WO2023008313A1 - 玉軸受 - Google Patents

玉軸受 Download PDF

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Publication number
WO2023008313A1
WO2023008313A1 PCT/JP2022/028375 JP2022028375W WO2023008313A1 WO 2023008313 A1 WO2023008313 A1 WO 2023008313A1 JP 2022028375 W JP2022028375 W JP 2022028375W WO 2023008313 A1 WO2023008313 A1 WO 2023008313A1
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WO
WIPO (PCT)
Prior art keywords
bearing
ball
ball bearing
lubricating oil
balls
Prior art date
Application number
PCT/JP2022/028375
Other languages
English (en)
French (fr)
Japanese (ja)
Inventor
武仁 櫻井
翔平 深間
悠介 鈴木
吉稀 竹田
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
Priority to CN202280052208.0A priority Critical patent/CN117751250A/zh
Priority to KR1020247005425A priority patent/KR20240038746A/ko
Publication of WO2023008313A1 publication Critical patent/WO2023008313A1/ja

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    • 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
    • F16C33/32—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
    • F16C33/41—Ball cages comb-shaped
    • 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
    • F16C33/44—Selection of substances
    • 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
    • F16C33/58—Raceways; Race rings
    • 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
    • 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
    • F16C33/72—Sealings
    • F16C33/76—Sealings of ball or roller bearings
    • F16C33/78—Sealings of ball or roller bearings with a diaphragm, disc, or ring, with or without resilient members
    • 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
    • F16C33/72—Sealings
    • F16C33/76—Sealings of ball or roller bearings
    • F16C33/78—Sealings of ball or roller bearings with a diaphragm, disc, or ring, with or without resilient members
    • F16C33/784—Sealings of ball or roller bearings with a diaphragm, disc, or ring, with or without resilient members mounted to a groove in the inner surface of the outer race and extending toward the inner race
    • 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
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
    • F16J15/3204—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings with at least one lip

