JPH10325414A - Straight moving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use under the environment of a clean atmosphere or the atmosphere with a high temperature, vacuum and corrosion property by filming a fluorine resin film on the surface through an electroless nickel film to at least one of a pair of moving members or rolling element. SOLUTION: A ceramics film 20 is formed on the entire surface of the bearing steel or stainless steel, in a guide shaft 2 and slider 3. An electrodess nickel film 21 improves the adhesiveness of a fluorine resin film 22 and a ball 4. For example, the nickel film with a submicron degree is formed on the ball 4 of the stainless steel by an electrolytic nickel plating after organic solvent cleaning, acid treatment and electrolytic cleaning and then a film is formed by soaking to a nickel plating bath and electroless plating. The fluorine resin film 22 is formed by soaking into a solution in which a particle consisting of the fluorine resin and a proper binder and a surfactant is dispersed to a proper solvent. The adhesiveness between the fluorine resin film and a covered surface is improved by the anchor effect of the electroless nickel film and the fall out of the fluorine resin and an excessive stick are prevented and the generation of a dust is restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a linear guide, a ball spline, a ball screw, a cross roller bearing, and the like, in which one moving member and the other moving member are relatively moved via rolling elements in contact with respective guide surfaces. The linear motion device moves linearly, and can be suitably used especially in an environment requiring a clean atmosphere such as a clean room, a semiconductor manufacturing device, a liquid crystal panel manufacturing device, and a food processing device. The present invention relates to the linear motion device which can be used even in an atmosphere environment.

[0002]

2. Description of the Related Art Linear motion devices such as linear guides, ball splines, ball screws, and cross roller bearings are used in various fields. However, in these linear motion devices, lubrication oil or grease is used to lubricate the lubricating oil or grease to the outside during operation of the device, or the lubricating oil or grease evaporates at high temperatures or in a vacuum environment. It pollutes the external environment, such as releasing gas. Therefore, in applications that require a clean environment, such as clean rooms, semiconductor manufacturing equipment, liquid crystal panel manufacturing equipment, and food processing equipment, or in vacuum environments, a structure that lubricates with normal lubricating oil or grease is used. The linear motion device cannot be used.

Therefore, in applications requiring a clean environment or in a vacuum environment, a self-lubricating composite material in which a solid lubricant or the like is mixed in a cage is used, or each component of a linear motion device is used. Lubrication using a solid lubrication linear motion device in which a coating made of a solid lubricant is previously formed on the surface of the surface (for example, the guide surface of a moving member or the surface of a rolling element), or a fluorine-based grease having a low vapor pressure and a small consistency. A linear motion device having the following structure is used. In a linear motion device incorporating a cage having self-lubricating properties, the cage and the rolling element slide along with the operation of the device, and are transferred from the cage to the guide surface of the moving member and the surface of the rolling element. The linear motion device is lubricated by the thin solid lubricating film formed as described above. On the other hand, in a linear motion device provided with a solid lubricating film, the film made of solid lubricant previously formed on the guide surface of the moving member of the linear motion device or the surface of the rolling element may be sheared, cleaved, etc. as the device operates. Then, the linear motion device is lubricated by preventing direct contact of the base material. As the solid lubricating film, a soft metal such as gold, silver, or lead, a layered compound such as molybdenum disulfide or tungsten disulfide, graphite, or a fluororesin such as polytetrafluoroethylene is used. However, the soft metal and the layered compound generate a relatively large amount of dust and cannot be used for applications requiring a high-grade cleaning environment. It is known that solid lubricants have different lubricating properties depending on the atmosphere in which they are used, for example, molybdenum disulfide exhibits its true value in a vacuum and graphite exhibits its true value in the atmosphere. However, especially in semiconductor manufacturing equipment and liquid crystal manufacturing equipment, it is necessary to use a lubricant that exhibits lubricity both in vacuum and in the air, because reciprocation between air and vacuum is repeated for transport between processes. In such an environment, a fluororesin is often used as a lubricating film.

[0004]

In recent years, high integration and miniaturization of various electronic elements such as semiconductor elements have been advanced. Along with this, the influence of minute particles adhering to the surface of a semiconductor element or the like during the manufacturing process on the performance, reliability, yield, and the like of the product is increasing. For this reason, linear motion devices used in places requiring a clean environment, such as semiconductor manufacturing equipment, are required to reduce the amount of particles and gases that scatter outside the equipment. There is a tendency to increase. Also, there is a similar demand for liquid crystal panels in order to increase the number of pixels and improve image quality.

However, in any of the above-described solid lubrication linear motion devices, it is inevitable that abrasion particles and the like are generated from a sliding portion as the cage slides with the coating and the like and fall off. Is scattered outside the device. Further, even in a linear motion device having a structure lubricated with fluorine-based grease, the grease is sheared with the operation of the device and scatters outside the device. Furthermore, linear motion devices used in semiconductor manufacturing devices and liquid crystal panel manufacturing devices are sometimes used under corrosive atmospheres such as acids and alkalis, and food processing devices often come in contact with water, The generated rust becomes dust and contaminates the external environment. For this reason, there is a situation in which the above-mentioned request cannot be sufficiently satisfied.

Accordingly, the present invention can be suitably used in an environment requiring a clean atmosphere, such as a semiconductor manufacturing apparatus, a liquid crystal panel manufacturing apparatus, and a food processing apparatus.
It is an object of the present invention to provide a linear motion device that can be used in a high-temperature, corrosive atmosphere environment and generates little dust from the device.

[0007]

In order to solve the above-mentioned problems, a linear motion device according to the present invention is arranged such that one moving member and the other moving member move relative to each other via rolling elements which are in contact with respective guide surfaces. In a device that moves linearly, at least one of the two moving members or the rolling elements has a fluororesin film formed on its surface via an electroless nickel film.

In order to solve the same problem, a linear motion device according to the present invention is a device in which one moving member and the other moving member relatively linearly move via rolling elements contacting respective guide surfaces. In at least one of the two moving members or rolling elements, a film made of a fluororesin is formed on the surface thereof via an electroless nickel film, and particles made of the fluororesin are contained in the electroless nickel film. It is characterized by being impregnated.

