1、UDC 621.833.1 : 621.753.1 DEUTSCHE NORMEN August 1978 d s; 0- g E.!: E“ !g E ;z ES2 ETC -Om c 00 - O0 DoLC CO. c my m- g 0 50 %; ?! a5 g $a zf: 50 mm) these tolerances are- sometimes too large, particularly for fH and F, when it is desired to achieve a good contact pattern. In such cases the tooth t
2、race tolerances need to be made smaller than the other tolerances (see Sections 4.1 and 4.2) or else interchangeable manufacture has to be abandoned in favour of pairwise gear matching. The difference (fHpI - fp,l in this case should be smaller or at most equal to the tolerance value of the Standard
3、. In particular, the flanks should always be set back at the ends. No tolerances for the tooth trace waviness fm are laid down in the Standards. For special applications, Stand- ards are applied in which tolerances for few, e. g. for turbine gear transmissions BS 1807 and BS 1488. For the generator
4、total deviation FE (see DIN 3960) it is generally possible to accept the same values as for fHp. In similar fashion to Fig. 1 for the profile form, so also for the tooth trace can a specific configuration, termed crowning, also be prescribed. Fig. 2 shows how, with prescribed crowning Cb.taken into
5、account, the values for Fg, fHp and fpf are derived from the tooth trace test pattern. In the evaluation of the test pattern the width has to be reduced by 10% at each tooth end, assuming a minus deviation. Crowning imparts an improvement in functional terms, i. e. the effect of the tooth trace angl
6、e deviation fH is partly compensated. This means that in certain circum- stances it is possible with crowned gear teeth to select a coarser gear tooth quality than with non-crowned gears, see VDI/VDE 2612. Page 8 DIN 3961 li I- C + Figure 1. Altered pattern of permissible range of profile deviations
7、 (examples) Figure 2. I I l! Root rip AA, AA BB BB, B“B“ CC, C“C“ F fHP f f cb cb actual Corrected base lines bounding the test pattern within the evaluation range. Averaging actual tooth flank Actual tooth traces bounding the test pattern within the evaluation range. Non-corrected nominal tooth tra
8、ces through the points of intersection of the averaging actual tooth trace BB with the boundary lines of the evaluation range. Tooth trace total deviation; results from the distance apart of the corrected base lines AA and AA as measured at right angles to the chart feed. Tooth trace angle deviation
9、; results from the distance apart of the nominal tooth traces CC and C“C“. Tooth trace form deviation; results from the distance apart of the actual tooth traces BB and B“B“ as measured at right angles to the chart feed. Nominal crowning Actual crowning DIN 3961 Page 9 6.3 Working test for fine gear
10、 tooth qualities The permissible working deviations apply in principle to the testing of a working gear with an error-free standard (master gear). In practice it is necessary to limit the checking to determining that the deviations of the master gear compared with those of the test gear are sufficie
11、ntly small (approximately in a 1 : 5 ratio). Hence it would not be meaningful to state permissible working deviations for the gear tooth quality range from 1 to 4, since in practice there are no adequately error-free standard gears available for this purpose, or gears with known error pattern. Never
12、- theless, a working test of two gears of approximately the same gear tooth quality is sometimes carried out. In this case, however, the test must be repeated with the flanks interchanged (left and right). If there deviations are Fil and Fiz a measured value of F = VF + F; will be expected according
13、 to the quadratic error propa- gation law. In a working test of two gears (master gears) having approximately the same gear tooth quality, there- fore, only fi= 1.4 times the tolerance value of this qual- ity can be accepted. Hence for these applications the standardized quoting of permissible worki
14、ng deviations is still meaningful for fine gear tooth qualities. A binding quality test according to this method is how- ever only possible if the uncertainty of measurement can be kept small enough, cf. VDINDE 2608. 6.4 Pitch-span deviations over discretionary pitch-spans In general the tolerancing
15、 and testing of pitch-spans over 45“ and 180 of the gear circumference according to the values Fp s/8 and Fp in DIN 3962 Part 1 is perfectly ade- quate. ln some cases, however, and particularly where high-speed gears are involved, it may be necessary in certain circumstances to further restrict the
16、pitch-span deviations over discretionary pitch-spans. Their values are found from the formula or the diagram in DIN 3962 Part 3 and they require separate agreement. A pitch-span measurement can be evaluated by plotting the positive and negative tolerance values on tracing paper versus the number of
