Abstract:
A magnetic valve includes a valve body having a valve seat which can be closed by a sealing element, at least one outlet channel which leads into a fluid chamber of the magnetic valve, receiving the sealing element at least in parts, and a flow guiding element which surrounds the sealing element at least in parts. The sealing element is operatively connected to a magnet armature arranged in a magnet armature chamber embodied on one side of the flow guiding element facing away from the fluid chamber. The valve body and the flow guiding element together form at least one connection channel producing a fluidic connection between the fluid chamber and the magnet armature chamber.

Description:
This application is a 35 U.S.C. §371 National Stage Application of PCT/EP2010/066327, filed on Oct. 28, 2010, which claims the benefit of priority to Serial No. DE 10 2009 060 293.3, filed on Dec. 23, 2009 in Germany, the disclosures of which are incorporated herein by reference in their entirety. 
     BACKGROUND 
     The disclosure relates to a solenoid valve with a valve body, the valve body having provided in it a valve seat closable by means of a sealing element, at least one outlet duct issuing into a fluid space, receiving the sealing element at least in regions, of the solenoid valve, and a flow guide element surrounding the sealing element at least in regions, the sealing element being operatively connected to a magnet armature arranged in a magnet armature space formed on a side of the flow guide element which faces away from the fluid space. The disclosure relates, furthermore, to a driver assistance device. 
     Solenoid valves of the type initially mentioned are known from the prior art. Solenoid valves of this type, for example currentlessly closed 2/2-way solenoid valves or else currentlessly closed 2/2-way solenoid valves, can be used in ABS, TCS or ESP systems. The solenoid valves have a valve seat which is closable by means of a sealing element. For this purpose, the sealing element is displaceable at least between a closing position and a releasing position. In the closing position, the sealing element is arranged in such a way that it covers the valve seat and therefore closes it. In the releasing position, the sealing element is, for example, spaced apart from the valve seat, so that fluid can pass through the valve seat. In the closing position, the solenoid valve is impermeable to the fluid, whereas, in the releasing position, this fluid can flow through the solenoid valve. The sealing element is arranged at least in regions in the fluid space of the solenoid valve. The valve seat may also be present in a wall of the fluid space. Moreover, the at least one outlet duct issues into the fluid space, and there may be a permanent fluid connection between the fluid space and the outlet duct. Fluid can be supplied to the solenoid valve via an inlet duct, this fluid being conveyed toward the valve seat via the inlet duct. When the sealing element is in the releasing position, the fluid can pass through the valve seat into the fluid space and subsequently be discharged from this via the outlet duct. 
     In the releasing position, the sealing element is usually arranged above the valve seat, so that the fluid flowing through the valve seat flows onto said sealing element or onto a magnet armature connected to it. Moreover, the flow direction of the inflowing fluid often points away from the outlet duct, so that the fluid is first braked in the fluid space before it can flow into the outlet duct. In this case, it may also happen that the fluid passes into regions between the magnet armature and a housing of the solenoid valve. Both the flow of the inflowing fluid onto the sealing element and/or onto the magnet armature and the fluid penetrating between the magnet armature and housing influence the displaceability of the sealing element, since the fluid applies an additional axial force to the sealing element or to the magnet armature connected to the sealing element. This may sometimes adversely affect the actuation quality of the solenoid valve. This is because this additional force influences the equilibrium of forces between a restoring force of a spring element and a magnetic force which serves for displacing the sealing element and which acts on the magnet armature, and a fluid pressure force which is taken into account in the design of the solenoid valve. This is the case particularly in solenoid valves in which a mouth of the outlet duct in the fluid space is arranged next to the valve seat, so that the inflow of the fluid through the valve seat and outflow through the outlet duct take place in opposite directions. 
     It would basically be advantageous if, instead of the additional forces acting in the axial direction upon the sealing element or magnet armature, only rotationally symmetrical radial forces were to occur, because these have no influence upon the axial equilibrium of forces. For this reason, a flow guide element may be provided which, for example, has a flow guide surface, by means of which inflowing fluid is deflected in the direction of the outlet duct or is conveyed toward the latter. The flow guide surface may in this case be curved at least in regions, advantageously in the direction of the outlet duct. The flow guide element in this case separates the magnet armature space from a fluid space of the solenoid valve in which the valve seat is arranged. The magnet armature, to which the sealing element is operatively connected, is arranged in the magnet armature space. By virtue of this operative connection, the sealing element can be displaced by means of the magnet armature, this being provided at least between the closing position and the releasing position. 