Further, in each of the linear motion devices described above, at least one of the guide surfaces or the whole of the two moving members or the surface or the whole of the rolling element is made of ceramics.

According to the linear motion device of the present invention, at least one of the guide surface or the rolling element of the moving member in which rolling friction or sliding friction occurs is coated with a film made of a fluororesin via an electroless nickel film. The anchoring effect of electroless nickel improves the adhesion between the fluororesin coating and the coated surface. As a result, it is possible to prevent the moving member of the fluororesin from dropping off from the guide surface or the rolling element or the like, and to prevent excessive transfer to the guide surface or the rolling element, to suppress dust generation, and to provide excellent lubrication for a long time. Is maintained. Here, the electroless nickel coating is an electroless nickel (Ni-) coating, an electroless nickel-phosphorus (Ni-P) coating, and an electroless nickel-boron (Ni-B) coating. A film can be formed using a film forming technique. For example, an electroless nickel (Ni-) film is formed using hydrazine or the like as a reducing agent, an electroless nickel-phosphorous (Ni-P) film is formed using hypophosphite or the like as a reducing agent, and electroless nickel is used. -The boron (Ni-B) film is formed using sodium borohydride, aluminum borane or the like as a reducing agent.

In addition, fine cracks and pores are usually present in the electroless nickel coating. At the same time when the fluororesin coating is formed, the fluororesin particles are impregnated into the fine cracks and pores by impregnation. The penetration and the adhesion between the fluororesin coating and the electroless nickel coating are further improved. Further, even after the fluororesin coating has disappeared due to abrasion, the impregnated fluororesin particles function as a lubricant, so that the lubrication life is extended as compared with the case of the fluororesin coating alone. In addition, since the cracks and pores of the electroless nickel coating are blocked by the fluororesin particles, the invasion of corrosive gas and water through these cracks and pores is prevented, the corrosion resistance is improved, and dust is generated by rust. Can be prevented.

In addition, since at least one of the guide surface or the whole of the moving member or the surface or the whole of the rolling element is made of ceramics, the corrosion resistance of the linear motion device against acid and alkali is further improved, and dust due to rust is reduced. The generation is further prevented, and it can be used even in a highly corrosive environment.

Further, when an electroless nickel coating is provided,
The film itself has a rust-preventing action, and the corrosion resistance is further improved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a linear motion device according to the present invention will be described in detail with reference to the drawings. (First Embodiment: Linear Guide Bearing) First, a case where the present invention is applied to a linear guide bearing will be described below. The configuration of the linear guide bearing is not particularly limited, and may be, for example, the linear guide bearing shown in FIG. As shown, the linear guide bearing 1 includes a guide shaft 2 which is one of the moving members.
And a plurality of balls 4 as rolling elements are arranged between the slider 3 and the other moving member.

In the present invention, the guide shaft 2 and the slider 3 can be formed by forming a ceramic coating 20 on the entire surface of bearing steel or stainless steel. At this time, as the ceramic material, titanium nitride, titanium carbonitride, chromium nitride, or the like is excellent in adhesion and can be particularly preferably used. The thickness of the ceramic film 20 is 1
It is desirable that the thickness be 10 μm to 10 μm. As the film forming method, a known film forming technique such as a vacuum evaporation method, sputtering, ion plating, ion mixing, and CVD method can be adopted. In particular, when used in a highly corrosive environment, the entire guide shaft 2 and slider 3 are
Ceramics such as silicon nitride, silicon carbide, sialon, partially stabilized zirconia, and alumina can also be used. The ball 4 is made of stainless steel, and the entire surface thereof is covered with a fluororesin coating 22 via an electroless nickel coating 21.

Although the thickness of the electroless nickel coating 21 is not particularly limited, it is practically about 1 to 10 μm, preferably 2 to 7 μm. Further, since the electroless nickel film 21 is for improving the adhesion between the fluorine resin film 22 and the ball 4 described later, it is desirable that the film surface has irregularities. The electroless nickel film 21 is formed, for example, by subjecting the ball 4 to organic solvent cleaning, acid treatment, and electrolytic cleaning, forming a nickel film of about submicron by electrolytic nickel plating, and then immersing the ball 4 in a nickel plating bath. A film is formed by electrolytic plating.
The plating conditions may be the same as those for ordinary electroless nickel plating, for example, the pH is adjusted to 4.5 to 5.5,
The reaction is performed in an acidic nickel sulfate bath at a liquid temperature of about 90 ° C. using sodium hypophosphite as a reducing agent.

There is no particular limitation on the fluororesin, and polytetrafluoroethylene (hereinafter abbreviated as PTFE), polytrifluoroethylene, polytrifluorochloroethylene, hexafluoropropylene, polyvinyl fluoride,
Well-known fluororesins such as homopolymers or copolymers of polyvinylidene fluoride can be used.
A homopolymer of FE is preferable, and for example, a fluororesin sold under the registered trademark of Teflon (DuPont, USA) or Polyflon (Daikin Industries, Ltd.) can be suitably used. The fluororesin film 22 is formed by immersing in a solution (aqueous solution, alcohol, or the like) in which particles made of the above fluororesin, a suitable binder and a surfactant are dispersed in a suitable solvent. The thickness of the fluororesin film 22 is not particularly limited, but is preferably 0.1 μm or more in practical use. The fluororesin film 22 formed in this manner is more strongly formed by the interposition of the electroless nickel film 21 than in the case where the film is formed directly on the surface of stainless steel constituting the ball. Adhere to

Incidentally, the electroless nickel film 21 has
Usually, as shown in FIG. 2 as an enlarged sectional view of the surface of the ball 4, there are fine cracks 23 and voids (not shown). Such cracks 23 and pores reduce the adhesion to the electroless nickel film 21 and cause the base material (stainless steel) of the ball 4 to corrode through a corrosive atmosphere or the like. Therefore, in addition to the fluororesin coating 22, the cracks 23 and the pores of the electroless nickel coating 21 are more preferably impregnated with the particles of the fluororesin that forms the fluororesin coating 22 to close the cracks 23 and the pores. .

