Attachment structure of fuel injection device nozzle plate
An engaging projection of a valve body engages with an interlocking groove of a nozzle plate and the nozzle plate is rotated relative to the valve body. The engaging projection moves in a lateral groove of the interlocking groove while elastically deforming an arm part (elastically deformable portion), and the engaging projection is accommodated in a recess (lock position in the interlocking groove) of the arm part. A bottom surface of the recess of the arm part is pushed against the engaging projection of the valve body by the elastic force of the arm part, and the engaging projection of the valve body is seated and fixed on the bottom surface of the recess of the arm part. Accordingly, the nozzle plate is fixed to the valve body while being retained via the engaging projection and the interlocking groove (interlocking means).
1. A fuel injection device comprising:
a nozzle plate having a nozzle hole for atomizing and injecting fuel flowing from a fuel injection port, the nozzle plate having an interlocking groove including an axial groove portion and a lateral groove portion communicating with the axial groove portion and extending in a circumferential direction of the nozzle plate, the lateral groove portion having an open base end communicating with the axial groove portion and a closed terminal end opposite the base end; and
a metal valve body having a front end side to which the nozzle plate is attachable, the front end side being provided with the fuel injection port, the valve body having an outer periphery and an engaging projection protruding from the outer periphery,
wherein the nozzle plate includes a cylindrical fitting part into which the front end side of the valve body is fitted, and a bottom wall part formed so as to close a first end of the cylindrical fitting part, the bottom wall part abutting against a front end surface of the valve body and having the nozzle hole, a second end of the cylindrical fitting part being an open end, the axial groove portion of the interlocking groove extending in an axial direction of the cylindrical fitting part from the open end,
wherein the cylindrical fitting part and the bottom wall part are made of synthetic resin and formed integrally,
wherein the cylindrical fitting part of the nozzle plate has an integral arm part configured as an elastically-movable cantilever between the open end of the cylindrical fitting part and the lateral groove portion of the interlocking groove, the arm part having a lateral groove wall facing the lateral groove portion, the lateral groove wall having a recess formed therein for receiving the engaging projection, the recess being located between the base end and the terminal end of the lateral groove portion so as to be spaced apart a distance from both the base end and the terminal end of the lateral groove portion, the distance being equal to at least a lateral width of the engaging projection,
wherein the cylindrical fitting part is fitted onto the front end side of the valve body until the bottom wall part abuts against the front end surface of the valve body such that the engaging projection of the valve body engages with the interlocking groove of the nozzle plate and is seated in the recess of the lateral groove wall of the arm part such that an elastic force of the arm part urges and presses the bottom wall part of the nozzle plate against the front end surface of the valve body, and
wherein the axial groove part of the interlocking groove has a width at least as large as the lateral width of the engaging projection to allow the engaging projection to pass through the axial groove part as the cylindrical fitting part is fitted onto the front end side of the valve body.
2. The fuel injection device according to claim 1 , wherein the interlocking groove is one of a pair of interlocking grooves formed at intervals of 180 degrees in the circumferential direction of the nozzle plate, and the engaging projection is one of a pair of engaging projections formed at intervals of 180 degrees in a circumferential direction of the valve body, each of the pair of engaging projections engaging a respective one of the pair of interlocking grooves.
3. The fuel injection device according to claim 1 , wherein the recess has a semi-circular cross section and is formed in a surface of the lateral groove wall to allow the engaging projection to seat therein.
4. The fuel injection device according to claim 1 , wherein a portion of the lateral groove wall between the terminal end of the lateral groove portion and the recess is inclined so as to smoothly guide the engaging projection from the terminal end of the lateral groove portion to the recess.
5. The fuel injection device according to claim 4 , wherein an inclined portion of the lateral groove wall is connected to the axial groove by a curved surface.
6. The fuel injection device according to claim 1 , wherein the lateral groove wall has a rotation preventing projection projecting in an axial direction of the cylindrical fitting part, the rotation preventing projection being located between the recess and the base end of the lateral groove portion.