JP2010196801A - Retainer for ball bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retainer for a ball bearing, which reduces a shearing resistance of an oil film functioning between a pocket inner peripheral surface and a surface of a rolling element (ball), and at the same time maintains an effect due to a low torque constant during bearing rotation for a long period of time. <P>SOLUTION: The retainer 8 for the ball bearing revolves along the inside of a bearing along with a plurality of rolling elements while rotatably retaining the plurality of rolling elements in the inside of the bearing. The retainer is provided with: a retainer body 8a which has a plurality of pockets 8p rotatably retaining; the plurality of rolling elements one by one and a plurality of protuberances 8t which are formed by partially projecting internal surface Ps of each of the pockets, and also is provided with a water-repellent and oil-repellent film 8b on surface of the retainer body so as to cover at least the plurality of protuberances formed in the internal surface of each of the pockets. In this case, the water-repellent and oil-repellent film is configured to form a metal oxide layer on the surface of the retainer body and to form water-repellent and oil-repellent layer on the surface of the metal oxide layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cage for use in a ball bearing, the ball bearing cage having a water / oil repellent film formed on the surface thereof.

  In order to rotatably support a rotating portion (for example, a rotating shaft) of various devices, for example, a ball bearing as shown in FIG. The ball bearing includes a bearing ring (for example, an inner ring 2 and an outer ring 4) that are opposed to each other so as to be relatively rotatable, and a plurality of rolling elements 6 (that is, balls) that are rotatably incorporated between the inner and outer rings 2 and 4. And a cage 8 that rotatably holds the rolling elements (balls) 6 one by one. Here, in order to prevent leakage of lubricant (for example, grease, oil) enclosed in the bearing and entry of foreign matter (for example, water, dust) into the bearing, A sealing plate 10 such as a shield may be provided. In the drawing, as an example, a seal is shown in which the proximal end side is fixed to the outer ring 4 and the distal end side is positioned in sliding contact with the inner ring 2.

  Various types of cages 8 such as corrugated press cages and angular ball cages are known as cages 8 incorporated in such ball bearings. Here, as an example, for example, as shown in FIG. A simple crown-shaped cage is assumed. The crown-shaped cage (hereinafter referred to as cage 8) has a plurality of pockets 8p formed at equal intervals along the circumferential direction. Each pocket 8p has an opening Pk on one side and is closed on the other side. Has been. Further, a pair of claw portions 8r are raised from both sides in the circumferential direction of each opening Pk so as to partially cover the opening Pk, and the size of the opening Pk (that is, the opening diameter) is narrowed by these claw portions 8r. It has been.

  In this case, for example, when the rolling element (ball) 6 is pushed toward the opening Pk from the state where the rolling element (ball) 6 is positioned on the pair of claw parts 8r, the pair of claw parts 8r are elastically deformed outward by the pushing force. Then, when the opening Pk is expanded (expanded), the rolling elements (balls) 6 can be inserted from the opening Pk into the pocket 8p. When the rolling elements (balls) 6 are inserted into the pockets 8p, the pair of claw portions 8r is elastically restored to the original shape, whereby the dimension (opening diameter) of the opening Pk is narrowed again. At this time, the rolling elements (balls) 6 are held in the pocket 8p by the pair of claw portions 8r. In this state, each rolling element (ball) 6 is rotatably held in the pocket 8p without falling off from each pocket 8p.

  Such a cage 8 is assembled between the inner ring 2 and the outer ring 4 of the ball bearing while holding a plurality of rolling elements (balls) 6 (FIG. 2 (a)), and each rolling element is rotated during bearing rotation. Revolves at a speed about half the revolution speed of (ball) 6. Here, examples of a method for guiding the cage 8 that revolves between the inner and outer rings 2 and 4 include a rolling element guide, an outer ring guide, and an inner ring guide. In particular, a bearing having a small diameter of the rolling element (for example, a small diameter bearing, The inner ring guide system is applied to the miniature bearing.

