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WO1993007045A1 - Transmission possedant un element de traction et roue dentee associee - Google Patents

Transmission possedant un element de traction et roue dentee associee Download PDF

Info

Publication number
WO1993007045A1
WO1993007045A1 PCT/NL1992/000169 NL9200169W WO9307045A1 WO 1993007045 A1 WO1993007045 A1 WO 1993007045A1 NL 9200169 W NL9200169 W NL 9200169W WO 9307045 A1 WO9307045 A1 WO 9307045A1
Authority
WO
WIPO (PCT)
Prior art keywords
wheel
string
transmission according
discs
adjustment element
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.)
Ceased
Application number
PCT/NL1992/000169
Other languages
English (en)
Inventor
Harm Stevens
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.)
STEVENS ENGINEERING BV
Original Assignee
STEVENS ENGINEERING BV
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 STEVENS ENGINEERING BV filed Critical STEVENS ENGINEERING BV
Publication of WO1993007045A1 publication Critical patent/WO1993007045A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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
    • F16H9/00—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members
    • F16H9/02—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion
    • F16H9/24—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using chains or toothed belts, belts in the form of links; Chains or belts specially adapted to such gearing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
    • B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
    • B62M9/04—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio
    • B62M9/06—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like
    • B62M9/08—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving eccentrically- mounted or elliptically-shaped driving or driven wheel; with expansible driving or driven wheel
    • 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
    • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/32—Friction members
    • F16H55/52—Pulleys or friction discs of adjustable construction
    • F16H55/54—Pulleys or friction discs of adjustable construction of which the bearing parts are radially adjustable
    • 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
    • F16H9/00—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members
    • F16H9/02—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion
    • F16H9/04—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes
    • F16H9/10—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes engaging a pulley provided with radially-actuatable elements carrying the belt

