throbber
(12> Ulllted States Patent
`Pryba et al.
`
`US006230676B1
`(16) Patent N63
`US 6,230,676 B1
`(45) Date of Patent:
`May 15, 2001
`
`(54) INTERCHANGEABLE ROCKER ARM
`ASSEMBLY
`
`(75) Inventors: Stanley J. Pryba, Toledo; Rodney E.
`DeLong; Terry I‘I Shook,
`of
`Sylvania, all of OH (US)
`
`(73) Assignee: Toledo Technologies Inc., Perrysburg,
`OH (US)
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`.
`_
`patent is extended or adJusted under 35
`U.S.C. 154(b) by 0 days.
`
`(21) APPL NO; 09/298,382
`
`(22) Filed:
`
`Apr. 23, 1999
`
`(51) Int. Cl.7 ...................................................... .. F01L 1/18
`(52) US. Cl. ................................... .. 123/9039; 123/9036;
`74 /559
`(58) Field Of Search ............................ .. 123/9036, 90.39,
`123/9041 9044. 74 519 559
`’
`’
`’
`References Cited
`
`(56)
`
`U-S~ PATENT DOCUMENTS
`
`7/1996 Uchida et a1. .
`5,535,641
`5,553,583 * 9/1996 Jones ............................... .. 123/9036
`5,596,958
`1/1997 Miller.
`576787305
`10/1997 Nagano 6F ‘11- -
`MOtOl'laShl et a1. .
`3/1998 Calka 6181..
`5,730,093
`7/1998 Kotani.
`5,774,984
`FOREIGN PATENT DOCUMENTS
`
`1538897
`
`1/1979 (GB) .
`
`* cited by examiner
`
`Primary Examiner—Thomas Denion
`Assistant Examiner—Tu M. Nguyen
`(74) Attorney, Agent, or Firm—Rader, Fishman & Grauer
`PLLC
`(57)
`
`ABSTRACT
`
`A rocker arm assembly for an internal Combustion engine
`includes a central mounting shaft and a rocker arm rotatably
`mounted to the Central Shaft wherein the rocker arm has a
`generally planar main body With a valve contacting end and
`a push rod contacting end. A convex surface is formed on a
`loWer edge of a valve contacting surface and the push rod
`contacting end includes a generally semi-spherical recess
`that creates generally semi-spherical outer projections on the
`sides of the rocker arm main body. The central mounting
`shaft according to one embodiment of the present invention
`_
`_
`1s a generally holloW, tubular shaft having spaced apart
`lubrication apertures for providing lubricant to each rocker
`arm. A second embodiment of the present invention has a
`central mounting shaft that includes a plurality of relatively
`short, hardened shafts connected together at respective
`adjoining ends by a spacer sleeve to provide a rocker arm
`assembly having greater stiffness.
`
`10 Claims, 6 Drawing Sheets
`
`*
`
`*
`
`1,346,116
`
`1,617,986
`
`7/1920 Waters ............................ .. 123/90.36
`2/1927 Blank _ _ _ _ _
`_ _ _ __ 123/9036
`9/1936 Russell
`123/9036
`2,053,743
`3,146,767 * 9/1964 Dadd _ _ _ _ _ _
`_ _ _ __ 123/9036
`3,410,366 * 11/1968 Winter, Jr. ..
`. 123/9036
`4,245,523 * 1/1981 Wherry - - - - - -
`- - - - -- 74/519
`4,630,576 * 12/1986 Raymond
`- 123/9036
`476557177 * 4/1987 Wells et a1‘
`123/9036
`4,718,379 * 1/1988 Clark ............................... .. 123/9039
`5,273,006
`12/1993 Schiiperténs et a1. .
`5,325,825
`7/1994 Schmidt et a1. .
`5,372,097
`12/1994 Joseph et al. .
