WO2011076397A1 - Courroie d'entraînement comprenant un anneau en acier - Google Patents

Courroie d'entraînement comprenant un anneau en acier Download PDF

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Publication number
WO2011076397A1
WO2011076397A1 PCT/EP2010/007858 EP2010007858W WO2011076397A1 WO 2011076397 A1 WO2011076397 A1 WO 2011076397A1 EP 2010007858 W EP2010007858 W EP 2010007858W WO 2011076397 A1 WO2011076397 A1 WO 2011076397A1
Authority
WO
WIPO (PCT)
Prior art keywords
ring
drive belt
thickness
surface layer
mass
Prior art date
Application number
PCT/EP2010/007858
Other languages
English (en)
Inventor
Bert Pennings
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 WO2011076397A1 publication Critical patent/WO2011076397A1/fr

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
    • 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
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/24—Nitriding
    • C23C8/26—Nitriding of ferrous surfaces

Definitions

  • the present invention relates to a drive belt for use in the well-known pulley- type continuously variable transmission or CVT that is typically applied in motor vehicles.
  • the drive belt is described in detail in EP 2 115 318 A and includes a multitude of plastic transverse segments that are each provided with at least one, but typically two recesses, each such recess accommodating only a single, flexible steel ring of the drive belt.
  • the transverse segments are also referred as transverse elements.
  • the transverse elements are either not fixed to the ring, in which case they can slide along the circumference thereof during operation in the CVT, or they are fixed to the ring by means of a elastomeric spacer provided there between, which spacer is typically in the form of a profiled rubber covering layer of the ring.
  • a ring is produced from maraging steel, which type of steel combines a comparatively favourable possibility to weld and plastically deform the material with the characteristics of great tensile strength and good resistance against both abrasive wear and bending and/or tensile stress fatigue, at least after the appropriate heat treatment thereof.
  • the known rings are provided with a fair hardness of the core material for realising the properties of good tensile, yield and bending strength combined with a high resistance against metal fatigue, which ring core is encased in a substantially harder, typically gas soft nitrided, and thus compressively stressed and hence fatigue-fracture resistant outer surface layer of the ring material.
  • This ring, its material specifications and its manufacturing method are well-known in relation to the application thereof in a particular type of drive belt that is known as the (Van Doorne) push belt that includes steel transverse elements and a number of said rings that are in this case mutually concentrically.
  • the (Van Doorne) push belt that includes steel transverse elements and a number of said rings that are in this case mutually concentrically.
  • many patent (application) documents on this topic exist, including for example EP-A-1 055 738, EP-A-1 176 224 A, JP-A-2000-337453 and the non pre-published international patent application PCT/NL2008/050259.
  • a thickness and hardness of the nitrided surface layer is to be carefully controlled in manufacturing to limit the internal ring stress and to provide the ring with a sufficient elasticity to allow longitudinal bending as well as resistance against fatigue fracture. Especially this latter feature is known to be a determining factor in the drive belt application of the rings, because of the numerous load and bending cycles it is subjected to during its service life.
  • the ring with a nitrided surface layer having a thickness of at least 20 % of the total ring thickness, as measured in the radial direction of the ring, and with a surface hardness of at least 800 HV0.1 (Vickers hardness with 100 gr. weight applied).
  • the thickness of the nitride layer is determined optically (with the aid of a microscope) on a polished and suitably etched cross-sectional surface of the ring.
  • the present invention departs from the above-described state of the art technology and aims to further increase the service life of the drive belt and/or to reduce the manufacturing cost thereof at least in combination with the present, specific type of drive belt.
  • such aim is realised by the drive belt incorporating the features of Claim 1 hereinafter. It was found that the manufacturing cost could be reduced significantly in this way, favourably without a detrimental effect on the fatigue strength of the drive belt. More in particular, it was found that the previously prescribed minimum nitrided surface layer thickness is not so much required for realising the desired fatigue strength of the ring as a separate component, but rather for the ring as incorporated in the drive belt, i.e. for limiting ring wear and thus the realising the desired fatigue strength of the drive belt as whole.
  • a maraging steel alloy taken form the range of alloys having a basic composition with 17 to 19 mass-% nickel, 4 to 6 mass-% molybdenum, 8 to 18 mass-% cobalt and with balance iron, possibly with some, i.e. less than 1 mass-%, titanium added and with less than 1 mass-% of inevitable contaminations
  • the optimum thickness of the nitride layer has been investigated.
  • a 200 pm thick ring is optimally provided with a nitride layer of between 5 and 15 pm thick, i.e. between 2.5 and 7.5% of the total, radial ring thickness, preferably combined with a surface hardness value of between 550 and 800 HV0.1.
