Method of controlling the magnetic gap length and the initial stroke length of a pressure surge fuel pump

A method of machining and assembling members of a fuel pump to produce a magnetic gap length for controlling the reciprocal movement of an armature assembly relative to a housing member and to produce an initial armature assembly stroke length before engagement of a valve member, said method comprising the steps of:

• fabricating a tubular member, fabricating an armature member with first and second end surfaces, machining the first end surface of the armature at a first given length from the second end surface of the armature, fixing the armature member on the tubular member to provide the armature assembly, machining on the tubular member at a second given length from the second end surface of the armature member a valve seat adapted to engage the valve member, fabricating the housing member to include a first axial bore, and a second axial bore extending from the first axial bore and defined by an inner surface having therein a magnetic gap defined, in part, by a surface extending radially outwardly from the inner surface, and a counterbore located in spaced axial outward relation from the radially outwardly extending surface and defined, in part, by an annular shoulder, machining the radially outwardly extending surface at a third given length from the annular shoulder, fabricating a bushing, fixing the bushing in the first axial bore of the housing member, and machining on the bushing at a fourth given length from the annular shoulder of the counterbore in the housing member a stop surface adapted to engage the valve member, assembling the armature assembly in the axial bore with the second armature assembly end surface and the housing member annular shoulder in coplanar relation, whereby the magnetic gap length is defined by the difference between the first and third lengths, and whereby the difference between the second and fourth lengths defines the initial stroke length before engagement of the armature assembly valve seat with the valve member.

A method of machining and assembling members of a fuel pump to produce a magnetic gap length for controlling the reciprocal movement of an armature assembly relative to a housing member and to produce an initial armature assembly stroke length before engagement of a valve member, said method comprising the steps of:

• fabricating a tubular member, fabricating an armature member with first and second end surfaces, machining the first end surface of the armature at a first given length from the second end surface of the armature, fixing the armature member on the tubular member to provide the armature assembly, machining on the tubular member at a second given length from the second end surface of the armature member a valve seat adapted to engage the valve member, fabricating the housing member to include a first axial bore, and a second axial bore extending from the first axial bore and defined by an inner surface having therein a magnetic gap defined, in part, by a surface extending radially outwardly from the inner surface, and a counterbore located in spaced axial outward relation from the radially outwardly extending surface and defined, in part, by an annular shoulder, machining the radially outwardly extending surface at a third given length from the annular shoulder, fabricating a bushing having thereon a valve stop adapted to engage the valve member, and fixing the bushing in the axial bore of the housing member so that the valve stop is located at a fourth given length from the housing member annular shoulder, assembling the armature assembly in the axial bore with the second armature assembly end surface and the housing member annular shoulder in coplanar relation, whereby the magnetic gap length is defined by the difference between the first and third lengths, and whereby the initial stroke length of the armature assembly is defined by the difference between the second and fourth lengths.