Abstract:
A guiding device for guiding a belt of a belt-driven conical-pulley transmission. The device includes a first guiding section and a second guiding section that is spaced from the first guiding section, and between which the belt is guided in a running direction. The guiding sections have a longitudinal extent that corresponds to the running direction of the belt and a transverse extent that is perpendicular thereto, and lateral edge sections that delimit the guiding sections in the transverse direction. At least one guiding section has at least one longitudinal rib that extends in the longitudinal direction and that is positioned apart from the lateral edge sections in order to improve the guiding device structurally and functionally.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation of International Application Serial No. PCT/DE2012/000786, having an international filing date of 3 Aug. 2012, and designating the United States, the entire contents of which are hereby incorporated by reference to the same extent as if fully rewritten. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a guiding device for a belt means of a belt-driven conical-pulley transmission having a first guiding section and a second guiding section that is spaced from the first guiding section and between which the belt means can be guided in one running direction. The guiding sections have a longitudinal direction that corresponds to the running direction of the belt means and have a transverse direction perpendicular thereto, and lateral edge sections that delimit the guiding sections in the transverse direction. 
         [0004]    2. Description of the Related Art 
         [0005]    From WO 2007/068229 A1 a guiding arrangement for a belt means is known, having at least one guiding device which includes at least two corresponding guide tongues between which the belt means is at least partially guided, the guide tongues being held at a predetermined distance from each other by means of a connecting region, at which during temperature changes the distance between the guide tongues is approximately constant, due to the use of materials having differing heat expansion coefficients in the guiding device, in order to keep the distance between the guide tongues approximately constant, independent of temperature fluctuations. According to WO 2007/068229 A1, essentially a synthetic material having a high heat expansion coefficient is intended as the material of the guiding device, and at least the connecting region of the guiding device includes at least one element made of a material having a lower heat expansion coefficient, such as a U-shaped metal bow. 
         [0006]    An object of the present invention is to structurally and/or functionally improve a guiding device of the type identified at the beginning. 
       SUMMARY OF THE INVENTION 
       [0007]    The object is achieved with a guiding device for a belt means of a belt-driven conical-pulley transmission. The guiding device includes a first guiding section and a second guiding section which is spaced apart from the first guiding section, between which guiding sections the belt means can be guided in one running direction. The guiding sections have a longitudinal direction that corresponds to the running direction of the endless torque-transmitting belt means, and a transverse direction perpendicular thereto, and lateral edge sections which delimit the guiding sections in the transverse direction, wherein at least one guiding section has at least one longitudinal rib which extends in the longitudinal direction, which is positioned spaced from the lateral edge sections. 
         [0008]    The transmission ratio of the belt-driven conical-pulley transmission can be continuously adjustable. The belt-driven conical-pulley transmission can be a continuously variable transmission (CVT). The belt-driven conical-pulley transmission can be a variator transmission. The belt-driven conical-pulley transmission can be positioned in a drivetrain of a motor vehicle. The belt-driven conical-pulley transmission can have a first conical pulley and a second conical pulley. The conical pulleys can have parallel axes of rotation. Each pulley can have one axially fixed conical disk and one axially movable conical disk. It can be possible to move the axially movable conical disks of the conical pulleys in opposite directions. It can be possible to drive the first conical pulley by means of an input drive. The input drive can be an internal combustion engine. It can be possible to connect an output drive by means of a second conical pulley. The endless torque-transmitting means can serve to transmit mechanical power between the first conical pulley and the second conical pulley. The belt-driven conical-pulley transmission can have a housing. The conical disks can be supported in the housing. 
