JPS5813227A - Oilless bearing - Google Patents

Abstract

PURPOSE:To use effectively a lubricating oil, by composing a bearing of a synthetic resin serving as base resin into which inorganic porous particles for carrying the lubricating oil, oil transferring fibers and a metal powder are uniformly dispersed. CONSTITUTION:An oilless bearing 1 comprises the synthetic resin 6 serving as a base resin into which 1-40vol% lubricating oil 2, 1-20vol% inorganic porous particles 3 (that absorb and carry the lubricating oil 2), 5-30vol% lubricating oil transferring fibers 4 (that act as agent for transferring the lubricating oil 2 carried on the inorganic porous particles 3) and 0.5-50vol% metal powder (that comprises sprayed kelmet powder or bronze powder) are mixed.

Description

【発明の詳細な説明】 この発明社無給油軸受に関する。[Detailed description of the invention] This invention relates to an oil-free bearing.

従来、軽負荷用無給油軸受として自己潤滑性と耐摩耗性
に優れた物性を有する合成樹脂、例えばポリアミド、ポ
リアセテート、ポリアセタール、ポリブチレンフタレー
ト、ポリカーボネート、ポリテトラフルオロエチレン等
により成形したも゛のボ知られている。Conventionally, oil-free bearings for light loads have been made of synthetic resins with excellent physical properties such as self-lubrication and wear resistance, such as polyamide, polyacetate, polyacetal, polybutylene phthalate, polycarbonate, polytetrafluoroethylene, etc. Bo is known.

こｔｔｂ合成樹脂製の無給油軸受の使用範囲をより高負
荷のものに拡げるため、種々の試みがな′□され゛てお
り、これら試みのうちすでに最も効果のあるものとして
は、上記゛合成樹脂中に、潤滑油を活性炭、合成ゴムな
どの吸収剤に吸収させて混人し二上記合成樹脂の有する
物性に、潤滑油の機能を付加させ得るようにしたものが
提案され、かつ実施されている。Various attempts have been made to expand the scope of use of oil-free bearings made of synthetic resin to higher-load applications, and among these attempts, the most effective one is the above-mentioned synthetic resin bearing. It has been proposed and implemented that a lubricating oil is mixed with an absorbent such as activated carbon or synthetic rubber in a resin so that the physical properties of the above-mentioned synthetic resin can be added with the function of a lubricating oil. ing.

しかしながら、上記潤滑油吸収剤の潤滑油液′収能は一
般に□低く、潤滑油ｌ容量に対し、吸収量は“３容量程
度であり、大量の潤滑油を吸収させたい場”合一自から
潤滑油吸収剤め使用量讐増加せねばガらず、′・これが
軸受のペースレジンの物性低下の原因□となるといった
欠点があった。However, the lubricating oil absorption capacity of the above lubricating oil absorbent is generally low, and the absorption amount is about 3 volumes per 1 volume of lubricating oil, so if you want to absorb a large amount of lubricating oil, The amount of lubricating oil absorbent used has to be increased, which has the disadvantage of causing a decline in the physical properties of the bearing's paste resin.

一方、上記のように、大量の潤滑油を軸受体動面に有効
に浸出される潤滑油は、第１図に示すように軸受Ａの摺
動面Ｂに表出する吸収剤０に担持された潤滑油に限られ
、他のもの０゛は軸受Ａを形成するペースレジンＤ内に
閉じ込められて有効に利用できないといった問題がある
。On the other hand, as mentioned above, a large amount of lubricating oil that is effectively leached onto the bearing body moving surface is carried by the absorbent 0 exposed on the sliding surface B of the bearing A as shown in FIG. There is a problem in that the lubricating oil is limited to the lubricating oil, and the other lubricating oils are trapped in the pace resin D forming the bearing A and cannot be used effectively.

又、合成樹脂の物性及び潤滑ｉとの協働によ□　リ、低
摩擦性が向上されたといっても、ある程度の摩擦熱の発
生は防止できず、従って、合成樹脂は熱膨張率が大きく
、熱伝導率が低いため使用条件に応じ熱膨張率を見込ん
だ寸法に成形する必要があり、寸法設定に高度な技術と
経験を要するといった欠点があった。In addition, even though the physical properties of synthetic resins and the cooperation with lubricants have improved low friction, it is not possible to prevent the generation of frictional heat to some extent, and therefore synthetic resins have a large coefficient of thermal expansion. However, due to its low thermal conductivity, it had to be molded to dimensions that took into account the coefficient of thermal expansion depending on the conditions of use, and it had the disadvantage of requiring advanced technology and experience to set the dimensions.

