Abstract:
An improved thermostatic valve has an axially open annular slide and a base plate which together form a gasket seat, and has a restoring spring, which biases the annular slide in the direction toward the base plate. The restoring spring is mounted upon an abutment that is connected to the base plate instead of to the valve housing. The configuration of the claimed invention permits a thermostatic valve that may be assembled and tested prior to installation on an internal combustion engine.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of German patent application 10104179.9, filed Jan. 23, 2001, herein incorporated by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The invention relates to thermostatic valves, and particularly to a thermostatic valve that includes an axially open annular slide that can be displaced by means of a thermostatic operating element; a base plate that, together with an edge of the annular slide, forms a gasket seat and has a clamping edge and openings between the clamping edge and the gasket seat; a restoring spring, which biases the annular slide in the direction of the base plate; and an abutment for the restoring spring.  
         BACKGROUND OF THE INVENTION  
         [0003]    In typical thermostatic valves, a movable valve plate is driven by a thermostatic operating element between a closed position and an open position according to the temperature of the fluid being conveyed through the valve. Such valves provide for fairly precise control of coolant flow according to a desired operating temperature of the device, such as an internal combustion engine, which is being cooled. when a large-volume flow of coolant is required, however, known thermostatic valves present a number of disadvantages, chief among them the loss of coolant pressure because the coolant impinges upon the valve plate.  
           [0004]    In those cases in which large volume flows of coolant are required for cooling an engine, a thermostatic valve of the type mentioned at the outset is employed in place of a thermostatic valve that operates by means of a valve plate. In such annular slide thermostatic valves, an axial coolant flow passes through the annular slide during operation, and specifically when coolant is being conveyed to a radiator. Because the coolant does not impinge upon a valve plate, the pressure loss is fairly small.  
           [0005]    Such known thermostatic valves are typically supplied in parts and then assembled during installation in the coolant circuit of an internal combustion engine. Assembly in situ is required because the restoring spring for the annular slide and thermostatic operating element is supported on a cross arm, which is in turn supported on the housing on which the thermostatic valve is mounted. Because the parts are potentially fairly small and require precise alignment during assembly, it is desirable to have a thermostatic valve that is capable of being pre-assembled.  
         OBJECT AND SUMMARY OF THE INVENTION  
         [0006]    It is therefore an object of the present invention to provide for an improved thermostatic valve which provides for larger-volume coolant flows and is capable of being installed in a pre-assembled state.  
           [0007]    Specifically, the present invention provides for a thermostatic valve whose restoring spring is mounted on the base plate of the valve.  
           [0008]    Because the restoring spring is mounted on the base plate of the valve rather than on a cross arm which must be supported on the valve housing, the present invention makes it possible to pre-assemble the elements of the thermostatic valve into a component which can, in turn, be mounted between two parts of a housing or the like. In addition to reducing the costs of installation, pre-assembly of the valve makes it possible to check the seal between the annular slide and the base plate before installation.  
           [0009]    In one embodiment of the invention, a shackle, the ends of whose legs are fastened on shoulders of the base plate, is used as the abutment for the restoring spring. It is helpful to design the shoulders of the base plate as open hooks, which engage with the ends of the legs of the shackle. This feature simplifies the pre-assembly process, because the shackle and restoring spring may be easily mounted by pushing and rotating the shackle.  
           [0010]    In another embodiment of the invention, the shackle may be equipped with a collar, which serves to guide the housing of the thermostatic operating element. Such a collar provides a means by which the thermostatic operating element may be aligned with the shackle.  
           [0011]    In still another embodiment of the invention, the end of the annular slide facing away from the gasket seat is provided with strips which are essentially oriented radially inward and hold a mounting, which fixes the annular slide in place on the housing of the thermostatic operating element. In this embodiment it is advantageous to design the mounting as a circumferential ring, which is supported in the axial direction on an annular shoulder of the housing of the thermostatic operating element, because the connection between the annular slide and the housing of the thermostatic operating element is thereby made easily and securely.  
           [0012]    Further characteristics and advantages of the invention will be seen in the following description of the thermostatic valve, in accordance with the invention represented in the drawing. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0013]    The single drawing FIGURE is an axial cross-sectional view of a thermostatic valve in accordance with the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0014]    The thermostatic valve represented in the drawing has a base plate  10 , which is used as a support element for the remaining parts of the thermostatic valve. A cutout  11  is provided in the center of the base plate, into which a work piston  12  of a thermostatic operating element  13  has been inserted. The housing  14  of the thermostatic operating element is connected to an annular slide  15 . The annular slide  15  has an essentially cylindrical shape. The edge  16  of annular slide  15  that faces base plate  10  is slightly widened toward the exterior and sealingly engages with a contact face of base plate  10 , forming a gasket seat  17 . As can be seen from the drawing, the two faces constituting the gasket seat  17  are obliquely inclined at approximately 45° and widen in the direction of flow.  
