Abstract:
The invention relates to a device for adjusting a vehicle seat, the frame structure ( 4, 5, 6 ) of which can be adjusted using drive motors ( 40 ) having presupported gear units ( 39 ), and the vehicle seat is accommodated on two seat rails ( 1, 2 ) arranged parallel to each other. The frame structure ( 4, 5, 6 ) of the vehicle seat can be adjusted spherically using lifting elements ( 8, 9, 10 ) in two planes separated from each other.

Description:
BACKGROUND OF THE INVENTION 
   In general, passengers in motor vehicles can only adjust their seat position statically in advance. The seat position is usually not adjusted during the ride. The seat position of the vehicle passengers does not adapt to the driving situations encountered. 
   In previously known and presently common motor vehicle systems, the vehicle passengers select the seat position in the vehicle on an individual basis that they perceive to be the most favorable and comfortable before the trip begins. During the trip, the vehicle passengers are generally subjected to transverse forces resulting from lateral acceleration, when travelling around corners, for example. Moreover, transverse forces occur, which can result from braking and decleration phases during the ride. During the ride, transverse stresses arise between the cushions of the vehicle seats and the vehicle passengers due to the dynamic forces which are a function of the driving situation and which have an effect on the passengers, which transverse stresses can be perceived by the vehicle passengers as very uncomfortable. In particular when the level of the transverse stresses exceeds the respective personally acceptable threshold of the vehicle passengers. 
   SUMMARY OF THE INVENTION 
   Using the proposed solution according to the invention, the vehicle seat can be adjusted in braking and deceleration phases during the ride in its front section as a function of the degree of deceleration determined by the sensor technology in a fashion that counteracts the force that occurs. In the presence of lateral acceleration forces occurring necessarily during cornering as a result of centrifugal force, the vehicle seat, as a result of its three-point mounting, can be tipped around its longitudinal axis toward the center of the curve in order to counteract the centrifugal forces that occur. When cornering to the right, for example, the left lifting element is extended further upward in relation to the right lifting element in order to bring about a tilting of the vehicle seat around its longitudinal axis. 
   The lifting elements underneath the frame structure support this in the fashion of a three-point mounting, whereby a lifting element located in the center is provided on the front side of the frame structure, and the adjustment of the frame structure around the longitudinal axis of the motor vehicle oriented parallel to the vehicle axis can take place by way of two independently controllable lifting elements located in the rear section of the frame structure. 
   To accommodate suddenly-occurring crash forces, the lifting elements can be connected with each other by way of space rods. By arranging the space rods underneath the frame structure carrying the vehicle seat, the vehicle seat can be moved upward and downward in an approximately straight line; in addition, the vehicle seat is secured against rotation in relation to its vertical axis as a result of the space rod arrangement. The diagonals of the space rods also allow the forces occurring in a crash to be directed into the vehicle chassis. 
   The lifting elements, on the one hand, are provided with self-locking gears between drive motor and drive spindles. Moreover, a spring element arrangement is provided underneath the spindle nut. The spring elements can be coil springs connected in parallel, or they can be designed as spring packs—they support the drives of the lifting elements for the frame structure during its upwardly directed motion. To make the up-and-down motion possible, the lifting elements comprise inner and outer tubes that are inserted into each other in telescoping fashion. The tube arrangement comprises a threaded spindle that can be driven by the drive motor, the spindle nut of which is limited in its lower position by the block length of the spring elements, and in its maximum extended position by fixing straps provided on the outside of the lifting element. 
