1、AECMA Technical Report Rapport Technique AECMA AECMA Fach beric ht Edition approved for publication Extra copies can be supplied by B.N.A.E. Technopolis 54 - 199, rue Jean-Jacques Rousseau 2000-02-29 92138 ISSY - LES - MOULINEAUX CEDEX - FRANCE 0 aecrna 201 TR 4271 Edition I 02-00 _ _ PUBLISHED BY T
2、HE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES (AECMA) Guliedelle 94 - 8-1200 BRUXELLES - Tel. (+32) 2 775 81 10 - Fax. (+32) 2 775 81 11 ICs: 49.080 Descriptors: Hydraulic fluid power, fluid circuits, hydraulic component, sealing joint, O-ring, dimension, designation ENGLISH VERSION Aerospace seri
3、es O-rings grooves Design criteria for O-ring grooves Basic calculations Srie arospatiale Gorges pour joints toriques Critres de conception Calculs de base Luft- und Raumfahrt Nuten fr O-Ringe Konstru ktionsrnerkmale Grundlegende Berechnungen This Technical Report was drawn up by the Technical Commi
4、ttee C 8 of the AECMA Standardization Committee. The reason which led to the publication of the documenf as a Technical Report is explained in the foreword. Foreword The main task of AECMA Technical Committees is to prepare EN standards. In exceptional circumstances, however, the publication of a Te
5、chnical Report of one of the following types may be proposed: - type 1, the subject is still under technical development requiring wider exposure; - type 2, a Technical Committee has collected data of a different kind from that which is normally published as a European Standard. Technical Committee
6、C 8, Engines, decided to publish this document in the form of a Technical Report of type 2, because contained information consists of values for guidance and must in no way be considered as a technical requirement. Design solution of a O-ring remains the sole responsibility of the designer, Contents
7、 O 1 2 3 4 4.1 4.2 5 5.1 5.1.1 5.1.2 5.2 5.2. I 5.2.2 6 6.1 6.2 6.3 6.4 6.5 6.6 6.6.1 6.6.2 6.7 6.7.1 6.7.2 7 7.1 7.2 7.3 7.4 8 8.1 8.1.2 8.2 8.3 8.4 8.5 8.1.1 8.1.3 Introduction . . . . . . . . , , . . . . . , . . . . . , , . , , . . . . . . . . . . . , , , . . . . , . . . . . . . . . . , . , . . .
8、 . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . , . . . . . . , , . , . , . , . , . , . . . . . , . . . , . . , . . . . , , . , , . , . . . . , . . . . , . . . . . , . . , , , , . . , , . . . . . , . , . . , , . , . . . . . . . . . . . . . . . . . . . . . . . , , , , Symbols . Gener
9、als Rubber families concerned . Permissible pressures Radial sealing Rod housings Bore housings . Axial sealing Face seals for internal pressure source Face seals for external pressure source . Factors influencing the quality of sealing. ._It.5MPa 6.1 Surface roughness Surface roughness value and ch
10、aracter of the component in contact with the O-ring are dependent on the application and its life requirements, and where doubt exists should be subject to agreement between manufacturer and user. See table 1. with pressure variation s5MPa I 5MPa Table 1 Dimensions in micrometres continuous pressure
11、 Surface with pressure variation Groove d2 2 min. Side surfaces Inside diameter 1,80 2,65 3,55 5,30 7,OO 1,1 1,5 188 2,7 3,6 Homologous surface Roughness s 5 MPa 12,5 5MPa r5MPa 5MPa i-+ 6.2 Corner and edge radii See table 2. Table 2 Dimensions in millimetres 6.3 I 613 6,3 l+l 0,2 to 0,4 0,l to 0,3
12、0,4 to 0,8 0,8 to 1,2 Lead-in chamfers Use a chamfer angle of 15“ to 20“ to prevent damage to the O-ring on assembly. Provide for the length of lead-in chamfer Z as shown in table 3. It is imperative that chamfer edges be rounded. 6.4 Groove run-out tolerances - Groove diameter d3 or ds I 50; maximu
