Balance valve group and hydraulic system

Abstract

The invention discloses a balance valve group and a hydraulic system. The balance valve group comprises a balance valve (100), wherein the balance valve (100) is provided with a first balance valve working port (101) leading to loads, a second balance valve work oil opening (102) leading to an oil source or an oil tank, a balance valve hydraulic control cavity (103) and a balance valve spring cavity (104), and the balance valve hydraulic control cavity (103) and the balance valve spring cavity (104) are located at the two ends of a valve element of the balance valve (100). The balance valve group further comprises a pressure compensation device connected with the balance valve (100). Therefore, when hydraulic oil sequentially passes through the first balance valve work oil opening (101) and the second balance valve work oil opening (102) from the loads and flows back to the oil tank, the pressure difference between the first balance valve work oil opening (101) and the second balance valve work oil opening (102) keeps constant, and the flow amount of the hydraulic oil passing through the balance valve (100) depends on the position of the valve element of the balance valve instead of the pressure of the loads.

Description

Technical field [0001] The present invention relates to hydraulic components, in particular to a balance valve group and hydraulic system. Background technique [0002] The balance valve is a key hydraulic component that controls the luffing action of the truck crane. It is used in the hydraulic system of the luffing mechanism to ensure the smooth operation of the luffing mechanism. figure 1 Shows a schematic diagram of a hydraulic system of a luffing mechanism in the prior art, including a hydraulic cylinder 4 for supporting a luffing boom, a balance valve 100 and a reversing valve 5 connected according to the connection relationship shown in the figure, from figure 1 It can be seen that since the pressure of the balance valve hydraulic control oil circuit 18 corresponding to the balance valve 100 is the same as that of the rod cavity of the hydraulic cylinder 4, the pressure change in the rod cavity of the hydraulic cylinder 4 will directly affect the opening degree of the balanc...

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Problems solved by technology

[0004] The force change of the hydraulic cylinder 4 causes the pressure of the hydraulic oil in the rodless cavity of the hydraulic cylinder 4 to change continuously. Although the opening of the spool of the balance valve 100 is constant, the pressure difference between the front and rear of the throttle port of the balance valve 100 is constantly changing. The flow rate of the luffing drop is also constantly changing, that is, the retraction speed of the hydraulic cylinder 4 is not controlled

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