Crane and its hydraulic system

Abstract

The invention provides a crane and its hydraulic system. The hydraulic system includes a load-sensing pump and a first actuator and a second actuator driven by it. The first actuator includes a luffing cylinder connected in series with the load-sensing pump, a balance The valve and the first load-sensing multi-way valve also include an accumulator, and the accumulator is provided with one-way flow into the first load-sensing multi-way valve and the one-way oil circuit of other actuators, in the rodless chamber of the luffing cylinder On the oil path to the first load-sensing multi-way valve, there is a bypass oil path that flows into the accumulator in one direction, and a switch valve is set on the bypass oil path. The switch valve is disconnected when the luffing cylinder is stretched out, Opens when the luffing cylinder is retracted. In the hydraulic system of the present invention, the valve port flow of the first load-sensing multi-way valve can be provided by the recovered flow together with the output flow of the load-sensing pump, thereby generating energy-saving effects and fully releasing energy.

Description

technical field [0001] The invention relates to the field of hydraulic technology, in particular to a crane and its hydraulic system. Background technique [0002] At present, there are endless methods and ideas for researching energy saving of construction cranes, but they have not solved the impact of energy recovery on the normal operation of the actuator and whether the stored energy can be fully released. For example, in some cranes, the accumulator is directly connected to the rodless cavity of the luffing cylinder. When the weight is placed under the boom, the gravitational potential energy is converted into pressure energy through the accumulator and stored in the accumulator. However, as the internal absorption pressure of the accumulator increases, the falling speed of the luffing cylinder gradually slows down, and the controllability is poor; when the boom is lifted, the pressure energy stored in the accumulator is released to drive the luffing cylinder elongatio...

AI Technical Summary

Problems solved by technology

[0002] At present, there are endless methods and ideas for researching energy saving of engineering cranes, but they have not solved the impact of energy recovery on the normal operation of the actuator and whether the stored energy can be fully released.

For example, in some cranes, the accumulator is directly connected to the rodless cavity of the luffing cylinder. When the weight is placed under the boom, the gravitational potential energy is converted into pressure energy through the accumulator and stored in the accumulator. However, as the internal absorption pressure of the accumulator increases, the falling speed of the luffing cylinder gradually slows down, and the controllability is poor; when the boom is lifted, the pressure energy stored in the accumulator is released to drive the luffing cylinder elongation

However, as the release pressure inside the accumulator decreases, the generated thrust gradually becomes difficult to push the luffing cylinder, which not only causes the movement of the luffing cylinder to be inaccurate, but also causes the energy recovered by the accumulator to not be fully released.

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