WO2009076999A1 - Continuously variable transmission incorporating a drive belt, method for operating it and method for manufacturing the drive belt - Google Patents
Continuously variable transmission incorporating a drive belt, method for operating it and method for manufacturing the drive belt Download PDFInfo
- Publication number
- WO2009076999A1 WO2009076999A1 PCT/EP2007/064037 EP2007064037W WO2009076999A1 WO 2009076999 A1 WO2009076999 A1 WO 2009076999A1 EP 2007064037 W EP2007064037 W EP 2007064037W WO 2009076999 A1 WO2009076999 A1 WO 2009076999A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- hrc
- belt
- transverse elements
- value
- cooling
- Prior art date
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
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020107015826A KR20100096249A (en) | 2007-12-17 | 2007-12-17 | Continuously variable transmission incorporating a drive belt, method for operating it and method for manufacturing the drive belt |
PCT/EP2007/064037 WO2009076999A1 (en) | 2007-12-17 | 2007-12-17 | Continuously variable transmission incorporating a drive belt, method for operating it and method for manufacturing the drive belt |
CN200780101958.8A CN101903685B (en) | 2007-12-17 | 2007-12-17 | Continuously variable transmission incorporating a drive belt, method for operating it and method for manufacturing the drive belt |
EP07857668A EP2235397A1 (en) | 2007-12-17 | 2007-12-17 | Continuously variable transmission incorporating a drive belt, method for operating it and method for manufacturing the drive belt |
JP2010538358A JP5812604B2 (en) | 2007-12-17 | 2007-12-17 | Continuously variable transmission with drive belt, method of operating continuously variable transmission, and method of manufacturing drive belt |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/EP2007/064037 WO2009076999A1 (en) | 2007-12-17 | 2007-12-17 | Continuously variable transmission incorporating a drive belt, method for operating it and method for manufacturing the drive belt |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2009076999A1 true WO2009076999A1 (en) | 2009-06-25 |
Family
ID=39712591
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2007/064037 WO2009076999A1 (en) | 2007-12-17 | 2007-12-17 | Continuously variable transmission incorporating a drive belt, method for operating it and method for manufacturing the drive belt |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP2235397A1 (en) |
JP (1) | JP5812604B2 (en) |
KR (1) | KR20100096249A (en) |
CN (1) | CN101903685B (en) |
WO (1) | WO2009076999A1 (en) |
Cited By (2)
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. |
WO2017108206A1 (en) * | 2015-12-22 | 2017-06-29 | Robert Bosch Gmbh | Transverse element for a drive belt, drive belt and method for manufacturing such a transverse element |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62196439A (en) * | 1986-02-21 | 1987-08-29 | Toyota Motor Corp | Belt type continuously variable transmission |
JPS62196444A (en) * | 1986-02-21 | 1987-08-29 | Toyota Motor Corp | Belt type continuously variable transmission |
WO1998020269A1 (en) * | 1996-11-05 | 1998-05-14 | Nissan Motor Co., Ltd. | Continuously variable transmission with lubricating apparatus |
DE10026223A1 (en) * | 1999-06-16 | 2001-01-25 | Luk Lamellen & Kupplungsbau | Determining operating life of fluid, especially gearbox oil, involves using algorithm relating variation in useful life to temperature in inverse proportion to rate of change in reaction rate |
EP1283379A2 (en) * | 2001-08-10 | 2003-02-12 | Honda Giken Kogyo Kabushiki Kaisha | Belt for continuously variable transmission |
WO2006062400A1 (en) * | 2004-12-08 | 2006-06-15 | Robert Bosch Gmbh | Drive belt for a transmission with convex pulley sheaves |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01234638A (en) * | 1988-03-14 | 1989-09-19 | Toyota Motor Corp | V-block for chain belt |
JPH01269761A (en) * | 1988-04-21 | 1989-10-27 | Mazda Motor Corp | Controller for belt type continuously variable transmission |
JP2973666B2 (en) * | 1991-12-03 | 1999-11-08 | トヨタ自動車株式会社 | Belt-type continuously variable transmission for vehicles |
JP3209323B2 (en) * | 1996-10-11 | 2001-09-17 | 日産自動車株式会社 | Plate element and belt for belt-type continuously variable transmission, and belt-type continuously variable transmission |
JP3737952B2 (en) * | 2001-02-16 | 2006-01-25 | 本田技研工業株式会社 | CVT belt push block and manufacturing method thereof |
JP3938897B2 (en) * | 2002-09-30 | 2007-06-27 | ジヤトコ株式会社 | Hydraulic control device for belt type continuously variable transmission |
JP4973972B2 (en) * | 2003-08-22 | 2012-07-11 | 日産自動車株式会社 | Low friction sliding member for continuously variable transmission and continuously variable transmission oil composition used therefor |
ATE475035T1 (en) * | 2005-11-08 | 2010-08-15 | Bosch Gmbh Robert | TRANSMISSION WITH PULLEYS AND DRIVE BELT |
-
2007
- 2007-12-17 EP EP07857668A patent/EP2235397A1/en not_active Withdrawn
- 2007-12-17 CN CN200780101958.8A patent/CN101903685B/en active Active
- 2007-12-17 WO PCT/EP2007/064037 patent/WO2009076999A1/en active Application Filing
- 2007-12-17 JP JP2010538358A patent/JP5812604B2/en active Active
- 2007-12-17 KR KR1020107015826A patent/KR20100096249A/en not_active Application Discontinuation
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62196439A (en) * | 1986-02-21 | 1987-08-29 | Toyota Motor Corp | Belt type continuously variable transmission |
JPS62196444A (en) * | 1986-02-21 | 1987-08-29 | Toyota Motor Corp | Belt type continuously variable transmission |
WO1998020269A1 (en) * | 1996-11-05 | 1998-05-14 | Nissan Motor Co., Ltd. | Continuously variable transmission with lubricating apparatus |
DE10026223A1 (en) * | 1999-06-16 | 2001-01-25 | Luk Lamellen & Kupplungsbau | Determining operating life of fluid, especially gearbox oil, involves using algorithm relating variation in useful life to temperature in inverse proportion to rate of change in reaction rate |
EP1283379A2 (en) * | 2001-08-10 | 2003-02-12 | Honda Giken Kogyo Kabushiki Kaisha | Belt for continuously variable transmission |
WO2006062400A1 (en) * | 2004-12-08 | 2006-06-15 | Robert Bosch Gmbh | Drive belt for a transmission with convex pulley sheaves |
Non-Patent Citations (1)
Title |
---|
See also references of EP2235397A1 * |
Cited By (5)
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. |
WO2010147458A1 (en) * | 2009-06-17 | 2010-12-23 | Robert Bosch Gmbh | Method for operating a continuously variable transmission incorporating a drive belt |
WO2017108206A1 (en) * | 2015-12-22 | 2017-06-29 | Robert Bosch Gmbh | Transverse element for a drive belt, drive belt and method for manufacturing such a transverse element |
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. |
CN108474448A (en) * | 2015-12-22 | 2018-08-31 | 罗伯特·博世有限公司 | For the lateral direction element of transmission belt, transmission belt and method for manufacturing this lateral direction element |
Also Published As
Publication number | Publication date |
---|---|
EP2235397A1 (en) | 2010-10-06 |
CN101903685B (en) | 2015-07-22 |
JP5812604B2 (en) | 2015-11-17 |
CN101903685A (en) | 2010-12-01 |
JP2011506885A (en) | 2011-03-03 |
KR20100096249A (en) | 2010-09-01 |
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