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CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application represents the national stage entry of PCT International Application No. PCT/IB2013/052664 filed Apr. 3, 2013 which claims the benefit of Japanese Patent Application 2012-084967 filed Apr. 3, 2012, both of which are hereby incorporated herein by reference for all purposes. 
     TECHNICAL FIELD 
     The present disclosure is in a technical field of a drive device configured to drive two driven members, such as a sunroof and a shade, provided at an opening formed in a fixed roof of a vehicle. 
     BACKGROUND ART 
     A drive device including a single motor, a drive gear connected to an output shaft of the motor, first and second transmission gears engaged with the drive gear, first and second output shafts connected respectively to the first and second transmission gears, and first and second pinion gears rotatably connected respectively to the first and second output shafts has been known as the drive device of this type (see, e.g., Patent Document 1). A first geared cable configured to drive a first driven member is engaged with the first pinion gear, and a second geared cable configured to drive a second driven member is engaged with the second pinion gear. According to the foregoing configuration, two driven members (i.e., the first and second driven members) can be simultaneously driven by a single motor. 
     CITATION LIST 
     Patent Document 
     [Patent Document 1] Japanese Utility Model Publication No. S62-196885 
     SUMMARY OF THE INVENTION 
     Technical Problem 
     For example, a glass panel and a shade may be employed as the foregoing two driven members. In such a case, user needs such as a need for opening only the shade while maintaining the glass panel closed or a need for closing only the glass panel while maintaining the shade open vary depending on, e.g., weather outside a vehicle and the intensity of sunlight. 
     However, in the conventional drive device as described in Patent Document 1, the single motor is driven to simultaneously drive the two driven members, and therefore the opening/closing operation for, e.g., closing only the glass panel or opening only the shade as described above cannot be realized. Thus, the user needs cannot be satisfied. In order to satisfy the user needs, it is necessary to prepare two drive motors, resulting in disadvantages that the size of the entirety of the device and a device cost are increased. 
     In order to overcome the foregoing disadvantages, an electromagnetic clutch may be provided between the output shaft and the pinion gear to switch connection/disconnection of the output shaft and the pinion gear. In such a manner that connection/disconnection in each electromagnetic clutch is switched depending on the user needs, the drive device can be switched between the state in which rotative power of the motor is transmitted to both of the two pinion gears (i.e., the two driven members) and the state in which rotative power of the motor is selectively transmitted to one of the pinion gears. 
     In the foregoing case, although the user needs can be satisfied, the following disadvantage is caused: when, e.g., one of the electromagnetic clutches is in a disconnection state, if vehicle collision occurs, the pinion gear disconnected from the output shaft by the electromagnetic clutch easily moves (i.e., rotates) due to impact upon the collision. This results in the following disadvantages: the position of the opened/closed driven member connected to the pinion gear cannot be accurately determined by an ECU; and such a driven member is slammed shut by rotation of the pinion gear and therefore is damaged. 
     The present disclosure has been made in view of the foregoing, and it is an objective of the present disclosure to devise a configuration of a drive device configured to drive two driven members, such as a sunroof and a shade, provided at an opening formed in a fixed roof of a vehicle such that the drive device is, depending on user needs, switchable between an unselective transmission state in which power of a motor is transmitted to both of the driven members and a selective transmission state in which power of the motor is selectively transmitted to one of the driven members and that, if vehicle collision occurs in the selective transmission state, the other driven member for which power transmission from the motor is blocked is prevented from easily moving due to impact upon the collision. 
     Solution to the Problem 
     A first aspect of the invention is intended for a drive device for driving first and second driven members provided at an opening formed in a fixed roof of a vehicle. 
     The drive device includes a single motor; a single drive gear directly connected to an output shaft of the motor or connected to the output shaft of the motor through a reduction gear; first and second power transmission gears engaged with the drive gear; a first output shaft connected to the first power transmission gear so as to rotate together with the first power transmission gear; a second output shaft connected to the second power transmission gear so as to rotate together with the second power transmission gear; a first pinion gear engaged with a first drive cable for driving the first driven member and supported so as to be fitted onto the first output shaft; a second pinion gear engaged with a second drive cable for driving the second driven member and supported so as to be fitted onto the second output shaft; a first electromagnetic clutch configured to switch between a connection state in which the first pinion gear is connected to the first output shaft so as to rotate together with the first output shaft and a disconnection state in which the first pinion gear and the first output shaft are disconnected from each other; and a second electromagnetic clutch configured to switch between a connection state in which the second pinion gear is connected to the second output shaft so as to rotate together with the second output shaft and a disconnection state in which the second pinion gear and the second output shaft are disconnected from each other. The first electromagnetic clutch includes first fixing means configured to unrotatably fix the first pinion gear to a fixed member of the vehicle in the disconnection state of the first electromagnetic clutch, and the second electromagnetic clutch includes second fixing means configured to unrotatably fix the second pinion gear to the fixed member of the vehicle in the disconnection state of the second electromagnetic clutch. 
