JPH0668134B2 - High-strength connectein rod manufacturing method - Google Patents
High-strength connectein rod manufacturing methodInfo
- Publication number
- JPH0668134B2 JPH0668134B2 JP20561986A JP20561986A JPH0668134B2 JP H0668134 B2 JPH0668134 B2 JP H0668134B2 JP 20561986 A JP20561986 A JP 20561986A JP 20561986 A JP20561986 A JP 20561986A JP H0668134 B2 JPH0668134 B2 JP H0668134B2
- Authority
- JP
- Japan
- Prior art keywords
- connecting rod
- strength
- large end
- induction
- boundary
- Prior art date
- Legal status (The legal status 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 status listed.)
- Expired - Fee Related
Links
Landscapes
- Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)
- Heat Treatment Of Articles (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は高強度コネクティングロッドと製造法に関する
ものである。The present invention relates to a high strength connecting rod and a manufacturing method.
コネクティングロッドはピストンとクランクシャフトを
連結する棒で、ピストンの往復運動をクランクシャフト
に伝え、かつクランクシャフトとともにピストン往復運
動を回転運動に変える作用をする。そのため、エンジン
作動時の応力分布を示す第６図からもわかるように、大
端部６の肩部すなわち大端部６とコラム部３との境の側
面部分、大端部６の油穴７及び小端部２の肩すなわち小
端部２とコラム部３の境の側面部分に最も応力が集中す
る。したがって、コネクティングロッドは、特に、該部
分に高強度が要求されている。従来、コネクティングロ
ッドは、機械加工したのち、全面に高周波焼き入れして
強化している（特開昭59-89720号参照）。The connecting rod is a rod that connects the piston and the crankshaft, and transmits the reciprocating motion of the piston to the crankshaft and converts the reciprocating motion of the piston into rotary motion together with the crankshaft. Therefore, as can be seen from FIG. 6 showing the stress distribution when the engine is operating, the shoulder portion of the large end portion 6, that is, the side surface portion of the boundary between the large end portion 6 and the column portion 3, the oil hole 7 of the large end portion 6 is formed. Further, the stress is most concentrated on the shoulder of the small end portion 2, that is, the side surface portion at the boundary between the small end portion 2 and the column portion 3. Therefore, the connecting rod is required to have high strength especially in the portion. Conventionally, the connecting rod is machined and then induction-hardened to strengthen the entire surface (see Japanese Patent Laid-Open No. 59-89720).
しかしながら、上記したように、コネクティングロッド
の全面に高周波焼き入れすると、焼き入れしないものに
比べて疲労高度が向上するが、かなりの量のひずみが発
生するので、大端部６にキャップ11を嵌めたとき、大端
部６とキャップ11にずれが生じてしまう。そのため、ク
ランクとの摺動性を良好に保持するために大端部６のク
ランクピンとの摺動部12を研削する工程が必要となると
いう問題がある。図中、９はナット、10はボルトを示
す。However, as described above, when induction hardening is performed on the entire surface of the connecting rod, the fatigue level is improved as compared with the case where no hardening is performed, but a considerable amount of strain is generated, so that the cap 11 is fitted to the large end portion 6. When this happens, the large end 6 and the cap 11 are misaligned. Therefore, there is a problem that a step of grinding the sliding portion 12 of the large end portion 6 with the crank pin is required in order to maintain good slidability with the crank. In the figure, 9 indicates a nut and 10 indicates a bolt.
また、第７図に示すように油穴７の内部に焼き入れ部13
との境いの焼境部14に発生した引張り応力により大幅な
強度向上を図れず、該焼境部を有する油穴で破断しやす
いという問題がある。In addition, as shown in FIG.
There is a problem in that the tensile stress generated in the boundary portion 14 between the boundary and the boundary portion cannot significantly improve the strength, and the oil hole having the boundary portion easily breaks.
本発明は上記問題点を解決するためのもので、強度の優
れたコネクティングロッドの製造法を提供することを目
的とするものである。The present invention is intended to solve the above problems, and an object thereof is to provide a method for manufacturing a connecting rod having excellent strength.
