Rolling bearing and actuator

Abstract

To provide: a rolling bearing used in a high cleanliness environment in which, while grease used as a lubricating oil can be prevented from decomposing, an amount of dust produced can be reduced not only before decontamination by hydrogen peroxide, etc. but also after the decontamination; and an actuator equipped with the same.SOLUTION: A rolling bearing 1 has grease enclosed therein including a base oil and a thickener. The base oil contains a fluorine oil. The thickener contains a polytetrafluoroethylene resin powder. The worked penetration of the grease is 200 or more and 295 or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rolling bearing and an actuator equipped with the rolling bearing. [Background technology]

[0002] Conventionally, rolling bearings have been widely used in the fields of machinery, vehicles, etc. In particular, rolling bearings lubricated with fluorine grease based on fluorine oil are used to support the rotating parts of rotating equipment used in clean environments, vacuum environments, and high-temperature environments. Specifically, lubrication is achieved by filling the internal space of the rolling bearing with fluorine grease.

[0003] It is a well-known fact that particles are generated from the lubricant in the rolling bearings in actuators when the device is operated. Therefore, when actuators are used in the various fields mentioned above, there is a demand for reducing the amount of particles generated from the rolling bearings.

[0004] In particular, in various fields such as food manufacturing equipment, electronics industry, chemical industry, and medicine, a cleaner environment is required. For example, devices used in the field of regenerative medicine include cell culture devices and cell layering devices for manipulating cells. Since cells may be adversely affected by contamination with substances other than cells, such as particles generated from lubricants, in the field of regenerative medicine, the environment surrounding the device must be extremely clean. Therefore, devices used in the field of regenerative medicine are subjected to a decontamination process in which they are exposed to hydrogen peroxide or the like in order to reduce the number of bacteria to a certain level.

[0005] Incidentally, Patent Document 1 discloses a rolling bearing filled with a grease composition containing specific PTFE (polytetrafluoroethylene) fine particles in an amount of 30% by mass to 90% by mass of the total amount of the grease composition and using fluorinated oil as a base oil. The above rolling bearing has a reduced content of perfluorooctanoic acid (PFOA) compounds that have an adverse effect on the global environment, and can reduce volatilization and scattering that accompanies the use of the rolling bearing. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2023-012700 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the rolling bearing described in the above Patent Document 1 does not take into consideration the above-mentioned decontamination. For example, when a rolling bearing filled with grease is exposed to hydrogen peroxide or the like, the grease may deteriorate and may not be able to maintain the desired lubrication. Furthermore, the deterioration of the grease significantly increases the amount of dust generated. In conventional rolling bearings, the deterioration of the grease cannot be prevented, particularly after the decontamination process, and the amount of dust generated cannot be sufficiently reduced.

[0008] The present invention has been made in consideration of these problems, and has an object to provide a rolling bearing that can be used in a high-clean environment, can prevent deterioration of grease used as a lubricant, and can reduce the amount of dust generated even when exposed to hydrogen peroxide, etc., and an actuator equipped with this rolling bearing. [Means for solving the problem]

[0009] The above object of the present invention is achieved by the rolling bearing having the following configuration (1).

[0010] (1) A rolling bearing packed with grease containing a base oil and a thickener, The base oil contains a fluorinated oil, The thickener contains polytetrafluoroethylene resin powder, A rolling bearing, characterized in that the grease has a worked penetration of 200 or more and 295 or less.

[0011] Further, preferred embodiments of the present invention relating to the rolling bearing relate to the following (2) to (8). (2) The base oil has a kinetic viscosity of 10 mm at 40°C. 2 / s or more 200mm 2 / s or less.

[0012] (3) The rolling bearing according to (1) or (2), wherein the fluorinated oil is perfluoropolyether.

[0013] (4) The rolling bearing according to any one of (1) to (3), wherein the content of the thickener relative to the total mass of the grease is 30 mass % or more and 50 mass % or less.

[0014] (5) The rolling bearing according to any one of (1) to (4), wherein the specific gravity of the grease is 1.50 or more.