Definitions

  • This invention relates to ball bearings.
  • Ball bearings which are superior in low-torque properties, are employed as bearings for supporting the rotating shafts of the drive motors or transmissions.
  • the balls and the inner and outer races, which are the constituent elements of the ball bearing are generally made of steel, and are subjected to various heat treatments and surface modification treatments for damage prevention as necessary.
  • caps such as seals and shields are applied to the ball bearings. Installation of components is being carried out.
  • a typical contact seal has a ring-shaped seal lip made of an elastic material such as rubber.
  • a mating part such as a bearing ring or a slinger that rotates relative to the seal in the circumferential direction as the bearing rotates is formed with a seal sliding surface that slides in the circumferential direction on the seal lip.
  • the seal lip and the seal sliding surface are in sliding contact all around, microscopically accompanied by a solid contact area.
  • the drag resistance (seal torque) of the seal lip contributes to the temperature rise of the bearing torque and ball bearings.
  • a non-contact seal or shield is used as the cap member, it is possible to eliminate the seal torque, but the size of the non-contact gap between the seal member and the mating part must be adjusted to prevent the intrusion of foreign matter of a specified particle size. Error management is difficult.
  • the sealed ball bearing disclosed in Patent Document 1 has a plurality of protrusions in which the seal lips are arranged in the circumferential direction, and the plurality of protrusions are located between adjacent protrusions in the circumferential direction.
  • the seal lip and the seal sliding surface are lubricated by a lubricating oil film that is dragged through the gap between the protrusion and the seal sliding surface as the bearing rotates. It is designed to
  • the sealed ball bearing disclosed in Patent Document 1 can cope with high-speed operation while preventing the intrusion of foreign matter of a predetermined particle size that may cause early damage to the bearing. Torque can be significantly reduced.
  • the ball bearing is provided with a cap member such as a seal or shield that suppresses the inflow of lubricating oil into the bearing, it is effective in reducing stirring resistance. concerns will increase.
  • the problem to be solved by the present invention is to improve the low torque property of a ball bearing that supports a rotating shaft included in a vehicle driving motor or a transmission connected to a vehicle driving motor and prevent damage to the ball bearing. It is to make prevention compatible.
  • the present invention provides a ball bearing for supporting a rotating shaft included in a vehicle driving motor or a transmission connected to the vehicle driving motor, and includes an inner bearing ring and an outer bearing ring. a bearing ring, a plurality of balls interposed between the inner and outer bearing rings, a retainer that holds the plurality of balls, and a cap member that suppresses the inflow of lubricating oil from the outside of the bearing into the inside of the bearing;
  • the ball is made of a material different from steel, and the internal bearing clearance during operation is set to a value greater than 0 ⁇ m at 80°C or higher, and the kinematic viscosity of the lubricating oil supplied to the bearing at 100°C is 7. 0 mm 2 /s or less was adopted.
  • the vehicle drive motor in the present invention refers to an electrical device that converts electrical energy and outputs rotation that serves as a vehicle drive source, and an electrical device that converts input rotation into electrical energy during regenerative braking of the vehicle. It means what corresponds to at least one.
  • the transmission in the present invention means a device that converts the input rotational speed and transmits it to the output side, and a continuously variable transmission that can continuously change the speed conversion ratio (reduction ratio, gear ratio),
  • the concept includes a fixed-ratio transmission in which the speed conversion ratio is fixed, and the fixed-ratio transmission includes what is called a speed reducer or a speed increaser that has only one type of speed conversion ratio. included.
  • kinematic viscosity in this invention is the value in the measurement in accordance with the "kinematic viscosity test method" specified in JIS K 2283: 2000 "Crude oil and petroleum products-kinematic viscosity test method and viscosity index calculation method”. means.
  • the ball is made of ceramics. Since the ceramic ball is an insulator, electrolytic corrosion does not occur in the elastic contact area. Furthermore, the use of ceramic balls reduces the loss (elastic hysteresis, differential slip) in the elastic contact area between the ball and raceway compared to steel balls. can be reduced.
  • the cross-sectional shape of the raceway grooves of the inner and outer races is arcuate with a diameter not greater than 1.1 times the diameter of the ball.
  • Such an arc shape is suitable for reducing the bearing torque while suppressing the surface pressure in the elastic contact area between the ball and the bearing ring.
  • the cap member is attached to one of the inner and outer races, and the cap member is a seal that slides in the circumferential direction on a seal sliding surface provided on the other of the inner and outer races.
