Abstract:
The invention relates to a vehicle seat with a height-adjustable seat frame which comprises at least two seat frame parts which can move relative to one another and at least one fluid spring, in particular an air spring, arranged on the seat frame parts for height adjustment purposes, with at least one control device which is provided for influencing the fluid spring and which comprises at least one valve device with control valves which is attached to the first seat frame part and is designed to control fluid flows for the fluid spring, and also a control element which is provided on a second seat frame part and is designed to actuate the control valves, so that a height adjustment and/or damping oscillatory movement of the vehicle seat is ensured, wherein the valve device comprises an internally cylindrical component with at least one rod element arranged displaceably therein as a control element, wherein at least one fluid intake and discharge opening of the rod element can selectively be assigned to one of the control elements by a relative displacement of the cylindrical component and the rod element with respect to one another.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a convention application of German Application Serial Number 10 2007 030 467.8, filed Jun. 29, 2007, which application is hereby incorporated by this reference in its entirety. 
       BACKGROUND OF THE INVENTION 
       [0002]    The invention relates to a vehicle seat with a height-adjustable seat frame which comprises at least two seat frame parts which can move relative to one another and at least one fluid spring, in particular an air spring, arranged between the seat frame parts for height adjustment purposes, with at least one control device which is provided for influencing the fluid spring and which comprises at least one valve device with control valves which is attached to the first seat frame part and is designed to control fluid flows for the fluid spring, and also a control element which is provided on a second seat frame part and is designed to actuate the control valves, according to the preamble of claim  1 . 
         [0003]    EP 0 710 606 2 discloses a vehicle seat with a height-adjustable seat frame which is composed of two seat frame parts which can move in a scissors-like manner with respect to one another and of a seat surface arranged thereon and has a control link which is attached to one seat frame part and also a valve device with control valves which is connected to the other seat frame part and is designed to control gas flows for a fluid spring. A control device composed of this valve device with the control valves and the control link serves for adjusting the height of the scissors-type seat frame parts by means of the fluid spring, by supplying air to or discharging air from the latter. By means of an adjustment device and regardless of a relative position of the seat frame part, the control link is adjusted by a relative movement with respect to the second seat frame part such that a movement of the control link relative to the second seat frame part brought about by the adjustment device causes a height adjustment of the vehicle seat. Here, the control link is designed in the manner of a disc and is able, through its rotational movement, to operate control levers so as to actuate the control valves. The rotational movement of the control link can be carried out by means of a latching mechanism. Such latching mechanisms disadvantageously require adaptation to the switching travels of the control valves, in order to ensure a functional reliability of the height adjustment. The resulting tolerances that have to be taken into account as a result of the required adaptation could lead to an undesired premature or late switching of the control valves. 
         [0004]    In addition, in order to carry out the normal oscillatory suspension movement without any desired height adjustment, there is a paramount need for a small throttle cross section on the control valves in order to obtain an optimised oscillatory movement of the vehicle seat in the height direction. However, when simultaneously using the control device for desired height adjustments, this leads to long lifting times of the vehicle seat, since only a small supply of air via the inlet throttle path is possible for such a desired height adjustment. Therefore, only a very slow height adjustment is possible. 
       SUMMARY OF THE INVENTION 
       [0005]    Accordingly, the object of the present invention is to provide a vehicle seat with a height-adjustable seat frame which, by means of a fluid spring, in particular an air spring, and a control device, is able to carry out height adjustments and oscillatory movements, said vehicle seat allowing a height adjustment at a selectable speed and an optimised air intake to and discharge from the air spring as a function of the spring travel of the air spring. 
