Abstract:
In a vehicle roof system for closing and opening a roof opening ( 2   a ) formed in a fixed roof panel ( 2 ) of a vehicle with a moveable roof panel ( 4 ), an electric motor ( 24 ) mounted on a front edge of the roof opening actuates the moveable roof panel via a pair of push-pull cables ( 22 ). The drive section of at least one of the push-pull cable includes a bulging section bulging in a forward direction, and the elongated direction of the main body of the electric motor extends substantially in parallel with a sloping inboard side of the bulging section of the one push-pull cable. Therefore, the push-pull cable can be bulged forward without any restriction so that the push-pull cable can be laid out so as not to include any part having an unduly small radius of curvature. Therefore, a relatively friction free guidance of push-pull cables can be accomplished in actuating the moveable roof panel. Also, the oblique placement of the electric motor enables the electric motor to be placed in a laterally offset position, creating a room for installing an onboard device ( 30 ) between the front end of the fixed roof panel and front edge of the roof opening.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a vehicle roof system including a moveable roof panel and a drive unit for actuating the roof panel between a position to close an opening in a roof of a vehicle and a position to expose the opening. 
       BACKGROUND OF THE INVENTION 
       [0002]    Vehicle roof systems also known as sunroof systems are widely used in passenger vehicles for selectively opening and closing an opening formed in the roof of the vehicle. A typical vehicle roof system comprises a moveable roof panel and a drive unit for actuating the moveable roof panel between a position to close the opening and a position to expose the opening. A pair of guide rails are fixedly secured to the fixed roof panel, and extend along either lateral side of the roof opening, and the moveable roof panel is supported by these guide rails via sliders so as to be slidable in the fore and aft direction. An electric motor is provided centrally on the front edge of the roof opening, and a pair of push-pull cables connected to the corresponding sliders are actuated by the electric motor as required. 
         [0003]    The electric motor may be placed either on the front edge or rear edge of the roof opening. If the electric motor is placed on the rear edge of the roof opening, as this part lacks any stiff member, a rear frame is required to be added to the roof structure for supporting the electric motor. It is possible to do away with the rear frame by using highly stiff guide pipes for guiding the push-pull cables, but this also adds to the weight of the vehicle body, and causes some difficulty in the handling of the assembly including the electric motor and guide pipes. Based on such considerations, it is preferable to place the electric motor on the front edge of the roof opening. 
         [0004]    It is proposed in co-pending application US20100181805A1 (patent document 1) to mount an electric motor on the front edge of the roof opening, and use guide pipes (drive pipes and idle pipes) made of plastic material which are firmly retained by a front frame via pipe retaining members. 
         [0005]    Sometimes, in addition to the electric motor, onboard devices such as room lamps and electric switches are attached to the part of the roof surrounding the roof opening, and such devices are required to be placed so as not to interfere with the electric motor. In particular, a room lamp is provided adjacent to a central part of the front edge of the roof opening. To avoid the interference between the electric motor and room lamp, it was proposed in JP2001-130349A (patent document 2) to provide a sub frame below the electric motor for supporting a map lamp, a room lamp and vanity lamps, and combine the electric motor and sub frame as an assembly that can be installed in the vehicle roof as a single unit. 
         [0006]    However, according to the vehicle roof structure disclosed in patent document 2, the room lamp and electric motor are placed one above the other in an overlapping relationship in plan view so that the thickness of the vehicle roof (as measured from the lower surface of the roof lining and the upper surface of the roof panel) inevitably increases. To avoid this problem, it is conceivable to place the room lamp at a relatively forward position, and place the electric motor between the room lamp and the front edge of the roof opening. However, this necessitates the front edge of the roof opening to be placed more rearward than desired. If the roof opening is located too far back in the roof, the viewing angle of the vehicle occupant through the roof opening is so upright that the vehicle occupant&#39;s field of view is restricted, and the benefits of the sunroof system are diminished. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    In view of such problems of the prior art, a primary object of the present invention is to provide a vehicle roof system that can minimize the thickness of the vehicle roof while ensuring a relatively friction free guidance of push-pull cables for actuating the moveable roof panel. 
