JP4748069B2 - Linear motion device - Google Patents

Description

  The present invention relates to a linear motion guide device, a linear motion device such as a ball screw.

As a lubricant for a linear motion device used under vacuum, a lubricating oil having a vapor pressure at 20 ° C. of 1 × 10 ⁻⁵ Pa or less and a grease based on the lubricating oil are generally used (Patent Document 1). , 2). In addition, there are those in which felt or porous resin is impregnated with the lubricating oil or grease as described above, or those which are mixed with the resin and solidified (see Patent Document 3). Furthermore, when a lubricating film made of a lubricant containing the above-described lubricating oil and fluororesin is formed on the sliding surface of the linear motion device (the raceway surface or the rolling surface of the rolling element) by oil plating. (See Patent Document 4).
JP 2001-152175 A JP 2001-72987 A JP 2001-59094 A JP 2005-36959 A

  However, when fluorine oil or hydrocarbon oil is used as the base oil for lubricating oil or grease in Patent Documents 1 and 2, although the load resistance and durability of the linear motion device are excellent, dust generation and outgassing are problems. There was a risk of becoming. Further, when fluorine oil or hydrocarbon oil is used in Patent Document 3, there is a possibility that the load resistance and durability of the linear motion device may be insufficient, and dust generation may be a problem.

Furthermore, when a lubricating film made of a lubricant containing two types of fluorine oil and fluororesin is formed in Patent Document 4, there is no problem with dust generation and outgassing properties, but load resistance and durability of the linear motion device. May become insufficient. Furthermore, when the lubricating film which consists of a lubricant containing hydrocarbon oil and a fluororesin is formed in patent document 4, there exists a possibility that the adhesiveness of the lubricating film with respect to the sliding surface of a linear motion apparatus may become inadequate.
Therefore, an object of the present invention is to solve the above-described problems of the prior art and to provide a linear motion device that is excellent in dust generation, outgassing, load resistance, and durability.

In order to solve the above problems, the present invention has the following configuration. That is, the linear motion device according to the first aspect of the present invention includes a guide member having a raceway surface and extending in the axial direction, a raceway surface facing the raceway surface of the guide member, and rolling between the raceway surfaces. And a movable member supported by the guide member so as to be linearly movable in the axial direction through rolling of a plurality of rolling elements arranged in a freely movable manner. At least one of the raceway surface of the member and the rolling surface of the rolling element is subjected to an oil plating process, and a hydrocarbon oil-based lubricating oil having a vapor pressure at 20 ° C. of 1 × 10 ⁻⁵ Pa or less and a molecular structure A lubricating film comprising a lubricant containing a synthetic oil containing at least one functional group among an epoxy group, an amino group, a carboxyl group, a hydroxyl group, a mercapto group, a sulfone group, and an ester group, and a fluororesin Form Together, characterized in that the following proportions of 18 wt% or more 36 wt% of the synthetic oil in the lubricant.

Since the synthetic oil has a high affinity for the material (metal or the like) constituting the raceway surface or rolling surface due to the action of the functional group, a lubricating film that adheres firmly to the raceway surface or rolling surface is formed. As a result, excellent durability, low dust generation, and low outgas are realized by the action of hydrocarbon oil-based lubricating oil and fluororesin (impregnated with lubricating oil) in the firmly adhered lubricating film.

The ratio of the synthetic oil in the lubricant needs to be 18% by mass or more and 36% by mass or less. When the amount is less than 18% by mass, the amount of the lubricating film adhering to the raceway surface and the rolling surface decreases, and as a result, the amount of hydrocarbon oil-based lubricating oil contributing to durability decreases. There is a risk that the durability of the resin becomes insufficient. On the other hand, even 36 mass% excess, it is hardly amount of the lubricating film to adhere to the raceway surfaces and the rolling surface increases, the linear motion device rather for the proportion of the synthetic oil lubricant is not high is too much Durability may be insufficient.

