GB2140079A - Camshaft drive of an internal combustion engine - Google Patents

Camshaft drive of an internal combustion engine Download PDF

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Publication number
GB2140079A
GB2140079A GB08406975A GB8406975A GB2140079A GB 2140079 A GB2140079 A GB 2140079A GB 08406975 A GB08406975 A GB 08406975A GB 8406975 A GB8406975 A GB 8406975A GB 2140079 A GB2140079 A GB 2140079A
Authority
GB
United Kingdom
Prior art keywords
gearwheel
camshaft
crankshaft
gear
housing
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.)
Granted
Application number
GB08406975A
Other versions
GB8406975D0 (en
GB2140079B (en
Inventor
Heinz Dorsch
Michael Beer
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.)
Dr Ing HCF Porsche AG
Original Assignee
Dr Ing HCF Porsche AG
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 Dr Ing HCF Porsche AG filed Critical Dr Ing HCF Porsche AG
Publication of GB8406975D0 publication Critical patent/GB8406975D0/en
Publication of GB2140079A publication Critical patent/GB2140079A/en
Application granted granted Critical
Publication of GB2140079B publication Critical patent/GB2140079B/en
Expired 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
    • F01L1/026—Gear 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

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Valve-Gear Or Valve Arrangements (AREA)
  • Gear Transmission (AREA)

Abstract

In order to compensate for the thermal induced increase in the distance of the camshaft axis (11) with respect to the crankshaft axis (10) and to hold the torsional flank play at the engaging gear teeth constant, a gearwheel (15) engaging with the camshaft gearwheel (12) has its axis (20) arranged at or adjacent a line (21) passing through the axis (11) of the camshaft gearwheel (12), said line (21) extending approximately perpendicularly to a line (9) extending between the axis (11, 10) of the camshaft gearwheel (12) and the crankshaft gearwheel (2). The deviation from the perpendicularly may be up to about 30 DEG . <IMAGE>