17、teeth z. The scales of Fp and z must agree with those of the test chart, and in this the z axis must be at right angles to the Fpk axis. If the zero point of the diagram is moved along the pitch-span curve of the test chart, keeping the z axes parallel, the pitch- span curve must lie at all times wi
18、thin the two tolerance curves, Fig. 3. Another method is to determine the pitch-span deviation Fpk and the associated span at the point of maximum increase in the test chart, Fig. 3 right. This measured value of Fp is then compared with the value permitted accord- ing to the diagram in DIN 3962 Part
19、 3 for the same span. 6.5 Individual pitch deviations and pitch errors If mavericks occur in individual pitch measurements, it is permissible to make measurements at different points on the flanks and to derive averages for each pitch. The resulting series of measurements is then used as the basis f
20、or assessing the individual pitch deviation and pitch error. No further mavericks are permissible in this. When making pitch measurements with two spherical tracers it is important to ensure that the second tracer contacts the flanks each time at exactly the same spot as the first tracer in the prec
21、eding pitch. Apart from the pitch deviation tolerances laid down in DIN 3962 Part 1 and Part 3 there are also other character- istics for assessing pitch, e. g. the arithmetic mean or root mean square values of the pitch deviations. They may form the subject of separate agreements;see also VDI/ VDE
22、2605. Figure 3. Evaluation of pitch-span measurement Page 10 DIN 3961 Other Standards and codes DIN 3999 Symbols for gear teeth VD INDE 2605 Circular pitches and plane angles. Fundamental terms for angle dimensions, angle measurements, angle standards and their errors VDI/VDE 2608 Single-flank and t
23、wo-flank working test for straight and helical cylindrical gears with involute profile VDI/VDE 2612 Profile and tooth trace test for cylindrical gears with involute profile, Part 1 Profile testing, Part 2 Tooth trace testing VDi/VDE 2613 Pitch and concentricity tests on gear teeth VDI/VDE 3336 Cutti
24、ng cylindrical gears with involute profile, metal-removal processes Literature Winter, H.; Seifried, A.: Verzahnungsfehler. Statistische Ermittlung natrlicher Zusammenhnge und Normung von Toleranzen (Gear tooth errors. Statistical determination of natural relationships and standardizing of tolerance
25、s). Seifried, A.: Zahnrad-Teilungsfehler. Statistische Ermittlung der Zusammenhnge mit anderen Verzahnungsfehlern (Gear tooth pitch errors. Statistical determination of relationships with other gear tooth errors). VDI-Berichte No. 105 Kagerl, H. G.; Wrpel, H.: Fertigungsgerechte Relationen zwischen
26、den geometrischen Abweichungen an Stirnrdern (Product ion-or iented re1 at ionsh ips between the geomet r ical dev at io ns on cy I ind r ical gears). WISSENSCHAFT L. ZEITSCHR. d. TH. Magdeburg 11 (1967) No. 2, pp. 201-210. Kagerl, H. G.; Dulich, W.: Fertigungsgerechte Relationen Einflankenwlzabweic
27、hunglEinflankenwIzsprung - Einzel- abweichungen (Production-oriented relationships, singlwflank working deviatiodsingle-flank working error - individual deviations). FERTIGUNGSTECHNIK UND BETRIEB 21 (1971) No. 8, pp. 455-458. WERKSTATT UND BETRIEB 98 (1965) NO. 10, pp. 765-771. (1967) pp. 141-143. E
28、xplanations This Standard is intended to contribute to the further development of the International Standard on tolerances for cylindrical gears with involute teeth IS0 1328 - 1975. It is recommended that comparative data derived from experience be collected for making available in due course to the
29、 responsible IS0 committee. The DIN gear tooth tolerance system in use so far, the principles of which have not altered, has for the most part proved itself in practice. Only with regard to a few points was a general redefining of tolerances necessary. This applies particularly to the permitted valu
30、es for single-flank working deviations, tooth trace deviations . and, to some extent, for pitch-span deviations. Apart from this, it has been shown in practice that for the same module the profile deviations do not become larger with increasing diameter (increasing number of teeth). The profile tole
31、rances therefore remain only module-dependent and no longer diameterdependent. The following survey in tabular form gives a general view of the alterations undertaken. The definitions, designations and symbols have been redefined in accordance with DIN 3960, DIN 3998 and DIN 3999. Newly added are to
32、lerances for total profile deviation, pitch-span deviation, tooth trace form devi- ation and tooth trace total deviation. Information on tolerance families, quality testing and test groups has also been added. The numerical specifying of tolerances derives from the equations in this Standard. The al