[0015] (6) The rolling bearing according to any one of (1) to (5), wherein the grease has an oxidation stability of 10 kPa or less.

[0016] (7) The rolling bearing according to any one of (1) to (6), which is used in an environment exposed to an atmosphere containing at least one of hydrogen peroxide and peracetic acid.

[0017] (8) The rolling bearing according to any one of (1) to (7), which is included in a device used in the field of regenerative medicine.

[0018] The above object of the present invention is achieved by the following configuration (9) relating to the actuator. (9) An actuator comprising: a rolling bearing according to any one of (1) to (8); a ball screw supported by the rolling bearing; and a linear guide that guides the direction of movement of a member moved by the ball screw.

[0019] Further, preferred embodiments of the present invention relating to the actuator relate to the following items (10) to (11). (10) The actuator according to (9), wherein a low-temperature chromium fluoride plating film is formed on a surface of the ball screw and a surface of the linear guide.

[0020] (11) The actuator according to (9) or (10), which is used in an environment exposed to an atmosphere containing at least one of hydrogen peroxide and peracetic acid, and which does not have a cover that covers the rolling bearing, the ball screw, and the linear guide. Effect of the Invention

[0021] The rolling bearing of the present invention specifies the base oil and thickener of the grease to be enclosed, and appropriately controls the worked penetration of the grease, thereby making it possible to prevent deterioration of the grease and to maintain excellent low dust generation properties even after the rolling bearing is exposed to hydrogen peroxide, etc.

[0022] Furthermore, since the actuator of the present invention is equipped with the above-mentioned rolling bearing, it is possible to suppress deterioration of actuator performance due to grease deterioration or particles generated from the grease, etc., and to achieve long-term operation at low cost. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a rolling bearing according to this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The present inventors have conducted extensive research into technology for realizing low dust generation characteristics for actuators used in environments requiring high cleanliness (hereinafter referred to as clean environments) and rolling bearings provided within the actuators. As a result, they have found that by strictly adjusting the material and physical properties of the grease used as a lubricant, it is possible to prevent deterioration of the grease, particularly when the grease is placed in an environment exposed to hydrogen peroxide, and thereby the low dust generation characteristics of the grease can be maintained. The present invention is based on these findings.

[0025] In the following, the environment in which the rolling bearing is exposed to an atmosphere containing hydrogen peroxide or the like is referred to as decontamination, but the above-mentioned environment is not limited to decontamination. For example, it also includes the case in which the rolling bearing is used for industrial purposes using hydrogen peroxide or peracetic acid.

[0026] Hereinafter, the embodiments of the present invention will be described in detail. Note that the present invention is not limited to the embodiments described below, and can be modified and implemented as desired without departing from the gist of the present invention.

[0027] [Rolling bearings] FIG. 1 is a schematic cross-sectional view showing a rolling bearing according to this embodiment. In FIG. 1, a deep groove ball bearing is taken as an example of the rolling bearing 1, and its configuration will be briefly described. The rolling bearing 1 has an annular inner ring 3, an annular outer ring 5 arranged on the outer periphery of the inner ring 3, a plurality of balls (rolling elements) 7 rollably assembled between the inner ring 3 and the outer ring 5 via a cage 9, a shield 11 that seals the inside of the bearing, and grease (not shown) sealed in the space sealed by the shield 11. Note that the rolling bearing 1 shown in FIG. 1 is provided with the shield 11, but in this embodiment, the configuration of the rolling bearing 1 is not limited, and the shield 11 may not be provided. That is, the rolling bearing according to this embodiment is characterized by the grease, and the grease will be described in detail below.

[0028] <Grease> The grease includes a base oil and a thickener. The base oil contains a fluorine oil, and the thickener contains a polytetrafluoroethylene (PTFE) resin powder. The grease containing the fluorine oil and PTFE has excellent high-temperature and low-temperature properties and has extremely excellent oxidation stability. Therefore, a rolling bearing filled with the grease can suppress the occurrence of rust and the like, and can maintain high performance of the rolling bearing.