     According to the first aspect of the invention, when the motor is driven, rotative power of the motor is transmitted from the drive gear to the first and second output shafts through the first and second power transmission gears. The rotative power transmitted to the first and second output shafts is transmitted to the first and second pinion gears. In the present disclosure, the first electromagnetic clutch is interposed between the first output shaft and the first pinion gear, and the second electromagnetic clutch is interposed between the second output shaft and the second pinion gear. Thus, rotative power of the motor can be, depending on user needs, transmitted to both of the pinion gears or be selectively transmitted to one of the pinion gears. 
     That is, when both of the first and second electromagnetic clutches are in the connection state, rotative power of the motor is transmitted to the first and second pinion gears through the first and second output shafts. As a result, the first and second driven members are simultaneously driven by the first and second drive cables engaged respectively with the first and second pinion gears. 
     On the other hand, when only the first electromagnetic clutch is in the connection state and the second electromagnetic clutch is in the disconnection state, rotative power of the motor is transmitted only to the first pinion gear through the first output shaft, and is not transmitted to the second pinion gear. As a result, while the second driven member is stopped, only the first driven member is driven by the first drive cable engaged with the first pinion gear. Upon driving, power transmission between the second pinion gear and the motor is blocked. However, since the second pinion gear is fixed to the fixed roof by the second fixing means of the second electromagnetic clutch, the second pinion gear does not move due to, e.g., impact even if vehicle collision occurs. 
     Moreover, when only the second electromagnetic clutch is in the connection state and the first electromagnetic clutch is in the disconnection state, rotative power of the motor is transmitted only to the second pinion gear through the second output shaft, and is not transmitted to the first pinion gear. As a result, while the first driven member is stopped, only the second driven member is driven by the second drive cable engaged with the second pinion gear. Upon driving, power transmission between the first pinion gear and the motor is blocked. However, since the first pinion gear is fixed to the fixed roof by the first fixing means of the first electromagnetic clutch, the first pinion gear does not move due to, e.g., impact even if vehicle collision occurs. 
     Thus, in the present disclosure, in such a manner that connection/disconnection in each of the electromagnetic clutches is switched, the drive device is, depending on the user needs, switchable between an unselective transmission state in which power of the motor is transmitted to both of the first and second driven members and a selective transmission state in which power of the motor is selectively transmitted to one of the driven members. Moreover, if vehicle collision occurs in the selective transmission state, the other driven member for which power transmission from the motor is blocked is prevented from easily moving due to impact upon the collision. 
     A second aspect of the invention is intended for the drive device of the first aspect of the invention, in which the first electromagnetic clutch further includes a fixed clutch plate coaxially fixed to the first output shaft so as to rotate together with the first output shaft, and a movable clutch plate supported so as to slide in an axial direction on the first pinion gear and to rotate together with the first pinion gear and arranged so as to face the fixed clutch plate in the axial direction, and a clutch engagement part to be engaged with an engagement part of the fixed clutch plate when the first electromagnetic clutch is in the connection state is formed at one of side surfaces of the movable clutch plate, a fixing engagement part to be engaged with an engagement part of the fixed member of the vehicle when the first electromagnetic clutch is in the disconnection state is formed at the other side surface of the movable clutch plate, and the fixing engagement part serves as the first fixing means. 
     A third aspect of the invention is intended for the drive device of the second aspect of the invention, in which the second electromagnetic clutch further includes a fixed clutch plate coaxially fixed to the second output shaft so as to rotate together with the second output shaft, and a movable clutch plate supported so as to slide in the axial direction on the second pinion gear and to rotate together with the second pinion gear and arranged so as to face the fixed clutch plate in the axial direction, and a clutch engagement part to be engaged with an engagement part of the fixed clutch plate when the second electromagnetic clutch is in the connection state is formed at one of side surfaces of the movable clutch plate, a fixing engagement part to be engaged with an engagement part of the fixed member of the vehicle when the second electromagnetic clutch is in the disconnection state is formed in the other side surface of the movable clutch plate, and the fixing engagement part serves as the second fixing means. 
