JP3681022B2 - Rolling bearing - Google Patents

Description

【００２２】
【化２】

【００２３】
【化３】

【００２４】
前述の官能基付きの含ふっ素重合体として、より詳しくは、パーフルオロポリエーテル（ＰＦＰＥ）あるいはその誘導体との混合物、具体的に例えばモンテカチーニ社の商品名フォンブリン（FONBLIN）Ｙスタンダード、フォンブリンエマルジョン（FE20、EM04など）またはフォンブリンＺ誘導体（FONBLIN Z DEAL、FONBLIN Z DIAC、FONBLIN Z DISOC、FONBLIN Z DOL、FONBLIN Z DOLTX2000、FONBLIN Z TETRAOLなど）が好適に用いられる。これら例示したものは、いずれも濃度が濃く、金属に対する親和性がきわめて悪いので、そのままでは膜状に付着させることが困難である。そのため、下記するような方法で形成するのが好ましい。
【００２５】
次に、上述した潤滑膜５の形成方法の一例を説明する。
【００２６】
（ａ） 内・外輪１，２、転動体３および保持器４をそれぞれ組み立てて転がり軸受Ａを完成状態としてから、この内・外輪１，２間で転動体３の存在する箇所において、用意した溶液をスポイドなどにより数滴、注入し、数回回転させることにより、内・外輪１，２および保持器４の転動、摺動部位と転動体３の表面とに液状膜を付着させる（付着処理）。この溶液の付着はスプレーを用いて行うこともできるし、また、溶液中に浸漬してもよい。ここで用意する溶液は、例えばフォンブリンエマルジョンＦＥ２０（フォンブリン濃度２０ｍａｓｓ％）を適当な希釈溶媒でフォンブリン濃度を０．２５ｍａｓｓ％にまで希釈したものである。なお、前述の希釈溶媒は、メタノール溶液、アルコール溶液や水などの揮発性のものとすることができる。
【００２７】
（ｂ） 液状膜を付着した転がり軸受Ａの全体を４０〜５０度で約３分間加熱し、液状膜に含む溶媒を除去する（乾燥処理）。
【００２８】
（ｃ） この後、軸受使用環境での雰囲気温度を考慮して、例えば１５０〜３００度で１５〜３０分間、加熱する（仕上げ乾燥処理）。例えば、歯科用ハンドピース５０では、例えば１３５℃〜１８０℃以上の高温蒸気にて滅菌処理（オートクレーブ処理）が行われるので、この温度を考慮すればよい。これにより、転がり軸受Ａの動作時や前述した滅菌処理時に溶媒や油成分などの不要な発塵がない流動性を有する潤滑膜５が得られる。
【００２９】
このようにすれば、転がり軸受Ａの構成要素の転動、摺動部位に潤滑膜５を好適な膜厚で形成することができる。なお、（ａ）、（ｂ）は必要に応じて数回繰り返すようにしてもよく、最終的には、潤滑膜５の膜厚を例えば０．２μｍ以下に設定する。但し、使用潤滑油の性状、膜形成方法や生成後の膜厚などは、適宜に設定すればよい。
【００３０】
以上説明した転がり軸受Ａでは、発塵性および潤滑性に関して格段に優れる潤滑膜５を形成しているから、転がり軸受Ａに対する潤滑剤供給を忘れるなどして、軸受内部の潤滑剤が枯渇したときでも、保持器４と内輪１または外輪２とが潤滑膜５を介して摺接することになり、それらの直接接触を防止するので、該摺接部位が早期段階ではほとんど摩耗せずに済む。しかも、このような潤滑剤の枯渇状態での使用時間が経過するに従い、トルク増加が起こって回転速度が低下するとともに発生音が変化することになるので、この変化によって潤滑剤の供給忘れを作業者に気付かせることが可能となる。このとき、潤滑膜５によって軸受構成要素を保護しているので、焼き付きに至らずに済み、後で潤滑剤を供給したとき、通常どおりに動作させて再使用できるようになる。
【００３１】
なお、本発明は上記実施例のみに限定されるものではなく、種々な応用や変形が考えられる。
【００３２】
（１） 上記実施例では、軸受形式として深溝型玉軸受を引用しているが、その他の種類の転がり軸受に本発明を適用できる。
【００３３】
（２） 上記実施例では、潤滑膜５を内・外輪１，２、転動体３、保持器４のすべてに形成しているが、少なくとも内・外輪１，２だけ、あるいは保持器４だけに形成することができる。
【００３４】
（３） 上記実施例では、潤滑膜５を内輪１の外周面と、外輪２の内周面と、転動体３および保持器４の表面全体とに形成しているが、内・外輪１，２の表面全体にも形成してもよい。この場合、例えば上記（ａ）の処理において用意する溶液中に、内・外輪１，２、転動体３、保持器４を個別に浸漬するか、あるいはそれらを組み立てた完成状態の軸受Ａを浸漬すればよい。また、潤滑膜５は、保持器４の案内形式に応じて、該当する面（例えば内輪案内の場合だと内輪１の軌道を除く外周面、外輪案内の場合だと外輪２の軌道を除く内周面）にのみ形成してもよい。さらに、潤滑膜５は、保持器４の案内面（内輪案内の場合だと内周面、外輪案内の場合だと外周面）のみに形成してもよい。
【００３５】
（４） 上記実施例では、転がり軸受Ａとして密封装置を持たない開放形のものを例示しているが、密封装置を装着したものとしてもよい。
【００３６】
（５） 上記実施例では、流動性を有する潤滑膜５を示しているが、下記するような固体状の潤滑膜５も本発明に含む。図３は、固体状の潤滑膜の構造を模式的に表した構造図、図４は、固体状の潤滑膜の硬化前の状態での性状分析結果を示すグラフ、図５は、固体状の潤滑膜の硬化後の状態での性状分析結果を示すグラフである。
【００３７】
前述の固体状の潤滑膜５は、末端がイソシアネート官能基付き含ふっ素重合体を硬化処理したことで形成された含ふっ素高分子化合物からなる。末端がイソシアネート官能基付き含ふっ素重合体を硬化処理したことで形成された含ふっ素高分子化合物は、−Ｃ_ＸＦ_２Ｘ−Ｏ−という一般式（Ｘは１〜４の整数）で示される単位を主要構造単位とし、いずれも平均分子量が数百万以上で硬化反応により分子間が結合した３次元の網状構造を有している。３次元の網状構造とは、化学構造上の表現であって、膜の断面が網状になっているのではなく、分子間が網状のように連続してつながって密に詰まった均質な構造になっていることを意味している。このような化合物としては、下記化学式４に示すような末端がイソシアネート官能基付き含ふっ素重合体を用いて、化学構造を変化させたものとすることができる。前述の末端がイソシアネート官能基付き含ふっ素重合体としては、パーフルオロポリエーテル（ＰＦＰＥ）の誘導体、具体的に例えばモンテカチーニ社の商品名フォンブリンＺ誘導体（FONBLIN Ｚ DISOCなど）が好適に用いられる。
【００３８】
【化４】

