GB2085999A - Valve gear for internal combustion engines - Google Patents
Valve gear for internal combustion engines Download PDFInfo
- Publication number
- GB2085999A GB2085999A GB8127570A GB8127570A GB2085999A GB 2085999 A GB2085999 A GB 2085999A GB 8127570 A GB8127570 A GB 8127570A GB 8127570 A GB8127570 A GB 8127570A GB 2085999 A GB2085999 A GB 2085999A
- Authority
- GB
- United Kingdom
- Prior art keywords
- teeth
- belt
- toothed
- tooth
- internal combustion
- 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.)
- Withdrawn
Links
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
- F16H7/02—Gearings for conveying rotary motion by endless flexible members with belts; with V-belts
- F16H7/023—Gearings for conveying rotary motion by endless flexible members with belts; with V-belts with belts having a toothed contact surface or regularly spaced bosses or hollows for slipless or nearly slipless meshing with complementary profiled contact surface of a pulley
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Pulleys (AREA)
- Devices For Conveying Motion By Means Of Endless Flexible Members (AREA)
Abstract
Valve gear for internal combustion engines comprises toothed wheels (2) fixed to the engine crankshaft and camshaft, and a toothed belt (1) effecting driving connection therebetween. The relative dimensions of the teeth on the wheels and the teeth (4) on the belt are so chosen that backlash (X) between the teeth on the belt in the recess (5) between adjacent teeth on the wheels is minimised e.g. less than 0.0125 inches (0.3 mm). <IMAGE>
Description
SPECIFICATION
Valve gear for an internal combustion engine
This invention relates to a valve gear for internal combustion engines.
It is known, for example from German Patent
Specification DE-AS 29 06 619 and DE--OSS-1957922 to drive valve timing gears of internal combustion engines with a toothed belt.
Such drive mechanisms frequently present difficulties resulting from the fact that both the crankshaft of an internal combustion engine and also the camshaft of the internal combustion engine do not rotate uniformly but are subject to torsional vibrations. Resonance in the valve gear can cause undesirable relative movements between gear wheel and toothed belt leading to premature wearing of the gear wheel and belt.
According to the invention there is provided a valve gear for an internal combustion comprising toothed wheels adapted to be fixed on the one hand to the crankshaft and on the other hand to the camshaft of an internal combustion engine and a toothed belt for effecting driving connection between the toothed wheels characterised in that the relative dimensions of the teeth of the belt and the teeth of the wheel are so chosen that backlash between the teeth on each wheel and the teeth on the belt is minimised.
By reducing the clearance between the teeth on the toothed belt and the adjacent teeth of the toothed wheel with which the belt engages vibrations of the toothed belt which produce noise and wear are avoided. This reduction of the normally provided clearance leads not only to the avoidance of vibrations of the toothed belt drive but also additionally to an absorption of the torsional vibrations of the shafts of the valve gear connected by the toothed belt.
Preferably the drive belt and the drive gear are provided with teeth having profiles as described in
German Patent Publication DE-B-1 9 57 922.
Such belts comprise a tensile member and teeth secured thereto, the teeth being curvilinear in profile, the tip of each both having a longitudinal cross sectional contour composed of two interesting areas of equal radii, the arcs being concave towards the tensile member.
The invention is illustrated with the aid of a preferred embodiment shown, by way of example only, in the drawing which is a schematic side view of one tooth of a toothed belt engaged between two teeth of a toothed wheel.
Referring to the drawing, a toothed belt 1 consists basically of an endless tensible member 3 and a plurality of moulded-on teeth 4 which is in driving engagement with two toothed wheels 2 connected respectively to the crankshaft and camshaft of an engine. The toothed wheels are similar in configuration. The recesses 5 between adjacent pairs of teeth are of similar shape and receive the teeth 4 of the tooth belt 1.
The teeth 4 and the recesses 5 have complementary profiles, and the teeth 4 are shaped in accordance with German Patent
Specification DAS 1 957922. Thus, each tooth has
a tip which has a longitudinal cross-sectional contour composed to two intersecting arcs of equal radius, said arcs being concave towards tensile member 3. Further details of the construction of the belt are set forth in German
Patent Specification No. 1 294 103 and British
Patent Specification No. 1294103 and will not therefore be repeated here.
The interengagement of the tooth 4 with the recess 5 provides a backlash or clearance X, which is the distance through which the centreline of the tooth on the belt can undergo movement relative to the wheel 2 from the position in which one flank of the tooth on the belt is engaged with one wall of the recess 5, to the position in which the other flank of the tooth is engaged with the opposite wall of the recess 5. In conventional valve drive gears, this distance has been about 0.020 inches (0.5 mm). According to the present invention however, this distance is reduced, preferably by about half, either by increasing the size of the tooth 4, or by decreasing the size of the recess 5. Typically, in accordance with the present invention the distance X/2 is about 0.0125 inches (0.3 mm) or less, e.g. 0.010 inches (0.25 mm).