     According to the second and third aspects of the invention, if one of the first and second electromagnetic clutches is in the disconnection state, the fixing engagement part of the movable clutch plate of the electromagnetic clutch which is in the disconnection state is engaged with the engagement part provided in the fixed member of the vehicle. As a result, the pinion gear connected to the movable clutch plate so as to rotate together with the movable clutch plate is unrotatably fixed to the fixed member. Thus, even if vehicle collision occurs in such a state, the pinion gear does not move. 
     The clutch engagement part is formed at one of the side surfaces of the single movable clutch plate, and the fixing engagement part is formed at the other side surface. Thus, it can be ensured that the pinion gear disconnected from the output shaft is fixed with a simple configuration. 
     Advantages of the Invention 
     As described above, according to the drive device of the present disclosure, the drive device is, depending on the user needs, switchable between the unselective transmission state in which power of the motor is transmitted to both of the two driven members and the selective transmission state in which power of the motor is transmitted to one of the two driven members. Moreover, it can be ensured that, if vehicle collision occurs in the selective transmission state, the other driven member for which power transmission from the motor is blocked is prevented from moving due to impact upon the collision. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view diagonally from a front upper left side of a vehicle, and illustrates a fixed roof of the vehicle on which a drive unit (drive device) of an embodiment is mounted. 
         FIG. 2  is a perspective view from a side close to a pinion gear, and illustrates the drive unit. 
         FIG. 3  is a perspective view illustrating an internal structure of the drive unit, and illustrates the case where a first electromagnetic clutch is in a connection state and a second electromagnetic clutch is in a disconnection state. 
         FIG. 4  is a perspective view from a side opposite to the side close to the pinion gear, and illustrates the drive unit. 
         FIGS. 5( a ) and 5( b )  are cross-sectional views along a V-V line illustrated in  FIG. 3 .  FIG. 5( a )  illustrates the case where the electromagnetic clutch is in the disconnection state.  FIG. 5( b )  illustrates the case where the electromagnetic clutch is in the connection state. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     An embodiment of the present disclosure will be described below in detail with reference to drawings. 
       FIG. 1  is a perspective view of a sunroof apparatus  100 . In the present specification, a front side and a rear side in a front-back direction of a vehicle are, for the sake of simplicity of description, referred to as “front” and “rear,” and a left side and a right side in a vehicle width direction are referred to as “left” and “right.” 
     The sunroof apparatus  100  is mounted at an opening  2  formed in a fixed roof  1  of the vehicle. The sunroof apparatus  100  includes a frame  3  arranged along an edge of the opening  2 , a fixed panel (glass panel in the present embodiment)  4  attached so as to be fixed at the rear half of the frame  3 , a movable panel  5  movably attached to the frame  3 , an opening/closing mechanism (not shown in the figure) configured to open/close the movable panel  5 , and a roller shade  6  attached to a lower side of the fixed panel  4 . 
     The opening/closing mechanism is, e.g., a well-known mechanism described in Japanese Patent Publication No. 2000-185554, and includes a pair of right and left sliders (not shown in the figure) connected, by cams, to an elongated panel support plate fixed to a lower surface of the movable panel  5 . Each of the sliders is connected to a corresponding one of right and left guide rails  7  which form right and left parts of the frame  3 , and is slidable in the front-back direction. In such a manner that the sliders move so as to slide in the front-back direction, the movable panel  5  is inclined together with the panel support plate or moves so as to slide back and forth. The sliders are driven by a later-described drive unit  10  through a first geared cable  8 . 
     The roller shade  6  includes a winding roller  15  extending in the vehicle width direction, and a shade (light shielding sheet)  16  wound around the winding roller  15 . A garnish  17  extending in the vehicle width direction is connected to an end part of the shade  16  on a side on which the shade  16  is pulled out, and a runner part is formed in each of end parts of the garnish  17  in the vehicle width direction. Each of the runner parts is connected to a corresponding one of the guide rails  7  so as to slide in the front-back direction. In such a manner that the runner parts move back and forth along the guide rails  7 , the shade  16  is opened/closed. The runner parts are driven by the drive unit  10  through a second geared cable  9 . 
     Each of the first and second geared cables  8 ,  9  is formed of a cable member including a gear part at an outer circumferential surface thereof, and is accommodated in a groove formed in the frame  3  so as to move in a length direction. 
     The drive unit  10  is attached to a lower surface of a front end part of the frame  3  (i.e., to a side surface of a vehicle interior). Specifically, the drive unit  10  is, referring to  FIGS. 2-5 , a unit configured such that a single electrical motor (hereinafter simply referred to as a “motor”)  18 , a single drive gear  19 , and first and second gear mechanisms  20 ,  40  connected to the drive gear  19  are supported on a single casing  50 . The first gear mechanism  20  is a mechanism configured to transmit rotative power of the drive gear  19  to the first geared cable  8  which is a cable for driving the movable panel  5  (i.e., the sliders), and the second gear mechanism  40  is a mechanism configured to transmit rotative power of the drive gear  19  to the second geared cable  9  which is a cable for driving the shade  16  (i.e., the runner parts). In the present embodiment, the movable panel  5  corresponds to a first driven member, and the shade  16  corresponds to a second driven member. 
