JPS6221071B2 - - Google Patents
Info
- Publication number
- JPS6221071B2 JPS6221071B2 JP13435482A JP13435482A JPS6221071B2 JP S6221071 B2 JPS6221071 B2 JP S6221071B2 JP 13435482 A JP13435482 A JP 13435482A JP 13435482 A JP13435482 A JP 13435482A JP S6221071 B2 JPS6221071 B2 JP S6221071B2
- Authority
- JP
- Japan
- Prior art keywords
- shift fork
- layer
- cast iron
- sliding surface
- hardened
- 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
Links
- 239000010410 layer Substances 0.000 claims description 27
- 229910001018 Cast iron Inorganic materials 0.000 claims description 13
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 claims description 13
- 230000008878 coupling Effects 0.000 claims description 12
- 238000010168 coupling process Methods 0.000 claims description 12
- 238000005859 coupling reaction Methods 0.000 claims description 12
- 229910001567 cementite Inorganic materials 0.000 claims description 10
- 150000004767 nitrides Chemical class 0.000 claims description 5
- 239000002344 surface layer Substances 0.000 claims description 5
- 238000010894 electron beam technology Methods 0.000 claims description 3
- 239000000463 material Substances 0.000 description 13
- 210000000078 claw Anatomy 0.000 description 8
- 238000007747 plating Methods 0.000 description 7
- 238000000576 coating method Methods 0.000 description 6
- 238000005121 nitriding Methods 0.000 description 6
- 239000011248 coating agent Substances 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 4
- 229910001141 Ductile iron Inorganic materials 0.000 description 4
- 230000006698 induction Effects 0.000 description 4
- 239000003921 oil Substances 0.000 description 4
- 239000011347 resin Substances 0.000 description 4
- 229920005989 resin Polymers 0.000 description 4
- 238000005266 casting Methods 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 102220259718 rs34120878 Human genes 0.000 description 2
- 238000007751 thermal spraying Methods 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 229910017060 Fe Cr Inorganic materials 0.000 description 1
- 229910002544 Fe-Cr Inorganic materials 0.000 description 1
- 229910017116 Fe—Mo Inorganic materials 0.000 description 1
- 229910001296 Malleable iron Inorganic materials 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 229910000746 Structural steel Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000005256 carbonitriding Methods 0.000 description 1
- 238000005255 carburizing Methods 0.000 description 1
- UPHIPHFJVNKLMR-UHFFFAOYSA-N chromium iron Chemical compound [Cr].[Fe] UPHIPHFJVNKLMR-UHFFFAOYSA-N 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 239000012208 gear oil Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910001337 iron nitride Inorganic materials 0.000 description 1
