Abstract:
A drive device for a roof module of a motor vehicle. A drive device of this type, the roof module comprising two movable roof parts, with longitudinally extended tension/compression means for transmitting drive to the roof parts which are driveable by a common drive motor via two output pinions, is known. The output pinions are oriented coaxially with respect to each other, and the output pinions are assigned a change-over device which sets the drive motor into operative connection alternatively with the one or the other output pinion.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the priority of the German patent application DE 102013212576.3, the disclosure of which is hereby incorporated into this application. 
     FIELD OF THE INVENTION 
     The invention relates to a drive device for a roof module of a motor vehicle, the roof module comprising two movable roof parts, with longitudinally extended tension/compression means for transmitting drive to the roof parts which are driveable by a common drive motor via two output pinions which are assigned to the tension/compression means for the movable roof part. 
     BACKGROUND OF THE INVENTION 
     A drive device of this type is known from DE 35 45 869 C2 or DE 198 23 730 A1. The roof module has two movable roof parts which are shiftable relative to the roof module between opening and closed positions with the aid of drive transmission cables. The drive transmission cables are driven by in each case one output pinion for each roof part, with the two output pinions being assigned to a common drive motor. In order to activate the two output pinions by means of the common drive motor, a distributing gearing is provided in DE 35 45 869 C2. In DE 198 23 730 A1, the transmission of drive from the common drive motor to one of the two output pinions is changed over via an electromagnetic change-over device. 
     SUMMARY OF THE INVENTION 
     It is the object of the invention to provide a drive device of the type mentioned at the beginning, which is constructed in a simple manner and is designed in a space-saving manner. 
     Movable roof parts within the context of the invention can be dimensionally stable roof parts or else flexible sheetlike structures, such as, in particular, shading structures for the roof module. Output pinions within the context of the invention are output elements which transmit driving forces to the corresponding tension/compression means in a form-fitting and/or frictional manner. The output pinions are particularly advantageously formed by gear wheels. The tension/compression means are preferably flexible drive transmission cables in the form of flexible shafts which convert a rotational movement of a corresponding output pinion into a longitudinal displacement of the corresponding drive transmission cable. The orientation according to the invention of the two output pinions coaxially with respect to each other permits a particularly space-saving arrangement of the output pinions and, accordingly, a compact assignment of the change-over device. An electric motor is preferably provided as the common drive motor. 
     In a refinement of the invention, the change-over device comprises a mechanical distributor gearing which comprises a planetary gearing. This is a robust and fail-safe embodiment. 
     In a further refinement of the invention, the distributor gearing comprises two mutually coaxial crown wheels which are arranged in a common plane and are in each case assigned to an output train. An output train is to be understood as meaning the transmission of the driving force from the common drive motor to one output pinion in each case. The crown wheels are gear wheels which have an annular toothed ring on the outer circumference of a circular end surface of the respective disk-shaped gear wheel. The two drive trains which lead into the drive pinions can be fixed independently of each other, i.e. kept at a standstill, by a corresponding adjustment element of the change-over device. 
     In a further refinement of the invention, the crown wheels are stoppable in an alternating manner via an adjustment element which is adjustable radially with respect to an axis of rotation of the crown wheels, in particular a toothed cam element. Depending in each case on the position, the toothed cam element engages in each case one toothed ring of the two crown wheels. The toothed cam element is kept in a stationary manner in the respective blocking position. 
     In a further refinement of the invention, a planet carrier of the planetary gearing is connected to an output pinion for rotation therewith. In a further refinement, one crown wheel is connected to a ring gear for rotation therewith, said ring gear meshing with planet wheels of the planet carrier. In a further refinement of the invention, the other output pinion is connected to the crown wheel and to the ring gear for rotation therewith. The two output pinions are arranged coaxially and directly axially adjacent to each other. Owing to the fact that the one output pinion is driven via the planet carrier and the other output pinion is driven via the planet wheels, which are mounted rotatably on the planet carrier, a particularly space-saving design of the distributor gearing is ensured. 
