WO2005090823A1 - Belt for a continuously variable transmission - Google Patents

Belt for a continuously variable transmission Download PDF

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Publication number
WO2005090823A1
WO2005090823A1 PCT/EP2005/051278 EP2005051278W WO2005090823A1 WO 2005090823 A1 WO2005090823 A1 WO 2005090823A1 EP 2005051278 W EP2005051278 W EP 2005051278W WO 2005090823 A1 WO2005090823 A1 WO 2005090823A1
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WO
WIPO (PCT)
Prior art keywords
external
friction
belt
friction blocks
internal
Prior art date
Application number
PCT/EP2005/051278
Other languages
French (fr)
Inventor
Sergio Lolli
Giuseppe Costa
Original Assignee
Dayco Europe S.R.L. Con Unico Socio
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 Dayco Europe S.R.L. Con Unico Socio filed Critical Dayco Europe S.R.L. Con Unico Socio
Publication of WO2005090823A1 publication Critical patent/WO2005090823A1/en

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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
    • F16G5/166—V-belts, i.e. belts of tapered cross-section consisting of several parts with non-metallic rings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
    • B29D29/00—Producing belts or bands
    • B29D29/10—Driving belts having wedge-shaped cross-section

Definitions

  • the present invention concerns a belt for continuously variable transmissions.
  • continuously variable transmissions ⁇ CVT continuously variable transmissions
  • speed variators use belts with a substantially trapezoidal section, which are provided with lateral friction surfaces suited to cooperate with respective sides of pulleys with a trapezoidal race.
  • the variation of the transmission ratio occurs by modifying the width of the pulley race and, consequently, the belt winding diameter with mechanisms of a known type.
  • speed variators are used to transmit relatively limited powers and they use belts having a body made of elastomer material and provided with a longitudinal internal reinforcement suited to give the belt the necessary mechanical resistance to tensile stress.
  • the body of elastomer material is normally provided with at least one toothing able to give the respective belt a good flexibility and, therefore, the ability to work with relatively small winding diameters, while still maintaining a sufficiently large lateral surface.
  • speed variators have been developed that are suited to transmit a relatively high power.
  • EP1106865 illustrates a belt for variators suited to transmit relatively high powers comprising a continuous annular band having a body of elastomer material internally reinforced with a longitudinal reinforcement and a series of transverse blocks of plastic material jointly moulded on the continuous band.
  • the continuous band is provided on the outside with at least one toothing presenting a series of uniformly distributed coupling teeth.
  • Each of the blocks presents a longitudinal section with a substantially rhomboidal shape.
  • the belt described above presents the inconvenience that, in use, the transverse blocks are subjected to torques in the longitudinal direction during the phase of disengagement from the pulleys of the variator, causing harmful vibration for the duration of the belt.
  • the aim of the present invention is to realise a belt for a continuously variable transmission free from the inconveniences described above.
  • a belt for a continuously variable transmission is realised, as defined in claim 1.
  • FIG. 1 is a partial side view of a belt realised according to the present invention.
  • - figure 2 is an enlarged section of a length of the belt in figure 1;
  • - figure 3 is an axonometric view of a length of the belt in figure 1;
  • - figure 4 is an axonometric view of a component of the belt according to a second embodiment of the present invention
  • - figure 5 schematically represents a first step of a method for producing a belt according to the present invention
  • figure 6 schematically represents a second step of the production method in figure 5;
  • FIG. 7 schematically represents a step of a second method for producing a belt according to the present invention.
  • the belt 1 indicates the whole of a belt for a continuously variable transmission (CVT) .
  • the belt 1 essentially comprises a. continuous band 2 having the aim of transmitting the load, and a plurality of friction blocks 3, anchored to the continuous band 2 in a position spaced one from the other, having the aim of cooperating by friction by means of respective lateral sides 4 with transmission pulleys (illustrated with hatching) with a trapezoidal race, of a known type.