     A solenoid valve of this type is known, for example, from DE 198 02 464 A1. This shows a hydraulically magnet-actuated valve with a guide body for pressure medium which is arranged in the housing of the solenoid valve and which is penetrated by a closing body and separates an annular duct connected conductively to a valve seat pressure medium and having at least one circumferential outlet port of the valve housing from a space containing actuating means of the valve. In this case, the guide body is to be supported on the valve body by bearing against the end face of the latter and is to have guide ducts which overlap with their contour the mouth-side valve seat and which issue on the outflow side into the annular duct. In known solenoid valves, pressure compensation or fluid exchange between the fluid space and magnet armature space is brought about by means of an orifice of the flow guide element, in which orifice the sealing element is arranged or guided at least in regions. 
     SUMMARY 
     By contrast, the advantage of the solenoid valve having the features described herein is that an improvement in the actuability of the solenoid valve is achieved. For this purpose, according to the disclosure, there is provision whereby the valve body and flow guide element jointly form at least one connecting duct making a fluid connection between the fluid space and the magnet armature space. Fluid can flow via the connecting duct between the fluid space and magnet armature space, so that pressure compensation between these two spaces is implemented. Thus, for example, it cannot happen that a pressure which counteracts a displacement of the magnet armature is built up within the magnet armature space as a result of displacement of the magnet armature. Thus, the actuability of the solenoid valve can be markedly improved by means of the fluid connection via the connecting duct. According to the disclosure, there is provision whereby the connecting duct is formed jointly by the valve body and flow guide element. For this purpose, for example, the connecting duct may be surrounded, on the one hand, by regions of the valve body and, on the other hand, by regions of the flow guide element. The term “connecting duct” is to be understood, above all, as not meaning any duct which is formed solely in the valve body or in the flow guide element. The flow guide element prevents the situation where fluid flowing into the fluid space through the valve seat can come directly into contact with, and thus act with an undesirable force upon, the magnet armature or regions of the valve body which are arranged in the magnet armature space. For this purpose, the flow guide element separates the magnet armature space from the fluid space, so that the fluid applies the force solely to the flow guide element. In order to prevent the flow guide element from being displaced in the direction of the magnet armature by this force, the flow guide element is held non-displaceably, that is to say fixed in place, inside the solenoid valve. For this purpose, said flow guide element may, for example, be fastened in the fluid space in a positive, nonpositive and/or materially integral manner. The flow guide element is preferably pressed into the valve body in such a way that a nonpositive connection between the flow guide element and guide body is obtained. 
     In a development of the disclosure, the connecting duct is present between an inner wall of the valve body and an outer wall of the flow guide element. The flow guide element is therefore to be arranged in the valve body in such a way that the connecting duct is formed between these two elements. For example, the connecting duct may be present at least in regions as an annular duct if both the valve body and the flow guide element have an essentially circular cross section. In order to form the connecting duct, of course, the valve body and/or the flow guide element must deviate at least in regions from this circular cross section. Alternatively, it is also possible to design the valve body and flow guide element so as to be essentially circular and to space them apart by means of struts which may be present either on the valve body or on the flow guide element. 
     In a development of the disclosure, at least one radial duct is formed in the valve body and makes a fluid connection between the outlet duct and the connecting duct. Whereas the outlet duct is present in the valve body, the connecting duct is formed jointly by the valve body and flow guide element. In order to make a fluid connection between the outlet duct and connecting duct and therefore also the fluid space and magnet armature space, the radial duct is provided which is formed in the valve body. A radial duct is to be understood in this context as meaning a duct which is suitable for guiding fluid essentially in the radial direction, a main flow direction of the fluid having at least one radial component. The radial duct is therefore intended for making a fluid connection from an outlet duct provided further inward with respect to a longitudinal axis of the solenoid valve to a connecting duct located further outward with respect to the longitudinal axis. The radial duct is present, for example, as a depression or recess of the valve body. 
