JPH06329056A - Crawler bushing and method of manufacturing the same - Google Patents
Crawler bushing and method of manufacturing the sameInfo
- Publication number
- JPH06329056A JPH06329056A JP14253993A JP14253993A JPH06329056A JP H06329056 A JPH06329056 A JP H06329056A JP 14253993 A JP14253993 A JP 14253993A JP 14253993 A JP14253993 A JP 14253993A JP H06329056 A JPH06329056 A JP H06329056A
- Authority
- JP
- Japan
- Prior art keywords
- bushing
- hardness
- peripheral surface
- outer peripheral
- hardened layer
- 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.)
- Granted
Links
Landscapes
- Heat Treatment Of Articles (AREA)
Abstract
(57)【要約】
【目的】 疲労強度などが高品質な履帯用ブッシングを
安価に提供する。
【構成】 ブッシング（１）の外周面（１ａ）および内
周面（１ｂ）から肉厚心部（１ｃ）に向かって、それぞ
れ高周波焼入れによる硬化層が形成されていると共に、
両硬化層の間の肉厚心部（１ｃ）には、高周波焼入れ前
の圧延素材、焼なまし素材および焼ならし素材などの硬
さが残存した素地部を有しており、断面Ａ−Ａ間で測定
した内外周面間の硬さ分布が略Ｕ字形である。
(57) [Summary] [Purpose] To provide a high-quality track bushing at low cost. A hardened layer is formed by induction hardening from the outer peripheral surface (1a) and the inner peripheral surface (1b) of the bushing (1) toward the thick core portion (1c), respectively, and
The thick core portion (1c) between both hardened layers has a base material in which the hardness of a rolled material, annealed material and a normalized material before induction hardening remains, and has a cross section A- The hardness distribution between the inner and outer peripheral surfaces measured between A is approximately U-shaped.
Description
【０００１】[0001]
【産業上の利用分野】本発明は、履帯用ブッシングおよ
びその製造方法に係わり、特に建設機械などの機械的特
性が要求される部位に適用するに好適な履帯用ブッシン
グおよびその製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crawler bushing and a manufacturing method thereof, and more particularly to a crawler bushing suitable for application to a portion of a construction machine or the like where mechanical characteristics are required and a manufacturing method thereof.
【０００２】[0002]
【従来の技術】従来、建設機械などに使用され、耐摩耗
性、強度など機械的特性が要求される履帯用ブッシング
あるいはその製造方法は次のものが知られている。 （イ）中炭素低合金鋼の圧延素材に機械加工などを施
し、電気炉などで約８５０℃加熱後油焼入れを行い、次
に６００℃前後で焼戻しを行うことで、履帯用ブッシン
グ粗加工材の素地硬さをロックウェル硬さのＣスケ−ル
ＨＲＣで３０程度に調整している。その後、外周面およ
び内周面にそれぞれ高周波焼入れを施し、履帯用ブッシ
ング粗加工材の内外周側に硬さＨＲＣが４５程度以上の
硬化層を形成させ、内部の肉厚心部は前記焼戻しの硬さ
を維持した素地硬さ部である。次に電気炉などで２００
℃程度の低温焼戻しを行い、仕上げ加工を施して履帯用
ブッシングとする。2. Description of the Related Art Conventionally, the following is known as a crawler bushing or its manufacturing method, which is used in construction machines and is required to have mechanical properties such as wear resistance and strength. (B) A medium-carbon low-alloy steel rolled material is machined, heated in an electric furnace at about 850 ° C, oil-quenched, and then tempered at around 600 ° C to make a rough-processed bushing material for tracks. The base hardness of is adjusted to about 30 with the C scale HRC of Rockwell hardness. After that, induction hardening is applied to the outer peripheral surface and the inner peripheral surface, respectively, to form a hardened layer having a hardness HRC of about 45 or more on the inner and outer peripheral sides of the roughened material of the bushing for a crawler belt. It is a base hardness part that maintains hardness. Next, 200 in an electric furnace
It is tempered at a low temperature of about ℃ and finished to make a bushing for tracks.
【０００３】（ロ）ブッシングの外周面および内周面か
ら肉厚中心部に向かってそれぞれ高周波焼入れ部が形成
されており、両高周波焼入れ部の間の肉厚心部に、表面
硬化前の調質を施すことなく、焼戻し部が形成されてお
り、内外周面間の硬さ分布がほぼＶ字状となっている
（例えば、特公昭６３−１６３１４号公報）。(B) Induction-hardened portions are formed from the outer peripheral surface and the inner peripheral surface of the bushing toward the center of the wall thickness, respectively. A tempered portion is formed without applying quality, and the hardness distribution between the inner and outer peripheral surfaces is substantially V-shaped (for example, Japanese Patent Publication No. 63-16314).
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、上記従
来の履帯用ブッシングあるいはその製造方法には次のよ
うな問題点がある。すなわち、上記（イ）は、高周波焼
入れ前に調質を目的とする油焼入れと焼戻しとの２工程
があり、多大なエネルギ−と時間を要する。さらに、油
焼入れは、焼入れ時期、油の温度・汚れなど多くの管理
を必要とする。また、（ロ）は、調質の２工程が無いも
のの、外周面の高周波焼入れ時に内周面まで高温加熱を
するため、通常の方法の一つである（イ）に比して前記
加熱工程では大きなエネルギ−を必要とする。さらに、
履帯用ブッシングの肉厚が厚い場合には、エネルギ−の
点でより不経済となる。However, the above-mentioned conventional track bushing or the manufacturing method thereof has the following problems. That is, the above (a) has two steps of oil quenching and tempering for the purpose of tempering before induction hardening, which requires a great deal of energy and time. Further, oil quenching requires many controls such as quenching time, oil temperature and dirt. Further, (B) does not have two steps of tempering, but since the inner peripheral surface is heated at a high temperature during induction hardening of the outer peripheral surface, the heating step as compared with (A) which is one of the usual methods. Then, it requires a large amount of energy. further,
If the thickness of the track bushing is large, it becomes more economical in terms of energy.
【０００５】本発明は、上記従来技術の問題点に着目
し、調質工程を省略あるいは簡略化し、肉厚の厚い履帯
用ブッシングでも多大なエネルギを不要とし、かつ、機
械的特性等の品質が従来品と同等以上である履帯用ブッ
シングおよびその製造方法を提供することを目的とす
る。The present invention focuses on the above-mentioned problems of the prior art, omits or simplifies the refining process, does not require a large amount of energy even with a thick track bushing, and has a quality such as mechanical characteristics. It is an object of the present invention to provide a bushing for a crawler belt which is equal to or more than a conventional product and a manufacturing method thereof.