  • the continuous band 2 presents a closed annular profile and essentially comprises a body 5, and a plurality of substantially inextensible, filiform inserts 8, sunk in the body 5.
  • the inserts 8 extend longitudinally and parallel to each other along the body 5, they are realised by means of a conventional spiral-winding technique and may be composed of glass or aramidic fibres, for example of the type known by the trade name Kevlar®.
  • the body 5, of elastomer material, for example HNBR, is provided with an internal back 9 fa_cing towards the inside of the spirals of the inserts 8 and of an external back 11 opposite the internal back 9 with respect to the inserts 8, both presenting transversely respective series of hollows 10 and teeth 12 uniformly distributed on the respective backs.
  • the hollows 10 are grouped in pairs and each pair of hollows 10 of the internal back 9 relates to a tooth 12 of the eternal back 11 and each tooth 12 is located in a mid point of the relative pair of hollows 10.
  • each hollow 10 has a substantially circular profile and each tooth 12 has a profile 13 elongated in a radial direction outwardly with respect to the centre of the spirals of the inserts 8, for example it presents a parabolic trend.
  • the friction blocks 3 are made of plastic material and, according to the present invention, they are jointly moulded on the body 5 in such a way as to surround it completely and each incorporate a tooth 12 and a corresponding pair of hollows 10.
  • Each block 3 is separate from the others, has a substantially trapezoidal shape (figure 3) , and has a through central cavity 21 engaged by the continuous band 2 that are shape coupled; in particular, the cavity 21 of each block 3 presents on the side facing the internal back 9 a pair of transverse ridges 22 having a section with an arched circumference so as to reproduce, in the negative, the shape of a corresponding pair of hollows 10 of the continuous band 2.
  • each central cavity 21 is also delimited by a coupling portion 28 of the friction block 3, situated close to the continuous band 2 and defining a recess 23 the shape of which reproduces, in the negative, the shape of a corresponding tooth 12 of the continuous band 2.
  • each block 3 is conveniently defined by respective convex surfaces in the longitudinal direction, converging one another towards the inside of the belt 1; the convex shape of the above-mentioned surfaces facilitates the self-alignment of the blocks 3 in the phase of engagement with the pulleys .
  • Each block 3 integrally presents an internal wedge 24 extending towards the inside of the spiral winding of the inserts 8 starting from the internal back 9, and an external wedge 25 opposite the internal wedge 24 with respect to the body 5.
  • the internal wedge 24 is delimited in a longitudinal direction by a pair of surfaces 26 converging on each other towards the inside of the spiral winding of the inserts 8, and therefore presents in the longitudinal section a tapered shape necessary to allow small winding diameters of the belt 1 (figure 1) without interference between adjacent blocks 3.
  • the external wedge 25 of each block 3 is tapered, that is delimited in a longitudinal direction by a pair of surfaces 27 converging on each other in a direction opposite the surfaces 26.
  • each block 3 presents, on its respective opposite bands, a pair of stopping ridges 30 in relief with respect to the respective surfaces 27 and situated at an external radial end 28 of the external wedge 25.
  • Each stopping ridge 30 presents a width smaller than that of the respective external wedge 25, and it presents a flat contact surface 31, perpendicular to the filiform, inserts 8 and in relief from the respective surface 27 in such a way that, when two adjacent blocks 4 follow a path along a rectilinear direction, for example they follow a rectilinear branch of the continuously variable transmission located between two pulleys, the respective facing contact surfaces 31 come in contact and tend to keep the block 4 substantially stable 4.
  • the procedure for making the belt 1 essentially consists of a first step of realising the continuous band 2 by means of known techniques used in the manufacture of toothed belts and a subsequent step of positioning the continuous band 2 in a mould 34 having a circular seat 35 (in figure 7 the circular seat is occupied by the continuous band 2) surrounded respectively on the outside and on the inside by a plurality of external 36 and internal compartments 37.