     In a development of the disclosure, the flow guide element lies on a bottom of the fluid space, and the radial duct passes through the bearing surface of the flow guide element. If the flow guide element is arranged entirely on the bottom of the fluid space or provided so as to lie on this, there is no fluid connection between the fluid space and regions arranged radially outside the flow guide element. The radial duct is consequently provided. This passes through the bearing surface of the flow element at the bottom of the fluid space in such a way that the fluid connection between the fluid space or the outlet duct and regions, in particular the connecting duct, arranged radially outside the flow guide element is made. The bearing surface of the flow guide element is therefore not entire, but is pierced by the radial duct. 
     In a development of the disclosure, the valve body has in its inner wall and/or the flow guide element has in its outer wall a recess which coforms the connecting duct. The recess is intended to space the valve body and flow guide element apart from one another in such a way that fluid can flow through between them and therefore the connecting duct is formed. In this case, the recess may have basically any desired extent in the circumferential direction of the solenoid valve. Advantageously, a plurality of recesses are provided which are distributed uniformly over the circumference. An even number of recesses is preferably formed, in each case two of the recesses lying diametrically opposite one another. The recess passes through the inner wall or the outer wall, so that an open-edged depression is obtained. Furthermore, the recess affords a continuous run of the inner wall or outer wall, and these deviate only in regions from a specific shape, for example a circular shape. The connecting duct can thereby be formed between the inner wall and the outer wall. 
     In a development of the disclosure, the connecting duct and/or the radial duct are at least in regions round, in particular circularly round, in cross section. This applies especially when an inner space of the valve body, that is to say the fluid space, and the flow guide element are likewise essentially round or circularly round. In this case, the connecting duct may be present at least in regions as an annular duct, in which case it is delimited on the outside by the inner wall of the valve body and on the inside by the outer wall of the flow guide element. The radial duct, too, may be designed at least in regions to be round. For example, the radial duct is present solely as an axially introduced bore of the valve body. Especially simple production of the radial duct is thus possible. The diameter of the bore is in this case selected in such a way that the fluid connection between the outlet duct and the connecting duct is made. 
     In a development of the disclosure, the flow guide element is composed of metal or of plastic. The flow guide element may basically be produced from any desired material. Advantageously, however, metal or plastic is provided. The solenoid valve can thus be designed with very high fatigue strength. 
     In a development of the disclosure, the flow guide element is designed as a stamped and bent part or as an injection molding. Particularly when the flow guide element is composed of metal, it may be advantageous to produce it as a stamped and bent part. By contrast, a flow guide element composed of plastic can be implemented especially simply as an injection molding. 
     In a development of the disclosure, an alignment means for aligning the flow guide element in the fluid space in the circumferential direction is provided. The alignment means is necessary especially when the connecting duct is formed by the recess formed in the outer wall of the flow guide element. In this case, it is necessary to align the connecting duct with regard to the radial duct formed in the valve body, in order to make the fluid connection between the outlet duct and connecting duct. The flow guide element must therefore be aligned in the fluid space in terms of the circumferential direction. For this purpose, the alignment means is provided. The alignment means may be composed, for example, of a projection which is formed either on the valve body or on the flow guide element and co-operates with a recess of the other element in each case, in order to implement the alignment of the flow guide element. 
     The disclosure relates, furthermore, to a driver assistance device, in particular ABS, TCS or ESP device, with at least one solenoid valve, in particular according to the above statements, having a valve body, the valve body having provided in it a valve seat closable by means of a sealing element, at least one outlet duct issuing into a fluid space, receiving the sealing element at least in regions, of the solenoid valve, and a flow guide element surrounding the sealing element at least in regions, the sealing element being operatively connected to a magnet armature arranged in a magnet armature space formed on a side of the flow guide element which faces away from the fluid space. In this case, there is provision whereby the valve body and flow guide element jointly form at least one connecting duct making a fluid connection between the fluid space and the magnet armature space. 
