US20040206323A1 - Camshaft drive for engine - Google Patents

Camshaft drive for engine Download PDF

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Publication number
US20040206323A1
US20040206323A1 US10/776,852 US77685204A US2004206323A1 US 20040206323 A1 US20040206323 A1 US 20040206323A1 US 77685204 A US77685204 A US 77685204A US 2004206323 A1 US2004206323 A1 US 2004206323A1
Authority
US
United States
Prior art keywords
sprocket
chain
camshaft
engine
crankshaft
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.)
Abandoned
Application number
US10/776,852
Other languages
English (en)
Inventor
Tadashi Shintani
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.)
Tsubakimoto Chain Co
Original Assignee
Tsubakimoto Chain Co
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 Tsubakimoto Chain Co filed Critical Tsubakimoto Chain Co
Assigned to TSUBAKIMOTO CHAIN CO. reassignment TSUBAKIMOTO CHAIN CO. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: SHINTANI, TADASHI
Publication of US20040206323A1 publication Critical patent/US20040206323A1/en
Abandoned legal-status Critical Current

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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
    • F16H—GEARING
    • F16H7/00—Gearings for conveying rotary motion by endless flexible members
    • F16H7/06—Gearings for conveying rotary motion by endless flexible members with chains
    • 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
    • F01L1/022—Chain 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]

