Abstract:
The invention relates to a device for damping an upper suspension part in at least one spatial direction (X, Y, Z) with respect to a lower suspension part movable relative thereto, wherein a spring apparatus which acts between the upper suspension part and the lower suspension part is provided for damping, wherein an actuating element is provided by way of which a force can be introduced into the device bidirectionally in the operating direction of the spring apparatus, wherein the actuating element is actuable via a control apparatus.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of German Application No. 10 2014 001 890.3 filed Feb. 14, 2014, the contents of which are incorporated herein by reference. 
     FIELD 
     The invention relates to a device for damping an upper suspension part in at least one spatial direction with respect to a lower suspension part movable relative thereto. 
     BACKGROUND 
     Devices of this type are often used to damp vehicle seats during operation of a vehicle. In this respect, the upper suspension part is connected to the seat surface of the vehicle seat, whilst the lower suspension part is arranged fixed in place on the vehicle or the body thereof, respectively. 
     However, in devices of this type for damping an upper suspension part with respect to a lower suspension part, it is problematic that during the operation of the device, in particular in a vehicle seat, temporary deviations from a pre-set distance between the lower and upper suspension face occur as a result of forces introduced into the device. 
     SUMMARY 
     An object of the invention is therefore to further develop a device of the aforementioned type in such a way that deviations of this type during the operation of the device are minimised. 
     This object is achieved by a device having all of the features of claim  1 . Advantageous configurations of the invention may be found in dependent claims  2  to  9 . This object is further achieved by a seat having all of the features of claim  10  and a vehicle having all of the features of claim  11 . 
     The device according to the invention for damping an upper suspension part in at least one spatial direction with respect to a lower suspension part movable relative thereto, in which a spring apparatus which acts between the upper suspension part and the lower suspension part is provided for damping, therefore comprises an actuating element by way of which a force can be introduced into the device bidirectionally in the operating direction of the spring apparatus, this actuating element being actuable via a control apparatus. In a vehicle seat, a force of this type which can be introduced bidirectionally will generally be introducible in a positive and negative Z direction or vehicle vertical direction. However, it is also conceivable, in particular if this device is used in a vehicle seat, alternatively or additionally to introduce bidirectional forces both in the positive and negative X or longitudinal direction, respectively, and in the positive and negative Y or width direction, respectively. 
     As a result of the configuration according to the invention of the device, it is now possible to control the device actively, bidirectionally in the operating direction of the spring apparatus, via the actuating element, in such a way that the actuating element on the one hand brings about levelling in the event of temporary deviations in the distance between the lower and upper suspension face and on the other hand brings about an active engagement in isolating oscillations. 
     According to a first advantageous configuration of the invention, for this purpose the actuating element also comprises a drive, preferably configured as a rotary field magnet, and a coupling rod, drivable by the drive and preferably in the form of a recirculating ball screw. As a result of the drive and the coupling rod coupled thereto, it is now possible actively to counter suspension movements which occur during the operation of the device. In particular the configuration of the drive as a rotary field magnet, also known as a torque motor, is particularly advantageous, since a rotary field magnet of this type can also produce a standstill torque in long-term operation. 
     In this respect, it has been found to be advantageous to select the thread pitch of the recirculating ball screw in such a way that the drive of the lead screw can be produced by both the drive in the form of a rotary field magnet and the spring apparatus. In this case, there is never any self-locking by way of the pitch of the recirculating ball screw. 
     In accordance with a further inventive idea, the spring apparatus comprises a spring, which is arranged between the upper suspension part and the lower suspension part which is preferably in the form of an air spring, and a scissor-type support apparatus, which connects the upper suspension part to the lower suspension part such that they are movable relative to one another. A configuration of this type of the device according to the invention is particularly suitable for an application as suspension for a seat, in particular for a vehicle seat. The device according to the invention can thus be arranged between the seat surface and the vehicle body in a simple and compact manner, in such a way that it does not require any additional space. 
     It has been found to be advantageous for the scissor-type support apparatus to comprise a first scissors, consisting of a first inner link and a first outer link, and a second scissors, consisting of a second inner link and a second outer link, which are preferably interconnected via at least one floating bearing connection. As a result of this configuration of the invention, it is possible to configure the device particularly stably in the operating direction of the spring, in such a way that even tilting movements of the upper suspension face with respect to the lower suspension face are effectively prevented as a result. 
     In this respect, the drive may be fixedly arranged on the upper suspension part or lower suspension part, respectively, and the coupling rod on a floating bearing connection. However, it is also conceivable for the coupling rod to be fixedly arranged on the upper suspension part or lower suspension part, respectively while the drive acts on a floating bearing connection. 
