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
  • F16G5/20—V-belts, i.e. belts of tapered cross-section with a contact surface of special shape, e.g. toothed
• • 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

Definitions

• the present invention relates to the drive belt according to the preamble of Claim 1 below.
• a drive belt is generally used for the transmission of driving power, the drive belt being passed around two or more pulleys and clamped between them.
• a generally known use of such a transmission is the continuously variable transmission for two-wheeled motor vehicles, such as, for example, scooters.
• a continuous aim in the technological development of the known drive belt is to have a belt by means of which the transmission can transmit ever increasing power levels, or by means of which power transmission is at least constant for quite a long operational period. More particularly, such an aim amounts to achieving an increase in the tensile and/or fatigue strength of the drive belt, and also an increase in the resistance to wear of particularly the side faces or running faces of said belt, which are intended for frictional contact with the pulleys. It is also important here to limit any power loss as much as possible, not only in order to improve the efficiency of the transmission, but also in order to reduce the thermal load on the drive belt in particular, such a thermal load occurring through the development of heat as a result of friction losses. All this should preferably be achieved in such a way that air cooling will suffice, as against cooling with a recirculating liquid medium.
• Figure 1 shows diagrammatically a cross section of a continuously variable transmission provided with two pulleys and a drive belt according to the prior art.
• Figure 2 shows a first example of the known drive belt in cross section.
• Figure 3 shows a side view in cross section of a second example of the known drive belt.
• Figure 4 is a diagrammatic view in cross section of a drive belt according to a first embodiment of the basic principle of the present invention.
• Figure 5 is a diagrammatic view in cross section of a drive belt according to a second embodiment of the basic principle of the present invention.
• Figure 6 is a diagrammatic view in cross section of a drive belt according to a third embodiment of the basic principle of the present invention.
• Figure 7 is a diagrammatic view in cross section of a drive belt according to a fourth embodiment of the basic principle of the present invention.
• Figure 8 is a diagrammatic view in cross section of a drive belt according to a fifth embodiment of the basic principle of the present invention.
• Figure 9 shows a possible version of the drive belt according to the third, fourth or the fifth embodiment of the basic principle of the invention.
• FIG. 1 shows diagrammatically a cross section of a continuously variable transmission according to the prior art.
• the known transmission comprises a primary pulley 1 which can be driven by a motor (not shown) with a power torque Tp, and comprises a secondary pulley 2 which can drive a load (not shown) with power torque Ts.
• the two pulleys 1 and 2 are provided with a pulley sheave 5 fixed on the respective pulley shaft 6, 7, and with a pulley sheave 4 which is axially movable relative to said respective shaft 6, 7.
• a drive belt 20 is clamped between the pulley sheaves 4, 5, so that by means of friction mechanical power can be transmitted between the two shafts 6 and 7.
• the transmission ratio Rs/Rp of the transmission is determined by the ratio between a secondary running radius Rs and a primary running radius Rp of the drive belt 20, in other words the effective radial position thereof between the pulley sheaves 4, 5 of the respective pulleys 1 and 2.
• the abovementioned running radii Rp and Rs, and therefore the transmission ratio Rs/Rp of the transmission defined according to the invention, can be varied by making the movable sheaves 4 move in an axial direction opposite each other along the respective pulley shaft 6, 7.
• the transmission is shown by way of example with a low transmission ratio Rs/Rp, in other words with a relatively large primary running radius Rp and a relatively small secondary running radius Rs.
• FIG 2 shows in cross section a first example of the known drive belt 20, which drive belt 20 is disclosed in, for example, European Patent specification EP-A-I 217 254.
• the known drive belt 20 is provided with a self-contained tension element 25, which is composed of a number of pulling cords 31 embedded in an intermediate element 33.
• the tension element 25 is supported by a circumferential element which is substantially V-shaped in cross section or a supporting element 21 of the drive belt 20, which supporting element is provided with two largely axially directed, mutually radially outwardly diverging side faces 23 intended for frictional contact with the pulley sheaves 4, 5, which likewise diverge radially outwards with an angle ⁇ between them (see Figure 1) .
• said drive belt On the outermost radial outside of the drive belt 20 said drive belt is provided with a relatively rigid covering layer 27, which covers the supporting element 21.
