Development Of Comprehensive Test System And Experimental Research For Multi-way Valves

Multi-way valve used to control several hydraulic actuators is a kind of multi-function integrated valve, which integrates directional valve, check valve, relief valve, shunt valve and so on. It was widely used in construction machinery, because of its compact structure and simple pipeline connection. As one of core components in the hydraulic system of construction machine, the performance of multi-way valve decides the level of the whole machine. In order to improve the quality and performance of the multi-way valve, it is quite important to test the characteristic of the multi-way valve fully and accurately before installing it in the mobile machine. But the functions of existing test systems for multi-way valves are not very versatile; systems that can test the universal performance as well as some special functions of multi-way valves like confluence, priority, negative control and so on are rare in China. Besides, there is still a gap between the domestic and some famous hydraulic foreign manufacturers in multi-way valves with high performance, especially in high-pressure and flow ones, and the study on characteristics of multi-way valves is not in deep. Therefore, it can play an important role in improving the whole performance and shortening the gap of designing between domestic and foreign products to design a comprehensive test system, which can reflect typical characteristics of multi-way valves.In this thesis, a comprehensive test system is developed for multi-way valves according to the industry standards. Dynamic and static features are studied by experiment and simulation based on a certain multi-way valve to provide theoretical guidance for the development and design of it. The whole scheme is proposed according to the requirements for multi-way valves testing and comparison for the scheme for each functional unit of the test system. The integrated and optimize design of hydraulic and testing system is carried out, the whole hardware and software of the comprehensive test system are designed, and the test process of testing for multi-way valves is well planned. The experiment on a typical multi-way valve is conducted, and the simulation model is verified by the testing results. The dynamics of functions like confluence, priority, flow regeneration, and negative control are studied by simulation, and the relation between structural parameters and dynamic performance is revealed, which can the design of this typical valve. Each chapter of this paper is introduced as follows:In chapter 1, the scheme and characteristics of each kind of multi-way valves are introduced, and the trend of development is also summarized; the current situation of research on multi-way valves testing systems is analyzed. Finally, the significance and main research subjects of this paper are presented.In chapter 2, the related standards for multi-way valves testing are analyzed. The whole scheme of the comprehensive test system is proposed by combining the test items and methods, also considering some important functional characteristics, and then the scheme for each functional unit are compared and analyzed. The main characteristics of the test system in this paper are inducted.In chapter 3, each functional unit of hydraulic system is designed based upon compact design and convenient operation, under the context that the test functions are fulfilled. Optimization of the test and control system is carried out according to the requirements of multi-way valve testing; the software and hardware are configured taking advantage of programmed logic controller and data acquisition device, which can realize the control of test system, the display and processing of test data. The process of multi-way valve testing is planned properly under the testing standard.In chapter 4, the experimental research on a certain multi-way valve is carried out on the basis of the comprehensive test system. The test items as well as their realization are analyzed in details, and related tests of characteristics of the valve are conducted. The test results are analyzed combining the functional principle and structural characteristics that can provide experimental support for the further research on the action mechanism of the tested multi-way valve.In chapter 5, the simulation model of multi-way valve is built, and verified by experiment, then the characteristics like confluence, priority, flow regeneration, and negative control of the valve is studied. Structural parameters that affect the dynamics of thevalve are obtained by variable parametric analysis.In chapter 6, conclusions in this thesis are summarized and future research proposals are suggested.