     The motor  18  is electrically connected to an ECU which is not shown in the figure, and is operated by receiving a command from the ECU. In the present embodiment, the motor  18  is arranged such that an output shaft thereof faces in the vehicle width direction. A worm gear  51  is connected to the output shaft of the motor  18  so as to rotate together with the output shaft of the motor  18 , and an input gear  53  configured to rotate about an axis perpendicular to the output shaft  52  of the motor  18  is engaged with the worm gear  51 . The input gear  53  is a helical gear. The input gear  53  is, through an input shaft  54  (illustrated only in  FIG. 3 ) extending in the vertical direction, connected to the drive gear  19  so as to rotate together with the drive gear  19 . 
     Referring to  FIGS. 3 and 5 , the first gear mechanism  20  includes a first power transmission gear  21  engaged with the drive gear  19 , a first output shaft  22  connected to the first power transmission gear  21  so as to rotate together with the first power transmission gear  21 , a first pinion gear  23  rotatably connected to the first output shaft  22 , and a first electromagnetic clutch  24 . The drive gear  19  and the first power transmission gear  21  are both spur gears. The first pinion gear  23  is a helical gear, and is engaged with the first geared cable  8  connected to the sliders. 
     The first electromagnetic clutch  24  is an engagement clutch configured to engage/disengage a fixed clutch plate  25  and a movable clutch plate  26  with/from each other to switch transmission of rotative power of the motor to the first pinion gear  23  between 
     ON and OFF. Specifically, the first electromagnetic clutch  24  is configured to switch between a connection state in which the first pinion gear  23  is connected to the first output shaft  22  so as to rotate together with the first output shaft  22  and a disconnection state in which the first pinion gear  23  and the first output shaft  22  are disconnected from each other. The operation of the first electromagnetic clutch  24  will be described in detail later. 
     The first output shaft  22  extends in the vertical direction so as to be parallel to the input shaft  54 . The first power transmission gear  21  is connected and fixed to a lower end part of the first output shaft  22 , and the first pinion gear  23  is supported so as to be fitted onto an upper end part of the first output shaft  22  with an upper bearing  27  being interposed therebetween. 
     The first output shaft  22  is a stepped shaft having a large-diameter shaft part  22   a  and a small-diameter shaft part  22   b  upwardly extending from an upper end part of the large-diameter shaft part  22   a . An annular clutch casing  35  having the closed bottom is fitted onto the large-diameter shaft part  22   a  with a lower bearing  28  being interposed therebetween. An annular electromagnetic coil  36  is coaxially accommodated in the clutch casing  35 , and an insulating block  37  is interposed between an inner circumferential surface of the electromagnetic coil  36  and an inner circumferential wall of the clutch casing  35 . The electromagnetic coil  36  is configured such that the ECU which is not shown in the figure switches current application to the electromagnetic coil  36  between ON and OFF. An opening of the clutch casing  35  at an upper end thereof is closed by the fixed clutch plate  25 . Although not shown in the figure, a slight clearance is formed between a lower surface of a circumferential edge part of the fixed clutch plate  25  and an upper end surface of the clutch casing  35 . Thus, the fixed clutch plate  25  and the clutch casing  35  do not contact each other. The lower bearing  28  is a substantially cylindrical plain bearing, and upper and lower end parts of the lower bearing  28  form upper and lower flange parts  28   a ,  28   b  outwardly protruding in a radial direction, respectively. The clutch casing  35  is, at an inner circumferential edge part of a lower surface thereof, supported in the state in which the inner circumferential edge part contacts an upper surface of the lower flange part  28   b  of the lower bearing  28 . The fixed clutch plate  25  slidably contacts an upper surface of the upper flange part  28   a  of the lower bearing  28 . 