【０００６】[0006]
【課題を解決するための手段】上記目的を達成するため
に、本発明に係わる履帯用ブッシングにおいて、第１発
明は、ブッシング（１）の外周面（１ａ）および内周面
（１ｂ）から肉厚心部（１ｃ）に向かって、それぞれ高
周波焼入れによる硬化層が形成されていると共に、両硬
化層の間の肉厚心部（１ｃ）には、高周波焼入れ前の圧
延素材の硬さが残存した素地部（Ｌｍ）を有しており、
内外周面間の硬さ分布が略Ｕ字形であることを特徴とす
る。第２発明は、第１発明において、高周波焼入れ前の
圧延素材の硬さは、高周波焼入れ前の焼なまし素材ある
いは焼ならし素材の硬さである。第３発明は、第１発明
又は第２発明において、高周波焼入れにおける外周面
（１ａ）からの外周硬化層厚さ（Ｌｏ）と内周面（１
ｂ）からの内周硬化層厚さ（Ｌｉ）とを加えた硬化層厚
さは、ブッシング肉厚（Ｌ）に対して０．３５〜０．７
である。In order to achieve the above-mentioned object, in a crawler bushing according to the present invention, the first invention is that the outer peripheral surface (1a) and the inner peripheral surface (1b) of the bushing (1) are meat. Hardened layers are formed by induction hardening toward the thick core (1c), and the hardness of the rolled material before induction hardening remains in the thick core (1c) between both hardened layers. Has a base material (Lm)
The hardness distribution between the inner and outer peripheral surfaces is substantially U-shaped. In a second aspect based on the first aspect, the hardness of the rolled material before induction hardening is the hardness of the annealed material or the normalized material before induction hardening. A third invention is the first invention or the second invention, wherein the outer peripheral hardened layer thickness (Lo) from the outer peripheral surface (1a) and the inner peripheral surface (1
The hardened layer thickness including the inner hardened layer thickness (Li) from b) is 0.35 to 0.7 with respect to the bushing thickness (L).
Is.
【０００７】さらに、本発明に係わる履帯用ブッシング
の製造方法において、第４発明は、（イ）圧延素材をブ
ッシング粗加工材にする機械加工を施す第１工程、
（ロ）前記ブッシング粗加工材の外周面に高周波焼入れ
を施し、外周硬化層を形成すると共に、内周面側は圧延
素材の硬さである第２工程、（ハ）前記ブッシング粗加
工材の外周面を冷却しつつ、内周面に高周波焼入れを施
し、内周硬化層を形成すると共に、残存する前記外周硬
化層と内周硬化層との間の素地部は圧延素材の硬さであ
る第３工程、（ニ）焼戻しする第４工程、（ホ）仕上げ
加工する第５工程、以上の工程からなることを特徴とす
る。Further, in the method for manufacturing a crawler bushing according to the present invention, the fourth invention is (1) a first step of subjecting a rolled material to a bushing rough working material,
(B) Induction hardening is applied to the outer peripheral surface of the bushing rough processed material to form an outer peripheral hardened layer, and the inner peripheral surface side is the hardness of the rolled material in the second step. (C) The bushing rough processed material While cooling the outer peripheral surface, induction hardening is applied to the inner peripheral surface to form an inner peripheral hardened layer, and the base material between the remaining outer peripheral hardened layer and the inner peripheral hardened layer is the hardness of the rolled material. It is characterized by comprising a third step, (d) a fourth step of tempering, and (e) a fifth step of finishing.
【０００８】第５発明は、第４発明において、（ロ）
は、前記ブッシング粗加工材の内周面に高周波焼入れを
施し、内周硬化層を形成すると共に、外周面側は圧延素
材の硬さである第２工程、であり、（ハ）は、前記ブッ
シング粗加工材の内周面を冷却しつつ、外周面に高周波
焼入れを施し、外周硬化層を形成すると共に、残存する
前記内周硬化層と外周硬化層との間の素地部は圧延素材
の硬さである第３工程、である構成からなる。第６発明
は、第４発明又は第５発明において、圧延素材は焼なま
し素材あるいは焼ならし素材である。第７発明は、第４
発明乃至第６発明のいずれか１発明において、（ニ）焼
戻しする第４工程と、（ホ）仕上げ加工する第５工程と
の２工程において、少なくとも１工程を省略する。本発
明に係わる履帯用ブッシングおよびその製造方法は、以
上の構成とした。A fifth aspect of the invention is the same as the fourth aspect of the invention.
Is a second step in which the inner peripheral surface of the bushing rough processed material is subjected to induction hardening to form an inner peripheral hardened layer, and the outer peripheral surface side is the hardness of the rolled material, and (c) is the above While cooling the inner peripheral surface of the bushing rough-worked material, induction hardening is applied to the outer peripheral surface to form an outer peripheral hardened layer, and the base material between the remaining inner peripheral hardened layer and outer peripheral hardened layer is a rolled material. The third step, which is hardness, is configured. In a sixth aspect based on the fourth or fifth aspect, the rolled material is an annealed material or a normalized material. 7th invention, 4th
In any one of the invention to the sixth invention, at least one step is omitted in the two steps of (d) the fourth step of tempering and (e) the fifth step of finishing. The crawler belt bushing and the method for manufacturing the same according to the present invention are configured as described above.
