Patent Publication Number: US-2021178942-A1

Title: Vehicle seat having a suspension unit for cushioning rolling and vertical suspension movements

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of German Patent Application No. 10 2019 134 234.1 filed Dec. 13, 2019, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The invention relates to a vehicle seat having a suspension unit for cushioning the rolling and vertical suspension movements of the vehicle, wherein the vehicle seat has a vehicle seat upper part and a vehicle seat lower part, wherein the vehicle seat upper part and the vehicle seat lower part are connected by means of the suspension unit so that the vehicle seat upper part and the vehicle seat lower part are movable relative to one another, wherein the suspension unit comprises a scissor arrangement having a first scissor arm and a second scissor arm. 
     BACKGROUND 
     Vehicle seats having roll and vertical suspensions are known from the prior art; for example, WO 2014/176130 A discloses a roll suspension which can cushion rolling movements of the vehicle or the vehicle seat. However, such a rolling movement, as shown in the prior art, is very complex to implement in terms of design, requires many actively controlled components, and takes up a large amount of space. 
     SUMMARY 
     The object of the present invention is therefore to provide a vehicle seat having a suspension unit for cushioning rolling and vertical suspension movements, which is constructed in a simpler manner than that shown in the prior art and which has improved vibration comfort for the person sitting on the vehicle seat. 
     The core idea of the present invention is to provide a vehicle seat having a suspension unit for cushioning the rolling and vertical movements of the vehicle, wherein the vehicle seat has a vehicle seat upper part and a vehicle seat lower part, wherein the vehicle seat upper part and the vehicle seat lower part are connected by means of the suspension unit so that the vehicle seat upper part and the vehicle seat lower part are movable relative to one another, wherein the suspension unit has a scissor arrangement having a first scissor arm and a second scissor arm, wherein the suspension unit is rotatably connected about a first axis of rotation to the vehicle seat lower part and comprises a spring element support and a first spring element, wherein a displacement element is provided which is mounted displaceably relative to the vehicle seat lower part, wherein the first spring element is connected on the one hand to the displacement element and on the other hand to the spring element support, which is preferably rotatably connected about a second axis of rotation to the first scissor arm and rotatably connected about a third axis of rotation to the second scissor arm. The first spring element is preferably arranged at a first angle to a vehicle seat width direction and at a second angle to a vehicle seat height direction. The first angle and the second angle are preferably connected in such a way that the second angle corresponds to 90°—first angle. 
     A rolling movement is understood here to mean a rotational movement of the vehicle seat about an axis of rotation which is arranged to run in the vehicle seat longitudinal direction. 
     The first axis of rotation is therefore particularly preferably arranged parallel to the vehicle seat longitudinal direction. 
     According to a preferred embodiment, it is also provided that the vehicle seat upper part and the vehicle seat lower part can be cushioned or moved or shifted relative to one another by means of the suspension unit. 
     According to a particularly preferred embodiment, the first spring element is preferably one selected from an air spring and a mechanical spring. This also applies to possible other spring elements. 
     Due to the displacement of the displacement element, according to the invention the spring element is moved in its position in space through the connection of the spring element to the displacement element. The spring element has, for example, a first end and a second end, wherein the first end is connected to the spring element support and the second end is connected to the displacement element. As a result of the displacement of the displacement element, the second end of the spring element is displaced relative to the vehicle seat lower part, as a result of which an angle at which the spring element is positioned with respect to at least one of the coordinate directions of vehicle seat longitudinal direction, vehicle seat width direction and vehicle seat height direction is changed, whereby a change in the spring characteristic can be achieved. 
     By changing the respective angle of attack, the vertically acting force components of the respective spring element are changed. 
     In particular, the first spring element is arranged to run in the direction of the first angle and of the second angle, i.e. the first spring element is arranged to run obliquely as seen in a standard coordinate system. 
     The standard coordinate system is formed from the vehicle seat longitudinal direction, the vehicle seat width direction and the vehicle seat height direction, which are each arranged at a right angle to one another. 
