USRE48337E1 - Rolling bearing and its packaging method - Google Patents

Rolling bearing and its packaging method Download PDF

Info

Publication number
USRE48337E1
USRE48337E1 US16/442,851 US201316442851A USRE48337E US RE48337 E1 USRE48337 E1 US RE48337E1 US 201316442851 A US201316442851 A US 201316442851A US RE48337 E USRE48337 E US RE48337E
Authority
US
United States
Prior art keywords
bearing
corrosion inhibitor
volatile corrosion
chloride ions
rolling
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
US16/442,851
Inventor
Kyohei MATSUNAGA
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NSK Ltd
Original Assignee
NSK Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=51988237&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=USRE48337(E1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by NSK Ltd filed Critical NSK Ltd
Priority to US16/442,851 priority Critical patent/USRE48337E1/en
Application granted granted Critical
Publication of USRE48337E1 publication Critical patent/USRE48337E1/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C41/00—Other accessories, e.g. devices integrated in the bearing not relating to the bearing function as such
    • F16C41/04—Preventing damage to bearings during storage or transport thereof or when otherwise out of use
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30—Parts of ball or roller bearings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D81/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D81/02—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents specially adapted to protect contents from mechanical damage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D81/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D81/18—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents providing specific environment for contents, e.g. temperature above or below ambient
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D81/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
    • B65D81/24—Adaptations for preventing deterioration or decay of contents; Applications to the container or packaging material of food preservatives, fungicides, pesticides or animal repellants
    • B65D81/26—Adaptations for preventing deterioration or decay of contents; Applications to the container or packaging material of food preservatives, fungicides, pesticides or animal repellants with provision for draining away, or absorbing, or removing by ventilation, fluids, e.g. exuded by contents; Applications of corrosion inhibitors or desiccators
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D85/00—Containers, packaging elements or packages, specially adapted for particular articles or materials
    • B65D85/58—Containers, packaging elements or packages, specially adapted for particular articles or materials for ball bearings, washers, buttons or like spherical or disc-shaped articles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
    • F16C19/52—Bearings with rolling contact, for exclusively rotary movement with devices affected by abnormal or undesired conditions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30—Parts of ball or roller bearings
    • F16C33/66—Special parts or details in view of lubrication
    • F16C33/6603—Special parts or details in view of lubrication with grease as lubricant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30—Parts of ball or roller bearings
    • F16C33/66—Special parts or details in view of lubrication
    • F16C33/6603—Special parts or details in view of lubrication with grease as lubricant
    • F16C33/6607—Retaining the grease in or near the bearing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D2585/00—Containers, packaging elements or packages specially adapted for particular articles or materials
    • B65D2585/68—Containers, packaging elements or packages specially adapted for particular articles or materials for machines, engines, or vehicles in assembled or dismantled form
    • B65D2585/6802—Containers, packaging elements or packages specially adapted for particular articles or materials for machines, engines, or vehicles in assembled or dismantled form specific machines, engines or vehicles
    • B65D2585/6897—Containers, packaging elements or packages specially adapted for particular articles or materials for machines, engines, or vehicles in assembled or dismantled form specific machines, engines or vehicles others
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
    • F16C19/02—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows
    • F16C19/14—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load
    • F16C19/16—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load with a single row of balls
    • F16C19/163—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load with a single row of balls with angular contact
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
    • F16C19/22—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings
    • F16C19/24—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings for radial load mainly
    • F16C19/26—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings for radial load mainly with a single row of rollers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
    • F16C19/22—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings
    • F16C19/24—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings for radial load mainly
    • F16C19/28—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings for radial load mainly with two or more rows of rollers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2223/00—Surface treatments; Hardening; Coating
    • F16C2223/30—Coating surfaces
    • F16C2223/32—Coating surfaces by attaching pre-existing layers, e.g. resin sheets or foils by adhesion to a substrate; Laminating
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2240/00—Specified values or numerical ranges of parameters; Relations between them
    • F16C2240/40—Linear dimensions, e.g. length, radius, thickness, gap
    • F16C2240/60—Thickness, e.g. thickness of coatings
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49636—Process for making bearing or component thereof
    • Y10T29/49703—Sealing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49636—Process for making bearing or component thereof
    • Y10T29/49707—Bearing surface treatment

