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FLEXIBLE BUSHES FLEXIBLE BUSHES

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DESCRIPTION

A flexible bush has an elastomeric element enclosed between an outer sleeve and a centre axisintended to replace a greased bush.The improvements achieved in industry due to the use of elastic bushes have been justlycompared to the progress achieved in the past by the use of ball joints. In fact, theimprovementsachieved by the latter by reducing friction and play considerably and reducing wear an noise,have been taken even further by elastomeric rubber bushes which eliminate play completelyand isolate high frequency vibrations.

TRANSCRIPT

  • FLEXIBLEBUSHESFLEXIBLEBUSHES

  • I - GENERALI.1 The operation of a flexible bushI.2 Static characteristics

    I.2.1 Radial characteristicsI.2.2 Torsional characteristicsI.2.3 Axial characteristicsI.2.4 Conical characteristics

    I.3 Dynamic characteristicsI.3.1 Dynamic loadsI.3.2 Torsion amplitudes

    II - PRINCIPAL TYPES OFFLEXIBLE BUSHESII.1 Simple bushesII.2 Flanged bushesII.3 Laminated bushesII.4 Void bushesII.5 Pivot bushesII.6 Spherical bushesII.7 Other bushes

    III - OUTER SLEEVE ANDCENTRE AXISIII.1 Materials usedIII.2 Protection during storageIII.3 Tolerance on LengthIII.4 Tolerances on Diameter

    IV - THE SELECTION OFA FLEXIBLE BUSH

    V - AN EXAMPLE OF A SELECTION

    VI - INSPECTION OFFLEXIBLE BUSHESVI.1 Dimensional controlVI.2 Control of stiffnessVI.3 Control of bonding

    VII - CATALOGUE OFFLEXIBLE BUSHES

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  • - GENERAL

    A flexible bush has an elastomeric element enclosed between an outer sleeve and a centre axisintended to replace a greased bush.

    The improvements achieved in industry due to the use of elastic bushes have been justlycompared to the progress achieved in the past by the use of ball joints. In fact, theimprovementsachieved by the latter by reducing friction and play considerably and reducing wear an noise,have been taken even further by elastomeric rubber bushes which eliminate play completelyand isolate high frequency vibrations.

    I.1 - THE OPERATION OF A FLEXIBLE BUSH

    I

    3

    F L E X I B L E B U S H E S

  • I.2.1 - Radial characteristicsThe application of a radial force FR causes an elastic eccentricity X by compression of theelastomer on one side and stretching of the other side.The bush is characterised by the permissible radial static force and by the correspondingeccentricity.In practice, the permissible radial static forces are estimated by taking the stress rate on thesurface area S of the rectangle which represents the projection of part of the elastomer whichis in contact with the internal tube.

    FR FR NStress rate = ____ = ______ ( ___ )S d1 x l m2

    lThe permissible stress is a function __ of the bush and of the specific properties of theelastomer. D

    It is clear that the permissible deformation for a given radial force will be linked in practice tothe thickness of the elastomer.

    D1 - d1e = _______

    2

    I.2.2 - Torsional characteristicsThe application of a torque to the centre axis of revolution of a bush causes an angulardisplacement a. This displacement produces a torsional reaction expressed in N.m.The bush is characterised by its maximum torsion angle and by the correspondingcompensating torque.In practice, the permissible torsion angles are of the order of 20 to 30. The maximumpermissible static torque can be calculated on the basis of the stress rate at the point of contactbetween the internal tube and the elastomer.

    d1 l d1 and 1 are in cmC = t x pi _______ where C is in cm.kg # 0.1 N.m

    2 t is in daN/cm

    I.1 - STATIC CHARACTERISTICS

    4

    FR

    D D1 d d

    e1

    l

    L

    x

  • I.2.3 - Axial characteristicsWhen the external tube is fixed, the application of an axial force Fa on the internal tubewill cause an elastic displacement y parallel to the axis of the bush, by shearing of theelastomer.The bush is characterised by the permissible axial load and by the corresponding elasticdisplacement.In practice, the permissible static axial loads are estimated by taking the stress rate atthe internal tube.Fa = pi x d1 x 1 x t where d1 and 1 are in cm and Fa in daN and t is in daN/cm2

    The permissible static deflection is a function of the radial thickness of the elastomer.