     In accordance with a particularly advantageous inventive idea, the coupling rod is formed in a spring-loaded manner with at least one spring element. As a result of this configuration of the invention, when a force is introduced into the device according to the invention, the at least one spring element of the coupling rod is initially biased and the drive is only subsequently activated. As a result of this coupling of the drive to a coupling rod which is configured with at least one spring, permanent entrainment of the drive in rotation can be prevented, in particular in the high-frequency or short-stroke operating range, respectively of the device according to the invention. As a result of the superposition of different provided spring characteristics—on the one hand the spring of the spring apparatus and on the other hand this at least one spring element of the coupling rod—a wide spectrum for the introduction frequencies to be isolated is achieved. In this respect, the usable field of forces consists of the spring rate of the spring means and the spring rate of the at least one spring element, serving as a decoupling spring, of the coupling rod as well as of the force spectrum of the drive. In this respect, the spring of the spring apparatus, which in the present case merely acts as a passive component, is used as a basis for receiving the base load which acts on the device according to the invention as a mass. In this respect, when the device according to the invention is first used, a load of a predetermined force is raised to a predetermined distance level between the lower and upper suspension faces. The available force of the drive can now be produced in both directions of the operating direction of the spring apparatus by way of the drive in the form of a rotary field magnet. During the operation of the device according to the invention, this force of the drive is used to correct temporary distance deviations between the lower and upper suspension faces, in such a way that as a result of the device according to the invention the predetermined distance between the lower and upper suspension face is permanently aimed for and merely minimal deviation therefrom occurs. 
     In this respect, it has been found to be advantageous for at least one movement sensor to be provided, by means of which the movements of the upper suspension part with respect to the lower suspension part in the at least one spatial direction can be detected. The data detected by the movement sensor can preferably be passed on to the control apparatus. As a result of this movement sensor, which may be formed as a path sensor or angle sensor, the dynamics, in other words the movement of the lower suspension face with respect to the upper suspension face, are detected and passed on to the control apparatus. In this respect, the measurement range corresponds to the total stroke of the spring apparatus. During active control of the device according to the invention, the entire force spectrum of the drive or of the rotary field magnet, respectively is made use of so as to influence introductions of force into the device according to the invention. 
     The device according to the invention can thus both act together with the introduction of force, in other words the supporting force for the upper suspension side to carry a mass is reduced, and counter the introduction of force, in which case the force counter to the introduction of force is increased. 
     The high-frequency control which is required for influencing the oscillations is provided in this respect by way of the changes in the supplied current or in the direction of rotation of the drive or the rotary field magnet, respectively. In this respect, the type and intensity of the control is stored in a control algorithm of the control apparatus. The type and intensity of the force introduction are detected by the device according to the invention by way of the acceleration reader, which is fixed to the lower suspension part, and the movement sensor, which evaluates the distance or the deviation thereof, respectively between the upper suspension part and the lower suspension part. 
     In accordance with a further inventive idea, a shock absorber is provided for damping oscillations of the spring apparatus. 
     The invention also further relates to a seat, in particular a vehicle seat, comprising an above-described device according to the invention, and also to a vehicle comprising at least one seat of this type or respectively comprising at least one above-described device according to the invention. 
     Further aims, advantages, features and possible applications of the present invention may be seen from the following description of embodiments by way of the drawings. In this respect, all of the features which are described and/or shown in the drawings, in isolation or in any reasonable combination, form the subject matter of the present invention, irrespective of how they are compiled in the claims or the dependencies thereof. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an embodiment of a device according to the invention, 
         FIG. 2  is a different perspective view of the device according to the invention in accordance with  FIG. 1 , 
         FIG. 3  is a front view of the device in accordance with  FIGS. 1 and 2 , 
         FIG. 4  is a section along line A-A from  FIG. 3  of the device according to the invention from  FIG. 3 , 
         FIG. 5  is a side view of the device according to the invention in accordance with  FIGS. 1 to 4 , 
         FIGS. 6 a  to 6 c    show the device according to the invention of  FIGS. 1 to 5  in different loading states, 
         FIG. 7  shows an embodiment of an actuating element of a device according to the invention, 
         FIG. 8  shows the stroke of the coupling rod in accordance with  FIG. 7  in relation to the revolutions thereof, 
         FIG. 9  shows a further embodiment of an actuating element of a device according to the invention, 
         FIG. 10  is a section along line D-D through the actuating element in accordance with  FIG. 9 , 
         FIG. 11  is a force-deflection graph for a device according to the invention, and 
         FIG. 12  is a further force-deflection graph for another device according to the invention. 
