GB2094439A - Toothed belt and valve gear for an internal combustion engine - Google Patents

Toothed belt and valve gear for an internal combustion engine Download PDF

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Publication number
GB2094439A
GB2094439A GB8207177A GB8207177A GB2094439A GB 2094439 A GB2094439 A GB 2094439A GB 8207177 A GB8207177 A GB 8207177A GB 8207177 A GB8207177 A GB 8207177A GB 2094439 A GB2094439 A GB 2094439A
Authority
GB
United Kingdom
Prior art keywords
toothed belt
teeth
valve gear
toothed
belt
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
GB8207177A
Other versions
GB2094439B (en
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.)
Ford Motor Co Ltd
Ford Motor Co
Original Assignee
Ford Motor Co Ltd
Ford Motor 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 Ford Motor Co Ltd, Ford Motor Co filed Critical Ford Motor Co Ltd
Publication of GB2094439A publication Critical patent/GB2094439A/en
Application granted granted Critical
Publication of GB2094439B publication Critical patent/GB2094439B/en
Expired 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
    • F16G—BELTS, CABLES, OR ROPES, PREDOMINANTLY USED FOR DRIVING PURPOSES; CHAINS; FITTINGS PREDOMINANTLY USED THEREFOR
    • F16G1/00—Driving-belts
    • F16G1/28—Driving-belts with a contact surface of special shape, e.g. toothed
    • 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

Abstract

The invention relates to a valve gear in which the camshaft is driven by a toothed belt passing over a toothed camshaft pulley. To reduce belt noise the invention proposes teeth 6 of varying pitch on the belt 5 and on the pulleys. <IMAGE>

Description

SPECIFICATION Toothed belt and valve gear for an internal combustion engine The present invention relates to a toothed belt and valve gear for an internal combustion engine.
Almost all toothed belts used for the purpose of driving an overhead camshaft produce noise to a greater or lesser extent. These noises are of various types, ranging from "rattling" through "whispering" to "howling" and almost all are caused by the fact that the straight runs of the toothed belt are caused to vibrate as the teeth on the belt move into and out of engagement with the toothed belt pulleys.
From German Patent No. 2906619 a valve gear is already known, in which to avoid toothed belt noises it is suggested that consecutive teeth be provided with notches of varying arrangement and varying depth in order to avoid resonance.
The present invention relates to an alternative method of reducing toothed belt noises.
According to one aspect of the invention, there is provided a valve gear as herein set forth in
Claim 1.
According to a second aspect of the invention, there is provided a toothed belt as set forth in Claim 7.
The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows schematically a known toothed belt for driving a valve gear, and Figure 2 is a similar view of a toothed belt according to the invention.
Fig. 1 shows in basic diagrammatic form a toothed belt 1 which consists of an endless tension member having a number of moulded teeth 3. The teeth 3 are at an equal distance from each other which also corresponds to the tooth pitch of the toothed belt pulleys.
Fig. 2 shows a toothed belt 4 according to the invention which consists essentially of an endless tension member 5 and a number of moulded teeth 6 of equal shape. The teeth 6, however, in this case are at differing distances from each other P 1, P2, and P3. The distances P 1, P2 and P3 are repeated after an interval N which may be designated as the period. Accordingly corresponding gaps must be disposed on the toothed belt pulleys in an integral arrangement of the period N.
The distances P1, P2 and P3 within one period N are related to each other in such a manner that P 1 is smaller than P2 and P2 is smaller than P3.
Alternatively, the distances P 1, P2 and P3 may correspond to a random distribution. The ratio of P1 to P2 and to P3 should not be integral.
Preferably, the period N can cover a number of teeth 6 which corresponds to a complete toothing (e.g. 20 teeth) of a crankshaft toothed belt pulley.
Since the crankshaft toothed belt pulley must always have twice as many teeth, this would then bear two periods N.
Neither the manufacture of toothed belts with such an uneven tooth pitch nor the manufacture of corresponding toothed belt pulleys presents fundamental problems, since on the one hand the toothed belts in their endless form are manufactured in corresponding moulds and on the other hand corresponding toothed belt pulleys can likewise be sintered in moulds, without subsequently requiring any kind of processing of the teeth. Since the manufacture of correspondingly unequal toothed belts and toothed belts pulleys presents no difficulties, it can be seen that in this way toothed belt noises, caused by even vibrations can be avoided by the use of unequal pitch.
CLAIMS 1. A valve gear for an internal combustion engine in which a toothed belt serves to drive a toothed pulley on the camshaft from a toothed pulley on the crankshaft, in which the teeth on the belt and on the pulleys are unevenly spaced.
2. A valve gear as claimed in Claim 1, in which the spacings between the teeth vary periodically with period N.
3. A valve gear as claimed in Claim 2 in which three predetermined spacings P1, P2 and P3 repeat periodically.
4. A valve gear as claimed in Claim 2, in which P1 > P2 > P3.
5. A valve gear as claimed in Claim 2 or 3, in which the spacings P1, P2 and P3 are not in an integral ratio to each other.
6. A valve gear as claimed in Claim 1, in which no spacing occurs more than once over the circumference of the toothed crankshaft pulley.
7. A toothed belt for a valve gear of an internal combustion engine having drive teeth unevenly distributed, the sequence of the spacings between adjacent teeth repeating cyclically over the length of the belt.
8. A toothed belt constructed substantially as herein described with reference to and as illustrated in Fig. 2 of the accompanying drawings.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (8)