【０００９】[0009]
【作用】上記構成による本発明の作用を図面を参照しつ
つ説明する。図１に本発明の履帯用ブッシングの断面を
示す。外周面１ａおよび内周面１ｂから肉厚心部１ｃに
向かってそれぞれ図示しない硬化層が形成される。該断
面のＡ−Ａ間で測定したブッシング１の断面硬さ分布を
模式的に図２に示す。図２において、内外周面側には、
それぞれ硬さＨＲＣ４５以上の内外周硬化層が形成さ
れ、外周硬化層厚さＬｏと内周硬化層厚さＬｉを要求さ
れる厚さにすることで、履帯用ブッシングの長期耐摩耗
性を得る。また、硬化層の主たる組織であるマルテンサ
イトは、高周波焼入れ時に膨張変態してできる組織であ
り、肉厚心部の素地部Ｌｍは未変態であるため、ブッシ
ングには図３に模式的に示す残留応力分布が生じる。内
周面および外周面には圧縮残留応力が生じており、ブッ
シングに加わる負荷に耐えるための疲労強度が向上す
る。The operation of the present invention having the above construction will be described with reference to the drawings. FIG. 1 shows a cross section of a track bushing of the present invention. Hardened layers (not shown) are formed from the outer peripheral surface 1a and the inner peripheral surface 1b toward the thick core portion 1c. The cross-sectional hardness distribution of the bushing 1 measured between AA of the cross section is schematically shown in FIG. In FIG. 2, on the inner and outer peripheral surface side,
The inner and outer peripheral hardened layers each having a hardness of HRC45 or higher are formed, and the outer peripheral hardened layer thickness Lo and the inner peripheral hardened layer thickness Li are set to required thicknesses to obtain long-term wear resistance of the track bushing. Further, martensite, which is the main structure of the hardened layer, is a structure formed by expansion transformation during induction hardening, and the base portion Lm of the thick core portion is not transformed, so that it is schematically shown in FIG. 3 for bushing. Residual stress distribution occurs. Compressive residual stress is generated on the inner peripheral surface and the outer peripheral surface, and the fatigue strength for withstanding the load applied to the bushing is improved.
【００１０】また、本発明において、圧延素材等を使用
することは、高周波焼入れ前の油焼入れと焼戻しとの工
程を省略あるいは簡略化するだけでなく、圧延素材など
の硬さが残存した素地部（Ｌｍ）の硬さが低いことでも
あり、このことがブッシングの内外周面の圧縮残留応力
を大きくする作用がある。また、素地部（Ｌｍ）を厚く
することは内外周面の圧縮残留応力を大きくする方向に
なるが、厚くなり過ぎると、長期使用時にこの圧縮残留
応力が減衰する。すなわち、内外周硬化層厚さの合計が
ブッシング肉厚に対して０．３５〜０．７にすること
で、長期使用でも内外周面の圧縮残留応力を維持でき
る。これらのことから、ブッシングの断面硬さ分布は略
Ｕ字形であることが必要である。Further, in the present invention, the use of a rolled material or the like not only omits or simplifies the steps of oil quenching and tempering before induction hardening, but also the base portion where the hardness of the rolled material remains. The hardness of (Lm) is also low, which has the effect of increasing the compressive residual stress on the inner and outer peripheral surfaces of the bushing. Further, thickening the base portion (Lm) tends to increase the compressive residual stress on the inner and outer peripheral surfaces, but if it is too thick, this compressive residual stress will be attenuated during long-term use. That is, when the total thickness of the inner and outer peripheral hardened layers is 0.35 to 0.7 with respect to the bushing thickness, the compressive residual stress of the inner and outer peripheral surfaces can be maintained even after long-term use. For these reasons, the cross-sectional hardness distribution of the bushing needs to be substantially U-shaped.
【００１１】さらに、高周波焼入れ前の油焼入れと焼戻
しとの工程を省略あるいは簡略化による、焼入れ歪みの
低減がある。これにより、仕上げ加工の工程を省略でき
る。また、ブッシングの断面硬さ分布は略Ｕ字形である
と共に素地部の硬さが低いので、ブッシングの靭性も向
上する。したがって、高周波焼入れ後の焼戻し工程を省
略できる。以上のことから、本発明は優れた作用に基づ
くことが明らかである。Furthermore, quenching distortion can be reduced by omitting or simplifying the steps of oil quenching and tempering before induction hardening. Thereby, the finishing process can be omitted. Further, since the cross-sectional hardness distribution of the bushing is substantially U-shaped and the hardness of the base portion is low, the toughness of the bushing is also improved. Therefore, the tempering process after induction hardening can be omitted. From the above, it is clear that the present invention is based on an excellent action.
【００１２】[0012]
【実施例】以下に、本発明に係わる履帯用ブッシングお
よびその製造方法の実施例につき、図面を参照して詳細
に説明する。本発明が適用される建設機械などの履帯の
概要を図４に示す。ブッシング１は、外周面が図示しな
い起動輪と噛合し、内周面がピン１２と摺動接触し、さ
らに両端がダストシ−ル１４と摺動接触する。ブッシン
グ１とピン１２とのそれぞれ１部がリンク１３ａ、１３
ｂに嵌合し、リンク１３ａ、１３ｂはボルト１６および
ナット１７によりシュ−１５に配設される。履帯１１は
多数のリンク１３ａ、１３ｂをピン１２で鎖状に連結し
て構成される。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a crawler belt bushing and a method of manufacturing the same according to the present invention will be described below in detail with reference to the drawings. FIG. 4 shows an outline of a crawler belt of a construction machine to which the present invention is applied. The bushing 1 has an outer peripheral surface that meshes with a starting wheel (not shown), an inner peripheral surface that is in sliding contact with the pin 12, and both ends that are in sliding contact with the dust seal 14. One part of each of the bushing 1 and the pin 12 is a link 13a, 13
The links 13a and 13b are fitted to the shoe b by means of bolts 16 and nuts 17. The crawler belt 11 is configured by connecting a large number of links 13a and 13b with a pin 12 in a chain shape.
【００１３】次に、本発明の製造方法により製造される
履帯用ブッシングについて、工程に基づき説明する。 （実施例１）本実施例で使用した中炭素低合金鋼の供試
材含有成分を表１に示す。Next, the track bushing manufactured by the manufacturing method of the present invention will be described based on steps. (Example 1) Table 1 shows the components contained in the test material of the medium carbon low alloy steel used in this example.
【００１４】[0014]
【表１】 [Table 1]
【００１５】第１工程において、前記中炭素低合金鋼を
筒状の圧延素材とし、機械加工等を施したブッシング粗
加工材（外径５９ｍｍ、内径３８ｍｍ、長さ１３８．５
ｍｍ）を用意する。この圧延素材の断面のビッカ−ス硬
さＨｖ（荷重は５ｋｇ。以下も同じ荷重で測定。）は２
３０〜２４０であり、ロックウェル硬さＨＲＣへの近似
的換算値は１８〜２２となる。なお、硬さ測定はビッカ
−ス硬さ計を使用したが、以下の説明ではロックウェル
硬さＨＲＣへの近似的換算値で述べる。機械加工後の硬
さ分布は圧延素材と同様である。In the first step, a bushing roughing material (outer diameter 59 mm, inner diameter 38 mm, length 138.5), which is obtained by machining the above-mentioned medium carbon low alloy steel into a cylindrical rolled material, and which has been machined, etc.
mm) is prepared. The Vickers hardness Hv of the cross section of this rolled material (the load is 5 kg. The same load is measured below) is 2
It is 30 to 240, and the approximate conversion value to Rockwell hardness HRC is 18 to 22. A Vickers hardness meter was used for hardness measurement, but in the following description, it will be described by an approximate conversion value to Rockwell hardness HRC. The hardness distribution after machining is similar to that of rolled material.