  By the way, the above-described cage 8 has various specifications in order to reduce the torque when the bearing rotates. As an example, Patent Document 1 discloses a cage in which a large number of protrusions are formed on the inner surface of each pocket (for example, the pocket inner peripheral surface Ps shown in FIG. 2B). According to this, by narrowing the range in which a thin oil film is formed between the pocket inner peripheral surface and the surface of the rolling element (ball) by a large number of protrusions, the oil film acting between both surfaces is sheared. By reducing the resistance, a reduction in torque (reduction of dynamic torque) during rotation of the bearing is achieved.

  However, with respect to the cage of Patent Document 1, a non-contact portion between the pocket inner peripheral surface and the surface of the rolling element (ball) (for example, a portion of the pocket inner peripheral surface where no protrusion is formed and the rolling element (ball). It is demanded that the shear resistance of the oil film be further reduced between the surface of the oil film and the torque reduction (reduction of dynamic torque) during the rotation of the bearing.

  As another example, Patent Document 2 discloses a cage in which a film made of an oil repellent is formed on the outer surface (the entire surface including the pocket inner peripheral surface). According to this, when the cage revolves during the rotation of the bearing, the lubricant (oil) is restrained from being mixed with the cage and the stirring resistance is reduced, thereby reducing the torque during the rotation of the bearing (rotation torque). Reduction).

  However, in the cage of Patent Document 2, since the film made of the oil repellent is easily peeled off at the contact portion between the pocket inner peripheral surface and the surface of the rolling element (ball), when the film is peeled off, The rotational torque during the rotation of the bearing increases, and as a result, it becomes difficult to keep the effect of the low torque constant over a long period of time.

  Therefore, it is possible to reduce the shear resistance of the oil film acting between the pocket inner peripheral surface and the surface of the rolling element (ball), and to keep the effect of low torque at the time of bearing rotation constant over a long period of time. Although development of possible cages is desired, no such cage is currently known.

JP 2001-241448 A JP 2007-32806 A

  The present invention has been made to solve such a problem, and its purpose is to reduce the shear resistance of the oil film acting between the pocket inner peripheral surface and the surface of the rolling element (ball), and to rotate the bearing. An object of the present invention is to provide a ball bearing cage capable of maintaining the effect of torque reduction at a constant time over a long period of time.

In order to achieve such an object, the present invention provides a ball bearing retainer that revolves along the inside of the bearing together with the plurality of rolling elements while holding the plurality of rolling elements rotatably within the bearing. The cage includes a cage body having a plurality of pockets for rotatably holding a plurality of rolling elements one by one, and a plurality of protrusions formed by partially projecting the inner surface of each pocket, A water / oil repellent film is formed on the surface of the cage body so as to cover at least a plurality of protrusions formed on the inner surface of each pocket.
In the present invention, the water / oil repellent film is formed by forming a metal oxide layer on the surface of the cage body and forming a water / oil repellent layer on the surface of the metal oxide layer. In this case, in the state where the rolling element is held in each pocket, the plurality of protrusions have a contact area between the inner surface of the pocket and the surface of the rolling element when the surface of the rolling element contacts the protrusion. limit.

  According to the present invention, the shear resistance of the oil film acting between the pocket inner peripheral surface and the surface of the rolling element (ball) is reduced, and the effect of reducing the torque at the time of rotating the bearing is kept constant over a long period of time. It is possible to realize a ball bearing cage that can continue to be performed.

(a) is a perspective view showing a configuration of a ball bearing cage according to an embodiment of the present invention, (b) is a part of the configuration around the pocket of the cage shown in FIG. FIG. 5C is an enlarged view, FIG. 5C is a partially enlarged view showing the configuration around the pocket of the cage according to the modified example of the present invention, and FIG. 5D is a diagram illustrating the formation of a water / oil repellent film on the surface of the cage body. Sectional drawing which partially enlarges and shows a pocket periphery structure in the comprised holder | retainer. (a) is sectional drawing which expands and shows the structure of a ball bearing partially, (b) is a perspective view which shows the structure of the conventional cage for ball bearings.