    
    
     
       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 to the disclosure occurring. In the drawing: 
         FIG. 1  shows a cross section through a region of a first embodiment of a solenoid valve, 
         FIG. 2  shows an alternative view of the solenoid valve known from  FIG. 1 , 
         FIG. 3  shows a valve body of the solenoid valve known from  FIG. 1 , 
         FIG. 4  shows a flow guide element of the solenoid valve known from  FIG. 1 , 
         FIG. 5  shows a cross section through a region of a second embodiment of the solenoid valve, 
         FIG. 6  shows an alternative view of the solenoid valve known from  FIG. 5 , 
         FIG. 7  shows the valve body of the solenoid valve known from  FIG. 5 , and 
         FIG. 8  shows the flow guide element of the solenoid valve known from  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a cross section through a region of a solenoid valve  1  which is arranged in an external device  2  which is merely indicated here. The solenoid valve  1  has a valve body  3  and a housing  4 , a magnet armature  5  being mounted axially movably in the housing  4 . A riser duct  6  is formed in the valve body  3  and is flow-connected to at least one inlet duct  7 . Fluid can be supplied to the solenoid valve  1  through the inlet duct  7 . The riser duct  6  is in this case formed in the axial direction (with regard to a longitudinal axis  8  of the solenoid valve  1 ). By contrast, the inlet ducts  7  emanate in the radial direction from said riser duct and issue into a surface area  9  of the valve body  3  or of the solenoid valve  1 . 
     In order to form the riser duct  6 , a bore is first introduced into the valve body  3  in the axial direction starting from one end face  10  of the solenoid valve  1  or of the valve body  3 . This bore is subsequently closed below the issue of the inlet ducts  7  into the riser duct  6  by means of a closing element  11 , so that the fluid which passes into the riser duct  6  through the inlet ducts  7  flows in the direction of a valve seat  12 . The valve seat  12  is in this case formed in the valve body  3 . Furthermore, the valve body  3  has at least one outlet duct  13 . In the present embodiment, both four inlet ducts  7  and four outlet ducts  13  are provided, only one inlet duct  7  and two outlet ducts  13  being illustrated. 
     A sealing element  14  can be displaced in the axial direction of the solenoid valve  1  by means of the magnet armature  5 . In this case, in a closing position (as shown in  FIG. 1 ) the sealing element  14  can co-operate with the valve seat  12  in such a way that a fluid connection between inlet ducts  7  and outlet ducts  13  is broken. When the sealing element  14  is displaced in the axial direction by means of the magnet armature  5 , it is then arranged above the valve seat  12 , so that fluid can flow through the valve seat  12 , whereby the fluid connection between inlet ducts  7  and outlet ducts is made. The sealing element  14  is in this case arranged at least in regions in a fluid space  15 . The fluid space  15  is formed by the valve body  3  and a flow guide element  16 , the flow guide element  16  being arranged in the valve body  3  in such a way that both the fluid space  15  and a magnet armature space  17  are present. Both the sealing element  14  and the magnet armature  5  are arranged at least in regions in the magnet armature space  17 . The magnet armature space  17  is in this case located on that side of the flow guide element  16  which faces away from the fluid space  15 . 
     The flow guide element  16  has a central recess  18  which is pierced by the sealing element  14 . The flow guide element  16  is intended for improving the flow of the fluid in the fluid space  15  in that fluid flowing into the fluid space  15  through the valve seat  12  is deflected preferably in the direction of mouths  19  of the outlet ducts  13  issuing into the fluid space  15 . The flow occurring when the sealing element  14  is displaced out of the closing position is indicated by the arrows  20 . In particular, however, the flow guide element  16  is intended for preventing the situation where the fluid flowing in through the valve seat  12  applies an undesirable force to the magnet armature  5  or to the sealing element  14 . For this purpose, it prevents the situation where the fluid flowing into the fluid space  15  may come directly into contact with the magnet armature  5  or with regions of the sealing element  14  which are arranged in the magnet armature space  17 . 