本発明の高強度コネクティングロッドの製造法は、コネ
クティングロッドの製造において、所定形状に機械加工
後、コネクティングロッドの大端部と小端部の、油穴が
存在しない肩部を高周波焼き入れし、その後、コネクテ
ィングロッド全面にショットピーニングを施すことを特
徴とするものである。The manufacturing method of the high-strength connecting rod of the present invention is, in the manufacturing of the connecting rod, after machining into a predetermined shape, the large end portion and the small end portion of the connecting rod are induction-hardened at the shoulder portion where no oil hole exists, After that, shot peening is performed on the entire surface of the connecting rod.
本発明において、高周波焼き入れする大端部と小端部の
肩部は、大端部とコラム部との境の側面部分及び小端部
とコラム部との境の側面部分で、油穴が存在する部分
は、焼き入れすると、油穴内部に焼境部ができ、そこか
ら破断しやすくなるため、焼き入れしない。In the present invention, the shoulders of the large end and the small end to be induction hardened are the side surface part of the boundary between the large end part and the column part and the side surface part of the boundary between the small end part and the column part. If the existing portion is hardened by quenching, a hardened portion is formed inside the oil hole, and it is easy to break from it, so do not quench.
油穴は、従来、応力の集中する大端部とコラム部との境
の側面部分から大端部の摺動部へかけて設けているが、
比較的応力の集中しないコンロッドボルト近傍から大端
部の摺動部へかけて設けることが好ましい。Conventionally, the oil hole is provided from the side surface part of the boundary between the large end where the stress is concentrated and the column part to the sliding part of the large end,
It is preferable to provide from the vicinity of the connecting rod bolt where the stress is not relatively concentrated to the sliding portion of the large end.
ショットピーニングする際、ショット粒は、油穴をショ
ットピーニングできるように、油穴を通過することがで
きる径を有するものを用いることが必要である。During shot peening, it is necessary to use shot particles having a diameter that allows them to pass through the oil holes so that the oil holes can be shot peened.
本発明の高強度コネクティングロッドの製造法は、応力
手中部位である大端部と小端部の肩部、すなわち大端部
とコラム部との境の側面部分及び小端部とコラム部との
境の側面部分を高周波焼き入れするため、硬化し、強度
が向上する。油穴のある肩部は高周波焼き入れしないた
め、油穴内部に破断しやすい焼境部ができない。そして
高周波焼き入れしたのち、コネクティングロッド全面に
ショットピーニング処理を施すため、油穴も含めて全面
に残留応力を付与することができ、強度が向上する。The manufacturing method of the high-strength connecting rod of the present invention is a shoulder portion between the large end and the small end, which is a stress-increasing portion, that is, the side portion on the boundary between the large end and the column portion, and the small end and the column portion. Since the side surface of the boundary is induction hardened, it hardens and the strength is improved. Since the shoulder with oil holes is not induction hardened, there is no easy-to-be-broken boundary inside the oil holes. Then, after induction hardening, shot peening is applied to the entire surface of the connecting rod, so that residual stress can be applied to the entire surface including the oil holes, and the strength is improved.
機械加工して得た、第１図に示すような、大端穴径46mm
を有するコネクティングロッド（ＪＩＳ Ｓ50Ｃ焼き入
れ戻し品）１の小端部２とコラム部３との境の側面部分
である小端部の肩部４，５及び大端部６とコラム部３と
の境の側面部分で油穴７のない大端部の肩部８に高周波
焼き入れ装置のヘアピンコイル（図示略）を近づけ、周
波数100KHz、電力1.2Kw/cm2で５秒間該部分を加熱（900
℃）した後、直ちに水溶性焼き入れ液30／minを噴射
させて焼き入れを行った。その結果、焼き入れ深さ２〜
3.5mm、最表面硬さHv680〜750が得られた。次いでイン
ペラータイプのショット機にて、硬さHRC53、粒径0.6mm
のショット粒を速度90m/sで50秒間、上記の高周波焼き
入れしたコネクティングロッド１の全面に投射してショ
ットピーニングした。アークハイトは0.52、カバーレン
ジは98％以上であった。油穴７内部もショットピーニン
グしたが、小端部２のピストンピンとの摺動部及び大端
部６のクランクピンとの摺動部は、面粗度を劣化させな
いためにマスキングを施した。なお、油穴７は、応力が
集中する大端部６とコラム部３との境からはずして、コ
ンロッドボルト10よりに設けた。図中、９はナット、11
はキャップを示す。Large end hole diameter 46mm obtained by machining as shown in Fig. 1.