    D1 - d1y = k. ________ (K being between 0.20 and 0.50).

    2

    The axial breaking load of a bonded part is of the order of 10 times the permissible static load.

    Note:A Prestressed bush which is not fully bonded must not be subjected to a static axial load.

    I.2.4 - Conical characteristicsThe application of a torque whose axis is perpendicular to the axis of rotation of the bush willcause an angular deformation .This deformation will in turn produce a compensating elastic torque expressed in N.m.The bush is characterised by the permissible conical angle and by the correspondingcompensating torque.In practice, the permissible conical angles are of the order of a few degrees. They vary greatlywith the slenderness ratio l of the part.__

    D

    5

    l

    D1d1

    y

    Fa

    d1

    l

  • I.3.1 - Dynamic loads

    For dynamic loads, the following corrections must be added to the static loads provided in thecatalogue :

    For infrequent forces of very short duration (shocks), the loads can be doubled. In the case of continuing periodic forces, the loads must be multiplied by a reduction

    coefficient which is a function of the frequency of the forces.

    I.3.2 - Torsion amplitudes

    The torsion amplitudes provided in the catalogue must be multiplied by a reduction coefficient which is a function of the frequency of the oscillations.

    I.3 - DYNAMIC CHARACTERISTICS

    6

    Hertz

    cycles/minute

    load reduction cfficientas a function of frequency

    acci

    den

    tal l

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    1,0

    0,9

    0,8

    0,7

    0,6

    0,5

    0,4

    0,3

    0,2

    0,1

    100 200 300 400 500 600 700 800 900 1000

    Hertz

    cycles/minute

    angular amplitude coefficient as afunction of the frequency of oscillations

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    ptio

    nal

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    ns

    1,0

    0,9

    0,8

    0,7

    0,6

    0,5

    0,4

    0,3

    0,2

    0,1

    100 200 300 400 500 600 700 800 900 1000

    5 1510

    5 1510

  • - PRINCIPAL TYPES OFFLEXIBLE BUSHES

    The lateral stop only comes into operation when the bush is forced off centre by a radial load.This causes the stop to protrude, thus ensuring an anti-noise role at the limit of axialmovement.

    II

    II.1 - SIMPLE BUSHES

    FLEXIBLOC (fig. 1) - FULLY BONDEDThis is a bush made up of 2 concentric tubes between which of elastomer is bonded. Underthe effect of external forces or torques, the relative movement of the tubes will cause an elasticdeformation of the elastomer. By consulting the service conditions, a bush should be chosenwhich will remain within its elastic operational limits.

    SILENTBLOC (fig. 2) - PRESTRESSEDThis is a bush made up of 2 concentric tubes between which a ring of adhrite elastomer isinserted by force. Under the effect of external forces or torques, the relative movement of thetubes will cause an elastic deformation of the elastomer. Above a certain value the adherite willslide in the tubes.

    These simple bushes are considered to have lateral stops (fig. 3) when the elastomer protrudesfrom the external tube in the form of a support surface with various profiles.

    The rigidity k1 is equal to k2 if the travel is less than a, and it becomes greater than k2 whenthe travel is greater than a.

    II.2 - FLANGED BUSHES

    In this type of bush, one of the tubes is flanged.