[0029] Examples of fluorine oils include perfluoropolyether (PFPE) and chlorotrifluoroethylene (CTFE), and among these, it is preferable to use PFPE.

[0030] (Grease mixed consistency: 200 to 295) The worked penetration is a value that indicates the hardness of the grease, and the harder the grease, the smaller the value. Conventionally, in order to reduce the amount of dust generation, that is, to improve the low dust generation characteristics, a hard grease has generally been used. In this embodiment, the worked penetration of the grease is appropriately specified in a range of values ​​higher than conventionally, and it is considered that this can improve the characteristic of preventing the deterioration of the grease not only before decontamination but also after decontamination, that is, the deterioration resistance. As a result, it is considered that the rolling bearing can maintain excellent low dust generation characteristics and ensure a clean environment.

[0031] If the mixed penetration exceeds 295, the grease becomes too soft, so it is assumed that the grease will easily scatter and contaminate the outside. Therefore, the mixed penetration of the grease is 295 or less, preferably 285 or less, and more preferably 275 or less. On the other hand, if the mixed penetration is less than 200, the grease becomes too hard, so the grease cannot absorb excessive stress and is deformed, so it is likely to be affected by decontamination, and the dust generation will worsen due to deterioration. In addition, it becomes difficult to fill the rolling bearing with grease at room temperature. Therefore, the mixed penetration of the grease is 200 or more, preferably 210 or more, and more preferably 220 or more. The mixed penetration of the grease can be measured in accordance with JIS K 2220:2013.

[0032] (Kinematic viscosity of base oil at 40℃: 10mm 2 / s or more 200mm 2 / s or less) By using a base oil with an appropriately adjusted kinetic viscosity and adjusting the mixed penetration of the grease as described above, the torque characteristics of the rolling bearing can be significantly improved. 2 If the kinematic viscosity of the base oil at 40°C is 10 mm / s or more, the desired lubrication can be obtained. 2 / s or more is preferable, and 30 mm 2 / s or more is preferable, and 50 mm 2 It is even more preferable that the ratio is 1 / s or more.

[0033] On the other hand, the kinetic viscosity of the base oil at 40°C is 200mm 2 When the kinematic viscosity of the base oil at 40°C is 200 mm / s or less, the increase in friction resistance can be suppressed, and a more excellent reduction in torque can be achieved. 2 / s or less is preferable, and 150 mm 2 / s or less is more preferable, and 100 mm 2The kinematic viscosity of the base oil can be measured in accordance with JIS K 2283:2000.

[0034] (Thickener content: 30% to 50% by mass) The worked penetration of the grease is affected by the type of base oil used and the content of the thickener. When the content of the thickener is 30% by mass or more relative to the total mass of the grease, the properties of the grease can be ensured and the worked penetration of the grease can be easily adjusted to 295 or less. Therefore, the content of the thickener relative to the total mass of the grease is preferably 30% by mass or more. On the other hand, when the content of the thickener is 50% by mass or less relative to the total mass of the grease, the worked penetration of the grease can be easily adjusted to 200 or more. Therefore, the content of the thickener relative to the total mass of the grease is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.

[0035] (Specific gravity of grease: 1.50 or higher) The specific gravity of the grease is influenced by the content of thickener and the type of base oil, and is also closely related to the mixed penetration of the grease. When the specific gravity of the grease is 1.50 or more, the hardness of the grease is likely to be in the desired range, and the deterioration of the grease is prevented even after decontamination, and excellent low dust generation characteristics and torque characteristics can be maintained. Therefore, the specific gravity of the grease is preferably 1.50 or more, and more preferably 1.80 or more. The specific gravity of the grease can be measured in accordance with JIS K 2249-1:2011.