Definitions

  • the invention relates to a transmission with a pulling element arranged over a driving wheel and a driven wheel, with both wheels and the pulling element being provided with corresponding teeth and recesses.
  • a transmission is known as a part of a bicycle for transmitting a rotary motion of a driving gear, connected with pedals via cranks, to a driven gear coaxial with the rear wheel.
  • the driven gear In order to provide several transmission ratios, it is known to make the driven gear, and usually the driving gear as well, of multiple design, with successive, adjacently arranged gears having increasing or decreasing numbers of teeth and the transmission being equipped with means for axial displacement of the pulling element designed as a chain.
  • a maximum of three driving gears and a maximum of seven driven gears are provided.
  • driving and driven gears which are located diametrically opposite each other cannot be used in combination. The number of transmissions that are available in practice is therefore smaller than the product of the number of driving and the number of driven gears.
  • a drawback of this known transmission is that relatively large differences occur between successive, available transmissions. This is the case in particular if a large spread of transmissions has been chosen.
  • this known transmission In addition to exhibiting the above-mentioned friction and wear when mutually misaligned gears are used, this known transmission moreover has the drawback that it is complicated and susceptible to failure, and particularly so according as the number of gears is greater.
  • the object of the invention is to provide a transmission in which the above-mentioned drawbacks have been obviated.
  • This object is achieved according to the present invention in that in a transmission of the type described in the preamble at least one of the wheels has a variable, adjustable effective diameter and is provided with a string, extending in circumferential direction, carrying the teeth of that wheel/ which string is anchored at at least one point so as to be restrained from rotation about the centreline of the wheel and has a neutral bending line which has substantially the same radius of curvature as the neutral bending line of the pulling element located over that string.
  • the toothed pulling element can nevertheless remain in engagement with the toothed wheel in that the teeth have been provided on a string extending in circumferential direction.
  • the effective diameter of the wheel is changed, the part of the string that adjoins the anchored part will move in circumferential direction, so that the pitch of the teeth can be maintained in correspondence with the pitch of the teeth of the pulling element riding over the wheel.
  • the teeth of the pulling element can thus remain in engagement with the teeth of the wheel whose effective diameter is changed.
  • the effective diameter can be changed in a stepped manner, in such a way that the number of teeth of the wheel increases or decreases by one at a time.
  • a maximum number of possibilities are available between the highest and the smallest number of teeth that can be ,set.
  • the pulling element may for instance be a conventional bicycle chain, in which case the pitch of the teeth remains equal at all times regardless of the effective diameter of the wheel.
  • the pulling element may also be provided with teeth projecting towards the wheel, as in the case of a geared belt, for instance.
  • the string must be so designed that the pitch of the teeth, in the case of a decreasing effective diameter, decreases in accordance with the effective pitch of a pulling element extending over the wheel.
  • the neutral line of the string should have substantially the same radius of curvature as the neutral line of a pulling element extending over that string.
  • Fig. 1 shows a side elevation in section, taken on the line I-I in Fig. 2, of a toothed wheel with a part of a pulling element for use in a transmission according to a practical embodiment of the present invention
  • Fig. 2 is a rear view in section taken on the line II-II in Fig. 1; and Fig. 3 is a side elevation similar to Fig. 1, of a rear part of a bicycle equipped with a transmission according to the present invention.
  • Fig. 3 shows an embodiment of the transmission according to the present invention adapted for use on a bicycle, represented in its entirety and in built-in condition.
  • the transmission comprises a pulling element 1 arranged over a driving wheel 2 and a driven wheel 3, with both wheels and the pulling element provided with corresponding teeth.
  • the pulling element is designed as a chain 1.
  • the chain rides over a bend wheel 4 and a chain tensioning wheel 5.
  • One of the wheels 2, 3 - the driven wheel 3, in this example - has a variable, adjustable effective diameter and is provided with a string 6 (Figs 1 and 2) , extending in circumferential direction, carrying the teeth of that wheel 3.
  • the wheel 3 is shown in solid lines in a first position and in broken lines in a second position with a smaller effective diameter.
  • the string 6 is anchored at at least one anchoring point 7 so as to be restrained from rotating about the axis 31 of the wheel 3.
  • the string in turn is designed as a toothed chain 6 having alternate wide links 8 and narrow links 9, which are connected by pivot pins 10.
  • the pivot pins 10 define a neutral bending line 11 of the toothed chain 6, which has the same radius of curvature as the neutral bending line 12 of the drive chain 1.
  • the teeth can be made in a simple manner from hard material, it may be of low elongation and is combinable with a conventional drive chain as pulling element.
  • the effective diameter of the wheel 3 is reduced, for instance, the part of the toothed chain 6 adjoining the anchoring point 7 rotates about the centreline of the wheel away from the anchoring point 7, so that the pitch of the teeth of the toothed chain 6 is not reduced proportionally to the effective diameter of the wheel 3, but remains adjusted to the pitch of the drive chain 1 located over the teeth.
  • the pitch remains the same at all times.