  • the external 36 and internal compartments 37 have a corresponding shape and a number equal to the blocks 3 of the belt 1 and are arranged in such a way that a pair of hollows 10 and the relative tooth 12 are enclosed respectively by an internal compartment 37 and by an external compartment 36.
  • the manufacturing procedure also comprises a further step of joint moulding in which the plastic material which forms the blocks 3 is injected in the above-mentioned external 36 and internal compartments 37.
  • the external 36 and internal compartments 37 are defined by respective external 38 and internal radial septums 39 which also radially delimit the circular seat 35.
  • the external 36 and internal compartments 37 reproduce in the negative the profile of the internal 24 and external wedges 25 and are shaped so as to define the contact surface 31 so that the contact surfaces 31 of a first block 3 comes in contact with a second block 3 adjacent to the first when the above- mentioned two blocks 3 follow a path along a rectilinear direction, for example they follow a rectilinear branch of the continuously variable transmission located between two pulleys .
  • a second mould 33 comprises (figure 5) the circular seat 35, the internal compartments 37 and an annular cavity 48 adjacent to the circular seat 35 and opposite the internal compartments 37 with respect to the circular seat 35.
  • the mould 33 defines a rigid structure 49 integral with the continuous band 2 by means of the presence of the teeth 12 and of the hollows 10 and comprising a rim 50 defined by the annular cavity 48 and a series of internal wedges 24 rigidly connected to the rim 50 itself and defined by the internal compartments 37.
  • the rigid structure 49 is divided by means of a cutting tool 51 suitably shaped to cut the contact surface 31 and separate the friction blocks 3, each corresponding to a pair of hollows 10 and to a tooth 12.
  • the belt 1 connects two p»ulleys (not illustrated) of a continuously variable transmission thus defining a taut branch and a loose branch of the transmi-ssion located between the two pulleys .
  • the belt is fitted into a trapezoidal race of the above- mentioned pulleys so that the lateral sides 4 cooperate by friction on walls carried by the pulleys and delimiting the trapezoidal race, thus allowing power to be transferred to a driven part.
  • Figure 4 illustrates a second embodiment of a friction block 40 for a belt according to a further embodiment of the present invention, which is described below only in so far as it differs from the belt 1, indicating its components, where possible, with the same reference numbers used to distinguish similar or corresponding parts of the block 3.
  • the block 40 comprises stopping caps 41 presenting a ' U' shape and comprising a first and a second flat vertical lateral wall 42, 43 and a horizontal covering element 44.
  • the first and the second lateral wall 42, 43 are rigidly connected at the top to the covering element 44 delimiting a hollow 45 and they have the respective flat contact surfaces 31 on opposite parts with respect to the hollow 45.
  • the stopping caps 41 are then inserted on the external wedge 25 of the respective friction blocks 3 by means of the hollow 45 and are rigidly fixed in a known way, for example by gluing or by ultrasound welding.
  • the fact that the stopping elements 30, 41 are held integrally by the respective external wedges 25 of the friction blocks 3 allows the resistant section of the coupling portions 28 of the friction blocks 3 to be increased and consequently to transmit high powers .
  • stopping elements 30, 41 are located at the end of the external wedge 25 opposite the continuous band 2 allows maximisation of the respective effects of the relative longitudinal stresses between the blocks 3 and maximisation of the resistant section of the block 3.
  • the integral stopping ridges 30 are reliable and may allow reduction of production times .
  • removable stopping caps 41 makes it possible, where suitable, to have a different choice of materials to use for the stopping cap 41 itself and for the friction block 3 and allows facilitation of the geometry of the mould 34, in particular of the external 38 and internal radial septums 39.
  • the characteristics of the coupling between the friction blocks 3, 40 and the continuous band 2 may be improved by adding an adhesive material, for example CHEMOSIL (Henkel registered trade mark) or CHEMLOK (Lord registered trade mark) , to be applied in the interface area between the walls of the central cavity 21 and the internal back 9 and the external back 10 of the continuous band 2.
  • an adhesive material for example CHEMOSIL (Henkel registered trade mark) or CHEMLOK (Lord registered trade mark)

