EP1992795A2 - Suiveur de came de contact à rouleau à deux étapes - Google Patents

Suiveur de came de contact à rouleau à deux étapes Download PDF

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Publication number
EP1992795A2
EP1992795A2 EP08154624A EP08154624A EP1992795A2 EP 1992795 A2 EP1992795 A2 EP 1992795A2 EP 08154624 A EP08154624 A EP 08154624A EP 08154624 A EP08154624 A EP 08154624A EP 1992795 A2 EP1992795 A2 EP 1992795A2
Authority
EP
European Patent Office
Prior art keywords
shaft
slider
slider arm
follower assembly
finger follower
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP08154624A
Other languages
German (de)
English (en)
Other versions
EP1992795A3 (fr
Inventor
Nick J. Hendriksma
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Delphi Technologies Inc
Original Assignee
Delphi Technologies Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Delphi Technologies Inc filed Critical Delphi Technologies Inc
Publication of EP1992795A2 publication Critical patent/EP1992795A2/fr
Publication of EP1992795A3 publication Critical patent/EP1992795A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
    • F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
    • F01L13/0036—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12—Transmitting gear between valve drive and valve
    • F01L1/18—Rocking arms or levers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12—Transmitting gear between valve drive and valve
    • F01L1/18—Rocking arms or levers
    • F01L1/181—Centre pivot rocking arms
    • F01L1/182—Centre pivot rocking arms the rocking arm being pivoted about an individual fulcrum, i.e. not about a common shaft
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12—Transmitting gear between valve drive and valve
    • F01L1/18—Rocking arms or levers
    • F01L1/185—Overhead end-pivot rocking arms
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
    • F01L13/0005—Deactivating valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/12—Transmitting gear between valve drive and valve
    • F01L1/18—Rocking arms or levers
    • F01L2001/186—Split rocking arms, e.g. rocker arms having two articulated parts and means for varying the relative position of these parts or for selectively connecting the parts to move in unison
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L2305/00—Valve arrangements comprising rollers