     In a further refinement of the invention, the crown wheel and the ring gear form an integral component. The component constitutes a gear wheel which is provided on one side with an axially protruding toothed ring and on the other side with a toothed ring projecting radially inward (with respect to an axis of rotation of the gear wheel). The planet wheels mesh with the radially inwardly projecting toothed ring. The axially protruding toothed ring is acted upon by the toothed cam element. The two crown wheels have toothed rings protruding coaxially with respect to each other in the same axial direction. The division of the two toothed rings is designed in such a manner that the toothed cam element which is adjustable radially with respect to the teeth of the toothed rings of the crown wheels permits a secure and form-fitting blocking for one of the two crown wheels in each case. 
     In a further refinement of the invention, the other output pinion is connected to the crown wheel and to the ring gear for rotation therewith. If the output pinion has not been stopped, the output train for said output pinion therefore runs via the planet carrier, the planet wheels, the ring gear and the crown wheel, with ring gear and crown wheel forming the integral gear wheel. 
     In a further refinement of the invention, the change-over device comprises at least one electromagnetically switchable coupling unit. The coupling unit is switched as a function of corresponding control signals for opening or closing the at least one roof part of the roof module. 
     In a further refinement of the invention, the output pinions are spaced apart coaxially with respect to each other, and the electromagnetically switchable coupling unit is arranged axially between the two output pinions. As a result, the coupling unit is positioned in a space-saving manner between the two output pinions. The changing over from the one output train to the other can take place in a particularly simple manner. 
     In a further refinement of the invention, the coupling unit has an axially movable coupling slide which is connected in a rotationally locked manner to a motor gearing of the drive motor, wherein the coupling slide is provided on opposite axial sides with magnetically effective coupling surfaces which interact with in each case one electrically activatable magnetic field in the region of the output pinion. The magnetic field can be generated by an electromagnetic coil in the region of each output pinion. Energizing of the electromagnetic coil causes the coupling slide to be attracted, and moves axially into the engagement position with the assigned output pinion. 
     In a further refinement of the invention, the output pinions and the coupling surfaces of the coupling slide have mutually complementary profiled surfaces which, when the coupling slide is coupled axially to in each case one output pinion, ensure a rotationally locked connection between coupling slide and output pinion. In the event of a corresponding axial displacement, the coupling slide engages in a form-fitting manner with the respective output pinion via the complementary profiled surfaces, and therefore torque can be transmitted from the motor gearing of the drive motor to the output pinion in a play-free manner. The motor gearing of the drive motor preferably has a gear wheel which coaxially surrounds the coupling slide and is connected in a rotationally locked manner to the coupling slide. The gear wheel is fixed in the axial direction. At the same time, however, the gear wheel does not obstruct the axial moveability of the coupling slide. 
     In a further refinement of the invention, a control unit which activates the change-over device as a function of an opening or closed state of the roof parts is provided. In the case of the change-over device which comprises the mechanical distributor gearing, the control unit activates the distributor gearing via the corresponding mechanical adjustment element in such a manner that one output train in each case can be blocked. In the case of the change-over device which contains the electromagnetically switchable coupling unit, activation takes place by means of an electric or electronic control unit, in both cases as a function of corresponding opening and closing operations of the movable roof parts of the roof module. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further advantages and features of the invention emerge from the claims and from the description below of preferred exemplary embodiments of the invention that are illustrated with reference to the drawings. 
         FIG. 1  shows schematically an illustration of a roof module for a passenger motor vehicle with an embodiment of a drive device according to the invention. 
         FIG. 2  shows, in an enlarged illustration, the drive device for the roof module according to  FIG. 1 . 
         FIG. 3  shows, in an exploded illustration, a part of the drive device according to  FIG. 2 . 
         FIG. 4  shows, likewise in an exploded illustration, a further part of the drive device according to  FIG. 2 . 
         FIG. 5  shows, in an enlarged exploded illustration, a distributor gearing of the drive device according to  FIGS. 2 to 4 . 
         FIG. 6   a  shows schematically an illustration of a partial region of the drive device. 
         FIG. 6   b  shows a further illustration of a partial region of the drive device similar to  FIG. 6   a.    
         FIG. 7  shows a top view of the drive device. 
