CONTI SYNCHROBELT HTD Synchronous Drive Belts

Transcription

1 ContiTech Power Transmission Systems CONTI SYNCHROBELT HTD Synchronous Drive Belts ContiTech Division of Continental AG

2 ContiTech Specialist in rubber and plastics technology The ContiTech Division is a development partner and original equipment manufacturer for many branches of industry: with high-grade functional parts, components and systems. It is part of the Continental AG with business units specialising in rubber and plastics technology and utilising their common know-how. That s what the ContiTech brand is all about.

3 CONTI SYNCHROBELT HTD Synchronous Drive Belts 7 Properties Construction 9 Designation 9 1 Available belt range 15/1 Length measurement 17 Tolerances 19 HTD Toothed Pulleys Material Flanged pulleys 1 Designation Pulley diameters 31 Tolerances Balancing Design of Synchronous Belt Drives 3/35 Symbols, units, terms 35 Design data 5 7 Calculation example 7 Power ratings 3 75 Centre distance factors 7 ContiTech drive design service 77/7 Assembly and Storage 79/0 Index

4 1 CONTI SYNCHROBELT HTD Synchronous Drive Belts Properties Construction Designation Available Belt Range Length Measurement Tolerances CONTI SYNCHROBELT HTD Belt Drive in a kale cutting device

5 CONTI SYNCHROBELT HTD Synchronous Drive belts Progress in the Transmission of High Torques: CONTI SYNCHROBELT HTD Synchronous Drive Belts The CONTI SYNCHROBELT HTD synchronous drive belt offers more than a standard toothed belt. Its designation, HTD = High Torque Drive, stands for the transmission of high torques. It features a completely new tooth-profile design as an advancement of the trapezoidal toothed belt, resulting in a uniform transmission of power when the teeth are in mesh, in a better transfer of belt tension to the tension cord, a uni form distribution of stresses within the tooth itself and, thus, in a minimum tooth deformation. With CONTI SYNCHROBELT HTD, synchronous belt drives become more economical, safer, and they render possible a synchronous transmission equivalent to chain and gear drives. The CONTI SYNCHROBELT HTD synchronous drive belt stands for progress, advanced technology and economy. Its field of application is continuously growing: application areas include tool manufacture, machine, motor and engine construction: printing, textile and paper making machines: printers, copying and office machinery: electric tools and household appliances

6 CONTI SYNCHROBELT HTD Synchronous Drive Belts 1 Stress Distribution in Synchronous Drive Belts with Standard and CONTI SYNCHROBELT HTD Tooth Profile Trapezoidal profile Tension Cord Synchronous drive belt Tension Cord Synchronous drive belt CONTI SYNCHROBELT HTD tooth profile Load 3 Stress distribution in the trapezoidal tooth Load distribution across the tooth Load distribution across the tooth Load Stress distribution in the CONTI SYNCHROBELT HTD tooth

7 1 1 1 CONTI SYNCHROBELT HTD Synchronous Drive belts CONTI SYNCHROBELT HTD Synchronous Drive Belts offer the following advantages: Positive Drive System Without Slippage In the same way as with a gear drive, the belt s teeth mesh with the toothing of the drive pulleys. The special tooth profile of belt and pulleys guarantees a precise synchronism and a high degree of safety against tooth jump High Power Output The rounded HTD tooth profile combined with the wear resistant facing fabric as well as with the high dynamic load-bearing capacity of the tension cord ensures operating efficiency HTD synchronous drive belts render possible a positive transmission of power for high torques in such fields of application where only chain drives or gears drives have been made use of to date. Minimum Space Requirements The high power output renders possible the design of heavy-duty drives with compact construction and a low weight. Extensive Speed Range The high strength of the belt teeth as well as the excellent flexibility of the synchronous drive belts render possible operationally safe and reliable drive versions in the lower speed range and at belt speeds up to m/s. 7

8 Low Synchronous Drive Belt Tension The positive transmission of power requires only low initial tensioning. The HTD tooth profile guarantees a high degree of safety against tooth jump. So the axle and bearing loads stay low. No Lubrication and Maintenance CONTI SYNCHROBELT HTD synchronous drive belts are free from maintenance: no lubrication and retensioning required. HTD synchronous drive belts are insensitive to corrosion and stable in length. Low-Noise Running The flexible synchronous drive belt construction, the frictionless meshing of the teeth and the combination of fabric-faced rubber teeth with toothed pulleys of metal or of synthetic material reduce the running noise to a minimum. High Efficiency CONTI SYNCHROBELT HTD Synchronous Drive Belts 1 The flexible synchronous drive belt construction as well as the exact dimensional match of the tooth profile of the belts and pulleys allow drives with an efficiency of 9%. CONTI SYNCHROBELT HTD synchronous drive belts of the standard version are oil resistant to a degree tropics-resistant remain stable over a temperature range from C to 0 C according to application ozone-resistant insensitive to weathering