【００１６】次に、第２工程において、該ブッシング粗
加工材の軸線を中心にして回転させつつ移動させ、その
外周面を、周波数１０ｋＨｚ、出力１５０ｋｗの高周波
誘導電流により加熱し、所定加熱後ただちに５％ソリブ
ル溶液をスプレ−して焼入れを行う。この５％ソリブル
溶液は市販のもので良い。焼入れ後のブッシング粗加工
材の断面硬さ分布を図５に示す。外周面側に破線で示す
硬さＨＲＣ４５以上の硬化層が形成されており、肉厚心
部から内周面間の硬さは圧延素材の硬さと同様である。Next, in the second step, the bushing rough-worked material is rotated and moved about its axis, and its outer peripheral surface is heated by a high-frequency induction current having a frequency of 10 kHz and an output of 150 kw, and immediately after predetermined heating. A 5% soluble solution is sprayed and quenched. This 5% soluble solution may be commercially available. The cross-sectional hardness distribution of the bushing rough-worked material after quenching is shown in FIG. A hardened layer having a hardness of HRC45 or more shown by a broken line is formed on the outer peripheral surface side, and the hardness between the thick core portion and the inner peripheral surface is similar to that of the rolled material.
【００１７】続いて、第３工程において、前記焼入れ済
のブッシング粗加工材の軸線を中心にして回転させつつ
移動させ、その外周面を５％ソリブル溶液にて冷却する
と共に、該ブッシング粗加工材の内周面を周波数３０ｋ
Ｈｚ、出力１５０ｋｗの高周波誘導電流により加熱し、
所定加熱後ただちに５％ソリブル溶液をスプレ−して焼
入れを行う。ブッシング粗加工材の肉厚心部には圧延素
材の硬さである素地部があり、内外周面間の硬さ分布は
略Ｕ字形である。なお、硬さ分布は第５工程の仕上げ加
工後とほぼ同じであり省略する。Subsequently, in a third step, the bushing roughened material after quenching is moved while being rotated about the axis of the bushing roughened material, and the outer peripheral surface thereof is cooled with a 5% solible solution and the bushing roughened material is also moved. Frequency of 30k on the inner surface of
Heated by high frequency induction current of Hz, output 150kw,
Immediately after predetermined heating, a 5% solible solution is sprayed and quenched. The bushing rough-worked material has a base portion which is the hardness of the rolled material in the thick center portion, and the hardness distribution between the inner and outer peripheral surfaces is substantially U-shaped. Note that the hardness distribution is almost the same as that after the finishing process in the fifth step and is omitted.
【００１８】続いて、第４工程において、焼入れの完了
したブッシング粗加工材を電気炉にて１８０℃で焼戻し
を行う。なお、焼戻し温度は、焼入れされたブッシング
粗加工材の表面組織である焼入れマルテンサイトを焼戻
しマルテンサイト組織にする温度を選定すれば良く、１
８０℃に限定するものではない。また、この焼戻しは、
靭性が低く不安定な焼入れマルテンサイトを改善するた
めの熱処理であるから、衝撃など機械的負荷の小さい部
位に適用する場合はこの焼戻しを省略することが出来
る。また本発明は、素地部の硬さが低く、全体として靭
性が高いことからも、本工程は省略してよい。加熱は、
電気あるいはガス等での加熱、誘導加熱など通常の方法
で行えば良い。Then, in the fourth step, the bushing roughened material that has been hardened is tempered at 180 ° C. in an electric furnace. The tempering temperature may be selected such that the tempered martensite, which is the surface texture of the quenched bushing roughened material, becomes the tempered martensite texture.
It is not limited to 80 ° C. Also, this tempering
Since this is a heat treatment for improving quenching martensite which has low toughness and is unstable, this tempering can be omitted when it is applied to a site where mechanical load such as impact is small. Further, in the present invention, this step may be omitted because the hardness of the base portion is low and the toughness is high as a whole. Heating
It may be carried out by a usual method such as heating with electricity or gas or induction heating.
【００１９】そして、第５工程において、研磨加工によ
る仕上げ加工を行い、最終製品となる。本工程を終了し
た最終製品である本発明のブッシングの硬さ分布を図６
に示す。内外周面間の硬さ分布は略Ｕ字形であり、素地
部の硬さＨＲＣは１７〜２０、内周側と外周側との合計
硬化層厚さは、ブッシング肉厚に対し０．５９である。
なお、本実施例では仕上げ加工を行ったが、仕上げ加工
前のブッシング外径寸法のバラツキの幅は、下記比較例
で説明する従来法を１とすると、本発明は０．４５と大
幅に改善されており、本工程は省略してよい。Then, in the fifth step, finish processing by polishing is carried out to obtain a final product. FIG. 6 shows the hardness distribution of the bushing of the present invention, which is the final product after this step.
Shown in. The hardness distribution between the inner and outer peripheral surfaces is substantially U-shaped, the hardness HRC of the base portion is 17 to 20, and the total hardened layer thickness of the inner peripheral side and the outer peripheral side is 0.59 with respect to the bushing thickness. is there.
Although the finishing process was performed in the present embodiment, the width of the variation in the outer diameter of the bushing before the finishing process is significantly improved to 0.45 in the present invention when the conventional method described in the following comparative example is set to 1. However, this step may be omitted.