Definitions

  • the present invention relates a rolling bearing and its packaging method.
  • Bearings are generally packaged during storage or transport, and are unpacked and charged with grease immediately before use. To prevent rusting during storage or transport, the bearings are packaged in a state in which antirust oil is applied to the entire surface of the bearing. Accordingly, if the bearing is charged with grease directly after the unpacking, the grease does not firmly adhere to a surface to be lubricated due to the antirust oil, and the grease may leak out at an early stage during an initial running-in period or in a subsequent operation, resulting in a grease life being reduced.
  • the maximum dmn value of a bearing during its operation is high, at least 500,000, and low temperature rise characteristics are required. Accordingly, to prevent stirring resistance due to excessive lubricant, a grease charge amount is reduced as compared with bearings used in general applications, such as motor bearings.
  • a charging amount of grease in a bearing for a machine tool is 10 vol % to 20 vol %, sometimes 10 vol % to 15 vol % of a bearing interior space. Therefore, if a bearing for a machine tool is charged with grease directly after the unpacking as described above, the grease leaks out and the amount of residual grease becomes extremely small.
  • Patent Document 1 applying antirust oil on a surface of a bearing at a film thickness of 40 ⁇ m or less, packaging the entire bearing with a volatile corrosion inhibitor film, and keeping a pressure-reduced condition between the volatile corrosion inhibitor film and the bearing. Because an adhered amount of the antirust oil is 40 ⁇ m or less, effects on grease can be suppressed even if the grease is provided without undergoing cleaning and degreasing after the unpacking. Also, due to an airtight packaging by the volatile corrosion inhibitor film, a sufficient antirust effect can be obtained even if the adhered amount of antirust oil is reduced to 40 ⁇ m or less.
  • Patent Document 1 JP 2006-322604 A
  • a rolling bearing including an inner ring, an outer ring, and a plurality of rolling elements retained between the inner ring and the outer ring by a retainer in a rollable manner, wherein antirust oil is provided to adhere, at an average film thickness of 4.5 ⁇ m to 10 ⁇ m, to an entire surface of the bearing from which chloride ions and sulfate ions are removed, the entire bearing is covered with a volatile corrosion inhibitor film, and a space between the volatile corrosion inhibitor film and the bearing is kept in a pressure-reduced condition.
  • the antirust oil is provided to adhere after removing chloride ions and sulfate ions and then sealed and packaged by a volatile corrosion inhibitor film, a favorable antirust performance can be obtained while reducing an adhered amount of antirust oil than before. Therefore, even if grease is provided without cleaning or degreasing after unpacking, effect by the antirust oil is further reduced, so that lubrication performance and lifetime are improved.
  • FIG. 1 is a graph showing a relationship between storage conditions of bearings and amounts of residual chloride ions on surfaces of the bearings.
  • FIG. 3 is a perspective view showing a single-row cylindrical roller bearing as another example of a rolling bearing according to the invention.
  • FIG. 5 is a perspective view showing a double-row cylindrical roller bearing as yet another example of a rolling bearing according to the invention.
  • FIG. 6 is a perspective view showing a double-row cylindrical roller bearing as yet another example of a rolling bearing according to the invention, illustrating a state in which an inner ring assembly, including an inner ring, rolling elements and a retainer assembled together, and an outer ring are separately packaged.
  • FIG. 9 is a graph showing results of Test example 2.
  • FIG. 10 is a graph showing results of Test example 3.
  • Chloride ions and sulfate ions are adhered to the bearing surface from various machines or chemicals and workers during manufacturing processes of the bearing.
  • it may be cleaned with a water substitution type cleaning liquid.
  • an amount of the residual chloride ions on the surface of the rolling bearing be 0.2 ng/mm 2 to 10 ng/mm 2 .
  • an amount of chloride ions in the tap water is regulated to be kept to 0.1 mg/L or more, and also defined is a water quality management target value by which the upper threshold is limited to 1 mg/L or less in view of taste or smell. Therefore, in the manufacturing of the rolling bearing, the grinding water will also contain chloride ions of 0.1 mg/L to 1 mg/L. During grinding, a large amount of grinding water of approximately several tens liters is applied to the rolling bearing, and thus a significant amount of chloride ions are adhered on the rolling bearing.
  • chloride ions are contained in human body fluids (such as sweat or saliva), and thus chloride ions are remained in locations where hands are touched. Further, chloride ions are also contained in the atmosphere, and thus, chloride ions in the atmosphere are adhered on the rolling bearing exposed to the atmosphere. Even if the rolling bearing is contained in a sealed container to prevent exposing to the atmosphere, adhesion of a trace amount of chloride ions thereon is inevitable.
  • FIG. 1 a relationship between storage conditions (outdoor storage in the atmosphere, indoor storage in the atmosphere, and indoor storage in an air-tight container) of bearings and amounts of residual chloride ions on surfaces of the bearings is shown.
  • the measurement of amounts of residual chloride ions was performed according to the following procedures (rubber gloves are used in each step) and also was performed using a chlorine ion detector tube 201SA produced by Komyo Rikagaku Kogyo K.K.
  • the amount of chloride ions per unit area is limited to 0.2 ng/mm 2 to 10 ng/mm 2 .
  • the antirust oil is not particularly limited if the antirust oil is one in which stickiness is hardly occurred so that workability is excellent and also an adhered amount thereof can be easily controlled, but, for example, antirust oil, which does not contain petrolatum, is preferably employed.
  • viscosity of the antirust oil is preferably in a range of 10 cst to 60 cst.
  • a method of adhering the antirust oil is not particularly limited if a film thickness thereof can be adjusted, but, for example, can include a centrifugal deoiling method, an air blowing method, or a vacuum heating method.
  • the air blowing method is preferably employed.
  • An adhered amount of antirust oil is set to an average film thickness of 4.5 ⁇ m to 10 ⁇ m. If the average film thickness is less than 4.5 ⁇ m, it is difficult to keep antirust performance for a long time. In addition, because the antirust oil is reacted with grease to cause precipitation of crystals and thus to reduce an acoustic property, the reaction thereof with grease is likely to be occurred if the adhered amount of antirust oil exceeds an average film thickness of 10 ⁇ m.
  • the volatile corrosion inhibitor film may be a resin film, such as polyethylene film, containing an antirust agent, such as organic carboxylic acid amine salts, phosphoric acid amine salts, amine carbonate salts, heterocyclic amine salts, or the like.
  • an antirust agent such as organic carboxylic acid amine salts, phosphoric acid amine salts, amine carbonate salts, heterocyclic amine salts, or the like.
  • the antirust agents can include dicyclohexyl ammonium nitrite, dicyclohexyl ammonium caprylate, cyclohexylamine carbamate, cyclohexylamine laurate, diisopropyl ammonium nitrite, nitronaphthalene ammonium nitrite, ammonium benzoate, cyclohexylamine benzoate salts, dicyclohexylamine phosphate salts, and the like.
  • the volatile corrosion inhibitor film in a form of a bag is preferably used.
  • the volatile corrosion inhibitor film is preferably transparent, and by making the volatile corrosion inhibitor film transparent, stamping or the like can be checked in a packaged state.
  • inspection results such as dimensional differences
  • the inspection results can be checked without polluting the bearing.
  • the inspection results can be more easily checked.
  • the volatile corrosion inhibitor film and the bearing becomes a sealed state by reducing a pressure therebetween. Also, to keep such a pressure-reduced condition obtained by vacuum drawing, sealing, such as heat sealing, is performed.
  • the packaging described above may be performed in a state in which grease is provided in a bearing interior space defined by an inner ring, an outer ring and rolling elements, or in a state in which the grease is not provided.
  • grease charge before use becomes unnecessary. Because the space between the volatile corrosion inhibitor film and the bearing is in a pressure-reduced condition, the packaging film enters a space between inner and outer rings in a concave manner to prevent grease from being flowed out even if it is vibrated during transport.
  • the present invention is not limited to types of rolling bearings, and for example, can be applied to packaging of an angular ball bearing 1 as shown in FIG. 2 .
  • the angular ball bearing 1 immediately after manufacturing is cleaned with a water substitution type cleaning liquid to remove chloride ions and sulfate ions and then after antirust oil is provided to adhered thereto at an average film thickness of 4.5 ⁇ m to 10 ⁇ m, is put in a bag made of a volatile corrosion inhibitor film 10 , and the bag is vacuum drawn and sealed by heat sealing or the like.
  • the reference numeral 11 denotes a sealing portion.
  • the present invention can be applied in a similar manner in packaging a single-row cylindrical roller bearing 2 .
  • an inner ring-side member of the single-row cylindrical roller bearing 2 which includes an inner ring 2 A, cylindrical rollers 2 B and a retainer 2 C assembled together with each other, and an outer ring 2 D thereof may be put in separate bags made of a volatile corrosion inhibitor film 10 .
  • a sealed state thereof can be kept until immediately before the bearing is mounted, thereby more effectively inhibiting adhering of foreign substances in the atmosphere or rusting.
  • a double-row cylindrical roller bearing 3 may be packaged as shown in FIG. 5 and also an inner ring-side member of the double-row cylindrical roller bearing 3 , which includes an inner ring 3 A, cylindrical rollers 3 B and a retainer 3 C assembled together with each other, and an outer ring 3 D thereof may be put and sealed in separate bags made of a volatile corrosion inhibitor film 10 as shown in FIG. 6 .
  • Angular ball bearings (inner diameter: 40 mm, outer diameter: 68 mm, and width: 15 mm) of a bearing number 7008CTYNDBLP4 immediately after assembly were prepared and was cleaned with a water substitution type cleaning liquid (“Aqua Solvent” produced by Aqua Chemical Co., Ltd.) to remove chloride ions and sulfate ions on a surface thereof.
  • a water substitution type cleaning liquid (“Aqua Solvent” produced by Aqua Chemical Co., Ltd.) to remove chloride ions and sulfate ions on a surface thereof.
  • lubricating oil (“ANTIRUST P-2810” produced by JX Nippon Oil & Energy Corporation; viscosity: 12 cst), which does not include petrolatum, was adhered as an antirust agent on the entire surface of the bearings by an air blowing method while varying an adhering amount thereof.
  • each test sample was left in a high temperature and high humidity environment of 50° C.-90% RH and periods of time until rust was occurred were compared.
  • an effect of accelerating rusting by approximately 30 times is obtained as compared when samples were left at 20° C.-70% RH, which are the average temperature and humidity in Japan, and the equivalent numbers of years are shown in the figure.
  • the results are shown in FIG. 7 , but it can be found that, when the adhered amount of antirust oil is less than an average film thickness of 4.5 ⁇ m, antirust performance in a packed state is significantly decreased. From the results, it can be found that a favorable antirust performance can be kept for a long time by setting the adhered amount of antirust oil to an average film thickness of 4.5 ⁇ m or more.
  • Test example 1 The test samples fabricated in Test example 1 were opened and then a bearing interior space defined by an inner ring, an outer ring and balls was charged with grease (MTE produced by NSK Ltd.) of 1.1 g (15% of the bearing interior space volume), thereby fabricating test bearings. Then, after rotating the bearings for 24 hours at conditions as described below, using a tester as shown in FIG. 8 , grease residual rates were measured. Also, for comparison, the same bearings, on which cleaning and degreasing was performed and antirust oil was not adhered, were charged with grease to fabricate comparative test bearings, and grease residual rates were in the same manner.
  • grease produced by NSK Ltd.
  • grease residual rate means a value which is obtained by subtracting a percentage, which is represented by a value obtained by dividing a difference between a bearing weight (M1) in a grease-charged condition before rotating and a bearing weight (M2) after rotating by a charged amount of grease (M3), from 100, and if the grease residual rate is low, a grease life is shortened.
  • Driving method Belt driving
  • the results are shown in FIG. 9 , but it can be found that when the average film thickness is up to 10 ⁇ m, the test bearings have a grease residual rate of 97% on average as compared with the comparative test bearings having a grease residual rate of 99%, and therefore, the test bearings have a grease holding ability equivalent to those in a conventional using method in which grease charge is performed after cleaning and degreasing bearings. On the other hand, when the average film thickness is 15 ⁇ m or more, the grease residual rate tends to be decreased. From the results, it can be found that a grease holding ability equivalent to those in a conventional case, and thus a lubrication lifetime can be kept by setting the adhered amount of antirust oil to an average film thickness of 10 ⁇ m or less.
  • grease MTE or MTS produced by NSK Ltd., or ISOFLEX NBU 15 produced by NOK KLÜBER Co., Ltd.
  • Test samples in which the adhered amount of antirust oil in Test example 1 were adjusted to an average film thickness of 10 ⁇ m, were opened and then were charged with grease (MTE produced by NSK Ltd.) of 1.1 g (15% of the bearing interior space volume), thereby fabricating test bearings. Also, for comparison, comparative test bearings, which were charged with grease without adhering antirust oil after cleaning and degreasing, were fabricated. Then, each test bearing was rotated at conditions as described below, using the test apparatus used in Test example 2, and a temperature of the outer ring thereof at that time was measured.
  • grease produced by NSK Ltd.
  • chloride ions were newly adhered by treatments shown in Table 1, and then an amount of chloride ions was measured.
  • an amount of chloride ions was measured.
  • a liquid was collected from the bath and then an amount of chloride ions therein were measured by a ion chromatography analyzer, DX-120, and a separation column, IonPacAS12A (4 mm), which are produced by Dionex K.K.
  • the measurement method was performed at conditions identical to those of Explanation FIG. 6 of JIS K0127. Qualification was performed for chloride ions, thereby calculating an amount per unit area. The results are shown in Table 1.
  • rusting can be prevented when an amount of chloride ions is 5 ng/mm 2 to 10 ng/mm 2 .
  • an amount of chloride ions contained in a grinding water is 0.1 mg/L, which is a minimum defined in the Waterworks Law, it is believed that rolling bearings, which are typically ground and from which chloride ions does not removed, have chloride ions of few tens to few hundreds ng/mm 2 adhered thereon, but when chloride ions are not removed, rusting cannot be prevented if the antirust oil has a thin film thickness of less than 4.5 ⁇ m.
  • the present invention is suitable for storing and transporting machine tool bearings (in particular, machine tool spindle bearings).

