Abstract:
The present invention relates to an electromagnetic valve of a cartridge-type construction comprised of a magnetic core, a magnetic armature ( 12 ) with valve closure member ( 4 ), and a valve seat member which form an operative unit in a valve housing, the said valve housing including a closed sleeve portion ( 1 ) which has a collar ( 17 ) on the opposite open end area for attachment in the valve housing. Inserted telescopically into the open end area of the sleeve portion ( 1 ) is a sleeve-shaped annular part ( 2 ) which carries the valve seat member ( 3 ) and aligns the latter concentrically in relation to the valve closure member ( 4 ) to form an operative unit.

Description:
TECHNICAL FIELD 
     The present invention generally relates to valves and more particularly relates to an electromagnetic valve for use in hydraulic brake systems. 
     BACKGROUND OF THE INVENTION 
     DE 196 24 377 A1 discloses an electromagnetic valve of this type which includes a magnetic core, a magnetic armature with a valve closure member, and a valve seat member as preadjusted components that are preassembled in a valve housing to form an operative valve unit. The valve housing includes a dome-shaped sleeve portion which abuts with the open collar-shaped end area on a supporting plate that is mounted in a bore of the cartridge-type valve housing. The bore is encompassed by a thick-walled valve housing portion which is deformed to a calked shape on the exterior. 
     One shortcoming is related to the adjustment of the magnetic armature stroke by means of an adjusting pin that has to be adjusted in the magnetic core before the collar is calked in the cartridge. 
     In DE-A-195 29 724 an electromagnetic valve is described which has a valve member in a valve housing which is actuatable in response to the valve operating position of a valve closure member that abuts on the valve member in the initial position, to what end a spring-applied entraining means guided in the valve housing is in engagement with the valve member and with a tappet-shaped extension on the valve closure member. 
     An object of the present invention is to manufacture an electromagnetic valve of the type initially referred to by means which are as simple, inexpensive and reliable as possible, with the valve being distinguished by a miniaturized, especially slim design. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a first embodiment of an open two-way/two-position directional control valve which is not energized electromagnetically in its initial position. 
     FIG. 2 is a variation of the electromagnetic valve shown in FIG. 1 in the area of the valve seat member and on the annular part close to the valve housing. 
     FIG. 3 is a closed electromagnetic valve, which is not energized magnetically in the inactive position and also is configured as a two-way/two-position directional control valve. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The embodiment of FIG. 1 shows a considerably enlarged cross-sectional view of an electromagnetic valve having a magnetic core which forms the annular part  2  that is essential to the present invention. The annular part  2 , configured as a cartridge closure means, is inserted telescopically into the open end area of a sleeve portion  1  that guides the magnetic armature  12  so that the stroke of the magnetic armature can be adjusted by the extent the annular part  2  is slipped into the sleeve portion  1 . Remote from the sleeve portion  1  on the annular part  2  is valve seat member  3  which is press fitted until abutment on the annular part  2  in the present embodiment. According to the embodiment of FIG. 1, the valve seat member  3  includes a housing step into which, in turn, a diaphragm retainer  10  is press fitted, at the peripheral surface of which an annular gasket  11  is guided. The outside and inside shoulders  11 ′,  11 ″ of the annular gasket  11  are compressed over a large surface between the end surfaces of the valve seat member  3  and the diaphragm retainer  10 . The advantage is that no undesirable deformation occurs at the annular gasket  11  that is configured as a non-return valve when fluid flows along the gasket lip. The undesirable deformation of the gasket has so far been prevented by special measures which obstruct the flow cross-section. 
     As can be seen in FIG. 1, the diaphragm retainer  10  along with the valve seat member  3  and the non-return gasket  11  forms a subassembly which is press fitted into the bottom end of the annular part  2  until abutment thereon without special adjusting measures. 
     A plate-type filter is provided in the diaphragm retainer  10  to filter the pressure fluid flow in the present embodiment, while an annular filter  14  is positioned in the area of the transverse bore  8  in the annular part  2 . 
