WO2010071014A1 - Bielle, moteur à combustion interne, appareil de transport et procédé de fabrication de bielle - Google Patents

Bielle, moteur à combustion interne, appareil de transport et procédé de fabrication de bielle Download PDF

Info

Publication number
WO2010071014A1
WO2010071014A1 PCT/JP2009/069993 JP2009069993W WO2010071014A1 WO 2010071014 A1 WO2010071014 A1 WO 2010071014A1 JP 2009069993 W JP2009069993 W JP 2009069993W WO 2010071014 A1 WO2010071014 A1 WO 2010071014A1
Authority
WO
WIPO (PCT)
Prior art keywords
connecting rod
main body
less
rod main
rod
Prior art date
Application number
PCT/JP2009/069993
Other languages
English (en)
Inventor
Tsuyoshi Kubota
Tatsuhiko Sato
Hirotaka Kurita
Original Assignee
Yamaha Hatsudoki Kabushiki Kaisha
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Yamaha Hatsudoki Kabushiki Kaisha filed Critical Yamaha Hatsudoki Kabushiki Kaisha
Priority to JP2011518617A priority Critical patent/JP5433692B2/ja
Publication of WO2010071014A1 publication Critical patent/WO2010071014A1/fr

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C7/00—Connecting-rods or like links pivoted at both ends; Construction of connecting-rod heads
    • F16C7/02—Constructions of connecting-rods with constant length
    • F16C7/023—Constructions of connecting-rods with constant length for piston engines, pumps or the like

