Patent Publication Number: US-10774572-B2

Title: Opening-closing body driving device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a National Stage application of International Patent Application No. PCT/JP2017/002640, filed on Jan. 26, 2017, which claims priority to Japanese Patent Application No. 2016-046726 filed on Mar. 10, 2016, each of which is hereby incorporated by reference in its entirety. 
     TECHNICAL FIELD 
     The present invention relates to an opening-closing body driving device that drive an opening-closing body for opening and closing an opening portion. 
     BACKGROUND ART 
     Heretofore, in a vehicle such as a minivan or an estate car (so-called one-box car), a sliding door (opening-closing body) that slides in a front-rear direction of the vehicle is provided on a side portion of a vehicle body. This allows getting on and off the vehicle or loading and unloading of a burden to be carried out easily from a large opening portion that is formed on the side portion of the vehicle body. Since weight of the sliding door is heavy, a power sliding door device capable of automatically opening and closing the sliding door is mounted on the vehicle. 
     In the power sliding door device, one end of a cable the other end of which is connected to the sliding door from a front-rear direction of the vehicle is introduced to a driving unit via inversion pulleys provided at both ends of a guide rail fixed to a vehicle body. The one end of the cable is wound around a drum of the driving unit. By rotating the drum by means of a motor, the sliding door is pulled by the cable to open and close the opening portion. 
     In the cable type power sliding door device as described above, the sliding door is guided by a curved portion of the guide rail and is drawn into the inside of the vehicle body by strong force. For this reason, the cable extends due to long-term usage, whereby a path length of the cable gets elongated. For example, in a driving unit described in Patent Document 1, in order to absorb change in the path length of a cable, a pair of tensioner mechanisms is provided in a case so as to correspond to open-side and close-side cables. This causes predetermined tension to be applied to each of the cables, thereby eliminating slack of each of the cables. 
     RELATED ART DOCUMENTS 
     Patent Documents 
     
         
         Patent Document 1: Japanese Patent Application Publication No. 2011-074657 
       
    
     SUMMARY 
     In the driving unit described in Patent Document 1, a flat roller is adopted as a pulley constituting the tensioner mechanism. Specifically, a cylindrical guide surface (flat surface) is provided on an outer periphery of the pulley, and flange portions are respectively formed at both sides thereof in an axial direction in order to prevent the cable to drop off from the guide surface. Each of these flange portions projects outward in a radial direction of the pulley from the guide surface, and has a diameter larger than that of the guide surface. A corner with a roughly right angle is formed at a side of the guide surface of each of the flange portions. 
     However, in the driving unit described in Patent Document 1, a film made of resin is formed outside the cable in the radial direction to smoothen movement of the cable. A problem may occur that the film is strongly pressed to a corner of the flange portion to damage it and this causes durability of the cable to be deteriorated. 
     It is an object of the present invention to provide an opening-closing body driving device capable of improving durability of a cable. 
     In one aspect of the present invention, there is provided an opening-closing body driving device configured to drive an opening-closing body for opening and closing an opening portion. The opening-closing body driving device includes: a case; a drum having a spiral guide groove on an outer periphery of the drum, the drum being configured to be accommodated in the case; a cable, one end of the cable being wound in the guide groove, the other end of the cable being connected to the opening-closing body; a cable entrance portion provided on the case, the cable going in and out of the case from the cable entrance portion; a pulley holder provided between the drum in the case and the cable entrance portion, the pulley holder including a pulley shaft; a pulley provided rotatably around the pulley shaft and movably in an axial direction of the pulley shaft, the pully including a pulley groove on which the cable is wound; flange portions provided at both sides of the pulley in the axial direction, each of the flange portions preventing the cable to drop off from the pulley groove; and a spring member accommodated in the case, the spring member being configured to press the pulley holder in such a direction that a path length between the drum and the cable entrance portion is increased. In this case, a cross-sectional shape of the cable is formed into a round shape, and a cross-sectional shape of a connecting unit between the pulley groove of the pulley and each of the flange portions is formed into a circular arc shape. 
     In another aspect of the present invention, a cross-sectional shape of the pulley groove is formed into a circular arc shape, and a radius dimension of the pulley groove is a dimension is equal to or larger than a diameter dimension of the cable. 
     In still another aspect of the present invention, the pulley holder includes: a pair of support walls that respectively supports both sides of the pulley shaft in an axial direction, and controls movement of the pulley in the axial direction; a connecting wall disposed outside the pulley in a radial direction of the pulley to connect the pair of support walls to each other; a projecting portion provided on the connecting wall, the projecting portion projecting outside the pulley in the radial direction; a passing path provided inside the projecting portion to allow a locking block to pass through the passing path, the locking block being provided at one end of the cable; and a slit provided inside the projecting portion in the radial direction to guide winding of the cable from the passing path to the pulley groove. 
     In still another aspect of the present invention, a width dimension of the slit is set to a dimension by which the cable is allowed to pass through the slit and controls passage of the locking block. 
     In still another aspect of the present invention, a taper portion is formed between the passing path and the slit, the taper portion being configured to guide movement of the cable from the passing path to the slit. 
     In still another aspect of the present invention, the projecting portion is disposed at a central part of the connecting wall along the axial direction of the pulley shaft, and a clearance dimension between the slit and the connecting unit is a dimension larger than a clearance dimension between the slit and the flange portion in a state where the pulley comes into contact with the support wall. 
     In still another aspect of the present invention, the pulley is provided swingably with respect to the pulley shaft. 
     According to the present invention, a cross-sectional shape of a cable is formed into a round shape, and a cross-sectional shape of a connecting unit between a pulley groove of a pulley and a flange portion is formed into a circular arc shape. Thus, it is possible to surely suppress damage of the cable caused by being strongly pressed to a corner as a conventional manner. Therefore, it is possible to improve durability of the cable, whereby it is possible to extend a maintenance cycle of an opening-closing body driving device and obtain high reliability thereof. 
    
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         FIG. 1  is a side view of minivan. 
         FIG. 2  is a plan view showing an assembling structure of a sliding door onto a vehicle body. 
         FIG. 3  is a front view showing an outline of a driving unit (without a cover). 
         FIG. 4  is a perspective view showing details of a drum. 
         FIG. 5  is a perspective view showing a locking block that is fixed to a cable. 
         FIG. 6  is a perspective view showing details of an open-side tensioner mechanism shown in  FIG. 3 . 
         FIG. 7  is a perspective view when the tensioner mechanism of  FIG. 6  is viewed from a direction of an arrow A. 