         [0009]    The belt means can be a traction medium. The belt means can be a chain. The chain can be a plate-link chain. The chain can have plates and pressure members. The pressure members can serve to couple the belt means with the conical pulleys. A coupling between the pressure members and the conical pulleys can occur by frictional engagement. The plates can serve to couple the pressure members. The belt means can have a tight side under tension and a slack side. In operation, vibrations in a transverse direction can be induced on the tight side and/or on the slack side of the belt means. The transverse direction can be a direction that is perpendicular to the running direction of the belt means and perpendicular to the axes of rotation of the conical pulleys. The belt means can have a running position independent of a transmission ratio of the belt-driven conical-pulley transmission. The running position of the belt means can change with a change in the transmission ratio of the belt-driven conical-pulley transmission. 
         [0010]    With the guiding device, it can be possible to guide the belt means on a tight side. With the guiding device, it can be possible to guide the belt means on a slack side. It can be possible to guide the belt means at the first guiding section and at the second guiding section in a transverse direction. It can be possible to guide the belt means at least nearly free of clearance between the first guiding section and the second guiding section. The belt means can slip in operation at the first guiding section and/or at the second guiding section. At the first guiding section, it can be possible to guide the belt means by its inner side. An inner side of the belt means can be a side facing the axes of rotation of the conical pulleys. At the second guiding section, it can be possible to guide the belt means by its outer side. An outer side of the belt means can be a side facing away from the axes of rotation of the conical pulleys. 
         [0011]    The first guiding section and the second guiding section can be connected to each other by means of a connecting section. The connecting section can be positioned on a lateral edge section of the first guiding section and on a lateral edge section of the second guiding section. The lateral edge sections can delimit the guiding sections in a transverse direction. The first guiding section, the second guiding section, and the connecting section can be produced in a single piece. The connecting section can have reinforcing ribs. The connecting section can have an upper, a lower, and lateral edge sections. The reinforcing ribs can be positioned on at least one edge section of the connecting section. There can be reinforcing ribs positioned between the edge sections of the connecting section. Diagonally-running reinforcing ribs can be positioned between the edge sections of the connecting section. A ring-shaped reinforcing rib can be positioned between the edge sections of the connecting section. 
         [0012]    The longitudinal rib can be positioned inwardly of the connecting section in a transverse direction. A transverse direction can be a direction corresponding to the direction of the axes of rotation of the conical pulleys. The longitudinal rib can be at least approximately centered between the edge sections in a transverse direction. The longitudinal rib can be positioned off-center in a transverse direction. The guiding device can be divided in the longitudinal direction into two guiding device halves. The guiding device halves can be connected to each other. The guiding device halves can be connected to each other positively. The guiding device halves can be locked together. A guiding section can be divided in the longitudinal direction into two guiding section halves. Each guiding section half can have edge sections which delimit movement of the belt means in a transverse direction. Each guiding section half can have a longitudinal rib. The longitudinal rib of each guiding section half can be positioned apart from the edge sections of that guiding section half. The longitudinal rib of each guiding section half can be positioned inside in a transverse direction on the guiding section half. The longitudinal rib of each guiding section half can be positioned in a transverse direction at least approximately centered between the edge sections of the guiding section half. The longitudinal rib of each guiding section half can be positioned in a transverse direction, off-center and between the edge sections of the guiding section half. 
         [0013]    The guiding device in accordance with the invention has increased stability. Area moment of inertia is increased. Bending stiffness is increased. Inherent stiffness is increased. The guiding device in accordance with the invention makes improved damping of vibrations of the belt means possible. Noise development when the transmission is in operation is reduced. Wear of the belt means is reduced. Additional construction space is not required. 
         [0014]    The at least one guiding section can have a guide tongue and an outer panel spaced from the guide tongue, and the longitudinal rib can extend between the guide tongue and the outer panel. The guide tongue and the outer panel can be spaced from each other in a vertical direction of the guiding device. A vertical direction can be a direction that is perpendicular to the running direction of the endless torque-transmitting means and to the axes of rotation of the conical pulleys. A vertical direction can correspond to a transverse direction. The belt means can be guidable by slipping in contact on the surface of the guide tongue. The guide tongue and the outer panel can be positioned at least nearly parallel to each other. The guide tongue and the outer panel can be spaced farther apart from each other in a middle section of the guiding section than at end sections of the guiding section. The guide tongue and the outer panel can merge into each other at end sections of the guiding section. The longitudinal rib can extend between the guide tongue and the outer panel in a vertical direction of the guiding section. The guide tongue, the outer panel, and the longitudinal rib can form a double-T profile-like cross section of the at least one guiding section. Thereby, the at least one guiding section has a high area moment of inertia. 
