1、UDC 629.7.03 : 621.4-238 M 32 : JUIY, 1969 . BRITISH STANDARD : AEROSPACE SERIES SPECIFICATION FOR DIMENSIONS OF AIRCRAFT ACCESSORY DRIVES AND. MOUNTING PADS FOREWORD . . The requirements for the accessory drives and mounting pads quoted in this British Standard are based upon the Society of British
2、 Aerospace Companies standard RS.623, and have also been accepted as the basis of a Recommendation of the Inter- national Organization for Standardization, R . . . . , Aircraft accessory drives and mounting pads* factors and tables, suitably rounded to the conversion rules specified in BS 2856, Prec
3、ise conversion of inch and metric sizes on engineering NOTE. The values in inch units are to be regarded as the standard. The values in metric units are equivalents based upon BS 350, Conversion drawings. This makes reference to the following British Standards: i Part 3. Geometrical tolerancing usin
4、g IS0 tolerance symbols“. i Part A7. Determination of hardness. . _“ BS 308. Engineering drawing practice. -1. BS 903. Methods of testing vulcanized rubber. 6$:-2 c:;q,. _ . I r.r(r. Is the metric dimensions given in the tables are exact manufacturing equivalents. 3. RJ3QUDREMENTS FOR ASSEh3BLY SEQU
5、ENCE 3.1 The enginelgearbox pads and accessory flanges are dimensioned so that the locating pin (or transfer tube) is engaged in its mating hole before the interference on the spigot sealing rings prevents rotation of the accessory casing. 3.2 In fixing the protrusion of the drive shaft, considerati
6、on shall be given to engaging the spline before the locating pin (or transfer tube) is engaged, in order to ease assembly. 3.3 For neavy accessories, the design shall be arranged to avoid the possibility of the fitter allowing the weight of the unit to hang on the splines rather than thespigot. This
7、 can usually be arranged by keeping the amount of spline engagement to a minimum before the spigot is engaged. -. I A -. . 5. TRANSFER TUBE? AND LOCATING AND/OR TORQUE - 5.1 Any transfer tubes or locating pins shall be retained in the engine/gearbox mounting pad. 5.2 If more than one transfer tube o
8、r locating pin isto be . fitted, the angular positions shall be agreed .between the . engine/gearbox manufacturer and the accessory: manu- facturer. -. 5.3 The inethod ofretention and the-suppiy oftubesor. - - REACIWGPWS . - _ - . 1 t 18.1 To avoid machining the taper flange on large casings, . :or
9、when such machining is impracticable, it is permissible to introduce an adaptor having a taper flange at one end - /and a bolted flange at the other for attachment to the enginelgearbox casing. r-it3.2 The design and supply of adaptor flanges shall be the J lresponsibility of the engine/gearbox manu
10、facturer. 4 - .“ 8. ADAPTORS .! ,_ pins shall be the engine/gearbox manufacturers responsi- i i . -j 5.4 The provision for accepting the torque reaction of the . accessory shall be as agreed between the enginelgearbox .! manufacturer and the accessory manufacturer. .: . . . . .:G, :-I 9. SELECIlON A
11、M) DESIGN OF SPLINT DRIVES . bility; . . .T. ,9.1 Drive shaft sizes shall be selected from the list in ;Table 6. The size, length of engagement and other details, . jshall be subject to agreement between engine/gearbox manu- :;facturer and accessory manufacturer. Fig. 6 gives parti- . -3, . -I ion t
12、he appropriate drawings. .“ . . . M 32 : July, 1969 9.3 The position and alignment of the accessory drive shall be of such accuracy as to meet the following requirements: L i s I I I that - 7 1 XL 61 where x = minimum effective circumferential clearance in the splines (backlash), L length between sp