【００３９】
次に、上述した潤滑膜５の形成方法の一例を説明する。
【００４０】
（ａ） 固体状の潤滑膜５を得るための溶液を用意し、この溶液を用いて転がり軸受Ａの任意の必要部位に液状膜を付着させる（付着処理）。ここで用意する溶液は、末端がイソシアネートの官能基付き含ふっ素重合体〔フォンブリンＺ誘導体（FONBLIN Z DISOC）〕を希釈溶媒（ふっ素系溶剤ＳＶ９０Ｄ）で含ふっ素重合体の濃度を１ｍａｓｓ％にまで希釈したものである。
【００４１】
（ｂ） 液状膜を付着した対象のみあるいは転がり軸受Ａの全体を４０〜５０℃で約１分間加熱し、液状膜に含む溶媒を除去する（乾燥処理）。この時点では、液状膜のままであり、流動性を有している。
【００４２】
（ｃ） この後、例えば１００〜２００℃で２０時間、加熱する（硬化処理）。これにより、液状膜の化学構造が変化することにより硬化反応して固体状の潤滑膜５が得られる。ちなみに、この硬化処理では、液状膜に存在している官能基付き含ふっ素重合体の個々について、下記化学式５〜８に示すような４種の硬化反応でもって末端のイソシアネート（NCO）が消失し、各官能基付き含ふっ素重合体が互いに結合することにより３次元の網状構造となる。結合は、化学式５，６に示すような硬化反応でもって、図３（ａ）に模式的に示すように直線的に架橋するとともに、化学式７，８に示すような硬化反応でもって、図３（ｂ）に模式的に示すように３次元方向で架橋する。なお、図３では、下記化学式９に示すように、上記化学式４を簡略化して模式的に表している。
【００４３】
【化５】