Description

SPECIFICATION Camshaft drive of an internal combustion engine The invention relates to a camshaft drive of an internal combustion engine of the type in which a plurality of gearwheels transmit the drive from the crankshaft to the camshaft, the gearwheels being arranged partly in the crankshaft housing and partly in a gear housing connected to the crankshaft housing.
During warm up of an internal combustion engine, the temperature of the cylinders and the cylinder head increases faster and reaches a higher level than the temperature of the gear housing and camshaft driving gear drive arrangement mounted at the outside of the engine crankshaft housing. Consequently, the distance between the crankshaft and the camshaft increases faster and is all together larger than the entire temperature pendant length extension of the gear drive arrangement. With the use of a customary arrangement of gearwheels, as disclosed in the German published unexamined application (DE-OS) 25 02 033, there will thereby be a marked increase in the torsional backlash between teeth of the gearwheel meshing with the teeth of the camshaft gearwheel, with a resultant increase in noise and damage to the gear teeth profile.These difficulties increase if the gearwheels are constructed of a material with a smaller thermal elongation coefficient than the material of the cylinder head and the crankshaft housing.
It is therefore an objection of the invention to provide a compensation of these different thermal expansions and therewith avoid an increase in the torsional backlash of the gear teeth during warm up of the combustion engine.
Optimal conditions result when the axis of the intermediate gear is disposed on a line exactly perpendicular to the line passing through the axes of the crankshaft and camshaft gearwheels. But deviation from the perpendicular up to about 30 still lead to a satisfactory resuit.
In the accompanying drawings: Figure 1 is a front view of a gear drive arrangement according to the present invention, and Figure 2 is a plan view of Fig. 1.
Referring now to the embodiment shown in the drawings, a crankshaft gearwheel 2 is fixedly connected to a crankshaft 1 and is rotatably supported by bearings 3 and 4 of a crankshaft housing 5. The crankshaft gearwheel 2 drives a larger gearwheel 6 disposed therebelow and the shaft of the gearwheel 6 is also supported in the crank housing 5 and extends parallel to the crankshaft 1. The axis 7 of the gearwheel 6 is disposed on a line 8 which extends perpendicular to a line 9 extending between the axis 10 of the crankshaft gear 2 and the axis 11 of a camshaft gear 1 2.
The camshaft gear 12 is fixedly connected to a camshaft 1 3 which is rotatably supported in a lightweight metal cylinder head 14.
A gearwheel 1 5 drivingly meshing with the camshaft gearwheel 1 2 is rotatably supported by bearings 16, 1 7 of a gear housing 1 8 which is connected by a flange 1 9 to the crank housing 5. The axis 20 of the gearwheel 1 5 is disposed at a small distance S from a line 21 which is perpendicular to line 9 and forms, with the illustrated selected gearwheel sizes, an angle of approximately 87 to line 9 (angle between line 9 and a line passing through axes 11 and 20).The gearwheels 1 5 drivingly engages a gearwheel 22 that is likewise rotatably supported by the gear housing 18 and drives a gearwheel 24 via a gearwheel 23 rotatably supported by the crank housing 5, the gearwheel 24 being mounted on the same shaft as the gearwheel 6 engaging with the crankshaft gearwheel 2.
With a six cylinder boxer type engine with which the above described camshaft drive can be used, upon a warm up of the engine, the distance of the camshaft relative to the axis of the gearwheel 1 5 increases in about 40 seconds approximately 1 millimeter (1 mm) in the direction of the line 9. With the present invention it is possible to compensate for this difference in distance through a curve shaped roll off movement of the camshaft gearwheel 12 around the axis 20 of the gearwheel 1 5 so that the torsional flank "play" at the engaging teeth is not enlarged. At best, one achieves this goal best by arranging that the axes 10, 11, 20, 7 of the crankshaft gearwheel 2, the camshaft gearwheel 12, the gearwheel 15, and the gearwheel 6 respectively, form the corner point of a rectangle 25.
1. A driving gear arrangement of a camshaft rotatably supported in the cylinder head of an internal combustion engine comprising a plurality of gearwheel connecting the engine crankshaft with the camshaft, said gearwheels being arranged partly in the crankshaft housing and partly in a gear housing connected to the crankshaft housing, wherein the axis of an intermediate gearwheel engaged with a camshaft gearwheel is disposed at or adjacent a line passing through the axis of the camshaft wheel, which axis is approximately perpendicular to a line connecting the axes of the crankshaft and camshaft gearwheels.
2. A driving gear arrangement according to claim 1, wherein the axes of the crankshaft gearwheel, the camshaft gearwheel, the intermediate gearwheel and a further intermediate gearwheel engaged with the crankshaft gearwheel are located approximately at the corners of a rectangle.
3. A driving gear arrangement according to claim 1 or 2, wherein the camshaft gear
