WO2017043445A1 - Palier à roulement pour environnements à température extrêmement basse - Google Patents

Palier à roulement pour environnements à température extrêmement basse Download PDF

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Publication number
WO2017043445A1
WO2017043445A1 PCT/JP2016/076014 JP2016076014W WO2017043445A1 WO 2017043445 A1 WO2017043445 A1 WO 2017043445A1 JP 2016076014 W JP2016076014 W JP 2016076014W WO 2017043445 A1 WO2017043445 A1 WO 2017043445A1
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WO
WIPO (PCT)
Prior art keywords
rolling bearing
cage
protrusion
retainer
bearing
Prior art date
Application number
PCT/JP2016/076014
Other languages
English (en)
Japanese (ja)
Inventor
石田　昌幸
Original Assignee
Ntn株式会社
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
Application filed by Ntn株式会社 filed Critical Ntn株式会社
Publication of WO2017043445A1 publication Critical patent/WO2017043445A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/04—Shafts or bearings, or assemblies thereof
    • F04D29/046—Bearings
    • F04D29/049—Roller bearings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/02—Selection of particular materials
    • F04D29/026—Selection of particular materials especially adapted for liquid pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D7/00—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts
    • F04D7/02—Pumps adapted for handling specific fluids, e.g. by selection of specific materials for pumps or pump parts of centrifugal type
    • 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
    • F16C19/04—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly
    • F16C19/06—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly with a single row or balls
    • 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
    • F16C33/38—Ball cages
    • 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

