CONSTRUCTION OF CONNECTING HEAD OF HIGH PRESSURE TUBES FOR FUEL INJECTION Russian patent published in 2010 - IPC F02M55/02 

FIELD: engines and pumps.

SUBSTANCE: construction of connecting head of high pressure tubes for fuel injection includes the following on connecting end of thick-wall steel tube of smaller diametre with relatively small diametre: spherical mounting surface, section of annular flange located at some distance from mounting surface towards tube axis centre, and conical surface located in fact near spherical surface continued from mounting surface to the section of annular flange or to the place located in close proximity to section of annular flange, and converging to the end. Retaining nut is installed so that it directly or indirectly interacts with rear surface of annular flange section. In case of thick-wall steel tube of small diametre the ratio t (thickness)/D (outer diametre) <0.3, distance L1 in axial direction from the end of connecting head to rear surface of annular flange is 0.38 D to 0.6 D, spherical radius R of mounting surface is 0.45 D to 0.65 D, and outer diametre D1 of annular flange section is 1.2 D to 1.4 D. Internal peripheral surface of head has circuit of section in axial direction of tube, which is close to diametre of internal peripheral surface of steel tube in fact on flat cylindrical surface and/or conical surface. There proposed is the second version of construction of connecting head of high pressure tubes for fuel injection, which includes the following on connecting end of thick-wall steel tube of smaller diametre, with relatively small diametre: spherical mounting surface. In case of thick-wall steel tube of small diametre the ratio t (thickness)/D (outer diametre) ≥0.3, distance L1 in axial direction from the end of connecting head to rear surface of annular flange is 0.38 D to 0.7 D, spherical radius R of mounting surface is 0.45 D to 0.65 D, and outer diametre D1 of annular flange section is 1.2 D to 1.4 D, and internal peripheral surface of head has circuit of section in axial direction of the tube, which is close to diametre of internal peripheral surface of steel tube in fact on flat cylindrical surface and/or conical surface.

EFFECT: invention allows preventing formation of cracks in the section of cavity, which is formed during formation of head, formation of cracks due to cavitation erosion and creation of tensile stress related to formation of cavity, and provides resistance to fatigue damage.

18 cl, 17 dwg