         FIG. 8  shows, in an enlarged illustration, a section through the drive device according to  FIG. 7  along the intersecting line VIII-VIII in  FIG. 7 . 
         FIG. 9  shows, in a perspective illustration, a further embodiment of a drive device according to the invention for a roof module according to  FIG. 1 . 
         FIG. 10  shows, in a exploded illustration, a part of the drive device according to  FIG. 9 . 
         FIG. 11  shows a sectional illustration of the part of the drive device according to  FIG. 10  with hatching omitted. 
     
    
    
     DETAILED DESCRIPTION 
     A roof module  1  according to  FIG. 1  is inserted into a roof aperture in a roof region of a passenger motor vehicle and fitted there. The roof module  1  has a dimensionally stable supporting frame  2  which is provided on opposite longitudinal sides with dimensionally stable guide rails  5  for the shifting of a first, dimensionally stable roof part  3  in the form of a glass roof. In addition, a further roof part  4  in the form of a flexible shading structure, which is provided on the end side with a dimensionally stable pull-out profile, is displaceable along the guide rails  5 . The two roof parts  3 ,  4  are moved by a drive device  6 ,  7 . The drive device  6 ,  7  comprises drive transmission cables  7  which are designed as flexible shafts transmitting tension and compression. The flexible shafts are also referred to as threaded shafts, since the outer casing thereof is provided with a helical profiling. 
     In a first embodiment according to  FIGS. 2 to 8 , the drive device  6  comprises a mechanical distributor gearing which is accommodated in a housing. The distributor gearing is operatively connected to an electric drive motor  11  and transmits the driving forces of the drive motor  11  to two output pinions  8  and  9  which are in each case assigned to a pair of drive transmission cables  7 , as can be gathered from  FIG. 2 . The drive transmission cables  7  act laterally on the respective roof parts  3 ,  4  in order to shift the roof parts  3 ,  4  between the opening and closed positions thereof. The closed position in the case of the shading structure is the shading position. 
     The drive device  6  is provided in order alternatively to drive the two output shafts  8 ,  9 . For this purpose, a change-over device  10  which, in the embodiment according to  FIGS. 2 to 8 , comprises the mechanical distributor gearing is provided. The driving force of the drive motor  11  is divided there into two output trains, each of which is assigned one of the two output pinions  8 ,  9 . The change-over device  10  according to  FIGS. 3 to 8  has a housing  12 ,  13 ,  21  in which the distributor gearing is accommodated. The drive motor  11  has a drive shaft on which a drive pinion  22  is fastened ( FIG. 4 ). The drive pinion uses a gear wheel transmission to drive a worm wheel  20  which meshes with a drive gear wheel  14 , which is designed as a spur gear wheel, of the distributor gearing (see  FIGS. 4 and 6   a ). The drive gear wheel  14  is connected to a sun wheel  16  of a planetary gearing for rotation therewith. Coaxially with respect to the sun wheel  16 , a planet carrier  19  is mounted rotatably relative to the sun wheel  16  and the drive gear wheel  14 . The end of the planet carrier that is opposite the drive gear wheel  14  bears the output pinion  8  in a rotationally locked manner by means of a square pin. The end  33  of the planet carrier  19  protrudes outward through a housing cover  12  of the housing  12 ,  13 ,  21  coaxially with respect to a central axis of rotation of the distributor gearing (see  FIG. 8 ) such that the output pinion  8  is positioned outside the housing  12 ,  13 ,  21 . A part of the planet carrier  19  that is in the form of a circular disk has journals for a plurality of planet wheels  17 , as can be seen with reference to  FIGS. 3 and 8 . The planet wheels are mounted rotatably on the journals of the planet carrier  19 . All of the planet wheels  17  mesh with a serration of the sun wheel  16  which is mounted rotatably coaxially with respect to the central axis of rotation of the distributor gearing on a bearing sleeve protruding in an opposed manner to the end  33 . That end of the bearing sleeve which is opposite the output pinion  8  has a cavity which is open toward the end and is provided on the inside with tool engagement surfaces  31 . The tool engagement surfaces  31  serve in an emergency to enable emergency actuation of the distributor gearing and therefore of the input pinions  8 ,  9 , by means of a suitable tool, such as an Allen key or the like. 
