Pivot Ball Rocker Arm Lubricating Access

Abstract

A lubricating, enhancing access is provided for a rocker arm for an internal combustion engine. The rocker arm has a cold-formed, one-piece metal body with a narrow width and a substantial depth. The body has a semispherical socket at both ends for engaging respectively the end of a valve stem and the upper end of a push rod. An intermediate portion of the body has a large generally trapezoidal opening with a lower edge longer than an upper edge and a middle portion having a structurally-integral, outwardly-flared portion defining an upwardly-facing socket for engaging a pivot ball wherein the rocker arm pivots during operation. The lubricating passage is formed transversely through and from the top of the narrow width of the rocker arm in at the push rod end of the rocker arm to access and open into the socket recess.

Description

DESCRIPTION

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.

BACKGROUND OF THE INVENTION

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.

SUMMARY OF THE INVENTION

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.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view in elevation of a rocker arm assembly in accordance with the invention and a portion of an internal combustion engine upon which it is mounted.

FIG. 2 is a side view in elevation of the rocker arm of the invention illustrating the push rod end lubricating access.

FIG. 3 is a top view in elevation of the rocker arm of the invention illustrating the push rod end lubricating access.

FIG. 4 is a bottom view in elevation of the rocker arm of the invention illustrating the push rod end lubricating access.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1 of the drawing, a rocker arm assembly in accordance with the invention is indicated at 10 and includes a cold-formed, one-piece metal rocker arm 12 which is pivotally supported by a supporting pedestal or post 14. Two machine bolts or other suitable threaded fasteners 16 extend through enlarged end portions 18 of the post and mount it on a cylinder head 20 of an engine block. The post also has an enlarged bearing support 22 which receives a pivot ball 24.

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 FIG. 2 of the drawing, the rocker arm 12 includes a one-piece metal body 34 which is made from a single, thick metal plate. One end portion 36 of the rocker arm differs from that of U.S. Pat. No. 5,038,726 in that the end is modified and formed so as to have a ball socket formed similar to the opposite end of the rocker arm, i.e., each end has a generally semispherical downward facing recess, one end 38 which fits over an intermediate part (not shown) with a conforming rounded end and engages the top of valve stem 28 and the other end portion 40 of the rocker arm body with downwardly facing recess 42 fits over the upper end of the push rod 26 and receives oil through the vertically formed passage 44. It has been discovered according to the invention that by providing an oil distributing passage 44, formed longitudinally, as distinguished from the transverse opening shown in the rocker arm of U.S. Pat. No. 5,038,726, oil supply to the system is surprisingly enhanced. As a consequence the full lubricating function is served. At lower engine RPM the oil adheres to and flows along the rocker arm surfaces to lubricate the pivot and valve end. At higher engine RPM the oil produces a “splash” lubrication which serves to provide an abundance of lubricating oil to the entire mechanism. The lubrication is of such enhanced quantity as to provide sufficient lubricant even under the most extreme engine operating conditions.

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.

Claims

1. A rocker arm for an internal combustion engine and adapted for operation by a push rod to operate a valve, said rocker arm comprising a cold-formed, one-piece metal body having a narrow width and a substantial depth, said body having a semispherical push rod socket at one end of said rocker arm for engaging a push rod, a longitudinal lubricating opening formed through the depth of said rocker arm accessing and opening into the push rod socket, said rocker arm having a semispherical socket at the other end for engaging a valve stem of the valve, an intermediate portion of said body having a large opening defined, in part, by side edges and a lower edge, and an intermediate portion of said lower edge having structurally integral, outwardly flared portions defining an upwardly facing socket for engaging a pivot ball.

2. The rocker arm of claim 1 wherein the lubricating opening is counter bored at the top of the push rod end of the rocker arm.

3. The rocker arm of claim 1 wherein the lubricating opening is counter bored at the socket access at the push rod end of the rocker arm.

4. In a rocker arm for an internal combustion engine and adapted for operation by a push rod to operate a valve and comprising a cold-formed, one-piece metal body having a narrow width and a substantial depth, a semispherical socket means at one end for engaging a push rod and a semispherical socket at the other end for engaging the end of a valve stem, an intermediate portion of said body having a large opening defined, in part, by side edges and a lower edge, and an intermediate portion of said lower edge having structurally integral, outwardly flared portions defining an upwardly facing socket for engaging a pivot ball, the improvement comprising providing a lubricating passage formed through the depth of the rocker arm accessing and opening into the push rod socket.

5. The rocker arm of claim 4 additionally provided with a lubricating passage through the depth of the rocker arm at the valve stem end and accessing and opening into the valve stem socket.