NL1043519B1 - A transverse segment for a drive belt, a drive belt including such transverse segment and a continuously variable transmission with the drive belt including such transverse segment - Google Patents

Abstract

The present invention concerns a transverse segment (1) for a drive belt (50) comprising a row of such transverse segments (10) mounted on a ring stack (8). The transverse 5 segment (10) defines a central opening (5) between a base part (10) of the transverse segment (10) and two pillar parts (11) thereof extending from a respective side of the base part (10) for accommodating the ring stack (8). Each pillar part (11) is provided with a cone-shaped protrusion (6) that protrudes from a front surface (2) of the transverse segment (1) and with a correspondingly cone-shaped cavity (7) that is provided in a back 10 surface (3) thereof. According to the invention a cone half-angle of both the protrusion (6) and the cavity (41) has a value in the range from 3.5 to 6.5 degrees with 5 degrees as the optimum value. 1043519

Description

A TRANSVERSE SEGMENT FOR A DRIVE BELT, A DRIVE BELT INCLUDING SUCH TRANSVERSE SEGMENT AND A CONTINUDUSLY VARIABLE TRANSMISSION

WITH THE DRIVE BELT INCLUDING SUCH TRANSVERSE SEGMENT This invention relates to a transverse segment that is destined to be pant of a drive belt for a continuously variable transmission with two pulleys and the drive belt. Such a transmission is commonly known and is, for example, applied In the drive train of passenger cars and other motor vehicles. In the transmission the drive belt runs around and between the pulleys that are each provided with two conical sheaves that define a V- groove wherein a respective circumference part of the drive belt is held. The width of the V-groove of the pulleys can be changed in mutually opposite directions, by moving the pulley sheaves towards, respectively away from one ancther, to control a radius at which the drive belt is {effectively In friction contact with the respective pulleys, le. to control a speed ratio provided by the transmission within a continuous range between a smallest anda largest speed ratio.

A known type of drive belt comprises an essentially contiguous row of transverse segments made of steel that are mounted on and around the chrcumference of a rng stack composed of a number of flexible endless bands or rings that are mutually stacked, one around the other, and that are Bkewise made of steel.

In the above and below description, the axial, the radial and the creumfersnce directions are defined relative to the drive belt when placed in a circular posture. A thickness direction and a thickness dimension of the transverse segments are defined in the said circumference direction, a height direction and a height dimension of the fransverse segments are defined in the said radial direction and a width direction and a width dimension of the transverse segments are defined in the said axial direction. A thickness direction and a thickness dimension of the rings and of the ring stack are defined in the said radial direction, a width direction and a width dimension of the rings and of the ring stack are defined in the said axial direction and a length direction and a length dimension of the ring stack is defined in the sald circumference direction. Up and down directions and above and below positions are respectively defined in radial outward and radial inward direction, The known flexible ring Is provided with an essentially rectangular cross-section, such that it has a radial dimension or thickness that Is much smaller than its axial dimension or width, typically by a factor of at least forty to one hundred or more, Also in absolute terms, the thickness of the ring is small amd typically has a value of 185 Zo 200 micrometer, such that it can bend relatively easily in its circumference direction. In the ring stack, a number of such rings are arranged mutually concentric, le, are nested with narrow tolerance, such that these share the load when the drive helt is operated in the transmission.

The known transverse segments each define a central opening that is open 5 towards the radial outside of the drive belt and that accommodates and confines a respective circumference section of such ring stack, while allowing the transverse segment to move along the circumference thereof, This central opening is defined by and between a base part of the transverse segment that is located radially inward of the ring stack and two pillar parts thereof that respectively extend from a respective side of the base part in radial outward direction.

The two pillar pans thus define respective axial boundaries of the central opening, whereas in radial inward direction the central opening it is bounded by the hase part.

In radially outward direction the central opening is at least partly closed hy some means, in order to confine the ring stack to the central opening.

This type of drive belt is, for example, known from the British patent GB1288777-A and, more recently, from the international patent publication WO2018/21D456-A1. It is noted that according io these documents, the said means for confining the ring stack in radial outward direction are embodied by respective hook portions of the pillar parts that each extend axially towards the respectively other, Le. axially opposite, pillar part at some distance away from the base part, These hook portions of the transverse segment can have equal axial extent or such axial extent can be different between the two hook portions, in which cass these respective hook portions are preferably provided on opposite sides of the transverse segment for successive transverse segments in the drive belt, as afo taught by WOZD18/210458-A1. As seen in radial direction, an cuter porfion of the known transverse segment is provided with an essentially constant thickness, whereas a thickness of an inner portion thereof decreases in radially inward direction.

