Oil distribution system for an internal combustion engine valvetrain

Description

CROSS REFERENCES AND PRIORITIES

This application claims priority from U.S. Provisional Application No. 63/669,847 filed on Jul. 11, 2024, the teachings of which are incorporated by reference herein in their entirety.

BACKGROUND

Internal combustion engines are used as the primary power plant for most modern vehicles. The internal combustion engine utilizes expansion of gases within a cylinder head wherein pistons, connecting rods, and a crank shaft convert a controlled explosion in a cylinder chamber into rotational movement. Control of the cylinder chamber is performed by sequential operation of intake and exhaust valves operated by a camshaft, cam follower (sometimes referred to as a lifter), push rod, and rocker arm for conducting air flow into and out of the cylinder chambers.

Two basic configurations of rocker arms are utilized. The first—commonly referred to as stud mounted rocker arms—include a threaded stud installed within the cylinder head. The rocker arm is connected to the threaded stud by passing the threaded stud through a hole in the rocker arm and securing the rocker arm to the stud with an adjustable fastener which allows for users to adjust the valve lash of the individual valve.

The second—commonly referred to as shaft mounted rocker arms—include a series of threaded holes in the cylinder head. A shaft about which the rocker arm pivots is bolted directly to the cylinder head—or in some instances bolted to a plate which is connected to the cylinder head.

Shaft mounted rocker arm systems commonly encounter issues with providing sufficient oil to lubricate the valve spring, valve, rocker arm and/or associated valvetrain components during operation. Several solutions have been proposed for providing sufficient oil to lubricate valvetrain components—including valve springs, valves, and rocker arms in a shaft mounted rocker arm system. One such solution is disclosed in U.S. Pat. No. 5,125,373 A which teaches an oil passage structure for a rocker-arm shaft for an internal combustion engine, comprises an outer cylindrical member for rotatably supporting rocker arms and an inner cylindrical member press-fitted into the outer cylindrical member. The inner cylindrical member employs at least one concavity having a given axial length for defining at least two axial oil passages.

In practice, the existing solutions often utilize a series of holes drilled into a base member to which the shaft mounted rocker arms are connected. Oil from below the rocker arm assembly passes into these holes and is discharged from the top of the base member to provide lubrication to the valvetrain components—including valve springs, valves, and rocker arms. These drilled holes suffer from several defects. Notably, precision drilling is required to ensure accurate alignment of the holes with the valvetrain components. Further, the holes can be difficult to clean of debris during servicing of the engine.

The need exists, therefore, for an improved oil distribution system for an internal combustion engine valvetrain which provides more accurate alignment of oil discharge holes with valvetrain components—including valve springs, valves, and rocker arms—and which can easily be cleaned during servicing of the engine.

SUMMARY

Described herein is an oil distribution system for an internal combustion engine valvetrain. The oil distribution system includes a rocker arm base member and a base plate. The rocker arm base member has a base upper surface, a base lower surface, a plurality of sidewalls spanning a distance between the base upper surface and the base lower surface, and a plurality of base mounting holes extending from the base upper surface through the base lower surface. The rocker arm base member includes a distribution slot, a plurality of oil receiving holes, and a plurality of oil distribution holes. The distribution slot is disposed in the base lower surface. The plurality of oil receiving holes extend from at least one sidewall of the plurality of sidewalls and/or from the base upper surface into the distribution slot. The plurality of oil distribution holes pass from the distribution slot through the base upper surface. The base plate is configured to cover at least a portion of the base lower surface including at least a portion of the distribution slot. The distribution slot is configured to receive oil from the plurality of oil receiving holes and pass at least a first portion of the oil to the plurality of oil distribution holes. The oil distribution holes are configured to discharge at least a second portion of the oil past the base upper surface.

In some embodiments, the rocker arm base member may include a first rocker arm mounting structure. When present, the first rocker arm mounting structure may extend from the base upper surface. At least a first oil distribution hole of the plurality of oil distribution holes may be aligned with the first rocker arm mounting structure.

