A fuel pump includes a mechanical regulating valve arranged in a pump body which modulates the pressure in a high pressure space so that the pressure matches the engine demand. Modulation by the regulating valve requires adjustment of the inlet fuel quantity, adjustment of the volume of the high pressure space, and control of a return fluid communication enabling fuel to exit the high pressure reservoir.

Displacement control device (1) for variably adjusting the displacement of an axial piston hydraulic pump comprising a rotary shaft (10) mounted in a housing (20) and rotatable around a shaft axis (13) of the rotary shaft (10). The rotary shaft (10) having a first end (11) and a second end (12), wherein to the second end (12), which protrudes outside of the housing (20), a torque can be applied for rotating the rotary shaft (10) to open and close servo pressure lines (40, 45) arranged within the housing (20). The servo pressure lines (40, 45) can conduct hydraulic fluid to and from a servo adjusting unit capable to adjust the displacement volume of the axial piston hydraulic pump. The rotary shaft (10) further comprising a mid-portion (14) located between the first end (11) and second end (12). Concentric to the shaft axis (13) in the mid-portion (14) of the rotary shaft (10) a detent sleeve (5) is positioned comprising an abutment area (7) onto which, in the neutral position of the displacement control device (1), a sliding element (8) abuts, which is mounted pre-stressed in the housing exerting a resilient force onto the detent sleeve (5) perpendicular to the shaft axis (13), wherein the detent sleeve (5), in operating conditions of the displacement control device (1) is rotatable fixed with the rotary shaft (10) and turns with the rotary shaft (10). However, for neutral position adjustments in non-operating conditions, the detent sleeve (5) and the rotary shaft (10) are detachable from each other such that the rotary shaft (10) can be turned relative and independently within the detent sleeve (5), which is held in its neutral position by the sliding element (8).

Displacement control device (1) for variably adjusting the displacement of an axial piston hydraulic pump comprising a rotary shaft (10) mounted in a housing (20) and rotatable around a shaft axis (13) of the rotary shaft (10). The rotary shaft (10) having a first end (11) and a second end (12), wherein to the second end (12), which protrudes outside of the housing (20), a torque can be applied for rotating the rotary shaft (10) to open and close servo pressure lines (40, 45) arranged within the housing (20). The servo pressure lines (40, 45) can conduct hydraulic fluid to and from a servo adjusting unit capable to adjust the displacement volume of the axial piston hydraulic pump. The rotary shaft (10) further comprising a mid-portion (14) located between the first end (11) and second end (12). Concentric to the shaft axis (13) in the mid-portion (14) of the rotary shaft (10) a detent sleeve (5) is positioned comprising an abutment area (7) onto which, in the neutral position of the displacement control device (1), a sliding element (8) abuts, which is mounted pre-stressed in the housing exerting a resilient force onto the detent sleeve (5) perpendicular to the shaft axis (13), wherein the detent sleeve (5), in operating conditions of the displacement control device (1) is rotatable fixed with the rotary shaft (10) and turns with the rotary shaft (10). However, for neutral position adjustments in non-operating conditions, the detent sleeve (5) and the rotary shaft (10) are detachable from each other such that the rotary shaft (10) can be turned relative and independently within the detent sleeve (5), which is held in its neutral position by the sliding element (8).

A fuel pump includes a mechanical regulating valve arranged in a pump body which modulates the pressure in a high pressure space so that the pressure matches the engine demand. Modulation by the regulating valve requires adjustment of the inlet fuel quantity, adjustment of the volume of the high pressure space, and control of a return fluid communication enabling fuel to exit the high pressure reservoir.