【００４４】
【化６】

【００４５】
【化７】

【００４６】
【化８】

【００４７】
【化９】

【００４８】
このようにすれば、転がり軸受Ａの必要部位に固体状の潤滑膜５を好適な膜厚で形成することができる。なお、（ａ）、（ｂ）は必要に応じて数回繰り返すようにしてもよく、最終的には、潤滑膜５の膜厚を例えば０．２μｍ以下に適宜設定する。
【００４９】
ここで、（ａ）で用意した溶液を濃縮乾燥しただけの状態（流動性がある状態）と、（ａ）で用意した溶液をステンレス鋼板などの試料に付着して硬化した状態とについて、その性状を分析したので説明する。
【００５０】
前者は、ＦＴ−ＩＲ法（フーリエ変換−赤外分光、液膜法）で分析している。その結果は、図４のグラフに示すように、ふっ素系のピーク以外にＮＨ（３３０ｃｍ^−１）、Ｎ＝Ｃ＝Ｏ（２２７９ｃｍ^−１）、ＮＨＣ＝Ｏ（１７１２ｃｍ^−１，１５４６ｃｍ^−１）、ベンゼン（１６００ｃｍ^−１）などのピークが見られ、ベンゼン環、ＮＨＣ＝Ｏ結合、イソシアネートが官能基として存在していることが確認できる。ここでは、薄膜と厚膜との場合についてそれぞれ調べているが、膜厚に関係なく分析が行えた。後者は、ＦＴ−ＩＲ法（フーリエ変換−赤外分光、高感度反射法）で分析している。その結果は、図５のグラフに示すように、ベンゼン環やＮＨＣ＝Ｏ結合のピークが見られるが、イソシアネートのピークが見られない。つまり、これらの結果に基づき、上記化学式５〜８に示す硬化反応による官能基の化学構造変化が確認される。
【００５１】
以上説明した固体状の潤滑膜５は、それ自体が３次元の網状構造をもって、被覆対象上に緻密に被覆されるとともに自己潤滑性を有するため、上記実施例よりもさらに一層長期にわたって優れた回転特性を発揮できるようになる。この他、固体状であるから、衝撃荷重に対し若干ながらも緩衝作用を発揮するので、耐衝撃性に優れるものとなる。
【００５２】
この実施例において、上記（ｃ）の硬化処理については、加熱に代えて、紫外線、赤外線、γ線、電子線などの電磁波（光）のエネルギーを利用することができる。また、（ｂ）の乾燥処理は、省略してもよい。
【００５３】
この固体状の潤滑膜５の場合、末端がイソシアネート官能基付き含ふっ素重合体を硬化処理したことで形成された含ふっ素高分子化合物中に、フルオロポリエーテルなどの末端がイソシアネート官能基付き含ふっ素重合体と結合しない含ふっ素重合体を流動可能に分散添加した構造とすることもできる。この場合、具体的に、上記形成方法の（ａ）の付着処理において、用意する溶液を、末端がイソシアネートの官能基付き含ふっ素重合体〔例えば商品名フォンブリンＺ誘導体（FONBLIN Ｚ DISOCなど）〕と、含ふっ素重合体として官能基なし含ふっ素重合体〔例えば商品名フォンブリンＺ誘導体（FONBLIN Ｚ−６０など）〕とを所定の割合で混合したものとすればよい。この場合では、（ｃ）の硬化処理において、官能基なし含ふっ素重合体が、官能基付き含ふっ素重合体と結合しないので、これが、固体状の潤滑膜５の内部において流動可能となり、膜表面から滲み出るなどして潤滑作用を発揮することになる。
【００５７】
【発明の効果】
本発明の転がり軸受では、少なくとも保持器と軌道輪とが摺接する可能性のある部位に発塵性および潤滑性に優れた潤滑膜を形成しているから、たとえ軸受内部の潤滑剤が枯渇しても、前記摺接部位の早期摩耗を防止でき、ひいては軸受の破損を未然に防止できる。
【００５８】
しかも、潤滑剤の枯渇状態での使用時間が経過するに従い、トルク増加が起こって回転速度が低下し、回転速度の低下に伴い発生する音が変化することになるが、この変化によって潤滑剤の供給忘れを作業者に気付かせることが可能となる。このとき、潤滑膜によって軸受構成要素を保護しているので、ほとんど損傷せずに済むし、後で潤滑剤を供給したとき、通常どおりに動作させて再使用できるようになる。
【００５９】
また、潤滑膜を末端がイソシアネート官能基付き含ふっ素重合体を硬化処理したことで形成された含ふっ素高分子化合物からなる固体状とする場合には、分子間が密に詰まった均質な構造であるので、潤滑作用が長期的に継続できるようになる。しかも、この固体状の潤滑膜に末端がイソシアネート官能基付き含ふっ素重合体と結合しない含ふっ素重合体を流動可能な状態で分散添加しているため、この末端がイソシアネート官能基付き含ふっ素重合体と結合しない流動可能な含ふっ素重合体が膜表面から滲み出て潤滑作用に寄与するので、潤滑性の一層の向上に貢献できる。
【００６０】
したがって、例えば歯科用ハンドピースなどの高速回転で使用される場合において、潤滑剤の供給忘れがあっても、軸受の破損を回避できて、再度の潤滑剤供給によりそのまま継続して再使用できるようになるなど、うっかりミスに対する安全対策が万全となる。
【図面の簡単な説明】
【図１】本発明の一実施例にかかる転がり軸受の上半分の縦断面図
【図２】本発明の転がり軸受を用いた歯科用ハンドピースを示す断面図
【図３】固体状の潤滑膜の構造を模式的に表した構造図
【図４】固体状の潤滑膜の硬化前の状態での性状分析結果を示すグラフ
【図５】固体状の潤滑膜の硬化後の状態での性状分析結果を示すグラフ
【符号の説明】
Ａ 転がり軸受
１ 内輪
２ 外輪
３ 転動体
４ 保持器
５ 潤滑膜[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rolling bearing, and more particularly to a rolling bearing suitable for use in high-speed rotation applications such as dental handpieces and machine tools.
[0002]
[Prior art]
For example, in a dental handpiece, in order to reduce tooth discomfort in a short time and reduce patient discomfort, a rotating shaft with a grindstone at the tip is made as fast as possible (for example, 400,000 rpm). Driven by rotation, the peripheral speed of the grindstone is increased to improve the sharpness.
[0003]
In the above-mentioned dental handpiece that rotates at a high speed, generally, ceramic balls mainly made of silicon nitride, inner and outer rings made of stainless steel, and a crown made of a synthetic resin such as polyimide or polyamideimide are used. A deep groove type ball bearing having a combination of a shape cage and the like is used, and a user periodically supplies a lubricant. As this lubricant, for example, poly alpha olefin (PAO) or liquid paraffin such as ISO standard VG32, VG68, etc., which is not harmful to the human body, is used, and is supplied mixed with compressed air serving as a handpiece drive source.
[0004]
[Problems to be solved by the invention]
By the way, as described above, when the worker periodically supplies the lubricant, the supply may be forgotten due to a mistake.
[0005]
In such a case, the sliding motion of the cage and either the inner or outer ring that guides the cage is performed without lubrication. It will be caught between the ball and the inner / outer ring, causing a locking phenomenon that the rotation stops. When such a situation occurs, even if the lubricant is supplied after that, it is often impossible to use such as being unable to rotate. Therefore, it is necessary to replace the bearing.
