EN 2755:2009

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.KQLþQDVSHFLILNDFLMDLuft- und Raumfahrt - Gelenklager, aus korrosionsbeständigem Stahl mit selbstschmierender Beschichtung - Reihe hohe Belastungen bei Raumtemperatur - Technische LieferbedingungenSérie aérospatiale - Rotules, en acier résistant à la corrosion à garniture autolubrifiante - Série à charge élevée à température ambiante - Spécification techniqueAerospace series - Bearings, spherical plain in corrosion resisting steel with self-lubricating liner - Elevated load at ambient temperature - Technical specification49.035Sestavni deli za letalsko in vesoljsko gradnjoComponents for aerospace constructionICS:Ta slovenski standard je istoveten z:EN 2755:2009SIST EN 2755:2009en01-november-2009SIST EN 2755:2009SLOVENSKI
STANDARD
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 2755July 2009ICS 49.035 English VersionAerospace series - Bearings, spherical plain in corrosionresisting steel with self-lubricating liner - Elevated load atambient temperature - Technical specificationSérie aérospatiale - Rotules en acier résistant à lacorrosion à garniture autolubrifiante - Série à charge élevéeà température ambiante - Spécification techniqueLuft- und Raumfahrt - Gelenklager, auskorrosionsbeständigem Stahl mit selbstschmierenderBeschichtung - Reihe hohe Belastungen beiRaumtemperatur - Technische LieferbedingungenThis European Standard was approved by CEN on 16 April 2009.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre:
Avenue Marnix 17,
B-1000 Brussels© 2009 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 2755:2009: ESIST EN 2755:2009

Verification of permissible and ultimate static loads.24 A.1 Permissible radial static load (Cs) .24 A.1.1 Principle .24 A.1.2 Method .24 A.2 Ultimate radial static load .24 A.2.1 Principle .24 A.2.2 Method .24 A.3 Permissible axial static load (Ca) .25 A.3.1 Principle .25 A.3.2 Method .25 A.4 Ultimate axial static load .25 A.4.1 General .25 A.4.2 Principle .25 A.4.3 Method .25 Annex B (normative)
Verification of dynamic radial load (C25) .28 B.1 Principle .28 B.2 Method .28 B.2.1 Testing at ambient temperature .28 B.2.2 Testing at low temperature .28 B.2.3 Testing at elevated temperature.28 B.2.4 Test at ambient temperature after immersion .29 Annex C (normative)
Fluids – Essential characteristics .30 C.1 Fuel for turbine aero engine .30 C.2 Fluids for de-icing circuit .30 C.3 Hydraulic fluids .30 C.3.1 Mineral fluid for hydraulic transmission .30 C.3.2 Phosphate of ester hydraulic fluid .30 C.4 De-icing and anti-icing fluids .30 Annex D (normative)
Measurement of the peel strength of the liner .31 D.1 Principle .31 D.2 Method .31 Annex E (normative)
Simplified qualification procedure .33 E.1 Rules for application .33 E.1.1 General .33 SIST EN 2755:2009

1 In preparation at the date of publication of this standard. SIST EN 2755:2009

2 Published as ASD Technical Report at the date of publication of this standard. SIST EN 2755:2009

See Table 1. SIST EN 2755:2009

Material In accordance with the product standard or design documentation. Chemical analysis or certificate of compliance according to EN 10204, issued by semi-finished product manufacturer. X X X X 4.2
Dimensions, tolerances In accordance with the product standard or design documentation. Suitable measuring instruments. X X Measurement of bore and outer diameter:
 Rings with a width of ≤ 10 mm: in the centre plane;  Rings with a width of > 10 mm: in two planes parallel to the outer faces and at a distance of these faces of twice the maximum value of the ring chamfer. The minimum and maximum diameters shall be determined in each measuring plane.
Measurement of ring width:
 The width of each ring (distance between the two faces) shall be verified at a minimum of four points.
4.3
Masses In accordance with the product standard or design documentation. Suitable methods. X
4.4
Marking In accordance with the product standard or design documentation. It shall be legible and shall not adversely affect the material or the functioning of the bearing. Visual examination. X X 4.5
Surface appearance The bearings shall be free of surface discontinuities liable to have an adverse effect on their characteristics and endurance.
The liner shall not contain contaminant products and shall not show broken or voided areas.
Lubrication shall not be permitted.
4.5.1
Assembled bearings
Visual inspection using suitable methods. X X 4.5.2
Unassembled rings
Magnetic or dye penetrant inspection. X X continued SIST EN 2755:2009