□鑑み、軸受を形成する合成 樹脂中に少量の一一□剤により大量の潤滑油を吸収させ
得ると共に・これ、、、’、、、？、吸収剤を介して含
ませた潤滑油がはぼ完全に使用されつくされ、し１十 かも軸受を形成する合成樹脂の物性を熱による影響を受
けにくいものとすることにより成形容易な無給油軸受を
得ることを目的としてなされたものであって、１〜４０
容積％の潤滑油と、該潤滑油担体として０．１〜２０容
積％の無機多孔質粒体と、該無機多孔質粒体に担持させ
た潤滑油の導□通材として５〜３０容積％の導油性短繊
維と、０．５〜５０容積％の金属粉と、残部容積−の合
成樹脂とから形成されたことを特徴とするものである。□In view of this, a large amount of lubricating oil can be absorbed by a small amount of lubricant into the synthetic resin that forms the bearing, and...? The lubricating oil impregnated through the absorbent is almost completely used, and the physical properties of the synthetic resin that forms the bearing are made less susceptible to heat, making it easy to mold without oil. It was made for the purpose of obtaining bearings, and has a diameter of 1 to 40
% by volume of lubricating oil, 0.1 to 20 vol. % of inorganic porous particles as a carrier for the lubricating oil, and 5 to 30 vol. It is characterized by being formed from oil-based short fibers, 0.5 to 50% by volume of metal powder, and the remaining volume of synthetic resin.

次に、この発明を実施例により説明する。Next, the present invention will be explained using examples.

第、２図はこの発明の実施例の要部拡大断面図゛二、コ
ｍｍｍ１ｄｌ！　ｌ　１１．１ｍ？１ｍ　２　ｔ＊＠、
担持する無機多孔質粒体３、導油性繊維４、及び金属粉
５が、軸受ｌのペースレジンとなる合成樹脂６内に均一
分散されて混入されて形成されている。　　″ 上記において゛・９、潤滑油は、スピンド、導油、り５
・冨 °・、１ 一ビン油、マシン油、ダイナモ油等の芳香族系潤滑油、
ナフテン系潤滑油、パラフィン系潤滑油、又は炭化水素
、エステル、ポリグリプール、シリコーン等の合成油な
ど一般に使用されて−る潤滑油であれば何でも良い。FIG. 2 is an enlarged sectional view of the main part of the embodiment of this invention. l 11.1m? 1m 2 t*@,
The supporting inorganic porous particles 3, oil-conducting fibers 4, and metal powder 5 are uniformly dispersed and mixed into a synthetic resin 6 that serves as the paste resin of the bearing 1. ``In the above, ゛・9, lubricating oil is spindle, oil guide, ri5
・Fu°・, 1 Aromatic lubricating oil such as bottle oil, machine oil, dynamo oil, etc.
Any commonly used lubricating oil may be used, such as naphthenic lubricating oil, paraffinic lubricating oil, or synthetic oils such as hydrocarbon, ester, polyglypur, and silicone oils.

この潤滑油２の添加量は１〜４０容積襲とされるが、こ
の理由は、ｌ容積（■少ないと充分な潤滑性が期待し得
ず、又、４ｏ容積％を超えると後述する導油性繊維との
関係より潤滑油流出が著しくなり、潤滑油増量の意味が
なくなるからである。The amount of lubricating oil 2 added is said to be 1 to 40% by volume. This is because lubricating oil leakage becomes significant due to the relationship with fibers, and there is no point in increasing the amount of lubricating oil.