         [0008]    A second object of the present invention is to provide a vehicle roof system that allows the front edge of the roof opening to be brought highly close to the front end of the roof panel (or the upper edge of the windshield). 
         [0009]    A third object of the present invention is to provide a vehicle roof system that can create a space between the front edge of the roof opening and the front end of the fixed roof panel so that an onboard device such as a room lamp may be installed in the space without interfering with the component parts of the vehicle roof system. 
         [0010]    According to the present invention, such objects can be accomplished by providing a vehicle roof system for closing and opening a roof opening formed in a fixed roof panel of a vehicle with a moveable roof panel, comprising: a front frame secured to a lower surface of the fixed roof panel and extending laterally along a front edge of the roof opening; a pair of side frames secured to the fixed roof panel and extending longitudinally along a first side edge and a second side edge of the roof opening, respectively; a pair of guide rails fixedly secured to the respective side frames to guide the moveable roof panel for the closing and opening movements thereof; an electric motor attached to the front frame at a position laterally offset toward the second side edge of the roof opening, and having a main body elongated in a direction at an angle with respect to a lateral direction and a vertically extending output shaft fitted with a drive gear; and a pair of push-pull cables meshing with a front and rear side of the drive gear, respectively, and each including a drive section extending from the drive gear laterally along the front frame to the corresponding side frame and an idle section extending from the drive gear laterally along the front frame away from the drive section at least to a corresponding lateral end of the front frame; wherein the drive section of at least one of the push-pull cable includes a bulging section bulging in a forward direction, and the elongated direction of the main body of the electric motor extends substantially in parallel with a sloping inboard side of the bulging section of the one push-pull cable. 
         [0011]    As the elongated direction of the electric motor is aligned with a sloping section of the push-pull cable, the push-pull cable can be bulged forward without any restriction so that the push-pull cable can be laid out so as not to include any part having an unduly small radius of curvature. Therefore, a relatively friction free guidance of push-pull cables can be accomplished in actuating the moveable roof panel. Also, the oblique placement of the electric motor enables the electric motor to be placed in a laterally offset position, creating a room for installing an onboard device between the front end of the fixed roof panel and front edge of the roof opening. Therefore, in spite of the presence of such an onboard device, it still is possible to minimize the thickness of the vehicle roof. Furthermore, the front edge of the roof opening can be brought highly close to the front end of the roof panel (or the upper edge of the windshield) so that the vehicle occupant&#39;s viewing angle of the front edge of the roof opening can be minimized, and the attractiveness of the vehicle sunroof system can be enhanced. 
         [0012]    The bulging section of the one push-pull cable defines a smooth sinusoidal curve with a convex side thereof facing forward so that the frictional resistance to the push-pull cable may be minimized. According to a preferred embodiment of the present invention, the one push-pull cable meshes with the front side of the drive gear so that the electric motor may not be interfered by the idle cable section of the other push-pull cable. In this case, the drive section of the one push-pull cable crosses the idle section of the other push-pull cable. 