Hardness In accordance with the product standard or design documentation. Suitable processes and measuring instruments. X X 4.7
Surface roughness In accordance with the product standard or design documentation. Suitable processes and measuring instruments. X X 4.8
Surface treatment In accordance with the product standard or design documentation. Visual inspection. X X As per surface treatment standard.
4.9
Behaviour in rotation and tilt Bearings shall be able to move freely within the angular limits specified in the product standards or design documentation. Manual inspection. X X 4.10
Starting torque without load
4.10.1
At ambient temperature In accordance with the product standard or design documentation. Suitable processes and measuring instruments: X X  measurement of the starting torque shall be preceded by some rotations and a few turning movements by hand;  measure the torque, apply gradually to the inner ring, in both directions, with the outer ring held stationary. Read off the maximum value required to start up the inner ring.
4.10.2
At low temperature Starting torque ≤ twice those listed in the product standard or design documentation. Subject the bearing, during 4 h at the minimum temperature ± 5 °C. X
Immediately after, measure the torque following 4.10.1.
4.10.3
After limit temperatures In accordance with Tables 2 and 3. Subject the bearing, during 1 h at the minimum temperature ± 5 °C, then 1 h at the maximum temperature ± 2 °C. X
Repeat successively × 10 this test.
4 h after these tests, measure the torque, at ambient temperature, following 4.10.1.
continued SIST EN 2755:2009
Conformity of spherical surface For fabric type liners no difference between measurements obtained on spherical surfaces shall exceed 0,08 mm. Clad the bearing in plastic material identical to that used for metallurgical mounts. X
Section the bearing on a diameter and normal to the race side face.
Grind and polish the exposed surface.
Measure distance 't', checked at a minimum of five points uniformly spaced around the spherical diameter with the aid of, for example, an optical dial indicator (see Figure 1).
For moulded liners:  the maximum liner thickness shall occur between C/10 position;  the minimum liner thickness shall be 0,20 mm. Clad the bearing in plastic material identical to that used for metallurgical mounts. X
Section the bearing on a diameter and normal to the race side face.
Grind and polish the exposed surface.
Measure distance 't', checked at a minimum of five points uniformly spaced around the spherical diameter with the aid of, for example, an optical dial indicator (see Figure 1). The points shall include the midpoint and the C/10 positions.
4.12
Permissible static loads:  radial: Cs  axial: Ca In accordance with the product standard or design documentation. See Annex A. X
No maximum total deflection greater than those listed in Tables 4 and 5 under permissible static loads (Cs).
After removing the loads, no permanent deformations greater than those listed in Tables 4 and 5.
4.13
Ultimate static loads:  radial  axial After removing the loads, there shall be no cracks, no push out of the inner ring or deterioration of the bearing. See Annex A.
continued SIST EN 2755:2009
Dynamic radial loads C25:  at ambient temperature  at low temperature  at elevated temperature In accordance with the product standard or design documentation. See Annex B. X
After the removal of the loads:
 no metal-to-metal contact between inner and outer ring;
 the liner wear shall not exceed the values listed in Table 6;
 the peel strength and the bond integrity shall conform with 4.16 and 4.17.
At the end of the test, the starting torque under radial load shall be measured and shall conform with values listed in Tables 7 and 8. Suitable processes and measuring instruments.
4.15
Liner compatibility with the fluids At the end of this test, see 4.14.Check one bearing per fluid: X
 put the inner ring perpendicularly to the outer ring;
 the bearing shall be immersed for 24 h in the fluids stated in Annex C at the following temperatures:
 (45 ± 3) °C for those defined in C.1 and C.2;
 (70 ± 3) °C for those defined in C.3;
 ambient temperature for those defined in C.4.
Within ½ h after this test, proceed to the test defined in B.2.4.
4.16
Peel strength of the liner These requirements and this test apply only in the case where the manufacturer has established whether the liner is peelable or non peelable. See Annex D. For acceptance, this test shall be carried out immediately after assembling and curing. X X
It shall present a mean peeling resistance > 0,35 N for each millimetres of the outer ring reduced by 2 mm to eliminate the effects of edges and chamfers.
Mean peeling resistance is determined using at least 75 % of the values on the recording curve.
continued SIST EN 2755:2009
A b
4.17
Bond integrity of the liner For peelable liner, the liner: After the peel strength test, evaluate the location and size of any voids. X X
 shall not contain any contamination substances;
 shall adhere tightly to the outer ring over at least 90 % of the contact area. No void shall be allowed which cannot be described within a circle of diameter equal to:
 25 % of outer ring width;
 6 mm
whichever is smaller.
For non-peelable liners, a sectioned bearing shall be examined for bond integrity. Destructively examine the liner by chipping, scraping, abrasion, or other appropriate means to determine the bond integrity. X X
The liner
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