無機多孔質粒体３としては、きわめて空隙性の、高い結
晶構造を有する無機多孔質粒体、例えばパーライト、珪
藻土、珪藻土とシリカと水和した石灰及び水熱反応によ
る合成水利カルシウムシリケート類、天然又は合成のゼ
オライト、さらにはガラス焼結製沸とう石などの多孔質
の微粒子体が用いられる。　　　　　　、これらのもの
は、結晶、構造により潤滑油吸収率が良く、例えば従来
の活性外、合成ゴムなど゛　の潤滑油吸収能１が１容量
一対し潤滑油３容量であるのに対し、上記無機多孔質粒
体３はｌ容量に対し、潤滑油ｌＯ容量にまで達する。The inorganic porous particles 3 include highly porous inorganic particles having a highly porous crystal structure, such as perlite, diatomaceous earth, diatomaceous earth, lime hydrated with silica, and synthetic water-use calcium silicates by hydrothermal reaction, natural or synthetic. Porous fine particles such as zeolite and glass sintered fluorite are used. These materials have a good lubricating oil absorption rate due to their crystals and structure.For example, while the lubricating oil absorption capacity of conventional inorganic rubber and synthetic rubber is 1 volume to 3 volumes of lubricating oil, the above-mentioned inorganic The porous granules 3 have a lubricating oil lO capacity compared to l capacity.

従って、従来と同量の潤滑油を吸収させるには潤滑油吸
収剤の使用が−になり、ベースレジンである合成樹脂６
の物性低下の影響が少なくなる。　　　　　　　　　　
　　　　　　　　　・従って、無給油軸受の構成素材全
体を１００容　−積一と（た場合、潤滑油１〜４０容積
％に対、し、無機多孔質粒体を０．１〜２０容積−とす
れば十分である。尚、潤滑油祉上記無機多孔質粒体の量
であればさらに多−量のものを含有させる仁とができ、
るボ、あま抄多くする、と、含有過多による流中が著し
くなるため、潤滑油量を４０容積襲前後を上限とするの
が適当である。　　　　　　“又、潤滑油４通材として
用いられる親油性のあ今繊維′４としては１．油と親和
性を有する繊維。Therefore, in order to absorb the same amount of lubricating oil as before, the use of a lubricating oil absorbent becomes negative, and the base resin, synthetic resin 6
The effect of deterioration of physical properties is reduced.
・Therefore, it is sufficient that the entire constituent material of an oil-free bearing has a volume of 100 - 1 (in this case, lubricating oil has a volume of 1 to 40%, and the inorganic porous particles have a volume of 0.1 to 20 volume). However, if the lubricating oil has the above-mentioned amount of inorganic porous particles, it is possible to contain an even larger amount of the inorganic porous particles.
If the amount of lubricant is increased, the amount of lubricant in the lubricant will become excessively large, so it is appropriate to limit the amount of lubricating oil to around 40 volume. "Also, the lipophilic oil fibers used as a lubricating oil material are: 1. Fibers that have an affinity for oil.

例えば炭素繊維等の無機繊維、あるーは麻、綿。For example, inorganic fibers such as carbon fiber, linen, and cotton.

羊毛等の天然繊維１、又、油との親和性を有するポリア
ミド゛、ポリカーボネート、ポリプロピレン、セルロー
ス等の合成繊維が用いられ、その長さは軸受の大きさに
もよるが、潤滑油吸収剤としての無機多孔質粒体３０分
布率により確率的にこれらの粒体Ｐ間に横架し得る長さ
の短繊この短繊維４は前記無機多孔質粒体３に吸収させ
た潤滑油２を軸受ｌの摺動面ｌ゛へと流通させるため添
加されるものであり、５容積％より少ないと充分な潤滑
油流通性が保たれず、又、３０容積％より多いと潤滑油
の流通性が過剰となり、潤滑油の流失量が増加する′一
方、軸受の成形用合成樹脂（ベースレジン）６の物性低
下の原因となるため、上記範囲内の添加量とする′尚、
導油性繊維４として、上記繊維のほか、第１３図に示す
ような中空糸４Ａ この中空糸４Ａとは、限外濾過器などに使用される透過
用支持管などの中空と亭れた繊維であって、その牟空壁
＋ｉに坪、′微小なミクロ的透過孔４Ｂが無数に存在す
る中：・□横状繊維を言い、これを短く裁断し短繊維化
したものが用いられる。Natural fibers such as wool1 and synthetic fibers such as polyamide, polycarbonate, polypropylene, and cellulose that have an affinity for oil are used, and their length depends on the size of the bearing, but they can be used as lubricating oil absorbers. The short fibers 4 have a length that can be probabilistically crossed between these particles P depending on the distribution rate of the inorganic porous particles 30. It is added to distribute the lubricating oil to the sliding surface. If it is less than 5% by volume, sufficient lubricating oil distribution will not be maintained, and if it is more than 30% by volume, the lubricating oil will have excessive distribution. This increases the amount of lubricating oil lost and causes a decrease in the physical properties of the synthetic resin (base resin) 6 used for molding the bearing, so the amount added should be within the above range.
In addition to the above-mentioned fibers, the oil guiding fibers 4 include hollow fibers 4A as shown in FIG. There are countless microscopic permeable holes 4B in the hollow wall +i. □Horizontal fibers are used, which are cut into short lengths and made into short fibers.

