Vibration Characteristics Of Tractor Cab Based On Rigid-Flexible Coupling

The NVH performance of tractors directly determines the quality of products,and is also an important indicator of comprehensive evaluation of their products.The driver's cab of a tractor is a carrier that isolated from the body.It can protect the human body from external injury and reduce or isolate the external noise.The influence of the vibration transmission channel on the internal frame and cover of the cab via the vibration damping link between the cab and the body is studied,and the vibration transmission rules of the tractor cab are also studied.It is of great significance to design and optimize the design of the structure.Based on the research idea of rigid flexible coupling,the stress and strain analysis and vibration mode of the internal structure parts of the tractor cab under the excitation of actual working conditions are simulated and tested.First,the CAD analysis model of the tractor cab and frame is established,and the necessary constraints such as the shift pair and the sleeve force required by the multi-body dynamic analysis are introduced,and the multi rigid body dynamic model is generated.The vibration acceleration signal before the four point vibration damping is applied to the constraint of multi-body dynamics for calculation and analysis.In the finite element model,the support of the cab and the components of the connecting structure are divided into the body grid,and the panel with the feature of the plate is divided into the surface mesh,and the sound cavity boundary element model is established.By adding mesh properties,material properties and rigid regions to the finite element model,a rigid flexible coupling multi-body dynamic analysis model for cab frame is established under the assumption of the rigid frame structure input terminal,which contains multi-body dynamic modal neutral files.Then,in the rigid flexible coupling multi body dynamic model of the cab frame,the actual vibration excitation acceleration data before the vibration damping are loaded into the drive of the shift pair,and the stress and strain obtained by the rigid flexible coupling model are calculated at different rotational speeds,and the occurrence process and the maximum position area of the stress and strain are determined.The structure mode of the cab and the vibration modes of the acoustic modes are discussed,and the structure of the cab is proved to be reasonable,and the structure of the modal frequency coupling is optimized.Finally,the test tests are carried out on the larger vibration area and seat position found in the modal analysis.The parameters of the cab floor and the damping pad are optimized.The optimization scheme is calculated by means of simulation and measurement,and the data are analyzed and compared to the optimized data.The results show that the test points of the cab are on the basis of the results.And the vibration of the vibration damping point is reduced in varying degrees,indicating that the optimization scheme of the structure is consistent with the expectation of the simulation scheme,and the vibration intensity of the cab is also greatly improved.This paper focuses on the dynamic characteristics of the model of the tractor cab frame based on rigid and flexible coupling,establishes the vibration transmission relationship between the frame and the cab,and uses the stress cloud map to quickly and accurately discover the maximum stress area,thus providing the basis for the structural optimization and providing guidance for the vibration control.