A fixed jib stepless variable amplitude control system for a crane and the crane

Abstract

The invention relates to a fixed jib stepless variable amplitude control system for a crane and the crane. The control system includes an electric proportional pressure reducing valve, a variable pump, a first reversing valve and a hydraulic oil cylinder for making the fixed jib variable amplitude; A reversing valve is located on the oil circuit between the variable pump and the hydraulic cylinder, the pressure oil output by the variable pump enters the hydraulic cylinder through the first reversing valve, and the electric proportional pressure reducing valve controls the displacement of the output pressure oil of the variable pump. The fixed jib stepless variable amplitude control system for a crane provided by the invention utilizes an electric proportional pressure reducing valve to control the displacement of a variable pump, realizes continuous variation of the displacement of the variable pump, has a wide speed regulation range, and has good fretting performance.

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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