9 1 CONTI SYNCHROBELT HTD Synchronous Drive belts Construction Polychloroprene-belt top Glass tension cords Polychloroprene teeth Polyamide fabric These are the components of the synchronous drive belt: Teeth and belt top of polychloroprene Polyamide fabric (facing fabric) Glass tension cords. Teeth and Belt Top of Polychloroprene The teeth and the belt top are made from highly loadable polychloroprene based elastomer materials. A special manufacturing process ensures an excellent adhesion both on the tensile member and on the facing fabric. Polyamide Fabric A durable protection of the teeth is an essential precondition for a smooth operation and a long service life. This is ensured by the application of particularly abrasion-resistant polyamide fabrics with low friction coefficients. Glass Tension Cords Synchronous belt drives call for a high degree of length stability and tensile strength. These requirements are optimally met by low-elongation tensile members of glass cord helically wound over the entire belt width. Any longitudinal off-track running will be largely prevented by the use of tensile cords twined in reversed lay in pairs. Further design features: High resistance to fatigue failure Temperature and ageing-resistant High resistance to tearing

10 Designation CONTI SYNCHROBELT HTD synchronous drive belts are designated by the following data: Pitch length in mm The pitch length of the synchronous drive belt is the overall circumference measured on the neutral pitch line. The pitch length is located in the middle of the tensile member. The precise pitch length can only be ascertained on suitable measuring devices. See section Length Measurement (page 15) for further information. Tooth pitch in mm The tooth pitch is the linear distance between two adjacent teeth along the pitch line. Synchronous drive belt width in mm The synchronous drive belt width and the width designation are identical. Example CONTI SYNCHROBELT HTD synchronous drive belt 9 M 9 9 mm pitch length M mm tooth pitch mm synchronous drive belt width The number of teeth z is a function of pitch length and pitch: z L w t Available Belt Range CONTI SYNCHROBELT HTD synchronous drive belts are made use of in the entire drive technology sector, from the field of precision mechanics to the construction of heavy machinery. A comprehensive standard programme has been established for all these loads and conditions of application. CONTI SYNCHROBELT HTD synchronous drive belts are supplied in 5 tooth pitch versions: HTD 3M: HTD 5M: HTD M: HTD 1M: CONTI SYNCHROBELT HTD Synchronous Drive Belts 1 3 mm tooth pitch 5 mm tooth pitch mm tooth pitch 1 mm tooth pitch The length and width dimensions that can be supplied are shown in the tables 1 5 (pages 1)

11 1 CONTI SYNCHROBELT HTD Synchronous Drive Belts Tooth Profile HTD 3M *Non-stock items, delivery on request. Standard widths:, 9, 15 mm; intermediate widths on request. 1.. Standard lengths Table 1 Designation Pitch length L W (mm) No. of teeth z 111 3M M* M M* M 1 1 3M M* M M M M M* 1 3M* M* M 1 7 3M* 3M 13 3M M 1 5 3M M 0 3M* 3M 55 3M M M* M* M M M M M M M M M M M M 0 1 3M* 9 3M* M* M M M* M*

12 CONTI SYNCHROBELT HTD Synchronous Drive Belts 1 Tooth Profile HTD 3M Standard lengths Table 1 Designation Pitch length L W (mm) No. of teeth z 537 3M M M M* M* 0 3M 3M* 33 3M M 9 3 3M M M* M* M 7 3 3M* 3 1 3M M M* M M M M M* M M *Non-stock items, delivery on request. Standard widths:, 9, 15 mm; intermediate widths on request

13 1 CONTI SYNCHROBELT HTD Synchronous Drive Belts Tooth Profile HTD 5M Standard lengths Table Designation Pitch length L W (mm) No. of teeth z 5 5M* M* M M* M 0 3 5M 3 3 5M M M M 5 5 5M 90 5M M M M* M M M M M M 5M 35 5M M M M M M M M M M M M M M 15 5M M 10 5M 5 1 5M M M *Non-stock items, delivery on request. Standard widths: 9, 15, 5 mm; intermediate widths on request. 7

14 CONTI SYNCHROBELT HTD Synchronous Drive Belts 1 Tooth Profile HTD M Standard lengths Table 3 Designation Pitch length L W (mm) No. of teeth z M 3 3 M 3 37 M M 1 M 53 M* M 0 5 M 5 0 M 0 75 M* 7 M 0 5 M 5 7 M M* M M M M* M M M M M M M M* M 13 1 M M M M 17 0 M M 00 M 1 0 M M M 0 37 M M 77 *Non-stock items, delivery on request. Standard widths:,,, 5 mm; intermediate widths on request

15 1 CONTI SYNCHROBELT HTD Synchronous Drive Belts Tooth Profile HTD 1M Standard lengths Table Designation Pitch length L W (mm) No. of teeth z 9 1M M M M M M M 1 3 1M M M M M M M M M Standard widths: 0, 55, 5, 115, 1 mm; intermediate widths on request