     The planet carrier  19  is axially embedded in a crown wheel  18  which is provided with an axially protruding toothed ring  29  in the region of an end side. In addition, the crown wheel  18  is provided with a further, radially inwardly projecting toothed ring  30  level with the planet wheels  17 . The planet wheels  17  mesh with said internal toothing formed by the radially inwardly projecting toothed ring. In addition, a further crown wheel  15  which is connected in a rotationally locked manner via vertical journals  27  to the journals of the planet carrier  19  is embedded in the crown wheel  18 . A toothed ring  28  of the crown wheel  15  is arranged in the same radial plane—with respect to the central axis of rotation of the distributor gearing—as the toothed ring  29  of the crown wheel  18 . The crown wheel  15  is embedded axially in the crown wheel  18 , as can be gathered from  FIGS. 6   a  and  8 . The two toothed rings  28  and  29  of the two crown wheels  15  and  18  can be stopped alternately by an adjustment unit  12  which, via a threaded worm  25 , axially adjusts an adjustment element  23  in the form of a toothed cam element provided with a toothed cam  32 . The adjustment element  23  is guided in a linearly movable manner in the housing  12 ,  13 ,  21  in such a manner that a rotational movement of the threaded worm  25  results in a linear adjustment of the adjustment element  23 . The linear guide for the adjustment element  23  is oriented radially with respect to the central axis of rotation of the distributor gearing, as can be gathered from  FIGS. 6   a  and  8 . The orientation is undertaken in such a manner that the toothed cam  32  of the adjustment element  23  engages in each case in one of the two toothed rings  28 ,  29  of the crown wheels  15 ,  18 , depending on the adjustment position of the adjustment element  23 . The adjustment element  23  is not linearly adjusted directly by transmission of torque between the threaded worm  25  and adjustment element  23 . On the contrary, the threaded worm  25  is screwed to a threaded sleeve  26 , with the adjustment element  23  being pushed onto the outer side of said threaded sleeve and being displaceable relative to the threaded sleeve  26 . The displaceability of the adjustment element  23  on the threaded sleeve  26  is formed by two axial stops A which are fixed on the threaded sleeve  26 . In addition, the adjustment element  23  is held in a central position between the two stops A by two helical compression springs  24 . The adjustment element  23  is therefore mounted in a floating manner on the outer casing of the threaded sleeve  26 . Owing to the linear guidance of the threaded sleeve  26  in corresponding guide profilings of the housing  21 , a rotational movement of the threaded worm  25  inevitably results in a linear movement of the threaded sleeve  26 , as a result of which the adjustment element  23  is inevitably also entrained. The helical compression springs  24  are pretensioned and, in conjunction with the stops A, limit the adjustment distance of the adjustment element  23  on the threaded sleeve  26 . The adjustment distance of the threaded sleeve  26  itself is limited by corresponding revolutions of the threaded worm  25  of the adjustment unit  12 . The adjustment unit  12  has an electric motor as the adjustment drive. 
     If the radially outer toothed ring of the crown wheel  18  is then fixed by the toothed cam  32  of the adjustment element  23 , the output pinion  9  is inevitably blocked in respect of a rotational movement. Said output pinion is likewise stopped. Accordingly, a rotational movement of the drive gear wheel  14  that is caused by the drive motor  11  is transmitted via the sun wheel  16  to the planet wheels  17 , which roll along the stopped toothed ring  30  of the crown wheel  18  and thus cause the planet carrier  19  to rotate. As a result, the output pinion  8 , which is rotationally locked to the planet carrier  19 , inevitably also rotates. If, alternatively, the outer toothed ring  29  is then released and the inner toothed ring  28  of the crown wheel  15  is fixed by the adjustment element  23 , the following sequence of movement arises: owing to the stopping of the crown wheel  15 , the planet carrier  19  inevitably also stops, and therefore the output pinion  8  is blocked in respect of a rotational movement. A rotational movement of the drive gear wheel  14  results in a rotational movement of the sun wheel  16  which meshes with the planet wheels  17 . Since the planet carrier  19  is stopped, i.e. is blocked in respect of a rotational movement, the rotations of the planet wheels  17  inevitably, via the meshing with the toothed ring  30  located radially on the inside, bring about a rotational movement of the crown wheel  18 , which is connected in a rotationally locked manner to the output pinion  9 . Accordingly, the output pinion  9  is caused to rotate. 