  • the sealing lip has a plurality of protrusions arranged in the circumferential direction, and the plurality of protrusions communicate between the protrusions adjacent in the circumferential direction to the inside and the outside of the bearing. A gap is formed, and the seal lip and the seal sliding surface are brought into a fluid lubrication state by an oil film of lubricating oil that is dragged from the gap between the protrusion and the seal sliding surface as the bearing rotates.
  • the retainer may be a crown-shaped retainer made of synthetic resin.
  • Such a retainer is lighter and more self-lubricating than a corrugated retainer made of steel plate, and is therefore suitable for reducing bearing torque.
  • synthetic resin is a concept that includes fiber reinforced resin.
  • the synthetic resin comprises a fiber-reinforced polyamide resin or a fiber-reinforced polyphenylene sulfide resin.
  • the crown retainer has good deformation resistance against centrifugal force, and is suitable for high-speed rotation.
  • grease is enclosed as an initial lubricant inside the bearing, and the amount of the grease enclosed is preferably 5 to 20% by volume of the total space volume of the bearing. By doing so, it is possible to suppress the agitation resistance of the grease while suppressing insufficient lubrication in the initial stage of operation of the ball bearing.
  • At least one of nitrile rubber, acrylic rubber, fluororubber, cold-rolled steel plate, and stainless steel plate may be used as the material of the cap member.
  • the cap member can be manufactured from a material commonly used as a material for seals and shields.
  • the balls are preferably made of nitride ceramics.
  • Nitride-based ceramics are suitable because they are generally excellent in mechanical properties such as light weight, high strength, and high toughness.
  • FIGS. 1 to 6 of the accompanying drawings A sealed bearing according to a first embodiment as an example of the present invention will be described with reference to FIGS. 1 to 6 of the accompanying drawings.
  • This ball bearing 1 shown in FIG. a retainer 5 for holding the plurality of balls 4, and cap members 6 attached to both sides of one of the inner and outer bearing rings 3. As shown in FIG.
  • This ball bearing 1 is a double-sealed deep groove ball bearing.
  • the direction along the bearing center axis (not shown, hereinafter the same) of the ball bearing 1 will be referred to as the "axial direction”.
  • a direction orthogonal to the axial direction is called a “radial direction”.
  • the direction along the circumference around the center axis of the bearing is referred to as the "circumferential direction”.
  • the bearing center axis is the center axis of the inner bearing ring 2 which is the rotating ring.
  • FIG. 1 shows a cross section of an imaginary plane containing the bearing central axis.
  • the axial direction corresponds to the horizontal direction in FIG. 1
  • the radial direction corresponds to the vertical direction in FIGS.
  • the inner bearing ring 2 is made of a steel annular member having a raceway groove 2a that contacts the balls 4 on the outer peripheral side.
  • the inner bearing ring 2 is fitted to the rotating shaft S at its inner circumference.
  • the outer bearing ring 3 consists of a steel annular member having a raceway groove 3a in contact with the balls on the inner peripheral side.
  • the outer bearing ring 3 is attached to a member such as a housing, a gear, or the like that bears the load from the rotating shaft.
  • the rotating shaft S is included in a vehicle driving motor or a transmission connected to the vehicle driving motor. They are the input shaft for input, the output shaft for rotational output, and the intermediate transmission shaft.
  • a vehicle driving motor 20, a transmission 30 connected to the vehicle driving motor 20 , and rotation shafts S20, S31 , S32 included in the vehicle driving motor 20 or the transmission 30 are supported.
  • An example of a rotation transmission device including a ball bearing 1 is shown.
  • the illustrated rotation transmission device is incorporated in a vehicle drive system.
  • the transmission 30 includes a plurality of rotating shafts S 31 to S 33 , gears G1 to G3 provided on each of these rotating shafts S 31 to S 33 , and a plurality of ball bearings 1 supporting the rotating shafts S 31 to S 32 .
  • the rotating shaft S31 and the rotating shaft S20 of the vehicle drive motor 20 rotate together.
  • the rotating shaft S33 is supported by a plurality of tapered roller bearings.
  • the transmission 30 serves as a gear reducer that reduces the rotation input from the rotation shaft S20 to the rotation shaft S31 and outputs the rotation from the rotation shaft S33 .
  • the transmission 30 serves as a gear speed increaser that speeds up the rotation input to the rotating shaft S33 from the traveling wheel side and outputs it from the rotating shaft S31 .
  • the bearing internal clearance during operation of the ball bearing 1 shown in FIG. 2 is set to a value greater than 0 ⁇ m at 80° C. or higher.
  • the bearing internal clearance refers to the amount of movement when one of the inner and outer bearing rings is fixed and the other is moved. When the other is moved in the radial direction, it is called the radial internal clearance, and when it is moved in the axial direction, it is called the axial internal clearance.