`
`CATERPILLAR EXHIBIT 1009
`
`Page 1 of 12
`
`

`

`U.S. Patent
`US. Patent
`
`May 15,2001
`May 15, 2001
`
`Sheet 1 6f 6
`Sheet 1 0f 6
`
`US 6,230,676 B1
`US 6,230,676 B1
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`Page 2 of 12
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`Page 2 of 12
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`

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`U.S. Patent
`US. Patent
`
`May 15,2001
`May 15, 2001
`
`Sheet 2 6f 6
`Sheet 2 0f 6
`
`US 6,230,676 B1
`US 6,230,676 B1
`
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`Page 3 of 12
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`Page 3 of 12
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`

`U.S. Patent
`US. Patent
`
`May 15,2001
`May 15, 2001
`
`Sheet 3 6f 6
`Sheet 3 0f 6
`
`US 6,230,676 B1
`US 6,230,676 B1
`
`
`
`32
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`11
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`Page 4 of 12
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`Page 4 of 12
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`U.S. Patent
`US. Patent
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`May 15,2001
`
`Sheet 4 6f 6
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`US 6,230,676 B1
`US 6,230,676 B1
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`U.S. Patent
`
`May 15,2001
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`Sheet 5 6f 6
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`US 6,230,676 B1
`
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`Page 6 of 12
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`

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`U.S. Patent
`
`May 15,2001
`
`Sheet 6 6f 6
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`US 6,230,676 B1
`
`140
`
`Fig. 12
`
`144
`
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`
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`
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`
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`Page 7 of 12
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`

`

`US 6,230,676 B1
`
`1
`INTERCHANGEABLE ROCKER ARM
`ASSEMBLY
`
`FIELD OF THE INVENTION
`The present invention relates to rocker arm assemblies for
`internal combustion engines and, in particular, to internal
`combustion engines for motor vehicles. The rocker arm
`assemblies of the present invention have unique lubrication
`systems and also permit both a bearingless and a roller
`bearing type rocker arm shaft assembly to be interchange
`ably mounted in a same engine.
`
`BACKGROUND OF THE INVENTION
`Rocker arm assemblies are utilized in internal combustion
`engines for alternately actuating intake and exhaust valves.
`As an engine cam shaft rotates, a push rod is selectively
`actuated by cams located on the cam shaft. The push rods,
`in turn, direct an upWard force on one end of a rocker arm
`to cause the rocker arm to pivot about a mounting shaft. As
`the rocker arm pivots, its opposite end generates a doWn
`Ward force to selectively open an intake or exhaust engine
`valve.
`Typically, rocker arms are integral, one-piece parts having
`a generally U-shaped cross-section including a pair of
`opposing side Walls separated by a bottom Wall and a pair of
`end Walls disposed betWeen the side Walls. Rocker arms are
`conventionally either stamped or cast. The above described
`U-shaped rocker arms are commonly referred to as “boat
`type” rocker arms. U-shaped rocker arms generally have
`adequate stiffness. HoWever, the increased mass and Width
`of U-shaped rocker arms negatively affects the moment of
`inertia, Which is important for engine components recipro
`cating at very high frequencies. Increased mass also
`decreases vehicle fuel ef?ciency. Some other disadvantages
`of U-shaped rocker arms include loud operating noise,
`vibration, and undesirable levels of friction.
`Lubrication in conventional U-shaped rocker arm assem
`blies is provided through holloW push rods that channel
`lubricant up to a lubricant aperture in one end of an adjacent
`rocker arm. Then lubricant ?oWs onto the bottom Wall in
`betWeen the side Walls of the rocker arm.
`The previously knoWn rocker arm assemblies include
`variations having so-called “frictionless” bearings and
`assemblies Without bearings. HoWever, none of the prior
`knoWn devices alloW a bearingless rocker arm shaft assem
`bly to be interchanged With a frictionless bearing rocker arm
`shaft assembly Within the same basic engine design con
`?guration. The incompatibility of the prior art decreases
`engine manufacturer ?exibility by forcing a selection
`betWeen the higher costs associated With multiple engine
`design con?gurations or only being able to offer a single
`engine design With only one type of rocker arm s haft
`assembly.
`Further, the prior art rocker arm designs lack the ability to
`have a rocker arm supplier provide a fully pre-assembled
`rocker arm shaft assembly that can be shipped to and
`installed at the engine manufacturer’s assembly plant.