[0006]
Therefore, an object of the present invention is to improve the lubricity of the sliding portion between the cage and the race and achieve a long life even when the lubricant is depleted in the rolling bearing.
[0007]
[Means for Solving the Problems]
The first rolling bearing of the present invention is a rolling bearing using grease or oil as a lubricant, and at least a polyfluoroalkyl polymer or an epoxy group on the raceway guide surface of the cage or the cage guide surface of the raceway ring , A lubricating film obtained by drying a fluoropolymer having a functional group selected from an amino group, a carboxyl group, a hydroxyl group, a mercapto group, a sulfone group or an ester group and a fluoropolymer that is a mixture of a perfluoropolyether. Is formed.
[0008]
A second rolling bearing according to the present invention is a rolling bearing using grease or oil as a lubricant, and at least the end of the rolling bearing with a isocyanate functional group on the raceway guide surface of the cage or the cage guide surface of the raceway. A solid lubricating film made of a fluorine-containing polymer compound formed by curing the coal is formed, and the solid lubricating film is flowable so that the terminal does not bind to the fluorine-containing polymer having an isocyanate functional group. A fluorine-containing polymer is added in a dispersed manner.
[0009]
The solid lubricant film described above has a three-dimensional network structure in which molecules are bonded . The solid lubricating film is dispersed and added with a flowable fluorine-containing polymer whose terminal does not bind to the fluorine-containing polymer with an isocyanate functional group . The flowable fluorine-containing polymer in which the terminal is not bonded to the fluorine-containing polymer with an isocyanate functional group is a non-functional group-containing fluorine- containing polymer such as a perfluoropolyether having no functional group. preferable.
[0010]
In the present invention, even when the supply of the lubricant is forgotten and the lubricant in the bearing is depleted, the cage and the race are brought into sliding contact via the lubricant film. This lubricating film is remarkably superior in terms of dust generation and lubricity and does not cause film breakage, so that direct contact between the cage and the raceway ring is prevented.
[0011]
As the usage time in such a depleted state of lubricant elapses, torque increases and the rotational speed decreases and the generated sound changes.This change causes the operator to forget to supply the lubricant. It becomes possible to notice. At this time, since the bearing component is protected by the lubricating film, seizure does not occur, and when the lubricant is supplied later, it can be operated and reused as usual.
[0012]
In addition, when the lubricating film is made into a solid state composed of a fluorine-containing polymer compound formed by curing a fluorine-containing polymer having an isocyanate functional group at the end, it has a homogeneous structure with tightly packed molecules. As a result, the lubricating action can be continued for a long time. Moreover, this solid for lubrication film ends are dispersed added flowable state fluorine-containing polymer which does not bind with the isocyanate functional group-containing fluorine polymer, the terminal isocyanate functional groups with a fluorine-containing polymer A flowable fluorine-containing polymer that does not bind to the water oozes out from the film surface and contributes to the lubricating action.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The details of the present invention will be described based on the embodiment shown in FIGS.
[0014]
1 and 2 relate to one embodiment of the present invention, FIG. 1 is a longitudinal sectional view of an upper half of a rolling bearing, and FIG. 2 is a sectional view showing a dental handpiece.
[0015]