The lower the vapor pressure at 20 ° C. of the hydrocarbon oil-based lubricating oil, the smaller the outgas and the better. When the vapor pressure at 20 ° C. exceeds 1 × 10 ⁻⁵ Pa, the low outgassing property may be impaired.
Here, the oil plating process is a process for attaching a thin film of lubricant to the raceway surface of the guide member, the raceway surface of the movable member, or the rolling surface of the rolling element. For example, as will be described later, the lubricating film according to the present invention can be formed by attaching a diluted lubricant to the rolling surface and removing the diluted solvent by heat treatment. The lubricating film formed by such an oil plating process is unlikely to generate outgas even under high vacuum, and hardly contaminates the surrounding environment.

The linear motion device according to claim 2 of the present invention is the linear motion device according to claim 1, wherein the ratio of the fluororesin in the lubricant is 1% by mass or more and 20% by mass or less. And
The fine and amorphous fluororesin is impregnated with lubricating oil and swells in a gel form. As a result, the retention of the lubricating oil on the raceway surface and the rolling surface is improved, and the lubrication life is improved. If the ratio of the fluororesin in the lubricant is small, the fluororesin is less likely to be evenly dispersed in the lubricating film, and the effect of improving the durability of the linear motion device may be poor. Is preferably 1% by mass or more, and more preferably 5% by mass or more. However, if the ratio of the fluororesin in the lubricant is too large, the fluororesin is insufficiently swollen, and the fluororesin that is insufficiently swollen when the linear motion device is driven may hinder smooth rolling of the rolling element. There is. Therefore, the ratio of the fluororesin in the lubricant is preferably 20% by mass or less.

A linear motion device according to a third aspect of the present invention is the linear motion device according to the first or second aspect, wherein a diamond-like carbon film is formed under the lubricating film.
Since the diamond-like carbon coating forms extremely fine irregularities on the raceway surface and the rolling surface (porous structure), the retention of the lubricant is improved and the durability of the linear motion device is improved.

Furthermore, the linear motion device according to claim 4 of the present invention is the linear motion device according to any one of claims 1 to 3, wherein the hydrocarbon-based lubricating oil is an alkylated cyclohexane having an average molecular weight of 2000 or less. It is characterized by being pentane.
Lubricating oils having a low average molecular weight are excellent in fluidity and therefore have high lubricity. On the other hand, since the vapor pressure is high, it tends to volatilize under vacuum. However, alkylated cyclopentane is preferable because it has a low vapor pressure due to the action of a cyclic molecular structure even when the molecular weight is small, and highly purified alkylated cyclopentane is particularly preferable. Among such alkylated cyclopentanes, those having an average molecular weight of 2000 or less and having a vapor pressure of 1 × 10 ⁻⁵ Pa or less at 20 ° C. have excellent fluidity even under high vacuum. is doing. In addition, since the evaporation rate is low, volatilization of the lubricating oil is suppressed over a long period. As a result, the linear motion device has a long life.

Furthermore, the linear motion device according to claim 5 of the present invention is the linear motion device according to any one of claims 1 to 4, wherein the fluororesin has a particle size of 10 μm or less and a density of 3 g / cm ^3. It is characterized by the following.
As described above, the fine and amorphous fluororesin is impregnated with the lubricating oil and swells in a gel form. As a result, the retention of the lubricating oil on the raceway surface and the rolling surface is improved, and the lubrication life is improved. However, if the particle size of the fluororesin is large, it may act as a foreign substance on the linear motion device, so that stable driving may be hindered, and abnormal fluctuation may occur in the dynamic friction force. Moreover, when the density of a fluororesin is large, it will become crystalline and it will become difficult to impregnate lubricating oil, and there exists a possibility that lubricity may fall.