Definitions

  • the present invention relates to roller finger followers used for variable valve actuation in overhead cam type internal combustion engines; and more particularly, to a roller finger follower assembly having a body supportive of an axle shaft for dual outboard rollers for following a corresponding pair of cam lobes, and a central slider arm for following a central cam lobe between the pair of lobes; and most particularly, to such an assembly wherein the slider is pivotably mounted on the axle shaft.
  • Roller Finger Followers are widely used in overhead cam internal combustion engines to sequentially open and close the cylinder intake and exhaust valves.
  • the RFF assembly serves to transfer and translate rotary motion of a camshaft eccentric lobe into a pivotal motion of the RFF assembly to thereby open and close an associated valve.
  • valves may be opened to only a low lift position to conserve fuel, and that at times of high torque demand, the valves may be opened wider to a high lift position to admit more fuel. It is known in the art to accomplish this by de-activating a portion of the valve train associated with pre-selected cylinders in any of various ways.
  • One way is by providing a special two-step RFF assembly having a variably activatable and deactivatable central slider arm which may be positioned for contact with a high lift lobe of the camshaft.
  • Such a two-step RFF typically is also configured with rollers disposed at each side of the slider arm for contact with low lift lobes of the cam shaft on either side of the high-lift lobe.
  • the two-step RFF causes low lift of the associated valve when the slider arm of the RFF is in a deactivated (unlatched) mode, and high lift of the associated valve when the slider arm of the RFF is an activated (latched) mode to transmit motion of the high lift lobe of the camshaft.
  • a typical prior art two-step roller finger follower is disclosed in US Patent No. 6,755,167 B2, issued June 29, 2004 , the relevant disclosure of which is incorporated herein by reference.
  • an elongate body having first and second side members defines coaxially disposed shaft orifices.
  • a pallet end and a socket end interconnect with the first and second side members to define a central slider arm aperture and a latch pin channel.
  • the socket end is adapted to mate with a mounting element such as an hydraulic lash adjuster, and the pallet end is adapted to mate with a valve stem, pintle, lifter, or the like.
  • a slider arm for engaging a high-lift cam lobe is disposed in the slider arm aperture and has first and second ends, the first end of the slider arm being pivotally mounted to the pallet end of the body and the second end defining a slider tip for engaging an activation/deactivation latch pin.
  • the latch pin is slidably disposed in the latch pin channel, the latch pin having a nose section for selectively engaging the slider tip.
  • a spool-shaped roller comprising a shaft and opposed roller elements fixedly attached to ends of the shaft is rotatably disposed in the shaft orifices, the roller being adapted to cause the RFF body to follow the surface motion of a low-lift cam lobes.
  • the shaft is journalled in roller or needle bearings which extend between and through both the first and second shaft orifices, being thus exposed to normal copious oil flow through central regions of the RFF.
  • a coil torsion spring mounted on the slider arm pivot pin urges the slider into continuous contact with the central cam lobe.
  • a drawback of all such prior art two-step RFF assemblies is that the mass of the central slider, and therefore the moment of rotational inertia, is undesirably high, which increases the force requirements of the lost motion and valve springs.
  • Still another drawback is that the range of lost motion of the central slider is constrained by practical limits of mechanical strength imposed by the arcuate slot in the central slider for accommodating the axle of the low-lift rollers.
  • Still another drawback is that the number of components is undesirably large, resulting in relatively high component manufacturing and assembly costs.
  • Still another drawback is that provision for a rotational stop to limit leakdown of an associated HLA requires special manufacturing and assembly components and procedures.
  • WO 2007/035673 A2 discloses a finger follower assembly having a central roller follower for following a central cam lobe, the central roller follower being mounted on a shaft passing through the assembly body and supporting a linked pair of lateral slider followers for following dual cam lobes on either side of the central lobe.
  • the lateral slider followers are mounted eccentrically on the shaft and thus may be rotated between a latched high-lift (valve actuating) position and an unlatched low-lift (valve deactivating or lost motion) position.
  • the lateral slider followers are latched and unlatched by a hydraulic piston latching mechanism in the assembly body.
  • the central roller follower is engaged for low-lift or no-lift valve events
  • the lateral sliders are engaged for high-lift valve events and are disengaged for low-lift or no-lift valve events.
  • a pallet end and a socket end interconnect with the first and second side members to define a slider arm aperture and a latch pin channel.
  • the socket end is adapted to mate with a mounting element such as an hydraulic lash adjuster, and the pallet end is adapted to mate with a valve stem, pintle, lifter, or the like.
  • a spool-shaped roller comprising a shaft and opposed roller elements attached to the shaft is disposed in the shaft orifices, the rollers being adapted to follow the surface motion of the low-lift cam lobes.
  • the shaft is journalled in roller or needle bearings which extend between and through both the first and second shaft orifices, being thus exposed to normal copious oil flow through central regions of the RFF.
  • a slider arm for engaging a high-lift cam lobe is disposed in the slider arm aperture and is pivotally mounted on a common axis with the roller shaft and includes a slider tip for engaging an activation/deactivation latch pin.
  • the latch pin is slidably and at least partially disposed in the latch pin channel and has a nose section for extending from the channel to selectively engage the slider tip, to switch modes of the RFF assembly.