In between the said mer and outer portions, a front surface of the transverse segment, facing In a drcumference direction of the drive belt, includes a width-wise extending surface part that is curved In radial direction and that is offen referred to In the art as a rocking edge or a tliting zone, The rocking edge allows successive transverse segments in the drive bell to mutually rotate about the axial direction, while these remain in contact at the rocking edge, whereby the dive belt as a whole follows a curved trajectory, Although the rocking edge can be located in the base part of the transverse segment, it is preferably located at least partly in the pillar parts thereof, During operation in the transmission, the ring stack is tensioned by the transverse segments being urged in radial outward direction at the two pulleys by being damped between the conica! discs thereof.

At these pulleys, the drive helt thus follows a curved trajectory, in which curved trajectory pars the tansverse segments bear against the radial inside of the ring stack through, at least, a part of the surface of their base part that is located between the pillar parts, which surface pan is denoted a bearing surface hereinafter.

Dus ta the sald tensioning thereof at the pulleys, the ring stack extends essentially straight between the two pulleys, while guiding the transverse segments as these traverse from the one pulley to the other in such straight trajectory parts, lt is common practice ìn the art to provide the transverse segment with a protrusion projecting from the said front surface or from an oppositely facing rear surace id thereof and with a corresponding, however somewhat larger cavity in ifs respectively opposite main surface, In the row of transverse segments in the drive belt, the protrusion of a first transverse segment is received in the cavity of a second, Le. adjacent transverse segment, at least in part.

Hereby, a mutual displacement of the successive fransverse segments perpendicular to the circumference direction of the drive helt is limited to a play of the protrusion inside the cavity.

The protrusions and cavities thus serve to both mutually align the transverse segments in a row in the straight parts of the drive belt's trajectory and ta limit a rotation thereof in the said curved trajectory parts.

In particular, at least a pitching (i.e. rotation about the axial direction) and a yawing {i.e rotation about the radial direction} of the transverse segments and preferably also a rolling (Le. rotation about the tangential direction) of the transverse segments relative to the ring stack is limited thereby.

The known transverse segments sach include a single protrusion (and corresponding cavity) provided centrally in its base pan and/or two protrusions (and corresponding cavities), one provided in each of it pillar parts.

Typically jn the art, a play of between 0.015 to 0.05 mm and preferably of around 0.0258 mm is applied in any direction perpendicular to the drcumierence of the protrusion, Le. between the inner circumference of the cavity and the outer drcumference of the protrusion that is centrally located therein, it is noted that, conventionally, the protrusions and the cavities have a frustp- conical shape, Le. are shaped as a truncated cone, as required by the preferred mould press-forming process thereof.

In practice the protrusions and the cavities are provided with a cone half-angle (Le. half the top angle of the said frusto-conical shape thereof) of at least 7 to B degrees, with a theorstical preference toward larger values expressed by EP1662173-A1 and by WOZ012/051548-A1. Underlying the present invention is the general development aim to improve upon the existing drive belt design and existing design considerations In terms of the wear resistance and/or the fatigue strength of the known drive belt.

An improvement in this respect is surprisingly, Le. in contrast with the prevailing technical knowledge, observed when the conicity of the protrusion and the cavity of the transverse segments of the drive belt is decreased relative to the said existing design, while maintaining the play there between within the known, i.e. conventionally applied range.

in the presently considered design of the drive belt, the ring stack is confined in apposite axial directions, Le. width-wise, in the central openings of the transverse segments, by and between the pillar parts thereof. The width of the ring stack is somewhat smaller than the width of the central openings of the transverse segments fo accommodate a mutual misalignment of, ie, axial offset between the pulley V-grooves that occurs during operation of the transmission in dependency on the speed ratio, as alo taught by US4820242. Nevertheless, such axial clearance of the ring stack relative to the transverse segments cannot prevent contact between the ring stack and the pillar parts altogether during operation of the drive helt, by which contact the ring stack is worn. Therefore, it is beneficial to the overall performance of the drive belt, to reduce the 1&8 severity of such contact, e.g. in terms of a rate of incidence and/or an intensity thereof. By applying the cone half-angle according fo the present invention, it is realised that a relative movement in axial direction between the successive transverse segments is minimal also when the protrusions thereof are not fully inserted in respective cavities, such that a preferred alignment of the transverse segments relative Ia the ring stack is promoted and the said contact severity is favourably reduced, After all, by minimizing such axial play between the protrusions and the cavities, the axial clearance between the transverse segments and the ring stack is maximised.

