(19)
(11)EP 3 475 591 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
14.04.2021 Bulletin 2021/15

(21)Application number: 17734586.5

(22)Date of filing:  18.06.2017
(51)International Patent Classification (IPC): 
F16C 33/38(2006.01)
F16C 33/44(2006.01)
F16C 33/66(2006.01)
F16C 19/10(2006.01)
(86)International application number:
PCT/US2017/038058
(87)International publication number:
WO 2018/005138 (04.01.2018 Gazette  2018/01)

(54)

SYNTHETIC RESIN RETAINER FOR LARGE THRUST BALL BEARINGS WITH DRY-LUBRICANT AND WET-LUBRICANT MANAGEMENT SYSTEMS

SYNTHETISCHEN HARZKÄFIG FÜR GROSSE AXIALLAGER MIT TROCKEN SCHMIERUNG UND FLÜSSIGSCHMIERUNG LEITSYSTEM

CAGE EN RÉSINE SYNTHÉTIQUE POUR GRANDE BUTÉE À ROULEMENT AVEC LUFRIFIANT SEC ET SYSTÈME DE GESTION DE LUBRIFIANT LIQUIDE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 26.06.2016 US 201615193077

(43)Date of publication of application:
01.05.2019 Bulletin 2019/18

(73)Proprietor: ATEC Corporation
Cypress, CA 90630 (US)

(72)Inventor:
  • TRAN, Anh
    DECEASED (US)

(74)Representative: Ricker, Mathias 
Wallinger Ricker Schlotter Tostmann Patent- und Rechtsanwälte Partnerschaft mbB Zweibrückenstrasse 5-7
80331 München
80331 München (DE)


(56)References cited: : 
EP-A1- 1 847 727
DE-U- 1 866 122
JP-A- 2003 013 963
DE-A1- 3 512 202
JP-A- 2002 295 478
JP-A- 2007 092 957
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    CROSS-REFERENCE TO RELATED APPLICATION


    1. Field of the Invention



    [0001] This invention is related to ball bearings in general and, more particularly, to ball bearing retainers (also known as separators or cages) and a lubrication management system for large thrust ball bearings and to an integrated angular contact thrust bearing system.

    2. Description of Related Art and Other Considerations



    [0002] A conventional ball bearing assembly typically contains four basic components comprising an outer or top ring, an inner or bottom ring, a ball retainer (separators or cages) sandwiched between the two rings, rolling elements or ball bearings held by the ball retainer and a lubricant. The ball retainer and its contained rolling elements bearings form a ball bearing-retainer or bearing assembly. The bearing assembly has its rolling elements circumferentially spaced apart from one another and between the two rings. Thus, the retainer maintains the circumferential spacing between adjacent roller elements. The retainer is typically a single piece part having cylindrical holes or pockets to hold the ball bearings.

    [0003] A conventional thrust ball bearing retainer is formed as a solid single-piece component and ordinarily provides a satisfactory means for retaining spacing rolling elements around the bearing raceways for small and medium sized bearings, such as having a pitch diameter which is less than 6". However, for large or larger thrust ball bearings, such large thrust ball bearings become very expensive to make or even become un-producible resulting from such distortions as excessive out-of-round, out-of-flatness, and torsional wrap. In addition, for applications requiring extreme operating temperatures, such solid, single-piece retainers become a limiting factor due to thermal induced binding resulting from a coefficient of thermal expansion mismatch between the retainer and raceway materials. In addition, conventional thrust ball bearing retainers are designed for use with liquid lubricants and may not work at all when liquid lubricants are not applicable or otherwise not to be used. This results in limiting their use in applications where liquid lubricants are not applicable, such as where the ambient cold operating temperature is less than the pour point temperature of any liquid lubricant or where the ambient hot operating temperature exceeds the flash point temperature of any liquid lubricant or where the running torque excursions due to temperature levels do not meet a particular system capability or performance.
    The EP 1847 727 A1 discloses a thin wall bearing, comprising a retainer formed in a divided type having a plurality of resin platelike members, curved along an inner ring and an outer ring and wherein the members adjoin each other at essentially right angels. The retainer comprises pockets opening to the axial end part thereof and rollingly holding balls. Slit like through holes extending in the axial direction and opening to the axial end part where the opening parts of the pockets are positioned are formed at the center parts of pillars between the pockets and adjacent to each other. The parts As a result, the thin wall bearing can have excellent lubricity.

    [0004] The DE 35 12 202 A1 discloses a cross roller bearing having a plurality of circular pockets, wherein the retainer is split into a plurality of segments to significantly reduce compressive loads acting on the cage.

    SUMMARY OF THE INVENTION



    [0005] In the present invention, the thrust ball bearing comprises an outer or top and inner or bottom rings, a plurality of rolling elements, which are mounted between the rings, and a retainer for retaining circumferentially spaced rolling elements apart from one another. The different configuration includes the following improvements.

    [0006] The retainer is segmented into multiple circular arc pieces in which each piece holds a given number of balls. The number of retainer segments is selected accordingly in order to reduce thermal induced effects on torque, sliding friction torque and dynamics induced effects between the retainer segments and other bearing components (i.e., ball, bearing rings, etc.).

    [0007] The retainer ends of the segments are rounded to minimize the radially transferring forces and the retainer wear between two adjacent segments.

    [0008] The retainer segments are designed to have a guided feature on the inner or bottom raceway shoulders. This double inner or bottom raceway shoulder guided feature minimizes the retainer dynamic instability and the pocket wear due to a much lower retainer/inner raceway relative velocity as compared with the conventional ball guided retainer or double outer and inner raceway shoulder guided retainer. In addition, this feature also avoids excessive solid lubricant transferred from retainer pockets to balls and subsequently to raceway track/ball interfaces. Thus, excessive high torque noise is avoided due to deposited solid lubricant on raceway/ball interfaces. The single raceway shoulder guided feature from the retainer also prevent brake action when the retainer segments contact the shoulders of both lower upper raceways.

    [0009] The retainer pocket is circular and the pocket/ball clearance is selected to account for the part tolerance and the thermal induced dimensional change in order to prevent the ball/retainer interference.

    [0010] In the case of excessive thermal induced dimensional change due to a combination of excessive mismatch between the coefficients of thermal expansion between raceway and retainer materials and extreme operating temperature, the retainer ball pocket is selected to have an oval cross section with the major axis along the circumferential direction.