- 238000005461 lubrication Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 229910000734 martensite Inorganic materials 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 102200082816 rs34868397 Human genes 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/02—Pretreatment of the material to be coated
-
- 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
- F16H—GEARING
- F16H63/00—Control outputs from the control unit to change-speed- or reversing-gearings for conveying rotary motion or to other devices than the final output mechanism
- F16H63/02—Final output mechanisms therefor; Actuating means for the final output mechanisms
- F16H63/30—Constructional features of the final output mechanisms
- F16H63/32—Gear shift yokes, e.g. shift forks
- F16H2063/324—Gear shift yokes, e.g. shift forks characterised by slide shoes, or similar means to transfer shift force to sleeve
Description
本発明は鋳鉄製のギヤシフトフオークに関し、
特にギヤカツプリングスリーブと摺動するシフト
フオーク先端爪部の摺動面部分の耐摩耗特性を著
しく向上せしめたシフトフオークに関するもので
ある。
従来から、車両のトランスミツシヨン部品であ
るギヤシフトフオークでは、球状黒鉛鋳鉄、可鍛
鋳鉄或いはS45C、S55Cの如き機械構造用鋼を用
いて鋳造、熱間鋳造等により、その粗形材を製作
した後、機械加工によりシフトフオークの所要形
状に形成せしめ、更にその爪部分、換言すればギ
ヤカツプリングスリーブとの摺動面部分に高周波
焼入れ、クロムメツキ処理、浸炭窒化処理、溶射
或いは樹脂コート等が施されて、耐摩耗性を持た
せた製品とされている。
しかしながら、高周波焼入れを行なつたシフト
フオークでは、焼入れにより形成されたマルテン
サイトが、相手摺動材との微視的金属接触によつ
て惹起される接触面における温度上昇により分解
し、このため硬度が低下して、前記ギヤカツプリ
ングスリーブとの摺動面の摩耗が進行するなどの
問題がある。また、従来のクロム等の耐摩耗特性
のあるメツキ層を接触面に形成する場合も、素地
の硬さがHv250〜290程度のものにメツキした場
合には、摺動面の接触面圧が50Kg／cm2程度を超え
るようになると素地とメツキ層との間の境界面に
剥離が生じ、このため繰り返し接触荷重が加わる
とメツキ層にクラツクが発生する問題を生じ、そ
してこの状態が進行することにより、メツキ層の
素地からの剥離が起こり、耐摩耗性が著しく低下
することになる。
一方、溶射等によつて、前記摺動面をFe−Mo
合金、Fe−Cr合金等にてコートする方法はコス
ト的に高いものになつてしまい、好ましくなく、
また樹脂をコートする方法は、コートする材料と
して油となじみ性の良好な材料を選択すれば、シ
フトフオークとそれに嵌合されているスリーブと
の間の油潤滑性は良くなり、耐摩耗特性は向上す
るものの、そのような樹脂のコートの場合にあつ
ては、シフトフオーク爪部の摺動面のフオークシ
ヤフト穴に対する直角度が十分に良好に確保され
ていないと、局部片当たりによつてコートした樹
脂が容易に溶損してしまい、その耐久性に欠ける
問題がある。
さらに、球状黒鉛鋳鉄にガス軟窒化処理、タフ
トライド処理等を施し、爪部摺動面に鉄窒化物層
を形成させたシフトフオークは、浸炭処理等が施
された鋼製スリーブに対して、耐摩耗性、なじみ
性とも良好な特性を示すが、高負荷を受けるシフ
トフオークにあつては、かかる窒化物層が爪部摺
動面に５μ前後しか形成され得ないために、この
窒化物層が摩耗してしまうと、急激に摩耗が進行
してしまう等の問題を内在している。
ここにおいて、本発明はかかる事情に鑑みて為
されたものであつて、その目的とするところは、
鋳鉄製のギヤシフトフオークにおいて、それのギ
ヤカツプリングスリーブとの摺動面の耐摩耗特性
を著しく高めることにあり、またそのような高耐
摩耗特性のシフトフオークを比較的低コストで製
造可能と為すことにある。
本発明は、かかる目的を達成するために、少な
くともギヤカツプリングスリーブと摺動する鋳鉄
製シフトフオーク先端爪部の摺動面を、レーザ、
TIGアーク、電子ビーム等の高エネルギー密度源
により再溶融して、該摺動面の表層物にセメンタ
イト硬化層を形成せしめた後、更に窒化処理を施
して窒化物層を形成せしめるようにしたことにあ
り、これによつて、低粘度オイルを使用する等、
潤滑条件が悪く、またそれ自体にもかなりの高負
荷がかかるために高耐摩耗特性が要求されるシフ
トフオークに対し、その耐摩耗特性を著しく高
め、しかも比較的低コストで製造し得るようにし
たのである。
以下、本発明に係るシフトフオークとその製造
法の一実施例を示す図面を参照しつつ、更に詳細
に説明することとする。
第１図において、１は鋳鉄製のシフトフオーク
であつて、その半円形乃至は馬蹄形を為す爪部先
端部分２及び３が所定のギヤカツプリングスリー
ブに対する摺動部とされている。なお、４，５は
図面に対して垂直な方向に延びるフオークシヤフ
ト穴である。ところで、かかるシフトフオーク１
を構成する材質は鋳鉄であるが、一般に球状黒鉛
鋳鉄（FCD）が用いられるものであり、そして
そのような球状黒鉛鋳鉄は通常Ｃ：3.2〜4.0％、
Mn：0.2〜0.7％、Ｐ：0.01〜0.04％、Ｓ：0.01〜
0.03％、Si：1.6〜2.9％、Fe：残部からなるもの
であつて、それらの範囲内から各成分の含有量が
適宜に決定されることとなるのである。
そして、そのような鋳鉄組成を与える各成分を
含む溶湯は、常法に従つて、シフトフオーク用鋳
型に鋳込まれ、これによつて鋳造粗材が製造され
ることとなる。次いで、この得られたシフトフオ
ーク粗形材に対して熱処理、例えば930℃の温度
で１時間保持した後、空冷する処理が施され、そ