13、lines (this should be as large as possible), 1 = length of spline drive (this should be as small as possible), 6 c= out of alignment of splines between drive and accessory due to manufactur- ing tolerances. 10. LUBRICATION OF SPLINES The arrangements for lubricating the splined shaft shall be agreed
14、 between the enginelgearbox manufacturer and the accessory manufacturer, whilst the responsibility shall rest with the former. An efficient seal shall be incorporated in the accessory to prevent ingress or egress of oil or other fluid. 11. SAFEGUARDING OF ENGINE OR GEARBOX It shall be the joint resp
15、onsibility of the enginelgearbox and accessory manufacturers to ensure that the failure of the accessory does not hazard the efficiency or safety of the enginelgearbox by, for example, vibration, overloading the drive, ingress of debris, or loss or contamination of engine oil. 12. IDENTIFICATION Thi
16、s British Standard number followed by the nominal spigot diameter, and the required spline drive shall be specified as follows: Mounting pad and drive to BS M 32 Spigot reference 412 Drive: 11 splines 24/48 pitch (-4583 pitch dia.) 3 M 32 t July, 1969 4 C O .- 4 P I. I M 32 t July, 1969 ! “ .- I m o
17、 * Pc, rnv) oco O0 d? B h S o a F N N - “ S N “ 4 a C = I .E i jE E t, a 1“ :c I hl Yi a ,- !.E i !I A 5 M 32 : July, 1969 r .I n C .- p. c O .e V m O .- - y. O .- m m # al n n O 8 6 M 32 : July, 1969 “E S 2 c Co “ c Lf, O _. . I l “ - ! i I I i “ I I I “ “ ! $8 COW (Dl+ O0 kLn “ “ I I S4 P? O0 . I
18、i l i f. /L I 2 m I. LnLo $5 22 n 9 N N .“ v) o, z N 3 B N Lo co O 9 rl rl Ln r S; v) CD 8 B 8 c? N 8 z O Lo M Cu CD 2 W d S a M rl E f _ .- e “ 8 o 8 Ln 8 9 N rl O 2 8 N 8 v I M 32,: July, 1969 *.COf-N (Dp?;qo 0o:rll-l “. ._ .- II i I I E, a !I E i 8 z 9 . O % 1 BSI M*32 b9 H Lb24bb9 O099320 9 m 1
19、I M 32 : July, 1969 A A 10 h W o 4 W c F M 32 : July, 1969 A A S O In z rl MM “Co 48 MM ! 11 M 32 : July, 1969 . 1 I M 32 t July, 1969 W M 3 _ N v) O 3 W I9 d W M m N O 3 v) N O M 3 8 M * cv 3 O v) g O 8 O W O M P W P S! 8 2 8 x v) m O r- rl 4 S: m * S: cp * N a 2 rl W z 4 W Cu 8 M N N 2 “ I I I I I
20、 d-N Ad - - -;+“ ;-“-I+-“ %S3 ?-P O0 8 M 5: M 13 M 32 t July, 1969 Circular spline thickness at pitch dia. / Major dia. Fig. 6. Diagram of involute splines to BS 3550 modlfied to provlde increased arcumferential clearance to BS 3550. NOTE 1. 30 pressure angle! fiuet root side fitting invplute spline
21、s NOTE 4. For all information not shown in Tables GA or GB refer (backlash). NOTE 2. The minor diameter has been reduced accordingly to NOTE 5. For hole particulars refer to S 3550 fillet root side fit, allow the splines to be produced with standard cutters. NOTE 3. Method of calculating clearance:
22、Effective minimum clearance = (min. effective space width) minus NOTE G. For flange particulars refer to Figs. 1 and 2, or 3 and 4. (mm. effective spline thickness). Theoretical memum clearance = (ma. actual space width) minus NOTE 7. For dimensions of modifications to spline shafts refer to (min. a
23、ctual sphe thlckness). Tables 6A or 6B. 14 M 32 : July, 1969 TABLE 6. DIMENSIONS OF SELECTED INVOLUTE SPLINES TABLE 6A. INCH DIMENSIONS I i I 14 j 48/96 i “ 17 i 48/96 14 : 40/80 “ O 17 i 40/80 15 32/64 “ 11 i 24/48 17 132164 “ 19 32/64 12 I20140 “ 23 i 32/64 17 124148 27 f 32/64 !- 17 /20/40 31 132
24、164 “ 19 120/40 22 j 20/40 “ 29 !24/4t 1 -i- - 1- “ ! “ t “ -.- E ! “ i I 1 Pitch Major dia. dia. , i 1“- j max. I min. l i 0.2917 i 0-3125 I 0.3095 0.3542 f 0.3750 I 0.3720 0.3500 I 0.3750 1 0.3720 0.4250 i 0.4500 10.4470 0.4688 0-5000 0.4970 0-4583 i 0.5000 i 0.4950 0.5313 0.5625 i 0.5595 0.5938 !
