Abstract:
The invention relates to a device ( 10 ) for pressure regulation, having a housing ( 11 ) and a closing body ( 12 ) received axially movably therein, wherein the housing ( 11 ) has at least one pressure medium inlet ( 21 ) and one pressure medium outlet ( 22 ), and the closing body ( 12 ) is prestressed by a helical spring ( 14 ) against a valve seat ( 11′ ) in the housing, and at least one compensation means for the helical spring ( 14 ) is provided. The invention provides that as the compensation means, a compensation element ( 15 ) disposed between the closing body ( 12 ) and an end, oriented toward the closing body ( 12 ), of the helical spring ( 14 ) is provided, which is braced resiliently in the radial direction on the inner wall of the housing ( 11 ) and, with its central region ( 15 ′), is in preferably frictional-engagement contact with the closing body ( 12 ). The central region ( 15′ ) of the compensation element ( 15 ) is embodied as dome-shaped, and radially protruding spring arms ( 15 ″) are disposed peripherally to the central region ( 15′ ) of the compensation element ( 15 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a 35 USC 371 application of PCT/DE 01/01019 filed on Mar. 16, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention is directed to an improved device for pressure regulation of the type in which a closing body is prestressed against a valve seat by a helical spring. 
     2. Description of the Prior Art 
     In devices of the type with which this invention is concerned, an axially movable closing body is prestressed against an associated valve seat by means of a helical spring disposed coaxially to the closing body. 
     In devices of this generic type, an axially movable closing body is prestressed against the associated valve seat by means of a helical spring disposed coaxially to the closing body. Because of the instability of helical springs in the transverse direction, a compensation means is necessary to compensate for a resultant skewed spring position, since otherwise an uncontrolled lateral tilting behavior of the adjacently disposed closing body would occur, which would lead to an undefined response performance of the device. 
     From British Patent Disclosure GB 14 63 217, one such device is already known. In it, a compensation means is disposed axially between the closing body and the associated valve seat, in order to compensate for a skewed position of the helical spring and a resultant tendency to transverse tilting of the closing body. However, what is unsatisfactory in this prior art is that a positive-engagement contact between the compensation means and the closing body is necessary, which requires precision-fitted and therefore expensive production. Since furthermore the compensation means is in permanent engagement with the valve seat associated with the closing body, the flow resistance at the valve seat is undesirably increased in the open position of the closing body. 
     SUMMARY OF THE INVENTION 
     The device of the invention has the advantage over the prior art that because of the bracing, provided in the radial direction, of the compensation means on the inner wall of the housing, the radial force components generated by the helical spring under initial tension, are absorbed and compensated for, so that only the components generated in the axial direction by the helical spring are carried onward by the compensation means. Because of the disposition of the compensation means between the helical spring and the closing body, the flow resistance at the valve seat furthermore remains essentially unaffected. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing features and advantages of the invention will become apparent from the detailed description contained below, taken with the drawings, in which; 
     FIG. 1 shows a view in longitudinal section of a device according to the invention, which includes a housing with a closing body received in it; a helical spring with a compensation element is disposed between the closing body and one part of the housing; 
     FIG. 2 shows the device of FIG. 1 in a plan view; 
     FIG. 3 is a plan view showing the compensation element employed in the device; 
     FIG. 4 shows a cross section through the compensation element of FIG. 3; 
     FIG. 5 is a longitudinal section of a second embodiment of the device of the invention; dashed lines for the closing body and the compensation element represent a closed valve function, while the solid lines represent an opened valve function, in which the closing body is axially deflected out of its valve seat; 
     FIG. 6 is a longitudinal section of the compensation for an incident skewed spring position of the helical spring by bending of the compensation element; and 