         [0013]    The drive section of the other push-pull cable may also be provided with a bulging section that crosses the idle section of the other push-pull cable twice so that the drive section of the other push-pull cable may also be guided in a relatively friction-free manner. Typically, the idle section of each push-pull cable extends into the corresponding lateral side of the roof opening along an outboard side of the drive section of the other push-pull cable. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Now the present invention is described in the following with reference to the appended drawings, in which: 
           [0015]      FIG. 1  is a simplified plan view of a vehicle roof system embodying the present invention; 
           [0016]      FIG. 2  is a sectional view taken along line II-II of  FIG. 1 ; 
           [0017]      FIG. 3  is a sectional view taken along line III-III of  FIG. 1 ; 
           [0018]      FIG. 4  is an enlarged fragmentary view of a front part of the vehicle roof system; 
           [0019]      FIG. 5  is a sectional view taken along line V-V of  FIG. 4 ; 
           [0020]      FIG. 6  is a sectional view taken along line VI-VI of  FIG. 4 ; 
           [0021]      FIG. 7  is a sectional view taken along line VII-VII of  FIG. 4 ; 
           [0022]      FIG. 8  is a sectional view taken along line VIII-VIII of  FIG. 4 ; and 
           [0023]      FIG. 9  is an enlarged view of the layout of the push-pull cables in the area adjacent to the electric motor. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]      FIG. 1  is a see-through plan view showing the vehicle roof system embodying the present invention. The illustrated vehicle roof  1  comprises a fixed roof panel  2  accounting for a large part of the vehicle roof  1  and formed with a rectangular opening  2   a  in a front part thereof, and a sunroof system  3  configured to selectively close and open the roof opening  2   a.    
         [0025]    A large part of this vehicle roof system is symmetric with respect to the central longitudinal plane of the vehicle body, and only one of two symmetric parts may be discussed in the following description where appropriate as the two parts are essentially identical to each other. In some places, such symmetric parts are denoted with a numeral with a suffix r or l as the case may be to indicate on which side of the vehicle body the parts in question are located. In other places, these parts are collectively denoted with the corresponding numeral without a suffix. 
         [0026]    The sunroof system  3  comprises a sunroof frame  10  fixedly secured to the roof panel  2  and surrounding the roof opening  2   a , a sunroof panel (moveable roof panel)  4  supported by the sunroof frame  2  so as to be moveable at least in the fore and aft direction (slide movement) and a drive unit  20  for actuating the sunroof panel  4  between a fully open position (rearmost position) and a fully closed position (front-most position). The sunroof system  3  of the illustrated embodiment is additionally configured to raise the rear end of the sunroof panel  4  from the fully closed position (tilt movement). 
         [0027]    The sunroof frame  10  includes a pair of side frames  11   l  and  11   r  extending along either lateral side of the roof opening  2   a , a front frame  12  extending between the front ends of the side frames  11   l  and  11   r  and a center frame  13  extending between intermediate parts of the side frames  11   l  and  11   r . The front frame  12  extends along the front edge of the roof opening  2   a , and the center frame  13  extends along the rear edge of the roof opening  2   a . Therefore, the rear ends of the side frames  11   l  and  11   r  extend rearward beyond the rear edge of the roof opening  2   a . The front frame  12  is C-shaped in plan view having an open side directed toward the roof opening  2   a . In the illustrated embodiment, the side frames  11   l  and  11   r  are made of extruded aluminum alloy, and the front and center frames  12  and  13  are made of extruded plastic material. 
         [0028]    Additionally referring to  FIG. 2 , a pair of panel brackets  5   l  and  5   r  extending in the fore and aft direction are attached to the lower side of the sunroof panel  4  along either lateral edge thereof. The panel brackets  5   l  and  5   r  are fitted with front sliders  6   l  and  6   r  and rear sliders  7   l  and  7   r , respectively, by which the sunroof panel  4  is slidably supported by the side frames  11 . The rear sliders  7   l  and  7   r  are connected to the corresponding panel brackets  5   l  and  5   r  via a cam mechanism that controls the sliding movement and tilting movement of the sunroof panel  4  under the actuating force of the drive unit  20 . 
         [0029]    A front roof rail  8  is attached to the lower side of the roof panel  2  and extends in parallel with the front frame  12  at a small distance ahead thereof. The front roof rail  8  is trough-shaped with a convex side facing upward so as to form a front roof frame  9  having a closed cross section in cooperation with the roof panel  2 . The front edge of the front roof frame  9  adjoins the upper edge of a windshield panel  27 . The front part of the roof panel  2  and windshield panel  27  slope downward toward the front part of the vehicle so as to jointly define a smooth outer contour. A roof lining  29  overlies the roof panel  2  from below, and defines an opening  29   a  slightly smaller than the roof opening  2   a  so that the edge of the opening  29   a  slightly extends into the roof opening  2   a  in plan view. A space defined between the roof panel  2  and roof lining  29  receives the main part of the sunroof system  3 . 
