A hydraulic coupling is specified, particularly for fuel injectors, which has a housing pot having a pot bottom and a lateral pot surface, a piston guided axially displaceably in the housing pot, a fluid-filled coupling gap that is provided between the piston and the pot bottom, diaphragm situated on the outer side of the housing pot facing away from the piston, a compensation chamber that is bordered by the diaphragm and flow-connected to the coupling gap, and a spring element acting upon the diaphragm with an axially directed spring force. In order to achieve a low overall stiffness of the hydraulic coupling at the required specified coupling force, the spring element is developed as a spring bracket fixed to the housing pot, which lies against the diaphragm with axial prestressing in the region of the pot bottom.

A cup is in a bottomed tubular shape to receive an injector along an injector axis. A bracket is extended from a sidewall of the cup. The bracket includes at least one arm and a body. The at least one arm connects the body with the cup. The body forms a screw opening configured to receive a screw along a screw axis. The body has a pivot end on an opposite side of the screw axis from the injector axis.

A fuel pump includes a housing provided with an axial bore defining a compression chamber. The pump is further provided with a cylindrical piston slidably arranged in the bore, the piston extending from a top extremity that is inside the bore, defining a high pressure extremity, to a lower extremity, defining a low pressure extremity. The piston is able to reciprocally slide between a lower position where fuel at low pressure enters the compression chamber via an inlet and, a top position where fuel present in the compression chamber is pressurized before being expelled via an outlet. The piston is also provided with a recess surrounded by a peripheral wall arranged on its high pressure extremity, the recess and peripheral wall enabling the piston to expand radially when fuel in the compression chamber is pressurized.