| The exploitation of wind energy has promoted the rapid development of wind power generation equipment in my country.In view of the large demand for bearings in this type of equipment,the research and development technology of bearings is not yet mature,and data shows that about 50% of gearbox failures originate from high-speed bearings.Therefore,it is necessary to focus on the performance of such bearings.Rigidity is an important indicator of bearing performance.Factors such as installation errors and fit tolerances during the assembly process will affect the changes in bearing clearance and load distribution,resulting in changes in bearing stiffness and affecting the vibration behavior of bearings and gearboxes.Therefore,research on the stiffness characteristics of cylindrical roller bearings taking into account the assembly effect can provide theoretical support for optimizing bearing assembly,which has important research significance.This paper takes wind power cylindrical roller bearings as the research object,mainly studies how the matching tolerance,assembly pre-tightening and the angle mismatch of the inner and outer ring can affect the stiffness of the bearing during the assembly process.The main research contents are as follows:(1)Based on the Hertz contact theory,an analytical formula for stiffness calculation considering bearing fit tolerances is established,and the influence of fit tolerances on bearing stiffness is studied by combining theoretical analysis and finite element methods;a finite element model considering the shape errors of shafts and bearing housings is established and analyzed.The influence of shape error on bearing contact performance and stiffness;establish a finite element model of bearing stiffness based on the existing bearing temperature field gradient model in the literature and analyze the influence of ring temperature change on bearing stiffness;(2)According to the corresponding elastic mechanics theory,a mechanical model that can calculate the pre-tightening force of the inner and outer ring end faces of the bearing under the condition of considering the tightening torque of the inner and outer rings of the bearing is constructed,and the bearing contact performance and stiffness are calculated according to the transformation relationship between the tightening torque and the pre-tightening force.Finite element analysis;(3)Based on the slicing theory of roller and raceway,consider the contact stiffness of the bearing roller and the inner and outer raceway contact pairs,use the stiffness parallel formula to propose the stiffness calculation method of the inner and outer ring angle misalignment caused by the installation error during the assembly of the bearing,carry out the research on the influence of the angular misalignment on the radial stiffness and angular stiffness of the bearing combined with finite element;(4)Based on the stiffness identification method of the cylindrical roller bearing under the tightening torque and angular misalignment of the compression nut,a test bench that can simulate the two working conditions of the compression nut of the bearing inner and outer ring and the angular misalignment of the inner and outer ring is designed and built.Carry out bearing stiffness test research under different working conditions to reveal the influence of compression force and angle misalignment on bearing stiffness.Through the research of this article,the stiffness theory model and finite element model of the cylindrical roller bearing under different assembly conditions have been established,and the bearing stiffness test bench that simulates the assembly process has been developed,and the factors such as fit tolerance,assembly pre-tightening and angle misalignment have been clarified.The influence mechanism on the stiffness characteristics of cylindrical roller bearings provides theoretical support and technical reference for the reasonable assembly of cylindrical roller bearings. |
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