EP2235397A1 - Transmission à variation continue incorporant une courroie d'entraînement, procédé de fonctionnement de cette transmission et procédé de fabrication de la courroie d'entraînement - Google Patents

Transmission à variation continue incorporant une courroie d'entraînement, procédé de fonctionnement de cette transmission et procédé de fabrication de la courroie d'entraînement

Info

Publication number
EP2235397A1
EP2235397A1 EP07857668A EP07857668A EP2235397A1 EP 2235397 A1 EP2235397 A1 EP 2235397A1 EP 07857668 A EP07857668 A EP 07857668A EP 07857668 A EP07857668 A EP 07857668A EP 2235397 A1 EP2235397 A1 EP 2235397A1
Authority
EP
European Patent Office
Prior art keywords
hrc
belt
transverse elements
value
cooling
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Withdrawn
Application number
EP07857668A
Other languages
German (de)
English (en)
Inventor
Cornelis Johannes Maria Van Der Meer
Gavrila Szots-Pollak
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.)
Robert Bosch GmbH
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
Publication of EP2235397A1 publication Critical patent/EP2235397A1/fr
Withdrawn legal-status Critical Current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
    • F16H57/00—General details of gearing
    • F16H57/04—Features relating to lubrication or cooling or heating
    • F16H57/048—Type of gearings to be lubricated, cooled or heated
    • F16H57/0487—Friction gearings
    • F16H57/0489—Friction gearings with endless flexible members, e.g. belt CVTs
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • 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
    • 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
    • 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
    • F16H9/12—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 built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members
    • F16H9/16—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 built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members using two pulleys, both built-up out of adjustable conical parts
    • F16H9/18—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 built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members using two pulleys, both built-up out of adjustable conical parts only one flange of each pulley being adjustable