In particular according to the present invention, the cone half-angle has a value in the range from 3.5 to 6,5 degrees, with 5 degrees as an optimum value, In relation to the lower boundary of such range it is noted that het only unwanted side effects start to take over, hut also that it becomes increasingly more difficult to release the protrusion from a mould after press-forming # in such mould, Further according to the present invention, the said axial clearance of the ring stack relative to the transverse segments can in this case be set favourably small, in particular at 8% or less of the width of the dng stack in relative terms, or, inn absolute terms, only 1.5 to 2 times a maximum axial offset of the pulley V-grooves in the transmission that typically amounts to 0.4 to 0.5 mm, The above-described invention and the technical working principles underlying the invention will now be explained further with reference to the drawing figures, whereof: ~ figure 1 is a simplified and schematic side elevation of a known transmission with two pulleys and a drive belt consisting of a ring stack and a row of Yansverse segments mounted on the ring stack along the craumference thereof;

- figure 2 schematically illustrates the known drive beft in a cross-section thereof facing in its circumference direction and also includes a separate, transverse cross-section of only the transverse segment thereof; - figure 3 schematically MHlustrales a section of the known transverse segment in an 5 enlargement; - figures 4A and 4B schematically illustrate an operational aspect of the known drive belt and ~ figure 5 is a graph illustrating technical considerations underlying the present invention, Figure 1 schematically shows, in a cross-section thereof, the central parts of a continuously variable transmission 51 for use jn a driveline of, for example, passenger motor vehicles. This transmission 51 is well-known and comprises atleast a first variable pulley 52, a second variable pulley 53 and a drive belt 50 fitted around these pulleys 52,

53. In the driveline, the first pulley 52 is coupled to and driven hy a prime mover of the vehicle, such as an electric motor or a combustion engine, and the second pulley 53 is coupled to and drives a driven whes! of the vehicle, typically via a number of gears. The pulleys 52, 53 each typically comprise a first conical sheave that is fixed to a respective pulley shaft 54, 55 and a second conical sheave that is axially displaceable relative to such respective pulley shaft 54, 55 and that is fixed thereto in rotational direction. As appears from figure 1, the trajectory of the drive belt 50 in the transmission 51 includes two straight parts ST, where the drive belt 50 crosses over hetween the pulleys 52, 53 and two curved parts CT where the drive belt SD ís wrapped around the two pulleys 52, 53 while being accommodated between the conical sheaves thereof, The drive belt 50 is composed of a ring stack S and a plurality of transverse segments 1 that are mounted on the ring stack B along the circumference theres! In an, al least essentially, contiguous row. For the sake of simplicity, only a few of the transverse segments 1 of the dive belt 50 are shown in figure 1, which transverse segments 1 are, moreover, not drawn to scale in relation to, for example, the diameter of the pulleys 52, 53. In the drive belt 50, the transverse segments 1 are movable along the circumference of the ring stack 8, which ring stack 8 is composed of a number of relatively thin and flexible endless steel bands or rings that are mutually nested, as can be seen more clearly in figure 2 that shows the ring stack 8 with eight individual tings. During operation of the transmission 51, the transverse segments 1 of the drive belt 50 car be driven by the first pulley 52 In the direction of rotation thereof hy friction. These driven transverse segments 1 push preceding transverse segments 1 in the circumference direction of the ring stack 8 and, ulimately, rotationally drive the second pulley 53, again by friction. In order to generate such Fiction {force} between the transverse segments 1 and the pulleys 52, 53, the said pulley sheaves of each pulley 52, 53 are urged towards each other, whereby these clamp the transverse segments 1 between them in the respective curved trajectory part CT of the drive belt 50, To this end, slectronically controllable and hydraufically acting movement means {not shown) 5 that act on the moveable pulley sheave of each pulley 52, 53 are provided in the transmission 51. These movement means also control respective radial positions Ri and R2 of the drive belt 50 at the pulleys 52, 53 and, hence, the speed ratio that Is provided hy the transmission 51 in the driveline between the pulley shafts 54, 55 thereof.