Definitions

  • the present invention relates to a connecting rod and a production method thereof.
  • the present invention also relates to an internal combustion engine and a transportation apparatus including a connecting rod.
  • a connecting rod in an internal combustion engine, a member which is called a connecting rod (or con rod) is used for linking a crankshaft to a piston.
  • a connecting rod includes: a bar- like rod main body (axis portion) ; a small end which is provided at one end of the rod main body; and a big end which is provided at another end of the rod main body. The small end is connected to a piston, whereas the big end is connected to a crankshaft.
  • the connecting rod reciprocates inside the internal combustion engine. Therefore, by reducing the weight of the connecting rod, the internal combustion engine is allowed to have smoother rotations and reduced vibrations. Thus, the connecting rod is expected to be light weight. [0004] Moreover, an explosion force occurring in the combustion chamber is transmitted to the connecting rod via the piston, and therefore the connecting rod is required to have sufficient mechanical strength. In particular, the connecting rod of an internal combustion engine which is operated at high revolutions (e.g., an internal combustion engine of a motorcycle) is required to have an even higher mechanical strength, and is expected to have a further reduced weight for improved acceleration performance.
  • an internal combustion engine which is operated at high revolutions (e.g., an internal combustion engine of a motorcycle) is required to have an even higher mechanical strength, and is expected to have a further reduced weight for improved acceleration performance.
  • a carburization treatment which allows carbon to permeate the surface of a connecting rod.
  • a carburization treatment increases the carbon concentration in the surface vicinity of the connecting rod, and therefore an increased surface hardness is obtained after hardening of the connecting rod.
  • the mechanical strength of the connecting rod is improved.
  • the connecting rod can be reduced in weight. Note that, even when performing a carburization treatment, it is often the case that the rod main body is subjected to a treatment for preventing carburization, so as not to have a high surface hardness. The reason is that the rod main body should preferably be high in toughness.
  • Patent Literature 1 proposes a high-concentration carburization treatment as a technique of further enhancing the surface hardness of a connecting rod.
  • carburization is performed a plural number of rounds in an ambient atmosphere having a carbon potential (CP) of 0.8% or more.
  • CP carbon potential
  • carbide in minute particulate form deposits in the surface vicinity of the connecting rod, and also the crystal grain size of martensite structure in the surface vicinity is reduced.
  • the surface hardness is remarkably- increased.
  • FIG. 8 shows exemplary production steps of a connecting rod in the case where a high-concentration carburization treatment is performed.
  • step SIl a raw material of steel is molded into the shape of a connecting rod through forging.
  • step SIl masking is applied to the surface of the connecting rod with an anti-carburization agent or the like.
  • step S12 masking is applied to the surface of the connecting rod with an anti-carburization agent or the like.
  • step S13 a machining is performed to form a piston pin hole in the small end, a crankpin hole in the big end, and so on.
  • step S14 The carburization is performed in an ambient atmosphere having a carbon potential of 0.8% or more. At this time, the carbon concentration in the surface vicinity is increased in any portion that is not covered by the masking pattern, e.g., the inner peripheral surface of the crankpin hole (that is, any portion from which the masking pattern has been removed through cutting at the time of machining) . On the other hand, in any portion that is covered by the masking pattern, e.g., the rod main body (that is, any portion that has been subjected to a carburization prevention treatment) , the carbon concentration is scarcely changed. Next, the remaining masking pattern on the surface of the connecting rod is removed (step S15) .
  • step S16 a second round of carburization, a hardening, and a tempering are seguentially performed.
  • the second round of carburization is also performed in an ambient atmosphere having a carbon potential of 0.8% or more.
  • the carbon concentration in the surface vicinity is increased over the entire connecting rod.
  • a polishing step for the inner peripheral surface of the small end and the inner peripheral surface of the big end is performed (step S17) .
  • FPB Fine- particle Bombarding
  • a fine-particle shot peening fine particles which are much finer than those used for traditional shot peening are used as the shot material (e.g., having diameters of 500 ⁇ m or less) .
  • the fine-particle shot peening is a technique of allowing such fine particles to rapidly collide against the surface of a metal part to modify the surface by utilizing various phenomena occurring as a result .
  • Patent Literature 1 Japanese Laid-Open Patent Publication No. 2000-313949 [Non-Patent Literature]
  • Non-Patent Literature 1 Chuji Kagaya and one other, “Trends of Surface Origination Using High Velocity Impact Phenomena of Fine Particles", Denkiseiko (or “Electric Steelmaking") , January 2000, Vol. 71, No. 1, pp.51-58
  • Non-Patent Literature 2 Shin-ichi TAKAGI and four others, “Surface Nonocrystallization of Carburized Steel JIS-SCr420 by Fine Particle Peening", Tetsu to Hagane (or “Iron and Steel”), 2006, Vol. 92, No.
  • FIG. 9 (a) is a cross- sectional view schematically showing the surface vicinity of a connecting rod before being subjected to a fine-particle shot peening
  • FIG. 9 (b) is a cross-sectional view schematically showing the surface vicinity of the connecting rod after being subjected to a fine-particle shot peening.
  • the present invention has been made based on the above findings of the inventors, and an objective thereof is to provide a connecting rod whose rod main body has an excellent mechanical strength and which is suitable for weight reduction, as well as a production method thereof. [Solution to Problem]
  • the connecting rod according to the present invention is a connecting rod including: a rod main body; a small end provided at a first end of the rod main body; and a big end provided at a second end of the rod main body; wherein, the connecting rod is made of a steel; a residual compressive stress in at least a portion of a surface of the rod main body is 1000 MPa or more; and circumcircle diameters of carbide and circumcircle diameters of inclusions contained in a surface vicinity of the rod main body are each 10 ⁇ m or less .
  • the steel has an oxygen content of 10 wtppm or less and a sulfur content of 0.01wt% or less.