         [0006]    The core concept of the invention is, in a vehicle seat with a height-adjustable seat frame which comprises at least two seat frame parts which can move relative to one another and at least one fluid spring arranged between the seat frame parts and a base for height adjustment purposes, with at least one control device which is provided for influencing the fluid spring and which comprises at least one valve device with control valves which is attached to the first seat frame part and is designed to control fluid flows for the fluid spring, and also a control element which is provided on a second seat frame part and is designed to actuate the control valves, so that a height adjustment and/or damping oscillatory movement of the vehicle seat is ensured, the valve device comprises an internally cylindrical component with at least one rod element arranged displaceably therein as a control element. The rod element is provided with at least one fluid intake and discharge opening which can selectively be assigned to one of the control valves by a relative displacement of the cylindrical component and the rod element with respect to one another. Such a slide valve, which is preferably arranged next to a damping element, not only advantageously allows a precise adaptation of the quantity of air supplied to and discharged from the air spring for the current spring travel of the air spring, but also allows a simplified design of such a height adjustment device since there is no longer any need to use control links of complicated construction with latching devices and the like. This also results in low manufacturing costs. 
         [0007]    A fluid spring is to be understood to mean both a gas spring and also a spring which functions on the basis of fluid supplied thereto and discharged therefrom. Such a gas spring may in particular be designed as an air spring. Accordingly, the fluid flows may be gas flows, in particular air flows, or liquid flows. The fluid intake and discharge opening can likewise be configured as an intake and discharge opening for gases, in particular air, or liquids. 
         [0008]    The air spring may be arranged between one of the seat frame parts and on a base of the vehicle seat, preferably in the vertical direction, so that the forces act on the vehicle seat preferably in the vertical direction. Of course, such an air spring may also be arranged in some other way, such as for example between the two scissors-type frames that can move relative to one another. 
         [0009]    During a normal oscillatory movement of the vehicle seat, as a result of the proportional excursion of the gas spring relative to the internally cylindrical component, a respectively adapted quantity of air is supplied to or discharged from the gas spring in a targeted manner in order to improve the damping properties thereof. This results in a very good oscillatory property of the vehicle seat in the height direction. 
         [0010]    Preferably, the gas intake and discharge opening on the surface of the rod element is provided with at least one notch extending in the longitudinal direction of the rod element with a deepest point in the centre with reference to the longitudinal direction, wherein according to one preferred embodiment the notch may extend at an angle with respect to the longitudinal direction of the rod element or is formed in the longitudinal direction of the rod element. Due to the different depths, such a notch allows a targeted supply and discharge of air in a desired quantity so that, during a desired, e.g. manual, height adjustment of the vehicle seat, a low air throughput is obtained for a small movement of the actuation element or a single actuation of the height adjustment actuation element. This results in a gentle, precise movement of the vehicle seat undergoing height adjustment towards the desired point. 
         [0011]    Likewise, a medium air throughput is obtained when the height adjustment actuation element is actuated twice, or a high air throughput is obtained when it is actuated three times or in the case of rapid lowering actuation, resulting in a faster movement of the height-adjustable vehicle seat which is slowed upon reaching the desired target position. 
         [0012]    The gas intake and discharge opening on the surface of the rod element may comprise at least several bores arranged one behind the other in the longitudinal direction of the rod element or arranged one behind the other at an angle with respect to the longitudinal direction of the rod element, said bores having diameters which increase from bore to bore. This likewise allows a greater or lesser intake and discharge of air to and from the gas spring, depending on which bore the air passes through. Ideally, the bores are arranged in such a way that the bore with the largest diameter is arranged centrally in the running direction of the bores, and bores with increasingly smaller diameters are arranged towards the ends. 
         [0013]    The internally cylindrical component has at least two sealing elements which annularly surround the rod element and are designed to form at least two separate gas chambers arranged one behind the other within a cylinder jacket of the cylindrical component, so that as a result the gas intake and discharge opening allows a greater or lesser supply and discharge of air to or from the gas chambers upon passing over the sealing element by a selectable distance during a desired height adjustment. Ideally, in this case, a first gas chamber is connected to the first control valve and is at an overpressure that is built up pneumatically by means of an external air source. A second chamber is connected to the second control valve and is at normal atmospheric pressure in order thus to serve for air discharge purposes via the second control valve arranged thereon when air is supplied into this chamber via the air intake and discharge opening. By contrast, the first gas chamber is provided so that it passes air via the air intake and discharge opening to the gas spring, wherein in this case advantageously the rod element has along its longitudinal direction, at least partially, a cavity with a gas spring connection opening at its first end and the gas intake and discharge opening at its second end. 