         [0015]    The at least one guiding section can have at least one transverse rib. The transverse rib can extend in a transverse direction of the guiding section. The transverse rib can extend in a vertical direction of the guiding section, thereby achieving an additional increase in stability. A plurality of transverse ribs can be positioned along the at least one guiding section. A plurality of transverse ribs can be distributed in the longitudinal direction of the guiding section. The transverse ribs can be positioned at least approximately at the same distance from each other. The transverse ribs can be distributed at least approximately symmetrically. That achieves an adjusted stability over the length of the guiding section. 
         [0016]    The guide tongue, the outer panel, the longitudinal rib and/or the transverse rib(s) can be of an at least approximately equal material thickness. That improves producibility, for example in an injection molding process. The guiding device can be made of a single material. The material can be a sheet metal material. The material can be a synthetic material. The synthetic material can have a filler. A hybrid construction can be avoided. 
         [0017]    In summary, and stated in other words, the invention provides, among other things, a torsionally stiff guide rail of a double T-beam design. 
         [0018]    Chain vibrations in the region between the pulleys (tight side, slack side) can be hindered from vibrating by the guide rails, which minimizes noise formation. One factor in this can be the rigidity of the guide rail tongues. Due to the available construction space, both on the inner side because of the disk geometry and on the outer side because of the housing, a form of the tongues can be severely restrictedly “specified.” 
         [0019]    Flexural rigidity/dimensional stability can be derived from the modulus of elasticity (E) and the area moment of inertia (I). An increase in the flexural rigidity can be achieved with an I-profile, possibly supported by additional transverse ribs orthogonal to longitudinal ribs and to the inner guide rail tongue. Through that geometric measure, it is possible, for example, to eliminate the use of additional elements, such as metal leaf springs. 
         [0020]    The guide rail can have an I-profile (double T-beam). The longitudinal rib can be positioned in the direction of the tongue center. In addition, a tongue can be provided corresponding to a contour of the outer guide rail tongue/sliding surface corresponding to a maximum available outer contour. Transverse ribs, which are connected to both the first and the second outer ribs and serve to counteract twisting, can be provided on both sides of the longitudinal rib. 
         [0021]    Exemplary embodiments of the present invention will be described in greater detail below in reference to the accompanying drawing figures. That description will provide additional features and advantages. Concrete features of the exemplary embodiments can depict general features of the invention. Features of the exemplary embodiments combined with other features can also represent individual features of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The drawing figures show the following, schematically and by way of example: 
           [0023]      FIG. 1  is a side view of a continuously adjustable transmission having two conical pulleys, a chain, and a guide rail to guide the chain, 
           [0024]      FIG. 2  is a side view of one guide rail half of a two-part guide rail, having two guiding sections and one connecting section, viewed in the inner direction of the guide rail, 
           [0025]      FIG. 3  is an outer, longitudinal side view of one guide rail half of a two-part guide rail, partially in section, having two guiding sections and one connecting section, 
           [0026]      FIG. 4  is a transverse cross-sectional view of one guide rail half of a two-part guide rail having two guiding sections and one connecting section, 
           [0027]      FIG. 5  is a longitudinal cross-sectional view of one guide rail half of a two-part guide rail having two guiding sections and one connecting section. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0028]      FIG. 1  shows a side view of a continuously adjustable transmission  100  having two conical pulleys  102 ,  104 , a chain  106 , and a guide rail  108  to guide the chain  106 . 