    **WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Toothed belt and valve gear for an internal combustion engine The present invention relates to a toothed belt and valve gear for an internal combustion engine. Almost all toothed belts used for the purpose of driving an overhead camshaft produce noise to a greater or lesser extent. These noises are of various types, ranging from "rattling" through "whispering" to "howling" and almost all are caused by the fact that the straight runs of the toothed belt are caused to vibrate as the teeth on the belt move into and out of engagement with the toothed belt pulleys. From German Patent No. 2906619 a valve gear is already known, in which to avoid toothed belt noises it is suggested that consecutive teeth be provided with notches of varying arrangement and varying depth in order to avoid resonance. The present invention relates to an alternative method of reducing toothed belt noises. According to one aspect of the invention, there is provided a valve gear as herein set forth in
  1. Claim 1.
    According to a second aspect of the invention, there is provided a toothed belt as set forth in Claim 7.
    The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows schematically a known toothed belt for driving a valve gear, and Figure 2 is a similar view of a toothed belt according to the invention.
    Fig. 1 shows in basic diagrammatic form a toothed belt 1 which consists of an endless tension member having a number of moulded teeth 3. The teeth 3 are at an equal distance from each other which also corresponds to the tooth pitch of the toothed belt pulleys.
    Fig. 2 shows a toothed belt 4 according to the invention which consists essentially of an endless tension member 5 and a number of moulded teeth
    6 of equal shape. The teeth 6, however, in this case are at differing distances from each other P 1, P2, and P3. The distances P 1, P2 and P3 are repeated after an interval N which may be designated as the period. Accordingly corresponding gaps must be disposed on the toothed belt pulleys in an integral arrangement of the period N.
    The distances P1, P2 and P3 within one period N are related to each other in such a manner that P 1 is smaller than P2 and P2 is smaller than P3.
    Alternatively, the distances P 1, P2 and P3 may correspond to a random distribution. The ratio of P1 to P2 and to P3 should not be integral.
    Preferably, the period N can cover a number of teeth 6 which corresponds to a complete toothing (e.g. 20 teeth) of a crankshaft toothed belt pulley.
    Since the crankshaft toothed belt pulley must always have twice as many teeth, this would then bear two periods N.
    Neither the manufacture of toothed belts with such an uneven tooth pitch nor the manufacture of corresponding toothed belt pulleys presents fundamental problems, since on the one hand the toothed belts in their endless form are manufactured in corresponding moulds and on the other hand corresponding toothed belt pulleys can likewise be sintered in moulds, without subsequently requiring any kind of processing of the teeth. Since the manufacture of correspondingly unequal toothed belts and toothed belts pulleys presents no difficulties, it can be seen that in this way toothed belt noises, caused by even vibrations can be avoided by the use of unequal pitch.
    CLAIMS 1. A valve gear for an internal combustion engine in which a toothed belt serves to drive a toothed pulley on the camshaft from a toothed pulley on the crankshaft, in which the teeth on the belt and on the pulleys are unevenly spaced.
  2. 2. A valve gear as claimed in Claim 1, in which the spacings between the teeth vary periodically with period N.
  3. 3. A valve gear as claimed in Claim 2 in which three predetermined spacings P1, P2 and P3 repeat periodically.
  4. 4. A valve gear as claimed in Claim 2, in which P1 > P2 > P3.
  5. 5. A valve gear as claimed in Claim 2 or 3, in which the spacings P1, P2 and P3 are not in an integral ratio to each other.
  6. 6. A valve gear as claimed in Claim 1, in which no spacing occurs more than once over the circumference of the toothed crankshaft pulley.
  7. 7. A toothed belt for a valve gear of an internal combustion engine having drive teeth unevenly distributed, the sequence of the spacings between adjacent teeth repeating cyclically over the length of the belt.
  8. 8. A toothed belt constructed substantially as herein described with reference to and as illustrated in Fig. 2 of the accompanying drawings.
GB8207177A 1981-03-11 1982-03-11 Toothed belt and valve gear for an internal combustion engine Expired GB2094439B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19813109172 DE3109172C2 (en) 1981-03-11 1981-03-11 Control drive for internal combustion engines

