1、BRITISH STANDARD AUTOMOBILE SERIES BS AU 226:1988 ISO7648:1987 Specification for Nominal dimensions and tolerances of flywheel housings for reciprocating internal combustion engines ISO title: Flywheel housings for reciprocating internal combustion engines Nominal dimensions and tolerances UDC629.11
2、3.3/.5:62 213 562(083.3)BSAU226:1988 This BritishStandard, having been prepared under the directionof the Automobile Standards Committee, was published under the authority ofBoard of BSI and comesintoeffect on 31August1988 BSI02-2000 The following BSI references relate to the work on this standard:
3、Committee reference AUE/13 Draft for comment82/79772DC ISBN 0 580 16727 5 Committees responsible for this BritishStandard The preparation of this BritishStandard was entrusted by the Automobile Standards Committee (AUE/-) to Technical Committee AUE/13, upon which the following bodies were represente
4、d: Department of Transport (Highways) Freight Transport Association Institute of Road Transport Engineers (Incorporated) London Regional Transport Ministry of Defence National Bus Company Road Haulage Association Ltd. Society of Motor Manufacturers and Traders Limited Amendments issued since publica
5、tion Amd. No. Date of issue CommentsBSAU226:1988 BSI 02-2000 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope and field of application 1 2 References 1 3 Nominal dimensions and tolerances 1 4 Relationship of pilot bearing bore to flywheel housing 3 5 Mating part
6、 flange 4 Annex Procedure for measuring bore eccentricity and face deviation 5 Figure 1 Flywheel housing 2 Figure 2 Bolt or screw hole spacing 3 Figure 3 Depth of pilot bearing bore 4 Figure 4 Resultant total indicator reading, I R 6 Table 1 Flywheel housing dimensions and tolerances 1 Table 2 Tappe
7、d holes and bolt or screw spacing and dimensions 2 Table 3 Depth of pilot bearing bore 3 Table 4 Data chart 5 Publications referred to Inside back coverBSAU226:1988 ii BSI 02-2000 National foreword This BritishStandard has been prepared under the direction of the Automobile Standards Committee and i
8、s identical with ISO7648:1987 “Flywheel housings for reciprocating internal combustion engines Nominal dimensions and tolerances”, published by the International Organization for Standardization (ISO). Terminology and conventions. The text of the International Standard has been approved as suitable
9、for publication as a BritishStandard without deviation. Some terminology and certain conventions are not identical with those used in BritishStandards; attention is drawn especially to the following. The comma has been used as a decimal marker. In BritishStandards it is current practice to use a ful
10、l point on the baseline as the decimal marker. Wherever the words “International Standard” appear, referring to this standard, they should be read as “BritishStandard”. The Technical Committee has reviewed the provisions of ISO1101 and ISO7649, to which reference is made in the text, and has decided
11、 that they are acceptable for use in conjunction with this standard. A related BritishStandard to ISO1101 is BS308 “Engineering drawing practice” Part3 “Geometrical tolerancing”. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are
12、 responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International Standard Corresponding BritishStandard ISO273:1979 BS4186:1984 Specification for clearance holes for metric bolts and screws (Ident
13、ical) Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the ins
14、ide front cover.BSAU226:1988 BSI 02-2000 1 1 Scope and field of application This International Standard specifies the nominal dimensions and tolerances of flywheel housings for reciprocating internal combustion engines, in particular those which affect inter-changeability with mating parts. It appli
15、es to reciprocating internal combustion engines except engines for aircraft and passenger cars. Flywheel housings of size codes1 to4 are recommended for commercial vehicles and buses. 2 References ISO273, Fasteners Clearance holes for bolts and screws. ISO1101, Technical drawings Geometrical toleran
