| 摘要 |
PROBLEM TO BE SOLVED: To improve a flow coefficient by a method wherein the opening section area of a nozzle hole is varied by using a rotary valve, the occurrence of disturbance of a flow of fuel between the nozzle holes and further unevenness in spray characteristics are reduced as much as possible. SOLUTION: By paying an attention to a fact that the peripheral wall surface of the coupling protrusion part for rotation (a mounting shaft part 35) of a rotary valve 33 is formed in uniform contact with nozzle holes as much as possible, a rotary valve 33 seating a seat surface connected to the nozzle hole and a drive shaft 32 to drive the rotary valve 33 are provided. By driving the rotary valve 33, the opening section area of the nozzle hole is changeable. In a so formed variable nozzle hole type fuel injection nozzle, a mounting shaft part 35 between the rotary valve 33 and the drive shaft 32 has a circular surface making contact with a fuel flow passage leading toward the nozzle hole and being formed in a circular shape.
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