Abstract:
A solenoid valve is disclosed that includes at least one chamber which can be filled with a fluid and which is provided in a housing of the solenoid valve, a closing piston which can be displaced by an actuation device and a spring element which can act against the actuation device. An annular element which divides the chamber into a first and a second sub-chamber is provided, said annular element being at least partially, in particular completely engaged in the axial direction by a closing piston of the solenoid valve arranged in a guide opening of the annular element and comprises at least one fluid passage recess which is different from the guide opening.

Description:
This application is a 35 U.S.C. §371 National Stage Application of PCT/EP2010/066451, filed on Oct. 29, 2010, which claims the benefit of priority to Serial No. DE 10 2009 055 339.8, filed on Dec. 28, 2009 in Germany, the disclosures of which are incorporated herein by reference in their entirety. 
     The disclosure relates to a solenoid valve with at least one fluid-fillable chamber provided in a housing of the solenoid valve, with a closing piston displaceable by means of an actuation device, and with a spring element counteracting the actuation device. 
     BACKGROUND 
     Solenoid valves of the type initially mentioned are known from the prior art. They are used, for example, in driver assistance devices, such as, for example, ABS, TCS and ESP systems and the like. Such a solenoid valve may in this case be designed as a 2/2 way solenoid valve. This is also designated as a straight-way valve. Solenoid valves serve, above all, for metering a fluid. For this purpose, they have an actuation device, by means of which a through orifice of the solenoid valve can be at least partially opened or closed. The actuation device in this case comprises an electromagnet, that is to say the solenoid valve can be actuated electrically. A fluid connection between an inlet and an outlet of the solenoid valve can be made via the through orifice. In this case, in particular, there may be provision whereby the through orifice is closed in a position of rest of the solenoid valve and is opened by voltage being applied to the electromagnet. Alternatively, however, a reversed version is also possible, in which the through orifice is open in the position of rest of the solenoid valve and is closed only by the actuation device being actuated, that is to say, for example, by voltage being applied to the electromagnet. 
     Usually, there is provision for the solenoid valve to have a spring element counteracting the electromagnet. This spring element is arranged in the fluid-fillable chamber. It ensures that the solenoid valve remains in its position of rest or is returned to this when the actuation device is not activated. In this case, the spring element, for example a helical spring, acts, on the one hand, upon the actuation device and, on the other hand, for example, upon a sealing body with the restoring force. The sealing body is intended to cooperate with a closing piston displaceable by means of the actuation device, in order to close sealingly or to release at least partially the through orifice. For this purpose, the solenoid valve inlet or outlet, which can be closed by means of the closing piston, is arranged in the sealing body. In this case, on the one hand, the spring element extends through the entire chamber in order, on the one hand, to cooperate with the actuation device and, on the other hand, to be supported on the sealing body. The sealing body is thus acted upon with a force which can sometimes cause deformations of the sealing body which are possibly detrimental to the sealing action of the latter. The sealing body is also often composed of an elastic material, and it therefore cannot form a defined bearing surface for the spring element. On the other hand, the spring element is exposed to fluid forces which are caused by the inflow of fluid through the chamber. The flow connection between the inlet and the outlet of the solenoid valve is therefore made, in particular, via the chamber. 
     SUMMARY 
     By contrast, the advantage of the solenoid valve having the features mentioned herein is that the spring element is not exposed to any undesirable fluid forces and the sealing body is not acted upon by the closing piston with a force which deforms it. This is achieved, according to the disclosure, by means of a ring element which subdivides the chamber into a first and a second subchamber, is penetrated at least partially, in particular completely, in the axial direction by the closing piston, arranged in a guide orifice in the ring element, of the solenoid valve and has at least one fluid passage recess different from the guide orifice. The ring element is therefore arranged in the chamber or between the first and the second subchamber. In this case, both the first and the second subchamber can be filled with fluid in the same way as the entire chamber. Advantageously, the inlet and outlet are assigned to only one of the subchambers, while only the spring element, the actuation device and a region of the closing piston are provided in the other of the subchambers. The ring element may be interrupted in the circumferential direction, that is to say does not have to pass through the chamber completely, as seen in the circumferential direction. The ring element has the guide orifice in which the closing piston of the solenoid valve is arranged axially displaceably. 