16、cing Tolerancing of form, orientation, location and run-out Generalities, definitions, symbols, indications on drawings. ISO7649, Commercial vehicles Clutch housings for internal combustion engines Nominal dimensions and tolerances 1) . 3 Nominal dimensions and tolerances 3.1 Flywheel housing SeeFig
17、ure 1 and Table 1. Table 1 Flywheel housing dimensions and tolerances 1) At present at the stage of draft. Dimensions in millimetres Size code A Run-out (assembled flywheel housing) B D a nom. tol. t nom. min. 02 01 00 0 1/2 1 2 3 4 5 6 1245 1010,00 787,40 647,70 584,20 511,18 447,68 409,58 361,95 3
18、14,32 266,70 +0,25 0 +0,25 0 +0,25 0 +0,25 0 +0,20 0 +0,13 0 +0,13 0 +0,13 0 +0,13 0 +0,13 0 +0,13 0 not applicable 0,47 0,39 0,35 0,31 0,27 0,25 0,25 0,25 0,25 1400 1165 883 711 648 553 489 451 404 356 308 10 10 8 8 8 8 8 8 8 8 8 NOTERun-out tolerances t shall be measured on the assembled engine mo
19、unted on its supports in accordance with the annex. (SeeISO1101 for definition of run-out.) a Dimension D relates to flywheel housings without rubber sealing. However, this dimension may be increased if a rubber seal is necessary. BSAU 226:1988 2 BSI 02-2000 3.2 Bolt or screw spacing and size 3.2.1
20、Dimensions and tolerances SeeFigure 1 and Table 2. Table 2 Tapped holes and bolt or screw spacing and dimensions Figure 1 Flywheel housing Size code Tapped holes Recommended thread engagement C nom. mm (seeFigure 1 and Figure 2) Number Size 02 01 00 0 1/2 1 2 3 4 5 6 24 24 16 16 12 12 12 12 12 8 8 M
21、16 M16 M12 M12 M12 M10 a M10 M10 M10 M10 M10 For cast iron flywheel housing 1,5 ? nom. of bolt or screw For aluminium flywheel housing 2 ? nom. of bolt or screw 1340,00 1105,00 850,90 679,45 619,12 530,12 466,72 428,62 381,00 333,38 285,75 NOTE24 tapped holes are optional for aluminium flywheel hous
22、ings of size code1. a M12 may be used for high engine torque applications.BSAU226:1988 BSI 02-2000 3 3.2.2 Spacing Tapped holes shall be spaced equally on each side of the vertical and horizontal axis lines as shown in Figure 2. 4 Relationship of pilot bearing bore to flywheel housing The depth of t
23、he pilot bearing bore (seeE in Figure 3) extends from the flywheel housing face to a shoulder in the flywheel, to a shoulder within the crankshaft or to the crankshaft flange face. Table 3 Depth of pilot bearing bore Figure 2 Bolt or screw hole spacing Dimensions in millimetres Size code E nom. E no
24、m. optional for: double plate clutches when extra-heavy flywheel is used overcentre clutch 02 01 00 0 1/2 1 2 3 4 5 6 265 265 100 100 100 100112 a 100112 a 100 100 71 71 133,4 133,4 133,4 133,4 71 100 a An E dimension of112mm is optional for flywheel housing size codes1 and2 when the clutch shaft be
25、aring is located in the pilot bearing bore of the flywheel or crankshaft end, i.e.when the bearing is not located in a separate carrier.BSAU 226:1988 4 BSI 02-2000 5 Mating part flange (for example, clutch housings) The dimensions and tolerances of clutch housings for reciprocating internal combusti
26、on engines are given in ISO7649. Limits and fits of the pilot diameter of the mating part are at the discretion of the manufacturer of that component. The manufacturer shall also specify the tolerances of form and position of the mating part flange. The clearance holes of the mating part flange shal
27、l have the same location as specified under3.2.2 and shall be in accordance with ISO273. Figure 3 Depth of pilot bearing boreBSAU226:1988 BSI 02-2000 5 Annex Procedure for measuring bore eccentricity and face deviation (This annex forms an integral part of the Standard.) A.1 Scope This annex provide
28、s a uniform procedure for measuring bore eccentricity and face deviation (run-out) of flywheel housings after assembly to an engine. Limits of bore eccentricity and face deviation are given in Table 1. A.2 Measuring procedures A.2.1 General A.2.1.1 A dial indicator with rigid extension bars is requi
29、red. A.2.1.2 Surfaces which are to be measured shall be free from dirt and burrs. A.2.1.3 Prepare a chart as shown in Table 4 to help in determining bore eccentricity. A.2.2 Eccentricity of housing A.2.2.1 Mount the indicator base on the flywheel or crankshaft flange as close as possible to the hous