         [0030]    As best illustrated in  FIG. 3 , each side frame  11  is positioned between the roof panel  2  and roof lining  29 , and includes a drain trough section  11   a  having a U-shaped cross section to drain rainwater out of the sunroof system  3 , a cable guide section  11   c  located on the inboard side of the drain trough section  11   a  and defining a slot for guiding a push-pull cable  22  connected to the rear slider  7 , and a guide rail section  11   b  located on the inboard side of the cable guide section  11   c  and defining a slot facing outboard to guide the corresponding front slider  6  and rear slider  7 . 
         [0031]    Referring to  FIG. 2 , the side frames  11  are disposed horizontally so that the rainwater received in the drain trough section  11   a  may be drained either in the forward or rearward direction without overflowing when the vehicle is accelerating or decelerating. Accordingly, the roof lining  29  extends substantially horizontally in the region located behind the front edge of the opening  29   a , and is bent slightly downward in the region located ahead of the front edge of the opening  29   a  so as to conform to the contour of the lower surface of the roof panel  2 . A pair of sun visor units  31   r  and  31   l  for the vehicle operator and the passenger are mounted on the lower side of the part of the roof lining  29  located ahead of the front edge of the opening  29   a  as shown in  FIG. 4 . 
         [0032]    Referring to  FIG. 1 , the drive unit  20  includes an electric motor  24  attached to the lower surface of the front frame  12  in an rightwardly offset position and internally incorporated with a gear reduction unit (not shown in the drawings), a drive gear  23  attached to an output end of the electric motor  24 , and a pair of push-pull cables  22   r  and  22   l  each having one end connected to the corresponding rear slider  7 , and defining a driven rack gear  21  formed by spirally winding a steel wire around a steel core wire and meshing with the drive gear  23 . The electric motor  24  includes a main body elongated in the direction of a rotor shaft thereof (not shown in the drawings) and at an angle with respect to the lateral direction of the vehicle body. The rear and inboard end of the main body of the electric motor  24  is provided with a gear reduction mechanism which transmits the rotation of the rotor shaft of the electric motor  24  to the output shaft that supports the drive gear  23  and extends vertically. 
         [0033]    A map lamp unit  30  is attached to the front frame  12  via a bracket not shown in the drawing, and fitted into an opening  29   b  formed in the roof lining  29  at a laterally central part therefore ( FIG. 7 ) so that the map lamp unit  30  is received in a space defined between the fixed roof panel  1  and roof lining  29  but is exposed to the passenger compartment. Therefore, the map lamp unit  30  is located centrally adjacent to the front edge of the roof opening  2   a  while the electric motor  24  is placed laterally offset from the map lamp unit  30  so as not to interfere with each other. In particular, the electric motor  24  does not substantially overlap with the map lamp unit  30  when viewed from the front but substantially overlaps with the map lamp unit  30  when viewed from the side. See  FIGS. 7 and 8 . 
         [0034]    Each push-pull cable  22  includes a drive cable section  22   a  extending from the drive gear  23  to the corresponding rear slider  7  to transmit the drive force of the electric motor  24  to the rear slider  7 , and an idle cable section  22   b  extending from the drive gear  23  in the opposite direction from the drive cable section  22   a  without being subjected to any loading. The drive cable section  22   a  is linearly guided by the cable guide section  11   c  of the side frame  11 , and guided by a drive pipe  25  secured to the front frame  12  between the drive gear  23  and the front end of the cable guide section  11   c  along a curved path. The drive pipe  25  may be conveniently made of plastic material that allows the drive pipe  25  to be curved as desired without any difficulty. The idle cable section  22   b  is likewise guided by an idle pipe  26  secured to the front frame  12  along a partly curved path ( FIG. 5 ). As the electric motor  24  is offset in the rightward direction, a part of the idle pipe  261  (the part located to the right of the drive gear  23  in  FIG. 1 ) for the left push-pull cable  22   l  extends rearward from the right end of the front frame  12 , and the remaining part of the idle pipe  261  extends along the right side frame  11   r  ( FIG. 2 ). 
