WO2007064206A1 - Courroie de transmission pour transmission à variation continue et élément transversal utilisé avec ladite courroie - Google Patents

Courroie de transmission pour transmission à variation continue et élément transversal utilisé avec ladite courroie Download PDF

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Publication number
WO2007064206A1
WO2007064206A1 PCT/NL2006/000613 NL2006000613W WO2007064206A1 WO 2007064206 A1 WO2007064206 A1 WO 2007064206A1 NL 2006000613 W NL2006000613 W NL 2006000613W WO 2007064206 A1 WO2007064206 A1 WO 2007064206A1
Authority
WO
WIPO (PCT)
Prior art keywords
drive belt
gullies
ridges
profile
elements
Prior art date
Application number
PCT/NL2006/000613
Other languages
English (en)
Inventor
Mark Van Drogen
Arjen Brandsma
Original Assignee
Robert Bosch Gmbh
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 Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Priority to EP06824289A priority Critical patent/EP1957827A1/fr
Publication of WO2007064206A1 publication Critical patent/WO2007064206A1/fr

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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
    • F16G5/00—V-belts, i.e. belts of tapered cross-section
    • F16G5/16—V-belts, i.e. belts of tapered cross-section consisting of several parts
    • 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
    • F16G5/00—V-belts, i.e. belts of tapered cross-section
    • F16G5/16—V-belts, i.e. belts of tapered cross-section consisting of several parts
    • F16G5/163—V-belts, i.e. belts of tapered cross-section consisting of several parts with means allowing lubrication