In certain embodiments, the rocker arm base member may include a second rocker arm mounting structure. When present, the second rocker arm mounting structure may extend from the base upper surface. At least a second oil distribution hole of the plurality of oil distribution holes may be aligned with the second rocker arm mounting structure.

In some embodiments, the base plate may include a plate upper surface and a plate lower surface. A plurality of plate mounting holes may extend from the plate upper surface through the plate lower surface. Preferably, at least one plate mounting hole of the plurality of plate mounting holes may be aligned with at least one base mounting hole of the plurality of base mounting holes when the base plate is covering at least a portion of the base lower surface. More preferably, each plate mounting hole of the plurality of plate mounting holes will be aligned with at base mounting hole of the plurality of base mounting holes when the base plate is covering at least a portion of the base lower surface.

BRIEF DESCRIPTION OF FIGURES

FIG. 1 illustrates a lower perspective view of an oil distribution system for an internal combustion engine valvetrain.

FIG. 2 illustrates an exploded lower perspective view of an oil distribution system for an internal combustion engine valvetrain.

FIG. 3 illustrates a cross section view of a rocker arm base member for an oil distribution system for an internal combustion engine valvetrain.

FIG. 4 illustrates an upper perspective view of an oil distribution system for an internal combustion engine valvetrain.

FIG. 5 illustrates an upper perspective view of an oil distribution system for an internal combustion engine valvetrain with an installed pair of rocker arms.

FIG. 6 illustrates an exploded upper perspective view of an oil distribution system for an internal combustion engine valvetrain with a pair of rocker arms.

DETAILED DESCRIPTION

Described herein is an oil distribution system for an internal combustion engine valvetrain. Reference is made to the Figures in which, unless otherwise noted, like numbers refer to like structures. As described herein and in the claims, the following numbers refer to the following structures as noted in the Figures.

• • 10 refers to an oil distribution system.
  • 20 refers to an oil flow path.
  • 100 refers to a rocker arm base member.
  • 101 refers to a base first end.
  • 102 refers to a base upper surface.
  • 103 refers to a base second end.
  • 104 refers to a base lower surface.
  • 105 refers to a base first edge.
  • 106 refers to a sidewall.
  • 107 refers to a base second edge.
  • 108 refers to a base mounting hole.
  • 110 refers to a distribution slot.
  • 120 refers to an oil receiving hole.
  • 130 refers to an oil distribution hole.
  • 131 refers to a first oil distribution hole.
  • 132 refers to a second oil distribution hole.
  • 150 refers to a first rocker arm mounting structure.
  • 160 refers to a second rocker arm mounting structure.
  • 200 refers to a base plate.
  • 210 refers to a plate upper surface.
  • 220 refers to a plate lower surface.
  • 230 refers to a plate mounting hole.
  • 300 refers to a first rocker arm.
  • 400 refers to a second rocker arm.

FIG. 1 illustrates a lower perspective view of an exemplary embodiment of an oil distribution system (10) for an internal combustion engine valvetrain. As shown in FIG. 1, the oil distribution system includes a rocker arm base member (100) and a base plate (200).

FIG. 2 illustrates an exploded lower perspective view of an exemplary embodiment of an oil distribution system (10) for an internal combustion engine valvetrain showing additional features of the rocker arm base member (100) and the base plate (200). As shown in FIG. 2, the rocker arm base member includes a base upper surface (102), a base lower surface (104) and a plurality of sidewalls (106) spanning a distance between the base upper surface and the base lower surface. A plurality of base mounting holes (108) extend from the base upper surface through the base lower surface and are configured to receive a fastener—such as a bolt or a stud with a nut—to attach the rocker arm base member to a cylinder head (not shown) of an internal combustion engine.