    [0011] For an application where the environmental conditions exclude the use of liquid lubricants, a solid lubricant mechanism is applied as follows: (a) the bearing ring internal surfaces are modified for optimal friction and wear by an electroplating process. The anodizing thickness is selected to prevent case crushing under Hertzian contact stress between the ball and the raceway; (b) electroplated surfaces are covered with a molecular layer of per-fluorinated polyether based fluid; (c) a lubrication resupply mechanism is derived from the use of a double transfer film applied from the bearing retainer pockets to the balls and from the balls to the raceway tracks. Retainer materials are selected as a lubricant resupply reservoir and provides the needed lubricant to all bearing component interfaces through kinematic contacts; (d) the proper amount of lubricant resupply is controlled by retainer material, interface clearances, environmental operating conditions and bearing kinematic relationship between the bearing components.

    [0012] For an application which the environmental conditions including the use of liquid lubricants, a liquid lubricant mechanism is applied as follows: (a) to provide the initial wear protection, bearing ring internal surfaces are modified for optimal friction and wear by electroplating process; (b) synthetic hydrocarbon base oils provide good lubricity and low wear in a slow-to-moderate speed application as this thrust ball bearings. Greases or oils can be used. The proper choice of these forms of lubricants depends on allowable resistance bearing torque, operating temperature, speed, and torque noise; (c) retainer material is a molded, synthetic resin with added fillers to increase strength and to reduce wear rate, (d) the proper amount of lubricant resupply is controlled by retainer material, interface clearances, environmental operating conditions and bearing kinematic relationship between the bearing components.

    [0013] To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings. The invention is defined in the appended claims.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0014] In the annexed drawings, like references indicate like parts or features.

    FIG. 1 is an isometric view of a conventional or prior art thrust ball bearing assembly.

    FIG. 1A is a cross-section taken along line 1A-1A of FIG. 1.

    FIG. 2 is an isometric view of the conventional, single-piece, thrust ball bearing retainer and its contained ball bearings as shown in the FIG. 1 assembly.

    FIG. 3 is an isometric view of a section of the conventional thrust ball bearing retainer with cylindrical pockets of the thrust ball bearing assembly as illustrated in FIGS. 1 and 2.

    FIG. 4 is an isometric exploded view of a preferred embodiment of the present invention comprising a thrust ball bearing assembly in which its ball bearing retainer has individual thrust ball bearing pockets with wedges for supporting the several ball bearings.

    FIG. 5 is an exploded view of the embodiment shown in FIG. 4 taken along cross-section line 5-5 thereof.

    FIG. 6 is a cross-sectional view of the assembled embodiment illustrated in FIGS. 4 and 5 depicting its wedge-shaped thrust ball bearing pocket in the retainer.

    FIG. 7 is an enlarged cross-sectional view of a portion of the thrust ball bearing retainer taken along the circular line denoted "7" in FIG. 6 to better shown the wedge-shaped thrust ball bearing pocket in the retainer.

    FIG. 8 is a further enlarged cross-sectional view of a single thrust ball bearing retainer pocket with a ball bearing supported therein to best show the wedge-shaped thrust ball bearing support in the retainer.

    FIG. 9 is a top view of a first embodiment of a segment of the retainer employable in the thrust ball bearing assembly as shown in FIG. 4 in which the thrust ball bearing retainer has circular pockets for the ball bearings..

    FIG. 9A is a view of the retainer circular pocket of FIG. 9.

    FIG. 10 is an isometric view of a second embodiment of a segment of the retainer employable in the thrust ball bearing assembly as shown in FIG. 4 in which the thrust ball bearing retainer has alternatively slotted ball pockets.

    FIG. 11 is an isometric view of a third embodiment of a segment of the retainer employable in the thrust ball bearing assembly as shown in FIG. 4 in which the thrust ball bearing retainer has oval pockets for the ball bearings.

    FIG. 11A is a view of the retainer oval pocket of FIG. 11.

    FIG. 12 is a cross-section taken along lines 12-12 of FIGS. 9-11 depicting the rounded ends having radii R1 and R2 terminating their respective retainer segments.


    DETAILED DESCRIPTION OF THE INVENTION



    [0015] A conventional ball bearing assembly typically contains four basic components as depicted in FIGS. 1-3. Such a prior art assembly, denoted by indicium 20, comprises an outer or top ring 22, an inner or bottom ring 24, a ball retainer 26 (sometimes termed separator or cage) sandwiched between rings 22 and 24, rolling elements or ball bearings 28 held by the ball retainer. A lubricant (not shown) is often included. Ball retainer 26 and its contained rolling elements bearings 28 form an assembly 30 as best seen in FIG. 2. Each ring 22 and 24 include a race 32 as best shown in FIG. 1A for ball-bearings 28.

    [0016] Bearing assembly 30 has its rolling elements 28 circumferentially spaced apart from one another and between outer or top ring 22 and inner or bottom ring 24. Thus, retainer 26 maintains the circumferential spacing between adjacent roller elements 28. The retainer is typically a single piece part with cylindrical holes or pockets 34.

    [0017] A conventional thrust ball bearing retainer, such as retainer 26, which is formed as a solid, single-piece component, ordinarily provides a satisfactory means for retaining spacing rolling elements 28 around the bearing raceways for small and medium sized bearings, such as those having a pitch diameter which is less than 6". However, for large or larger thrust ball bearings, such a large thrust ball bearing becomes very expensive to manufacture or even becomes un-producible due to excessive out-of-round, out-of-flatness, and torsional wrap. In addition, for applications requiring extreme operating temperatures, such solid, single-piece retainers become a limiting factor due to thermally induced binding resulting from a coefficient of thermal expansion mismatch between their retainer and raceway materials. In addition, conventional thrust ball bearing retainers are designed for use with liquid lubricants and may not work at all when liquid lubricants are not applicable or otherwise not to be used. Such a lack of a lubricant results in limiting its use in applications where liquid lubricants are not applicable, such as where the ambient cold operating temperature is less than the pour point temperature of any liquid lubricant or where the ambient hot operating temperature exceeds the flash point temperature of any liquid lubricant or such as where the running torque excursions due to temperature levels do not meet a particular system capability or performance.

    [0018] Reference is now made to FIGS. 4-12 and to the embodiments of the present invention. As depicted in FIGS. 4-8, a thrust ball bearing assembly 40 comprises an outer or top ring 42, an inner or bottom ring 44, a retainer 46, and a plurality of rolling elements or ball bearings 48 retained within and spaced apart from one another by the retainer. Elements 48 are thereby mounted between outer or top ring 42 and inner or bottom ring 44. The combination of the ball bearings and the retainer forms a bearing-retainer assembly 50. Retainer 46 is generalized in FIGS. 4 and 5 as a representation which is configured into specific formulations as depicted in subsequent figures.