`Instead, the prior art designs require the engine manufacturer
`to pre-assemble the components. Thus, the prior art designs
`are more susceptible to having loose, individual component
`parts lost during shipping and handling. Moreover, the prior
`art designs increase inventory burden on the engine manu
`facturer and often result in inadequate rotation of parts in
`inventory.
`
`15
`
`25
`
`35
`
`45
`
`55
`
`SUMMARY OF THE INVENTION
`The present invention is directed to a rocker arm assembly
`including a central mounting shaft having at least one rocker
`
`65
`
`2
`arm rotatably mounted to the central shaft. The rocker arm
`has a generally planar main body With ?rst and second ends
`and ?rst and second side surfaces and a central aperture that
`receives a tubular section. In addition, the ?rst end of the
`rocker includes a convex surface for contacting a valve stem.
`The convex surface extends laterally beyond at least one of
`the ?rst and second side surfaces of the planar main body.
`The second end of the rocker arm includes a generally
`holloW recess formed adjacent an edge of the planar main
`body such that an outer projection is formed on each of the
`?rst and second side surfaces of the planar main body. The
`holloW recess receives an end of a push rod for transmission
`of forces from an engine cam shaft. Also, the tubular section
`of the rocker arm surrounds the central shaft and intersects
`the main body at a predetermined angle.
`The present invention further provides an improved lubri
`cation system for ef?ciently distributing lubricant to the
`valve stem contact surface of the rocker arm. In one embodi
`ment of the present invention, a holloW central shaft has
`lubricant apertures that align With a lubricant bore provided
`in the rocker arm. The lubricant bore of the rocker arm
`extends from the central aperture of the rocker arm to a top
`edge of the rocker arm, near a high point or apex thereof
`Thus, lubricant is channeled up from the holloW central shaft
`through the rocker arm to an apex on its top edge before
`?oWing doWnWardly toWard the valve stem contact surface
`via a groove located on the outer edge of the rocker arm.
`Such a lubrication system permits fast delivery of lubricant
`because the lubricant ?oWs over a shorter distance from an
`approximate center of the rocker arm to the valve stem
`contact surface.
`According to a second embodiment of the present
`invention, another improved lubrication system is provided.
`In the second embodiment, a central mounting shaft is
`formed from a series of relatively short, hardened shafts
`connected together at respective adjoining ends by a joining
`spacer sleeve. The joining spacer sleeve includes a split for
`increasing clamping load to retain the adjoining ends of the
`shafts. Further, a lubrication ?oW channel is provided on the
`joining spacer sleeve to collect and direct lubricant toWard
`an interface betWeen the rocker arm and the central mount
`ing shaft. In the second embodiment, lubricant ?oWs through
`a holloW push rod, up through a lubricant aperture in one end
`of the rocker arm, and then to the valve stem contact end of
`the rocker arm via a groove in the rocker arm top surface.
`Lubricant also over?oWs from the groove and is caught in
`the channel of the joining spacer sleeve to direct lubricant
`toWard roller bearing elements on Which the rocker arms are
`mounted.
`In addition, a thrust Washer is optionally located on the
`central mounting shaft and has a central aperture for receiv
`ing the central shaft. The thrust Washer has a recessed
`portion on an inside diameter to form a lubricant passage
`Way through the thrust Washer to lubricate a set of roller
`bearings that mount the rocker arm onto the central mount
`ing shaft.
`The rocker arm assemblies of the present invention have
`tWo piece rocker arms that are relatively thin, stamped plates
`connected to a tubular element. The different con?guration
`of the present rocker arms, (e.g., they are relatively thin
`compared to the prior art), alloWs a greater number of engine
`toWers to be provided on an engine, resulting in greater
`overall system stiffness. In addition, lighter Weight rocker
`arms have less reciprocating mass about the intake and
`exhaust valves, providing a loWer moment of inertia and
`increased engine efficiency. Thus, the present rocker arm
`
`Page 8 of 12
`
`

`

`US 6,230,676 B1
`
`3
`design reduces Weight and noise and has a better moment of
`inertia than traditional U-shaped rocker arms.
