1、MIUTARY SPECIFICATION MIL-B-8942A (ASG) 16 NOVEMBER 1965 suPerseding m-a-8942(ASG ) 16 March 1964 BEARINGS, PLAIN, TPE UNED, SELF.ALIGNmG This specification has been approved by the Department or the Air Force and by the Bureau ot Naval Weapons. 1. SCOPE 1.1 This specification covers plain spherical
2、 baari.ngs ldlich are selfal1gni“ Hydrocarbon Bearings, Anti-Friction, Associated Parts and Sub-Assemblies, Packaging ot Hydrr.J4, Fluid, Petroleum Base, Aircraft, Missile, and Ordnance Lubri “:.ng Oil, Aircraft Turbine Engine, Synthetic Base Anti-Icing and Deicing-Defrosting Fluid Drmdngs, Engineer
3、ing and Associated Lists FED. TEST METHOD Paint, Varnish, Lacquer, and Related .aterials; Methods STD. NO. 141 or Inspection, Sampling, and Testing Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-B-8942A(ASG) Milita.r:r MIL-STD-10 MIL-STD-105 MIL
4、-STD-129 MS2123 0 HS21231 MS21232 MS21233 Surface Roughness, Waviness and La7 Sampling Procedures and Tables for LlSpection by Attributes Marking for Shipment and Storage Bearing; Plain, Self-Aligning, Grooved Outer Ring, TFE Lined, Wide Bearing, Plain, Self-Aligning, TFE Lined, Hide Bearing, Plain,
5、 Seil-Aligning, Grooved Outer Ring, TFE Lined, Narrow Bearing, Plain, Seil-Aligning, TFE Lined, Narrow (Copies of specifications, standards, drawings, and publications required by Buppliers in connection with specific procurement functions should be obtained from the procuring activity or as directe
6、d by the contracting officer.) 2.2 other publications.- The following document forms a part of this specifica tion to the extent specified herein. Unless otherwise indicated, the issue in effect on date of invitation for bids or request for proposal shall apply. Uniform Classification Committee Unif
7、orm Freight Classification Rules (Application for copies of the above publication should be addressed to the Unifor.a Classification Committee, 202 Chicago Union Station, Chicago, Ill., 60606.) 3. REQUIREMENTS 3.1 Qualification.- The bearing furnished under this specification shall be a product whic
8、h is in accordance with the applicable Military Standard (MS) and which has been subjected to and which has passed the qualification tests specified herein, and which has been listed on or approved for listing on the applicable Quali!ied Products List. 3.1.1 Product design change.- An7 change in pro
9、duct design or description will require requalification of the product to an extent determined by the qualitying activity. 3.2 Haterials.- The ball and outer race shall be in accordance with the appli cable MS. TFE shall be included in the liner in such manner that the bearing will conform to all re
10、quirements of this specification. 3.2.1 Plating.- Plating of the ball will be permitted, at the option of the manufacturer, and shall be in accordance dth QQ-C-320. 3.3 Design.- Bearing design hall conform to that shown 0.1 HS2l230, K.521231, 21232, and MS21233. 3.4 Constructiori.- The liner shall b
11、e so secured that all l“elative motion .dll be between the liner and the ball. The bearing shall not have loading slots. E:ccept as otherwise specified, the details of the working parts shall be optional. 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS
12、-,-,-3 .4. Dimensiuns a:nd tole!ci.llces.-Dilll3nsiorl. ;.1 .1I:i tclerances shall be as spe:i fied on the applicable !S. Dimensions not shown shcll be at the option of the matlu facturer. 3.4.2 Surface finish.- The spherical surtace ot the ball shc.ll have a finish ot roughness height rating (HHR)
13、a maximum in accordance dth IDLsTD-10. The bore, ball face, and outer race periphery shall. have a finish of RHR 32 ma.x:i.J:xImn. All other surfaces shall have a finish of RHR U5 maximum. Bearings shall be free of a.ny surface defects which may be detrimental to satisfactory installation, pertortl:
14、iaI1ce, 0: bing lite as detined in this specification. 3.4.3 Lubrication.-Init lubrication by the manufacturer ,:ill be permitted. Relubrication will not be permitted. 3.5 Performance.-3.5.1 Radial static limit load.- After the radial load listed on the applicable MS has been applied as specified in
15、 4.6.1, the total deflection of the bearing and !i;dure shall be less than 0.010 inch for bearings with a bore of 3/8 inch or less, 0.015 tor 7/16 and 1/2 inch, 0.07 for 9/16 and 5/8 inch, and 0.020 fOl: 3/4 inch and up. The permanent set shall be less than 0.003 inch. 3.5.2 Axial static l1mit load.