  • prior art two-step RFF assembly 10 is substantially as shown in US Patent No. 6,755,167 B2 .
  • Pallet end 12 of prior art RFF 10 is provided for engaging a valve stem 11 and socket end 14 is provided for engaging the hemispherical head of a hydraulic lash adjuster 15.
  • RFF 10 includes body assembly 16, slider arm assembly 18, spool roller assembly 20, lost motion spring 22, and latch assembly 24.
  • Body assembly 16 includes elongate body 26 and roller bearing 28 disposed in bearing orifices 30.
  • Elongate body 26 includes a slider arm aperture 32 bounded by body side walls 34 defining bearing orifice 30 therethrough.
  • the diameter of bearing orifice 30 is sized to press-fittedly receive roller bearings 28.
  • a cross-shaft 36 is rotatably disposed in bearing 28 and is supportive of roller 38 on the end thereof for following a low-lift cam lobe.
  • a second body sidewall, bearings, roller, and the like are all present in an actual RFF assembly but are not visible in the cross-sectional view shown in FIG. 1 .
  • Slider arm assembly 18 includes slider arm 40 and slider shaft 42, having mutual axes 43, for pivotably attaching arm 40 to body 26.
  • Slider arm 40 defines slider surface 44 for following a high-lift cam lobe, and further includes slider tip 46 and elongated roller shaft clearance aperture 48.
  • prior art slider arm assembly because it pivots from shaft 42, includes substantial mass between aperture 48 and shaft 42 which exists for no purpose other than to allow the slider arm assembly to pivot from a pivot axis disposed over valve stem 11 and pallet end 12. It is an important benefit of the improved two-step RFF assembly as disclosed and claimed herein that most of this portion of a slider arm assembly is eliminated and therefore the rotational mass of an improved slider arm assembly, as described below, is substantially reduced.
  • latch pin axis 54 is substantially perpendicular to, and passes through, pivot pin axis 43.
  • axis 54 lies on a radius 55 of the rotational arc of slider arm 40 (i.e., axis 54 forms an included angle 57 of 180° with an extension of radius 55), causing slider tip 46 to be traveling in a direction substantially orthogonal to axis 54 at the point of engagement with latch pin 52.
  • a valve train 100 for an internal combustion engine 102 includes a valve 104, either intake or exhaust, having a valve stem 11 as in FIG. 1 engaged by a pallet end 112 of a two-step RFF assembly 110 in accordance with the invention.
  • a hydraulic lash adjuster 15 as in FIG. 1 is mounted in the head 106 of engine 102 for supporting RFF assembly 110 via a socket 114 therein.
  • a camshaft 90 includes a low-lift cam lobe 92 for actuating RFF assembly 110 via an outboard roller 138, and further includes a high-lift cam lobe 94 for actuating RFF assembly 110 via a central slider arm 140 of slider arm assembly 118.
  • the slider arm is mounted on and pivots about the same axis as the outboard rollers, thereby shortening both the length of the slider arm and the RFF body.
  • Improved RFF assembly 110 includes body assembly 116, central slider arm 140, spool roller assembly 120, lost motion spring 122, and latch assembly 124.
  • Body assembly 116 includes elongate body 126 and roller bearings 128.
  • Elongate body 126 includes a slider arm aperture 132 bounded by body side walls 134 defining bearing orifices 130 formed in bosses 131 of sidewalls 134.
  • the diameter of bearing orifice 130 is sized to press-fittedly receive roller bearings 128.
  • a cross-shaft 136 is rotatably disposed in bearings 128 and is supportive of rollers 138 on the ends thereof for following first and second outboard low-lift cam lobes 92 ( FIG. 2 ).
  • Slider arm 140 defines a slider surface 144 for following high-lift cam lobe 94, and further includes slider tip 146 ( FIG. 2 ), for engaging a latch pin 161, and roller shaft apertures 148.
  • Slider arm 140 is disposed on a slider bushing 142 that itself is mounted in the sidewall bearing orifices.
  • Bushing 142 preferably includes ports 143 to allow oil to enter the bushing and move along the surface of shaft 136 to help in lubricating bearings 128.
  • Slider arm 140 may be fixedly mounted on bushing 142 which rotates within the sidewall bearing orifices; or slider arm 140 may be rotatably mounted on bushing 142 which is fixed to the sidewall bearing orifices.
  • slider arm 140 is rotatable about the axis of cross-shaft 136 and with respect to RFF body 126.
  • RFF assembly 110 as noted above includes a bias spring 122 which engages both RFF body 126 and slider arm 140 to urge the slider arm into continuous contact with high-lift cam lobe 94, as shown in FIG. 2 .
  • Slider arm 140 may thus rotate until stopped by rotational limiters 147 extending from slider arm 140 that engage RFF body 126, thus preventing excessive leakdown of HLA 15 ( FIG. 2 ).
  • surface 144 of slider arm 140 comprises a compound surface comprising a plurality of surface portions which may be planar but preferably are arcuate.
  • a first surface portion 144a is formed at a larger radius 151 a of a circle 153a as shown in FIGS. 9 and 10 .
  • a second surface portion 144b is formed at a smaller radius 151 b of a circle 153b contained within circle 153a, the two surface portions being tangentially joined at line 155.
  • a portion 157 of circle 153a is not present in slider arm 140, thereby defining a relieved area 159 of the slider arm into which the eccentric nose of cam lobe 94 extends during rotation of the camshaft when RFF assembly 110 is in lost motion (valve deactivation) mode, thereby reducing the required rotational lost motion of slider arm 140.
  • slider arm 140 pivots about axis 161 of shaft 136, and cam lobe 94 engages slider arm 140 on surface 144b.
  • slider arm 140 does not rotate about axis 161 but rather is latched at lip 146 to latch pin 161 and thus is integral with RFF body 126.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
  • Valve Device For Special Equipments (AREA)
EP08154624A 2007-05-16 2008-04-16 Suiveur de came de contact à rouleau à deux étapes Withdrawn EP1992795A3 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US11/803,910 US20080283003A1 (en) 2007-05-16 2007-05-16 Two-step roller finger cam follower

