JP6257524B2 - Drive belt for use in a continuously variable transmission comprising two types of transverse members having different widths - Google Patents

Description

  The present invention relates to a continuously variable transmission, that is, a drive belt used in a continuously variable transmission, and the drive belt is defined so as to be wound around two pulleys of the transmission. A plurality of individual transverse elements or transverse members contacting the transmission pulley and one or more endless supports for supporting the transverse members for the purpose of supporting and guiding these transverse members between the pulleys And a drive belt used in a continuously variable transmission. This type of drive belt is also known as a push belt.

  Each endless support of the drive belt typically consists of a plurality of continuous and flexible metal bands stacked on top of each other, also known as a ring set. Each endless support is at least partially inserted into a groove provided in the transverse member. In examples where the drive belt has only one endless support, such support is typically in a central groove of the transverse member that opens radially outward of the drive belt. It is assembled. However, the drive belt usually comprises at least two endless supports. These endless supports are each assembled in one of the two grooves of the transverse member. In this case, the groove is open towards the transverse member, i.e. to the side of the drive belt or to each side in the axial direction.

  The transverse members of the drive belt are arranged to slide along the circumferential direction of one or more endless supports in a substantially continuous row, whereby the transverse members are driven Forces related to belt movement can be transmitted. The transverse member has two main body surfaces. Both main body surfaces extend at least partially substantially parallel to each other and are separated from each other via the (local) thickness of the transverse member. The transverse member is relatively thin, so that several hundred transverse members are present in the drive belt, so that the subsequent rolling of the subsequent transverse members along the circumferential direction results from the relative rolling of the subsequent transverse members. The belt can be bent. The transverse member is intentionally brought into frictional contact with such a pulley by being clamped in the width direction between the two conical sheaves of the transmission pulley. The transverse member is brought into frictional contact mainly through the side face oriented in the axial direction, i.e. the width direction. This side is formed in a corrugated shape to accommodate transmission oil provided to the transmission to lubricate the frictional contact points.

  The frictional contact between the transverse member and the pulley sheave allows a force to be transmitted between them, which causes the drive belt to transmit drive torque and rotational movement from one transmission pulley to the other transmission pulley. Can be communicated to. Such transmission of mechanical force due to friction inevitably leads to energy loss due to elastic deformation of the member at the frictional contact point and / or heat generation at the frictional contact point. With regard to the latter, the unpublished Dutch patent application No. 1038910 includes both a transverse member that contacts the pulley sheave and a narrow member that does not contact the pulley sheave. It has been proposed to apply to one drive belt. As a result, only a part of the plurality of transverse members of the drive belt is actually pinched between the pulley sheaves, and the energy loss described above is reduced. Thus, the efficiency of torque transmission with this drive belt design is improved over known drive belts with equal width transverse members.

  In connection with the drive belt design described above, it opens up numerous possibilities for advantageous design changes of transverse members of different axial dimensions or widths, mainly for the purpose of reducing the manufacturing costs of the entire drive belt. It is recognized that.

  In the first aspect of the drive belt according to the present invention, only the wider transverse member has a corrugated side. Accordingly, the narrower transverse member is formed without such a corrugated portion. Such a corrugated surface, i.e., a smooth surface, can be easily and typically inexpensively formed in manufacturing compared to a corrugated surface.

  In the second aspect of the drive belt according to the present invention, the narrow transverse member is formed lower than the wide transverse member, i.e. has a small radial dimension. In particular, the narrow lateral member extends radially inwardly from the groove compared to the wide lateral member. Thus, preferably, less material is used in manufacturing, and preferably less weight is realized in the drive belt.

  In a first detail of the second aspect of the drive belt according to the present invention, the wide transverse member has a mainly constant thickness along substantially its entire radial dimension. Such a transverse member of constant thickness can be formed relatively easily and inexpensively in manufacturing.

