Fixed fly jib stepless amplitude-variation control system for crane and crane

Abstract

The invention relates a fixed fly jib stepless amplitude-variation control system for a crane and the crane. The control system comprises an electronic proportional pressure-reducing valve, a variable pump, a first reversing valve, and a hydraulic oil cylinder for varying the amplitude of a fixed fly jib, wherein the first reversing valve is positioned on an oil line between the variable pump and the hydraulic oil cylinder; the pressure oil output by the variable pump is input in the hydraulic oil cylinder via the first reversing valve; the electronic proportional pressure-reducing valve controls the discharge volume of the output pressure oil of the variable pump. The control system provided by the invention utilizes the electronic proportional pressure-reducing valve for controlling the discharge volume of the variable pump so as to realize the continuous variation of the discharge value of the variable pump, and is wide in speed regulating range and good in jogging property.

Description

technical field [0001] The invention relates to the field of engineering machinery, in particular to a stepless amplitude variable control system for a fixed jib used in a crane and a crane. Background technique [0002] On modern hoisting machinery, as the tonnage increases, the length and weight of the outrigger are also increasing, so the fixed jib becomes an important tool for extending the length of the outrigger. However, the conventional fixed jib can only achieve 0°, 15° and 30° range changes. When encountering a narrow space at a high place, it will not be able to achieve hoisting, which will eventually bring great difficulties and dangers to the user's installation. [0003] The electric proportional pressure reducing valve can flexibly use the current signal, and by changing the magnitude of the current, the output pressure of the electric proportional pressure reducing valve can be changed with the change of the current. [0004] The existing fixed jib stepless ...

AI Technical Summary

Problems solved by technology

[0005] The existing fixed jib stepless luffing system has the following disadvantages: 1. The displacement of the oil pump is fixed, the speed regulation range is narrow, and the fretting performance is poor; 2. The system pressure setting is low, the size of the oil cylinder is large, and the lifting performance is low; 3. There is no oil cylinder pressure maintaining device, which cannot prevent the danger of internal leakage of the oil cylinder

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