     The fixed clutch plate  25  is formed of a discoid metal member. In a circumferential edge part of an upper surface of the fixed clutch plate  25 , a plurality of engagement recessed parts  25   a  are formed at predetermined intervals in a circumferential direction. An annular clearance groove  25   b  allowing deformation of a plate spring  30  upon operation (connection) of the clutch is formed in part of the upper surface of the fixed clutch plate  25  on an inner side relative to the engagement recessed parts  25   a  in the radial direction. An engagement hole  25   c  into which a base part of the small-diameter shaft part  22   b  of the first output shaft  22  is fitted is formed in a center part of the fixed clutch plate  25 . In the base part of the small-diameter shaft part  22   b , two flat cut surfaces  22   f  are formed so as to have a width across flats. In such a manner that the base part of the small-diameter shaft part  22   b  is fitted into the engagement hole  25   c  of the fixed clutch plate  25 , rotation of the fixed clutch plate  25  relative to the first output shaft  22  is restricted. Thus, the fixed clutch plate  25  is connected to the first output shaft  22  so as to rotate together with the first output shaft  22 . 
     In part of the first gear mechanism  20  above the cut surfaces  22   f  of the small-diameter shaft part  22   b , the first pinion gear  23  and the movable clutch plate  26  are supported. The first pinion gear  23  is supported so as to be fitted onto the small-diameter shaft part  22   b  with the upper bearing  27  being interposed therebetween. The first pinion gear  23  includes a gear body  23   a  including a tooth part at an outer circumferential surface thereof, a flange part  23   b  outwardly protruding from a lower end part of the gear body  23   a  in the radial direction, and a cylindrical part  23   c  downwardly protruding from an inner circumferential edge part of the flange part  23   b . An outer circumferential surface of the cylindrical part  23   c  is slidable on an inner circumferential surface of the movable clutch plate  26 . The outer circumferential surface of the cylindrical part  23   c  also serves as a guide surface on which the movable clutch plate  26  is slidably guided in the vertical direction. 
     A block-shaped key part  23   f  (see  FIGS. 3 and 5 ( b )) outwardly extending from the outer circumferential surface of the cylindrical part  23   c  in the radial direction and having a rectangular cross section is formed at a lower surface of the flange part  23   b  of the first pinion gear  23 . 
     The movable clutch plate  26  is formed in a substantially discoid shape, and is arranged so as to face the fixed clutch plate  25  in an axial direction. A key groove  26   f  (illustrated only in  FIG. 3 ) extending in the radial direction is formed at an upper surface of the movable clutch plate  26 . In such a manner that the key part  23   f  of the first pinion gear  23  is fitted into the key groove  26   f , the movable clutch plate  26  is connected to the first pinion gear  23  so as to rotate together with the first pinion gear  23 . Even when the movable clutch plate  26  downwardly slides to be engaged with the fixed clutch plate  25 , the key part  23   f  of the first pinion gear  23  has an enough height so as not to be detached from the key groove  26   f.    
     A plurality of raised clutch tooth parts  26   a  are formed at a lower surface of an outer circumferential edge part of the movable clutch plate  26 , and a plurality of engagement recessed parts  26   b  for fixing are formed at an upper surface of the outer circumferential edge part of the movable clutch plate  26 . The clutch tooth parts  26   a  are arranged apart from each other in the circumferential direction, and the engagement recessed parts  26   b  are arranged apart from each other in the circumferential direction. A deformation recessed part  26   g  allowing deformation of the plate spring  30  upon operation of the first electromagnetic clutch  24  (i.e., upon current application) is formed at a lower surface of an inner circumferential edge part of the movable clutch plate  26 . 
     In the state in which current application to the electromagnetic coil  36  is OFF, the movable clutch plate  26  is upwardly biased by the plate spring  30 . The plate spring  30  includes a ring part  30   a  sandwiched between an upper surface of a flange part  27   a  of the upper bearing  27  and a lower end surface of the first pinion gear  23 , and three elastic arm parts  30   b  (only two elastic arm parts  30   b  are illustrated in  FIG. 5 ) radially extending from the ring part  30   a  toward the outside in the radial direction. Each of the elastic arm parts  30   b  is configured to be vertically flexible about a point of support, i.e., a base end part thereof. In the state in which current application to the electromagnetic coil  36  is OFF, the movable clutch plate  26  is upwardly biased such that an engagement raised part  3   a  formed in the frame  3  is fitted into a corresponding one of the engagement recessed parts  26   b  formed at the upper surface of the movable clutch plate  26 . Thus, the movable clutch plate  26  is fixed so as not to rotate relative to the frame  3 , and therefore the first pinion gear  23  connected to the movable clutch plate  26  is fixed so as not to rotate relative to the frame  3 . The plurality of engagement raised parts  3   a  are formed at a lower surface of a front side part of the frame  3 , and are formed at positions corresponding to the engagement recessed parts  26   b  formed at the upper surface of the movable clutch plate  26 . The engagement raised parts  3   a  are not necessarily formed in the frame  3 . For example, the engagement raised parts  3   a  may be formed in the fixed roof  1  or a frame member of the vehicle. 
