Modernization of the Hydraulic System of an 8-MN Radial Forging Machine

Abstract

Chelyabinsk) have modernized the hydraulic system of the R800 radial forging machine at the association’s production facility. The four-die machine, made by the company SACK, has a pulsator-type hydraulic drive for the dies and a hydraulicintensifier-based system that compensates for errors in the dimensions of the forged product. The dies are installed on rotating levers. The goals of the modernization, scheduled to coincide with an overhaul of the machine done after more than 20 years of service, were as follows: • an improvement in the durability of the machine; • an improvement in its efficiency; • broadening of its functional capabilities. During the modernization effort, we equipped the machine with a system of sensors and instruments to monitor their readings. This allows early detection of deviations in the operating characteristics of the main components. The system that protects the machine from overloads was also improved. Fine filters equipped with metal gauze that can be used repeatedly were installed in the delivery lines of all of the pumps along with electronic devices that give a visual indication of contamination. We reduced the hydraulic resistance of the sections of the hydraulic system located between each of the jerk pumps and the corresponding hydraulic tank. The working chamber of each pump is connected to the tank in order to be able to stop the corresponding die (during the period of operation of the machine in the “STOP FORGING” regime). A system was installed to compensate for errors in the dimensions of the product. This system operates within a wide range of values based on the volume of the hydraulic fluid and can be used either to deliver hydraulic fluid to each power circuit between the pump and the main (working) hydraulic cylinder or to remove fluid from that the circuit. Part of the modernization involved equipping all of the tanks with current sensors to measure the level and temperature of the hydraulic fluid. Current sensors for measuring pressure were installed in the delivery lines of the pumps, the delivery tanks, the hydraulic lines connected with the working chambers of the hydraulic cylinders that clamp the grip of the manipulators, and lines leading to the chambers of several of the machine’s pneumo-hydraulic accumulators. Turbine-type flowmeters were installed to measure the rate of flow of the liquid lubricant to the bearings of the reduction gears of the pump drive, and vibro-acoustic flowmeters were installed to measure the rate of flow of coolant water through the heat-exchangers (oil coolers). The temperature of the reduction-gear bearings and the large-end bearings of the pumps is monitored by means of current transducers. The signals from these sensors and the other control-and-measuring devices – the transducers that track Metallurgist, Vol. 46, Nos. 11–12, 2002