Definitions

  • the present invention relates to the continuously variable transmission according to the preamble of the following claim 1 , which transmission is well known in the art, for example from the European patent EP-A- 1 167 829.
  • Such a transmission typically comprises a drive belt in the form of a so-called pushbelt that is known per se, for example from the European patent EP-A-O 626 526.
  • the known pushbelt comprises steel transverse elements that are freely slidingly included in the belt relative to the circumference of an endless tensile means thereof that primarily has the function of confining and guiding the transverse elements.
  • the endless tensile means is composed of two sets of a number a mutually nested, i.e. radially stacked flat and thin metal rings.
  • a torque is transferred from one pulley to the other by clamping the belt between conical steel discs of the respective pulley under the influence of a clamping force, for which purpose at least one disc of the pulley is included axially moveable by means of an actuator.
  • the said transfer of torque is realized by frictionally transferring a rotational movement of a driving pulley to the belt, of which the elements are provided with axial contact areas for contacting the discs of the pulley.
  • the force underlying said rotational movement of the driving pulley is conversely and also frictionally transferred from said belt to the discs of the driven pulley.
  • the radius at which the belt runs in each pulley can be changed by changing the clamping force at each pulley in relation to one another, hereby a mathematical quotient between such radii represents a so- called geometric ratio of the transmission, whereas a ratio between the rotational speeds of the pulleys represents the actual speed ratio of the transmission.
  • the transverse elements of the belt are normally the most critical components, since the steel thereof has been hardened by heating (austenizing), quenching and subsequent tempering in order to be able to reliably cope with the high level of the said clamping force typically applied in contemporary transmission designs. If heated above a certain critical temperature, the tempering process would continue and the transverse elements would wear-out rapidly or even break under the influence of the clamping force.
  • the known transmission further includes a cooling device for supplying a cooling agent, such as a synthetic lubrication oil to the belt and subsequently re- circulating it via a reservoir by means of a pump, which known cooling device further includes a component for cooling the cooling agent itself, i.e. a heat exchange device such as an oil cooler.
  • a cooling agent such as a synthetic lubrication oil
  • the above object is realized by a transmission incorporating the features of the characterizing portion of claim 1 .
  • the present invention has found a solution not in optimizing the cooling device it self, but surprisingly in modifying the design of the transmission in such a manner that the cooling effort required thereby is reduced in the first place.
  • the invention departs from the notion that the material hardness specified for the transverse elements is actually required only as surface hardness for coping with the wear and tear of the frictional contact with the pulley discs. In principle a considerably lower core hardness value could be allowed for the transverse elements, while still providing a sufficient strength.
  • the transverse elements are additionally hardened by a surface, i.e.
  • the quench hardened core material of the element can thus be allowed to be tempered to a considerably lower core hardness value, possibly even during operation of the transmission. Accordingly, a thus designed transmission can be operated at a considerably higher temperature so that the cooling effort required thereby is reduced. In practice this means that the minimally required supply flow of the cooling agent is favorably reduced and/or that the maximally allowed supply temperature of the cooling agent is favorably increased.
  • the invention relates to a continuously variable transmission incorporating a cooling device that is, however, not equipped with a heat exchange device such as an oil cooler.
  • a heat exchange device such as an oil cooler.
  • the supply temperature of the cooling agent during operation of the transmission is limited to about 80-90 0 C, whereas in the transmission according to the present invention a supply temperature of more than 100 0 C can be easily allowed, potentially over 1 1 O 0 C and up to 125 0 C, possibly even slightly beyond, e.g. up to 130 0 C.
  • a supply temperature of more than 100 0 C can be easily allowed, potentially over 1 1 O 0 C and up to 125 0 C, possibly even slightly beyond, e.g. up to 130 0 C.
  • the invention also relates to a method for operating a continuously variable transmission provided with a cooling device for cooling a belt of the transmission by continuously supplying a flow of a cooling agent to the belt.
  • the supply flow of the cooling agent is regulated such that its temperature reaches 100 0 C or more during operation.
  • either the said supply flow can be substantially reduced relative to the conventionally applied flow and/or the cooling capacity of the conventionally applied heat exchange device can be reduced in size, or potentially can even be omitted from the transmission altogether.
  • the additional surface hardness of the transverse elements may be realized by incorporating one of several well known case hardening treatments that do not rely on the phase transformation of the steel matrix (from austenite to martensite), such as coating with a suitable coating material, e.g. titanium nitride, shot-peening and or (carbo-)nitriding, in the manufacturing of the drive belt.
  • a suitable coating material e.g. titanium nitride, shot-peening and or (carbo-)nitriding
  • the method for manufacturing the drive belt preferably includes the combined case and core hardening the transverse elements by the said steps of austenizing and quenching the elements and subsequently subjecting the elements to the process step of simultaneous tempering and nitriding in a process atmosphere containing, for example, ammonia.
  • the austenizing is performed in a carburizing process atmosphere.
  • This latter carburizing process may, however, also be performed prior to the process step of core hardening the transverse elements in a hot and carbon-rich environment, for example by first immersing the elements in a molten salt.
  • the ultimate core hardness of the transverse elements has a value between 54 and 64 HRC (Hardness on Rockwell C-scale), more preferably between 56 and 60 HRC, whereas the surface hardness of the transverse elements amounts to more than 60 HRC, more preferably over 64 HRC.
  • the pulley discs are additionally hardened by a case hardening treatment, preferably reaching a surface hardness that is comparable to, i.e. has a value that deviates less than 4 HRC-points, more preferably less than 5% from the surface hardness value of the transverse elements.
  • a case hardening treatment preferably reaching a surface hardness that is comparable to, i.e. has a value that deviates less than 4 HRC-points, more preferably less than 5% from the surface hardness value of the transverse elements.
  • the core material of the pulley discs softer and thus more ductile than its surface.
  • the pulley discs are provided with a core hardness having a value between 50 and 60 HRC.
  • the invention is particularly suited for being applied in a transmission having convexly curved pulley discs, such as is known from, for example, WO-A- 2006/062400.
  • a transmission having convexly curved pulley discs such as is known from, for example, WO-A- 2006/062400.
  • the difference between the respectively required element's surface and core hardness values is especially significant, because of the highly concentrated frictional contact between the pulley discs and the belt's transverse elements thereof.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Transmissions By Endless Flexible Members (AREA)
  • Heat Treatment Of Articles (AREA)
  • General Details Of Gearings (AREA)

Abstract

L'invention porte sur une transmission à variation continue. Ladite transmission comporte deux poulies définissant chacune une gorge circonférentielle réellement en forme de V, de largeur variable ; une courroie d'entraînement enroulée autour des poulies et munie d'un grand nombre d'éléments transversaux en acier cémenté disposés sur des moyens de traction sans fin de la courroie ; un dispositif de refroidissement pour refroidir la courroie durant le fonctionnement de la transmission par distribution d'un agent de refroidissement sur la courroie d'une manière à recirculation. Selon l'invention, la transmission ne comprend pas un composant d'amélioration du refroidissement de l'agent de refroidissement lui-même, ou autrement spécifiquement destiné au refroidissement de l'agent de refroidissement lui-même.
EP07857668A 2007-12-17 2007-12-17 Transmission à variation continue incorporant une courroie d'entraînement, procédé de fonctionnement de cette transmission et procédé de fabrication de la courroie d'entraînement Withdrawn EP2235397A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2007/064037 WO2009076999A1 (fr) 2007-12-17 2007-12-17 Transmission à variation continue incorporant une courroie d'entraînement, procédé de fonctionnement de cette transmission et procédé de fabrication de la courroie d'entraînement