16 Length Measurement CONTI SYNCHROBELT HTD Synchronous Drive Belts 1 The pitch length is decisive for the calculation and application of CONTI SYNCHROBELT HTD synchronous drive belts. A precise measurement can only be made on suitable measuring equipment. The synchronous drive belt is placed over two equal size measuring pulleys with the same pitch diameters. The movable measuring pulley is loaded in such a way that the measuring force F will act on the synchronous drive belt. To ensure a correct position of the synchronous drive belt on the pulleys and a uniform tension on both belt sides, the synchronous drive belt must have completed at least rotations under load. The centre distance a is then to be measured between the two pulleys. The pitch length L W is double the centre distance a plus the pitch circumference U W of the synchronous drive belt test pulleys. L W a U W a d W a z t The test measurement lay-out is shown in Fig. 1. The dimensions of the measuring pulleys and the measuring forces are indicated in table Meßkraft F 3 3 Achsabstand a Measuring configuration Fig

17 CONTI SYNCHROBELT HTD Synchronous Drive Belts Measuring Pulleys and Test Force Table 5 Tooth profile HTD 3M HTD 5M HTD M HTD 1M Tooth pitch t mm No. of teeth z Pitch diameter d w mm Pitch circumference U w mm Outside diameter d a mm Measuring force F N mm 0 for width b 9 mm 1 15 mm 1 mm 0 5* 5 mm mm * 0 mm * *For synchronous drive belts with a larger width, length measurement is performed on narrower belts at a correspondingly reduced measuring force

18 Tolerances Pitch length L W mm CONTI SYNCHROBELT HTD Synchronous Drive Belts 1 CONTI SYNCHROBELT HTD synchronous drive belts are precision products. They are manufactured with maximum care and accuracy. The tolerances for length, width and thickness variations are extremely narrow. Length Tolerances for Synchronous Drive Belts Table For further information on length measurement, see page 15. Tolerance of centre distance deviation mm The tolerance value increases by a further 0.05 mm per 0 mm increase in length. Width Tolerances for Synchronous Drive Belts Table 7 Belt width b Width tolerance for pitch length L W mm up to up to 17 mm mm mm mm Thickness Tolerances for Synchronous Drive Belts Table Tooth profile HTD 3M HTD 5M HTD M HTD 1M Belt thickness h s mm Thickness tolerance Standard constuction mm Thickness tolerance Special construction mm

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20 Material Flanged Pulleys Designation Pulley Diameters Tolerances Balancing HTD Toothed Pulleys CONTI SYNCHROBELT HTD synchronous drive belt on a machine tool. 7

21 HTD Toothed Pulleys HTD Toothed Pulleys The function of a synchronous belt drive is essentially influenced by the quality of the pertaining toothed pulleys. They are precision components and produced with milling cutters accurately to pitch so that a precise meshing of teeth is obtained. Toothed pulleys for SYNCHROBELT HTD synchronous belt drives are manufactured to customers specifications. ContiTech s application engineers can put you in touch with experienced manufacturers. Material The material selected depends on the size of the pulley and on the power to be transmitted. Plastic PA and., POM for tooth pitches 3 and 5 mm Aluminium alloy AlCuMgPb F 35 to F 3 for tooth pitches 3 and 5 mm, in hard anodised type possibly also for tooth pitch mm Steel 9 SMn K, 9 SMnPb K, Ck5 for tooth pitches 5, and 1 mm Grey cast iron GG- to GG-5 for tooth pitches and 1 mm When placing orders without any particular specification, the respective material will be seleted as dictated as by practical experience. Flanged Pulleys Flanged pulleys prevent synchronous drive belts from tracking off. It is necessary to provide at least one toothed pulley with side flanges. This is normally the smaller toothed pulley for reasons of cost. It is also possible to incorporate a single sided flange on each pulley. In the case of drives with a centre distance of a d wk, both toothed pulleys are required to be equipped with pulleys flanged on both sides. Flanged pulleys are angled at the discretion of the pulley manufacturers and/or they are chamfered or radiused. They are generally screwed on for pulley diameters of mm. For diameters mm, flanged pulleys are screwed on as from pulley width of 5 mm; with all other pulleys, flanged pulleys are generally press-fit. For drives with a fixed centre distance, screwed-on flanged pulleys should be provided for ease of mounting. The height of the flanged pulley shall at least be identical with the height of the synchronous drive belt running in the pulley. The tolerance for the outside diameter of the flanged pulley amounts to 1.0 mm. The thickness of the flanged pulley is governed by the outside diameter of the toothed pulley. Flanged Pulley Thickness s b in mm Table 9 Tooth profile HTD 3M HTD 5M HTD M HTD 1M Toothed pulley- Outside diameter d a mm

