JP6685131B2 - Drive belt with various types of transverse elements for continuously variable transmissions - Google Patents

Description

  The present disclosure relates to drive belts for continuously variable transmissions. The drive belt is especially adapted to be arranged around the two pulleys of the transmission and supports and guides the individual transverse elements for contacting the pulleys as well as the transverse elements in the transmission. For carrying one or more endless or ring-shaped carriers. Drive belts of this kind are also already known as push belts.

  The endless carrier of the drive belt is composed of a plurality of continuous, flexible metal belts which are nested in one another and are also known as ring sets. The endless carrier is at least partially inserted into a recess provided in the transverse element. If the drive belt comprises only one endless carrier, such carrier is typically mounted in the central recess of the transverse element. The central recess is open outward in the radial direction of the drive belt. However, the drive belt is usually provided with at least two endless carriers, which are mounted in respective ones of the two recesses of the transverse element. The recess is open towards the transverse element, i.e. axially or laterally, respectively, of the drive belt.

  The transverse elements of the drive belt are arranged so as to be slidable along the circumference of the endless carrier or carriers in a substantially continuous row, whereby these elements are arranged so that the drive belt moves. Can transmit the force about. The transverse element has two main faces, which at least partially extend substantially parallel to each other, the main faces being defined by the circumferential flanks of the transverse element. They are separated from each other over the (local) thickness of the transverse elements. As a result, the first surface or the front surface of the main body (which is hereinafter referred to as the front surface) faces the first longitudinal direction of the drive belt, while the second surface or the rear surface of the main body (which is referred to as the front surface). In the following, referred to as the back surface) faces the second longitudinal direction of the drive belt, which is opposite to the above-mentioned first longitudinal direction.

  When viewed along the circumference of the carrier, the transverse elements have rather small dimensions or thicknesses, with hundreds of transverse elements present on the drive belt. Adjacent transverse elements must be able to tilt with respect to each other so that the belt follows the curved track. To accommodate and control such relative tilting, the front of the transverse element is provided with a so-called locking edge of axially extending convexly rounded cross-section.

  Predominantly axially, i.e. transversely oriented, the lateral portion of the transverse element is corrugated, in particular in the transverse direction, by being clamped between two conical pulleys of the pulley, It is frictionally coupled. The part of the side of the transverse element that engages the pulley pulley is called the contact surface. These contact surfaces extend substantially parallel to each other and are separated from each other over the (local) width of the transverse element.

  The frictional contact between the contact surface of the transverse element and the pulley sheave allows forces to be transmitted between them, which causes the drive belt to transmit drive torque and rotational movement from one pulley to the other. can do. The aforementioned contact surfaces of the transverse elements of the drive belt are such that the drive belt is brought into such frictional force-transmitting contact with the pulley sheaves and at the same time is displaced radially with respect to these sheaves. They are angled radially inward with respect to each other. This angle formed between the contact surfaces of the transverse elements is referred to as the contact angle of the belt, which contact angle exactly corresponds to the angle formed between the conical surfaces of the pulleys of the pulley. The latter angle is called the pulley angle.

  It is well known that when the drive belt and the pulley rotate during operation of the continuously variable transmission, the transverse element continuously and regularly collides with the pulley pulley to generate a sound. Such noise does not interfere with the correct operation of the transmission, but when the noise level of other sources is low, especially the vehicle engine, (meshing) gears or (rotating) wheels, (vehicle) driving. It may be felt uncomfortable by the hands. Therefore, the overall development objective in the design of continuously variable transmissions, especially drive belts used in continuously variable transmissions, is to minimize the noise generated by collisions during operation, at least for human hearing. is there.

  A definite measure to reduce the above-mentioned impact noise during transmission operation is to reduce the mass of the transverse element, thereby reducing the force of the transverse element's collision with the pulley sheave. As an alternative, according to EP-A-305023, a drive belt with two or more types of transverse elements of different thickness mixed in one another along the circumference of the belt is disclosed. Proposed to provide. This causes the transverse element to continuously impact the pulley at various intervals during transmission operation. The impact sound is thereby dampened by being distributed over two (or more) frequencies. However, the effects of this latter measure and / or the effects achievable by this latter measure are limited. This is because the difference in thickness between the various types of transverse elements is limited for both functional and manufacturing reasons. For example, the smoothness of operation of the transmission is best for the thinnest transverse elements, and the contact stress introduced by the transverse elements into the ring set is the least for the thinnest transverse elements. However, thicker transverse elements can reduce manufacturing costs and are generally stronger and less prone to wear than thinner transverse elements.