Definitions

  • the invention is related to a drive belt according to the preamble of claim 1.
  • a drive belt is generally known, more in particular from the European patent publication no. 0.994.275, and is often referred to as the Van Doorne belt or push belt.
  • the known drive belt comprises at least one endless tensile means or carrier and a plurality of plate-like transverse elements placed one after the other on the tensile means forming a nearly continuous string. The elements are supported and guided by the tensile means, but at the same time they are freely moveable along its circumference.
  • Such a drive belt is most commonly used in continuously variable transmissions or CVTs for motor vehicles, where it is wrapped around and in frictional contact with two pulleys for transmitting torque there between at a continuously variable transmission ratio, which transmission is also generally known, for example from WO-A-2003/021134.
  • An important aspect of the design and operation of such a transmission is the frictional contact between the belt, i.e. the transverse elements thereof, and the respective pulleys.
  • the side or pulley contact faces of the elements are highly loaded by a normal force and a predominantly tangentially oriented frictional force exerted thereon by the pulleys.
  • the said frictional contact is lubricated and the side faces of the elements are typically provided with a surface profile consisting of a plurality of ridges and gullies that extend width-wise thereon, i.e. essentially tangentially relative to the pulleys.
  • the present invention aims to improve the design of the element side face surface profile for realising a more robust and/or durable drive belt, based on a basic understanding of the fundamental behaviour of the frictional contact on a microscopic level. According to the invention this aim is realised by the drive belt of claim 1. It was found that at a constant level of the normal and friction forces the temperature of the lubricant in the frictional contact can be lowered by applying the measure of claim 1. Hereby, the durability of the belt is improved, or alternatively it may be subjected to higher force levels thus improving its robustness whilst maintaining its durability.
  • the invention relies on the observation that by refining the scale of the profile on the side faces of the elements, i.e. by incorporating thereon a larger number of smaller ridges and gullies, the maximum lubricant temperature occurring in the frictional contact could be reduced significantly. Practical considerations such as manufacturing limitations will normally limit the maximum attainable fineness of the profile, which feature of the invention is expressed in the dependent claim 4. For example, when using the known blanking process to form the transverse elements about 6-8 ridges and gullies can at most be formed per millimetre height of the side face. However, an even finer profile is in principle possible, for example by forming the gullies by electrochemical etching or laser cutting.
  • such a minimum width is prescribed by the manufacturing process for either one of the ridges or the gullies.
  • the minimum width of the ridges is typically limited to about 0.07 mm, whereas the width of the gullies may be set to a different value, i.e. both smaller and larger than such limiting value.
  • an optimum ratio was found to exist between the width of the ridges and the width of the gullies in terms of the lowest achievable lubricant temperature, which optimum ratio is 1 :1.
  • the above two surface profiles and particular advantages thereof can even be combined into one, thus providing the transverse element design of claim 6.
  • the surface profile of the side faces is composed of individual, i.e. isolated projecting plateau's (denoted protrusions hereinafter) surrounded by a continuous valley.
  • the protrusions are preferably provided in a hexagonal pattern in order to make optimal use of the available surface area.
  • Such surface profile was found to provide a minimal warming up of the lubricant in the frictional contact between the belt and the pulley.
  • the higher parts of the profile i.e.
  • the ridges or the protrusions preferably increase in cross-sectional area in downward direction towards the lower parts of the profile, i.e. the gullies or the valleys.
  • This feature provides a stable wearing-in of the belt, because as the height of the ridges or protrusions gradually decreases due to abrasive and/or tribo-chemical wear, their cross-section gradually increases so that the contact pressure between the elements and the pulley and the rate of wear that is associated therewith decreases as a consequence.
  • Figure 1 is a schematic representation in a perspective view of a known continuously variable transmission provided with a drive belt and two pulleys.
  • Figure 2 provides a front elevation of a transverse element of the known drive belt.
  • Figure 3 provides a schematic indication of a surface profile such as is typically provided on a side face of the transverse element for contacting the pulleys
  • Figure 4 is a graph illustrating the transmission's capacity to accommodate a speed difference or slip between its belt and pulley components in relation to the level of the normal force applied there between.
  • Figure 5 is a graph illustrating the relationship between a modelled temperature raise dT in the frictional contact between the belt and pulley components and the effect of a parameter of the surface profile thereon.
  • Figure 6 is a graph corresponding to the graph of figure 4, illustrating the effect of the orientation of the element's surface profile relative to a direction of the slip between the belt and pulley components.
  • Figure 7 provides a schematic indication of a preferred surface profile according to the invention.
  • Figure 1 shows the central parts of a known continuously variable transmission that is commonly applied in the drive line of motor vehicles between the engine and the driven wheels thereof.
  • the transmission comprises two pulleys 1 , 2, each provided with two pulley discs 4, 5, between which a push-type drive belt 3 is present for transmitting a rotational movement M and an accompanying torque from one pulley 1 , 2 to the other 2, 1.
  • the pulley discs 4, 5 are shaped generally conical and at least one pulley disc 4 of each pulley 1 , 2 is incorporated in the transmission axially moveable along a pulley shaft 6, 7 of the respective pulley 1 , 2.
  • the transmission normally also comprises activation means that impose on the said at least one movable disc 4 an axially oriented clamping force directed towards the respective other pulley disc 5 such that the drive belt 3 is clamped there between.
  • the drive belt 3 comprises an endless tensile means 31 and a plurality of relatively thin transverse elements 32 that are provided on the tensile means 31 movable along the longitudinal direction thereof and oriented predominantly transversely thereto.
  • the elements 32 take-up the said clamping force, such that at rotation of a driving pulley 1 , friction between the discs 4, 5 and the drive belt 3, causes the elements 32 to be thrust in the said direction of movement M from the said driving pulley 1 to a driven pulley 2 and back again, thereby being guided and supported by the tensile means 31.
  • FIG. 2 provides a front elevation of the known metal transverse element 32 that is incorporated in the drive belt 3 mounted on the endless tensile means 31 thereof, which, in this example, is shown to consist of two laminated parts, each part being formed by a number of thin and flat metal rings that are nested one around the other in the radial direction and being accommodated in a respective opening 33 of the transverse element 32.
  • the transverse element 32 comprises a body part 34, which is situated below or - relative to the radial direction- inside the tensile means 31 and which forms a bottom side of the openings 33.
  • a generally arrowhead-shaped head part 37 of the transverse element 32 forms a top side of the openings 33.
  • a so-called pillar part 38 of the transverse element 32 that connects the body part 34 and the head part 37 to each other.
  • the body part 34 is provided with essentially laterally oriented (i.e. laterally “facing"), side faces 36 for arriving into a frictional contact with the pulley discs 4, 5.
  • the transmission and in particular the frictional contact between the transverse elements 32 and the pulley discs 4, 5 is lubricated, whereby it is common practice to provide the side faces 36 with a surface profile to enhance the tribological properties of the said frictional contact.
  • a projecting pin 39 is provided on a front main face 40 of the transverse element
  • the body part 34 at least effectively tapers off in radially inward direction, so as to allow the belt 3 to assume a longitudinally curved trajectory at the pulleys 1 , 2, in which trajectory the transverse elements 32 tilt about their respective predominantly axially oriented tilting line 44 relative to a respectively adjacent element 32.
  • a section of the element 32 including part of a side face 36 thereof is depicted in the enlarged cross-section of figure 3. It is shown therein that the side face 36 is provided with an undulating surface profile 51, 52 consisting of a plurality of ridges 51 and gullies 52.
  • the surface profile 51 , 52 essentially covers the entire surface area of the side face 36, whereby the ridges 51 and the gullies 52 extend over the width of the side face 36, i.e. in the thickness direction of the element 32 in the circumference direction of the belt 3.
  • the above-described drive belt 3 and transmission is known to be able to withstand slippage, i.e.
  • FIG 2 which is based from the Dutch patent application number 1022242, illustrates this feature based on experimental data.
  • curve A it is defined by curve A as a function of the said normal force Fn and the amount of slip S whether or not under these operating conditions the transmission would be critically damaged to the extent that its operation is adversely affected thereby.
  • the position of the critical damage curve A can be influenced by the type and shape of the surface profile 51, 52.
  • the position of the critical damage curve A can also be influenced by the ratio between an effective width Wr of the ridges 51, i.e. the part of the profile actually in contact with the pulley discs 4, 5, and the width Wg of the gullies 52.
  • an optimum ratio was found to exist in terms of the lowest achievable lubricant temperature, which provides the best resistance against critical belt damage.
  • This latter effect is illustrated by curve C in figure 5, wherein a modelled temperature raise dT of the lubricant in the frictional contact is plotted against the ratio P defined as the effective width of the Wr of the ridges 51 divided by the width Wg of the gullies 52.
  • Curve C shows a minimum at a P-ratio of 1 :1.
  • the ridges 51 should preferably cover around 50% of the overall surface area of the side faces 36.
  • a further aspect of the invention is illustrated in a graph corresponding to the graph of figure 4.
  • the curves E and F of figure illustrate the effect of the orientation of an element's surface profile relative to a direction of the slip, i.e. the slip vector Sv between the belt and pulley components.
  • the critical damage curve E represents a conventional surface profile 51, 52, whereof the ridges 51 extend width- wise over the element's side face 36, i.e.
  • Figure 7 provides a schematic indication of a preferred surface profile 53, 54 for the side face 36 of the transverse element 32 according to the invention.
  • the profile 53, 54 is composed of individual, i.e. isolated protruding protrusions 53 surrounded by a continuous valley 54.
  • the protrusions 53 are preferably provided in a hexagonal pattern H in order to make optimal use of the available surface area.
  • This profile 53, 54 can be of similar scale as the former profile 51, 52, i.e. such that the protrusions 53 have a diameter Os of about 0.1 mm.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Transmissions By Endless Flexible Members (AREA)