     Because the first spring element is connected to the spring element support and the displacement element, it can be concluded that the first angle and the second angle are a function of the spring position of the vehicle seat. By a suspension movement, which can be a rolling and/or vertical suspension movement, the position of the spring element support changes in space, so that a first end of the first spring element also changes its position in space, wherein a second end of the first spring element, which is connected to the vehicle seat lower part, is not changed in its position. This means in particular that the first angle and the second angle are not constant during a suspension movement of the vehicle seat. In a neutral position, which means that the vehicle seat is not subject to any suspension movement, i.e. there is no relative movement of the vehicle seat upper part with respect to the vehicle seat lower part, the first angle and the second angle are constant. 
     In addition, an angle change is possible by moving the displacement element relative to the vehicle seat lower part. 
     Depending on the size of the first angle and the second angle, it is possible to adjust the spring stiffness of the first spring element and optionally of the second spring element. The spring stiffness is in particular an adjustment option for the vertical direction and for the rolling direction for the suspension movement. By setting the first angle and the second angle, it is possible to set the spring stiffness with regard to the vertical direction and the rolling direction or the rolling spring direction and vertical spring device. 
     In addition, the spring stiffness can be influenced by the displacement of the displacement element, in particular during a suspension movement. 
     According to a particularly preferred embodiment, it is provided that a displacement of the displacement element is possible in the event of a rolling movement of the vehicle seat. 
     The displacement of the displacement element relative to the vehicle seat lower part is particularly preferred, depending on the strength of the rolling movement, i.e. on the angle of rotation about the first axis of rotation. 
     It is particularly preferred that the first scissor arm and the second scissor arm intersect in a first region, viewed in the vehicle seat longitudinal direction, wherein provision is made that no structural connection is provided between the first scissor arm and the second scissor arm, with the exception of the spring element support. This means in particular that when the vehicle seat upper part moves with respect to the vehicle seat lower part, the first region, which represents the intersection region of the first scissor arm with the second scissor arm, must follow the movement of the vehicle seat. In particular, this means that there is no common axis of rotation between the first scissor arm and the second scissor arm. 
     According to an alternative embodiment, a structural connection is provided between the first scissor arm and the second scissor arm, so that the scissor arrangement is a scissor frame in the conventional sense, i.e. the scissor arms are rotatably connected to one another about a common axis of rotation. In this case, the spring element support is preferably fastened directly to the common axis of rotation. 
     It can be provided that the first scissor arm and the second scissor arm are force-connected, for example by a frictional force, if the scissor arms are in contact with one another. 
     The above-described forced guidance or forced movement of the spring element support due to the movement of the vehicle seat upper part relative to the vehicle seat lower part produces a spring force of the first spring element and the second spring element, so that cushioning of the vehicle seat is caused by the suspension unit. 
     Generally speaking, when the vehicle seat upper part moves relative to the vehicle seat lower part in a vertical direction, i.e. in the vehicle seat height direction, due to an external force acting on the vehicle seat, the rotatable arrangement of the spring element support on the first scissor arm or the second scissor arm causes a corresponding movement of the spring element support. This means that in the event of a vertical deflection, i.e. a deflection in the vehicle seat height direction, the spring element support experiences a linear shift corresponding to the vehicle seat upper part in the vehicle seat height direction. In the event of a rolling movement of the vehicle seat, i.e. in the event of a rotation of the vehicle seat upper part relative to the vehicle seat lower part about the first axis of rotation, the spring element support is also subjected to such a rolling movement. 
     According to a preferred embodiment, it is provided that a sensor is arranged on the vehicle seat, by means of which a rolling deflection of the vehicle seat can be detected. The sensor is preferably designed as an angle sensor. The sensor is further preferably arranged on the vehicle seat upper part or the vehicle seat lower part and is particularly preferably designed to determine a deviation angle to the surface of the earth, i.e. the sensor functions like a kind of spirit level. 
     The first spring element is deformed by the rolling movement of the spring element support, so that a spring force is produced which counteracts the rolling movement. 
     According to a particularly preferred embodiment, it is provided that the suspension unit comprises a second spring element, wherein the second spring element is connected on the one hand to the displacement element and on the other hand to the spring element support, and wherein the second spring element is preferably arranged at a third angle to the vehicle seat width direction and arranged at a fourth angle to the vehicle seat height direction. 