の鋳造時に受けた歪みなどを除去した後、切削加
工して第１図に示す形状のギヤシフトフオーク素
材が形成されるのである。
本発明では、このようにして得られたギヤシフ
トフオーク素材に対して、その少なくともギヤカ
ツプリングスリーブと摺動する先端爪部の摺動面
２，３にレーザ（光線）、TIG（タングステン・
イナート・ガス）アーク、電子ビーム等の高エネ
ルギー密度源を作用せしめ、その最表層のみを再
溶融せしめることによつて、その溶融部分にセメ
ンタイト組織を晶出させて硬化せしめ、以て該摺
動面の表層部にセメンタイト硬化層が形成せしめ
られるようにしたのである。なお、かかるシフト
フオーク素材の摺動面２，３上には、上記の如き
高エネルギー密度源が作用せしめられると共に、
一般にそのような高エネルギー密度源はスポツト
として所定の速度で該摺動面上を操作させられる
こととなる。そして、かかる高エネルギー密度源
のスポツトが当てられると、その付近の鋳鉄組織
の表層部が溶融させられるのであるが、そのスポ
ツトの形状やその走査速度、また走査線の間隔等
は再溶融操作が施されるべき少なくともシフトフ
オークの摺動面に所定の溶融層がほぼ一様に形成
されるように決定されるものである。また、この
ような再溶融操作によつて溶融せしめられて所望
のセメンタイト組織が晶出される表層部の厚さは
目的に応じて適宜に決定され、例えば２、３mm程
度或はそれ以上に達する場合もあるが、一般には
0.5〜１mm程度の厚さ（深さ）において再溶融さ
れ、所望の硬化層が形成されることとなる。
次いで、このようにして形成されたセメンタイ
ト硬化層を少なくともその摺動面２，３に有する
ギヤシフトフオーク素材には、前記再溶融操作に
よつて摺動面に発生した若干の歪みを取り除くた
めに0.2〜0.3mm程度の研摩加工が施された後、本
発明に従つて所定の窒化処理が施され、これによ
つて前記再溶融せしめられた摺動面部分、換言す
ればセメンタイト硬化層に更に窒化物層が形成さ
れるのである。なお、かかる窒化処理はギヤシフ
トフオーク１全体に施す必要はなく、場合によつ
ては、特に摩耗の激しい部分であるギヤシフトフ
オーク１のスリーブ摺動面２，３に施すだけでも
何等差し支えない。また、窒化処理としては、公
知の各種の手法を採用することができ、例えばア
ンモニアガスを含む雰囲気下において500〜600℃
程度の温度で所定時間保持するガス軟窒化処理
や、塩浴を用いるタフトライド処理等が採用され
るのである。
かくして得られたギヤシフトフオークは、その
少なくともギヤカツプリングスリーブと摺動する
先端爪部の摺動面が再溶融によつて形成されたセ
メンタイト硬化層と更にその上に形成された窒化
物層によつて覆われており、それ故その耐摩耗特
性が格段に向上せしめられているのであり、また
その耐久性も優れているのである。また、かかる
本発明によれば、簡単な装置によりシフトフオー
ク摺動部表面を最小限に再溶融、硬化させること
で、初期なじみ性と耐摩耗性を著しく向上せしめ
た、良好なギヤシフトフオークを与えることとな
つたのである。
因みに、このようにして製作された本発明に従
うシフトフオークと従来のものとの耐摩耗性の比
較が第２図に示されている。図中、ＡはS55C製
品を高周波焼入れしたもの、Ｂは鋳鉄製品を高周
波焼入れしたもの、Ｃは鋳鉄製品にクロムメツキ
を施したもの、Ｄは鋳鉄製品をガス軟窒化処理し
たもの（以上、４製品が従来品乃至比較品）、そ
してＥが本発明品であり、これらをそれぞれトラ
ンスミツシヨンに組み付けて行なつた総摩擦仕事
量に対する摩耗量（摩耗した厚さ）の試験結果
が、第２図にそれぞれ図示されている。なお、本
発明品Ｅは、黒鉛球状鋳鉄からなるギヤシフトフ
オーク素材をTIG溶接機によるアークで、その摺
動面２，３に対して、下表に示すような条件下：
The present invention relates to a cast iron gear shift fork,
In particular, the present invention relates to a shift fork that has significantly improved wear resistance on the sliding surface of the tip claw of the shift fork that slides on the gear coupling sleeve. Traditionally, gear shift forks, which are transmission parts for vehicles, have been made into rough shapes by casting, hot casting, etc. using spheroidal graphite cast iron, malleable cast iron, or machine structural steel such as S45C and S55C. After that, the shift fork is formed into the desired shape by machining, and the claw part, in other words, the sliding surface part with the gear coupling sleeve, is subjected to induction hardening, chrome plating, carbonitriding, thermal spraying, resin coating, etc. It is said to be a wear-resistant product. However, in shift forks subjected to induction hardening, the martensite formed by hardening decomposes due to the temperature rise at the contact surface caused by microscopic metal contact with the mating sliding material, resulting in hardness. There is a problem in that the friction of the gear coupling sleeve decreases and the sliding surface with the gear coupling sleeve progresses