Optimal Assembly Tolerance Design Of Shafting In The All-direction Propeller

The all-direction propeller is an important kind of marine power equipment, whose assembly level is of importance for its working performance. In the development of the all-direction propeller, it is difficult to meet the requirements of the assembly precision because of its structural complexity. Therefore, reasonable assembly tolerance design is an effective way to improve the assembly accuracy, reduce R & D costs and improve the success rate of an assembly. With the development of computer aided technology, the design and development of computer aided tolerance design play an important role in the process of product design and development. This paper aims at the full revolving propeller with its practical engineering requirements, focuses on tolerance modeling, tolerance analysis, and tolerance allocation, researches on the geometric precision design, and tries to improve tolerance optimization design method of efficiency. The main work of this paper is as follows:First, 3D tolerance modeling method of the propeller shaft of the whole rotary propeller is studied in the paper. Aiming at the specific structure of the transmission system, a new method for solving the parallel support screw parameter is put forward. Subsequently, this method is combined with the Jacobian spinors model to establish the 3D tolerance analysis model. Afterwards, the analysis model of contribution degree calculation method is given. Based on the work mentioned above, the modeling and analysis method for 3D tolerances for solving parallel dimension chain is proposed. Applying the method above, 3D tolerance modeling and analysis of the propeller shaft of the all-direction propeller are carried out, and the 3D tolerance analysis model of the assembly of the transmission shaft is set up, as well as its analysis and calculation.Then, the tolerance allocation and optimization method based on the statistical tolerance optimization technique are studied. A machining-cost-based tolerance allocation and optimization model is the established, with the constraints of assemble functions, machining capacity and assembly success rate. By applying this model, the feasibility for tolerance allocation and optimization will be improved. An optimization algorithm combining with the Grey Wolf algorithm and Monte Carlo algorithm is proposed to solve the tolerance allocation optimization problem effectively. As an engineering example, the optimization method is applied to the transmission shaft of the full revolving propeller. The effectiveness of the proposed algorithm is verified to meet the functional requirements and assembly of the success rate, reduce the machining accuracy and machining cost, satisfy the principle of economy.