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Food Science & Technology (AREA)
  • Rolling Contact Bearings (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)

Abstract

To provide a rolling bearing in which a favorable antirust performance can be obtained while reducing an amount of antirust oil than before, after removing chloride ions and sulfate ions from the entire surface of the bearing, antirust oil is provided to adhere thereto at an average film thickness of 4.5 μm to 10 μm, and the entire bearing is covered with a volatile corrosion inhibitor film such that a space between the volatile corrosion inhibitor film and the bearing is kept in a pressure-reduced condition.

Description

This application is a reissue application of U.S. Pat. No. 9,377,057, which was filed as U.S. application Ser. No. 14/655,403 on Jun. 25, 2015, issued on Jun. 28, 2016, which is a U.S. national stage application under 35 U.S.C. 371 of International Application No. PCT/JP2013/076967 filed on Oct. 3, 2013 in the Japan Patent Office, and which claims priority to JP 2013-115810 filed May 31, 2013, the disclosures of each of which are hereby incorporated by reference in their entirety.
TECHNICAL FIELD
The present invention relates a rolling bearing and its packaging method.
BACKGROUND ART
In recent years, for machine tool bearings (in particular, machine tool spindle bearings), minimal quantity lubrication methods such as oil lubrication, e.g., oil-air or oil-mist lubrication, and grease lubrication are used to reduce a temperature rise due to stirring resistance of lubricating oil. In oil lubrication, measures should be taken in view of a cost increase due to use of air, environmental considerations with regard to wind noise due to rolling elements cutting the air injected from a nozzle into a bearing interior and passing through the bearing interior, and outflow of used oil through an oil discharging hole, and also working environment considerations with regard to impact on human bodies, deterioration of visibility and the like due to floating of oil mists.
In light of such backgrounds, such as energy saving and reduction of environmental impact, for machine tool spindle bearings, there are increasing needs for a grease lubrication method in which there is no usage of air or outflow of lubricating oil.
Bearings are generally packaged during storage or transport, and are unpacked and charged with grease immediately before use. To prevent rusting during storage or transport, the bearings are packaged in a state in which antirust oil is applied to the entire surface of the bearing. Accordingly, if the bearing is charged with grease directly after the unpacking, the grease does not firmly adhere to a surface to be lubricated due to the antirust oil, and the grease may leak out at an early stage during an initial running-in period or in a subsequent operation, resulting in a grease life being reduced.
In particular in the case of machine tools, the maximum dmn value of a bearing during its operation is high, at least 500,000, and low temperature rise characteristics are required. Accordingly, to prevent stirring resistance due to excessive lubricant, a grease charge amount is reduced as compared with bearings used in general applications, such as motor bearings. A charging amount of grease in a bearing for a machine tool is 10 vol % to 20 vol %, sometimes 10 vol % to 15 vol % of a bearing interior space. Therefore, if a bearing for a machine tool is charged with grease directly after the unpacking as described above, the grease leaks out and the amount of residual grease becomes extremely small.
In addition, in grease lubrication, lubricating oil inside the bearing is not exchanged during use. Accordingly, if foreign substances enter the bearing interior during packaging, the foreign substances remain and hinder a rotation.
Therefore, after the unpacking and before charging with grease, it is necessary to clean and degrease bearings to remove the adhered antirust oil and foreign substances inside the bearings, causing a burden when mounting the bearings. Thus, the applicant proposes, in Patent Document 1, applying antirust oil on a surface of a bearing at a film thickness of 40 μm or less, packaging the entire bearing with a volatile corrosion inhibitor film, and keeping a pressure-reduced condition between the volatile corrosion inhibitor film and the bearing. Because an adhered amount of the antirust oil is 40 μm or less, effects on grease can be suppressed even if the grease is provided without undergoing cleaning and degreasing after the unpacking. Also, due to an airtight packaging by the volatile corrosion inhibitor film, a sufficient antirust effect can be obtained even if the adhered amount of antirust oil is reduced to 40 μm or less.
PRIOR ART DOCUMENT Patent Document
Patent Document 1: JP 2006-322604 A
SUMMARY OF INVENTION Problem to be Solved by Invention
However, there are strong demands for further reducing effects on grease by reducing the adhered amount of antirust oil, and accordingly, it is an object of the present invention to provide a rolling bearing in which a favorable antirust performance can be obtained while further reducing the amount of antirust oil than before.
Means for Solving the Problem
To solve the above object, the present invention provides a rolling bearing and its packaging method described below. (1) A rolling bearing including an inner ring, an outer ring, and a plurality of rolling elements retained between the inner ring and the outer ring by a retainer in a rollable manner, wherein antirust oil is provided to adhere, at an average film thickness of 4.5 μm to 10 μm, to an entire surface of the bearing from which chloride ions and sulfate ions are removed, the entire bearing is covered with a volatile corrosion inhibitor film, and a space between the volatile corrosion inhibitor film and the bearing is kept in a pressure-reduced condition.
(2) The rolling bearing according to (1), wherein an amount of residual chloride ions adhered to the rolling bearing per unit area is 0.2 ng/mm 210 ng/mm2.
(3) The rolling bearing according to (1) or (2), wherein the entire bearing is covered with the volatile corrosion inhibitor film and the space between the volatile corrosion inhibitor film and the bearing is kept in the pressure-reduced condition, in a state in which a bearing interior space defined by the inner ring, the outer ring and the rolling elements is charged with grease.
(4) A method of packaging a rolling bearing after assembling the rolling bearing from bearing components, the method including after removing chloride ions and sulfate ions from the entire surface of the bearing, providing antirust oil to adhere thereto at an average film thickness of 4.5 μm to 10 μm, and covering the entire bearing with a volatile corrosion inhibitor film such that a space between the volatile corrosion inhibitor film and the bearing is kept in a pressure-reduced condition.
(5) The method of packaging the rolling bearing according to (4), wherein the chloride ions and the sulfate ions are removed from the entire surface of the rolling bearing such that an amount of residual chloride ions adhered to the rolling bearing per unit area is 0.2 ng/mm2 to 10 ng/mm2.
(6) The method of packaging the rolling bearing according to (4) or (5), wherein after the adhesion of the antirust oil, a bearing interior space defined by an inner ring, an outer ring and rolling elements is charged with grease, and the entire bearing is covered with the volatile corrosion inhibitor film such that the space between the volatile corrosion inhibitor film and the bearing is kept in the pressure-reduced condition.
Advantageous Effects of Invention
According to the present invention, because the antirust oil is provided to adhere after removing chloride ions and sulfate ions and then sealed and packaged by a volatile corrosion inhibitor film, a favorable antirust performance can be obtained while reducing an adhered amount of antirust oil than before. Therefore, even if grease is provided without cleaning or degreasing after unpacking, effect by the antirust oil is further reduced, so that lubrication performance and lifetime are improved.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a graph showing a relationship between storage conditions of bearings and amounts of residual chloride ions on surfaces of the bearings.
FIG. 2 is a perspective view showing an angular ball bearing as an example of a rolling bearing according to the present invention.
FIG. 3 is a perspective view showing a single-row cylindrical roller bearing as another example of a rolling bearing according to the invention.
FIG. 4 is a perspective view showing a single-row cylindrical roller bearing as yet another example of a roller bearing according to the invention, illustrating a state in which an inner ring assembly, including an inner ring, rolling elements and a retainer assembled together, and an outer ring are separately packaged.
FIG. 5 is a perspective view showing a double-row cylindrical roller bearing as yet another example of a rolling bearing according to the invention.
FIG. 6 is a perspective view showing a double-row cylindrical roller bearing as yet another example of a rolling bearing according to the invention, illustrating a state in which an inner ring assembly, including an inner ring, rolling elements and a retainer assembled together, and an outer ring are separately packaged.
FIG. 7 is a graph showing results of Test Example 1.
FIG. 8 is a diagram illustrating a test apparatus used in Test Example 2 and Test Example 4.
FIG. 9 is a graph showing results of Test example 2.
FIG. 10 is a graph showing results of Test example 3.
FIG. 11 is a graph showing results of Test example 4.
 EMBODIMENTS OF INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings.
