JP4305453B2 - Rolling and sliding parts - Google Patents

Description

  The present invention relates to a rolling / sliding component in which rolling contact or sliding contact occurs relatively with a mating member. Examples of the rolling sliding component include components such as a rolling bearing, a ball screw, and a direct acting bearing.

  Conventionally, a soft metal such as gold, silver, lead, or copper, or a solid lubricant such as carbon or molybdenum disulfide has been coated on the contact surface of a rolling sliding component in a film shape.

  By the way, the above-described film is said to have a large amount of dust generation and low load resistance. On the other hand, a film made of polytetrafluoroethylene resin (abbreviation: PTFE) is used as one having a small dust generation amount and high load resistance. This film is formed in a solid state.

  In addition, the applicant of the present application has proposed a lubricating film made of a fluorine-containing polymer with a functional group, which exhibits better dust generation and lubricity than the aforementioned film. The lubricating film can be in a liquid state having fluidity or a solid state having a high molecular weight. However, it is pointed out that such a lubricating film is softer than the above-described PTFE and inferior in load resistance when made into a solid state. In addition, when it is in a liquid state, although it is excellent in load resistance compared with a solid state, it is slightly inferior compared with the above-mentioned PTFE.

  Accordingly, an object of the present invention is to improve particularly the load resistance of the contact surface of the rolling sliding part.

The first rolling / sliding part of the present invention is a rolling / sliding part in which a relative contact or sliding contact occurs with a mating member, and a solid film is formed on a contact surface of the rolling / sliding part with the mating member. The solid film comprises a compound represented by the following chemical formula 21, a flowable fluorine-containing polymer that does not bind to the fluorine-containing polymer having an isocyanate functional group, and particles made of polytetrafluoroethylene resin. And at least any one of the following chemical formulas 31 and 32, and 33 and 34 are provided by crosslinking with a curing reaction of any one of the following chemical formulas 41 and 42 and 43 and 44, Particles made of polytetrafluoroethylene resin and flowable without bonding to fluorine-containing polymer with isocyanate functional group at the end A fluorine-containing polymer, Ri solid film der dispersed is, the flowable fluorine-containing polymer has no functional group.

The second rolling / sliding component of the present invention is a rolling / sliding component in which a relative contact or sliding contact occurs with a mating member, and a solid film is formed on the contact surface of the rolling / sliding component with the mating member. The solid film has a bond of any one of the following chemical formulas 31 and 32, 33 and 34, and has a unit represented by the following chemical formula 51 as a main structural unit, has a particle comprising ethylene resins, end the fluorine-containing polymer flowable without being combined with a fluorine-containing conditioned isocyanate functional groups, solid film der dispersed is is, the flowable fluorine-containing polymer is a functional group Not.

The third rolling / sliding part of the present invention is a rolling / sliding part in which a relative contact or sliding contact occurs with a mating member, and a solid film is formed on the contact surface of the rolling / sliding part with the mating member. The solid film comprises a compound represented by the following chemical formula 21, a flowable fluorine-containing polymer that does not bind to the fluorine-containing polymer having an isocyanate functional group, and particles made of polytetrafluoroethylene resin. Are mixed by at least the curing reaction of any one of the following chemical formulas 41, 42, 43, and 44 to provide at least a bond of the following chemical formulas 31 and 32, 33, and 34, and the following chemical formula: A solid film having a unit represented by 51 as a main structural unit, the particles comprising the polytetrafluoroethylene resin, and the powder There a flowable fluorine-containing polymer which does not bind with the isocyanate functional group with fluorine-containing polymers, Ri solid film der dispersed is, the flowable fluorine-containing polymer has no functional group.

In the first to third inventions of the present invention, the solid lubricating film preferably has a three-dimensional network structure in which molecules are bonded.

In the first to third aspects of the present invention, the particles are preferably spherical.

In the first to third inventions of the present invention, it is preferable that the film thickness is set to be close to the maximum particle diameter of the spherical particles.

  In the present invention, since the particles made of polytetrafluoroethylene resin are excellent not only in lubricity but also in load resistance, the load bearing capacity of the entire lubricating film is increased.

  Further, when the lubricating film is in a solid state, the lubrication action can be continued for a long time because of a homogeneous structure in which the molecules are closely packed. In addition, when the fluorine-containing polymer is dispersed and added to the solid lubricating film in a flowable state, the flowable fluorine-containing polymer oozes out from the film surface and contributes to the lubricating action.

  In the present invention, since a lubricating film excellent in dust generation, lubricity and load resistance is formed on the contact surface of the rolling sliding part, wear due to rolling and sliding operation under a high load condition Can be extended over a long period of time.

