STRUCTURE FOR CONNECTING HEAD PORTION OF HIGH-PRESSURE FUEL INJECTION TUBE

WIPO Patent Application WO/2007/105659

A1

[PROBLEMS] To provide a high-pressure fuel injection tube having high resistance to breakage from fatigue, which is achieved by preventing generation of cracks in a pocket portion during forming of a head portion, generation of cracks due to erosion by cavitation, and occurrence of tensile stress caused by formation of the pocket portion. [MEANS FOR SOLVING PROBLEMS] The high-pressure fuel injection tube has, at a connecting end of a thick-wall small-diameter steel tube, a spherical seat surface, an annular flange portion, and a conical surface contiguous to the seat surface and incorporating a washer and a fastening nut. When a tube material satisfying the relationship of t (wall thickness)/D(outside diameter) < 0.3 is used, the axial distance from the end of the connecting head portion to the back face of the annular flange portion is in a range from 0.38D to 0. 6D, the spherical radius of the seat surface is in a range from 0.45D to 0.65D, and the outside diameter of the annular flange portion is in a range from 1.2D to 1.4D. When the inner peripheral surface of the connecting head portion has a substantially flat circular tubular surface or conical surface and a tube material satisfying the relationship of t (wall thickness)/D (outside diameter) ≥ 0.3 is used, the axial distance from the end of the connecting head portion to the back face of the annular flange portion is in a range of 0.38D to 0.7D.

JP2005526930	High-pressure accumulator for combustion injection system with built-in pressure regulating valve
JP6441824	A device for injecting fuel into the combustion chamber of an internal combustion engine
WO/1991/011608	FUEL-INJECTION SYSTEM FOR INTERNAL-COMBUSTION ENGINES

KATO NOBUO (JP)
HAYASHI KOICHI (JP)
USUI SHOICHIRO (JP)

PCT/JP2007/054731

September 20, 2007

March 09, 2007

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USUI KOKUSAI SANGYO KK (JP)
KATO NOBUO (JP)
HAYASHI KOICHI (JP)
USUI SHOICHIRO (JP)

F02M55/02

JP2005009460A	2005-01-13
JPH0464793A	1992-02-28
JP2002322965A	2002-11-08
JP2003336560A	2003-11-28
JP2005180218A	2005-07-07
JPS5535220A	1980-03-12

See also references of EP 1995445A4

OSHIDA, Yoshitaka et al. (3-12 Ginza 3-chom, Chuo-ku Tokyo 61, JP)

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