    [0019] Rings 42 and 44 each are provided with bearing ring internal races or raceways 52 bounded by raceway shoulders 54a and 54b. Ball bearings 48 are disposed to be seated within the raceways and to roll therewithin. As best shown in FIG. 8, retainer 46 includes pockets 56 having openings 58 for reception of individual ball bearings. Each opening 58 has rounded parallel sides (e.g., circularly or ovally shaped as depicted and described hereinafter) to enable its ball bearing to be inserted into its pocket 56 and each parallel sided opening 58 terminates in a rounded wedge-shaped seat 60. As also illustrated in FIGS. 6 and 7, the retainer is bounded with upper and lower surfaces 62a and 62b. Upper surface 62a is spaced from raceway shoulder 54a of top ring 42. Lower surface 62b is disposed to rest upon raceway shoulder 54b of lower ring 44.

    [0020] In accordance with one feature of the present invention, the retainer is segmented into multiple circular arc pieces or segments 146, 246 and 346, as illustrated respectively in FIGS. 9, 10, and 11. Each piece is designed to hold a certain number of balls. The number of retainer segments is selected in consonance with those needs such as will reduce thermal induced effects on torque, sliding friction torque and dynamics induced effects between the retainer segments and other bearing components including, but not limited to, such components as balls and bearing rings. As illustrated in FIGS. 9-11, segments 146, 246 and 346 respectively include pockets 156, 256 and 356, openings 158, 258 and 358, wedge-shaped seats 160, 260 and 360. FIGS. 9 and 9A illustrate pockets with a circular cross-section. Pockets 258 in FIG. 10, in addition to pockets also having a circular cross-section, are slotted with slots 262. Pockets 356 in FIGS. 11 and 11A have an oval configuration; such a modification is described below.

    [0021] In accordance with another feature of the present invention, segments 154, 254 and 354 are each terminated with similar rounded retainer ends 64 (see FIG. 12) each having two radii 64a and 64b with respective radii dimensions, R1 and R2, to minimize radially transferring forces and retainer wear between adjacent segments.

    [0022] In accordance with another feature of the present invention, the several retainer segments are designed to have the guided feature on the inner or bottom raceway shoulders 54b. This double inner or bottom raceway shoulder 54b guided feature minimizes the retainer dynamic instability and the pocket wear due to much lower retainer/inner raceway relative velocity as compared to the conventional ball guided retainer. In addition, this feature also avoids excessive solid lubricant transferred from retainer pockets to ball bearings and subsequently to raceway track/ball interfaces, thereby avoiding the deposit of excessive solid lubricant on raceway/ball interfaces that otherwise cause high torque noise. The single raceway shoulder guided feature from the retainer also prevent brake action when the retainer segments contact both shoulders on the lower and upper raceways.

    [0023] In accordance with still another aspect of the present invention, the retainer pocket is rounded (circular or otherwise) and the pocket/ball clearance is selected to account for the part tolerance and the thermal induced dimensional change in order to prevent the ball/retainer interference.

    [0024] In accordance with another feature of the present invention, in the case of excessive thermal induced dimensional change due to a combination of excessive mismatch between the coefficients of thermal expansion between raceway and retainer materials and extreme operating temperature, the retainer ball pocket is selected to have an oval cross section with the major axis along the circumferential direction. The semi-major axis dimension, a, is calculated according to the below formula:

    where

    b = dballratio, mm

    dball = ball diameter, mm

    ratio = 1.025-1.10, mm

    d = bearing pitch diameter, mm

    nsegment = number of retainer segments per bearing row

    Thot = extreme operating hot temperature, °C

    Tcold = extreme operating cold temperature, °C

    αretainer = thermal coefficient of expansion for ball retainer material along the circumferential direction, 1/°C

    αraceway = thermal coefficient of expansion for raceway material,1/°C

    tol = pocket diametral manufacturing tolerance, mm



    [0025] In accordance with another feature of the present invention, for an application which the environmental conditions excluding the use of liquid lubricants, a solid lubricant mechanism is applied as follows:
    1. 1. To provide the initial wear protection, bearing ring internal surfaces 52 are modified for optimal friction and wear by an electroplating process. For example, if bearing rings are made of structural aluminum such as 6061-T6 or 7075-T6, a hard anodizing coating, type 3, with polytetrafluoroethylene (PTFE) sealing is applied. The anodizing thickness is selected to prevent case crushing under Hertzian contact stress between the ball and the raceway.
    2. 2. In addition, electroplating surfaces 52 are covered with a molecular layer of per-fluorinated polyether based fluid such as Castrol Brayco 815z.
    3. 3. Lubrication resupply mechanism comes from the double transfer film from bearing retainer pockets to balls and from balls to raceway tracks. Retainer materials are selected as a lubricant resupply reservoir and to provide the needed lubricant to all bearing component interfaces through kinematic contacts. For example, a retainer material can be molded, synthetic resin, self-lubricated material reinforced with carbon fiber, molybdenum disulfide, and polytetrafluoroethylene (PTFE).
    4. 4. The proper amount of lubricant resupply is controlled by retainer material, interface clearances, environmental operating conditions and bearing kinematic relationship between the bearing components.


    [0026] In accordance with another feature of the present invention, for an application which the environmental conditions including the use of liquid lubricants, a liquid lubricant mechanism is applied as follows:
    1. 1. To provide the initial wear protection, bearing ring internal surfaces 52 are modified for optimal friction and wear by anelectroplating process. For example, if bearing rings 42 and 44 are made of structural aluminum such as 6061-T6 or 7075-T6, a hard anodizing coating, type 3, with an organic polymer, such as polytetrafluoroethylene (PTFE), sealing is applied.
    2. 2. In addition, synthetic hydrocarbon base oils such as polyalphaolephines (PAO) or multiply-alkylated cyclopentanes (MACs Multiply-Alkylated Cyclopentanes) with wear protection additives such as lead napthenate or tricresyl phosphate show good lubricity and low wear in a slow-to-moderate speed application as this thrust ball bearings. Greases or oils can be used. The proper choice of these forms of lubricants depends on allowable resistance bearing torque, operating temperature, speed, and torque noise.
    3. 3. Retainer material is a molded, synthetic resin such as polyamide (PA) or polyetherether ketone (PEEK) or polyamide-imide PAI with added fillers such as glass fiber or carbon fiber to increase strength and to reduce wear rate.
    4. 4. The proper amount of lubricant resupply is controlled by retainer material, interface clearances, environmental operating conditions and bearing kinematic relationship between the bearing components.


    [0027] To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.

    [0028] More specifically, for a large solid, single-piece retainer, the tolerance on out-of-round and out-of-flatness is extremely tight in order to avoid the retainer locking due to ball/retainer interactions.

    [0029] Although the invention has been shown and described with respect to a certain embodiment or embodiments, equivalent alterations and modifications may occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a "means") used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.


