Technical Manual for Ribbed Belt Drives

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Diagram 2 Ribbed Belt Tension GraphsDesign HintsRibbed Belt TensionBelt deflection per 100 mm span length E (mm)f (N)Section k (per Rib)PH 0.005 3.0PJ 0.009 5.0PK 0.020 7.5Static belt tension per rib T (N)f (N)Section k (per Rib)PL 0.036 10.0PM 0.123 25.0Belt deflection per 100 mm span length E (mm)Static belt tension per rib T (N)41
Design HintsRibbed Belt TensionII. Belt Tensioning using a ”Length AdditionalValue”It has become evident that span deflection methods are notalways the ideal checking procedures for ribbed belts. Thefollowing very simple method for the determination of the belttension is therefore recommended:1. Calculate the static belt tension “T”.500 · (2.03 – cT ≈ 1 ) · P B+ k · v 2c 1 · z · v2. The outside length L a of the Ribbed Belt should be measured onthe top surface with the belt slack prior to fitting it to the drive.Measurement may also be taken on the drive itself, but withouttension.Example::P B = 23.4 kWc 1 = 1.0v= 16.6 m/sDrive specification with Optibelt-RB Ribbed Belt 12 PL 1075T ≈500 · (2.03 – 1.0) · 23.41.0 · 12 · 16.6+ 0.036 · 16.6 2 ≈ 70 NWhen fitted for the first time, the tension should bemultiplied by a factor of 1.3.T ≈ 1,3 · 70 ≈ 91 N3. Calculate the length additional value “A” by using the formula:A ≈ L est · RLength measured on the back of the belt whilst slackA ≈ 1075 · 0.00264 ≈ 3 mmR = Stretch factor from table 19 page 43.4. This length additional value A should then be added to themeasured outside length (from step 2).L a ∗ ≈ L a + ATighten the belt until the length measured around the outside is1103 mm. The belt is then correctly tensioned.L a ∗ ≈ 1100 + 3 = 1103 mm5. The ribbed belt should then be tensioned until the outside lengthL a * calculated in step 4 is obtained. The belt tension will then becorrect.6. If the drive is to be retensioned, the ribbed belt must first beslackened off so that it can be measured in a stress freecondition. The procedure as detailed in steps 4. and 5. is thenrepeated.IV.Checking the Belt Tension by Speed MeasurementIn this method, the belt tension is checked using the theoreticalslip. The speeds of the driver and driven pulleys are measuredfirst in an unloaded and then in a loaded condition.III. Checking the Ribbed Belt Tension by Measurement ofthe Static Shaft LoadingA very accurate method for the setting of the correct belt tensionis by direct measurement of the static shaft loadingusing the formula:S = Slip (%)n 1L = Speed of driver pulley, unloaded(r.p.m.) (min -1 )n 2L = Speed of driven pulley, unloaded(r.p.m.) (min -1 )n 1B = Speed of driver pulley,under load (r.p.m.) (min -1 )n 2B = Speed of driven pulley,under load (r.p.m.) (min -1 )Formula for the calculation of slip:S a ≈ 2 T · sinβ2· zn 1L /n 2LS = (1 – ) · 100n 1B /n 2B42This checking method, however, does call for specialisedmeasuring instruments.At the rated loading, the slip should not exceed 1%. The beltservice is considerably shortened due to excessive flank wearwith an unacceptably low initial tension or under extremeloading conditions, with slip in excess of 2%.
Page 1 and 2: Technical Manualfor Ribbed Belt Dri
Page 3 and 4: Distribution Organisation North Ame
Page 5 and 6: ContentsIntroduction . . . . . . .
Page 7 and 8: Standard RangeRibbed BeltsPosition
Page 9 and 10: Drive DesignAbreviations used in Fo
Page 11 and 12: Drive DesignBelt Length Correction
Page 13 and 14: Drive DesignMinimum Allowances x/y
Page 15 and 16: Drive DesignA Guide to Selecting Ri
Page 17 and 18: Drive DesignFormulae and Drive Desi
Page 19 and 20: Section PHPower Ratings P N (kW) pe
Page 21 and 22: Section PKPower Ratings P N (kW) pe
Page 23 and 24: Section PMPower Ratings P N (kW) pe
Page 25 and 26: Special DrivesV-Flat DriveCalculati
Page 27 and 28: Special DrivesTensioning / Guide Pu
Page 29 and 30: Ribbed Belt PulleysMeasuring Pulley
Page 31 and 32: Ribbed Belt Pulleysbored for taper
Page 41: Design HintsRibbed Belt TensionThe
Page 45 and 46: Design HintsOptikrik Tension Gauges
Page 47 and 48: Design HintsLength Tolerances - Ins
Page 49 and 50: Design HintsProblems - Causes - Rem
Page 51 and 52: Data SheetFor Drive Calculation/Che
Page 53 and 54: Standard Rangeoptibelt-TB Taper Bus

Technical Manual for Ribbed Belt Drives

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