         FIG. 8  is a cross-sectional view taken along a B-B line of  FIG. 7 , which passes through a pulley shaft. 
         FIGS. 9( a ) and 9( b )  are explanatory drawings for explaining a moving state of a pulley in an axial direction with respect to the pulley shaft. 
         FIGS. 10( a ), 10( b ), and 10( c )  are explanatory drawings for explaining a winding procedure of the cable to a pulley groove. 
         FIGS. 11( a ), 11( b ) and 11( c )  are explanatory drawings for explaining that the cable is not dropped off from the pulley groove. 
         FIG. 12  is a cross-sectional view showing a periphery of a pulley in a tensioner mechanism according to a second embodiment. 
         FIG. 13  is a cross-sectional view corresponding to  FIG. 8  that shows a tensioner mechanism according to a third embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, a first embodiment according to the present invention will be described in detail with reference to the accompanying drawings. 
     First Embodiment 
       FIG. 1  shows a side view of a minivan or an estate car (so-called one-box car).  FIG. 2  shows a plan view an assembling structure of a sliding door to a vehicle body.  FIG. 3  shows a front view showing an outline of a driving unit (without a cover).  FIG. 4  shows a perspective view showing details of a drum.  FIG. 5  shows a perspective view showing a locking block that is fixed to a cable. 
     As shown in  FIG. 1 , a vehicle  10  is a minivan. A relatively large opening portion  12  is provided in a side portion of a vehicle body  11  that forms the vehicle  10 . Further, a sliding door (that is, an opening-closing body)  13  is provided on the side portion of the vehicle body  11 . The sliding door  13  is configured to open and close the opening portion  12 . As shown in  FIG. 2 , the sliding door  13  includes a roller assembly  13   a . The roller assembly  13   a  is configured to move along a guide rail  14  fixed on the side portion of the vehicle body  11 . 
     When the roller assembly  13   a  moves along the guide rail  14 , the sliding door  13  also moves along the side portion of the vehicle body  11 . Specifically, the sliding door  13  is configured to move in a front-rear direction of the vehicle  10  between a “fully closed state” position indicated by a solid line in  FIG. 1  and  FIG. 2  and a “fully opened state” position indicated by a two-dot chain line in  FIG. 1  and  FIG. 2 , thereby opening and closing the opening portion  12 . Here, as shown in  FIG. 2 , a drawing portion  14   a  is provided at a portion of the guide rail  14  in a front side of the vehicle  10 . The drawing portion  14   a  is curved toward the inside of a vehicle interior (upper side in  FIG. 2 ). Thus, by guiding the roller assembly  13   a  toward the drawing portion  14   a , the sliding door  13  blocks or closes the opening portion  12 , and is stored in the same plane with respect to a side surface of the vehicle body  11 . 
     As shown in  FIG. 1 , the roller assembly  13   a  and the guide rail  14  are provided at each of upper and lower portions (upper part and lower part) of the sliding door  13  in the front side of the vehicle  10  in addition to a central portion of the vehicle body  11  along up-and-down direction. Namely, the sliding door  13  is openably and closably supported at total three portions with respect to the vehicle body  11 . 
     As shown in  FIG. 2 , a power sliding door device  20  is mounted on the vehicle  10 . The power sliding door device  20  is configured to automatically open and close the sliding door  13 . The power sliding door device  20  is a cable type operating apparatus for open and close, and includes a driving unit  21 , an open-side cable  22   a , and a close-side cable  22   b . The driving unit  21  is disposed in the vehicle interior of the vehicle body  11  and roughly at a central part of the guide rail  14  along the front-rear direction of the vehicle  10 . Further, each of the open-side cable  22   a  and the close-side cable  22   b  has a function to transmit power of the driving unit  21  to the sliding door  13 . 
     The open-side cable  22   a  is introduced to the roller assembly  13   a  from a rear side of the vehicle  10  via a first inversion pulley  23   a . The first inversion pulley  23   a  is placed at a rear side of the guide rail  14  in the vehicle  10 . The open-side cable  22   a  is configured to pull the sliding door  13  to an open side in this manner. On the other hand, the close-side cable  22   b  is introduced to the roller assembly  13   a  from the front side of the vehicle  10  via a second inversion pulley  23   b . The second inversion pulley  23   b  is placed at a front side of the guide rail  14  in the vehicle  10 . The close-side cable  22   b  is configured to pull the sliding door  13  to a close side in this manner. 
     One end of each of the open-side cable  22   a  and the close-side cable  22   b  is introduced to the inside of the driving unit  21 . When the open-side cable  22   a  is wound up by the driving unit  21 , the sliding door  13  is pulled by the open-side cable  22   a  to automatically carry out an opening operation. On the other hand, when the close-side cable  22   b  is wound up by the driving unit  21 , the sliding door  13  is pulled by the close-side cable  22   b  to automatically carry out a close operation. 
     As shown in  FIG. 3 , the driving unit  21  includes a case  30  made of resin material such as plastics. The case  30  also functions as a frame for supporting each of members and/or mechanisms that constitute the driving unit  21 . The driving unit  21  is fixed to the vehicle body  11  (see  FIG. 2 ) by bolts or the like (not shown in the drawings) via four fixing portions FP provided on the case  30 . Here, the driving unit  21  constitutes an opening-closing body driving device according to the present invention. 
     An electric motor (motor)  31  is provided on the case  30 . The electric motor  31  becomes a driving source of the driving unit  21 . A flat-shaped brushless motor is adopted as the electric motor  31 . The brushless motor can rotate in forward and reverse directions. This makes it possible to suppress a thickness dimension of the driving unit  21  from being increased. A decelerating mechanism (not shown in the drawings) is provided in the vicinity of the electric motor  31  and inside the case  30 . The decelerating mechanism is made up by a planetary gear reducer. This allows rotational speed of the electric motor  31  to be reduced, whereby rotational power of an output shaft  32  becomes high torque. 
     Further, an electromagnetic clutch (not shown in the drawings) is provided between the decelerating mechanism and the output shaft  32 . When the sliding door  13  (see  FIG. 2 ) is manually operated to be opened and closed, this electromagnetic clutch is opened to shut off a power transmission route between the decelerating mechanism and the output shaft  32 . This makes it possible to operate smoothly opening and closing the sliding door  13  by a small load. 