         [0035]    These guide pipes (drive pipes  25  and idle pipes  26 ) not only protect the push-pull cables  22  from moisture, dust and other foreign matters, but also control the deflection of the push-pull cable  22  as being pushed and pulled by the drive gear  23  so that the rear sliders  7  may be displaced in a prescribed relationship to the rotational angle of the drive gear  23 . The two push-pull cables  22   l  and  22   r  oppose each other in a mutually parallel relationship (both extending in the lateral direction) at the drive gear  23 , and are urged toward each other by spring members so that the rotational movement of the drive gear  23  may be transmitted to the rear sliders  7   l  and  7   r  in a properly synchronized relationship. In the illustrated embodiment, the push-pull cable  22  connected to the right lateral end of the sunroof panel  4  or the right rear slider  7   r  extends along the front side of the drive gear  23 , and the push-pull cable  22  connected to the left lateral end of the sunroof panel  4  or the left rear slider  7   l  extends along the rear side of the drive gear  23 . 
         [0036]    The sunroof panel  4  defines an outer contour continuously and smoothly connected to the roof panel  2  in the fully closed position thereof. When the electric motor  24  further pulls the push-pull cables  22  via the drive gear  23  from the fully closed position of the sunroof panel  4 , the rear end of the sunroof panel  4  is raised to place the sunroof panel  4  in a tilted up position by means of the cam mechanism incorporated in the rear sliders  7 . When the push-pull cables  22  are pushed from this state, the sunroof panel  4  is tilted down, and returns to the fully closed position. When the push-pull cables  22  are pushed from the fully closed position, the rear sliders  7  are displaced rearward, and this causes the sunroof panel  4  to be lowered below the roof panel  2  and to be moved rearward at the same time. When the sunroof panel  4  is displaced to the rearmost position thereof, the opening  2   a  is fully opened. When the push-pull cables  22  are pulled from this state, the sunroof panel  4  eventually closes the roof opening  2   a  reversing the aforementioned process. 
         [0037]    The structure of the vehicle roof around the front frame  12  is now described in the following with reference to  FIGS. 4 to 8 .  FIG. 4  shows the part of the roof  1  surrounding the front frame  12  in plan view with the roof panel  2  and sunroof panel  4  indicated by imaginary lines. Referring to  FIGS. 4 and 5 , the front frame  12  includes front planar part  12   a  extending under and in parallel with the roof panel  2  (thereby slightly sloping downward toward the front), a rear planar part  12   b  extending horizontally behind the front planar part  12   a  at a lower elevation, and a groove part  12   c  located between the front planar part  12   a  and rear planar part  12   b  and depressed more than these two parts. The groove part  12   c  includes a front wall  12   d , a rear wall  12   e  and a bottom wall  12   f , and the bottom wall  12   f  is lower than the front planar part  12   a  or the rear planar part  12   b.    
         [0038]    The front planar part  12   a  is provided with a drive pipe retaining groove  16   l  ( 16   r ) for retaining the drive pipe  25  and an idle pipe retaining groove  17   r  ( 17   l ) for retaining the idle pipe  26 , both opening out upward. A side wall of each pipe retaining groove  16  and  17  is provided with a plurality of clamps  18  including resilient tabs  18   a  resiliently clamping the drive and idle pipes  25  and  26  against the opposing side wall. The free end of each resilient tab  18   a  is formed with a barb that facilitates the insertion of the pipe  25 ,  26  into the groove  16 ,  17 , but opposes the dislodging of the pipe from the groove. Thereby, the drive and idle pipes  25  and  26  can be easily installed and removed as required, and are additionally prevented from deflecting once installed even when the drive and idle pipes  25  and  26  are made of relatively flexible plastic material and the push-pull cables  22  received therein are subjected to tensile and compressive forces. 