Publications (2)

Publication Number Publication Date
GB2094439A true GB2094439A (en) 1982-09-15
GB2094439B GB2094439B (en) 1985-01-09

Family

ID=6126876

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8207177A Expired GB2094439B (en) 1981-03-11 1982-03-11 Toothed belt and valve gear for an internal combustion engine

Country Status (2)

Country Link
DE (1) DE3109172C2 (en)
GB (1) GB2094439B (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6050916A (en) * 1996-11-22 2000-04-18 Volkswagen Ag Toothed belt or chain drive arrangement having a tooth with different flank geometry from other teeth
US6949211B2 (en) 2003-04-16 2005-09-27 The Goodyear & Rubber Company Means of manufacturing plural optimized cogged drive belts
US7008341B2 (en) 2001-06-27 2006-03-07 The Goodyear Tire & Rubber Company Reduced noise multi-ribbed power transmission belt
WO2007063035A1 (en) * 2005-12-01 2007-06-07 Contitech Antriebssysteme Gmbh Toothed belt drive

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
PT946834E (en) 1996-11-22 2001-10-30 Volkswagen Ag BELT TRANSMISSION OR TRANSMISSION BY CURRENT
DE102004055127A1 (en) * 2004-11-16 2006-06-29 Volkswagen Ag Toothed belt for electromechanical steering system includes belt base body of constant cross section, teeth and slub inserts
DE102006046520A1 (en) * 2006-09-29 2008-04-03 Luk Lamellen Und Kupplungsbau Beteiligungs Kg Chain drive used in engine construction comprises a small chain wheel divided into two or more first peripheral sections and a large chain wheel divided into a number of further second peripheral sections with divisions

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3029654A (en) * 1960-09-14 1962-04-17 Ferguson Res Ltd Harry Chain-and-sprocket drives
DE2906619C2 (en) * 1979-02-21 1981-05-21 Bayerische Motoren Werke AG, 8000 München Timing belt

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6050916A (en) * 1996-11-22 2000-04-18 Volkswagen Ag Toothed belt or chain drive arrangement having a tooth with different flank geometry from other teeth
US7008341B2 (en) 2001-06-27 2006-03-07 The Goodyear Tire & Rubber Company Reduced noise multi-ribbed power transmission belt
US6949211B2 (en) 2003-04-16 2005-09-27 The Goodyear & Rubber Company Means of manufacturing plural optimized cogged drive belts
WO2007063035A1 (en) * 2005-12-01 2007-06-07 Contitech Antriebssysteme Gmbh Toothed belt drive

Also Published As

Publication number Publication date
DE3109172A1 (en) 1982-09-23
GB2094439B (en) 1985-01-09
DE3109172C2 (en) 1984-03-01

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Legal Events

Date Code Title Description
746 Register noted 'licences of right' (sect. 46/1977)
PCNP Patent ceased through non-payment of renewal fee