30、ing pilot bore to minimize deflection. A.2.2.2 Adjust the indicator point to be perpendicular to the housing pilot bore and set at zero in the6oclock (mandatory) position (lower vertical). A.2.2.3 Slowly rotate the crankshaft and record the indicator reading along with the appropriate positive or ne
31、gative sign at the9oclock(a),12oclock(b), and3oclock(c) locations. Confirm that the6oclock reading is still zero. Record the readings on line A in Table 4, being sure to include the positive or negative sign. Table 4 Data chart CAUTION Sign designation relative to direction of indicator tip movement
32、 is not the same for all indicators. For all measurements in the calculations carried out in accordance withA.2.2, outward movement of the indicator tip with respect to the centre of the bore being measured is to be considered a negative reading. Designation 6oclock 9oclock 12oclock 3oclock A B C D
33、E F Observed indicator reading Adjustment for bearing clearance Half-bearing clearance adjustment Total corrected vertical indicator reading Corrected horizontal indicator reading Total horizontal indicator reading 0 I v = I H = a = d/2= E 1 = b = d = c = d/2= E 2 I V = b + d E 1 = a + d/2 E 2 = c +
34、 d/2 I H = E 1 E 2 I R I v () 2 I H () 2 + = BSAU 226:1988 6 BSI 02-2000 A.2.2.4 Position the indicator at the12oclock location and determine d, the adjustment for clearance in the main bearing adjacent to the flywheel, by an appropriate method, for example by raising the crankshaft to its upper lim
35、it. Record the adjustment for bearing clearance on line B in Table 4 in the12oclock column. This value shall always be positive. NOTEA floor-mounted support with a padded prybar or other suitable means can be used to raise the flywheel; however it should not be forced beyond the point where the bear
36、ing clearance has been removed, nor should the housing be used as a fulcrum. A.2.2.5 Correct the12oclock reading obtained inA.2.2.3 by algebraically adding the adjustment for bearing clearance to it. This is the corrected total vertical indicator reading (I V ). Record this value on line D in Table
37、4. A.2.2.6 Correct the3oclock and9oclock readings fromA.2.2.3 by algebraically adding an amount equal to one-half of the adjustment for bearing clearance determined inA.2.2.4 to each of them. This can be done by taking the clearance adjustment determined inA.2.2.4, dividing it by two, and entering i
38、t on line C in the3oclock and9oclock columns. Again, this value will always be positive. The readings, corrected for bearing clearance, can then be obtained by algebraically summing the values in lines A and C of the3oclock and9oclock columns. These values shall be denoted as E 1and E 2and entered o
39、n line E in Table 4. A.2.2.7 Determine the horizontal indicator reading (I H ) by taking the algebraic difference between the corrected3oclock and9oclock readings (I H = E 1 E 2 ). This value is to be entered on line F in Table 4. Figure 4 Resultant total indicator reading, I RBSAU226:1988 BSI 02-20
40、00 7 A.2.2.8 Determine the resultant total indicator reading (I R ) of the housing or adapter by locating the intersection point of the total vertical indicator reading (I V ) and the total horizontal indicator reading (I H ) in Figure 4, or calculate as follows: I R =(I v ) 2 + (I H ) 2 NOTEThis va
41、lue (I R ) is consistent with a total indicator type reading as are the limits specified in Table 1. It is not eccentricity as such. Actual eccentricity is equal to one-half of this value. A.2.3 Face deviaton of housing A.2.3.1 Mount the indicator base in accordance withA.2.2.1. A.2.3.2 Adjust the i
42、ndicator point to be perpendicular to the face. A.2.3.3 After eliminating the crankshaft end play, e.g.,by tilting the crankshaft or by inclining the engine approximately15 to20 , set the dial indicator to zero in the6oclock (not mandatory) position. A.2.3.4 Taking care to keep the end play eliminat
43、ed in the same direction as in the6oclock position, rotate the crankshaft one complete revolution to determine the total indicator reading. A.2.3.5 Compare the total indicator reading with the limit specified in Table 1.8 blankBSAU226:1988 BSI 02-2000 Publications referred to See national foreword.B
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