         [0039]    As shown in  FIGS. 4 and 6 , the front planar part  12   a  is formed with a through hole  15  at a part laterally offset to the right from the center for passing the drive gear  23  from below, and the two pipe retaining grooves extend along the front and rear sides of the through hole  15  both in the lateral direction (in a mutually parallel relationship). In particular, the drive pipe retaining groove  16   l  and the idle pipe retaining groove  17   l  for the left push-pull cable  22   l  extends along the rear side of the drive gear  23 , and the drive pipe retaining groove  16   l  r and the idle pipe retaining groove  17   r  for the right push-pull cable  22   r  extend along the front side of the drive gear  23 . 
         [0040]    As best shown in  FIG. 4 , the idle cable sections of the push-pull cables  22  extend along the corresponding side frames  11  on outboard sides of the adjacent drive cable sections of the other push-pull cables  22 . Therefore, it is necessary that the two push-pull cables  22  cross each other at least at one location. In that case, the left push-pull cable  22   l  that meshes with the rear side of the drive gear  23  is required to be more sharply bent than the right push-pull cable  22   r  that meshes with the front side of the drive gear  23  as the push-pull cable extends from the corresponding lateral end of the front frame  12  to the corresponding side frame  11 . 
         [0041]    According to the present invention, in addition to that the idle cable section of the left push-pull cable  22   l  crosses the drive cable section of the right push-pull cable  22   r  at one location P 1 , the drive cable section of the left push-pull cable  22   l  includes a bulging section bulging forward by crossing the idle cable section of the right push-pull cable  22   r  at two locations P 2  and P 3 . Thereby, the drive cable section of the left push-pull cable  22   l  which is otherwise required to be most sharply bent is allowed to curve more gradually by forming a bulging section that extend forward beyond the idle cable section of the right push-pull cable  22   r.    
         [0042]    Referring to  FIGS. 4 and 9 , the electric motor  24  is provided with a base plate  24   a  fixedly attached to the lower surface of the front planar part  12   a  of the front frame  12 , a gear reduction unit attached to the lower surface of the base plate  24   a  and a motor main body  24   b  received in a casing common to the gear reduction unit. The base plate  24   a  is rectangular in shape, and has a small thickness (vertical dimension). The base plate  24  is disposed so that the four sides thereof are in parallel with the lateral and longitudinal direction of the vehicle body. The motor main body  24   b  is approximately cylindrical in shape, and is rectangular in plan view. The axial line of the motor main body  24   b  is at an angle with the lateral direction of the vehicle body. 
         [0043]    The drive section of each push-pull cable is subjected to a greater loading than the idle section, and is therefore required to be free from a section of a small curvature of radius. Therefore, the drive section of the right push-pull cable  22   r  is provided with a bulging section that bulges forward as it extends from the section in parallel with the front frame  12  and a section in parallel with the side frame  11 . As shown in  FIG. 9 , the drive section of the right push-pull cable  22   r  includes a first linear section S 0  extending laterally (rightward) from the drive gear  23 , a first curved section S 2  (having a radius of curvature of R 1 ) connected to the right end of the first linear section S 0  and convex toward the rear, a second curved section S 3  (having a radius of curvature of R 2 ) connected to the right end of the first curved section S 2  and convex toward the front, and a second linear section S 4  extending from the right end of the second curved section S 3  in the longitudinal direction. These sections are connected in a smooth manner (without any discontinuity in the inclination or sloping angle). Thereby, the radius of curvature of the drive section of the right push-pull cable  22   r  is maintained above a prescribed limit over the entire length thereof, and a relatively friction-free guidance of the push-pull cable is enabled. 
