Abstract:
The invention relates to a hydraulic accumulator device in the form of a membrane accumulator, comprising a membrane ( 16 ) which separates a pneumatic volume from a hydraulic volume. In order to improve said hydraulic accumulator device with respect to the degree of efficiency and/or manufacturing costs, the membrane ( 16 ) is tensioned between two holding bodies ( 4,5 ) which respectively comprise several recesses ( 11 - 14 ) and between which the membrane ( 16 ) is tensioned in order to produce several hydropneumatic membrane accumulators.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The invention relates to a hydraulic accumulator device constructed as a diaphragm accumulator, having a diaphragm which separates a pneumatic volume from a hydraulic volume. 
       SUMMARY OF THE INVENTION 
       [0002]    It is an object of the invention to improve a hydraulic accumulator device constructed as a diaphragm accumulator, having a diaphragm which separates a pneumatic volume from a hydraulic volume, with regard to its efficiency and/or its production costs. 
         [0003]    The object is achieved, in the case of a hydraulic accumulator device constructed as a diaphragm accumulator, having a diaphragm which separates a pneumatic volume from a hydraulic volume, in that the diaphragm is clamped between two holding bodies which have in each case a plurality of depressions and between which the diaphragm is clamped in order to form a plurality of hydropneumatic diaphragm accumulators. The holding bodies are preferably of plate-like form. One of the holding bodies delimits a plurality of pneumatic volumes. The other holding body delimits a plurality of hydraulic volumes. By means of the hydraulic accumulator device according to the invention, it is possible in a simple manner for a hydraulic accumulator field having a multiplicity of hydropneumatic diaphragm accumulators to be realized. In the hydraulic accumulator device according to the invention, it is also possible in a simple manner for a plurality of hydraulic accumulator fields to be combined with one another. The shape and the size of the hydraulic accumulator fields can be adapted in a simple manner to a given installation space. 
         [0004]    A preferred exemplary embodiment of the hydraulic accumulator device is characterized in that the depressions of the holding bodies face toward one another in pairs in order to form in each case one hydropneumatic diaphragm accumulator. The depressions of one holding body delimit a multiplicity of hydraulic volumes. The depressions of the other holding body delimit a multiplicity of pneumatic volumes. The hydraulic volumes and pneumatic volumes are assigned to one another in pairs and are separated from one another by the diaphragm. This yields, with few components, a multiplicity of diaphragm accumulators. 
         [0005]    A further preferred exemplary embodiment of the hydraulic accumulator device is characterized in that the holding bodies are connected to one another between the depressions. The holding bodies preferably bear areally against one another between the depressions. In said areal regions, the holding bodies are connected to one another at least in punctiform fashion for example by means of fastening elements. 
         [0006]    A further preferred exemplary embodiment of the hydraulic accumulator device is characterized in that the depressions have the shape of spherical segments or combs. The spherical segments or combs are outwardly bulged. The combs have for example a hexagonal cross section in the manner of honeycombs. 
         [0007]    A further preferred exemplary embodiment of the hydraulic accumulator device is characterized in that the holding bodies have in each case at least one connector, and/or in that the depressions assigned to in each case one of the holding bodies are fluidically connected to one another. The connector may comprise for example a pneumatic connector duct or a hydraulic connector duct. The individual depressions may be hydraulically or pneumatically connected to one another. The connector ducts may be formed for example by sickle-shaped deformations of the holding bodies. 
         [0008]    A further preferred exemplary embodiment of the hydraulic accumulator device is characterized in that, in the holding bodies, there are formed connecting ducts by means of which depressions assigned to in each case one of the holding bodies are fluidically connected to one another. The connecting ducts may, in a simple manner, be formed by sickle-shaped deformations of the holding bodies. 
         [0009]    A further preferred exemplary embodiment of the hydraulic accumulator device is characterized in that the diaphragm is pre-shaped, reinforced and/or supported in the region of the connecting ducts and/or of the depressions. The diaphragm may for example be supported by supporting rings. On the supporting rings there may be formed supporting collars, the shape of which is adapted to the shape of the depressions. 
         [0010]    A further preferred exemplary embodiment of the hydraulic accumulator device is characterized in that a plurality of hydraulic accumulator fields which comprise in each case two holding bodies and one diaphragm are mechanically and/or fluidically coupled to one another. The mechanical coupling of the hydraulic accumulator fields may be realized for example by means of tie rods. The fluidic coupling of the hydraulic accumulator fields may be realized for example by means of correspondingly designed coupling elements and/or lines. 