    7

    k1 k2

    a

    k2k1

    k 1 = k 2

    forc

    e

    displacementa

    Fig. 3Fig. 2Fig. 1

  • II.3 - LAMINATED BUSHES

    II.4 - VOID BUSHES

    II.5 - PIVOT BUSHES

    This type of bush has a thin metallic tube between the internal tube and the external tube. Theobject is to have a higher stiffness radially while keeping practically the same stiffness in torsion.The lamination of a bush also helps to decrease the work rate of the elastomer under high radialloads.

    FLUIDBLOC :This type of bush is intended to offer minimum resistance to torsion. The elastomer is bondedto only one of the armatures, and a suitable permanent lubricant ensures the lubricationbetween the elastomer and the second armature ensures a very low torsional resistance. Sealsare provided at each end to prevent the lubricant from coming out and stop impurities fromgetting in. Resistance to axial force is provided by a flange in the elastomer which bears againstthe side of the outer sleeve, the force being transmitted by a lateral washer.

    A void bush is designed to have radial stiffness which are very different at 90 to each other. Thedifference in rigidity is governed by the size of the voids, which may or may not run the wholelength of the bush.

    8

  • II.6 - SPHERICAL BUSHES

    II.7 - OTHER BUSHES

    SPHERIFLEX :In this bush, the outer sleeve and centre axis are spherical, which enables the bush to resistrelatively high radial and axial loads and to obtain a circular rigidity which is independent of theaxis of rotation.

    CONICAL BUSH :This takes the form of a rubber sleeve whose external surface is a truncated, and whichsurrounds a cylindrical internal part to which it adheres strongly by high radial expansion.

    Assembly in pairs, in a housing made up of two truncated cones placed small end to small end.By axial pressure, a high compression is created which ensures the external adherence of therubber and causes lateral cushions to form at each end of the housing. These cushions ensureresistance to axial forces.

    PRESTRESSED BUSHES with turned down sides :For the same dimensions, this type of bush provides a radial load capacity which is superior tothat of the classic prestressed. In addition, versions of relatively short length permit conicalmovement more easily (reduced torque and increased angle).

    9

  • 10

    - OUTER SLEEVE AND CENTREAXIS

    III

    III.1 - MATERIALS USED

    III.2 - PROTECTION DURING STORAGE

    III.3 - LENGTH TOLERANCES

    III.4 - DIAMETER TOLERANCES

    In general, the outer sleeve and centre axis of flexible bushes are made of :

    Mild steel or polyamide for the external outer sleeve.

    Medium carbon steel for the centre axis.

    The reason for the difference has to do with the method of fixation onto the internal armature,which is usually done by forcing from one end. The armature must therefore be both strong andnot too thin, to avoid buckling.

    On the internal diameter d: H10

    To avoid corrosion of the steel parts, the parts are protected by a layer of phosphate whichgives them a grey appearance, the whole being protected by a layer of oil.

    To ease removal of fixing botts, the internal tubes are also protected on the interior by a layerof phosphate. This protection is good for storage, but it does not constitute a tropicalisedprotection, nor is it intended to resist saline mist.

    Length L (internal tube) : 0.1mm

    Length l (external tube) : JS 15, according to NF E02 100-1 and NF E02 100-2

    L - l Longitudinal overhang : _____ 0.4 mm

    2

    dmm

    H10+ 0.058+ 0

    + 0.048+ 0

    + 0.070+ 0

    + 0.084+ 0

    + 0.1+ 0

    3 to 6 6 to 10 10 to 18 18 to 30 30 to 50

    On the external diameter D :

    D 25mm

    + 0.05+ 0

    + 0.1+ 0

    + 0.15+ 0

    25 < D 40mm

    D > 40mm

    Recommended tolerance for fitting into a bored hole : boring D : N9

    Dmm

    N9 - 0- 0.043

    - 0- 0.052

    - 0- 0.062

    - 0- 0.074

    - 0- 0.087

    10 to 18 18 to 30 30 to 50 50 to 80 80 to 120

  • In order to specify a bush correctly for a given application, the following criteria must bedetermined :

    Basic dataFor each of the 4 characteristics of the part (axial, radial, torsion or conical), the following valuesmust be taken into account :- The maximum static values (of force and/or of deflection) to which the part is subjected.- The maximum dynamic values and their frequencies.