This impregnation is realized by immersing the ball 4 in a solution (aqueous solution, alcohol, or the like) in which fluororesin particles, a surfactant, and a binder are dispersed in a solvent.
Immersion times range from about 10 to 20 minutes. Here, the binder and the solvent are the same as those used at the time of forming the fluororesin film 22 described above. The particle size of the fluororesin particles is selected in consideration of the size of cracks 23 and pores in the electroless nickel coating 21. For example, in the case of the above-described electroless nickel coating 21 which is preferable in the present invention, the size of the crack 23 is 2-3 μm in width and 2-3 μm in depth.
From these data, the preferred particle size of the fluororesin particles is in the range of 0.1 to 1 μm. Also,
The liquid temperature during the immersion of the fluororesin particle dispersion is 30 to 80 ° C.
The immersion time of the ball 4 is preferably 10 to 20 minutes. Under the above conditions, the fluororesin film 22 is formed simultaneously with the impregnation of the fluororesin particles. The presence or absence of the impregnation is determined by analyzing in the depth direction by XPS, specifically, by performing XPS analysis while physically shaving the surface by argon ion etching.

By performing the impregnating treatment, the fluororesin particles enter the cracks 23 and pores of the electroless nickel coating 21, and the adhesion between the fluororesin coating 22 and the electroless nickel coating 21 is further improved. Further, even after the fluororesin coating 22 has disappeared due to abrasion, the fluororesin particles serve as a new lubricant supply source, and the lubrication life is extended as compared with the case where the fluororesin coating 22 is used alone. In addition, since the cracks 23 and the pores of the electroless nickel coating 21 are closed by the particles of the fluororesin, the corrosive atmosphere and the like are reduced.
The base material (stainless steel) of the ball 4 can be prevented from corroding through the holes and holes. As described above, since the impregnation treatment improves not only the lubricity but also the anticorrosion property, the guide shaft 2, the slider 3, and the ball 4, which constitute the linear guide bearing 1, are formed by the straight line of the fluororesin coating 22 alone. Unlike the guide bearing, it is not always necessary that all of the bearing components are made of ceramic (the surface or the whole), and if at least one is made of ceramic, excellent durability can be obtained. This is advantageous in terms of material costs.

Further, after immersion, if necessary, 200 to 3
By performing the heat treatment at a temperature of 00 ° C. for 2 to 5 hours, the hardness of the electroless nickel coating 21 is increased, and the wear resistance is improved or the surface of the fluororesin particles adsorbed or bonded to the surface by impregnation is improved. Adhesion can be improved.

The linear guide bearing 1 can be provided with seals and bellows at both ends of the slider 3 as in the conventional linear guide bearing.

FIG. 3 is a partially broken perspective view showing another embodiment of the linear guide bearing. This linear guide bearing 1 comprises a ball 41 made of ceramics,
A fluororesin film 22 is formed on the surface via an electroless nickel film 21, or balls 42 in which particles made of the fluororesin are impregnated in the electroless nickel film 21 are alternately arranged. It is composed. As ceramics, silicon nitride, silicon carbide, sialon, partially stabilized zirconia, alumina and the like can be used. Thereby, the effect obtained by coating the surface with the fluororesin film 22 via the electroless nickel film 21 or the film impregnated in the electroless nickel film 21 with particles made of the fluororesin further. In addition, the sliding contact with each other, or the material of the rolling contact can be made of different materials,
Since cohesive wear is reduced as compared with the case of using the same kind of material, abrasion, seizure and dust generation due to this can be prevented.

FIG. 4 is a partially broken perspective view showing still another embodiment of the linear guide bearing. In the linear guide bearing 1, a ball 4 is formed by forming a ball 43 made of polyimide or a fluororesin-based polymer material and a fluororesin coating 22 on the surface via an electroless nickel coating 21 or Further, balls 44 in which particles made of the fluororesin are impregnated in the electroless nickel film 21 are arranged alternately. As a result, the fluororesin coating 2 is formed via the electroless nickel coating 21.
2, or in addition to the effect obtained by coating the surface of the film impregnated in the electroless nickel film 21 with the particles made of the fluororesin,
Even after the fluororesin coating 22 and the fluororesin particles formed on the surface of the substrate have disappeared, the ball 43 made of polyimide or a fluororesin-based polymer material can serve as a lubricant supply source, further extending the lubrication life. it can.

FIGS. 1, 3 and 4 show a guide shaft 2 extended with an axial ball rolling groove on its outer surface, a guide shaft 2 which is loosely fitted to the guide shaft 2 and has a ball rolling groove. A slider 3 having a ball rolling groove facing the inner surface of the slider 3, and the guide shaft 2 and the slider 3 being rotatably fitted in the two rolling grooves.
A linear guide bearing of a type usually called a linear guide, comprising a number of balls 4 rolling and moving at the time of relative linear movement of the linear guide. Other linear guide bearings are of the type shown in FIGS. 5 and 6, and a coating similar to that described above can be formed thereon. That is, FIG.
Shows a linear guide bearing, usually called a linear ball bearing, which circulates through a circulation groove formed in the slider 3. In this linear guide bearing, a fluororesin film can be formed on the ball 4 via an electroless nickel film in the same manner as described above, or particles made of a fluororesin can be impregnated in the electroless nickel film. Also,
FIG. 6 shows a linear guide bearing having a so-called spline shaft in which a plurality of rolling grooves of rolling elements are formed linearly on the outer peripheral surface of a raceway member having a circular cross section. This linear guide bearing is of a type in which a rolling element is held on a raceway member via a retainer or the like so that it can only rotate on a rolling groove, and does not circulate. In this linear guide bearing as well, a fluororesin coating can be formed on the ball 4 via an electroless nickel coating in the same manner as described above, or particles made of a fluororesin can be impregnated in the electroless nickel coating.

