| With the development of machine in the direction of high precision and high reliability,people propose higher requirements for precision and reliability of mechanical products.Because mechanical products are usually consist of various kinds of transmission mechanism,the reliable problems for mechanical system is increasingly prominent in which the kinematic accuracy of mechanism is considered as an important index. Therefore, whether mechanism kinematic precision is reliable has attracted widespread attention. There are many factors which affect the reliability of mechanism kinematic precision and can’t be ignored. In order to ensure that mechanical products meet the requirements of engineering, tests for reliability are necessary. However, in the traditional tests for mechanical reliability, it is too difficult to meet the requirements of rapid development for modern mechanical products because of the complex test equipment, longer test cycle and higher cost. Due to that problem, how to use computer simulation technology to solve the problem of design and evaluation for mechanical reliability has become a research hot spot with the rapid development of computer speed and various of simulation software are widely used for it. For a mechanical product, people are more interested in its service life under the rated speed, especially for amateurs. Thus, the research works of this paper are as follows:1. During the use of mechanical product, the factors which affect the reliability of mechanism kinematic precision are divided into the cumulative and non-cumulative factors according to whether the errors of factor will accumulate or not. A simulation test method for reliability in kinematic accuracy of planar mechanism under the coupling action of non-cumulative and cumulative factors is put forward. The failure of mechanism kinematic precision is used as the core factor and reliability model for mechanism is established with considering various coupling relationship between the factors. Random sampling is done by using the method of Monte Carlo and specimens for reliability simulation test are established.The state of mechanism is updated gradually with wastage accumulation in the certain cycle of movement as the cycle of loss. At the same time, adopting the method of simulation test to judge whether the specimen meets the requirement of precision to judge whether the specimen is failed, the process of mechanism’s failure is simulated. Besides, statistical analysises for failure conditions of specimens are done to obtain the evolution rule of mechanism kinematic reliability.2. The Archard model is improved and a model for the wear analysis of revolute pair in mechanism is established based on the wear characteristics of the hinge revolute pair. Besides,the wear rate of hinge is calculated according to the model. A wear reliability interference model is established on the basis of the wear rate and the maximum wear clearance of the hinge. At the same time, analyzing the randomness and fuzziness of mechanism’s wear failure and establishing the fuzzy reliability life of evaluation model according to the reliability theory and fuzzy set theory. Lastly, this paper discusses the determination method of subordinate function. Based on the evolution of the probability of hinge wear reliability and fuzzy reliability against the time, this paper establishes the rule curve and makes a contrast analysis.3. This paper makes an experiment research of kinematic precision reliability simulation by taking slider-crank mechanism as the research object. The research shows the evolution rule of kinematic precision reliability and the reliability life of the mechanism. It verifies the feasibility of the method. |