Hereinafter, a ball bearing retainer according to an embodiment of the present invention will be described with reference to the accompanying drawings.
Since the present embodiment is an improvement of the cage 8 shown in FIGS. 2A and 2B, only the improved portion will be described below. In this case, for the same configuration as the above-described cage 8 (FIGS. 2A and 2B), the same reference numerals as those used for the configuration are attached to the drawings used in the present embodiment. Therefore, the description is omitted.

  As shown in FIGS. 1 (a), (b), and (d), the cage 8 according to the present embodiment is capable of rotating a plurality of rolling elements (balls) 6 (FIG. 2 (a)) one by one. And a plurality of projections 8t formed by partially projecting the inner surface Ps (inner pocket inner surface) of each pocket 8p. A water / oil repellent film 8b is formed on the entire surface.

  Here, the plurality of protrusions 8t are configured to be scattered at predetermined intervals at a plurality of locations on the pocket inner peripheral surface Ps. In this case, the locations and intervals to be interspersed are arbitrarily set according to the area and shape of the pocket inner peripheral surface Ps, and are not particularly limited here. The size and the amount of protrusion of each protrusion 8t are, for example, the relationship between the width of the pocket inner peripheral surface Ps and the size of the rolling element (ball) 6, or the relationship between the pocket inner peripheral surface Ps and the rolling element (ball) 6. Since it is arbitrarily set depending on the degree of the gap, there is no particular limitation here. The shape of each protrusion 8t can be set to various shapes such as a rectangular cross section, a triangular cross section, and a circular arc shape.

  In short, the plurality of protrusions 8t are formed in such a manner that the surface of the rolling element (ball) 6 comes into contact with the protrusion 8t in a state where the rolling element (ball) 6 is held in each pocket 8p. What is necessary is just to set so that the contact area of Ps and the surface of the rolling element (ball) 6 may be limited. That is, according to the plurality of protrusions 8t, the surface of the rolling element (ball) 6 held in the pocket 8p comes into contact with the protrusion 8t, so that the pocket inner peripheral surface Ps and the surface of the rolling element (ball) 6 are The contact area can be reduced as compared with the case where is in direct contact.

In addition, as a material of the cage main body 8a, for example, a commercially available general synthetic resin material or metal material can be applied.
Here, as the synthetic resin material, for example, a polyamide-based synthetic fiber or a synthetic resin material reinforced with a polyamide-based synthetic fiber as a base material can be applied. As the polyamide-based synthetic fiber, for example, a polyamide-based resin (PA66) produced by polycondensation of adipic acid and hexamethylenediamine, and heat resistance, wear resistance, impact resistance, and oil resistance are superior to the PA66. Polyamide resin (PA46) or the like can be applied.
On the other hand, as the metal material, for example, high carbon chromium steel (SUJ2), stainless steel plate (SUS304), or the like can be applied.

  The cage 8 according to the present embodiment is configured by forming the cage body 8a from the above-described synthetic resin material or metal material, and forming the water / oil repellent film 8b on the surface of the cage body 8a. Yes. Here, the water / oil repellent film 8b is formed by forming a metal oxide layer on the surface of the cage body 8a and forming a water / oil repellent layer on the surface of the metal oxide layer. In this case, as a method for forming the water / oil repellent film 8b on the surface of the cage body 8a, the following film forming method may be applied.

  In such a film forming method, a first solution containing water and at least one alkoxy metal salt as essential components, a second solution which is an alkaline solution having a pH of 11 to 13, and a solution containing a fluorine-containing organic compound. A third solution and a fourth solution that is an alkaline solution having a pH of 9 to 14 are prepared. Then, the retainer body 8a formed of the synthetic resin material as described above is sequentially brought into contact with these four solutions. In addition, pH means a hydrogen ion index or a hydrogen ion concentration index, and is a numerical value indicating the degree of acidity or alkalinity of a substance.