  • a carbon concentration of the rod main body at a depth of 0.1 mm from the surface thereof is no less than 0.9wt% and no more than 1.2wt%.
  • An internal combustion engine according to the present invention includes a connecting rod having the above construction.
  • a transportation apparatus comprises an internal combustion engine having the above construction.
  • a production method for a connecting rod according to the present invention is a production method for a connecting rod including a rod main body, a small end provided at a first end of the rod main body, and a big end provided at a second end of the rod main body, the method comprising the steps of: providing a workpiece made of a steel containing no less than 0.1wt% and no more than 0.45wt% of carbon, 10 wtppm or less of oxygen, and 0.01wt% or less of sulfur; performing a plural number of rounds of carburization treatment for the workpiece in an ambient atmosphere having a carbon potential of 0.9% or more, where a last round of carburization treatment among the plural number of rounds of carburization treatment is performed in an ambient atmosphere having a carbon potential of no less than 0.9% and no more than 1.2%; and performing a fine-particle shot peening for the workpiece after having been subjected to the carburization treatment
  • the step of performing a fine-particle shot peening is performed so that a residual compressive stress in at least a portion of a surface of the rod main body is 1000 MPa or more.
  • a residual compressive stress in at least a portion of the surface of the rod main body is 1000 MPa or more. That is, a residual compressive stress which is greater than what would be conferred by a traditional shot peening is conferred to the connecting rod according to the present invention. Specifically, a residual compressive stress of 1000 MPa or more can be conferred through a fine- particle shot peening. Conventionally, when a fine-particle shot peening is performed for a connecting rod which has been subjected to a high-concentration carburization treatment, carbide and inclusions protruding from the surface of the parent phase would become causes of breakage.
  • circumcircle diameters of carbide and inclusions contained in the surface vicinity of the rod main body are as small as 10 ⁇ m or less, so that stress concentration at the surface is prevented, and breakage originating from the surface is unlikely to occur.
  • the connecting rod according to the present invention since a residual compressive stress as large as 1000 MPa or more is conferred to the surface and also breakage originating from the surface is unlikely to occur, the connecting rod according to the present invention has an excellent fatigue strength.
  • the connecting rod according to the present invention since the connecting rod according to the present invention is unlikely to experience breakage originating from the surface even when subjected to a fine-particle shot peening, it can be suitably produced by using a high- concentration carburization treatment and a fine-particle shot peening in conjunction. Therefore, the connecting rod according to the present invention has a connecting rod main body with an excellent mechanical strength, and is suitable for weight reduction.
  • inclusions whose circumcircle diameters have the possibility of growing to 10 ⁇ m or more are oxide and sulfide.
  • the oxygen content in the steel By setting the oxygen content in the steel to 10 wtppm or less, the circumcircle diameters of the oxide are ensured to be 10 ⁇ m or less.
  • the sulfur content in the steel By setting the sulfur content in the steel to 0.01wt% or less, the circumcircle diameters of the sulfide are ensured to be 10 ⁇ m or less.
  • the circumcircle diameters of the inclusions are 10 ⁇ m or less.
  • the circumcircle diameters of the carbide are ensured to be 10 ⁇ m or less.
  • the carbon potential of the ambient atmosphere when performing the last round of carburization treatment is substantially equal to the carbon concentration at a depth of 0.1 mm from the surface of the rod main body of the completed connecting rod.
  • the connecting rod according to the present invention is suitably used for various types of internal combustion engines. Since the connecting rod according to the present invention is suitable for weight reduction, an internal combustion engine having the connecting rod according to the present invention has an improved response.
  • the connecting rod according to the present invention Since the weight of the connecting rod is reduced, the weight of a reciprocating portion in the internal combustion engine is reduced, so that primary vibration (vibration which occurs due to reciprocation of the reciprocating portion including the piston and the connecting rod, with a cycle of one per rotation of the crankshaft) can be reduced. Furthermore, the connecting rod according to the present invention has an excellent fatigue strength, and therefore the reliability of the internal combustion engine is also improved. [0032] When an internal combustion engine having the connecting rod according to the present invention is used in a transportation apparatus, there is little primary vibration thus providing a much smoother ride for a passenger. Moreover, since there is no need to provide countermeasures against vibration for the vehicle body, a significant reduction in weight can be realized.
  • a workpiece which is made of a steel containing no less than 0.1wt% and no more than 0.45wt% of carbon is subjected to a plural number of rounds of carburization treatment in an ambient atmosphere having a carbon potential of 0.9% or more. That is, a high- concentration carburization treatment is performed. Furthermore, a fine-particle shot peening is performed for the workpiece which has been subjected to the high- concentration carburization treatment. Through this fine- particle shot peening, a large residual compressive stress can be conferred to the surface of the workpiece.
  • a workpiece which is made of a steel containing 10 wtppm or less of oxygen and 0.01wt% or less of sulfur is provided. Therefore, the circumcircle diameters of oxide and sulfide in the surface vicinity of the completed connecting rod can be ensured to be 10 ⁇ m or less. Moreover, since the carbon potential of the ambient atmosphere when performing a last round of carburization treatment among the plural number of rounds of carburization treatment is 1.2% or less, the circumcircle diameter of carbide in the surface vicinity of the completed connecting rod is ensured to be 10 ⁇ m or less.
