EP4375491A1 - Train de soupapes - Google Patents

Train de soupapes Download PDF

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Publication number
EP4375491A1
EP4375491A1 EP22208873.4A EP22208873A EP4375491A1 EP 4375491 A1 EP4375491 A1 EP 4375491A1 EP 22208873 A EP22208873 A EP 22208873A EP 4375491 A1 EP4375491 A1 EP 4375491A1
Authority
EP
European Patent Office
Prior art keywords
cam
distribution apparatus
distribution
crossbow
bearing
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.)
Pending
Application number
EP22208873.4A
Other languages
German (de)
English (en)
Inventor
Umberto Borile
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.)
Marik Srl
Original Assignee
Marik Srl
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 Marik Srl filed Critical Marik Srl
Priority to EP22208873.4A priority Critical patent/EP4375491A1/fr
Publication of EP4375491A1 publication Critical patent/EP4375491A1/fr
Pending 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
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/30—Valve-gear or valve arrangements, e.g. lift-valve gear characterised by the provision of positively opened and closed valves, i.e. desmodromic 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
    • F01L1/02—Valve drive
    • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
    • F01L1/047—Camshafts
    • 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
    • F01L1/14—Tappets; Push rods
    • F01L1/146—Push-rods
    • 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
    • F01L1/02—Valve drive
    • F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
    • F01L1/047—Camshafts
    • F01L2001/0476—Camshaft bearings
    • 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
    • F01L2301/00—Using particular materials