  That is, after bringing the cage body 8a into contact with the first solution, the metal oxide layer is formed on the surface of the cage body 8a by bringing it into contact with the second solution (first step). Subsequently, the cage body 8a having the metal oxide layer formed on the surface is brought into contact with the third solution, and then brought into contact with the fourth solution, whereby the water and oil repellent layer is formed on the surface of the metal oxide layer. Form (second step).

  Thereby, the cage 8 (FIGS. 1A, 1B, and 1D) in which the surface of the cage body 8a is covered with the water / oil repellent film 8b can be realized. In this case, the water / oil repellent film 8b has characteristics excellent in heat resistance and oil resistance. Therefore, the cage constituted by forming the water / oil repellent film 8b on the surface of the cage body 8a. 8, the shear resistance of the oil film acting between the pocket inner peripheral surface Ps and the surface of the rolling element (ball) 6 can be reduced, and the effect of lowering the torque during the rotation of the bearing can thereby be prolonged. It can be kept constant throughout.

  In addition to the effects described above, a plurality of protrusions 8t are formed on the pocket inner peripheral surface Ps, so that the rolling elements (balls) 6 are held in the pockets 8p with respect to the protrusions 8t. By contacting the surface of the (ball) 6, the contact area between the pocket inner peripheral surface Ps and the surface of the rolling element (ball) 6 can be limited. That is, according to the plurality of protrusions 8t, the surface of the rolling element (ball) 6 held in the pocket 8p comes into contact with the protrusion 8t, so that the pocket inner peripheral surface Ps and the surface of the rolling element (ball) 6 are The contact area can be reduced as compared with the case where is in direct contact. Thereby, the pocket inner peripheral surface Ps, the surface of the rolling element (ball) 6 and the non-contact portion (that is, the portion of the pocket inner peripheral surface Ps where the protrusion 8t is not formed and the surface of the rolling element (ball) 6 are formed. The water / oil repellent film 8b is not easily peeled off, and as a result, the effect of lowering the torque during rotation of the bearing can be kept constant over a long period of time.

Here, the specific contents of the four first to fourth solutions described above will be supplementarily described.
The above-mentioned first solution is an alkoxy metal salt that is a tetra (or tri) alkylalkoxy metal salt in which the metal species is silicon, titanium, or aluminum and the alkyl part is lower alkyl having 1 to 6 carbon atoms, Or it is preferable to contain the tetra (or tri) halogen alkoxy metal salt.
In the case of a halogen alkoxy metal salt, chlorine is preferred as the halogen, the alkyl moiety is preferably a methyl, ethyl, propyl, or butyl group, and the metal species of the alkoxy metal salt are preferably silicon, titanium, or aluminum.

  The first and third solutions described above preferably further contain a lower alcohol having 1 to 6 carbon atoms. Thereby, the solubility of the alkoxy metal salt having lower alkyl or halogen can be increased, and a more stable solution can be obtained. As the lower alcohol having 1 to 6 carbon atoms, methanol, ethanol, 1-propanol, 2-propanol, butanol, hexanol, cyclohexanol and the like can be preferably used. More preferably, ethanol may be used.

  In this case, the pH of the first and third solutions described above is preferably 6 or less. Thus, by making pH into 6 or less, the hydrolysis reaction of an alkoxy metal salt is accelerated | stimulated, and it becomes easy to form a metal oxide layer on the to-be-film-formed member surface (for example, surface of the holder main body 8a). The pH is preferably 1 to 6, more preferably 1 to 5, and most preferably 2 to 4. Moreover, it is preferable to adjust pH of a 1st solution using inorganic acids, such as hydrochloric acid, nitric acid, and a sulfuric acid. In particular, it is preferable to use hydrochloric acid. It is also preferable to stabilize the pH using various pH buffer solutions.