1. Valve gear for an internal combustion engine comprising toothed wheels adapted to be fixed on the one hand to the crankshaft and on the other hand to the camshaft of an internal combustion engine and a toothed belt for effecting driving connection between the toothed wheels characterised in that the relative dimensions of the teeth of the belt and the teeth of the wheel are so chosen that backlash between the teeth on each wheel and the teeth on the belt is minimised.
2. A valve gear according to claim 1 wherein the toothed belt comprises a tensile member and teeth secured thereto, the teeth being curvilinear in profile, and the tip of each tooth having a longitudinal cross-sectional contour composed of two intersecting arcs of equal radii, said arcs being concave towards the tensile member.
3. Valve gear according to claim 1 or claim 2 wherein the distance by which a tooth on the toothed belt having one flank engaged with one wall of the recess between two adjacent teeth on the toothed wheel may move before the opposite flank of the tooth engages the opposite wall of the recess is less than 0.020 inches (0.5 mm).
4. Valve gear according to claim 3 wherein the said distance is not more than 0.0125 inches (0.3 mm).
**WARNING** end of DESC field may overlap start of CLMS **.
Claims (6)
1. Valve gear for an internal combustion engine comprising toothed wheels adapted to be fixed on the one hand to the crankshaft and on the other hand to the camshaft of an internal combustion engine and a toothed belt for effecting driving connection between the toothed wheels characterised in that the relative dimensions of the teeth of the belt and the teeth of the wheel are so chosen that backlash between the teeth on each wheel and the teeth on the belt is minimised.
2. A valve gear according to claim 1 wherein the toothed belt comprises a tensile member and teeth secured thereto, the teeth being curvilinear in profile, and the tip of each tooth having a longitudinal cross-sectional contour composed of two intersecting arcs of equal radii, said arcs being concave towards the tensile member.
3. Valve gear according to claim 1 or claim 2 wherein the distance by which a tooth on the toothed belt having one flank engaged with one wall of the recess between two adjacent teeth on the toothed wheel may move before the opposite flank of the tooth engages the opposite wall of the recess is less than 0.020 inches (0.5 mm).
4. Valve gear according to claim 3 wherein the said distance is not more than 0.0125 inches (0.3 mm).
5. Valve gear according to claim 3 wherein the said distance is not more than 0.010 inches (0.25 mm).
6. Valve gear substantially as hereinbefore described and as illustrated in the drawing.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19803034185 DE3034185C2 (en) | 1980-09-11 | 1980-09-11 | Control drive for internal combustion engines |
Publications (1)
Publication Number | Publication Date |
---|---|
GB2085999A true GB2085999A (en) | 1982-05-06 |
Family
ID=6111659
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB8127570A Withdrawn GB2085999A (en) | 1980-09-11 | 1981-09-11 | Valve gear for internal combustion engines |
Country Status (3)
Country | Link |
---|---|
DE (1) | DE3034185C2 (en) |
FR (1) | FR2489880A1 (en) |
GB (1) | GB2085999A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4515577A (en) * | 1982-10-20 | 1985-05-07 | Uniroyal, Inc. | Low backlash-high-torque power transmission system and toothed belt used therein |
US4604080A (en) * | 1983-10-12 | 1986-08-05 | Mitsuboshi Belting Ltd. | Toothed drive belt |
US4878886A (en) * | 1988-01-27 | 1989-11-07 | Bando Chemical Industries, Ltd. | Toothed belt and power transmission device using the same |
DE3590573C2 (en) * | 1984-11-15 | 1995-08-24 | Dayco Products Inc | Synchronous drive belt transmission |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102015223800A1 (en) | 2015-11-30 | 2017-06-01 | Contitech Antriebssysteme Gmbh | toothed belt drive |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3386301A (en) * | 1964-09-16 | 1968-06-04 | Koyama Mikio | Camshaft driving system for internal combustion engines |
ZA697698B (en) * | 1968-11-25 | 1971-06-30 | Uniroyal Inc | Positive power transmission system |
US4037485A (en) * | 1975-12-18 | 1977-07-26 | The Goodyear Tire & Rubber Company | Belt drive and belts and pulleys therefor |
-
1980
- 1980-09-11 DE DE19803034185 patent/DE3034185C2/en not_active Expired
-
1981
- 1981-09-03 FR FR8116774A patent/FR2489880A1/en not_active Withdrawn
- 1981-09-11 GB GB8127570A patent/GB2085999A/en not_active Withdrawn
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4515577A (en) * | 1982-10-20 | 1985-05-07 | Uniroyal, Inc. | Low backlash-high-torque power transmission system and toothed belt used therein |
US4604080A (en) * | 1983-10-12 | 1986-08-05 | Mitsuboshi Belting Ltd. | Toothed drive belt |
DE3590573C2 (en) * | 1984-11-15 | 1995-08-24 | Dayco Products Inc | Synchronous drive belt transmission |
US4878886A (en) * | 1988-01-27 | 1989-11-07 | Bando Chemical Industries, Ltd. | Toothed belt and power transmission device using the same |
Also Published As
Publication number | Publication date |
---|---|
DE3034185C2 (en) | 1982-09-16 |
DE3034185A1 (en) | 1982-03-25 |
FR2489880A1 (en) | 1982-03-12 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |