1、UDC 621.825.7.001.24 : 003.62 : 53.081 DEUTSCHE NORM August 1986 I - Power transmission engineering Flexible shaft couplings Parameters and design principles DIN I I 740 Part 2 I 1 Antriebstechnik; nachgiebige Wellenkupplungen; Begriffe und Berechnungsgrundlagen Supersedes March 1975 edition. In kee
2、ping with current practice in standards published by the International Organization for Standardization (/SO), a comma has been used throughout as the decimal marker. Contents Page 1 Scope and field of application . . 2.1 Coupling parameters, symbols and units . 1 Coupling performance characteristic
3、s, symbols and units. . 5 3 Coupling design . 2 Coupling parameters and perfor characteristics. 2.2 3.1 Types of stress . 3.2 Coupling design based on known performance characteristics . 3.3 Rough calculation of coupling performance characteri 3.4 3.5 Examples of calculation Higher order calculation
4、 methods. 1 Scope and field of application This standard applies to non-slip couplings with power transmission elements made both of partially flexible elastomers or elastomers which are flexible on all sides, and of flexible metallic spring elements. The calculation methods given in this standard f
5、or the design of flexible shaft couplings in- clude load factors derived from working practice and, in addition, are only valid for a linear two-mass vibration generating system under special operating conditions. In cases where simple rough calculations are not permissible for safety reasons or bec
6、ause of the technical complexity of the machineryfor which the calculation has to be made, and where account has to be taken of special factors of multi-mass systems with respect to temporary stress patterns, non-linear springs, backlash, etc., it will become necessary to use mathematically more com
7、plex calculation methods (e.g. to simulation technique). In subclause 3.4 only general recommendations have been given with respect to calcula- tion methods for modern plants, in order not to impede or influence progress in this field by preparing inappropriate standards. 2 Coupling parameters and p
8、erfomance characteristics 2.1 Coupling parameters, symbols and units See table 1 for parameters of flexible shaft couplings that are relevant to its design. The parameters shall be specified by the manufacturer of the coupling and shall apply to an ambient temperature lying between 10 and 30%. In th
9、e case of parameters that vary as a function of loading, temperature, rotational speed, frequency, etc., the dependency shall be given. This applies particularly to couplings which owe their flexibility to the elastic deformability of rubber elements. A distinction is to be made between static and d
10、ynamic valuesfor the design of a coupling. Dynamicvalues shall be indicated by the subscript “dyn“. It is common practice to specify the internal damping of elastic rubber elements in terms of the damping coefficient. It is only defined for linear coupling stiffness characteristics and for damping p
11、roportional to velocity. Generally valid damping assumptions relevant to common practice remain to elaborated. Continued on pages 2 to 12 Beuth Verlag GmbH. Berlin. has the exclusive right of sale for German Standards (DIN-Normen) 02 aa DIN 740 Part 2 Engl. Price group Siles No O109 Page 2 DIN 740 P
12、art 2 Table i. Coupling parameters - Syml Definition Torque that can be continuously transmitted across the entire permissible rotational speed range. Torque resulting from pulsating or alternating stress, which i coupling can resist without failure for a short period of time. During the total servi
13、ce life of the coupling, it shall be possible for the maximum torque resulting from pulsating stress to be absorbed for not less than lo5 cycles, and from alternating stress, for not less than 5.104 times. To avoid an inadmissible rise in temperature, the maximurr torque shall not occur more frequen
14、tly than twenty times ir succession. TICp ( TKmax) serves to verify the static strength of the coupling it being possible for it to be attained without the couplin( sustaining any damage. Amplitude of the permissible continuous periodic torque fluc. tuations (at a frequency of 10Hz and a base load u
15、p to TKN). Note. In the case of a non-linear coupling characteristic, the operating point shall be specified. Unit Quantity Nominal torque TK N Nm Maximum torque TK m _ TKP Nm Test torque Nm TKW - PKW Nm Fatigue torque Maximum damping pows kW Permissible damping power (applies to ambient temperature
16、5 situated between 10 and 3OoC) Maximum rotational speel min- Maximum permissible rotational speed Moment of inertia 4,2 kg m2 Moment of inertia of the coupling halves (designation of the halves in accordance with the manufacturers data) Permissible axial misalignment of coupling halves Axial misali
17、gnment rnm Radial misalignment mm Permissible radial misalignment of coupling halves Angular misalignment rad Dermissible angular misalignment of coupling halves DIN 740 Part 2 Page 3 Table 1. (continued) Quantity Torsional stiffness static dynamic Axial stiffness static dynamic Radial stiffness sta
18、tic dynamic Angular stiffness static dynamic Damping coefficient Symbol Cr cr dyn CW Cwdyn * Unit N mlrad N mlrad Nlmm Nlrnm Nlmm Nlrnm N mlrad N mirad Definition First derivative of coupling torque with respect to the angle 01 torsion: pis the angle of torsion of one coupling half relative to the o
19、ther Note. As a rule, CTdyn is greater than CT and a function of the stress imposed on the coupling. First derivative of axial restoring force with respect to the axial misalignment: Note. As a rule, Cadyn is greater than Ca. First derivative of radial restoring force with respect to the radial misa
20、lignment: d Fr C, =- d Wr Note. As a rule, Crdy, is greater than C,. First derivative of angular restoring bending moment with respect to the angular misalignment: d MW Cw=- d ww Note. As a rule, C, dyn is greater than C,. Damping parameter 9 = = 2 d Q/cT dyn where AD A,I d SZ CTdyn is the constant
21、dynamic torsional stiffness. is the damping energy during one cycle; is the elastic deformation energy; is the coefficient of damping proportional to velocity; is the angular frequency of harmonic stress imposed on the coupling; A Page 4 DIN 740 Part 2 Table 1. (continued) f, in Hz 110 - No. 16 - -
22、17 - 18 - 19 - 20 - 10 Quantity 2 in h- sz Frequency coefficient 5120 120 240 Please consult manufacturer. 1 ,o 13 Starting coefficient Natural Polyurethane rubber elastomers NR) (PUR) Temperature coefficient Acrylo- nitrile- butadiene- rubber (NW Speed coefficient Resonance coefficient Symbol S“ VR
23、 Unit :oefficient that makes allowance for the additional loading :awed by the frequency of starts, 2, as follows. Zoefficient that makes allowance for the decrease in strength of !lastic rubber materials when exposed to heat. It is of relevance o such materials when used in the immediate surroundin
24、gs of he coupling. This applies, in particular, to the effect of radiant teat, if any. 9 “C -20 TK . Se. Page 6 DIN 740 Part 2 Table 3. Types of stress Type of stress Static stress Harmonic stress Periodic stress Non-periodic stress (including resonance) Non-periodic stress (torque impulse) Stress c
25、haracteristic at the coupling T T c T c T t T t 3.2.2 Stress arising from torque impulses The permissible maximum torque at the coupling shall be at least equal to the torque impulses occurring during operation at all operating temperatures, taking the frequency of the impulses into consideration, i
26、.e. TK niax 2 TS . S, . Se + TN . ,So The permissible maximum torque specified applies to coupling systems with no circumferential backlash. In the case of couplings with circumferential backlash, allowance has already been made for the increased loading resulting from avelocity surge in the nominal
27、 torque of the coupling specified in the catalogue. 3.2.3 Stress arising from periodic alternating torque 3.2.3.1 Traversing the resonance When the resonance below the operational range of the rotational speed is traversed rapidly, only a few resonance peaks occur. The alternating torque in resonanc
28、e can therefore be compared with the maximum torque of the coupling, the follow- ing applying: TK max 2 TS Sz SB + TN . So DIN 740 Part 2 Page 7 2 3.2.3.2 Fatigue torque For the alternating torque, TWi, occurring within the operational range of the rotational speed, the alternating torque of the cou
29、pling, TKw, is to be compared with the frequency corresponding to the ith harmonic, the following applying: TKW rTwi.sl?.sf Nominal output torque 3.2.3.3 Damping heat In lieu of the fatigue torque specified in subclause 3.2.3.2, the damping power may also be compared with the maximum per- missible d
30、amping power, the following applying: PKW 2 PWi s19 3 3.2.4 Stress arising from shaft misalignment Whereas axial misalignment only generates static forces in the coupling, radial and angular displacements produce alternat- ing stresses, their permissible magnitude depending on the speed coefficient.