  In this regard, conventional transverse members typically have a tapered bottom portion that extends radially inward while decreasing in thickness from below the groove. The transition formed between the upper part of the transverse member of at least a relatively constant thickness and the tapered bottom part of the transverse member thus formed is usually the main body surface of the transverse member And is often referred to as the tilted edge of the transverse member. This tilting edge allows adjacent lateral members of the drive belt to tilt relative to each other, thereby ensuring that they are reliably and clearly defined and remain in contact with each other. The drive belt can follow a curved track. In addition, the tilting edge is located in the radial direction and near the endless support, thereby minimizing efficiency loss due to friction between the endless support and the transverse member. ing.

  In this first detail of the second aspect of the invention, a wide transverse member is provided between the main body surface of the narrow transverse member and the bottom surface directed radially inward. Rolling contact with the bottom edge of the narrow transverse member. In order to facilitate such a design of the drive belt, in particular to minimize wear, the bottom edge of the narrow transverse member is preferably gently convex with a radius of curvature of, for example, 6 mm or more. It is rounded.

  Also in the third aspect of the drive belt according to the present invention, the wide transverse member has a mainly constant thickness substantially along its entire radial dimension. However, in this aspect, in order to enable relative tilting, the narrow transverse member is provided with tilting edges on both sides thereof, i.e. on both main body surfaces. In this third aspect, the design and manufacture of the wide transverse member can preferably be focused on and optimized for frictional contact with the transmission pulley. In contrast, the design and manufacture of narrow transverse members can preferably be concentrated on tilting contact with a wide transverse member provided on the drive belt and optimized for this tilting contact. can do.

  In a fourth aspect of the drive belt according to the present invention, the narrow transverse member and the wide transverse member are at least partially made of different materials. Thus, the material can preferably be optimized with respect to its respective friction or cost between the transverse members.

  In a first detail of the fourth aspect of the drive belt according to the present invention, the wide transverse member is at least partly provided with a nitrided surface layer or with a coating of wear-resistant material. By having it, it is made of a wear-resistant material compared to a narrow transverse member.

  In a second detail of the fourth aspect of the drive belt according to the present invention, for example, the narrow transverse member has a low friction coating so that the wide transverse member becomes a narrow transverse member. It is made of a material that gives a higher coefficient of friction than

  In a third detail of the fourth aspect of the drive belt according to the present invention, the narrow transverse member is a wide transverse member to compensate for wear and / or plastic deformation during operation of the drive belt. It is made of a material that imparts a higher coefficient of thermal expansion than

  In a fourth detail of the fourth aspect of the drive belt according to the present invention, the narrow transverse member is made of a lighter material compared to the wide transverse member. Since the narrow member is not clamped between the sheaves in the width direction, the narrow lateral member is not loaded as much as the wide lateral member. As a result, weak materials, which are typically also lighter compared to the materials used for wide transverse members, may be used for narrow transverse members.

  In the fifth aspect of the drive belt according to the present invention, the narrow lateral member is formed to be thicker or thinner than the wide lateral member. In this way, it is possible to optimize the number and distribution of wide, ie transverse members that contact the pulley sheave, and narrow, ie transverse members that do not contact the pulley sheave. For example, to reduce costs, it may be selected to apply a narrower transverse member formed thicker than a wider transverse member. Alternatively, the most robust drive belt design can be achieved if the narrow transverse member of the drive belt is made thinner than the wide transverse member of the drive belt. Further, by providing the drive belt with a narrow lateral member having a different thickness, noise generated during operation of the drive belt can be suitably reduced.

  The invention will be explained in more detail on the basis of the following description in conjunction with the drawings and preferred embodiments. In the drawings, like reference numbers indicate identical or similar structures and / or members.

It is a schematic perspective view of a continuously variable transmission provided with a drive belt that travels across two pulleys. 1 is a schematic view of a portion of a known drive belt having two sets of flexible rings and a plurality of transverse members. FIG. 5 is a schematic plan view of a part of a special design of the drive belt. 1 is a schematic front view of a first embodiment of a drive belt according to the present invention. It is a schematic front view of 2nd Embodiment of the drive belt which concerns on this invention. It is a schematic side view of the second embodiment of the drive belt according to the present invention. It is a schematic side view of the third embodiment of the drive belt according to the present invention. It is a schematic side view of the fourth embodiment of the drive belt according to the present invention. It is a schematic side view of the fifth embodiment of the drive belt according to the present invention.

