EP0380903B1 - A timing control assembly for a multi-cylinder internal combustion engine, particularly for motor vehicles - Google Patents

A timing control assembly for a multi-cylinder internal combustion engine, particularly for motor vehicles Download PDF

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Publication number
EP0380903B1
EP0380903B1 EP89830553A EP89830553A EP0380903B1 EP 0380903 B1 EP0380903 B1 EP 0380903B1 EP 89830553 A EP89830553 A EP 89830553A EP 89830553 A EP89830553 A EP 89830553A EP 0380903 B1 EP0380903 B1 EP 0380903B1
Authority
EP
European Patent Office
Prior art keywords
camshaft
integral
drive sprocket
seat
chain tensioner
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.)
Expired - Lifetime
Application number
EP89830553A
Other languages
German (de)
French (fr)
Other versions
EP0380903A1 (en
Inventor
Eppo Ricordi
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.)
Fiat Auto SpA
Original Assignee
Fiat Auto SpA
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 Fiat Auto SpA filed Critical Fiat Auto SpA
Publication of EP0380903A1 publication Critical patent/EP0380903A1/en
Application granted granted Critical
Publication of EP0380903B1 publication Critical patent/EP0380903B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • F01L1/02—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
    • 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
    • F01L1/0532—Camshafts overhead type the cams being directly in contact with the driven valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/002—Integrally formed cylinders and cylinder heads
    • 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
    • F01L2001/0535—Single overhead camshafts [SOHC]
    • 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
    • F02B2275/20—SOHC [Single overhead camshaft]

Definitions

  • the present invention relates in general to multi-cylinder internal combustion engines for motor vehicles and more particularly to a timing control assembly for such an engine.
  • the timing control assembly comprises a body within which a camshaft with respective tappets for operating the inlet and exhaust valves is mounted for rotation, and a chain of belt unit for driving the camshaft from the crankshaft of the engine, normally including a drive sprocket coupled to one end of the camshaft and an adjustable chain tensioner.
  • a camshaft with respective tappets for operating the inlet and exhaust valves is mounted for rotation
  • a chain of belt unit for driving the camshaft from the crankshaft of the engine, normally including a drive sprocket coupled to one end of the camshaft and an adjustable chain tensioner.
  • a partial solution to this problem is given in GB-A-557 700, showing a timing control assembly constituted by a preassembly unit in which the body is in one piece and has a continuous flange in a simple plane at the bottom for coupling with a complementary upper flange on the cylinder block, the body having integral bearings for the camshaft and integral seats for the tappets.
  • the object of the present invention is to provide a control assembly of the type defined above which is constituted by a reduced number of parts and which is simpler and cheaper to produce and assemble.
  • the body defines an enlarged portion between the seat for the chain tensioner and the camshaft for housing the drive sprocket of the drive unit, the housing being formed with opposing shoulders for the axial retention of the drive sprocket.
  • the drive sprocket may be fixed to the camshaft by means of a threaded coupling member which is inserted through the chain-tensioner seat during assembly, or by means of axial driving when the shaft is inserted in the body after the sprocket has been positioned between the retaining shoulders of its housing.
  • a 4-cylinder internal combustion engine for a motor car is generally indicated 1 and comprises essentially a cylinder block 2 formed integrally with the cylinders 4 and their respective combustion chambers 4a, intake ducts 5, exhaust ducts 6, seats 7 for the inlet and exhaust valves 8 and seats, not illustrated, for any spark plugs, a sump structure 3 which supports the crankshaft 9 and is fixed to the bottom of the cylinder block 2, and a timing control assembly, generally indicated 10, situated above the cylinder block 2.
  • the timing control assembly 10 is constituted by a preassembled unit constituted by a one-piece body 11 having a continuous integral flange 12 in a single plane at the bottom for joining to a corresponding continuous flange 13 formed in a single plane at the top of the cylinder block 2.
  • the body 11 is formed integrally with bearings 14 in which a camshaft 15 is mounted for rotation, and in its lower part forms integral housings 16 for tappet units 17 which are preferably hydraulic and are associated with the inlet and exhaust valves 8.
  • the body 11 has two end apertures 18, 19 coaxial with the bearings 14, of which the former serves to enable the insertion of the shaft 15 during assembly and is then closed by means of a plug 20.
  • the other end aperture 19 defines an integral seat 20 in correspondence with which is arranged an adjustable chain tensioner device 21 associated with a drive unit 22 for the camshaft 15, which is fitted to the assembly 10 before the latter is joined to the cylinder block 2 of the engine 1.
  • the drive unit 22 includes a driving sprocket 22a which is adapted to be mounted on one end of the crankshaft 9, and a driven sprocket 23 which is rotatable in an integral enlarged portion 24 of the body 11 and is keyed in the manner described below to the end of the camshaft 15, facing the aperture 19.
  • a chain or a toothed belt 25 passes over the sprockets 22a and 23 and can be adjusted by means of the chain tensioner 21.
  • the latter comprises an idle sprocket 26 carried by an arm 27 whose angular position is adjustable by means of a ring 28 which is coupled by means of frontal teeth 28a to a support 30 inserted in the seat 20 and provided with respective frontal teeth 30a.
  • the ring 28 and the support 30 are made fast to the body 11 by the tightening of a screw 29.
  • the driven sprocket 23 is rotatable between a pair of axial positioning and retaining shoulders 31 formed within the enlarged portion 24 and is keyed to the camshaft 15 according to one or other of the two variants shown respectively above and below the axis of the camshaft 15 in Figure 3.
  • the camshaft 15 has an internally-threaded hollow end part 32 into which a flanged retaining member 33 is screwed to clamp the sprocket 23 to the shaft 15.
  • assembly is achieved in the following manner: firstly, the sprocket 23 complete with the chain 25 is positioned in the housing 24 between the two positioning shoulders 31, and then the camshaft 15 is inserted in the body 11 through the aperture 18. The retaining member 33 is then introduced into the body 11 through the aperture 19 and screwed into the hollow end 32 of the shaft 15. Finally, the chain tensioner device 21 and the plug 20 are fitted.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
  • Devices For Conveying Motion By Means Of Endless Flexible Members (AREA)
  • Cylinder Crankcases Of Internal Combustion Engines (AREA)

