Abstract:
A device with a diaphragm arrangement dividing two chambers from one another, in which the diaphragm arrangement is retained via a crimped connection, excellent restraint of the diaphragm arrangement and excellent sealing are attained with the aid of an elastomer material. The device may be a pressure valve, for instance, and serves to vary a pressure of a fuel supply system of a motor vehicle.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a 35 U.S.C. 371 application of PCT/DE01/00644, filed on Feb. 20, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention is directed to a device with a diaphragm arrangement and more particularly to such a device in which a diaphragm is secured in place between two retaining elements crimped together. 
     2. Brief Description of the Prior Art 
     European Patent EP 0 585 810 B1 shows a device for the diaphragm arrangement, having a first retaining element and a second retaining element. The diaphragm arrangement is fastened between the two retaining elements. An encompassing bead is formed onto the outer circumference of the diaphragm arrangement. The bead is located in an encompassing groove provided in the lower retaining element. In this arrangement it is disadvantageous that the encompassing bead formed onto the diaphragm arrangement increases the effort and expense of producing the diaphragm arrangement considerably, and in this diaphragm arrangement, a multi-layer construction of the diaphragm arrangement is practically impossible. Another disadvantage is that because of the encompassing groove, producing the lower retaining element requires considerably more effort and expense. 
     U.S. Pat. No. 4,825,835 shows a pressure valve with a diaphragm arrangement fastened between two retaining elements. There is an encompassing bead on the outer edge of the diaphragm arrangement. The bead rests in an encompassing groove provided on one of the two retaining elements. Because of the encompassing groove, it is very complicated to produce the retaining element that has the groove; in particular, the retaining element must be reshaped quite severely and made to assume a complicated shape. Because of the complicated shape of the retaining element, otherwise conventional materials cannot be used, and rapid wear of the stamping tool used in producing the retaining element must be feared. 
     U.S. Pat. No. 2,318,157 shows a device with a diaphragm arrangement fastened between two retaining elements. When the upper retaining element is crimped on, the outer edge of the diaphragm arrangement is bent over the outer edge of the lower retaining element. However, in this arrangement it must be feared that the diaphragm arrangement will become damaged at its fastening point during the crimping over of the retaining element. Because of the bending over of the diaphragm arrangement, diaphragms comprising multiple layers cannot be used. 
     German Published, Nonexamined Patent Application DE-OS 29 13 423 shows a device with a diaphragm arrangement fastened between two retaining elements. A sealing ring is additionally provided. Because the additional sealing ring is only very inadequately compartmentalized, subsidence and resultant leaks must be feared. Another factor is that the sealing ring cannot provide sealing directly in the region of the diaphragm fastened in place. 
     German Published, Nonexamined Patent Application DE-OS 29 24 796 shows a device with a sealing ring fastened to the crimped connection. The sealing ring is located in a sealing ring groove. Because of the requisite sealing ring groove, a diaphragm arrangement that is simple to produce cannot be used. 
     SUMMARY OF THE INVENTION 
     The device with a diaphragm arrangement according to the invention has the advantage over the prior art that at very little production effort and expense, especially when a crimped connection that is easy to manipulate is used, excellent fastening of the diaphragm arrangement and excellent sealing off of the crimped connection are attainable. 
     Another advantage is that because of the excellent restraint of the diaphragm arrangement in the region of the crimped connection, the component size of the device in the region of the crimped connection can be made rather small. In particular, only relatively slight wall thicknesses are required for the retaining elements without the need to fear impermissible deformation; or the hydraulic pressure inside the device can be chosen to be relatively high. 
     Often, the diaphragm arrangement has a surface comprising an elastomer on at least one side. The elastomer surface of the diaphragm arrangement, together with the elastomer material fastened in place in the compression chamber, has especially high frictional resistance; as a result, whenever the surface of the diaphragm arrangement, at least in the region of the elastomer material fastened in place, comprises an elastomer, an especially good, secure restraint of the diaphragm arrangement and thus an especially great and durable operating safety of the device are attained. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A preferred, especially advantages exemplary embodiment of the invention is described herein below, with reference to the drawings, in which: 
     FIG. 1 shows a longitudinal section through an exemplary embodiment; and 
     FIG. 2 shows a detail marked II in FIG.  1 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The device with a diaphragm arrangement according to the invention can be used whenever a diaphragm arrangement is fastened in place between two retaining elements crimped to one another. 
     The device is for instance a hydraulic pressure reservoir, in which a liquid is located on one side of the diaphragm arrangement, for instance, and a gas under pressure is located on the other side of the diaphragm arrangement. 
     The device can, however, also be a pressure valve, for example, in which the liquid whose hydraulic pressure is to be controlled is located on one side of the diaphragm arrangement, and atmospheric pressure, for instance, or a reference pressure is located on the other side of the diaphragm arrangement. The pressure valve is used for instance for controlling or regulating a pressure of fuel in a fuel supply system of an internal combustion engine. An Otto engine can for instance be considered as the internal combustion engine. The fuel is for instance gasoline or Diesel fuel. 