     In this case, the closing piston penetrates through the ring element at least partially in the axial direction. Complete penetration is preferably provided. The guide orifice is adapted to the closing piston, that is to say has a similar diameter to the latter, so that the closing piston, although guided reliably in the ring element, is nevertheless displaceable in the axial direction. This also means, however, that the first and the second subchamber would be separated essentially fluidically from one another, that is to say no fluid exchange could take place between them. For this reason, the fluid passage recess is provided, which is different from the guide orifice, but in this case does not necessarily have to be spaced apart from the latter. The fluid passage recess allows fluid exchange between the first and the second subchamber. The function of the solenoid valve is thereby not impaired by the ring element. The ring element surrounds the closing piston at least in regions. It bears at least in regions against an inner wall of the housing or is supported on said inner wall or is held/fastened there. The ring element makes it possible to support the spring element securely, so that a reliable return or hold of the closing piston in its position of rest is implemented. In addition, what can thereby be achieved is that the spring element is not acted upon by undesirable fluid forces which occur, for example, when the fluid flows through the chamber. 
     In a development of features of the disclosure, the ring element is designed as a tension sleeve or clamping sleeve. Both the tension sleeve and the clamping sleeve are held by clamping in the chamber or on the inner wall of the housing. They therefore have the same dimensions as, preferably larger dimensions than the chamber in order to implement this clamping connection. The tension sleeve in this case has an axial slot which makes it possible to introduce it into the chamber in a simple way. By contrast, the clamping sleeve is designed without the axial slot, that is to say surrounds the closing piston completely in the circumferential direction. 
     In a development of features of the disclosure, the fluid passage recess is designed as a fluid passage pocket and/or penetrates through a basic body of the ring element at least partially in the radial direction. The fluid passage pocket is in this case designed in such a way that it is set back with respect to a circumferential surface of the ring element, that is to say the wall thickness of the ring element is reduced in the region of the fluid passage pocket. There may likewise be provision for the fluid passage recess to penetrate completely through the ring element in the radial direction. This is the case, for example, with regard to the tension sleeve in which the axial slot forms the fluid passage recess. The fluid passage recess makes the fluid connection between the first and the second subchamber independently of the guide orifice. 
     In a development of features of the disclosure, the fluid passage pocket is formed in an outer circumferential surface and/or inner circumferential surface of the ring element. If the fluid passage pocket is formed in the outer circumferential surface, it extends radially inward, and if it is provided in the inner circumferential surface it extends radially outward. The fluid passage pocket extends only partially over the outer circumferential surface or the inner circumferential surface. 
     In a development of features of the disclosure, the fluid passage pocket is channel-shaped, groove-shaped and/or notch-shaped. Basically, the fluid passage pocket may be shaped in any desired way. However, a channel, groove or notch shape is preferred. The channel shape in this case has a cross section which is round or oval at least in regions, the groove shape has an essentially rectangular cross section and the notch shape has an essentially triangular cross section. 
     In a development of features of the disclosure, at least one supporting web is formed next to the fluid passage pocket and bears against an inner wall of the housing. The supporting web ensures connection to the housing or to the inner wall of the housing and consequently the fastening of the ring element. The supporting web may have any desired width in the circumferential direction and be designed to be continuous or else interrupted in the axial direction. If a plurality of fluid passage pockets are provided, the supporting web is arranged in each case between these. In order to make as good a fluid connection as possible between the first and the second subchamber, it is advantageous if the overall cross section of the fluid passage pockets is larger than the overall cross section which is occupied by the at least one supporting web. 
     In a development of features of the disclosure, the fluid passage recess is provided as a fluid passage bore in the ring element. The fluid passage bore in this case penetrates completely through the ring element in the axial direction in order to make the fluid connection between the first and the second subchamber. In this case, the fluid passage bore may have a constant diameter or alternatively also different diameter in the axial direction. The design of the fluid passage recess or of the fluid passage bore thus makes it possible to implement a throttle between the first and the second subchamber. If a plurality of fluid passage bores are provided on the ring element, these may have identical or different diameters. 