22 Designation HTD toothed pulleys are designated as follows: P General designation for toothed pulleys. No. of teeth HTD Toothed Pulleys The number of teeth of the toothed pulley is calculated from the pitch circumference and the pitch: z U w t d w t Tooth pitch in mm The tooth pitch of the pulley is the distance between two reference points on adjacent teeth at the pitch circumference. The pulley pitch diameter is larger than the outside diameter of the pulley by double the thickness at which the pitch line of belt rides above the pulley. Toothed pulley width in mm The width designation defines the exact width of the pertaining synchronous drive belt, but not the exact pulley width. Tables to 1 indicate the interrelationship of the synchronous drive belt and of the pulley width (pages 3 to ). Flanged pulley data F means pulleys flanged on both sides. Example HTD toothed pulley PT 0 M F PT Designation for the toothed pulley with Taper Look bush 0 0 teeth M mm tooth pitch Toothed pulley designation for a mm wide synchronous F Pulleys flanged on both sides When placing orders, comprehensive data and instructions will help avoid misunderstandings and delay. The data given under toothed pulley specification index facilitates compilation of all values required. It furthermore contains instructions on which pages the exact data can be found

23 HTD Toothed Pulleys Toothed Pulley Specification Index Table Parameter Toothed Pulley Toothed Pulley Page reference pulley pitch 1 3M 5M M 1M Tooth pitch t mm 3 5 No. of teeth z 3 5 Pitch diameter d w mm 3 5 Outside diameter d a mm 3 5 Width designation mm 3 5 Effective pulley width mm 3 5 Flanged pulleys on side/on both sides on side/on both sides Flanged pulleys diameter d b mm Flanged pulleys thickness S b mm Type of mounting* pressed/screwed on pressed/screwed on Stock bore d v mm 3 5 Finished bore d F mm 3 5 Fit Keyway Material Special features** 31 * Pressed = fixed, screwed = detachable, e.g. for fixed centre distance ** e.g. narrow Tolerances, balancing, clamping bushes, hub, surface treatment Pulley Diameters Tables 11 to 17 (pages 3 to ) indicate preferred sizes for SYNCHROBELT HTD toothed pulleys. Further sizes can be supplied for drives requiring toothed pulleys with different numbers of teeth. For these sizes, tables 19 to (pages 7 to ) contain data on the numbers of teeth and on the outside and pitch diameters. Further information about the flanged pulley diameter, stock bore and maximum finished bore on request

24 HTD Toothed Pulleys Tooth Pitch 3 mm Preferred Sizes HTD Toothed Pulleys (Dimensions in mm) Table 11 No. of Pitch-Ø Outside-Ø Flanged Stock Finished teeth pulley-ø bore-ø bore-ø z d w d a d b d v d F max Interrelation Synchronous Drive Belt Width Pulley Width for Standard Belt Widths (Dimensions in mm) Table Synchronous drive belt width b Toothed pulley; face width for flanged pulleys with flanges without flanges The toothed width of pulleys with flanges may vary slightly, as the thickness of the depends on the diameter of the pulley (Table 9, page )

25 HTD Toothed Pulleys HTD Toothed Pulleys Tooth Pitch 5 mm Preferred Sizes (Dimensions in mm) Table 13 No. of Pitch-Ø Outside-Ø Flanged Stock Finished teeth pulley-ø bore-ø bore-ø z d w d a d b d v d F max Interrelation Synchronous Drive Belt Width Pulley Width for Standard Belt Widths (Dimensions in mm) Table 1 Synchronous drive belt width b Toothed pulley; face width for flanged pulleys with flanges without flanges The toothed width of pulleys with flanges may vary slightly, as the thickness of the depends on the diameter of the pulley (Table 9, page )

26 HTD Toothed Pulleys Tooth Pitch mm Preferred Sizes HTD Toothed Pulleys (Dimensions in mm) Table 15 No. of Pitch-Ø Outside-Ø Flanged Stock Finished teeth pulley-ø bore-ø bore-ø z d w d a d b d v d F max _ _ Interrelation Synchronous Drive Belt Width Pulley Width for Standard Belt Widths (Dimensions in mm) Table 1 Synchronous drive belt width b Toothed pulley; face width for flanged pulleys with flanges without flanges The toothed width of pulleys with flanges may vary slightly, as the thickness of the depends on the diameter of the pulley (Table 9, page )

27 HTD Toothed Pulleys HTD Toothed Pulleys Tooth Pitch 1 mm Preferred Sizes (Dimensions in mm) Table 17 No. of Pitch-Ø Outside-Ø Flanged Stock Finished teeth pulley-ø bore-ø bore-ø z d w d a d b d v d F max Interrelation Synchronous Drive Belt Width Pulley Width for Standard Belt Widths (Dimensions in mm) Tabelle 1 Synchronous drive belt width b Toothed pulley; face width for flanged pulleys with flanges without flanges The toothed width of pulleys with flanges may vary slightly, as the thickness of the depends on the diameter of the pulley (Table 9, page ). 7