     The second spring element is particularly preferably arranged in such a way that, with respect to a plane formed from the vehicle seat longitudinal direction and the vehicle seat height direction, the first spring element is arranged on a first side of the plane and the second spring element on the second side of the plane. 
     It is also possible that the first angle corresponds to the third angle and the second angle corresponds to the fourth angle, so that the first spring element and the second spring element are arranged symmetrically to one another with respect to the plane formed from the vehicle seat longitudinal direction and the vehicle seat height direction. 
     However, it is also possible that the first angle has a different value from the third angle and that the second angle has a different value from the fourth angle. 
     It is pointed out that “symmetrical” is to be understood to mean in the neutral state, i.e. no external force is acting on the vehicle seat. With a suspension movement of the vehicle seat, the arrangement of the spring elements in relation to one another changes since, in particular during a rolling movement, one spring element is compressed and the other spring element is correspondingly decompressed, i.e. one spring element is compressed and the other spring element is stretch in its length. 
     According to a particularly preferred embodiment, it is provided that the first angle and the second angle can each assume a value from a range of 0 to 90°]. 
     According to a further preferred embodiment, it is provided that the third angle and the fourth angle can each assume a value from a range of 0 to 90°]. 
     It is particularly preferably provided that the first angle, the second angle, the third angle and the fourth angle cannot assume the angle value 90°, i.e. the angles can each assume a value in the range of 0 to 90°[. This means that, when seen in particular in the vehicle seat height direction, the spring elements do not correspond to a vertical spring. 
     According to a further preferred embodiment, it is provided that the first axis of rotation is arranged parallel to the vehicle seat longitudinal direction, and preferably the second axis of rotation and the third axis of rotation are arranged extending in the vehicle seat width direction and the second and the third axis of rotation are arranged parallel to one another. 
     In particular, the arrangement of the second axis of rotation and the third axis of rotation can prevent the scissor arrangement with the spring element support from tilting, in particular when the vehicle seat upper part moves relative to the vehicle seat lower part. 
     According to a particularly preferred embodiment, it is provided that the first axis of rotation is defined by a shaft which is rotatably connected to the vehicle seat lower part. The shaft preferably has a first end and a second end, wherein the first end and the second end each are rotatably connected to the vehicle seat lower part. Instead of a shaft, a rod element is also conceivable, wherein it is possible for the shaft or the rod element to be cylindrical or angular. 
     According to a further preferred embodiment, it is provided that the first scissor arm is connected to the vehicle seat upper part by means of a first floating bearing and to the shaft by means of a second floating bearing, and the second scissor arm is connected to the vehicle seat upper part by means of a third floating bearing and to the shaft by means of a fourth floating bearing. Such a configuration also allows a pitching suspension movement of the vehicle seat by means of the suspension unit. 
     According to the design of the first scissor arm and the second scissor arm by means of four floating bearings for connection to the vehicle seat upper part and the vehicle seat lower part, it is achieved that the pitching movement of the vehicle seat can be easily followed when the vehicle seat is pitched and when the vehicle seat upper part follows the vehicle seat lower part accordingly. Because four floating bearings are provided, the suspension unit is mechanically indeterminate, i.e. degrees of freedom still exist which cannot be adequately determined. In order to further minimise these degrees of freedom, a first connecting element and a second connecting element are provided, which minimise the degrees of freedom of the four floating bearings through the corresponding arrangement with the first scissor arm and the second scissor arm and the vehicle seat upper part and the vehicle seat lower part. Particularly preferably, a first connecting element is provided which connects the first scissor arm to a fixed bearing which is arranged on the shaft, and wherein a second connecting element is provided which has a first connecting element part and a second connecting element part, wherein the first connecting element part is rotatably connected to the second scissor arm and the second connecting element part, and wherein the second connecting element part is rotatably connected to the first connecting element part, the first scissor arm and the vehicle seat upper part. 
     Alternatively, the scissor arrangement can be such that the first scissor arm is connected to a support part by means of a fixed bearing and to the vehicle seat upper part by means of a first floating bearing and the second scissor arm is connected to the vehicle seat upper part by means of a further fixed bearing and to the support part by means of a fourth floating bearing. The support part is preferably mounted rotatably with respect to the vehicle seat lower part. 