13、m run-out tolerance Y = 0,025 - Groove diameter d3 or 6 50; maximum run-out tolerance Y = 0,05 STD-AECMA TR Li271i-ENGL 2C100 II 10123LL 0017920 590 Page 9 TR 4271 1 02-00 Bore diameter, rod mounted d4 O-ring groove diameter, rod mounted d3 d4 Total tolerances + d3 6.5 Housing diameter tolerances Th
14、e following tolerances as shown in table 4 are recommended. 1,80 2,65 335 5,30 7,OO + 0,06 + 0,07 + 0,08 + 0,09 +O,ll O O O O O O O O O O - 0,04 - 0,05 - 0,06 - 0,07 - 0,09 0,l o 0,12 0.14 0,16 0,20 Table 4 Dimensions in millimetres Rod outside diameter, bore mounted O-ring groove diameter, bore mou
15、nted Total tolerances Housing diameter I d2 O O O O O - 0,04 - 0,055 - 0,06 - 0,07 - 0,09 + 0,06 + 0,07 + 0,08 + 0,09 + 0,ll O O O O O d5 d6 d5 + 0,lO 0,12 0,14 0,16 0,20 d6 Bore diameter, bore mounted O-ring groove outside diameter, internal pressure I dg I Rod outside diameter, rod mounted dl o H8
16、 HI 1 4 t7 O-ring groove outside diameter, external pressure I I hl 1 Important: in the event of high pressure together with pulsatory phenomena, it is imperative that the clearance between the rod and bore be reduced. A H7 tolerance for bore and g6 for rod are recommended. This recommendation is al
17、l the more valid in that the seal section is small and the seal diameter is large. STD*AECMA TR 4271-ENGL 2000 E Lc1223LL 0017921 427 = Page 10 TR 4271 : 02-00 Application Static radial Static axial 6.6 Housing width and depth 6.6.1 Housing width (b) + 0,25 See table 5, with tolerance o d2 i ,80 2,6
18、5 3,55 5,30 7,oa 2,40 3,60 4,80 7,10 9,20 2,60 3,80 5,OO 7,30 9,40 d2 6.6.2 See table 6. Housing depth (h or t) Radial sealing Axial sealing Bore housing I Rod housing Table 6 Dimensions in millimetres t f h a This value is to be used to calculate the housing diameter d3 or de. The minimum and maxim
19、um values were used to establish the O-ring squeeze values as specified in table IO. STD-AECMA TR LUL-ENGL won m I,OLZI,I, OOI, 33 m Page 11 TR 4271 02-00 O-ring inside diameter di mm 55 6.7 Stretch and compression O-ring 6.7.1 Radial sealing 6.7.1 .I Stretch See table 7. Stretch Yin % rnax. min. a
20、a Table 7 O-ring inside diameter di mrn 55 5 and I 10 10 and 5 and I 10 I 8 l 400 IO and 400 I _ a The stretch values are to be individually calculated for each d1 as the clearance between dl max. and di min. is important taking into account the O-ring casting tolerances. It is advised to be as as n
21、ear as possible to the values applying to the diameter range of di z 5 and 5 10 while imperatively keeping a 2 Oh minimum stretch. 6.7.1.2 Compression See table 8. Table 8 STD-AECMA TR 4273-ENGL 2000 1022311 0037723 2TT I Page 12 O-ring inside diameter dl a mm I100 TR-427 I : 02-00 Internal pressure
22、 External pressure Max. K % compression on d7 Max. Y YO stretch on ds 4 6.7.2 Axial sealing See table 9. Table 9 200 2 3 I Yo or a maximum of 0,8 mm 100 and I 200 a in this table but less than 5 %. For the 1 I 5 mm diameters, the stretch values (external pressure) may be greater than the values 7 Me
23、thod of calculating housing dimensions 7.1 d3 rnax. = d4 min. - 2 t nom. Tolerances as per table 4 Depth t nom. as table 6 Width b as table 5 Radial application - Piston housing 7.2 ds min. = d5 max. + 2 t nom. Tolerances as per table 4 Depth f nom. as table 6 Width b as table 5 Radial application -
24、 Rod housing 7.3 d7 nom. = di nom. + 2 d2 nom. Tolerances as per table 4 Axial application - Internal pressure 7.4 d8 nom. = dl nom. Tolerances as per table 4 Axial application - External pressure 8 Design criteria Housing dimensions are derived from consideration of such design criteria as: - O-rin
25、g stretch or compression; - cross-section reduction; - O-ring squeeze; - O-ring swell. This clause amplifies these criteria and indicates the extreme values within which they are applied. Page 13 TR 4271 02-00 8.1 O-ring stretch or compression 8.1 .I Rod housing Only stretch of an O-ring inside diam