When the particle size of the fluororesin is 10 μm or less and the density is 3 g / cm ³ or less, the driving stability, slidability, and lubricity of the linear motion device are excellent. In addition, when a fluororesin is scale-like, let the maximum length be a particle size.
Further, a linear motion device according to a sixth aspect of the present invention is the linear motion device according to any one of the first to fifth aspects, wherein at least one of the guide member, the movable member, and the rolling element is provided. It is characterized by comprising stainless steel.
With such a configuration, the linear motion device has excellent corrosion resistance even under vacuum where rust prevention is difficult.

Furthermore, the linear motion device according to claim 7 of the present invention is the linear motion device according to any one of claims 1 to 5, wherein at least one of the guide member, the movable member, and the rolling element is provided. It is characterized by comprising a non-magnetic material.
With such a configuration, the linear motion device has excellent corrosion resistance even under vacuum where rust prevention is difficult. Moreover, it can be used suitably also for a semiconductor manufacturing apparatus, and it can be set as the semiconductor manufacturing apparatus suitable for performing microfabrication. Furthermore, magnetization is suppressed when used for a linear motor.

  The linear motion device of the present invention is excellent in dust generation, outgassing, load resistance, and durability.

An embodiment of a linear motion device according to the present invention will be described in detail with reference to the drawings.
[First embodiment]
FIG. 1 is a perspective view showing a linear motion guide device that is an embodiment of the linear motion device according to the present invention, and FIG. 2 is a front view of the linear motion guide device of FIG. The end cap is omitted in the figure).

On a guide rail 1 having a substantially square cross section extending in the axial direction, a slider 2 having a substantially U-shaped cross section is mounted so as to be capable of relative linear movement in the axial direction. The guide rail 1 corresponds to a guide member that is a constituent element of the present invention, and the slider 2 corresponds to a movable member that is a constituent element of the present invention.
Rolling element rolling grooves 10 and 10 each formed of a concave groove having a substantially arc-shaped cross section extending in the axial direction are formed at a ridge line portion where the upper surface of the guide rail 1 and both side surfaces 1a and 1a intersect. Rolling element rolling grooves 10 and 10 each having a substantially semicircular cross section extending in the axial direction are formed at intermediate positions of both side surfaces 1a and 1a of the guide rail 1. The inner surface of the rolling element rolling groove 10 forms a raceway surface on which a rolling element 3 described later rolls.

The slider 2 includes a slider body 2A and end caps 2B and 2B that are detachably attached to both ends in the axial direction. Further, both ends of the slider 2 (end surfaces of the end caps 2B). ) Are provided with side seals 5 and 5 for sealing the opening of the gap between the guide rail 1 and the slider 2.
Furthermore, rolling element rolling grooves 11 and 11 having a substantially semicircular cross section facing the rolling element rolling grooves 10 and 10 of the guide rail 1 are formed at the corners of the inner surfaces of both sleeve portions 6 and 6 of the slider body 2A. Formed at the center of the inner surface of the sleeves 6 and 6 are rolling element rolling grooves 11 and 11 having a substantially semicircular cross section facing the rolling element rolling grooves 10 and 10 of the guide rail 1. Yes. The inner surface of the rolling element rolling groove 11 forms a raceway surface on which a rolling element 3 described later rolls.

  The rolling element rolling grooves 10, 10, 10, 10 of the guide rail 1 and the rolling element rolling grooves 11, 11, 11, 11 of both sleeve portions 6, 6 have a substantially circular cross section. 14, 14, 14, and 14 are formed, and these rolling element rolling paths 14 extend in the axial direction. The number of rolling element rolling grooves 10 and 11 provided in the guide rail 1 and the slider 2 is not limited to two rows on one side, and may be one row on one side or three rows or more, for example.