     A C-washer  32  is fitted into an upper end part of the small-diameter shaft part  22   b  of the first output shaft  22 , thereby preventing detachment of the first pinion gear  23  toward the above. A ring washer  33  and a wave washer  34  are interposed between the C-washer  32  and the first pinion gear  23 . 
     The operation of the first gear mechanism  20  of the drive unit  10  configured as described above will be described in detail with reference to  FIGS. 5( a ) and 5( b ) . 
     First, in the state in which current application to the electromagnetic coil  36  by the ECU is OFF, the engagement raised parts  3   a  of the frame  3  are, as described above, fitted into the engagement recessed parts  26   b  formed at the upper surface of the movable clutch plate  26 , and the movable clutch plate  26  and the fixed clutch plate  25  are not engaged with each other (see  FIG. 5( a ) ). Thus, in such a state, rotative power of the first output shaft  22  is not transmitted to the first pinion gear  23  by way of the fixed clutch plate  25  and the movable clutch plate  26 . Thus, in the foregoing state, the first electromagnetic clutch  24  is in the disconnection state in which the first pinion gear  23  and the first output shaft  22  are disconnected from each other. 
     When current application to the electromagnetic coil  36  by the ECU is ON, the movable clutch plate  26  receives magnetic attractive force from the electromagnetic coil  36 , and downwardly moves against biasing force of the plate spring  30  (see  FIG. 5( b ) ). As a result, the engagement raised parts  3   a  of the frame  3  are disengaged from the engagement recessed parts  26   b  formed at the upper surface of the movable clutch plate  26 , and the clutch tooth parts  26   a  formed at the lower surface of the movable clutch plate  26  are fitted into the engagement recessed parts  25   a  of the fixed clutch plate  25 . Consequently, rotative power of the first output shaft  22  is transmitted to the first pinion gear  23  through the fixed clutch plate  25  and the movable clutch plate  26 , thereby rotating the first pinion gear  23 . In the foregoing manner, the first electromagnetic clutch  24  switches to the connection state in which the first pinion gear  23  is connected to the first output shaft  22 . 
     When the first electromagnetic clutch  24  switches from the disconnection state to the connection state, rotation of the first output shaft  22  is transmitted to the first pinion gear  23 . As a result, the sliders are driven in the front-back direction by the first geared cable  8  engaged with the first pinion gear  23 , and therefore the movable panel  5  is opened/closed by the panel support plate connected to the sliders by the cams. 
     Next, the second gear mechanism  40  will be described. The second gear mechanism includes a second power transmission gear  41  engaged with the drive gear  19 , a second output shaft  42  connected to the second power transmission gear  41  so as to rotate together with the second power transmission gear  41 , a second pinion gear  43  rotatably connected to the second output shaft  42 , and a second electromagnetic clutch  44 . 
     The second geared cable  9  connected to the runner parts of the roller shade  6  are engaged with the second pinion gear  43 . When the second pinion gear  43  rotates, the runner parts (not shown in the figure) of the roller shade  6  are driven in the front-back direction by the second geared cable  9 , and therefore the shade  16  moves in an opening/closing direction (i.e., the front-back direction) together with the runner parts. 
     The detailed configuration of the second gear mechanism  40  is the same as that of the first gear mechanism  20 . Thus, the detailed description will not be repeated, supposing that the “first output shaft  22 ” corresponds to the “second output shaft  42 ,” the “first pinion gear  23 ” corresponds to the “second pinion gear  43 ,” the “first electromagnetic clutch  24 ” corresponds to the “second electromagnetic clutch  44 ,” and the “fixed clutch plate  25 ,” the “engagement recessed parts  25   a,”  the “movable clutch plate  26 ,” the “clutch tooth parts  26   a,”  and the “engagement recessed parts  26   b”  together forming the first electromagnetic clutch  24  corresponds a “fixed clutch plate  45 ,” “engagement recessed parts  45   a,”  a “movable clutch plate  46 ,” “clutch tooth parts  46   a,”  and “engagement recessed parts  46   b”  (see  FIGS. 5( a ) and 5( b ) ), respectively.  FIGS. 5( a ) and 5( b )  illustrate the case where the first electromagnetic clutch  24  is in the connection state and the second electromagnetic clutch  44  is in the disconnection state. 
     In the drive unit  10  configured as described above, when both of the first and second electromagnetic clutches  24 ,  44  are in the connection state, rotative power of the motor  18  is transmitted to the first and second pinion gears  23 ,  43  through the first and second output shafts  22 ,  42 . As a result, both of the movable panel  5  and the shade  16  are simultaneously driven by the first and second geared cables  8 ,  9  engaged respectively with the first and second pinion gears  23 ,  43 . 
