Control oil circuit and engineering machine

Abstract

The invention relates to the technical field of control of hoisting machineries, and discloses a control oil circuit and an engineering machine. The control oil circuit comprises a reversing valve anda balance valve; a first oil circuit is connected with a first working oil port of the reversing valve; a second oil circuit is connected with a third oil port of the balance valve; an oil inlet oilcircuit is connected with an oil inlet of the reversing valve; a first adjustable throttling valve is connected between the first oil circuit and a first oil port of the balance valve; and a second working oil port is communicated with a second oil port of the balance valve. In the application of the control oil circuit, the first oil circuit is connected with a descending port of a hydraulic motor, and the second oil circuit is connected with a rising opening of the hydraulic motor; the reversing valve is adjusted to a second position, the first adjustable throttling valve is then opened, theoil inlet pressure makes the pilot pressure port X pressure of the balance valve increase to open the balance valve, so that the return oil of the hydraulic motor can conduct the return oil through the balance valve; and the opening pressure of the balance valve is adjusted according to the required working speed, the stable and reliable descending of the hoisting mechanism of the closed system is then realized, the stable descending of heavy object is ensured, and the heavy object can be safely placed on the ground.

Description

technical field [0001] The invention relates to the technical field of hoisting machinery control, in particular to a control oil circuit and an engineering machine. Background technique [0002] During the hoisting operation of the hoisting machinery, failures may occur, which may cause the heavy objects to be lifted suddenly unable to work. At present, some cranes can use the residual pressure of the accumulator to open the balance valve of the luffing cylinder to realize emergency lowering of heavy objects in some cases by lowering their own weight, but this method has relatively large limitations. The machinery cannot be realized, and in the current emergency device, the winch mechanism corresponding to the closed system control cannot realize safe descent. [0003] For example, in an existing form, a luffing oil cylinder and a balance valve are usually configured. When the vehicle loses power or part of the power, use the residual pressure of the accumulator of the ve...

AI Technical Summary

Problems solved by technology

[0004] In another form, the lowering operation of the hoisting mechanism can be realized by controlling the opening of the balance valve. However, due to the luffing action, the amplitude of the weight increases and the torque of the weight increases, which is prone to overloading, and the practical effect of this device is limited. , prone to major accidents due to overloading

This form has a limited scope of use, and the method of controlling the winch corresponding to the closed system cannot achieve safe descent

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