         [0015]    Base plate  10  is bowl-shaped and arches toward thermostatic operating element  13 . Gasket seat  17  is located in the edge area of the underside of this bowl. Connecting strips  18  adjoin the bowl-shaped area and extend radially toward the exterior. Preferably three strips  18  are arranged at spacings of 120° around the circumference of the base plate  10  and thereby define apertures through which coolant may flow. These strips  18  lead to a clamping edge  19 , which is in the shape of a circumferentially closed ring. A relatively large free-flow cross-section exists between gasket seat  17  and clamping edge  19  and is only interrupted by connecting strips  18 .  
         [0016]    The edge of annular slide  15  that faces away from gasket seat  17  is provided with inwardly directed connecting strips  20 , whose inner ends make a transition into a ring-shaped holder  21 . Ring-shaped holder  21  of annular slide  15  rests against an annular collar  22  of housing  14  of thermostatic operating element  13  on the side located opposite work piston  12 . Guide insert  23  is received in the housing  14  in the area of this annular collar  22  and, on one hand, constitutes a guide for operating piston  12  and, on the other hand, is used for the sealed clamping of a bag diaphragm, which seals the interior of the housing  14  from the outside. An expanding material, which may be a wax mixture, is located in housing  14  and is designed so that, at a pre-selected temperature, it expands and drives out the work piston.  
         [0017]    With the extension of work piston  12 , housing  14  of thermostatic operating element  13  is moved away from base plate  10 , taking along annular slide  15  so that edge  16  of annular slide  15  comes free of gasket seat  17 .  
         [0018]    A restoring spring  24  is assigned to housing  14  of thermostatic operating element  13  and is biased against the extension of work piston  12  (i.e. to urge annular slide  15  toward base plate  10 ). When the coolant temperature (and thus the temperature of the thermostatic operating element  13 ) falls, the wax mixture contained in housing  14  contracts. Restoring spring  24  is therefore able to push housing  14  back and force work piston  12  back into housing  14 . The restoring spring  24  is supported at one end on holder  21  of annular slide  15 , so that holder  21  is securely maintained on housing  14  of thermostatic operating element  13 , while annular slide  15  is biased in the direction of the base plate  10  at the same time. The other end of restoring spring  24 , which is pre-stressed to a pre-selected force, is supported by means of a shackle-shaped abutment  25 . Shackle  25  is provided with a collar  26 , which serves to center shackle  25  with housing  14  of thermostatic operating element  13  as well as to provide a seat for the restoring spring  24 . Ends  27  of the legs of shackle  25 , which legs are oriented toward base plate  10 , are angled toward the exterior and received and suspended in hooks  28  which project from base plate  10 . Hooks  28  are open, so that ends  27  of the legs of shackle  25  can be suspended from the hooks  28  by rotating them about the longitudinal axis of the thermostatic operating element  13 .  
         [0019]    The thermostatic valve, which includes base plate  10 , thermostatic operating element  13 , annular slide  15  and shackle  25 , is pre-assembled from these elements to form a component. As the last step shackle  25  is inserted between strips  20  of annular slide  15 , in the course of which restoring spring  24  is compressed. By rotating shackle  25 , the angled ends  27  of the legs of shackle  25  are suspended in hooks  28 , which extend as shoulders from base plate  10 , to complete pre-assembly of the thermostatic valve. As can be seen from the drawing, protrusions  29  are provided at the ends of the slits of the hooks  28 , so that the angled-off ends  27  are snapped together with the hooks  28 .  
         [0020]    This pre-assembled component is then mounted between two elements  30 ,  31  of a housing, which receive the clamping edge  19  of the base plate between them, and a gasket ring is also inserted. Housing element  30  is provided with an inflow connector, which is connected with an engine outlet, so that coolant flowing from the internal combustion engine flows to the thermostatic valve in the direction of arrow  32 . Housing element  30  is further provided with a bypass connector  33 , through which the coolant flows back to the internal combustion engine in the direction of arrow  34 , as long as the thermostatic valve remains closed. Housing element  30  is provided with a sliding gasket ring  35 , which rests against the exterior circumference of the annular slide  15  in the area facing away from gasket seat  17  and thus blocks the connection with the openings in the base plate  10 .  
         [0021]    When the in-flowing coolant has been sufficiently heated, so that the reaction temperature of thermostatic operating element  13  has been reached, work piston  12  of thermostatic operating element  13  is driven out of housing  14 , so that the annular slide  16  is lifted off gasket seat  17 . Because of this the coolant can flow axially through the interior of annular slide  15  and flow off to a coolant radiator in the direction of arrow  36  through the openings in the base plate  10 . The position of the annular slide determines the ratio of the amount of coolant flowing through the bypass (arrow  34 ), directly to the engine, to the amount flowing to the coolant radiator (arrow  36 ) before returning to the internal combustion engine. During a purely cooling operation, work piston  12  is extended sufficiently far that annular slide  15  blocks bypass connector  33 , and the entire amount of coolant flows to the coolant radiator.  
         [0022]    In the embodiment represented, base plate  10  is a shaped metal element, and particularly a die-cast element. Annular slide  15  and shackle  25  are shaped sheet metal elements. In another embodiment, base plate  10  is likewise a shaped sheet metal element. In still other embodiments, base plate  10 , annular slide  15 , or shackle  25 , or any combination of them, are made of plastic.  
         [0023]    It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a full and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.