Furthermore, the slider 2 is formed of a through-hole having a circular cross-section that penetrates in the axial direction in parallel to the rolling element rolling path 14 at the upper and lower portions of the thick portions of the sleeve portions 6 and 6 of the slider body 2A. A moving body return path 13, 13, 13, 13 is provided.
On the other hand, although not shown, the end caps 2B and 2B having a substantially U-shaped cross section have a rolling element rolling path 14 and a rolling element return path parallel to the rolling element rolling path 14 on the contact surface (back surface) with the slider body 2A. The rolling element rolling path 14, the rolling element return path 13, and the curved paths at both ends form a substantially annular rolling element circulation path. . In this rolling element circulation path, a large number of rolling elements (balls) 3 made of, for example, steel balls are loaded so as to freely roll.

When the slider 2 assembled to the guide rail 1 is moved in the axial direction along the guide rail 1, the rolling element 3 loaded in the rolling element rolling path 14 rolls in the rolling element rolling path 14. It moves in the same direction as the slider 2 with respect to the guide rail 1 while moving. When the rolling element 3 reaches one end of the rolling element rolling path 14, it is scooped up from the rolling element rolling path 14 by the tongue provided in the end cap 2B and sent to the curved path.
The rolling element 3 having entered the curved path makes a U-turn and is introduced into the rolling element return path 13, and reaches the opposite curved path through the rolling element return path 13. Here, the U-turn is performed again to return to the rolling element rolling path 14, and the circulation in the rolling element circulation path is repeated infinitely.

At least one of the inner surface of the rolling element rolling groove 10, the inner surface of the rolling element rolling groove 11, and the surface (rolling surface) of the rolling element 3 of such a linear motion guide device is provided with a lubricating film ( (Not shown) is formed by an oil plating process. This lubricant contains a hydrocarbon oil-based lubricant having a vapor pressure of 1 × 10 ⁻⁵ Pa or less at 20 ° C., a lubricant containing a functional group in the molecular structure, and a fluororesin. The ratio of the lubricating oil containing a functional group in the molecular structure in the lubricant is 18% by mass or more and 36% by mass or less. In addition, it is preferable that the ratio of the fluororesin in a lubricant shall be 1 mass% or more and 20 mass% or less.

  By such a lubricating film, the lubricant is always supplied to the raceway surface on which the rolling element 3 rolls, and direct contact between the raceway surface and the rolling surface is suppressed. Excess lubricating oil is absorbed and trapped in the fluororesin. Furthermore, a lubricating film that adheres firmly to the raceway surface and the rolling surface is formed by the lubricating oil containing a functional group in the molecular structure. As a result, low dust generation and low outgas are realized even under high vacuum, and excellent lubricity, load resistance, and durability can be obtained.

Here, an example of the oil plating process is shown. Diluting a hydrocarbon oil-based lubricating oil having a vapor pressure of 1 × 10 ⁻⁵ Pa or less at 20 ° C., a lubricating oil containing a functional group in the molecular structure, and a fluororesin with a solvent such as hexane, and rolling element rolling Thinly attached to the inner surface of the groove 10, the inner surface of the rolling element rolling groove 11, and the surface of the rolling element 3. Examples of the adhesion method include application, spraying, and immersion. Then, a lubricant film made of a lubricant is formed by performing a heat treatment to volatilize and bake the solvent.

  The temperature of heat processing needs to be more than the boiling point of a solvent. However, if the temperature is too high, the accuracy of the linear motion guide device may be reduced. Therefore, the annealing temperature of the base material constituting the guide rail 1, the slider 2, and the rolling element 3 is preferably equal to or lower. When the solvent is hexane, heating for about 30 minutes at a temperature of 60 ° C. or more is sufficient. The lubricating film baked in this way is firmly attached to the metal surface by the action of lubricating oil containing functional groups in the molecular structure.