in wear. In addition, even when forming a plating layer with wear-resistant properties such as conventional chrome on the contact surface, if the plating layer has a hardness of about 250 to 290 Hv, the contact pressure on the sliding surface will be 50 kg. / cm2 , peeling occurs at the interface between the base material and the plating layer, which causes the problem of cracks in the plating layer when repeated contact loads are applied, and this condition progresses. This causes the plating layer to peel off from the base material, resulting in a significant decrease in wear resistance. On the other hand, the sliding surface was coated with Fe-Mo by thermal spraying or the like.
The method of coating with alloy, Fe-Cr alloy, etc. is undesirable because it increases the cost.
In addition, with regard to the resin coating method, if a material with good compatibility with oil is selected as the coating material, the oil lubricity between the shift fork and the sleeve fitted to it will be improved, and the wear resistance will be improved. However, in the case of such a resin coating, if the perpendicularity of the sliding surface of the shift fork pawl to the fork shaft hole is not sufficiently ensured, the coating may deteriorate due to contact with local parts. There is a problem that the resin is easily melted and damaged, resulting in a lack of durability. In addition, the shift fork, which is made of spheroidal graphite cast iron subjected to gas soft nitriding treatment, tuftride treatment, etc., to form an iron nitride layer on the sliding surface of the claw, is more resistant than steel sleeves that have been subjected to carburizing treatment, etc. It exhibits good characteristics in terms of wear resistance and conformability, but in the case of shift forks that are subjected to high loads, this nitride layer can only be formed on the sliding surface of the pawl by around 5 μm. If it wears out, there are inherent problems such as the wear progressing rapidly. The present invention has been made in view of the above circumstances, and its purpose is to:
The object of this invention is to significantly improve the wear resistance of the sliding surface of a cast iron gear shift fork with the gear coupling spring sleeve, and to make it possible to manufacture a shift fork with such high wear resistance at a relatively low cost. There is a particular thing. In order to achieve such an object, the present invention has made the sliding surface of the cast iron shift fork tip pawl that slides on at least the gear coupling sleeve with a laser beam,
After remelting with a high energy density source such as a TIG arc or an electron beam to form a cementite hardened layer on the surface layer of the sliding surface, a nitriding treatment is further performed to form a nitride layer. This allows for the use of low viscosity oil, etc.