In the above description, the configuration is such that the fluororesin coating is formed only on the ball as the rolling element via the electroless nickel coating, or the particles made of the fluororesin are further impregnated in the electroless nickel coating. Although shown, it is also possible to adopt a configuration in which a similar coating is formed on the guide shaft and the slider that are moving members.

(Second Embodiment: Cross Roller Bearing) Next, a case where the present invention is applied to a cross roller bearing will be described. The configuration of the cross roller bearing is not particularly limited, and may be, for example, a cross roller bearing shown in FIG. As shown, the cross roller bearing 10 includes:
A plurality of rollers 14 as rolling elements, which are guided and held by a retainer 13, are arranged between an inner ring 11 as one moving member and an outer ring 12 as the other moving member.

The roller 14 is made of bearing steel or stainless steel, and the entire surface thereof is coated with a fluororesin coating 22 via an electroless nickel coating 21. The thickness of the electroless nickel coating 21 is not particularly limited, but is practically 1 to 10 μm.
It is about 2 to 7 μm. The electroless nickel coating 21 is made of a fluororesin coating 22 described later.
In order to improve the adhesion between the roller and the roller 14, it is desirable that the surface of the coating has irregularities. This electroless nickel film 21 can be formed by the same method as the above-described linear guide bearing. The fluororesin is not particularly limited, and the same resin as the above-described linear guide bearing can be used. The method of forming the film is the same as that of the linear guide bearing described above. The film thickness of the fluororesin coating 22 is preferably 0.1 μm or more in practical use.

When used in a corrosive atmosphere, the inner ring 11 and the outer ring 12 can be formed by forming a ceramic film on the entire surface of bearing steel or stainless steel. At that time, titanium nitride,
Titanium carbonitride, chromium nitride, and the like are excellent in adhesion and can be particularly preferably used. The thickness of the ceramic film is desirably 1 to 10 μm. The film formation method is
Vacuum evaporation method, sputtering, ion plating,
Known film forming techniques such as ion mixing and CVD can be employed. In particular, when used in a highly corrosive environment, the entire inner ring 11 and outer ring 12 may be made of ceramics such as silicon nitride, silicon carbide, sialon, partially stabilized zirconia, and alumina. The retainer 13 is made of stainless steel,
The entire surface may be coated with a fluororesin coating 22 via an electroless nickel coating 21.

As described with reference to FIG. 2 in the linear guide bearing, the electroless nickel coating 21 has fine cracks 23 and pores. Therefore, the fluororesin coating 22
In addition, it is more preferable that the cracks 23 and the pores are impregnated with the particles of the fluororesin that forms the fluororesin film 22 so that the cracks 23 and the pores are closed. This impregnation can be performed in the same manner as in the case of the linear guide bearing. By performing the impregnation treatment, the adhesion between the fluororesin coating 22 and the electroless nickel coating 21 is further improved, the fluororesin particles serve as a new lubricant supply source to extend the lubrication life, Corrosion of the base material can be suppressed. Also, by performing the impregnation process, the inner ring 11 and the outer ring 12 constituting the cross roller bearing 10 are different from the cross roller bearing having the fluororesin coating 22 alone, and all the bearing components are necessarily made of ceramics (the surface or the whole). However, if at least one is made of ceramics, excellent durability can be obtained. This is advantageous in terms of material costs.

Further, after immersion, if necessary, 200 to 3
By performing the heat treatment at a temperature of 00 ° C. for 2 to 5 hours, the hardness of the electroless nickel coating 21 is increased, and the wear resistance is improved or the surface of the fluororesin particles adsorbed or bonded to the surface by impregnation is improved. Adhesion can be improved.

In FIG. 7, the roller 1 is
4 is a cross roller bearing of a type that guides and holds, but a full roller type cross roller bearing without a retainer may be used.

FIG. 8 is a perspective view showing another embodiment of the cross roller bearing. This cross roller bearing 10 is composed of a roller 51 made of ceramic and a fluororesin film 22 formed on the surface thereof through an electroless nickel film 21, or a particle made of the fluororesin. Rollers 52 impregnated in the electrolytic nickel coating 21 are alternately arranged. As ceramics, silicon nitride, silicon carbide, sialon, partially stabilized zirconia, alumina and the like can be used. Thereby, the effect obtained by coating the surface with the fluororesin film 22 via the electroless nickel film 21 or the film impregnated in the electroless nickel film 21 with particles made of the fluororesin further. In addition, the sliding contact with each other, or the material at the point of rolling contact can be composed of different materials, respectively, since the cohesive wear is reduced as compared with the case of the same kind of material, wear due to this, Seizure and dust generation can be prevented.

FIG. 9 is a perspective view showing still another embodiment of the cross roller bearing. This cross roller bearing 10
A roller 53 formed of polyimide or a fluororesin-based polymer material, and a fluororesin coating 22 formed on the surface via an electroless nickel coating 21 or And the rollers 54 in which the particles are impregnated in the electroless nickel coating 21 are arranged alternately. Thus, the effect obtained by coating the fluororesin film 22 via the electroless nickel film 21 or the surface of the film impregnated in the electroless nickel film 21 with particles made of the fluororesin is further improved. In addition, even after the fluororesin film 22 and fluororesin particles formed on the surface of the roller 54 have disappeared, the roller 53 made of polyimide or a fluororesin-based polymer material serves as a lubricant supply source, and further increases the lubrication life. Can be extended.