     In the embodiment of the solenoid valve  1  illustrated in  FIG. 1 , the flow guide element  16  surrounds the sealing element  14  completely in the circumferential direction. This means, however, that there is in the first place a fluid connection between the fluid space  15  and magnet armature space  17  through the recess  18  only. Consequently, during displacement of the magnet armature  5  or of the sealing element  14  in the axial direction, different pressures may occur in the fluid space  15  and in the magnet armature space  17  or a pressure which counteracts displacement of the magnet armature  5  may be built up in the magnet armature space  17 . For this reason, at least one connecting duct  21  is to be provided which improves the fluid connection from the fluid space  15  and magnet armature space  17  and thus prevents the build-up of the above-described pressure in the magnet armature space  17 . The actuability of the solenoid valve  1  is thereby markedly improved. 
     The connecting duct  21  is to be formed jointly by the valve body  3  and flow guide element  16 . For this purpose, as shown in  FIG. 1 , it is present between an inner wall  22  of the valve body  3  and an outer wall  22  of the flow guide element  16 . The resulting fluid connection, together with the possible flow directions of the fluid, is indicated by the double arrow  24 . In the embodiment present here, four connecting ducts  21  are provided which are distributed uniformly over the circumference of the valve body  3 , although only two of the connecting ducts  21  are illustrated. Each connecting duct  21  is assigned a radial duct  25  which is formed in the valve body  3 . Via these, fluid connection is made between the outlet duct  13  and the respective connecting duct  21 . 
     The flow occurring in the radial duct  25  is identified, together with the possible flow directions, by the double arrow  26 . In general, there is provision for the flow guide element  16  to lie on a bottom  27  of the valve body  3 . In order to form the radial ducts  25 , therefore, there is provision for passing through a bearing surface  28  of the flow guide element  16  on the bottom  27 . To form the connecting ducts  21 , in the embodiment of the solenoid valve  1  which is illustrated in  FIG. 1  a recess  29  is formed in the inner wall  22  of the valve body  3 . In the region of the recess  29 , the outer wall  23  of the flow guide element  16  is spaced apart from the inner wall  22  of the valve body  3 , so that the connecting duct  21  is formed at this location. In further regions, the inner wall  22  and the outer wall  23  bear one against the other in order thereby to implement a nonpositive hold of the flow guide element  16  in the valve body  3 . 
       FIG. 2  shows an alternative view of the solenoid valve  1  known from  FIG. 1 . Only the valve body  3  and the flow guide element  16  are illustrated here. The valve body  3  and the flow guide element  16  are designed according to the above statements, and therefore reference might to that extent be made to these. It can be seen clearly in  FIG. 2  that the connecting ducts  21  between the inner wall  22  and the outer wall  23  are formed jointly by the valve body  3  and flow guide element  16 , for which purpose the recesses  29  are provided in the valve body  3 . 
       FIGS. 3 and 4  show isometric views of the valve body  3  and of the flow guide element  16  respectively. Reference may also be made in this regard to the above statements. It becomes clear from  FIG. 4  that the flow guide element  16  has a continuous circularly round outer circumference, while the recesses  29  are formed in the valve body  3 , as can be seen in  FIG. 3 . 
       FIG. 5  shows a cross section through a region of a second embodiment of the solenoid valve  1 . This embodiment basically corresponds to that already explained by means of  FIG. 1 . Reference may be made to that extent to the above statements. The embodiment illustrated in  FIG. 5  differs from that described above only in that the recesses  29  are now not formed in the valve body  3 , but instead in the flow guide element  16  or in its outer wall  23 . The outer wall  23  of the flow guide element  16  therefore deviates from a circularly round run. By contrast, the inner wall  22  of the valve body  3  runs continuously and without any deviation from the circular shape at least in the region co-operating with the outer wall  23 . Here too, therefore, the connecting ducts  21  are formed by the co-operation of the inner wall  22  and outer wall  23 , although the recesses  29  necessary for this purpose are implemented in the valve body  3 . 
     In order to achieve alignment of the connecting ducts  21  and radial ducts  25 , it is advantageous if an alignment means, not illustrated here, is provided. This may be composed, for example, of a projection formed on the flow guide element  16  and of a counterelement receiving the projection. The counterelement is in this case provided on the valve body  3 . Conversely, it is, of course, also possible to arrange the projection on the valve body  3  and the counterelement on the flow guide element  16 . 
     The following  FIGS. 6 ,  7  and  8  illustrate the design of the embodiment of the solenoid valve  1  which was described by means of  FIG. 5 . Reference may therefore be made to the above statements.