Of the connecting rod (JIS S50C tempered product) 1 having the shoulders 4 and 5 at the small end which is the side surface of the boundary between the small end 2 and the column 3 and the large end 6 and the column 3. Bring the hairpin coil (not shown) of the induction hardening device close to the shoulder 8 at the large end where there is no oil hole 7 on the side of the boundary, and heat the part for 5 seconds at a frequency of 100 KHz and power of 1.2 Kw / cm 2 (900
Immediately after the heating, a water-soluble quenching liquid of 30 / min was sprayed to quench it. As a result, quenching depth 2
3.5 mm and outermost surface hardness Hv680-750 were obtained. Next, with an impeller type shot machine, hardness H R C53, particle size 0.6 mm
Shot peening was performed for 50 seconds at a speed of 90 m / s on the entire surface of the above-described induction-hardened connecting rod 1. The arc height was 0.52 and the coverage was over 98%. The inside of the oil hole 7 was also shot peened, but the sliding portion of the small end 2 with the piston pin and the sliding portion of the large end 6 with the crank pin were masked in order not to deteriorate the surface roughness. The oil hole 7 is provided on the connecting rod bolt 10 so as to be removed from the boundary between the large end portion 6 where the stress is concentrated and the column portion 3. In the figure, 9 is a nut, 11
Indicates a cap.
上記のようにして処理したコネクティングロッドの残留
応力分布を第２図に示す。非高周波焼き入れ部分の残留
応力は表面から0.2〜0.3mmの部分が最高で54Kg/mm2が得
られ、高周波焼き入れ部分の残留応力は表面から0.1〜
0.2mmの部分が最高で74Kg/mm2が得られ、非高周波焼き
入れ部分より大きく、また、ショットピーニング前に比
して表面から0.4mmの深さまで残留応力が向上した。The residual stress distribution of the connecting rod treated as described above is shown in FIG. The maximum residual stress in the non-induction hardened part is 0.2 to 0.3 mm from the surface, and the maximum residual stress is 54 Kg / mm 2.
A maximum of 74 kg / mm 2 was obtained in the 0.2 mm portion, which was larger than in the non-induction hardened portion, and the residual stress was improved to a depth of 0.4 mm from the surface compared to before shot peening.
上記で得たコネクティングロッドの疲労強度、大端部と
キャップのくいちがい量及び面粗さRzを調べた。比較例
１として機械加工後のコネクティングロッド、比較例２
として機械加工後全面高周波焼き入れしたコネクティン
グロッド及び比較例３としてショットピーニングを除い
て実施例と同様に局部高周波焼き入れしたコネクティン
グロッドを実施例と同様に疲労強度、くいちがい量及び
面粗さRzを調べた。結果を実施例と併せてそれぞれ第３
図、第４図(b)、第５図に示す。なお、評価は、機械共
振式の疲労試験機を用いて行なった。くいちがい量は第
４図(a)に示すように大端部６とキャップ11を合わせた
ときの両側端のずれを合計したもので、大端部のひずみ
により生じるものである。面粗さRzはコネクティングロ
ッド本体のコラム部側面を測定した。The fatigue strength of the connecting rod obtained above, the amount of disengagement of the large end and the cap, and the surface roughness Rz were examined. As Comparative Example 1, the connecting rod after machining, Comparative Example 2
As for the connecting rod that was induction hardened on the entire surface after machining and as Comparative Example 3 the connecting rod that was locally induction hardened in the same manner as in the example except for shot peening, the fatigue strength, the amount of scratches and the surface roughness Rz were the same as in the example. Examined. The results are combined with the results in the third example.