FIG. 10 is a perspective view showing still another embodiment of the cross roller bearing. This cross roller bearing 10
Has grooves 15 formed on opposing surfaces other than the V-shaped rolling grooves of the inner ring 11 and the outer ring 12 so as to be parallel to the operating direction of the outer ring 12. As described above, by having the grooves 15 on the surfaces opposed to each other other than the V-shaped rolling grooves in the inner ring 11 and the outer ring 12, when passing through the space between the inner ring 11, the outer ring 12, the retainer 13, and the roller 14, In addition, dust is captured and held by the groove, so that dust generation can be effectively prevented. In addition, the processing method of the groove 15 is as follows.
There is no particular limitation, and known processing techniques such as mechanical processing such as cutting and grinding and chemical processing such as etching can be adopted. Further, in FIG. 10, the grooves 15 are formed on both opposing surfaces other than the V-shaped rolling grooves of the inner ring 11 and the outer ring 12, but only one of the surfaces may be formed. Further, in FIG. 10, the direction in which the grooves are formed is parallel to the operation direction of the outer ring 12, but as shown in FIG.
It may have a certain angle with the operation direction of 2,
As shown in FIG. 12, the outer ring 12 may have different angles with respect to the operating direction.

FIG. 13 is a perspective view showing still another embodiment of the cross roller bearing. This cross roller bearing 10
Has a groove 15 formed on a surface of the retainer 13 facing the inner ring 11 and the outer ring 12 so as to be parallel to the operating direction of the outer ring 12. As described above, since the groove 15 is provided on the surface of the retainer 13 that faces the inner ring 11 and the outer ring 12, dust passes through the space between the inner ring 11, the outer ring 12, the retainer 13, and the roller 14. Are captured and held by this groove, so that dust generation can be effectively prevented. Although the groove 15 is formed in such a manner as to be parallel to the operation direction of the outer ring 12 in FIG. 13, it may have an angle with the operation direction of the outer ring 12 as shown in FIG. Alternatively, as shown in FIG. 12, the outer ring 12 may have different angles with respect to the operating direction.

In the cross roller bearing 10 shown in FIG. 10 to FIG.
1, a fluororesin film 22 is formed, or particles made of a fluororesin are impregnated in the electroless nickel film 21.

In the above description, the configuration is such that the fluororesin coating is formed only on the roller as the rolling element via the electroless nickel coating, or the electroless nickel coating is further impregnated with fluororesin particles. Although shown, it is also possible to adopt a configuration in which a similar coating is formed on the inner ring and the outer ring which are moving members.

(Third Embodiment: Ball Screw) Next, a case where the present invention is applied to a ball screw will be described. However, there is no restriction on the structure of the ball screw, and for example, the structure of the ball screw shown in FIG. 14 can be adopted. As shown in the figure, the ball screw 60 is one moving member, and a screw shaft 62 having a spiral screw groove 61 formed on an outer peripheral surface serving as a guide surface thereof, and the other moving member, A nut 65 in which a spiral screw groove 64 facing the screw groove 61 is formed on an inner peripheral surface 63 serving as its guide surface, and a rolling element interposed between the opposed screw grooves so as to freely roll. A plurality of balls 66 and a tubular circulation path 70 for circulating the balls 66 are provided.

It is preferable that at least one of the screw shaft 62, the nut 65 and the ball 66 is made of ceramic or the whole surface in terms of corrosion resistance. At this time, as the ceramic material, titanium nitride, titanium carbonitride, chromium nitride, or the like is excellent in adhesion and can be particularly preferably used. In the case of a ceramic coating, its thickness is 1
Desirably, it is 10 to 10 μm. As the film forming method, a known film forming technique such as a vacuum evaporation method, sputtering, ion plating, ion mixing, and CVD method can be adopted. In particular, when used in a highly corrosive environment, these members as a whole can be made of ceramics such as silicon nitride, silicon carbide, sialon, partially stabilized zirconia, and alumina.

The tube-type circulation path 70 is formed of a tube having a substantially U-shape in outer shape. And is fixed to the outer surface of the nut 65 with a stopper 73. Ball 66 rolling in a spiral ball rolling space
Is moved around the screw grooves 61 and 64 a plurality of times, and then is picked up at one end 71 of the tubular circulation path 70, passes through the inside of the tubular circulation path 70, and then is moved to the other end (not shown). ) To return to the ball rolling space in the nut 65 is repeated.

In the present invention, this ball screw 60
At least one of the screw shaft 62, the nut 65, and the ball 66 is characterized in that a film made of electroless nickel and a film made of a fluororesin are sequentially formed on the surface thereof. FIG. 15 is a cross-sectional view showing the film configuration. As shown, an electroless nickel film 80 is formed on the surface of the screw shaft 62 and the nut 65, and a fluororesin film 81 is formed thereon. I have. The fluororesin is not particularly limited, and is the same as the fluororesin used in the linear guide bearing and the cross roller bearing described above. In addition, the film forming method can be applied to the case of a linear guide bearing or a cross roller bearing. still,
If the fluororesin film 5 is thinner than 0.1 μm, there is a problem in lubrication life.

Further, a similar film may be formed on the surface of the ball 66. However, if the ball 66 is made of ceramics such as silicon nitride, silicon carbide, partially stabilized zirconia, and alumina, the required seizure resistance can be obtained without forming the electroless nickel film 80 and the fluororesin film 81. . In addition, ceramic balls also have an advantage that they have better corrosion resistance than steel balls.

Further, the tubular circulation path 70 is made of steel,
A similar coating may be formed on the inner wall surface, and the tubular circulation path 70 may be made of fluororesin.

The above-described electroless nickel film 80 is formed by electroless plating. By this electroless plating, fine cracks and voids (see FIG. 2) are naturally formed on the surface, and the adhesion to the fluororesin coating 81 is enhanced. Also,
If the electroless nickel coating 80 is thinner than 1 μm, the adhesion to the fluororesin coating 81 and the rust prevention provided by the electroless nickel-phosphorous coating 80 itself become insufficient.

The upper limit of the film thickness of both the electroless nickel film 80 and the fluororesin film 81 is appropriately set in consideration of the clearance from the ball 66. The film thickness is 1-10μ
m, preferably about 2 to 7 μm, and the thickness of the fluororesin coating 81 is 0.1 μm or more.