[0036] (Oxidation stability of grease: 10kPa or less) By appropriately selecting the base oil and thickener contained in the grease, the oxidation stability of the grease can be improved. The oxidation stability of the grease can be expressed by the oxidation stability. If the oxidation stability of the grease is 10 kPa or less, the grease will not change even after decontamination, and excellent low dust generation properties can be maintained, and the performance of the rolling bearing can be maintained at a good level. Therefore, the oxidation stability of the grease is preferably 10 kPa or less, and more preferably 5 kPa or less. The oxidation stability of the grease can be measured in accordance with JIS K 2220:2013.

[0037] (Additives in grease) The grease filled in the rolling bearing according to this embodiment may be composed of a fluorine oil as a base oil and a polytetrafluoroethylene resin powder as a thickener, and may contain various additives to further improve various performances. The content of the additives relative to the total mass of the grease is not particularly limited as long as it is within a range that does not impair the object of the present invention.

[0038] <Rolling bearing operating environment> In conventional rolling bearings, when decontamination is performed with hydrogen peroxide and peracetic acid, the grease is altered and the low dust generation characteristics are reduced. In addition, in order to prevent the deterioration of the low dust generation characteristics, it is necessary to attach a cover that covers the rolling bearing, ball screw, linear guide, etc., and to perform an operation to prevent the grease from being altered. In contrast, in the present embodiment, the attachment of a cover is not necessary, and excellent low dust generation characteristics and torque characteristics can be maintained even after the above-mentioned decontamination is performed. Therefore, the rolling bearing according to the present embodiment is preferably used in an environment exposed to an atmosphere containing at least one of hydrogen peroxide and peracetic acid, and more preferably used in an environment exposed to an atmosphere containing hydrogen peroxide.

[0039] Fields in which the product is used in an environment exposed to atmospheres containing hydrogen peroxide or peracetic acid include the medical and pharmaceutical fields, paper and pulp fields, textile fields, chemical industry fields, electronics industry fields, pollution control fields, mining fields, food fields, metal finishing processing fields, and wood processing fields.

[0040] Specifically, in the medical and pharmaceutical fields, hydrogen peroxide and peracetic acid are used for decontamination of manufacturing equipment for regenerative medicine products, for the production of oxydol, and as intermediate raw materials for pharmaceuticals. In the paper and pulp field, hydrogen peroxide and peracetic acid are used for bleaching various pulps and for deinking and bleaching waste paper. In the textile field, hydrogen peroxide and peracetic acid are used for bleaching natural fibers such as cotton, wool, and silk, and synthetic fibers. In the chemical industry field, hydrogen peroxide and peracetic acid are used as raw materials for organic and inorganic peroxides, organic compounds, and epoxy compounds. In the electronics industry field, hydrogen peroxide and peracetic acid are used for etching and cleaning semiconductors and etching and cleaning printed circuit boards. In the pollution treatment field, hydrogen peroxide and peracetic acid are used for sewage treatment, factory wastewater treatment (deodorization, bacteria, decolorization), and soil improvement. In the mining field, hydrogen peroxide and peracetic acid are used to oxidize metals in the smelting process. In the food industry, hydrogen peroxide and peracetic acid are used for sterilizing food manufacturing equipment and containers. In the metal finishing industry, hydrogen peroxide and peracetic acid are used for surface treatment of metals and purification of plating solutions. In the wood processing industry, hydrogen peroxide and peracetic acid are used for bleaching wood and decorative panels.

[0041] As mentioned above, it is necessary for devices used in the field of regenerative medicine to prevent product mix-up and cross-contamination, and to reduce the number of microorganisms living in the structure and equipment to a pre-specified bacterial count level. For this reason, devices used in the field of regenerative medicine are subjected to a decontamination process in which they are exposed to hydrogen peroxide or the like in order to reduce the number of bacteria to a certain level. Therefore, the rolling bearing according to this embodiment is preferably included in devices used in the medical and pharmaceutical fields, and particularly preferably included in devices used in the field of regenerative medicine.

[0042] In the field of regenerative medicine, one method of decontaminating the inside of a work chamber is, for example, to evaporate and diffuse hydrogen peroxide. Specifically, hydrogen peroxide vaporized by a heater is diffused inside an isolator or in a work chamber, and the oxidizing power of the hydrogen peroxide can kill microorganisms.