`In addition, a rocker arm subassembly is disclosed having
`a relatively short shaft With ?rst and second ends and a
`plurality of through bores for attaching the shaft to an
`engine. Only ?rst and second rocker arms are spaced apart
`on the short shaft and positioned for rotational movement. A
`spacer is located on the shaft betWeen the ?rst and second
`rocker arms to accurately position the ?rst and second rocker
`arms. At least tWo of the relatively short shafts are connected
`together to form an engine rocker arm assembly.
`Further, the present invention contemplates a complete
`assembly of rocker arms mounted on one or more shafts that
`can be shipped in a fully pre-assembled condition to an
`engine maker for ready installation into a cylinder head of an
`engine. The component parts of the rocker arm shaft assem
`bly are securely held together, preventing unWanted loss of
`parts during shipping and handling. Further, the present
`invention permits a main body of the shaft assembly to be
`positioned on toWers of an engine by alloWing integral
`fasteners to move a predetermined distance relative to the
`main body, but preventing the fasteners from completely
`separating from the main body. Such an approach is in direct
`contrast to the prior art Which has individual arms that are
`mounted to individual shafts at the engine maker’s site.
`
`10
`
`15
`
`25
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The features and inventive aspects of the present inven
`tion Will become more apparent upon reading the folloWing
`detailed description, claims, and draWings, of Which the
`folloWing is a brief description:
`FIG. 1 is a top vieW of a rocker arm assembly according
`to the present invention.
`FIG. 2 is a cross-sectional side vieW taken along lines
`2—2 of FIG. 1.
`FIG. 3 is an exploded perspective vieW of a portion of a
`rocker arm assembly according to the present invention.
`FIG. 4 is a cross-sectional vieW taken along lines 4—4 of
`FIG. 1.
`FIG. 5 is a cross-sectional vieW taken along lines 5—5 of
`FIG. 1.
`FIG. 6 is a side vieW of a fastener having a ferrule.
`FIG. 7 is a cross-sectional side vieW of a ferrule according
`to the present invention.
`FIG. 8 is a top vieW of a rocker arm assembly according
`to another embodiment of the present invention.
`FIG. 9 is a perspective vieW of a rocker arm according to
`the present invention.
`FIG. 10 is a cross-sectional vieW taken along line 10—10
`of FIG. 8.
`FIG. 11 is an exploded perspective vieW of a portion of a
`rocker arm assembly according to the second embodiment of
`the present invention.
`FIG. 12 is a cross-sectional vieW taken along line 12—12
`of FIG. 8.
`FIG. 13 is a cross-sectional vieW taken along line 13—13
`of FIG. 8.
`
`35
`
`45
`
`55
`
`DETAILED DESCRIPTION OF PREFERRED
`EMBODIMENTS
`
`FIGS. 1 and 3 shoW a rocker arm shaft assembly 20
`having a central mounting shaft 22 for rotatably supporting
`one or more rocker arms 24. A plurality of spacers 26 are
`
`65
`
`4
`attached to central mounting shaft 22 and correctly position
`rocker arms 24 along central shaft 22. In addition, one or
`more thrust Washers 28 are provided betWeen rocker arm 24
`and an adjacent spacer 26 to reduce Wear. Although thrust
`Washer 28 is shoWn only on one side of each rocker arm 24,
`the present invention contemplates having thrust Washers 28
`on both sides rocker arm 24 or none at all. Moreover, rocker
`arms 24 are bearingless and directly contact central shaft 22
`in a slip ?t condition that alloWs rocker arm 24 to be
`assembled onto central shaft 22 but minimiZes looseness in
`the connection during rocker arm rotation.