     According to a further preferred embodiment, it is provided that the second floating bearing and the fourth floating bearing are each designed as a shifting element so that the first scissor arm and the second scissor arm are in each case shiftable relative to the shaft. A shift with respect to the shaft means that a shift of the first scissor arm and of the second scissor arm is provided in the vehicle seat longitudinal direction. The shifting element can be designed as a sliding element or as a rolling element, so that a smooth shift of the first scissor arm and the second scissor arm relative to the shaft can be ensured. 
     According to a further preferred embodiment, it is provided that, when viewed in the longitudinal direction of the vehicle seat, the second floating bearing is arranged in front of the third floating bearing and the first floating bearing is arranged in front of the fourth floating bearing. 
     By a rolling movement of the vehicle seat and a corresponding tracking of the spring support element, which is in connection with the first or the second spring element, which can in particular be designed to be elastically deformable, the spring support element causes deformation of the spring elements, whereby a spring force or a restoring force of the spring elements is generated. 
     According to a further preferred embodiment, a locking unit is provided so that a movement of the suspension unit can be locked about the first axis of rotation, so that a rotational movement about the first axis of rotation can preferably be blocked. This is advantageous if the vehicle is moving on a level surface, such as a street, where usually little or no rolling movements occur. 
     Furthermore, according to a particularly preferred embodiment, it is provided that the displacement element is substantially flat and is translationally displaceable with respect to the vehicle seat lower part. In particular, the displacement element is translationally displaceable in the vehicle seat width direction. 
     “Flat” here means in particular that at least one flat portion is provided, wherein the extent of the flat portion is provided in the vehicle seat width direction and in the vehicle seat longitudinal direction. The extent in the vehicle seat height direction is negligible compared to the extent in the vehicle seat longitudinal direction and in the vehicle seat width direction. 
     According to a further preferred embodiment, it is provided that the displacement element can be displaced relative to the vehicle seat lower part by means of an actuator, wherein the actuator preferably is connected on the one hand to the displacement element and on the other hand to the vehicle seat lower part. 
     More preferably, the actuator moves the displacement element as a function of the rolling deflection of the vehicle seat, i.e. as a function of the value of the sensor. In this case, the dependency is preferably such that if there is a greater rolling deflection, a greater displacement of the displacement element is carried out by means of the actuator. As already described, the force component of the spring elements can be influenced by the displacement of the displacement element. 
     According to a preferred embodiment, the actuator is a mechanical actuator, an electrical actuator, a pneumatic actuator or a hydraulic actuator. According to a further preferred embodiment, the actuator is one selected from the group comprising a rack with an associated pinion, an electric cylinder, a pneumatic cylinder and a hydraulic cylinder. 
     A method for cushioning the rolling movements of a vehicle seat is also provided, wherein the method comprises the steps:
         a) Determining a rolling deflection of the vehicle or of the vehicle seat lower part by means of a sensor, in particular an angle sensor;   b) Determining a displacement path of the displacement element;   c) Controlling the actuator so that the displacement element is displaced by the displacement distance by means of an actuator movement.       

     The displacement distance depends on the specific rolling deflection of the vehicle seat. The greater the rolling deflection of the vehicle, the greater the displacement distance. 
     Furthermore, the displacement of the displacement element is a function of the direction of roll of the vehicle seat. This is shown below in accordance with the drawings. With a clockwise rolling movement, the vehicle seat upper part and the vehicle seat lower part move towards one another in the left region and away from one another in the right part. This means that the spring elements are displaced in such a way that the vertical force components acting on the vehicle seat upper part of the two spring elements are the same. This prevents the upper part of the vehicle seat from tilting. The displacement of the displacement element is such that the displacement element is pushed from the neutral position in the direction to the left, so that the force component of the left spring element can be reduced. The stronger the rolling movement, the greater the displacement in order to be able to cushion the stronger rolling movement. 
