Hydraulic system of hydraulic shear

Abstract

The invention provides a hydraulic system of a hydraulic shear. The hydraulic system comprises a hydraulic oil tank, a hydraulic power system and a shearing hydraulic cylinder connected with the hydraulic shear. The hydraulic oil tank, the hydraulic power system and the shearing hydraulic cylinder are connected to a hydraulic main loop. The hydraulic system further comprises a hydraulic shut-off valve set and a hydraulic reversing valve, wherein the hydraulic shut-off valve set is connected to the hydraulic main loop to enable the main loop to be switched on or shut off for reversing, and the hydraulic reversing valve is used for controlling on-off of the hydraulic shut-off valve set. The principle of volume speed regulation is adopted, the hydraulic shut-off valve set is connected between the hydraulic oil tank and the shearing hydraulic cylinder and used as a switching valve, and when hydraulic oil flows through the hydraulic shut-off valve set, throttling loss is hardly generated; the hydraulic reversing valve is only used for control, the flow rate of hydraulic oil flowing through the hydraulic reversing valve is quite small, the little throttling loss is generated, therefore, the hydraulic power system can provide the corresponding pressure oil and the flow according to the force and speed needed by action of the hydraulic shear, energy consumption of the hydraulic shear in the shearing process can be minimized, and energy source waste is reduced.

Description

technical field [0001] The invention belongs to the technical field of metallurgical equipment, and in particular relates to a hydraulic system of hydraulic shears. Background technique [0002] As an important equipment on the processing and post-processing line of metal sheet and strip products, hydraulic shears are basically controlled by hydraulic valves, and its principle belongs to throttling and speed control. figure 1 Shown is a schematic diagram of the principle of the prior art. In the prior art, a constant pressure variable pump is used as the power system of the hydraulic shear, and the pressure of the hydraulic oil driving and controlling the hydraulic shear is constant. According to the requirements of the shearing process, the pressure oil that actually enters the shearing hydraulic cylinder is controlled by throttling and speed regulation through a proportional reversing valve or a speed regulating valve to meet the flow and pressure required for shearing. c...

AI Technical Summary

Problems solved by technology

According to the requirements of the shearing process, the pressure oil that actually enters the shearing hydraulic cylinder is controlled by throttling and speed regulation through a proportional reversing valve or a speed regulating valve to meet the flow and pressure required for shearing. large energy loss in

[0003] Specifically, due to the need to consider smooth threading and other reasons, the opening of the upper and lower cutting edges of hydraulic shears is often relatively large, but in fact the distance between the lower cutting edges and the shearing action ( figure 2 In L1) generally only less than the maximum stroke ( figure 2 30% of L2), that is to say, 70% of the stroke of a shearing hydraulic cylinder is no-load, and the 70% of the no-load stroke actually requires a lower hydraulic pressure, so a large part of the hydraulic energy The loss is in the throttling and speed regulation control link of the hydraulic valve; at the same time, the hydraulic shear is completely empty during the return process, the required pressure is very low, and there is also a large throttling loss of hydraulic oil; in addition, the hydraulic shear is in the After one or more shearing actions are completed, it is necessary to wait for the next batch of shearing commands. Although the hydraulic shears have no flow requirements during this period, there is no throttling energy loss of the hydraulic shears themselves. The power system maintains a constant hydraulic source, which is generally implemented by an asynchronous motor and a constant pressure variable pump. At this time, the asynchronous motor is also running at the rated speed, and there is a large amount of power loss.

The energy loss of the above three main aspects accounts for more than 50% of the energy of the hydraulic shear control system, that is to say, nearly half of the energy of the conventional hydraulic shear is wasted

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