European Patent Publication No. 305023

  The present disclosure aims to provide a novel means of reducing the impulsive noise generated during operation, which means is not based on the above-mentioned modification of the thickness of the transverse element, which At least not necessarily.

  In particular, according to the present disclosure, two types of transverse elements are provided on the drive belt, of which the first type of transverse element has its respective front face or width in the vicinity of the front face, its respective back face or Wider than the width in the vicinity of the back surface, the second type of transverse element has a width in the vicinity of its respective back surface or back surface that is greater than its width in the vicinity of its respective front surface or front surface. However, the overall or nominal widths of the two types of transverse elements are not intended to be different, i.e. the frontal width of the first type transverse element and that of the second type transverse element. The widths of the back surfaces are approximately the same as each other, that is, they are the same within the variation or tolerance of the manufacturing method.

When the drive belt as defined in the above description is rotating in the transmission, the transverse element of the first type, when viewed in the rotational direction, impinges on the pulley disc in the vicinity of its front face, i.e. first contacting. However, in contrast, the second type of transverse element impinges on the pulley disc near its rear surface. As a result, three situations occur during operation:
1: The first type of transverse element is followed by a transverse element of the second type, in the direction of rotation described above, whereby a continuous collision of these transverse elements with the pulley discs of the respective pulleys. There is a relatively long (time) interval between;
2: The second type of transverse element is followed by a transverse element of the first type, which results in a relatively short distance between successive impacts of the transverse element with the pulley discs of the respective pulleys. ;
3: One of the two types of transverse element is followed by a transverse element of the same type, which results in an intermediate time between successive collisions of the transverse element with the pulley discs of the respective pulleys. A gap occurs.

  Due to the above-mentioned variation in the distance between successive collisions of two types of transverse elements, the noise generated by this successive collision is distributed in several frequencies, which results in an overall impact sound. Are advantageously damped, at least when recognized by the occupants of the vehicle in which the transmission is utilized. It is noted that, although only two types of transverse elements are utilized, three different time intervals are obtained during successive impacts of the transverse element with the operating pulley disc. As a result, the impact sound damping achieved thereby is generally more effective than that obtained with known drive belts which include two types of transverse elements of different thickness.

  In the following description, the novel drive belt design will be described in more detail along with one or more exemplary embodiments and with reference to the accompanying drawings.

FIG. 2 shows a schematic perspective view of a continuously variable transmission, in which a drive belt including an endless carrier and a plurality of transverse elements extends over two pulleys. 1 shows a cross-sectional view of a known drive belt oriented in the circumferential direction. 1 shows a transversely oriented view of a transverse element of a known drive belt. FIG. 3 shows a cross-sectional view of the lower part of a transverse element of a known drive belt, oriented in the width direction. FIG. 5 shows a cross-sectional view of the lower portion of a transverse element of the first type, in one embodiment according to the present disclosure, oriented in the width direction. FIG. 6A shows a cross-sectional view of a lower portion of a second type transverse element in one embodiment according to the present disclosure, in a widthwise direction. 3 represents a row of transverse elements including the aforementioned first and second types of transverse elements according to the present disclosure.

  In the drawings, like reference numbers indicate identical or equivalent structures and / or parts.

  The schematic diagram of the continuously variable transmission in FIG. 1 shows the drive belt 3. The drive belt 3 extends over the two pulleys 1, 2. The drive belt 3 comprises a flexible endless carrier 31 and mainly adjacent rows of transverse elements 32. The transverse elements 32 are attached to the circumference of the endless carrier 31 and are arranged along the circumference. In the illustrated transmission configuration, the upper pulley 1 rotates faster than the lower pulley 2. Varying the distance between the two conical pulleys 4, 5 of the pulleys 1, 2 to change the so-called running radius R of the drive belt 3 in each pulley 1, 2 in a coordinated manner. The result is that the (transmission) ratio between the rotational speeds of the two pulleys 1, 2 can be changed.

  FIG. 2 shows the drive belt 3 facing in the circumferential or lengthwise direction L of the belt 3, that is to say in the direction perpendicular to the axial or widthwise direction W of the belt 3 and the radius or height direction H. A cross-sectional view is shown. This FIG. 2 shows the presence of two endless carriers 31. The two endless carriers 31, which are shown in cross section in FIG. 2, support and guide a plurality of transverse elements 32 of the drive belt 3. One of them, the transverse element 32, is shown in front view in this FIG.