         [0044]    In particular, as the motor main body  24   b  is placed adjacent to and in parallel to the inboard-side sloping section of the push-pull cable or the inboard side of the bulging section (which may include adjoining parts of the first and second curved section S 2  and S 3 ), the electric motor  24  can be placed in a compact manner without interfering with the bulging section of the push-pull cable that bulges forward. 
         [0045]    The drive pipe retaining grooves  16   l  and  16   r  are provided at a substantially same elevation as the front planar part  12   a  over the entire lengths thereof ( FIG. 5 ). On the other hand, the idle pipe retaining grooves  17   l  and  17   r  are at the substantial same elevation as the front planar part  12   a  only in the part adjacent to the through hole  15 , and slope progressively downward toward the both lateral sides of the vehicle body so that the idle pipe retaining grooves  17   l  and  17   r  are enabled cross under the drive pipe retaining grooves  16   l  and  16   r  without interfering with them ( FIG. 4 ). 
         [0046]    The front part of the front frame  12  of the front planar part  12  is provided with a plurality (four, in the illustrated embodiment) of mounting bosses  14   a  to  14   d  projecting upward and arranged laterally at an approximately regular interval. Each mounting boss is formed with a through hole for receiving a fastener such as a screw or clip that secures the front frame  12  to the roof panel  2  (via a bracket not shown in the drawings). As the front frame  12  is attached to the roof panel  2  at the four locations, the stiffness of the front frame  12  is ensured, and is prevented from excessively deforming or breaking when subjected to the force transmitted from the push-pull cables  22  even though the front frame  12  is made of light-weight plastic material. 
         [0047]    The groove part  12   c  of the front frame  12  is provided with a drain outlet  12   g  on each lateral end thereof for expelling the rainwater received in the groove part  12   c  to the drain system of the sunroof system  3  not shown in the drawings. The bottom wall of the drain outlet  12   g  is substantially at the same elevation as that of the groove part  12   c , and the height of the side walls of each drain outlet  12   g  is determined so as not interfere with the idle pipe  26  extending above the drain outlet  12   g.    
         [0048]    As shown in  FIGS. 4 ,  7  and  8 , the map lamp unit  30  is provided centrally on the front edge of the roof opening  2   a , and is received in the opening  29   b  formed in the roof lining  29  so as to face the interior of the passenger compartment  28 . The map lamp unit  30  is fixedly secured to the roof panel  2  via a bracket not shown in the drawings. The map lamp unit  30  may include map lamps for illuminating localized parts of the front seats, a room lamp for illuminating the entire passenger compartment  28  and a switch panel for turning on and off these lamps and controlling the sunroof system  3 , as a single assembly supported by a common frame. The main part of the map lamp unit  30  is received in the space between the roof lining  29  and roof panel  2 , and the lower surface of the map lamp unit  30  is substantially flush with the surface of the remaining part of the roof lining  29 . 
         [0049]    The map lamp unit  30  is located between the front wall  12   d  of the front frame  12  and the rear wall of the front roof frame  9  without interfering with them. In particular, in side view, the map lamp unit  30  is located ahead of the front wall  12   d  of the front frame  12 , and the rear end of the map lamp unit  30  may be located under the front planar part  12   a . Because the electric motor  24  is located so as not to overlap with the map lamp unit  30  in front view, the map lamp unit  30  may overlap with the electric motor  24  in side view without interfering with each other. By positioning the map lamp unit  30  so as to be partly located under the front planar part  12   a  of the front frame  12  and overlap with the electric motor  24  in side view, the distance between the front frame  12  and front roof frame  9 , in particular the distance between the front edge of the roof  1  to the front edge of the roof opening  2   a  of the roof panel  2  can be minimized so that the vehicle occupant&#39;s viewing angle of the front edge of the roof opening  2   a  can be minimized. The electric motor  24  is also located between the rear wall of the front roof frame  9  and the front wall  12   d  of the front frame  12 , and about a rear half of the electric motor  24  is located under the front planar part  12   a  of the front frame  12 . As the electric motor  24  and map lamp unit  30  do not overlap each other in plan view ( FIG. 4 ), the thickness of the roof  1  or the distance between the lower surface of the roof lining  29  and upper surface of the roof panel  2  can be minimized. 