     On the other hand, when only the first electromagnetic clutch  24  is in the connection state and the second electromagnetic clutch  44  is in the disconnection state, rotative power of the motor  18  is transmitted only to the first pinion gear  23  through the first output shaft  22 , and is not transmitted to the second pinion gear  43 . As a result, while the shade  16  is stopped, only the movable panel  5  is driven by the first geared cable  8  engaged with the first pinion gear  23 . 
     Moreover, when only the second electromagnetic clutch  44  is in the connection state and the first electromagnetic clutch  24  is in the disconnection state, rotative power of the motor  18  is transmitted only to the second pinion gear  43  through the second output shaft  42 , and is not transmitted to the first pinion gear  23 . As a result, while the movable panel  5  is stopped, only the shade  16  is driven by the second geared cable  9  engaged with the second pinion gear  43 . 
     In the present embodiment, in such a manner that connection/disconnection in each of the first and second electromagnetic clutches  24 ,  44  is switched depending on user needs, the drive device can switch between an unselective transmission state in which rotative power of the motor  18  is transmitted to both of the movable panel  5  and the shade  16  and a selective transmission state in which rotative power of the motor  18  is selectively transmitted to one of the movable panel  5  or the shade  16 . 
     Since each of the first and second pinion gears  23 ,  43  is connected to the output shaft  52  of the motor  18  through a corresponding one of the first and second output shafts  22 ,  42  in the unselective transmission state, braking force of the motor  18  constantly acts on each of the pinion gears  23 ,  43 . Such braking force is substantially-great rotational resistance force generated by the motor  18  functioning as a type of a generator when the motor  18  is forcibly rotated. Thus, when vehicle collision occurs in the unselective transmission state, even if a rotational load acts on each of the pinion gears  23 ,  43  due to impact upon the collision, each of the pinion gears  23 ,  43  is not easily moved (rotated). 
     On the other hand, since one of the electromagnetic clutches  24 ,  44  is in the disconnection state in the selective transmission state, braking force of the motor  18  does not act on the pinion gear  23  (or  43 ) disconnected from the output shaft  22  (or  42 ). Thus, when vehicle collision occurs in the selective transmission state, there is a possibility that the pinion gear  23  (or  43 ) unexpectedly rotates due to impact upon the collision. However, in the present embodiment, the pinion gear  23  (or  43 ) is fixed to the frame  3  which is a fixed member of the vehicle through the movable clutch plate  26  (or  46 ). Thus, it can be ensured that unexpected rotation of the pinion gear  23  (or  43 ) is prevented. 
     That is, when only the first electromagnetic clutch  24  is in the connection state and the second electromagnetic clutch  44  is in the disconnection state, the second pinion gear  43  and the second output shaft  42  are disconnected from each other. However, the engagement raised parts  3   a  of the frame  3  are fitted into the engagement recessed parts  46   b  (see  FIG. 3 ) formed at the upper surface of the movable clutch plate  46  connected to the second pinion gear  43 . Thus, the second pinion gear  43  and the movable clutch plate  46  are fixed to the frame  3  so as to rotate together with the frame  3 . As a result, when vehicle collision occurs, the second pinion gear  43  does not rotate due to impact upon the collision. Consequently, inaccurate determination of the position of the opened/closed shade  16  (i.e., the rotation angle of the second pinion gear  43 ) by the ECU can be prevented. 
     Moreover, when only the second electromagnetic clutch  44  is in the connection state and the first electromagnetic clutch  24  is in the disconnection state, the first pinion gear  23  and the first output shaft  22  are disconnected from each other. However, the engagement raised parts  3   a  of the frame  3  are fitted into the engagement recessed parts  26   b  (see  FIGS. 3, 5 ( a ), and  5 ( b )) formed at the upper surface of the first pinion gear  23 . Thus, the first pinion gear  23  and the movable clutch plate  26  are configured to rotate together with the frame  3 . As a result, when vehicle collision occurs, the first pinion gear  23  does not move together with the movable panel  5  due to impact upon the collision. Consequently, the following can be prevented: the movable panel  5  which is a heavy object is slammed shut by rotation of the first pinion gear  23  and therefore is damaged; and the position of the opened/closed movable panel  5  (i.e., the rotation angle of the first pinion gear  23 ) cannot be accurately determined by the ECU. 
     (Other Embodiment) 
     The present disclosure is not limited to the foregoing embodiment, and may have various configurations other than the foregoing. That is, in the foregoing embodiment, the example where the first driven member is the movable panel  5  and the second driven member is the shade  16  has been described. However, the present disclosure is not limited to such an example. For example, both of the first and second driven members may be movable panels  5  or shades  16 . Moreover, the first and second driven members are not limited to the movable panel  5  and the shade  16 . For example, the first and second driven members may be any members provided at the opening  2  of the vehicle, such as a deflector. 