         [0011]    A further preferred exemplary embodiment of the hydraulic accumulator device is characterized in that the holding bodies are provided as plate-like main bodies with the depressions. The holding bodies with the plate-like main bodies may be formed from a deep-drawn or stamped sheet-metal material. The holding bodies with the plate-like main bodies may also be formed from a laminated fiber-composite plastics material. The holding bodies may for example be formed as CFRP plates. The abbreviation CFRP stands for a Carbon Fiber Reinforced Plastic composite, that is to say a plastics material reinforced with carbon fibers. 
         [0012]    A further preferred exemplary embodiment of the hydraulic accumulator device is characterized in that suitable support rings are inlaid in the region of the depressions, and/or in that the hydropneumatic diaphragm accumulators are clamped by means of tie rods between two supporting plates. 
         [0013]    A further preferred exemplary embodiment of the hydraulic accumulator device is characterized in that, instead of one continuous diaphragm, a plurality of individual diaphragms are used. 
         [0014]    A further preferred exemplary embodiment of the hydraulic accumulator device is characterized in that support rings are formed into the diaphragm. 
         [0015]    A further preferred exemplary embodiment of the hydraulic accumulator device is characterized in that the diaphragm simultaneously performs the function of a seal between the holding bodies. 
         [0016]    The invention also relates to the use of an above-described hydraulic accumulator device as a load-bearing structural component. 
         [0017]    The invention also relates to a diaphragm and/or a holding body for a hydraulic accumulator device as described above. 
         [0018]    The hydraulic accumulator device according to the invention is particularly suitable for mobile hydraulic applications, in particular for motor vehicles with a hydraulic traction drive and for hydraulic hybrid vehicles. By means of the design according to the invention of the hydraulic accumulator device, the integration thereof into a motor vehicle is simplified. The hydraulic accumulator device may be used as a load-bearing component, for example as a floor plate. The vehicle structure can be stiffened in this way. 
         [0019]    The design according to the invention of the hydraulic accumulator device provides inter alia the advantage that a plurality of individual accumulators can be produced in a simple manner in only one manufacturing step. As a result of the special design and arrangement of the holding bodies and of the diaphragm, it is possible for a hydraulic accumulator device having a plurality of hydropneumatic diaphragm accumulators to be produced from only three simple components. The holding bodies and the diaphragm can be produced in a simple and inexpensive manner. By storing a plurality of storage fields one above the other or adjacent to one another, the hydraulic accumulator device according to the invention can be adapted in a simple manner to a predefined installation space. The depressions in the holding bodies are formed preferably by domed formations with relatively small radii. This provides the advantage that relatively thin-walled materials can be used to produce the holding bodies, which has a positive effect on the weight and the material costs of the hydraulic accumulator device. 
         [0020]    Further advantages, features and details of the invention will emerge from the following description, in which various exemplary embodiments are described in detail with reference to the drawing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    In the drawing: 
           [0022]      FIG. 1  is a simplified illustration of a hydraulic accumulator device according to the invention in section; 
           [0023]      FIG. 2  shows a corner of the hydraulic accumulator device from  FIG. 1 , in a plan view; 
           [0024]      FIG. 3  shows a similar hydraulic accumulator device to that in  FIG. 2  with connecting ducts, in a plan view; 
           [0025]      FIG. 4  shows a detail from  FIG. 3  in section ( FIG. 4   a ) and in a plan view ( FIG. 4   b ); 
           [0026]      FIG. 5  shows a detail from  FIG. 1  in section ( FIG. 5   a ) and in a plan view ( FIG. 5   b ), with a connecting duct formed as a bead; 
           [0027]      FIG. 6  shows a detail from  FIG. 1  with a supporting ring; 
           [0028]      FIG. 7  shows the detail from  FIG. 6  in a plan view; 
           [0029]      FIG. 8  shows a similar illustration to  FIG. 6 , with a modified supporting ring; 
           [0030]      FIG. 9  shows the detail from  FIG. 8  in a plan view; 
           [0031]      FIG. 10  shows a similar illustration to  FIG. 8 , with a pre-shaped diaphragm; 
           [0032]      FIG. 10   a  shows a similar illustration to  FIG. 8 , as per a further exemplary embodiment; 
           [0033]      FIG. 11  shows a detail of a hydraulic accumulator device having two hydraulic accumulator fields coupled to one another, in a plan view; 
           [0034]      FIG. 12  shows a hydraulic accumulator field from  FIG. 11  with a connected line; 
           [0035]      FIG. 13  shows a detail of a hydraulic accumulator device with three hydraulic accumulator fields coupled to one another, in section; 
           [0036]      FIG. 14  shows an arrangement, optimized with regard to installation space and forces, of two hydraulic accumulator fields one above the other; and 
           [0037]      FIG. 15  shows a hydraulic accumulator device having a plurality of hydraulic accumulator fields which are connected to one another by means of tie rods. 