     
    
    
       FIGS. 1 to 6   c  are various views of an embodiment of a device according to the invention, which is used in a vehicle seat for damping oscillations during the operation of the vehicle. 
     DETAILED DESCRIPTION 
     In this respect, the device comprises an upper suspension face  1  and a lower suspension face  2 , between which a spring means  3  is arranged. In the present case, the spring means  3  consists of a scissor-type support apparatus  6  and of a spring  5  in the form of an air spring, by means of which movements in a vertical direction Z can be damped. In this respect the scissor-type support apparatus  6  consists of a first scissors  10  and a second scissors  13 . The first scissors  10  consists of a first inner link  7  and a first outer link  8 , these being interconnected so as to be pivotable with respect to one another approximately in the centres thereof. The second scissors  13  consists of a second inner link  11  and a second outer link  12 , which are likewise interconnected so as to be pivotable with respect to one another approximately in the centres thereof. The lower ends of the first inner link  7  and the second inner link  11  are arranged on a floating bearing transverse connection  24 , which is mounted in fixed bearings  25  arranged fixedly on the lower suspension face  2 . At the upper ends thereof, the first inner link  7  and the second inner link  11  are interconnected by means of an additional floating bearing transverse connection  31 , at the ends of which there are rollers  32  which are guided in guide rails  26  and  28  arranged on the upper vehicle face. 
     Analogously, at the upper ends thereof, the first outer link  8  and the second outer link  12  are mounted in fixed bearings  25 ′ arranged on the upper suspension face by means of a floating bearing transverse connection  24 ′. At the lower ends thereof, the first outer link  8  and the second outer link  12  are interconnected via a further floating bearing transverse connection  30 , rollers  33 , which are guided in guide rails  27  and  29  arranged on the lower suspension face  2 , being arranged at the ends of the floating bearing transverse connection  30 . 
     By means of the entire spring apparatus  6 , in this respect the distance between the upper suspension face  1  and the lower suspension face  2  can be varied by force input, for example if a force is applied to the device arranged in a vehicle seat by a person sitting down on the vehicle seat. 
     Since during operation of the device in a vehicle seat oscillations due to irregularities in the road surface on which the vehicle is moving or due to displacement of the weight of the person sitting on the seat vary the force introduced to the device according to the invention during operation of the vehicle, an actuating element  4 , by means of which the externally introduced force input into the device can be countered, is provided for compensating this force input. 
     In the present embodiment, the actuating element  4  consists of a drive  23  in the form of a rotary field magnet  14 , by means of which a coupling rod  16  in the form of a recirculating ball screw  15  can be moved back and forth. For this purpose, the recirculating ball screw  15  comprises, on the circumference thereof, a screw having a screw pitch of approximately 45°. The drive  23  in the form of a rotary field magnet  14  is arranged fixedly on the lower suspension face  2 , whilst the coupling rod  16  is arranged on the floating bearing transverse connection  30  via a fixing element  22 . 
     To make it possible to detect movements and accelerations of the upper suspension face  1  with respect to the lower suspension face  2 , a movement sensor  19 , in this case in the form of an angle sensor, and an acceleration sensor  20  are provided. By means of these sensors  19  and  20 , the intensity of the introduction of force and the distance or deviations, respectively from a predetermined distance between the upper suspension part  1  and the lower suspension part  2  can be established. In this respect, the data detected by the sensors  19  and  20  can be passed on to a control apparatus (not shown here), which supplies the drive  23  or the rotary field magnet  14  with current and voltage on the basis of the data supplied by the sensors  19  and  20 , in such a way that an introduction of force can be countered or promoted, in such a way that the entire system is always urged to take on the predetermined zero position thereof. 
     A zero position of this type is shown for example in  FIG. 6 b   , whilst  FIG. 6 a    shows the maximum deflection of the entire system in the positive Z or vertical direction and  FIG. 6 c    shows the maximum deflection of the entire system in the negative Z or vertical direction, respectively. 
     To damp the oscillation introduced into the device according to the invention by the spring apparatus  3  after a force is applied, a shock absorber  21  is provided, one end of which is likewise arranged on the floating bearing transverse connection  30 , whilst the other end thereof is arranged in the upper region of the first inner link  7  of the first scissors. 
       FIG. 7  shows a possible embodiment of an actuating element  4 . In this respect, the actuating element  4  consists of the drive  23  in the form of a rotary field magnet  14 , by means of which the coupling rod  16  in the form of a recirculating ball screw  15  can be moved back and forth. In the present embodiment, the screw pitch of the recirculating ball screw  15  is approximately 45°, it being possible to produce a stroke of 7 cm when rotating the recirculating ball screw by 180° and a stroke of 14 cm when rotating the recirculating ball screw by 360°.  FIG. 8  is a graph of this stroke/revolution ratio. 