  A drive belt 3 is shown in the schematic diagram of the continuously variable transmission, ie continuously variable transmission (CVT), shown in FIG. The drive belt 3 is wound around two pulleys 1 and 2 and has two separate endless supports 31 and a plurality of transverse members 30. These lateral members 30 are assembled side by side so as to be substantially adjacent to the endless support 31 in the circumferential direction, and are arranged along this circumferential direction. When the drive belt 3 is clamped between the two conical pulley sheaves 4 and 5 of the two pulleys 1 and 2, respectively, the drive belt 3 generates torque “T” between the pulleys 1 and 2. Can be transmitted to the other pulleys 2 and 1. At the same time, the running radius R of the drive belt 3 between the sheaves 4 and 5 of the pulleys 1 and 2 is the CVT (transmission) ratio “i”, that is, the ratio between the rotational speeds of the pulleys 1 and 2 Stipulate. CVT and its fundamental mode of operation are known per se.

  In FIG. 2, the drive belt 3 is shown in more detail in a plan view along the section of the three transverse members 30. As shown in FIG. 2, the endless support 31 is formed from a set of flat and flexible rings 32 that are stacked on each other. The transverse members 30 of the drive belt 3 are continuously arranged along the circumferential direction of the support 31 so that they can slide relative to the support 31 and in the circumferential direction of the support 31. ing. The lateral member 30 receives a clamping pressure applied between the sheaves 4 and 5 of the pulleys 1 and 2 via pulley contact surfaces 33 provided on both sides in the axial direction. The pulley contact surfaces 33 extend radially outward from one another and thereby substantially conform to the V-shaped angle defined between the two sheaves 4, 5 of each pulley 1, 2. The transition of the transverse member 30 between the radially outer part of constant thickness and the tapered radially inner part forms a so-called “tilted edge 34”. This shape of the transverse member 30 and the tilted edge 34 allow the drive belt 3 to follow a gently curved track.

  Hereinafter, the term “width W” is used in connection with the transverse member 30 and represents the maximum axial spacing between the pulley contact surfaces 33 thereof. In the known drive belt 3, all its transverse members 30 have a width W of approximately the same dimensions. In fact, such a width W is adjusted in accordance with a very narrow tolerance between the transverse members 30 of the drive belt 3, so that the mechanical load applied to the transverse member 30 during operation is reduced. It has come to be leveled.

As shown in FIG. 3, in the schematic plan view of the drive belt 3 or the view seen inward in the radial direction, the drive belt 3 includes a wider lateral member 30-I and a narrower lateral width. Direction member 30-II. Transverse member 30-I of the wide width, has a width W _I to receive a clamping pressure exerted through the pulley contact surfaces 33 between the sheaves 4, 5 of the pulleys 1 and 2, transverse member of narrow 30-II has a width _II that does not engage with the pulley sheaves 4, 5, at least not drivingly engaged or frictionally engaged. Both axial sides of the relatively narrow lateral member 30-II are simply referred to as side surfaces 35. This latter special design of the drive belt 3 improves the efficiency of force transmission by the CVT over the design of the conventional transverse member 30 of FIG. 2 having only the transverse members 30 of approximately the same width. be able to.

  The drive belt design of FIG. 3 opens up numerous possibilities for further optimization, especially with regard to reducing the manufacturing costs of the drive belt 3 as a whole.

  A first possible embodiment of the drive belt 3 according to the invention is shown in FIG. FIG. 4 is a front view of the left half of the relatively narrow lateral member 30-II disposed in front of the relatively wide transverse member 30-I. In the first embodiment, only the side surface 33 in the axial direction, that is, the pulley contact surface 33 of the wide transverse member 30-I includes the corrugated portion 36. The corresponding side surface 35 of the narrow transverse member 30-II is shaped as at least a relatively smooth surface.