The rocker arm base member (100) includes a distribution slot (110) disposed in the base lower surface (104). In some embodiments, the distribution slot will originate at a base first end (101) and extend through a base second end (103). In other embodiments, the distribution slot will originate at the base first end without extending through the base second end. In yet other embodiments, the distribution slot will originate interior from the base first end and extend through the base second end. In still other embodiments, such as that shown in FIG. 2, the distribution slot will originate interior from the base first end without extending through the base second end.

A plurality of oil receiving holes (120) extend from at least one sidewall of the plurality of sidewalls (106) of the rocker arm base member (100). Each oil receiving hole of the plurality of oil receiving holes extends into and along the distribution slot (110) to allow oil exterior to the rocker arm base member to pass into the distribution slot. While the oil receiving holes may be located at any one sidewall of the plurality of sidewalls—including a sidewall corresponding to the base first end (101), the base second end (103), the base first edge (105), and/or the base second edge (107)—it is preferred that at least one of the oil receiving holes is located in a sidewall corresponding to the base first edge as shown in FIG. 2.

A plurality of oil distribution holes (130) pass from the distribution slot (110) through the base upper surface (102) to allow at least a portion of the oil that passed into the distribution slot via the oil receiving holes to be discharged past the base upper surface and onto at least one rocker arm that is connected to the rocker arm base member (100). While the oil distribution holes may be located in any number of locations, it is preferred that each rocker arm connected to the rocker arm base member have at least one oil distribution hole substantially aligned to discharge oil onto valvetrain components such as a valve spring, valve, and/or rocker arm.

FIG. 2 also illustrates additional features of the base plate (200). As shown in FIG. 2, the base plate includes a plate upper surface (210) and a plate lower surface (220) opposite the plate upper surface. When the base plate is attached to the rocker arm base member (100) as shown in FIG. 1, the plate upper surface abuts against at least a portion of the base lower surface (104) such that the base plate covers at least a portion of the base lower surface. Preferably, the portion of the base lower surface covered by the base plate will include all—or at least a portion—of the distribution slot (110).

The base plate (200) also includes a plurality of plate mounting holes (230) with each mounting hole extending from the plate upper surface (210) through the plate lower surface (220). Preferably, at least one plate mounting hole of the plurality of plate mounting holes will be aligned with at least one base mounting hole (108) of the plurality of base mounting holes when the lower plate is covering at least a portion of the base lower surface such that a single fastener—such as a bolt or a stud with a nut—may pass through both the base mounting hole and the plate mounting hole to attach the rocker arm base member (100) to the base plate and to connect the assembled rocker arm base member and base plate to the cylinder head (not shown). In more preferred embodiments, each plate mounting hole of the plurality of plate mounting holes will be aligned with a separate base mounting hole of the plurality of base mounting holes.

FIG. 3 illustrates a longitudinal cross section of the rocker arm base member (100) with arrows illustrating the oil flow path (20). As shown in FIG. 3, oil from exterior to the rocker arm base member (100)—typically within the cylinder head below the base lower surface ((104) as shown in FIG. 2)—enters the rocker arm base member through the plurality of oil receiving holes (120). Pressure within the cylinder head beneath the engine's valve cover along with turbulence caused by movement of rocker arms, valves, valve springs, and pushrods forces the oil into the plurality of oil receiving holes. The pressure and turbulence, combined with the volume of oil, then causes the oil to pass into the distribution slot (110). The pressure and turbulence, combined with the volume of oil, then causes the oil to flow along the distribution slot until it arrives at an oil distribution hole (130) of the plurality of oil distribution holes. Once the oil arrives at an oil distribution hole, the pressure and turbulence along with the volume of oil forces a portion of the oil through the oil distribution hole such that the portion of oil sprays upwardly onto at least a portion of a rocker arm (300/400 as shown in FIGS. 5 and 6), a valve spring, a valve, and/or related valvetrain components to provide lubrication to the valvetrain components during operation. The base plate ((200) as shown in FIGS. 1 and 2) covers the distribution slot and prevents any portion of the oil from escaping the distribution slot without being discharged through the oil distribution hole(s).

