1、TECHNICAL REPORT ISO/TR 10657 First edition 1991-05-15 Explanatory notes on IS0 76 Notes explicetives SW /SO 76 Reference number ISO/TR 10657 : 1991 (E) ISO/TR 106!3 : 1991 (E) Contents 1 Scope,. 1 2 Brief History . 1 2.1 ISO/R76-1958 . 1 2.2 IS0 76- 1978 . 2 2.3 ISO76-1987 . 3 3 Basic Static Load R
2、atings . 6 3.1 Basic static radial load rating C,for radial ball bearings. . 10 3.1.1 Radial and angular contact groove ball bearings. . IO 3.1.2 Self-aligning ball bearings 12 3.2 Basic static axial load rating C, for thrust ball bearings. . 14 3.3 Basic static radial load rating - type 2, when the
3、 subject is still under technical development or where for any other reason there is the future but not immediate possibility of an agreement on an International Standard; - type 3, when a technical committee has collected data of a different kind from that which is normally published as an Internat
4、ional Standard (“state of the art”, for example). Technical Reports of types 1 and 2 are subject to review within three years of publi- cation, to decide whether they can be transformed into International Standards. Technical Reports of type 3 do not necessarily have to be reviewed until the data th
5、ey provide are considered to be no longer valid or useful. ISO/TR 10657, which is a Technical Report of type 3, was prepared by Technical Com- mittee ISO/TC 4, Rolling bearings, Sub-Committee SC 8, Load ratings and life. ISO/TR 10657 has been prepared for the guidance of users of IS0 76 : 1987, Roll
6、ing bearings - Static load ratings. It is a purely scientific document intended for use by specialists in this field, and it is not envisaged that it will become an International Stan- dard. Annexes A, B and C form an integral part of this Technical Report. TECHNICAL REPORT ISO/TR 10957 : 1991 (E) E
7、xplanatory notes on IS0 76 1 Scope This Technical Report gives supplementary background information regarding the derivation of formulae and factors given in IS0 76, Rolling bearings - Static load ratings. 2 Brief History 2.1 ISO/R 76 - 1958 The IS0 Recommendation R 76, Ball and Roller Bearings - Me
8、thods of Evaluating Static Load Ratings, was drawn up by Technical Committee ISO/TC 4, Ball and Roller Bearings, the Secretariat of which is held by the Sveriges Standardiseringskommission (SIS). This Recommendation is based On the studiesl*, 2 by A. Palmgren and so on. It is defined in the Recommen
9、dation that the basic static load ratings correspond to a total permanent deformation of rolling element and raceway at the most heavily stressed rolling element/ raceway contact ef 0,OOOl of the rolling element diameter. And then the Standard values confined to the basic static load ratings for spe
10、cial inner design rolling bearings are laid down. * Figures in brackets indicate literature references in annex C. ISO/TR 10667 : 1991 (E) Technical Committee ISO/TC 4 discussed the questions dealt with by the IS0 Recommendation at the following meetings: the third meeting, held in Ggteborg, in Sept
11、ember 1953, the fourth meeting, held in Madrid, in May 1955, the fifth meeting, held in Vienna, in September 1.956. At the third meeting of the Technical Committee, Working Group No. 3 was appointed to assist the ISO/TC 4 Secretariat in preparatory work and in drawing up proposals. The Working Group
12、 composed of Germany, Sweden and USA held the following meetings: the first meeting, held in Madrid, in May 1955, the second meeting, held in Vienna, in September 1956. On 4th June 1957, the Draft IS0 Recommendation was sent out to all the IS0 member Bodies and was approved by 28 (out of a total of
13、38) Member Bodies. The Draft IS0 Recommendation was then submitted by correspondence to the IS0 Council, which decided, in December 1958, to accept it as an IS0 Recommendation. 2.2 ISO 76 - 1978 The Working Group No. 3 was transformed into X8 at the 13th meeting held in Paris in May 1972. The SC 8 S