  • the temperature of all the ball bearings 1 is 80° C. or higher, both the radial internal clearance and the axial internal clearance of the ball bearing 1 continue to exceed 0 ⁇ m.
  • the ball 4 shown in FIG. 1 consists of a spherical rolling element that revolves while rotating between the inner and outer raceway grooves 2a and 3a.
  • the ball 4 is made of a material different from steel.
  • Nitride-based ceramics Si 3 N 4
  • each of the inner and outer raceway grooves 2a, 3a corresponds to the generatrix shape of each of the raceway grooves 2a, 3a on the imaginary plane shown in FIG.
  • the cross-sectional shape of the raceway groove 2a is arcuate with a diameter not greater than 1.1 times the diameter of the ball 4 .
  • the cross-sectional shape of the raceway groove 3a is also arcuate with a diameter not greater than 1.1 times the diameter of the ball 4 .
  • the retainer 5 consists of an annular bearing component that keeps a plurality of balls 4 interposed between the inner and outer raceway grooves 2a, 3a at a predetermined circumferential interval.
  • the cage 5 in the illustrated example is a corrugated cage formed by coupling a pair of steel plate corrugated press parts.
  • the cap member 6 separates the outside of the ball bearing 1 and the inside 7 of the bearing.
  • the bearing interior 7 is an annular space formed over the entire circumference between the inner and outer races 2 and 3 .
  • Lubricating oil (not shown) is supplied to the ball bearing 1 from the outside of the bearing.
  • the lubricating method include a splashing method in which lubricating oil is applied to the ball bearing 1 and an oil bath method in which the lower portion of the ball bearing 1 is immersed in lubricating oil.
  • Grease G (indicated by a dot pattern in FIG. 1) is enclosed in the bearing interior 7 as an initial lubricant.
  • the cap member 6 prevents foreign matter from entering the bearing interior 7 from the outside of the bearing, lubricating oil supplied to the ball bearing 1 from the outside of the bearing flowing into the bearing interior 7, and grease G from leaking to the outside of the bearing. Suppress.
  • the cap member 6 does not liquid-tightly seal the bearing interior 7 from the bearing exterior.
  • a seal groove 3b for holding the cap member 6 is formed in one of the inner and outer races 3.
  • the cap member 6 is attached to the bearing ring 3 by press-fitting the peripheral portion on the bearing ring 3 side into the seal groove 3b.
  • the illustrated cap member 6 has a metal core 8 made of a metal plate and a seal lip 9 made of an elastic material.
  • the cored bar 8 is made of a pressed part.
  • the elastic material include a vulcanized rubber material, an elastomer equivalent to a rubber material, and the like.
  • rubber materials include nitrile rubber (NBR), acrylic rubber (ACM), and fluororubber (FKM).
  • NBR nitrile rubber
  • ACM acrylic rubber
  • FKM fluororubber
  • a cold-rolled steel plate and a stainless steel plate are mentioned, for example.
  • a seal sliding surface 2 b that slides on the seal lip 9 in the circumferential direction is formed on the inner and outer bearing rings 2 opposite to the inner and outer bearing rings 3 .
  • the seal sliding surface 2b has a cylindrical surface along the circumferential direction.
  • the seal lip 9 has a plurality of protrusions 9a arranged in the circumferential direction. These plurality of protrusions 9a create gaps 10 between adjacent protrusions 9a in the circumferential direction that communicate with the inside 7 of the bearing and the outside.
  • the seal lip 9 and the seal sliding surface 2b are provided so as to be fluidly lubricated by an oil film of lubricating oil (indicated by dots in FIG. 3) drawn between the seal lip 9 and the seal sliding surface 2b.
  • the cap member 6 allows lubricating oil to flow between the inside 7 of the bearing and the outside through a gap 10 that can prevent foreign matter of a predetermined particle size from entering. Therefore, a thick oil film is formed due to the wedge effect when lubricating oil is dragged between the protrusion 9a and the seal sliding surface 2b as the bearing rotates.
  • the peripheral speed of the relative rotation between the seal lip 9 and the seal sliding surface 2b (the direction of the arrow A in FIG. 3 is assumed) reaches a predetermined value, each projection 9a and the seal sliding surface 2b form an oil film.
  • the seal lip 9 and the seal sliding surface 2b are completely separated to form a fluid lubricating state, and this fluid lubricating state continues even at a higher peripheral speed. For this reason, the seal torque in the ball bearing 1 is reduced to the same level as when a non-contact seal is employed at a predetermined circumferential speed or higher, for example, 0.2 m/s or higher.
  • the protrusions 9a may be arranged at uniform intervals over the entire circumferential direction.
  • a groove extending in the circumferential direction may be formed in at least one portion of the protrusion 9a.
  • the projecting portion 9a may be shaped to form a wedge-shaped gap with the seal sliding surface 2b, which becomes smaller on the projecting portion 9a side.
  • the protrusion 9a may extend in a direction perpendicular to the circumferential direction, and may have an R shape that gradually approaches the seal sliding surface 2b toward the center of the width of the protrusion 9a in the circumferential direction.