According to a rolling bearing of the present invention, after assembling, and after removing chloride ions and sulfate ions from the entire surface of the bearing, antirust oil provided to adhered thereto and is sealed by a volatile corrosion inhibitor film. By removing the rust-inducing chloride ions and the sulfate ions, a favorable antirust performance can be ensured even with an adhered amount of antirust oil being reduced to an average film thickness of 4.5 μm to 10 μm, so that effect of the antirust oil on grease can be eliminated even if the grease is provided without cleaning or degreasing after unpacking.
Chloride ions and sulfate ions are adhered to the bearing surface from various machines or chemicals and workers during manufacturing processes of the bearing. To remove chloride ions and sulfate ions, for example, it may be cleaned with a water substitution type cleaning liquid. By this cleaning, it is preferable that an amount of the residual chloride ions on the surface of the rolling bearing be 0.2 ng/mm2 to 10 ng/mm2.
Grinding is mostly used in the manufacturing processes of the rolling bearing, but grinding is generally performed while applying a large amount of grinding water to prevent dimensional changes of products due to heat accompanied with such processing. A tap water is used as the grinding water, and the tap water inevitably contains chlorine components, namely chloride ions.
Under the Waterworks Law, an amount of chloride ions in the tap water is regulated to be kept to 0.1 mg/L or more, and also defined is a water quality management target value by which the upper threshold is limited to 1 mg/L or less in view of taste or smell. Therefore, in the manufacturing of the rolling bearing, the grinding water will also contain chloride ions of 0.1 mg/L to 1 mg/L. During grinding, a large amount of grinding water of approximately several tens liters is applied to the rolling bearing, and thus a significant amount of chloride ions are adhered on the rolling bearing.
In addition, a large amount of chloride ions is contained in human body fluids (such as sweat or saliva), and thus chloride ions are remained in locations where hands are touched. Further, chloride ions are also contained in the atmosphere, and thus, chloride ions in the atmosphere are adhered on the rolling bearing exposed to the atmosphere. Even if the rolling bearing is contained in a sealed container to prevent exposing to the atmosphere, adhesion of a trace amount of chloride ions thereon is inevitable.
In FIG. 1, a relationship between storage conditions (outdoor storage in the atmosphere, indoor storage in the atmosphere, and indoor storage in an air-tight container) of bearings and amounts of residual chloride ions on surfaces of the bearings is shown. The measurement of amounts of residual chloride ions was performed according to the following procedures (rubber gloves are used in each step) and also was performed using a chlorine ion detector tube 201SA produced by Komyo Rikagaku Kogyo K.K.
(Measurement Method)
(1) Masking portions other than a measurement portion (such as a bearing outer peripheral surface) on a bearing by a masking tape after being stored in the atmosphere or in a sealed container for a predetermined period of tune.
(2) Providing deionized water of 100 mL in a poly beaker.
(3) Folding a gauze suitably and soaking it in the deionized water in the beaker.
(4) Wiping the measurement portion with the wetted gauze in parallel directions.
(5) Thoroughly rinsing the gauze is thoroughly with the deionized water in the beaker.
(6) Repeating (4) and (5).
(7) After collecting, thoroughly cleaning a surface of the used rubber gloves with a deionized water of 50 mL, and returning the deionized water used for the cleaning back in the beaker to use as a sample liquid.
(8) Cutting both ends of a chlorine ion detector tube by a tip cutter and placing the chlorine ion detector tube in the sample liquid with an arrow oriented upward.
(9) If salt exists in the sample liquid, a white discoloration layer appears from the lower end of the detector tube. When the sample liquid is permeated to the upper end of the detector tube, the detector tube is taken out and then chloride content in the sample liquid is read by a scale at a distal end of the discoloration layer.
As shown in FIG. 1, it can be found that, even if rolling bearings are stored in the atmosphere or in the sealed container, chlorides have been adhered thereon. The amount of residual chloride ions adhered to the bearing per unit area is calculated by the following equation, where V is an amount of residual chloride ions adhered to the bearing per unit area, T is an adhered amount of chloride ions, and S is a surface area of a measurement portion of the bearing used upon measuring of an amount of chloride ions.
V=T/S
Because the adhered chloride ions effect rusting of the rolling bearing, according to the present invention, the amount of chloride ions per unit area is limited to 0.2 ng/mm2 to 10 ng/mm2.
The antirust oil is not particularly limited if the antirust oil is one in which stickiness is hardly occurred so that workability is excellent and also an adhered amount thereof can be easily controlled, but, for example, antirust oil, which does not contain petrolatum, is preferably employed. In addition, to easily control an adhering amount of the antirust oil, viscosity of the antirust oil is preferably in a range of 10 cst to 60 cst.
Further, a method of adhering the antirust oil is not particularly limited if a film thickness thereof can be adjusted, but, for example, can include a centrifugal deoiling method, an air blowing method, or a vacuum heating method. In particular, to evenly adhere the antirust oil, the air blowing method is preferably employed.
An adhered amount of antirust oil is set to an average film thickness of 4.5 μm to 10 μm. If the average film thickness is less than 4.5 μm, it is difficult to keep antirust performance for a long time. In addition, because the antirust oil is reacted with grease to cause precipitation of crystals and thus to reduce an acoustic property, the reaction thereof with grease is likely to be occurred if the adhered amount of antirust oil exceeds an average film thickness of 10 μm.
The volatile corrosion inhibitor film may be a resin film, such as polyethylene film, containing an antirust agent, such as organic carboxylic acid amine salts, phosphoric acid amine salts, amine carbonate salts, heterocyclic amine salts, or the like. More specific examples of the antirust agents can include dicyclohexyl ammonium nitrite, dicyclohexyl ammonium caprylate, cyclohexylamine carbamate, cyclohexylamine laurate, diisopropyl ammonium nitrite, nitronaphthalene ammonium nitrite, ammonium benzoate, cyclohexylamine benzoate salts, dicyclohexylamine phosphate salts, and the like. To envelop the rolling bearing and to keep a pressure-reduced condition, the volatile corrosion inhibitor film in a form of a bag, as shown in FIGS. 1 to 5, is preferably used.
In addition, the volatile corrosion inhibitor film is preferably transparent, and by making the volatile corrosion inhibitor film transparent, stamping or the like can be checked in a packaged state. For example, when inspection results, such as dimensional differences, are directly imprinted on the bearing by a laser marker or the like, such inspection results can be checked without polluting the bearing. In particular, if being imprinted on an outer ring end surface, an inner ring end surface, an outer ring outer-diameter surface or the like, the inspection results can be more easily checked.
Further, the volatile corrosion inhibitor film and the bearing becomes a sealed state by reducing a pressure therebetween. Also, to keep such a pressure-reduced condition obtained by vacuum drawing, sealing, such as heat sealing, is performed.
By this packaging, rusting of the rolling bearing or adhering of foreign substances in the atmosphere thereto during storage or transport can be reliably prevented. In addition, cleaning or degreasing is not required, and also even when grease is provided therein, an effect of the antirust oil thereon is more reduced, thereby keeping a good lubricating ability.
The packaging described above may be performed in a state in which grease is provided in a bearing interior space defined by an inner ring, an outer ring and rolling elements, or in a state in which the grease is not provided. By packaging in a state in which the grease is provided, grease charge before use becomes unnecessary. Because the space between the volatile corrosion inhibitor film and the bearing is in a pressure-reduced condition, the packaging film enters a space between inner and outer rings in a concave manner to prevent grease from being flowed out even if it is vibrated during transport.
The present invention is not limited to types of rolling bearings, and for example, can be applied to packaging of an angular ball bearing 1 as shown in FIG. 2. Namely, the angular ball bearing 1 immediately after manufacturing is cleaned with a water substitution type cleaning liquid to remove chloride ions and sulfate ions and then after antirust oil is provided to adhered thereto at an average film thickness of 4.5 μm to 10 μm, is put in a bag made of a volatile corrosion inhibitor film 10, and the bag is vacuum drawn and sealed by heat sealing or the like. In the drawings, the reference numeral 11 denotes a sealing portion.
As shown in FIG. 3, the present invention can be applied in a similar manner in packaging a single-row cylindrical roller bearing 2.