     As shown in  FIG. 3 , a drum housing chamber  30   a  formed into a roughly cylindrical shape is provided at a roughly central portion of the case  30 . The drum housing chamber  30   a  is coaxially disposed with respect to the electric motor  31 . A driving drum (drum)  33  is accommodated rotatably in the inside of the drum housing chamber  30   a.    
     As shown in  FIG. 4 , the driving drum  33  is formed into a roughly columnar shape, and includes a spiral guide groove  33   a  on an outer periphery thereof. The driving drum  33  is fixed to the output shaft  32  at a shaft center thereof. The output shaft  32  projects to the drum housing chamber  30   a . This causes the driving drum  33  to be rotatively driven by the electric motor  31 , whereby the driving drum  33  rotates in forward and reverse directions inside the drum housing chamber  30   a . Note that the driving drum  33  and the output shaft  32  undergo serration engagement with each other, whereby they integrally rotate surely without sliding with each other. 
     One end of the open-side cable  22   a  introduced to the driving unit  21  is wound along the guide groove  33   a  from one side of the driving drum  33  in an axial direction. Further, as shown in  FIG. 5 , a locking block  34  made of metal is rigidly fixed to one end of the open-side cable  22   a  by means of calking or the like. The locking block  34  is formed into a roughly square pole shape. The locking block  34  is locked into a locking hole  33   b  that is provided on one side surface of the driving drum  33  in the axial direction. This causes the one end of the open-side cable  22   a  to be fixed to the driving drum  33 . 
     As well as this, one end of the close-side cable  22   b  introduced to the driving unit  21  is wound along the guide groove  33   a  from the other side of the driving drum  33  in the axial direction. Further, a locking block (not shown in the drawings) similar to that for the open-side cable  22   a  is also fixed to the one end of the close-side cable  22   b . This locking block (at the close side) is locked into a locking hole (not shown in the drawings), which is provided on the other side surface of the driving drum  33  in the axial direction. Thus, the one end of each of the open-side cable  22   a  and the close-side cable  22   b  is wound along the guide groove  33   a  of the driving drum  33 , and the other end thereof is connected to the sliding door  13 . 
     A board housing chamber (not shown in the drawings) is provided at a portion of a rear side of the drum housing chamber  30   a  in the case  30 . The portion is close to an open-side tensioner mechanism  40   a  and a close-side tensioner mechanism  40   b  (lower portion in  FIG. 3 ). A control board (not shown in the drawings) is accommodated in the board housing chamber. The control board is configured to control operations of the electric motor  31  and the electromagnetic clutch. The control board has a structure in which electronic components such as a CPU, a memory, and a driving circuit are mounted on a board. The control board is electrically connected to a battery (power source) mounted on the vehicle  10  and an opening/closing switch and the like in the vehicle interior (all of which are not shown in the drawings) via connector connecting units  35   a ,  35   b.    
     When the opening/closing switch receives an “opening operation” by a driver or the like, the electric motor  31  is rotatively driven in a counterclockwise direction. This causes the output shaft  32  and the driving drum  33  to rotate in the counterclockwise direction with high torque. Therefore, the open-side cable  22   a  is wound up around the driving drum  33  while pulling the sliding door  13 , whereby the sliding door  13  automatically carries out the open operation. At this time, with rotation of the driving drum  33  in the counterclockwise direction, the close-side cable  22   b  is sent out to the outside of the case  30  from the driving drum  33 . 
     On the other hand, when the opening/closing switch receives a “closing operation” by the driver or the like, the electric motor  31  is rotatively driven in a clockwise direction. This causes the output shaft  32  and the driving drum  33  to rotate in the clockwise direction with high torque. Therefore, the close-side cable  22   b  is wound up around the driving drum  33  while pulling the sliding door  13 , whereby the sliding door  13  automatically carries out the close operation. At this time, with rotation of the driving drum  33  in the clockwise direction, the open-side cable  22   a  is sent out to the outside of the case  30  from the driving drum  33 . 
     As shown in  FIG. 3 , an open-side tensioner housing chamber  30   b  and a close-side tensioner housing chamber  30   c  are provided in the case  30  so as to be adjacent to the drum housing chamber  30   a . Then, the open-side cable  22   a  and the close-side cable  22   b  introduced to the inside of the case  30  are respectively drawn to the open-side tensioner housing chamber  30   b  and the close-side tensioner housing chamber  30   c  from an open-side cable entrance portion  30   d  and a close-side cable entrance portion  30   e  provided on the case  30 . Namely, the cables  22   a ,  22   b  are respectively allowed to go in and out of the case  30  from the cable entrance portions  30   d ,  30   e , and are respectively introduced to the drum housing chamber  30   a  via the tensioner housing chambers  30   b ,  30   c.    
     The open-side tensioner mechanism  40   a  and the close-side tensioner mechanism  40   b  are respectively accommodated in the open-side tensioner housing chamber  30   b  and the close-side tensioner housing chamber  30   c . The open-side tensioner mechanism  40   a  and the close-side tensioner mechanism  40   b  respectively apply predetermined tension to the open-side cable  22   a  and the close-side cable  22   b . By providing the tensioner mechanisms  40   a ,  40   b  in this manner, each of the cables  22   a ,  22   b  does not bend even though any of the cables  22   a ,  22   b  is elongated due to repeated pulling operations for the sliding door  13  and a change in a path length thereof occurs. Illustration for each of the tensioner mechanisms  40   a ,  40   b  shown in  FIG. 3  is simplified in order to easily understand explanation thereof. 
     Here, outer tubes TU each having flexibility are respectively provided between the cable entrance portions  30   d ,  30   e  of the case  30  and the inversion pulleys  23   a ,  23   b . The cables  22   a ,  22   b  are respectively inserted into the outer tubes TU and are configured to move in the outer tubes TU between the cable entrance portions  30   d ,  30   e  and the inversion pulleys  23   a ,  23   b.    
     Further, an opening portion of the case  30  (near side in  FIG. 3 ) is blocked or closed by a cover made of resin (not shown in the drawings). This causes the drum housing chamber  30   a  and each of the tensioner housing chambers  30   b ,  30   c  to be sealed, whereby it is possible to surely prevent rain water, dust, or the like from entering the inside thereof. 
     Hereinafter, a detailed structure of the open-side tensioner mechanism  40   a  and the close-side tensioner mechanism  40   b  will be described by using the drawings. Note that each of the tensioner mechanisms  40   a ,  40   b  is formed into the same shape so as to become mirror-image symmetry across a central line P of  FIG. 3 . Therefore, a detailed structure thereof will be described below by representing the open-side tensioner mechanism  40   a . Further, in the following explanation, the open-side tensioner mechanism  40   a  will be described simply as a “tensioner mechanism  40 ”. 
