Radial Axial Load Check 17.03.2015
AKB Report Radial and axial loads of motor and gearbox 1) Introduction For certain drive dimensioning processes, radial and axial loads have to be checked. Fig. 1.1 shows the radial and axial forces acting on a gearbox shaft in an application. At present, DSD does not contain any radial and axial load check. In Fig. 1.2 / 1.3, you can find an overview of the Lenze motor and gearbox families. Fig. 1.1 Radial and axial forces on the motor shaft Fig. 1.2: Overview of Lenze motor families Fig. 1.3: Overview of Lenze gearbox families Radial_Axial_Load_Check_17.03.2015.docx Author: KH Weber, B. Obergöker 1 AKB Report 2) Typical applications with radial loads Typical applications include: - Cable drum directly mounted onto a gearbox shaft (e.g. hoist drives) - Omega belt pulley for linear conveyor sections - General toothed belt, V-belt, flat belt ratios (e.g. winders, fans, compressors, conveyor belts) - Sprocket on gearbox or motor shaft (e.g. materials-handling technology) - Rack module (materials handling) - Monorail overhead conveyors - Eccentric and crank drives Fig. 2.1: Toothed belt ratio at the gearbox Fig. 2.2: Omega belt ratio with stationary drive Fig. 2.3: Belt drive of a center winder Radial_Axial_Load_Check_17.03.2015.docx Author: KH Weber, B. Obergöker 2 AKB Report Fig. 2.4: Traction drives in a storage and retrieval unit Fig. 2.5: Hoist drive cable drum on the gearbox shaft Fig. 2.6: Belt positioning system Radial_Axial_Load_Check_17.03.2015.docx Author: KH Weber, B. Obergöker 3 AKB Report Fig. 2.7: V-belt transmission fan for air conditioning in buildings Fig. 2.8: Rotating tangential chain of a roller conveyor with sprocket at the gearbox shaft Fig. 2.9: Crank drive Fig. 2.10: Monorail overhead conveyor Radial_Axial_Load_Check_17.03.2015.docx Author: KH Weber, B. Obergöker 4 AKB Report 3) Typical applications with axial loads Fig. 3.1: Stirrer Radial_Axial_Load_Check_17.03.2015.docx Author: KH Weber, B. Obergöker 5 AKB Report 4) Determination of radial and axial loads Fig. 4.1 describes how to proceed to check radial and axial forces acting on the gearbox or motor shaft. Fig. 4.2 / 4.3 provide further information. The permissible limit loads can be obtained from the gearbox and motor catalogues. construction M, d d, X determination radial-/axial forces (Fig. 4.2) FR, FA, X catalogue data with standard/ reinforced bearing NOK · reinforced drive components · changed construction OK Fig. 4.1: Workflow – radial and axial load check 2M F Ft F F d 2 F F F 0 ( Fig. 4.3 ) 2 Fr F1 ² F2 ² 2F1 F2 cosß t pulley Fv, d, ß 1 v 2 v t Fr sprocket d T, α F r friction wheel d F1= F2= Fv= Ft= Fr= 2M d load side slack side prestressing force tangential force from transmitting torque radial force β= d= M= angle of wrap pulley/ sprocket effective diameter pulley / sprocket torque to be transmitted Fig. 4.2: Determination of radial and axial loads Radial_Axial_Load_Check_17.03.2015.docx Author: KH Weber, B. Obergöker 6 AKB Report MAntr F1 d2 Fr d1 ß F2 C F F ² F ² 2 F F cos ß ß 2 * (0,5 d 2 d 1 ) 2 c r 1 2 1 2 Fig. 4.3: Determination of angle of wrap β and radial force Fr for belt and chain drives Dimensioning example for determining the radial force: Pretension Torque Diameter Sprocket distance ( √( ) ) ( ) Radial_Axial_Load_Check_17.03.2015.docx ( Author: KH Weber, B. Obergöker ) 7 AKB Report 5) Reinforced bearings for high radial / axial loads For the following gearboxes and motors, you can optionally select reinforced bearings with increased values. For all other gearboxes and motors, the next bigger drive component is to be selected as an alternative. Gearbox families Reinforced bearings GST GST04……GST09 g500-H100…g500-H450 GKS, g500-B Only as C type GKR Only as C type GFL, g500-S Not provided for Motor families Reinforced bearings MCA Only as C type MH Only as C type MD Only as C type Radial_Axial_Load_Check_17.03.2015.docx Author: KH Weber, B. Obergöker 8 AKB Report 6) Dimensioning example – eccentric lifting device for materialshandling technology Via simulation and DSD, an eccentric lifting device has been dimensioned with a GST 07-2M gearbox. In an additional check, the radial load of the selected gearbox has to be checked to see if the gearbox is suitable for the occurring radial load. Gearbox: GST07- 2M-VBR-100-32; i= 32.267 Shaft: 40 x 80 d=40 mm; l = 80 mm Chain pinion: 12 teeth; d = 98.14 mm Pinion-shaft shoulder distance (Fig. 1.1) x = 46 mm Results from DSD dimensioning: Fig. 6.1 Eccentric lifting device in the bottom dead center (left) and in the top dead center (right) Calculation of the radial force Maximum radial force Equivalent radial force Determining the permissible radial force according to the gearbox catalogue: ( Radial_Axial_Load_Check_17.03.2015.docx ) Author: KH Weber, B. Obergöker 9 AKB Report Determining the additional load factor fw from the gearbox catalogue diagram (see Fig. 1.1). ; Fig. 6.2 Additional load factor catalogue) fw =0.95 at the output shaft for GST04…09-1, 2, 3 (… GST gearbox The average gearbox output speed is nav = 11.3 min-1. selection column n ≤ 16 Fig. 6.3: Permissible radial forces at the output with standard bearings (extract from the GST gearbox catalogue) According to the gearbox catalogue, the max. permissible radial force must not exceed 9500 N. Radial_Axial_Load_Check_17.03.2015.docx Author: KH Weber, B. Obergöker 10 AKB Report Result: Load is not permissible with standard bearings Selection of a gearbox with reinforced bearing: Fig. 6.4 Permissible radial forces at the output with reinforced bearing (… from GST gearbox catalogue) Peak value Result: Load is permissible with reinforced bearing Radial_Axial_Load_Check_17.03.2015.docx Author: KH Weber, B. Obergöker 11
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