Servo motor control-based multi-pump combination controlled hydraulic power system

Abstract

The invention provides a servo motor control-based multi-pump combination controlled hydraulic power system. The system comprises a host controller, at least two servo pumps, an oil pipe and an oil tank, wherein branch oil pipelines of all the servo pumps are connected together to form a main oil pipeline of the system; one of all the servo pumps is the main servo pump; the oil pipeline of the main servo pump forms a master control branch oil pipeline of the system; Each branch oil pipeline of all the servo pumps is connected with a check valve in serial before entering the main oil pipeline of the system; two ends of the check valve of the main servo pump are connected with main pressure controllers in parallel; the main pressure controller comprises a cartridge valve and a pressure difference orifice; an oil inlet cavity and a control valve of the cartridge valve and two ends of the pressure difference orifice are connected with two ends of the oil outlet and the oil inlet of the check valve of the main servo pump in parallel respectively; and an oil return cavity of the cartridge valve is connected to the oil tank. The system has low energy consumption of pressure maintenance, high pressure release speed and small impact of pressure release or load discharge on the oil pump and a servo drive system.

Description

【Technical field】 [0001] The invention relates to a hydraulic power system, in particular to a multi-pump combined control hydraulic power system based on servo motor control for an injection molding machine. 【Background technique】 [0002] We know that the working process of an injection molding machine is generally divided into stages such as mold clamping, injection, pressure maintaining, cooling, plasticizing, mold opening, and ejection. Different stages require hydraulic systems to provide hydraulic oil with different pressures and flows, so hydraulic oil Generally go through a cycle of pressurization, pressure maintenance and pressure relief. [0003] With the deepening awareness of energy saving and environmental protection, people put forward higher and higher requirements for the energy consumption and control precision of traditional injection molding machines. The emergence of servo motor driven oil pump control technology is a revolutionary progress in the combi...

AI Technical Summary

Problems solved by technology

However, this system has the following defects: the system pressure control is completed by multiple pumps, and there is a large amount of unnecessary energy consumption during pressure maintenance

This is because although a single pump is sufficient to meet the pressurization needs, for a large-tonnage injection molding machine hydraulic system, the compressed hydraulic oil in the hydraulic cylinder and pipeline has a large volume and high compression energy, and the discharge capacity of a servo pump alone It is not enough to meet the requirements of reducing pressure or releasing the compression energy in a very short time. Therefore, multiple servo pumps have to be used to achieve pressure control such as pressure holding and relief, but the problem brought about by this is the energy consumption of holding pressure. Large, the speed of pressure relief is slow, and the backflow of oil during pressure reduction or load relief has a large impact on the oil pump and servo drive system, which will shorten the service life of the oil pump and controller; multiple servo pumps run under load for a long time, which will also affect the Great impact on overload capacity

The servo motor works at low speed and high torque, and its mechanical efficiency is also very low

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