The transverse elements 32 of the drive belt 3 and the endless carrier 31 are typically made of metal, usually alloy steel. The transverse element 32 absorbs via its contact surface 37 the clamping force applied between the pulleys 4, 5 of each pulley 1, 2. One such contact surface 37 is provided on each axial side of the transverse element 32. These contact surfaces 37 extend radially outwardly from each other, whereby an acute angle is formed between the contact surfaces, which acute angle represents the contact angle Φ _C of the drive belt 3. ing. The contact angle approximately corresponds to the V angle formed between the pulleys 4, 5 of each pulley 1, 2, the latter angle representing the pulley angle Φ _P.

  The transverse element 32 is movable, i.e. slidable along the endless carrier 31 in the circumferential direction L, so that the transverse element 32 is endless in the direction of rotation of the drive belt 3 and the pulleys 1, 2. The torque can be transmitted between the transmission pulleys 1, 2 by pressing against each other along and along with each other. In the exemplary embodiment shown in FIG. 2, the endless carrier 31 is composed of each of five individual endless belts. These endless belts are concentrically provided in a nested manner to form an endless carrier 31. Indeed, the endless carrier 31 often comprises more than five, for example nine or twelve, or more practicable endless belts.

  The transverse element 32 of the drive belt 3, which is also shown in a side view in FIG. 3, is provided with two notches 33 located on opposite sides. Each of the notches 33 is open towards the respective axial side of the transverse element 32 and accommodates a (small section) of the respective endless carrier 31. Thus, the first portion or base 34 of the transverse element 32 extends radially inward from the endless carrier 31, and the second or central portion 35 of the transverse element 32 has these endless bodies. Located between the carriers 31, a third part or upper part 36 of the transverse element 32 extends radially outwardly from the endless carrier 31. The radially inner side of each notch 33 is defined by a so-called bearing surface 42 of the base 34 of the transverse element 32. The bearing surface 42 faces radially outward, usually in the direction of the upper part 36 of the transverse element 32, and contacts the inside of the endless carrier 31.

  One of the two body surfaces 38, 39 of the transverse element 32, which face in opposite circumferential directions L, is substantially flat. The body surface is hereinafter referred to as the back surface 39. A so-called locking edge 18 is provided on the body surface 38 or the front surface 38 opposite the transverse element 32. The locking edge 18 is between the upper part of the front face 38, which extends in the radial direction H substantially parallel to the rear face 39, and the lower part of the front face 38, which is inclined to extend toward the rear face 39. It forms a transition. In FIG. 2, the locking edge 18 is shown schematically by only one line, but in practice the locking edge 18 is usually provided in the form of a convexly curved transition surface. There is. Therefore, the aforementioned upper part of the transverse element 32 is provided with a substantially constant size between the front face 38 and the rear face 39 of the transverse element 32. That is, when viewed in the circumferential direction L, its dimension is typically referred to as the thickness of the transverse element 32.

  FIG. 4 shows a known transverse element 32 in a section along the line AA of the base 34 of the transverse element 32 shown in FIG. The front face 38 and the back face 39 are oriented substantially parallel, like the two contact faces 37 of the transverse element 32. Contact surface 37 is oriented substantially perpendicular to both front surface 38 and back surface 39. However, typically these surfaces 37-39 do not intersect at a sharp angle, instead a transition surface 43 is formed between them. The transition surface 43 forms a more rounded transition between the contact surface of the transverse element 32 and the front face 38 and the rear face 39, respectively.

  Based on these FIGS. 1 to 4, during operation of the transmission 1, i.e. during rotation of the pulleys 1, 2 and the drive belt 3 of the transmission, the transverse element 32 of the drive belt 3 is It is clear that when in frictional contact with the pulleys 1 and 2, the pulleys 4, 5 collide one after another. Such continuous collisions occur at a predetermined rotation speed of the drive belt 3 at regular intervals, and thus generate a sound of a specific wavelength or frequency. The sound represents an impact sound. In order to reduce the amplitude of such impulsive sounds, it is known in the art to randomly incorporate two different thickness transverse elements 32 into the drive belt 3 so that successive impacts occur at different intervals. Proposed. By this design measure, the impulsive sound is distributed between two distinct frequencies, which preferably reduces the amplitude of the impulsive sound.