26、eter dl has been permitted. A clearance between d3 and di is not permitted, a minimum stretch is required (see table 7). Thus smallest permitted d3 = di max. (1 + Y1100 min.) largest permitted d, - d, min. dl min. max. Y % = x 100 Or largest permitted d3 = di min. (1 + Y1100 max.) Thus smallest perm
27、itted d3 = dl max. (1 + Y1100 min.) Largest permitted d3 = dl min. (1 + Y11 O0 max.) d4 max. at the upper limit or range d4 min. = d3 max. + 2 t min. with d3 max. = dl min. (I + Y/lOO max.) and t min. as table 6 I I d4 min. = di min. (1 + Y1100 max.) + 2 t min. 1 d4 table = d4 min. + tolerance (see
28、table 4) (1) 1 d4 min. at the lower limit or range d4 max. = d3 min. + 2 t max. with d3 min. = d, max. (1 + Y/lOO min.) and t max. as table 6 d4 max. = dl max. (1 + Y/lOO min.) + 2 t max. d4 tabulated = 4 max. -tolerance (see table 4) (2) Since nominal size in the case of cylinder diameters (d4) is
29、the minimum, range of nominal cylinders over which any seal may be used is from formula (1) to formula (2). The bore diameter (diameter d4) for which the O-ring could be used will be ranged between the formula (I) results and those of the formula (2). TR-4271: 02-00 EXAMPLE 1: Suppose that there is
30、an O-ring of code A0400, used as an O-ring of piston type dl max. = 40,33 mm d, min. = 39,67 mm d2 max. = 1,88 mm d2 min. = 1,72 mm 2tmax. = 2,92 mm 2 tmin. = 2,72 mm Y% max. = 6 Y% min. = 2 d4 min. = d3 max. + 2 t min. d3 max. = 39,67 (I + 0,06) = 42,05 d4 min. = 42,05 + 2,72 = 44,77 d4 table = d4
31、min. + tolerance (table 4) = 44,77 + o = 44,77 d4 max. = d3 min. + 2 t max. d3 min. = 40,33 (1 + 0,02) =41,137 d4 max. = 41,137 + 2,92 = 44,057 d4 table = d4 max. - tolerance (table 4) = 44,057 - 0,06 = 43,997 Range of use of diameter d4 nominal values by the O-ring of code A0400 I d4 nom. = 43,997
32、to 44,77 I The choice of a d4 nominal in the above given range implies to redefine d3 in accordance with the equation: d3 nom. = d4 nom. - 2 t nom. The tolerance of d3 is given in table 4. 8.1.2 Bore housing Only compression of an O-ring outside diameter Dl (d1 + 2 d2) has been permitted. A clearanc
33、e between d6 and Dl is not permitted, a minimum compression (K %) is required (see table 8). Thus largest permitted d6 = (dl min. + 2 d2 min.) (1 - WIOO min.) Maximum compression = K Oh (specified in table 8) d, max. + 2 d, max. - smallest permitted de d, max. + 2 d, max. max. K YO = x 100 Or smalle
34、st permitted de = (dl max. + 2 d2 max.) (1 - KI100 max.) Largest permitted d6 = (dr min. + 2 d2 min.) (I - Ki100 min.) Smallest permitted de = (d, rnax. + 2 d2 max. (1 - W100 max.) 5 max. at the upper limit or range d5 min. = d6 max. - 2 t max. with d6 max. = (d, min. + 2 d2 min.) (1 - KI100 min.) a
35、nd t max. as table 6 d5 min. = (dl min. + 2 d2 min.) (I - NI00 min.) - 2 f max. d5 tabulated = d5 min. + tolerance (see table 4) (3) 5 min. at the lower limit or range d5 max. = d6 min. - 2 t min. with d6 min. = (d, max. + 2 d2 max.) (1 - WIOO max.) and f min. as table 6 d5 max. = (d, max. + 2 d2 ma
36、x.) (1 - N100 max.) - 2 t min. d5 tabulated = d5 max. - tolerance (see table 4). (4) .e. range of rod diameters (s) over which any O-ring may be used is given by formula (3) to formula (4). These are nominal sizes. STD-AECMA TR 4271-ENGL 2000 LOI2333 0037927 745 W Page 16 TR-4271: 02-00 EXAMPLE 2: S
37、uppose that there is an O-ring of code A0400, used as an O-ring of rod type dl max. = 40,33 mm dl min. = 39,67 mm d2 max. = 1,88 mm d2 min. = 1,72 mm 2tmax. = 3,02 mm 2 tmin. = 2,82 mm Y%max. = 6 Y % min. = 2 d5 min. = d6 max. - 2 t max. d6 max. = (39,67 + (2 x I ,72) (1 - 0,02) = 42,248 d5 min. = 4