  A second possible embodiment of the drive belt 3 according to the invention is shown in FIG. FIG. 5 shows a front view of the left half of the relatively narrow lateral member 30-II disposed in front of the relatively wide transverse member 30-I. In the second embodiment, the narrow transverse member 30-II is formed lower than the wide transverse member 30-I when viewed in the vertical direction in FIG. 5, that is, the wide transverse member 30-II is formed. Having a smaller radial dimension than the directional member 30-I, so that the narrow transverse member 30-II is removed from the support 31, ie, of the narrow transverse member 30-II. The groove 37 that accommodates the support 31 extends inward in the radial direction and is smaller than the extending length in the radial direction of the wide transverse member 30 -I. This second possible embodiment is further illustrated in FIG. 6 in a side view of five rows of transverse members 30, 30-I, 30-II.

  A third possible embodiment of the drive belt 3 according to the invention is shown in FIG. FIG. 7 shows a side view of five rows of the transverse members 30, 30-I, 30-II. In this third embodiment, in accordance with the second possible embodiment, in addition to the narrow transverse member 30-II formed lower than the wide transverse member 30-I, the wide width The transverse member 30-I additionally has a mainly constant thickness along its entire radial extension length. Accordingly, the wide lateral member 30-I does not have the tilted edge 34 described above, and instead, the narrow lateral member 30-II has two tilted edges 34, respectively. ing. One inclined edge portion 34 is provided on each main body surface of the narrow lateral member 30-II.

  A fourth possible embodiment of the drive belt 3 according to the invention is shown in FIG. FIG. 8 shows a side view of five rows of the transverse members 30, 30-I, 30-II. In this fourth embodiment, in accordance with the second possible embodiment, in addition to the narrow transverse member 30-II formed lower than the wide transverse member 30-I, the wide width Both the transverse member 30-I and the narrow transverse member 30-II additionally have a mainly constant thickness along their entire extension length. In this embodiment, the bottom edge 38 of the transverse member 30-II allows rolling contact with the adjacent transverse member 30 within the drive belt 3.

  A fifth possible embodiment of the drive belt 3 according to the invention is shown in FIG. FIG. 9 shows a side view of five rows of the transverse members 30-I and 30-II. In this fifth embodiment, in addition to the narrow transverse member 30-II formed lower than the wide transverse member 30-I, more consistent with the second possible embodiment, A thin and narrow transverse member 30-II and a thinner and narrower transverse member 30-II are provided on the drive belt 3.

  As will be apparent to those skilled in the art, the scope of the present invention is not limited to the embodiments described above, without departing from the scope of the present invention as defined in the following claims. Various modifications and changes of the above-described embodiment are possible.

Claims (5)

A drive belt (3), the drive belt (3) comprising an endless support (31) and a plurality of transverse members (30) slidably assembled to the endless support (31). Each of the transverse members (30) includes two main body surfaces and a groove, and the transverse member (30) extends in the thickness direction between the two main body surfaces. The endless support (31) is inserted into the groove, and the drive belt (3) is provided with at least two types (I, II) of transverse members (30) having different shapes. In the drive belt, the axial dimension or the maximum width (W _I ) of the first type (30-I) transverse member (30) is the second type (30-II) transverse direction. It is set larger than the maximum width (W _II ) of the member (30), and the second The lateral member (30) of type (30-II) has a radial dimension that is smaller than the radial dimension of the lateral member (30) of the first type (30-I). A drive belt characterized by A second type (30-II) transverse member (30) extends radially inward from the groove less than the first type (30-I) transverse member (30). The drive belt according to claim 1 . Drive belt according to claim 2 , wherein the transverse member (30) of the first type (30-I) has a constant dimension in the thickness direction along the entire surface comprising its main body surface. . The radially innermost bottom portion of the second type (30-II) transverse member (30) comprises a curved edge (38) having a radius of curvature of 6 mm or more on each side thereof. The drive belt according to claim 3 . The transverse member (30) of the second type (30-II) has convex curved portions (34) or tilted edges on both main body surfaces of the transverse member (30) below the groove. The drive belt according to claim 3 , wherein the drive belt is tapered inward in the radial direction.

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