【００２０】（比較例）比較例として、従来法の一方法
を行う。第１工程において、実施例１と同じブッシング
粗加工材を用い、電気炉で８６０℃加熱後油焼入れを行
い、５７０℃で焼戻する。硬さＨＲＣは２８〜３１であ
る。第２工程の外周面高周波焼入れ、第３工程の内周面
高周波焼入れおよび第４工程の焼戻しはいづれも実施例
１と同じ条件で行った。そして、第５工程も実施例１と
同様に研磨加工を行い、最終製品とする。本工程後のブ
ッシングの硬さ分布を図１０に示す。内外周面間の硬さ
分布は略Ｕ字形であり、素地部の硬さＨＲＣは２８〜３
１、合計硬化層厚さはブッシング肉厚に対し０．５８で
ある。(Comparative Example) As a comparative example, a conventional method is performed. In the first step, the same bushing roughening material as in Example 1 was used, followed by heating in an electric furnace at 860 ° C., oil quenching, and tempering at 570 ° C. The hardness HRC is 28 to 31. The outer peripheral surface induction hardening of the second step, the inner peripheral surface induction hardening of the third step, and the tempering of the fourth step were performed under the same conditions as in Example 1. Then, in the fifth step as well, polishing is performed in the same manner as in Example 1 to obtain the final product. The hardness distribution of the bushing after this step is shown in FIG. The hardness distribution between the inner and outer peripheral surfaces is substantially U-shaped, and the hardness HRC of the base is 28 to 3
1. The total hardened layer thickness is 0.58 with respect to the bushing thickness.
【００２１】上述の本発明である実施例１と従来法であ
る比較例との履帯用ブッシングの品質に関し、詳細に説
明する。建設機械での品質を推定すべく、両例に基づく
履帯用ブッシングを製作し、テストベンチで疲労試験を
行った。図７にベンチ疲労試験結果を示す。図７（ａ）
において、縦軸のＷは建設機械の車両１台分重量の負荷
相当であり、印●は本発明品のデ−タ、印○は従来法品
でのデ−タである。また、図７（ｂ）は本試験で使用し
たベンチでの負荷方法の概要であり、治具２１に支持さ
れた履帯用ブッシング１にプッシュロッド２２を用い矢
印２３の方向に２Ｗの負荷を繰り返し加える。供試ブッ
シング本数は、本発明品でＮ＝９、従来法品でＮ＝３で
ある。試験の結果、破損までの平均回数は、本発明品が
８．５×１０5 回、従来法品が４．９×１０5 回であ
る。したがって、本発明品は従来法品と比較して、約
１．７倍もの疲労寿命を有していることが分かり、しか
も全ての本発明品が従来法品と同等以上である。これは
工程の違いに起因するものであり、図６と図１０とに示
すブッシングの断面硬さ分布に差異を生じる。この差異
は素地部の硬さに顕著に表れ、本発明品の硬さＨＲＣは
１７〜２０、従来法品のそれは２８〜３１である。つま
り、本発明品の肉厚心部の硬さが低いことが、内外周面
の圧縮残留応力を大きくして、疲労強度が高くなること
を示している。The quality of the crawler bushing of the above-described first embodiment of the present invention and the conventional comparative example will be described in detail. In order to estimate the quality of construction machinery, we made a track bushing based on both cases and conducted a fatigue test on a test bench. FIG. 7 shows the bench fatigue test result. Figure 7 (a)
In the figure, W on the vertical axis corresponds to the load of the weight of one vehicle of the construction machine, mark ● indicates the data of the present invention, and mark ○ indicates the data of the conventional method. Further, FIG. 7 (b) is an outline of the loading method on the bench used in this test, in which the push rod 22 is used for the track bushing 1 supported by the jig 21 and the load of 2 W is repeated in the direction of the arrow 23. Add. The number of test bushings is N = 9 for the product of the present invention and N = 3 for the conventional method product. As a result of the test, the average number of times until breakage is 8.5 × 10 5 times for the product of the present invention and 4.9 × 10 5 times for the conventional method product. Therefore, it can be seen that the products of the present invention have a fatigue life of about 1.7 times that of the products of the conventional method, and all the products of the present invention are equal to or more than the products of the conventional method. This is due to the difference in the process, and causes a difference in the cross-sectional hardness distribution of the bushing shown in FIGS. 6 and 10. This difference remarkably appears in the hardness of the base portion, the hardness HRC of the product of the present invention is 17 to 20, and that of the conventional product is 28 to 31. That is, it is shown that the low hardness of the thick core portion of the product of the present invention increases the compressive residual stress on the inner and outer peripheral surfaces and increases the fatigue strength.
【００２２】（実施例２）実施例１の一部を変更して行
った別の実施例について説明する。本実施例では、第１
工程において、圧延素材を焼なまし素材、焼ならし素材
等に変更し、素材硬さＨＲＣ１０〜３０程度の範囲に入
る、種々の水準の素材を使用する。第２工程において、
移動速度など高周波焼入れ条件を種々変更し、外周面側
の硬化層厚さを変化させる。第３工程において、高周波
焼入れ条件を種々変更し、本工程で内周側に形成される
内周硬化層厚さと第２工程で形成される外周硬化層厚さ
との合計した硬化層厚さが、ブッシング粗加工材の肉厚
に対して、０．３５〜０．７であり、かつブッシング粗
加工材の肉厚心部には焼なまし素材、焼ならし素材等の
硬さである素地部があり、内外周面間の硬さ分布は略Ｕ
字形に調整する。以上の工程以外は実施例１と同様に行
った。なお、実施例２を行う際、内周硬化層厚さと外周
硬化層厚さとの合計した硬化層厚さが、ブッシング粗加
工材の肉厚に対して、０．３５〜０．７以外のブッシン
グも製作した。(Embodiment 2) Another embodiment in which a part of Embodiment 1 is modified will be described. In this embodiment, the first
In the process, the rolled material is changed to an annealed material, a normalized material, etc., and various levels of material having a material hardness HRC of about 10 to 30 are used. In the second step,
The induction hardening conditions such as moving speed are variously changed to change the thickness of the hardened layer on the outer peripheral surface side. In the third step, various induction hardening conditions are changed, and the total hardened layer thickness of the inner hardened layer thickness formed on the inner circumferential side in this step and the outer hardened layer thickness formed in the second step is A base part that is 0.35 to 0.7 with respect to the wall thickness of the bushing rough processed material, and has a hardness of an annealed material, a normalized material, etc. at the thick center of the bushing rough processed material. And the hardness distribution between the inner and outer peripheral surfaces is approximately U
Adjust to a glyph. Except for the above steps, the same procedure as in Example 1 was performed. In addition, when Example 2 is performed, the total hardened layer thickness of the inner peripheral hardened layer thickness and the outer peripheral hardened layer thickness is a bushing other than 0.35 to 0.7 with respect to the wall thickness of the bushing rough processed material. Also made.