     In a development of features of the disclosure, the fluid passage recess runs straight, obliquely and/or helically in the axial direction. The throughflow behavior of the fluid passage recess can be set by means of its run. The straight run of the fluid passage recess is preferred, but alternatively an oblique or helical run may also be provided. 
     In a development of features of the disclosure, a plurality of fluid passage recesses are provided so as to be distributed, in particular uniformly, over the circumference of the ring element. In order to achieve as good a flow connection as possible between the first and the second subchamber, a plurality of fluid passage recesses are preferably provided. These may be provided on the ring element in any desired way, but the arrangement distributed over the circumference is preferred, since an especially good throughflow with a low pressure loss is thereby achieved. This applies particularly when the fluid passage recesses are distributed uniformly. 
     In a development of features of the disclosure, the ring element possesses a supporting surface for the spring element of the solenoid valve. As already stated above, the ring element preferably serves for supporting the spring element. For this purpose, the supporting surface is provided which can be adapted to the spring element. In particular, the supporting surface may have means for fastening and/or guiding the spring element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure is explained in more detail below by means of the exemplary embodiments illustrated in the drawing, without any restriction of the disclosure occurring. In the drawing: 
         FIG. 1  shows a cross section of a solenoid valve with a ring element arranged in a chamber, 
         FIG. 2  shows a first embodiment of the ring element, and 
         FIG. 3  shows a second embodiment of the ring element. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a solenoid valve  1  with a housing  2  which is composed of a jacket  3  continuous at least in regions and of at least one structural element  4 . Provided in the housing  2  of the solenoid valve  1  is a chamber  5  which is subdivided by a ring element  6  into a first subchamber  7  and a second subchamber  8 . The solenoid valve  1  has, furthermore, an actuation device  9  which has at least one electromagnet (not illustrated here). By means of the actuation device  9 , a closing piston  10  can be displaced in the axial direction with respect to a longitudinal axis  11  of the solenoid valve  1 . 
     The solenoid valve  1  has an inlet  12  and an outlet  13  for fluid. A plurality of inlets  12  may also be provided, as illustrated in  FIG. 1 . The inlet  12  is fluid-connected permanently to the second subchamber  8 . A fluid connection between the second subchamber  8  and the outlet  13  or between the inlet  12  and the outlet  13  can be closed or at least partially opened by means of the solenoid valve  1 . For this purpose, the closing piston  10  cooperates with a sealing body  14 . In a closing position, the closing piston  10  lies on the sealing body  14  in such a way that the fluid connection is interrupted. In an open position, by contrast, the closing piston  10  is displaced upward in the axial direction so that the fluid connection is released. In the embodiment of the solenoid valve  1  illustrated here, the open position corresponds to a position of rest of the closing piston  10 . This means that the fluid connection between the inlet  12  and outlet  13  is present until the closing piston  10  is displaced in the axial direction by means of the actuation device  9 , so that said closing piston moves towards the sealing body  14  and cooperates with the latter to interrupt the fluid connection. For this purpose, the first subchamber  7  has arranged in it a spring element  15  which is designed as a compression spring and which, on the one hand, exerts a restoring force upon the actuation device  9  and, on the other hand, is supported on the ring element  6 . For this purpose, the ring element  6  has a supporting surface  16 . Alternatively, the spring element  15  may also be in the form of a tension spring. In this case, the closing position is the position of rest. 
     By means of the supporting surface  16 , on the one hand, reliable support of the spring element  15  is ensured and, on the other hand, the spring element  15  is in a region in which it is not acted upon by undesirable fluid forces. These fluid forces occur, for example, when the fluid flows through the solenoid valve  1  when the fluid connection between the inlet  12  and the outlet  13  is released. The closing piston  10  is mounted for axial guidance in a guide orifice  17  of the ring element  6 . In this case, the ring element  6  surrounds the closing piston  10  at least in regions in the circumferential direction. 