38、2,248 - 3,02 = 39,228 d5 table = 39,228 + 0,04 = 39,268 = ds min. + tolerance = (table 4) d5 max. = d6 min. - 2 t min. d6 min. = (40,33 + (2 x 1,88) (1 - 0,06) = 41,445 d5 max. = 41,445 - 2,82 = 38,625 d5 table = d5 max. - tolerance (table 4) = 38,625 + O = 38,625 Range of use of diameter d5 nominal
39、 values by the O-ring of code A0400 ds nom. = 38,625 to 39,268 The choice of d5 nominal in the above given range implies to redefine de in accordance with the equation: d6 nom. = ds nom. + 2 t nom. The tolerance of d6 is given in table 4. Page 17 STD-AECMA TR q271-ENGL 2000 m LO12311 0037928 881 m T
40、R 4271 02-00 8.1.3 Axial housing 8.1.3.1 Internal pressure The K % compression of the O-ring outer nominal diameter (see table 9). d7 max. at the upper range or limit d7 max. = dl nom. + 2 d2 nom. + tot. HI1 d, tabulated = d7 max. - tol. HI1 d7 tabulated = d, nom. + 2 d2 nom. The maximum compression
41、 K % shall be associated with the nominal diameter plus the tolerance on this diameter. d7 min. at the lower range or limit d7 min. = d7 max. (1 - KlIOO) establishes the absolute d7 minimum diameter d7 tabulated = d7 min. 8.1.3.2 External pressure The Y % stretch of the O-ring inside nominal diamete
42、r (see table 9). da max. at the upper range or limit da max. = dl nom. (1 + Y/lOO) = da tabulated de min. at the lower range or limit da min. = dl nom. da tabulated = d, nom. + tol. hl 1 8.2 Cross-section reduction Where O-rings are stretched, there is a reduction in cross-section. This can be calcu
43、lated as follows: d, max. - d, min. 10 d, min. Maximum reduction This formula exaggerates the reduction in cross-section slightly for any stretch below 10 %. Most designs can be approximated by assuming a cross-section reduction of 3 % for every 4 % of stretch. A possible easier to understand expres
44、sion is: d, min. (7 d, min. - 3 d3 max.) 4 d, min. Minimum section diameter (d;) of stretched ring = STD.AECMA TR Li27L-ENGL 2000 m 10L23LL 0037929 7LB m Page 18 d2 mm TR-427 1 : 02-00 Radial sealing Axial sealing Rod housing Bore housing max. 1 min. max. I min. max. I min. 8.3 O-ring squeeze (e) Th
45、e table 10 indicates the minimum and maximum values of squeeze in % calculated with the housing depths (fand h) specified in table 6. These values include the variations consecutive to the stretch or the compression and the component tolerances while ensuring a good sealing of the normal conditions
46、in use. 2,65 3,55 25,20 14,50 22,30 11,50 28,lO 19,OO 26,30 14,20 23,30 11,OO 24,70 17,50 I 1,80 I 27,70 1 15,lO I 25,OO I 12,OO 1 31,90 I 20,OO I 5,30 7,OO I I 23,80 13,50 20,80 10,50 21,90 16,OO 21,40 13,lO 18,50 10,OO 20,OO 1500 NOTE Radial housing: The squeeze values dont take into account stric
47、tion. e max. = (d2 max. - t min.) / d2 max. e min. = (d2 min. - t max.) i d2 min. Axial housing: e max. = (d2 max. - h min.) / d2 max. e min. = (d2 min. - h max.) I d2 min. 8.4 O-ring swell Since O-ring materials may absorb some amount of fluid when subjected to contact with the fluid, the compatibi
48、lity will vary with different fluids. The volume of the O-ring housing should be capable of absorbing the O-ring swell from the fluid and the O-ring expansion because of increase temperature. Therefore volumetric swell of 15 % has been applied to the calculations to derive the housing width dimensio
49、n “6“. When considering the use of O-ring materials that have in excess of 15 % swell, an appropriate allowance shall be made in the housing width. STD-AECMA TR 4273-ENGL 2000 = 1032331 0037930 43T Page 19 TR 4271 : 02-00 8.5 Housing widths Let Vh be the minimum volume of the housing and V, be the maximum volume of the O-ring. Vox 1,15=Vh V, = 2,4674 (dl max. + d2 max.) (d2 max.) = maximum O-ring volume V, = approximate housing volume lost by housing corner radii housing sealing Vr4 = approximate housing volume lost
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