     Further advantageous embodiments result from the dependent claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Additional objects, advantages and expedient uses of the present invention can be found in the following description in conjunction with the drawings. In the drawings: 
         FIG. 1  is a perspective view of a vehicle seat according to a preferred embodiment; 
         FIG. 2A  is a front view of a vehicle seat in a neutral position; 
         FIG. 2B  shows the vehicle seat according to  FIG. 2A  in a rolling position without displacement of the displacement element; 
         FIG. 2C  shows the vehicle seat according to  FIG. 2A  in a rolling position with displacement of the displacement element; 
         FIG. 2D  is a comparison of  FIGS. 2B and 2C ; 
         FIG. 3  shows a vehicle seat according to one embodiment with different angles of attack of the spring elements; 
         FIG. 4A  is a side view of a vehicle seat in the neutral position; 
         FIG. 4B  shows a section along BB in  FIG. 4A ; 
         FIG. 5A  is a side view of a vehicle seat in the rolling position; 
         FIG. 5B  shows a section along DD in  FIG. 5A ; 
         FIG. 6A  shows a scissor arrangement according to a first embodiment; 
         FIG. 6B  shows a scissor arrangement according to a second embodiment; 
         FIG. 7A  is a schematic representation of the vehicle seat according to  FIG. 1A  in the neutral position; 
         FIG. 7B  is a schematic representation of the vehicle seat according to  FIG. 1A  in the downwardly displaced position; 
         FIG. 8A  is a first perspective view of a spring support element; 
         FIG. 8B  is a second perspective view of a spring support element. 
     
    
    
     DETAILED DESCRIPTION 
     In the drawings, the same components are denoted by the same reference numerals, wherein it is possible for the reference numerals to be omitted in some drawings for greater clarity. 
       FIG. 1  shows a vehicle seat  1  or a vehicle seat substructure  1 ′, wherein the vehicle seat  1  has a vehicle seat upper part  3  and a vehicle seat lower part  4 , which are connected to one another by means of a suspension unit  2  in such a way that the vehicle seat upper part and the vehicle seat lower part can be moved and cushioned relative to one another. It can also be seen that the suspension unit  2  is rotatably connected about a first axis of rotation  10  to the vehicle seat lower part  4 . 
     The suspension unit  2  comprises a scissor arrangement  5  having a first scissor arm  6  and a second scissor arm  7 , a third scissor arm  8  and a fourth scissor arm  9 , wherein the suspension unit further comprises a spring element support  11  and a first spring element  12  and a second spring element  13 . As can be seen, the spring element support is rotatably connected about a second axis of rotation to the first scissor arm and rotatably connected about a third axis of rotation  15  to the second scissor arm  7 , wherein the first spring element  12  is connected to the displacement element  100  on the one hand and to the spring element support  11  on the other hand, wherein the first spring element  12  is further preferably arranged at a first angle  16  to a vehicle seat width direction B and at a second angle  17  to a vehicle seat height direction H. 
     The more detailed arrangement of the spring elements  12 ,  13  and the more detailed configuration of the scissor arrangement  5  and the displacement element  100  are described further in the following drawings. 
     The first air spring  12  and the second air spring  13  are designed as an elastically deformable air spring in  FIG. 1 , wherein it is also conceivable that the first spring element  12  and the second spring element  13  can be designed as a mechanical spring. 
     It is also conceivable that the first spring element  12  is designed as an air spring and the second spring element  13  as a mechanical spring, or vice versa. 
     Furthermore, the scissor arrangement  5  has a first connecting element  25  and a second connecting element  26 , wherein the second connecting element  25  has a first connecting element part  27  and a second connecting element part  28 , wherein the first connecting element  25  is rotatably connected to the first scissor arm  6  and on the other hand is connected to a first fixed bearing  29 , wherein the first fixed bearing  29  is connected to a shaft  20  or to a support part  40 . 
     Furthermore, the first connecting element part  27  is rotatably connected to the second scissor arm  7  and rotatably connected to the second connecting element part  28 , wherein the second connecting element part  28  is further rotatably connected to the first scissor arm  7  and connected to the vehicle seat upper part  3  by means of a fixed bearing  30 . 