     FIG. 1 shows a longitudinal section through a preferred, especially advantageous exemplary embodiment. FIG. 2 is an enlargement of a detail marked II in FIG.  1 . 
     In all the drawings, elements that are the same or function the same are assigned the same reference numerals. Unless otherwise noted or shown in the drawing, what is said and shown for one of the drawings applies to the other drawings as well. Unless otherwise stated in the description, details of the various drawings can be combined with one another. 
     FIG. 1 shows a device embodying the invention, in the exemplary embodiment chosen, the device is a pressure valve  2 . The pressure valve  2  has a housing  4  which substantially comprises a first retaining element  6  and a second retaining element  8 . There is a diaphragm arrangement  10  inside the housing  4 . The pressure valve  2  has an inflow connection  12  and a continuing connection  14 . In its middle region, the diaphragm arrangement  10  is joined in pressure-tight fashion to a valve body  16 . The valve body  16  serves as a closing body. Above the diaphragm arrangement  10 , the pressure valve  2  has a control chamber  18 , and below the diaphragm arrangement  10 , the pressure valve  2  has a pressure chamber  20 . Depending on the pressure of the pressure medium in the inflow connection  12 , the valve body  16  lifts more or less far from a valve seat, so that at elevated pressure the pressure medium can flow out of the pressure chamber  20  into the continuing connection  14 . 
     The two retaining elements  6  and  8  are joined firmly to one another and in pressure-tight fashion via a crimped connection  21 . The first retaining element  6  has a cylindrical jacket face  6 . 1 . On the end toward the second retaining element  8 , the cylindrical jacket face  6 . 1  is bent over on the outside all the way around, so that a flange  6 . 2  extending essentially radially is formed there. The flange  6 . 2  of the first retaining element  6  ends in an encompassing end face  6 . 6 . The end face  6 . 6  points radially outward. The first retaining element  6  is preferably produced from a piece of sheet metal by being stamped out and shaped. Viewed longitudinally of the pressure valve  2 , the width of the end face  6 . 6  is approximately equal to the thickness of the sheet metal from which the first retaining element  6  is produced. The second retaining element  8  has an essentially cylindrical jacket face  8 . 1 . Toward the first retaining element  6 , the cylindrical jacket face  8 . 1  is bent over toward the outside and there forms a counterpart flange  8 . 2 . In the region of the outer circumference of the counterpart flange  8 . 2 , the retaining element  8  is bent over yet again at an encompassing bent-over point  8 . 3 . At the bent-over point  8 . 3 , the second retaining element  8  is bent over, for instance by 160° (degrees) to 180° (degrees); in the ideal case, the angle is 180°. The region, bent over by up to 180°, of the second retaining element  8  will hereinafter be called the crimped overlap  8 . 4 . The crimped overlap  8 . 4  ends radially on the inside at an encompassing end  8 . 5 . The second retaining element  8  is likewise preferably produced from a piece of sheet metal by stamping and shaping. Viewed longitudinally of the pressure valve  2 , the width of the encompassing end  8 . 5  is approximately equal to the thickness of the sheet metal from which the second retaining element  8  is produced. 
     The outer circumferential region  10 . 4  of the diaphragm arrangement  10  is fastened in place firmly and in pressure-tight fashion in the crimped connection  21  between the flange  6 . 2  and the counterpart flange  8 . 2 . 
     Viewed in the radial direction, the diaphragm arrangement  10  protrudes past the end face  6 . 6  of the first retaining element  6 . The part of the diaphragm arrangement  10  protruding radially past the end face  6 . 6  will hereinafter be called the projecting region  10 . 6 . The projecting region  10 . 6  forms a face that forms an angle of approximately 90° (degrees) with the end face  6 . 6 . Before the crimped overlap  8 . 4  is folded over onto the flange  6 . 2  of the first retaining element  6 , an elastomer material  22  is put in place at the place where the end face  6 . 6  and the region of the diaphragm arrangement  10  that projects past the end face  6 . 6  abut one another. In the folding over of the crimped overlap  8 . 4  of the second retaining element  8  onto the flange  6 . 2  of the first retaining element  6 , a compression chamber  24  is created between the end face  6 . 6  and the projecting region  10 . 6  and a compression region  8 . 6  of the second retaining element  8 , because of the elastomer material  22 . The elastomer material  22  is pressed into the compression chamber  24  or in other words squeezed in. Because even with great force the elastomer material  22  cannot be compressed arbitrarily, the compression chamber  24 , given adequate dimensioning of the elastomer material  22  placed in it, is larger than a chamber that would be created without the elastomer material  22 . The volume of the elastomer material  22  determines the size of the compression chamber  24 . 