The type of hydrocarbon oil-based lubricating oil having a vapor pressure at 20 ° C. of 1 × 10 ⁻⁵ Pa or less is not particularly limited, but alkylated cyclopentane is preferable, and alkylated cyclopentane having an average molecular weight of 2000 or less. Is particularly preferred. In addition, as lubricating oils containing functional groups in the molecular structure, synthetic groups containing epoxy groups, amino groups, carboxyl groups, hydroxyl groups, mercapto groups, sulfone groups, ester groups, etc., which are functional groups with high affinity for metals. Oil is preferred. Also for this synthetic oil, the vapor pressure at 20 ° C. is preferably 1 × 10 ⁻⁵ Pa or less.
Furthermore, as the fluororesin, polytetrafluoroethylene (PTFE), tetrafluoroethylene perfluorovinyl ether copolymer (PFA), fluorinated ethylene propylene copolymer (FEP) and the like can be suitably used, but the particle size is It is preferable that the density is 10 μm or less and the density is 3 g / cm ³ or less.

  Furthermore, it is preferable that at least one of the guide rail 1, the slider 2, and the rolling element 3 is made of stainless steel. Examples of the stainless steel include SUS440C, which is martensitic stainless steel, and SUS316, SUS304, which is austenitic stainless steel. Moreover, you may use a sintered metal (MIM) as stainless steel. Furthermore, if the rolling element return path 13 and the curved path for circulating the rolling element 3 are also made of stainless steel and the lubricating film is formed by oil plating, the entire rolling element circulation path where the rolling element 3 rolls is formed. Since the lubricity is improved, the durability of the linear motion guide device is further improved.

  Furthermore, at least one of the guide rail 1, the slider 2, and the rolling element 3 may be made of a nonmagnetic material. As the nonmagnetic material, for example, a titanium alloy is used, and a material subjected to surface hardening treatment is preferable. Further, ceramics such as silicon nitride, alumina, and partially stabilized zirconia may be used. The guide rail 1, the slider 2, and the rolling element 3 may all be made of a nonmagnetic material. For example, from the viewpoint of durability and high speed, only the rolling element 3 is made of a nonmagnetic material, and the others are stainless steel. You may comprise steel. By constituting only the rolling elements from different materials, an effect of suppressing wear is obtained, and since the specific gravity is light, the collision energy of the rolling elements 3 is reduced and the high speed is improved.

  A diamond-like carbon film may be formed below the lubricating film. Further, a spacer may be interposed between the rolling elements 3. If it does so, the competition and abrasion of the rolling elements 3 will be suppressed, and the lifetime of a linear motion guide apparatus will improve. As the spacer, a ball having a diameter smaller than the rolling element 3 by 10 to 30 μm is preferable. The number of spacers used varies depending on the usage conditions of the linear motion guide device, but one spacer is preferable for one or two rolling elements 3.

[Second Embodiment]
FIG. 3 is a cross-sectional view of a ball screw which is an embodiment of the linear motion device according to the present invention. The ball screw has a screw shaft 21 having a spiral thread groove 21a having an arcuate cross section on the outer peripheral surface and a spiral screw groove 22a having an arc cross section facing the screw groove 21a of the screw shaft 21 on the inner peripheral surface. Rolling into a spiral ball rolling path 26 having a substantially circular cross section formed by a cylindrical nut 22 that is screwed onto the female screw shaft 21, a screw groove 21 a of the screw shaft 21, and a screw groove 22 a of the nut 22. And a large number of balls 23 loaded freely. The screw shaft 21 corresponds to a guide member that is a constituent element of the present invention, and the nut 22 corresponds to a movable member that is a constituent element of the present invention. Further, the inner surfaces of the thread grooves 21a and 22a form a raceway surface on which the ball 23 rolls.

  The nut 22 is provided with a return tube 27 bent in a substantially U-shape so that the ball 23 in the ball rolling path 26 is circulated through the return tube 27. That is, the ball 23 rolling in the ball rolling path 26 moves in the ball rolling path 26 and rotates around the screw shaft 21 a plurality of times, and then the return tube 27 of one end of the ball rolling path 26 is Scooped up at one end. The scooped ball 23 passes through the return tube 27 and is returned from the other end of the return tube 27 to the other end of the ball rolling path 26.

