| Based on "twelfth five-year" national science and technology support plan project "energy saving and safety oriented integrated intelligent engineering machinery and equipment research and development"(project number:2013BAF07B04), paper set up the11degrees of freedom vibration system model according to the wheel loader actual work situation and its real structure conform and combined with the pseudo-excitation method analysis the main factors influencing the dynamic characteristics of wheel loader structure system.Wheel loader is a kind of shoveling transport machinery, widely used in mining, construction, agriculture, water conservancy and other large engineering field, is convenient and quick to operate, flexible, easy to use and repair etc, is one of the important engineering machinery and equipment.According to existing wheel loader design and research and development trend in our country, the production and research and development focuses on models for3to5ton, notably the5t model is most concentrated, but with the change of market demand situation, the development of engineering machinery and equipment has become increasingly large, and, in order to improve project efficiency, speed of wheel loader when working with vehicle stability is proposed. Wheel loader working environment is generally poor, poor road conditions, and its own characteristics and makes the frame and wheel loader adopts bolt connection between drive axle, inelastic suspension device, thus for long distances and transitions in the condition of the vehicle structure can effectively buffer the impact of the high speed and attenuation and vibration, and influence the driver’s physical and mental health, reduce the work reliability and service life of the loader parts, wheel loader constraints become to high speed, efficiency, the development of the important factors. Therefore, it is necessary for large power system with the features of wheel loader structure system in-depth research, to find, the factors which influence the dynamic characteristics of the structural system related both to effectively improve the driver’s operation comfort, keep carrying the integrity of the goods, can also for the future development and improvement of the loader to provide certain theoretical basis.In this paper, based on the test data, the establishment of working device suspended elastic equivalent model and according to the actual working condition to analyze its dynamic characteristics, analysis the mechanics characteristic of main elastic damping components to establish consistent with the actual structure of the wheel loader11degrees of freedom vibration system model, using structural system dynamic characteristics of wheel loader virtual excitation method carries on the system research, analysis the main factors influencing the dynamic characteristics of wheel loader structure system, focusing on external incentives change, change regulation of the system response, in order to improve the structure of the wheel loader system provides theory basis for dynamic characteristics, also as a model to improve and upgrade parts of theoretical reference.According to the work device of the type80wheel loader set up the technical data and the former frame just-elastic coupling model, the model80wheel loader working device and front frame is load and partial load condition of the whole operation cycle simulation, are obtained with different partial load, the stress of the working device’s key hinge point, deflection is obtained on the impact of load position on the different hinge point stress change rule. Work device of the simulation results show that the largest stress of the hinge point is movable arm and front frame hinged point, partial load conditions, the hinge point stress distribution is more serious. Function is obtained by the simulation analysis to the work unit movable arm oil cylinder and the turning force on the cylinder, it is analysis of movable arm oil cylinder with turning cylinder dynamic operating characteristics.In this paper, the type80wheel loader working device of oil cylinder dynamic working characteristics are studied, through the test measurement type80wheel loader a spade work circulation pump outlet pressure and movable arm oil cylinder and turn the bucket cylinder rod and rodless cavity pressure, get the working pump outlet pressure and movable arm oil cylinder with turning cylinder rod and rodless cavity pressure change characteristic curve, to establish open and close the driving stability system two kinds of oil cylinder under different working condition of mechanical model, its general expressions of stiffness coefficient and damping coefficient, the measured data based on test research unit movable arm oil cylinder and turning dynamic characteristic of the oil cylinder, the movable arm oil cylinder under different working conditions is obtained and turning cylinder stiffness coefficient and damping coefficient curve, dynamic characteristics analysis of various parameters on the oil cylinder system. Theoretical analysis of test data was applied to the research method of combining practice and theory, to improve the authenticity and the credibility of the findings.For wheel loader elastic damping components-seat, rubber shock absorber and tire dynamics model, according to the actual working condition analysis of factors influencing the dynamic characteristics of the damping components each. Research results show that air hanging wheel loader seat, in the air under the same pressure, which can effectively keep the seat height and stability of the dynamic characteristics. This paper also analyzed the tire load and partial load condition is the load and the mechanical properties of the results show that under the same working condition, the tires in inflation pressure of0.39MPa when the optimum stiffness and damping properties, structure of system dynamic simulation results also prove the conclusion.System is introduced in this paper the theoretical basis for the pseudo-excitation method, analysis of wheel loader virtual excitation method is used to research dynamic characteristics of the structural system feasibility, accuracy and validity. Wheel loader based on the actual structure and the working characteristics, the establishment of model80wheel loader vehicle11degrees of freedom vibration system parametric model, the accurate determination on the basis of the simulation parameters, according to different working condition of type80wheel loader system dynamic simulation, get the response power spectral density curve, determine influence the dynamic characteristics of wheel loader structure system in all kinds of factors and the influence degree of various factors on the corresponding amount, and according to the driver’s subjective feelings of comfort degree combination condition and parameters selection Suggestions are given.Thesis study, this paper USES the parametric vibration simulation modeling method and pseudo-excitation method can be applied to different models of wheel loader, the versatility, expand the wheel loader system structure dynamic analysis model and simulation method, the application scope of the design of wheel loader and improvement has certain help, the dynamic characteristics of wheel loader structure system for the future research has certain guiding significance. |
PDF Full Text Request