FUEL INJECTION PUMP FUR INJECTION INTERNAL-COMBUSTION ENGINES

The invention refers to a Brennsto££einspritzpumpe for Einspritzbrenrtkra£tmaschlnen with at least into a drilling pump-goes uses assigned Pumpenelement, which exhibits a pump piston can and a thrust piece, which under inserting the pressure control valve seat of exhibiting pressure control valve body against the pump piston can is pressed, whereby pump piston can, pressure control valve bodies and thrust piece essentially resemble outside diameters to exhibit and into a common drilling of the Einspritzpumpengehäuses are inserted. Inserted seals do not withstand high injection pressures and it in these cases the front surfaces by pump piston can, pressure control valve housing and thrust piece directly and seals inserted without in contact are with one another brought between the sealing surfaces, whereby these front surfaces are finely polished, polished or lapped, so that the together pressed front surfaces themselves result in the poetry. With such a training it is well-known to divide the sealing surfaces by in one of the surfaces with one another in contact arranged groove into an inside and an outside piston area in order to increase the specific Flächendruck. The outside piston area is necessary hiebei for the exact position adjustment of the pressure control valve body in the drilling of the printing pump housing and it is by this outside piston area the danger of tilting or an inclined position of the pressure control valve body with the installation to be avoided. Also with such a training leakage oil losses however still show up with high pressures, which today already peak values of 1200 bar reach, whereby the depressing leakage oil forms so-called firing channels, which become larger in the course of the enterprise. An excessive enlargement of the contact pressures is not however possible for firmness reasons. The invention refers now to such an fuel injection pump, with which the pump piston can, pressure control valve body and thrust piece under avoidance of a poetry with the pressure control valve body in contact stand directly and the contact surfaces between pressure control valve bodies and pump piston can and between pressure control valve bodies and thrust piece are limited to one inside and an outside piston area each, and consists essentially of that the Mantefläche at least one pressed, of thrust piece, the against each other, printing vent [lkörper and Pumpenkolbenbiichse of formed parts, in particular the lateral surface of the pressure control valve body at least one enular groove exhibits, yields themselves radially inward at least up to a radius extended, which corresponds to the internal radius of the outside piston area. In this kind within the range of the outside piston areas a suspension is reached, which reduces the contact pressure within the range of these outside piston areas. Hiedurch is increased pressing power the affecting the unit area of the internal piston area and thus the Dichtwlrkung is improved, without pressing the sealing surfaces of causative clamping organs together, as screws are more highly stressed od.dgl.. The GDR patent specification Nr.15944 training of an injection pump with a pressure control valve body is, more softly an enular groove exhibits to infer however it concerns completely different a pump type. The pressure control valve body rests not against the pump piston can and also not against these is pressed, but is only into the housing under inserting a guidance can assigned. Thus pressing conditions can be determined by this well-known enular groove in no way. Appropriately extends the enular groove up to a radius, which corresponds at the most to the external radius of the internal piston area. It will thus transfer directly the pressing power to the internal piston area, while the outside piston area is relieved to a large extent. At the lateral surface of the construction unit concerned ring bulges are isolated by the enular groove or enular grooves, which carry the outside piston areas serving for the poetry. The strength of these ring bulges in axial direction measured determines the suspension and thus the Anpreßkra£t. The stronger this Ringwü'Iste is, the more largely is the contact pressure. If the enular groove is intended in the lateral surface of the Druckventflkörpers, then the middle width of this enular groove determines the strength that it limiting ring bulges. In accordance with the invention appropriately the middle width of the enular groove measured in axäaler direction corresponds to a quarter to a third, preferably approximately half of axial extending of the pressure control valve body. In the case of such a calculation a sufficient suspension of the pressure control valve body within the range of the outside piston areas is reached. In the designs the invention is described on the basis a remark example. Fig.1 shows a cross section by the injection pump in the range of a Pumpenlementes. Fig.2 shows a cross section in larger yardstick by the