  The first solution preferably contains metal oxide fine particles having an average particle size of 1 nm or more and 200 nm or less in a proportion of 0.1 or more and 5.0% by weight or less. Silicon, titanium, and aluminum can be used as the metal species of the metal oxide. That is, the first solution preferably contains fine particles made of silica, titania, or alumina having an average particle diameter of 1 nm to 200 nm in a proportion of 0.1 to 5.0% by weight.

  Further, it is particularly preferable that the metal species of the metal oxide forming the metal oxide fine particles and the metal species of the alkoxy metal salt are the same. When the metal oxide fine particles are added to the first solution, an oxide of an alkoxy metal salt is generated on the surface of the film forming member (for example, the surface of the cage body 8a), and the film forming member. The metal oxide particles are bonded to the surface, so that the metal oxide layer becomes dense. Further, irregularities due to the fine particles are formed on the surface of the formed metal oxide layer, and the surface area ratio is increased. When the surface area ratio of the metal oxide layer increases, the surface area ratio of the water and oil repellent layer, which is the upper layer, also increases and a dense water and oil repellent layer is formed. The oil repellency is improved and the water / oil repellency film is firmly bonded to the surface of the film forming member.

  Here, the average primary particle size of the metal oxide fine particles is preferably 2 nm to 100 nm, more preferably 2 nm to 80 nm, and still more preferably 10 nm to 50 nm. Moreover, it is also possible to mix and use metal oxide fine particles having different average primary particle sizes. When the average primary particle size is less than 1 nm, the effect of increasing the surface area ratio is small, and when it exceeds 200 nm, the film tends to fall off from the surface of the film forming member.

  The content of the metal oxide fine particles in the solution is preferably 0.1 or more and 3% by mass or less, and more preferably 0.2% by mass or more and 2.5% by mass or less. When the content of the metal oxide fine particles in the solution is less than 0.1% by mass, the effect of densifying the metal oxide layer is small, and when the content exceeds 5% by mass, the metal oxide fine particles are formed on the surface of the film forming member. Deposition tends to occur in the water- and oil-repellent film due to the fine particles falling off along with the accumulation.

  The shape of the metal oxide fine particles is not particularly limited, and a spherical shape, a rectangular shape, a flat shape, a fiber shape, a whisker shape, or the like can be used. For example, if it is a fibrous thing, the length of a fiber can be 1 nm or more and 200 nm or less. Moreover, you may mix and use the thing of a different shape. Moreover, if an average primary particle diameter is 1 nm or more and 200 nm or less, a porous thing etc. can also be used.

Further, the surface of the metal oxide fine particles may be subjected to various hydrophobizing treatments and hydrophilizing treatments, but is preferably a hydrophilic surface or not subjected to chemical surface treatment. It is desirable.
An example of the composition of the first solution described above is specifically described. The alkoxy metal salt is 1% by mass to 10% by mass, the water is 1% by mass to 20% by mass, and the alcohol is 30% by mass to 95% by mass. Hereinafter, the metal oxide fine particles are 0.1 mass% or more and 5 mass% or less, and the pH is adjusted to 6 or less with hydrochloric acid.

  The first solution of this composition, in particular, when metal oxide fine particles are contained, is mixed in advance with components other than hydrochloric acid and stirred for several tens of minutes to several hours so that the metal oxide fine particles are uniform. Finally, it is preferable to adjust the pH using hydrochloric acid. Highly pure water and hydrochloric acid are preferred.

  The second and fourth solutions described above are preferably aqueous solutions of alkali metal salts (sodium hydroxide, potassium hydroxide, etc.), and particularly preferably aqueous sodium hydroxide solutions. Further, alkali metal carbonates such as sodium carbonate, potassium carbonate and sodium hydrogen carbonate can also be used. Various pH buffering agents may be used in combination. Moreover, you may make with the mixed solvent of C1-C6 lower alkyl alcohol and water as needed. It is desirable that water and these components have high purity.