Definitions

  • the present invention relates to a rolling bearing for a cryogenic environment that is used at a cryogenic temperature, such as a bearing of a submerged pump that transports a liquefied gas in a cryogenic state such as liquefied natural gas.
  • a rolling bearing used in a normal temperature environment requires a rolling element to be rotatably held between an inner ring and an outer ring and requires liquid lubrication with a lubricating oil or the like.
  • liquid lubrication with a normal lubricating oil or the like cannot be expected.
  • rolling bearings for cryogenic environments are liable to deteriorate in strength and durability due to shrinkage and deformation of parts, and are required to withstand such severe use conditions.
  • liquefied natural gas which is a typical example of a cryogenic liquefied gas, has methane as a main component and has a physical property that does not liquefy unless it is ⁇ 161.5 ° C. (about ⁇ 162 ° C.) or lower under normal pressure.
  • examples of liquefied gas used in a liquefied state such as a refrigerant, a heat medium, and a filling gas include nitrogen and helium.
  • the environmental temperature is not only in the above-mentioned environment where liquid gas exists, but also in a high altitude space beyond the stratosphere far from the surface of the earth, and in a far away space. Since the temperature is about 50 to ⁇ 270 ° C., similar characteristics are required for rolling bearings for cryogenic environments used in such artificial satellites and spacecraft.
  • an outer ring and an inner ring are made of martensitic stainless steel, a rolling element is made of ceramic, and a cage is made of a fluororesin. (Patent Document 1 below).
  • the conventional rolling bearing for the cryogenic environment described above is not easy to sufficiently supply the solid lubricating component to the rolling elements and the raceway surfaces of the inner and outer rings in the cryogenic environment, and it is not possible to pass the time from the fluororesin cage. Therefore, it has been difficult to supply a sufficient amount of lubricating components to the raceway surface.
  • the problem of the present invention is to solve the above-mentioned problems and to sufficiently supply the solid lubricating component to the raceway surfaces of the rolling elements and the inner and outer rings when used in a cryogenic environment.
  • a rolling bearing for a cryogenic environment capable of supplying a sufficient amount of a lubricating component to the raceway surface even in a rotating state in which a constant load acts in the axial direction.
  • the cage in the rolling bearing provided with a cage made of a fluororesin-based molded body that rotatably holds a plurality of balls between the inner ring and the outer ring, the cage is A plurality of separator-type cage pieces obtained by dividing a ring-like cage in the circumferential direction and integrally connected by a bearing side plate.
  • the cage piece includes an inner ring or an outer ring, or a raceway surface of these two wheels.
  • the protrusion provided on the cage piece made of a fluororesin-based molded body protrudes at a predetermined height toward the raceway surface to the raceway surface. Since the contact is possible, the fluororesin of the cage not only moves to the raceway surface via the ball, but also moves directly to the raceway surface of the inner ring or the outer ring or both wheels and lubricates.
  • the direct supply of the fluororesin excellent in lubricity at the cryogenic temperature as described above to the raceway surface by the cage piece is a ball that rolls the axial load received by the inner ring and the outer ring by the protrusion.
  • the contact points between the raceway surfaces of the inner and outer rings and the ball transmitted to the ball are protrusions that project to a height that can be contacted toward the movement path on the raceway surface accompanying the rolling of the contact points. Therefore, it is preferable to supply the fluororesin efficiently to a specific portion of the raceway surface where the lubricating component tends to be insufficient.
  • protrusions are one or more line-shaped protrusions extending in the circumferential direction of the separator-type cage piece, thereby limiting the sliding contact area between such protrusions and the raceway surface, and excessively This makes it possible to efficiently supply fluororesin to the raceway surface while avoiding unnecessary contact.
  • such a protrusion is a protrusion having a circular curved surface that matches the raceway surface at the top, the top of the protrusion can be brought into contact with the raceway as much as possible. It is preferable that much fluororesin can be efficiently supplied to the raceway surface.
  • the separator-type cage piece in the rolling bearing is provided with a protrusion that protrudes toward the raceway surface of the inner ring or the outer ring or both the wheels, so that the rolling bearing rotates.
  • the fluororesin of the cage not only moves to the raceway surface via the ball, but also moves directly to the raceway surface of the inner ring or outer ring or both of these wheels for lubrication.
  • Fluorine resin can be sufficiently supplied to the raceway surfaces of the rolling elements and the inner and outer rings, and a sufficient amount of lubricating components can be supplied to the raceway surface even in the rotating state of the bearing in which a constant load acts in the axial direction. There is an advantage that it becomes a rolling bearing for a cryogenic environment.
  • the first embodiment is a deep groove ball bearing in which a cage 4 made of a fluororesin-based molded body that rotatably holds a plurality of balls 3 is provided between an inner ring 1 and an outer ring 2.
  • the retainer 4 includes a plurality of separator-type retainer pieces 5 obtained by dividing the ring-shaped retainer 4 in the circumferential direction on a ring-shaped bearing side plate 6 with screws 7.
  • the cage piece 5 protrudes toward the raceway surface 2a on the inner peripheral side of the outer ring 2 and extends in the circumferential direction of the cage piece 5 in two rows of linear protrusions 5a. Is a rolling bearing for a cryogenic environment provided at a height that allows contact with the raceway surface 2a.
  • the ball bearing A of the embodiment is made of a material that can withstand use in a cryogenic environment.
  • the base material of the inner ring 1 and the outer ring 2 is martensitic stainless steel or high-speed tool steel. It is a hard steel material with excellent wear resistance.
  • martensitic stainless steel include SUS403, SUS420, and SUS440C.
  • high-speed tool steel include M50, a high-speed steel according to the American Iron and Steel Institute AISI standard, and SKH4, a Japanese industrial standard.
  • a hard film mainly composed of diamond-like carbon (hereinafter abbreviated as DLC) having a Vickers hardness (Hv) of about 1000 to 4000 is provided on the surfaces of the inner ring 1 and the outer ring 2.
  • DLC diamond-like carbon
  • Hv Vickers hardness
  • DLC has an intermediate structure in which diamond and graphite are mixed, and can be formed with the same hardness as diamond.
  • a known film forming method such as a physical vapor deposition method such as sputtering or ion plating, a chemical vapor deposition method, or an unbalanced magnetron sputtering (UBMS) method can be employed.
  • UBMS unbalanced magnetron sputtering
  • a first intermediate layer mainly composed of a metal-based material is formed on the base material, and the first intermediate layer is superimposed on the first intermediate layer. It is preferable that the second intermediate layer having a composition gradient in which the composition ratio of carbon is increased as it gets closer.