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

Abstract

Belt (1) for a continuously variable transmission, comprising a continuous annular band (2) presenting a body (5) of elastomer material reinforced on the inside with a substantially longitudinal reinforcement (8), an external back (11) presenting a series of uniformly distributed teeth (12), and an internal back (9) opposite the external back (11) with respect to the reinforcement (8). The belt (1) also comprises a plurality of friction blocks (3) of plastic material, each of which is jointly moulded on the continuous annular band (2) so as to occupy at least one of the teeth (12); each of the friction blocks (3) comprises integrally an internal Wedge (24) and an external wedge (25) respectively in relief with respect to the internal back (9) and to the external back (11), and it also presents lateral sides (4) suited to cooperate by friction with a pulley of the transmission. A first friction block (3) holds a stopping element (30, 41) integral with said external wedge (25) and cooperating in contact against a second friction block (3) adjacent to the first when the adjacent friction blocks (3) follow a path along a substantially rectilinear working direction.

Description

BELT FOR A CONTINUOUSLY VARIABLE TRANSMISSION
TECHNICAL FIELD
The present invention concerns a belt for continuously variable transmissions.
BACKGROUND ART
As is known, continuously variable transmissions <CVT) , or speed variators, use belts with a substantially trapezoidal section, which are provided with lateral friction surfaces suited to cooperate with respective sides of pulleys with a trapezoidal race. The variation of the transmission ratio occurs by modifying the width of the pulley race and, consequently, the belt winding diameter with mechanisms of a known type.
Generally, speed variators are used to transmit relatively limited powers and they use belts having a body made of elastomer material and provided with a longitudinal internal reinforcement suited to give the belt the necessary mechanical resistance to tensile stress. The body of elastomer material is normally provided with at least one toothing able to give the respective belt a good flexibility and, therefore, the ability to work with relatively small winding diameters, while still maintaining a sufficiently large lateral surface. Recently, speed variators have been developed that are suited to transmit a relatively high power.
The application for a European patent EP1106865 illustrates a belt for variators suited to transmit relatively high powers comprising a continuous annular band having a body of elastomer material internally reinforced with a longitudinal reinforcement and a series of transverse blocks of plastic material jointly moulded on the continuous band.
In particular, the continuous band is provided on the outside with at least one toothing presenting a series of uniformly distributed coupling teeth. Each of the blocks presents a longitudinal section with a substantially rhomboidal shape.
The belt described above presents the inconvenience that, in use, the transverse blocks are subjected to torques in the longitudinal direction during the phase of disengagement from the pulleys of the variator, causing harmful vibration for the duration of the belt.
The application for an international patent O03031841 describes a belt similar to the previous one in which every transverse block is equipped with an integral friction shell presenting a pair of lateral sides suited to cooperate by friction with a pulley of a speed variator, and a pair of contact surfaces perpendicular to the direction of operation of the belt. In use, when a block is disengaged from the pulley of the variator, the contact surface of a shell comes in contact with the contact surface of the next shell, avoiding longitudinal stresses.
However, it is difficult to assess the size of the thickness of the friction shells because a thickness sufficient to bear the shear forces transmitted by the pulley makes the resistant section of the transverse block near the coupling tooth of the continuous band too thin, causing a possible yielding of the transverse block. Besides, an adequate resistant section of the transverse block would require a reduced shell thickness, causing breakage of tlie lateral sides .
DISCLOSURE OF INVENTION
The aim of the present invention is to realise a belt for a continuously variable transmission free from the inconveniences described above.
According to the present invention a belt for a continuously variable transmission is realised, as defined in claim 1. BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention a preferred embodiment is now described, purely as an example without limitation, with reference to the enclosed drawings in which:
- figure 1 is a partial side view of a belt realised according to the present invention;
- figure 2 is an enlarged section of a length of the belt in figure 1; - figure 3 is an axonometric view of a length of the belt in figure 1;
- figure 4 is an axonometric view of a component of the belt according to a second embodiment of the present invention; - figure 5 schematically represents a first step of a method for producing a belt according to the present invention;
- figure 6 schematically represents a second step of the production method in figure 5; and
- figure 7 schematically represents a step of a second method for producing a belt according to the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