28 HTD Toothed Pulleys Tooth Pitch 3 mm HTD Toothed Pulleys (Dimensions in mm) Table 19 No. of Outteeth Pitch-Ø side-ø z d w d a No. of Outteeth Pitch-Ø side-ø z d w d a No. of Outteeth Pitch-Ø side-ø z d w d a No. of Outteeth Pitch-Ø side-ø z d w d a

29 HTD Toothed Pulleys HTD Toothed Pulleys Tooth Pitch 5 mm (Dimensions in mm) Table No. of Outteeth Pitch-Ø side-ø z d w d a No. of Outteeth Pitch-Ø side-ø z d w d a No. of Outteeth Pitch-Ø side-ø z d w d a No. of Outteeth Pitch-Ø side-ø z d w d a

30 HTD Toothed Pulleys Tooth Pitch mm HTD Toothed Pulleys (Dimensions in mm) Table 1 No. of Outteeth Pitch-Ø side-ø z d w d a No. of Outteeth Pitch-Ø side-ø z d w d a No. of Outteeth Pitch-Ø side-ø z d w d a No. of Outteeth Pitch-Ø side-ø z d w d a

31 HTD Toothed Pulleys HTD Toothed Pulleys Tooth Pitch 1 mm (Dimensions in mm) Table No. of Outteeth Pitch-Ø side-ø z d w d a No. of Outteeth Pitch-Ø side-ø z d w d a No. of Outteeth Pitch-Ø side-ø z d w d a No. of Outteeth Pitch-Ø side-ø z d w d a

32 Tolerances Outside Diameter, Axial and Radial Runout Tables 3 to 5 feature the tolerances for outside diameter, axial and radial runout. Outside Diameter Tolerance Table 3 Outside diameter d a mm Tolerance mm Axial Runout Tolerance Table Outside diameter d a mm Tolerance mm per mm outside diameter per mm outside diameter Outside diameter d a mm Tolerance mm HTD Toothed Pulleys Radial Runout Tolerance Table per mm outside diameter Parallelism Parallelism between the bore and teeth may not exceed the maximum deviation of 1 m per millimeter of toothed pulley width. Taper The taper may amount to a maximum of 1 m per millimeter over the width of the tooth and, at the same time, must not exceed the permissible diameter tolerance

33 HTD Toothed Pulleys Balancing With toothed pulleys machined on all sides, balancing is normally not necessary up to a circumferential speed of m/s. Cast iron pulleys, however, must also be balanced at v m/s. In general, there applies the following: Static balancing quality level Q 1 as per VDI at v m/s for d w 00 mm or at n 10 min 1 for d w 00 mm. Dynamic balancing as per recommended practice Q.3 at v m/s or at v m/s at a pitch diameter to toothed pulley width ratio of. Balancing takes place with non-keyed toothed pulleys on a smooth balancing mandrel. For further details, see ISO 5 and VDI Recommendation. Balancing is performed on special request only

34 3 Design of Synchronous Belt Drives Symbols, Units, Terms Design Data Calculation Example Power Ratings Centre Distance Factors ContiTech Drive Design Service CONTI SYNCHROBELT HTD synchronous drive belt being fatigue and performance-tested 7

35 3 Design of Synchronous Belt Drives 1 1 Design of Synchronous Belt Drives The following drive design is based upon drives equipped with CONTI SYNCHROBELT HTD synchronous drive belts 3M, 5M, M and 1M. In the event of particularly critical drive problems and multi-pulley applications, we recommend to contact ContiTech s application engineers for a noncommital consultation. 1 d ag d wg d ak d wk F v a Symbols, Units, Terms Symbol Unit Term a mm Centre distance b mm Width of synchronous drive belt c Overall service factor c Teeth in mesh factor c Load factor c Acceleration factor c Fatigue factor c Length factor d a mm Outside diameter of toothed pulley d ag mm Outside diameter of large toothed pulley d ak mm Outside diameter of small toothed pulley d w mm Pitch diameter of toothed pulley d w mm Pitch diameter of driving toothed pulley d w mm Pitch diameter of driven toothed pulley d wg mm Pitch diameter of large toothed pulley d wk mm Pitch diameter of small toothed pulley f Hz Natural frequency F e N Test force F stat N Static belt tension F v N Overall preload i Speed ratio L w mm Pitch length of synchronous drive belt n min Speed of driving toothed pulley n min Speed of driven toothed pulley n g min Speed of large toothed pulley n k min Speed of small toothed pulley P kw Power to be transmitted P R kw Power rating for standard belt width 3 7