       FIG. 9 , however, shows a further embodiment of a possible actuating element  4  for a device according to the invention. In contrast with the actuating element  4  from  FIG. 7 , in this respect, the coupling rod  16  in the form of a recirculating ball screw  15  comprises two spring elements  17  and  18 . These spring elements  17  and  18  ensure that they are initially biased when a force is introduced into the device according to the invention and that subsequently the rotational movement of the coupling rod  16  in the form of a recirculating ball screw  15  is introduced. As a result of this coupling by means of the spring elements  17  and  18 , permanent entrainment of the drive  23  in the form of a rotary field magnet  14  in rotation can be prevented, in particular in the high-frequency or short-stroke operating range, respectively of the device according to the invention. The spring characteristic of the spring elements  17  and  18  are superposed with the spring characteristic  42  of the spring  5 . In this respect, the usable field of forces consists of the spring rate of the spring  5 , the spring rate of the spring elements  17  and  18  and the force spectrum of the drive  23  in form of a rotary field magnet  14 . 
       FIG. 11  is a corresponding force-deflection diagram for the actuating element  4  in accordance with  FIG. 7 , while  FIG. 12  is a corresponding force-deflection diagram of the actuating element  4  from  FIGS. 9 and 10 . 
     As already mentioned, in this respect, reference numeral  43  denotes the spring characteristic of the springs  17  and  18  and reference numeral  42  denotes the spring characteristic of the spring  5 . Further, a target level line  40  is shown in the graphs, and which is taken on by the device according to the invention when a predetermined weight or a predetermined force, respectively is applied thereto. For example, the deflection of the upper suspension part  1  or the change in distance, respectively between the upper suspension part  1  and the lower suspension part  2  is approximately 90 mm for an applied force of 1000 N. 
     In this respect, in the present embodiment,  FIG. 6 b    shows the deflection of 90 mm, whilst  FIG. 6 a    shows a deflection of 0 mm and  FIG. 6 c    shows a deflection of 180 mm. In the two force-deflection diagrams of  FIGS. 11 and 12 , reference numeral  41  indicates a target force line, to represent the force of 1000 N. The target force line  41  and the target level line  40  intersect at an intersection point, through which the spring characteristics  42  of the spring  5  and the spring characteristic  43  of the spring elements  17  and  18  also pass. In this respect, reference numerals  44  and  45  indicate an upper force line and a lower force line. In this respect the upper force line  44  denotes the force which can be introduced by the actuating element  4  in addition to the force acting on the device, whilst the lower force line  45  indicates a force which counters the force introduced into the device. In the present embodiment, this force to be additionally introduced is approximately 200 N. 
     Thus, by means of the device according to the invention, in particular as shown in  FIGS. 1 to 5 , an actuating element  4  in accordance with  FIG. 7  or in accordance with  FIGS. 9 and 10 , respectively being installed, the deviation of the upper suspension face  4  from the target level line  7  can be minimised during the operation of the device according to the invention, in such a way that a vehicle seat equipped therewith substantially maintains the position thereof about this target level line  9 , with optimum suspension comfort and damping comfort. 
     LIST OF REFERENCE NUMERALS 
     
         
           1  Upper suspension part 
           2  Lower suspension part 
           3  Spring means 
           4  Actuating element 
           5  Spring 
           6  Scissor-type support apparatus 
           7  First inner link 
           8  First outer link 
           10  First scissors 
           11  Second inner link 
           12  Second outer link 
           13  Second scissors 
           14  Rotary field magnet 
           15  Recirculating ball screw 
           16  Coupling rod 
           17  Spring element 
           18  Spring element 
           19  Movement sensor 
           20  Acceleration sensor 
           21  Shock absorber 
           22  Fixing element 
           23  Drive 
           24  Floating bearing transverse connection 
           24 ′ Floating bearing transverse connection 
           25  Fixed bearing 
           25 ′ Fixed bearing 
           26  Guide rail 
           27  Guide rail 
           28  Guide rail 
           29  Guide rail 
           30  Floating bearing transverse connection 
           31  Floating bearing transverse connection 
           32  Roller 
           33  Roller 
           40  Target level line 
           41  Target force line 
           42  Spring characteristic of the spring  5   
           43  Spring characteristics of the springs  17  and  18   
           44  Upper force line 
           45  Lower force line 
         X Longitudinal direction 
         Y Width direction 
         Z Vertical direction