    Claims

    1. A ball bearing assembly (40) comprising (a) top (42) and bottom (44) rings having ball bearing raceways (52) facing one another and (b) a ball bearing retainer (46) which supports a plurality of ball bearings (48), which is sandwiched between said top (42) and bottom (44) rings and which enables said ball bearings (48) to reside within said raceways (52), the improvement in which said retainer (46) comprises a plurality of arced segments (146; 246; 346) which together form a circle, wherein
    said retainer (46) is provided with pockets (156; 256; 356) for said ball bearings (48) and
    said retainer ball pockets (156; 256; 356) are selected to have an oval cross-section with its major axis along its circumferential direction in which its semi-major axis dimension, a, is calculated according to the below formula:

    where

    b = dballratio, mm

    dball = ball diameter, mm

    ratio = 1.025 - 1.10, mm

    d = bearing pitch diameter, mm

    nsegment = number of retainer segments per bearing row

    Thot = extreme operating hot temperature, °C

    Tcold = extreme operating cold temperature, °C

    αretainer = thermal coefficient of expansion for ball retainer material along the circumferential direction, 1/°C

    αraceway = thermal coefficient of expansion for raceway material, 1/°C

    tol = pocket diametral manufacturing tolerance, mm.


     
    2. The ball bearing assembly (40) according to claim 1 wherein each of said retainer segments (146; 246; 346) have ends (64) respectively contacting adjacent ones of said segments and wherein each of said segment ends (64) are rounded so as to minimize any radially transferring forces and any retainer wear between adjacent ones of said segments.
     
    3. The ball bearing assembly (40) according to claim 2 in which the rounding of said ends (64) are each provided with two radii (64a, 64b) terminating their respective retainer segments (146; 246; 346) for minimizing and radially transferring forces and any such retainer wear between said adjacent ones of said segments.
     
    4. The ball bearing assembly (40) according to claim 1 in which the number of said retainer arced segments (146; 246; 346) is accordingly selected to reduce any thermal induced effects on torque, sliding friction torque and dynamics induced effects amongst said retainer segments, said rings and said ball bearings.
     
    5. The ball bearing assembly (40) according to claim 4 wherein each of said retainer segments (146; 246; 346) have ends (64) respectively contacting adjacent ones of said segments and wherein each of said segment ends are rounded so as to minimize any radially transferring forces and any retainer wear between adjacent ones of said segments.
     
    6. The ball bearing assembly according to claim 5 in which the rounding of said ends (64) are each provided with two radii (64a, 64b) terminating their respective retainer segments (146; 246; 346) for minimizing and radially transferring forces and any such retainer wear between said adjacent ones of said segments.
     
    7. The ball bearing assembly (40) according to claim 1 wherein:

    said top (42) and bottom (44) rings each include shoulders (54a; 54b) surrounding said raceways (52);

    each of said segments (146; 246; 346) include pockets (156; 256; 356) for retaining said ball bearings (48); and said pockets (156; 256; 356) have wedges (60; 160; 260; 360) on which said ball bearings (48) reside whereby said

    pocket wedges (60; 160; 260; 360) prevent said retainer segments (146; 246; 346) from simultaneously contacting said bottom ring raceway shoulders (54b) and top raceway shoulders (54a).


     
    8. The ball bearing assembly (40) according to claim 7 wherein:

    said ball bearings (48) and said retainer pockets (156; 256; 356) have interfaces therebetween; and

    said retainer pockets (156; 256; 356) have slots (262) therein for increasing compliance between said ball/pocket interfaces for helping to reduce any dynamic induced effects between said ball bearings and said pockets.


     
    9. The ball bearing assembly (40) according to claim 1 in which
    said retainer segments (146; 246; 346) are provided with pockets (156; 256; 356) to retain said ball bearings (48),
    said rings (42, 44) include raceways (52) for said ball bearings (48), solid lubricants are included in said pockets (156; 256; 356),
    said bearing ring raceways (52) have electroplated surfaces, and
    an organic polymer sealing material is applied to said pockets and to said raceways to optimize any friction and wear thereamongst.
     
    10. The ball bearing assembly (40) according to claim 9 in which said raceways (52) are covered with a molecular thin layer comprising a per-fluorinated polyether or said raceways are covered with a molecular thin layer of a per-fluorinated polyether.
     
    11. The ball bearing assembly (40) according to claim 9 in which:

    said ball bearings (48) and said retainer pockets (156; 256; 356) have bearing component interfaces therebetween; and

    said retainer (46) is formed from materials selected to act as a lubricant resupply reserveoir for providing any needed lubricant to all said bearing component interfaces through kinematic contact therebetween.


     
    12. The ball bearing assembly (40) according to claim 11 in which said retainer materials comprise one of a molded, synthetic resin, self-lubricated material reinforced with carbon fiber, molybdenum disulfide, and polytetrafluoroethylene (PTFE).
     
    13. The ball bearing assembly (40) according to claim 11 in which said lubricant resupply reservoir is made sufficient in amount as controlled by said retainer material acting as lubricant resupply reservoir, the interface clearances, existing environmental operating conditions and such bearing kinematic relationships as exist between said retainer segments, said rings and said ball bearings.
     
    14. The ball bearing assembly (40) according to claim 11 in which said bearing rings (42, 44) have internal surfaces which are modified for optimal friction and wear by being electroplated and enhanced with applied polytetrafluoroethylene (PTFE) sealing.
     
    15. The ball bearing assembly (40) according to claim 11 further including synthetic hydrocarbon base oils with wear protection additives for application in slow-to-moderate speed use with respect to said ball bearings.
     
    16. The ball bearing assembly (40) according to claim 15 in which said synthetic hydrocarbon base oils comprise polyalphaolephines (PAO) or multiply-alkylated cyclopentanes (MACs Multiply-Alkylated Cyclopentanes) and said wear protection additives comprise lead napthenate or tricresyl phosphate and further including greases and oils as necessary depending on allowable resistance bearing torque, operating temperature, speed and torque noise.
     
    17. The ball bearing assembly (40) according to claim 15 in which said retainer material comprises one of a molded, synthetic resin with added fillers for increased strength of said retainer and for reducing wear rate thereof.
     
    18. The ball bearing assembly (40) according to claim 1 wherein said retainer (46) as provided with pockets (156; 256; 356) for said ball bearings (48) is formed from materials selected to act as a lubricant resupply reservoir for providing any needed lubricant to all said bearing component interfaces and, in the case of excessive thermal induced dimensional change due to a combination of excessive mismatch between the coefficients of thermal expansion between said raceway (52) and said retainer materials and extreme operating temperature, said retainer ball pockets (156; 256; 356) are selected to have an oval cross-section.
     