       FIG. 6  shows a perspective view showing details of the open-side tensioner mechanism shown in  FIG. 3 .  FIG. 7  shows a perspective view when the tensioner mechanism shown in  FIG. 6  is viewed from a direction of an arrow A.  FIG. 8  shows a cross-sectional view taken along a B-B line of  FIG. 7 , which passes through a pulley shaft.  FIGS. 9( a ) and 9( b )  respectively show explanatory drawings for explaining a moving state of a pulley in an axial direction with respect to the pulley shaft of the pulley.  FIGS. 10( a ), 10( b ), and 10( c )  respectively show explanatory drawings for explaining a winding procedure of the cable to a pulley groove.  FIGS. 11( a ), 11( b ), and 11( c )  respectively show explanatory drawings for explaining that the cable is not dropped off from the pulley groove. 
     As shown in  FIG. 6  and  FIG. 7 , the tensioner mechanism  40  is provided between the driving drum  33  in the case  30  and the open-side cable entrance portion  30   d . The tensioner mechanism  40  includes a pulley holder  41  that is formed into a predetermined shape by means of injection molding of resin material such as plastics or the like. The pulley holder  41  includes a main body  42  and a guide shaft  43 . The main body  42  includes a pulley housing chamber  42   a  in the inside thereof. The guide shaft  43  is integrally provided with the main body  42 . 
     The main body  42  of the pulley holder  41  includes a pair of support walls  42   b  each of which is formed into a roughly rectangular shape. A first connecting wall  42   c  for connecting the support walls  42   b  to each other is provided at one side of each of the support walls  42   b  in a longitudinal direction. A second connecting wall  42   d  for connecting the support walls  42   b  is provided at the other side of each of the support walls  42   b  in the longitudinal direction. In other words, the first and second connecting walls  42   c  and  42   d  respectively support both sides of each of the support walls  42   b  in the longitudinal direction, and are disposed outside of the pulley  46  in a radial direction. Further, a base end side of the guide shaft  43  in an axial direction is coupled to an opposite side of the first connecting wall  42   c  with respect to the second connecting wall  42   d.    
     A tip side of the guide shaft  43  in the axial direction is fitted to a through hole (not shown in the drawings) provided on the open-side tensioner housing chamber  30   b  (see  FIG. 3 ) so as to be allowed to go in and out of the through hole. This allows the pulley holder  41  to move inside the case  30  in a direction (orthogonal direction) intersecting with an axial direction of the output shaft  32  (see  FIG. 3 ). Thus, the guide shaft  43  regulates a moving direction of the pulley holder  41  with respect to the case  30 . 
     Further, a coil spring (spring member)  44  is fitted to the guide shaft  43 . In other words, the guide shaft  43  also has a function as a spring supporting unit configured to support the coil spring  44 . The coil spring  44  is disposed between the open-side tensioner housing chamber  30   b  of the case  30  and the main body  42  of the pulley holder  41  in a state where a predetermined initial load is applied to the coil spring  44  (that is, a state where the coil spring  44  is contracted to an extent). Herewith, even though the open-side cable  22   a  extends and the path length increases, as shown by a two-dot chain line in  FIG. 3 , the pulley holder  41  is pressed to the coil spring  44 , thereby eliminating slack of the open-side cable  22   a . Thus, the coil spring  44  is configured to press the pulley holder  41  in a direction to increase a path length of the open-side cable  22   a  between the driving drum  33  and the open-side cable entrance portion  30   d.    
     As shown in  FIG. 8 , a pulley shaft  45  is provided between the pair of support walls  42   b  provided in the pulley holder  41  so as to cross the pulley housing chamber  42   a . The pulley shaft  45  is constituted by a columnar steel rod. Namely, the support walls  42   b  respectively support both sides of the pulley shaft  45  in an axial direction. The pulley shaft  45  is extended in a direction (orthogonal direction) intersecting with an extending direction of the guide shaft  43  (see  FIG. 7 ). Namely, the pulley shaft  45  becomes parallel to the output shaft  32  (see  FIG. 3 ). By caulking an end portion of the pulley shaft  45  in the axial direction, the pulley shaft  45  is fixed at a roughly central part of each of the support walls  42   b  (see  FIG. 6  and  FIG. 7 ). Since the both sides of each of the support walls  42   b  in the longitudinal direction are respectively supported by the connecting walls  42   c  and  42   d , each of the support walls  42   b  never bends at the time of caulking fixation of the pulley shaft  45  to the respective support walls  42   b.    
     The pulley  46  is rotatably supported on the pulley shaft  45 . Here, as shown in  FIG. 8 , a thickness dimension of the pulley  46  is set to a dimension of about a half of a thickness dimension of the pulley housing chamber  42   a . This allows the pulley  46  to move in the axial direction with respect to the pulley shaft  45  as shown by an arrow M 1 . Note that an adequate amount of grease (lubricating oil) is applied between the pulley  46  and the pulley shaft  45  at the time of assembling of the tensioner mechanism  40  (not shown in the drawings). This allows the pulley  46  to smoothly rotate and move with respect to the pulley shaft  45  over a long time. Here, the pulley  46  is movable in the axial direction of the pulley shaft  45 , but a moving amount thereof is controlled by the support walls  42   b.    
     The pulley  46  is formed into a roughly disk shape by resin material such as plastics. A cylindrical mounting portion  46   a  is provided inside the pulley  46  in the radial direction. The mounting portion  46   a  is mounted on the pulley shaft  45 . Grease stops  46   b  are respectively provided at both sides of the mounting portion  46   a  in an axial direction. Each of the grease stops  46   b  becomes depressed in the axial direction of the mounting portion  46   a . This causes grease to be supplied between the pulley  46  and the pulley shaft  45 . 
     An annular pulley body  46   c  is integrally provided outside the mounting portion  46   a  in the radial direction. A plurality of relief recesses  46   d  is formed between the mounting portion  46   a  and the pulley body  46   c . These relief recesses  46   d  are disposed at predetermined intervals in a circumferential direction of the pulley  46 , and contribute weight saving of the pulley  46  and prevention of deformation (or prevention of generation of a sink mark) at the time of injection molding of the pulley  46 . This makes it possible to sufficiently secure coaxiality between the mounting portion  46   a  and the pulley body  46   c , whereby the pulley  46  with high accuracy, which is made of resin, can be realized. 
