Yamaha Hatsudoki Kabushiki Kaisha

Nippon Steel Corporation

Usui Co., Ltd.

Tatsuya Masuda

Yousuke Ishida

Taizo Makino

Masahiro Yamazaki

Yuji Arai

Osamu Endo

Katsunori Nagao

Tsugumi Yamazaki

Naoki Serizawa

Tomohiko Omura

Mamoru Suzuki

Tsutomu Okuyama

Hiroaki Kondo

Masashi Omoto

Michio Saitou

Noriki Tsukiji

A steel pipe for a fuel injection pipe has a chemical composition consisting of, by mass %: C: 0.17 to 0.27%, Si: 0.05 to 0.40%, Mn: 0.30 to 2.00%, P: 0.020% or less, S: 0.0100% or less, O: 0.0040% or less, Ca: 0.0010% or less, Al: 0.005 to 0.060%, N: 0.0020 to 0.0080%, Ti: 0.005 to 0.015%, Nb: 0.015 to 0.045%, Cr: 0 to 1.00%, Mo: 0 to 1.00%, Cu: 0 to 0.50%, Ni: 0 to 0.50%, V: 0 to 0.15%, and the balance: Fe and impurities. The metal micro-structure consists substantially of tempered martensite, or tempered martensite and tempered bainite. A prior-austenite grain size number is 9.0 or more. The hardness is within the range of 350 to 460 HV1. When a maximum value of a square root of an area of inclusions observed in a cross section perpendicular to a longitudinal direction of the steel pipe is taken as a(n=1 to 20), a maximum value aof ais 30.0 μm or less, and an average value aof ais 40% or more of a.

Steel pipe for fuel injection pipe, and fuel injection pipe using same

A steel pipe for a fuel injection pipe has a chemical composition consisting of, by mass %: C: 0.17 to 0.27%, Si: 0.05 to 0.40%, Mn: 0.30 to 2.00%, P: 0.020% or less, S: 0.0100% or less, O: 0.0040% or less, Ca: 0.0010% or less, Al: 0.005 to 0.060%, N: 0.0020 to 0.0080%, Ti: 0.005 to 0.015%, Nb: 0.015 to 0.045%, Cr: 0 to 1.00%, Mo: 0 to 1.00%, Cu: 0 to 0.50%, Ni: 0 to 0.50%, V: 0 to 0.15%, and the balance: Fe and impurities. The metal micro-structure consists substantially of tempered martensite, or tempered martensite and tempered bainite. The hardness is within the range of 350 to 460 HV1. A lattice spacing of a (211) diffraction plane measured by CoKα characteristic X-ray diffraction is 1.1716 Å or less, and a half-value width of the (211) diffraction plane is 1.200° or less. The number density of cementite having a diameter of 50 nm or more is 20/μmor less.

A steel pipe has a composition consisting, by mass percent, of, C: 0.12 to 0.27%, Si: 0.05 to 0.40%, Mn: 0.3 to 2.0%, Al: 0.005 to 0.060%, N: 0.0020 to 0.0080%, Ti: 0.005 to 0.015%, Nb: 0.015 to 0.045%, Cr 0 to 1.0%, Mo: 0 to 1.0%, Cu: 0 to 0.5%, Ni: 0 to 0.5%, V: 0 to 0.15%, and B: 0 to 0.005%, the balance being Fe and impurities. As impurities, contents are Ca: 0.001% or less, P: 0.02% or less, S: 0.01% or less, and O: 0.0040% or less. The micro-structure is tempered martensitic or tempered martensite and tempered bainite, in which a prior-austenite grain size number is 10.0 or more. Tensile strength is TS 800 MPa or higher. Critical internal pressure is [0.3'TS′a] or more, a=[(D/d)−1]/[0.776′(D/d)], D: pipe outer diameter (mm), d: pipe inner diameter (mm).

Steel pipe for fuel injection pipe and fuel injection pipe using the same

A steel pipe for fuel injection pipe has a tensile strength of 500 to 900 MPa and a yield ratio of 0.50 to 0.85, and has a critical internal pressure (IP) satisfying [IP&#x2265;0.41&#xd7;TS&#xd7;&#x3b1;] (&#x3b1;=[(D/d)&#x2212;1]/[0.776&#xd7;(D/d)], where TS: tensile strength (MPa) of the steel pipe, D: steel pipe outer diameter (mm), and d: steel pipe inner diameter (mm)), wherein a circumferential-direction residual stress on an inner surface of the pipe is &#x2212;20 MPa or lower after the steel pipe is split in half in a pipe axis direction.

Steel pipe for fuel injection pipe and method for producing the same

A secondary sheave shaft of a transmission is disposed vertically higher than a drive shaft when viewed along the axial direction of the shafts. An idle shaft of a speed-reduction mechanism is disposed between a primary sheave and an imaginary plane that extends through an axis of rotation of the secondary sheave shaft and an axis of rotation of the drive shaft. The drive shaft is disposed inside a profile of a transmission case when viewed along the axial direction of the secondary sheave shaft and the drive shaft.

Saddle-type vehicle and engine

An engine has a built-in continuously variable transmission (CVT) interconnecting a crankshaft connected through a connecting rod to a piston and a transmission shaft to which the rotation of the crankshaft is transmitted for changing speed between both of the shafts. A driven pulley and a clutch are disposed on the transmission shaft. A balancer shaft to which the rotation of the crankshaft is transmitted and the clutch are disposed in an overlapping positional relationship with each other in the direction of the crankshaft.

Engine with built-in continuously variable transmission

An engine has a continuously variable transmission in which a drive pulley is attached to an end of a crankshaft. The drive pulley is coupled by a flexible transmitter to a driven pulley. The driven pulley is attached to an end of a transmission shaft. A centrifugal clutch mechanism is axially aligned with the transmission shaft. The centrifugal clutch is positioned inboard of the driven pulley. A case supports the crankshaft and the transmission shaft. The case comprises a first case portion and a second case portion that are joined along a plane that is positioned between the driven pulley and a longitudinal plane that intersects an axis of a cylinder of the engine.

Engine incorporating a V-belt type continuously variable transmission

A saddle-type vehicle has an engine unit with a continuously variable transmission. The transmission has a primary sheave and a secondary sheave that are connected by a flexible transmitter such as a belt. The primary sheave, the secondary sheave and the belt are positioned in a transmission case. A starting kick shaft is positioned on the same side of the engine unit as the transmission case but the starting kick shaft is positioned outside of a profile of the transmission case when the engine unit is viewed from a lateral side.

An engine is constructed such that respective centers of gravity of a crank shaft, a balancer shaft and a cylinder are positioned close to one another and the mass of the engine is thus centralized. The engine includes a shaft center of a cylinder that is offset to one side with respect to a shaft center of a crank shaft, and a balancer shaft is disposed on a side of the engine where the cylinder shaft center is offset with respect to a first parallel line which intersects with the crank shaft center and extends substantially parallel to the cylinder shaft center.

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Shizuoka, Japan

Tatsuya Masuda