Multi-oil-cylinder hydraulic control system

Abstract

The utility model relates to a multi-oil-cylinder hydraulic control system which comprises two oil cylinders arranged in a spaced mode. Each oil cylinder is provided with a synchronous control valve group; each synchronous control valve group comprises an oil inlet PE end, an oil return port TE end and a three-way proportional servo valve; a port P and a port T of the three-way proportional servo valve are respectively communicated with an oil inlet PE end and an oil return port TE end, and a port A of the three-way proportional servo valve is communicated with the oil cylinder; and each synchronous control valve group controls the corresponding oil cylinder to perform speed synchronization. The synchronous control valve group solves the problem that redistributed oil cannot be uniformly distributed to each oil cylinder when oil is shared due to the fact that oil channels of the two oil cylinders are connected to a main path in series.

Description

Technical Field

[0001] The utility model belongs to the technical field of hydraulic control, and particularly relates to a multi-cylinder hydraulic control system. Background Art

[0002] In the multi-chamber cylinder system of an offshore workover platform, since the system design is based on the scheme of a single cylinder and is extended by adding circuits to control multiple cylinders. This design results in the fact that in actual operation, the oil passages of two cylinders are connected in series to the main circuit when working, so that the redistributed oil volume during oil sharing cannot be evenly distributed to each cylinder. Each cylinder operates according to its own operating conditions, causing the cylinders to fail to work synchronously, thereby resulting in distortion of the equipment.

[0003] Based on the above problems, the utility model proposes a multi-cylinder hydraulic control system. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a multi-cylinder hydraulic control system. To achieve the above purpose, the technical scheme adopted by the utility model is as follows:

[0005] A multi-cylinder hydraulic control system includes:

[0006] Two cylinders arranged at intervals;

[0007] Each of the cylinders is provided with a synchronous control valve group;

[0008] Each of the synchronous control valve groups includes an oil inlet PE end, an oil return TE end, and a three-way proportional servo valve;

[0009] The P port and the T port of the three-way proportional servo valve are respectively communicated with the oil inlet PE end and the oil return TE end, and the A port of the three-way proportional servo valve is communicated with the cylinder;

[0010] Each of the synchronous control valve groups controls the corresponding cylinder to perform speed synchronization.

[0011] Further, the cylinder includes a first cylindrical cavity with an upper end opening, a second cylindrical cavity with a lower end opening, an inner sleeve, and a central pipe column;

[0012] The inner sleeve and the central pipe column are sequentially sleeved in the first cylindrical cavity, and a first cavity is formed by the inner circumference of the inner sleeve and the outer circumference of the central pipe column in a circumferential sleeve manner;

[0013] The outer circumference of the second cylindrical cavity and the inner circumference of the first cylindrical cavity are circumferentially sleeved to form a D cavity;

[0014] The outer circumference of the inner sleeve and the inner circumference of the second cylindrical cavity are circumferentially sleeved to form a second cavity, and the second cavity is communicated with the first cavity to form a C cavity;

[0015] The central pipe column is provided with a central cavity hole that communicates with the second cylindrical cavity, and the central cavity hole and the second cylindrical cavity form cavity B;

[0016] The second cylindrical cavity is sleeved around the lower ends of the first cylindrical cavity and the inner sleeve, and the second cylindrical cavity, the first cylindrical cavity and the inner sleeve enclose to form cavity A.

[0017] Further, the synchronous control valve group further includes a first two-position two-way directional control valve, a second two-position two-way directional control valve and a three-position four-way directional control valve;

[0018] The B port of the first two-position two-way directional control valve is communicated with the A port of the three-way proportional servo valve, and the A port of the first two-position two-way directional control valve is communicated with the B cavity of the oil cylinder;

[0019] The B port of the second two-position two-way directional control valve is communicated with the TE end of the oil return port, and the A port of the second two-position two-way directional control valve is communicated with the C cavity of the oil cylinder;

[0020] The P port and the T port of the three-position four-way directional control valve are respectively communicated with the PE end of the oil inlet port and the TE end of the oil return port, and the A port of the three-position four-way directional control valve is communicated with the D cavity of the oil cylinder.

[0021] Further, the synchronous control valve group further includes a third two-position two-way directional control valve, the B port of the third two-position two-way directional control valve is communicated with the TE end of the oil return port, and the A port of the third two-position two-way directional control valve is communicated with the B cavity of the oil cylinder.

[0022] Further, the synchronous control valve group further includes a fourth two-position two-way directional control valve, the B port of the fourth two-position two-way directional control valve is communicated with the D cavity of the oil cylinder, and the A port of the fourth two-position two-way directional control valve is communicated with the A cavity of the oil cylinder through the A port of the three-way proportional servo valve.

[0023] Further, the synchronous control valve group further includes a two-position four-way directional control valve, the P port of the two-position four-way directional control valve is communicated with the C cavity of the oil cylinder, the A port of the two-position four-way directional control valve is communicated with the TE end of the oil return port through the B port of the second two-position two-way directional control valve, and the B port of the two-position four-way directional control valve is communicated with the A cavity of the oil cylinder through the A port of the three-way proportional servo valve.

[0024] Further, a balance valve group is further arranged on each oil cylinder, one end of the balance valve group is communicated with the oil cylinder, and the other end thereof is communicated with the PE end of the oil inlet port and the TE end of the oil return port.

[0025] Further, the balance valve group is a proportional balance cartridge valve. The A port of the proportional balance cartridge valve communicates with the A chamber of the oil cylinder. The B port of the proportional balance cartridge valve communicates with the PE end of the oil inlet through the P port of the three-way proportional servo valve, and the B port of the proportional balance cartridge valve communicates with the TE end of the oil return port through the T port of the three-way proportional servo valve.