       
    
    
     DETAILED DESCRIPTION 
       [0038]      FIGS. 1 and 2  illustrate a detail of a hydraulic accumulator device  1  according to the invention in different views. The hydraulic accumulator device  1  comprises two holding bodies  4 ,  5  which are formed in each case from a substantially plate-like main body  8 ,  9 . The two plate-like main bodies  8 ,  9  are equipped with hemispherical depressions  11 ,  12 ;  13 ,  14 , in a manner similar to a baking tray for cakes, in particular muffins. The holding bodies  4 ,  5  are formed for example from a sheet-metal material. The plate-like main bodies  8 ,  9  are outwardly bulged in the region of the depressions  11 ,  12 ;  13 ,  14  such that the depressions  11 ,  12  and  13 ,  14  of the two holding bodies  4 ,  5  face toward one another. 
         [0039]    Each holding body  4 ,  5  is equipped with a multiplicity of depressions  11 ,  12 ;  13 ,  14 . It can be seen in  FIG. 2  that the depressions  11 ,  12  are distributed uniformly over the plate-like main body  8 . It can be seen in  FIG. 1  that in each case two mutually opposite depressions  11 ,  13  and  12 ,  14  delimit in each case one substantially spherical volume. 
         [0040]    A diaphragm  16  is clamped between the holding bodies  4 ,  5  such that the volumes enclosed by the depressions  11 ,  12  and  13 ,  14  are divided in each case into a pneumatic volume  21  and a hydraulic volume  22 . The pneumatic volume  21 , like the hydraulic volume  22 , has substantially the shape of a hemisphere owing to the shape of the depressions  11  and  13 . 
         [0041]    The two holding bodies  4 ,  5  are fastened to one another, with the interposition of the diaphragm  16 , by means of fastening elements  24 ,  25 . The fastening elements  24 ,  25  extend through the plate-like main bodies  8 ,  9  and the diaphragm  16  perpendicular to the components  8 ,  9  and  16 . Here, the fastening elements  24 ,  25  are arranged not in the region of the depressions  11  to  14  but rather between these. 
         [0042]    The fastening elements  24 ,  25  may for example comprise rivet connection elements or screw connection elements. Alternatively or in addition, the holding bodies  4 ,  5  may be connected to one another in punctiform fashion in a cohesive manner, for example by adhesive bonding or welding. The diaphragm  16  is interrupted, or provided with a through hole, in the region of the connection between the holding bodies  4 ,  5 . 
         [0043]    The pneumatic volumes  21  of the hydraulic accumulator device  1  are filled with a pneumatic medium, such as gas, during operation. The hydraulic volumes  22  of the hydraulic accumulate device  1  are filled with a hydraulic medium, such as oil, during operation. To be filled, the individual pneumatic volumes  21  and hydraulic volumes  22  at the oil and gas sides must be connected to one another and, via connectors, to the outside. 
         [0044]      FIGS. 3 and 4  illustrate, on the basis of the example of a holding body  34 , that the depressions  11 ,  12  or the pneumatic volumes enclosed by the depressions  11 ,  12  and the diaphragm are fluidically, that is to say pneumatically, connected to one another by a connecting duct  36 . The pneumatic volume delimited by the depression  11  is connected to a pneumatic volume delimited by a depression  38  by a further connecting duct  37 . 
         [0045]    It can be seen in  FIG. 3  that the connecting ducts  36 ,  37  are arranged in a uniformly distributed manner between the pneumatic volumes. The holding body  5  which serves for delimiting the hydraulic volumes is preferably of the same design as the holding body  34  with the pneumatic volumes. According to a further aspect of the invention, connecting ducts of the hydraulic volumes may be arranged offset with respect to connecting ducts of the pneumatic volumes so as not to impair the stability of the holding bodies. 
         [0046]    It is indicated in  FIG. 5  that the inflow and outflow into and out of the pneumatic volume of the depression  11  can be optimized by virtue of the connecting duct  36  being continued in a bead  40 . 
         [0047]    In  FIG. 5 , the diaphragm  16  is illustrated in a state in which it bears at the inside against the depression  11 . In the region of the connecting duct  36  or of the bead  40 , the diaphragm  16  may be clamped in a non-optimum manner between the holding bodies. 
         [0048]      FIGS. 6 to 9  show how the clamping of the diaphragm  16  between the holding bodies  34  and  5  can be improved through the use of supporting rings  41 ,  42 ;  45 ,  46 . 
         [0049]    In the exemplary embodiment illustrated in  FIGS. 6 and 7 , the supporting rings  41 ,  42  are designed as simple rings, the diameter of which corresponds to the diameter of the depressions  11 ,  12 . The supporting rings  41 ,  42  prevent the diaphragm  16  from deforming into the connecting duct  36 . 