  • the height and pitch of the protrusions 9a may be set so as to have the effect of preventing the entry of foreign matter having a particle size exceeding 0.05 mm, which may cause early damage to the ball bearing 1.
  • the height of the protrusions 9a may be set to zero. It may be set to 0.05 mm or more, or may be set to 0.05 mm or less.
  • the lubricating oil supplied to the inside of the bearing 7 has a kinematic viscosity of 7.0 mm 2 /s or less at 100°C.
  • the amount of grease G enclosed is set to 5 to 20% by volume of the total space volume of the bearing.
  • the total space volume of the bearing means that the bearing interior 7 (sealed space) surrounded by the cap members 6 provided at both axial ends of the inner and outer bearing rings 2 and 3, respectively, includes the balls 4 and the cage 5. is the space volume in which the ball bearing 1 is stopped.
  • the ball bearing 1 is as described above, and the bearing torque can be reduced by making the balls 4 made of nitride ceramics (Si 3 N 4 ). That is, the density of nitride ceramics (Si 3 N 4 ) is 3.304 g/cm 3 while the density of bearing steel (SUJ2) is 7.8 g/cm 3 .
  • the longitudinal elastic modulus of the nitride ceramics is 315 GPa, while the longitudinal elastic modulus of the bearing steel is 210 GPa.
  • the Poisson's ratio of the nitride ceramics is 0.25, while the Poisson's ratio of the bearing steel is 0.3.
  • the thermal expansion coefficient of the nitride ceramics is 3.2 ( ⁇ 10 ⁇ 6 /° C.), while the thermal expansion coefficient of the bearing steel is 12.5 ( ⁇ 10 ⁇ 6 /° C.). is.
  • the thermal conductivity of the nitride ceramics is 0.07 Cal/cm ⁇ s ⁇ °C, while the thermal conductivity of the bearing steel is 0.1 to 0.12 Cal/cm ⁇ s ⁇ °C. is.
  • ceramic balls generally have a larger longitudinal elastic modulus and higher rigidity than steel balls. Elastic hysteresis and differential slip are reduced, resulting in reduced bearing torque.
  • the ceramic ball 4 shown in FIG. 1 does not conduct electricity as compared to the steel ball. Therefore, electrolytic corrosion of the ball bearing 1 can also be prevented.
  • the ceramic balls 4 and the steel bearing rings 2 and 3 are made of different materials, so they do not weld. Therefore, the seizure resistance in the elastic contact area between the ball 4 and the bearing rings 2, 3 is superior to steel balls.
  • the ceramic ball 4 has higher rigidity than the steel ball.
  • the cap member 6 by providing the cap member 6, the amount of lubricating oil flowing into the bearing interior 7 is reduced, the stirring resistance is also reduced, and damage to the bearing due to foreign matter can be prevented and the bearing torque can be reduced.
  • the bearing torque was clearly smaller in the ball bearing provided with the non-contact seal as the cap member than in the open bearing. This result is considered to be because the amount of lubricating oil flowing into the bearing is suppressed by the cap member, and torque loss due to agitation of the lubricating oil inside the bearing works advantageously.
  • the cap member 6 of the ball bearing 1 shown in FIG. 1 exhibits low torque performance comparable to that of non-contact type seals and shields, so it prevents the entry of foreign matter with a predetermined particle diameter that causes early damage. , it is suitable for suppressing the inflow of lubricating oil.
  • Table 1 summarizes the advantages and disadvantages of open bearings with steel balls, bearings with contact seals with steel balls, and ball bearing 1 shown in FIG.
  • a lubricating oil having a kinematic viscosity of 7.0 mm 2 /s or less at 100° C. is suitable for suppressing the shear resistance of the lubricating oil and reducing the bearing torque.
  • the shear resistance is approximately determined by the following formula 1.
  • Formula 1: F ⁇ ⁇ (u / h) ⁇ s
  • F shear resistance
  • ⁇ oil viscosity coefficient
  • u fluid velocity
  • h oil film thickness
  • s sliding area.
  • the cross-sectional shape of the inner and outer raceway grooves 2a, 3a is circular with a diameter not more than 1.1 times the diameter of the ball 4, the elastic contact area between the ball 4 and the bearing rings 2, 3 It is possible to reduce the bearing torque while suppressing the surface pressure of the bearing.
  • the bearing torque was calculated with various groove diameters of the inner and outer raceway grooves.
  • the calculation result is shown in FIG. This calculation was performed for the model number of the ball bearing: 6006.
  • the calculation conditions were bearing rotation speed: 5000 min ⁇ 1 , radial load Fr: 730 N, axial load Fa: 0 N, lubricating oil: ISO viscosity VG10 (JIS K2001:1993).
  • the diameter of the ball is constant.
  • the load applied to the bearings in vehicle transmissions is about 35% of the dynamic load rating for both radial load and axial load.
  • the groove diameter of the inner and outer raceway grooves exceeds 1.1 times the ball diameter, the surface pressure in the elastic contact area will exceed 4200 MPa, which is the standard for static load rating.
  • the radial load is about 50% of the rated dynamic load, and the axial load is about 30%.
  • the groove diameter of the inner and outer raceway grooves exceeds 1.08 times the ball diameter, the surface pressure in the elastic contact area will exceed 4200 MPa, which is the standard for static load rating.