For shift forks, which require high wear resistance due to poor lubrication conditions and considerable high loads, we have developed a shift fork that has significantly improved wear resistance and can be manufactured at a relatively low cost. That's what I did. DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a shift fork and a method for manufacturing the same according to the present invention will be described in more detail with reference to the drawings. In FIG. 1, reference numeral 1 denotes a shift fork made of cast iron, and its semicircular or horseshoe-shaped pawl tip portions 2 and 3 are used as sliding portions for a predetermined gear coupling sleeve. Note that 4 and 5 are forkshaft holes extending in a direction perpendicular to the drawing. By the way, such a shift fork 1
The material constituting the is cast iron, but spheroidal graphite cast iron (FCD) is generally used, and such spheroidal graphite cast iron usually has a carbon content of 3.2 to 4.0%.
Mn: 0.2~0.7%, P: 0.01~0.04%, S: 0.01~
0.03%, Si: 1.6 to 2.9%, and Fe: the balance, and the content of each component is determined as appropriate from within these ranges. Then, the molten metal containing each component that gives such a cast iron composition is cast into a shift fork mold according to a conventional method, thereby producing a cast material. Next, the obtained shift fork rough shape is heat treated, for example, held at a temperature of 930°C for 1 hour, and then air cooled, and after removing distortions received during casting, it is cut. Thus, a gear shift fork material having the shape shown in FIG. 1 is formed. In the present invention, for the gear shift fork material obtained in this way, at least the sliding surfaces 2 and 3 of the tip claw portion that slides on the gear coupling sleeve are laser (light beam), TIG (tungsten laser), etc.
By applying a high energy density source such as an inert gas arc or an electron beam to re-melt only the outermost layer, a cementite structure is crystallized and hardened in the melted area, thereby making the sliding A hardened cementite layer is formed on the surface layer of the surface. In addition, a high energy density source as described above is applied to the sliding surfaces 2 and 3 of the shift fork material, and
Generally, such a high energy density source will be maneuvered as a spot over the sliding surface at a predetermined speed. When a spot of such a high energy density source is applied, the surface layer of the cast iron structure in the vicinity is melted, but the shape of the spot, its scanning speed, the spacing of the scanning lines, etc. cannot be changed by the remelting operation. It is determined so that a predetermined molten layer is almost uniformly formed on at least the sliding surface of the shift fork to be applied. In addition, the thickness of the surface layer where the desired cementite structure is crystallized by being melted by such remelting operation is appropriately determined depending on the purpose, and for example, when the thickness reaches about 2 to 3 mm or more There are some, but in general
It is remelted at a thickness (depth) of about 0.5 to 1 mm, and a desired hardened layer is formed. Next, the gear shift fork material having the cementite hardened layer formed in this way on at least its sliding surfaces 2 and 3 is coated with 0.2 to remove some distortion generated on the sliding surfaces due to the remelting operation. After being polished to a depth of about 0.3 mm, a predetermined nitriding treatment is performed according to the present invention, whereby the remelted sliding surface portion, in other words, the hardened cementite layer is further nitrided. A physical layer is formed. The nitriding treatment does not need to be applied to the entire gear shift fork 1, and in some cases, it may be applied only to the sleeve sliding surfaces 2 and 3 of the gear shift fork 1, which are particularly prone to wear. In addition, various known methods can be used for the nitriding treatment, for example, at 500 to 600°C in an atmosphere containing ammonia gas.