  • the circumcircle diameters of carbide and inclusions are as small as 10 ⁇ m or less, even if a fine-particle shot peening is performed after the high-concentration carburization treatment, breakage originating from the surface is unlikely to occur. Therefore, with the production method for the connecting rod according to the present invention, a connecting rod having an excellent fatigue strength is produced. Moreover, since a fine-particle shot peening is performed in addition to a high-concentration carburization treatment in the production method for the connecting rod according to the present invention, there is provided a connecting rod whose connecting rod main body has an excellent mechanical strength and which is suitable for weight reduction.
  • the step of performing a fine-particle shot peening is preferably performed in such a manner that the residual compressive stress at the surface of the portion corresponding to the rod main body of the workpiece is as large as possible, or specifically, so that the residual compressive stress in at least a portion of the surface of the rod main body is 1000 MPa or more.
  • a connecting rod whose rod main body has a good mechanical strength and which is suitable for weight reduction, as well as a production method thereof.
  • FIG. 1 A diagram schematically showing a connecting rod 1 according to a preferred embodiment of the present invention, where: (a) is a plan view; (b) is a cross- sectional view taken along line IB-IB 1 in (a) ; and (c) is a cross-sectional view taken along line 1C-1C in (a).
  • FIG. 2 A cross-sectional view schematically showing a surface vicinity of the connecting rod 1 according to a preferred embodiment of the present invention.
  • FIG. 3 A flowchart showing a production method for the connecting rod 1 according to a preferred embodiment of the present invention.
  • FIG. 4 (a) is a diagram schematically showing metallographical structure which is formed in the surface vicinity of the connecting rod 1 through a first round of carburization treatment, and (b) is a diagram schematically showing metallographical structure which is formed in the surface vicinity of the connecting rod 1 through a second round of carburization treatment.
  • FIG. 5 A graph showing results of performing a bending fatigue test for actual parts, with respect to Examples 1 to 4, Comparative Examples 1 to 5, and conventional connecting rods .
  • FIG. 6 A cross-sectional view schematically showing an internal combustion engine 100 having the connecting rod 1 according to a preferred embodiment of the present invention.
  • FIG. 7 A side view schematically showing a motorcycle having the internal combustion engine 100 shown in FIG. 6.
  • FIG. 8 A flowchart showing a production method for a conventional connecting rod.
  • FIG. 9 (a) is a cross-sectional view schematically showing the surface vicinity of a connecting rod before being subjected to a fine-particle shot peening; and (b) is a cross-sectional view schematically showing the surface vicinity of the connecting rod after being subjected to a fine-particle shot peening.
  • FIGS. 1 (a) to (c) show a connecting rod 1 according to the present embodiment.
  • FIG. 1 (a) is a plan view schematically showing the connecting rod 1.
  • FIG. 1 (b) is a cross-sectional view taken along line IB-IB 1 in FIG. 1 (a) .
  • FIG. 1 (c) is a cross-sectional view taken along line 1C-1C in FIG. l(a) .
  • the connecting rod 1 includes: a rod main body 10; a small end 20 which is provided at one end (first end) of the rod main body 10; and a big end 30 which is provided at another end (second end) of the rod main body 10.
  • the connecting rod 1 is made of steel.
  • the rod main body (axis portion) 10 has a bar shape. A cross-sectional shape of the rod main body 10 is typically the letter "H", as shown in FIG. 1 (c) .
  • the small end 20 has a throughhole (piston pin hole) 22 through which a piston pin is to be inserted. The small end 20 is connected to a piston via the piston pin.
  • the big end 30 has a throughhole (crankpin hole) 32 through which a crankpin is to be inserted.
  • the big end 30 is connected to a crankshaft via the crankpin.
  • a rolling bearing such as a roller bearing is typically placed in the crankpin hole 32, and so an inner peripheral surface 32a of the crankpin hole 32 is in contact with the rolling bearing.
  • carbide 3 has deposited in the surface vicinity of the connecting rod 1.
  • the carbide 3 may be Fe 3 C or Cr 3 C, for example.
  • inclusions 4 such as oxide and/or sulfide also exist in the surface vicinity of the connecting rod 1.
  • the oxide may be Al 2 O 3 or SiO 2
  • the sulfide may be FeS or MnS, for example.
  • the connecting rod 1 has been subjected to a fine-particle shot peening, whereby a residual compressive stress is conferred thereto.
  • the parent phase 2 has been ground off through the fine-particle shot peening, the carbide 3 and inclusions 4 protrude from the surface 2a of the parent phase 2, at the surface of the connecting rod 1.
  • a residual compressive stress of 1000 MPa or more is conferred to at least a portion of the surface of the rod main body 10.
  • a traditional shot peening can only confer a residual compressive stress of about 700 MPa to about 800 MPa at the most.
  • a residual compressive stress which is greater than what would be conferred by a traditional shot peening is conferred to the connecting rod 1 of the present embodiment.
  • the residual compressive stress can be measured with an x-ray- residual stress measurement apparatus, for example.
  • circumcircle diameters Dl and D2 of the carbide 3 and inclusions 4 contained in the surface vicinity (specifically, a region down to a depth 0.05 mm from the surface) of the rod main body 10 are as small as 10 ⁇ m or less each, so that stress concentration at the surface of the rod main body 10 is prevented, whereby breakage originating from the surface is suppressed.
  • the circumcircle diameter Dl of the carbide 3 and the circumcircle diameter D2 of the inclusions 4 are, literally, diameters of imaginary circles circumscribed around the carbide 3 and inclusions 4, as can be seen from FIG. 2.
  • the sizes of the carbide 3 and inclusions 4 (e.g., the aforementioned circumcircle diameters) can be measured with a metallurgical microscope
  • the connecting rod 1 of the present embodiment since a residual compressive stress as large as 1000 MPa or more is conferred to the surface and also breakage originating from the surface is unlikely to occur, the connecting rod 1 of the present embodiment has an excellent fatigue strength. Moreover, since the connecting rod of the present embodiment has been subjected to a high- concentration carburization treatment and a fine-particle shot peening during its production steps, the connecting rod main body 10 has an excellent mechanical strength, and thus the connecting rod is suitable for weight reduction. When a conventional connecting rod is subjected to a fine-particle shot peening in addition to a high-concentration carburization treatment, breakage originating from the surface may occur.