As described above, the electroless nickel coating 80 has cracks and voids. Although the electroless nickel film 80 has a rust-preventing effect on the film itself, a corrosive atmosphere or the like passes through cracks and holes to corrode the base material (stainless steel) of the screw shaft 62, the nut 65, and the ball 66. There is also. Therefore, in addition to the fluororesin coating 81,
It is more preferable to impregnate the cracks and pores of the electroless nickel coating 80 with particles of the fluororesin that forms the fluororesin coating 81 to close the cracks and pores. This impregnation can be performed in the same manner as in the case of the linear guide bearing and the cross roller bearing described above.

In the ball screw 60 described above, FIG.
As shown in (1), it is also a preferable embodiment to interpose a spacer ball 90 between the balls 66. The size of the spacer ball 90 is set slightly smaller than that of the ball 66. The spacer ball 90 is preferably made of a fluororesin or a polyimide resin, and a steel ball having an electroless nickel film and a fluororesin film formed on the surface in this order can also be suitably used. By using the spacer balls 90, the adjacent balls 66
The rotation of the spacer balls 90 is not hindered by each other. In particular, when the spacer balls 90 are made of a fluororesin or a polyimide resin, or steel balls on which an electroless nickel film and a fluorine resin film are formed, the spacer balls 90 The transfer of the lubricant (fluororesin or polyimide resin) can be expected, so that a longer life can be expected.

[0049]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which, of course, are not intended to limit the scope of the present invention. (Examples 1 to 7 and Comparative Examples 1 to 3) [Production of linear guide bearing] A linear guide bearing 1 having the structure shown in FIG.
Was prepared as a material shown in FIG. Here, the electroless nickel film 21 was coated with a thickness of 10 μm. Examples 1 and 2
The PTFE coating 22 was formed by dipping in a solution in which PTFE particles were dispersed, and then heat-treated at 300 ° C. for 3 hours to form a film having a thickness of 1 μm. On the other hand, in Examples 3 to 7, the PTFE coating 22 has a P particle diameter of 0.4 μm.
The TFE particles were immersed in a solution having a liquid temperature of 40 ° C. dispersed together with a binder at a temperature of 40 ° C. for 20 minutes, and then heat-treated at 300 ° C. for 3 hours to form a PTFE film having a thickness of 1 μm.
The particles were formed by impregnation. In Examples 5 to 7, the ball 4
A ball 41 made of silicon nitride (Si ₃ N ₄ ), partially stabilized zirconia (PSZ), and PTFE, and a PTFE film 22 formed on the surface via an electroless nickel film 21 and impregnated with PTFE particles Balls 42 were alternately arranged (see FIG. 3). However, in Example 7, the diameter of the ball 42 made of PTFE was slightly reduced. Further, in Comparative Example 1, the ball 4 was coated with a PTFE fired film, and in Comparative Examples 2 and 3, the ball 4 was coated with a silver coating.

[0050]

[Table 1]

[Dust Generation Test] The dust generation test was performed using the apparatus shown in FIG. The test linear guide bearing 100 is rotated by a motor 110 by a rotation introducing machine 111 with a magnetic fluid seal,
It is reciprocated via the shaft 112 and the metal band 113. With the reciprocating motion, the test linear guide bearing 10
Dust generated from 0 is sent to a laser light scattering type particle counter 114, and the number of dust particles is measured. The dust test apparatus is installed in a class 100 level clean bench. The number of particles scattered outside from each linear guide bearing was measured using this dust test apparatus. The test conditions are as follows.・ Atmosphere: Atmosphere, room temperature ・ Test linear guide bearing: Model number LU09 (Guide shaft width: 9m)
m, guide shaft length; 70 mm, slider width; 20 mm, slider length; 27 mm) ・ Preload: 19.6 N ・ Average speed: 10 mm / sec ・ Stroke: 10 mm

Table 1 also shows the test results. In Table 1, the amount of dust generated from each bearing was 100% of the amount of dust generated in Comparative Example 1.
And expressed as a relative value. It can be seen that the linear guide bearing of the example according to the present invention generates a very small amount of dust as compared with the linear guide bearing of the comparative example in which a PTFE baked film or a silver film without an electroless nickel film is formed.

[Corrosion Resistance Test] The corrosion resistance of each test bearing was evaluated using a test apparatus shown in FIG. In the corrosion resistance evaluation test, the test bearing 100 was housed in a sealed container 201 into which a 0.5N hydrochloric acid aqueous solution 200 was injected, and a beaker 202 having an open top was housed and held at a temperature of 55 ° C. for 100 hours by a thermostat 203. After that, the external appearance was visually observed. The evaluation results are also shown in Table 1. The linear guide bearing of the embodiment according to the present invention is a PT bearing without an electroless nickel coating.
It can be seen that the corrosion resistance is superior to the linear guide bearing of the comparative example in which the FE fired film and the silver film are treated. However, in Example 3, since the ceramic film was not formed on the guide shaft 2 and the slider 3, it was recognized that rust was generated on the surfaces of the guide shaft and the slider. It turned out to be inferior.

(Examples 8 to 15 and Comparative Examples 4 to 6) [Preparation of Cross Roller Bearing] The cross roller bearing 10 having the structure shown in FIG.
Were produced as materials shown in Table 2, respectively. Here, the electroless nickel film 21 was coated with a thickness of 10 μm. In Examples 8 and 9, the PTFE coating 22 was formed to a thickness of 1 μm by immersing in a solution in which PTFE particles were dispersed, and then performing a heat treatment at 300 ° C. for 3 hours. On the other hand, in Examples 11 to 15, the PTFE coating 22 has an average particle size of 0.4.
Liquid temperature of 4 μm PTFE particles dispersed with binder
It was immersed in a solution at 0 ° C. for 20 minutes and then heat-treated at 300 ° C. for 3 hours to form a 1 μm-thick PTFE film and to impregnate the PTFE particles. In the twelfth embodiment, a plurality of grooves are formed on the opposing surfaces of the inner race 11 and the outer race 12 other than the V-shaped rolling grooves so as to be parallel to the operating direction of the outer race 12 by cutting. In Examples 13 to 15, the rollers were made of silicon nitride (Si ₃ N ₄ ), partially stabilized zirconia (PSZ), a roller 51 made of PTFE, and a PTFE with an electroless nickel coating 21 on the surface.
The coatings 22 were formed, and the rollers 52 impregnated with the PTFE particles were alternately arranged (see FIG. 8). However, in Example 14, the diameter of the roller 52 made of PTFE was slightly reduced. Further, in Comparative Example 4, P
In Comparative Examples 5 and 6, the roller 14 was coated with a silver film.

