with a large intermediate opening therein. The opening is of trapezoidal configuration with a lower edge which is longer than an upper edge. The one-piece body has a structurally-integral, outwardly-flared portion at an intermediate portion of the lower edge of the opening, which flared portion defines an upwardly-facing socket for engaging a pivot ball. The structurally-integral socket is formed on the rocker arm body by cold-forming, specifically by stamping operations.
Experience has demonstrated that, particularly, under internal combustion engine severe operating conditions, the desired quantity of lubricating function at the push rod end of the rocker arm is lacking.
It is accordingly an object of the invention to provide an improved rocker arm in which lubricating performance at the push rod end is substantially enhanced, providing a desirable abundance of lubrication to the entire rocker arm system.
It is another object of the invention to provide a lubricating system which, of itself, supplies ample lubrication and thereby eliminates the need for a secondary oil supply means, such as an oil rail.
Various other objects and advantages of the invention will be apparent from the following detailed description of a preferred embodiment thereof, reference being made to the accompanying drawings.
Referring to
One end of the rocker arm 12 engages the upper end of a push rod 26 and the other end engages the upper end of a valve stem 28. The valve stem extends upwardly from a valve (not shown) in the cylinder head 20 and through a coiled compression spring 30 located between the cylinder head 20 and a retaining ring 32 which is mounted on the valve stem.
As seen by reference to
The rocker arm 34 has a large central opening 48 therein in a generally trapezoidal shape. It includes a rounded upper edge 50, straight side edges 52 and 54 which converge in an upward direction, and rounded bottom edge portions 56 and 58. The rounded upper edge 50 is substantially parallel to the upper rounded edge of the rocker arm body 34 located above the opening 48. A structurally-integral, upwardly-facing pivot ball socket 60 is formed in the rocker arm body 34 between the lower edge portions 56 and 58 and has a generally semispherical recess 62 with a further central recessed area 64 of generally semispherical shape. The recessed area 64, of shorter radius than the recess 62, helps to assure that the pivot ball 24 will fit fully with the recess 62 and can provide a pocket for lubricant. The socket 60 is formed directly from the metal body 34 between the lower edge portions 56 and 58 of the opening 48. As such, no assembly operation is required to assemble the socket with the body and the socket cannot be incorrectly assembled or not assembled at all, as could otherwise occur. Further, there is no possibility that the socket will come loose during operation.
It will be apparent that while a lubricating access part is shown formed solely accessing the semispherical socket 42 that a similarly lubrication access opening 45 may also be provided in the semispherical socket 38.
Various modifications of the above-described embodiment of the invention will be apparent to those skilled in the art, and it is to be understood that such modifications can be made without departing from the scope of the invention, if they are within the spirit and the tenor of the accompanying claims.