    19. A ball bearing assembly (40) comprising (a) a top circular ring (42) and a bottom circular ring (44), each said ring having ball bearing raceways (52) which raceways face one another and (b) a ball bearing retainer which supports a plurality of ball bearings (48), which is sandwiched between said top ring and said bottom ring and which enables said ball bearings to reside within said raceways and in which said retainer comprises a plurality of arced segments (146; 246; 346) which together form a circle, and wherein each of said retainer segments (146; 246; 346) have ends (64) respectively contacting adjacent ones of said segments and wherein each of said segment ends (64) are rounded so as to minimize any radially transferring forces and any retainer wear between adjacent ones of said segments, and in which the rounding of said ends are each provided with two radii (64a, 64b) terminating their respective retainer segments for minimizing any such radially transferring forces and any such retainer wear between said adjacent ones of said segments.
     
    20. The ball bearing assembly (40) according to claim 19 wherein said retainer (46) is provided with pockets (156; 256; 356) for said ball bearings (48) and is formed from materials selected to act as a lubricant resupply reservoir for providing any needed lubricant to all said bearing component interfaces and, in the case of excessive thermal induced dimensional change due to a combination of excessive mismatch between the coefficients of thermal expansion between said raceway and said retainer materials and extreme operating temperature, said retainer ball pockets are selected to have an oval cross-section with its major axis along its circumferential direction in which its semi-major axis dimension, a, is calculated according to the below formula:

    where

    b = dballratio, mm

    dball = ball diameter, mm

    ratio = 1.025 - 1.10, mm

    d = bearing pitch diameter, mm

    nsegment = number of retainer segments per bearing row

    Thot = extreme operating hot temperature, °C

    Tcold = extreme operating cold temperature, °C

    αretainer = thermal coefficient of expansion for ball retainer material along the circumferential direction, 1/°C

    αraceway = thermal coefficient of expansion for raceway material, 1/°C

    tol = pocket diametral manufacturing tolerance, mm.


     


    Ansprüche

    1. Kugellageranordnung (40), aufweisend (a) obere (42) und untere (44) Ringe mit einander zugewandten Kugellagerlaufbahnen (52) und (b) einen Kugellagerkäfig (46), der eine Mehrzahl von Kugellagern (48) trägt, der zwischen dem oberen (42) und dem unteren (44) Ring angeordnet ist und der es den Kugellagern (48) ermöglicht, sich in den Laufbahnen (52) zu befinden, wobei die Verbesserung darin besteht, dass der Käfig (46) eine Mehrzahl von bogenförmigen Segmenten (146; 246; 346) aufweist, die zusammen einen Kreis bilden, wobei
    der Käfig (46) mit Taschen (156; 256; 356) für die Kugellager (48) versehen ist und die Käfigkugeltaschen (156; 256; 356) so gewählt sind, dass sie einen ovalen Querschnitt aufweisen, dessen Hauptachse entlang der Umfangsrichtung verläuft und dessen Halbhauptachsenabmessung, a, gemäß der folgenden Formel berechnet wird:

    wobei

    b = dKugel*Verhältnis, mm

    dKugel = Kugeldurchmesser, mm

    Verhältnis = 1,025 - 1,10, mm

    d = Durchmesser der Lagerteilung, mm

    nSegment = Anzahl der Käfigsegmente pro Lagerreihe

    Twarm = extreme Betriebs-Warmtemperatur, °C

    Tkalt = extreme Betriebstemperatur kalt, °C

    αKäfig = thermischer Ausdehnungskoeffizient für Kugelkäfigmaterial in Umfangsrichtung, 1/°C

    αLaufbahn = thermischer Ausdehnungskoeffizient für Laufbahnmaterial, 1/°C

    tol = Fertigungstoleranz für den Taschendurchmesser, mm.


     
    2. Kugellageranordnung (40) nach Anspruch 1, wobei jedes der Käfigsegmente (146; 246; 346) Enden (64) aufweist, die jeweils benachbarte der Segmente berühren, und wobei jedes der Segmentenden (64) abgerundet ist, um jegliche radial übertragenden Kräfte und jeglichen Käfigverschleiß zwischen benachbarten der Segmente zu minimieren.
     
    3. Kugellageranordnung (40) nach Anspruch 2, bei der die Abrundungen der Enden (64) jeweils mit zwei Radien (64a, 64b) versehen sind, die ihre jeweiligen Käfigsegmente (146; 246; 346) abschließen, um jegliche radial übertragenden Kräfte und jeglichen derartigen Käfigverschleiß zwischen den benachbarten der Segmente zu minimieren.
     
    4. Kugellageranordnung (40) nach Anspruch 1, bei der die Anzahl der Käfigbogensegmente (146; 246; 346) entsprechend gewählt ist, um jegliche thermisch induzierten Effekte auf das Drehmoment, das Gleitreibungsmoment und die dynamisch induzierten Effekte zwischen den Käfigbogensegmenten, den Ringen und den Kugellagern zu reduzieren.
     
    5. Kugellageranordnung (40) nach Anspruch 4, wobei jedes der Käfigsegmente (146; 246; 346) Enden (64) aufweist, die jeweils benachbarte der Segmente berühren, und wobei jedes der Segmentenden abgerundet ist, um jegliche radial übertragenden Kräfte und jeglichen Käfigverschleiß zwischen benachbarten der Segmente zu minimieren.
     
    6. Kugellageranordnung nach Anspruch 5, bei der die Abrundungen der Enden (64) jeweils mit zwei Radien (64a, 64b) versehen sind, die ihre jeweiligen Käfigsegmente (146; 246; 346) abschließen, um jegliche radial übertragenden Kräfte und jeglichen derartigen Käfigverschleiß zwischen den benachbarten der Segmente zu minimieren.
     
    7. Kugellageranordnung (40) nach Anspruch 1, wobei:

    die oberen (42) und unteren (44) Ringe jeweils Schultern (54a; 54b) aufweisen, die die Laufbahnen (52) umgeben;

    jedes der Segmente (146; 246; 346) Taschen (156; 256; 356) zur Aufnahme der Kugellager (48) aufweist; und die Taschen (156; 256; 356) Keile (60; 160; 260; 360) aufweisen, auf denen die Kugellager (48) sitzen, wodurch die Taschenkeile (60; 160; 260; 360) verhindern, dass die Käfigsegmente (146; 246; 346) gleichzeitig die unteren Ringlaufbahnschultern (54b) und die oberen Laufbahnschultern (54a) berühren.


     
    8. Kugellageranordnung (40) nach Anspruch 7, wobei:

    die Kugellager (48) und die Käfigtaschen (156; 256; 356) Grenzflächen dazwischen aufweisen; und

    die Käfigtaschen (156; 256; 356) Schlitze (262) darin aufweisen, um die Nachgiebigkeit zwischen den Kugel/Taschen-Grenzflächen zu erhöhen, um dazu beizutragen, jegliche dynamisch induzierten Effekte zwischen den Kugellagern und den Taschen zu reduzieren.


