Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
  • F16F15/10—Suppression of vibrations in rotating systems by making use of members moving with the system
  • F16F15/14—Suppression of vibrations in rotating systems by making use of members moving with the system using masses freely rotating with the system, i.e. uninvolved in transmitting driveline torque, e.g. rotative dynamic dampers
  • F16F15/1407—Suppression of vibrations in rotating systems by making use of members moving with the system using masses freely rotating with the system, i.e. uninvolved in transmitting driveline torque, e.g. rotative dynamic dampers the rotation being limited with respect to the driving means
  • F16F15/1414—Masses driven by elastic elements
  • F16F15/1435—Elastomeric springs, i.e. made of plastic or rubber
  • F16F15/1442—Elastomeric springs, i.e. made of plastic or rubber with a single mass
• • 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
• • 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
  • F01L1/024—Belt drive
• • 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
  • F01L1/053—Camshafts overhead type
  • F01L2001/0537—Double overhead camshafts [DOHC]
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B1/00—Engines characterised by fuel-air mixture compression
  • F02B1/02—Engines characterised by fuel-air mixture compression with positive ignition
  • F02B1/04—Engines characterised by fuel-air mixture compression with positive ignition with fuel-air mixture admission into cylinder
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
  • F02B2275/06—Endless member is a belt
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
  • F02B2275/18—DOHC [Double overhead camshaft]

