Return oil diversion system for telescopic boom oil cylinder of high altitude work vehicle

Abstract

A return oil diversion system for a telescopic boom oil cylinder of a high altitude work vehicle comprises a multiple directional control valve, a balanced control valve and the oil cylinder. A port A of the multiple directional control valve is connected with a rodless cavity oil port C1 of the oil cylinder through the balanced control valve. A port B of the multiple directional control valve is connected with a control end K1 of the balanced control valve and a rod cavity oil port C2 of the oil cylinder simultaneously. The rod cavity oil port C2 of the oil cylinder is also connected with the control end K1 of the balanced control valve. A throttling valve and a balanced oil return valve are further connected between the port A and the port B of the multiple directional control valve in series. A control end K2 of the balanced oil return valve is connected with the port B of the multiple directional control valve. The throttling valve and the balanced oil return valve are both connected with an oil tank through a switching valve. According to the return oil diversion system for the telescopic boom oil cylinder of the high altitude work vehicle, the balanced oil return valve is added between the port A and the port B of the multiple directional control valve, and the throttling valve is added at the port B of the multiple directional control valve for oil return at the same time, so that the purpose of return oil diversion is achieved, and the problems of impact and shaking generated when the oil cylinder starts to retract are solved.

Description

technical field [0001] The invention belongs to the field of hydraulic control, in particular to an oil return and diversion system for a telescopic arm oil cylinder of an aerial work vehicle. Background technique [0002] At present, telescopic arm type aerial work vehicles and truck cranes all use telescopic oil cylinders as executive parts for their telescopic booms, and the sleeves of the booms are driven by the oil cylinders to extend and retract. In order to obtain a larger bearing capacity and enhance the stability of the cylinder, the area ratio of the telescopic arm cylinder (the ratio of the area of ​​the rodless cavity to the area of ​​the rod cavity, assuming N) is relatively large. At the same time, in order to prevent the retraction speed from being too fast and out of control, a balance valve is generally installed in the rodless chamber of the oil cylinder. [0003] The control system of the existing telescopic arm oil cylinder is as follows: figure 1 As sh...

AI Technical Summary

Problems solved by technology

[0005] 1. A large amount of hydraulic oil is returned through the A port of the multi-way directional control valve 1, and the oil return flow rate is greater than the rated flow rate of the multi-way directional control valve 1, so that a large oil return is generated at the A port of the multi-way directional control valve 1. Back pressure, the extra back pressure in this part will cause additional energy loss;

[0006] 2. When a large oil return back pressure is generated at the A port of the multi-way directional valve 1, the pressure of the oil return back pressure will be superimposed on the oil inlet P of the multi-way directional valve 1. When the pressure of the oil inlet P If the setting value of the overflow valve is exceeded, the hydraulic oil entering the oil inlet P of the multi-way reversing valve will overflow through the overflow valve under high pressure, resulting in a large energy loss, resulting in slow retraction of the oil cylinder;

[0007] 3. Because it is necessary to establish the rod cavity pressure of the oil cylinder first, and then the balance valve will switch to open, so when the oil cylinder first retracts, a high-pressure shock will be generated, causing the oil cylinder to shake

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