First, referring to FIG. 2, the configuration of the dental handpiece will be briefly described. The dental handpiece 50 includes a housing 51, a rotating shaft 52 that is disposed in the housing 51 with one end projecting outside, a turbine blade 53 that is fixed to a middle portion of the rotating shaft 52, and a turbine blade 53. Rolling bearings A that rotatably support the rotary shaft 52 on the housing 51 on both sides of the turbine blade 53. By supplying compressed air into the housing 51, the turbine blades 53 and the rotary shaft 52 are rotated at high speed. The compressed air is mixed with, for example, poly alpha olefin (PAO) such as LipoLube 60 manufactured by Lion Co., which has no harm to the human body, and passes through the inside of the rolling bearing A in a mist form for lubrication and cooling. Do.
[0016]
As shown in FIG. 1, the rolling bearing A is called a deep groove type ball bearing, and includes an inner ring 1, an outer ring 2, a spherical rolling element 3, and a crown-shaped cage 4. In this rolling bearing A, the following lubricating film 5 is formed on the rolling and sliding portions of the inner and outer rings 1 and 2, the rolling elements 3 and the cage 4.
[0017]
The inner / outer rings 1 and 2 are made of a corrosion-resistant material. Examples of the corrosion resistant material include a metal material obtained by subjecting a martensitic stainless steel such as JIS standard SUS440C to a suitable hardening heat treatment to a precipitation hardening type stainless steel such as JIS standard SUS630. In light load applications, for example, austenitic stainless steel such as JIS standard SUS304 may be used.
[0018]
The rolling element 3 is formed of a ceramic material. As the ceramic material, yttria (Y ₂ O ₃ ) and alumina (Al ₂ O ₃ ) are used as sintering aids, and aluminum nitride (AlN), titanium oxide (TiO ₂ ), spinel (MgAl ₂ O), as appropriate. ₄ ) In addition to silicon nitride (Si ₃ N ₄ ) mainly used, alumina (Al ₂ O ₃ ), silicon carbide (SiC), zirconia (ZrO ₂ ), aluminum nitride (AlN), etc. are used. be able to.
[0019]
The cage 4 is made of a synthetic resin material. Examples of the synthetic resin material include thermoplastic resins having heat resistance, such as TPI (thermoplastic polyimide) resin filled with 5 to 10 wt% PTFE (polytetrafluoroethylene) and 10 to 20 wt% graphite, Fluorine resins such as tetrafluoroethylene (hereinafter abbreviated as PTFE), ethylenetetrafluoroethylene (ETFE), polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polyether sulfone (PES), polyether nitrile (PEN), polyamideimide (PAI), engineering plastics such as nylon 46, and the like. Reinforcing fibers such as glass fibers may be appropriately added to these resins. When not added, the strength decreases, but it is possible to avoid the exposed fibers from being worn on the pocket surface and biting into the raceway surface.
[0020]
The lubricating film 5 is made of, for example, a fluorine-containing polymer with a functional group. In this embodiment, the lubricating film 5 is in a fluid state. As this fluorine-containing polymer with a functional group, a fluoropolyether polymer or a polyfluoroalkyl polymer is preferable. The fluoropolyether polymer includes a unit represented by a general formula -C _X F _2X -O- (where X is an integer of 1 to 4) as a main structural unit, and each of the polymers has a number average molecular weight of 1000 to 50000 To do. Examples of the polyfluoroalkyl polymer include those represented by the following chemical formula 1. In addition, the functional group described above preferably has a high affinity for metals (for example, an epoxy group, an amino group, a carboxyl group, a hydroxyl group, a mercapto group, a sulfone group, or an ester group). What is shown. Such fluorine-containing polymers may be used alone or in combination of two or more. In that case, it is desirable to consider that the combined groups react with each other to increase the molecular weight of the polymer so that a film with more excellent wear resistance can be obtained.
[0021]
[Chemical 1]

