Fuel injection pump for internal combustion engines

A fuel injection pump for internal combustion engines, having a cylinder bushing (1) inserted into a housing bore (2), in which a pump piston (5) is axially guided, said pump piston defines a pump work chamber (9) in the cylinder bushing (1) by means of a face end (7) and is moved axially back and forth by a cam drive (11) against a force of a restoring spring (13), a roller tappet (15) includes a roller (17) connected to the pump piston (5) via a roller pin (25) disposed crosswise to an axis of a cylinder-shaped housing of the roller tappet (15) in which said cylinder-shaped housing is embodied as a slide apron (23), the roller (17) rolls on the race of a cam (21) of a camshaft (19) driven by the internal combustion engine;

• the roller pin (25) is axially secured by means of a contact of its axial ends with an interior wall (29) of a part (16) of the housing bore (2) which guides the roller tappet (15), the roller pin (25) is guided in a bearing shell (27), open in a direction toward the cam drive (11), in the cylinder-shaped housing (23) of the roller tappet (15) and the axial ends of the roller pin (25) are embodied as flat surfaces extending vertically to the axis of the roller pin (25) which form transition areas (31) towards a circumferential surface, the transition areas (31) form a part of a generated enveloping curve that is adapted to a cylindrical contour of the interior wall area (29) that forms the roller tappet guide (16) and a radius of the generated enveloping curve has a center which is the same as a radius of the tappet guide (16), and in the area of transition (31), the rotation-symmetrical roller pin (25) has a common diameter with the exterior wall surface of the slide apron (23) of the roller tappet (15) and slides together with the slide apron in the roller tappet guide (16) of the housing bore (2).