         [0014]    An adjustment device arranged at the end of the rod element serves to adjust the displaceable rod element by a relative movement with respect to the internally cylindrical component such that a movement of the rod element relative to the cylindrical component that is brought about by the adjustment device causes a height adjustment of the vehicle seat at a predefinable speed by displacing the gas intake and discharge opening into the first or second gas chamber. 
         [0015]    At least one spring element serves for applying a spring force to the adjustment movement of the rod element. 
         [0016]    The rod element is suspended in an articulated manner on the second seat frame part, whereas the cylindrical component is suspended in an articulated manner on the first seat frame part. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    Advantages and expedient features will become apparent from the following description in conjunction with the drawing, in which: 
           [0018]      FIGS. 1   a - c  show a vehicle seat in various height positions; 
           [0019]      FIG. 2  shows a perspective view of part of the vehicle seat frame with a height adjustment device arranged therein and an air spring; 
           [0020]      FIG. 3  shows a view, in partial cross section, of part of a vehicle seat frame with the air spring and the height adjustment device; 
           [0021]      FIG. 4  shows, in a side view, part of the vehicle seat with the height adjustment device in cross section in a first operating position; 
           [0022]      FIG. 5  shows part of the vehicle seat with a height adjustment device in cross section in a second operating position; 
           [0023]      FIG. 6   a  shows the vehicle seat frame with the height adjustment device according to the invention in a first position; 
           [0024]      FIG. 6   b  shows, in a cross-sectional view along the section line A//A in  FIG. 6   a , the height adjustment device in the first position; 
           [0025]      FIG. 7   a  shows the vehicle seat frame with the height adjustment device according to the invention in a second position; 
           [0026]      FIG. 7   b  shows, in a cross-sectional view along the section line A//A in  FIG. 7   a , the height adjustment device in a second position; 
           [0027]      FIG. 8   a  shows the vehicle seat frame with the height adjustment device according to the invention in a third position; 
           [0028]      FIG. 8   b  shows, in a cross-sectional view along the section line A//A, the height adjustment device in a third position; 
           [0029]      FIG. 9   a  shows the vehicle seat frame with the height adjustment device according to the invention in a fourth position; 
           [0030]      FIG. 9   b  shows a detail A, as marked in  FIG. 9   a;    
           [0031]      FIG. 10   a  shows a rod element for the height adjustment device in cross section according to a first variant; 
           [0032]      FIG. 10   b  shows the rod element shown in  FIG. 10   a  rotated through 90°; 
           [0033]      FIG. 11   a  shows a rod element in cross section according to a second variant; 
           [0034]      FIG. 11   b  shows the rod element according to the second variant rotated through 90°; 
           [0035]      FIG. 12   a  shows the rod element in cross section according to a third variant; 
           [0036]      FIG. 12   b  shows the rod element according to  FIG. 12   a  rotated through 90°; 
           [0037]      FIG. 12   c  shows a detail of the rod element according to the third variant, and 
           [0038]      FIG. 13  shows a perspective view of the height adjustment device with an adjustment device in the form according to the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0039]      FIGS. 1   a - c  show a vehicle seat with a backrest  1  and a seat part  2 , which is shown in various height positions. The lowest seat position of the vehicle seat in  FIG. 1   a  shows a folded-together scissors-type seat frame with an air spring  3  designed as a gas spring and with a control device  4  or height adjustment device. 
         [0040]    The air spring  3  is connected by a lower end to a base of the vehicle seat or a body part or another element (not shown) that is fixedly connected to the body, and is connected by an upper end to at least one part of the scissors-type seat frame. 
         [0041]    The seat is arranged on rails  5 ,  6  such that it can be displaced in the forward and backward direction. 
         [0042]      FIGS. 1   b  and  1   c  show the first seat frame part  7  and the second seat frame part  8 , wherein both the control device  4  and a spring-type damping element  3   a  are attached by first ends  3   b  and  4   a  to the bottom of the first seat frame part  7  and by second, upper ends  3   c  and  4   b  to the second seat frame part  8 . 
         [0043]    When the vehicle seat is moved in the upward direction in  FIG. 1   c , both the damping element  3   a  and the control device  4  are in an extended state. 