[0055]

[Table 2]

[Dust Generation Test] The dust generation test was performed using the apparatus shown in FIG. In the test cross roller bearings 101 and 102, a table 130 is fixed to each outer ring, and a rotation introducer 132 with a magnetic fluid seal is
Shaft 133, metal band 134 and table 130
Is reciprocated through. The dust generated from the test cross roller bearings 101 and 102 due to the reciprocating motion is sent to a laser light scattering type particle counter 135, and the number of dust particles is measured. This dust test apparatus is installed in a class 100 level clean bench. Using this dust test apparatus, the number of particles scattered outside from each cross roller bearing was measured. The test conditions are as follows. -Atmosphere: Atmosphere, room temperature-Test bearing: Model number CRG04 (width: 24mm,
(Height: 12mm, length; 50mm) ・ Load: 19.6N ・ Average speed: 10mm / sec ・ Stroke: 25mm

Table 2 also shows the test results. In Table 2, the amount of dust generated from each bearing was 100% of the amount of dust generated in Comparative Example 4.
And expressed as a relative value. The solid lubricated cross roller bearing of the embodiment according to the present invention has a PT without an electroless nickel coating.
It can be seen that the amount of dust generation is extremely small as compared with the cross roller bearing of the comparative example in which the FE fired film and the silver film were formed.

[Corrosion Resistance Test] The corrosion resistance of each test bearing was evaluated using a test apparatus shown in FIG. In the corrosion resistance evaluation test, the test bearing 101 (102) is housed in a sealed container 201 into which a 0.5N hydrochloric acid aqueous solution 200 is injected, and a beaker 202 having an open top is housed in a thermostatic bath 203.
After maintaining the temperature at 55 ° C. for 100 hours, the external appearance was visually observed. Table 2 also shows the evaluation results. It can be seen that the cross roller bearing of the example according to the present invention has better corrosion resistance than the cross roller bearing of the comparative example in which a PTFE baked film or a silver film without an electroless nickel film is treated. However, in the tenth embodiment, the inner ring 11 and the outer ring 12
Since no ceramic coating was formed on the bearing, it was recognized that rust was generated on the surfaces of the inner ring and the outer ring, and it was found that the bearing as a whole had slightly poor corrosion resistance.

(Examples 16 to 20 and Comparative Examples 7 to 8) [Production of Ball Screw] The ball screw 60 shown in FIG.
Each component of the screw shaft 62, the nut 65, the ball 66, and the tube (circulation path) 70 was subjected to each coating treatment as shown in Table 3. In the table, the result of applying the electroless nickel coating and the PTFE coating is indicated by “○”, and the materials of the other coatings are indicated. The film thickness was 10 μm for the electroless nickel coating of the example, 0.3 μm for the PTFE coating, 0.5 μm for the silver coating of the comparative example, and 2-3 for the PTFE coating.
μm. As for the ball 66, an electroless nickel film and a PTFE film were formed only in Example 16, and no film was formed in other Examples.
And 20 used ceramic balls. Comparative Example 7
In Comparative Example 8, a ball on which a single film of silver or PTFE was formed was used. The spacer balls 90 (see FIG. 16) used in Examples 18, 19 and 20 were made of a fluororesin, and in Example 20, an electroless nickel film and a PTFE film were used. Then, the amount of dust generated in each test ball screw in a vacuum and the life of the bearing were measured.

[0060]

[Table 3]

[Dust Generation Test] For the measurement of the amount of dust generated in a vacuum, a test apparatus shown in FIG. 21 was used. The dust generation of the ball screw is evaluated by measuring the amount of dust generated when the nut 65 reciprocates up and down due to the rotation of the screw shaft 62 installed in the vertical direction.
40. At this time, the rotation of the ball screw is performed through the magnetic fluid
This was performed by the servomotor 142. The load was applied by a weight 144 fixed to a nut 65. The measurement was performed in a vacuum chamber 143 maintained in a vacuum. The test conditions are as follows.・ Test ball screw: shaft diameter 15mm, lead 10mm,
Stroke 300mm ・ Load: 29.4N ・ Rotational speed: 300rpm ・ Degree of vacuum: 1 × 10 ^-3 Pa or less

[Bearing Life Test] The test apparatus shown in FIG. 22 was used for measuring the life in a vacuum. The life evaluation of the ball screw is performed by reciprocating two nuts 65 with a load applied in the axial direction of the screw shaft 62 by a coil spring, and the total number of rotations of the screw shaft 62 until the torque sharply increases (total of forward and reverse rotations). Was evaluated. The torque of the ball screw was continuously measured throughout the test by a leaf spring 151 to which a strain gauge 150 was attached. The rotation was introduced by the AC servomotor 153 via the magnetic fluid seal unit 152. The measurement was performed in a vacuum chamber 154 maintained in a vacuum. The test conditions are as follows. -Test ball screw: shaft diameter 12 mm, lead 4 mm, stroke 160 mm-Load load: 29.4 N-Rotation speed: 600 rpm-Degree of vacuum: 1 × 10 ^-3 Pa or less

Table 3 shows the results of the above dust generation test and life test in vacuum. The results of the dust generation test are shown in terms of the relative amount of dust generated when Comparative Example 7 is set to 100. As is clear from Table 3, the ball screws of the examples according to the present invention are superior in both the amount of generated dust and the torque life as compared with the ball screw of the comparative example. Specifically, the ball screw of Comparative Example 7 in which silver, which is a conventional typical solid lubricating film, is formed has a dust generation amount 10 times that of the embodiment, and Comparative Example 8 in which only a PTFE film is formed. The ball screw has a dust generation amount of 100 in the embodiment.
It is 0 times, and the torque life is shorter by an order of magnitude. In particular, since the ball screw of Comparative Example 8 had no electroless nickel film, the adhesion between the film-forming component such as a screw shaft and the PTFE film was low.
It is considered that as a result of the TFE film peeling off from the film-formed component at an early stage, both the dust generation amount and the torque life are inferior. On the other hand, in the ball screw of the embodiment, due to the presence of the electroless nickel film, the adhesion between the PTFE film and the film-forming member is increased, the amount of dust generation is small, and the torque life can be extended. Further, it was confirmed that the use of the spacer balls prolonged the torque life.