36 Symbol Unit Term t mm Tooth pitch v m/s Belt speed z mm No. of teeth of the synchronous drive belt z mm No. of teeth of driving toothed pulley z mm No. of teeth of driven toothed pulley z g mm No. of teeth of large toothed pulley z k mm No. of teeth of small toothed pulley (degree) Belt side inclination angle (degree) Wrap angle on the small toothed pulley Design Data The design data contains all data, formulae and tables required for the calculation of CONTI SYNCHROBELT HTD synchronous belt drives. Omitted from the tables are values which can be easily calculated with the aid of the formulae specified. Overall Service Factor c 0 The overall service factor c 0 takes into consideration safety factors for special operating conditions caused by loading conditions, acceleration and fatigue. It is calculated on the basis of the following factors: c 0 = c + c 3 + c Teeth in Mesh Factor c 1 The teeth in mesh factor c 1 considers the number of teeth z e of the small toothed pulley z k meshing with the teeth of the synchronous drive belt. z e = z k 3 The calculation of the wrap angle is illustrated on page 0. Design fo Synchronous Belt Drives The values for z e are indicated in the table. No. of meshing teeth z e Teeth in mesh factor c Table

37 3 Design of Synchronous Belt Drives Load Factor c The load factor c considers the type of the prime mover and of the driven machine. Particular conditions of operation are not considered in these values. The factors indicated are reference values. Load Factor c Table 7 Prime Movers Electric motors with a Electric motors with a Electric motors with a slow starting torque medium starting torque high starting torque (up to 1.5 times the rated (1.5 to.5 times the rated and braking torque torque) torque) (more than.5 times Water and steam turbines Internal combustion the rated torque) Internal combustion - engines with Internal combustion engines with to cylinders engines Driven machines and more cylinders up to cylinders Office machines Typewriters Printers, scanners, teleprinters, photocopiers Small machines Motion-picture projectors and cameras Domestic machines Centrifuges Kitchen machines, universal cutters Sewing machines Domestic sewing machines Industrial sewing machines Laundry machines Driers Washing machines Conveyor Systems Belt conveyors for light material Belt conveyors for ore, coal, sand for heavy materials Elevators, screw conveyors, bucket-type elev Stirrers Mixers, liquid semiliquid Bakery machines Bakery and dough-working machines Machine tools Lathes Machines for drilling, grinding, milling, planning Wood working- Wood turning lathes and band saws machines Planning machines and circular saws Sawing-mill machines Brickworks machinery Milling machines Loam mills Textile machinery Bobbin winding and warping machines Machines for spinning, twisting and weaving Paper making Agitators, calenders, drying machines machines Pumps, beating machines, stuff grinders Printing machines Cutting, slitting and folding machines Rotary presses Screen machines Drum screens Vibration screens Fans, blowers Exhausters, radial blowers Pit ventilators, axial blowers Compressors Helical compressors Piston compressors Pumps Centrifugal and and gear pumps Reciprocating pumps Generators Generators and exiters Elevators Elevators and hoists Centrifuges Processing machines Rubber processing machines Mills Hammer mills Ball, roller and gravel mills

38 Design fo Synchronous Belt Drives 3 CONTI SYNCHROBELT HTD Synchronous Drive Belt Acceleration Factor c 3 The acceleration factor c 3 is to be applied when the step-up transmission ratio is 1.. Transmission ratio 1 Acceleration factor c 3 i Type and period of operation Fatigue factor c Daily period of operation 1 hours 0. Daily period of operation over 1 hours 0. Additional belt deflection, 0. e.g. by means of tensioning rolls Intermittend operation 0. Table Fatigue Factor c The fatigue factor c takes into consideration the daily period of operation and the particular operating conditions. Length Factor c 5 The length factor c 5 takes into consideration the belt flexing frequency as a function of the synchronous drive belt pitch length L W. Table 9 Length Factor c 5 Table 3M Pitch length L W mm to 1 to to 0 0 c M Pitch length L W mm 1 1 to 0 1 to to c M Pitch length L W mm to to 79 1 to c M Pitch length L W mm to to 99 to to c

39 Design of Synchronous Belt Drives Selection of the Synchronous Drive Belt Pitch The diagrams of Figs. and 3 render possible selection of the suitable synchronous drive belt pitch in accordance with the power to be transmitted by the synchronous belt drive, corrected by the overall service factor c 0 and by the speed of the small toothed pulley. CONTI SYNCHROBELT HTD Synchronous Drive Belt 3M, 5M Fig. Speed of small pulley n k r.p.m M 3M / 5M 5M P c 0 (kw) 3 7

40 Where the table offers two pitch alternatives, it is recommended to calculate the drive in connection with both pitches. An optimum utilization of power is obtained by the selection of pulley diameters being as large as possible. CONTI SYNCHROBELT HTD Synchronous Drive Belt M, 1M Fig. 3 Speed of small pulley n k r.p.m Design fo Synchronous Belt Drives M M / 1M 1M P c 0 (kw) 39 7