  • the lower end of this range i.e. between 550 and 700 HV0.1 surface hardness, being preferred to minimise the wear of the plastic transverse elements in the frictional contact with the ring.
  • the hardness of the ring core material may be even less, i.e. below 500 HV1.0 (Vickers hardness with 1000 gr. weight applied).
  • Figure 1 provides a schematically depicted example of the well-known continuously variable transmission provided with a drive belt
  • Figure 2 is a cross-section of the known drive belt
  • Figure 3 figuratively represents the presently relevant part of the known manufacturing method of the ring component of the drive belt
  • Figure 4 is a schematic cross-section of the endless ring component of the drive belt in accordance with the invention.
  • Figure 1 shows the central parts of a known continuously variable transmission or CVT that is commonly applied in the drive line of motor vehicles between the engine and the drive wheels thereof.
  • the transmission comprises two pulleys 11 , 12, each provided with two conical pulley discs 15, where between a predominantly V-shaped pulley groove is defined and whereof one disc 15 is axially moveable relative to the other disc 15 of a respective pulley 11 , 12.
  • a drive belt 10 is wrapped around the pulleys 11 , 12 for transmitting a rotational movement and an accompanying torque from the one pulley 1 1 , 12 to the other 12, 11.
  • the transmission generally also comprises activation means that impose on the said at least one disc 15 an axially oriented clamping force Fax directed towards the respective other pulley disc 15 such that the drive belt 10 is clamped there between. Also, a (speed) ratio of the transmission between the rotational speed of a driven pulley 12 and the rotational speed of a driving pulley 11 is determined thereby.
  • FIG. 1 An example of a known drive belt 10 is shown in more detail figure 2 in a cross-section thereof, which drive belt 10 is shown to incorporate two endless rings 14.
  • the belt 10 further comprises a number of transverse segments or elements 13 (see also figure 1) that are held together by the rings 14 that are each located in a respective recess provided in the transverse elements 13.
  • the transverse elements 13 take-up the said clamping force exerted between the pulley discs 15, such when an input torque is exerted on a so-called driving pulley 11 , friction between the discs 15 and the drive belt 10, causes a rotation of that driving pulley 11 to be transferred to a so-called driven pulley 12 via the likewise rotating drive belt 10.
  • the drive belt 10 and in particular the rings 14 thereof are subjected to a cyclically varying tensile and bending stresses, i.e. a fatigue load.
  • a fatigue load i.e. the resistance against metal fatigue, i.e. the fatigue strength of the rings 14 thus determines the functional life span of the drive belt 10 at a given torque T to be transmitted thereby. Therefore, it has been a long standing general aim in the development of the drive belt manufacturing method to realise a required ring fatigue strength at a minimum combined material and processing cost.
  • Figure 3 illustrates a relevant part of the known manufacturing method for the drive belt ring component 14, wherein the separate process steps are indicated by way of Roman numerals.
  • a first process step I a thin sheet or plate 51 of base material that typically has a thickness in the range between 0.4 mm and 0.5 mm is bend into a cylindrical shape and the meeting plate ends 52 are welded together in a second process step II to form an open, hollow cylinder or tube 53.
  • a third step III of the process the tube 53 is annealed.
  • a fourth process step IV the tube 53 is cut into a number of annular hoops 54, which are subsequently -process step five V- rolled to reduce the thickness thereof to less than 0.250 mm, typically about 185 ⁇ , while being elongated.
  • the hoops 54 are usually referred to as rings 14.
  • the rings 14 are then subjected to a further or ring annealing process step VI for removing the work hardening effect of the previous rolling process (i.e. step five V) by recovery and recristalisation of the ring material at a temperature considerably above 600 degree Celsius, e.g. about 800 degree Celsius.
  • the rings 14 are calibrated, i.e.
  • the rings 14 are heat-treated in two consecutive process steps, namely an eighth process step VIII of ageing or bulk precipitation hardening and a ninth process step IX of nitriding or case hardening, which eight and ninth process steps VIII, IX may be combined into one, i.e. may be performed simultaneously. More in particular, both such heat-treatments involve heating the rings 14 in an industrial oven or furnace containing a controlled gas atmosphere that typically is composed of nitrogen and some, e.g.
  • Figure 4 represents a greatly enlarged, schematically drawn cross-section of the known ring 14 including an indication therein of a case hardened, in this case nitrided surface layer 20 in accordance with the present invention.
  • Figure 4 illustrates the feature of the nitrided surface layer 20 (by the darker grey tone) of the rings 14 thereof and its thickness relative to the total radial thickness of the rings 14.
  • the thickness T of the nitrided surface layer 20 of the ring 14 amounts to 7.5% of its total thickness D, whereby the optimum fatigue properties for the ring 14 are achieved at least for its application in the drive belt 10 comprising plastic transverse elements 13 with one or more recesses wherein only one such ring 14 is located each time.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Transmissions By Endless Flexible Members (AREA)
  • Heat Treatment Of Articles (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)