     In  FIGS. 2A, 2B, 2C and 2D , the vehicle seat according to  FIG. 1  is shown in a front view, wherein in  FIG. 2A  the vehicle seat  1  is shown in a neutral position N, in  FIG. 2B  it is shown in a rolling position W without displacement of the displacement element  100 , and in  FIG. 2C  in a rolling position with displacement of the displacement element  100 , and in  FIG. 2D  a comparison of  FIGS. 2B and 2C . 
     With regard to  FIG. 2A , which shows the vehicle seat  1  in the neutral position N, it can be seen that the first spring element  12  is arranged at a first angle  16  and the second spring element  13  at a third angle  18  to the vehicle seat width direction B. According to the invention, it is provided that the first spring element  12  and the second spring element  13  are connected to the spring element support  11  on the one hand and to the displacement element  100  on the other hand. In the case of a suspension movement in the vehicle seat height direction H, i.e. in the vertical direction of the vehicle seat  1 , it is provided that the position of the first spring element  12  or the second spring element  13  is changed at this point through the connection to the displacement part  100 , even without displacement of the displacement part  100 , but when moving in the vehicle seat height direction in the direction H, the spring element support  11  naturally also moves upwards or downwards in the vehicle seat height direction H. This means that the connection point between the spring elements  12 ,  13  to the spring element support  11  also moves upwards or downwards in the vehicle seat height direction H. This means that the first angle  16  and the third angle  18  are not constant during a suspension movement in the vehicle seat height direction H. 
     The change in angles  16 ,  17 ,  18 ,  19  can be seen from a comparison of  FIGS. 2B and 2C . A superposition of  FIGS. 2B and 2C  can be seen in  FIG. 2D . The change in angle is again shown schematically. 
     The fact that, due to the rolling movement of the vehicle seat  1 , an actuator  101  ensures that the displacement element  100  is displaced with respect to the vehicle seat lower part  4 , a further improvement in the cushioning of the rolling movement of the vehicle seat  1  can be achieved. This can be seen in particular in  FIG. 2D . 
     The vehicle seat  1  according to  FIG. 2A  can also be seen in  FIG. 3 , wherein the angles of attack, i.e. the first angle  16  and the third angle  18 , are different from one another. This means that the first angle  16  has a different angle from the third angle  18 . 
     In general, the description with regard to the first angle  16  and the third angle  18  also applies to the second angle  17  and the fourth angle  19 . 
     However, it can also be provided that in a neutral position N of the vehicle seat  1 , the first angle  16  corresponds to the third angle  18  and the second angle  17  corresponds to the fourth angle  19 . 
     The configuration with different angles for the respective spring element  12 ,  13  makes it possible to adjust the spring stiffness of the spring elements  12 ,  13 . 
       FIG. 4A  is a side view of the vehicle seat  1  in the neutral position N, and  FIG. 4B  is a section along the line B-B, as shown in  FIG. 4A . 
       FIG. 5A  is a side view of the vehicle seat  1  in the rolling position W, and  FIG. 5B  is a section along the line DD, as shown in  FIG. 5A . 
     Particularly in  FIGS. 4B and 5B , attention is directed to the displacement element  100 , which is shown in more detail here. 
     As can be seen, the main extensions of the displacement element  100 , which is substantially flat, are the vehicle seat width direction B and the vehicle seat longitudinal direction L, in the neutral position N of the vehicle seat  1 . It should be noted that the main extensions rotate accordingly about the first axis of rotation  10  during a rolling movement, so that the extensions of the displacement element  100  are each arranged at an angle to the vehicle seat width direction B and the vehicle seat longitudinal direction L. 
     As can be seen, the displacement element  100  has a first flat region  102 , a second flat region  103 , and a third flat region  104 , wherein the second flat region  103  connects the first flat region  102  and the third flat region  104  to one another. 
     The first flat region  102  is connected to the first spring element  12  by means of a lower adapter element  39  and the third flat region  104  is connected to the second spring element by means of a further lower adapter element  39 . The respective lower adapter element  39  is firmly connected to the displacement element  100 . 
     Further preferably, as seen in the neutral position N of the vehicle seat, the second flat region  103  is arranged in the vehicle seat height direction H below the first flat region  102  and the third flat region  104 . This serves to create sufficient space under the first axis of rotation  10  for the vehicle seat  1  during the rolling movement. 