`As shoWn in FIG. 2, central mounting shaft 22 is prefer
`ably holloW and includes a plurality of lubricant passage
`Ways 30 extending from an inner periphery to an outer
`periphery thereof to insure adequate lubrication for rocker
`arm assembly 20. Further, central shaft 22 includes a plu
`rality of spaced apart through bores 32 positioned for
`corresponding alignment With a through bore 34 in spacer
`26. Afastener 36 extends through spacer 26 and central shaft
`22 for securely attaching rocker arm assembly 20 to a toWer
`38 of an engine block. ToWer 38 projects upWardly from a
`cylinder head (not shoWn) and includes a generally semi
`circular recess 39 that cradles and supports central shaft 22.
`Semi-circular recess 39 is dimensioned just slightly larger
`than central shaft 22 to permit assembly but prevent
`unWanted looseness or play.
`FIG. 3 shoWs an exploded perspective vieW of the present
`invention. Spacer 26 is generally saddle-shaped having a
`semi-circular pro?le that is approximately the same diameter
`as the outside diameter of central shaft 22 for containment
`of the central shaft 22. Spacer 26 is shaped and dimensioned
`to at least partially seal the upper surface of central shaft 22
`near bores 32 to permit central shaft 22 to be pressuriZed and
`prevent lubricant loss through bores 32. A central upWardly
`projecting boss 39, Which includes through bore 34, is
`provided on spacer 26 to create adequate surface engage
`ment area for fastener 36. In addition, each central longitu
`dinal end of spacer 26 includes an outWardly extending
`projecting tab 40 that is dimensioned to precisely space apart
`rocker arms 24 While limiting the amount of surface area
`contact for reduced frictional contact With thrust Washer 28
`or rocker arm 24.
`Optionally, but preferably, as shoWn in FIGS. 2 and 3, a
`ferrule or collar 41 is provided on fastener 36 and performs
`the tasks of retaining spacer 26 and fastener 36 on central
`shaft 22. Ferrule 41 has an outer diameter dimensioned to
`slip ?t in spacer bore 34 and press ?t into shaft through bore
`32, thereby retaining spacer 26 to shaft 22. An inner diam
`eter of ferrule 41 is dimensioned to alloW limited vertical
`movement of fastener 36 as shoWn in FIG. 5, but prevent
`complete removal of fastener 36. Thus, as main shaft 22 is
`positioned on toWer 38, fastener 36 is able to move vertically
`to a position that does not interfere With installation. Also,
`ferrule 41 prevents fastener 36 from backing out or being
`completely separated from the rocker arm shaft assembly 20.
`Thus, ferrule 41 extends into central shaft 22 in press ?t
`engagement With through bores 32 to attach spacer 26 to
`shaft 22 and retain fastener 36 With limited travel.
`FIGS. 6 and 7 illustrate further design details of ferrule
`41. FIG. 6 shoWs fastener 36 having a threaded portion 42
`at one end thereof. Ferrule 41 has an inner diameter smaller
`than or equal to the threaded portion 42 diameter, preventing
`total removal of fastener 36 from ferrule 41. Preferably,
`ferrule 41 is placed on fastener 36 prior to rolling of threaded
`portion 42. FIG. 7 shoWs ferrule 41 in cross-section having
`one end 44 including a ?ared portion 46 for mating engage
`ment With a corresponding chamfer in spacer 26. Thus, When
`
`Page 9 of 12
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`

`

`US 6,230,676 B1
`
`5
`ferrule 41 is press ?t into shaft 22, ?ared portion 46 captures
`and retains spacer 26 relative to shaft 22. In addition, ferrule
`41 includes slightly tapering side Walls 48 terminating at a
`second end 50. Side Walls 48 are tapered to facilitate
`insertion into bores 32, 34 and permit a Wider range of
`manufacturing tolerances that result in the same basic
`assembly conditions. Therefore, ferrule 41 provides an
`important function that alloWs a rocker arm supplier to fully
`pre-assemble a rocker arm shaft assembly that has all of the
`necessary parts, including fasteners, Which can then be
`shipped to an engine manufacturer’s plant Without losing
`component parts. Moreover, no parts are lost during han
`dling and installation into an engine.