         [0044]      FIG. 2  shows part of the vehicle seat frame in the region of the damping element  3   a  and the control device  4 . The control device  4  consists of an internally cylindrical component  12 , which at the bottom is arranged with the end  4   a  articulated about a pivot pin  9  on the first seat frame part  7 , which has a groove on the outer side. 
         [0045]    The internally cylindrical component  12  is arranged such that it can be displaced with respect to a shaft  11  and has control valves  13  and  14  on the outer side. 
         [0046]    The shaft  11  is attached at the top to the seat frame part  8  by means of a pivot pin  10 . 
         [0047]    A rod element  15 , which is arranged such that it can be displaced within the internally cylindrical component  12 , is arranged in a fixed position at its upper end  15   b  relative to the second seat frame part  8 , as can be seen from  FIG. 3 . 
         [0048]    The rod element  15  has at the bottom at its lower end  15   a  a gas spring connection opening which is connected to a cavity  16  within the rod element  15 . 
         [0049]    The rod element  15  is arranged within the component  12  by means of annular sealing elements  17 ,  18 ,  19  and  20 , wherein the sealing elements separate two gas chambers  21 ,  22  arranged in a cylinder jacket of the component  12 . The first gas chamber  21  contains air at an overpressure, whereas the second gas chamber  22  is at normal pressure, i.e. atmospheric pressure. 
         [0050]      FIG. 4  shows a cross section through part of the vehicle seat frame with the slide valve or control device  4  arranged therein. The slide valve is shown in a first slide position in  FIG. 4  and in a second slide position in  FIG. 5 . 
         [0051]    It can clearly be seen from the view of the slide valve shown in  FIG. 4  that the bore  16  within the rod element  15  has a gas spring connection  38  at its first end  16   a  and, at its second end  16   b , on the left and on the right or at the top and at the bottom, two openings  25   a  with adjoining notches  26 ,  27  which are formed in the surface of the rod element  15  and which are illustrated in greater detail with reference to  FIGS. 10   a ,  10   b ,  11   a ,  11   b  and  12   a - c.    
         [0052]    In the neutral position (shown here) of these gas intake and discharge openings  25   a ,  26 ,  27  between the two gas chambers  21 ,  22  and the two seals  18 ,  19 , air is neither supplied to nor discharged from the gas spring, which in respect of air intake and discharge is connected via the element  38  to the slide valve. 
         [0053]    By contrast, in the position of the rod element  15  and thus of the second end  16   b  of the bore  16  shown in  FIG. 5 , the openings  26 ,  27  are located in the region of the first gas chamber  21 , which is at an overpressure and thus supplies air to the gas spring via the openings  26 ,  27  and the bore  16  and also the element  38 . 
         [0054]      FIGS. 6   a ,  6   b ,  7   a ,  7   b ,  8   a ,  8   b  and  9   a ,  9   b  show the vehicle seat frame with the control device and/or the height adjustment device and/or the slide valve in various height adjustment positions. When a height adjustment actuation element is actuated, the rod element  15  can be displaced downwards or upwards in relation to the internally cylindrical component  12  by means of an adjustment device (shown in greater detail in  FIG. 13 ) in the form of a Bowden cable  40  at its upper end  15   b , in order thus to arrange the gas or air intake and discharge openings either in the region of the gas chamber  21  or in the region of the gas chamber  22  or in a section  30  arranged therebetween. 
         [0055]    In the neutral position of the rod element  15  with respect to the component  12  shown in  FIGS. 6   a  and  6   b , the gas intake and discharge openings and thus the end  16   b  of the bore  16  are arranged in the section  30  in which there is no access to a gas volume for the openings. 
         [0056]    This can also be seen from the cross section shown in  FIG. 6   b  along the line A//A according to  FIG. 6   a , which shows that no air can escape or be supplied between the sealing element  18  and the surface of the rod element  15 . 
         [0057]    The rod element is pushed into the component  12  by one step in  FIG. 7  and by two steps in  FIG. 8 , in order thus to achieve a desired height adjustment. The different distances are illustrated by references  29 ,  32 ,  33  and in  FIG. 9   a  by reference  34 . 
         [0058]    By comparing  FIGS. 6   a ,  7   a ,  8   a  and  9   a , it can be seen that the end  16   b  of the bore  16  is increasingly pushed in the direction of the air intake chamber  21 , wherein, in the rod element end position shown in  FIG. 7   a , the notch  26 ,  27  is arranged with a first part and in  FIG. 8   a  with a second part in the region of the chamber  21 . This means that it is not the entire notch that allows an entry of the air at an overpressure within the chamber  21  into the bore  16  and thus the gas spring, but rather a metering of the supplied air takes place. This is achieved by the notch effect with different depths, as will be described in further detail below in connection with  FIGS. 10   a ,  10   b  for example. 
         [0059]    In the region of reference  31  shown in  FIGS. 6   b ,  7   b  and  8   b , an opening of greater or lesser size for supplying air into the opening  16  is thus obtained. 
         [0060]    A pivot pin  28  holds the two scissors-type frames  7 ,  8  together at their centre point. 