  • the effective diameter of the wheel 3 is increased, the reverse effect occurs.
  • one end 7 of the toothed chain 6 is anchored so as to be restrained from rotating about the centreline of the wheel 3.
  • the toothed chain 6 extends round from that one end 7 to a guide 13 near that one end 7 and further along that guide 13 to a central part 14 of the wheel 3.
  • a part of the toothed chain 6 that adjoins the other end 15 of the toothed chain 6 is located in the central part 14 of the wheel 3.
  • the other end 15 of the toothed chain 6 is connected to a resilient element 16 which keeps the toothed chain 6 wound up in the central part 14 of the wheel 3.
  • the resilient element 16 which is designed as a spiral spring, maintains the toothed chain 6 in a condition wherein it is pulled taut at all times, while upon increase of the effective diameter of the wheel 3 the resilient element 16 yields so that the required number of links can move towards the periphery of the wheel 3.
  • the string 6 need only permit of limited torsion to enable a given axial deflection thereof.
  • each tooth form with an undercut 37, i.e., one of the tooth flanks of that tooth recedes from the outside towards the inside.
  • the undercut is located on the outside of a link of the toothed chain, so that the free space between two successive teeth of the toothed chain is not reduced when the chain is being bent.
  • the wheel 3 having a variable effective diameter comprises a plurality of circumferentially distributed segments 17, 18 movable in radial direction.
  • the toothed chain 6 extends over surfaces of those segments 17, 18 that are remote from the centreline of the wheel.
  • each link 8, 9 is supported by at least one segment 17, 18.
  • the segments 17, 18 are provided with grooves 36, collectively forming a groove in circumferential direction, which guides the string 6 and supports it so as to prevent tilting.
  • One segment 18 is provided with an opening with the guide 13 along which the string 6 is bent from the effective outer circumference of the wheel to the central part 14, and is also connected with the anchored end 7 of the toothed chain 6.
  • the space between the last link of the toothed chain 6 and the last link of the chain that is still located along the effective outer circumference of the wheel 3 can thus be limited to a minimum.
  • the string 6 is located between two discs 19, 20, each provided with a conical surface 21, 22 facing the string 6. By moving the discs 19, 20 towards each other, the string 6 is urged outwards, so that the effective diameter of the wheel 3 is increased. Upon displacement of the discs 19, 20 away from each other, the reverse effect occurs.
  • only one of the discs may be provided with a conical surface and the other disc may for instance be flat. It is then of importance that steps have been taken to prevent the string 6 from tilting to the flat disc.
  • the wheel 3 For the mutual displacement of the discs 19 and 20, the wheel 3 comprises an adjustment element 23 provided with threads 24, 25 winding in opposite directions, extending around the centreline, and the discs 19 and 20 have threads 26 and 27 cooperating with threads 24, 25.
  • the adjustment element By turning the adjustment element relative to the discs 19, 20, the discs are moved towards each other or moved away from each other.
  • the use of threads offers the advantage that a large force enhancement can be obtained which makes it possible to move the discs 19, 20 towards each other even when a continuous driving force is exerted on the drive chain 1.
  • a further advantage of using threads for adjusting the distance between the discs 19, 20 is that if the pitch is sufficiently small, a self-braking system is obtained, which prevents adjustment by axial forces exerted on the discs.
  • the discs are connected to a wheel 29 for axial movement and restrained from rotation via pins 28.
  • a freewheel system may be provided between the discs 19, 20 and the wheel 29.
  • the adjustment element may also be provided with only one thread cooperating with one disc, while the other disc is axially fixed.
  • the transmission comprising means 32 for decelerating the adjustment element 23 relative to the discs 19, 20 and means 33 for accelerating the adjustment element 23 relative to the discs 19, 20.
  • the adjusting wheel 30 makes it possible to exert a relatively large moment on the adjustment element 23 and offers an enlarged area of engagement for the above-mentioned means for accelerating or decelerating the adjustment element 23 relative to the discs 19, 20.
  • the means 33 for accelerating the adjustment element 23 relative to the discs 19, 20 comprise a disc 34, driven by the pulling element 1, which disc can be brought into engagement with the adjusting wheel 30. This makes it possible to take off energy supplied by the pulling element 1 and to use it for energizing the adjustment element 23.
  • the disc 34 driven by the pulling element 1 is connected with the bend wheel 4 and in operation is moved along by it. By displacing this disc 34 in the direction indicated with an arrow 35, it can be brought into engagement with the adjusting wheel 30.
  • the means 32 for decelerating the adjustment element 23 relative to the discs 19, 20 are designed as a brake operated by a Bowden cable.
  • energy supplied by the pulling element 1 can be used for energizing the adjustment element 23.
  • the pitch of the threads 24, 25 of the adjustment element 23 and the slope of the conical parts 21, 22 of the discs 19, 20 are chosen such that a rotation of the adjustment element 23 through a certain angle relative to the discs 19, 20 results in a change by one tooth of the number of teeth of the string 6 located along the circumference.
  • stops are arranged for rotating the adjustment element 23 through the above-mentioned angle when the means 32 or 33 for rotating the adjustment element 23 relative to the discs 19, 20 are operated once.
  • the string 6 may be in direct abutment with the conical surfaces of the discs.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Transmissions By Endless Flexible Members (AREA)