[0043] [Actuator] The actuator according to the present embodiment includes the rolling bearing according to the present embodiment, a ball screw supported by the rolling bearing, and a linear guide that guides the direction of movement of a member moved by the ball screw. The actuator thus configured includes the rolling bearing according to the present embodiment with excellent low dust generation characteristics, and therefore can maintain excellent quality.

[0044] It is preferable that a low-temperature chromium fluoride plating film is formed on the surface of the ball screw and the surface of the linear guide. Since the low-temperature chromium fluoride plating film has excellent corrosion resistance, by forming the film on the surface of the ball screw and the linear guide, the actuator according to the present embodiment can be used in a cleaner environment. It is more preferable that the material of the ball screw and the linear guide is stainless steel.

[0045] <Actuator operating environment> As described above, the rolling bearing according to this embodiment is suitable for use in an environment exposed to an atmosphere containing hydrogen peroxide. Therefore, an actuator equipped with the rolling bearing also has excellent resistance to an atmosphere containing hydrogen peroxide. Fields in which the actuator is used in an environment exposed to an atmosphere containing hydrogen peroxide and specific examples of such use are as described above, and it is particularly preferable to use the actuator according to this embodiment in the field of regenerative medicine.

[0046] Conventionally, when an actuator is used in an environment exposed to hydrogen peroxide, covers are generally attached to the rolling bearings, ball screws, and linear guides to prevent particles and the like from scattering from the rolling bearings and ball screws. In contrast, in the actuator according to this embodiment, even when exposed to an environment containing hydrogen peroxide, the grease does not deteriorate and excellent low dust generation characteristics and torque characteristics can be maintained. Therefore, there is no need to attach covers to cover the rolling bearings, ball screws, and linear guides, and the rolling bearings, ball screws, and linear guides can be decontaminated without degrading the performance of the actuator. Therefore, the time and cost required for maintaining the actuator can be reduced, and long-term operation can be achieved at low cost. EXAMPLES

[0047] The present invention will be explained in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples, and can be modified within the scope of the present invention, all of which are included in the technical scope of the present invention. In addition, the various conditions shown below are examples, and the present invention is not limited to the following conditions.

[0048] [Experiment 1] By changing the type of grease, rolling bearings of Example No. 1 and Comparative Example No. 1 were produced, and experiments were carried out to evaluate the cleanliness (low dust generation characteristics) and resistance to deterioration. The experimental procedure is as follows.

[0049] <Grease adjustment> A thickener and a base oil were mixed to prepare a grease for rolling bearings of Example No. 1. A lithium soap and a base oil were mixed to prepare a grease for rolling bearings of Comparative Example No. 1. The blending ratio of the thickener to the base oil in Example No. 1 was 33:67. The materials of the grease are shown below. The base oil used in the grease was measured for its kinematic viscosity at 40°C and 100°C in accordance with JIS K 2283:2000.

[0050] (Grease for rolling bearings of invention example No. 1) Thickener: PTFE (polytetrafluoroethylene) Base oil: (linear) PFPE (perfluoropolyether) (Comparative Example No. 1 Rolling Bearing Grease) Lithium soap Base oil: Mineral oil + poly-α-olefin

[0051] <Measurement of grease properties> (Measurement of worked penetration, specific gravity and oxidation stability) The worked penetration of the obtained grease was measured in accordance with JIS K 2220:2013. The specific gravity of the grease was also measured in accordance with JIS K 2249-1:2011. The oxidation stability of the grease was also measured in accordance with JIS K 2220:2013. The grease materials, base oil kinematic viscosity, and measured values ​​of the grease are shown in Table 1 below.