     FIG. 7 is a longitudinal section of the compensation for an even greater skewed spring position by corresponding bending of the compensation element. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The device indicated in its entirety by reference numeral  10  in FIG. 1 has a housing  11 , in which a closing body  12  is received that is supported on a lower, narrowed-diameter region  11 ′ of the housing  11  embodied as a valve seat and is axially movable along the longitudinal axis  11 ″ of the housing  11 . In the axial direction, a helical spring  14  is disposed between the closing body  12  and a housing part  13 , embodied as a closure cap in the upper region of the housing  11 ; the upper end of the helical spring is seated within a central bulge in the closure cap  13 , and its opposite lower end is supported on a compensation element  15 , which with its central region  15 ′ acts upon the closing body  12 . To that end, the central region  15 ′ of the compensation element  15  is pre-curved in dome-shaped fashion in the direction of the adjacent closing body  12 ; that is, the central region  15 ′ has the approximate shape of a segment of a spherical shell, whose concave side faces toward the helical spring  14 ; spring arms  15 ″ of the compensation element  12  that protrude radially from the central region  15 ′ are braced resiliently with their ends on the inner wall of the housing  11 , so that as a result, the compensation element  15  is under transverse initial tension. A radially encompassing annular transitional portion  15 ′″ between the dome-shaped region  15 ′ of the compensation element  15  and the spring arms  15 ″ that protrude radially from the latter serves as what in the installed position is a plane bearing face for the associated end of the helical spring  14 ; the diameter of the annular transitional portion  15 ′″ is adapted to the diameter of the helical spring  14 . The compensation element  15  is in frictional-engagement contact, for instance, with the closing body  12 , since the apex as an extreme point of the dome-shaped region  15 ′ acts upon the bearing face  12 ′, facing toward it, of the closing body  12 , specifically approximately centrally in the longitudinal axis  11 ″ of the housing  11 . The closing body  12  is embodied cylindrically in its lower region  16 , and this region  16  is guided in a receiving bore  17  of the housing  11  that has a diameter corresponding to it. While the housing  11  is widened in diameter in stages upward in the axial direction from its bottom region  17 , the cylindrical region  16  of the closing body  12  is adjoined at the top by a sealing portion  19  in the form of a spherical segment associated with the valve seat  11 ′, and this portion ends at a radially outward-protruding collar  20 . Extending between the bottom region  17  of the housing  11  and the portion of the housing  11  that is embodied as the valve seat  11 ′ is a transitional portion, which has a larger diameter than the associated cylindrical region  16  of the closing body  12  and that has inlet openings  21  disposed transversely to the longitudinal axis  11 ″ of the housing  11 ; a hollow chamber approximately in the form of an annular gap extends between the wall of the transitional portion and the adjacent cylindrical region  16  of the closing body  12 . Outlet openings  22  are provided in the housing part  13  that closes off the housing  11  at the top. Since the closing body  12  with its spherical-layered sealing portion  19  is seated on the associated valve seat  11 ′, the device  10  is in the closed valve function position in FIG.  1 . 
     FIG. 2 on the one hand shows the location of the closure cap  13  and on the other the geometric disposition of the spring arms  15 ″, belonging to the compensation element  15 , inside the housing  11  of the device  10 . To that end, the closure cap  13  is inserted into the upper region of the housing  11 , and a radially encompassing, upward-protruding rim rests on the associated inner wall of the housing  11 . The closure cap  13  has, coaxially to the longitudinal axis  11 ″ of the housing  11 , a central outlet opening  22  and three recesses, spaced apart from one another in the circumferential direction, as outlet openings  22 , with spokelike struts located between them. For this purpose, the compensation element  15  likewise braced on the inner wall of the housing  11  has the spring arms  15 ″, which are spaced apart uniformly in the circumferential direction. 
     As FIG. 3 shows, the spring arms  15 ″ protruding radially from the dome-shaped region  15 ′ of the compensation element  15  for bracing purposes on the inner wall of the housing  11  are spaced apart uniformly in the circumferential direction; in the exemplary embodiment, this creates six spring arms, and thus the compensation element  15  has a sextuple symmetry. Also in the exemplary embodiment, the compensation element  15  is shaped from a leaflike steel sheet. From FIG. 4 it can be seen that the dome-shaped region  15 ′ has a substantially spherical curvature, thus resulting in a spherical shell segment. The dome-shaped region  15 ′ is bounded by the annular transitional portion  15 ′″, and between the circumference thereof and the respectively pivotably connected spring arm  15 ″, there is in each case a short, stepped shoulder  15 ″″, extending upward, obliquely to the axial direction, and disposed radially; the shoulder serves as a lateral stop for the movable end of the helical spring  14 . The spring arms  15 ″ thus pivotably connected to the central region  15 ′ via the transitional portion  15 ′″ and the respective shoulder  15 ″″ protrude radially outward approximately perpendicular to the respectively associated shoulder  15 ″″ and are arranged approximately in the shape of a star; in a variant embodiment, their ends are angled upward somewhat. In the non-installed state of the compensation element  15 , the spring arms  15 ″ are embodied as straight. 
