Electro-hydraulic Proportional System Research Of Forming Hydraulic Press Of Heteropolarity Multilevel Magnetic Ring

The quality of powder metallurgy products are decided by the performance of the powder forming hydraulic press, which is the most essential equipment on the line of making powder metallurgy production. At present, the hot research spot about the powder forming hydraulic press is the application of electro-hydraulic proportional technology in the powder forming hydraulic press. Germany, US and other developed countries already has hade powder forming hydraulic press products based on the electro-hydraulic proportional technology, but which was at the blocked state. The domestic universities and research institutes which are engaged in the reach of high performance powder forming hydraulic press are very less, at present there is no report about powder forming hydraulic press products based on the electro-hydraulic proportional technology. The most domestic and foreign research related to powder forming hydraulic press performance mostly concentrates in enhancing the movement precision of powder forming hydraulic press, but rarely seen the literature of research combining the suppressed pressure, the suppressed speed with the powder forming mechanism. Unified the powder forming principle, the author made the discussion research on the design and control of suppressed pressure and speed in the forming process of heteropolarity multilevel magnetic ring.The main contents of this article are as follows:1.Improved the hydraulic system, the hydraulic cylinder of ordinary powder forming hydraulic press; proposed and used guards against the crack function on die head - spring structure; optimized the PLC controlling procedure of powder forming hydraulic press; gathered and analyzed the data of the hydraulic press running status, Optimized the running status of the hydraulic press; analyzed the reason of causing the product flaw, summarized the inevitable flaw of switch hydraulic press, proposed the necessity of researching powder forming hydraulic press based on electro-hydraulic proportional technology.2. Analyzed the change rule of product density of metal powder and the the suppression curve of heteropolarity multilevel magnetic ring, taken the heteropolarity multilevel magnetic ring of 134 model as an object, inferred the relationship between the suppressed pressure and the suppressed displacement according to the relationship between the suppressed pressure and the suppressed density or the suppressed density and the suppressed displacement; Analyzed the suppression speed and gathered data, inferred the formula of density change and curve. Proposed the speed and pressure changed suppression theory according to the suppression pressure curve and the suppression velocity curve.3. Designed a set of electro-hydraulic proportional system of forming hydraulic press of heteropolarity multilevel magnetic ring, established the mathematical model of the top plunger cylinder. According to the powder forming craft, Designed suppression working proceduresuppression speed changed curve, definited proportional direction valve hypothesis signal. Taken the relationship between the suppressed pressures and displacement of the 134 product as the hypothesis signal of proportional delivery valve. Combined with the hypothesis rate signal, made a simulated research for the suppressed process of the forming hydraulic press based on electro-hydraulic proportional system.4. Using the PID algorithm, carried on the simulation curve to approach the objective function, enhanced the controlling precision of the suppress pressure of the hydraulic press.