FIG. 4 illustrates a top perspective view of the rocker arm base member (100). As shown in FIG. 4, the rocker arm base member includes at least a first rocker arm mounting structure (150) extending from the base upper surface (102). Many different forms of first rocker arm mounting structure may exist depending on the structure of the first rocker arm ((300) as shown in FIG. 5) and the mechanism for attaching said first rocker arm to the rocker arm base member. In the exemplary embodiment shown in FIG. 4, the first rocker arm mounting structure takes the form of a first tower extending upwardly from the base upper surface and including a first tower recess. A first rocker mounting hole extends into—but not necessarily through—the first tower recess. The first rocker mounting hole being configured to receive a first fastener to connect a portion of the first rocker arm to the rocker arm base member as shown in FIG. 5—which is an assembled view showing the first rocker arm attached to the rocker arm base member—and FIG. 6—which is a partially exploded view thereof. Further, at least a first oil distribution hole (131) of the plurality of oil distribution holes may be aligned with the first rocker arm mounting structure as illustrated in FIG. 4.

FIG. 4 also illustrates the rocker arm base member (100) including at least a second rocker arm mounting structure (160) extending from the base upper surface (102). Many different forms of second rocker arm mounting structure may exist depending on the structure of the second rocker arm ((400) as shown in FIG. 5) and the mechanism for attaching said second rocker arm to the rocker arm base member. In the exemplary embodiment shown in FIG. 5, the second rocker arm mounting structure takes the form of a second tower extending upwardly from the base upper surface and including a second tower recess. A second rocker mounting hole extends into—but not necessarily through—the second tower recess. The second rocker mounting hole being configured to receive a second fastener to connect a portion of the second rocker arm to the rocker arm base member as shown in FIG. 5—which is an assembled view showing the second rocker arm attached to the rocker arm base member—and FIG. 6—which is a partially exploded view thereof. Further, at least a second oil distribution hole (132) of the plurality of oil distribution holes may be aligned with the second rocker arm mounting structure as illustrated in FIG. 4.

In the exemplary embodiment shown in FIG. 4 through FIG. 6, each of the first rocker arm mounting structure (150) and the second rocker arm mounting structure (160) includes a portion of a third tower extending upwardly from the base upper surface (102) and including a plurality of saddle mounting holes disposed therein. The plurality of saddle mounting holes being configured to receive a third fastener to connect a saddle to the third tower and hold each of the first rocker arm (300) and the second rocker arm (400) in place. The third tower includes a pair of concave recesses—one of which is oriented to receive a convex surface of a portion of a first shaft for the first rocker arm while the other is oriented to receive a convex surface of a second shaft of the second rocker arm. Correspondingly, a bottom side of the saddle includes a pair of concave surfaces configured to fit over and around the convex surfaces of the portion of the first shaft and the second shaft which are disposed into the concave recesses of the third tower.

In the embodiments shown in FIGS. 5 and 6, the first rocker arm (300) and the second rocker arm (400) may be thought of as a pair of rocker arms. One of said rocker arms being configured to actuate an intake valve of one cylinder of the internal combustion engine while the other rocker arm is configured to actuate an exhaust valve of the same cylinder of the internal combustion engine. While FIGS. 5 and 6 illustrate rocker arms for a single cylinder of an internal combustion engine, one of ordinary skill will recognize that the configuration may apply to engines having multiple cylinders such as is shown in FIGS. 1 through 4—in which case each cylinder may have its own pair of rocker arms configured to actuate that cylinder's individual intake and exhaust valves.

The oil distribution systems disclosed herein represent an improvement over the prior art. The distribution slot in the base lower surface can be easily and precisely machined to accurately align with the valve spring, valve, rocker arm, and/or associated valvetrain components without the need for difficult precision drilling. Subsequent covering of the distribution slots by the base plate allows a user to easily access the distribution slot, oil receiving holes, and oil distribution holes for cleaning of debris during servicing of the engine.

While the oil distribution system has been described as having one or more exemplary designs, the present article may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the oil distribution system using their general principles.