     A pulley groove  50  is provided outside the pulley body  46   c  in the radial direction. A cross-sectional shape of the pulley groove  50  is formed into a circular arc shape. This pulley groove  50  is provided over the whole area of the pulley body  46   c  in a circumferential direction. As shown in  FIG. 8 , a radius dimension of a cross-sectional surface of the pulley groove  50  is R 1 . More specifically, a diameter dimension (R 1 ×2) of the cross-sectional surface of the pulley groove  50  becomes a dimension of about ⅔ (two third) of a thickness dimension of the pulley body  46   c.    
     Further, flange portions  51  are respectively provided at both sides (upper and lower sides in  FIG. 8 ) of the pulley body  46   c  in the axial direction. Each of the flange portions  51  projects outward in the radial direction from the pulley groove  50 . These flange portions  51  are provided over the whole area of the pulley body  46   c  in the circumferential direction. The flange portions  51  have a function to prevent the open-side cable  22   a  wound on the pulley groove  50  to drop off from the pulley groove  50 . 
     Moreover, connecting units  52  are respectively provided between the pulley groove  50  and the flange portions  51  along the axial direction of the pulley  46 . A cross-sectional shape of each of the connecting units  52  is formed into a circular arc shape. The pair of connecting units  52  is provided over the whole area of the pulley body  46   c  in the circumferential direction. A radius dimension of each of the connecting units  52  becomes a radius dimension R 2  that is roughly a half of the radius dimension R 1  of the pulley groove  50  (R 2 ≈R×½). Here, the pulley groove  50  becomes hollow toward the inside of the pulley body  46   c  in the radial direction, but the pair of connecting units  52  projects outward in the radial direction of the pulley body  46   c  and toward the pulley groove  50 . A curved line to form a cross-sectional surface of the pulley groove  50  is smoothly connected to a curved line to form a cross-sectional surface of each of the connecting units  52  each other at a connecting point CP ( FIG. 8  merely shows one point). No corner is formed at this connecting point CP. 
     Herewith, even though the open-side cable  22   a  flops in the pulley groove  50  by driving of the driving unit  21  (see  FIG. 3 ) and moves toward any of the flange portions  51 , the open-side cable  22   a  merely comes into contact with the pulley groove  50  with the radius dimension R 1  and the connecting unit  52  with the radius dimension R 2  (both are a potion having the circular arc shape). Therefore, since the open-side cable  22   a  does not come into contact with any corner unlike a conventional manner, it is possible to surely prevent early damage of the open-side cable  22   a.    
     Here, as shown in  FIG. 5 , the open-side cable  22   a  is formed by a wire WA and a film PF. The wire WA is formed by twisting a plurality of thin iron wires. The film PF is made of resin to coat an outer periphery of the wire WA. Further, a cross-sectional shape of the open-side cable  22   a  is a round shape, and a diameter dimension of the open-side cable  22   a  becomes φX. More specifically, the diameter dimension φX of the open-side cable  22   a  becomes a dimension of about ⅓ (one third) of the diameter dimension (R 1 ×2) of the cross-sectional surface of the pulley groove  50  (φX≈(R 1 ×2)/3). In other words, the radius dimension R 1  of the pulley groove  50  is set to a dimension that is equal to or larger than the diameter dimension φX of the open-side cable  22   a . Thus, according to the pulley  46 , it is possible to surely prevent early damage of the film PF having low rigidity. Therefore, it is possible to prevent the wire WA from being exposed to the outside to get rusty early or prevent a peeling film PF from obstructing the winding operation of the open-side cable  22   a  (that is, the operation of the driving unit  21 ). 
     As shown in  FIG. 8 , a projecting portion  60  is provided on the second connecting wall  42   d  that forms the main body  42  of the pulley holder  41 . The projecting portion  60  projects outside the pulley  46  in the radial direction thereof. A cross-sectional shape of the projecting portion  60  is formed in a U-shaped manner. A passing path  61  is formed inside the projecting portion  60 . The passing path  61  allows the locking block  34  (shown by a two-dot chain line in  FIG. 8 ) fixed to the one end of the open-side cable  22   a  to pass therethrough. A cross-sectional shape of the passing path  61  is formed into a roughly rectangular shape. The locking block  34  is not allowed to incline and rotate inside the passing path  61 . Therefore, the locking block  34  can pass through the passing path  61  smoothly, whereby it is possible to improve assembly operability of the driving unit  21  (see  FIG. 3 ). At the time of assembling of the driving unit  21 , an arranging operation of the open-side cable  22   a  to the pulley  46  is carried out as shown by a bold dashed arrow in  FIG. 6 . 
     As shown in  FIG. 6  and  FIG. 7 , the projecting portion  60  is provided in a range of about 90° around the pulley  46 , and is formed into a roughly circular arc shape in planar view. More specifically, the projecting portion  60  is disposed near the open-side cable entrance portion  30   d  (see  FIG. 3 ) with respect to a shaft center of the guide shaft  43 . 
     As shown in  FIG. 8 , a slit  62  is provided inside the projecting portion  60  in the radial direction. The slit  62  is configured to guide winding (or arrangement) of the open-side cable  22   a  from the passing path  61  to the pulley groove  50 . This slit  62  is provided over the whole area of the projecting portion  60  in a circumferential direction. A width dimension W 1  of an opening portion of the slit  62  becomes constant over the whole area of the projecting portion  60  in the circumferential direction. Here, the width dimension W 1  of the slit  62  is set to a width dimension by which the open-side cable  22   a  can pass therethrough, that is, a width dimension that is somewhat larger than the diameter dimension φX of the open-side cable  22   a  (W 1 &gt;φX). Herewith, the slit  62  allows the open-side cable  22   a  to pass therethrough, and controls the passage of the locking block  34 . Therefore, at the time of assembling of the driving unit  21 , winding of the open-side cable  22   a  onto the pulley groove  50  is guided without catching the locking block  34  by the slit  62 , whereby it is possible to carry out the work smoothly. 
     Further, a pair of taper portions  63  is formed between the passing path  61  and the slit  62 . The pair of taper portions  63  is configured to guide movement of the open-side cable  22   a  from the passing path  61  to the slit  62 . These taper portions  63  are provided over the whole area of the projecting portion  60  in a circumferential direction, and are disposed at both sides along the axial direction of the pulley shaft  45  on the passing path  61  and the slit  62 . This makes it possible to smoothly move the open-side cable  22   a  from the passing path  61  to the slit  62 , whereby it is possible to easily carry out a winding operation of the open-side cable  22   a  onto the pulley groove  50 . However, each of the taper portions  63  is not limited to a configuration in which the taper portion  63  is provided over the whole area of the projecting portion  60  in a circumferential direction. For example, a plurality of taper portions  63  may be provided partially in the circumferential direction of the projecting portion  60 . 