Also during operation of the transmission 51 drive belt 50, the transverse members ae urged radial outward by being clamped between the conical pulley sheaves and are being forced into contact with the radial inside of the ring stack 8 that is tensioned thereby. Since, as mentioned hereinabove, in the drive belt 50 the transverse segmeris 1 can move relative to the ring stack § along the circumference thereof, the ring stack B is tensioned to a relatively low level in relation ia a torque transmitted by the drive belt 50 between the pulleys 52, 53, at least compared ic other types of drive belt In figure 2 the known drive belt 50 is schematically illustrated in more detail, On the left side of figure 2 the drive belt 30 is shown In a cross-section thereof facing in circumference direction and on the right side of figure 2 a cross-section A-A of only the fransverse segment 1 is included. From figure 2 it appears that the transverse segments 1 of the drive belt 50 are generally shaped similar to the letter "V", Le. are generally V- shaped. In other words, side faces 12 of the transverse segments 1 through which i arrives in {friction} contact with the pulleys 52, 53, are mutually diverging in radial outward direction by being oriented at an angle that closely matches an angle that is present between the conical sheaves of these pulleys 52, 53. The pulley contact faces 12 of the transverse segment 1 are typically either corrugated by a macroscopic profile or are provided with a rough surface structure, such that only the higher lying peaks of the corrugation or of the surface roughness arrive in contact with the pulleys 52, 53. This particular feature of the transverse segment design provides that the friction between the drive belt 50 and the pulleys 52, 53 is optimised by allowing cooling oll that is applied in the known transmission 51 to be accommodated in the lower Wing paris of the corrugation or of the surface roughness.

Each fransverse segment 1 includes a base part 10 and two pillar parts 11, whereof the base part 10 extends mainly in the axial direction of the drive belt 50 and whereof the pillar parts 11 extend mainly in the radial direction of the drive belt 50, each from a respective axial side of the base part 10. In its thickness direction, the transverse segment 1 extends between a front main body surface, Le. front surface 2 and a rear main body surface, Le. rear surface 3 thereof that are both oriented, at least generally, in the circumference direction of the drive belt 50. An opening 5 is defined centrally between the pillar parts 11 and the base part 10 of each transverse segment 1, wherein a circumference section of the ting stack B is accommodated. In radial outward direction § the central opening 5 is partly closed-off by respective hook portions 3 of the pillar paris

11. Each such hook portion 9 extends from a respective pillar part 11 generally in the direction of the respectively opposite pillar part 11, Thus, the hook portions 9 confine the ring stack 8 to the central opening 5 of the transverse segment 1 in radial outward direction. In between the pillar parts 11, the base part 10 defines a bearing surface 13 for confining and supporting the ring stack 8 in radially inward direction, As illustrated in figure 2, the bearing surface 13 is a central part of a boundary surface of the central opening 5 that is defined by the base pan 10 In radially inward direction and that thus wedominantly extends in the axial and circumference directions of the drive belt 50. The bearing surface is convexly curved in, at least, the axial directors in a wellknown manner, for realising, or at least promoting, a desired contact and irteraction between the fransverse segment 1 and the ring stack 8. On either side of bearing swface 13 the said boundary surface of the base pat 10 futher includes a transition surface 15 forming a transition between the bearing surface 13 and a side surface of a respective pillar pan 11 facing the central opening 5, Typically, such ransition surfaces 15 include a convey cwved part adjoining the bearing surface 13 and a concavely curved part adjoining the said side surface of the respective pillar pan 11, it is noted that convexly curved part of the transition surfaces 15 is curved according to a much smaller {e.g. by factor of 0.1 or less) radius of curvature than the beating surface 13 is curved.

Beth pillar parts 11 of the transverse segment 1 are provided with a protrusion 6 that protrudes in thickness direction from the front surface 2 of the transverse segment 1 and with a corresponding, however somewhat larger cavity 7 In the opposite side of the respective pillar part 11, Le. in the rear surface 3 of the transverse segment 1. In the row of ransverse segments 1 in the drive belt 80, the protrusions § of a first transverse segment 1 are received in the cavitles 7 of a second, Le, adjacent transverse segment 1. By this engagement of the protrusions 6 and the cavities 7 of successive transverse segments 1, the transverse segments 1 mulually ink to and align ong another in radial direction and In axial direction in the said row thereof in the drive belt 50. In figure 2, the diameter of the cavity 7 is exaggerated relative to the diameter of the protrusion 6 to jHustrate a play that exists there between,