16、- After application of the axial load listed on the applicable MS, the permanent set shall be less than 0.0:5 inch. 3.5.3 Ultimate load.- No b-acture of the race or ball, 0:1; push-out of the bc.JJ. shall occur when 1.5 times the rad.1al or axial load limit is applied, as specified ill 4.6.1 or 4.6.
17、2. 3.5.4 Oscil.lation radial load.- The total liner wear of the bearill,g shall llOt exceed 0.006 inch when tested in accordance with 4.6.3 with the radial unidirect.ional load listed on the applicable MS. 3.5.5 Self-al1.g:nment.- The bearing shall be sell-a.ligr.i.ng and permit the angul810 displac
18、ement specified on the applicable MS. 3.5.6 No-load broska .1 c.ccordSllce dtb 4.6.4, the no load breaka torque shall be within the limits of the values specified on the appli cable MS. 3.5.7 Fluid comoatib111ty.- lVhen tested in accordance with 4.6.5, the bearings shall be compatible with the nuids
19、 listed in 4.6.5 and the total liner wear shall not exceed 0.006 inch 3.5.8 Corrosion resistance.- Corrosion resistance shall be determined in accord ance with Method 6201 of Fed. Test Method Std. No. 141. $uperficial ta:-nish which can be re:noved ilith a :h.mp cloth will not be cause 1“or reJec“t.
20、l.on. J. 5.9 HiRh te:nerature. - Vr.lell tested in accordance wit.h 4.6.7, undr the oscil hting load specified on the appl1caUe MS, the total liner wear shall not exceed 0.006 inch. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.-UrL-B-8942A (ASG)
21、3.5.10 Low ternroerature.- When tested accordance with 4.6.8, the no-load breakaway torque shall be not more than twice the maximum value specified on the applicable HS. 3.6 Interchangeability.- All parts having the same manufacturers part number shall be directly and completely interchangeable dth
22、each other ,-lith respect to in stallation and performance. The drawing number requirements of MIL-D-70327 shall govern changes in the manufacturers part numbers. 3.7 Identification of product.- Each bearing shall be permanently and legibly marked with the MS number and manufacturers part number, na
23、me, or trademark. Where practicable, identification shall appear on the side face of the outer race; otherwise, identification shall appear on the periphery of the bearing outer race. Metal impres sion stamping is prohibited. 3.8 l1orlananship.- The bearing shall be free of toolmarks, chatter waves,
24、 rust, grinding scratches, pits, or any other defects that may adversely affect their serv iceability. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for inspection.- Unless othedse specified in the contract or purchase order, the supplier is responsible for the performance of all inspection req
25、uirements as specified herein. Except as otherwise specified, the supplier may utilize his own facilities or any other commercial laboratory acceptable to the Govern ment. The Government reserves the right to perform any of the inspections set forth in the specification where such inspections are de
26、emed necessary to assure supplies and services conform to prescribed requirements. 4.1.1 Qualification test records.- The manufacturer shall maintain a record showing quantitative results for all tests required by this specification. This record shall be available to the purchaser and shall be signe
27、d by an authorized repre sentative of the manufacturer or the testing laboratory, as applicable. 4.2 Classification of tests.- The inspection and testing of the bearings shall be classified as: (a) Qualification tests (b) Quality conformance tests 4.3 Qualification tests.-4.3.1 Sampling instructions
28、.- Qualification test samples shall consist of 30 bearings of HS21232-8 and 9 each of all other sizes upon which qualification is desired. All bearings necessarJ for tests specified herein shall be furnished by the manufacturer SaJ:lples shall be identified as required and forwarded to the activity
29、designated in the letter of authorization from the activity responsible for qualification (see 6.3). 4.3.2 Certified test renort.- The manufacturer- shall furnish a certified test report showing that e manufacturers product satisactorily conorms to this specifi cation. The test report shall include,
30、 as a minimum, actual results of the tests speci fied herein. ).hen the report is submitted, it shall be accompanied by a dated drawing which completely describes the manufacturers product by specifying all dimensions and 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without
31、 license from IHS-,-,-tolerances, cotlpositio: of the ball C!ld c1.!ter race material, lubrica,t if used, coating or plating J and heat treatment. The manufacturer I s part number for each size shall be iIlcluded on the dral lg. 4.3.3 Tests.- Qualification tests shall include all the examinations an
32、d tests of this specification. The m1nimum number of samples per test shall be in accordance with table I. TABLE I. Qual.ification test samples Examination and tests Paragraph number Samples to be tested Examination of product 4.5.1 5 Preparation for delivery 4.5.2 5 Axial static limit load 4.6.2 3