   Using the further proposed method for adjusting the frame structure of a vehicle seat according to the invention, the lifting elements that accommodate the frame structure of the vehicle seat are controlled sensor-dependently in such a fashion that the vehicle seat is adjusted in such a way as to counteract the forces occurring as a function of the driving situation. This can be carried out, on the one hand, by way of a pitching motion of the vehicle seat initiated by the sensor technology when the vehicle brakes are operated; on the other hand, the vehicle seat can be tilted toward the center of the curve around its longitudinal axis parallel to the longitudinal axis of the vehicle during cornering. In addition to an electronic actuation of the lifting elements of the frame structure underneath the vehicle seat, these can also be integrated in the hydraulic system—such as the power steering system—of the vehicle. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     The invention will be described in greater detail below using the diagram: 
       FIG. 1  shows the front view of a frame structure arranged on three lifting elements. 
       FIG. 2  shows a perspective top view of the three-point mounting of the frame structure. 
       FIG. 3  shows a top view of the frame structure with space rods. 
       FIG. 4  shows the view of the lifting elements with flange-mounted, self-locking gears and drive motors. 
       FIG. 5  shows the lifting elements in various operating positions. 
       FIG. 6  shows the perspective diagram of a forked space rod, including lifting element, and 
       FIG. 7  shows the schematic diagram of the drive controls for multiple lifting elements. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  shows the front view of a frame structure supported on the lifting elements. 
   The frame structure  4 ,  5 ,  6  is formed out of side sections  4 ,  5  that are connected with each other by way of the cross strut  6 . A lifting element  8  which is supported on a section  3  is located in the center under the cross strut  6 . The two seat rails  1 ,  2  extending perpendicular to the plane of the diagram are connected with each other by way of the section  3 . A space rod  7  extends between the first lifting element  8  and the two rear lifting elements  9 ,  10 , while the two lifting elements  9 ,  10  shown in the background are connected with a further bar-shaped space rod  11  running between these. The lifting elements  8 ,  9  and  10 —each shown here provided with an electric drive motor  40 —comprise telescopically extendable guide tubes  12  and  13 . The guide tubes  12 ,  13  are provided with fixing straps  14 , the eyes  19  of which are hung on a bolt  15 , in order to limit the maximum possible extension position of the inner guide tube  13  out of the outer guide tube  12 . Each of the fixing straps  14  of the lifting elements  8 ,  9  and  10  is accommodated on a bolt  37  at lower fixing strap immobilization points  36 . 
   The front lifting element  8 , anchored on the front part of the frame structure  4 ,  5 ,  6  in the center of the cross strut  6 , is supported on the section  3 , while the two rear lifting elements  9  and  10  are accommodated on the seat rails  1 ,  2 . The diagonally running space bar  11 , which connects the upper part of the lifting element  10  with the foot of the lifting element  9 , is arranged between the rear lifting elements  9 ,  10 . Each of the lifting elements  8 ,  9  and  10  is connected with the frame structure  4 ,  5  and  6  by way of an elastically designed bearing element  21 —not shown here, however. 
   A pitching motion of the frame structure  4 ,  5 , and  6  can be brought about in that the inner guide tube  13  of the front lifting element  8  extends, and the frame structure  4 ,  5 ,  6  swings horizontally perpendicular tot he plane of the diagram around the pivot points of the rear lifting elements  9  and  10 . When the vehicle is driven around a corner, the innermost lifting element  9  or  10  can be lowered, and the outermost lifting element  9  or  10  can be extended, in order to tilt the frame structure  4 ,  5 ,  6 —including the vehicle seat accommodated on this-toward the center of the curve. In order to make the tipping motion of the frame structure  4 ,  5  and  6  around the longitudinal axis possible, a length compensator is provided on the space rod  11 , for example in the shape of a telescopic rod guide of two rod-shaped elements slid into each other. The same applies for the space rod  7 , which is fastened on the bolt  15  of the front lifting element  8  and which is bolted to the seat rails  1 ,  2  at its two rear forked ends in such a way that a pitching motion of the frame structure  4 ,  5 , and  6  around the pivot points formed by the two rear lifting elements  9 ,  10  is still possible. 