     The lever arm between the end  8 . 5  of the crimped overlap  8 . 4  and the bent-over point  8 . 3  is substantially greater than the mean spacing between the compression region  8 . 6  and the bent-over point  8 . 3 . The result is a mechanical advantage and a stepup of the operative forces. When the two retaining elements  6  and  8  are crimped together, if the crimped overlap  8 . 4  in the region of its end  8 . 5  is pressed from above, in terms of the drawings that are part of this application, is pressed against the flange  6 . 2  of the first retaining element  6 , then, because the lever arm between the end  8 . 5  and the bent-over point  8 . 3  is substantially greater than the mean lever arm between the compression region  8 . 6  and the bent-over point  8 . 3 , the elastomer material  22  is pressed with a force that is substantially greater than the force with which the crimped overlap  8 . 4  in the region of the end  8 . 5  is pressed against the flange  6 . 2 . As a result, inside the compression chamber  24 , a very major squeezing of the elastomer material  22  takes place. Because of the major squeezing, the elastomer material  22  fills up the compression chamber  24  practically completely. 
     Because of the major squeezing of the elastomer material  22 , the elastomer material  22  presses with great force against the face of the projecting region  10 . 6  of the diaphragm arrangement  10 . The elastomer material  22  presses the diaphragm arrangement  10  at its circumference against the counterpart flange  8 . 2  of the second retaining element  8  with great force. 
     In previously known devices, when during operation a major and highly fluctuating hydraulic pressure acted on the diaphragm arrangement in the pressure chamber, in these previously known devices this often led to the diaphragm arrangement being pulled out of the crimped connection. 
     Because of the major squeezing of the elastomer material  22  and the resultant major forces, or because of the high pressure per unit of surface area between the projecting region  10 . 6  and the elastomer material  22  and facing it between the outer circumferential region  10 . 4  of the diaphragm arrangement  10  and the counterpart flange  8 . 2 , the diaphragm arrangement  10  is restrained and sealed off substantially better than in previously known devices. This makes it possible to allow especially high hydraulic pressures in the pressure chamber  20 , and even dynamically highly fluctuating pressures, even if only relatively slight wall thickness for the retaining elements  6  and  8  are employed. 
     An especially high hydraulic pressure in the pressure chamber  20 , which can be up to about ten times as high as was previously usual, does, however, lead to a slight expansion of the crimped connection  21  at the end  8 . 5  of the crimped overlap  8 . 4 . However, in the region of the bent-over point  8 . 3  of the crimped connection  21  this widening is not perceptible. Thus even at a high hydraulic pressure in the pressure chamber  20 , there is no lessening, or practically no lessening, of the squeezing of the elastomer material  22 . Thus even at very high hydraulic pressures in the pressure chamber  20 , the effect intended by the elastomer material  22  is preserved practically completely. 
     The diaphragm arrangement  10  can comprise multiple layers. In the preferred exemplary embodiment, the diaphragm arrangement  10  includes an upper layer  10 . 1 , a middle layer  10 . 2 , and a lower layer  10 . 3 . The three layers  10 . 1 ,  10 . 2 ,  10 . 3  are firmly bonded to one another, for instance by vulcanization. Since each of the three layers  10 . 1 ,  10 . 2  and  10 . 3  has a constant thickness throughout, although each layer can have a different layer from the others, the diaphragm arrangement  10  can be produced very easily, for instance by being stamped out of a larger flat plate. Stamping the diaphragm arrangement  10  out of an easily produced plate would be practically impossible if an encompassing bead were formed onto the diaphragm arrangement. 
     As the exemplary embodiment shown illustrates, the diaphragm arrangement  10  remains practically flat even in the region of the crimped connection  21 . In other words, the diaphragm arrangement  10  need not be bent over in the region of the crimped connection  21 . This allows the use of even a diaphragm arrangement  10  that because of its composition would not withstand major bending without being damaged. 
     Encompassing channels could optionally be provided on the faces toward the diaphragm arrangement  10  of the flange  6 . 2  and of the counterpart flange  8 . 2 . The channels  26  can improve the restraint of the diaphragm arrangement  10 . Because of the good hold via the elastomer material  22 , it is often possible to dispense with the channels  26 , which is why the channels  26  are not shown in solid lines in FIG. 2 but rather in dashed lines. 
     The upper layer  10 . 1  for instance comprises an elastomer. If the diaphragm arrangement  10  comprises an elastomer, at least where the elastomer material  22  presses against the diaphragm arrangement  10 , then especially high coefficients of friction occur between the diaphragm arrangement  10  and the elastomer material  22  in the compression chamber  24 , so that the restraint of the diaphragm arrangement  10  inside the crimped connection  21  can be still further improved thereby. 
     The foregoing relates to preferred exemplary embodiments of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.