     The adjustment of the electromagnetic valve is thus limited, on the one hand, to the displacement of the magnetic armature  12  on the tappet-shaped portion of the valve closure member  4  until the desired residual air slot between the end surfaces of the magnetic armature  12  and the diametral annular part  2  is reached. On the other hand, it is limited to slipping in or press fitting the annular part  2  into the sleeve portion  1  until the desired valve stroke is reached. Subsequently, the sleeve portion  1  is coupled to the annular part  2  by means of a welding seam  15  to secure the adjusted position. The result is an especially slim operative valve cartridge which is inserted into a stepped bore of a block-shaped accommodating member  16 , for example, and is calked in the area of the collar  17  spread apart at the sleeve portion  1 . To this end, the material of the accommodating member  16 , in the area of the bore step, is press fitted to the inclined surface of the collar  17  by means of an exterior calking tool. A supporting plate  18  made of high-strength steel is arranged below the collar  17  in the stepped bore to accommodate the relatively great calking force. The use of the supporting plate  18  is appropriate in the event that the accommodating member  16  is made of a relatively soft material, for example, a light metal. When the accommodating member  16  is made of steel, this obviates the need for the supporting plate  18 . Beneath the supporting plate  18 , the transverse bore  8  connects the stepped bore  6  to the pressure fluid conduit  9  in the accommodating member  16  so that in the open position of the electromagnetic valve according to the drawing, an unimpaired hydraulic connection to a pressure fluid channel which is continued below the plate-type filter  13  is established. 
     It should be noted in addition that the dome-shaped sleeve portion  1  and the annular part  2  are made of a ferritic steel which ensures that both parts can properly be welded to each other. According to the drawings, the sleeve portion  1  carries a magnet valve coil  19  which contacts with its yoke ring  20  a magnet end plate  21  proximate the collar  17 . 
     With reference to the features of the electromagnetic valve according to FIG. 1, now the structural differences compared to FIG. 1 will be shown by way of FIG.  2 . As shown in FIG. 2, the annular part  2  completing the valve cartridge has a two-part design, with the thick-walled first annular part  2 ′ configured as a magnetic core being press fitted into the thin-walled second annular part  2 ″ which receives the valve seat member  3 . The thin-walled second annular part  2 ″ forms a subassembly of the electromagnetic valve, comprised of the valve seat member  3  disposed within the second annular part  2 ″ and a plate-type non-return valve  22  arranged beneath the valve seat member  3  in the second annular part  2 ″. Valve  22  is mounted inside a filter cartridge  23  that is also integrated in the second annular part  2 ″. Another distinguishing feature in relation to the electromagnetic valve according to FIG. 1 is due to the arrangement of the annular filter  14  which, instead of being integrated in the annular part  2 , is now arranged on the outside of the second annular part  2 ″. With respect to the other details of the electromagnetic valve which have so far not been mentioned in the description of FIG. 2, the preceding explanations of the electromagnetic valve according to FIG. 1 will be referred to. 
     It shall not be left unmentioned in the comparison of both embodiments that regarding the details, still other alternatives or combinations are possible which are, however, of secondary importance to the present invention. 
     Finally, an embodiment for implementation of the present invention for an electromagnetic valve that is closed in its magnetically deenergized initial position according to FIG. 3 will be explained hereinbelow. FIG. 3 also shows the design which is essential for the present invention according to the preceding embodiments of FIGS. 1 and 2, comprised of a telescopically combined valve cartridge made up of a sleeve portion  1  which carries the valve coil  19 , into which a thin-walled annular part  2  is press fitted and subsequently welded until the desired valve stroke is reached. Corresponding to the function of the electromagnetic valve, a magnetic core is disposed in the dome area of the sleeve portion  1  and has a stepped bore housing a spring that is active in the valve closing direction and supported on the front surface of the magnetic armature  12 . The magnetic armature  12  is radially guided both in the area of the sleeve portion  1  and in the area of the annular part  2 , with the result that the valve closure member  4  is aligned concentrically to the valve seat member  3  that is press fitted into the bottom area of the annular part  2  exactly as in the illustration according to FIG.  1 . At the tapered cross-sectional area of the annular part  2 , an annular filter  14  is in abutment on a bead of the valve seat member  3 , thereby eliminating the need for the bottom bore step in the accommodating member  16 , as is apparent from FIG.  2 . As in FIG. 1, a comparatively straight bore portion is achieved in the accommodating member  16  so that the step of the valve accommodating bore in the accommodating member  16  is limited to the area where calking is effected. Therefore, FIG. 1 which has already been explained is referred to concerning details about the calking area and the other assemblies.