         [0061]    In  FIG. 9   a , the vehicle seat frame is shown in its lowermost position. This corresponds to a contracted spring position, with this being a rapid lowering actuation. In  FIG. 9   b , the enlarged detail view shows that the notches  26 ,  27  are now arranged completely in the region of the overpressure gas chamber  21 . 
         [0062]    In the neutral position of the rod element shown in  FIG. 6   a , no activities are taking place. In the position of the rod element shown in  FIG. 7   a , air is supplied to the gas spring only slowly due to the small available cross section of the air intake and discharge openings, so that the seat slowly moves upwards to the neutral position that is set automatically, as shown in  FIG. 6   a.    
         [0063]    In  FIG. 8   a , a larger cross section of the notches or air supply and discharge openings is available, so that air enters the bore  16  more quickly and the seat accordingly moves upwards more quickly. Before reaching the end position, a slower upward movement or a slowing-down of the upward movement of the vehicle seat takes place, since the rod element automatically moves back towards the neutral position, i.e. towards the section  30 . The neutral position of the rod element is then assumed automatically again by the upward movement of the seat and therefore the excursion of the gas spring and thus also the relative movement that takes place between the component  12  and the rod element  15 . 
         [0064]    A height adjustment in the downward direction accordingly works in precisely the reverse order, i.e. the slide is displaced in the direction of the chamber  22  which brings about a discharge of air from the air spring via the control valve  14 . 
         [0065]    In the seat frame position shown in  FIG. 9 , the seat is completely lowered when the rapid lowering button is activated. 
         [0066]      FIGS. 10   a  and  10   b  show, in a cross-sectional view and in a plan view, a rod element according to a first variant. It can be seen from these figures that the rod element has at its first end  15   a  the gas spring connection opening  38  for connection to the gas spring  3  and has notches  26 ,  27 , as also shown on an enlarged scale. The notch  27  has the deepest point in its central region  27   a , so that a metered intake and discharge of air is possible depending on the position of the notch with respect to the sealing elements  18 ,  19 . 
         [0067]    A fixing element  35  for fixing the rod element to the second seat frame part  8  is arranged at the second end  15   b  of the rod element. 
         [0068]    A bore  25   a  arranged in the air intake and discharge opening establishes the connection to the bore  16  arranged within the rod element. 
         [0069]      FIGS. 11   a  and  11   b  show another variant of the rod element in cross section and in plan view. In this variant, there is a notch  36  with through-bores  37   a ,  37   b  which is arranged on the surface of the rod element  15 , wherein the notch is arranged at an angle with respect to the longitudinal direction of the rod element  15 . This advantageously makes it possible, as in the embodiment shown in  FIGS. 10   a  and  10   b , for a sealing element or a rubber seal which annularly surrounds the rod element not always to be subjected to stress at the same points when the rod element is displaced relative to the component  12 , and thus delays wear on the sealing elements. 
         [0070]      FIGS. 12   a ,  12   b  and  12   c  show a further variant of the rod element in a cross-sectional view, in plan view and in a detail view. This variant differs from the variants of the rod elements which have notches in that they have individual bores  39   a - e  which have different diameters. 
         [0071]    The diameter of the bores  39   a  and  39   e  are graduated such that the bore with the largest diameter is arranged in the centre, i.e. the bore  39   c . The bores with the smallest diameter  39   a  and  39   e  are arranged at the ends of the row of bores. As in the case of the rod elements with the notches, this advantageously produces the effect that a metered intake and discharge of air via the bore  16  is possible, depending on the displacement travel of the rod element  15 . 
         [0072]      FIG. 13  shows a perspective view of the slide valve with the adjustment device arranged thereon. The adjustment device consists of a Bowden cable  40  which makes it possible for the rod element  15  to be displaced counter to a tensile spring force exerted by the tension springs  42 ,  43  relative to a component which is arranged in a fixed position on the seat frame part  8  and which arrests the Bowden cable  40 . This is indicated by the double arrow  41  and thus allows a targeted and desired height adjustment of the vehicle seat, since the rod element  15  is thus displaced relative to the component  12  and thus relative to the sealing elements  18 ,  19  and also the gas chambers  21 ,  22 . 
         [0073]    All of the features disclosed in the application documents are claimed as essential to the invention in so far as they are novel individually or in combination with respect to the prior art. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 List of references 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                  1 
                 backrest 
               
