1、UDC 821.85.052.42: 621.85.051 : 629.114 DEUTSCHE NORM February 1986 I Endless narrow V- belts for the automotive industry Dimensions of belts and pulley groove profiles DIN 7753 Part 3 Endlose Schmalkeilriemen fr den Kraftfahrzeugbau; Mae der Riemen und Scheibenrillenprofile Supersedes July 1976 edi
2、tion. In keeping with current practice in standards published by the International Organization for Standardization (Ise), a comma has been used throughout as the decimal marker. See Explanatory notes for connection with International Standard IS0 2790- 1982 published by the International Organizati
3、on for Standardization (ISO). Dimensions in mm 1 Scope and field of application This standard specifies the characteristics of endless narrow V-belts (hereinafter briefly referred to as belts) and the groove profiles of the associated pulleys, used in the automotive industry. The belts are used for
4、driving auxiliaries of internal combustion engines for motor vehicles. Auxiliaries include generators, water pumps, fans, cooling and heating fans, oil pressure pumps, etc. 2 Concepts The pitch width of the belt, b, is the width of the belt at its pitch zone (neutral zone). The width remains unchang
5、ed when the belt is bent perpendicularly to its base. The pitch width of the pulley groove, b, is that width of the pulley groove which is identical to the pitch width of the associated belt. It is not a dimension specific to the groove. The pitch diameter of the pulley groove, d, is the diameter of
6、 the pulley at the pitch width of the pulley groove, b,. The effective width of the pulley groove, bb, is a groove width characterizing the groove profile. It is a defined value not subject to tolerance and is usually located at the outermost extremities of the straight side walls of the groove. For
7、 all belt measuring pulleys and for most machined-type pulleys, it coincides with the actual top width of the groove within reasonable tolerances. The effective diameter of the pulley groove, db, is the diameter of the pulley at the effective width of the pulley groove bb . The effective line differ
8、ential, hb, is the radial displacement between the levels of the pitch width of the pulley groove, b, .e. the position of the pitch width of the belt, and the effective width of the pulley groove bb. Continued on pages 2 to 6 Beuth Verlag Gmbn. Berlin 30. has exclusive sale rights tor German Standar
9、ds (DIN-Normen) DIN 7753 Part 3 Engl. Price group 6 Sales No. 0106 1 1.86 Page 2 DIN 7753 Part 3 Narrow V-belt Type of belt profile 2, 3 Belts 3.1 Dimensions, designation Belt profiles need not conform to the illustration; only the dimensions specified shall be adhered to. The V-belt angle has not b
10、een specif ied . Open-sided 1 Open-sided Full profile Toothed Full profile Toothed Covered Covered 9.5 AVP10 AVX10 12.5 AVP 132) AVX 132) r manufacturers Height h= Effective line differential hb Figure 1. Profile of belt 8 7,5 8 10 8.5 9 18 099 0,g 23 03 0,9 Figure 2. Belt ride-out and effective lin
11、e differential ha Maximum belt ride-out (see figure 2) Designation of a covered narrow V-be t, profile symbol 9,5, of effective length La = 900 mm (900 La): Piarrow V-belt DIN 7753- 9,5 X 900 La Designation of an open-sided toothed narrow V-belt, profile symbol AVX 10, of effective length La = 750 m
12、m (750 La Narrow V-belt DIN 7753 - AVX 10 X 750 La Designation of a set consisting of 2 opim-sided narrow V-belts (2) with full profile, profile symbol AVP 10, of effective length La = 1 O00 mm (1 O00 La) : Narrow V-belt DIN 7753 - 2 X AVP 10 X 1000 La - 24 2-4 2,4 2A - Table 1. Belt dimension Top w
13、idth bo- I 10 I 10 I 10 I 13 I 13 I 13 Effective length La1.5%3) I 500 to 2550: graded in 25 mm steps Permissible difference between the efective lengths of the belts in one and the sane set in the case of multiple-grooved drive,;4) 0,15% ) Open-sided belts may also be fitte,A where previously 9.5 a
14、nd 12,5 type covered belts were required. 2) In ISO, the same symbols, .e. AV 10 and AV 13, are used for all types of a particular belt profile. 3) Other permissible deviations shall be agreed upon separately. 4) Multiple-grooved narrow V-belt di ives require the use of a set of narrow V-belts whose
15、 dimensions are matched to each other. Belts belonging to E set shall be packaged as such or marked to permit identification. If one belt fails, the drive shall be equipped urith a complete new set of narrow V-belts. 3.2 Material, construction, design The materials of belts, construction aiid design
16、 shall be left to the manufacturers discretion, unless otherwise agreed. 3.3 Marking Belts shall be marked on the back with at least the symbol representing the belt profile and the effective length, e.g. 9,5 X 900 La. Additional marking shall be the subject of agreement. DIN 7753 Part 3 Page 3 Type
17、 of groove profile 1 Effective diameter2) db Groove angle3) a f O$ Effective width bb 4 Groove profiles of service pulleys 4.1 Dimensions The design of the groove profile of service pulleys is shown in figure 3; the dimensions are given in table 2. AV 10 AV 13 57 2 57 70 2 70 34O 36“ 34“ 36“ 9.7 12,
18、7 F Minimum depth of pulley groove4) Minimum radius of sides at top of groove t rk e Figure 3. Groove profile of service pulleys 11 14 08 08 Table 2. Groove dimensions of service pulleys Minimum distance between groove centres5) e I 12.6 I 16 1 ) As covered and open-sided belts may run in the same p