         [0029]    The conical pulley  102  includes two conical disks and can be driven starting from a motor vehicle internal combustion engine. An axis of rotation of the conical pulley  102  is identified as  110 . The direction of arrow a shows a direction of drive rotation. The conical pulley  104  can be suitably drive-connected to driving wheels of the motor vehicle. An axis of rotation of the conical pulley  104  is identified as  112 . 
         [0030]    The chain  106  serves to transmit mechanical power between the conical pulley  102  and the conical pulley  104 . In the figure, the chain  106  runs on a small radius on the conical pulley  102  and on a large radius on the conical pulley  104 . That results in a transmission ratio change of the transmission in the slower direction in the present case. 
         [0031]    One of the conical disks of each of the conical pulleys  102 ,  104  can be moved in the direction of the respective axes of rotation  110 ,  112  relative to the respective other conical disk. If the conical disks of a conical pulley  102 ,  104  are far apart from each other, the chain  106  runs at a small radius of the associated conical pulley. If the conical disks of a conical pulley  102 ,  104  have a small distance between them, the chain  106  runs at a large radius of the associated conical pulley. If the distance between the conical disks is increased, the running radius of the chain  106  shifts in the direction of smaller radii. If the distance between the conical disks is decreased, the running radius of the chain  106  shifts in the direction of larger radii. The axially movable conical disks of the conical pulleys  102 ,  104  are adjusted in opposite directions, so that the chain  106  remains pre-tensioned. When the transmission ratio of the transmission  100  is changed, the relative position between the chain  106  and the axes  110 ,  112  of the conical pulleys  102 ,  104  changes. 
         [0032]    With an input torque corresponding to the direction of arrow a, the chain  106  runs in the direction of arrow b along guide rail  108 . The guide rail  108  is then positioned on a tight side of the chain  106 . The guide rail  108  has an inner guiding section  114  and an outer guiding section  116 . The guiding sections  114 ,  116  are connected to each other by connecting sections, such as  118 . The chain  106  is guided between the guiding sections  114 ,  116  with only a small clearance. The guide rail  108  is positioned on a support tube  120 . The support tube  120  is firmly positioned on a housing (not shown) of the transmission  100 , and thus it is fixed in relation to the axes  110 ,  112  of the conical pulleys  102 ,  104 . For the support of guide rail  108  on the support tube  120 , the guide rail  108  has a receptacle in the form of a U-shaped opening. 
         [0033]    During operation of the transmission  100 , vibrations can be induced in chain  106  in a transverse direction to the chain movement direction, as shown by arrow c. The-U-shaped opening of the receptacle of the guide rail  108  extends in the direction of arrow c. To enable a change in the position of the chain  106  relative to axes  110 ,  112  when the transmission ratio of the transmission  100  changes, the guide rail  108  is situated on the support tube  120  so that it can pivot around the longitudinal axis of the support tube  120 , and so that it is movable in the direction of arrow c. 
         [0034]    The guide rail  108  is composed of two guide rail halves. The two guide rail halves are fitted together in the direction of the axes of rotation  110 ,  112 . A split plane of the guide rail  108  extends in the running direction of the chain  106  represented by arrow b, as well as in the transverse direction of arrow c. 
         [0035]      FIG. 2  shows a guide rail half  200  of a two-part guide rail, like guide rail  108  shown in  FIG. 1 , having two opposed, spaced guiding sections  202 ,  204  and a connecting section  206 , as viewed from inside the guide rail. The guiding sections  202 ,  204  are kept apart from each other by the connecting section  206 . The connecting section  206  is narrower at its end assigned to the guiding section  202  than at its end assigned to the guiding section  204 . With its inner surface the connecting section  206  defines a lateral guide surface for the chain. 