[0022]
[Chemical formula 2]

[0023]
[Chemical 3]

[0024]
As the above-mentioned fluorine-containing polymer having a functional group, more specifically, a mixture with perfluoropolyether (PFPE) or a derivative thereof, specifically, for example, a trade name of Fonbrin (FONBLIN) standard of Montecatini, Fonbrin emulsion (FE20, EM04, etc.) or Fomblin Z derivatives (FONBLIN Z DEAL, FONBLIN Z DIAC, FONBLIN Z DISOC, FONBLIN Z DOL, FONBLIN Z DOLTX2000, FONBLIN Z TETRAOL, etc.) are preferably used. All of these exemplified substances have a high concentration and extremely low affinity for metals, so that it is difficult to attach them as they are. Therefore, it is preferable to form by the following method.
[0025]
Next, an example of a method for forming the lubricating film 5 described above will be described.
[0026]
(A) After the inner / outer rings 1 and 2, the rolling elements 3 and the cage 4 are assembled to complete the rolling bearing A, the rolling elements 3 are prepared between the inner and outer rings 1 and 2. By injecting a few drops of the solution with a spoid or the like and rotating it several times, the inner and outer rings 1 and 2 and the cage 4 roll, and the liquid film adheres to the sliding part and the surface of the rolling element 3 (attachment) processing). This solution can be attached using a spray or may be immersed in the solution. The solution prepared here is, for example, a fomblin emulsion FE20 (fomblin concentration 20 mass%) diluted with an appropriate diluent solvent to a fomblin concentration of 0.25 mass%. In addition, the above-mentioned dilution solvent can be volatile, such as a methanol solution, an alcohol solution, or water.
[0027]
(B) The entire rolling bearing A to which the liquid film is attached is heated at 40 to 50 degrees for about 3 minutes to remove the solvent contained in the liquid film (drying process).
[0028]
(C) Thereafter, in consideration of the ambient temperature in the environment where the bearing is used, for example, heating is performed at 150 to 300 degrees for 15 to 30 minutes (finish drying process). For example, in the dental handpiece 50, for example, sterilization processing (autoclave processing) is performed with high-temperature steam at 135 ° C. to 180 ° C. or higher, and this temperature may be taken into consideration. Thereby, the lubricating film 5 having fluidity free from unnecessary dust generation such as a solvent and an oil component during the operation of the rolling bearing A or the sterilization process described above can be obtained.
[0029]
In this way, the lubricating film 5 can be formed with a suitable film thickness on the rolling and sliding portions of the components of the rolling bearing A. Note that (a) and (b) may be repeated several times as necessary. Finally, the thickness of the lubricating film 5 is set to 0.2 μm or less, for example. However, the properties of the lubricating oil used, the film forming method, the film thickness after generation, etc. may be set appropriately.
[0030]
In the rolling bearing A described above, the lubricating film 5 that is remarkably superior in terms of dust generation and lubricity is formed. Therefore, when the lubricant in the bearing is exhausted due to forgetting to supply the lubricant to the rolling bearing A or the like. However, since the retainer 4 and the inner ring 1 or the outer ring 2 are in sliding contact with each other through the lubricating film 5 and their direct contact is prevented, the sliding contact portion is hardly worn at an early stage. Moreover, as the usage time in such a lubricant depletion state elapses, the torque increases and the rotational speed decreases and the generated sound changes. It becomes possible to make the person aware. At this time, since the bearing component is protected by the lubricating film 5, it is possible to prevent seizure, and when the lubricant is supplied later, it can be operated and reused as usual.
[0031]
In addition, this invention is not limited only to the said Example, Various application and deformation | transformation can be considered.
[0032]
(1) Although the deep groove type ball bearing is cited as the bearing type in the above embodiment, the present invention can be applied to other types of rolling bearings.
[0033]
(2) In the above embodiment, the lubricating film 5 is formed on all of the inner and outer rings 1 and 2, the rolling elements 3 and the cage 4, but at least only on the inner and outer rings 1 and 2 or only on the cage 4. Can be formed.
[0034]
(3) In the above embodiment, the lubricating film 5 is formed on the outer peripheral surface of the inner ring 1, the inner peripheral surface of the outer ring 2, and the entire surfaces of the rolling elements 3 and the cage 4. You may form also on the whole surface of 2. In this case, for example, the inner and outer rings 1, 2, the rolling elements 3 and the cage 4 are individually immersed in the solution prepared in the process (a), or the completed bearing A in which they are assembled is immersed. do it. Further, the lubricating film 5 is formed on the corresponding surface (for example, the outer peripheral surface excluding the track of the inner ring 1 in the case of the inner ring guide, the inner surface excluding the track of the outer ring 2 in the case of the outer ring guide, depending on the guide type of the cage 4 It may be formed only on the peripheral surface. Furthermore, the lubricating film 5 may be formed only on the guide surface of the cage 4 (inner peripheral surface in the case of inner ring guide, outer peripheral surface in the case of outer ring guide).
[0035]
(4) In the above embodiment, the rolling bearing A is illustrated as an open type that does not have a sealing device. However, the rolling bearing A may be equipped with a sealing device.
[0036]
(5) In the above embodiment, the lubricating film 5 having fluidity is shown, but the solid lubricating film 5 as described below is also included in the present invention. FIG. 3 is a structural diagram schematically showing the structure of the solid lubricating film, FIG. 4 is a graph showing the result of property analysis of the solid lubricating film before curing, and FIG. It is a graph which shows the property analysis result in the state after hardening of a lubricating film.
[0037]
The aforementioned solid lubricating film 5 is made of a fluorine-containing polymer compound formed by curing a fluorine-containing polymer having an isocyanate functional group at the end . The fluorine-containing polymer compound formed by curing a fluorine-containing polymer having an isocyanate functional group at the end is a unit represented by the general formula (X is an integer of 1 to 4): -C _X F _2X -O- Are the main structural units, each having an average molecular weight of several million or more and a three-dimensional network structure in which molecules are bonded by a curing reaction. The three-dimensional network structure is an expression in terms of chemical structure, and the cross-section of the film is not a network, but a homogeneous structure in which molecules are connected in a continuous manner like a network. It means that As such a compound, the chemical structure can be changed by using a fluorine-containing polymer having an isocyanate functional group at the end as shown in the following chemical formula 4. As the above-mentioned fluorine-containing polymer having an isocyanate functional group, a derivative of perfluoropolyether (PFPE), specifically, for example, a trade name fomblin Z derivative (FONBLIN Z DISOC etc.) of Montecatini is preferably used.
[0038]
[Formula 4]