Description

  • The present invention relates in general to multi-cylinder internal combustion engines for motor vehicles and more particularly to a timing control assembly for such an engine.
  • Conventionally, the timing control assembly comprises a body within which a camshaft with respective tappets for operating the inlet and exhaust valves is mounted for rotation, and a chain of belt unit for driving the camshaft from the crankshaft of the engine, normally including a drive sprocket coupled to one end of the camshaft and an adjustable chain tensioner. Normally such control assemblies are formed by a considerable number of components: in particular, the body of the assembly is usually constituted by various parts which are fitted together after the installation of the camshaft with its tappets and the components of the drive unit.
  • A partial solution to this problem is given in GB-A-557 700, showing a timing control assembly constituted by a preassembly unit in which the body is in one piece and has a continuous flange in a simple plane at the bottom for coupling with a complementary upper flange on the cylinder block, the body having integral bearings for the camshaft and integral seats for the tappets.
  • The object of the present invention is to provide a control assembly of the type defined above which is constituted by a reduced number of parts and which is simpler and cheaper to produce and assemble.
  • According to the invention, this object is achieved by virtue of the features set forth in the characterising portion of Claim 1.
  • Preferably, the body defines an enlarged portion between the seat for the chain tensioner and the camshaft for housing the drive sprocket of the drive unit, the housing being formed with opposing shoulders for the axial retention of the drive sprocket.
  • The drive sprocket may be fixed to the camshaft by means of a threaded coupling member which is inserted through the chain-tensioner seat during assembly, or by means of axial driving when the shaft is inserted in the body after the sprocket has been positioned between the retaining shoulders of its housing.
  • Further characteristics and advantages of the present invention will become clear from the detailed description which follows with reference to the appended drawings, provided by way of non-limiting example, in which:
    • Figure 1 is a schematic cross-section of an internal combustion engine provided with a timing control assembly according to the invention,
    • Figure 2 is a partial longitudinal section taken on the line II-II of Figure 1, and
    • Figure 3 is a section of the detail indicated by the arrow III in Figure 2, on an enlarged scale.
  • With reference initially to Figure 1, a 4-cylinder internal combustion engine for a motor car is generally indicated 1 and comprises essentially a cylinder block 2 formed integrally with the cylinders 4 and their respective combustion chambers 4a, intake ducts 5, exhaust ducts 6, seats 7 for the inlet and exhaust valves 8 and seats, not illustrated, for any spark plugs, a sump structure 3 which supports the crankshaft 9 and is fixed to the bottom of the cylinder block 2, and a timing control assembly, generally indicated 10, situated above the cylinder block 2.
  • With reference in greater detail to Figure 2, the timing control assembly 10 is constituted by a preassembled unit constituted by a one-piece body 11 having a continuous integral flange 12 in a single plane at the bottom for joining to a corresponding continuous flange 13 formed in a single plane at the top of the cylinder block 2.
  • The body 11 is formed integrally with bearings 14 in which a camshaft 15 is mounted for rotation, and in its lower part forms integral housings 16 for tappet units 17 which are preferably hydraulic and are associated with the inlet and exhaust valves 8.
  • The body 11 has two end apertures 18, 19 coaxial with the bearings 14, of which the former serves to enable the insertion of the shaft 15 during assembly and is then closed by means of a plug 20.
  • The other end aperture 19 defines an integral seat 20 in correspondence with which is arranged an adjustable chain tensioner device 21 associated with a drive unit 22 for the camshaft 15, which is fitted to the assembly 10 before the latter is joined to the cylinder block 2 of the engine 1.
  • As shown in greater detail in Figures 2 and 3, the drive unit 22 includes a driving sprocket 22a which is adapted to be mounted on one end of the crankshaft 9, and a driven sprocket 23 which is rotatable in an integral enlarged portion 24 of the body 11 and is keyed in the manner described below to the end of the camshaft 15, facing the aperture 19.
  • A chain or a toothed belt 25 passes over the sprockets 22a and 23 and can be adjusted by means of the chain tensioner 21. The latter comprises an idle sprocket 26 carried by an arm 27 whose angular position is adjustable by means of a ring 28 which is coupled by means of frontal teeth 28a to a support 30 inserted in the seat 20 and provided with respective frontal teeth 30a. When the adjustment has been carried out, the ring 28 and the support 30 are made fast to the body 11 by the tightening of a screw 29.
  • The driven sprocket 23 is rotatable between a pair of axial positioning and retaining shoulders 31 formed within the enlarged portion 24 and is keyed to the camshaft 15 according to one or other of the two variants shown respectively above and below the axis of the camshaft 15 in Figure 3. According to the first variant, shown in the upper part of Figure 3, the camshaft 15 has an internally-threaded hollow end part 32 into which a flanged retaining member 33 is screwed to clamp the sprocket 23 to the shaft 15. In this case, assembly is achieved in the following manner: firstly, the sprocket 23 complete with the chain 25 is positioned in the housing 24 between the two positioning shoulders 31, and then the camshaft 15 is inserted in the body 11 through the aperture 18. The retaining member 33 is then introduced into the body 11 through the aperture 19 and screwed into the hollow end 32 of the shaft 15. Finally, the chain tensioner device 21 and the plug 20 are fitted.
  • In the case of the second variant, shown in the lower part of Figure 3, the end of the shaft 15 is simply driven into the sprocket 23, after the latter has been positioned in the housing 24 between the two positioning and retaining shoulders 31.