Definitions

  • This invention relates to a timing transmission mechanism for transmitting power from a crankshaft to a camshaft in an internal combustion engine, and more specifically to a chain drive for transmitting power from a crankshaft to camshafts in a four-cycle engine for an automobile.
  • a typical conventional camshaft drive for a dual-cam engine includes an idler sprocket 12 disposed between a crank sprocket 16 and the camshaft sprockets 18 .
  • the camshaft sprockets are driven by a first timing chain 21 wrapped around the crank sprocket 16 and the idler sprocket 12 , and a second timing chain 22 wrapped around the idler sprocket 12 and the camshaft sprockets 18 .
  • the chains 21 and 22 differ from each other in that the pitch of first chain 21 is less than the pitch of the second timing chain 22 .
  • an object of this invention is to address the above-mentioned problems, and to provide a camshaft drive for the timing transmission of an engine, which is capable of withstanding high loads, but which enables the engine size to be reduced and also reduces production cost.
  • the engine camshaft drive in accordance with the invention comprises a crankshaft sprocket; large and small camshaft sprockets in coaxial relationship with each other, and fixedly connected to each other for rotation together about a first axis; a third camshaft sprocket spaced laterally from the large and small camshaft sprockets, and rotatable about a second axis parallel to the first axis; a driving chain wrapped around the crankshaft sprocket and the large camshaft sprocket, for transmitting rotational power from the crankshaft sprocket to the large camshaft sprocket; and a driven chain wrapped around the small camshaft sprocket and the third camshaft sprocket, for transmitting rotational power from the small camshaft sprocket to the third camshaft sprocket.
  • the strength of the driven chain is less than the strength of the driving chain.
  • the driving chain and the driven chain may be roller chains, or silent chains or the like.
  • silent chains When silent chains are used, the camshaft drive produces less noise than is produced in the case where roller chains are used.
  • the strengths of the driving and driven chains in the camshaft drive according to the invention can be determined by the appropriate choice of chain parameters, including the chain structure, and the chain material.
  • the appropriate chain structure can be chosen by taking into account factors such as the outer diameters of the chain connecting pins, and the thicknesses of the link plates.
  • rotating power is transmitted from the crankshaft sprocket to the larger camshaft sprocket through the driving chain.
  • the camshaft sprocket rotates more slowly than the crankshaft sprocket.
  • Rotating power, transmitted from the smaller camshaft sprocket, is transmitted to the other camshaft sprocket through the driven chain so that both camshafts rotate together, ordinarily at the same rotational speed.
  • the driving chain transmits power under a high load.
  • the smaller of the coaxial larger and smaller camshaft sprockets has the same diameter as the other camshaft sprocket, the driven chain transmits power without incurring the high load conditions incurred in the driving chain.
  • FIG. 1 is a schematic elevational view showing the configuration of a camshaft drive in accordance with a first embodiment of the invention
  • FIG. 2 is a schematic elevational view showing the configuration of a camshaft drive in accordance with a second embodiment of the invention.
  • FIG. 3 a schematic elevational view showing the configuration of a conventional camshaft drive.
  • camshaft drive 100 which is used in a four cycle engine, comprises a roller chain 130 , wrapped around a crankshaft sprocket 110 and a larger camshaft sprocket 120 .
  • Roller chain 130 is used as a driving chain, directly transmitting rotational power from the crankshaft to one of the two camshafts (not shown).
  • the drive 100 also comprises a second roller chain 160 wrapped around a smaller sprocket 140 , coaxial with sprocket 120 , and a second smaller camshaft sprocket 150 on the other of the two camshafts.
  • Sprocket 140 is fixed to sprocket 120 , so that both sprockets rotate together.
  • chain 160 serves as a driven chain
  • chain 130 serves as a driving chain.
  • the outer diameters of the pins which connect the links together, and/or the thicknesses of the link plates, are such that the strength of the driven chain 160 is less than the strength of the driving chain 130 .
  • Other chain component parameters may also affect the strengths of the chains.
  • driving chain 130 and the driven chain 160 in FIG. 1 are roller chains, silent chains can be used as an alternative in order to reduce transmission noises.
  • the larger camshaft sprocket 120 has twice as many teeth as crankshaft sprocket 110 , and consequently the camshaft sprockets 120 and 140 rotate at one-half the rotational speed of the crankshaft sprocket 110 .
  • the second smaller camshaft sprocket 150 which has the same number of teeth as sprocket 140 , also rotates at one-half the rotational speed of the crankshaft sprocket.
  • crankshaft sprocket 110 the rotational power produced at the crankshaft is transmitted from crankshaft sprocket 110 to the larger camshaft sprocket 120 through the driving chain 130 .
  • Sprocket 120 , and the smaller sprocket 140 which is coaxial with sprocket 120 , both rotate at one-half the rotational speed of the crankshaft sprocket, and the rotating power is transmitted from smaller sprocket 140 to the second, smaller, camshaft sprocket 150 through driven chain 160 , so that both camshafts rotate at the same rate, for operation of the intake and exhaust valves of the engine.
  • the driven chain 160 does not need to have the load capacity of the driving chain 130 .
  • the chains can be matched to the torques that they need to transmit without any disadvantages.
  • the engine production cost can be reduced by utilizing a less expensive chain as the driven chain, and the engine size, and its product cost, can also be reduced as a result of the omission of the conventional intermediate shaft.
  • a camshaft drive 200 also for a four cycle engine, comprises a roller chain 230 , wrapped around a crankshaft sprocket 210 and a larger camshaft sprocket 220 .
  • Roller chain 230 is used as a driving chain, directly transmitting rotational power from the crankshaft to one of the two camshafts (not shown).
  • the drive 200 also comprises a second roller chain 260 wrapped around a smaller sprocket 240 , coaxial with sprocket 220 , and a second smaller camshaft sprocket 250 on the other of the two camshafts.
  • Sprocket 240 is fixed to sprocket 220 , so that both sprockets rotate together.
  • chain 260 serves as a driven chain
  • chain 230 serves as a driving chain.
  • the outer diameters of the pins which connect the links together, and/or the thicknesses of the link plates, are such that the strength of the driven chain 260 is less than the strength of the driving chain 230 .
  • the chain pitch P2 of the driven chain 260 is also less than the chain pitch P1 of the driving chain 230 .
  • the larger camshaft sprocket 220 has twice as many teeth as crankshaft sprocket 210 , and consequently the camshaft sprockets 220 and 240 rotate at one-half the rotational speed of the crankshaft sprocket 210 .
  • the second smaller camshaft sprocket 250 which has the same number of teeth as sprocket 240 , also rotates at one-half the rotational speed of the crankshaft sprocket.
  • crankshaft sprocket 210 In the operation of the camshaft drive 200 , the rotational power produced at the crankshaft is transmitted from crankshaft sprocket 210 to the larger camshaft sprocket 220 through the driving chain 230 .
  • Sprocket 220 , and the smaller sprocket 240 which is coaxial with sprocket 220 , both rotate at one-half the rotational speed of the crankshaft sprocket, and the rotating power is transmitted from smaller sprocket 240 to the second, smaller, camshaft sprocket 250 through driven chain 260 , so that both camshafts rotate at the same rate, for operation of the intake and exhaust valves of the engine.
  • the driven chain 260 does not need to have the load capacity of the driving chain 230 .
  • the chains can be matched to the torques that they need to transmit without any disadvantages.
  • the engine production cost can be reduced by utilizing a less expensive chain as the driven chain, and the engine size and its product cost can also be reduced as a result of removal of the conventional intermediate shaft.
  • An additional significant improvement afforded by the embodiment of FIG. 2 is that, since the chain pitch P2 of the driven chain 260 is less than the chain pitch P1 of the driving chain 230 , the driven chain and the smaller camshaft sprockets 240 and 250 can be reduced in size.
  • a first one of the camshafts is driven directly through a drive chain by the crankshaft, and the other camshaft is driven through a driven chain, which does not need to be as strong as the driving chain.
  • the chains can be matched to the torques incurred in the respective parts of the power transmission without incurring disadvantages. As a result, a cost reduction can be realized.
  • the intermediate shaft, used in a conventional timing transmission can be eliminated, the size of the engine can be reduced.
  • the pitch of the driven chain can be made smaller than the pitch of the driving chain. If this is done, the sizes of the driven chain and the camshaft sprockets can also be reduced, whereby further reduction in the overall size of the engine can be realized.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
  • Devices For Conveying Motion By Means Of Endless Flexible Members (AREA)
US10/776,852 2003-04-17 2004-02-11 Camshaft drive for engine Abandoned US20040206323A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2003-113071 2003-04-17
JP2003113071A JP2004316573A (ja) 2003-04-17 2003-04-17 エンジン用カム軸駆動装置