[0039]
Next, an example of a method for forming the lubricating film 5 described above will be described.
[0040]
(A) A solution for obtaining the solid lubricating film 5 is prepared, and a liquid film is attached to any necessary portion of the rolling bearing A using this solution (attachment treatment). The solution prepared here is a fluorine-containing polymer having a functional group whose end is isocyanate [FONBLIN Z DISOC], and the concentration of the fluorine-containing polymer is reduced to 1 mass% with a diluting solvent (fluorine solvent SV90D). Diluted.
[0041]
(B) Only the object to which the liquid film is adhered or the entire rolling bearing A is heated at 40 to 50 ° C. for about 1 minute to remove the solvent contained in the liquid film (drying process). At this time, it remains a liquid film and has fluidity.
[0042]
(C) Then, it heats, for example at 100-200 degreeC for 20 hours (curing process). As a result, the solid lubricating film 5 is obtained through a curing reaction due to a change in the chemical structure of the liquid film. By the way, in this curing treatment, the terminal isocyanate (NCO) disappears in each of the fluorine-containing polymers with functional groups present in the liquid film by four curing reactions as shown in the following chemical formulas 5-8. , each functional group with fluorine-containing polymer is a three-dimensional network structure by binding to each other. Bonding is performed by a curing reaction as shown in Chemical Formulas 5 and 6, linearly cross-linking as schematically shown in FIG. 3A, and by a curing reaction as shown in Chemical Formulas 7 and 8, as shown in FIG. As schematically shown in (b), crosslinking is performed in a three-dimensional direction. In addition, in FIG. 3, as shown in the following chemical formula 9, the chemical formula 4 is simplified and schematically shown.
[0043]
[Chemical formula 5]

[0044]
[Chemical 6]

[0045]
[Chemical 7]

[0046]
[Chemical 8]

[0047]
[Chemical 9]