Also In the said row of transverse segments 1 in the drive belt 50, at least a part of the front surface 2 of a first transverse segment 1 abuts against at least a part of the rear surface 3 of a second, Le. adjacent transverse segment 1. Abulling fransverse segments 1 are able to tilt relative to one another, while remaining in mutual contact at and inough an axially extending, convexly curved surface part 4 of the front surface 2 thereof that is denoted rocking edge 4 hereinafter. Above, Le. radially outward of such rocking edge 4, the fransverse segment 1 has an essentially constant thickness, whereas below, Le. radially inward of such rocking edge 4, the transverse segment 1 is tapered, je, has a thickness that decreases in radially inward direction (whether gradually, stepwise or by a combination therenf}, to allow for the afore-mentioned relative tilting without interference between the respeclive base parts 10 of the abutting transverse segments 1. ff is noted that, although in figure 2 the rocking edge 4 is located partly in the pillar parts 11 and partly in the base part 10 of the transverse segment 1 such that £ overlaps with the bearing surface 13 in radial direction, it is also known to locate the rocking edge 4 fully in the base part 10, Le. radially inward of the bearing surface 13, In edther case, the rocking edge 4 is preferably provided in two parts da, 4b separated hy the central opening 5 and/or by a recessed area 14 in the front surface 2 of the transverse segment 1 that is recessed in thickness direction relative to the rocking edge

4. The recessed area 14 provides a channel between the abutting fransverse segments 1, allowing lubricant to How from radially inside the drive belt 50 to the radial inside of the ring stack B. Such lubricant is supplied to the transmission during operation, not only for cooling it, but also for lubricating the dynamic contact between the transverse segments 1 and the ring stack 8, as well as between the individual rings of the ring stack 8. it is further noted that in the embodiment of the fransverse segment 1 illustrated in figure 2, wherein the rocking edge 4 is located partly in the pillar parts 11 and the base part 10 of the transverse segment 1, the recessed area 14 is, in part, formed as a curved transition surface between the front surface 2 of the transverse segment 1 and the bearing surface 13 as an inevitable side-effect of the preferred manufacturing method of fine-blanking the transverse segment In fine-blanking, the transverse segment 1 is cut from basic material hy pressing a punch, having a contour corresponding to that of the transverse segment 1, through the basic material into a transverse segmernt-shaped hole of a die plate, while being supported by a counter punch on the opposite side thereof. An end face of the counter punch that contacts the basic material is a/o shaped to form the rocking edge 4 and is provided with a recess that serves as a mould for forming the protrusion 6, while the end face of the punch that contacts the basi material is protruding part to form the cavity 7.

As further fllustrated in figure 2, the pulley contact faces 12 of the transverse segment 1 extend in radial direction from the underside of the base part 10 fo somewhat above the rocking edge 4, Le, partly in the pillar parts 11, However, such radial extend can also be less, e.g. the pulley contact faces 12 can be confined to the base part 10, or more, &.g. of the pulley contact faces 12 can extend in the pillar parts 11 to radially outward of the ring stack 8. Figure 3 shows the protrusion 6 and the cavity 7 of one of the pillar parts 11 in more detall according to the cross-section B-B indicated in figure 2 for two successive transverse segments la, ib. In figure 3 # is visible that the protrusions 8 and cavities 7 have a {frustp-joonical shape with the same cone half-angle @. Figure 3 further shows that a play is provided between the outer circumference of the protrusion 6 and the inner circumference of the cavity 7. This play between the protrusion 8 in the cavity 7 a/0 allows the successive transverse segments 1a, ib to slide relative to zach another in the IS axial direction, as is schematically indicated in figure 44, and/or to rotate about the radial direction between the pulley sheaves 56, 57, as is schematically indicated In figure 48. )t can be seen that, by either one of these movements, an effective width We of the central openings 5 of the transverse segments 1 that is available for the ring stack 8 extending through the openings 5 decreases, ie. becomes less than an actual width Wa thereof the central opening 5, as measured perpendicular between the pillar paris 11 of an individual transverse segment 1. As a result also a clearance in axial direction of the ring stack 8 relative to the transverse segments 1 decreases and/or a width of the ring stack 8 that can maximally be applied in the drive belt 50 decreases. Both these later side effects of the said play between the protrusion 6 in the cavity 7 are undesirable, because the overall performance of the drive belt 50 In terms of Its longevity and/or its load carrying ability are adversely affected thereby, However, al the same time, the said play is known to be necessary for the proper funciioning of the didve belt 50 in the transmission. For example for allowing the drive belt 50 to accommodate a mutual misalignment of, Le, axial offset between the pulleys 52, 53 that occurs ìn practice in dependence on the speed ratio. Nevertheless, according to the present invention, an improvement can in this respect be realised.