     As can be seen in particular from  FIG. 5B  in comparison with  FIG. 4B , the displacement element  100  was displaced relative to the vehicle seat lower part  4  due to the rolling movement of the vehicle seat  1 . 
     A first embodiment of the scissor arrangement  5  can be seen in  FIG. 6A  and a second embodiment of the scissor arrangement  5  can be seen in  FIG. 6B . 
     The embodiment of the scissor arrangement  5  according to  FIG. 6A  will be described first. 
     The scissor arrangement  5  comprises a first scissor arm  6 , a second scissor arm  7 , a third scissor arm  8  and a fourth scissor arm  9 . 
     The designs of the third scissor arm  8  and the fourth scissor arm  9  apply correspondingly to the associated first scissor arm  5  and the associated second scissor arm  7 . This is particularly true since the third scissor arm  8  runs identically to the first scissor arm  6  and the fourth scissor arm  9  runs identically to the second scissor arm  7 . 
     As can also be seen, the spring element support  11  is provided, which is rotatably connected about a second axis of rotation  14  to the first scissor arm  6  and rotatably connected about a third axis of rotation  15  to the second scissor arm  7 . 
     Furthermore, the first scissor arm  6  is connected to the vehicle seat upper part  3  by means of a first floating bearing  21  and to a shaft  20  by means of a second floating bearing  22 , and the second scissor arm  7  is connected to the vehicle seat upper part  3  by means of a third floating bearing  23  and to the shaft  20  by means of a fourth floating bearing  24 , wherein a first connecting element  25  connects the first scissor arm  6  to a first fixed bearing  29  which is arranged on the shaft  20 , and wherein a second connecting element  26  is provided which has a first connecting element part  27  and a second connecting element part  28 , wherein the first connecting element part  27  is rotatably connected to the second scissor arm  7  and the second connecting element part  28 , and wherein the second connecting element part  28  is rotatably connected to the first connecting element part  27 , the first scissor arm  6  and the vehicle seat upper part  3 . The second connecting element part  28  is rotatably connected in particular to a second fixed bearing  30 . The second fixed bearing is arranged on the vehicle seat upper part  3 . 
     The first floating bearing  21  and the second floating bearing  23  are each designed as running rollers  36 , which are rotatably connected to the respective scissor arm  6 ,  7 ,  8 ,  9  and are mounted in a rolling manner in a running rail  37 , wherein the running rail  37  is arranged on the vehicle seat upper part  3 . 
     The second floating bearing  22  and the fourth floating bearing  24  are designed in such a way that a first shifting element  31  and a second shifting element  32  are provided, wherein the first scissor arm  6  is rotatably connected to the first shifting element and the second scissor arm  7  is rotatably arranged on the second shifting element  32 . 
     The shifting elements  31 ,  32  can be shifted in such a way that they can be shifted with respect to the shaft  20  in the direction of the first axis of rotation  10 . 
     The first shifting element  31  and the second shifting element  32  are shifted in particular when the vehicle seat  1  moves vertically. 
     Because the scissor arms  6 ,  7 ,  8 ,  9  are each connected to the vehicle seat lower part or to the vehicle seat upper part  3  by means of a floating bearing, it is necessary to limit the degrees of freedom with regard to the movement of the scissor arrangement  5 . This is done by means of the first connecting element  25  and the second connecting element  26 . 
     Furthermore, the spring element support  11  has an adapter plate  38 , by means of which the respective spring element  12 ,  13  (not shown here) can be connected to the spring element support  11 . 
     The second embodiment, which is shown in  FIG. 6B , is identical in terms of its functional principle to the embodiment of  FIG. 6A , although the configuration differs. 
     The embodiment of  FIG. 6B  also includes a first scissor arm  6 , a second scissor arm  7 , a third scissor arm  8 , and a fourth scissor arm  9 , wherein the first scissor arm  6  and the third scissor arm  8  as well as the second scissor arm  7  and the fourth scissor arm  9  each run identically. Likewise, the respective scissor arms  6 ,  7 ,  8 ,  9  are guided in the guide rail  37  of the vehicle seat upper part  3  by means of a floating bearing  21 ,  23  which is designed as a running roller  36 . 
