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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D53/00—Making other particular articles
  • B21D53/14—Making other particular articles belts, e.g. machine-gun belts

Definitions

• the present invention relates to a method for manufacturing a transverse element which is destined to be part of a drive belt for a continuously variable transmission having two variable pulleys, each forming a V-groove for receiving (a part of) the drive belt.
• the drive belt is provided with an endless carrier consisting of at least one, but typically two band sets and with a number of metal transverse elements arranged on and in sliding relationship with the band sets.
• a band set comprising at least one, but usually a number of
• the transverse element When describing the directions with respect to the transverse element, it is always assumed that the transverse element is in an upright position, such as is illustrated in figure 2 in a front view thereof.
• the longitudinal or circumference direction of the drive belt is at right angles to the plane of the figure.
• the transverse or width direction is from left to right and the radial or height direction is from top to bottom in the plane of figure 2.
• Each transverse element has two main body surfaces and is provided with at least one, but typically two cut-outs that are located opposite one another.
• a cut-out extends between the main body surfaces of the transverse element, and, in the drive belt, receives a band set in such a manner that a first portion of the transverse element extends below the band set, a second portion of the transverse element is situated at the same height as the band set and a third portion of the transverse element extends above the band set.
• a major part of the lower, bottom surface of the cut-out, which surface is associated with the said first portion of the transverse element, serves to support the inside of the band set in the height direction and is denoted the carrying surface hereinafter.
• This concave connecting surface is recessed, at least in part, relative to (a virtual extension of) the carrying surface and is connected to the carrying surface through a convexly curved transition surface.
• Such connecting surface favorably limits the (notch) stress level between the said first and second portions of the transverse element and, moreover, helps to urge or at least bias the band set towards the (middle of the) carrying surface, i.e. away from the said second portion of the transverse element.
• the transverse element is provided with pulley sheave contact surfaces, at two sides, which are divergent with respect to each other in a direction towards the carrying surface.
• the transverse elements are arranged along the entire
• a drive belt of this type is known from EP-A-0014013.
• the transverse elements are formed, in part, by being cut out of a piece of basic material by pressing a cutting die through such material.
• a circumferential surface of the transverse element is shaped, which circumferential surface extends between the main body surfaces thereof and includes the carrying surface (s) and the pulley sheave contact surfaces.
• the transverse element may be cut out of the basic material in a single cutting action with a single cutting die that is shaped in accordance with the transverse element to be formed thereby.
• it is also known to cut out the transverse element in several steps i.e. to form the circumferential surface of the transverse element by a number of partial cuts with a corresponding number of cutting dies that each from a part of the said circumferential surface.
• 2007/073159-A1 that a/o teaches a final cutting step that is dedicated to forming both the cut-out (s), including the carrying surface (s), and the pulley sheave contact surfaces of the transverse element.
• the invention aims to optimize the shape of the transverse element resulting from such cutting processes in relation to its use in the drive belt. According to the invention such aim is realized with the method of manufacturing the transverse element according to claim 1 hereinafter.
• EP-A-1544502 that a/o teaches that a stress in the innermost flexible metal band of the band set may be favorably minimized by maximizing the width of the carrying surface, i . e . by maximizing the widthwise support of the band set. In this latter respect EP-A-1544502 teaches that it is allowed to increase the width of the carrying surface by decreasing the width of the
• transition surface by decreasing the radius of (convex) curvature thereof, essentially without any detrimental effect to the longevity of the band set.
• the minimum radius of convex curvature of the transition surface is limited by the minimum concave curvature that can be applied to the corresponding part of the cutting die, which is about 3 to 5 mm depending on the die material and die forming process applied.
• the invention proposes to form at least the carrying surface and the connecting surface of the cut-out of the transverse element in at least two, subsequent stages.
• novel forming process also requires that at least two cutting dies are applied.
• the carrying surface is formed and in a further cutting stage and using a further cutting die the connecting surface is formed.
• the convexly curved transition surface between the carrying surface and the connecting surface is not formed by a correspondingly shaped concave part of the cutting die.
• the transition surface is in theory not formed at all, but results as a discontinuous intersection or corner between the two cuts made in the two cutting stages by the two cutting dies.
• the basic material will deform to a certain extent, due to forces exerted in the cutting stages by the cutting dies, such that typically a continuous, convexly curved transition edge is formed between the carrying surface and the connecting surface anyway.
• the radius of curvature of this latter, i.e. indirectly created, transition surface can be one order of magnitude less than that of the known transition surface. At least such transition edge can be provided with a radius of curvature smaller than 3 mm as achievable with the conventional manufacturing method.