25、 0.6250 i 0.6220 06OoO ! 0.6500 ; 0.6450 0.7188 ! 0.7500 i 0-7470 -1 0.7083 1 0.7500 ! 0.7450 “ 0-8438 I 0.8750 1 0.8720 0.8500 i 0.9oOo 1 0.8950 I- I- “ “ 1- -. I- -. I-.“- I Minordla. i fromm 3550) , (modified i thickness (modi? 33.12 I 32.84 26 16/32 41-275 , 42.862 I 42.736 i 37-88 37.60 I 16/32
26、 1 “ !“- 30 I 16/32 ! 47.625 I 49.212 1 49.086 I 44.23 : 43.95 “ I _I_ -I- l -I_ i “ i :I “ i I- - -I- 32 i 16/32 50.8 i 52.388 I 52.260 I 47.36 t I I i 47.08 16 Modified increased Circular spline circumferential clearance with from BS 3550) splined hole to BS 3550 thickness (modified 0.922 1 0.892
27、0.889 I 0.859 0.076 0.203 1.146 I 1.113 1.107 I 1.074 0.102 0.244 1.892 i 1.862 1,854 I 1.824 0.102 0.241 -, I I M 32 : July, 1969 This British Standard, having been approved by the Aerospace Industry Standards Committee, was published under the authority of the Executive Board of the Institution on
28、 31 July, 1969. The Institution desires to call attention to the fact that this British Standard does not purport to include all the necessary provisions of a contract. British Standards are revised, when necessary, by the issue either of amendment slips or of revised editions. It is important that
29、users of British Standards should ascertain that they are in possession of the latest amendments or editions. The following BSI reference relates to the work on this standard: Committee reference ACE/14 Draft for comment 66/20435. SBN : 580 05750 X AMD 343 Amendmct Slip No. 1, pbfiislhed 24 Ocfber,
30、8969 to British Standard M 32 : 1969 Dimensions of aircraft accessory drives and mounting pads Foreword. Delete SP 148 and substitute “33. Table 1. Delete “In accordance with British Standard SP 148 and substitute *In accordance with British Standard M33. Figures 2 and 3. Delete 2000 and substitute
31、20-0, “O“ 10 , Tab!e 3. Delete *In accordance with British Standard SP . . . . and substitute *In accordance with British Standard M33. Figure 4. Transfer tube Z, delete R and substitute R5; delete 20_100 “O“ O“ and substitute 20“f0“ “o“ O Table 4E. Column headed in, delete 1 -03 and substitute 1 mo
32、o. U O BSI M*32 b9 E Lb24669 0099330 L m AMD 1221 Amendment Slip No.3, published 3 1 July, 1973 to British Standard M 32 : 1969 (Aerospace Series) Dimensions of aircraft accessory drives and mounting pads Corrections Clause 6.2 Delete the first sentence and substitute the following: It is recommended that a fail safe device be fitted to obviate the possibility of over-straining the bolt (or bolts) on assembly. Clause 7.2 Add the following sentence after the existing text: Care must be taken to ensure that bolts are not over-strained. See also 6.2.