  In this case, the pH of the second and fourth solutions is preferably pH 11 or more and pH 13 or less. When the pH is less than 11, the bonding effect of the metal oxide layer to the film-formed member surface and the bonding strength effect of the water / oil repellent layer to the metal oxide layer are small, and when the pH is 13 or more, the bonding is weakened. There is a risk that.

The fluorine-containing organic compound contained in the third solution is preferably any one of a fluorine-based surfactant, a fluorine-based coupling agent, and a fluorine-based polymer, or a mixture thereof.
The fluorine-containing organic compound contained in the third solution is preferably a fluorine-based coupling agent containing silicon, titanium, or aluminum. Furthermore, it is preferable that the metal species of the metal oxide used in the first solution described above or the same metal species as the metal species of the alkoxy metal salt used in the first solution described above.

  Specifically, 1H, 1H, 2H, 2H, -perfluorodecyltriethoxysilane, 1H, 1H, 2H, 2H, -perfluorodecyltrimethoxysilane, 1H, 1H, 2H, 2H, -perfluorodecyltri Chlorosilane-3-heptafluoroisopropoxypropyltrichlorosilane, 1H, 1H, 2H, 2H, -perfluorododecyltriethoxysilane, 3-trifluoroacetoxypropyltrimethoxysilane and the like can be used.

  In the rolling bearing cage 8 of the present embodiment, the method for forming the water / oil repellent film 8b on the surface of the film forming member (for example, the surface of the cage body 8a) includes the film forming member (holding). A step of bringing the vessel body 8a) into contact with a liquid containing a fluorine-based coupling agent containing silicon, titanium, or aluminum, water, and a lower alcohol having 1 to 6 carbon atoms and having a pH of 6 or less; After this step, a step of contacting with a solution containing an alkali metal salt and having a pH of 11 to 13 is included.

  There are no particular limitations on the film forming member to which such a film forming method can be applied, as long as it is a solid containing a resin or metal, but the surface of the film forming member may be covered with an oxide-based material. preferable. Specifically, it is an inorganic substance (including metal). Among inorganic materials, glass and ceramics are preferable. Glass is mainly composed of silica, and ceramics and metals are outermost oxide layers when viewed microscopically. Among these, glass and metal are preferable. Among metals, iron-based metals are preferable. Among these, steel such as bearing steel and stainless steel is preferable. In particular, the stainless steel is preferably subjected to a passivation treatment.

  In the film forming method described above, it is preferable to perform the first step described above on the surface of the film forming member having an average surface roughness (Ra) of 0.001 μm or more and 4 μm or less. Moreover, it is preferable to perform the first step described above on the surface of the film forming member having a surface area ratio of 1.1 or more. Thereby, the water / oil repellent performance of the formed water / oil repellent film is improved as compared with the case where the average surface roughness (Ra) is less than 0.001 μm and the surface area ratio is less than 1.1. be able to. In addition, when metal fine particles are contained in the first solution, a further improvement in water and oil repellency can be expected due to a synergistic effect with the surface property effect as described above. In addition, if average surface roughness (Ra) exceeds 4 micrometers Ra, the application range as a member of various uses will be restricted.

Normally, various processing methods such as machining, chemical processing, and optical processing are performed in order to make the surface of the film-forming member within the above-mentioned range. As the mechanical processing, grinding, cutting, pressing, barrel, shot, etc. Examples include blasting. Examples of the chemical processing include electrolytic polishing, chemical polishing, various platings, various surface treatments, and the like. As optical processing, a femtosecond laser or the like can be used. Moreover, you may combine these processes.
The surface area ratio is the ratio of the surface area determined geometrically to the surface area measured including surface roughness and waviness. The surface area ratio approaches 1 as it approaches the so-called mirror surface. In some cases, it exceeds 1. The surface area ratio can be obtained by measuring the surface of the film forming member with a scanning probe microscope (SPM) or an atomic force microscope (AFM) which is a kind of SPM.