`As best shoWn in FIG. 3, rocker arm 24 includes a main
`body 52 that is a generally planar, stamped, ?at plate having
`a valve contact end 54 and a push rod contact end 56. Also,
`main body 52 includes ?rst and second side surfaces 58, 60
`and top and bottom peripheral edges 62, 64. A central
`aperture 66 extends from main body 52 for receiving a
`tubular section 68 at any angle that is suitable for properly
`aligning rocker arm 24 With its associated engine valve and
`push rod. Angles range from 90° to any acute angle. Tubular
`section 68 has at least a portion extending laterally out
`Wardly from either one or both sides 58, 60 of main body 52.
`Tubular section 68 can be staked, braZed, laser Welded, or
`otherWise suitably connected to main body 52 to form a
`lever type rocker arm 24. In addition, main body 52 has a
`predetermined length that accurately positions rocker arm 24
`With an adjacent push rod and engine valve. By varying the
`angle of main body 52 relative to tubular section 68 and/or
`the length of main body 52, rocker arms 24 are able to be
`designed to precisely engage valves in almost any engine
`geometry layout, including offset valves.
`Valve contact end 54 of rocker arm 24 includes a loWer
`edge 70 having a convex valve contact surface 72 for
`contacting an end of a valve stem 74 as shoWn in FIG. 4.
`Valve contact surface 72 is preferably formed by plastically
`deforming material on loWer edge 60 such that portions 76
`extend laterally beyond the ?rst and second side surfaces 58,
`60 of main body 52.
`Push rod contact end 56 of rocker arm 24 includes a loWer
`edge 78 having a generally holloW semi-spherical recess 80
`formed therein such that a generally semi-spherical outer
`projection 82 is formed on each of the ?rst and second side
`surfaces 58, 60 of main body 52. Semi-spherical recess 80
`is adapted to receive a push rod 84 as shoW in FIG. 4.
`Preferably, push rod 84 is holloW to provide lubrication to
`semi-spherical recess 80 for reducing Wear caused by fric
`tion. Alternatively, if a solid push rod is utiliZed, then a
`mechanism for lubricating the interface should also be
`included.
`Top edge 62 of rocker arm 24 includes an apex 86 de?ned
`by at least tWo angled surfaces 88, 90 on either side.
`Optionally, but preferably, a lubricant bore 92 extends from
`apex 86 doWn through tubular section 68 for establishing
`?uid communication With a respective lubricant passageWay
`30 in central mounting shaft 22. Further, a lubrication
`groove 94 extends along top edge 62 from lubricant bore 92
`toWard ?rst end 54 to provide lubricant to convex valve
`contact surface 72. In addition, an optional lubrication
`groove can be provided along top edge 62 extending from
`lubricant bore 92 toWard second end 56, if desired.
`As shoWn in FIG. 4, lubricant passageWay 30 is prefer
`ably several times larger than rocker arm lubricant bore 92
`to permit lubricant to How freely to lubricant bore 92
`throughout the range of angular operating positions of
`
`10
`
`15
`
`25
`
`35
`
`55
`
`65
`
`6
`rocker arm 24. In addition, lubricant is able to How around
`the interface betWeen rocker arm 24 and central shaft 22. By
`providing a lubricant passageWay 30 through central shaft
`22 and up through a centrally located lubricant bore 92 in a
`rocker arm 24. Moreover, a more ef?cient lubrication system
`is provided by the present invention because lubricant is
`introduced at a high point of rocker arm 24 and travels a
`shorter distance to ?rst end 54 Where convex contact surface
`72 engages a valve stem 74.
`FIGS. 8 through 13 illustrate a second embodiment
`according to the present invention having a rocker arm
`assembly 120 that includes one or more rocker arms 124
`mounted onto a central mounting shaft 122 using a bearing
`element 123, including for example, a plurality of needle
`bearings, roller bearings, or bushing material. HoWever, any
`suitable bearing element can be used. Rocker arm assembly
`120 further includes a plurality of spacer sleeves 126 and
`one or more thrust Washers 128 disposed betWeen rocker
`arm 124 and spacer sleeve 126 to reduce Wear caused by side
`thrust loads. In contrast to thrust Washer 28, the second
`embodiment’s thrust Washer 128 includes one or more
`recesses or notches 129 provided on the inner diameter for
`providing a lubrication passageWay to bearing element 123,
`as described in greater detail beloW.