Abstract

L'invention concerne une courroie de transmission (3) qui comprend un élément extensible sans fin (31) et un certain nombre d'éléments transversaux relativement fins (32), lesquels sont montés coulissants sur l'élément extensible (31) et possèdent une face principale avant (40) et une face principale arrière (41) qui sont séparées sur une épaisseur de l'élément (32) et qui sont orientées principalement dans le sens longitudinal de la courroie de transmission (3). Lesdits éléments (32) possèdent également deux faces latérales (36) orientées principalement de manière latérale, chacune étant située sur chaque partie latérale de l'élément (32) afin d'être soumise à un contact par friction avec une poulie (1, 2) d'une transmission dans laquelle la courroie (3) est utilisée. Chaque face latérale (36) présente un profil de surface (51, 52) qui comprend des parties saillantes (51) séparées par des parties évidées (52), la largeur combinée des parties saillantes (Wr) et des parties évidées (Wg) étant inférieure à 0,15 mm.
PCT/NL2006/000613 2005-12-02 2006-12-04 Courroie de transmission pour transmission à variation continue et élément transversal utilisé avec ladite courroie WO2007064206A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP06824289A EP1957827A1 (fr) 2005-12-02 2006-12-04 Courroie de transmission pour transmission a variation continue et element transversal utilise avec ladite courroie