  • the connecting rod 1 of the present embodiment is unlikely to experience breakage originating from the surface, so that it can be suitably produced by a production method which involves both a high-concentration carburization treatment and a fine-particle shot peening.
  • FIG. 3 is a flowchart showing production steps of the connecting rod 1.
  • a workpiece which has been molded via forging from a steel containing no less than 0.1wt% and no more than 0.45wt% of carbon is provided (step Sl) .
  • SCM420 which is chrome molybdenum steel
  • SCM420 contains 0.18wt% to 0.23wt% carbon, 0.90wt% to 1.20wt% chromium and 0.15wt% to 0.30wt% molybdenum.
  • SCr420, SCM435, SCM440, or the like for the steel which is the workpiece material.
  • the steel used in the present embodiment has an oxygen content of 10 wtppm or less, and a sulfur content of 0.01wt% or less.
  • a steel which is commonly-used as the material of the connecting rod has an oxygen content of 15 wtppm or more, and a sulfur content of about 0.020wt%.
  • a steel having a smaller oxygen content and a smaller sulfur content i.e., highly clean steel
  • the workpiece may be molded by sintering, casting, sinter forging, or the like, for example.
  • step S2 the workpiece is machined.
  • the outer dimensions of the workpiece after forging are adjusted. For example, removal of burrs, formation of the piston pin hole 22 and the crankpin hole 32, end-facing of the small end 20 and the big end 30, and the like are performed.
  • step S3 the workpiece is subjected to a first round of carburization and a hardening (or furnace cooling) (step S3) .
  • This carburization treatment is performed in an ambient atmosphere having a carbon potential of 0.9% or more. Note that no masking is applied to the workpiece before performing the carburization treatment.
  • the temperature of the first round of carburization treatment is set equal to or greater than the Al transformation point (i.e., a eutectic transformation temperature of the steel) .
  • the surface of the steel is excessively carburized.
  • FIG. 4 (a) schematically shows metallographical structure which is formed in the surface vicinity of the connecting rod 1 through the first round of carburization treatment. As shown in FIG. 4 (a) , mesh-like carbide 3 has deposited in between relatively large crystal grains 2' of martensite.
  • step S4 the workpiece is subjected to a second round of carburization, a hardening, and a tempering (step S4) .
  • This carburization treatment is performed in an ambient atmosphere having a carbon potential of no less than 0.9% and no more than 1.2%.
  • the temperature of the second round of carburization treatment is set equal to or greater than the Al transformation point but equal to or less than the Acm transformation point (i.e., a transformation temperature at which cementite deposits from austenite of the steel) .
  • the carbon within the excessively-carburized surface layer diffuses into the interior.
  • FIG. 4 (b) schematically shows metallographical structure which is formed in the surface vicinity of the connecting rod 1 through the second round of carburization treatment. As shown in FIG. 4 (b) , carbide 3 in minute particulate form has deposited in between relatively small crystal grains 2' of martensite.
  • a fine-particle shot peening is performed for the workpiece which has been subjected to the plural number of rounds of carburization treatment (step S5) .
  • This step is carried out to ensure that there is a residual compressive stress of 1000 MPa or more (and more preferably 1200 MPa or more) in at least a portion of the surface of the rod main body 10.
  • the rod main body 10 becomes thinner from the big end 30 toward the small end 20. Therefore, regarding the surface of the rod main body 10, it is preferable that there is a residual compressive stress of 1000 MPa or more in at least the vicinity of the small end 20. Of course, it is more preferable that there is a residual compressive stress of 1000 MPa or more over the entire surface of the rod main body 10.
  • the shot material fine metal particles or fine non- metal particles having a diameter of 500 ⁇ . m or less
  • the shot material is accelerated to about 200 m/s, and allowed to collide against the surface of the workpiece. Through adjustment of the shot pressure, the velocity of the shot material is controlled as appropriate.
  • step S6 the workpiece is polished.
  • the inner peripheral surface 22a of the piston pin hole 22 and the inner peripheral surface 32a of the crankpin hole 32 are polished. In this manner, the connecting rod 1 is completed.
  • a workpiece which is made of a steel containing no less than 0.1wt% and no more than 0.45wt% of carbon is subjected to a plural number of rounds of carburization treatment, in an ambient atmosphere having a carbon potential of 0.9% or more (steps S3 and S4) .
  • a high-concentration carburization treatment is performed.
  • a fine- particle shot peening is performed for the workpiece which has been subjected to the high-concentration carburization treatment (step S5) . Through this fine-particle shot peening, a residual compressive stress as large as 1000 MPa or more can be conferred to the surface of the workpiece.
  • a workpiece which is made of a steel containing 10 wtppm or less of oxygen and 0.01wt% or less of sulfur is provided.
  • the inclusions 4 whose circumcircle diameters have the possibility of growing to 10 ⁇ m or more are oxide and sulfide.
  • the circumcircle diameters of the oxide and sulfide in the surface vicinity of the completed connecting rod 1 are ensured to be 10 ⁇ m or less. Namely, it is ensured that no inclusions 4 whose circumcircle diameters exceed 10 ⁇ m exist in the surface vicinity of the rod main body 10.
  • the carbon potential of the ambient atmosphere when performing a second round of carburization treatment is 1.2% or less, so that the circumcircle diameter of the carbide 3 in the surface vicinity of the completed connecting rod 1 is ensured to be 10 ⁇ m or less.
  • carbide 3 is allowed to deposit in the surface vicinity with an increased certainty, thus making it possible to sufficiently obtain the effects of the high-concentration carburization treatment.
  • the carbon potential of the ambient atmosphere when performing the second round of carburization treatment can be regarded as substantially equal to the carbon concentration at a depth of 0.1 mm from the surface of the completed connecting rod 1. Therefore, since the carbon concentration at the depth of 0.1 mm from the surface of the rod main body 10 is no less than 0.9wt% and no more than 1.2wt%, it is possible to ensure that the circumcircle diameter of the carbide 3 is 10 ⁇ m or less, while sufficiently obtaining the effects of the high- concentration carburization treatment.
  • a fine-particle shot peening is performed in addition to a high-concentration carburization treatment, so that a connecting rod 1 whose connecting rod main body 10 has an excellent mechanical strength and which is suitable for weight reduction is produced.