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Camshaft drive of an internal combustion engine The invention relates to a camshaft drive of an internal combustion engine of the type in which a plurality of gearwheels transmit the drive from the crankshaft to the camshaft, the gearwheels being arranged partly in the crankshaft housing and partly in a gear housing connected to the crankshaft housing. During warm up of an internal combustion engine, the temperature of the cylinders and the cylinder head increases faster and reaches a higher level than the temperature of the gear housing and camshaft driving gear drive arrangement mounted at the outside of the engine crankshaft housing. Consequently, the distance between the crankshaft and the camshaft increases faster and is all together larger than the entire temperature pendant length extension of the gear drive arrangement. With the use of a customary arrangement of gearwheels, as disclosed in the German published unexamined application (DE-OS) 25 02 033, there will thereby be a marked increase in the torsional backlash between teeth of the gearwheel meshing with the teeth of the camshaft gearwheel, with a resultant increase in noise and damage to the gear teeth profile.These difficulties increase if the gearwheels are constructed of a material with a smaller thermal elongation coefficient than the material of the cylinder head and the crankshaft housing. It is therefore an objection of the invention to provide a compensation of these different thermal expansions and therewith avoid an increase in the torsional backlash of the gear teeth during warm up of the combustion engine. Optimal conditions result when the axis of the intermediate gear is disposed on a line exactly perpendicular to the line passing through the axes of the crankshaft and camshaft gearwheels. But deviation from the perpendicular up to about 30 still lead to a satisfactory resuit. In the accompanying drawings: Figure 1 is a front view of a gear drive arrangement according to the present invention, and Figure 2 is a plan view of Fig. 1. Referring now to the embodiment shown in the drawings, a crankshaft gearwheel 2 is fixedly connected to a crankshaft 1 and is rotatably supported by bearings 3 and 4 of a crankshaft housing 5. The crankshaft gearwheel 2 drives a larger gearwheel 6 disposed therebelow and the shaft of the gearwheel 6 is also supported in the crank housing 5 and extends parallel to the crankshaft 1. The axis 7 of the gearwheel 6 is disposed on a line 8 which extends perpendicular to a line 9 extending between the axis 10 of the crankshaft gear 2 and the axis 11 of a camshaft gear 1 2. The camshaft gear 12 is fixedly connected to a camshaft 1 3 which is rotatably supported in a lightweight metal cylinder head 14. A gearwheel 1 5 drivingly meshing with the camshaft gearwheel 1 2 is rotatably supported by bearings 16, 1 7 of a gear housing 1 8 which is connected by a flange 1 9 to the crank housing 5. The axis 20 of the gearwheel 1 5 is disposed at a small distance S from a line 21 which is perpendicular to line 9 and forms, with the illustrated selected gearwheel sizes, an angle of approximately 87 to line 9 (angle between line 9 and a line passing through axes 11 and 20).The gearwheels 1 5 drivingly engages a gearwheel 22 that is likewise rotatably supported by the gear housing 18 and drives a gearwheel 24 via a gearwheel 23 rotatably supported by the crank housing 5, the gearwheel 24 being mounted on the same shaft as the gearwheel 6 engaging with the crankshaft gearwheel 2. With a six cylinder boxer type engine with which the above described camshaft drive can be used, upon a warm up of the engine, the distance of the camshaft relative to the axis of the gearwheel 1 5 increases in about 40 seconds approximately 1 millimeter (1 mm) in the direction of the line 9. With the present invention it is possible to compensate for this difference in distance through a curve shaped roll off movement of the camshaft gearwheel 12 around the axis 20 of the gearwheel 1 5 so that the torsional flank "play" at the engaging teeth is not enlarged. At best, one achieves this goal best by arranging that the axes 10, 11, 20, 7 of the crankshaft gearwheel 2, the camshaft gearwheel 12, the gearwheel 15, and the gearwheel 6 respectively, form the corner point of a rectangle 25. CLAIMS
1. A driving gear arrangement of a camshaft rotatably supported in the cylinder head of an internal combustion engine comprising a plurality of gearwheel connecting the engine crankshaft with the camshaft, said gearwheels being arranged partly in the crankshaft housing and partly in a gear housing connected to the crankshaft housing, wherein the axis of an intermediate gearwheel engaged with a camshaft gearwheel is disposed at or adjacent a line passing through the axis of the camshaft wheel, which axis is approximately perpendicular to a line connecting the axes of the crankshaft and camshaft gearwheels.
2. A driving gear arrangement according to claim 1, wherein the axes of the crankshaft gearwheel, the camshaft gearwheel, the intermediate gearwheel and a further intermediate gearwheel engaged with the crankshaft gearwheel are located approximately at the corners of a rectangle.
3. A driving gear arrangement according to claim 1 or 2, wherein the camshaft gear wheel 1 2 is fastened to the camshaft 1 3 and is surrounded by the gear housing 1 8.
4. A driving gear arrangement according to any of claims 1 to 3, wherein the gearwheels are formed of a steel alloy and the crankshaft housing, the cylinder head and the gear housing are formed of an aluminum alloy.
5. A driving gear arrangement substantially as described with reference to, and as illustrated in, the accompanying drawings.
GB08406975A 1983-03-16 1984-03-16 Camshaft drive of an internal combustion engine Expired GB2140079B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE3309376A DE3309376C1 (en) 1983-03-16 1983-03-16 Camshaft drive of an internal combustion engine