    Fundamental parametersDepending on the application, determine from the basic data the major fundamentalparameter(s) which govern the choice of the bush to be used.

    DimensionsThe fundamental parameters enable you to consult the catalogue for the range of dimensionsof various bushes.

    StiffnessThe final selection of the bush will depend on the required stiffness for the application. Inparticular, length, diameter and the thickness of the elastomer required for the desired bushwill be determined.

    Environmental conditionsMost of our standard bushes are in natural rubber. This has been chosen because of its gooddynamic qualities.In normal conditions of use, the types of rubber used guarantee a good life and limit creep inparticular.The following conditions of use are considered abnormal:- temperatures above 70 C- prolonged contact with aggressive fluids- aggressive environments, such as oil or petrol- prolonged contact with acids or alkalis- aggressive atmospheres (e.g. ozone, chlorine)Use in this conditions can accelerated ageing of the bushes, and cause the degradation or eventhe destruction of the rubber.An abnormally aggressive environment can, in particular, increase the deformation of the bush(by creep).Flexible bushes can be made with special elastomers which are capable of surviving theabnormal conditions mentioned above and enabling the bushes to perform well.Our technical services are at your disposal to reply to your questions about the propertiesof our various elastomers.

    - AN EXAMPLE OF ASELECTION

    For the bushes of a vibrating carpet.Weight : 120 daN. Number of fixing points : 6Angle of movement : 2. Frequency : 600 cycles/mn = 10 HzRadial load per bush : # 20 daN (evenly loaded).

    2Amplitude reduction coefficient at 10 Hz : m = 0.18. Torsion angle: _____ = 110.18In this case, the axial and conical parameters are not of major importance in the selection of thebushes.

    Since the fixing diameter of the connecting rods is 10 mm, we would select reference 561 205from the bush catalogue.

    d = 10 mm D = 22 mm L = 17 mm l = 15 mm Radial load = 40 daNMaximum torsion angle = 25

    Therefore, for the given application we would use : 12 Flexibloc 561205 bushes.

    11

    - THE SELECTION OF A FLEXIBLE BUSH

    IV

    V

  • - INSPECTION OFFLEXIBLE BUSHES

    VI

    VI.1 - DIMENSIONAL CONTROL

    VI.1.1 - External diameter DThis is checked in the region of the middle of length L by means of a minimum-maximumgauge.

    VI.1.2 - Internal diameter dThis is checked with a standard length minimum-maximum gauge.

    L - 1VI.1.3 - Longitudinal overhang ____

    2

    This is checked with a minimum-maximum gauge.The main purpose of the tolerance on this overhang is to maintain adequate clearance for axialelastic displacement which is an important dimension.

    VI.1.4 - EccentricityThe eccentricity is the average distance between the axes of the internal and external tubes. Itis measured in the following manner:

    The difference in the readings of a comparator applied to the middle of the length l of theexternal tube, when the part is turned through a full rotation about the axis of the internal tube,represents the eccentric circle which is equal to twice the eccentricity.

    In order to take a possible conical deformation into account, one can take the average of twomeasurements made at the two extremities of the external tube.

    12

    comparator

    comparator

    L

    l

    Dde

  • For a given bush, the four stiffness characteristics are linked. It therefore sufficient to measureone of them. The most convenient is the axial shear stiffness (excluding the effect of any axialcushions).

    The selected test load P will be the maximum static load Fa, in order on the one hand to operatein the linear part of the stiffness curve, and on the other to avoid having a measured value whichis of the same order as any unaccuracies. The test should be done on a frictionless guidedassembly.

    A pre-load of a few kilograms is first selected to zero the comparator the load P = Fa is thenapplied, for which the deflection y is noted.