【００２３】以上の実施例２の機械的特性に関し、図面
を参照しつつ詳述する。なお、本発明について分かりや
すくするため、合計した硬化層厚さがブッシング粗加工
材の肉厚に対して０．３５〜０．７以外に関しても、含
めて説明する。既述のブッシング断面硬さ分布図２にお
いて、ブッシング肉厚Ｌに対する、外周硬化層厚さＬｏ
と内周硬化層厚さＬｉとを加えた合計硬化層厚さの比を
硬化層比（（Ｌｏ＋Ｌｉ）／Ｌ）とする。実施例２で得
られたブッシングについて、硬化層比をパラメ−タとす
る時の、内周面の円周方向残留応力を図８に示す。この
残留応力はＸ線法により測定した。素地硬さＨＲＣ１０
および３０について図示してあるが、素地硬さが１０お
よび３０の範囲内にある場合は、図示の２曲線の間にあ
る。前述のように、疲労強度を確保するためには圧縮残
留応力が生じている方が有効であり、硬化層比が約０．
７以下では内周面の円周方向残留応力は圧縮残留応力と
なる。また、イ）素地部の硬さの低い方が圧縮残留応力
は大きくなり、ロ）硬化層比が大きすぎると残留応力は
引張残留応力に転じる、ことも明らかになった。The mechanical characteristics of the second embodiment will be described in detail with reference to the drawings. In addition, in order to make it easy to understand the present invention, description will be made including a case where the total thickness of the hardened layer is other than 0.35 to 0.7 with respect to the wall thickness of the bushing rough processed material. In the above-described bushing cross-section hardness distribution diagram 2, the outer peripheral hardened layer thickness Lo with respect to the bushing thickness L
The ratio of the total hardened layer thickness obtained by adding the inner hardened layer thickness Li to the hardened layer ratio ((Lo + Li) / L). FIG. 8 shows the residual stress in the circumferential direction of the inner peripheral surface of the bushing obtained in Example 2 when the ratio of the hardened layer is used as the parameter. This residual stress was measured by the X-ray method. Base hardness HRC10
And 30 are shown, but when the green hardness is in the range of 10 and 30, it lies between the two curves shown. As described above, in order to secure the fatigue strength, it is more effective that the compressive residual stress is generated, and the hardened layer ratio is about 0.
When it is 7 or less, the circumferential residual stress on the inner peripheral surface becomes a compressive residual stress. It was also clarified that (a) the lower the hardness of the base material, the greater the compressive residual stress, and (b) if the ratio of the hardened layer is too large, the residual stress turns into a tensile residual stress.
【００２４】また、実施例２で得られたブッシングにつ
いて、硬化層比をパラメ−タとする時の、残留応力減衰
率を図９に示す。この残留応力減衰率は、建設機械など
での長期使用における、ブッシング内外周面の圧縮残留
応力の低下、すなわち疲労強度の低下を推定できる。図
９において、残留応力減衰率は、（初期のブッシング内
周面の円周方向残留応力σ0 −繰り返し負荷後のブッシ
ング内周面の円周方向残留応力）／σ0 、より求めた。
繰り返し負荷条件は、ブッシング内周面の応力が１１７
６Ｎ／ｍｍ2 となる負荷で１００００回の繰り返しであ
る。図中には素地硬さＨＲＣ１０および３０について示
してあるが、素地硬さが１０および３０の範囲内にある
場合は、図示の２曲線の間にある。この図より、硬化層
比が小さい場合、ブッシングに高負荷がかかると、素地
部が降伏し、硬化層に生じている圧縮残留応力が開放さ
れ、減衰することが推察され、ハ）素地部の硬さが低い
ほど減衰しやすい、ニ）硬化層比が低いほど減衰しやす
い、ホ）硬化層比をある程度以上大きくすれば素地部の
硬さに関係なく減衰しない、等が明らかになる。したが
って、長期使用における疲労強度が確保されるために
は、残留応力減衰率が小さいか好ましくは０であること
が必要であり、本実施例の硬化層比０．３５以上であれ
ば残留応力減衰率０を満足する。FIG. 9 shows the residual stress attenuation rate of the bushing obtained in Example 2 when the ratio of the hardened layer is used as a parameter. This residual stress decay rate can be estimated as a decrease in compressive residual stress on the inner and outer peripheral surfaces of the bushing, that is, a decrease in fatigue strength, during long-term use in construction machinery and the like. In FIG. 9, the residual stress attenuation rate was calculated from (initial circumferential residual stress of the bushing inner peripheral surface σ 0 −circumferential residual stress of the bushing inner peripheral surface after repeated loading) / σ 0 .
Under repeated loading conditions, the stress on the inner surface of the bushing is 117
It is repeated 10,000 times under a load of 6 N / mm 2 . Although the base hardnesses HRC10 and 30 are shown in the figure, when the base hardness is in the range of 10 and 30, it is between the two curves shown. From this figure, it can be inferred that when the bushing is subjected to a high load when the hardened layer ratio is small, the base part yields, and the compressive residual stress generated in the hardened layer is released and attenuated. It becomes clear that the lower the hardness, the easier the damping, the lower the hardened layer ratio, the easier the damping, and the higher the hardened layer ratio, the more the damping ratio does not decrease regardless of the hardness of the base. Therefore, in order to secure the fatigue strength in long-term use, it is necessary that the residual stress attenuation rate is small or preferably 0. If the hardened layer ratio of this example is 0.35 or more, the residual stress attenuation is required. Satisfies the rate 0.
【００２５】したがって、前述の実施例２に関する円周
方向残留応力および残留応力減衰率から、硬化層比は
０．３５〜０．７が好ましいことが分かる。なお、該硬
化層比の範囲は、高周波焼入れ前の種々の素材の硬さを
包括する場合であり、素地硬さが低い場合、たとえば素
地硬さＨＲＣ１０で圧縮残留応力を得る為には硬化層比
０．８以下であればよい。Therefore, it can be seen from the circumferential residual stress and the residual stress attenuation rate relating to Example 2 that the hardened layer ratio is preferably 0.35 to 0.7. The range of the hardened layer ratio is the case of including the hardness of various materials before induction hardening, and when the base material hardness is low, for example, to obtain a compressive residual stress with the base material hardness HRC10, the hardened layer ratio is set. The ratio may be 0.8 or less.
【００２６】以上、実施例１および２について詳述した
が、履帯用ブッシングにおいて、圧延素材、焼なまし素
材、焼ならし素材あるいは硬さＨＲＣ１０〜３０程度の
素材を使用し、内外周面に高周波焼入れを施し、必要に
応じて焼戻しを行い、肉厚心部に素材硬さを残存した素
地部を有する略Ｕ字形の硬さ分布とすればよい。また、
硬化層比は好ましくは０．３５〜０．７にすると良い。Examples 1 and 2 have been described in detail above. In a track bushing, a rolling material, an annealing material, a normalizing material, or a material having a hardness of HRC10 to 30 is used and the inner and outer peripheral surfaces are formed. Induction hardening may be performed, and tempering may be performed as necessary to obtain a substantially U-shaped hardness distribution having a base portion in which the material hardness remains in the thick core portion. Also,
The hardening layer ratio is preferably 0.35 to 0.7.