33、Radial static limit load 4.6.1 3 Oscillating radial load 4.6.3 3 No-load breakaway torque 4.6.4 3 Fluid compatibility 4.6.5 J Corrosion resistance 4.6.6 3 High temperature 4.6.7 II .3 Low temperature 4.6.8 11 3 11 Half-inch size only. 4.4 Quality conformance tests.- The qual.ity conformance testing
34、of the bearings shall consist of the following examinations and test to determine con!or.mance of the bearings to the requirements ot this spec1:fication and the applicable Vs with regard to: (a) (b) (c) (d) (e) Di.mensions Identification ot product rlork:maru3hip Preparation tor deliver.y No-load b
35、reakaw torque (3.4.1) (3.7) (3.8) 4.4.1 Tests.- The bearing manufacturer shall be responsible tor accomplishing the quality conformallCe tests specified herein. 4.4.2 Lot.- The lot definition, formation, and size shall be in accordance with MIL-STD-l05. 4.4.3 Saapling.- The sample bearings shall be
36、selected in accordance with lflL-STD-I05, inspection level II, acceptable oualitf level of 1.0 percent, except that inspection for no-load breakaway torque (3.5.6) shall be 100 percent. 4.5 Examinations.-4.5.1 ation of product.- The bearings shall be examined to determine con formance to the require
37、ments of this specification and the applicable MS for material, plating, dimensions, finish, identification of product, workmanship, and requirements not covered by tests. 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NIL-B-8942A (ASG ) 4.5.2 Pre
38、paration for delivery.- Preservation, packaging, packing, and marking shall be inspected to determine conformance to section 5. 4.6 Test methods.- Unless otherwise specified, all tests shall be conducted at room temperature. 4.6.1 Radial static limit load.- The bearings shall be installed in a test
39、fixture as shown on figure 1, using a 0.000- to O.OOI-inch loose fit for the shaft and the housing. The use of differential temperatures for installation will not be allowed. A preload of 4 to 6 percent of the radial static load shall be applied to the bearing for 3 minutes, and the measuring device
40、 set at zero. The load shall then be increased at the rate of I percent of the specified load per second until it equals the radial static load limit. The total deflection shall be the reading at the radial static load limit after 2 minutes. The load shall then be reduced at the same rate to the pre
41、load value. The permanent set shall be the reading at preload. The ultimate radial load (see 3.S.3) shall be applied at the rate of I percent of the specified load per second. 4.6.2 Axial static limit load.- The test bearing shall be installed in a test fixture as shown on figure 2. Bearings shall f
42、it in the housing with a 0.000- to 0.001-inch loose fit. The hole in the support fixture for clearance of the ball shall be the nominal diameter of the ball plus double the thickness of the liner. The bearing shall be preloaded between 4 to 6 percent of the axial load limit. After holding for 3 minu
43、tes, the measuring device shall be set at zero. The load shall be increased at the rate of 1 percent of the specified load per second until it equals the axial static load limit. It shall be held for 2 minutes, then reduced at the same rate to the pre load value. The permanent set shall be the readi
44、ng at preload. The ultimate axial load shall be applied at the rate of 1 percent of the specified load per second. 4.6.3 Oscillating- radial load.- The bearing shall be installAd in a steel housing, using a slip fit and hardened shaft (RC50 minim) pressed into the bore.with O.OOOO-inch loose fit to
45、0.OOp5-inch interference fit. The bearing sb.all. be o npped. as to place the shaft in double shear with a minimum of haft bending. A dal LndLcaor or electronic pickup shall be so mounted that a.ny rada.l movement of the shat or,t.he bore of the bea.ring , . ith respect to the outer race can be meas
46、ured. The oscLllatng load snecified on the anplicable ! shall be applied and held for 15 minutes statlca.lly; at the end of this time: - the indicating device shall be set at zero and the oscillating test shall be started. ;lear readings shall include the wear from the first cycle on, The test shall
47、 be run in such manner that the ball is oscillated 25 degrees (50 degrees tot3.l) .at 10 cycles per minute for 5,000 cycles. One cycle sha:.l consist of rot3.tion from zero degrees to +25 degrees, return through zero degrees to -25 derees and return to! zero degrees. Te wear within the bea.ring.shal
48、l not exceed 0.006 inch at the end of 5,000 cycles. Sufficient intermediate re3.dings juring the test shall be recorded to :Jlot a gra.ph of “,ear (thousG.ndtis of 3.n inch) vs. life (cycles). In add:_tion, 1Jon cJmnletion of th: test, the loaded break3:tlay torque shall be as sD9cified in table II.
49、 4.6.3.1 Hie;h speed oscillation.- A bearing shall be installed in a fixture as sORcified in Lt.6.3. Tre test shall be run in such manner t.ha.t the ball is oscillated :tio degrees (20 degrees total) a.t 200 cycles per minute for 1,000,000 cycles ;1hile the bearing is loa:l.ed to one-third the oscillating load speCified ,In the app