It is shown in Fig. 4, Fig. 4 (b) and Fig. 5. The evaluation was performed using a mechanical resonance type fatigue tester. As shown in FIG. 4 (a), the amount of staggering is the total deviation of both ends when the large end portion 6 and the cap 11 are combined, and is caused by the distortion of the large end portion. The surface roughness Rz was measured on the side surface of the column portion of the connecting rod body.
疲労強度は第３図に示すように、機械加工の後の比較例
１が1.5トン、全面に高周波焼き入れした比較例２が2.4
トン、局部高周波焼き入れした比較例３が1.9トンに対
し、実施例は3.1トンと優れていた。比較例１の破断位
置は応力の集中する小端部とコラム部との境及び油穴で
あった。比較例２は比較例１に比して60％強度が向上し
たが第４図(b)に示すようにひずみが許容値（20〜25
μ）を越えている。この破断位置は油穴内部の焼境部で
あった。比較例３は局部的な高周波焼き入れであるた
め、大きなひずみを発生させずに26％の強度向上が図れ
た。これは焼き入れによると硬化と、油穴の位置を応力
集中のないコンロッド寄りにし、油穴に焼き入れしなか
ったため焼境部ばできなかったことによると考えられ
る。この場合は高周波焼き入れを施していないコラム部
と油穴で破断した。本実施例は油穴を除いて応力の集中
する部位に局部高周波焼き入れし、更にショットピーニ
ングによって油穴とコラム部の非高周波焼き入れ部分の
強化はもちろん、焼き入れ部分をもより一層強化するこ
とができ、比較例１に対して106％もの強度向上が図れ
た。また、くいちがい量は第５図に示すように全面に高
周波焼き入れした比較例２が39μであるのに対して、実
施例は比較例１の10μ、比較例３の12μとほぼ同程度の
13μに抑えることができ、大端部のクランクとの摺動部
を研削する必要がない。面粗さRzは比較例１，２及び３
が66.5μであり、実施例は68μと、比較例１，２及び３
に比べてほとんど増大していなく、問題はない。As shown in FIG. 3, the fatigue strength of Comparative Example 1 after machining was 1.5 tons, and that of Comparative Example 2 in which induction hardening was applied to the entire surface was 2.4.
The comparative example 3 which was locally induction hardened was 1.9 tons, while the example was excellent at 3.1 tons. The breakage position of Comparative Example 1 was the boundary between the small end where the stress is concentrated and the column, and the oil hole. In Comparative Example 2, the strength was improved by 60% as compared with Comparative Example 1, but as shown in Fig. 4 (b), the strain was within the allowable value (20-25
μ) is exceeded. This rupture position was a burning boundary inside the oil hole. Since Comparative Example 3 is a local induction hardening, it was possible to improve the strength by 26% without generating a large strain. It is considered that this is because hardening caused by hardening and that the oil hole was located closer to the connecting rod where stress concentration was not concentrated, and the oil could not be hardened in the oil hole because the oil hole was not hardened. In this case, fracture occurred at the column and oil holes that were not induction hardened. In the present embodiment, local induction hardening is performed on a portion where stress is concentrated except for the oil hole, and further, the shot peening strengthens the non-induction hardening portion of the oil hole and the column portion, and further strengthens the hardening portion. It was possible to improve the strength by 106% as compared with Comparative Example 1. Further, the amount of stirrup is 39 μ in Comparative Example 2 in which induction hardening is performed on the entire surface as shown in FIG. 5, whereas in Example, it is about 10 μ in Comparative Example 1 and 12 μ in Comparative Example 3.
It can be suppressed to 13μ, and there is no need to grind the sliding part with the crank at the large end. Surface roughness Rz is Comparative Examples 1, 2 and 3
Is 66.5μ, the example is 68μ, and Comparative Examples 1, 2 and 3
Compared to, there is almost no increase and there is no problem.