Then, the nut 22 screwed into the screw shaft 21 via the ball 23 and the screw shaft 21 perform relative rotational movement through the rolling of the many balls 23, whereby the screw shaft 21 and the nut 22 are moved. And move relative to each other in the axial direction.
At least one of the inner surface of the screw groove 21a of the ball screw, the inner surface of the screw groove 22a, and the surface (rolling surface) of the ball 23 is lubricated with a lubricant film (not shown) made of a lubricant. It is formed by. This lubricant contains a hydrocarbon oil-based lubricant having a vapor pressure of 1 × 10 ⁻⁵ Pa or less at 20 ° C., a lubricant containing a functional group in the molecular structure, and a fluororesin. The ratio of the lubricating oil containing a functional group in the molecular structure in the lubricant is 18% by mass or more and 36% by mass or less. In addition, it is preferable that the ratio of the fluororesin in a lubricant shall be 1 mass% or more and 20 mass% or less.

  With such a lubricating film, the lubricant is always supplied to the raceway surface on which the ball 23 rolls, and direct contact between the raceway surface and the rolling surface is suppressed. Excess lubricating oil is absorbed and trapped in the fluororesin. Furthermore, a lubricating film that adheres firmly to the raceway surface and the rolling surface is formed by the lubricating oil containing a functional group in the molecular structure. As a result, low dust generation and low outgas are realized even under high vacuum, and excellent lubricity, load resistance, and durability can be obtained.

For oil plating treatment contents, hydrocarbon oil-based lubricants with a vapor pressure of 1 × 10 ^-5 Pa or less at 20 ° C., lubricants containing a functional group in the molecular structure, and fluororesin, the first implementation Since it is the same as the form, the description thereof is omitted. Moreover, since the guide rail 1, the slider 2, and the base material of the rolling element 3 are the same as those in the first embodiment, the description thereof is omitted. Further, as in the first embodiment, a diamond-like carbon film may be formed in the lower layer of the lubricating film, or a spacer may be interposed between the balls 23.

〔Example〕
Hereinafter, the present invention will be described with reference to more specific examples. Durability and sliding characteristics of the linear motion guide device having substantially the same configuration as the linear motion guide device of the first embodiment described above were evaluated.
In the linear motion guide device, the guide rail and slider are made of stainless steel equivalent to SUS440C, the rolling element (diameter 2.778 mm) is made of SUS440C, and the end cap (curved path) is made of stainless steel equivalent to SUS316. Is given.

A lubricating film is formed by oil plating on the raceway surface of the guide rail, the raceway surface of the slider, the rolling surface of the rolling element, the inner surface of the rolling element return path, and the curved path. As a hydrocarbon oil-based lubricating oil having a vapor pressure at 20 ° C. of 1 × 10 ⁻⁵ Pa or less, alkylated cyclopentane (Nye Synthetic Oil 2001 manufactured by Nye Lubricants) is used, and a functional group is included in the molecular structure. A synthetic oil containing an ester group was used as the lubricating oil, and PTFE powder (DuPont dry film RA) was used as the fluororesin. The amount ratio of the alkylated cyclopentane, the synthetic oil containing an ester group, and the PTFE powder is as shown in Table 1.

  These were diluted with hexane to a concentration of 5% by mass, and each of the aforementioned parts was immersed in the obtained diluted solution. And each above-mentioned component was picked out from the dilution liquid, and it heated for 30 minutes at 80 degreeC under pressure reduction of 0.1 Pa, the hexane was evaporated, and the lubricating film was formed. Since hexane is a solvent for uniformly plating the two oils, the dilution concentration is not limited to the above numerical values.

The durability was evaluated as follows. A linear motion guide is applied at a speed of 0.5 m / s under a reduced pressure of 3 × 10 ⁻⁴ Pa with a preload applied so that the maximum contact surface pressure between the rolling element and the raceway surface becomes 1.5 GPa. The apparatus was driven, and the dynamic frictional force of the slider and the torque of the nut at that time were measured. The lifetime was determined when the dynamic friction force or the torque of the nut doubled compared to when the drive was started.