Also, as shown in FIG. 4, an inner ring-side member of the single-row cylindrical roller bearing 2, which includes an inner ring 2A, cylindrical rollers 2B and a retainer 2C assembled together with each other, and an outer ring 2D thereof may be put in separate bags made of a volatile corrosion inhibitor film 10. By separately storing the inner ring-side member and the outer ring 2D, a sealed state thereof can be kept until immediately before the bearing is mounted, thereby more effectively inhibiting adhering of foreign substances in the atmosphere or rusting. When the inner ring-side member and the outer ring 2D are separately packaged in this way, packaging is performed in a state in which grease is not enclosed therein.
In addition, a double-row cylindrical roller bearing 3 may be packaged as shown in FIG. 5 and also an inner ring-side member of the double-row cylindrical roller bearing 3, which includes an inner ring 3A, cylindrical rollers 3B and a retainer 3C assembled together with each other, and an outer ring 3D thereof may be put and sealed in separate bags made of a volatile corrosion inhibitor film 10 as shown in FIG. 6.
EXAMPLES
Now, the present invention will be further described with reference to Test Examples, but the present invention is not limited by this.
Test Example 1 Antirust Performance Test
Angular ball bearings (inner diameter: 40 mm, outer diameter: 68 mm, and width: 15 mm) of a bearing number 7008CTYNDBLP4 immediately after assembly were prepared and was cleaned with a water substitution type cleaning liquid (“Aqua Solvent” produced by Aqua Chemical Co., Ltd.) to remove chloride ions and sulfate ions on a surface thereof. Next, lubricating oil (“ANTIRUST P-2810” produced by JX Nippon Oil & Energy Corporation; viscosity: 12 cst), which does not include petrolatum, was adhered as an antirust agent on the entire surface of the bearings by an air blowing method while varying an adhering amount thereof. Then, the bearings were put in bags made of a volatile corrosion inhibitor film (“BOSELON®” produced by Aicello Chemical Co., Ltd.) and the bags were sealed by heat sealing after vacuum drawing, thereby obtaining test samples. Meanwhile, an average film thickness (t) of the antirust oil was calculated by the following equation, where ΔS is an adhered amount of antirust oil and S is the entire surface of rolling members (an outer ring, an inner ring, a retainer and rolling elements) of the rolling bearing). Also, the adhered amount (ΔS) was obtained by measuring a difference (M) in weight before and after the antirust oil was adhered and dividing the difference by a specific gravity (ρ) of the antirust oil.
T=ΔS/S(ΔS=M/ρ)
Then, each test sample was left in a high temperature and high humidity environment of 50° C.-90% RH and periods of time until rust was occurred were compared. In the environment of 50° C.-90% RH, an effect of accelerating rusting by approximately 30 times is obtained as compared when samples were left at 20° C.-70% RH, which are the average temperature and humidity in Japan, and the equivalent numbers of years are shown in the figure. The results are shown in FIG. 7, but it can be found that, when the adhered amount of antirust oil is less than an average film thickness of 4.5 μm, antirust performance in a packed state is significantly decreased. From the results, it can be found that a favorable antirust performance can be kept for a long time by setting the adhered amount of antirust oil to an average film thickness of 4.5 μm or more.
Test Example 2 Grease Holding Ability Test
The test samples fabricated in Test example 1 were opened and then a bearing interior space defined by an inner ring, an outer ring and balls was charged with grease (MTE produced by NSK Ltd.) of 1.1 g (15% of the bearing interior space volume), thereby fabricating test bearings. Then, after rotating the bearings for 24 hours at conditions as described below, using a tester as shown in FIG. 8, grease residual rates were measured. Also, for comparison, the same bearings, on which cleaning and degreasing was performed and antirust oil was not adhered, were charged with grease to fabricate comparative test bearings, and grease residual rates were in the same manner. The term grease residual rate means a value which is obtained by subtracting a percentage, which is represented by a value obtained by dividing a difference between a bearing weight (M1) in a grease-charged condition before rotating and a bearing weight (M2) after rotating by a charged amount of grease (M3), from 100, and if the grease residual rate is low, a grease life is shortened.
Pre-pressure upon mounting: 120N
Number of revolutions: 10000 min−1 (dm·n=54×104)
Operation position: Vertical
Driving method: Belt driving
Cooling of an outer cylinder: No
The results are shown in FIG. 9, but it can be found that when the average film thickness is up to 10 μm, the test bearings have a grease residual rate of 97% on average as compared with the comparative test bearings having a grease residual rate of 99%, and therefore, the test bearings have a grease holding ability equivalent to those in a conventional using method in which grease charge is performed after cleaning and degreasing bearings. On the other hand, when the average film thickness is 15 μm or more, the grease residual rate tends to be decreased. From the results, it can be found that a grease holding ability equivalent to those in a conventional case, and thus a lubrication lifetime can be kept by setting the adhered amount of antirust oil to an average film thickness of 10 μm or less.
Test Example 3 Grease Precipitation Test
Test bearings prepared by cleaning deep groove ball bearings of a bearing number 6202 with a water substitution type cleaning agent, providing antirust oil to adhere at an average film thickness of 10 μm and then charging with grease (MTE or MTS produced by NSK Ltd., or ISOFLEX NBU 15 produced by NOK KLÜBER Co., Ltd.), and comparative test bearings prepared by cleaning and degreasing, and charging with the grease without providing the antirust oil to adhere, were fabricated, 10 units for each test bearing, 60 units in total.
Also, after each test bearing was placed in a constant temperature bath and then a heating cycle in which the temperature is changed from “0° C.→30° C.→60° C.” every few hours, was repeated 7 times, a noise count measurement was performed one time, and such a measurement was performed 4 times in total. Noise counts before and after heating cycles of bearings were measured using a noise tester mounted in a known anderon device (acoustic measurement device).
The results are shown in FIG. 10, but no significant difference between test bearings and comparative test bearings in initial noise count number and noise count number after heating cycles of 4 times was exhibited. From the results, it can be found that, by setting the adhered amount of antirust oil to an average film thickness of 10 μm or less, precipitation of crystals due to reaction of grease is not occurred.
Test Example 4 Bearing Temperature Rise Test
Test samples, in which the adhered amount of antirust oil in Test example 1 were adjusted to an average film thickness of 10 μm, were opened and then were charged with grease (MTE produced by NSK Ltd.) of 1.1 g (15% of the bearing interior space volume), thereby fabricating test bearings. Also, for comparison, comparative test bearings, which were charged with grease without adhering antirust oil after cleaning and degreasing, were fabricated. Then, each test bearing was rotated at conditions as described below, using the test apparatus used in Test example 2, and a temperature of the outer ring thereof at that time was measured.
Pre-pressure upon mounting: 120N
Number of revolutions: 12000 min−(dm·n=65×104)
Operation position: Vertical
Driving method: Belt drive
Cooling of outer cylinder: No
The results are shown in FIG. 11, but no significant difference between test bearings, on which the antirust oil was adhered at the average film thickness of 10 μm, and comparative test bearings in temperature rise characteristics was exhibited. From the results, it can be found that a temperature rise characteristics equivalent to those in a conventional case can be kept by setting the adhered amount of antirust oil to an average film thickness of 10 μm or less.
(Verification of Residual Chloride Ion Amount)
After rolling bearings were fabricated by typical grinding process and all surfaces thereof were ground, chloride ions adhered thereon were removed to become below a detection limit of an analyzer.
After such pretreatment, chloride ions were newly adhered by treatments shown in Table 1, and then an amount of chloride ions was measured. For the measurement, after rolling bearings were immersed in a bath, in which a predetermined amount of ultrapure water was filled, during 2.5 hours at a temperature of 80° C. so that chloride ions were dissolved, a liquid was collected from the bath and then an amount of chloride ions therein were measured by a ion chromatography analyzer, DX-120, and a separation column, IonPacAS12A (4 mm), which are produced by Dionex K.K. The measurement method was performed at conditions identical to those of Explanation FIG. 6 of JIS K0127. Qualification was performed for chloride ions, thereby calculating an amount per unit area. The results are shown in Table 1.
For rolling bearings, on which the same treatment was performed, a rusting acceleration test was performed. In the rusting acceleration test, after the antirust oil was applied to the rolling bearings at an average film thickness of 4.5 μm and the rolling bearings are left for thirty days in a high temperature and high humidity environment of 50° C., 90% RH, whether or not the surfaces of rolling bearings were rusted was verified. The results are shown in Table 1.
TABLE 1
Bearing surface Amount of
Samples treatment method chloride ions Rusting
1 Applying chloride ions by hand 13 ng/mm2 Yes
2 Cleaning Sample 1 to remove 5 ng/mm2 No
chloride ions
3 Applying artificial fingerprint 25 ng/mm2 Yes
liquid defined by JIS K 2246
4 Cleaning Sample 3 to remove 10 ng/mm2 No
chloride ions