41 3 Design of Synchronous Belt Drives Permissible effective pull F u zul The permissible effective pull F u zul in N is shown in Table 31. Permissible effective pull in N Table 31 Belt width Tooth profile mm 3M 5M M 1M Transmission Ratio i The transmission ratio i results from the ratio of the toothed pulley speeds n 1 and n and/or of the number of teeth z and z 1 or the pitch diameters of the toothed pulley d w and d w1 : n 1 n z z 1 i No. of teeth and Pitch Diameter d w of the Toothed Pulleys The number of teeth z and the pitch diameter d w of the toothed pulleys are determined by means of pitch t of the tooth profile selected: d z g wg z d wg g t mm t d z k wk z d wk k t mm t The number of teeth, pitch diameter and outside diameter for toothed pulleys are indicated in the tables 11 to (pages 3 to ). Wrap Angle This is the angle of contact around the small pulley: arccos d w d w1 t (z g z k ) a (degree) 0 7

42 Design fo Synchronous Belt Drives 3 Centre Distance a The centre distance a is calculated on the basis of the following approximation: 1 a L w (z g z k ) L w (z g z k ) (z g z k ) mm The following guidelines apply to the determination of the centre distance for new and/or revised designs. 0. t (z g z k ) a 0.7 t (z g z k ) mm Calculation of the precise centre distance at a given synchronous drive belt length is possible on the basis of a very simple method with aid of table (page 3 onwards). Example t The table applies to all synchronous drive belts indicated in this publication and to transmission ratios not equal to 1. With a transmission ratio of i 1, the centre distance can be determined on the basis of the following formula: L a w d w t mm or a (z z 1 ) mm In cases where the tabular values are insufficient, the centre distance can be approximately determined by means of the above formula. t t Given: CONTl SYNCHROBELT HTD Synchronous Drive Belt 9 M z = 1 teeth HTD Toothed Pulley PT5 M z g = 5 teeth HTD Toothed Pulley PT0 M z k = 0 teeth 1. Difference between the number of teeth of the synchronous drive belt and the number of teeth of the small toothed pulley z z k 1 0 = 0. Difference between the number of teeth of the large and of the small toothed pulley z g z k 5 0 = 1 3. Centre distance factor at the point of intersection of column z z k and line z g z k (page 7) Product of the centre distance factor and pitch in mm of the selected tooth profile Centre distance factor t 35.3 = 3.0 mm The calculated value is the exact centre distance a in mm

43 3 Design of Synchronous Belt Drives Pitch Length L w The pitch length L w of the synchronous drive belt is approximated to a drive with two pulleys: t (z g z k ) L w a t (z g z k ) mm a and here the precise calculation: t L w a sin z g z k 1 (z g z k ) mm Calculation of the exact synchronous drive belt length at a given centre distance is possible by means of a very simple method with the aid of table (page 3 onwards). Example Given: HTD Toothed Pulley PT5 M z g 5 teeth HTD Toothed Pulley PT0 M z k 0 teeth Given centre distance a a 0 mm 1. Difference between the number of teeth of the large toothed pulley and the number of teeth of small toothed pulley z g z k 5 0 = 1. Quotient from the centre distance in mm and the pitch in mm of the selected tooth profile a t nearest centre distance factor on the line z g z k (page 7) Corresponding difference between the number of teeth of the synchronous drive belt and the number of teeth of the toothed pulley z z k obtained from the table 5. Sum of this value and of the number of teeth of the small pulley (z z k ) z k 0. Product of the number of teeth of the synchronous drive belt and of the selected pitch in mm z t 99 mm The exact synchronous drive belt pitch length L w in mm is the calculated value. To avoid special sizes, please consider the application of CONTl SYNCHROBELT HTD synchronous drive belts of the nearest standard length (see Table 3, page 13), e.g. by means of changing the centre distance. Recommendation: CONTl SYNCHROBELT HTD Synchronous Drive Belt 9 M with 1 teeth Centre distance a 3.0 mm 0 7

44 Design fo Synchronous Belt Drives 3 Belt Speed v The belt speed v is a function of pitch t in mm, number of teeth z k and speed n k in min 1 of the small toothed pulley: v t z k n k 3 m/s Synchronous Drive Belt Width b The synchronous drive belt width b in mm results from the power P to be transmitted, corrected by the overall service factor c 0, and the power rating P R, corrected by the teeth in mesh factor c 1 and the length factor c 5. The following applies to a standard belt width: If P c 0 P R c 1 c 5 P c 0 P R c 1 c 5 the next larger standard width should be applied. To obtain a synchronous drive belt width as narrow as possible, the toothed pulleys should be selected as large as possible. This will result in a longer service life at a lower bending load. Synchronous Drive Belt Tension F v The overall tension F v is a decisive factor for the efficiency and length of service life of a synchronous belt drive. The following recommendation is given: F v P sin _ t z k n k N 3 0 The static belt side force F is a function of the overall tension F v and of the wrap angle ß on the small toothed pulley: F stat F v N sin