Abstract

La présente invention se rapporte à une courroie d'entraînement (10) comprenant une pluralité de segments transversaux en plastique (13). Chacun desdits segments transversaux comporte au moins un renfoncement, mais plutôt deux renfoncements en règle générale. Selon l'invention, chacun desdits renfoncements reçoit uniquement un seul anneau en acier souple (14) de la courroie d'entraînement (10). L'anneau (14) peut être totalement dépourvu d'une couche de surface nitrurée ou bien il peut être pourvu d'une couche de surface nitrurée (20) dont l'épaisseur varie entre 2,5 % et 7,5 % de l'épaisseur totale de l'anneau (14) lorsqu'elle est mesurée dans le sens radial de ce dernier.
PCT/EP2010/007858 2009-12-23 2010-12-22 Courroie d'entraînement comprenant un anneau en acier WO2011076397A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL1037583A NL1037583C2 (en) 2009-12-23 2009-12-23 Drive belt provided with a steel ring.
NL1037583 2009-12-23

Publications (1)

Publication Number Publication Date
WO2011076397A1 true WO2011076397A1 (fr) 2011-06-30

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Family Applications (1)

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PCT/EP2010/007858 WO2011076397A1 (fr) 2009-12-23 2010-12-22 Courroie d'entraînement comprenant un anneau en acier

Country Status (2)

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NL (1) NL1037583C2 (fr)
WO (1) WO2011076397A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1039261C2 (en) * 2011-12-23 2013-06-26 Bosch Gmbh Robert Flexible steel ring and drive belt provided with a laminated set of such rings.
NL1040566C2 (en) * 2013-12-24 2015-06-26 Bosch Gmbh Robert Method for manufacturing a carrier ring suitable for use in a drive belt for a continuously variable transmission.
JP2016505092A (ja) * 2012-12-24 2016-02-18 ローベルト ボツシユ ゲゼルシヤフト ミツト ベシユレンクテル ハフツングＲｏｂｅｒｔ Ｂｏｓｃｈ Ｇｍｂｈ 駆動ベルト用リングセットの製造方法における熱処理プロセス
WO2016096156A1 (fr) * 2014-12-17 2016-06-23 Robert Bosch Gmbh Bague souple en acier pour une courroie d'entraînement pour une transmission à variation continue et son procédé de fabrication