• figure 1 diagrammatically shows a side view of a continuously variable transmission with a drive belt
• figure 4 diagrammatically illustrates a known manufacturing method for creating the transverse element
• figure 5 illustrates a step of/in the known manufacturing method of figure 4 in more detail
• figure 6 illustrates a first stage of an alternative processing step in accordance with the invention
• figure 7 illustrates a second stage of the alternative processing step in accordance with the invention.
• figure 8 diagrammatically illustrates a detail of the transverse element resulting from (the alternative processing step in
• Figure 1 diagrammatically shows a continuously variable
• the continuously variable transmission 1 comprises two pulleys 4, 5 that are arranged on separate pulley shafts 2, 3.
• a closed loop drive belt 6 is arranged around the pulleys 4, 5, and serves to transmit torque between the pulley shafts 2, 3.
• each of the pulleys 4, 5 comprises two pulley sheaves, wherein the drive belt 6 is positioned and clamped between said two pulley sheaves, so that with the help of friction a driving force may be transmitted between the pulleys 4, 5 by means of the drive belt 6. (In figure 1, only one of the pulley sheaves of each of the pulleys 4, 5 can be seen) .
• the drive belt 6 comprises an endless carrier 7 consisting of at least one, but typically two band sets 7 that (each) comprise at least one, but typically a number of concentrically nested, flexible endless metal bands.
• endless carrier 7 consisting of at least one, but typically two band sets 7 that (each) comprise at least one, but typically a number of concentrically nested, flexible endless metal bands.
• transverse elements 10 are arranged, which transverse elements 10 are moveable with respect to the endless carrier 7 in the circumference direction thereof.
• transverse elements 10 are shown in figure 1.
• both the endless carrier 7 and the transverse elements 10 are made of metal, in particular steel.
• FIGS. 2 and 3 show a transverse element 10.
• a first main body surface of the transverse element 10 is indicated in general by the reference sign 11, whereas a second main body surface of the transverse element 10.
• transverse element 10 is indicated in general by the reference sign 12.
• a circumferential surface 17 is extending between the main body surfaces 11, 12.
• the transverse element 10 comprises successively a first or basic portion 13 that is generally trapezoidal shaped, a relatively narrow second or neck portion 14 that is generally rectangular shaped, and a third or top portion 15 that is generally triangular shaped.
• the basic portion 13 is located at the side of the inner circumference of the drive belt 6, whereas the top portion 15 is located at the side of the outer circumference of the drive belt 6.
• At least a portion of the first main body surface 11 of the transverse element 10 abuts against at least a portion of the second main body surface 12 of a subsequent transverse element 10
• at least a portion of the second main body surface 12 of the transverse element 10 abuts against at least a portion of the first main body surface 11 of a preceding transverse element 10.
• the transverse element 10 further comprises two cut-outs 16 that are located opposite one another.
• a cut-out 16 extends between the main body surfaces 11, 12 of the transverse element 10, and, in the drive belt 6, receives a band set of the endless carrier 6 in such a manner that the basic portion 13 extends below the band set, the neck portion 14 is situated at the same (radial) level as the band set and a top portion 15 extends above the band set.
• the basic portion 13 comprises two pulley sheave contact surfaces 18.
• the transverse element 10 moves over the pulley 4, 5, contact between the transverse element 10 and the pulley sheaves is realized through said pulley sheave contact surfaces 18.
• a depression 19 is arranged in the top portion 16, which depression 19 is depicted by means of dashed lines in figure 3.
• the depression 19 corresponds to a projection 20 on the second main body surface 12.
• the projection 20 of the transverse element 10 is at least partially located in the depression 19 of a subsequent
• transverse element 10 The projection 20 and the corresponding depression 19 serve to prevent, or at least limit, mutual displacement of adjacent transverse elements 10 in a plane perpendicular to the circumferential direction of the drive belt 6.
• a tilting edge 21 and a step 22 are arranged at the first main body surface 11 of the transverse element 10. Both the tilting edge 21 and the step 22 are arranged in the basic portion 13 and extend substantially axially, i.e. widthwise thereon. Radially inward from the tilting edge 21 the said basic portion is effectively tapered.
• the tilting edge 21 allows a mutually tilting or rotation of two mutually contacting transverse elements in the drive belt, such as occurs in the arc shaped path of the
• the said cut-outs 16 are bounded by parts of the circumferential surface 17 of the transverse element 10, which parts comprise:
• the said connecting surface 26 provides a smoothly concavely curved, gradual transition between the carrying surface 23 and the side faces 24 of the neck portion 14 and, at least largely, does not arrive in contact with the endless carrier 7.
• transverse elements 10 are created in a number of
• step 22 of the final transverse element 10 is included in the shape of the strip 30.
• transverse elements 10 are created in pairs, wherein the top portions 15 of a respective pair of transverse elements 10 are directed towards each other, and wherein the basic portions 13 of such transverse elements 10 are located at the side of the strip 30.
• the processing steps A-H are taking place on both sides of a central axis 31 of the strip 30 in a mirror-symmetrical fashion relative to such axis 31.
• the intermediately shaped transverse elements 10 are referred to as basic elements 32.
• four portions are cut from the strip 30 by means of four cutting dies 41.
• the cut-outs 16 of four basic elements 32 are roughly shaped, i.e. are pre-formed as recesses 33.