With reference to the drawings, the number 1 indicates the whole of a belt for a continuously variable transmission (CVT) . The belt 1 essentially comprises a. continuous band 2 having the aim of transmitting the load, and a plurality of friction blocks 3, anchored to the continuous band 2 in a position spaced one from the other, having the aim of cooperating by friction by means of respective lateral sides 4 with transmission pulleys (illustrated with hatching) with a trapezoidal race, of a known type.
In particular, the continuous band 2 presents a closed annular profile and essentially comprises a body 5, and a plurality of substantially inextensible, filiform inserts 8, sunk in the body 5.
The inserts 8 extend longitudinally and parallel to each other along the body 5, they are realised by means of a conventional spiral-winding technique and may be composed of glass or aramidic fibres, for example of the type known by the trade name Kevlar®.
The body 5, of elastomer material, for example HNBR, is provided with an internal back 9 fa_cing towards the inside of the spirals of the inserts 8 and of an external back 11 opposite the internal back 9 with respect to the inserts 8, both presenting transversely respective series of hollows 10 and teeth 12 uniformly distributed on the respective backs. The hollows 10 are grouped in pairs and each pair of hollows 10 of the internal back 9 relates to a tooth 12 of the eternal back 11 and each tooth 12 is located in a mid point of the relative pair of hollows 10.
Conveniently (figure 2) , each hollow 10 has a substantially circular profile and each tooth 12 has a profile 13 elongated in a radial direction outwardly with respect to the centre of the spirals of the inserts 8, for example it presents a parabolic trend.
The friction blocks 3 are made of plastic material and, according to the present invention, they are jointly moulded on the body 5 in such a way as to surround it completely and each incorporate a tooth 12 and a corresponding pair of hollows 10.
Each block 3 is separate from the others, has a substantially trapezoidal shape (figure 3) , and has a through central cavity 21 engaged by the continuous band 2 that are shape coupled; in particular, the cavity 21 of each block 3 presents on the side facing the internal back 9 a pair of transverse ridges 22 having a section with an arched circumference so as to reproduce, in the negative, the shape of a corresponding pair of hollows 10 of the continuous band 2. On the side facing the external back 11, each central cavity 21 is also delimited by a coupling portion 28 of the friction block 3, situated close to the continuous band 2 and defining a recess 23 the shape of which reproduces, in the negative, the shape of a corresponding tooth 12 of the continuous band 2.
The lateral sides 4 of each block 3 are conveniently defined by respective convex surfaces in the longitudinal direction, converging one another towards the inside of the belt 1; the convex shape of the above-mentioned surfaces facilitates the self-alignment of the blocks 3 in the phase of engagement with the pulleys .
Each block 3 integrally presents an internal wedge 24 extending towards the inside of the spiral winding of the inserts 8 starting from the internal back 9, and an external wedge 25 opposite the internal wedge 24 with respect to the body 5. The internal wedge 24 is delimited in a longitudinal direction by a pair of surfaces 26 converging on each other towards the inside of the spiral winding of the inserts 8, and therefore presents in the longitudinal section a tapered shape necessary to allow small winding diameters of the belt 1 (figure 1) without interference between adjacent blocks 3. Conveniently, also the external wedge 25 of each block 3 is tapered, that is delimited in a longitudinal direction by a pair of surfaces 27 converging on each other in a direction opposite the surfaces 26.
The external wedge 25 of each block 3 presents, on its respective opposite bands, a pair of stopping ridges 30 in relief with respect to the respective surfaces 27 and situated at an external radial end 28 of the external wedge 25.
Each stopping ridge 30 presents a width smaller than that of the respective external wedge 25, and it presents a flat contact surface 31, perpendicular to the filiform, inserts 8 and in relief from the respective surface 27 in such a way that, when two adjacent blocks 4 follow a path along a rectilinear direction, for example they follow a rectilinear branch of the continuously variable transmission located between two pulleys, the respective facing contact surfaces 31 come in contact and tend to keep the block 4 substantially stable 4.
The procedure for making the belt 1 essentially consists of a first step of realising the continuous band 2 by means of known techniques used in the manufacture of toothed belts and a subsequent step of positioning the continuous band 2 in a mould 34 having a circular seat 35 (in figure 7 the circular seat is occupied by the continuous band 2) surrounded respectively on the outside and on the inside by a plurality of external 36 and internal compartments 37. The external 36 and internal compartments 37 have a corresponding shape and a number equal to the blocks 3 of the belt 1 and are arranged in such a way that a pair of hollows 10 and the relative tooth 12 are enclosed respectively by an internal compartment 37 and by an external compartment 36.
The manufacturing procedure also comprises a further step of joint moulding in which the plastic material which forms the blocks 3 is injected in the above-mentioned external 36 and internal compartments 37.