     FIG. 5 shows the mode of operation of the device  10  of the invention in terms of a second embodiment, which differs from the first embodiment of FIGS. 1-4 in that the inner wall of the housing  11 , at the level of the spring arms  15 ″ of the compensation element  15  that engage it there, has a radially inward-protruding encompassing stop collar  24 , on which the spring arms  15 ″ come to rest. If the pressure introduced via the inlet openings  21  exceeds the counterpressure exerted on the closing body  12  by the helical spring  14 , then the closing body  12  is deflected axially upward with simultaneous compression of the helical spring  14 , and a flow conduit extends upward from the inlet openings  21 , through the annular-gaplike hollow chamber and past the spherical sealing portion  19  with the adjoining collar  20  to reach the outlet openings  22  provided in the closure cap  13 . This open valve function of the device  10  is shown by the solid lines for the axially displaceable closing body  12  and the compensation element  15  in FIG. 5, while by comparison the broken lines show the closed valve function. As FIG. 5 also shows, in the open valve function the axial deflection of the closing body  12 , via the frictionally engaged connection with the dome-shaped region  15 ′ of the compensation means  15 , leads to a slight isotropic bending of the spring arms  15 ″ braced on the inner wall of the housing. 
     FIG. 6 illustrates the mode of operation of the compensation means  15  in the event of a skewed position of the helical spring  14 . As the respective dashed and solid lines for the closing body  12  and the compensation element  15  in FIG. 6 show, this skewed position exists both in the closed and open position of the device  10 . As a result, the movable end, toward the closing body  12 , of the helical spring  14  exerts not only an axial force but also a force component in the radical direction. Since the movable end of the helical spring  14  acts upon the annular region  15 ′″ of the compensation element  15 , this skewed position causes torque bias of the dome-shaped region  15 ′, and the transverse and radial force component is absorbed by the laterally protruding spring arms  15 ″ braced on the inner wall of the housing  11 ; as a result, the spring arms  15 ″ oriented in the direction of the transverse torque bias become bent to a greater extent than the other spring arms  15 ″. The skewed state of the movable end of the helical spring  14  is thus compensated for by way of the dome-shaped region  15 ′ of the compensation element  15 . The radius of curvature of the dome-shaped region  15 ′ is selected such that the pivot point is located in the plane of the spring arms  15 ″, and a relative motion of the engagement point, located at the apex of the dome-shaped region  15 ′, between the compensation element  15  and the adjacent closing body  12  is thus maximally precluded, so that the contact point, defined by the apex of the dome-shaped region  15 ′, between the compensation element  15  and the adjacent bearing face  12 ′ of the closing body  12  is centered in the longitudinal axis  11 ″. The compressive force of the helical spring  14  is thus carried on axially, that is, without radial offset, to the closing body  12 . The compensation element  15  thus acts as a transverse force securing means, so that the closing body  12  is acted upon only in the axial direction and only centrally in the longitudinal axis  11 ″, independently of radial transverse forces. 
     FIG. 7 illustrates the mode of operation of the compensation element  15  in the event of an even more-pronounced skewed position of the helical spring  14  in the open position of the device  10 . While in the closed position, as the dashed lines show, the helical spring  14  acts upon the compensation element  15  concentrically to the longitudinal axis  11 ″, that is, without a skewed state, and the spring arms braced radially on the inner wall of the housing  11  are oriented isotropically, in the open position as shown by the solid lines, an eccentric displacement of the movable end of the helical spring  14  occurs relative to the longitudinal axis  11 ″. This in turn leads to a corresponding torque bias of the dome-shaped region  15 ′, and the spring arms  15 ″ oriented in the direction of the torque bias bend in accordance with the amount of torque bias, while the spring arms  15 ″ that are oriented away from the direction of the torque bias are virtually unaffected, thus resulting in an anisotropic response behavior of the spring arms  15 ″. Because of the embodiment of the compensation element  15 , a greater skewed spring position can thus be compensated for, so that with the device  10  of the invention, even helical springs with a major skewed position can be used. 
     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.