In the film forming method described above, the film forming member (the cage body 8a) is brought into contact with the first solution in the first step. It is preferable to remove foreign substances adhering to the surface of the film forming member.
In this case, as a method for bringing the film formation member into contact with the first solution, a general method such as a dipping method, a spray method, or a spin coating method can be used. In the immersion method, ultrasonic waves are used to move the first solution to the depth of the surface of the film-forming member, the film-forming member is moved in the solution, or the pressure is reduced below atmospheric pressure. It is possible to use a method such as In particular, when metal fine particles are contained in the first solution, it is preferable to immerse the film forming member while stirring the first solution so that the fine particles are uniformly dispersed in the solution.

  The time for which the first solution and the film forming member are in contact with each other can be appropriately adjusted depending on the shape, surface area, and the like of the film forming member. In addition, it is preferable that the temperature of the first solution at the time of bringing the first solution into contact with the deposition target member is 0 ° C. or more and 100 ° C. or less, and the change during the contact process is small. When the temperature is lower than 0 ° C., the viscosity of the first solution is increased, and the first solution is difficult to reach the depth of the roughness of the film-formed member surface. When it exceeds 100 ° C., the evaporation of the components of the first solution increases, and the component ratio may change.

When the film forming member (the cage body 8a) is a metal, the temperature of the first solution is preferably 60 ° C. If it exceeds 60 ° C., the chemical activity of the first solution becomes too high, and the metal surface may be corroded. More preferably, it is 40 degrees C or less. In the case where the deposition target member is a metal, the contact time with the first solution is preferably 2 hours or less. If the contact time exceeds 2 hours, the metal surface may be corroded. The lower limit of the contact time is not particularly defined, but is preferably at least 1 second or more in order to spread the first solution over the entire surface of the film forming member.
In the case where a water / oil repellent film is formed on a part of the surface of the film forming member, the above-described film forming method may be carried out after previously masking the part not to be formed. In this case, various resists can be used as the mask.

  In the film forming method described above, it is preferable that the film forming member is immediately brought into contact with the second solution after the film forming member is brought into contact with the first solution for a predetermined time. Here, a step of removing the liquid adhering to the surface of the film forming member may be provided before the film forming member is brought into contact with the second solution. As a method for removing the adhered liquid, a method of draining using centrifugal force, a method of draining using clean air or inert gas, and the like can be used. In addition, a method such as wiping in which a solid material is brought into direct contact with the surface of the film forming member is not preferable.

Further, the method for bringing the film-forming member into contact with the second solution, and the contact conditions such as temperature and time are the same as in the case of contact with the first solution.
Here, the film-forming member after being brought into contact with the second solution may be brought into contact with the third solution, which is the first step of the second step described above, quickly. It is preferable to provide a drying step after contact with. A strong metal oxide layer is formed on the surface of the film forming member by contact with the second solution, so that the metal oxide layer is more firmly fixed to the surface of the film forming member by drying once. Can be made. However, it is preferable to remove the second solution adhering to the film formation member surface before drying. In addition, as a method of removing the adhering liquid, cleaning with alcohol or the like, a method of draining using centrifugal force, a method of draining using clean air or inert gas, and the like can be used. Moreover, in order to dry after removing the adhering liquid by these methods, it is also possible to heat. Preferably, it is maintained at a temperature of about 50 to 100 ° C. for several minutes to several hours.

In addition, after making a film-forming member contact with the above-mentioned 2nd solution, it is made to contact with the above-mentioned 3rd solution. In this case, the contact method such as the contact method with the third solution, the temperature, and the time are the same as those in the contact with the first solution.
Moreover, after making a film-forming member contact with the above-mentioned 3rd solution, it is made to contact with the above-mentioned 4th solution. In this case, the contact method with the third solution and the fourth solution in the second step, the transition method from the contact with the third solution to the contact with the fourth solution, conditions such as temperature, time, etc. The transition method and the conditions from the contact with the first solution to the contact with the second solution are the same.