Definitions

• the subject invention concerns an arrangement in a multi-cylinder internal combustion engine comprising at least one cam shaft which is driven by a crankshaft via a transmission, said transmission comprising at least one driving toothed pulley positioned at the front end of the crankshaft, one driven toothed pulley for each cam shaft, and at least one toothed belt which is wrapped about the driving and the driven toothed pulleys.
• the frequency of such moment variations is at its peak at a value corresponding to three times the r.p.m. in the case of a sex-cylinder internal combustion engine and to twice the r.p.m. in the case of a four-cylinder engine. Consequently, the cam shaft/shafts expose(s) the toothed belt/belts to modulated (not statical) stress in the longitudinal belt direction, known as excitation.
• the toothed belt/belts possess(es) a certain rigidity, denominated "K”
• the cam shaft/shafts and their associated toothed pulleys possess(es) a predetermined moment of inertia "I”
• an oscillation system of the first order having the following resonance frequency
• the main purpose of the invention therefore is to increase the life of the toothed belt/belts, and this purpose is achieved by means of providing at least one driven toothed pulley with an oscillation damper which is connected to the pulley.
• Fig. 1 is a schematical front view of a internal combustion engine equipped with two cam shafts, each one of which is associated with a driven toothed pulley having an oscillating damper integrated therein in accordance with a first integration method
• Fig. 2 shows one of the driven toothed pulleys of Fig. 1 in a view from behind and on an enlarged scale
• Fig. 3 is a sectional view along line III-III of Fig 2 and
• Figs. 4 and 5 show alternative methods of integratin the oscillating damper with its associated driven toothed pulley.
• the internal internal combustion engine 1 illustrate in Fig. 1 in a schematical front view is, in accordance with the embodiment illustrated, an in-line six-cylinder Otto engine but also other engine varieties are possible, as long as they have at least one cam shaft 3 which is driven by a crankshaft 2 via a transmission, the latter comprising at least one driving toothed pulley 4 positioned at the front end of the crankshaft 2, one driven toothed pulley 5 for each cam shaft 3, and at leas one toothed belt 6 wrapped around the driving and driven toothed pulleys 4, 5.
• the engine 1 in accordance with Fig. 1 comprises a tightening device 7 including a tightening roller 8 designed to automatically tighten the toothed belt 6, a water pump (not shown) which is driven via a toothed pulley 9, and a free-running deflection roller 10
• a tightening device 7 including a tightening roller 8 designed to automatically tighten the toothed belt 6, a water pump (not shown) which is driven via a toothed pulley 9, and a free-running deflection roller 10
• Components 7-10 do not form part of the subject invention and therefore will not be described herein further.
• the two driven toothed pulleys 5 illustrated in Fig. 1 have an identical construction, for which reason only one of them will be decribed in closer detail with reference to Figs. 2-5.
• This driven toothed pulley 5 preferably is made of metal or other rigid material and is formed with a toothe rim 11 the teeth 12 of which are arranged for positive engagement with the teeth 13 of the toothed belt 6.
• the toothed pulley 5 comprises a hub 14 by mean of which the driven toothed wheel is mounted on the associated cam shaft 3, and a web portion 15 extending between the toothed rim 11 and the hub 14.
• the web portion 15 has a considerably reduced thickness dimension compared with the toothed rim 11 and also compared with the hub 14. The web portion 15 thus is positioned adjacent the face of the driven toothed pulley 5 which, when the pulley 5 is mounted on its associated cam shaft 3, is turned towards the front as seen in Fig. 1.
• annular recess 16 is formed internally of the toothed rim 11, i.e. a recess defined by the rim, the web portion 15, and the hub 14.
• An oscillation damper is connected to the driven toothed pulley 5, said oscillation damper being dimensioned for the associated cam shaft 3 and arranged to dampen or counteract rigid-body oscillation upon occurrence of the resonance frequency of the system defined in the aforegoing, with the result that the amplitudes of the angular torsion will be very small when operating at r.p. .-values where the excitation corresponds to the resonance frequency of the system, and the load on the toothed belt 6 will be considerably smaller, resulting in longer life.
• the oscillation damper 17 comprises an inertial mass 18 in the shape of an annular body 19, preferably of metal or other comparatively heavy material having a predetermined moment of inertia.
• the inertia body 19 is received in the recess 16 and is integrally connected to the driven toothed pulley 5 by way of a resilient material 20, the latter likewise being part of the oscillation damper 17.
• the resilient material 20 also is annular in shape and consists of an element 21 which preferably is made from rubber or other similar material possessing rigidity qualities making it suitable for its intended function (torsion).
• the resilient element 21 is positioned between the external envelope surface of the annular inertia body 19 and the internal, likewise annular envelope surface of the toothed rim 11.
• the resilient element 21 is positioned between the front face of the inertia body 19 and the internal face of the web portion 15 whereas in accordance with Fig. 5, the resilient element 21 is positioned between the internal envelope surface of the inertia body 19 and the external, annular envelope surface of the hub 14.
• the resilient element 21 interconnects the inertia body 19 and the toothed pulley 5, preferably by means of vulcanizing, provided that the pulley material is of a vulcanizable nature.
• glueing or other bonding methods are conceivable, for instance a press fit engagement.
• the inertia body 19 and/or the resilient element 21 may be divided into segments, the latter preferably being of equal size and being equally spaced circumferentially.
• the viscous damper 17 comprises an oscillating mass in a damping medium, such as oil or a similar viscous substance.
• One advantageous side-effect of the use of the oscillation damper 17 is the improvement of the timing of the cam shaft/shafts 5, i.e. the valves of the interna combustion engine 1 open in a more precise sequence, with resulting higher performance at the above resonance frequency of the system.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• Aviation & Aerospace Engineering (AREA)
• Valve-Gear Or Valve Arrangements (AREA)
• Devices For Conveying Motion By Means Of Endless Flexible Members (AREA)
• Pulleys (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20382417

Family Applications (1)

Country Status (5)

Cited By (7)

Citations (3)

• 1991
  • 1991-04-10 SE SE9101071A patent/SE468131B/sv not_active IP Right Cessation
• 1992
  • 1992-03-26 EP EP19920907812 patent/EP0580646A1/en not_active Withdrawn
  • 1992-03-26 JP JP4507197A patent/JPH06506515A/ja active Pending
  • 1992-03-26 DE DE92907812T patent/DE580646T1/de active Pending
  • 1992-03-26 WO PCT/SE1992/000193 patent/WO1992018754A1/en not_active Application Discontinuation

Patent Citations (3)

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