Gas nitrocarburizing treatment, which is held at a certain temperature for a predetermined period of time, and tuftride treatment, which uses a salt bath, are employed. The thus obtained gear shift fork has a hardened cementite layer formed by remelting and a nitride layer formed on the hardened cementite layer on at least the sliding surface of the tip claw that slides on the gear coupling sleeve. Therefore, its wear resistance properties are greatly improved, and its durability is also excellent. Further, according to the present invention, by remelting and hardening the surface of the sliding part of the shift fork to a minimum using a simple device, a good gear shift fork with significantly improved initial conformability and wear resistance is provided. It had become a thing. Incidentally, FIG. 2 shows a comparison of the wear resistance between the shift fork according to the present invention manufactured in this manner and a conventional shift fork. In the figure, A is an S55C product that has been induction hardened, B is a cast iron product that has been induction hardened, C is a cast iron product that has been chromed, and D is a cast iron product that has been subjected to gas nitrocarburizing treatment. is the conventional product or comparative product), and E is the inventive product, and the test results of the amount of wear (wearing thickness) against the total frictional work when these were assembled into the transmission are shown in Figure 2. are illustrated in each. In addition, in the product E of the present invention, a gear shift fork material made of graphite spheroidal cast iron is welded using an arc using a TIG welder, and its sliding surfaces 2 and 3 are welded under the conditions shown in the table below:
【表】
にて再溶融され、セメンタイト組織を晶出させて
硬化せしめた後、0.2〜0.3mmの研摩加工を施し、
更にアンモニアガス：窒素ガス＝１：１からなる
雰囲気下、温度560〜580℃、3.0時間なる条件下
で保持し、徐冷することにより、ガス軟窒化処理
を施したものである。また、それらの試験条件は
次の通りであり、更に総摩擦仕事量（Kg・ｍ）は
下式に従つて求められたものである。
総摩擦仕事量（Kg・ｍ）＝スリーブの周速（ｍ／sec）×１サイクルの荷重と時間（Kg・sec）
×全サイクル（繰り返し回数）
(1) プロペラシヤフト回転数（周速）：4000r.p.
m（20m／sec）
(2) シンクロレバー上荷重：５Kg（接触荷重は50
Kg／cm2）
(3) 負荷時間：2.5sec
(4) 負荷サイクル：22000回
(5) 油温：85〜90℃（SAE＃90ギヤオイル）
第２図から明らかなように、本発明によるシフ
トフオークＥは、他の従来のものに比べて摩耗量
が大巾に減少しており、しかもある一定の総摩擦
仕事量に達すると収斂してそれ以上の摩耗量の増
加がなくなることが判明したのである。またクロ
ムメツキ品であるシフトフオークＣにおいては、
総摩擦仕事量が略５×10-6Kg・ｍとなると、クロ
ムメツキ層の剥離が生じ、異常摩耗が開始された
ことが認められ、またガス軟窒化品であるシフト
フオークＤにあつても、総摩擦仕事量が略６×
10-6Kg・ｍに達すると、ガス軟窒化によつて形成
された窒化層が消失し、異常摩耗が惹起されるこ
とが認められた。
以上詳述したように、本発明に従つて、ギヤカ
ツプリングスリーブと摺動する少なくともシフト
フオーク先端爪部の摺動面に、再溶融によつてセ
メンタイト硬化層を形成し、更にその上に窒化物
層を形成せしめることによつて、耐摩耗特性は著
しく向上され、またその耐久性も著しく向上され
得ることとなつたのであり、しかもそれが再溶融
操作と窒化処理との比較的簡単な手法によつて達
成され得ることとなつたのであつて、そこに本発
明の大きな工業的意義が存するものである。[Table] After being remelted and hardened by crystallizing the cementite structure, it was polished to a depth of 0.2 to 0.3 mm.