As shown in Table 1, rusting can be prevented when an amount of chloride ions is 5 ng/mm2 to 10 ng/mm2.
In addition, assuming that an amount of chloride ions contained in a grinding water is 0.1 mg/L, which is a minimum defined in the Waterworks Law, it is believed that rolling bearings, which are typically ground and from which chloride ions does not removed, have chloride ions of few tens to few hundreds ng/mm2 adhered thereon, but when chloride ions are not removed, rusting cannot be prevented if the antirust oil has a thin film thickness of less than 4.5 μm.
From this test, it can be found that, when an amount of chloride ions, which have been adhered on rolling bearings after removing chloride ions therefrom, is set to 0.2 ng/mm2 to 10 ng/mm2, a favorable antirust performance can be obtained by setting a film thickness of the antirust oil to 4.5 μm or more (4.5 μm to 10 μm) as defined in the prevent invention.
Although the present invention has been described with referenced to the detailed and specific embodiments, it should be apparent to those skilled in the art that numerous changes and modifications can be made without departing the scope and spirit of the present invention.This application is based on Japanese Patent Application No. 2013-115810 filed on May 31, 2013, the entire content of which is incorporated herein by reference.
INDUSTRIAL APPLICABILITY
The present invention is suitable for storing and transporting machine tool bearings (in particular, machine tool spindle bearings).
DESCRIPTION OF REFERENCE SIGNS
    • 1 Angular ball bearing
    • 2 Single-row cylindrical roller bearing
    • 2A Inner ring
    • 2B Cylindrical roller
    • 2C Retainer
    • 2D Outer ring
    • 3 Double-row cylindrical roller bearing
    • 3A Inner ring
    • 3B Cylindrical roller
    • 3C Retainer
    • 3D Outer ring
    • 10 Volatile corrosion inhibitor film
    • 11 Sealing portion