Publications (3)

Publication Number Publication Date
GB8406975D0 GB8406975D0 (en) 1984-04-18
GB2140079A true GB2140079A (en) 1984-11-21
GB2140079B GB2140079B (en) 1986-08-13

Family

ID=6193618

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08406975A Expired GB2140079B (en) 1983-03-16 1984-03-16 Camshaft drive of an internal combustion engine

Country Status (4)

Country Link
DE (1) DE3309376C1 (en)
FR (1) FR2542806B1 (en)
GB (1) GB2140079B (en)
IT (1) IT1175446B (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1002945A2 (en) * 1998-11-20 2000-05-24 Volkswagen Aktiengesellschaft Externally toothed wheel drive for a cam shaft of an internal combustion engine
EP1048824A3 (en) * 1999-04-29 2001-12-19 Volkswagen Aktiengesellschaft Combustion engine with frontal gear drive

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4915070A (en) * 1988-03-31 1990-04-10 Yamaha Hatsudoki Kabushiki Kaisha Engine unit for motor vehicle
DE102008034725A1 (en) * 2008-07-25 2010-01-28 Man Diesel Se Internal combustion engine i.e. ship diesel engine, has control drive with housing, which is designed as separate component with respect to cylinder crank housing and is divided into two sections such as base plate and cover

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB223716A (en) * 1923-09-28 1924-10-30 William Beardmore Improvements in or relating to internal combustion engines
GB427808A (en) * 1933-10-31 1935-04-30 Bristol Aeroplane Co Ltd Improvements in or relating to valve gear for multi-cylinder internal-combustion engines
US3502059A (en) * 1968-03-20 1970-03-24 Gen Motors Corp Adjustable gear train
GB2049044A (en) * 1979-04-28 1980-12-17 Maschf Augsburg Nuernberg Ag Timing Gear Housing of an Internal Combustion Engine

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CS169211B1 (en) * 1974-01-24 1976-07-29

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB223716A (en) * 1923-09-28 1924-10-30 William Beardmore Improvements in or relating to internal combustion engines
GB427808A (en) * 1933-10-31 1935-04-30 Bristol Aeroplane Co Ltd Improvements in or relating to valve gear for multi-cylinder internal-combustion engines
US3502059A (en) * 1968-03-20 1970-03-24 Gen Motors Corp Adjustable gear train
GB2049044A (en) * 1979-04-28 1980-12-17 Maschf Augsburg Nuernberg Ag Timing Gear Housing of an Internal Combustion Engine

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1002945A2 (en) * 1998-11-20 2000-05-24 Volkswagen Aktiengesellschaft Externally toothed wheel drive for a cam shaft of an internal combustion engine
EP1002945A3 (en) * 1998-11-20 2001-04-18 Volkswagen Aktiengesellschaft Externally toothed wheel drive for a cam shaft of an internal combustion engine
EP1048824A3 (en) * 1999-04-29 2001-12-19 Volkswagen Aktiengesellschaft Combustion engine with frontal gear drive

Also Published As

Publication number Publication date
IT8419962A0 (en) 1984-03-09
FR2542806B1 (en) 1986-10-31
IT1175446B (en) 1987-07-01
DE3309376C1 (en) 1984-11-08
FR2542806A1 (en) 1984-09-21
GB8406975D0 (en) 1984-04-18
GB2140079B (en) 1986-08-13

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PCNP Patent ceased through non-payment of renewal fee