14、ecretariat proposed to include the revision of ISO/R 76 in the future work at the first meeting held in London in November 1973, and SC 8 requested its Secretariat to prepare a Draft Proposal for an International Stan- dard replacing ISO/R 76 and it was decided that this proposal should be submitted
15、 to the SC 8 member Bodies for consideration prior to 1 October 1974 (SC 8 RESOLUTION 21, 21 London 1973). 2 ISO/TR 10667 : 1991 (E) The SC 8 Secretariat distributed a DRAFT PROPOSAL (Revision of ISO/R 76) in July 1974. The TC 4 decided to include the revision of ISO/R 76 in its. pro- gramme of work
16、 (TC 4 RESOLUTION 514, item No. 132) and SC 8 Sec- retariat was requested to prepare a Draft Proposal (SC 8 RESOLUTION 38, 13 Miami Beach 1974). As a result, the Secretariat submitted a DP 3 3 in January 1976. The Draft Proposal DP 76 was accepted by correspondence by 6 of the 8 Members of SC S. Of
17、the remaining two, Japan would prefer further study and USA its counter proposal, document 4/8 N 64 4. The DIS 76 was then submitted to the IS0 Central Secretariat. After the DIS had been irppro.xd by the IS0 Member Dodies, the IS0 Council decided in June 1978 to accept it as an International Standa
18、rd. This Standard adopted the SI unit newton and was revised in total, but without essential changes of substance. However, values of Xo and Yo far the nnminal contact angles 15 and 45 for angular con- tact groove ball bearings were added to the table which shows the values of X0 and Y. in the formu
19、lae to calculate the static equiva- lent radial loads of radial ball bearings. 2.3 I50 76 - 1987 During the revision of ISO/R 713 - 1958, USA had in 1975 submitted a counter proposal 4 f or the basic static load ratings based on a calculated contact stress. 3 ISO/TR 10657 : 1991 (E) The Secretariat
20、requested a vote on the revision of the static load ratings based on a contact stress level in January 1978 and after- ward circulated the voted results in June 1978, and the item No. of revision work had became No. 157 of the programme of work of n: 4. This Draft Proposal DP 76 was dealt with at th
21、e following TC 4 meetings: 15th meeting, held in Moscow, in April 1977, 16th meeting, held in London, in November 1979, 17th meeting, held in Budapest, in May 1983, and then, dealt with at the following SC 8 meetings: the third meeting, held in London, in November 1979, the fourth meeting, held in B
22、udapest, in May 1983, the fifth meeting, held in Arlington, in November 1984. The following resolutions for the contents of the Standard were adopted during the third meeting to the fifth meeting: SC 8, considering the proposals made in the documents 4/8 N 75 15 and 4 N 865 c63 , as well as the comm
23、ents made by TC 4 Members and that several SC 8 members expressed a need for updating IS0 76, agreed to contiriue its study taking into account the possibility of using either permanent deformation or stress level as a basis for static load ratings (SC 8 RESOLUTION 45, 5 London 1979) and SC 8 reques
24、ted its Secretariat to prepare a new draft. The new draft should be prepared with the principles and formulae of the document 4/8 N 75, and to include levels of contact stress for various rolling element contact stated to be generally corresponding to 4 ISO/TR 106R : 1991 (E) a permanent deformation
25、 of 10 -4 Dw at the centre of the most heavily stressed rolling element/raceway contact. For roller bearings a stress level of 4000 MPa was agreed (SC 8 RESOLUTION 51, 4 Budapest 193) and then SC 8 agreed, by a majority vote, that static load ratings should correspond to calculated contart stresses
26、of 4000 MPa for roller bearings, 4600 MPa for self-aligning ball bearings and 4200 MPa for all other ball bearings to which the Standard applies (SC 8 RESOLUTION 56, 3 Arlington 1984). Moreover, SC 8 recommended the document 4/8 N 121 7) , amended in accordance with SC 8 Resolution 56, as a revised