19、ulley, only one symbol has been given for the groove profile. 2) The diameter limits given for a groove angle of 34“ may, if necessary, be raised to 70 for AV 10 and 80 for AV 13 3) The axis of symmetry of the groove profile shall form an angle of (90 + 2)O with the pulley axis. 4) The bottom of the
20、 groove may be rounded, provided that the rounding is beneath the nominal depth. 5) These values shall be regarded as recommended values for adjacent groove profiles of the same effective width. groove profiles. Deviations from them are permissible. 4.2 unout tolerance The run-out tolerance (see IS0
21、 1101) of the finished pulley is given in figure 4. a = 2 for belt u = 3 for belt profiles 9.5. AV? 10 and AVX 10 profiles 12,5, AVP 13 and AVX 13 Figure 4. Run-out tolerance II-4 -1 Page 4 DIN 7753 Part 3 4.3 Designation of pulley profiles A standard designation for pulley profiles has not been spe
22、cified as service pulleys are generally designed to suit the requirements of different types of combustion engines and auxiliaries. If a pulley profile designation is requested, it is recom- mended that it be formed as follows. Example: Designation of a pulley profile with an effective diameter of 6
23、7 mm (67). two grooves (2) groove profile type AV 10: Pulley profile DIN 7753 - 67 X 2AV 10 If different grooves are to be included in a pulley, the individual groove profile types shall be given in sequence, as follows: Example: Pulley profile DIN 7753 - 90 X 1 AV 13 - 67 X 1 AV10 5 Testing 5.1 Mea
24、surement of belt length In order to determine the length of the belt, set it up as shown in figure 5 on two identical pulleys of groove shape and dimensions as given in figure 6 and table 3 respect ive1 y. a Figure 5. Measurement device Figure 6. Groove profile of test pulley (material: steel) Apply
25、 to the sliding pulley the measurement force F given in table 3. In order to seat the belt properly in the pulley grooves and to ensure uniform distribution of the measurement force to the two strands, rotate the pulleys with the force applied until the belt has completed at least two revolutions. T
26、hen, measure the centre distance a. Table 3. Dimensions of test pulleys, test rod and measurement force da f 0,2 Outside diameter I of pulley Nominal diameter of test rods ) ds I Distance from external tangent K f 0.05 planes to test rods of pulley groove Effective diameter circumference Measurement
27、 force2) F N AV 10 36“ 95,5 7.94 99.31 11 95,49 300 267 AV 13 36“ 95,5 11.12 103.53 14 95,49 300 267 1 ) Test rod as specified in DIN 2269, accuracy grade 2. 2) The force exerted on each strand of the belt shall be equal to one half of the values shown. The effective length of the belt, La, is to be
28、 calculated from twice the centre distance, a, plus the effective circumference, U, (outside circumference) of the test pulley using the following formula: La = 2a + U, 5.2 Checking of groove angle The check shall be made on the lines of method W as described in the March 1984 edition of DIN 221 1 P
29、art 2. 5.3 Measurement of belt iideout The ride-out of the belt, ha, is to be determined with the belt in the measurement pulley as shown in figure 2. 5.4 Checking of effective diameter of service pulleys Place two test rods (nominal diameter d, accuracy grade 2, as indicated in table 4) as specifie
30、d in DIN 2269 in the grooves to be tested, as shown in figures 7 and 8. Figure 7. Determination of effective diameter of service pulleys DIN 7753 Part 3 Page 5 Nominal diameter of test rod d, Correction factor 2 h, I Figure 8. Arrangement of test rods 7.94 11,12 3,8 8.0 Table 4. Checking of effectiv
31、e diameter I Type of groove profile IAV10/ AV13 I Measure the distance between the external tangent planes parallel to the axis of the pul1ey.K. The effective diameter, db, is then given by The effective diameter of a groove shall be such that distance K does not vary by more than 0,6 mm, when measu
32、red by means of test rods in various radial directions. In the case of multiple-grooved pulleys, determine the dimensions of each groove individually. In a multiple-grooved pulley with grooves of the same nominal dimensions for driving one and the same unit, the difference between the values of dist
33、ance K measured from groove to groove shall not exceed the value given in table 5. db =K - 2 h,. Table 5. Permissible differences in values of K Effective diameter Permissible differences in values of K I Over 150 I 0.3 I Standards referred to DIN 221 1 Part 2 Power transmission elements; grooved pu
34、lleys for narrow V-belts; inspection of grooves DIN 2269 Test rods IS0 1101 Technical drawings; geometrical tolerancing; tolerancing of form, orientation, location and run-out; generalities, definitions, symbols, indications on drawings Other relevant standards DIN 7753 Part 4 Endless narrow V-belts
35、 for the automotive industry; fatigue testing Previous editions DIN 7753: 04.59; DIN 7753 Part 3: 03.67,07.76 Amendments The following amendments have been made in com- parison with the July 1976 edition. a) Open-sided V-belts have been included. b) Dimensions of service pulleys have been included.