33、terations are listed in the last column of the survey Table. Additional alter- ations of the tabulated numerical data in DIN 3962 Part 1 to Part 3 and DIN 3963 result from the fact that the module and diameter ranges have been regraded and from the fact that the values in the old Standards cal- cula
34、ted from the tolerance equations had for the most part been rounded upwards, whereas in the new Stand- ards they have been rounded up or down to the nearest preferred number. The dimension range has been enlarged in the upward direction to module rn = 70 mm and diameter d = 1 O O00 mm. Regardless of
35、 whether all deviations are measurable, the numerical values in the tables of DIN 3962 Part 1 and DIN 3963 have been listed com- pletely in the interests of future applications. The module range m 1 mm has been deleted, see in this connection DIN 58 405. The arrangement of the toler- ance Standards
36、has been altered so that the tooth trace deviations have been grouped with the individual devi- ations in DIN 3962 Part 2, whilst DIN 3963 contains only working deviations and DIN 3967 only the system of gear fits. When the “Gear tooth tolerances“ Sub-committee started revising the Standards on tole
37、rances for cylindri- cal gear teeth it was faced with the question whether the tolerances contained in IS0 1328 - 1975 could be taken over complete. After a thorough examination the com- mittee came to the conclusion that this would not be expedient for the purposes of German industry. The principal
38、 objections to IS0 1328 - 1975 are its big tolerances for the twoflank working deviation, con- centricity deviation and pitch-span deviation and the large amount of spread in their relationship to the other tolerances. The Figures below present some examples of tolerances according to the new Standa
39、rds and compare them with IS0 1328 - 1975 and AGMA 390.03. (For this purpose AGMA gear tooth quality 11 was assumed equal to DIN gear tooth quality 7 and AGMA gear tooth quality 9 equal to DIN gear tooth quality 9). The best agreement is found with the profile and tooth trace total deviations, whils
40、t the biggest discrepancies occur in the two-flank working deviations and concentricity deviations. The latter however only to the middle gear tooth qualities. Because of the unequal increments in ISO, the agreement improves with the high and low gear tooth qualities. DIN 3961 Page 11 Symbol and des
41、ignation Alteration, redefinition Tolerance equations New Old , Conceptual content Now only d module- dependent, m no longer diameter- dependent at -= z=25 . 100 approx. same as before ff Flank form error F, Base circle error ff Profile form fHa Profile angle deviation deviation Unchanged Unchanged
42、fHD.cFg in DIN 3962 Part 1 to Part 4, No- vember 1952x edit ions Fp Total pitch deviation deviation Fpk Pitch-span F, 218 Pitch-span deviation over “/a of periphery Fr Concentricity deviation Redefined according to IS0 1328 - 1975 Ft Cumulative pitch error - - fr Concentricity error Only moduledepen
43、dent! fi Single-flank work- ing error Ft Total profile dev at ion fi Single-flank work- Unchanged ing error fpf Tooth trace form deviation fH Tooth trace angle deviation - f Flank alignment error Fp Tooth trace total deviation - Redefined fP Individual pitch ft Individual pitch error Unchanged devia
44、tion Reduced 10 - 20% foe Normal base pitch fe Normal base pitch Unchanged deviation error Reduced 10 - 20% flJ Pitch error I fU Pitch error I Unchanged f, = 1.25 fp instead of previously fu =t; Reduced for large diameters! Made more precise Fp A Maximum Redefined Redefined i Unchanged On basis of I
45、S0 1328 - 1975 dependent on pitch-span F, = 0,84 FY instead of previously F, = FI R, Tooth thickness fluctuation f8 Tooth thickness error Unchanged R, = 0.59 F, = 0.52 FI instead of previously f, = 0.7 fr = 0.7.Fj Fi Two-flank work- Fi Tooth flank working . Unchanged ing deviation error Unchanged 6
46、Two-flank work- fr Twoflank working Unchanged ins error error Somewhat increased Fi Single-flank work- ing deviation Fi Single-flank work- ing error Unchanged Considerably increased, with: From gear tooth quality 9: 9 = 1.6 instead of previously 1.4 Fi = 0,8 (Fp t Ff) Considerably increased, with: F
47、rom gear tooth quality 9: 9 = 1.6 instead of previously 1.4 Coordinated with fH and Fp Increase diminishing with width b (instead of proportional as hitherto) fi = OR7 (fp t Ff) Redefined Unchanged According to IS0 1328 - 1975 Page 12 DIN 3961 20( IJm 1 BC 160 14 12c 1 O0 80 60 w: 20 O Gear tooth qu
48、ality 7 (AGMA gear tooth quality 1 1) m=5mm b =50mm d=70mm I d=300mm Gear #ooth quality 9 (AGMA gear tooth quality 9) m=12mm b=120mm I d=lSOmm d=300mm Reference circle diameter d = 300mm Module m = 5mm DIN and IS0 gear too- quality _F 12 3 4 5 6 7 9 10 11 12 II III I1 II II 15 14 13 12 11 10 9 8 7 6 5 4 - AGMA gear tooth quality