Publications (2)

Publication Number Publication Date
EP1992795A2 true EP1992795A2 (fr) 2008-11-19
EP1992795A3 EP1992795A3 (fr) 2010-03-24

Family

ID=39739248

Family Applications (1)

Application Number Title Priority Date Filing Date
EP08154624A Withdrawn EP1992795A3 (fr) 2007-05-16 2008-04-16 Suiveur de came de contact à rouleau à deux étapes

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US (1) US20080283003A1 (fr)
EP (1) EP1992795A3 (fr)

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10415439B2 (en) 2008-07-22 2019-09-17 Eaton Intelligent Power Limited Development of a switching roller finger follower for cylinder deactivation in internal combustion engines
US20190309663A9 (en) 2008-07-22 2019-10-10 Eaton Corporation Development of a switching roller finger follower for cylinder deactivation in internal combustion engines
WO2015134466A1 (fr) 2014-03-03 2015-09-11 Eaton Corporation Dispositif d'actionnement de soupape et son procédé de fabrication
US9708942B2 (en) * 2010-03-19 2017-07-18 Eaton Corporation Rocker arm assembly and components therefor
US9228454B2 (en) 2010-03-19 2016-01-05 Eaton Coporation Systems, methods and devices for rocker arm position sensing
US9938865B2 (en) 2008-07-22 2018-04-10 Eaton Corporation Development of a switching roller finger follower for cylinder deactivation in internal combustion engines
US10087790B2 (en) 2009-07-22 2018-10-02 Eaton Corporation Cylinder head arrangement for variable valve actuation rocker arm assemblies
US11181013B2 (en) 2009-07-22 2021-11-23 Eaton Intelligent Power Limited Cylinder head arrangement for variable valve actuation rocker arm assemblies
US9194261B2 (en) 2011-03-18 2015-11-24 Eaton Corporation Custom VVA rocker arms for left hand and right hand orientations
US9885258B2 (en) 2010-03-19 2018-02-06 Eaton Corporation Latch interface for a valve actuating device
US9874122B2 (en) 2010-03-19 2018-01-23 Eaton Corporation Rocker assembly having improved durability
USD791190S1 (en) 2015-07-13 2017-07-04 Eaton Corporation Rocker arm assembly
USD833482S1 (en) 2015-07-13 2018-11-13 Eaton Corporation Rocker arm
WO2017024249A1 (fr) * 2015-08-05 2017-02-09 Eaton Corporation Culbuteur de commutation pour la recirculation interne de gaz d'échappement
DE112017004562T5 (de) * 2016-10-07 2019-05-23 Eaton Intelligent Power Limited Geschlossener e-fuss
WO2020020492A1 (fr) * 2018-07-27 2020-01-30 Eaton Intelligent Power Limited Culbuteur de désactivation verrouillé par pivot central
US10519817B1 (en) * 2018-08-29 2019-12-31 Delphi Technologies Ip Limited Switchable rocker arm with lash adjustment and travel stop

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6755167B2 (en) 2002-02-26 2004-06-29 Delphi Technologies, Inc. Two-step roller finger cam follower having spool-shaped low-lift roller
US6925978B1 (en) 2004-08-24 2005-08-09 Delphi Technologies, Inc. Two-step roller finger cam follower having angled lock pin
US20060249110A1 (en) 2005-05-09 2006-11-09 Fernandez Hermes A Two-step roller finger follower
WO2007035673A2 (fr) 2005-09-16 2007-03-29 Timken Us Corporation Ensemble a doigt de poussee de commutation

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0286389A3 (fr) * 1987-04-07 1989-02-15 The British Internal Combustion Engine Research Institute Limited Dispositif pour régler la distribution d'une soupape
US6997152B2 (en) * 2002-04-29 2006-02-14 Delphi Technologies, Inc. Lock-pin cartridge for a valve deactivation rocker arm assembly
WO2005093224A1 (fr) * 2004-03-03 2005-10-06 Timken Us Corporation Ensemble de suiveur a faible friction de commutation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6755167B2 (en) 2002-02-26 2004-06-29 Delphi Technologies, Inc. Two-step roller finger cam follower having spool-shaped low-lift roller
US6925978B1 (en) 2004-08-24 2005-08-09 Delphi Technologies, Inc. Two-step roller finger cam follower having angled lock pin
US20060249110A1 (en) 2005-05-09 2006-11-09 Fernandez Hermes A Two-step roller finger follower
WO2007035673A2 (fr) 2005-09-16 2007-03-29 Timken Us Corporation Ensemble a doigt de poussee de commutation

Also Published As

Publication number Publication date
EP1992795A3 (fr) 2010-03-24
US20080283003A1 (en) 2008-11-20

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