Definitions

  • the present invention relates to a distribution apparatus for engines, and an engine comprising such a distribution apparatus.
  • two-stroke or four-stroke engines are equipped with a cylinder head that, together with the piston and the cylinder, creates the combustion chamber.
  • the intake and exhaust valves, necessary for the completion of the phases of the engine cycle, are housed in the cylinder head.
  • the valves are driven by camshafts, which push them down towards the combustion chamber.
  • the camshafts may be moved by means of rods, a chain, a toothed belt or gears, typically a cascade of gears, or else using a shaft and two bevel wheels.
  • the step of raising the valves into the seats thereof is performed by springs, which may be made of steel, titanium, or be pneumatic.
  • the desmodromic distribution does not use return springs for the movement of the valves.
  • the desmodromic distribution uses rocker arms for both opening and closing the valves, and a small spring to ensure the closure of the valve.
  • rocker arms are replaced with a double camshaft that uses the cam directly above the valve head together with the intersection of a cup with a calibrated pad.
  • it is necessary to lubricate the area where the cam rubs against the pad in order to reduce the sliding friction that is generated, and it is also necessary to dispose of the heat generated using special radiators.
  • a distribution apparatus for an engine comprising at least one intake valve and at least one exhaust valve; said apparatus comprising movement means for said at least one intake valve and for said at least one exhaust valve; characterized in that said movement means comprise a first crossbow element and a second crossbow element to which said at least one intake valve and said at least one exhaust valve are respectively connected, arranged in a direction substantially perpendicular to said at least one intake valve and to said at least one exhaust valve; said first crossbow element and said second crossbow element being connected at each end with respective heads of distribution rods; said distribution rods being arranged in correspondence with a foot thereof, opposite to said head with at least one bearing; each of said bearings being in connection with respective cam means suitable for being put into rotation by a drive shaft for the movement of said at least one said inlet valve and said at least one exhaust valve.
  • the present disclosure further refers to the prior art for the implementation thereof, with respect to those detailed characteristics which are not described, such as, for example, elements of minor importance that are usually used in the prior art in solutions of the same type.
  • a distribution apparatus for engines according to the present invention is shown in Figure 1 with the reference 12.
  • the distribution apparatus 12 comprises at least one intake valve 14, 16, at least one exhaust valve 18, 20, and movement means 22 for the at least one intake valve 14, 16 and for the at least one exhaust valve 18, 20.
  • the movement means 22 comprise a first crossbow element 24 and a second crossbow element 26 to which the at least one intake valve 14, 16 and the at least one exhaust valve 18, 20 are connected, respectively, and which are arranged in a direction substantially perpendicular to the at least one intake valve 14, 16 and to the at least one exhaust valve 18, 20.
  • the first crossbow element 24 and the second crossbow element 26 are connected at each end 242, 244; 262, 264 with respective heads 282, 302, 322, 342 of distribution rods 28, 30, 32, 34.
  • the distribution rods 28, 30, 32, 34 are arranged in correspondence with a foot 282, 302, 322, 342 thereof, opposite the relevant head 284, 304, 324, 344 with at least one bearing 36, 38.
  • Each of the bearings 36, 38 is in connection with respective cam means 40, 42, 44, 46 suitable for being put into rotation by a drive shaft 48 for moving the at least one intake valve 14, 16 and the at least one exhaust valve 18, 20.
  • the engine may be of the type comprising at least one cylinder on which two intake valves 14, 16 and two exhaust valves 18, 20 are arranged.
  • this is a single-cylinder engine for a motorcycle.
  • the principles of the present invention may also be applied, for example, to multi-cylinder engines facing forward or with a V-shaped arrangement.
  • the at least one intake valve 14, 16 and the at least one exhaust valve 18, 20 are respectively arranged on the first crossbow element 24 and on the second crossbow element 26 by means of forks 142, 162, 182, 202.
  • the fork 142, 162, 182, 202 may be fixed to the relevant crossbow element whilst the valve may be rotatably fixed between the ends of the fork.
  • the at least one intake valve 14, 16 and the at least one exhaust valve 18, 20 are substantially parallel with respect to the respective distribution rods 28, 30, 32, 34.
  • the first crossbow element 24 and the second crossbow element 26 may have a diameter of between 4 and 6 mm, preferably around 5 mm.
  • the ends 242, 244; 262, 264 of the first crossbow element 24 and the second crossbow element 26 may be made using a tube, into which the distribution rod 28, 30, 32, 34 is engaged.
  • the ends 242, 244; 262, 264 of the first crossbow element 24 and the second crossbow element 26 may be locked relative to the relevant distribution rod 28, 30, 32, 34 in a manner known to a person skilled in the art.
  • first crossbow element 24 and the second crossbow element 26 may be made of harmonic titanium.
  • first crossbow element 24 and the second crossbow element 26 may be made of a different metal of harmonic type.
  • each crossbow element 24, 26 may be implemented by means of two crossbow element rods 241, 243 which are side by side and substantially parallel to one another.
  • crossbow element 24 As may be seen in Figure 11 , in which only the crossbow element 24 is shown, the latter may be made by using two crossbow element rods 241, 243 which are side by side and substantially parallel.
  • the two crossbow element rods may be made with the same features as the single crossbow element indicated above.
  • the two crossbow element rods 241, 243 may be made of harmonic titanium.
  • valve 18 may be arranged with a threaded head suitable for being connected to an upper fork 182 and a lower fork 183 for adjusting the valve 18 itself, leaving the rotation thereof free.
  • damping elements suitable for damping the vibrations of the crossbow rods 241, 243 may be arranged between the two crossbow element rods 241, 243.
  • the distribution rods 28, 30, 32, 34 may be made using a tube.