    In the case of current manufacture, a tolerance of 25% or 30% is generally accepted for thisdeflection.

    Vertically guided assembly on a tension-compression machine.

    VI.2 - CONTROL OF STIFFNESS

    VI.3 - CONTROL OF BONDING

    The only test possible is a test of samples taken to breaking point. This test is done in the axialdirection. A minimum for the value of the load at rupture of the order of 10 times the static axialload can be accepted.

    13

    P

  • SIMPLE BUSHES

    FLEXIBLOC - Fully Bonded : The elastomer is bonded to the 2 concentric tubes,Parts Number 560 ***, 561 ***

    SILENTBLOC - Prestressed Elastomer : The ring of adherite is inserted by forcebetween the 2 concentric tubes,Parts Number 861***, 862***, 864***

    BL : Bushes with a lateral stop.

    FLEXIBLOC AND SILENTBLOC

    dmm

    6

    8

    910

    16161620161616162020322122

    1414242217242528171923.22117

    12122016152022251515181715

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    Dmm

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    Obs StaticLoaddaN

    Deflectionmm

    Maxangle

    degrees

    StaticLoaddaN

    Deflectionmm

    Maxangle

    degrees

    Reference

    RADIAL TORSION CONICALAXIAL

    The references kept in stock are written in bold.

    14

    Torsionalangle

    Axialload

    Radialload

    Deflection underaxial load

    Deflection underradial load

    Conical angle

    Dd

    L

    l

  • 15

    The references kept in stock are written in bold.

    dmm

    10

    11.312

    12.0414

    14.316

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    19232430333422242226273230.2232834384454242734283849303030424046.576.0325282833454951.5545844544428283030304242334648547069.8343026282830

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    BL

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    405590

    100110

    555070658080

    1104555

    100120145145550

    35908050

    120130110110

    70210190140100

    60120

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    5080

    12050

    150100130170250190300370

    30200

    70120140

    80

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    3020504020202020252010202015152030302525303030252515253020205

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    15351540703525252525304035254050959545205050256060404025353050503050454080

    16580

    18580807050452550552570656080

    100125200190

    153535505040

    0.80.40.41.50.60.30.20.81.51.510.80.30.210.80.40.40.60.41.50.40.41.51.61.51.50.61.11221.11.80.411.50.710.510.70.72.51.10.41.21.20.41.90.4220.50.61.10.90.40.50.321.60.3

    612313533352234311174373463422643433211111125755733422211112553

    561206861112561112561207861114861607561209561445561613561150561424561518561103861118561212561213864105861197561250861611561283861613861614561446561224561302561341864801561395560034561122561677561120561227861128561747561269861132561493864109561748561458561617561594561303861618561377561304861619561305861620561307561492561340864403561309861251861834561348861136561313561312861138

    Dmm

    Lmm

    lmm

    Obs StaticLoaddaN

    Deflectionmm

    Maxangle

    degrees

    StaticLoaddaN

    Deflectionmm

    Maxangle

    degrees

    Reference

    RADIAL TORSION CONICALAXIAL

  • dmm

    16

    18

    20

    22

    24

    2628

    3032

    3232323232323636404040405252343434343434364270383838383838384042424445.154850524040424242444848485844484848484852666666505252

    3254545966763843404050543448333336546671463858425959767681904542424542465066458650559658445893586636556666

    118108

    666676

    1286666

    2850505560703535323232503040303032506065403545385555707075843838383838334060408045509048405085486034506060

    110100

    565670

    1206060

    0.050.050.050.050.050.10.10.10.80.60.60.5110.10.050.050.30.050.050.040.12.50.20.150.040.20.040.040.10.150.30.080.50.80.20.510.050.060.060.050.020.080.30.30.1510.20.050.050.150.060.070.11.5110.070.150.06