     As shown in  FIG. 8 , the projecting portion  60  is disposed at a central part of the second connecting wall  42   d  along the axial direction of the pulley shaft  45 . Herewith, in a state where the pulley  46  moves downward with respect to the pulley shaft  45  and the pulley  46  comes into contact with the lower support wall  42   b  (that is, a state shown in  FIG. 8 ), a peripheral portion of the flange portion  51  provided in the pulley  46  is caused to face the slit  62  from the radial direction of the pulley  46 . At this time, a clearance dimension W 2  between the slit  62  and the connecting unit  52  is a dimension larger than a clearance dimension W 3  between the slit  62  and the flange portion  51  (W 2 &gt;W 3 ). 
     Here, a size relationship of the diameter dimension φX of the open-side cable  22   a , the width dimension W 1  of the slit  62 , the clearance dimension W 2  between the slit  62  and the connecting unit  52 , and the clearance dimension W 3  between the slit  62  and the flange portion  51  is marshalled, it becomes “W 1 &gt;φX&gt;W 2 &gt;W 3 ”. Herewith, in a case where the winding operation of the open-side cable  22   a  onto the pulley groove  50  is carried out from the state shown in  FIG. 8 , the open-side cable  22   a  surely moves toward the pulley groove  50  without necessity of visual contact. This is because W 2  is larger than W 3  and the pulley  46  can move merely in a direction to make W 2  larger with respect to the pulley shaft  45  from the state shown in  FIG. 8 . In other words, as can be apparent from  FIG. 8 , W 2  can become larger due to movement of the pulley  46 , but W 3  does not become larger. Therefore, it is possible to carry out the winding operation of the open-side cable  22   a  onto the pulley groove  50  easily and surely. 
     Contrary to the above, in a state where the pulley  46  comes into contact with the upper support wall  42   b  (not shown in the drawings), the similar dimension relationship to the above can also be obtained. Therefore, in the state where the pulley  46  comes into contact with the upper support wall  42   b , it is also possible to carry out the winding operation of the open-side cable  22   a  onto the pulley groove  50  easily and surely. 
     As shown in  FIG. 9 , the guide groove  33   a  of the driving drum  33  is formed into a spiral shape. This causes a winding position of the open-side cable  22   a  with respect to the driving drum  33  (that is, a drawing position of the open-side cable  22   a  from the driving drum  33 ) to change to the axial direction of the driving drum  33  with rotation of the driving drum  33 . On the other hand, the cable entrance portion  30   d  of the case  30  is always in a position corresponding to a central part of the driving drum  33  in the axial direction regardless of the rotation of the driving drum  33 . Specifically, when a length of the driving drum  33  in the axial direction is E, the position of the cable entrance portion  30   d  becomes a position of E/2. 
     Herewith, an inclination angle Z of the open-side cable  22   a  between the cable entrance portion  30   d  and the driving drum  33  ( FIG. 9( a )  shows that the inclination angle Z becomes the maximum inclination angle of the open-side cable  22   a  based on a reference line C) changes on a reference point P 1  with the rotation of the driving drum  33 . When the inclination angle Z of the open-side cable  22   a  changes, a moving route of the open-side cable  22   a  at a position at which the pulley  46  is disposed changes in the axial direction of the pulley shaft  45  (that is, an up-and-down direction in  FIG. 9 ). Then, the pulley  46  moves in the axial direction with respect to the pulley shaft  45  so as to follow the change in the moving route of the open-side cable  22   a.    
     Here,  FIG. 9( a )  shows a state where the sliding door  13  (see  FIG. 2 ) is in a fully closed state and most of the open-side cable  22   a  is pulled out from the driving drum  33 . On the other hand,  FIG. 9( b )  shows a state where the sliding door  13  is in a fully opened state and most of the open-side cable  22   a  is wound up around the driving drum  33 . In other words, the open-side cable  22   a  swings on the reference line C in the up-and-down direction in  FIG. 9( a )  as shown by an arrow M 2  while opening and closing of the sliding door  13 . The maximum swing angle of the open-side cable  22   a  at this time is twice the inclination angle Z. 
     The open-side cable  22   a  carries out a swing motion in this manner while opening and closing the sliding door  13 . However, an extending direction of the pulley groove  50  maintains a state where it is kept parallel to the reference line C. For this reason, the open-side cable  22   a  carries out the swing motion on a reference point P 2  in the pulley groove  50 . At this time, the open-side cable  22   a  is strongly pressed toward the pair of flange portions  51  (see  FIG. 8 ), which is provided in the pulley  46 . On the other hand, in the present embodiment, the connecting unit  52  whose cross-sectional shape is the circular arc shape (see  FIG. 8 ) is provided between the pulley groove  50  and each of the flange portions  51 . For this reason, it is possible to disperse stress concentration that acts on the open-side cable  22   a  compared with the conventional manner. Therefore, it is possible to prevent the film PF (see  FIG. 5 ) of the open-side cable  22   a  from being early damaged. 
     Further, in order to eliminate slack thereof, relatively large pressing force (spring force of the coil spring  44 ) is transmitted to the open-side cable  22   a  from the coil spring  44  via the pulley  46 . Therefore, relatively large stress, which can generate so-called “irregular shape of winding (or losing shape)” so as to peel the film PF from the wire WA (see  FIG. 5 ), acts on the film PF of the open-side cable  22   a . On the other hand, in the present embodiment, the open-side cable  22   a  is brought into contact with the pulley groove  50  and the connecting unit  52  whose cross-sectional shapes are formed into the circular arc shape. For this reason, it is possible to disperse the stress concentration that acts on the open-side cable  22   a  compared with the conventional manner. In the conventional technique described above, a flat guide surface formed on an outer periphery of a pulley and corners of a pair of flange portions are pressed to a cable whose cross-sectional shape is a round shape. For this reason, there has been a possibility that “irregular shape of winding” due to stress concentration is early generated. 