   Each of the lifting elements  8 ,  9  and  10  has a lifting range of approximately 50 mm; with consideration for the arrangement of the three lifting columns  8 ,  9  and  10  in relation to each other, the frame structure  4 ,  5 , and  6  can be tilted by approximately 10° to the right or the left. The pitch angle of the frame structure  4 ,  5  and  6  around the rear pivot points on the lifting elements  9  and  10  is 10° to the front and approximately 10° to the rear. Using the drive motors  40 , which are provided at the feet of each of the lifting elements  8 ,  9  and  10 , and the gears  39 , an adjusting time of 3.85 seconds is realized, starting from the center position of the frame structure  4 ,  5 , and  6  with an extension height of approximately 25 mm and adjusting speeds of 6.5 mm/s. 
   The diagram according to  FIG. 2  provides a perspective top view of a three-point mounting of the frame structure. 
   For illustration purposes, one of the side sections  4 ,  5  has been left out, in order to expose the structural components located behind it. A seat bracket  34 ,  35  in the form of an angled sheet-metal section is fastened to each of the two rear lifting elements  9 ,  10 , to which the side sections  4 ,  5  of the connected frame structure  4 ,  5 ,  6  are fastened. The cross strut  6 , situated in the front section of the frame structure  4 ,  5 ,  6 , is supported in the center by the front lifting element  8 , because this makes the pitching motion of the frame structure  4 ,  5 , and  6  around the two rear lifting elements  9 ,  10  possible. On the rear lifting element  9 —which is shown partially exposed-it can be seen that its threaded spindle  23  is enclosed by two spring elements  17 ,  18  that form a spring Pack and are inserted into each other and connected in parallel, which spring elements  17 ,  18  support the upward motion of the threaded nut which is used as a positioning block  28  traveling along the lifting spindle  23 , which threaded nut preloads the spring elements  17 ,  18  in its lowered position, compressed to block length. 
   The space rod  11  shown here in simplified form is fastened on one side to the upper bolt  15  of the lifting element  10 , and, on the other side, to the motor mount  22  of the lifting element  9 . The lifting elements  8 ,  9  and  10  are all provided with rings  38  that constrict the fixing straps  14 ; the fixing straps  14  are fastened to the bolt  15  and the bolt  37  by means of the eyes  19  and limit the extension motion of the inner guide tube  13  out of the outer guide tubes  12 . The space rods  7 ,  11  connecting the lifting elements  8 ,  9  and  10  with each other make possible a coordinated, straight-line course of positioning movement of the frame structure  4 ,  5 ,  6  from top to bottom and vice-versa. Using the space rods  7 ,  11 , strong forces occurring in the case of an accident can be directed into the undercarriage of the vehicle chassis. Moreover, the space rods  7 ,  11  prevent the frame structure  4 ,  5 ,  6  from rotating around its vertical axis and absorb transverse forces that occur. To stiffen the bottom section of the frame structure  4 ,  5 ,  6 , the motor mounts  22  are flange-mounted on the side rails  1 ,  2  by way of fastening brackets  33 . 
     FIG. 3  shows a top view of the frame structure  4 ,  5  and  6  supported at each of three points by the lifting elements  8 ,  9  and  10 . 
   The course of the space rods  7 ,  11  between the individual lifting elements  8 ,  9  and  10  is apparent in the top view. The tiltable and horizontally-swingable frame structure  4 ,  5 , and  6  is located above the seat rails  1 ,  2  connected by the cross member  3 . Each of the upper ends of the rear lifting elements  9  and  10  is provided with a seat bracket  34 ,  35 , on which the side sections  4 ,  5  are flange-mounted to accommodate the vehicle seat. A separate drive  40  is assigned to each of the lifting elements  8 ,  9  and  10 ; the seat rails  1  and  2  provided beneath the frame structure  4 ,  5 ,  6  are bolted to each other by way of fastening brackets  33  in order to stiffen the structure. The space rod  7  is bolted in rotatable fashion to the seat rails  1 ,  2  in the rear section so that the frame structure  4 ,  5 ,  6  can execute pitching motions around its rear pivot points at the rear lifting elements  9  and  10 . 