In particular, the external 36 and internal compartments 37 are defined by respective external 38 and internal radial septums 39 which also radially delimit the circular seat 35. The external 36 and internal compartments 37 reproduce in the negative the profile of the internal 24 and external wedges 25 and are shaped so as to define the contact surface 31 so that the contact surfaces 31 of a first block 3 comes in contact with a second block 3 adjacent to the first when the above- mentioned two blocks 3 follow a path along a rectilinear direction, for example they follow a rectilinear branch of the continuously variable transmission located between two pulleys .
According to a variation of the manufacturing procedure illustrated above, a second mould 33 comprises (figure 5) the circular seat 35, the internal compartments 37 and an annular cavity 48 adjacent to the circular seat 35 and opposite the internal compartments 37 with respect to the circular seat 35.
The mould 33 defines a rigid structure 49 integral with the continuous band 2 by means of the presence of the teeth 12 and of the hollows 10 and comprising a rim 50 defined by the annular cavity 48 and a series of internal wedges 24 rigidly connected to the rim 50 itself and defined by the internal compartments 37.
Later (figure 6) the rigid structure 49 is divided by means of a cutting tool 51 suitably shaped to cut the contact surface 31 and separate the friction blocks 3, each corresponding to a pair of hollows 10 and to a tooth 12.
In use, the belt 1 connects two p»ulleys (not illustrated) of a continuously variable transmission thus defining a taut branch and a loose branch of the transmi-ssion located between the two pulleys .
The belt is fitted into a trapezoidal race of the above- mentioned pulleys so that the lateral sides 4 cooperate by friction on walls carried by the pulleys and delimiting the trapezoidal race, thus allowing power to be transferred to a driven part.
Along the taut and loose branches of the transmission, two external wedges 25 of adjacent friction blocks 3 are in contact against the contact surfaces 31 of the respective stopping ridges 30 while the respective internal wedges 24 are separate.
On the contrary, when the above-mentioned external wedges 25 are wound around the pulleys, they are no longer in contact and the respective internal wedges 24 can come in contact when the minimum winding diameter is followed.
Figure 4 illustrates a second embodiment of a friction block 40 for a belt according to a further embodiment of the present invention, which is described below only in so far as it differs from the belt 1, indicating its components, where possible, with the same reference numbers used to distinguish similar or corresponding parts of the block 3. In particular, the block 40 comprises stopping caps 41 presenting a ' U' shape and comprising a first and a second flat vertical lateral wall 42, 43 and a horizontal covering element 44. The first and the second lateral wall 42, 43 are rigidly connected at the top to the covering element 44 delimiting a hollow 45 and they have the respective flat contact surfaces 31 on opposite parts with respect to the hollow 45.
The stopping caps 41 are then inserted on the external wedge 25 of the respective friction blocks 3 by means of the hollow 45 and are rigidly fixed in a known way, for example by gluing or by ultrasound welding.
The operation of a belt with friction blocks 40 is quite similar to that of the belt 1.
From an examination of the characteristics of the belt for a continuously variable transmission realised according to the present invention, the advantages that it allows to be obtained are clear.
In particular, the fact that the stopping elements 30, 41 are held integrally by the respective external wedges 25 of the friction blocks 3 allows the resistant section of the coupling portions 28 of the friction blocks 3 to be increased and consequently to transmit high powers .
The fact that the stopping elements 30, 41 are located at the end of the external wedge 25 opposite the continuous band 2 allows maximisation of the respective effects of the relative longitudinal stresses between the blocks 3 and maximisation of the resistant section of the block 3.
The integral stopping ridges 30 are reliable and may allow reduction of production times .
The realisation of removable stopping caps 41 makes it possible, where suitable, to have a different choice of materials to use for the stopping cap 41 itself and for the friction block 3 and allows facilitation of the geometry of the mould 34, in particular of the external 38 and internal radial septums 39.
The use of flat contact surfaces 31 allows simplification of the mould shape, avoiding undercuts and consequently tending to reduce the production costs.
Lastly it is clear that modification s and variations may be made to the belt for a continuousLy variable transmission described and illustrated herein without leaving the protective field of the present invention, as defined in the enclosed claims .
In particular, the characteristics of the coupling between the friction blocks 3, 40 and the continuous band 2 may be improved by adding an adhesive material, for example CHEMOSIL (Henkel registered trade mark) or CHEMLOK (Lord registered trade mark) , to be applied in the interface area between the walls of the central cavity 21 and the internal back 9 and the external back 10 of the continuous band 2.