         [0050]    In the exemplary embodiment illustrated in  FIGS. 8 and 9 , the supporting rings  45 ,  46  are additionally provided with a supporting collar  47 ,  48  which extends into the depression  11 ,  12 . The design of the collars  47 ,  48  is adapted to the design of the associated depression  11 ,  12 . The supporting collar  47 ,  48  prevents the diaphragm  16  from deforming into a bead, as denoted by  40  in  FIG. 5 . 
         [0051]    It is indicated in  FIG. 10  that the diaphragm need not imperatively have a planar form. In  FIG. 10 , there is clamped between the holding bodies  4 ,  5  a diaphragm  56  which comprises pre-shaped regions  61 ,  62  in the region of the depressions  11 ,  12 . The pre-shaped regions  61 ,  62  have the shape of a hemisphere which is adapted to the shape of the depression  11 ,  12 . Further forms such as for example that shown in  FIG. 10   a  are also possible. 
         [0052]      FIG. 11  shows that, in a hydraulic accumulator device  71  according to the invention, two or more hydraulic accumulator fields  72 ,  73  can be combined with one another in a simple manner. Each hydraulic accumulator field  72 ;  73  comprises a multiplicity of hydropneumatic diaphragm accumulators  74 ,  75 ;  76 ,  77 . The two hydraulic accumulator fields  72 ,  73  are fluidically coupled to one another by means of a coupling element  80 . The coupling element  80  connects two connector ducts  78 ,  79  to one another. The connector duct  78  extends from a pneumatic volume or a hydraulic volume of the hydropneumatic diaphragm accumulator  75 . The connector duct  79  extends from a pneumatic volume or hydraulic volume of the hydropneumatic diaphragm accumulator  76 . 
         [0053]    It is shown in  FIG. 12  that a line  85  may also be connected to the connector duct  78  of the hydraulic accumulator field  72  by means of a coupling element  84 . The line  85  may be in the form of a hydraulic line or pneumatic line. 
         [0054]    It is indicated in  FIG. 13  that, in a hydraulic accumulator device according to the invention, two or more hydropneumatic accumulator fields  91 ,  92 ,  93  may also be arranged one above the other. In this arrangement of the accumulator fields  91  to  93  one above the other, it is possible for the otherwise unutilized volumes between the individual accumulators to advantageously be utilized as a low-pressure volume. The low-pressure volume may for example be filled with a hydraulic medium which is at low pressure. 
         [0055]    In  FIG. 13 , the accumulator field  92  comprises two holding bodies  95 ,  96 , between which a diaphragm  98  is clamped. The accumulator field  93  comprises two holding bodies  100 ,  101 , between which a diaphragm  103  is clamped. In the region of a depression  105  of the holding body  101 , a line  108  is connected to the illustrated hydraulic accumulator device by means of a coupling element  106 . According to a further aspect of the invention, the diaphragm  103  is provided with a through hole  110  which connects the volume in the depression  105  to the volume in a depression  111  of the holding body  100 . The volume enclosed by the depression  111  is connected via a further coupling element  112  to a volume  114  of the holding body  96 . The volume  114  is in turn connected via a through hole  118  to a volume  115  of the holding body  95 . 
         [0056]    It is shown in  FIG. 14  that, in the case of an arrangement of two accumulator fields  121 ,  122  one above the other, an existing installation space can be optimally utilized by virtue of the accumulator fields  121 ,  122  being arranged offset relative to one another. In the case of the offset arrangement, the hemispheres, formed by the depressions, of the holding bodies can be supported on one another in punctiform fashion. As a result of the stabilization associated with this, the wall thickness of the holding bodies can be reduced. In connection with the offset arrangement of the accumulator fields  121 ,  122 , a comb-shaped form of the depressions has proven to be particularly advantageous. 
         [0057]      FIG. 15  illustrates how three accumulator fields  131  to  133  arranged one above the other can be mechanically coupled to one another in a particularly stable manner by means of tie rods  141  to  144 . The tie rods  141  and  142  extend between the holding bodies of the accumulator fields  131  and  133 . The tie rods  143 ,  144  extend between two supporting plates  151 ,  152  between which the three accumulator fields  131  to  133  are clamped. 
         [0058]    The combinations, illustrated in  FIGS. 13 to 15 , of a plurality of accumulator fields in a hydraulic accumulator device according to the invention permit a considerably higher rigidity than a flat plate of the same material. This effect can be even further intensified under pressure. In this way, it is possible for the hydraulic accumulator device according to the invention to be utilized as a load-bearing structure, for example in a motor vehicle. The hydraulic accumulator device may be used as a vehicle floor or as some other structural component in a motor vehicle.