Publications (1)

Publication Number Publication Date
EP2235397A1 true EP2235397A1 (fr) 2010-10-06

Family

ID=39712591

Family Applications (1)

Application Number Title Priority Date Filing Date
EP07857668A Withdrawn EP2235397A1 (fr) 2007-12-17 2007-12-17 Transmission à variation continue incorporant une courroie d'entraînement, procédé de fonctionnement de cette transmission et procédé de fabrication de la courroie d'entraînement

Country Status (5)

Country Link
EP (1) EP2235397A1 (fr)
JP (1) JP5812604B2 (fr)
KR (1) KR20100096249A (fr)
CN (1) CN101903685B (fr)
WO (1) WO2009076999A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL2003033C2 (en) * 2009-06-17 2010-12-20 Bosch Gmbh Robert Method for operating a continuously variable transmission incorporating a drive belt.
NL1041640B1 (en) * 2015-12-22 2017-07-03 Bosch Gmbh Robert Transverse element for a drive belt, drive belt and method for manufacturing such a transverse element.

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01234638A (ja) * 1988-03-14 1989-09-19 Toyota Motor Corp チェーンベルト用ｖブロック
US20030195073A1 (en) * 2001-02-16 2003-10-16 Honda Giken Kogyo Kabushiki Kaisha Pushing block for CVT belt and manufacturing method therefor

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62196439A (ja) * 1986-02-21 1987-08-29 Toyota Motor Corp ベルト式無段変速機
JPS62196444A (ja) * 1986-02-21 1987-08-29 Toyota Motor Corp ベルト式無段変速機
JPH01269761A (ja) * 1988-04-21 1989-10-27 Mazda Motor Corp ベルト式無段変速機の制御装置
JP2973666B2 (ja) * 1991-12-03 1999-11-08 トヨタ自動車株式会社 車両用ベルト式無段変速機
JP3209323B2 (ja) * 1996-10-11 2001-09-17 日産自動車株式会社 ベルト型無段変速機用板状エレメントおよびベルトならびにベルト型無段変速機
JPH10141459A (ja) * 1996-11-05 1998-05-29 Nissan Motor Co Ltd ベルト式無段変速機の潤滑装置
DE10026223A1 (de) * 1999-06-16 2001-01-25 Luk Lamellen & Kupplungsbau Verfahren zum Bestimmen der Lebensdauer eines Fluids, insbesondere eines Öls
JP2003056649A (ja) * 2001-08-10 2003-02-26 Honda Motor Co Ltd 無段変速機用ベルト
JP3938897B2 (ja) * 2002-09-30 2007-06-27 ジヤトコ株式会社 ベルト式無段変速機の油圧制御装置
JP4973972B2 (ja) * 2003-08-22 2012-07-11 日産自動車株式会社 無段変速機用低摩擦摺動部材及びこれに用いる無段変速機油組成物
NL1027685C2 (nl) * 2004-12-08 2006-06-09 Bosch Gmbh Robert Drijfriem voor een transmissie met gebombeerde poelieschijven.
ATE475035T1 (de) * 2005-11-08 2010-08-15 Bosch Gmbh Robert Getriebe mit riemenscheiben und treibriemen

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01234638A (ja) * 1988-03-14 1989-09-19 Toyota Motor Corp チェーンベルト用ｖブロック
US20030195073A1 (en) * 2001-02-16 2003-10-16 Honda Giken Kogyo Kabushiki Kaisha Pushing block for CVT belt and manufacturing method therefor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO2009076999A1 *

Also Published As

Publication number Publication date
WO2009076999A1 (fr) 2009-06-25
CN101903685B (zh) 2015-07-22
JP5812604B2 (ja) 2015-11-17
CN101903685A (zh) 2010-12-01
JP2011506885A (ja) 2011-03-03
KR20100096249A (ko) 2010-09-01

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