  • the DLC gradient layer can be obtained by forming a hard film by using a graphite target in the UBMS method while increasing the bias voltage with respect to the substrate continuously or stepwise.
  • the hardness of the hard coating is more preferably (Hv) 1000 to 3000.
  • the hardness of the hard film is more preferably (Hv) 1000 to 1500 in view of the low coefficient of friction.
  • the material of the ball (sphere) 3 is preferably made of ceramics in terms of good wear resistance and excellent transferability of fluororesin, and the type of ceramics is not particularly limited, but silicon nitride, zirconia Although a ceramic based, silicon carbide based or alumina based ceramic can be prepared, for example, a rolling element made of a silicon nitride based ceramic is preferable because it is particularly hard and excellent in wear resistance.
  • the cage 4 used in the present invention employs a molded body made of a material mainly composed of a fluororesin such as polytetrafluoroethylene (PTFE). This is because it is preferable for exhibiting good and stable solid lubricity by transferring a solid lubricant to the surface of the rolling element even at an extremely low temperature.
  • PTFE polytetrafluoroethylene
  • the retainer 4 is a short cylindrical shape having an appropriate thickness, that is, a general ring-shaped retainer main body, which is divided into a plurality of separators in which the number of gaps is equal to the width of the gap between the balls 3 by dividing the main body in the circumferential direction. It is composed of a container piece 5 and is integrally connected by tightening and fixing to an annular bearing side plate 6 formed with a hole 6a for fixing them at the position of the gap.
  • each cage piece 5 is connected to the inner ring 1 and the outer ring 2 together with the balls 3. After being assembled in between, it is fixed with screws 7 through the bearing side plate 6.
  • the raceway surface 2a of the outer ring 2 or the raceway of the inner ring 1 respectively.
  • Two rows of line-shaped protrusions 5a projecting upright toward the surface 1a and extending along the circumferential direction of the cage piece 5 are provided at a height that allows contact with the track surface 2a.
  • the number of the line-shaped protrusions 5a may be one row in addition to the illustration, and may be provided in three or more rows.
  • the protrusion 5a provided on the cage piece 5 made of a fluororesin-based molded body protrudes at a predetermined height toward the raceway surface 1a or the raceway surface 2a or both. Therefore, the fluororesin of the cage 5 is not only transferred to the raceway surfaces 1a and 2a via the balls 3, but directly to the inner race 1 or the outer race 2 or the raceway surfaces 1a and 2a of these two wheels. Transfer and lubricate.
  • each component of the ball bearing A tends to lack a lubricating component, self-lubricating properties are sufficiently exerted, and particularly a sufficient amount of lubrication is applied to a bearing in which a constant load is applied in the axial direction.
  • the component is supplied to the raceway surface.
  • positioning and form of the protrusion 5c shown in FIG. 4 is rolling when the load (indicated by an arrow in the figure) received by the inner ring 1 and the outer ring 2 is a load opposite in the axial direction.
  • the load transmitted to the ball 3 passes through a pair of contact points (a 1 , b 1 or a 2 , b 2 ) facing the radial direction of the ball 3 from the raceway surfaces of the inner ring 1 and the outer ring 2.
  • the dashed-dotted line in FIG. 4 has shown the action line of the load which acts on the radial direction of a ball
  • Such embodiment is preferred because, in the moving path of the orbital plane 1a of the contact point between the raceway surface 1a and the ball 3 (a 1, b 1 or a 2, b 2), since the focus load is applied, Fluororesin-based lubricants tend to be in short supply, but by supplying a large amount of lubricants to such areas, it is possible to efficiently supply lubricating components to the raceway surface and stabilize the rotation even in a cryogenic environment. This is because it can be a rolling bearing.
  • the shape of the protrusions 5a and 5c is not limited to one or more linear protrusions extending in the circumferential direction of the cage pieces 5 and 5 'shown in FIGS. 1 to 4, for example, as shown in FIG.
  • the protrusion 5d may be a semi-cylindrical circular curved surface that matches the circular groove-like portion of the raceway surface, or other well-known protrusion (not shown).
  • Such protrusions 5d and other protrusions can also be provided on either the outer diameter side or the inner diameter side of the cage piece 5 or on both sides.
  • the specific use of the rolling bearing for the cryogenic environment according to the present invention may be a rolling bearing of a pump for a liquefied gas, or a rolling bearing used for supporting or driving a satellite antenna. good.
  • the rolling bearing When the application of the rolling bearing is a pump for liquefied gas, it may be a submerged pump for liquefied natural gas (LNG), but in that case, since the rolling bearing directly contacts the cryogenic LNG, the inner and outer rings and rolling elements of the present invention have a remarkable effect of becoming a rolling bearing for a cryogenic environment excellent in durability that withstands long-term use and does not deteriorate wear resistance and lubricity.
  • LNG liquefied natural gas
  • the submerged pump for liquefied natural gas (LNG) exhibits airtightness in a pot (pressure vessel) 8 by immersing the entire pump in the liquid.
  • a pot pressure vessel 8 by immersing the entire pump in the liquid.
  • the pot 8 is opened with the LNG suction port 11 facing outward, and has a discharge port 12 leading to an external pipe (not shown).
  • the motor 13 mounted in the pot 8 supports the upper and lower sides of the motor shaft 10 rotated by an external power source with the ball bearing A of the embodiment shown in FIG.
  • a plurality of stages of impellers 14 are attached to the rotating pump shaft 9.
  • a downward load is applied to the inner ring from the motor shaft 10, and the outer ring is fixed to a peripheral base, so that the inner ring and the outer ring are loaded in opposite directions in the axial direction. It is used in the state where it takes.
  • the flow path in the illustrated apparatus of the pump is such that the LNG flowing from the suction port 11 into the pot 8 along the inner surface of the pot 8 by the impeller 14 that rotates integrally with the pump shaft 9 by the driven motor 13. It flows downward and flows into the discharge port 12 from the pipe 16 inside the cylindrical inner wall 15 arranged around the impeller 14, and is sucked in from the lowermost portion of the multistage impeller 14.
  • the other pipe 17 inside the cylindrical inner wall 15 flows in the motor 13 as a lubricating liquid, lubricates and cools the ball bearing A, joins the downward flow along the inner side surface of the pot 8, and again multistage. Is sucked from the tip of the impeller 14.
  • the ball bearing A used in this way holds ceramic balls with a PTFE cage, and a hard coating mainly composed of diamond-like carbon having a predetermined hardness is provided on the inner ring and outer ring base material surfaces. It is preferable that the raceway surface and the rolling element are extremely less worn, lubricated and cooled by LNG, and the load applied to the inner ring and the outer ring tends to cause insufficient lubrication in a part of the raceway surface. It is a rolling bearing that can withstand long-term use in a cryogenic environment and does not deteriorate in wear resistance and lubricity over time.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Rolling Contact Bearings (AREA)