[0052] <Evaluation of rolling bearings> The obtained grease was filled into the space of a rolling bearing so that the volume of the rolling bearing was almost completely filled, and the rolling bearing was incorporated into an actuator (manufactured by NSK Ltd., model number: XY-HS0005-734) to prepare an actuator for evaluation. The ball screw and linear guide incorporated into the actuator for evaluation were made of SUS440C and had a low-temperature chrome fluoride plating film formed on the surface. Then, using the actuator for evaluation, a cleanliness evaluation test before and after decontamination, and an evaluation test of deterioration resistance were performed. The test method and evaluation criteria for each evaluation test are described in detail below. The evaluation results of each test are also shown in Table 1 below.

[0053] (Test method for evaluating cleanliness (before decontamination)) In an environment of 23℃ 50%RH, the operating speed is 50mm / s (1500min -1 ), acceleration / deceleration is 200mm / s 2The actuator was operated for at least 180 minutes under the condition of vertical placement. The amount of dust generated from the actuator was measured using a particle counter (Beckman Coulter, Inc., Portable Airborne Particle Counter MET ONE Model 3411) from the start to the end of operation.

[0054] (Criteria for evaluation of cleanliness (before decontamination)) The low dust generation characteristics before decontamination were evaluated based on the Federal Standard 209E (FED STD) to see if it met Class 100. 3 ) with 100 particles of 0.5 μm or more (pieces / ft 3 ) or less was considered to be a pass (○). On the other hand, measurements were continued from the start to the end of operation, and 3 ) with 100 particles of 0.5 μm or more (pieces / ft 3 ) was deemed a failure (×).

[0055] The evaluation criteria for particle quantity (number of particles) were based on FED STD 209E.

[0056] (Test method for evaluating resistance to deterioration) The molecular structure of the grease in the actuator for evaluation was analyzed in advance by Fourier transform infrared spectroscopy (FT-IR). After that, the actuator for evaluation was placed in a safety cabinet, and a hose connected to a hydrogen peroxide gas decontamination system was passed through the safety cabinet to form a circulatory flow. The decontamination was performed by running the decontamination operation so as to use up all 30 ml of 60% hydrogen peroxide concentrated solution. In addition, a sealing procedure was taken to prevent hydrogen peroxide gas from leaking from the safety cabinet. After that, the molecular structure of the grease in the actuator for evaluation after decontamination was analyzed by FT-IR. The equipment used is shown below.

[0057] Safety cabinet: Japan Airtech Co., Ltd., model number BHC-1310IIA2, space volume approx. 0.5 m 3 Hydrogen peroxide gas decontamination system: Optima Corporation, model number PASSTECH S1 FT-IR: BRUKER, infrared spectrophotometer, model ALPHAII

[0058] (Criteria for evaluating resistance to deterioration) The FT-IR results of the grease in the actuator for evaluation before and after decontamination were compared, and a case in which there was little change in the peak before and after decontamination was judged to be pass (◯).On the other hand, a case in which a noticeable peak appeared after decontamination was judged to be fail (×).

[0059] (Test method for evaluating cleanliness (after decontamination)) Using the actuator for evaluation that had been decontaminated by the above-mentioned deterioration resistance test, the actuator for evaluation was operated and the amount of dust generated was measured in the same manner as in the method for evaluating the cleanliness before decontamination.

[0060] (Criteria for evaluation of cleanliness (after decontamination)) The cleanliness evaluation criteria after decontamination were the same as those before decontamination.

[0061] [Table 1]

[0062] As shown in Table 1 above, the rolling bearing of Example No. 1 had excellent resistance to deterioration because the grease material and worked penetration were within the ranges specified in the present invention, and the low dust generation characteristics were excellent before decontamination and maintained even after decontamination. On the other hand, the rolling bearing of Comparative Example No. 1 had a poor evaluation result for resistance to deterioration because the grease material and worked penetration were outside the ranges specified in the present invention, the grease was deteriorated after decontamination, and the low dust generation characteristics after decontamination were reduced. From these results, it was shown that the rolling bearing of Example No. 1 is particularly suitable for devices used in clean environments. Specifically, it was shown that even when severe decontamination is performed, such as in the field of regenerative medicine, it is possible to prevent an increase in the amount of dust generation and maintain the excellent performance of the rolling bearing.