Abstract

Elément de traction (1) disposé sur une roue motrice (2) et une roue menée (3). Les deux roues (2 et 3) et l'élément de traction (1) sont pourvus de dents et de concavités correspondantes. L'une au moins des roues (2, 3) présente un diamètre utile variable et réglable et est pourvue d'une courroie circonférentielle (6) portant les dents de cette roue (3). La courroie (6) est ancrée dans au moins un endroit (7) de manière qu'il lui soit impossible de tourner autour de la ligne médiane de la roue (3), et présente une ligne neutre de courbure (11) ayant sensiblement le même rayon de courbure que la ligne neutre de courbure (12) de l'élément de traction (1) se trouvant sur ladite courroie (6). On a prévu une roue dentée de transmission à diamètre utile variable.
PCT/NL1992/000169 1991-10-01 1992-09-30 Transmission possedant un element de traction et roue dentee associee Ceased WO1993007045A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL9101657A NL9101657A (nl) 1991-10-01 1991-10-01 Transmissie met een trekorgaan, alsmede een vertand wiel voor toepassing daarin.

Publications (1)

Publication Number Publication Date
WO1993007045A1 true WO1993007045A1 (fr) 1993-04-15

Family

ID=19859768

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NL1992/000169 Ceased WO1993007045A1 (fr) 1991-10-01 1992-09-30 Transmission possedant un element de traction et roue dentee associee

Country Status (2)

Country Link
NL (1) NL9101657A (fr)
WO (1) WO1993007045A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994004411A1 (fr) * 1992-08-21 1994-03-03 Baechtiger Rolf Engrenage a chaine a rapport de transmission variable et a chaine dentee
FR2715704A1 (fr) * 1994-02-03 1995-08-04 Nard Gilles Variateur de vitesse en continu à entraînement positif.
EP1072818A1 (fr) 1999-07-27 2001-01-31 Kenji Mimura Transmission
US6458054B1 (en) 1998-07-24 2002-10-01 Kenji Mimura Transmission
CN114857226A (zh) * 2022-01-21 2022-08-05 谭钢 一种电动无级自动变速器

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT202300013029A1 (it) * 2023-06-23 2024-12-23 Stefano Battaggia Cambio per bicicletta

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE727593C (de) * 1940-07-30 1942-11-06 Erwin Haeberlin Kettenraeder-Wechselgetriebe
EP0030992A1 (fr) * 1979-12-21 1981-07-01 Johann Ecker Elément d'engrenage
EP0084160A1 (fr) * 1981-12-23 1983-07-27 Kolbus GmbH & Co. KG Mécanisme d'entraînement à chaine
US5049113A (en) * 1990-10-15 1991-09-17 Graham Jr James A Variable circumference adjustable-drive pulley mechanism

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE727593C (de) * 1940-07-30 1942-11-06 Erwin Haeberlin Kettenraeder-Wechselgetriebe
EP0030992A1 (fr) * 1979-12-21 1981-07-01 Johann Ecker Elément d'engrenage
EP0084160A1 (fr) * 1981-12-23 1983-07-27 Kolbus GmbH & Co. KG Mécanisme d'entraînement à chaine
US5049113A (en) * 1990-10-15 1991-09-17 Graham Jr James A Variable circumference adjustable-drive pulley mechanism

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994004411A1 (fr) * 1992-08-21 1994-03-03 Baechtiger Rolf Engrenage a chaine a rapport de transmission variable et a chaine dentee
FR2715704A1 (fr) * 1994-02-03 1995-08-04 Nard Gilles Variateur de vitesse en continu à entraînement positif.
WO1995021340A1 (fr) * 1994-02-03 1995-08-10 Gilles Nard Variateur de vitesse en continu a entrainement positif
US6458054B1 (en) 1998-07-24 2002-10-01 Kenji Mimura Transmission
EP1072818A1 (fr) 1999-07-27 2001-01-31 Kenji Mimura Transmission
CN114857226A (zh) * 2022-01-21 2022-08-05 谭钢 一种电动无级自动变速器

Also Published As

Publication number Publication date
NL9101657A (nl) 1993-05-03

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