４に属粉５としては、噴霧ケルメツト粉又は青銅粉が使
用される。これらの金属粉は軸受１の熱膨張係数の低下
、熱伝導率の向上を図り、もって寸法安定性を良くする
ものであって、その配合はできるだけ多いことが望まし
ψが、容積％にして５０容積％をこえて添加しても効果
の向上はそれ程期待できない反面、軸受体の組織構造が
急激にもろくなり、成形が困難となる傾向を生じるため
、０．５〜５０容積傳の範囲とするのが最適である。As the powder 5 of 4, sprayed kelmet powder or bronze powder is used. These metal powders aim to reduce the thermal expansion coefficient and improve the thermal conductivity of the bearing 1, thereby improving the dimensional stability.It is desirable that the proportion of these metal powders is as large as possible, and ψ is expressed as volume %. Adding more than 50% by volume will not significantly improve the effect, but on the other hand, the structure of the bearing body will suddenly become brittle, making molding difficult. It is best to do so.

又、合成ｌ脂６は、軸受１を成形する基礎材料となるも
の 一ト、ポリアセタール、ポリブチレンフタレート、ポリ
カーボネート、ポリテトラフルオロエチレンなどの自己
潤滑性と耐摩耗性に優れたも次に、こめ発明９作用につ
いて説明する。In addition, the synthetic lubricant 6 is a base material for forming the bearing 1, and is also made of materials with excellent self-lubricating properties and wear resistance, such as polyacetal, polybutylene phthalate, polycarbonate, and polytetrafluoroethylene. The effect of invention 9 will be explained.

この発明の無給蔓軸受１は環状に成形され、内面を摺動
面ｌ“とじて第４図に示すように、軸受部Ｅに装着され
、回転軸ｒを受容する。尚、図中Ｅ１はプツシ、Ｌであ
る。The free helical bearing 1 of the present invention is formed into an annular shape, and the inner surface is closed with a sliding surface l'', and as shown in FIG. Pushsi, L.

第２図又は第４図において゛、軸受摺動面ｌ°は低摩、
擦性及び耐摩耗性に優れた合成樹脂面とされ、その表面
ｌ°にはここに表出した無機多孔質粒体３に吸収、担持
させた潤滑油が供給されるので、これらが相乗、して軸
受摺動面１゛の潤滑性がきわめて良好に保たれる。又、
軸受摺動面よ抄直接供給される潤滑油ＩＡが消費されて
も軸受ｌ内に混入した導油性繊維２を介して潤滑油が順
次摺動面１°へと導かれ、軸受体内に閉じ込められた状
態にある潤滑油も有効に利用、されるのである。In Fig. 2 or 4, the bearing sliding surface l° has low friction.
It has a synthetic resin surface with excellent abrasion and wear resistance, and lubricating oil absorbed and carried by the inorganic porous particles 3 exposed here is supplied to the surface l°, so these synergistically As a result, the lubricity of the bearing sliding surface 1' is maintained extremely well. or,
Even if the lubricating oil IA that is directly supplied to the bearing sliding surface is consumed, the lubricating oil is sequentially guided to the sliding surface 1° through the oil-conducting fibers 2 mixed inside the bearing 1 and is trapped inside the bearing body. Even lubricating oil that is in a dry state can be used effectively.

一方、軸受体内に摩擦熱による熱蓄積があっても、内部
に混入した金属粉５により伝熱率が高くされ、内部が著
しく高温化してしまうのをである。On the other hand, even if heat is accumulated in the bearing body due to frictional heat, the heat transfer rate is increased by the metal powder 5 mixed inside, and the temperature inside the bearing body becomes extremely high.

次に、この発明の具体的な実施例について説明する。Next, specific embodiments of the present invention will be described.