【００２７】なお、材料は中炭素低合金鋼について開示
したが、限定するものではなく、他の鋼でも良い。ま
た、高周波焼入れ工程で、外周面焼入れを先に施した
が、内周面焼入れを先に施しても同様の成果が得られ
る。Although the medium carbon low alloy steel has been disclosed as the material, the material is not limited and other steel may be used. Further, in the induction hardening process, the outer peripheral surface is quenched first, but the same result can be obtained by performing the inner peripheral surface quenching first.
【００２８】[0028]
【発明の効果】本発明は、以上説明したように構成され
ているので、以下に記載されるような効果を奏する。高
周波焼入れ前の素材として、圧延、焼なましあるいは焼
ならし等の素材が使用できるので、油焼入れ・焼戻しに
よる調質工程が省略あるいは簡略化され、工程の管理が
容易になり、かつコストが改善されると共に、油焼入れ
での歪みが小さくなり、仕上げ加工の省略も可能であ
る。また、内外周側に硬化層を有し、肉厚心部に硬さの
低い素材硬さを残存した素地部を有する略Ｕ字形の硬さ
分布とすることで、内外周面の圧縮残留応力を大きくす
ることが容易となり、従来のブッシングと同程度以上の
疲労強度を持つ高品質の履帯用ブッシングが得られる。
前述した、硬さの低い素地部と略Ｕ字形の硬さ分布から
ブッシングの靭性が高く、高周波焼入れ後の焼戻し工程
の省略が可能である。さらに、ブッシング肉厚に対す
る、外周硬化層厚さと内周硬化層厚さとを加えた合計硬
化層厚さの比である硬化層比は、０．３５〜０．７と広
範囲で高品質の履帯用ブッシングが得られるので、厚肉
なブッシングの場合、硬化層が比較的浅くてよく、高周
波焼入れに要するエネルギ−コストの上昇を抑制できる
と共に、熱処理条件も幅広く選定できるため、１台の高
周波焼入れ装置が効率よく活用できる。Since the present invention is constructed as described above, it has the following effects. Since materials such as rolling, annealing or normalizing can be used as the material before induction hardening, the tempering process by oil quenching / tempering can be omitted or simplified, the process management becomes easy and the cost is low. In addition to being improved, the distortion in oil quenching is reduced, and the finishing process can be omitted. Also, by having a hardened layer on the inner and outer peripheral sides and a substantially U-shaped hardness distribution that has a base material with a low hardness remaining in the thick core, the compressive residual stress on the inner and outer peripheral surfaces It is easy to increase the size of the shoe, and a high-quality track bushing having a fatigue strength equal to or higher than that of a conventional bushing can be obtained.
Since the bushing has high toughness due to the aforementioned low hardness base portion and the substantially U-shaped hardness distribution, the tempering process after induction hardening can be omitted. Further, the hardened layer ratio, which is the ratio of the total hardened layer thickness obtained by adding the outer hardened layer thickness and the inner hardened layer thickness to the bushing thickness, is 0.35 to 0.7, which is a wide range and for high quality crawler tracks. Since a bushing can be obtained, in the case of a thick bushing, the hardened layer may be relatively shallow, the increase in energy cost required for induction hardening can be suppressed, and a wide range of heat treatment conditions can be selected. Can be used efficiently.
【図１】本発明に係わる履帯用ブッシングの断面図であ
る。FIG. 1 is a cross-sectional view of a track bushing according to the present invention.
【図２】本発明に係わるブッシングの断面硬さ分布の模
式図である。FIG. 2 is a schematic diagram of a cross-sectional hardness distribution of the bushing according to the present invention.
【図３】本発明に係わるブッシングの残留応力分布の模
式図である。FIG. 3 is a schematic diagram of residual stress distribution of a bushing according to the present invention.
【図４】本発明に係わる建設機械などの履帯の概要図で
ある。FIG. 4 is a schematic view of a crawler belt of a construction machine or the like according to the present invention.
【図５】実施例１に係わる外周面焼入れ後のブッシング
粗加工材の断面硬さ分布図である。5 is a cross-sectional hardness distribution diagram of the bushing rough-worked material after quenching the outer peripheral surface according to Example 1. FIG.
【図６】実施例１に係わる最終製品でのブッシングの硬
さ分布図である。6 is a hardness distribution diagram of bushings in the final product according to Example 1. FIG.
【図７】実施例１に係わるベンチ疲労試験結果を示す図
である。FIG. 7 is a diagram showing bench fatigue test results according to Example 1.
【図８】実施例２に係わる内周面の円周方向残留応力を
示す図である。FIG. 8 is a diagram showing the residual stress in the circumferential direction of the inner peripheral surface according to the second embodiment.
【図９】実施例２に係わる残留応力減衰率を示す図であ
る。9 is a diagram showing a residual stress attenuation rate according to Example 2. FIG.
【図１０】従来の最終製品でのブッシングの硬さ分布図
である。FIG. 10 is a hardness distribution diagram of a bushing in a conventional final product.
１ ブッシング １ａ 外周面 １ｂ 内周面 １ｃ 肉厚心部 １１ 履帯 Ｌ ブッシング肉厚 Ｌｏ 外周硬化層厚さ Ｌｉ 内周硬化層厚さ Ｌｍ 素地部 1 Bushing 1a Outer peripheral surface 1b Inner peripheral surface 1c Thick-walled core part 11 Crawler track L Bushing wall-thickness Lo Outer peripheral hardened layer thickness Li Inner hardened layer thickness Lm Base part
Claims (7)
び内周面（１ｂ）から肉厚心部（１ｃ）に向かって、そ
れぞれ高周波焼入れによる硬化層が形成されていると共
に、両硬化層の間の肉厚心部（１ｃ）には、高周波焼入
れ前の圧延素材の硬さが残存した素地部（Ｌｍ）を有し
ており、内外周面間の硬さ分布が略Ｕ字形であることを
特徴とする履帯用ブッシング。1. A hardened layer is formed by induction hardening from an outer peripheral surface (1a) and an inner peripheral surface (1b) of a bushing (1) toward a thick core portion (1c), and both hardened layers are formed. The thick core portion (1c) between the two has a base portion (Lm) where the hardness of the rolled material before induction hardening remains, and the hardness distribution between the inner and outer peripheral surfaces is substantially U-shaped. Crawler bushing characterized by
周波焼入れ前の焼なまし素材あるいは焼ならし素材の硬
さである請求項１に記載の履帯用ブッシング。2. The track bushing according to claim 1, wherein the hardness of the rolled material before induction hardening is the hardness of the annealed material or the normalized material before induction hardening.