Publications (1)

Publication Number Publication Date
US20040206323A1 true US20040206323A1 (en) 2004-10-21

Family

ID=32906065

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/776,852 Abandoned US20040206323A1 (en) 2003-04-17 2004-02-11 Camshaft drive for engine

Country Status (4)

Country Link
US (1) US20040206323A1 (de)
EP (1) EP1469167B1 (de)
JP (1) JP2004316573A (de)
DE (1) DE602004000163T2 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130139773A1 (en) * 2011-12-06 2013-06-06 Ford Global Technologies, Llc Engine drive system
GB2497561A (en) * 2011-12-14 2013-06-19 Perkins Engines Co Ltd Belt drive having subtractive belt tension force vectors
US8726868B2 (en) 2012-01-16 2014-05-20 Ford Global Technologies, Llc Engine drive system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2522850A (en) * 2014-02-05 2015-08-12 Gm Global Tech Operations Inc Timing drive of an internal combustion engine

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3969949A (en) * 1972-05-01 1976-07-20 Tsubakimoto Chain Co. Fillerless welded chain
US5058458A (en) * 1989-04-28 1991-10-22 Tsubakimoto Chain Co. Camshaft driving mechanism
US5216984A (en) * 1991-07-26 1993-06-08 Nissan Motor Co., Ltd. V-type internal combustion engine with improved water pump driving arrangement
US5470282A (en) * 1992-05-19 1995-11-28 Borg-Warner Automotive, Inc. Phased chain assemblies having links with a single toe
US6250266B1 (en) * 1998-12-25 2001-06-26 Yamaha Hatsudoki Kabushiki Kaisha Variable valve timing mechanism for engine
US20020134336A1 (en) * 2000-01-05 2002-09-26 Markus Duesmann Chain drive for driving two parallel shafts located close to each other

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1308453B1 (it) * 1999-04-23 2001-12-17 Iveco Fiat Dispositivo di trasmissione a catena per il comando delladistribuzione di un motore endotermico a due alberi a camme in testa

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3969949A (en) * 1972-05-01 1976-07-20 Tsubakimoto Chain Co. Fillerless welded chain
US5058458A (en) * 1989-04-28 1991-10-22 Tsubakimoto Chain Co. Camshaft driving mechanism
US5216984A (en) * 1991-07-26 1993-06-08 Nissan Motor Co., Ltd. V-type internal combustion engine with improved water pump driving arrangement
US5470282A (en) * 1992-05-19 1995-11-28 Borg-Warner Automotive, Inc. Phased chain assemblies having links with a single toe
US6250266B1 (en) * 1998-12-25 2001-06-26 Yamaha Hatsudoki Kabushiki Kaisha Variable valve timing mechanism for engine
US6367435B2 (en) * 1998-12-25 2002-04-09 Yamaha Hatsudoki Kabushiki Kaisha Variable valve timing mechanism for engine
US20020134336A1 (en) * 2000-01-05 2002-09-26 Markus Duesmann Chain drive for driving two parallel shafts located close to each other

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130139773A1 (en) * 2011-12-06 2013-06-06 Ford Global Technologies, Llc Engine drive system
US8701611B2 (en) * 2011-12-06 2014-04-22 Ford Global Technologies, Llc Engine drive system
GB2497561A (en) * 2011-12-14 2013-06-19 Perkins Engines Co Ltd Belt drive having subtractive belt tension force vectors
GB2497561B (en) * 2011-12-14 2014-01-29 Perkins Engines Co Ltd Belt drives
US8726868B2 (en) 2012-01-16 2014-05-20 Ford Global Technologies, Llc Engine drive system

Also Published As

Publication number Publication date
DE602004000163T2 (de) 2006-08-03
DE602004000163D1 (de) 2005-12-08
JP2004316573A (ja) 2004-11-11
EP1469167B1 (de) 2005-11-02
EP1469167A1 (de) 2004-10-20

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Legal Events

Date Code Title Description
AS Assignment

Owner name: TSUBAKIMOTO CHAIN CO., JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SHINTANI, TADASHI;REEL/FRAME:015330/0524

Effective date: 20040209

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION