Research On The Key Issues Of The Power Steering Pump Of Automobile

This paper is based on the enterprise project"Research on the steering pump's current issues"of the Changchun BAODI automobile parts manufacturing Co. Ltd.With the current rapid development of automobile industry,people have higher requirements about comfort and safety of automobile. The power steering pump is the"heart"part of the hydraulic assisted steering system, whose performance is directly related with the stability of the auto steering. This paper takes the heavy vehicle's vane-type steering pump of the Changchun BAODI automobile parts manufacturing Co. Ltd. as the study object, and does some research on the present issues of the steering pump.Based on my study, this paper is related to two aspects including optimization in structure and material selection of oil distribution casing. In view of the smaller size and more complicated flow state of hydraulic flow in the relief value, the physical model of basin in the relief value of the pump in this paper is established based on Fluent which is a kind of simulation software of fluid dynamics. And the mesh division, boundary definition and iterative calculation are completed based on the basic theories and methods of fluid dynamics. The shortcomings of current structures are proposed by the analysis of simulation results for the flow field. Two improved programs had been put forward via the conclusive, and the fluid simulation calculation of these two improved models is completed through the same method. Comparative analysis shows that the pressure and velocity fields of the improved model have been greatly improved than before. Above all, the feasibility of this method has been proved. The stator curve is identified as the main factor which caused excessive noise inside the vane pump, and the serious"soft impact"phenomenon which exists in that curve has been proved by analysis of constant acceleration stator curves that used on the steering pump. Meanwhile, some similar defects also had been found out in other common low-level stator curves. To reduce the noises and shocks, this paper proposed to replace the current curve by high-order curve, then according to the separate analysis of five/six/seven/eight-order curve, the speed, acceleration and it's change rate curves of the eight-order curve showed their continuous smooth natures. The optimized eight-order curve which has no impact, low noise and smooth movement is obtained by the optimization toolbox of Matlab. As to abrasion of oil distribution casing, this paper does two sets of experiments using high temperature, high speed machines with abrasion and friction. One of the experiments analyzes three frequently-used materials about their abrasion performance, so as to pick the best one to replace the present material of the oil distribution casing. The rate of wear and the friction coefficient are the main factors concerning the abrasion resistance in the experiments.And the other testifies the anti-abrasion performance of the oil distribution casing,and from which get the diffirence in anti-abrasion performance between the material with outer coating and without.