     FIG. 4  shows a multiside view of the lifting elements  8 ,  9  or  10 . 
   The lifting elements  8 ,  9  or  10  are designed as compact units, which, thanks to their telescoping tubes  12 ,  13  can cover an adjusting range of between 50 mm and 60 mm; the fixing straps  14 , which make the maximum extension motion possible, are hung by way of eyes  19  on the bolts  15 ,  37  provided on both the top and bottom. An elastic bearing element  21  is located on the upper end of the inner guide tube  13 , with which the respective lifting elements  8 ,  9  or  10  can be secured to the frame structure  4 ,  5 ,  6 . In the lower section of the lifting elements  8 ,  9  or  10 , a drive motor  40  is connected with a self-locking drive formed by pre-supported gears  39  by way of a motor mount  22 , by way of which the threaded spindle  23  located inside the lifting element  8 ,  9  or  10  can be set into rotation. The electrical connections  29  of the drive motor  40  can be identified above the drive motor  40 , with which the drive motor  40  can be connected to the 12 V on-board power supply network. 
     FIG. 5  shows the diagram of lifting elements in various operating positions. 
   The inner guide tubes  13  of the lifting elements  8 ,  9  or  10  comprise an upper, elastically designed bearing element  21 , with which they are connected with the respective components of the frame structure  4 ,  5 ,  6 . The section  20  is intended here to represent one of the components of the frame structure  4 ,  5 ,  6 . The inner guide tube  13  is supported on the top side of the positioning block  28  designed as a threaded nut. The threaded spindle  23 , which is set into rotation by way of the presupported gears  39  and the drive motor  40 , extends into the cavity  24  in the inner guide tube  13  and is acted upon from below by spring elements  17 ,  18 . 
   In the position labelled “ 25 ”, one of the spring elements  17 ,  18  connected in parallel, which can be designed as coil springs, is compressed to block length and thereby determines the lower position of the lifting elements  8 ,  9  or  10 . The positioning block  28  is enclosed by the outer guide tube  12  in a such a fashion that it is secured against rotation and it moves in a middle operating position labelled “Position  26 ”, for example, via rotation of the threaded spindle  23 . In this middle position  26 , the bearing element  21  is extended upward 25 mm, for example, out of its lowest position. Accordingly, a lifting element  8 ,  9  or  10  in Position  26  has access to an adjusting range of ±25 mm in both directions. The two coil springs  17 ,  18  connected in parallel support the positioning block  28  in its upward motion along the threaded spindle  23 . The maximum extension position of the inner guide tube  13  out of the surrounding outer guide tube  12  is limited by the full tautness of the fixing straps  14  provided between the guide tubes  12 ,  13 . In the maximum position labelled “ 27 ”, the positioning block  28  is moved in its maximum position along the threaded spindle  23 , and the spring elements  17 ,  18  have assumed their released position. The spring system connected in parallel relieves the spindle arrangement as it moves upward. In the case of the front lifting element  8 , the maximum position  27  corresponds to a horizontal-swing angle of the vehicle seat surface of approximately 8 degrees, based on the rear supporting points of the frame structure  4 ,  5 ,  6  on the two rear lifting elements  9  and  10 . This position can be created during the ride, for example, by way of the sensor technology during braking or during deceleration phases, in order to reduce the deceleration forces acting on the vehicle passengers. The same applies for the rear lifting elements  9 ,  10  of the frame structure  4 ,  5 ,  6 . When the vehicle travels around a corner, for example, the innermost lifting element  9  or  10  in the rear section of the frame structure  4 ,  5 ,  6  is moved into Position  25  as shown in  FIG. 5 , while the outermost lifting element  9  or  10  assumes a middle Position  26  as shown in  FIG. 5 . As a result, the frame structure  4 ,  5 ,  6  accommodating the vehicle seat is tilted around its longitudinal axis during the ride. 