[0063] [Experiment 2] Two types of grease within the range specified by the present invention were prepared, and rolling bearings were filled with the grease to produce rolling bearings of invention example No. 1 and invention example No. 2, and an experiment was conducted to evaluate the torque characteristics. The experimental procedure is as follows.

[0064] <Grease adjustment> Grease for rolling bearings of invention example No. 1 was prepared in the same manner as in the above experiment 1. Grease for rolling bearings of invention example No. 2 was also prepared by changing the ratio of the fluorinated oil and thickener used in the base oil. Furthermore, in the same manner as in experiment 1, the kinetic viscosity of the base oil used in the grease was measured, and the mixed penetration, specific gravity, and oxidation stability of the grease were also measured.

[0065] <Evaluation of rolling bearings> The obtained grease was filled into a rolling bearing in the same manner as in the above-mentioned Experiment 1, and an evaluation actuator including this rolling bearing was fabricated. Then, the evaluation actuator was used to carry out an evaluation of the torque characteristics. The evaluation test method and evaluation criteria for the torque characteristics are described in detail below.

[0066] (Test method for evaluating torque characteristics) The actuator was fabricated for evaluation and the operating speed was set to 50 mm / s (1500 min -1 ), acceleration / deceleration is 200mm / s 2 The motor was operated in a vertical position, and the operating torque of the motor was measured to confirm that it was functioning properly. The actual motor operating torque was measured using software (support software MEXE02, manufactured by Oriental Motor Co., Ltd.).

[0067] (Evaluation criteria for torque characteristics) If the actuator for evaluation operated without any problems, it was judged as passed (○), and if the motor power of the actuator for evaluation was insufficient and it stopped operating, it was judged as failed (×). The evaluation results of the base oil kinematic viscosity, the mixed penetration, specific gravity and oxidation stability of the grease, and the torque characteristics of the invention examples No. 1 and No. 2 are shown in Table 2 below.

[0068] [Table 2]

[0069] As shown in Table 2 above, the greases used in the rolling bearings of invention samples 1 and 2 were both prepared from materials specified in the present invention, and their worked penetrations were also within the range specified in the present invention. Furthermore, in the rolling bearing of invention sample 1, the base oil kinematic viscosity was within the preferred range specified in the present invention, so the torque characteristics were excellent. [Explanation of symbols]

[0070] 1. Rolling bearings 3. Inner Circle 5 Outer ring 7 Balls (rolling elements) 9 Cage 11 Shield

Claims

1. A rolling bearing filled with grease containing a base oil and a thickener, wherein the base oil contains a fluorine oil, the thickener contains polytetrafluoroethylene resin powder, the consistency of the grease is 200 or more and 295 or less, the kinematic viscosity of the base oil at 40°C is 50 mm2 / s or more and 100 mm2 / s or less, the fluorine oil is perfluoropolyether, the content of the thickener with respect to the total mass of the grease is 30% by mass or more and 50% by mass or less, and is used in an environment exposed to an atmosphere containing at least one of hydrogen peroxide and peracetic acid. A rolling bearing characterized by this.

2. The rolling bearing according to Claim 1, characterized in that the specific gravity of the grease is 1.50 or more.

3. The rolling bearing according to Claim 1, characterized in that the oxidation stability of the grease is 10 kPa or less.

4. The rolling bearing according to any one of Claims 1 to 3, characterized in that it is included in a device used in the field of regenerative medicine.

5. An actuator comprising the rolling bearing according to any one of Claims 1 to 3, a ball screw supported by the rolling bearing, and a linear guide for guiding the moving direction of a member moved by the ball screw.

6. The actuator according to Claim 5, characterized in that a low-temperature chromium fluoride plating film is formed on the surface of the ball screw and the surface of the linear guide.

7. The actuator according to Claim 5, which is used in an environment exposed to an atmosphere containing at least one of hydrogen peroxide and peracetic acid and does not have a cover covering the rolling bearing, the ball screw, and the linear guide.

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