  In addition, when the lubricating film is in a solid state, the lubricating action can be continued for a long time because the structure is a homogeneous structure in which the molecules are closely packed. In addition, in the case where the fluorine-containing polymer is dispersed and added to the solid lubricating film in a flowable state, the flowable fluorine-containing polymer oozes out from the film surface and contributes to the lubricating action. It can contribute to further improvement of sex.

  The details of the present invention will be described based on the embodiment shown in FIGS.

  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 an enlarged sectional view schematically showing a lubricating film. Here, a rolling bearing is illustrated as a rolling sliding part.

  In the figure, A indicates the entire rolling bearing called a deep groove type ball bearing, wherein 1 is an inner ring, 2 is an outer ring, 3 is a spherical rolling element, 4 is a crown-shaped cage, and 5 is a lubricating film. In the illustrated example, the rolling bearing A is an open type having no sealing device.

  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.

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.

  The cage 4 is made of low carbon steel such as synthetic resin material or SPCC material, stainless steel such as SUS304, or the like. Synthetic resin materials include thermoplastic resins having heat resistance, for example, 5-10 wt% polytetrafluoroethylene resin (PTFE) and thermoplastic polyimide resin (TPI) filled with 10-20 wt% graphite, Fluorine resins such as tetrafluoroethylene (PTFE) and ethylenetetrafluoroethylene (ETFE), polyether ether ketone (PEEK), polyphenylene sulfide (PPS), polyether sulfone (PES), polyether nitrile (PEN), polyamide Examples thereof include engineering plastics such as imide (PAI) and nylon 46. 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.

  In the rolling bearing A, a lubricating film 5 described below is formed on the entire surfaces of the inner and outer rings 1 and 2, the rolling elements 3 and the cage 4.

As shown in FIG. 2, the lubricating film 5 is made of a fluorine-containing polymer with a functional group in which particles 6 made of, for example, polytetrafluoroethylene resin (PTFE) are dispersed and mixed, and has a fluid state. As the fluorine-containing polymer having 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. Furthermore, it is desirable that the PTFE to be the particles 6 is spherical, and, for example, the trade name Celarub V manufactured by Central Glass Co., Ltd. is preferably used.

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. Next, an example of a method for forming the lubricating film 5 described above will be described.

 (A) A solution for obtaining the lubricating film 5 is prepared, and the inner / outer rings 1, 2, the rolling element 3 and the cage 4 are individually immersed in the solution, or they are assembled to obtain a completed state. By immersing the rolling bearing A and rotating it several times, a liquid film is adhered to the entire surfaces of the inner and outer rings 1, 2, the rolling element 3 and the cage 4 (attachment treatment). This solution can also be deposited using a spray. The solution prepared here is, for example, fomblin emulsion FE20 (fomblin concentration 20 mass%) diluted with an appropriate diluent solvent to a fomblin concentration of 0.25 mass%, and the particle size is about 1 to 2 μm. For example, 1 to 10 wt% of spherical particles 6 are dispersed and mixed. The diluting solvent described above can be a volatile solvent such as a methanol solution, an alcohol solution or water, or a fluorine-based solvent SV90D as an alternative chlorofluorocarbon.

 (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).

 (C) Thereafter, in consideration of the atmospheric temperature in the bearing use environment, for example, heating is performed at 100 to 200 ° C. for 15 to 30 minutes (finish drying treatment). Thereby, the lubricating film 5 having fluidity free from unnecessary dust generation such as solvent and oil component during operation of the rolling bearing A is obtained.

  In this way, the lubricating film 5 can be formed with a suitable film thickness on the components of the rolling bearing A. Note that (a) and (b) may be repeated several times as necessary. Finally, the film thickness of the lubricating film 5 is approximated to the maximum particle diameter of the particles 6, for example, about 1 to 2 μm. Set to. As shown in FIG. 2, the lubricating film 5 formed in this way is in a state where the upper part of the particle 6 is not exposed and a part of the lubricating film 5 is interposed below the particle 6. Specifically, the surface is almost flat. The particles 6 are set so as to account for 25 to 50% of the total area of the lubricating film 5. If it is less than 25% of the lower limit, there is not much effect on the load resistance, and if it exceeds 50% of the upper limit, the lubricating properties of the fluorine-containing polymer are deteriorated and the particles 6 are peeled off to become a dust generation source.