  • Table 1 shows, regarding connecting rods 1 (Examples 1 to 4) which were actually produced by the production method according to the present embodiment, a relationship between the carbon potential (CP) of the ambient atmosphere in the second round of carburization treatment, the oxygen content and sulfur content in the steel, the circumcircle diameter Dl of the carbide 3 and the circumcircle diameters D2 of the inclusions 4 (oxide and sulfide) .
  • CP carbon potential
  • the first round of carburization treatment was performed at 910 °C to 930 °C for 300 minutes
  • the second round of carburization treatment was performed at 850 °C to 920 °C for 150 minutes.
  • the fine-particle shot peening was performed at a shot pressure of 0.5 MPa for 30 seconds, where fine particles made of high speed steel SKH59 having an average diameter of 45 ⁇ m were used as the shot material.
  • Table 1 also shows similar data of connecting rods (Comparative Examples 1 to 5) which were produced by production methods differing from the present embodiment with respect to at least one of the carbon potential, the oxygen content, and the sulfur content.
  • FIG. 5 shows results of measuring fatigue strength with respect to Examples 1 to 4 and Comparative Examples 1 to 5.
  • FIG. 5 is a graph, when performing a bending fatigue test for actual parts with respect to Examples 1 to 4 and Comparative Examples 1 to 5, showing a relationship between a number N of repetitions of bending until reaching breakage and a stress amplitude ⁇ a.
  • FIG. 5 also shows results of measuring fatigue strength with respect to connecting rods which were produced by the conventional production method described with reference to FIG. 8.
  • FIG. 1 illustrates a connecting rod 1 of a so-called integral type as an example, the present invention is not limited thereto.
  • the present invention is also suitably used for a connecting rod of a so-called split- type, in which the big end is split into two.
  • the carburization treatment may be performed any plural number of times; as described in Patent Literature 1, the carburization treatment may be performed three times or more.
  • the carbon potential in the last round of carburization treatment is set to no less than 0.9% and no more than 1.2%.
  • the connecting rod 1 according to the present embodiment is suitably used for the internal combustion engines of various transportation apparatuses, such as a car, a motorbike, a bus, a truck, a tractor, an airplane, a motorboat, and a vehicle for civil engineering use.
  • FIG. 6 shows an exemplary internal combustion engine 100 having the connecting rod 1 according to the present embodiment.
  • the internal combustion engine 100 includes a crankcase 110, a cylinder block 120, and a cylinder head 130.
  • a crankshaft 111 is accommodated in the crankcase 110.
  • the crankshaft 111 has a crankpin 112 and a crankweb 113.
  • a cylinder block 120 is provided above the crankcase 110.
  • a cylinder sleeve 121 having a cylindrical shape is fitted within the cylinder block 120, such that a piston 122 is allowed to reciprocate inside the cylinder sleeve 121.
  • a cylinder head 130 is provided above the cylinder block 120. In conjunction with the piston 122 and the cylinder sleeve 121 in the cylinder block 120, the cylinder head 130 define a combustion chamber 131.
  • the cylinder head 130 has an intake port 132 and an exhaust port 133.
  • An intake valve 134 for supplying vapor to the interior of the combustion chamber 131 is provided within the intake port 132, and an exhaust valve 135 for enabling evacuation of the combustion chamber 131 is provided within the exhaust port 133.
  • the piston 122 and the crankshaft 111 are linked via the connecting rod 1. Specifically, a piston pin 123 of the piston 122 is inserted in a piston pin hole which is formed in the small end 20 of the connecting rod 1, and the crankpin 112 of the crankshaft 111 is inserted in a crankpin hole which is formed in the big end 30, thus linking the piston 122 and the crankshaft 111.
  • a roller bearing (rolling bearing) 114 is provided between the inner peripheral surface of the crankpin hole and the crankpin 112.
  • the connecting rod 1 according to the present embodiment is suitable for weight reduction, the internal combustion engine 100 having the connecting rod 1 according to the present embodiment has an improved response. Since the weight of the connecting rod 1 is reduced, the weight of a reciprocating portion in the internal combustion engine 100 is reduced, so that primary vibration (vibration which occurs due to reciprocation of the reciprocating portion including the piston 120 and the connecting rod 1, with a cycle of one per rotation of the crankshaft 111) can be reduced. Furthermore, the connecting rod 1 according to the present embodiment has an excellent fatigue strength, and therefore the reliability of the internal combustion engine 100 is also improved .
  • FIG. 7 shows a motorcycle having the internal combustion engine 100 shown in FIG. 6.
  • a head pipe 302 is provided at the front end of a body frame 301.
  • front forks 303 are attached so as to be capable of swinging in the right- left direction of the vehicle.
  • a front wheel 304 is supported so as to be capable of rotating.
  • a seat rail 306 is attached at an upper portion of the rear end of the body frame 301 so as to extend in the rear direction.
  • a fuel tank 307 is provided on the body frame 301, and a main seat 308a and a tandem seat 308b are provided on the seat rail 306.
  • Rear arms 309 extending in the rear direction are attached to the rear end of the body frame 301. At the rear end of the rear arms 309, a rear wheel 310 is supported so as to be capable of rotating.
  • the internal combustion engine 100 shown in FIG. 6 is held.
  • the internal combustion engine 100 includes the connecting rod 1 according to the present embodiment.
  • a radiator 311 is provided in front of the internal combustion engine 100.
  • An exhaust pipe 312 is connected to an exhaust port of the engine 100, and a muffler 313 is attached to the rear end of the exhaust pipe 312.
  • a transmission 315 is linked to the internal combustion engine 100.
  • Driving sprockets 317 are attached on an output axis 316 of the transmission 315. Via a chain 318, the driving sprockets 317 are linked to rear wheel sprockets 319 of the rear wheel 310.
  • the transmission 315 and the chain 318 function as a transmitting mechanism for transmitting the motive power generated in the internal combustion engine 100 to the driving wheel.
  • a connecting rod whose rod main body has a good mechanical strength and which is suitable for weight reduction, as well as a production method thereof.
  • the connecting rod according to the present invention is suitably used for various types of internal combustion engines (e.g., an engine for a transportation apparatus) .