Claims (6)

The invention claimed is:
1. A rolling bearing comprising an inner ring, an outer ring, and a plurality of rolling elements retained between the inner ring and the outer ring by a retainer in a rollable manner,
wherein antirust oil is provided to adhere, at an average film thickness of 4.5 μm to 10 μm, to an entire surface of the bearing from which chloride ions and sulfate ions are removed, the entire bearing is covered with a volatile corrosion inhibitor film, and a space between the volatile corrosion inhibitor film and the bearing is kept in a pressure-reduced condition.
2. The rolling bearing according to claim 1, wherein an amount of residual chloride ions adhered to the rolling bearing per unit area is 0.2 ng/mm2 to 10 ng·mm2.
3. The rolling bearing according to claim 1, A rolling bearing comprising an inner ring, an outer ring, and a plurality of rolling elements retained between the inner ring and the outer ring by a retainer in a rollable manner,
wherein antirust oil is provided to adhere, at an average film thickness of 4.5 μm to 10 μm, to an entire surface of the bearing from which chloride ions and sulfate ions are removed, the entire bearing is covered with a volatile corrosion inhibitor film, and a space between the volatile corrosion inhibitor film and the bearing is kept in a pressure-reduced condition,
wherein the entire bearing is covered with the volatile corrosion inhibitor film and the space between the volatile corrosion inhibitor film and the bearing is kept in the pressure-reduced condition, in a state in which a bearing interior space defined by the inner ring, the outer ring, and the rolling elements is charged with grease.
4. A method of packaging a rolling bearing after assembling the rolling bearing from bearing components, the method comprising:
after removing chloride ions and sulfate ions from an entire surface of the bearing, providing antirust oil to adhere thereto at an average film thickness of 4.5 μm to 10 μm, and covering the entire bearing with a volatile corrosion inhibitor film such that a space between the volatile corrosion inhibitor film and the bearing is kept in a pressure-reduced condition.
5. The method of packaging the rolling bearing according to claim 4, wherein the chloride ions and the sulfate ion are removed from the entire surface of the rolling bearing such that an amount of residual chloride ions adhered to the rolling bearing per unit area is 0.2 ng/mm2 to 10 ng/mm2.
6. The method of packaging the rolling bearing according to claim 4, A method of packaging a rolling bearing after assembling the rolling bearing from bearing components, the method comprising:
after removing chloride ions and sulfate ions from an entire surface of the bearing, providing antirust oil to adhere thereto at an average film thickness of 4.5 μm to 10 μm, and covering the entire bearing with a volatile corrosion inhibitor film such that a space between the volatile corrosion inhibitor film and the bearing is kept in a pressure-reduced condition,
wherein after the adhesion of the antitrust oil, a bearing interior space defined by an inner ring, an outer ring and rolling elements is charged with grease, and the entire bearing is covered with the volatile corrosion inhibitor film such that the space between the volatile corrosion inhibitor film and the bearing is kept in the pressure-reduced condition.
US16/442,851 2013-05-31 2013-10-03 Rolling bearing and its packaging method Active USRE48337E1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US16/442,851 USRE48337E1 (en) 2013-05-31 2013-10-03 Rolling bearing and its packaging method

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
JP2013-115810 2013-05-31
JP2013115810 2013-05-31
PCT/JP2013/076967 WO2014192177A1 (en) 2013-05-31 2013-10-03 Rolling bearing and method for wrapping same
US14/655,403 US9377057B2 (en) 2013-05-31 2013-10-03 Rolling bearing and its packaging method
US16/442,851 USRE48337E1 (en) 2013-05-31 2013-10-03 Rolling bearing and its packaging method

Publications (1)

Publication Number Publication Date
USRE48337E1 true USRE48337E1 (en) 2020-12-01

Family

ID=51988237

Family Applications (4)

Application Number Title Priority Date Filing Date
US14/655,403 Ceased US9377057B2 (en) 2013-05-31 2013-10-03 Rolling bearing and its packaging method
US16/442,851 Active USRE48337E1 (en) 2013-05-31 2013-10-03 Rolling bearing and its packaging method
US15/134,454 Ceased US9523391B2 (en) 2013-05-31 2016-04-21 Rolling bearing and its packaging method
US16/442,918 Active USRE48321E1 (en) 2013-05-31 2019-06-17 Rolling bearing and its packaging method

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US14/655,403 Ceased US9377057B2 (en) 2013-05-31 2013-10-03 Rolling bearing and its packaging method

Family Applications After (2)

Application Number Title Priority Date Filing Date
US15/134,454 Ceased US9523391B2 (en) 2013-05-31 2016-04-21 Rolling bearing and its packaging method
US16/442,918 Active USRE48321E1 (en) 2013-05-31 2019-06-17 Rolling bearing and its packaging method

Country Status (6)

Country Link
US (4) US9377057B2 (en)
EP (3) EP3096034A1 (en)
JP (2) JP6183378B2 (en)
CN (2) CN106870564B (en)
TW (1) TWI525018B (en)
WO (1) WO2014192177A1 (en)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9377057B2 (en) * 2013-05-31 2016-06-28 Nsk Ltd. Rolling bearing and its packaging method
DE102015209273A1 (en) * 2015-05-21 2016-11-24 Aktiebolaget Skf Method for maintenance and / or repair of a machine installation and for transporting a bearing arrangement
DE102015209272A1 (en) * 2015-05-21 2016-11-24 Aktiebolaget Skf Method for maintenance and / or repair of a machine installation and for transporting a bearing arrangement
CN106185049A (en) * 2016-08-29 2016-12-07 无锡三立轴承股份有限公司 The inner packing assembly of bearing
CN106144246A (en) * 2016-08-29 2016-11-23 无锡三立轴承股份有限公司 The antirust packaging bag of bearing
CN106185048A (en) * 2016-08-29 2016-12-07 无锡三立轴承股份有限公司 Bearing oil filling formula packaging bag
CN106241063A (en) * 2016-08-29 2016-12-21 无锡三立轴承股份有限公司 Bearing puncture type oil filling formula packaging bag
CN113042537A (en) * 2021-04-12 2021-06-29 内蒙古联晟新能源材料有限公司 Protection method for roller surface at-35 ℃ to +30 ℃ environment temperature