     Here, with reference to  FIG. 9 , the radius dimension R 1  of the cross-sectional surface of the pulley groove  50  and the radius dimension R 2  of the connecting unit  52  (see  FIG. 8 ) are set in a manner as follows. This makes it possible to disperse the stress concentration to the open-side cable  22   a , and it is possible to effectively prevent the “irregular shape of winding” described above from being generated. 
     First, the diameter dimension (R 1 ×2) of the cross-sectional surface of the pulley groove  50  is set to a dimension larger than the diameter dimension φX of the open-side cable  22   a  ((R 1 ×2)&gt;φX). However, in a case where the diameter dimension (R 1 ×2) is set to a dimension excessively larger than the diameter dimension φX, dispersion of the stress concentration to the open-side cable  22   a  becomes insufficient as well as the conventional technique, whereby there is a possibility that the “irregular shape of winding” is early generated. 
     On the other hand, in a case where the diameter dimension (R 1 ×2) is set to a value close to the diameter dimension φX, an extending direction of the open-side cable  22   a  becomes parallel to the extending direction of the pulley groove  50 . In other words, in a state shown in  FIG. 9 , the open-side cable  22   a  cannot incline with respect to the pulley groove  50 . Then, the thickness dimension of the pulley  46  becomes thin, and the open-side cable  22   a  easily drops off from the pulley groove  50 . In addition, the pulley  46  is prized with respect to the pulley shaft  45 , whereby there is a possibility that they make smooth rotation and movement of the pulley  46  with respect to the pulley shaft  45  difficult. 
     Therefore, in the present embodiment, as a desirable numerical relationship between the diameter dimension (R 1 ×2) and the diameter dimension φX, the diameter dimension (R 1 ×2) is set to a dimension of about three times of the diameter dimension φX ((R 1 ×2)≈φX×3). 
     Further, the radius dimension R 2  of the connecting unit  52  and a winding length L of the open-side cable  22   a  with respect to the pulley groove  50  are set so that an inclination angle Y of a line segment AL linking the reference point P 2  and the connecting point CP with respect to the reference line C becomes larger than the maximum inclination angle Z of the open-side cable  22   a  on the reference line C (Y&gt;Z). This causes pressing force on the open-side cable  22   a  from the connecting unit  52  to be relieved. 
     Next, a winding procedure of the open-side cable  22   a  onto the pulley groove  50  will be described by using the drawings. 
     First, as shown by the dashed arrow in  FIG. 6 , the locking block  34  provided at the one end of the open-side cable  22   a  (see  FIG. 5 ) is inserted to the passing path  61  of the projecting portion  60  provided in the pulley holder  41 . This causes the open-side cable  22   a  to be led by the locking block  34  and inserted into the passing path  61 , and the open-side cable  22   a  is elastically deformed in accordance with a circular arc shape of the projecting portion  60 . Then, by pulling the open-side cable  22   a  toward the pulley  46  side, the open-side cable  22   a  is caused to pass through the slit  62 . At this time, the open-side cable  22   a  is smoothly guided to the slit  62  by the taper portions  63 . 
     Then, by further pulling the open-side cable  22   a  toward the pulley  46  side, the open-side cable  22   a  is introduced (or moved) to the pulley groove  50  via a space between the slit  62  and the connecting unit  52  as shown by an arrow ( 1 ) in  FIG. 10( a ) . As shown in  FIG. 8 , this is because the clearance dimension W 2  between the slit  62  and the connecting unit  52  is set to the dimension larger than the clearance dimension W 3  between the slit  62  and the flange portion  51 . Therefore, the open-side cable  22   a  never moves as a dashed arrow in  FIG. 10( a )  without necessity of visual contact with the open-side cable  22   a.    
     Subsequently, as shown by an arrow ( 2 ) in  FIG. 10( b ) , the open-side cable  22   a  introduced between the slit  62  and the connecting unit  52  causes the pulley  46  to be moved in the axial direction of the pulley shaft  45  (see  FIG. 8 ) as shown by an arrow ( 3 ). Herewith, as shown by an arrow ( 4 ) in  FIG. 10( c ) , the open-side cable  22   a  is wound (or arranged) in the pulley groove  50  as shown by an arrow ( 5 ), and the pulley  46  is moved in the axial direction of the pulley shaft  45 , whereby the pulley  46  returns to an original state shown in  FIG. 10( a ) . Thus, the winding operation of the open-side cable  22   a  onto the pulley groove  50  is completed. 
     Next, a situation that the open-side cable  22   a  does not drop off from the pulley groove  50  will be described by using the drawing. 
     When the open-side cable  22   a  is moved at high speed by the operation of the driving unit  21  (see  FIG. 3 ), for example, as shown by an arrow ( 6 ) in  FIG. 11( a ) , the open-side cable  22   a  may swell outward in the radial direction from the pulley groove  50  by means of centrifugal force against the open-side cable  22   a  or the like. Here, in a case where the pulley groove  50  faces the second connecting wall  42   d  from the radial direction, the open-side cable  22   a  can return to the pulley groove  50  immediately. On the other hand, in a case where the pulley groove  50  faces the slit  62  from the radial direction, as shown in  FIG. 11( a ) , the open-side cable  22   a  may reach the passing path  61 . 
     Even if the open-side cable  22   a  reaches the passing path  61 , as shown by an arrow ( 7 ) in  FIG. 11( b )  and an arrow ( 8 ) in  FIG. 11( c ) , the open-side cable  22   a  can return to the pulley groove  50  smoothly and quickly. This is because the clearance dimension W 2  between the slit  62  and the connecting unit  52  is set to the dimension larger than the clearance dimension W 3  between the slit  62  and the flange portion  51  (see  FIG. 8 ) as described above. Therefore, the open-side cable  22   a  that reaches the passing path  61  never moves as any of dashed arrows in  FIGS. 11( b ) and 11( c ) . 
     As described above in detail, according to the driving unit  21  of the first embodiment, the cross-sectional shape of the open-side cable  22   a  is formed into the round shape, and the cross-sectional shape of the connecting unit  52  between the pulley groove  50  of the pulley  46  and the flange portion  51  is formed into the circular arc shape. Thus, it is possible to surely suppress damage of the open-side cable  22   a  caused by being strongly pressed to the corner as the conventional manner. Therefore, it is possible to improve durability of the open-side cable  22   a , whereby it is possible to extend a maintenance cycle of the driving unit  21  and obtain high reliability. 