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
  • Heat Treatment Of Articles (AREA)

Abstract

L'invention concerne une bielle, dont le corps principal de bielle présente une bonne résistance mécanique, qui est appropriée pour une réduction de poids, ainsi qu’un procédé de fabrication de celle-ci. Une bielle selon la présente invention comprend : un corps principal de bielle et un pied de bielle et une tête de bielle disposée à une extrémité et à une autre extrémité du corps principal de bielle, la bielle étant faite d’acier. Une contrainte de compression résiduelle dans au moins une partie de la surface du corps principal de bielle est d’au moins 1 000 MPa. Des diamètres de cercle circonscrit de carbure et d'inclusions contenus dans le voisinage d'une surface du corps principal de bielle sont d’au plus 10 µm chacun.
PCT/JP2009/069993 2008-12-19 2009-11-19 Bielle, moteur à combustion interne, appareil de transport et procédé de fabrication de bielle WO2010071014A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2011518617A JP5433692B2 (ja) 2008-12-19 2009-11-19 コネクティングロッド、内燃機関、輸送機器およびコネクティングロッドの製造方法

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2008323177 2008-12-19
JP2008-323177 2008-12-19

Publications (1)

Publication Number Publication Date
WO2010071014A1 true WO2010071014A1 (fr) 2010-06-24

Family

ID=41697784

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2009/069993 WO2010071014A1 (fr) 2008-12-19 2009-11-19 Bielle, moteur à combustion interne, appareil de transport et procédé de fabrication de bielle

Country Status (2)

Country Link
JP (1) JP5433692B2 (fr)
WO (1) WO2010071014A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114633218A (zh) * 2022-03-04 2022-06-17 贵州捷盛钻具股份有限公司 一种钎杆的表面处理方法、表面处理装置及钎杆制造方法

