Patent Publication Number: US-9410522-B2

Title: Pressure control valve

Description:
This application is a 35 U.S.C. §371 National Stage Application of PCT/EP2013/059518, filed on May 7, 2013, which claims the benefit of priority to Serial No. FR 1255351, filed on Jun. 8, 2012 in France, the disclosures of which are incorporated herein by reference in their entirety. 
     BACKGROUND 
     The disclosure relates to a pressure regulating valve. 
     EP 2333298 A1 discloses a pressure regulating valve, wherein, when the internal combustion engine is at a standstill, the pressure regulating valve is open, that is to say a connection from the high-pressure accumulator into a low-pressure line is opened up by a closing element. For this purpose, the pressure regulating valve has a magnetic actuator with a magnet core and with a magnet armature, wherein the magnetic actuator is energized in order to close the closing element by virtue of a magnet armature adjusting the closing element into its valve seat. To open the closing element, a spring element is provided which moves the magnet armature in an opening direction counter to the magnet force of the magnetic actuator, whereby the closing element is lifted from the valve seat and a hydraulic return connection between the high-pressure accumulator and the low-pressure line is opened up. The magnet armature has an armature plate which is arranged in an armature chamber formed above the magnet core. In the magnet core there is received a magnet coil with dimensionally stable contact pins, wherein the contact pins point perpendicularly from the magnet core face surface in the direction of the armature chamber. For a continuation of the contact pins in a closure cover situated above the armature chamber, leadthroughs for the contact pins are formed in the armature plate. 
     In FR 116 14 38, it is proposed that the armature chamber be hydraulically connected, via a pressure equalization duct extending through the valve housing, to a valve chamber which is connected to low pressure. In order that the two face sides of the armature plate of the magnet armature are exposed to the same pressure, a bore with a sleeve inserted therein is additionally formed in the armature plate so as to be in alignment with the pressure equalization duct, said bore serving to form a continuation of the pressure equalization duct to that face side of the armature plate which is situated opposite the armature surface. 
     SUMMARY 
     The pressure regulating valve according to the disclosure has the advantage that, through the formation of a radial extension at the further leadthrough in the residual air gap disk, improved throughflow for pressure equalization purposes is realized. The further leadthrough in the residual air gap disk is simple to produce from a manufacturing aspect and does not entail any significant additional manufacturing costs in the production of the pressure regulating valve. The pressure equalization duct has the effect that pressure fluctuations in the return line do not have any effect on the magnet armature, and that damping of the magnet armature during the opening phase of the closing element is achieved. 
     Advantageous refinements of the pressure regulating valve can be realized by means of the features of the subclaims. 
     The radial extension forms, in the residual air gap disk, a flow duct which extends substantially from the opening of the pressure equalization duct to the leadthrough formed in the armature plate. The radial extension expediently covers the opening, such that the opening of the pressure equalization duct issues into the extension. 
     The radial extension expediently has a slot-shaped form. In a first embodiment, the slot form of the radial extension is implemented with a substantially uniform width, wherein the width of the slot is formed by the diameter of the further leadthrough. In a second embodiment, the slot form of the radial extension is implemented with a decreasing width, wherein, in the direction of the opening, the width decreases from the diameter of the further leadthrough to at least approximately the diameter of the opening. 
     To make the flow duct as short as possible, the opening of the pressure equalization duct is arranged as close as possible to the leadthrough. The opening expediently lies on a line which intersects the center of the residual air gap disk and the center of the further leadthrough. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the disclosure are illustrated in the drawing and will be explained in more detail in the following description. 
       In the drawing: 
         FIG. 1  is a sectional illustration through a pressure regulating valve, 
         FIG. 2  shows a plan view of a residual air gap disk according to a first embodiment, and 
         FIG. 3  shows a plan view of a residual air gap disk according to a second embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The pressure regulating valve illustrated in  FIG. 1  is inserted into a housing  21  of a high-pressure accumulator  22  of a fuel injection device of an internal combustion engine. 
     The pressure regulating valve has a magnetic actuator and a valve element  11 , wherein the magnetic actuator  10  actuates the valve element  11 . The magnetic actuator  10  is arranged in a valve housing  12  which has a piston guide  13 , a valve piece receptacle  14  and a connector-side receptacle  15 . The valve element  11  comprises a valve piston  16  with a closing element  17  in the form of a ball. 
     In the valve piece receptacle  14  there is formed a valve piece  18  which has a valve seat  19  for the closing element  17 , wherein the closing element  17  acts on the valve seat  19 . Via a spacer ring, the valve piece  18  delimits a valve chamber  23  into which there leads a throttle bore  25  which connects the valve chamber  23  to the high-pressure accumulator  22  when the closing element  17  is open. Two lateral hydraulic connections  26 , for example, also issue into the valve chamber  23 , which lateral hydraulic connections are connected to a low-pressure line  27 , leading in turn to a return system. 