    BL

    BL

    BL

    BL

    BL

    130330330400450500

    9090

    20095

    135250

    7090

    120150160600490540220100225230300410400630700600

    70300165210300

    65155300250850340400

    1100125160350560215500315420400540

    1500800500350850

    1900600600

    202020202020303030

    55

    354040202020122020203050252020152020152525202525

    55

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    51520202020203040

    530201020

    65220220260300180

    454545

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    1203050607580

    100320360145

    50100

    7550

    270200420465200

    3590809060

    25150130560170200730

    60110120370

    -160160210190270900500140100320

    1000260300

    0.40.40.40.40.41.50.50.51.5--33.541.10.40.411.51.50.40.54111.511.51.510.61.50.531.6-0.730.41.50.40.410.81.520.7-10.50.51.10.520.73.5332.52.20.3

    3111117724437743311117532111112434244531331322341332313746113

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    Dmm

    Lmm

    lmm

    Obs StaticLoaddaN

    Deflectionmm

    Maxangle

    degrees

    StaticLoaddaN

    Deflectionmm

    Maxangle

    degrees

    Reference

    RADIAL TORSION CONICALAXIAL

    16

    The references kept in stock are written in bold.

  • dmm

    32

    3436

    38

    42

    44.4546

    505658

    60

    626870

    80

    90

    110

    120125138150

    170190210

    56567050586064646678787878788076.2808680939395

    105110140105105120120120140140140140145170175160160160192185185210230260

    55116

    7645

    1306076

    13560668686

    140140

    856386

    11083

    250132

    9087

    182182120120120182120

    989898

    182170105205190190185130210240270270300

    50108

    7039.5

    1205570

    12555608080

    130130

    796080

    10079

    170117

    8390

    170170110110115170110

    989898

    170145105190170170184124209239269258290

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    SP

    31010001100

    2001900

    400900

    2400450680

    10001270200028001400

    70015001400150026002000160020004000540025002500300045003000300030002300540055001500750060004000430055005500650080008500

    10500

    303025

    6203020203030102020201530152015151515151515151515151510

    81015151012121212101010101010

    150650190100

    1000200450

    1300220340200630400

    1500-

    100-

    700150

    1400200

    -200400360250250300450300

    1800--

    540550

    -750600400430

    -550650800850

    1000

    0.70.72.32.510.70.51.50.711.60.822-0.2-1.50.721.2-1.20.820.80.80.90.80.82--0.80.8-0.90.70.60.4-0.40.50.40.40.4

    7321173177131133311

    0,323211111112211151111311111

    861638861639561703561141861182861640861183861184861642862601561701862101561702862102862111862140862137862422862614561901862444862646862435862510862512862421561657862434862480561658561009561043862481862414862627561956862513561928561938561913862810561916561925561184561003561989

    Dmm

    Lmm

    lmm

    Obs StaticLoaddaN

    Deflectionmm

    Maxangle

    degrees

    StaticLoaddaN

    Deflectionmm

    Maxangle

    degrees

    Reference

    RADIAL TORSION CONICALAXIAL

    The references kept in stock are written in bold.

    17

  • LAMINATED BUSHES

    DIMENSIONS

    OPERATING CHARACTERISTICS

    dmm

    12

    14

    14

    16

    20

    34

    35

    40

    40

    38

    -

    -

    55

    -

    -

    48

    58.3

    27.4

    46

    60

    30

    43

    16.3

    32

    59

    -

    -

    17

    -

    -

    2

    2

    1

    2

    2

    560033

    561040

    531427

    560062

    579071

    Dmm

    Amm

    Lmm

    lmm

    l1mm fig. Reference

    Reference

    MaximumRadial Load

    Torsion

    531427*

    560062

    560033

    561040

    579071

    StaticdaN

    400

    900

    750

    850

    10500

    -

    -

    -

    -

    15000

    130

    40

    40

    50

    Axial StaticLoaddaN

    20

    15

    20

    20

    6

    80

    20

    10

    50

    54

    Approx torqueN.m

    Max AngleDynamic

    daN

    * The axial load is measured on the side of the lateral stop.