  • the ball bearing 1 shown in FIGS. 1 to 3 supports the rotation shafts S 20 , S 31 , S 32 included in the vehicle drive motor 20 or the transmission 30 connected to the vehicle drive motor 20.
  • the balls 4 made of a material different from steel, which is the material of the inner and outer bearing rings 2, 3
  • oil film breakage occurs in the elastic contact area between the balls 4 and the bearing rings 2, 3 during high-speed operation. Even if seizure occurs, the ball 4 and bearing rings 2 and 3, which are made of different materials, will not be welded together, improving seizure resistance.
  • the ball bearing 1 is set to have a bearing internal clearance larger than 0 ⁇ m during operation at 80° C. or higher, early damage due to negative operating clearance during high-speed rotation can be avoided.
  • the ball bearing 1 can prevent damage to the balls 4 and the bearing rings 2 and 3 even if a low-viscosity lubricating oil is used or the lubricating oil is diluted.
  • the ball bearing 1 is supplied with a low-viscosity lubricating oil having a kinematic viscosity of 7.0 mm 2 /s or less at 100° C. under the condition that the inflow of the lubricating oil is suppressed by the cap member 6.
  • the bearing torque can be reduced by satisfactorily reducing the resistance. In this way, the ball bearing 1 that supports the rotating shaft S 20 of the vehicle driving motor 20 and the like can both improve the low torque property and prevent damage.
  • the balls 4 since the balls 4 are made of ceramics, the balls 4 become insulators, and electrolytic corrosion does not occur in the elastic contact areas between the balls 4 and the bearing rings 2 and 3. Furthermore, when the ball 4 made of ceramics is used, the loss (elastic hysteresis, differential slip) in the elastic contact area between the ball 4 and the bearing rings 2, 3 is reduced compared to when the ball made of steel is used. Also from this, the ball bearing 1 can reduce the bearing torque.
  • the cross-sectional shape of the raceway grooves 2a, 3a of the inner and outer bearing rings 2, 3, respectively, is arcuate with a diameter not greater than 1.1 times the diameter of the ball 4. It is possible to reduce the bearing torque while suppressing the surface pressure in the elastic contact areas between the balls 4 and the bearing rings 2 and 3 to avoid adverse effects on the life of the bearing.
  • the ball bearing 1 is provided with the cap member 6 that realizes fluid lubrication of the seal lip 9 with respect to the seal sliding surface 2b. While the inflow is suppressed by the cap member 6, high-speed operation and low seal torque comparable to those of the non-contact seal can be realized.
  • the ball bearing 1 is filled with grease G as an initial lubricant in the bearing interior 7, and the amount of the grease G filled is 5 to 20% by volume of the total space volume of the bearing. It is possible to suppress the stirring resistance of the grease G while suppressing insufficient lubrication of the grease G.
  • At least one of nitrile rubber, acrylic rubber, fluororubber, cold-rolled steel plate, and stainless steel plate is used as the material of the cap member 6, so that the ball bearing 1 is generally used as a material for seals and shields.
  • the cap member 6 can be manufactured from a material suitable for the purpose.
  • the ball 4 is made of nitride-based ceramics, the ball 4 has comprehensively excellent mechanical properties such as light weight, high strength, and high toughness, so it is suitable for high-speed rotation.
  • the retainer 5 is a corrugated retainer, but the retainer may be of another type.
  • FIG. 7 shows a ball bearing 40 according to the second embodiment. It should be noted that only the points of difference from the first embodiment will be described here.
  • the inner and outer bearing rings 41 and the inner and outer bearing rings 42 of the ball bearing 40 are shielded.
  • the retainer 43 is a crown-shaped retainer made of synthetic resin.
  • the synthetic resin consists of fiber-reinforced polyamide resin or fiber-reinforced polyphenylene sulfide resin.
  • a shield groove 41a is formed in one bearing ring 41, and a cap member 44 is attached thereto.
  • a full circumference groove 42 a is formed in the other inner and outer races 42 to form a labyrinth clearance with the cap member 44 .
  • the cap member 44 is a non-contact shield made of cold-rolled steel plate or stainless steel plate.
  • Lubricating oil is splashed onto the ball bearing 40 from the right side of the drawing. This inflow of lubricating oil can be effectively suppressed only by providing a cap member 44 on the right side of the ball bearing 40 in the drawing.
  • the ball bearing 40 is provided with a crown-shaped retainer 43 made of synthetic resin, the retainer 43 is lighter and more self-lubricating than a corrugated retainer made of steel plate, which is suitable for reducing bearing torque. is.
  • the retainer 43 Since the synthetic resin of the ball bearing 40 is fiber-reinforced polyamide resin or fiber-reinforced polyphenylene sulfide resin, the retainer 43 has excellent deformation resistance against centrifugal force and is suitable for high-speed rotation.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Rolling Contact Bearings (AREA)
  • Sealing With Elastic Sealing Lips (AREA)
  • Sealing Of Bearings (AREA)
PCT/JP2022/028375 2021-07-27 2022-07-21 玉軸受 WO2023008313A1 (ja)