Underlying the present invention is the observation, llustrated in Figure 3, that the said play between the protrusion 8 and the cavity 7 increases as the protrusion 8 is increasingly refracted from the cavity 7, due to their conical shape. The said play has a smallest value when the protrusion 8 is maximally inserted in the cavity 7, ie. when the successive transverse segments 1 are mutually contacting while being aligned in parallel, In a first approximation such smallest play value increases, in relation to the distance D between the successive transverse segments la, 1b at ot near the protrusion 8 and cavity 7, by the mathematical product of such distance D and the sine of the cone half angle q of the protrusion B and the cavity 7. According to the present invention it is § beneficdal to reduce the said increase of the smallest play value, by providing the protrusion 6 and the cavity 7 with a reduced cone half-angle ¢ relative to the state of an. Hereby, it is realised that a relative movement in axial direction between the successive transverse segments 1a, ib is minimal also when the protrusions & thereof are not fully inserted In respective cavities 7, 19 In particular according to the present invention, the cone half-angle ¢ of the protrusion B and the cavity 7 has a value In the range from 3.5 to 6,5 degrees that is indicated in the graph of figure 5 on the X-axis. The straight ine in the graph of figwe 5 plots the difference between the actual width Wa of the central openings 5 of the transverse segments 1 and the effective widih We thereat in relation to such cone half 15 angie op the . Smaller values of such difference Wa-We, Le, smaller values of the cone half-angle o, are preferable for minimising the occurrence and/or severity of the contact between the ring stack 8 and the pillar parts 11 of the transverse segments 1 during operation of the drive belt 50, However, as schematically indicated in the graph of figure by the curved line, such smaller values of the cone half-angle ¢ are Increasingly difficult to manufacture in the preferred manufacturing process of the transverse segments 1 of fine-blanking with a value of about 3 degrees providing a lower boundary in practice.

The present invention, in addition to the entirety of the preceding description and all details of the accompanying figures, also concerns and includes all the features of the appended set of claims, Bracketed references in the claims do not limit the scope thereof, but are merely provided as non-binding examples of the respective features. The claimed features can be applied separately in a given product or a given process, as the case may be, but kis also possible to apply any combination of two or more of such features therein, The Invention is not limited to the embodiments and/or the examples that are explicitly mentioned herein, but also encompasses amendments, modifications and practical applications thereof, in particular those that lie within reach of the person skilled in the relevant aft,

Claims (4)

CONCLUSIONS i A transverse segment {1} for a drive belt (50) with a belt package {8} consisting of a number of inter-nested belts and with a number of such transverse segments (1) successively and movably placed on the belt package {8}, which transverse segment {1) is provided with a central opening {5} for receiving the belt package {8} of the drive belt {50}, which central opening (5) is bounded on an underside thereof by a base portion {10} of the transverse segment {1} and on either side thereof through zen or pillar part (11} of the transverse segment (1) i0, which pillar parts {11} extend on either side of the opening {323} from the hasis portion {10} and which are provided with sen tapered projection {6) on a front face {2} of the transverse segment {1} and of a tapered recess (7} in a posterior face {3} thereof, with the cherry peak that half apex angle of the tapered projection {6 } and the tapered recess (7) se n has a value in the range of 3.5 to 8.5 degrees and is preferably equal to 5 degrees, The transverse segment {1} according to claim 1, characterized in that between a calf diameter of the projection (8) and an inner diameter of the recess (7) there is a play which has a value in the range of 0.015 to 0. 0.05 mm and preferably equal to 0.025 mm. A drive belt {50} with a belt package (8) consisting of a number of inter-nested belts and with a number of transverse segments {1} placed in succession and movably on the belt package {8) according to claim 1 or 2, characterized in that in a width direction of the belt package (8) there is a clearance between the belt package {8} and the two pillar parts (11) of the transverse elements {1} of at most 6% of a width of the belt package {B}. 4. A continuously variable transmission (51) with two variable pulleys (52, 53}, each defining a V-groove with a variable width, and with a drift belt {50} according to claim 3, which wraps around the pulleys (52, 53) is driven through its V-grooves, characterized in that during operation of the transmission {51} a maximum axial offset is created between the V-groove of the pulleys {§2, 83) and that in the width direction of the belt package (8) there is a play between the belt package {B} on the two pillar parts {11} of the transverse elements {1} of at least 1.5 and at most 2 times the stated maximum axial offset between the V-grooves of the positions (52, 53).