Further, the material was subjected to gas nitrocarburizing treatment by holding it at a temperature of 560 to 580 DEG C. for 3.0 hours in an atmosphere consisting of ammonia gas:nitrogen gas=1:1, and slowly cooling it. The test conditions are as follows, and the total frictional work (Kg·m) was determined according to the formula below. Total frictional work (Kg・m) = Sleeve circumferential speed (m/sec) × Load and time for 1 cycle (Kg・sec) × Total cycle (number of repetitions) (1) Propeller shaft rotation speed (circumferential speed): 4000r.p.
m (20m/sec) (2) Load on synchro lever: 5Kg (contact load is 50
Kg/cm 2 ) (3) Load time: 2.5sec (4) Load cycle: 22000 times (5) Oil temperature: 85-90℃ (SAE #90 gear oil) As is clear from Figure 2, the shift according to the present invention It was found that the amount of wear of Fork E was significantly reduced compared to other conventional products, and that once a certain amount of total friction work was reached, the amount of wear converged and there was no further increase in the amount of wear. It is. In addition, in Shift Fork C, which is a chrome plated product,
When the total frictional work amount was approximately 5×10 -6 Kg・m, it was observed that the chrome plating layer peeled off and abnormal wear began. Total frictional work is approximately 6×
It was observed that when the temperature reached 10 -6 Kg·m, the nitride layer formed by gas nitrocarburizing disappeared, causing abnormal wear. As described in detail above, according to the present invention, a hardened cementite layer is formed by remelting on the sliding surface of at least the tip claw portion of the shift fork that slides on the gear coupling sleeve, and furthermore, a hardened cementite layer is formed on the sliding surface of the tip claw portion of the shift fork that slides on the gear coupling sleeve. By forming this layer, the wear resistance properties and durability could be significantly improved, and it was possible to do so using a relatively simple method of remelting and nitriding. This has been achieved by the method of the present invention, and this is where the great industrial significance of the present invention lies.
第１図は本発明に係るギヤシフトフオークの一
実施例を示す平面図、第２図は本発明に係るギヤ
シフトフオークと従来例（４種）との耐摩耗特性
を比較したグラフである。
１：シフトフオーク、２，３：爪部先端部分、
４，５：フオークシヤフト穴。
FIG. 1 is a plan view showing an embodiment of a gear shift fork according to the present invention, and FIG. 2 is a graph comparing the wear resistance characteristics of the gear shift fork according to the present invention and conventional examples (four types). 1: Shift fork, 2, 3: Tip of claw,
4, 5: Forkshaft hole.
Claims (1)
する、鋳鉄製シフトフオーク先端爪部の摺動面
が、レーザ、TIGアーク、電子ビーム等の高エネ
ルギー密度源による再溶融にて該摺動面の表層部
に形成されたセメンタイト硬化層と、該セメンタ
イト硬化層の上に更に形成された窒化物層とから
構成されていることを特徴とする鋳鉄製ギヤシフ
トフオーク。1 At least the sliding surface of the cast iron shift fork tip pawl that slides on the gear coupling spring sleeve is remelted by a high energy density source such as a laser, TIG arc, or electron beam to form a surface layer of the sliding surface. A cast iron gear shift fork comprising a hardened cementite layer and a nitride layer further formed on the hardened cementite layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13435482A JPS5923867A (en) | 1982-07-30 | 1982-07-30 | Gearshift fork made of cast iron |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13435482A JPS5923867A (en) | 1982-07-30 | 1982-07-30 | Gearshift fork made of cast iron |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5923867A JPS5923867A (en) | 1984-02-07 |
| JPS6221071B2 true JPS6221071B2 (en) | 1987-05-11 |
Family
ID=15126401
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13435482A Granted JPS5923867A (en) | 1982-07-30 | 1982-07-30 | Gearshift fork made of cast iron |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5923867A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0333261U (en) * | 1988-05-25 | 1991-04-02 | ||
| JPH0271169U (en) * | 1988-11-17 | 1990-05-30 | ||
| CN108149244A (en) * | 2017-12-26 | 2018-06-12 | 高飞 | A kind of high-performance shifting fork device and its surface treatment method |
-
1982
- 1982-07-30 JP JP13435482A patent/JPS5923867A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5923867A (en) | 1984-02-07 |
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