実施例１　　　　　　　　　　　　　　　　．１１滑油
（商品名：ダフニースーパーメカニツクオイル１ｏｏ　
）　３ｏ容積％を平均粒子径５０μとされた合成ゼオラ
イト（商品名：モレキュラシープ）ｌｏ′容積％に含浸
させ、これを炭素繊維１０容積％゛、噴霧ケルメツト粉
１０容積％、ポリアセタール樹脂粉末４０容積％と共に
混合し、押出機によりベレットとした後、射出成形に上
り所定形状′の軸受を成形した。Example 1. 11 Lubricating oil (Product name: Daphne Super Mechanic Oil 1oo
) 3o volume% was impregnated into synthetic zeolite (trade name: Molecular Sheep) lo' volume% with an average particle size of 50μ, and this was impregnated with 10% by volume of carbon fiber, 10% by volume of sprayed Kelmet powder, and 40% by volume of polyacetal resin powder. The mixture was mixed with a volume percentage and made into pellets using an extruder, and then injection molded to form a bearing of a predetermined shape.

実施例２ 潤Ｎ油（’ＭＡ　品名’ダフニースーパーメカ；ツクオ
イルｌｏｏ　）　２５容積％を平均粒子径４５μとされ
たパーライト粒子１２．５容積％に含浸させ、こＫと炭
素繊維１８容積％、噴霧ケルメツト粉８容積襲、ポリブ
チレンテレフタレート３６．５容積％と共に混合し、押
出機によりペレットとした後射出成形により所定形状の
軸受を　、゛成形した。　。Example 2 12.5 volume % of perlite particles with an average particle size of 45 μm were impregnated with 25 volume % of Lune N oil ('MA product name' Daphne Super Mecha; Tsuku Oil Loo), and 18 volume % of carbon fiber and sprayed. The mixture was mixed with 8 volumes of Kelmet powder and 36.5% by volume of polybutylene terephthalate, made into pellets using an extruder, and then molded into bearings of a predetermined shape by injection molding. .

′：工。ｍ　ａａ　：　Ｉ”　７　＝　−ｘ　−ｔ、−
７＊　、Ｗ　７クオイル１ｏｏ　）　３ｏ容積％を合成
カルシウムシリケート（四品名：ミクロセル）１５容積
％に含浸させ、これをセルロース繊維１ｏ容積％、青銅
粉１０容積％、ポリアセタール樹脂粉末３５容積％と混
合し゛、押出機によりベレットとした後、射出成形によ
り所定形状の軸受を成形した。′: Engineering. m aa: I” 7 = −x −t, −
7*, W 7 Quoyle 1oo ) 3o volume % was impregnated into 15 volume % of synthetic calcium silicate (4 product names: Microcell), and this was mixed with cellulose fiber 1o volume %, bronze powder 10 volume %, and polyacetal resin powder 35 volume %. After forming a pellet using an extruder, a bearing of a predetermined shape was formed by injection molding.

実施例４ 潤滑油（商品名：ダフニースーパーメカニックオイル１
ｏｏ　）　２０容積％を平均粒子径１５０μのガラス焼
結溝とう石（商品名：ボイルストーン）１０容積％に含
浸させ、これと中空糸（商品名：ホローファイバー）の
径０．５　ｍｓ長さ０．５〜１ｍｓのものを１０容積％
、噴霧ケルメツト粉ｌＯ容積係、及び超高分子量ポリエ
チレン４０容積％とを混合し、押出機によりベレットと
した後、射出成形により所定形状の軸受を形成した。Example 4 Lubricating oil (product name: Daphne Super Mechanic Oil 1
oo ) 20% by volume is impregnated into 10% by volume of glass sintered stone (trade name: Boil Stone) with an average particle diameter of 150μ, and this and a hollow fiber (trade name: Hollow Fiber) with a diameter of 0.5 ms and a length of 10% by volume of 0.5-1ms
, atomized Kelmet powder by volume, and 40% by volume of ultra-high molecular weight polyethylene were mixed to form a pellet using an extruder, and then a bearing of a predetermined shape was formed by injection molding.