Claims

C L A I S
1. Belt (1) for a continuously variable transmission, comprising a continuous annular band (2) having a body (5) of elastomer material reinforced on the inside with a substantially longitudinal reinforcement (8) , an external back
(11) presenting a series of uniformly dist-eributed teeth (12) , and an internal back (9) opposite said external back (11) with respect to said reinforcement (8) , sai-d belt (1) also comprising a plurality of friction blocks (3, 40) of plastic material, each of which is jointly moulded on said continuous annular band (2) so as to occupy at least one of said teeth
(12) , each of said friction blocks (3, 40) comprising integrally an internal wedge (24) and an external wedge (25) respectively in relief with respect to said internal back (9) and to said external back (11) , and also presenting lateral sides (4) suited to cooperate by friction, with a pulley of said transmission, said belt (1) being characterised in that each of said friction blocks (3, 40) holds a stopping element (30, 41) integral with said external wedge (25) , said stopping element (30, 41) of a first friction block cooperating in contact against a second friction block (3, 40) adjacent to said first friction block (3, 40) when sai-d first and second friction blocks (3, 40) follow a path along a substantially rectilinear working direction. 2) Belt according to claim 1, characterised in that said stopping elements (30, 41) are situated at an external radial end (28) of said external wedge (25) opposite said continuous band (2) .
3) Belt according to one of the claims 1 or 2, characterised in that said internal back (9) is provided with a series of uniformly distributed hollows (10) and that each of said friction blocks (3) is jointly moulded on said continuous annular band (2) so as to occupy two adjacent of said hollows (10) and one of said teeth (12) between two said adjacent hollows (10) .
4) Belt according to any one of the previous claims, characterised in that said angular stopping elements (30, 41) have a flat contact surface (31) substantially perpendicular to said reinforcement (8) .
5) Belt according to any one of the claims from 1 to 4, characterised in that said angular stopping elements (30) are integral with the respective friction blocks (3) .
6) Belt according to any one of the claims from 1 to 4, characterised in that said angular stopping elements (41) may be fitted on the respective friction blocks (40) . 7) Belt according to any one of the previous claims, characterised in that said friction blocks (3, 40) present respective through central cavities (21) coupling with said continuous band (2) and that between said continuous band (2) and said friction blocks (3, 40) , inside respective said through cavities (21) an adhesive material is applied.
8) Method for producing a belt (1) for a continuously variable transmission, said belt (1) comprising a continuous annular band (2) and friction blocks (3, 40), characterised in that it comprises the following steps :
- realising said continuous annular band (2) having a body (5) of elastomer material reinforced on the inside with a substantially longitudinal reinforcement (8) , an external back (11) presenting a series of uniformly distributed teeth (12) , and an internal back (9) opposite said external back (11) with respect to said reinforcement (8);
- with a mould (34) carrying out the joint moulding on said continuous band (2) of a rigid structure (49) integral with said continuous band (2), said mould (34) presenting a circular seat (35) housing said continuous band (2) , a plurality of internal compartments (37) internally adjacent to said circular seat (35) , and an annular cavity (48) externally adjacent to said circular seat (35) , said rigid structure (49) comprising a rim (50) defined by said continuous annular cavity (48) and external to said continuous band (2) and a series of internal wedges (24) defined by said internal compartments (37) and integral with said continuous band (2) and with said rim (50) ; - by means of cutting processes (51) subdividing said rim (50) into external wedges (25) facing said external back (11) , forming said friction blocks (3, 40) suited to cooperate with a pulley of a continuously variable transmission and integrally comprising the respective said internal (24) and external wedges (25) , each of said friction blocks (3, 40) being integral with said continuous band (2) and said cutting tools (51) being shaped in such a way as to define on each of said friction blocks (3, 40) a contact surface (31), located on the respective said external wedge (2), said contact surface (31) of a first friction block (3, 40) cooperating in contact with a second friction block (3, 40) adjacent to said first friction block (3, 40) when said first and second friction blocks (3, 40) follow a path along a substantially rectilinear working direction.
9) Method for producing a belt for a continuously variable transmission, said belt comprising a continuous annular band (2) and friction blocks (3, 40) jointly moulded on said band (2), characterised in that it comprises the following steps: - realising said continuous annular band (2) having a body (5) of elastomer material reinforced on the inside with a substantially longitudinal reinforcement (8) , an external back (11) presenting a series of uniformly distributed teeth (12) , and an internal back (9) with a series of uniformly distributed hollows (10) ;
- with a mould (34) carrying out the joint moulding on said continuous band (2) of friction blocks (3, 40) presenting respective pairs of lateral sides (4) suited to cooperate by friction with a pulley of a speed variator, said mould (34) presenting a substantially circular seat (35) housing said continuous band (2) , a plurality of internal (37) and external compartments (36) delimited by respective internal (39) and external (38) radial septums with respect to said circular seat (35) to define respective said friction blocks (3, 40) , said external radial septums (38) delimiting respective contact surfaces (31) held by respective said friction blocks (3, 40) and one opposite the other, said contact surface (31) of a first friction block (3, 40) coming in contact against a second friction block (3, 40) adjacent to the first when said first and second friction blocks (3, 40) follow a path along a substantially rectilinear working direction.
PCT/EP2005/051278 2004-03-19 2005-03-18 Belt for a continuously variable transmission WO2005090823A1 (en)