Claims (4)

  1. A timing control assembly (10) for a multi-cylinder internal combustion engine having a cylinder block and a crankshaft, comprising a body (11) containing a camshaft (15) and its respective tappets (17), and a chain or belt unit (25) for driving the camshaft from the crankshaft of the engine, including a drive sprocket (23) coupled to one end of the camshaft and an adjustable chain tensioner (21), the assembly being constituted by a preassembled unit (10) in which the body (11) is in one piece and has a continuous flange (12) in a single plane at the bottom for coupling with a complementary upper flange (13) on the cylinder block (2), the body (11) having integral bearings (14) for the camshaft (15) and integral seats (16) for the tappets (17), characterised in that the body axially extends on both sides of the camshaft ends and has two end apertures (18, 19) coaxial with the camshaft bearings (14), an end aperture (19) defining an integral end seat (20) in which the chain tensioner (21) is fitted, and the other end aperture (18) serves for the insertion of the camshaft (15) into the body (11) at the opposite end from the integral end seat (20).
  2. An assembly according to Claim 1, characterised in that the body (11) has an integral enlarged portion (24) between the seat (20) for the chain tensioner (21) and the camshaft (15) for housing the drive sprocket (23), the housing (24) being provided with opposed shoulder (31) for the axial positioning and retention of the drive sprocket (23).
  3. An assembly according to Claim 2, characterised in that the drive sprocket (23) is fixed to the camshaft (15) by means of a threaded coupling member (33) which is inserted through the seat (20) of the chain tensioner (21) during assembly and is screwed into a corresponding internally-threaded hollow end (32) of the camshaft (15).
  4. An assembly according to Claim 2, characterised in that the drive sprocket (23) is fixed to the camshaft (15) by axial driving.
EP89830553A 1988-12-30 1989-12-19 A timing control assembly for a multi-cylinder internal combustion engine, particularly for motor vehicles Expired - Lifetime EP0380903B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT68178/88A IT1224052B (en) 1988-12-30 1988-12-30 DISTRIBUTION CONTROL UNIT FOR A MULTI-CYLINDER INTERNAL COMBUSTION ENGINE PARTICULARLY FOR VEHICLES
IT6817888 1988-12-30

Publications (2)

Publication Number Publication Date
EP0380903A1 EP0380903A1 (en) 1990-08-08
EP0380903B1 true EP0380903B1 (en) 1993-04-14

Family

ID=11308353

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89830553A Expired - Lifetime EP0380903B1 (en) 1988-12-30 1989-12-19 A timing control assembly for a multi-cylinder internal combustion engine, particularly for motor vehicles

Country Status (5)

Country Link
EP (1) EP0380903B1 (en)
BR (1) BR8906871A (en)
DE (1) DE68906014T2 (en)
ES (1) ES2039940T3 (en)
IT (1) IT1224052B (en)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB557700A (en) * 1942-05-22 1943-12-01 Harold Raymond Morgan A housing for the valve-gear of an internal combustion engine
FR1515767A (en) * 1966-10-20 1968-03-01 Device automatically correcting the distribution in four-stroke engines
DE3406100A1 (en) * 1984-02-18 1985-08-22 Willi 7171 Michelfeld Roth SPEED-ADJUSTABLE ADJUSTMENT OF VALVE CONTROL TIMES IN COMBUSTION ENGINES

Also Published As

Publication number Publication date
DE68906014D1 (en) 1993-05-19
IT1224052B (en) 1990-09-26
DE68906014T2 (en) 1993-07-22
ES2039940T3 (en) 1993-10-01
IT8868178A0 (en) 1988-12-30
EP0380903A1 (en) 1990-08-08
BR8906871A (en) 1990-09-25

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