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5084116A (en) * 1989-07-31 1992-01-28 Nippon Seiko Kabushiki Kaisha Rolling contact element steel and rolling bearing made thereof
US6655026B1 (en) * 1999-01-28 2003-12-02 Honda Giken Kogyo Kabushiki Kaisha Production process for connecting rod for internal combustion engine
EP1538352A1 (fr) * 2003-12-02 2005-06-08 Yamaha Hatsudoki Kabushiki Kaisha Bielle à tête fracturée, moteur et vehicule
US20060130935A1 (en) * 2004-12-10 2006-06-22 Daido Stell Co., Ltd. & Honda Moto Co., Ltd. Carburized component and method of manufacturing the same
JP2008255470A (ja) * 2007-03-12 2008-10-23 Honda Motor Co Ltd 低サイクル疲労特性に優れた浸炭部品

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4518922B2 (ja) * 2003-12-02 2010-08-04 ヤマハ発動機株式会社 分割型コンロッド、エンジンおよび車両

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5084116A (en) * 1989-07-31 1992-01-28 Nippon Seiko Kabushiki Kaisha Rolling contact element steel and rolling bearing made thereof
US6655026B1 (en) * 1999-01-28 2003-12-02 Honda Giken Kogyo Kabushiki Kaisha Production process for connecting rod for internal combustion engine
EP1538352A1 (fr) * 2003-12-02 2005-06-08 Yamaha Hatsudoki Kabushiki Kaisha Bielle à tête fracturée, moteur et vehicule
US20060130935A1 (en) * 2004-12-10 2006-06-22 Daido Stell Co., Ltd. & Honda Moto Co., Ltd. Carburized component and method of manufacturing the same
JP2008255470A (ja) * 2007-03-12 2008-10-23 Honda Motor Co Ltd 低サイクル疲労特性に優れた浸炭部品

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114633218A (zh) * 2022-03-04 2022-06-17 贵州捷盛钻具股份有限公司 一种钎杆的表面处理方法、表面处理装置及钎杆制造方法
CN114633218B (zh) * 2022-03-04 2023-09-19 贵州捷盛钻具股份有限公司 一种钎杆的表面处理方法、表面处理装置及钎杆制造方法

Also Published As

Publication number Publication date
JP2012512992A (ja) 2012-06-07
JP5433692B2 (ja) 2014-03-05

Similar Documents

Publication Publication Date Title
KR100961584B1 (ko) 침탄 고주파 담금질 부품
JP5306795B2 (ja) コンロッド、内燃機関、輸送機器およびコンロッドの製造方法
RU2650466C2 (ru) Стальная труба для топливопровода высокого давления и использующий ее топливопровод высокого давления
JP4352261B2 (ja) 歯車
WO2015098106A1 (fr) Procédé de production de constituant en acier cémenté et constituant en acier cémenté
US8479704B2 (en) Sliding component for internal combustion engine, internal combustion engine, transporter, and method for producing the sliding component for internal combustion engine
JP5669339B2 (ja) 高強度浸炭部品の製造方法
WO2019244503A1 (fr) Composant mécanique
JP4188307B2 (ja) 浸炭部品及びその製造方法
JPH0625823A (ja) 耐ピッチング性に優れた浸炭鋼部品
JP6601358B2 (ja) 浸炭部品およびその製造方法
WO2010071014A1 (fr) Bielle, moteur à combustion interne, appareil de transport et procédé de fabrication de bielle
JP5342655B2 (ja) コネクティングロッドおよびそれを備えた単気筒内燃機関ならびに鞍乗型車両
JP5603889B2 (ja) 鋼製部品、単気筒内燃機関、鞍乗型車両および鋼製部品の製造方法
JP2021167444A (ja) 圧縮コイルばね
WO2019244504A1 (fr) Procédé de production de composants de machine
US11788162B2 (en) Manufacturing method of cage and the cage manufactured by the method
EP3015723B1 (fr) Bielle, moteur à combustion interne, véhicule automobile et procédé de production de bielle
JP5744000B2 (ja) 内燃機関用摺動部品、内燃機関、輸送機器および内燃機関用摺動部品の製造方法
JP2003277882A (ja) 鉄合金部品およびその製造方法
JPH10147814A (ja) 熱処理歪みの少ない肌焼鋼製品の製法
JP2010151218A (ja) コンロッド、内燃機関、輸送機器およびコンロッドの製造方法
JP4870922B2 (ja) コンロッド、エンジン、自動車両およびコンロッドの製造方法
JPH09235651A (ja) 耐磨耗性材料及び耐磨耗性機械部品
JP2012255551A (ja) コンロッドの製造方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09768248

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2011518617

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 09768248

Country of ref document: EP

Kind code of ref document: A1