    18

    Fig. 1 Fig. 2

    l1

    l

    Dd

    l

    L

    DdA

    L

  • VOID BUSHES

    dmm

    8.5

    8.5

    12

    12

    12

    12.2

    12.2

    34

    40

    40

    43

    48.8

    30

    30

    -

    -

    -

    60

    57

    41

    41

    44.8

    44.8

    60

    41

    74.7

    34.1

    34.1

    36

    36

    40

    26.5

    62

    25.2

    25.2

    -

    -

    -

    32.5

    67.2

    26.5

    26.5

    2

    2

    2

    1

    1

    1

    1

    560218

    560217

    560065

    531413

    531376

    531363

    531431

    Dmm

    Amm

    Lmm

    lmm

    l1mm fig. Reference

    19

    section XX

    section XX

    Fig. 1

    Fig. 2

    l1

    l

    X

    L

    Dd

    X

    A

    l

    X

    X

    L

    d D

    DIMENSIONS

  • 20

    FLANGED BUSHES

    FLANBLOC

    dmm

    Dmm

    Amm

    Lmm

    lmm

    l1mm

    l2mm

    Dyna-micaxialload

    Maxangle

    Torsion

    Approxtorque

    N.m

    Fig. ReferenceStaticdaN

    Maximum radialload

    Dyna-micdaN

    SPECIAL S.C.

    dmm

    16

    Dmm

    32

    32

    36

    Amm

    47

    47

    46

    Lmm

    62

    89

    41

    lmm

    48

    48

    28.8

    l1mm

    56.5

    83.5

    34.7

    l2mm

    Dyna-micaxialload

    Maxangle

    Torsion

    Approxtorque

    N.m

    Fig. Reference

    9.5

    250

    250

    60

    StaticdaN

    Maximum radialload

    Dyna-micdaN

    Ove

    rloa

    dco

    effic

    ient

    : 3

    430

    430

    56

    30

    30

    30

    45

    45

    90

    2

    2

    1

    866016

    866012

    867001

    12

    16

    -

    32

    40

    40

    43

    50

    51

    50

    50

    83

    34

    32

    52

    40

    40

    76

    3

    1

    50

    150

    200 Ove

    rloa

    dco

    effic

    ient

    : 3

    160

    120

    -

    35

    20

    20

    16

    -

    3

    2

    3

    531300

    531411

    531417

    Fig. 1 Fig. 2 Fig.3

    l1l2

    lDd

    L

    A

    l1

    l

    Dd

    L

    A A

    l1

    l

    L

    Dd

    l2

  • 22

    -

    1

    1

    566050

    566051

    568256

    568247

    568248

    ReferenceFig.

    21

    PIVOT BUSHES

    FLUIDBLOC AND TOURIFLEX

    These are high precision bushes; they are made of injected polyurethane and can resist oil, water,ozone, etc.These PIVOTING bushes are characterised by their very low torsional resistance (0.1 to 0.2 N.m).They can ensure a complete rotation (360), and have no requirements for maintenance becausethey have a permanent lubricant.They don't need a high precision housing, and the load to remove the bushes is between 1500 and1800 daN.There are many applications, such as :Leaf spring bushes for vehicles not exceeding 5 tons.

    dmm

    16

    16

    SQUARE

    AXIS

    27

    36

    Dmm

    36

    45

    140

    70

    88

    lmm

    60

    60

    214

    60

    70

    Lmm

    70

    70

    304

    76

    86

    Maximum radialload

    static daN

    900

    1100

    7000

    1000

    1000

    Fig. 1 Fig. 2

    Dd

    L

    l

    Dd

    L

    l

  • 22

    SPHERICAL BUSHES

    SPHERIFLEX

    FLUIDBLOC

    dmm

    3524352626

    40(a)36

    axis(c)axis(c)axis(c)