         [0036]    The guiding section  202  serves to guide the inner surfaces of a chain, such as chain  106  shown in  FIG. 1 . The guiding section  204  serves to guide the outer surfaces of the chain. The guiding section  202  has a sliding surface on tongue  208 . A receptacle  210  for engagement with a support tube, such as support tube  120  shown in  FIG. 1 , is positioned on the guiding section  202 . The guiding section  204  has a sliding surface on tongue  212 . The sliding surface of tongue  208  of the guiding section  202  and the sliding surface of tongue  212  of the guiding section  204  are positioned parallel to each other. The guiding section  204  has an outer panel  214 . The outer panel  214  and the sliding surface of tongue  212  are spaced from each other. The outer panel  214  is spaced farther apart from the sliding surface of tongue  212  in a middle section than at end sections of the guiding section  204 . At the outer ends of guiding section  204 , the outer panel  214  and the sliding surface of tongue  212  merge into each other. Otherwise the middle section of outer panel  214  and the sliding surface of tongue  212  are positioned parallel to each other. 
         [0037]    Positioned between the sliding surface of tongue  212  and the outer panel  214  is a longitudinal rib  216 . The longitudinal rib  216  extends between the outer end sections of the guiding section  204  and the outer panel  214 . The longitudinal rib  216  is positioned at right angles to the sliding surface of tongue  208  and at right angles to the outer panel  214 . Extending transversely to the longitudinal rib  216 , the guiding section  204  has transverse ribs, such as ribs  218 ,  220 ,  222 . The transverse ribs  218 ,  220 ,  222  are positioned between the sliding surface of tongue  212  and the outer panel  214 . 
         [0038]    The guide rail half  200  has a locating pin  224 , a locating pin receptacle  226 , a locking hook  228 , and a locking bow  230  to allow guide rail half  200  to connect with a mating second guide rail half to form a complete guide rail. The guide rail half  200  is made in one piece. The guide rail half  200  is made of a synthetic material, for example a polyamide, possibly with a glass fiber filling. The guide rail half  200  is made in an injection molding process. 
         [0039]      FIG. 3  shows a guide rail half  300  of a two-part guide rail, like guide rail  108  shown in  FIG. 1 , having two guiding sections  302 ,  304  and a connecting section  306 , viewed from outside. On the outer side the connecting section  306  has ribs  308 ,  310 ,  312 ,  314  running on its edge sections, as well as diagonally-running ribs  316 ,  318 , and a ring-shaped rib  320 . Otherwise see  FIG. 2  and the associated description. 
         [0040]      FIG. 4  shows a cross-sectional view of a guide rail half  400  of a two-part guide rail, like guide rail  108  shown in  FIG. 1 , having two spaced guiding sections  402 ,  404  and a connecting section  406 . The sliding surface of tongue  408  of the guiding section  404  has edge sections  410 ,  412  which delimit the width of sliding surface of tongue  408  in the transverse direction of the guide rail. The outer panel  414  of the guiding section  404  has edge sections  416 ,  418  which delimit the outer panel  414  in the transverse direction of the guide rail. The longitudinal rib  420  is positioned between the edge sections  410 ,  412 ,  416 ,  418 , lying inside in the transverse direction of the guide rail. The connecting section  406  connects the edge section  410  of guiding section  404  and an edge of guiding section  402 . A transverse rib  422  is visible in  FIG. 4 . The transverse rib  422  extends between the edge sections  410 ,  416  of guiding section  404  and the edge sections  412 ,  418  of guiding section  404 . Otherwise see  FIGS. 2 and 3  and the associated description. 
         [0041]      FIG. 5  shows a longitudinal cross section of a guide rail half  500  of a two-part guide rail, like guide rail  108  shown in  FIG. 1 , having two opposed guiding sections and a connecting section  502 . A tongue  504  of a guiding section  506  is visible in  FIG. 5 . The cut line of the sectional view shown in  FIG. 5  runs through the longitudinal rib  508  and the transverse ribs, such as ribs  510 ,  512 ,  514 . Also shown in  FIG. 5  is a locating pin  516 , a locking bow  518 , and a locking hook  520 , each for engagement with associated elements of the other half of the two-part guide rail, such as those shown in  FIG. 2 . Otherwise see  FIGS. 2 ,  3 , and  4  and the associated description.