基于约束刚柔耦合系统的叉车振动研究

Vibration Study of Fork-lift Truck Based on the Constraint-rigid-flexible Coupling System

针对某型叉车行驶时座椅处振动强烈的性能缺陷开展研究,结合多体动力学方法,充分考虑叉车车架为空间柔性体以及路面对叉车动态性能的影响,建立基于约束刚柔耦合的叉车动力学模型,进行叉车行驶时动态特性仿真与评价。根据相关试验结果验证理论模型与仿真模型的正确性。在此基础上,针对座椅垂直振动对叉车的整车系统提出改进设计的措施:转向桥采用转轴为椭圆形且支座内有橡胶垫块的弹性铰接以及护顶架通过4处橡胶垫块与车架相连接,发动机盖铰接在护顶架上,座椅安装在发动机盖上,将发动机通过两处橡胶垫块(隔振垫)与车架连接。对改进后的整车系统在相同条件下进行仿真并通过试验加以验证,结果表明,叉车整车系统结构修改以后,其基频及座椅振动频率降低,振动能量减小,研究结论对叉车的整车开发或部件的振动性能优化具有一定的实用价值。

Researching into the performance deficiencies about vibrations of driver seat,while fork-lift truck is driving,and analyzing the influencing factor based on the multi-rigid-body dynamic method with considering the influence of flexibility of fork-lift frame and road on the dynamic characteristics of.A new rigid-flexible coupling dynamic model of fork-lift truck is established.Dynamic characteristics of the new established system are studied through simulating the system under different driving conditions.The theoretical model and the simulation results are validated through experiments.And then,for melioration of the performances of the fork-lift truck vertical vibration,improvement measures of complete engineering machines for decreasing the vertical vibration of seat is offered as following：The shaft from the steering bridge is used in the ellipse,and the elastic hinge is used by the rubber cushion block in the support;the overhead guard is connected with the frame by the rubber cushion blocks at four different locations,and the motor cover is hinged with the overhead guard,while the seat is fixed on the motor cover;the engine is fixed on the frame by the rubber cushion blocks（shock mount）in two different position.And then,for melioration of the performances of the fork-lift truck vertical vibration,some technical measures are put forward on the basis of simulation,which is validated by experiments under the same conditions.The results show that after the forklift vehicle system structure improving,the fundamental frequency of seat is lower and vibration energy is decreasing.The result proves the practical value of this method in the research of the vibration characteristics of complete engineering machine.