本発明の高強度コネクティングロッドの製造法は、上記
したように応力集中部位に局部高周波焼き入れし、全面
にショットピーニングするため、大きなひずみを生じ
ず、しかも面粗さも大きくさせずに高強度コネクティン
グロッドを製造することができる。その結果、従来必要
であった、大端部のクランクピンとの摺動部の研削工程
が不要となった。The manufacturing method of the high-strength connecting rod of the present invention is, as described above, locally induction-hardened at the stress-concentrated portion and shot-peened on the entire surface, so that large strain is not generated, and high-strength connecting without increasing surface roughness. The rod can be manufactured. As a result, the grinding process of the sliding part with the crank pin at the large end, which was required in the past, is no longer necessary.
第１図は本発明の一実施例のコネクティングロッドの上
面図、 第２図は本発明の一実施例のコネクティングロッドの残
留応力分布図、 第３図は本発明の一実施例のコネクティングロッドの疲
労強度を示すグラフ、 第４図(a)は本発明の一実施例のコネクティングロッド
の大端部とキャップのくいちがい量の測定を説明する
図、第４図(b)は本発明の一実施例のコネクティングロ
ッドの大端部とキャップのくいちがい量を示すグラフ、 第５図は本発明の一実施例のコネクティングロッドの面
粗さRzを示すグラフを表わす。 第６図はエンジン作動時のコネクティングロッドの応力
分布図、 第７図は従来の全面高周波焼き入れしたコネクティング
ロッドの油穴部断面図を表わす。 図中、 １…コネクティングロッド、２…小端部 ３…コラム部、４，５，８…肩部 ６…大端部、７…油穴 11…キャップ1 is a top view of a connecting rod of one embodiment of the present invention, FIG. 2 is a residual stress distribution diagram of the connecting rod of one embodiment of the present invention, and FIG. 3 is a connecting rod of one embodiment of the present invention. Fig. 4 (a) is a graph showing the fatigue strength, Fig. 4 (a) is a diagram for explaining the measurement of the amount of disengagement between the large end portion of the connecting rod and the cap, and Fig. 4 (b) is one embodiment of the present invention. FIG. 5 is a graph showing the large amount of the connecting rod of the example and the amount of squeezing of the cap, and FIG. 5 is a graph showing the surface roughness Rz of the connecting rod of the embodiment of the present invention. FIG. 6 is a stress distribution diagram of the connecting rod when the engine is operating, and FIG. 7 is a sectional view of the oil hole of the conventional connecting rod which has been induction hardened. In the figure, 1 ... connecting rod, 2 ... small end part 3 ... column part, 4, 5, 8 ... shoulder part 6 ... large end part, 7 ... oil hole 11 ... cap
Claims (1)
定形状に機械加工後、コネクティングロッドの大端部と
小端部の、油穴が存在しない肩部を高周波焼き入れし、
その後、コネクティングロッド全面にショットピーニン
グを施すことを特徴とする高強度コネクティングロッド
の製造法。1. In manufacturing a connecting rod, after machining into a predetermined shape, the large and small ends of the connecting rod are induction-hardened at the shoulders without oil holes,
After that, a method for manufacturing a high-strength connecting rod, characterized by subjecting the entire connecting rod to shot peening.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20561986A JPH0668134B2 (en) | 1986-09-01 | 1986-09-01 | High-strength connectein rod manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20561986A JPH0668134B2 (en) | 1986-09-01 | 1986-09-01 | High-strength connectein rod manufacturing method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6362820A JPS6362820A (en) | 1988-03-19 |
| JPH0668134B2 true JPH0668134B2 (en) | 1994-08-31 |
Family
ID=16509879
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20561986A Expired - Fee Related JPH0668134B2 (en) | 1986-09-01 | 1986-09-01 | High-strength connectein rod manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0668134B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1450056B1 (en) * | 2003-02-19 | 2017-06-07 | Nissan Motor Co., Ltd. | High-strength connecting rod and method of producing same |
| JP7352506B2 (en) * | 2020-04-01 | 2023-09-28 | 日産自動車株式会社 | Internal combustion engine link members |
-
1986
- 1986-09-01 JP JP20561986A patent/JPH0668134B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6362820A (en) | 1988-03-19 |
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