               
                   
                  2 
                 seat part 
               
               
                   
                  3 
                 fluid spring, in particular air spring 
               
               
                   
                  3a 
                 damping element 
               
               
                   
                  3b, 4a 
                 first ends on the first seat part frame 
               
               
                   
                  3c, 4b 
                 second ends on the second seat part frame 
               
               
                   
                  4 
                 control device 
               
               
                   
                  5, 6 
                 rails 
               
               
                   
                  7 
                 first seat frame part 
               
               
                   
                  8 
                 second seat part frame 
               
               
                   
                  9 
                 pivot pin 
               
               
                   
                 10 
                 pivot pin 
               
               
                   
                 11 
                 shaft 
               
               
                   
                 12 
                 internally cylindrical component 
               
               
                   
                 13, 14 
                 control valves 
               
               
                   
                 15 
                 rod element 
               
               
                   
                 15a 
                 lower end 
               
               
                   
                 15b 
                 upper end 
               
               
                   
                 16 
                 cavity/bores 
               
               
                   
                 16a 
                 first end 
               
               
                   
                 16b 
                 second end 
               
               
                   
                 17, 18, 19, 20 
                 sealing elements 
               
               
                   
                 21, 22 
                 gas chambers 
               
               
                   
                 23 
                 rotation axis on the first seat frame part 
               
               
                   
                 24 
                 rotation axis on the second seat frame part 
               
               
                   
                 25a, 25b, 26, 27; 
               
               
                   
                 36, 37a, 37b; 
               
               
                   
                 39a-e 
                 gas intake and discharge openings 
               
               
                   
                 26, 27, 36 
                 notches 
               
               
                   
                 28 
                 pivot pin 
               
               
                   
                 29, 32, 33, 34 
                 distances 
               
               
                   
                 30 
                 section 
               
               
                   
                 31 
                 opening 
               
               
                   
                 35 
                 fixing element 
               
               
                   
                 37a, 37b 
                 through-bores 
               
               
                   
                 38 
                 gas spring connection 
               
               
                   
                 39a-e 
                 bores 
               
               
                   
                 39a, 39e 
                 diameters 
               
               
                   
                 40 
                 Bowden cable 
               
               
                   
                 41 
                 double arrow 
               
               
                   
                 42, 43 
                 tension springs