     In the foregoing embodiment, the output shaft  52  of the motor  18  is connected to the drive gear  19  through the worm gear and the input gear  53  (i.e., a reduction gear), but the present disclosure is not limited to such a configuration. For example, the output shaft  52  of the motor  18  may be directly connected to the drive gear  19 . 
     In the foregoing embodiment, the engagement recessed parts  26   b  are formed at the upper surface of the movable clutch plate  26 , but engagement raised parts for fixing may be formed instead of the engagement recessed parts  26   b . In such a case, engagement recessed parts into which the engagement raised parts are fitted may be formed in the frame  3 . 
     In the foregoing embodiment, the clutch tooth parts  26   a  are formed at the lower surface of the movable clutch plate  26 , but the present disclosure is not limited to such a configuration. Engagement recessed parts may be formed at the lower surface of the movable clutch plate  26 , and clutch tooth parts to be fitted into the engagement recessed parts may be formed at the upper surface of the fixed clutch plate  25 . 
     In the foregoing embodiment, the first and second electromagnetic clutches  24 ,  44  are the engagement clutches, but the present disclosure is not limited to such a configuration. For example, the first and second electromagnetic clutches  24 ,  44  may be dry clutches each configured to transmit power by friction force between the fixed clutch plate  25 ,  45  and the movable clutch plate  26 ,  46 . That is, the first and second electromagnetic clutches  24 ,  44  may have any configurations as long as such clutches use magnetic force generated by the electromagnetic coil. 
     INDUSTRIAL APPLICABILITY 
     The present disclosure is useful for the drive device configured to drive the first and second driven members provided at the opening formed in the fixed roof of the vehicle. In particular, the present disclosure is useful in the case where at least one of the driven members is, e.g., the movable panel which is the heavy object. 
     DESCRIPTION OF REFERENCE CHARACTERS 
     
         
           1  Fixed Roof 
           2  Opening 
           3  Frame (Fixed Member) 
           3   a  Engagement Raised Part (Engagement Part) 
           5  Movable Panel (First Driven Member) 
           8  First Geared Cable (First Drive Cable) 
           9  Second Geared Cable (Second Drive Cable) 
           10  Drive Unit (Drive Device) 
           16  Shade (Second Driven Member) 
           18  Motor 
           19  Drive Gear 
           21  First Power Transmission Gear 
           22  First Output Shaft 
           23  First Pinion Gear 
           24  First Electromagnetic Clutch 
           25  Fixed Clutch Plate 
           25   a  Engagement Recessed Part (Engagement Part) 
           26  Movable Clutch Plate 
           26   a  Clutch Tooth Part (Clutch Engagement Part) 
           26   b  Engagement Recessed Part for Fixing (Fixing Engagement Part or First Fixing Means) 
           40  Second Gear Mechanism 
           41  Second Power Transmission Gear 
           42  Second Output Shaft 
           43  Second Pinion Gear 
           44  Second Electromagnetic Clutch 
           45  Fixed Clutch Plate 
           45   a  Engagement Recessed Part (Engagement Part) 
           46  Movable Clutch Plate 
           46   a  Clutch Tooth Part (Clutch Engagement Part) 
           46   b  Engagement Recessed Part for Fixing (Fixing Engagement Part or Second Fixing Means) 
           51  Worm Gear (Reduction Gear) 
           52  Output Shaft of Motor 
           53  Input Gear (Reduction Gear)

Summary:
[Problem] A drive unit ( 10 ) for driving, via a first and second geared cable ( 8, 9 ), a first and second member to be driven (sun roof and shade) provided to an opening part formed on the secured roof of a vehicle, wherein while being able to switch between a state in which the power from a motor ( 18 ) is transferred to both the first and second members to be driven and a state in which the power is selectively transferred to the first or second member to be driven, the member to be driven, in which the transfer of the power from the motor ( 18 ) is blocked, is prevented from moving during an impact when the vehicle collides in the selective transfer state. [Solution] The output path of the motor ( 18 ) is divided into a first and second output shaft ( 22, 42 ). Moreover, a first and second electromagnetic clutch ( 24, 44 ) for switching between connecting/disconnecting a first and second pinion gear ( 23, 43 ) to/from the first and second output shafts ( 22, 42 ) is provided, and each pinion gear ( 23, 43 ) is secured to a frame ( 3 ) so as to not be able to rotate when disconnecting from the clutches ( 24, 44 ).