36、c) Specifications for testing belts and pulleys have been d) The system of description has been amended. e) A method of measuring the groove angle has been adopted from IS0 2790-1982. included. Page 6 DIN 7753 Part 3 Measurement ball or roller diameters as specified in IS0 2790 Test rod diameters as
37、 specified in DIN 2269, accuracy grade 2 Explantory notes This standard is based on International Standard IS0 2790-1982, Narrow V-belt drives for the auto- motive industry; dimensions. The development of V-belts for the automotive industry has led from the original covered V-belts to the modern ope
38、n-sided V-belts. This has resulted in an upwards dis- placement of the belt in the pulley groove, involving an increase in the pitch width of the belt. The two measures have led to improved performance. The dimensions of both the open-side V-belts and the former covered V-belts have been included in
39、 this standard, whereas IS0 2790 only gives the previously specified dimensions. In supplementing the standard, the system of describing the pulleys and grooves has also been amended by adopting the system which has always been used in the American automotive industry for dimensioning V-belts and, t
40、hus also in the above-mentioned international standard. The basis for the specifications in this descrip- tion system as given in IS0 1081 is not the pitch width of V-belts or the pulley groove, but the top width of the groove. This is called the effective width, w,. Despite the changes made to the
41、description system, the belt design has remained unchanged. Original and modern belts can be used simultaneously for the same belt drive, as far as profile and length are concerned. The term “external length“, however, has been replaced by “effective length“, the symbol La being retained so that no
42、confusion may arise regarding the designation of belts in literature, and when spares are required. Nevertheless, it is recommended to provide modern belts with both the DIN and the IS0 designations as a first step towards replacing national marking with the marking system that has been adopted inte
43、rnationally. As a result of the changeover to the new description system, the previous specifications relating to the pitch 7,950 - 0,025 7.940 i 0.002 1 1.1 24 -:,o25 11,120 f 0,002 Table 6. length and the pitch width have been deleted as they are not essential. However, the location of the pitch w
44、idth of the pulley groove is to be known for deter- mining the pitch diameter, .e. the speed ratio of the belt drive. Therefore, the previous specification relating to the distance of the pitch zone from the back of the belt (previous dimension h,) has been replaced by the effective line differentia
45、l, hb, which is the direct distance between the pitch zone and the top groove width, .e. theeffectivediameter. From this, it is possible to calculate the pitch width of the V-belt, if required. The dimensions of service pulleys have also been included in the standard for the first time. Previously,
46、the only specification applicable was that given in DIN 221 1 Part 1 to the effect that SPZ and SPA grooves are suitable for V-belt drives for the automotive industry. A groove angle (Y of 36O. in standard use throughout the world in the automotive industry, is not specified in DIN 221 1 Part 1, how
47、ever. Therefore, the groove cross sections of the service pulleys specified in IS0 2790 have been adopted, including the dimensions of the pulley grooves. The aim of future development of belt drives is for smaller dimensions whilst retaining the performance, .e. for a smaller pulley diameter, invol
48、ving a reduction in the groove angle. All the specifications on testing belts and pulleys given in clause 5 of this standard have been taken from IS0 2790. The only difference is that, in tables 3 and 4, IS0 speci- fications relating to the diameters of the measurement balls or rollers for testing t
49、he pulley diameters have been replaced by the test rod details given in DIN 2269, the nominal diameters being amended because of different tolerance ranges. A comparison of the measurement ball and roller diameters and the test rod diameters is given in table 6. I Type of belt profile I AV 10 I AV 13 I International Patent Classification F 16 G 5/00 F O2 B 67/06 GO1 B 5/02
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