• the covering layer 27 prevents the supporting element 21 from bulging excessively in the radial direction under the influence of the clamping force exerted by the pulley sheaves 4, 5 upon the drive belt 20.
• transverse elements 40 absorb the abovementioned clamping force and provide the frictional contact with the pulley sheaves 4, 5.
• the forces, or force components, acting upon the supporting element 21, or the transverse elements 40, in the radial and tangential direction or circumferential direction are transmitted to the tension element 25, which is consequently subjected to a varying tensile stress.
• the tension element 25 is also subjected to a varying bending stress through the fact that said tension element 25 is alternately bent and stretched again during rotation thereof around and between the pulleys 1, 2 of the transmission .
• the present invention provides a number of new versions of the abovementioned known drive belt types, or at any rate design aspects of said drive belt types, for which in particular the possibility of providing the drive belt 20 with great rigidity in not only its tangential or circumferential direction, but also in its axial or transverse direction was a point of departure.
• the load-bearing capacity of the drive belt 20 can be improved to a considerable extent in particular by increasing the rigidity in the abovementioned directions.
• a thin, flat or ribbon-shaped tension element 25 made of a rigid, strong material, preferably a metal, and more particularly an iron alloy, such as spring steel or maraging steel.
• the tension element 25 is preferably provided with, i.e. completely enclosed by, a corrosion-resistant covering layer, such as a metal oxide skin, a DLC
• said drive belt comprises two or more of the abovementioned ribbon- shaped tension elements 25 placed mutually concentrically, an external diameter of a radially innermost tension element 25 [a] of the two adjacent tension elements 25 corresponding to an internal diameter of a radially outermost tension element 25 [b] of said two adjacent tension elements, and an axial width dimension of the abovementioned two tension elements 25 [a], 25 [b] being adapted to each other in such a way that only the radially innermost tension element 25 [a] can come into frictional contact with the pulley sheaves 4, 5 during operation.
• An advantageous aspect of this first embodiment of the drive belt 20 according to the invention is its simple structure, in which the innermost tension element 25 [a] provides the frictional contact with the pulleys and to a great extent the transmission of torque between them, and in which the outermost tension element 25 [b] advantageously increases the axial rigidity of the drive belt 20 and absorbs part of the nominal tensile stress in the drive belt 20, which last aspect advantageously benefits the rigidity of said drive belt in the tangential direction.
• the tension elements 25 [a] and 25 [b] are preferably provided with a corresponding axial width.
• the tension elements 25 [a] and 25 [b] are also preferably connected to each other, the connection permitting at least some mutual movement in the circumferential direction. This will mean that little or no power loss will occur as a result of the friction between the individual tension elements 25 [a] and 25 [b] .
• the tension elements 25 [a] and 25 [b] are also preferably connected by means of an elastically deformable adhesive. This means that a tensile and/or shear load of the adhesive can advantageously be limited in the circumferential direction .
• said drive belt also comprises the abovementioned ribbon-shaped tension element 25, which in this case is provided with a number of local protuberances 26 separated from each other in the circumferential direction.
• An advantageous aspect of this second embodiment of the drive belt 20 according to the invention is likewise its simple structure, in which the axial rigidity of the drive belt 20 is at least partially provided, or advantageously increased, by the abovementioned protuberances 26 of the tension element 25 of said belt.
• the protuberances 26 preferably extend over at least virtually the total axial width dimension of the tension element 25.
• the protuberances 26 are also preferably provided on the tension element 25 only on the radial inside and in the axial direction centrally relative to the axial centre thereof, the axial width of the protuberances 26 being less than that of the tension element 25.
• At least the largely axially directed side faces of the tension element 25 are provided with a wear-proof and/or traction-increasing covering layer, preferably completely enclosing the tension element 25.
• said drive belt 20 likewise comprises the abovementioned ribbon-shaped tension element 25, which in this case is embedded in, or is completely enclosed by, the abovementioned supporting element 21 provided with the side faces 23 intended for the frictional contact with the pulley sheaves 4, 5.
• the supporting element 21 here is provided on either side, and at the radial height of the tension element 25, with a recess 27 which is directed axially towards the tension element 25, or the centre of the supporting element 21, and preferably extends around the entire circumference of the drive belt 20, or its supporting element 21.