   Using the support of the frame structure  4 ,  5 ,  6  configured as three-point mounting, a spherical adjustment of the vehicle seat during the ride can be achieved, which is carried out as a function of the driving situation detected by the sensor technology, in order to reduce the transverse stresses occurring between the seat surface and the vehicle passengers. 
     FIG. 6  shows a perspective diagram of lifting element and sectional space bar. 
   The lifting element  8 ,  9  or  10  has an elastic bearing element  21  accommodated between two fastening brackets on the top side of its inner guide tube  13 . The bolts  15 ,  37  can be identified on the lifting element  8 ,  9  or  10 , in which the fixing straps  14  with their eyes provided on the ends are hung, moreover the electric drive  40  generating the spindle motion. Instead of an electric drive  40 , the lifting elements  8 ,  9  or  10  can also be integrated in the hydraulic system of such motor vehicles that are equipped with power steering. In such a design variant, a lateral sway of the vehicle seats could be coupled with the steering motions, for example. 
     FIG. 6  shows the configuration of the space rod  7 , which is fastened to the front lifting element  8  with its bearing fork  31  and is bolted to the seat rails  1 ,  2  with the corner piece  30  provided on its ends. The connection of the space rod  7  with the seat rails  1 ,  2  is carried out in such a way that the space rod  7  follows the pitching motion of the frame structure  4 ,  5 ,  6  around the rear pivot points on the lifting elements  9 ,  10  of the frame structure  4 ,  5 ,  6 . In other words, it is supported rotatably on bearings on the respective seat rails  1 ,  2 . 
     FIG. 7  shows the control of the electric drive motors  40  in a greatly simplified form. 
   The variant shown here for the three motors  40  is provided when the frame structure  4 ,  5 , and  6  is supported on bearings at three points. Each of the drives assigned to each of the lifting elements  8 ,  9 , and  10  is controlled as a function of the measured accelerations a x  and a y  according to the driving situation. A two-axis acceleration sensor  41  can be used for this purpose, which contains a first acceleration axis  42  for measurement of the acceleration a x  in X direction, when the vehicle accelerates or decelerates. The curve acceleration a y  is determined in a further axis  43 . 
   The values of the accelerations a x , a y  are transmitted to the control unit  44 , with which each of the drive motors  40  of the elements  8 ,  9  and  10  is controlled in accordance with the driving situation determined by the acceleration measurements. The control unit can be advantageously provided with semiconductor outputs  46 , with which a respective, speed-controlled control can be carried out. Moreover, the control unit  44  is connected with a control device  45 . 
   REFERENCE SYMBOL LIST 
   
       
         1  Seat rail 
         2  Seat rail 
         3  Cross member 
         4  Side section 
         5  Side section 
         6  Cross strut 
         7  Space rod 
         8  Lifting element, front 
         9  Lifting element, rear 
         10  Lifting element, rear 
         11  Space rod 
         12  Guide tube, outer 
         13  Guide tube, inner 
         14  Fixing strap 
         15  Bolt 
         16  Spindle nut 
         17  Inner spring 
         18  Outer spring 
         19  Eye 
         20  Section 
         21  Elastic bearing element 
         22  Motor mount 
         23  Threaded spindle 
         24  Cavity 
         25  Block length position 
         26  Extended position 
         27  Maximum position 
         28  Positioning block 
         29  Electrical connection 
         30  Corner piece 
         31  Bearing fork 
         32  Hole 
         33  Fastening bracket 
         34  Seat bracket 
         35  Seat bracket 
         36  Lower fixing strap immobilization point 
         37  Bolt 
         38  Ring 
         39  Gears 
         40  Drive motor 
         41  Acceleration sensor 
         42  Acceleration a x    
         43  Corner acceleration a y    
         44  Control unit 
         45  Control device 
         46  Semiconductor output