Priority Applications (2)

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CN202280052208.0A CN117751250A (zh) 2021-07-27 2022-07-21 球轴承
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Applications Claiming Priority (2)

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JP2021122252A JP2023018262A (ja) 2021-07-27 2021-07-27 玉軸受
JP2021-122252 2021-07-27

Publications (1)

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WO2023008313A1 true WO2023008313A1 (ja) 2023-02-02

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KR (1) KR20240038746A (ko)
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Cited By (1)

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CN116379062A (zh) * 2023-04-07 2023-07-04 临高化的接科技有限公司 一种具有双向推力的球轴承

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JP2001335369A (ja) * 2000-05-23 2001-12-04 Toshiba Corp 窒化ケイ素セラミックス焼結体およびそれを用いた耐摩耗性部材
JP2012219850A (ja) * 2011-04-05 2012-11-12 Ntn Corp 車両用モータ駆動装置および自動車
JP2013015180A (ja) * 2011-07-04 2013-01-24 Nsk Ltd 単列深溝型ラジアル玉軸受
JP2013160314A (ja) * 2012-02-06 2013-08-19 Nsk Ltd 転がり軸受
JP2014084913A (ja) * 2012-10-22 2014-05-12 Nsk Ltd 転がり軸受
JP2017161082A (ja) * 2017-06-15 2017-09-14 Ntn株式会社 デファレンシャル用またはトランスミッション用深溝玉軸受
JP2019074196A (ja) * 2017-10-19 2019-05-16 Ntn株式会社 シール付玉軸受

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JP2016143786A (ja) 2015-02-03 2016-08-08 株式会社東芝 半導体装置

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Publication number Priority date Publication date Assignee Title
JP2001335369A (ja) * 2000-05-23 2001-12-04 Toshiba Corp 窒化ケイ素セラミックス焼結体およびそれを用いた耐摩耗性部材
JP2012219850A (ja) * 2011-04-05 2012-11-12 Ntn Corp 車両用モータ駆動装置および自動車
JP2013015180A (ja) * 2011-07-04 2013-01-24 Nsk Ltd 単列深溝型ラジアル玉軸受
JP2013160314A (ja) * 2012-02-06 2013-08-19 Nsk Ltd 転がり軸受
JP2014084913A (ja) * 2012-10-22 2014-05-12 Nsk Ltd 転がり軸受
JP2017161082A (ja) * 2017-06-15 2017-09-14 Ntn株式会社 デファレンシャル用またはトランスミッション用深溝玉軸受
JP2019074196A (ja) * 2017-10-19 2019-05-16 Ntn株式会社 シール付玉軸受

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116379062A (zh) * 2023-04-07 2023-07-04 临高化的接科技有限公司 一种具有双向推力的球轴承
CN116379062B (zh) * 2023-04-07 2024-06-04 南京金崎新能源动力研究院有限公司 一种球轴承

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KR20240038746A (ko) 2024-03-25
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