Applications Claiming Priority (2)

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IT000185A ITTO20040185A1 (en) 2004-03-19 2004-03-19 BELT FOR A VARIABLE TRANSMISSION WITH CONTINUITY
ITTO2004A000185 2004-03-19

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Cited By (3)

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Publication number Priority date Publication date Assignee Title
DE102007024940A1 (en) 2007-05-29 2008-12-04 Contitech Antriebssysteme Gmbh Hybrid V-belt for use in continuous variable transmission, has supporting elements including increased cross-linking degree against initial state after shaping of radiation such as gamma rays, through radiation-crosslinking
WO2008145422A1 (en) 2007-05-29 2008-12-04 Contitech Antriebssysteme Gmbh Hybrid v-belt
DE102007024941A1 (en) 2007-05-29 2008-12-04 Contitech Antriebssysteme Gmbh Hybrid fan belt has multiple support elements arranged on tie beam, where tie beam width has elongation strain by formation of traction rope

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JP2001090787A (en) * 1999-09-22 2001-04-03 Bando Chem Ind Ltd Heavy load transmission v belt
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US6283882B1 (en) * 1998-10-13 2001-09-04 Bando Chemical Industries, Ltd. Heavy-duty power transmission V-belt
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US6500086B2 (en) * 2000-05-09 2002-12-31 Alexander Serkh Block type CVT belt
WO2003031841A1 (en) 2001-10-09 2003-04-17 Dayco Europe S.R.L. A belt for a continuously variable transmission
EP1327796A1 (en) * 2002-01-10 2003-07-16 ContiTech Antriebssysteme GmbH Composite V-belt
JP2003202054A (en) * 2001-10-22 2003-07-18 Mitsuboshi Belting Ltd Method for manufacturing high load transmission belt, manufacturing device and high load transmission belt

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US6500086B2 (en) * 2000-05-09 2002-12-31 Alexander Serkh Block type CVT belt
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WO2003031841A1 (en) 2001-10-09 2003-04-17 Dayco Europe S.R.L. A belt for a continuously variable transmission
JP2003202054A (en) * 2001-10-22 2003-07-18 Mitsuboshi Belting Ltd Method for manufacturing high load transmission belt, manufacturing device and high load transmission belt
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Publication number Priority date Publication date Assignee Title
DE102007024940A1 (en) 2007-05-29 2008-12-04 Contitech Antriebssysteme Gmbh Hybrid V-belt for use in continuous variable transmission, has supporting elements including increased cross-linking degree against initial state after shaping of radiation such as gamma rays, through radiation-crosslinking
WO2008145422A1 (en) 2007-05-29 2008-12-04 Contitech Antriebssysteme Gmbh Hybrid v-belt
DE102007024941A1 (en) 2007-05-29 2008-12-04 Contitech Antriebssysteme Gmbh Hybrid fan belt has multiple support elements arranged on tie beam, where tie beam width has elongation strain by formation of traction rope
DE102007024942A1 (en) 2007-05-29 2008-12-04 Contitech Antriebssysteme Gmbh hybrid V-belt

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