Citations (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4311738A (en) * 1980-05-27 1982-01-19 Dow Corning Corporation Method for rendering non-ferrous metals corrosion resistant
US4464275A (en) * 1980-03-07 1984-08-07 Koyo Seiko Co., Ltd. Rust preventive oil for a low frictional torque tapered roller bearing
JPH09286468A (en) 1996-04-22 1997-11-04 Oji Paper Co Ltd Pulp-molding packaging material
JP2003239090A (en) 2002-02-18 2003-08-27 Ntn Corp Rust preventive grease and rolling bearing
JP2004167602A (en) 2002-11-08 2004-06-17 Nittetsu Drum Kk Terminal processing method and device for galvanized steel sheet
JP2005221071A (en) 2004-01-06 2005-08-18 Toyota Motor Corp Connecting rod
US20050178500A1 (en) * 2003-12-15 2005-08-18 Polymer Group, Inc. Protective laminate and method for making same
JP2005350142A (en) 2004-05-13 2005-12-22 Nsk Ltd Shock absorbing material
US20060065285A1 (en) 2004-09-30 2006-03-30 Jatco Ltd. Rust prevention cleaning process apparatus and method thereof for a continuously variable transmission belt
EP1666634A1 (en) 2004-12-01 2006-06-07 Deft, Inc. Corrosion resistant conversion coatings
JP2006200658A (en) 2005-01-21 2006-08-03 Ntn Corp Rustproofing packing body and rustproofing packing method for bearing for machine tool
CN1853800A (en) 2005-04-20 2006-11-01 江苏小天鹅三江电器制造有限公司 Automatic oil coater of external ring of bearing
US7140491B2 (en) * 2003-10-15 2006-11-28 Tg Tools United Company Packaging for grouped similar items, including elongated items such as drill bits and the like
JP2006322604A (en) 2005-05-20 2006-11-30 Nsk Ltd Rolling bearing
US7235142B2 (en) 2002-01-04 2007-06-26 University Of Dayton Non-toxic corrosion-protection rinses and seals based on cobalt
JP2007191203A (en) 2006-01-20 2007-08-02 Nsk Ltd Covering method for roll bearing
JP2008025738A (en) 2006-07-21 2008-02-07 Nsk Ltd Packaging method and packaging element for bearing
JP2010258641A (en) 2009-04-23 2010-11-11 Nakagawa Special Steel Co Inc Antenna core, and method of manufacturing the same

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9377057B2 (en) * 2013-05-31 2016-06-28 Nsk Ltd. Rolling bearing and its packaging method

Patent Citations (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4464275A (en) * 1980-03-07 1984-08-07 Koyo Seiko Co., Ltd. Rust preventive oil for a low frictional torque tapered roller bearing
US4311738A (en) * 1980-05-27 1982-01-19 Dow Corning Corporation Method for rendering non-ferrous metals corrosion resistant
JPH09286468A (en) 1996-04-22 1997-11-04 Oji Paper Co Ltd Pulp-molding packaging material
US7235142B2 (en) 2002-01-04 2007-06-26 University Of Dayton Non-toxic corrosion-protection rinses and seals based on cobalt
JP2003239090A (en) 2002-02-18 2003-08-27 Ntn Corp Rust preventive grease and rolling bearing
JP2004167602A (en) 2002-11-08 2004-06-17 Nittetsu Drum Kk Terminal processing method and device for galvanized steel sheet
US7140491B2 (en) * 2003-10-15 2006-11-28 Tg Tools United Company Packaging for grouped similar items, including elongated items such as drill bits and the like
US20050178500A1 (en) * 2003-12-15 2005-08-18 Polymer Group, Inc. Protective laminate and method for making same
JP2005221071A (en) 2004-01-06 2005-08-18 Toyota Motor Corp Connecting rod
JP2005350142A (en) 2004-05-13 2005-12-22 Nsk Ltd Shock absorbing material
JP2006095472A (en) 2004-09-30 2006-04-13 Jatco Ltd Apparatus and method for rust prevention cleaning process for continuously variable transmission belt
US20060065285A1 (en) 2004-09-30 2006-03-30 Jatco Ltd. Rust prevention cleaning process apparatus and method thereof for a continuously variable transmission belt
EP1666634A1 (en) 2004-12-01 2006-06-07 Deft, Inc. Corrosion resistant conversion coatings
JP2006200658A (en) 2005-01-21 2006-08-03 Ntn Corp Rustproofing packing body and rustproofing packing method for bearing for machine tool
US20080139420A1 (en) 2005-01-21 2008-06-12 Hiroshi Takiuchi Rust Preventive Package Containing Bearing for Machine Tool and Rust Preventive Packaging Method
CN1853800A (en) 2005-04-20 2006-11-01 江苏小天鹅三江电器制造有限公司 Automatic oil coater of external ring of bearing
JP2006322604A (en) 2005-05-20 2006-11-30 Nsk Ltd Rolling bearing
JP2007191203A (en) 2006-01-20 2007-08-02 Nsk Ltd Covering method for roll bearing
JP2008025738A (en) 2006-07-21 2008-02-07 Nsk Ltd Packaging method and packaging element for bearing
JP2010258641A (en) 2009-04-23 2010-11-11 Nakagawa Special Steel Co Inc Antenna core, and method of manufacturing the same

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
Communication dated Mar. 4, 2016, issued by the State Intellectual Property Office of the People's Republic of China in counterpart Chinese Patent Application No. 201380003309.X.
Communication from the European Patent Office dated Apr. 28, 2016 in European Application No. 13 88 5525.9.
Communication issued Mar. 4, 2016, issued by the State Intellectual Property Office of the People's Republic of China in counterpart Chinese Patent Application No. 201380003309.X.
Search Report dated Dec. 10, 2013 issued by the International Searching Authority in counterpart International Patent Application No. PCT/JP2013/076967 (PCT/ISA/210).
Written Opinion dated Dec. 10, 2013 issued by the International Searching Authority in counterpart International Patent Application No. PCT/JP2013/076967 (PCT/ISA/237).

Also Published As

Publication number Publication date
US9377057B2 (en) 2016-06-28
CN106870564B (en) 2019-10-25
US20150354633A1 (en) 2015-12-10
USRE48321E1 (en) 2020-11-24
JPWO2014192177A1 (en) 2017-02-23
TW201444737A (en) 2014-12-01
JP2016153695A (en) 2016-08-25
US20160230812A1 (en) 2016-08-11
EP3096034A1 (en) 2016-11-23
CN106870564A (en) 2017-06-20
EP3460276A1 (en) 2019-03-27
US9523391B2 (en) 2016-12-20
TWI525018B (en) 2016-03-11
EP3006759A4 (en) 2016-05-25
CN104411989B (en) 2017-03-08
EP3006759A1 (en) 2016-04-13
WO2014192177A1 (en) 2014-12-04
JP6183378B2 (en) 2017-08-23
CN104411989A (en) 2015-03-11
EP3006759B1 (en) 2018-12-05

Similar Documents

Publication Publication Date Title
USRE48321E1 (en) Rolling bearing and its packaging method
US7819246B2 (en) Rust preventive package containing bearing for machine tool and and rust preventive packaging method
JP4853358B2 (en) Luminescence measuring device
KR100943368B1 (en) Guiding device
EP2767799A1 (en) Method for measuring threaded element at tube end
US20090290824A1 (en) Rolling bearing and full complement rolling bearing
JP2006258473A (en) Bearing lifetime estimating method of roller bearing
JP2006322604A (en) Rolling bearing
JP2004239443A (en) Rolling bearing
JPWO2013118202A1 (en) Rolling bearing and film transport device
WO2013136379A1 (en) Rolling bearing and film conveyor
CN219842416U (en) Waste water impurity detection device
JP2003314571A (en) Lubricating device for roller bearing
US20200124101A1 (en) In Situ Lubrication of Thin Section Bearings
JP4727104B2 (en) SEALING DEVICE AND TREATING DEVICE USING THIS SEALING DEVICE
CN115839778A (en) Analysis method for judging service temperature of working surface of bearing under lubricating condition
EP2517980A1 (en) Lined device, method for manufacturing a lined device, lining inspection method and composition for forming a lining inspection coating
KR20120044149A (en) Oil pollution preventing apparatus of straighting roll and steel sheet leveling equipment the same
WO2017001627A1 (en) Use of grease compositions
JP2016109152A (en) Rolling device
JP2004354188A (en) Inner surface treatment method of container

Legal Events

Date Code Title Description
FEPP Fee payment procedure

Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 8TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1552); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Year of fee payment: 8