The results are shown in FIG. In addition, the numerical value of the lifetime shown in the graph of FIG. 4 is a relative value where the lifetime is 1 when the travel distance of the slider or the nut until reaching the lifetime is 100 km. For example, when the lifetime is 10, the travel distance of the slider or nut until the lifetime is reached is 1000 km.
From the graph of FIG. 4, it can be seen that the lifetime is long when the content of the lubricating oil containing a functional group in the molecular structure is 18 mass% or more and 36 mass% or less.

  Next, a method for evaluating sliding characteristics will be described. Except that the amount ratio of PTFE powder in the lubricant is different, a linear motion guide device having the same configuration as that of the linear motion guide device No. E used for durability evaluation was used, and the slider was moved at a speed of 0.5 m / The sliding characteristics when running at s were evaluated. The quantity ratio of the PTFE powder in the lubricant is as shown in Table 2, the quantity ratio of the synthetic oil containing ester groups is fixed at 18% by mass, and the alkylated cyclopentane is mixed according to the quantity ratio of the PTFE powder. The amount ratio was increased or decreased.

  Table 2 shows the evaluation results of the sliding characteristics. The sliding characteristic was determined by whether or not a problem occurred in the function of the device when the linear motion guide device was driven. From the results of Table 2, if the amount of PTFE powder is too large, the inner surface of the guide rail raceway surface, the slider raceway surface, the rolling element rolling surface, the rolling body return path and the inner surface of the curved path on which the lubricating film is formed. Since the frictional force increases and the sliding characteristics deteriorate, the rolling element clogging occurs intermittently in the rolling element circulation path consisting of the rolling element rolling path, the rolling element return path, and the curved path. It turns out that a problem arises. Therefore, the amount of PTFE powder is preferably 20% by mass or less.

  However, although not shown in Table 2, if the amount of PTFE powder is 0% by mass, there is a problem in durability of the linear motion guide device. If the amount of PTFE powder is less than 1% by mass, the PTFE powder is less likely to be uniformly dispersed in the lubricating film, and the effect of improving the durability of the linear motion guide device may be poor. The ratio is preferably 1% by mass or more, and more preferably 5% by mass or more.

  Next, an outgassing evaluation method will be described. The outgas property was evaluated using an outgas rate evaluation test apparatus as shown in FIG. A sample chamber 92 in which the sample 90 is accommodated communicates with an analysis chamber 91 to which a turbo molecular pump 96 and a rotary pump 97 are connected by an orifice 93 having a circular cross section with a diameter R of 2 to 3 mm. When the gas in the analysis chamber 91 is sucked by the turbo molecular pump 96 and the rotary pump 97, the pressure in the analysis chamber 91 becomes lower than that in the sample chamber 92, so that the gas in the sample chamber 92 passes through the orifice 93 and is analyzed. It flows into the chamber 91. In addition, a quadrupole mass spectrometer 98 is also installed in the analysis chamber 91 so that the type of gas generated in the sample chamber 92 and flowing into the analysis chamber 91 can be analyzed.

  In a state where gas flows from the sample chamber 92 to the analysis chamber 91, the atmospheric pressure is measured by the ion gauges 94 and 95 installed in the sample chamber 92 and the analysis chamber 91, respectively, and the outgas generation rate (outgas velocity) from the sample 90 is measured. ). The outgas speed is obtained by the equation Qb = C (P2-P1) -Qc. Here, each value in the formula is as follows.

