Manufacturing method for fuel pump
A stator has ribs, which are configured to make contact with an inner wall of a housing when accommodated in the housing. In a deformation process, force is applied from a radially outside to first portions of the housing to elastically deform the housing. In an insertion process subsequent to the deformation process, the stator is inserted into the housing, such that the ribs are enabled to make contact with second portions of the housing, which are elastically deformed radially outward. In an affixation process subsequent to the insertion process, application of the force is released to cause the ribs to make contact with an inner wall of the housing.
1. A manufacturing method for a fuel pump, the fuel pump comprising:
a housing in a tubular shape;
a pump cover equipped to one end of the housing, the pump cover having an inlet port for drawing fuel;
a cover end equipped to an other end of the housing, the cover end having an outlet port for discharging fuel;
a stator in a tubular shape, the stator equipped with a plurality of windings, the stator having a plurality of ribs, which are configured to make contact with an inner wall of the housing when accommodated in the housing;
a rotor rotatable on a radially inside of the stator;
a shaft coaxial with the rotor and rotatable integrally with the rotor; and
an impeller equipped to an end of the shaft on a side of the pump cover, the impeller rotatable with the shaft to pressurize fuel flowing from the inlet port and to discharge fuel through the outlet port,
the manufacturing method comprising:
applying force from a radially outside to a plurality of first portions of a sidewall of the housing on a radially outside to elastically deform the housing in a deformation process, the housing being formed of a metallic material in an annular form in cross section perpendicular to a center axis;
inserting the stator into the housing, such that the ribs, which are formed of resin, are enabled to make contact with second portions of the sidewall of the housing, the second portions being elastically deformed radially outward, in an insertion process subsequent to the deformation process; and
releasing application of the force to cause the ribs to make contact with the inner wall of the housing, in an affixation process subsequent to the insertion process, wherein the sidewall of the housing, with which the ribs make contact, is in the annular form in cross section perpendicular to the center axis, wherein
in the affixation process, each of the ribs makes contact with the inner wall to form a cover-end-side gap and a pump-cover-side gap with the inner wall at portions, which are adjacent to the rib in a direction of the center axis,
the cover-end-side gap is located on a side of the cover end,
the pump-cover-side gap is located on a side of the pump cover,
in the affixation process, the stator makes contact with the inner wall at a contact portion, and
the contact portion is located on an opposite side of the cover-end-side gap from the rib in the direction of the center axis.
2. The manufacturing method according to claim 1 , wherein the ribs are equipped to a radially outside of the stator and located at a regular interval.
3. The manufacturing method according to claim 1 , wherein in the affixation process, the ribs make contact with the inner wall at intermediate positions each being located between the first portions on which the force are applied from the radially outside.
4. The manufacturing method according to claim 1 , wherein the force from the radially outside is caused with compressed air.
5. The manufacturing method according to claim 1 , wherein in the affixation process, application of the force is released
to recover the inner wall radially inward into the annular form to cause the inner wall to make contact with the ribs
to regulate a position of the stator relative to the housing in a direction of the center axis of the housing and
to align a center axis of the stator relative to the center axis of the housing.
6. The manufacturing method according to claim 1 , wherein each of the ribs is formed in a part of the stator in a direction of the center axis.
7. The manufacturing method according to claim 1 , wherein in the affixation process, application of the force is released to recover the sidewall of the housing into the original annular form in cross section.
8. The manufacturing method according to claim 1 , wherein in the affixation process, the stator makes contact with the inner wall via the end cover at the contact portion.
9. The manufacturing method according to claim 1 , wherein
the stator has a cross section perpendicular to the center axis,
the cross section is in a regular polygonal shape,
the stator has a plurality of flat surfaces on a radially outside,
the ribs protrude radially outward from at least two of the flat surfaces, respectively, and
the ribs are arranged alternately at a regular interval in a circumferential direction about the center axis.
10. The manufacturing method according to claim 1 , wherein
the stator has a cross section perpendicular to the center axis,
the cross section is in a hexagonal shape having six flat surfaces,
the ribs protrude radially outward from three of the six flat surfaces, respectively, and
the ribs are arranged alternately at a regular interval in a circumferential direction about the center axis.