Abstract

La présente invention concerne un palier à roulement pour des environnements à température extrêmement basse, comprenant un palier à bille à rainure profonde (A) doté d'un dispositif de retenue (4) composé d'un corps moulé en fluororésine, le dispositif de retenue (4) étant obtenu par une pluralité de pièces de retenue de type séparateur (5) qui divisent, dans la direction circonférentielle, le dispositif de retenue (4) ayant une partie principale en forme d'anneau reliée d'un seul tenant à une plaque côté palier annulaire (6) par ancrage avec des vis (7) et la pièce de retenue (5) étant pourvue d'une saillie linéaire (5a) qui fait saillie vers une face de piste (2a) sur le côté circonférentiel interne d'une bague externe (2) et s'étendant le long de la direction circonférentielle de la pièce de retenue (5), à une hauteur qui permet un contact avec la face de piste. Du fait que la saillie (5a) prévue sur la pièce de retenue (5) peut entrer en contact avec la face de piste (2a), la fluororésine lubrifie efficacement la face de piste (2a) en étant transférée par le biais d'une bille (3).
PCT/JP2016/076014 2015-09-10 2016-09-05 Palier à roulement pour environnements à température extrêmement basse WO2017043445A1 (fr)

Applications Claiming Priority (2)

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JP2015-178385 2015-09-10
JP2015178385 2015-09-10

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114576271A (zh) * 2022-03-16 2022-06-03 洛阳Lyc轴承有限公司 一种液氧泵主轴轴承用金属加强型保持架及其制备工艺

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0221027A (ja) * 1988-07-07 1990-01-24 Toshiba Corp ころがり軸受
JPH04272510A (ja) * 1991-02-27 1992-09-29 Yaskawa Electric Corp 転がり軸受用保持器
JPH06337016A (ja) * 1993-05-28 1994-12-06 Nippon Seiko Kk 耐食性転がり軸受
JP2011094719A (ja) * 2009-10-30 2011-05-12 Nsk Ltd 玉軸受

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0221027A (ja) * 1988-07-07 1990-01-24 Toshiba Corp ころがり軸受
JPH04272510A (ja) * 1991-02-27 1992-09-29 Yaskawa Electric Corp 転がり軸受用保持器
JPH06337016A (ja) * 1993-05-28 1994-12-06 Nippon Seiko Kk 耐食性転がり軸受
JP2011094719A (ja) * 2009-10-30 2011-05-12 Nsk Ltd 玉軸受

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114576271A (zh) * 2022-03-16 2022-06-03 洛阳Lyc轴承有限公司 一种液氧泵主轴轴承用金属加强型保持架及其制备工艺

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