Qb: Outgas speed of sample (Pa · m ³ / s)
Qc: Outgas speed of chamber (Pa · m ³ / s)
C: Orifice conductance (constant) (m ³ / s)
P1: Analytical chamber pressure (Pa)
P2: Sample chamber chamber pressure (Pa)

  The outgas velocity Qc of the chamber is an outgas velocity measured when the sample 90 is not accommodated in the sample chamber 92, and is obtained by the equation Qc = C (P2′−P1 ′) based on the measured value of the atmospheric pressure. It is. Here, P1 'and P2' are an analysis chamber chamber pressure and a sample chamber chamber pressure measured when the sample 90 is not accommodated, respectively.

The results of the outgassing evaluation at each temperature are shown in the graph of FIG. The evaluated samples are as follows. First, in the examples, a metal piece in which a lubricant film made of the lubricant used in the above-described apparatus No. E was formed by oil plating was used as a sample. In Comparative Example A, a metal piece in which a lubricating film made of a lubricant containing fluoro oil and fluoro resin was formed by oil plating was used as a sample. Fluorine-based high performance oil S-200 manufactured by Daikin Industries, Ltd. was used as the fluorine oil, and Krytox FSH manufactured by DuPont was used as the fluorine resin. Further, in Comparative Example B, a metal piece coated with fluorine grease (Demkin L200 manufactured by Daikin Industries, Ltd.) was used as a sample. Furthermore, “BG” in FIG. 6 is a background, and is a result when an outgassing evaluation is performed without using a sample.
As can be seen from FIG. 6, the example provided with the lubricating film according to the present invention had better outgassing properties than Comparative Examples A and B.

It is a perspective view which shows the structure of the linear motion guide apparatus which is one Embodiment of the linear motion apparatus which concerns on this invention. It is the front view which looked at the linear motion guide apparatus of FIG. 1 from the axial direction. It is sectional drawing which shows the structure of the ball screw which is one Embodiment of the linear motion apparatus which concerns on this invention. It is a graph which shows the evaluation result of durability of a linear guideway. It is a figure explaining the structure of an outgas velocity evaluation test apparatus. It is a graph which shows the evaluation result of outgas property.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Guide rail 2 Slider 2A Slider main body 2B End cap 3 Rolling body 10 Rolling body rolling groove 11 Rolling body rolling groove 21 Screw shaft 21a Screw groove 22 Nut 22a Screw groove 23 Ball

Claims (7)

Via a rolling of a plurality of rolling elements having a raceway surface and extending in the axial direction, and a raceway surface facing the raceway surface of the guide member and arranged to be freely rollable between the raceway surfaces. In a linear motion device comprising a movable member supported by the guide member so as to be linearly movable in the axial direction,
At least one of the raceway surface of the guide member, the raceway surface of the movable member, and the rolling surface of the rolling element is a hydrocarbon having a vapor pressure at 20 ° C. of 1 × 10 ⁻⁵ Pa or less by oil plating treatment. An oil-based lubricating oil, a synthetic oil containing at least one functional group among epoxy group, amino group, carboxyl group, hydroxyl group, mercapto group, sulfone group, and ester group in the molecular structure; and a fluororesin A linear motion device characterized by forming a lubricating film made of a contained lubricant and having a ratio of the synthetic oil in the lubricant of 18% by mass or more and 36% by mass or less.   The linear motion device according to claim 1, wherein a ratio of the fluororesin in the lubricant is 1% by mass or more and 20% by mass or less.   The linear motion device according to claim 1, wherein a diamond-like carbon film is formed under the lubricating film.   The linear motion apparatus according to any one of claims 1 to 3, wherein the hydrocarbon oil-based lubricating oil is an alkylated cyclopentane having an average molecular weight of 2000 or less. The linear motion device according to any one of claims 1 to 4, wherein the fluororesin has a particle size of 10 µm or less and a density of 3 g / cm ³ or less.   The linear motion device according to any one of claims 1 to 5, wherein at least one of the guide member, the movable member, and the rolling element is made of stainless steel.   The linear motion device according to any one of claims 1 to 5, wherein at least one of the guide member, the movable member, and the rolling element is made of a nonmagnetic material.

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