upper parts of a Pumpenelementes. Fig.1 shows a one-digit injection pump with external drive, which under switching Flun in the cross section by the axle of a Pumpenelementes --100-- to the crankshaft housing of the Brennkra£tmaschine flanged on and by a cam --101-- one in the crankshaft housing stored wave is propelled, whereby that the roller shaft --102-- prominent beginning --103-- by a breaking through of the crankshaft housing through-rises up. The invention can find however in the same way also with a usual one-digit or Einsprltzpumpe of several characters with own cam shaft application. In a drilling --1-- the Einsprltzpumpengehäuses --2-- is a pump piston can --3--, a thrust piece --4-- and a pressure control valve body --5-- accommodated. In the Druckventi] body --5-- is the Druckventilsltz --6-- planned, approximately yield the pressure control valve cone --7-- by the pressure control valve feather/spring --8-- one presses. --9-- is a spacer, which for the centring of the pressure control valve feather/spring --8-- serves. --10-- the connection is flir the fuel line. By a clamping plate --11-- becomes thrust piece --4--, Pressure control valve bodies --5-- and pump piston can --3-- together-pressed. Between the pressure control valve body --5-- and the pump piston can --3-- on the one hand and between the Druckventflkörper --5-- and the thrust piece --4-- on the other hand no seals are intended, but the bright polished and/or polished or lapped surfaces of these parts fit together. The surfaces of the pressure control valve body point one groove each --12-- up and the surface of the thrust piece standing with the pressure control valve body in contact is --13-- circularly exceptionally. In this way internal piston areas become --14-- and expresses piston areas --15-- formed, on the soft contact of the pressure control valve body --5-- with the pump piston can --3-- and the contact of the pressure control valve body --5-- with the thrust piece --4-- is limited. The contact surfaces are refined by the restriction on this Rängfläehen and the Flächendruck at these contact surfaces is thus increased. The two enular grooves ---12--- are by a drilling --16-- connected and this drilling stands over a cross hole --17-- with the annular gap --18-- between pressure control valve bodies --5-- and housing bore --1-- in connection. In this kind can over the two internal piston areas --14-- withdrawing leakage oil back to the suction chamber --19-- arrive to the injection pump. Such a construction represented in Fig.1 is well-known. In not clamped condition a slight play at the circular sealing surfaces exists --14 and 15-- both at the lower and at the upper surface of the pressure control valve body, i.e. thus both between Druckventflkörper --5-- and thrust piece --4--, and between pressure control valve bodies --5-- and pump piston can --3--. With training according to invention is now this entire play between the outside piston areas with one another in contact --15-- slightly more largely than the entire play between the internal piston areas with one another in contact --14--. Thus the outside piston areas become --15-- relieved and the entire on the internal piston areas --14-- working pressing force is increased. Fig.2 shows another execution form of the invention in the larger yardstick. This execution form differs from the execution form to Fig.1 only thereby that at the lateral surface of the pressure control valve body --5-- an enular groove --20-- is intended. This enular groove extends radially inward over the internal radius --R-- the Ringfläehen --15-- outside almost up to the outside radius --r-- the internal Rängfläche - 14--. The middle width measured in axial direction ---A-- this enular groove --20-- corresponds approximately half to axial extending --b-- the pressure control valve body --5--. In this way become within the range of the outside Rängfläche --15-- two flanges --21-- formed, which can fit with springs slightly against each other, so that the specific FIächendrnck within the range of the outside piston area --15-- one reduces. On the internal piston areas --14-- expenditure-practiced specific Flächendruck rises from there, there in this range the volIe material cross section of the pressure control valve body --5-- is maintained. The sealing effect of the internal Ringfiächen is improved from there. With the remark example of the designs is the enular groove --20--- in the pressure control valve body --5-- planned. In addition, it can in place of this enular groove --20-- or additionally to this an appropriate enular groove in to the piston areas --15-- adjacent ranges of the coat of the thrust piece --4-- and the pump piston can --3-- intended its. In all cases thus the specific Flächendruck within the range of the outside piston areas becomes during continuous total pressing --15-- reduced and daflir the specific Flächendruck within the range of the internal piston areas --14-- increased, so that the sealing effect is improved, without increasing the material stressing.