     
    9. Kugellageranordnung (40) nach Anspruch 1, bei der
    die Käfigsegmente (146; 246; 346) mit Taschen (156; 256; 356) versehen sind, um die Kugellager (48) zu halten,
    die Ringe (42, 44) Laufbahnen (52) für die Kugellager (48) aufweisen, Festschmierstoffe in den Taschen (156; 256; 356) enthalten sind,
    die Lagerring-Laufbahnen (52) galvanische Oberflächen aufweisen, und
    ein organisches Polymer-Dichtungsmaterial auf die Taschen und auf die Laufbahnen aufgebracht ist, um jegliche Reibung und Abnutzung dazwischen zu optimieren.
     
    10. Kugellageranordnung (40) nach Anspruch 9, bei der die Laufbahnen (52) mit einer molekularen Dünnschicht bedeckt sind, die einen perfluorierten Polyether aufweisen, oder die Laufbahnen mit einer molekularen Dünnschicht aus einem perfluorierten Polyether bedeckt sind.
     
    11. Kugellageranordnung (40) nach Anspruch 9, bei der:

    die Kugellager (48) und die Käfigtaschen (156; 256; 356) Lager-Komponentengrenzflächen dazwischen aufweisen; und

    der Käfig (46) aus Materialien gebildet ist, die so ausgewählt sind, dass sie als Schmiermittelvorratsbehälter zum Bereitstellen von benötigtem Schmiermittel für alle Lagerkomponentenschnittstellen durch kinematischen Kontakt dazwischen dienen.


     
    12. Kugellageranordnung (40) nach Anspruch 11, bei der die Materialien des Käfigs eines von einem geformten, synthetischen Harz, selbstschmierenden Material, verstärkt mit Kohlefaser, Molybdändisulfid oder Polytetrafluorethylen (PTFE) aufweisen.
     
    13. Kugellageranordnung (40) nach Anspruch 11, bei der der Schmiermittelvorratsbehälter in einer Menge ausreichend gemacht wird, die durch das als Schmiermittelvorratsbehälter wirkende Käfigmaterial, die Grenzflächenspiele, die bestehenden Umgebungsbetriebsbedingungen und solche Lager-Kinematik-Beziehungen, die zwischen den Käfigsegmenten, den Ringen und den Kugellagern bestehen, gesteuert wird.
     
    14. Kugellageranordnung (40) nach Anspruch 11, bei der die Lagerringe (42, 44) Innenflächen haben, die für optimale Reibung und Verschleiß modifiziert sind, indem sie galvanisch beschichtet und mit einer aufgebrachten Polytetrafluorethylen (PTFE)-Versiegelung veredelt sind.
     
    15. Kugellageranordnung (40) nach Anspruch 11, die ferner synthetische Kohlenwasserstoff-Grundöle mit Verschleißschutzadditiven zur Anwendung bei langsamer bis mittlerer Geschwindigkeit in Bezug auf die Kugellager enthält.
     
    16. Kugellageranordnung (40) nach Anspruch 15, bei der die synthetischen Kohlenwasserstoff-Grundöle Polyalphaolephine (PAO) oder mehrfach alkylierte Cyclopentane (MACs Multiply-Alkylated Cyclopentanes) aufweisen und die Verschleißschutzadditive Bleinapthenat oder Tricresylphosphat aufweisen und ferner Fette und Öle nach Bedarf in Abhängigkeit von zulässigem Widerstandslagerdrehmoment, Betriebstemperatur, Drehzahl und Drehmomentgeräusch enthalten.
     
    17. Kugellageranordnung (40) nach Anspruch 15, bei der das Käfigmaterial eines aus einem geformten, synthetischen Harz mit hinzugefügten Füllstoffen zur Erhöhung der Festigkeit des Käfigs und zur Verringerung seiner Verschleißrate aufweist.
     
    18. Kugellageranordnung (40) nach Anspruch 1, wobei der mit Taschen versehene Käfig (156; 256; 356) für die Kugellager (48) aus Materialien geformt ist, die so ausgewählt sind, dass sie als Schmiermittelvorratsbehälter dienen, um alle Lagerkomponenten-Grenzflächen mit jeglichem benötigten Schmiermittel zu versorgen, und wobei im Fall einer übermäßigen thermisch induzierten Dimensionsänderung aufgrund einer Kombination aus einer übermäßigen Fehlanpassung zwischen den Wärmeausdehnungskoeffizienten zwischen der Laufbahn (52) und den Käfigmaterialien und einer extremen Betriebstemperatur die Käfigkugeltaschen (156; 256; 356) so ausgewählt sind, dass sie einen ovalen Querschnitt aufweisen.
     
    19. Kugellageranordnung (40), aufweisend (a) einen oberen kreisförmigen Ring (42) und einen unteren kreisförmigen Ring (44), wobei jeder Ring Kugellagerlaufbahnen (52) aufweist, die einander zugewandt sind, und (b) einen Kugellagerkäfig, der eine Mehrzahl von Kugellagern (48) trägt, der zwischen dem oberen Ring und dem unteren Ring angeordnet ist und der es den Kugellagern ermöglicht, sich in den Laufbahnen zu befinden, und wobei der Käfig eine Mehrzahl von bogenförmigen Segmenten (146; 246; 346) aufweist, die zusammen einen Kreis bilden, und wobei jedes der Käfigsegmente (146; 246; 346) Enden (64) hat, die jeweils benachbarte der Segmente berühren, und wobei jedes der Segmentenden (64) abgerundet ist, um jegliche radial übertragenden Kräfte und jeglichen Käfigverschleiß zwischen benachbarten der Segmente zu minimieren, und wobei die Abrundungen der Enden jeweils mit zwei Radien (64a, 64b) versehen sind, die ihre jeweiligen Käfigsegmente beenden, um jegliche derartige radial übertragende Kräfte und jeglichen derartigen Käfigverschleiß zwischen den benachbarten der Segmente zu minimieren.
     
    20. Kugellageranordnung (40) nach Anspruch 19, wobei der Käfig (46) mit Taschen (156; 256; 356) für die Kugellager (48) aus Materialien gebildet ist, die so ausgewählt sind, dass sie als Schmiermittelvorratsbehälter dienen, um alle Lagerkomponenten-Grenzflächen mit jeglichem benötigten Schmiermittel zu versorgen, und wobei im Fall einer übermäßigen thermisch induzierten Dimensionsänderung aufgrund einer Kombination aus einer übermäßigen Fehlanpassung zwischen den Wärmeausdehnungskoeffizienten zwischen den Laufbahn- und den Käfigmaterialien und einer extremen Betriebstemperatur die Käfigkugeltaschen so ausgewählt sind, dass sie einen ovalen Querschnitt aufweisen, dessen Hauptachse entlang seiner Umfangsrichtung verläuft und dessen Halb-Hauptachsen-Abmessung, a, gemäß der folgenden Formel berechnet ist:

    wobei

    b = dKugelVerhältnis, mm

    dKugel = Kugeldurchmesser, mm

    Verhältnis = 1,025 - 1,10, mm

    d = Durchmesser der Lagerteilung, mm

    nSegment = Anzahl der Käfigsegmente pro Lagerreihe

    Twarm = extreme Betriebs-Warmtemperatur, °C

    Tkalt = extreme Betriebstemperatur kalt, °C

    αKäfig = thermischer Ausdehnungskoeffizient für Kugelkäfigmaterial in Umfangsrichtung, 1/°C

    αLaufbahn = thermischer Ausdehnungskoeffizient für Laufbahnmaterial, 1/°C

    tol = Fertigungstoleranz des Taschendurchmessers, mm.