45 Design of Synchronous Belt Drives L f t e L f F e Belt deflection t e Fig. 5 Checking the initial tension a. Flexing method The correct setting of the required initial tension F v can be checked using Fig.. The calculation on page 5 gives explanatory notes on this. Effective pull F u F e Test force in N t e Belt deflection in mm L f Free span length in mm t e L f 00 Characteristic value of initial tension Characteristic lines of initial tension The test force F e in N is calculated from the synchronous drive belt width b in mm, an allowance and a factor for the individual profiles as follows: Toothed profile 3M: F e b 15 Toothed profile 5M: F e. b 15 Toothed profile M: F e b Toothed profile 1M: F e b 5 t Characteristic value of initial tension e 00 L f Fig. b. Frequency measuring method In this method, the initial tension is obtained by measuring the natural frequency of the part of the belt that is set vibrating. F stat m L f f N m Synchronous drive belt weight in kg/m L f Free span length in mm f Natural frequency in Hz The specific belt weights m s of CONTl SYNCHROBELT HTD Synchronous Drive Belts are shown in table below Specific belt weights m s Table Synchronous drive belt profile HTD 3M HTD 5M HTD M HTD 1M m s kg/m per mm belt width Power Rating P R Tables 33 to 7 (pages to ) indicate the power rating P R for CONTI SYNCHROBELT HTD synchronous drive belts in kw as a function of the number of teeth z k and/or of the pitch diameter of the small pulley d wk and of the speed of the small toothed pulley n k. A table has been made up for each standard width. 7

46 Load factor c from Table 7, page 3 c 1. Acceleration Factor c 3 from Table, page 37 c 3 0 Fatigue Factor c from Table 9, page 37 c 0. Overall Service Factor Calculation Example Prime mover: Electric motor P 5 kw with mean starting torque n 1 1 min 1 Driving machine: Lathe n 00 min 1 % Operating conditions: Diameter of large toothed pulley 1 mm Centre distance 0 mm Daily period of operation 1 hrs c 0 c c 3 c c Selection of Synchronous Drive Belt Pitch Diagram Fig. 3, page 39 Speed Ratio n 1 z 1 i i 1.5 n z 1 00 No. of Teeth and Pitch Diameter of the Toothed Pulleys Condition: d wg 1 mm z g from Table 1, page 9 Selected: z z g z g 5 d wg 17. mm z g 5 z 1 z k z k 0 i 1.5 d wk from Table 15, page 5 d wk 1. mm Selected: CONTI SYNCHROBELT HTD Synchronous Drive Belt M t mm Pitch Length t_ (z g z k ) _ (5 0) t L w a (z g z k ) L w 0 (5 0) 99 mm a 0 Determination of the Pitch Length that can be supplied L w from Table 3, page 13 L w 9 mm z 1 Design fo Synchronous Belt Drives

47 Design of Synchronous Belt Drives Centre distance a from Table, page. z z k z g z k Centre distance factor from Table, page a centre distance factor t a mm Belt Speed t z k n k 0 1 v v 7.73 m/s 3 3 Wrap Angle on the Small Toothed Pulley arccos t (z g z k ) arccos (5 0) 1.71 Teeth in mesh Factor 1.71 z e z k z e c 1 from Table, page 35 c Length Factor a c 5 from Table, page 37 c Synchronous Drive Belt Width Requirement P c 0 P R c 1 c 5 P c 0 P R c 1 c 5 P R from Table 39, page kw kw P R. kw for a synchronous drive belt width of mm kw. kw Requirement for a mm wide synchronous drive belt Layout: 1 CONTI SYNCHROBELT HTD synchronous drive belt 9 M 1 HTD toothed pulley PT0 M F 1 HTD toothed pulley PT5 M Synchronous Drive Belt Tension Overall tension 1.71 P sin _ 5 sin F v F v.3 N t z k n k 0 1 7

48 Checking the initial tension a. Flexing method Test force for pitch mm, see page F e b + F e + 0 N Effective pull F u P F u F u 5.55 N t z k n k 0 1 Belt tension parameter for F u and pitch mm from diagram Fig. page t e L f Free span length 1.71 L f a sin L f 3.0 sin mm Belt deflection L t e f belt tension parameter t e mm b. Frequency measuring method Explanations: see page m s specific weight of synchronous drive belt m s 5. 3 kg/m mm per m length and mm width for Table, page b width of synchronous drive belt m weight of synchronous drive belt per m length Given the test force is 0 N and the deflection is.3 mm, the synchronous drive is properly tensioned for use. F e + 0 N m m s b m kg/m L f free span length L f mm Calculation: see point a. Flexing method F stat predefined static belt tension Calculation: see page 3 the desired frequency derived from above F stat 3. N 1 F 1 f belt tension parameter f stat Hz m L f 0.1 t e L f Design fo Synchronous Belt Drives 3 If desired frequency coincides with actual measured frequency, then the belt is properly tensioned Result of belt calculation 1 CONTI SYNCHROBELT HTD synchronous drive belt 9 M 1 HTD toothed pulley PT0 M F 1 HTD toothed pulley PT5 M 7 7