  • the distribution rods 28, 30, 32, 34 may be made using a tube having an outer diameter of around 10 mm, and an inner diameter of around 8 mm. These dimensions are clearly given for explanatory and non-limiting purposes only.
  • the distribution rods 28, 30, 32, 34 may be made of harmonic titanium. In alternative embodiments, they may be made of a different metal.
  • distribution rods 28, 30, 32, 34 are advantageous at least in that:
  • the distribution rods 28, 30, 32, 34 are suitable for moving in an alternating rectilinear motion, and may be guided by a pair of opposite concave bearings 90.
  • the cam means 40, 42, 44, 46 may comprise, for each bearing 36, 38, an opening cam 402, 422 adapted to interact with the relevant bearing 36, 38 to open the at least one intake valve 14, 16 or the at least one exhaust valve 18, 20, and a closing cam 404, 424 adapted to interact with the relevant bearing 36, 38 to close the at least one intake valve 14, 16 or the at least one exhaust valve 18, 20.
  • each bearing 36, 38 may be interposed between two respective cams 402, 404 and 422, 424.
  • the bearing 36, 38 may be interposed between an opening cam 402, 422 adapted to push the bearing 36, 38 towards the engine crankcase, so as to move the valve inside the combustion chamber, and a closing cam 404, 424 adapted to push the bearing 36, 38 in the opposite direction with respect to the engine crankcase, so that the valve moves in contact with the seat, so that it may close.
  • the opening cam 402, 422 may be provided with a radial protrusion 410, while the closing cam 404, 424 may be provided with a radial recess 412.
  • the opening cam 402, 422 and the closing cam 404, 424 are adapted to always be in contact with the relevant bearing 36, 38 during the movement thereof.
  • each opening cam 402, 422 and each closing cam 404, 424 may be keyed to a relevant shaft 403, 423, 405, 425, on which a relevant cam toothed wheel 406, 407, 426, 427 is also keyed.
  • cam toothed wheels 406, 407, 426, 427 The function of the cam toothed wheels 406, 407, 426, 427 is to receive motion and rotate the respective cams.
  • a central toothed wheel 58 adapted for receiving motion directly or indirectly from the drive shaft may be provided, wherein the central toothed wheel 58 engages simultaneously with the four cam toothed wheels 406, 407, 426, 427.
  • the rotation of the cams may be synchronized according to specific needs, by modifying the engagement between the central toothed wheel 58 and the toothed wheels 406, 407, 426, 427 of the cams.
  • the transmission ratio between the cam and the drive shaft will be 2:1.
  • the opening cams 402, 422 and the closing cams 404 may be contained within respective box elements 60, 62, 64, 66 which, in addition to at least partially containing the cams 402, 422, 404, 424 during the movement thereof, may be suitable for creating support surfaces for the cam shafts 403, 423, 405, 425.
  • the foot 282, 302, 322, 342 of the distribution rods 28, 30, 32, 34 may be shaped like a fork so that the bearing 36, 38 may be supported between the prongs of the forks.
  • slotted openings 68 may be made on the side profile of the fork to allow the fork to slide with respect to the shafts on which the opening cams are arranged.
  • the distribution rods 28, 30, 32, 34 may be arranged at the foot 282, 302, 322, 342 thereof with two bearings 36, 361; 38, 381 which are side by side and arranged on the same axis.
  • the foot 282, 302, 322, 342 of the distribution rods may be shaped like a fork so that a first bearing 36 is connected to one prong of the fork, and a second bearing 361 is connected to a second prong of the fork.
  • the cam means 42 may comprise a double cam element 70, 72 for each distribution rod 28, 30, 32, 34.
  • the double cam element 70, 72 may have a rotational axis that is substantially parallel to the rotational axis of the drive shaft 48.
  • the double cam element 70, 72 is arranged with a substantially cylindrical body having an opening cam 702, 722 and a closing cam 704, 724 side by side.
  • the double cam element 70, 72 is arranged on one side with an external abutment surface for a bearing defining the opening cam 702, 722 and on the opposite side with an internal abutment surface defining the closing cam 704, 724.
  • Figures 8 and 9 show a detail of the sliding of the bearing with respect to the profile of the closing cam 724.
  • only one bearing suitable for sliding in a track between an inner cam and an outer cam may be arranged at the foot of the distribution rod.
  • a double cam element toothed wheel 730 may be implemented that is suitable for engaging with a corresponding shaft toothed wheel 735 arranged on the drive shaft 48 or by means of gears.
  • the distribution apparatus according to the present invention is affected by lower working losses compared to the distribution apparatus of the prior art.
  • the distribution apparatus according to the present invention may have a contained head height, going from about 150 mm of a normal head to about 80 mm.
  • the distribution apparatus according to the present invention is more balanced than the distribution apparatus of the prior art, since there are no weight components or rotations of elements in the vicinity of the cylinder head. In fact, all of the rotations are arranged at the base of the cylinder.
  • the distribution apparatus does not use belts or chains and, above all, does not use rocker arms. Consequently, the periodic replacement of a belt or chain need not be performed.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
EP22208873.4A 2022-11-22 2022-11-22 Train de soupapes Pending EP4375491A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP22208873.4A EP4375491A1 (fr) 2022-11-22 2022-11-22 Train de soupapes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP22208873.4A EP4375491A1 (fr) 2022-11-22 2022-11-22 Train de soupapes

Publications (1)

Publication Number Publication Date
EP4375491A1 true EP4375491A1 (fr) 2024-05-29

Family

ID=84981250

Family Applications (1)

Application Number Title Priority Date Filing Date
EP22208873.4A Pending EP4375491A1 (fr) 2022-11-22 2022-11-22 Train de soupapes

Country Status (1)

Country Link
EP (1) EP4375491A1 (fr)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7146948B1 (en) * 2005-09-30 2006-12-12 Clinton D Eells Valve lifting arrangement
WO2008149316A2 (fr) * 2007-06-07 2008-12-11 Manousos Pattakos Actionnement de soupape variable desmodromique

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7146948B1 (en) * 2005-09-30 2006-12-12 Clinton D Eells Valve lifting arrangement
WO2008149316A2 (fr) * 2007-06-07 2008-12-11 Manousos Pattakos Actionnement de soupape variable desmodromique

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