     


    Revendications

    1. Ensemble de roulement à billes (40) comprenant (a) des bagues supérieure (42) et inférieure (44) ayant des chemins de roulement de roulement à billes (52) disposés en regard l'un de l'autre et (b) un élément de retenue de roulement à billes (46) qui supporte une pluralité de roulements de type billes (48), qui est pris en sandwich entre lesdites bagues supérieure (42) et inférieure (44) et qui permet auxdits roulements de type billes (48) de demeurer au sein desdits chemins de roulement (52), l'amélioration dans laquelle ledit élément de retenue (46) comprend une pluralité de segments courbés (146 ; 246 ; 346) qui ensemble forment un cercle, dans lequel
    ledit élément de retenue (46) est fourni avec des cavités (156 ; 256 ; 356) pour lesdits roulements de type billes (48)
    et
    lesdites cavités pour bille de l'élément de retenue (156 ; 256 ; 356) sont choisies pour avoir une section transversale ovale avec son grand axe le long de sa direction circonférentielle, dans laquelle sa dimension de demi-grand axe, a, est calculée selon la formule ci-dessous :

    b = dballratio, en mm

    dball = diamètre de bille, en mm

    ratio = 1,025 - 1,10, en mm

    d = diamètre de pas du roulement, en mm

    nsegment = nombre de segments de l'élément de retenue par rangée de roulement

    Thot = température extrême de fonctionnement, valeur haute, en °C

    Tcold = température extrême de fonctionnement, valeur basse, en °C

    αretainer = coefficient de dilatation thermique du matériau de l'élément de retenue des billes le long de la direction circonférentielle, en °C-1

    αraceway = coefficient de dilatation thermique du matériau du chemin de roulement, en °C-1

    tol = tolérance de fabrication diamétrale de la cavité, en mm.


     
    2. Ensemble de roulement à billes (40) selon la revendication 1, dans lequel chacun desdits segments de l'élément de retenue (146 ; 246 ; 346) a des extrémités (64) respectivement en contact avec des extrémités adjacentes desdits segments et dans lequel chacune desdites extrémités de segment (64) est arrondie de sorte à minimiser toute force de transfert radiale et toute usure de l'élément de retenue entre les extrémités adjacentes desdits segments.
     
    3. Ensemble de roulement à billes (40) selon la revendication 2, dans lequel les arrondis desdites extrémités (64) sont chacun pourvus de deux rayons (64a, 64b) terminant leurs segments de l'élément de retenue respectifs (146 ; 246 ; 346) pour minimiser toute force de transfert radiale et toute usure de l'élément de retenue entre lesdits extrémités adjacentes desdits segments.
     
    4. Ensemble de roulement à billes (40) selon la revendication 1, dans lequel le nombre desdits segments courbés de l'élément de retenue (146 ; 246 ; 346) est choisi en conséquence pour réduire tout effet thermique induit sur le couple, le couple de frottement par glissement et les effets dynamiques induits entre lesdits segments de l'élément de retenue, lesdites bagues et lesdits roulements de type billes.
     
    5. Ensemble de roulement à billes (40) selon la revendication 4, dans lequel chacun desdits segments de l'élément de retenue (146 ; 246 ; 346) a des extrémités (64) respectivement en contact avec des extrémités adjacentes desdits segments et dans lequel chacune desdites extrémités de segment est arrondie de sorte à minimiser toute force de transfert radiale et toute usure de l'élément de retenue entre les extrémités adjacentes desdits segments.
     
    6. Ensemble de roulement à billes selon la revendication 5, dans lequel les arrondis desdites extrémités (64) sont chacun pourvus de deux rayons (64a, 64b) terminant leurs segments de l'élément de retenue respectifs (146 ; 246 ; 346) pour minimiser toute force de transfert radiale et toute usure de l'élément de retenue entre lesdites extrémités adjacentes desdits segments.
     
    7. Ensemble de roulement à billes (40) selon la revendication 1, dans lequel :

    lesdites bagues supérieure (42) et inférieure (44) incluent chacune des épaulements (54a ; 54b) entourant lesdits chemins de roulement (52) ;

    chacun desdits segments (146 ; 246 ; 346) inclut des cavités (156 ; 256 ; 356) pour retenir lesdits roulements de type billes (48) ; et lesdites cavités (156 ; 256 ; 356) ont des coins (60 ;160 ; 260 ;360) sur lesquels lesdits roulements de type billes (48) demeurent, lesdits coins des cavités (60 ; 160 ; 260 ; 360) empêchant lesdits segments de l'élément de retenue (146 ; 246 ; 346) d'entrer simultanément en contact avec lesdits épaulements de chemin de roulement de bague inférieure (54b) et lesdits épaulements de chemin de roulement supérieurs (54a).


     
    8. Ensemble de roulement à billes (40) selon la revendication 7, dans lequel :

    lesdits roulements de type billes (48) et lesdites cavités de l'élément de retenue (156 ; 256 ; 356) ont des interfaces entre eux ; et

    lesdites cavités de l'élément de retenue (156 ; 256 ; 356) ont des fentes (262) à l'intérieur de celles-ci pour augmenter la compatibilité entre lesdites interfaces billes/cavités afin d'aider à la réduction de tout effet dynamique induit entre lesdits roulements de type billes et lesdites cavités.


     
    9. Ensemble de roulement à billes (40) selon la revendication 1, dans lequel
    lesdits segments de l'élément de retenue (146 ; 246 ; 346) sont fournis avec des cavités (156 ; 256 ; 356) pour retenir lesdits roulements de type billes (48),
    lesdites bagues (42, 44) incluent des chemins de roulement (52) pour lesdits roulements de type billes (48), des lubrifiants solides sont inclus dans lesdites cavités (156 ; 256 ; 356),
    lesdits chemins de roulement de bague de roulement (52) ont des surfaces électroplaquées, et
    un matériau d'étanchéité de polymère organique est appliqué auxdites cavités et auxdits chemins de roulement pour optimiser tout frottement et usure entre eux.
     