• a third step C six further portions are cut from the strip 30 by means of six further cutting dies 44.
• large parts of the circumferential surface 17 of the final transverse element 10 are formed.
• the result that is obtained after carrying out this third processing step C is depicted in a section marked "I" of figure 4.
• a small connecting element 36 remains between the basic element 32 and a remaining central part or "backbone" 35 of the strip 30.
• a shaping die 45 is pressed into the basic element 32.
• at least the tilting edge 21 is formed on the first main body surface 11 of the basic elements 32.
• a pin shaped shaping die 46 is pressed into the basic element 32.
• the depression 19 is formed on the first main body surface 11 of the basic element 32 and the corresponding projection 20 is formed on the second main body surface 12 of the basic element 32 as well.
• a sixth steps F the cut-outs 16 of the basic elements 32 are accurately and finally cut at the location of the afore-mentioned recesses 33 by means of four further cutting dies 47.
• transverse element including the said carrying surface 23, the said side face 24, the said top surface 25 and the said connecting surface 26.
• a seventh and last step G of the known method the basic element 32 is cut loose from the backbone 35 of the strip 30 to finally create the transverse element 10, by cutting through the connecting element 36 by means of yet a further cutting die 48. It is noted that in the example of figure 4 the said step 22 of the final transverse element 10 is already included in the shape of the strip 30.
• the present invention was conceived as an improvement of the cutting of at least the carrying surface 23 and the connecting surface 26 of the bottom portion 13 of the transverse element 10, such as occurs as part of the sixth processing step F of the above-described, known manufacturing method.
• this sixth step F of the known manufacturing method is shown in more detail in figure 5 in a close-up view of a section of the basic element 32 centered on the recess 33 thereof formed in the said first processing step A.
• the darker solid line indicates the contour of the basic element 32 prior to the sixth cutting step F
• the hatched area 47 represents the basic shape of the further cutting die 47 that cuts and forms the final contour of the cut-out 16 in the said sixth processing step F.
• This figure 5 shows that in the known manufacturing method both the carrying surface 23 and the connecting surface 26 are simultaneously formed, i.e. with the same cutting die 47 and in the same cutting action. Indeed, in the known method the entire circumference of the cut-out 16 is simultaneously formed. With the known manufacturing method a convexly curved transition surface 27 is formed between the carrying surface 23 and the connecting surface 26, which is clearly visible in the figure 5 (see also figure 2) .
• a radius of (convex) curvature of such transition surface 27 can be small, but in practice will always have a certain value larger than zero, because of a minimum concave curvature that can be applied to the corresponding part of the said further cutting die 47 that is used for cutting the cut-out 16. Moreover, a natural smoothening of such transition surface 27 will occur, even if it is formed by the sharpest of possible corners in the said further cutting die 47.
• the invention proposes a novel manufacturing method, which method is illustrated in figures 6 and 7 hereof.
• the manufacturing method according to the invention includes, irrespective of any other preceding or succeeding processing steps, the processing step of forming the carrying surface 23 (see figure 6) and of the connecting surface 26 (see figure 7) in two separate stages using two separate cutting dies 49, 50, namely a carrying surface cutting die 49 and a connecting surface cutting die 50.
• these two surfaces 23, 24 can be formed to connect to one another at a comparatively sharp (transition) edge 28, thus minimizing the (widthwise) extent of the transition there between.
• the widthwise extent of the carrying surface 23 is allowed to be favorably maximized in the direction of the said side face 24.
• the carrying surface 23 is formed in advance of the forming of the connecting surface 26, because the recess 33 then gives easy access for the connecting surface cutting die 49.
• the carrying surface cutting die 49 also forms a rough shape of the connecting surface 26, as well as a part of the final shape of the said side face 24.
• the connecting surface 26 is formed in advance of the forming of the carrying surface 23 (not illustrated) .
• the connecting surface cutting die 50 cuts through and is supported by the base material 30 along the entire circumference thereof, which typically improves the accuracy of the cut and thus favorable also the accuracy of the shape and/or the dimensions of the end-product transverse element 32.
• the connecting surface cutting die 50 may be shaped to cut not only the connecting surface 26, but also the said side face 24 in full (not shown) .
• the alignment between the connecting surface cutting die 50 and the connecting surface cutting die 49 is favorably less critical than in arrangement illustrated in figure 6 hereof, because in this case the dies 49 and 50 do not adjoin in the plane of the said side face 24, but rather in a line, i.e. in the edge between the said side face 24 and the said top surface 25.
• Figure 7 provides a close-up of the transition between the carrying surface 23 and the connecting surface 26 as made possible by the present invention, i.e. in the from of the transition edge 28.
• transition surface 27 as formed in the

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• Punching Or Piercing (AREA)

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Citations (6)

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• 2011
  • 2011-12-30 NL NL1039275A patent/NL1039275C2/en active
• 2012
  • 2012-12-28 WO PCT/EP2012/077071 patent/WO2013098401A1/en active Application Filing
  • 2012-12-28 CN CN201280065598.1A patent/CN104094017B/zh active Active
  • 2012-12-28 JP JP2014549494A patent/JP6203193B2/ja not_active Expired - Fee Related

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