Control valve assembly and method of manufacturing thereof

A fuel injector comprising:

• a control valve assembly comprising:
• a first valve arrangement wherein a first valve spool is guided in a first hydraulic bore provided in a body of the control valve assembly, said first valve spool being adapted to move between a closed position wherein a first shoulder face of a first head member of said first valve spool is in sealing contact against a first seating face, and a fully open position wherein a first distant end face of said first head member is in flush continuity with a first under face of the body of the control valve assembly, the shoulder face of the first valve spool being lifted away from said first seating face;
• and
• a first tubular sleeve having a seating portion having an end face which defines said first seating face, the first tubular sleeve being fixed in the first hydraulic bore and the first valve spool extending through said first tubular sleeve,
• wherein the body of the control valve assembly comprises a valve guide member provided with the first hydraulic bore and a valve plate having an upper face and an opposed under face, the upper face being arranged in surface abutment against an under face of the valve guide member, said valve plate being further provided with a through opening aligned with the first hydraulic bore, the first tubular sleeve being fixed in the valve guide member so that the first seating face lies parallel and proximate to the under face of the valve guide member, either recessed inside the first hydraulic bore or protruding in the through opening.

A method of manufacturing a control valve assembly having a first valve arrangement wherein a first valve spool is guided in a first hydraulic bore provided in a body of the control valve assembly, said first valve spool being adapted to move between a closed position wherein a first shoulder face of a first head member of said first valve spool is in sealing contact against a first seating face, and a fully open position wherein a first distant end face of said first head member is in flush continuity with a first under face of the body of the control valve assembly, the shoulder face of the first valve spool being lifted away from said first seating face;

• and a first tubular sleeve having a seating portion having an end face which defines said first seating face, the first tubular sleeve being fixed in the first hydraulic bore and the first valve spool extending through said first tubular sleeve, wherein the body of the control valve assembly comprises a valve guide member provided with the first hydraulic bore and a valve plate having an upper face and an opposed under face, the upper face being arranged in surface abutment against an under face of the valve guide member, said valve plate being further provided with a through opening aligned with the first hydraulic bore, the first tubular sleeve being fixed in the valve guide member so that the first seating face lies parallel and proximate to the under face of the valve guide member, either recessed inside the first hydraulic bore or protruding in the through opening, the method comprising the steps of:
• providing the valve body defining the first hydraulic bore;
• providing the first valve spool having the head member joining a first core via the first shoulder face;
• providing the first tubular sleeve adapted to be inserted in said first hydraulic bore;
• engaging, and inserting with press fit, said first tubular sleeve in said first hydraulic bore so that the first seating face is in close vicinity to a second under face of the valve body;
• arranging the first valve spool so that the first core extends in the first tubular sleeve and the first head member is outside the first tubular sleeve, the first shoulder face being able to cooperate with the first seating face;
• and
• adjusting the position of the first tubular sleeve to a desired first maximum lift of the first valve spool.