This paper analyzes the deficiencies of the test method of the power steering hydraulic pump, puts forward a new test method, proved by the production practice, the test method is easy to operate, the test results can truly and accurately reflect the steering hydraulic pump performance, and introduced the power Turn to hydraulic pump test equipment. 1. INTRODUCTION Automobile power steering hydraulic pump is the heart of power steering system, its performance is good or bad on the performance of automotive power steering system has an important impact, and will directly affect the steering and steering stability of the car. In addition, with the continuous introduction of new materials, new processes and structures, as well as the introduction of large numbers of high-speed steering hydraulic pumps for passenger cars, more and more research is needed on the performance of steering hydraulic pumps. Therefore, the test methods of steering hydraulic pumps must be further studied Explore, put forward effective test methods, improve the test means, in-depth study of steering hydraulic pump characteristics. Power steering hydraulic pump in the test process, the main parameters to be measured in addition to the general hydraulic pump with the temperature, flow, pressure, speed, torque and other parameters, the power steering hydraulic pump due to the special structure and the use of requirements it has Therefore, how to accurately and conveniently measure the performance parameters of the steering hydraulic pump when developing a power steering hydraulic pump test stand is the most crucial issue. 2. Power steering hydraulic pump test method Steering hydraulic pump test standard "ZBT23002 vehicle power steering hydraulic pump bench test method" was started in 1984, promulgated in 1987, has been used for more than 10 years. At that time, the domestic automobile power steering hydraulic pump products are gear pumps, sedans steering hydraulic pump or blank. With the rapid development of automobile industry in recent years, the power steering pump industry has made great strides. The steering vane pump has almost replaced the gear pump. The sedan steering hydraulic pump has been widely used, especially the introduction of a large number of foreign technologies. The original test method Has been more backward, can not fully and accurately detect existing products. In particular, in the first quarter of 1997, Chongqing Automobile Research Institute found that the original test method far failed to meet the testing requirements of existing products and was difficult to test during the task of undertaking the task of spot checking the quality of hydraulic steering pump delivered by the State Bureau of Technical Supervision. Operation, the quality of the product is difficult to make a comprehensive, fair and accurate evaluation. Therefore, in order to meet the needs of the development of China's automobile industry products, effectively control the quality of the products, it is necessary to conduct in-depth discussion and research on the test methods. 2.1 0.85pmax pressure concept The original test method requirements do running, flow testing and other performance tests, the product is under the maximum working pressure pmax conditions, then turn to the hydraulic pump safety valve has been fully open, at a flow of 0 off Flow state, simply can not test, and easy to pump. Test to avoid steering hydraulic pump safety valve open, before the test, you must lock the steering pump safety valve. This approach is equivalent to the hydraulic pump has been adjusted, so the method is neither scientific nor loading conditions, but also can not be more comprehensive and accurate detection of product performance. Therefore put forward the concept of 0.85pmax pressure, that is, the product under the conditions of 0.85 times the highest pressure running and flow detection and other performance testing, then turn to the hydraulic pump safety valve will not open, so the detected performance accurately reflects the steering hydraulic Pump the real situation. 2.2 The air tightness test The original test method is not required air tightness test, through a large number of tests showed that the air tightness test can accurately and reliably reflect the steering seal seal and the quality of the assembly between the parts, and the test Simple, feasible, low cost, easy to promote the application. 2.3 reliability test of the oil temperature steering hydraulic pump working conditions than the general engineering use of pump conditions is much more complicated. When used, the steering hydraulic pump is often in the complex conditions of speed and pressure change, the oil temperature changes drastically and the range is large. In addition to the steering pump port are installed at the orifice of a small aperture, the excess flow overflow overflow, and return directly into the oil chamber, the steering pump to form a small cycle, which makes the steering pump heat Phenomenon than the average pump is much more serious. At the same time, due to the structural constraints, the steering hydraulic pump is generally installed on the vehicle next to the engine, the ambient temperature is high, so steering hydraulic pump heating more serious. And little power steering fluid system, usually 1 ~ 3L, the heat is not easy to distribute.
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