  In this latter respect, it is noted that in typical transmission and drive belt designs, the total (perimeter) length of the belt has a value in the range of 500 mm to 750 mm. The transverse elements of such a typical drive belt design all have approximately the same width in the range between 24 mm and 30 mm when measured at the locking edge, and are likewise measured at the locking edge. In this case, they are provided with almost the same thickness in the range between 1.4 mm and 2.0 mm. In such a typical drive belt design, a thickness difference of no more than 0.14 mm to 0.20 mm is actually present between the various types of transverse elements incorporated in the drive belt to dampen impact noise. Can be achieved. With such a thickness difference of about 10% between the transverse elements of the drive belt, it is theoretically calculated that the frequency of collision of the transverse elements with the pulley sheaves is theoretically distributed over a range of at most about 200 Hz. You can

  Currently, alternative design measures are proposed to reduce the impact sound amplitude. In particular, it has been proposed to incorporate two types of transverse elements 32 in the drive belt 3. The first type I transverse element 32-I is shown schematically in FIG. 5 in cross section at the base 34 of the transverse element, the width of the respective front face 38 or in the vicinity of the front face 38 being the respective back face 39. Alternatively, it is wider than the width in the vicinity of the back surface 39. The second type II transverse element 32 is shown in FIG. 6 and has a respective back surface 39 or a width near the back surface 39 that is wider than a respective front surface 38 or a width near the front surface 38.

  A novel drive belt 3 incorporating both a first type I transverse element 32-I and a second type II transverse element 32-II is shown schematically in FIG. FIG. 7 shows a partial cross-sectional view of the base 34 of several continuous transverse elements 32-I, 32-II of the first and second type. FIG. 7 also shows the rotation direction RD of the drive belt 3.

  In FIG. 7, the rightmost transverse element 32-II, which is the second type II transverse element described above, first impinges on the pulley discs 4, 5 near the back surface 39 (position X1 in FIG. 7), On the other hand, the succeeding first type I transversal element 32-I described above first impinges on the pulley discs 4, 5 in the vicinity of the front face 38 (position X2 in FIG. 7). To do. These continuous collision positions X1 and X2 are located close to each other at a distance S that is approximately twice the range of the transition surface 43 described above. On the other hand, when the first type I transverse element 32 is followed or followed by the second type II transverse element 32-II in the rotational direction RD of the drive belt 3, the transverse element with the pulley discs 4, 5 The respective positions of impact X2, X3 of the are located relatively far apart, a distance L approximately corresponding to the combined thickness of the two transverse elements 32. Finally, two consecutive transverse elements 32-I, 32-II in the drive belt may each be the same type I, II transverse element, in which case the transverse element continuity with the pulley disks 4, 5 The respective positions X4, X5 or X6, X7 of the respective collisions are located at an intermediate distance M with respect to at least two other distances L and S.

  As a result of such a variation in the distances S, M, L between the positions X of the collisions of the successive transverse elements 32 of the drive belt 3 of the two types I, II, during operation of the drive belt 3, the pulley discs 4, Three different time intervals occur between successive impacts of each of the two type I, II transverse elements 32 with 5. This causes the noise generated by these successive collisions to be distributed among the three distinct frequencies, which preferably results in a lower overall collision sound amplitude.

  In addition to all the details of the foregoing specification and the accompanying drawings, the present invention relates to and includes all features of the appended claims. Reference signs in parentheses in the claims do not limit the claims, but are merely provided as non-binding examples in their respective features. The features recited in the claims may be applied separately to a given product or step, but in some cases may combine any two or more of the above features in the claims. It is also possible to apply.

  The invention described by this disclosure is not limited to the embodiments and / or examples explicitly described herein, but it is understood by those skilled in the art that modifications, changes and actual applications of the present disclosure, especially related arts. Includes what is within the reach of.

Claims (2)

The drive belt (3),
An endless carrier (31) and a plurality of continuous transverse elements (32),
Said transverse elements (32) are slidably arranged on said endless carrier (31), each transverse element (32) having one front face (38), one back face (39) and a plurality. A contact surface (37) of said transverse element (32) extending in the thickness direction between said front surface (38) and said back surface (39), said contact surface (37) In between, the transverse element (32) extends in the width direction, the transverse element (32) comprising a pulley pulley (1) of a transmission pulley (1, 2) to which the drive belt (3) can be applied. In the drive belt (3), which is set to come into contact with
The drive belt (3) comprises a rear surface of each of the transverse elements in the vicinity of a respective front surface (38) of the transverse element, due to the general inclination of the contact surface (37) of the transverse element (32). A transverse element (32-I) that is wider than the vicinity of (39), and a transverse element (32-I) that is wider near the respective back surface (39) of the transverse element than near the respective front surface (38) of the transverse element. characterized in that it comprises both a 32-II) and the drive belt.   2. The drive belt according to claim 1, wherein the transverse elements (32-I, 32-II) are included in the drive belt (3) in a random order.