     The toothed cam element  32  of the adjustment element  23  can also stop the two toothed rings  28  and  29  simultaneously. The two output pinions  8 ,  9  are then automatically blocked in respect of a rotational movement. Finally, the toothed cam element  32  of the adjustment element  23  can also release the two toothed rings  28  and  29  in respect of a rotational movement. In this position, the drive gear wheel  14  drives the two output trains of the two output pinions  8 ,  9 . 
     In the embodiment according to  FIGS. 9 to 11 , a drive device  6  is basically constructed in the same manner as the drive device  6  according to  FIG. 1 . In order to avoid repetitions, reference is therefore made to the explanations with regard to  FIG. 1 . The substantial difference is that, in the case of the embodiment according to  FIGS. 9 to 11 , the change-over device  10   a  comprises an electromagnetically switchable coupling unit. This drive device is also again provided with two output pinions  8   a ,  9   a  which are arranged coaxially with respect to each other and are operatively connected to corresponding drive transmission cables  7   a  in order to permit corresponding shifts of the roof parts  3 ,  4 . The two output pinions  8   a ,  9   a  are spaced apart coaxially with respect to each other—with respect to a central axis of rotation of the change-over device  10   a . The change-over device  10   a  has a coupling unit  34  to  38 . The coupling unit is connected in a rotationally locked manner to a drive gear wheel  14   a  which surrounds the coupling unit coaxially with respect to an axis of rotation of the output pinions  8   a ,  9   a . The drive gear wheel  14   a  is mounted axially in the center between the output pinions  8   a  and  9   a . For this purpose, housing bearing supports G which prevent displacement of the drive gear wheel  14   a  coaxially with respect to the axis of rotation of the output pinions  8   a ,  9   a  are provided. Guide members  34  of the coupling unit are connected in a rotationally locked manner to the drive gear wheel  14   a , said guide members guiding a guide slide  35  in an axially movable manner between each other. The coupling slide  35  is mounted in a rotationally locked, but axially movable manner in the guide channel formed by the guide members  34 . The coupling slide  35  protrudes towards both axial end sides beyond the guide members  34 . The coupling slide  35  is provided with one magnetizable coupling disk  36 ,  37  on each of said axial end regions. Each coupling disk  36 ,  37  has an axially outwardly protruding coupling extension  38  which can enter in a form-fitting or frictional manner into a respective coupling receptacle  39  of the assigned output pinion  8   a ,  9   a.    
     In addition, the end side of each output pinion  8   a ,  9   a  opposite the coupling disk  36 ,  37  is assigned an electromagnetic coil  41  which can generate a magnetic field which can draw the respective coupling disk  36 ,  37  axially against the assigned output pinion  9   a ,  8   a  and can thus produce a rotationally locked connection between the coupling slide  35  and the output pinion  8   a ,  9   a . In the illustration according to  FIG. 11 , the coupling slide  35  is held in an intermediate position in which said coupling slide is operatively connected to the two output pinions  8   a ,  9   a . This intermediate position can be maintained by springs (not illustrated). As soon as one of the two electromagnetic coils  41  is then energized, the magnetic field which has been produced inevitably draws the coupling slide  35  in the direction of the output pinion  8   a ,  9   a  of the activated coil  41 . As a result, the coupling extension  38  is inevitably disengaged in the region of the opposite output pinion because of the axial displacement of the coupling slide  35 , and therefore only one of the two output pinions  8   a ,  9   a  is still driven. 
     A control unit is provided both for the adjustment of the adjustment unit  12 , in the embodiment according to  FIGS. 2 to 8 , and for the energizing of the electromagnetic coils  41  according to  FIGS. 9 to 11 , but said control unit is not specifically illustrated for the two embodiments.