  Then, by holding the film forming member in contact with the above-described fourth solution, the holding member having the water / oil repellent film 8b in which the water / oil repellent layer is firmly formed on the surface of the metal oxide layer on the cage body 8a. A device 8 (FIGS. 1 (a), (b), (d)) can be realized. Thereafter, it is preferable to perform a liquid draining or washing step and a drying step. The specific method, temperature, time, and other conditions for these steps are the same as the method and conditions for transition from contact with the second solution to contact with the third solution.

  In the above embodiment, the case where the water / oil repellent film 8b is formed over the entire surface of the cage body 8a has been described. However, instead of this, only the inner surface Ps of each pocket 8p is repelled. The water / oil repellent film 8b may be formed to cover the plurality of protrusions 8t formed on the pocket inner peripheral surface Ps. By forming the water / oil repellent film 8b so as to cover at least the plurality of protrusions 8t formed on each pocket inner peripheral surface Ps, it is possible to achieve the same effect as the above-described embodiment.

  In the above-described embodiment, for example, the shape of the pocket 8p of the general crown-shaped cage 8 as shown in FIG. 1B has been described, but as a modification thereof, FIG. The configuration of the above-described embodiment can also be applied to the cage 8 having the pocket 8p having the shape shown in FIG. In the pocket 8p of FIG. 1 (c), planar portions 8h are formed on the pocket inner peripheral surface Ps so as to be parallel to each other toward the opening Pk. Each planar portion 8h includes the planar portion 8h. A plurality of projections (not shown) formed by partially projecting are provided. As a result, the same effects as those of the above-described embodiment can be realized. In particular, in the present modification, the oil film shearing acting between the pocket inner peripheral surface Ps and the surface of the rolling element (ball) 6 can be realized. The resistance can be “more” reduced compared to the embodiment described above.

  In the above-described embodiment, the crown-shaped cage 8 is assumed, but instead of this, for example, various types such as a corrugated press cage and an angular ball cage are configured in the above-described embodiment. Needless to say, the same effect can be realized.

  Further, a film formation method different from the above-described embodiment may be adopted. For example, after sufficiently removing impurities such as dust and cutting oil from each part of the cage body 8a and cleaning them, volatilization with respect to the lubricant enclosed in the ball bearing of FIG. A water- and oil-repellent agent that does not dissolve (for example, the first to fourth solutions described above) is applied to each part of the cage body 8a and sufficiently dried. As the water and oil repellent used here, a fluorine water and oil repellent may be applied when the lubricant enclosed in the ball bearing is not a fluorine lubricant.

8 Cage 8a Cage body 8b Water / oil repellent film 8p Pocket 8t Protrusion Ps Inside surface of pocket (inner surface of pocket)

Claims (3)

A ball bearing retainer that revolves along the inside of the bearing together with the plurality of rolling elements while holding the plurality of rolling elements in a rotatable manner inside the bearing,
The cage includes a cage body having a plurality of pockets for rotatably holding a plurality of rolling elements one by one, and a plurality of protrusions formed by partially projecting the inner surface of each pocket,
A cage for ball bearings, wherein a water- and oil-repellent film is formed on the surface of the cage body so as to cover at least a plurality of protrusions formed on the inner surface of each pocket.   2. The water / oil repellent film according to claim 1, wherein a metal oxide layer is formed on a surface of a cage body, and a water / oil repellent layer is formed on the surface of the metal oxide layer. The ball bearing retainer described.   The plurality of protrusions limit a contact area between the inner surface of the pocket and the surface of the rolling element by contacting the surface of the rolling element with the protrusion in a state where the rolling element is held in each pocket. The cage for ball bearings according to claim 1 or 2 characterized by these.

Images