     The magnetic actuator  10  comprises a magnet core  30  with a magnet coil  32  and a magnet armature  33 , wherein the magnet coil  32  acts on the magnet armature  33  via the magnet core  30 . The magnet armature  33  has an armature plate  34  and an armature pin  35 , wherein the armature pin  35  is fixedly connected to the armature plate  34 . The armature pin  35  simultaneously forms the valve piston  16 , such that the magnet armature  33  acts on the closing element  17  via the armature pin  35 . The armature pin  35  is guided in axially displaceable fashion in the piston guide  13 , wherein the piston guide  13  leads axially through the valve housing  12 . 
     The magnet core  30  has, facing toward the armature plate  34 , a magnet core face surface  31 , also referred to as pole surface. On the armature plate  34  there is formed an armature surface  36 , wherein the armature surface  36  forms the underside or the bottom side of the armature plate  34 . Between the magnet core  30  and the armature plate  34  there is arranged a residual air gap disk  50 . Also formed into the valve housing  12 , at the magnet core face surface  31 , is a spring chamber  28  in which there is arranged a compression spring  29  which acts on the magnet armature  33  in an opening direction. 
     A closure cover  40  is inserted in hydraulically sealed fashion in the connector-side receptacle  15 . The closure cover  40  surrounds the armature plate  34  of the magnet armature  33  and forms an armature chamber  44  around the armature plate  34 . The armature plate  34  is arranged in axially movable fashion in the armature chamber  44 . 
     For electrical contacting, the magnet coil  30  is designed with a first dimensionally stable contact pin  41   a  and a second dimensionally stable contact pin  41   b , said contact pins leading substantially perpendicularly out of the magnet core face surface  34  and each being surrounded by an insulating sleeve  42   a ,  42   b.    
     The armature plate  32  has a first leadthrough  43   a  for a continuation of the first contact pin  41   a , and has a second leadthrough  43   b  for a continuation of the second contact pin  41   b . The leadthroughs  43   a ,  43   b  are designed such that a gap  45   a ,  45   b  is formed in each case between the insulating sleeves  42   a ,  42   b  and the leadthroughs  43   a ,  43   b . The function of the gap  45   a ,  45   b  will be discussed further below. The contact pins  41   a ,  41   b  are guided by means of the insulating sleeves  42   a ,  42   b  in an electrically insulating encapsulation  46  which is arranged over the closure cover  40  and where the contact pins  41   a ,  41   b  are electrically contacted. In order for the contact pins  41   a ,  41   b  to be received in sealed fashion, they are each surrounded, at the face sides of the insulating sleeves  42   a ,  42   b , by an O-ring  47  in the closure cover  40 . 
     To form a pressure-balanced pressure regulating valve, the valve chamber  23  and the armature chamber  44  are hydraulically connected to one another via a pressure equalization duct  60 . In this case, the pressure equalization duct  60  issues into the armature chamber at the magnet core face surface  31  by way of an opening  61 . 
     In order that the pressure equalization in the armature chamber  44  acts both at the underside of the armature plate  43  and at the top side of the armature plate  34 , the gaps  45   a ,  45   b  formed in the armature plate  34  between the insulating sleeves  42   a  and  42   b  and the leadthroughs  43   a ,  43   b  are utilized as passages for a throughflow of fuel for pressure equalization purposes. To increase the flow cross section for the passage, it is possible here for at least the leadthroughs  43   b  situated in the vicinity of the opening  61  to have a larger diameter or an extension. 
     Correspondingly to the leadthroughs  43   a ,  43   b  in the armature plate  44 , it is the case in  FIGS. 2 and 3  that the residual air gap disk  50  arranged between the magnet core  30  and the armature plate  43  has further leadthroughs  53   a ,  53   b  for the leadthrough of the insulating sleeves  42   a ,  42   b . At one of the two further leadthroughs  53   b , which is situated in the vicinity of the opening  61 , there is formed, for flow optimization purposes, a radial extension  54  extending in the direction of the opening  61 . The radial extension  54  thus has, lying in the radial plane, a slot-shaped form which covers the opening  61 , such that the opening  61  issues into the extension  54 . As a result, from the opening  61  to the gap  45   a  at the leadthrough  43   b , which substantially forms the passage for the fuel, there is formed a transversely running flow duct  56  which ensures that there is a hydraulic connection between the opening  61  and the gap  45   b . It is not necessary here for the radial extension  54  to extend to the spring chamber  28 . 
     The shortest possible radial extent of the flow duct  56  is attained if the opening  61  of the pressure equalization duct  60  is arranged in the vicinity of one of the leadthroughs  43   b . For the simplest solution, the position is selected by virtue of the opening  61  being situated, as per  FIGS. 2 and 3 , in alignment with a line  48  which intersects the center of the residual air gap disk  50  and the center of the further leadthrough  53   b . The proximity of the opening  61  to the insulating sleeve  42   a ,  42   b  is however limited because the pressure equalization duct  60  cannot be led through an annular magnet coil receptacle  38  in which the magnet coil  32  is cast with an insulating compound. 
     In the embodiment as per  FIG. 2 , the extension  54  is formed by a slot form with a uniform width, wherein the width of the slot is formed by the diameter of the further leadthrough  53   b.    
     In the embodiment in  FIG. 3 , the extension  54  is formed by a slot formed with a width which decreases toward the opening  61  and which, in the direction of the opening  61 , decreases from the diameter of the further leadthrough  53   b  to substantially the diameter of the opening  61 .