     The closing piston  10  penetrates through the ring element at least partially, in particular completely, in the axial direction, as illustrated in  FIG. 1 . It has in this case a fluid passage recess  18  which cannot be seen here and which allows fluid connection between the first subchamber  7  and the second subchamber  8 . This fluid connection is provided in order to allow reliable fluid exchange between the two subchambers  7  and  8  and consequently to ensure the displaceability of the closing piston  10  by means of the actuation device  9 . If the fluid connection were not sufficient, a pressure would build up in the first subchamber  7  upon actuation of the actuation device  9  and would counteract the displacement of the closing piston  10 . This is prevented by the fluid passage recesses  18 . The fluid connection may also be implemented at least partially via the guide orifice  17 . However, in order to enable the closing piston  10  to be guided reliably, it has at least similar dimensions to said guide orifice. For this reason, it is necessary to provide the passage recess  18  which is different from the guide orifice  17 . 
       FIG. 2  shows a first embodiment of the ring element  6 . In this embodiment, the ring element  6  is designed as a tension sleeve  19  which is round, particularly circular, in cross section, which means that an axial slot  21  is provided in a basic body  20  of the ring element  6 . This axial slot  21  makes it possible to reduce the size of the ring element  6  in the radial direction when it is being mounted in the housing  2  of the solenoid valve  1 . In this case, however, the axial slot  21  serves at the same time as a fluid passage recess  18 . Moreover, the guide orifice  17  is provided in the basic body  20 . In the embodiment present here, the fluid passage recess  18  therefore penetrates completely through the basic body  20  in the radial direction. In this case, said fluid passage recess issues both into an outer circumferential surface  22  and into an inner circumferential surface  23  of the ring element  6  and consequently into the guide orifice  17 . The ring element  6  bears with the outer circumferential surface  22  against an inner wall  24  (see  FIG. 1 ) of the housing  2  and is thus held in the chamber  5  such that it separates the two subchambers  7  and  8  at least partially from one another. Since the guide orifice  17  is filled essentially by the closing piston  10 , the flow connection between the subchambers  7  and  8  is made via the axial slot  21  or the fluid passage recess  18 . 
     A further embodiment of the ring element  6  is shown in  FIG. 3 . In this case, it is designed again as a tension sleeve  19 , that is to say has the axial slot  21  which serves as a fluid passage recess  18 . Reference may be made thus far to the above description. Additionally, however, the ring element  6  has four further fluid passage recesses  26  which are formed in the outer circumferential surface  22 . Alternatively, an arrangement of the fluid passage recesses  25  in the inner circumferential surface  23  may also be provided. The fluid passage recesses  25  are designed as fluid passage pockets  26 . This means that they are set back in the radial direction with respect to the outer circumferential surface  22 , so that a depression is formed in the basic body  20 . The fluid passage pockets  26  are at least in regions of channel-shaped design. 
     Between the fluid passage pockets  26 , supporting webs  27  are provided, via which the ring element  6  is connected to the inner wall  24  of the chamber  5  or of the housing  2  in order to hold or to fasten the ring element  6 . The clamping connection of the tension sleeve  19  can thus be made via the supporting webs  27 . Both the supporting webs  27  and the fluid passage pockets  26  are distributed uniformly over the circumference of the ring element  6 . A reliable flow connection between the subchambers  7  and  8  is thereby made. In the exemplary embodiment illustrated, the fluid passage pockets  26  run in the axial direction straight through the ring element  6  or its outer circumferential surface  22 . Alternatively, however, there may also be provision whereby the fluid passage pockets  26  have an oblique or helical run. 
     Additionally or alternatively, the fluid passage recesses  25  may be present as fluid passage bores (not illustrated). These are bores which issue into end faces  28  of the ring element  6  and in this case run through the basic body  20 . 
     As compared with solenoid valves known from the prior art, the solenoid valve  1  has the advantage that the supporting surface  16  for the spring element  15  is provided and, moreover, the spring element  15  is arranged in a region of the solenoid valve  1  (to be precise, in the first subchamber  7 ), in which it is not impaired by undesirable fluid forces. This would be the case, for example, if the ring element  6  were not present and the spring element  15  would therefore have to be supported on the sealing body  14 . The spring element  15  would then be arranged in the fluid connection between the inlet  12  and the outlet  13 , so that the fluid flow through the solenoid valve  1  could influence the spring element  15  and its restoring force upon the actuation device  9  or the closing piston  10 . This is avoided by the arrangement of the ring element  6 , so that the solenoid valve  1  described above operates extremely reliably.