、　　上記実施例にお―て成形した軸受体はいずれも８
酩φＸ１０ｓｓφＸ１５鴎の寸：′・凍のものであり、
これに８４５０焼入れなし、表面あらさ３ｓの軸を受容
させ、次の試験条件のもとて摩擦、摩耗試験を行った。, All the bearing bodies molded in the above examples were 8
酩φX10ssφX15 The size of the seagull: '・It is frozen,
A 8450 unquenched shaft with a surface roughness of 3s was received on this shaft, and friction and wear tests were conducted under the following test conditions.

試験条件 り軸荷重　５７９／Ｃ１！　３０００　ｒｐｍ、２．　
　　　＃　　　　　　ｚｋｇｙａ！　　７５ｏｏｒｐｍ
３、　運転ｉ続時間− 試験結果 ＊単位　Ｘｌ０−’ｇｍ／ｋｇ−ａｍ−２−ｍ　＠ｍ１
ｎ−’　−ａｒ上表における比較例は、プリアセタール
樹脂を潤滑油と共に一合成！シたものである。Test conditions: Axial load 579/C1! 3000 rpm, 2.
#zkgya! 75oorpm
3. Duration of operation - Test result * Unit Xl0-'gm/kg-am-2-m @m1
The comparative example in the n-'-ar table above is a synthesis of preacetal resin and lubricating oil! It's something new.

本実明祉以上のように画成されているので、・、−、＋ 軸受内に混入し、た５、担体から親油性を有する短繊維
を介して＾滑油が軸受摺動面へと流通されるので、上記
実験結果よりも明らかなように高負荷条件のもとであっ
ても摩擦による温度上昇並びに摩耗が従来例のものに比
しいちじるしく少なく、又、金属粉の使用により、寸法
安定性が向上し、温度上昇による変形等も極めて少なく
でき、長期にわたって安定した機能を発揮するのである
。Since the present invention is defined as described above, -, -, + are mixed into the bearing, and lubricating oil is transferred from the carrier to the bearing sliding surface via short fibers with lipophilic properties. As is clear from the above experimental results, the temperature rise due to friction and wear are significantly lower than those of conventional models even under high load conditions, and due to the use of metal powder, the size This improves stability, minimizes deformation due to temperature rise, and provides stable functionality over a long period of time.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は従来例の説明図、第２図社実施例の拡大断面図
、第３図は実施例の要部拡大断面図、第一図は使用状態
を示す説明図である。 ｌ・・・無給油軸受、２・・・潤滑油、３・・・無機多
孔質粒体、４・・・導油性繊維、５・・・金属粉、６・
・・合成樹脂。 りFIG. 1 is an explanatory diagram of a conventional example, FIG. 2 is an enlarged sectional view of an embodiment, FIG. 3 is an enlarged sectional view of a main part of an embodiment, and FIG. 1 is an explanatory diagram showing a state of use. 1... Oil-free bearing, 2... Lubricating oil, 3... Inorganic porous granules, 4... Oil-conducting fiber, 5... Metal powder, 6...
・Synthetic resin. the law of nature

Claims (1)

【特許請求の範囲】[Claims] （１）１〜４０容積％の潤滑油と、皺潤滑油担体として
０１ｌＮ２０容積％の無機多孔質粒体と、該無機多孔質
粒体に担持させた潤滑油の導通材として５〜３０容積−
％の導油性短繊維と、０．５″□〜５０□〜５０容積と
、残部容積％の合成樹脂と力＝ら形成されたことを特徴
と゛する無給油□軸受。　　　　　　　　　　　　　　
　　　・　　　パ（２）　　導油性短繊維が中空糸を短
繊維状に裁断したも□”のである特許請求の範囲第１項
記載の無給油軸受。　　　　　　　　　　　　　　′・
□（３）導油性短繊維が油との親和□性を有する天然１
又は合成繊維である特許請求の範囲第１項記載の無給油
軸受。(1) 1 to 40 volume % of lubricating oil, 20 volume % of inorganic porous particles as wrinkled lubricant carrier, and 5 to 30 volume as a conductive material for lubricating oil supported on the inorganic porous particles.
% of oil-conducting short fibers, a volume of 0.5''□ to 50□ to 50%, and the remaining volume % of a synthetic resin.
・Pa(2) The oil-free bearing according to claim 1, wherein the oil-conducting short fibers are hollow fibers cut into short fibers.
□(3) Oil-conducting short fibers have affinity with oil □Natural 1
or a synthetic fiber, the oil-free bearing according to claim 1.