         [0050]    Each sun visor  31  is located on the side (or the lower side) of the roof lining  29  facing the passenger compartment  28 , and is pivotable around a pivot shaft  31 X extending laterally between a stowed position closely overlying the lower surface of the roof lining  29  as indicated by the solid lines in  FIG. 6 , and a deployed position extending vertically downward from the pivot shaft  31 X as indicated by the imaginary lines in  FIG. 6  to shield the sunlight from the front from the view of the vehicle occupant. 
         [0051]    In particular, because the electric motor  24  is placed in a laterally offset position, one of the sun visors  31  is located under the electric motor  24  in the stowed position thereof in an overlying relationship in plan view, the sun visor  31  can shield or muffle the acoustic noises generated from the electric motor  24 . The roof lining  29  is formed with a pair of recesses  29   c  for at least partly receiving the corresponding sun visors  31  therein. The rear end of each recess  29   c  is located ahead of the front wall  12   d  of the groove part  12   c  of the front frame  12  so that the recesses  29   c  can be formed by making use of the space available above the upper surface of the corresponding parts of the roof lining  29 , and the protrusion of the sun visors  31  from the lower surface of the roof lining  29  can be minimized. 
         [0052]    Referring to  FIG. 4 , the leftmost mounting boss  14   a  is located between the drive pipe retaining groove  16   l  and idle pipe retaining groove  17   r  on the front planar part  12   a  of the front frame  12 , and the second mounting boss  14   b  from the left is located adjacent to the left end of the map lamp unit  30 . The third mounting boss  14   c  from the left is located adjacent to the right end of the map lamp unit  30  or between the map lamp unit  30  and electric motor  24 , and the rightmost mounting boss  14   d  is located adjacent to the right end of the electric motor  24  and between the drive pipe retaining groove  16   r  and idle pipe retaining groove  17   l  on the front planar part  12   a  of the front frame  12 . Therefore, two of the attaching points  14   a  and  14   d  are located between the two push-pull cables on either side of the middle crossing location P 2 . In the illustrated embodiment, the four mounting bosses  14   a  to  14   d  are arranged at an equal interval, but may also be located at irregular intervals. 
         [0053]    As the third mounting boss  14   c  is located between the map lamp unit  30  and electric motor  24 , the spacings between the adjacent mounting bosses  14   a  to  14   d  can be at least relatively uniform without causing any one of the spacings to be excessively great so that the front frame  12  is free from any low-stiffness region even though the front frame  12  is made of plastic material or other relatively flexible material. As the two of the mounting bosses  14   c  and  14   d  are provided on either side of the electric motor  24  in close proximity, the stiffness of the part of the front frame  12  adjacent to the electric motor  24  is particularly increased so that the front frame  12  is prevented from excessively deforming or breaking by the force transmitted from the electric motor  24  when actuating the push-pull cables  22  even though the front frame  12  is made of plastic material or other relatively flexible material. 
         [0054]    Although the present invention has been described in terms of a preferred embodiment thereof, it is obvious to a person skilled in the art that various alterations and modifications are possible without departing from the scope of the present invention which is set forth in the appended claims. For instance, the present invention is equally applicable to a sunroof system which is capable of only the slide movement, and also to a sunshade system which opens and closes a moveable roof panel in the form of a sunshade configured to open and close an opening provided in the roof lining. For actuating the sunroof or sunshade panel, rack belts and other cables capable of transmitting the actuating force can also be used, instead of the push-pull cables of the illustrated embodiment, without departing from the spirit of the present invention. 
         [0055]    The contents of the original Japanese patent application on which the Paris Convention priority claim is made for the present application as well as the contents of the prior art references mentioned in this application are incorporated in this application by reference.