    10. Ensemble de roulement à billes (40) selon la revendication 9, dans lequel lesdits chemins de roulement (52) sont recouverts d'une couche mince moléculaire comprenant un polyéther perfluoré ou lesdits chemins de roulement sont recouverts d'une couche mince moléculaire d'un polyéther perfluoré.
     
    11. Ensemble de roulement à billes (40) selon la revendication 9, dans lequel :

    lesdits roulements de type billes (48) et lesdites cavités de l'élément de retenue (156 ; 256 ; 356) ont des interfaces de composant de roulement entre eux ; et

    ledit élément de retenue (46) est formé à partir de matériaux choisis pour agir en tant que réservoir de réalimentation en lubrifiant afin de fournir tout lubrifiant nécessaire à toutes lesdites interfaces de composant de roulement via un contact cinématique entre elles.


     
    12. Ensemble de roulement à billes (40) selon la revendication 11, dans lequel lesdits matériaux de l'élément de retenue comprennent un élément parmi un matériau auto-lubrifié, de résine synthétique, moulé, renforcé par de la fibre de carbone, du disulfure de molybdène et du polytétrafluoroéthylène (PTFE).
     
    13. Ensemble de roulement à billes (40) selon la revendication 11, dans lequel ledit réservoir de réalimentation en lubrifiant est rendu suffisant en quantité, contrôlé par ledit matériau de l'élément de retenue agissant comme réservoir de réalimentation en lubrifiant, les jeux d'interface, les conditions de fonctionnement environnementales existantes et les relations cinématiques de roulement telles qu'elles existent entre lesdits segments de l'élément de retenue, lesdites bagues et lesdits roulements de type billes.
     
    14. Ensemble de roulement à billes (40) selon la revendication 11, dans lequel lesdites bagues de roulement (42, 44) ont des surfaces internes qui sont modifiées pour un frottement optimal et une usure optimale en étant électroplaquées et améliorées par l'application d'une couche d'étanchéité en polytétrafluoroéthylène (PTFE).
     
    15. Ensemble de roulement à billes (40) selon la revendication 11 comprenant en outre des huiles à base d'hydrocarbures synthétiques avec des additifs de protection contre l'usure pour son application dans une utilisation à vitesse lente à modérée par rapport auxdits roulements à billes.
     
    16. Ensemble de roulement à billes (40) selon la revendication 15, dans lequel lesdites huiles à base d'hydrocarbures synthétiques comprennent des polyalphaoléfines (PAO) ou des cyclopentanes multi-alkylés (MACs pour Cyclopentanes Multiply-Alkylated) et les dits additifs de protection contre l'usure comprennent du napthénate de plomb ou du phosphate de tricrésyle et comprennent en outre des graisses et des huiles selon les besoins en fonction du couple de roulement de résistance admissible, de la température de fonctionnement, de la vitesse et du bruit de couple.
     
    17. Ensemble de roulement à billes (40) selon la revendication 15, dans lequel ledit matériau de l'élément de retenue comprend un élément parmi une résine synthétique moulée avec des charges ajoutées pour une résistance augmentée dudit élément de retenue et pour une réduction du taux d'usure de celui-ci.
     
    18. Ensemble de roulement à billes (40) selon la revendication 1, dans lequel ledit élément de retenue (46) tel que fourni avec des cavités (156 ; 256 ; 356) pour lesdits roulements de type billes (48) est formé à partir de matériaux choisis pour agir en tant qu'un réservoir de réalimentation de lubrifiant afin de fournir tout lubrifiant nécessaire à toutes lesdites interfaces de composant de roulement et, dans le cas de changement dimensionnel thermique induit excessif dû à une combinaison de décalage excessif entre les coefficients de dilatation thermique entre ledit chemin de roulement (52) et lesdits matériaux de l'élément de retenue, et de température de fonctionnement extrême, lesdites cavités pour bille de l'élément de retenue (156 ; 256 ; 356) sont choisis pour avoir une section transversale ovale.
     
    19. Ensemble de roulement à billes (40) comprenant (a) une bague circulaire supérieure (42) et une bague circulaire inférieure (44), chacune desdites bagues ayant des chemins de roulement de roulement à billes (52), lesquels chemins de roulement sont disposés en regard l'un de l'autre et (b) un élément de retenue de roulement à billes qui supporte une pluralité de roulements de type billes (48), qui est pris en sandwich entre ladite bague supérieure et ladite bague inférieure et qui permet auxdits roulements de type billes de demeurer à l'intérieur desdits chemins de roulement et dans lequel ledit élément de retenue comprend une pluralité de segments courbés (146 ; 246 ; 346) qui forment ensemble un cercle, et dans lequel chacun desdits segments de l'élément de retenue (146 ; 246 ; 346) a des extrémités (64) respectivement en contact avec des extrémités adjacentes desdits segments et dans lequel chacune desdites extrémités de segment (64) est arrondie de sorte à minimiser toute force de transfert radiale et toute usure de l'élément de retenue entre les extrémités adjacentes desdits segments, et dans lequel les arrondis desdites extrémités sont chacun pourvues de deux rayons (64a, 64b) terminant leurs segments de l'élément de retenue respectifs afin de minimiser toute force de transfert radiale et toute usure de l'élément de retenue entre lesdites extrémités adjacentes desdits segments.
     
    20. Ensemble de roulement à billes (40) selon la revendication 19, dans lequel ledit élément de retenue (46) est fourni avec des cavités (156 ; 256 ; 356) pour lesdits roulements de type billes (48) et est formé à partir de matériaux choisis pour agir en tant que réservoir de réalimentation de lubrifiant afin de fournir tout lubrifiant nécessaire à toutes lesdites interfaces de composant de roulement et, dans le cas d'un changement dimensionnel thermique induit excessif dû à une combinaison de décalage excessif entre les coefficients de dilatation thermique entre ledit chemin de roulement et lesdits matériaux de l'élément de retenue, et de température de fonctionnement extrême, lesdites cavités pour bille de l'élément de retenue sont choisies pour avoir une section transversale ovale avec son grand axe le long de sa direction circonférentielle dans laquelle sa dimension de demi-grand axe, a, est calculée selon la formule ci-dessous :

    b = dballratio, en mm

    dball = diamètre de bille, en mm

    ratio = 1,025 - 1,10, en mm

    d = diamètre de pas du roulement, en mm

    nsegment = nombre de segments de l'élément de retenue par rangée de roulement

    Thot = température extrême de fonctionnement, valeur haute, en °C

    Tcold = température extrême de fonctionnement, valeur basse, en °C

    αretainer = coefficient de dilatation thermique du matériau de l'élément de retenue des billes le long de la direction circonférentielle, en °C-1

    αraceway = coefficient de dilatation thermique du matériau du chemin de roulement, en °C-1

    tol = tolérance de fabrication diamétrale de la cavité, en mm.


     




    Drawing




















    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description