らの外周硬化層厚さ（Ｌｏ）と内周面（１ｂ）からの内
周硬化層厚さ（Ｌｉ）とを加えた硬化層厚さは、ブッシ
ング肉厚（Ｌ）に対して０．３５〜０．７である請求項
１又は請求項２記載の履帯用ブッシング。3. The hardening layer thickness obtained by adding the outer circumference hardening layer thickness (Lo) from the outer circumference surface (1a) and the inner circumference hardening layer thickness (Li) from the inner circumference surface (1b) in induction hardening is The bushing for a crawler belt according to claim 1 or 2, having a bushing thickness (L) of 0.35 to 0.7.
する機械加工を施す第１工程、（ロ）前記ブッシング粗
加工材の外周面に高周波焼入れを施し、外周硬化層を形
成すると共に、内周面側は圧延素材の硬さである第２工
程、（ハ）前記ブッシング粗加工材の外周面を冷却しつ
つ、内周面に高周波焼入れを施し、内周硬化層を形成す
ると共に、残存する前記外周硬化層と内周硬化層との間
の素地部は圧延素材の硬さである第３工程、（ニ）焼戻
しする第４工程、（ホ）仕上げ加工する第５工程、以上
の工程からなることを特徴とする履帯用ブッシング製造
方法。4. (a) A first step of machining a rolled material into a bushing rough-worked material, (b) induction hardening is applied to the outer peripheral surface of the bushing rough-worked material to form an outer hardened layer, and The second step is the hardness of the rolled material on the inner peripheral surface side. (C) While cooling the outer peripheral surface of the bushing rough processed material, induction hardening is applied to the inner peripheral surface to form an inner peripheral hardened layer, The remaining base material between the outer peripheral hardened layer and the inner peripheral hardened layer is the hardness of the rolled material, ie, the third step, (d) the fourth step of tempering, and (e) the fifth step of finishing. A method for manufacturing a track bushing, comprising the steps of:
周面に高周波焼入れを施し、内周硬化層を形成すると共
に、外周面側は圧延素材の硬さである第２工程、であ
り、（ハ）は、前記ブッシング粗加工材の内周面を冷却
しつつ、外周面に高周波焼入れを施し、外周硬化層を形
成すると共に、残存する前記内周硬化層と外周硬化層と
の間の素地部は圧延素材の硬さである第３工程、である
構成からなる請求項４記載の履帯用ブッシング製造方
法。5. In the second step, (b) is a second step in which the inner peripheral surface of the bushing rough-worked material is subjected to induction hardening to form an inner peripheral hardened layer, and the outer peripheral surface side is the hardness of the rolled material. There is (c), while cooling the inner peripheral surface of the bushing rough processed material, induction hardening is applied to the outer peripheral surface to form an outer peripheral hardened layer, and the remaining inner peripheral hardened layer and outer peripheral hardened layer The bushing manufacturing method for a crawler track according to claim 4, wherein the base material portion between is the third step which is the hardness of the rolled material.
し素材である請求項４又は５記載の履帯用ブッシング製
造方法。6. The method of manufacturing a track bushing according to claim 4, wherein the rolled material is an annealed material or a normalized material.
上げ加工する第５工程との２工程において、少なくとも
１工程を省略する請求項４〜６のいずれか１項に記載の
履帯用ブッシング製造方法。7. The crawler belt according to claim 4, wherein at least one step is omitted in the two steps of (d) the fourth step of tempering and (e) the fifth step of finishing. Bushing manufacturing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14253993A JP3351860B2 (en) | 1993-05-24 | 1993-05-24 | Crawler track bushing and method of manufacturing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14253993A JP3351860B2 (en) | 1993-05-24 | 1993-05-24 | Crawler track bushing and method of manufacturing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06329056A true JPH06329056A (en) | 1994-11-29 |
| JP3351860B2 JP3351860B2 (en) | 2002-12-03 |
Family
ID=15317711
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14253993A Expired - Fee Related JP3351860B2 (en) | 1993-05-24 | 1993-05-24 | Crawler track bushing and method of manufacturing the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3351860B2 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6270595B1 (en) | 1997-08-25 | 2001-08-07 | Komatsu Ltd. | Bushing for crawler belt and method of manufacture |
| JP2002114177A (en) * | 2000-08-31 | 2002-04-16 | Caterpillar Inc | Bush hardening method of caterpillar band chain |
| KR100619226B1 (en) * | 2005-02-01 | 2006-08-31 | 권병호 | Manufacturing method of track link bushing for heavy equipment |
| JP2007269224A (en) * | 2006-03-31 | 2007-10-18 | Komatsu Ltd | Crawler sleeve processing method |
| KR20160039329A (en) * | 2014-10-01 | 2016-04-11 | 두산인프라코어 주식회사 | Track bush for crawler track |
| JP2022548393A (en) * | 2019-09-26 | 2022-11-18 | キャタピラー インコーポレイテッド | high carbon steel track bushing |
-
1993
- 1993-05-24 JP JP14253993A patent/JP3351860B2/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6270595B1 (en) | 1997-08-25 | 2001-08-07 | Komatsu Ltd. | Bushing for crawler belt and method of manufacture |
| JP2002114177A (en) * | 2000-08-31 | 2002-04-16 | Caterpillar Inc | Bush hardening method of caterpillar band chain |
| KR100619226B1 (en) * | 2005-02-01 | 2006-08-31 | 권병호 | Manufacturing method of track link bushing for heavy equipment |
| JP2007269224A (en) * | 2006-03-31 | 2007-10-18 | Komatsu Ltd | Crawler sleeve processing method |
| KR20160039329A (en) * | 2014-10-01 | 2016-04-11 | 두산인프라코어 주식회사 | Track bush for crawler track |
| JP2022548393A (en) * | 2019-09-26 | 2022-11-18 | キャタピラー インコーポレイテッド | high carbon steel track bushing |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3351860B2 (en) | 2002-12-03 |
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