The rolling bearing A described above includes rolling and sliding parts between the inner / outer rings 1 and 2 and the rolling element 3, sliding parts between the cage 4 and the inner ring 1 or the outer ring 2, and rolling elements 3 and the cage 4. The contact portion becomes a contact with the lubricating film 5 interposed therebetween, and the bearing components do not directly contact each other. In addition, since the lubricating film 5 itself has very little wear and dust generation due to rolling and sliding operations, it is possible to avoid direct contact between the bearing components over a long period of time so that a long life can be achieved. Become. Moreover, since the buffering action against the load is increased by the particles 6 in the lubricating film 5, the load resistance is improved. Incidentally, regarding the load resistance, in the case of the lubricating film 5 in which the particles 6 are not mixed, the upper limit value of the load bearing capacity is about 150 kgf / mm ² , whereas in the case of the lubricating film 5 in which the particles 6 are mixed. Then, it improves to 200 kgf / mm ² . In particular, when the particles 6 are spherical, the load distribution is widened, and a large buffering effect can be obtained. Furthermore, in the embodiment, since the lubricating film 5 is formed on the entire surface of the bearing component, the corrosion prevention effect is enhanced when used in a corrosion resistant environment, and it is not necessary to perform a separate corrosion prevention treatment.

  By the way, the present invention is not limited to the above embodiments, and various applications and modifications can be considered.

 (1) In the above embodiment, the rolling bearing A such as a deep groove type ball bearing is cited as the rolling sliding part, but the type of the rolling bearing is not particularly limited. Further, as the rolling / sliding parts, the present invention can be applied to rolling / sliding parts such as ball screws and linear motion bearings, and to other rolling / sliding parts such as various other mechanical parts.

 (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 only on the inner and outer rings 1 and 2 or only on the rolling elements 3. can do.

 (3) In the above embodiment, the lubricating film 5 is formed on the entire surfaces of the inner and outer rings 1 and 2, the rolling elements 3 and the cage 4, but for example, as shown in FIG. The lubricating film 5 may be formed on the inner peripheral surface of the outer ring 2, the rolling element 3, and the inner surface of the cage 4 (contact portion with the rolling element 3). In addition, in FIG. 3, the type which incorporated the sealing device is shown. That is, for the inner and outer rings 1 and 2, the raceway surface and the cage guide surface (for example, the outer peripheral surface of the shoulder of the inner ring 1 in the case of the inner ring guide, Further, the cage 4 may be formed on the inner surface or a guide surface (for example, an inner peripheral surface in the case of an inner ring guide and an outer peripheral surface in the case of an outer ring guide). In this case, after the rolling bearing A is completed, a few drops of the prepared solution are injected between the inner and outer rings 1 and 2 with a spoid, etc., and are attached by rotating several times, or unnecessary portions are masked. In addition, before assembling as a bearing, it is conceivable that each single body is adhered by being immersed in the solution prepared in the above (a).

 (4) In the above embodiment, the lubricating film 5 having fluidity is illustrated, but the solid lubricating film 5 as described below is also included in the present invention. FIG. 4 is a structural diagram schematically showing the structure of the solid lubricating film, FIG. 5 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.

The solid lubricant film 5 is made of a fluorine-containing polyurethane polymer compound in which particles 6 made of polytetrafluoroethylene resin are dispersed and mixed. The particles 6 are the same as those described above. The fluorine-containing polyurethane polymer compound has a unit represented by the general formula -C _X F _2X -O- (X is an integer of 1 to 4) as a main structural unit, and all have an average molecular weight of several millions or more. It has a three-dimensional network structure in which molecules are bonded together. 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 with 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-terminated functional group, a derivative of perfluoropolyether (PFPE), specifically, for example, a product name Fomblin Z derivative (FONBLIN Z DISOC, etc.) of Montecatini is preferably used. .

  Next, an example of a method for forming the above-described solid lubricating film 5 will be described.

(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). It is assumed that spherical particles 6 having a diameter of about 1 to 2 μm are dispersed and mixed in, for example, 2 wt% with respect to the diluted one.

 (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.

 (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 functional fluorine-containing polymers present in the liquid film by four curing reactions as shown in the following chemical formulas 5-8. When the fluorine-containing polymers with functional groups are bonded to each other, a three-dimensional network structure is formed. Bonding is performed by a curing reaction as shown in Chemical Formulas 5 and 6, linearly cross-linking as schematically shown in FIG. 4A, 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. 4, as shown in the following chemical formula 9, the above chemical formula 4 is simplified and schematically shown.

  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, and finally the film thickness of the lubricating film 5 is appropriately set within a range of 1 to 2 μm, for example, depending on the application. can do.

  The solid lubricating film 5 thus obtained has a film thickness approximate to the diameter of the particle 6 as shown in FIG. Is not exposed, and a part of the lubricating film 5 is interposed below the particles 6, so that the surface is almost flat as a whole. The solid lubricating film 5 contains 3 wt% perfluoropolyether (PFPE) solid component, 0.75 wt% liquid component, and 2 wt% polytetrafluoroethylene resin (PTFE).

  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.