     Further, according to the driving unit  21  of the first embodiment, the cross-sectional shape of the pulley groove  50  is formed into the circular arc shape, and the radius dimension R 1  of the pulley groove  50  is set to the dimension that is equal to or larger than the diameter dimension φX of the open-side cable  22   a . Thus, the open-side cable  22   a  is allowed to carry out the swing motion around the reference point P 2  inside the pulley groove  50  (see  FIG. 9 ). This makes it possible to suppress the pulley  46  from being prized with respect to the pulley shaft  45  by means of the open-side cable  22   a , whereby it is possible to operate the pulley  46  smoothly. 
     Moreover, according to the driving unit  21  of the first embodiment, the projecting portion  60  is provided on the pulley holder  41 ; the passing path  61  through which the locking block  34  can pass into the projecting portion  60 ; and the slit  62  configured to guide the winding of the open-side cable  22   a  from the passing path  61  to the pulley groove  50  is further provided inside the projecting portion  60  in the radial direction. Therefore, it is possible to easily carry out the winding operation of the open-side cable  22   a  onto the pulley groove  50  at the time of assembling of the driving unit  21 . Therefore, it is possible to improve the assembly operability, and this makes it possible to enhance a yield ratio thereof. 
     Further, according to the driving unit  21  of the first embodiment, the width dimension W 1  of the slit  62  allows passage of the open-side cable  22   a , and is set to the dimension for controlling passage of the locking block  34 . Therefore, it is possible to further improve operability to assemble the driving unit  21 . Moreover, the taper portions  63  for guiding the movement of the open-side cable  22   a  from the passing path  61  to the slit  62  are formed between the passing path  61  and the slit  62 . Therefore, it is possible to further improve the assembly operability of the driving unit  21 . 
     Further, according to the driving unit  21  of the first embodiment, the projecting portion  60  is disposed at the central part of the second connecting wall  42   d  along the axial direction of the pulley shaft  45 , the clearance dimension W 2  between the slit  62  and the connecting unit  52  in the state where the pulley  46  comes into contact with one of the support walls  42   b  becomes the dimension larger than the clearance dimension W 3  between the slit  62  and the flange portion  51 . This makes it possible to carry out the winding operation of the open-side cable  22   a  onto the pulley groove  50  easily and surely at the time of assembling of the driving unit  21  (see  FIG. 10 ). Moreover, even if the open-side cable  22   a  reaches the passing path  61  during an operation of the driving unit  21 , it is possible to return the open-side cable  22   a  to the pulley groove  50  smoothly and quickly (see  FIG. 11 ). 
     Second Embodiment 
     Next, a second embodiment according to the present invention will be described in detail by using the drawing. Note that the same reference numerals are respectively applied to portions that have the similar functions to those of the first embodiment described above, and detail description thereof is omitted. 
       FIG. 12  is a cross-sectional view showing a pulley periphery of a tensioner mechanism according to the second embodiment. 
     In the second embodiment, as shown by an arrow M 3  of  FIG. 12 , only a point that a pulley  70  is provided swingably around a central point P 3  with respect to a pulley shaft  45  is different compared with the first embodiment (see  FIG. 8 ). Specifically, a cylindrical portion  71  formed into a cylindrical shape is provided inside the pulley  70  in a radial direction. A bearing member  72  made of resin material such as plastics is mounted inside this cylindrical portion  71  in the radial direction. 
     The inside of the bearing member  72  in the radial direction is fitted onto the pulley shaft  45  rotatably and movably in an axial direction. Further, an annular and circular convex surface  73  is formed outside the bearing member  72  in the radial direction. A predetermined curvature is set for the circular convex surface  73 . This circular convex surface  73  is slidably brought into contact with an annular and circular concave surface  74 . The circular concave surface  74  is formed inside the cylindrical portion  71  in the radial direction. Here, a predetermined gap S is formed between the cylindrical portion  71  and the pulley shaft  45 . This allows the pulley  70  to swing around the central point P 3  with respect to the pulley shaft  45 . 
     In the second embodiment formed as described above, the actions and effects similar to those according to the first embodiment described above can also be achieved. In addition to this, in the second embodiment, the pulley  70  is provided swingably with respect to the pulley shaft  45 . Thus, even in a case where such force that the pulley  70  is prized with respect to the pulley shaft  45  acts thereto from the open-side cable  22   a  (see  FIG. 8 ), the pulley  70  swings so as to follow this as shown by a two-dot chain line in  FIG. 12 . Therefore, it is possible to operate the pulley  70  more smoothly. 
     Third Embodiment 
     Next, a third embodiment according to the present invention will be described in detail by using the drawing. Note that the same reference numerals are respectively applied to portions that have the similar functions to those of the first embodiment described above, and detail description thereof is omitted. 
       FIG. 13  shows a cross-sectional view corresponding to  FIG. 8  that shows the tensioner mechanism according to the third embodiment. 
     In the third embodiment, only a cross-sectional shape of a pulley groove  80  is different compared with the first embodiment (see  FIG. 8 ). Specifically, the pulley groove  80  is provided over the whole area of the pulley body  46   c  in a circumferential direction so as to open toward the outside of the pulley  46  in a radial direction. A pair of flat surfaces  81 , which forms the pulley groove  80 , is respectively connected to a pair of connecting units  52 . 
     In the third embodiment formed as described above, the actions and effects similar to those according to the first embodiment described above can also be achieved. Here, since the open-side cable  22   a  is pressed to the pair of flat surfaces  81  (two places), it is possible to disperse stress concentration that acts on the open-side cable  22   a  to at least two places. Therefore, it is possible to suppress “irregular shape of winding” from being generated compared with a conventional manner in which the stress concentration acts on one place. 
     The present invention is not limited to each of the embodiments described above. It goes without saying that the present invention may be modified into various forms of applications without departing from the substance of the invention. For example, in each of the embodiments described above, the driving unit  21  is disposed inside the vehicle body  11 , and each of the cables  22   a ,  22   b  is connected to the sliding door  13 . However, the present invention is not limited to this structure. The present invention may have a structure in which the driving unit  21  is disposed inside the sliding door  13  and the cables  22   a ,  22   b  are fixed to both ends of the guide rail  14  via portions in the roller assembly  13   a  of the sliding door  13 . 
     Otherwise, quality of material, a shape, a dimension, the number, an installation location, and the like of each of the components of the wiper device according to each of the embodiments described above are arbitrary so long as each of them can achieve the present invention. Further, they are not limited to those in each of the embodiments described above. 
     An opening-closing body driving device is used to drive a sliding door that is mounted on a side portion of a vehicle body in a vehicle and opens and closes an opening portion formed at the side portion of the vehicle body.