31、 These stresses can superimpose themselves on the other alternating stresses. The following conditions shall be fulfilled: A Al U m c O m O ._ L c .- c c .- I3 0-J c Q 3 .- - 8 5 a F o) c al .- O c O o 0 al c .- c a n c a al U m O a ._ L c .- c c .- x w U W U m O c O c - E I 1 l i o 0- O QzQ c O Q -
32、1 paads leuo!$e flexible shaft couplings; technical delivery conditions Amann, R.; Kosack, K. Antriebe mit groen schnellaufenden Drehstromrnotoren (Drives with large, high-speed, three-phase motors), Antriebstechnik 1979: 18 (ll), 575-578. Blderl, P.; Kulig, T.; Lambrecht, D. Die Torsionsmomente in
33、Turbinen- und Generatorwellen bei Kurzschlssen, Fehlsynchroni- sierung und Kurzschluabschaltong (Torques in turbine and generator shafts in the event of short circuits,faulty synchroniza- tion and short circuit switching off), ETZ-A, 1975: 96(4), 164-171. Jordan-Engeln, G.; Reutter, F. Numerische Ma
34、thematik fr Ingenieure (Numerical mathematics for engineers) 2nd ed., B-1-Wissenschaftsverlag, 1978. Klingenberg, R. Theoretische Grundlagen herkmmlicher Untersuchungen des dynamischen Verhaltens von Elastomeren (Basic principles of conventional investigations of the dynamic behaviour of elastomers)
35、, VD/-Z, 1981 : 123 (4), 121-126. Klingenberg, R.; Troeder, Chr. Das Resonanzverhalten des nichtlinearen, harmonisch erregten Zweimassenschwingers in Abhngigkeit der Systemparameter (The resonance behaviour of the non-linear, harmonically excited two-mass vibration generating system as a function of
36、 the system parameters), VD/-Z, 1982: 124(14), 539-548. Klotter, K. Technische Schwingungsiehre (Technical vibration theory), Vol. 1 Springer Verlag, 1981: Part A and 1980: Part B. Magnus, K. Schwingungen (Vibrations), 3rd ed., Teubener St., 1976. lonndorf, J. Effect of misfire conditions on the tor
37、sional vibration load of propulsion systems, CIMAC Oslo, 1985. Troeder, Chr.; Peeken, H. Berechnung der instationren Beanspruchungsgren von nichtlinearen und spielbehafteten Maschinenanlagen (Calculation of the non-steady state performance characteristics of non-linear sets of machines subject to ba
38、cklash), Konstruktion, 1976: 28, 129-137. Troeder, Chr.; Peeken, H.; Diekhans, G. Berechnung des stationren und instationren Verhaltens von Antriebssystemen mit Kolbenmaschinen (Calculation of the steady and non-steady behaviour of power transmission systems incorporating recip- rocating engines), V
39、Dl-Bericht, 1980: 381. Previous edition DIN 740 Part 2: 03.75. Amendments The following amendments have been made to the March 1975 edition. a) The scope and field of application of the standard has been precisely defined. b) The standard has been restructured and amended in accordance with the pres
40、ent state of the art; see Explanatory notes. c) The examples of calculation have been supplemented. d) References to relevant literature have been included in the standard, particularly those elucidating higher order calcula- tion methods. e) lhe standard has been editorially revised. Explanatory no
41、tes In the first edition of this standard, published in March 1975, a type of design, largely based on physical laws, was proposed for flexible couplings as a substitute for the specification which, till then, had generally been based on empirical data. In recent years, as the result of new findings
42、 and the close collaboration between various working groups and universities, it became evident that DIN 740 Part 2 had to be revised. It became apparent that the empirical design method should not be neglected and that the design based on physical laws had to be differentiated and supplemented to a
43、 higher degree than before. This means that, in line with contemporary findings, couplings can be designed according to one of the three following methods: a) rough calculation using empirical data provided by the coupling manufacturer; b) rough calculation for a linear two-mass vibrztion generating
44、 system; c) higher order calculation methods, i.e. methods of calculating torsional vibration that permit the solution of differential equations of vibration which are no longer soluble in closed form (simulation methods). For the a) design method, the calculation procedures and coefficients are to
45、be inferred from the coupling manufacturers catalogues. For the b) design method, the formulae given in table 5 may be used. Elaborate calculations in accordance with c) shall be conducted when information has to be obtained on the dynamic stressing behaviour for certain operating conditions, which conventional methods fail to provide. International Patent Classification F 16 D 3/50 G O1 L 3/00 G O1 L 5/00 G O1 B 21/22