[0064]

As described above, according to the linear motion device of the present invention, at least one of the guide surface or the rolling element of the moving member where the rolling friction or the sliding friction is generated is coated with fluorine through the electroless nickel coating. Since the resin coating is applied, the adhesion between the fluororesin coating and the coated surface is improved by the anchoring effect of the electroless nickel coating. Thereby,
Prevents the fluororesin's moving member from falling off the guide surface or rolling element, or excessive transfer to the guide surface or rolling element, and suppresses dust generation and maintains excellent lubrication for a long period of time. You. In addition, fine cracks and pores are usually present in the electroless nickel coating. At the same time as the formation of the fluororesin coating, the fluororesin particles enter the fine cracks and pores by the impregnation, and the fluorine The adhesion between the resin coating and the electroless nickel coating is further improved. Further, even after the fluororesin coating has disappeared due to abrasion, the impregnated fluororesin particles function as a lubricant, so that the lubrication life is extended as compared with the case of the fluororesin coating alone. Moreover,
Since the cracks and pores of the electroless nickel coating are blocked by fluororesin particles, the penetration of corrosive gas and water is prevented through these cracks and pores, improving corrosion resistance and preventing dust generation due to rust. can do. Further, by forming at least one of the guide surface or the whole of the moving member or the surface or the whole of the rolling element from ceramics, the corrosion resistance of the linear motion device against acid and alkali is further improved, and the generation of dust due to rust is further improved. It is prevented and can be used in highly corrosive environments. still,
When the electroless nickel-phosphorus film is provided, the film itself has a rust-preventive action, and the corrosion resistance is further improved.

[Brief description of the drawings]

FIG. 1 is a partially broken perspective view showing an example of a linear guide bearing which is a kind of a linear motion device of the present invention.

FIG. 2 is an enlarged sectional view of a ball of the linear guide bearing shown in FIG.

FIG. 3 is a partially broken perspective view showing another example of the linear guide bearing which is a kind of the linear motion device of the present invention.

FIG. 4 is a partially broken perspective view showing still another example of the linear guide bearing as a kind of the linear motion device of the present invention.

FIG. 5 is a partially broken perspective view showing still another example of the linear guide bearing as a kind of the linear motion device of the present invention.

FIG. 6 is a partially broken perspective view showing still another example of the linear guide bearing which is a kind of the linear motion device of the present invention.

FIG. 7 is a partially broken perspective view showing an example of a cross roller bearing which is a kind of the linear motion device of the present invention.

FIG. 8 is a partially broken perspective view showing another example of a cross roller bearing which is a kind of the linear motion device of the present invention.

FIG. 9 is a partially broken perspective view showing still another example of a cross roller bearing which is a kind of the linear motion device of the present invention.

FIG. 10 is a partially broken perspective view showing still another example of a cross roller bearing which is a kind of the linear motion device of the present invention.

FIG. 11 is a partially broken perspective view showing still another example of a cross roller bearing which is a kind of the linear motion device of the present invention.

FIG. 12 is a partially broken perspective view showing still another example of a cross roller bearing which is a kind of the linear motion device of the present invention.

FIG. 13 is a partially broken perspective view showing still another example of a cross roller bearing which is a kind of the linear motion device of the present invention.

FIG. 14 is a partial cross-sectional view showing an example of a ball screw which is a type of the linear motion device of the present invention.

FIG. 15 is a partial sectional view of the ball screw shown in FIG. 14;

FIG. 16 is a partial sectional view showing another example of a ball screw which is a kind of the linear motion device of the present invention.

FIG. 17 is a schematic configuration diagram of an apparatus used for a dust test in Examples 1 to 7.

FIG. 18 is a schematic configuration diagram of an apparatus used for a corrosion test in Examples 1 to 7.

FIG. 19 is a schematic configuration diagram of an apparatus used for a dust generation test in Examples 8 to 15.

FIG. 20 is a schematic configuration diagram of an apparatus used for a corrosion test in Examples 8 to 15.

FIG. 21 is a schematic configuration diagram of an apparatus used for a dust generation test in Examples 16 to 20.

FIG. 22 is a schematic configuration diagram of an apparatus used in a bearing life test in Examples 16 to 20.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Linear guide bearing 2 Guide shaft 3 Slider 4 Ball 10 Cross roller bearing 11 Inner ring 12 Outer ring 13 Cage 14 Roller 15 Groove 21 Electroless nickel coating 22 Fluororesin coating 60 Ball screw device 61 Screw groove 62 Screw shaft 64 Screw groove 65 Nut 66 Ball 80 Electroless nickel coating 81 PTFE coating 90 Spacer ball

Claims (3)

[Claims] 1. One moving member and the other moving member,
In a device that relatively linearly moves through rolling elements that are in contact with the respective guide surfaces, at least one of the two moving members or the rolling elements has a fluororesin coating formed on its surface via an electroless nickel coating. Linear motion device characterized by the following. 2. The one moving member and the other moving member,
In a device that relatively linearly moves through rolling elements that are in contact with the respective guide surfaces, at least one of the two moving members or the rolling elements has a film formed of a fluororesin formed on its surface through an electroless nickel film. A linear motion device, wherein the particles made of the fluororesin are impregnated in the electroless nickel film. 3. The linear motion device according to claim 1, wherein at least one of the guide surface or the whole of the two moving members or the surface or the whole of the rolling element is made of ceramics.