     This embodiment also has the first connecting element  25  and the second connecting element  26  in the same arrangement and function as described in  FIG. 6A . 
     The arrangement of the floating bearings  22 ,  24  with respect to the vehicle seat lower part  4  is different here. In particular, a support part  40  is shown which is rotatably connected to the vehicle seat lower part  4  about the first axis of rotation  10 . A shaft  20  is provided at the front and the rear end of the support part in the vehicle seat longitudinal direction L, the support part  40  also having running rails  37  in which the floating bearings  22 ,  24  can roll by means of running rollers  36  with respect to the support part  40 . 
     The first fixed bearing  29 , by means of which the first scissor arm  6  is connected by means of the first connecting element  25 , is also arranged on the support part  40 . 
     A lower adapter plate  39  is also shown schematically in  FIG. 6B , by means of which the spring element  12 ,  13  can be connected to the vehicle seat lower part  4 . As can be seen, the lower adapter plate  39  has an inclined portion, by means of which the angle of the corresponding spring element  12 ,  13  can be adjusted. 
     The same also applies to the upper adapter plate  38 , which has an angle with respect to the vehicle seat width direction B, wherein the inclination of the upper adapter plate  38  and of the lower adapter plate  39  are parallel to one another. 
     In  FIGS. 7A and 7B , the kinematics of the moving parts of the vehicle seat  1  is shown again schematically. 
     In  FIG. 7A , the vehicle seat is shown in the neutral position N and in  FIG. 7B  in the downward position U. 
     The movement of the moving parts, which are denoted by the corresponding reference numerals, can be seen by comparing  FIGS. 7A and 7B . 
     Furthermore,  FIGS. 8A and 8B  show the spring element support  11  in a first perspective and in a second perspective representation. 
     The spring element support  11  has a first spring element support holder  45  and a second spring element support holder  46 , which are connected to one another by means of a connecting part  47 . The respective spring element support holder  45 ,  46  has a first connection point  42  and a second connection point  43 , by means of which the spring element support can be connected, in particular rotatably, to the first scissor arm  6  and the second scissor arm  7 , or to the third scissor arm  8  and the fourth scissor arm  9 . 
     Furthermore, both the first spring element holder  45  and the second spring element holder  46  have an adapter plate holder  44 , by means of which the upper adapter plate  38  can be connected to the spring element support  11 . 
     All features disclosed in the application documents are claimed as being essential to the invention, provided that they are, individually or in combination, novel over the prior art. 
     LIST OF REFERENCE SIGNS 
       1  Vehicle seat 
       2  Suspension unit 
       3  Vehicle seat upper part 
       4  Vehicle seat lower part 
       5  Scissor arrangement 
       6  First scissor arm 
       7  Second scissor arm 
       8  Third scissor arm 
       9  Fourth scissor arm 
       10  First axis of rotation 
       11  Spring element support 
       12  First spring element 
       13  Second spring element 
       14  Second axis of rotation 
       15  Third axis of rotation 
       16  First angle 
       17  Second angle 
       18  Third angle 
       19  Fourth angle 
       20  Shaft 
       21  First floating bearing 
       22  Second floating bearing 
       23  Third floating bearing 
       24  Fourth floating bearing 
       25  First connecting element 
       26  Second connecting element 
       27  First connecting element part 
       28  Second connecting element part 
       29  First fixed bearing 
       30  Second fixed bearing 
       31  First shifting element 
       32  Second shifting element 
       33  Damper element 
       34  First end of the shaft 
       35  Second end of the shaft 
       36  Running roller 
       37  Running rail 
       38  Adapter plate 
       39  Lower adapter plate 
       40  Support part 
       41  Locking element 
       42  First connection point 
       43  Second connection point 
       44  Adapter plate holder 
       45  First spring element support holder 
       46  Second spring element support holder 
       47  Connecting part 
       48  Damper element holder 
       100  Displacement element 
       101  Actuator 
       102  First flat region 
       103  Second flat region 
       104  Third flat region 
     N Neutral position 
     W Rolling position 
     L Vehicle seat longitudinal direction 
     B Vehicle seat width direction 
     H Vehicle seat height direction