[0048]
In this way, the solid lubricating film 5 can be formed at a suitable thickness on the necessary portion of the rolling bearing A. Note that (a) and (b) may be repeated several times as necessary. Finally, the thickness of the lubricating film 5 is appropriately set to 0.2 μm or less, for example.
[0049]
Here, the state prepared by concentrating and drying the solution prepared in (a) (the state having fluidity) and the state prepared by attaching the solution prepared in (a) to a sample such as a stainless steel plate and curing the I will explain the properties.
[0050]
The former is analyzed by the FT-IR method (Fourier transform-infrared spectroscopy, liquid film method). As shown in the graph of FIG. 4, NH (330 cm ⁻¹ ), N═C═O (2279 cm ⁻¹ ), NHC ═O (1712 cm ⁻¹ , 1546 cm ⁻¹ ), Peaks such as benzene (1600 cm ⁻¹ ) are observed, and it can be confirmed that a benzene ring, NHC═O bond, and isocyanate are present as functional groups. Here, the cases of the thin film and the thick film are examined, but the analysis can be performed regardless of the film thickness. The latter is analyzed by the FT-IR method (Fourier transform-infrared spectroscopy, high sensitivity reflection method). As a result, as shown in the graph of FIG. 5, the peak of the benzene ring and NHC═O bond is seen, but the peak of isocyanate is not seen. That is, based on these results, the chemical structure change of the functional group due to the curing reaction shown in the above chemical formulas 5 to 8 is confirmed.
[0051]
The solid lubricating film 5 described above itself has a three-dimensional network structure, is densely coated on the object to be coated, and has a self-lubricating property. It becomes possible to demonstrate the characteristics. In addition, since it is in a solid state, it exhibits a buffering action with a slight impact load, and therefore has excellent impact resistance.
[0052]
In this embodiment, for the curing process (c), energy of electromagnetic waves (light) such as ultraviolet rays, infrared rays, γ rays, and electron beams can be used instead of heating. Further, the drying process (b) may be omitted.
[0053]
In the case of this solid lubricating film 5, a fluorine-containing polymer compound formed by curing a fluorine-containing polymer having an isocyanate functional group at the terminal is used to form a fluorine-containing polymer having an isocyanate functional group at the terminal such as fluoropolyether. the fluorine-containing polymer that does not bind to the polymer may also be a flowable dispersed the added structure. In this case, specifically, in the adhesion treatment of (a) in the above formation method, the prepared solution is a fluorine-containing polymer having an isocyanate-terminated functional group (for example, a trade name fomblin Z derivative (FONBLIN Z DISOC, etc.)). And a fluorine-containing polymer having no functional group (for example, a trade name Fomblin Z derivative (FONBLIN Z-60, etc.)) as a fluorine-containing polymer may be mixed at a predetermined ratio. In this case, in the curing process (c), the fluorine-containing polymer having no functional group is not bonded to the fluorine-containing polymer having a functional group, so that it can flow inside the solid lubricating film 5, and the film surface The oil will exude from the surface and exert a lubricating effect .
[0057]
【The invention's effect】
In the rolling bearing of the present invention, since the lubricating film having excellent dust generation and lubricity is formed at least at the portion where the cage and the raceway may come into sliding contact, the lubricant inside the bearing is depleted. However, premature wear of the sliding contact portion can be prevented, and as a result, damage to the bearing can be prevented.
[0058]
In addition, as the usage time in the depleted state of the lubricant elapses, the torque increases and the rotational speed decreases, and the sound generated as the rotational speed decreases changes. It becomes possible to make the operator notice that the supply has been forgotten. At this time, since the bearing component is protected by the lubricating film, it is hardly damaged, and when the lubricant is supplied later, it can be operated and reused as usual.
[0059]
In addition, when the lubricating film is made into a solid state composed of a fluorine-containing polymer compound formed by curing a fluorine-containing polymer having an isocyanate functional group at the end, it has a homogeneous structure with tightly packed molecules. As a result, the lubricating action can be continued for a long time. Moreover, this solid for lubrication film ends are dispersed added flowable state fluorine-containing polymer which does not bind with the isocyanate functional group-containing fluorine polymer, the terminal isocyanate functional groups with a fluorine-containing polymer Since the flowable fluorine-containing polymer that does not bind to the fluid oozes out from the film surface and contributes to the lubricating action, it can contribute to further improvement in lubricity.
[0060]
Therefore, for example, when the dental handpiece is used at high-speed rotation, even if the supply of the lubricant is forgotten, the bearing can be prevented from being damaged and can be continuously reused by supplying the lubricant again. Safety measures against accidental mistakes will be perfect.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an upper half of a rolling bearing according to an embodiment of the present invention. FIG. 2 is a sectional view showing a dental handpiece using the rolling bearing of the present invention. Fig. 4 is a graph showing the result of property analysis of a solid lubricant film before curing. Fig. 5 is a property analysis of a solid lubricant film after curing. Graph showing results 【Explanation of symbols】
A Rolling bearing 1 Inner ring 2 Outer ring 3 Rolling element 4 Cage 5 Lubrication film

Claims (4)

Rolling bearings using grease or oil as a lubricant, at least on the raceway guide surface of the cage or the cage guide surface of the raceway, a polyfluoroalkyl polymer or epoxy group, amino group, carboxyl group, hydroxyl group, mercapto group A lubricating film is formed by drying a fluorine-containing polymer that is a mixture of a fluoropolyether polymer with a functional group selected from a sulfone group or an ester group and a perfluoropolyether. Rolling bearing. Rolling bearing using grease or oil as a lubricant, and formed by curing a fluorine-containing polymer having an isocyanate functional group at least on a raceway guide surface of a cage or a cage guide surface of a raceway ring A solid lubricating film made of a fluorine-containing polymer compound is formed, and the solid lubricating film is dispersed and added with a flowable fluorine-containing polymer that does not bond to the fluorine-containing polymer with an isocyanate functional group at the end. A rolling bearing characterized by that. The rolling bearing according to claim 2, wherein the flowable fluorine-containing polymer does not have a functional group.   The rolling bearing according to claim 2, wherein the solid lubricating film has a three-dimensional network structure in which molecules are bonded.

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