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4541822A (en) * 1983-12-19 1985-09-17 Dayco Corporation Belt construction, transverse belt element therefor and method of making the same
US4612005A (en) * 1982-10-25 1986-09-16 Dayco Corporation Transverse belt elements for a belt construction
US4698050A (en) * 1985-05-18 1987-10-06 Honda Giken Kogyo, K.K. Laminated metallic belt for torque transmission device and method of manufacture thereof
EP1055738A2 (fr) 1999-05-28 2000-11-29 Honda Giken Kogyo Kabushiki Kaisha Procédé de fabrication des anneaux laminés et dispositif de traitment thermique utilisé dans ce procédé
JP2000337453A (ja) 1999-05-31 2000-12-05 Honda Motor Co Ltd 無端状金属ベルトの製造方法
EP1176224A1 (fr) 2000-07-24 2002-01-30 Nissan Motor Co., Ltd. Acier maraging nitruré et procédé pour sa fabrication
WO2008094035A2 (fr) * 2007-01-31 2008-08-07 Robert Bosch Gmbh Courroie d'entraînement

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3439132B2 (ja) * 1998-09-10 2003-08-25 エア・ウォーター株式会社 マルエージング鋼の窒化方法およびそれによって得られたマルエージング鋼製品

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4612005A (en) * 1982-10-25 1986-09-16 Dayco Corporation Transverse belt elements for a belt construction
US4541822A (en) * 1983-12-19 1985-09-17 Dayco Corporation Belt construction, transverse belt element therefor and method of making the same
US4698050A (en) * 1985-05-18 1987-10-06 Honda Giken Kogyo, K.K. Laminated metallic belt for torque transmission device and method of manufacture thereof
EP1055738A2 (fr) 1999-05-28 2000-11-29 Honda Giken Kogyo Kabushiki Kaisha Procédé de fabrication des anneaux laminés et dispositif de traitment thermique utilisé dans ce procédé
JP2000337453A (ja) 1999-05-31 2000-12-05 Honda Motor Co Ltd 無端状金属ベルトの製造方法
EP1176224A1 (fr) 2000-07-24 2002-01-30 Nissan Motor Co., Ltd. Acier maraging nitruré et procédé pour sa fabrication
WO2008094035A2 (fr) * 2007-01-31 2008-08-07 Robert Bosch Gmbh Courroie d'entraînement
EP2115318A2 (fr) 2007-01-31 2009-11-11 Robert Bosch GmbH Courroie d'entraînement

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL1039261C2 (en) * 2011-12-23 2013-06-26 Bosch Gmbh Robert Flexible steel ring and drive belt provided with a laminated set of such rings.
WO2013095089A1 (fr) * 2011-12-23 2013-06-27 Robert Bosch Gmbh Bague d'acier souple et courroie d'entraînement comportant un ensemble stratifié de telles bagues
JP2016505092A (ja) * 2012-12-24 2016-02-18 ローベルト ボツシユ ゲゼルシヤフト ミツト ベシユレンクテル ハフツングＲｏｂｅｒｔ Ｂｏｓｃｈ Ｇｍｂｈ 駆動ベルト用リングセットの製造方法における熱処理プロセス
NL1040566C2 (en) * 2013-12-24 2015-06-26 Bosch Gmbh Robert Method for manufacturing a carrier ring suitable for use in a drive belt for a continuously variable transmission.
WO2015097296A1 (fr) * 2013-12-24 2015-07-02 Robert Bosch Gmbh Procédé de fabrication d'un anneau de support adapté à une utilisation dans une courroie de transmission pour une transmission à variation continue
WO2016096156A1 (fr) * 2014-12-17 2016-06-23 Robert Bosch Gmbh Bague souple en acier pour une courroie d'entraînement pour une transmission à variation continue et son procédé de fabrication
NL1041102B1 (en) * 2014-12-17 2016-10-11 Bosch Gmbh Robert Flexible steel ring for a drive belt for a continuously variable transmission and method for producing such.
JP2018506640A (ja) * 2014-12-17 2018-03-08 ローベルト ボツシユ ゲゼルシヤフト ミツト ベシユレンクテル ハフツングＲｏｂｅｒｔ Ｂｏｓｃｈ Ｇｍｂｈ 無段変速機用の駆動ベルト用のフレキシブルな鋼リングおよびこのような鋼リングを製造する方法

Also Published As

Publication number Publication date
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