The former is analyzed by the FT-IR method (Fourier transform-infrared spectroscopy, liquid film method). As a result, as shown in the graph of FIG. 5, NH (3300cm ^-1) in addition to the peak of fluorine, N = C = O (2279cm -1), NHC = O (1712cm -1, 1546cm -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. 6, 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.

  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, the load resistance is the same as in the above embodiment. In addition, since the lubricating film 5 itself and the particles 6 are the same fluorine-based material, the familiarity is good and the particles 6 are difficult to peel off.

  In this embodiment, for the curing process (c), instead of heating, energy of electromagnetic waves (light) such as ultraviolet rays, infrared rays, γ rays, and electron beams can be used. Further, the drying process (b) may be omitted.

In the case of the solid lubricating film 5, a structure in which a fluorine-containing polymer such as fluoropolyether is dispersed and added to the fluorine-containing polyurethane polymer compound so as to be flowable can also be used. In this case, specifically, in the adhesion treatment of (a) in the above formation method, the prepared solution is a fluorine-containing polymer having a functional group having an isocyanate terminal (for example, a trade name fomblin Z derivative (FONBLIN Z DISOC, etc.)). And a fluorine-containing polymer having no functional group as a fluorine-containing compound [for example, trade name Fomblin Z derivative (FONBLIN Z-60, etc.)] 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. The fluorine-containing polymer is not limited to the above-mentioned fluorine-containing polymer having no functional group, and may be a fluorine-containing polymer with a functional group as shown in Chemical Formulas 10, 11, and 12.

The longitudinal cross-sectional view of the upper half of the rolling bearing concerning one Example of this invention Cross-sectional enlarged view schematically showing the lubricating film The longitudinal cross-sectional view of the upper half of the rolling bearing concerning the other Example of this invention Structure diagram schematically showing the structure of a solid lubricating film Graph showing the result of property analysis of solid lubricant film before curing The graph which shows the property analysis result in the state after hardening of a solid lubricating film

Explanation of symbols

A Rolling bearing 1 Inner ring 2 Outer ring 3 Rolling element 4 Cage 5 Lubricating film 6 Particles

Claims (6)

A rolling sliding part in which a relative contact or sliding contact occurs with a mating member,
A solid film is formed on the contact surface of the rolling sliding part with the mating member,
The solid film is
A mixture of a compound represented by the following chemical formula 21 and a flowable fluorine-containing polymer that does not bind to the fluorine-containing polymer having an isocyanate functional group and particles made of polytetrafluoroethylene resin at a predetermined ratio, By crosslinking by the curing reaction of any one of the following chemical formulas 41 and 42 and 43 and 44, at least a bond of any of the following chemical formulas 31 and 32 and 33 and 34 is provided,
Particles made of the polytetrafluoroethylene resin;
Said end and flowable fluorine-containing polymer which does not bind with the isocyanate functional group with fluorine-containing polymers, Ri solid film der dispersed is,
The flowable fluorine-containing polymer has no functional group ,
Rolling sliding parts characterized by that.

A rolling sliding part in which a relative contact or sliding contact occurs with a mating member,
A solid film is formed on the contact surface of the rolling sliding part with the mating member,
The solid film is
A solid film having any one of the following chemical formulas 31 and 32 and 33 and 34, and having a unit represented by the following chemical formula 51 as a main structural unit,
Particles made of polytetrafluoroethylene resin;
End and flowable fluorine-containing polymer that does not bind to a fluorine-containing conditioned isocyanate functional groups, Ri solid film der dispersed is,
The flowable fluorine-containing polymer has no functional group ,
Rolling sliding parts characterized by that.

A rolling sliding part in which a relative contact or sliding contact occurs with a mating member,
A solid film is formed on the contact surface of the rolling sliding part with the mating member,
The solid film is
A mixture of a compound represented by the following chemical formula 21 and a flowable fluorine-containing polymer that does not bind to the fluorine-containing polymer having an isocyanate functional group and particles made of polytetrafluoroethylene resin at a predetermined ratio, By crosslinking by the curing reaction of any one of the following chemical formulas 41, 42, 43, and 44, at least a bond of any one of the following chemical formulas 31 and 32, 33, and 34 is provided, and the unit represented by the following chemical formula 51 is the main structural unit. A solid film,
Particles made of the polytetrafluoroethylene resin;
Said end and flowable fluorine-containing polymer which does not bind with the isocyanate functional group with fluorine-containing polymers, Ri solid film der dispersed is,
The flowable fluorine-containing polymer has no functional group ,
Rolling sliding parts characterized by that.

The solid state of the lubricating film has a three-dimensional network structure between molecules is bound, rolling sliding part of claim 1 to 3. The particles are spherical, rolling slide member according to any one of claims 1 to 4. The rolling / sliding part according to claim 5 , wherein the lubricating film is set to a film thickness that approximates a maximum particle diameter of the spherical particles.

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