    36.5axis(c)axis(c)axis(c)axis(c)

    4444

    Dmm

    626467808080858585889090909090

    100100.2

    Lmm

    3658

    35(b)72(b)78(b)49(b)

    8090

    1007580908090

    100114116

    Amm

    170180144

    170172170180

    lmm

    36303656565666.5627166686877777787.572.5

    MaxdaN

    Radial load Torsion Conical

    1000800

    100038003800380038003800380038004400400044004400440070007000

    StiffnessdaN/mm

    16002200160055005500550030003000300030005380500053805380538060006000

    Maxdegrees

    1212121010101212121212121212121212

    StiffnessN.m

    radian

    10022

    100220220220215215215215230215230230230150150

    Maxdegrees

    810

    888866668

    1088888

    StiffnessN.m

    radian

    680220680

    19001900190016501650165016503050280030503050305020002000

    Fig.

    11111112221222211

    Reference

    563075563489563559563353563343563354563317563344563425563253

    563316/13563345563300563555563426563571563605

    (a) : The internal diameter is shouldered (b) Length L not centered (c) Axis (square or flat ends)

    dmm

    24

    Dmm

    64

    Lmm

    58

    lmm

    36

    Radial staticload daN

    850

    Axial staticload daN

    100

    Slidingtorque

    N.m

    10

    Reference

    568184

    Fig. 1 Fig. 2

    l

    D d

    L

    A

    d

    L

    l

    D

    d

    L

    l

    D

  • 23

    SPECIAL BUSHES

    Reference Fig. Amm

    Bmm

    Cmm

    Dmm

    Emm

    Radial stiffnessKN/mm

    Axial stiffnessKN/mm

    563468562908562912563533563550563443531293531367531330563352

    2

    1

    1

    2

    2

    2

    3

    3

    3

    1

    180

    140

    140

    185

    185

    132

    110

    110

    122

    122

    200

    254

    273

    190

    190

    154

    55

    95

    72

    254

    140

    160

    145

    150

    150

    136

    42

    33

    54

    120

    68 cone

    50 x 56

    63

    70 cone

    68

    70

    50

    52

    70

    50

    -

    -

    -

    -

    -

    -

    86

    150

    162

    -

    85

    85

    20

    57.5

    57.5

    140

    17

    10

    40

    4

    10

    17

    5

    16.75

    16.75

    5

    8

    50

    30

    5

    563264

    862624

    Radial load max. : 100 kN

    Radial load max. : 70 kNRadial load/Displacement

    1 2 3 4 5 mm

    kN

    25

    20

    15

    10

    5

    0

    561958130

    160

    115

    140

    148

    270 100conical

    172

    100

    192

    Fig. 1

    C

    B

    A

    D

    C

    B

    E

    Fig. 3

    B

    C

    D

    A

    Fig. 2

    D

    A

  • OTHER PAULSTRA DOCUMENTATIONAvailable upon request

    AEROSPACEAND DEFENCECATALOG

    FLEXIBLEMOUNTINGSCATALOG

    FLEXIBLECOUPLINGSCATALOG

    METALMOUNTINGSCATALOG

    MARINE / NAVYLEAFLET

    INDUSTRIALVEHICLESLEAFLET

    RAILWAYCATALOG

    OFFSHORECATALOG

    POWERGENERATIONLEAFLET

    ContentsGeneralThe operation of a flexible bushesStatic characteristicsDynamic charcacteristics

    Principal types of flexible bushesSimple - FlangedLaminated - Void - PivotSpherical and other bushes

    Outer sleeve and centre axisSelection of a flexible bushInspection of flexible bushesDimensional controlControl of stiffness - Control of bonding

    Data sheetsSimple bushesLaminated bushesVoid bushesFlanged bushesPivot bushesSpherical bushesSpecial bushes

    Other Documentations