`Central mounting shaft 122 includes a plurality of rela
`tively short, hardened, solid shafts 125. Each solid shaft 125
`is connected to an adjoining solid shaft 125 by one of the
`spacer sleeves 126 that accommodates a pair of fasteners
`130. Each spacer sleeve 126 is generally a cylindrical
`tubular element that has a ?attened portion 132 that includes
`one or tWo through bores 134 for receiving fastener 130.
`Through bore 134 and through bore 133 in central shaft 122
`are generally the same siZe and are only slightly larger than
`fastener 130 to ensure a tight connection. Similar to the ?rst
`embodiment, it is contemplated that a ferrule 141 can be
`used to retain fastener 130, spacer sleeve 126 and central
`shaft 122. Alternatively, through bores 132 can be threaded
`to prevent unWanted removal or loss of fasteners 130 during
`shipping, handling, and installation. In addition, spacer
`sleeve 126 includes a split de?ned by a generally longitu
`dinal slot 136 for providing increased clamping load When
`fastener 130 is tightened. Slot 136 additionally de?nes a
`lubrication channel that collects and directs lubricant toWard
`bearing element 123.
`To provide interchangeability betWeen rocker arm assem
`bly 20 and rocker arm assembly 120, spacer sleeves 126
`have an outer diameter that is preferably substantially the
`same as the outside diameter of central mounting shaft 22 of
`rocker arm assembly 20. Thus, central mounting shaft 22
`and central mounting shaft 122 are designed to accurately ?t
`in the same semi-circular recesses 39 of toWers 38 for a
`given engine. The present invention alloWs an engine manu
`facturer to provide different types of rocker arm assemblies
`in a same basic engine design.
`Central mounting shaft 122 of the second embodiment has
`greater stiffness and improved hardenability. In addition,
`processing of relatively short shafts is easier because they
`are less susceptible to Warpage and bending during harden
`ing processes compared to a single relatively long solid
`shaft. Non-limiting examples of hardening processes that are
`contemplated to be used With the present invention include:
`heat treatment, induction hardening, through hardening,
`carburiZing, nitriding, etc. Therefore, the present invention
`alloWs tighter tolerances to be maintained because the
`relatively short shaft segments 125 have very loW distortion
`during manufacturing. Moreover, the overall rocker arm
`assembly 120 has a greater system stiffness than a single
`
`Page 10 of 12
`
`

`

`US 6,230,676 B1
`
`7
`solid shaft version. Improved stiffness increases bearing life
`and reduces the effects of cyclic loading.
`Lubrication for rocker arm assembly 120 is initially
`provided through a holloW push rod 140 as illustrated in
`FIG. 13. Next, lubricant ?oWs through a lubricant bore 142
`in rocker arm 124. Lubricant 142 is connected to a generally
`longitudinal lubricant groove 144 formed along a top edge
`146 of rocker arm 124. Lubricant groove 144 extends from
`lubricant bore 142 toWard valve contact end 147. In
`addition, as rocker arm 124 oscillates during operation,
`lubricant is throWn in multiple directions. Longitudinal slot
`136 in spacer sleeve 126 tends to collect lubricant, Which is
`able to How to bearing element 123 When one of the recesses
`129 of thrust Washer 128 is aligned With longitudinal slot
`136.
`Similar to rocker arm 24 of the ?rst embodiment, rocker
`arm 124 includes a main body 150 that is generally planar,
`stamped ?at plate having a central aperture 152 to receive a
`tubular section 154. Tubular section 154 can be attached to
`main body 150 at any desired angle by staking, braZing, laser
`Welding, or any other suitable attachment technique. Valve
`contact end 147 of rocker arm 124 has a convex valve
`contact surface 156 for contacting a valve stem 158. As
`illustrated in FIGS. 9 and 11, valve contact surface 156
`includes laterally extending portions 159 that extend later
`ally beyond side surfaces 160 of main body 150. In addition,
`push rod end 162 of rocker arm 124 has a loWer edge 164
`With a generally holloW semi-spherical recess 166 formed
`therein such that a generally semi-spherical outer projection
`168 is formed on respective side surfaces 160 of main body
`150. Semi-spherical recess 166 receives push rod 140.