27、IS0 76 (SC 8 RESOLUTION 57, 4 Arlington 1984). For these calculated contact stresses, a total permanent deformation occures at the centre of the most heavily stressed roliing element /raoeway contact, and its deformation is approximately 0,OOOl of the rolling element diameter. The DIS 71 ws submitte
28、d to the IS0 Central Secretariat 1985, and after it had been approved by the IS0 Members, the IS0 Council de- cided in February i987 to accept it as an International Standard. Further-more, SC 8 decided at it5 fifth meeting in April 1986 that r;upplementary background information, regarding the deri
29、vation of formulae and f+ctors given in IS0 7h, should be pub1 i shed as a Tech- nical Report (SC 8 RESOLUTION 71, 11 Hangzhou 1986). ISO/TR 10657 : 1991 (E) 3 Basic Static Load Ratings (1) Basic equation for point contact The relationship between a calculated contact stress and a rolling element lo
30、ad within an elliptical contact area is given as follows a) ) g-2 2Aab where r= calculated contact stress, PIPa, a = major semi axis of the contact ellipse, mm, b = minor semi. axis of the contact; ellipse, mm, Q U normal force between rolling element and raceway, N) X = distance in a-direction, mm,
31、 Y = distance in b-direction, mm . It is concluded that the maximum calculated COntACt stress (=v, and l- m - * where Eo a E l-V2 E - 2.07 x lo5poJ v= 0,3 . Consequently, L Q a 2,7621732 x lO-5 2 FL, . lzP (3-11) ISO/TR 10657 : 1991 (E) 3.1 Basic static radial load rating C r for radial ball bearing
32、s + y + 2f1 F(P) = -lFY i(e) 2*-1 (3-13) 2fi.( e) where 3.1.1 Radial and angular contact groove ball bearings The curvature sum Z/3and curvature difference F(p) of radial and a.nmsJ contact groove ball bearings is given by the following equation, zP+2=x) 3: fey+ W ri P inner ring groove radius, mm ,
33、 r e P outer ring groove radius, am . Substituting equation (3-U) into equation (3.7), Q= 6,4762065 x 10 -1ogx E(u) , 2 3 Y 2f-,. ) qax l (3-14) lTFy 2fi(e) Substituting equations (3-12) and (3-14) into the following equation Cl01 , furthermore exchanging Q c = or for Qmax, (3-15) ISO/TR 10667 : 199
34、1 (E) where C or = basic static radial load rating, N ) Z = number of balls per row Q. max = maximum normal force between rolling element and raceway, N ) S is a function of the loaded zone parameter &. If one half of the balls are loaded then S = 4,37 applies. A common value used in general bearing
35、 calculations is S = 5, which leads to a rather conservative estimate of the maximum ball load, a = nominal contact angle,d J C or = 0,2ZQmaxcosa . Consequently, (3-16 C 3 rmax or = 0,2 x 6,4762065 x 1o-1ox (4000) (- 4000) Ic E(X) 2 1) 2 2* y ZDwoosa ) l T Y - 2fi(c) where the upper sign refers to t
36、he inner ring and the lower sign refers to the outer ring. Therefore, introducing the number of rows i of balls, C or - foiZDtcoaa , where f. p factor which depends on the geometry of the bearing components and on appli- cable stress level 2 . (3-17) (3-18) 11 ISO/TR 10667 : 1991 (EI The formula app
37、lies to bearings with a cross-sectional xaceway groove radius not larger than 0,52 D, in radial and angular contact groove ball bearing inner rings, and 0,53 D, in radial and angular contact groove ball bearing outer rings and self-aligning ball bearing inner rings. The load-carrying ability of a by
38、 the use of a smaller groove a larger groove radius. In the value of f, shall be used. For an inner ring with fi = bearing is not necessarily increased radius, but is reduced by the use of latter case, a correspondingly reduced 0952, r) Gax 3 E(U) L f. = 2,072(-& U( 2+& 1) P a- 1,04 and for an outer
39、 ring with fe = 0,53, (3-19) (3-20) The smaller value between the f. values calculated from equations (3-19) and (T-20) shall be adopted. The values of factor f. on table 1 in IS0 76 - 1987 are calculated from substituting the values for X, E(K) and Y= Dwcos a/D shown PW in table A.1 I and Gax = 4200 MPa into the above equation. 3.1.2 Self-aligning ball bearings The curvature sum x:/,of self-aligning ball bearings is given by the following equation for an outer ring, 12 (3-21)