• An advantageous aspect of this third embodiment of the drive belt 20 according to the invention is again its simple structure, in which the axial rigidity of the drive belt 20 is at least partially provided by, or is advantageously increased by, the supporting element 21.
• possible damage to the supporting element 21, in particular by the effect upon it of the relatively sharp edges of the thin tension element 25 under the influence of the clamping force exerted by the pulley sheaves 4, 5 ("cutting in") can be largely avoided in a particularly effective manner.
• said drive belt 20 likewise comprises the abovementioned ribbon-shaped tension element 25, which in this case is fitted on the radial outside of the abovementioned supporting element 21 provided with the side faces 23 intended for the frictional contact with the pulley sheaves 4, 5.
• An advantageous aspect of this fourth embodiment of the drive belt 20 according to the invention is again its simple structure, in which the axial rigidity of the drive belt 20 is at least partially provided by, or is advantageously increased by, the supporting element 21.
• the tension element 21 is subjected to an advantageously low degree of tensile bending stress, while the bending stresses in the tension element 25 consistent with a given running radius Rp, Rs of the drive belt 20 are advantageously minimized.
• the supporting element 21 is preferably provided on its radial inside with notches 28 extending over its axial width, which notches preferably extend in the radial direction to over half the total radial height dimension of the supporting element 21. This will limit the pushing bending stress in the supporting element 21.
• Such notches 28 are also shown diagrammatically in Figure 7 and can be used to the same effect and advantage in the drive belt 20 according to the third embodiment of the invention.
• said drive belt 20 likewise comprises the abovementioned ribbon-shaped tension element 25, which in this case is fitted centrally in the radial direction in the abovementioned supporting element 21, which element 21 is provided with the abovementioned notches 28 both on its radial inside and on its radial outside.
• the central position of the tension element 25 means that an advantageously stable frictional contact with the pulley sheaves can be achieved, while the presence of the notches 28 will ensure that both the tensile stresses and the pushing bending stresses remain limited in the supporting element 21.
• the notches 28 preferably extend in the radial direction almost to, but not entirely to the tension element 25.
• the axially directed recesses 27 shown in Figure 6 can also be used to the same effect and advantage in the drive belt 20 according to this fifth embodiment of the invention .
• the drive belt 20, or at any rate its supporting element 21, is provided with a reinforcing element 29 for increasing the axial rigidity of said drive belt.
• the reinforcing element 29 preferably comprises a self-contained thin, flat (or ribbon-shaped) ring 29 [a] with a contour which is undulating in the circumferential direction and/or a number of preferably cylindrical transverse pins 29 [b] .
• the reinforcing element 29 is preferably made of a metal or a rigid plastic or plastic composite such as a reinforced polyamide, for example reinforced with glassfibre.
• the reinforcing element 29 preferably extends therein almost, but not completely over the full axial width dimension of the supporting element 21, so that detrimental direct contact, at least detrimental in potency, between the reinforcing element 29 and the pulley sheaves 4, 5 can be avoided.
• the reinforcing element 29 can be embedded in the supporting element 21 with some play, so that a tensile and/or shearing load exerted upon the supporting element 21 can advantageously be limited.
• the reinforcing element 29 is preferably situated radially inside the tension element 25.
• the supporting element 21 is made of an elastomeric plastic or plastic composite, and its abovementioned side faces 23 are preferably provided with a wear-proof and/or traction-increasing covering layer .
• At least one of the two substantially radially directed main sides of the tension element 25 is provided with one or more grooves, preferably substantially axially directed grooves. This will advantageously influence, i.e. reinforce, an adhesion between the tension element 25 and the supporting element 21, on the one hand through the fact that the surface available for adhesion is increased and, on the other hand through the fact that the adhesion then at least partially achieves mutual engagement or positive locking of the tension element 25 and the supporting element 21.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Devices For Conveying Motion By Means Of Endless Flexible Members (AREA)
• Transmissions By Endless Flexible Members (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=38236178

Family Applications (1)

Country Status (3)

Families Citing this family (2)

Citations (13)

Family Cites Families (1)

• 2006
  • 2006-12-28 NL NL1033145A patent/NL1033145C2/nl not_active IP Right Cessation
• 2007
  • 2007-12-24 WO PCT/EP2007/064527 patent/WO2008080911A1/en active Application Filing
  • 2007-12-24 CN CN2007800502769A patent/CN101589246B/zh not_active Expired - Fee Related

Patent Citations (13)

Also Published As

Similar Documents

Legal Events