| Large mining excavator is the main equipment when exploiting strip mine ,our mineral resources is almost fitted to be exploited in the open air ,and according to the new planning and deployment of our country, we will construct and extend some big coal mine copper ore and iron ore which, show that we will need more bigger excavators.The swing mechanism is the important component of the excavator. Rotation time, energy consumption and the caloric given up by the swing brake system etc. occupy greater proportion to those in the whole work circulation of excavate system. The Performance of the swing mechanism has a significant impact on the overall performance. In this paper, the brake is an important part of the device at the rotary excavator components. Its braking performance is also an important indicator of performance of rotary. Therefore, it is very necessary we draw the relationship between the parameters of braking performance with the dynamic analysis.The model of this paper is created based on the relevant data of the 12m3 electric shovel which was produced by Fushun Mining Group. Taking into account that the ADAMS has difficulties to establish some of the more complex three-dimensional model, so first we set the three-dimensional solid model of the brake with the mature 3D modeling software Pro/E. In the conventional analysis, we almost use theoretical and experimental studies for the designing of the brake. Because this designing means lacks the instructing of modern design theory and method, there is greater blindness and a large number of hard work often be needed to gain a group of satisfactory schemes. In this way, not only the design efficiency is very low, but also it is very difficult to receive the best scheme with better economy and dependability. This paper established the brake 3D model directly exhibition the performance of various components of the angular velocity, the acceleration of the braking and the contacts, the pressure and the friction between the wheel and the brake tile. So it takes great convenience for the designing process of the brake.Through the interface program Mechanism/Pro we can get the Virtual Prototyping model in the dynamics analysis software ADAMS with the 3D model. Then considering the greatest degree of braking to simulate actual needs and with the constraints, the load we can get the VP model. The main constraint in this paper contains three types: the fixed joint, the Revolute joint, the Translational joint. And the three main loads in ADAMS: the internal load, the external load, the special load are all involved. The internal loading is the main component of some flexible connector, such as springs, buffers. This paper is inserted spring between the cylinder and the capper to simulate the load this spring brake process and when the gas was out from the cylinder, the spring play the role of backing up the piston rod. The main external load is: the load, the torque, the gravity. The special load is means to the contact and the friction. In this paper, between the brake pads and brake wheel of this constraint can be imposed friction brake embodied the role. After that we begin to do the dynamic analysis to the brake after we imposed the load and the constraints with Verification unmistakably.As a result of dynamical simulation and analysis of the brake models, we draw some conclusions below:1. The VP models built in this paper are proven to be accordant with the actual process on the whole. 2. The larger the dynamic friction coefficient, the smaller of the angular velocity at the same time. That because the greater the friction coefficient, the larger of the friction between the wheel and brake pads were greater, so the angular acceleration is small, and so the angular velocity is small. However, if the dynamic friction coefficient is too high, then there will be great instantaneous amplitude, which would lead to self-excited vibration of brake system and debase the stability of the brake. Therefore when selecting brake-shoe, the dynamic friction coefficient must fulfill the request of not only the brake capability but also the stability.3. Brake arm is the major components of the brake. We did the Static analysis with it. According to the measured data obtained maximum stress, we can get the conclusion that the brake arm's intensity is meet the requirements.4. Through the modal analysis on the brake arm and the brake pads, we get the natural frequency and vibration mode. It can be summed up how to avoid the elements resonance. This has raised a number of guidance to the practical operation of the brake to avoid the damage.Due to time constraints and my ability, the paper only perform the primary analysis of the dynamics characteristic of the brake system, we can also use this model for further analysis. For example, Adams can be used in the dynamic analysis of the results: the force versus time, relations campaign will be added to its finite element model to do the thermodynamic analysis. As the development of computer hardware and software algorithms to improve the analysis of the brake coupling contact there is a need to further research. In addition, the friction and wear, brake noise and vibration problems in the brake field are due to depth research.The solution of modeling in this paper is universal to apply to other friction studies that only need to change some of the parts at any time. In addition to, the conclusion of the problems encountered on the solution when we put the 3D model to ADAMS can also provide some suggestions to the relevant issues .The method that when we do the contact dynamic simulation analysis can be applied to other problems in the analysis of the contact problem. It takes much convenience for other working conditions. Do further research and analysis based on this paper can provide a more rapid and practical method for the brake designing.
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