`Although the present invention has been described having
`lubricant apertures located in the central region of the rocker
`arm as in the ?rst embodiment, it is alternatively contem
`plated that the lubricant aperture be located in the push rod
`end of the rocker arm and a holloW push rod is used for
`introducing lubricant to the rocker arm. In addition, although
`it is preferred to use a series of relatively short shafts that are
`connected together for the second embodiment of the
`present invention, it is also contemplated that a single solid
`shaft can be used in combination With the rocker arms of the
`present invention to achieve a suitable rocker arm assembly.
`Although the present invention can be fabricated using
`any suitable materials, preferably the rocker arm assembly is
`fabricated from metal, especially steel.
`Preferred embodiments of the present invention have been
`disclosed. Aperson of ordinary skill in the art Would realiZe,
`hoWever, that certain modi?cations Would come Within the
`teachings of this invention. Therefore, the folloWing claims
`should be studied to determine the true scope and content of
`the invention.
`What is claimed is:
`1. A rocker and assembly comprising:
`a central mounting shaft having spaced apart lubrication
`apertures;
`at least one bearingless rocker arm rotatably mounted to
`said central shaft;
`said rocker arm having a generally planar main body With
`?rst and second ends and ?rst and second side surfaces,
`a central aperture, a lubricant bore extending through
`said central aperture to a top portion of said main body
`
`10
`
`15
`
`25
`
`35
`
`45
`
`55
`
`65
`
`8
`and aligned With one of said lubrication apertures, and
`a lubrication groove formed along a top edge of said
`rocker arm and extending from said lubricant bore to
`said ?rst end of said rocker arm;
`said ?rst end of said rocker arm including a surface for
`contacting a valve stem, said surface extending later
`ally beyond at least one of said ?rst and second side
`surfaces of said planar main body, said lubrication
`groove delivering lubricant to said valve stem;
`said second end of said rocker arm including a generally
`holloW recess formed adjacent an edge of said planar
`main body such that an outer projection is formed on
`each of said ?rst and second side surfaces of said planar
`main body, said holloW recess provided for receiving an
`end of a push rod;
`a tubular section of said rocker arm surrounding said
`central shaft and intersecting said main body at a
`predetermined angle such that said rocker arm is posi
`tioned at a non-perpendicular angle With respect to said
`central shaft; and
`Wherein said central mounting shaft is an elongated
`holloW shaft having spaced apart lubrication apertures
`that are aligned With, and provide lubricant to said
`lubricant bore of said rocker arm.
`2. The rocker arm assembly of claim 1, Wherein said
`tubular section is positioned in said central aperture, said
`tubular section directly contacting an end portion of said
`central mounting shaft With a slip ?t condition.
`3. The rocker arm assembly of claim 1, further comprising
`a ferrule and a spacer connected to said central mounting
`shaft, said ferrule having a predetermined inside diameter
`for limiting movement of a fastener and a predetermined
`outside diameter for retaining said spacer on said central
`mounting shaft.
`4. The rocker arm assembly of claim 1, Wherein a spacer
`is secured to said central shaft and positioned adjacent to
`said rocker arm to position said rocker arm With respect to
`said central shaft.
`5. A rocker arm assembly comprising:
`a central mounting shaft having a plurality of spaced apart
`through bores;
`at least one bearingless rocker arm having a central
`aperture for rotatably mounting said rocker arm to said
`central shaft;
`a lubricant bore provided in said rocker arm and extend
`ing through said rocker arm to a top portion of said
`rocker arm and ?uidly connected to said central aper
`ture;
`a lubrication groove extending from said lubrication bore
`and extending along said top portion of said rocker arm
`toWard a ?rst end of said rocker arm; and
`at least one spacer having a through bore for receiving a
`fastene

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