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NLPCT/NL2005/000830 2005-12-02
NL2005000830 2005-12-02

Publications (1)

Publication Number Publication Date
WO2007064206A1 true WO2007064206A1 (fr) 2007-06-07

Family

ID=37808141

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NL2006/000613 WO2007064206A1 (fr) 2005-12-02 2006-12-04 Courroie de transmission pour transmission à variation continue et élément transversal utilisé avec ladite courroie

Country Status (2)

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EP (1) EP1957827A1 (fr)
WO (1) WO2007064206A1 (fr)

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60252840A (ja) * 1984-05-30 1985-12-13 Toyota Motor Corp 伝導ベルト用ブロツク
JPS6288844A (ja) * 1985-10-12 1987-04-23 Toyota Motor Corp 伝導ベルト用金属ブロツク
EP0381258A1 (fr) * 1989-02-03 1990-08-08 Van Doorne's Transmissie B.V. Transmission comprenant une courroie et des poulies en "V"
EP0994275A1 (fr) 1998-10-12 2000-04-19 Van Doorne's Transmissie B.V. Courroie de transmission, élément pour celle-çi et ensemble l'utilisant
US6440024B1 (en) * 1999-06-22 2002-08-27 Nissan Motor Co., Ltd. Belt-drive continuously variable transmission
WO2003021134A1 (fr) 2001-09-04 2003-03-13 Van Doorne's Transmissie B.V. Transmission variable en continu efficace, a couple eleve
JP2004144110A (ja) * 2002-10-21 2004-05-20 Toyota Motor Corp 無段変速機用の伝動ベルト
NL1022242C2 (nl) 2002-12-23 2004-06-24 Doornes Transmissie Bv Werkwijze voor het bedienen van een continu variabele transmissie.
EP1455114A2 (fr) * 2003-03-06 2004-09-08 Nissan Motor Co., Ltd. Courroie en V métallique

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1549403A (en) * 1975-10-09 1979-08-08 Doornes Transmissie Bv V-belt transmission
JP4839369B2 (ja) * 2005-06-13 2011-12-21 ロベルト ボッシュ ゲゼルシャフト ミト ベシュレンクテル ハフツング 無段変速装置用駆動ベルトとこのような駆動ベルト用の横方向エレメントの製作方法

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60252840A (ja) * 1984-05-30 1985-12-13 Toyota Motor Corp 伝導ベルト用ブロツク
JPS6288844A (ja) * 1985-10-12 1987-04-23 Toyota Motor Corp 伝導ベルト用金属ブロツク
EP0381258A1 (fr) * 1989-02-03 1990-08-08 Van Doorne's Transmissie B.V. Transmission comprenant une courroie et des poulies en "V"
EP0994275A1 (fr) 1998-10-12 2000-04-19 Van Doorne's Transmissie B.V. Courroie de transmission, élément pour celle-çi et ensemble l'utilisant
US6440024B1 (en) * 1999-06-22 2002-08-27 Nissan Motor Co., Ltd. Belt-drive continuously variable transmission
WO2003021134A1 (fr) 2001-09-04 2003-03-13 Van Doorne's Transmissie B.V. Transmission variable en continu efficace, a couple eleve
JP2004144110A (ja) * 2002-10-21 2004-05-20 Toyota Motor Corp 無段変速機用の伝動ベルト
NL1022242C2 (nl) 2002-12-23 2004-06-24 Doornes Transmissie Bv Werkwijze voor het bedienen van een continu variabele transmissie.
EP1455114A2 (fr) * 2003-03-06 2004-09-08 Nissan Motor Co., Ltd. Courroie en V métallique

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP1957827A1 *

Also Published As

Publication number Publication date
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