[0026] Due to the adoption of the above technical solutions, the present utility model has the following advantages:

[0027] Compared with the existing technology, in the multi-oil cylinder hydraulic control system of the present utility model, each oil cylinder is configured with a synchronous control valve group, and each synchronous control valve group adopts an independent circuit, so that under the action conditions of its own, the oil in one oil cylinder flows back to the oil cylinder itself and is not interfered by the oil return of another oil cylinder; the independently arranged synchronous control valve group solves the problem that the oil channels of two oil cylinders are connected in series to the main circuit, resulting in the uneven distribution of the redistributed oil volume to each oil cylinder when the oil is shared. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of the prior art.

[0029] Figure 2 It is a schematic structural diagram of a multi-oil cylinder hydraulic control system of the present utility model.

[0030] Figure 3 It is a schematic structural diagram of the oil cylinder of a multi-oil cylinder hydraulic control system of the present utility model.

[0031] The reference numerals are as follows: 1 - oil cylinder, 101 - first cylindrical cavity, 102 - second cylindrical cavity, 103 - inner sleeve, 104 - central pipe column, 105 - first cavity, 106 - second cavity, 2 - synchronous control valve group, 201 - three-way proportional servo valve, 202 - first two-position two-way directional valve, 203 - second two-position two-way directional valve, 204 - three-position four-way directional valve, 205 - third two-position two-way directional valve, 206 - fourth two-position two-way directional valve, 207 - two-position four-way directional valve, 3 - balance valve group, 301 - proportional balance cartridge valve, 4 - first proportional valve, 5 - second proportional valve, 6 - first electromagnetic directional valve, 7 - second electromagnetic directional valve, 8 - third electromagnetic directional valve, 9 - first oil cylinder, 10 - second oil cylinder. Detailed Embodiments

[0032] The following will describe in detail the preferred embodiments of the present utility model with reference to the drawings, so as to more clearly understand the purpose, features and advantages of the present utility model. It should be understood that the embodiments shown in the drawings are not a limitation to the scope of the present utility model, but only to illustrate the essential spirit of the technical solution of the present utility model.

[0033] AsFigure 1 As shown, the hydraulic system of the existing product is extended based on the single cylinder scheme, and the control of multiple cylinders is realized by adding circuits. The specific design scheme is as follows: The first proportional valve 4 is connected to the A1 chamber of the first cylinder 9 to adjust the lifting speed of the first cylinder 9; the second proportional valve 5 is connected to the A2 chamber of the second cylinder 10 to adjust the lifting speed of the second cylinder 10; the first electromagnetic directional valve 6 is connected to the D1 chamber and D2 chamber of the first cylinder 9 and the second cylinder 10 for the oil inlet, oil return and differential action of the D1 and D2 chambers; the second electromagnetic directional valve 7 is connected to the C1 chamber and C2 chamber of the first cylinder 9 and the second cylinder 10 for the oil inlet, oil return and differential action of the C1 and C2 chambers; the third electromagnetic directional valve 8 is connected to the B1 chamber and B2 chamber of the first cylinder 9 and the second cylinder 10 for the oil inlet, oil return and differential action of the B1 and B2 chambers.

[0034] Since the hydraulic system of the existing product is composed of single cylinder systems spliced together, when the two cylinders are working, the oil channels of the cylinders are connected in series to the main circuit, resulting in the uneven distribution of the reallocated oil volume during oil sharing to each cylinder. Each cylinder operates according to its own operating conditions, causing the problem that the cylinders cannot be synchronized and the equipment is distorted.

[0035] Embodiment 1

[0036] As Figure 2 shown. This embodiment proposes a multi-cylinder hydraulic control system, including two cylinders 1 arranged at intervals; each cylinder 1 is provided with a synchronous control valve group 2; each synchronous control valve group 2 includes an oil inlet PE end, an oil return TE end and a three-way proportional servo valve 201; the P port and T port of the three-way proportional servo valve 201 are respectively communicated with the oil inlet PE end and the oil return TE end, and the A port of the three-way proportional servo valve 201 is communicated with the cylinder, and each synchronous control valve group 2 controls the corresponding cylinder 1 to perform speed synchronization.

[0037] Specifically, the oil cylinder 1 includes a first cylindrical cavity 101 with an upper opening, a second cylindrical cavity 102 with a lower opening, an inner sleeve 103, and a central pipe column 104. An inner sleeve 103 and a central pipe column 104 are sequentially sleeved in the first cylindrical cavity 101. The inner circumference of the inner sleeve 103 and the outer circumference of the central pipe column 104 are sleeved to form a first cavity 105. The outer circumference of the second cylindrical cavity 102 and the inner circumference of the first cylindrical cavity 101 are sleeved to form a D cavity. The inner circumferential surface of the first cylindrical cavity 101, the outer circumferential surface of the second cylindrical cavity 102, and the upper circumferential surface of the flange at the opening of the second cylindrical cavity 102 enclose to form a D cavity. The outer circumference of the inner sleeve 103 and the inner circumference of the second cylindrical cavity 102 are sleeved to form a second cavity 106. The second cavity 106 communicates with the first cavity 105 to form a C cavity. The central pipe column 104 is provided with a central cavity hole that penetrates through the second cylindrical cavity 102. The central cavity hole and the second cylindrical cavity 102 form a B cavity. The second cylindrical cavity 102 is sleeved at the lower ends of the first cylindrical cavity 101 and the inner sleeve 103. The second cylindrical cavity 102, the first cylindrical cavity 101, and the inner sleeve 103 enclose to form an A cavity.

[0038] Specifically, synchronous control valve groups 2 are respectively arranged on the first oil cylinder and the second oil cylinder. The synchronous control valve groups 2 solve the problem that when the oil channels of the oil cylinders are connected in series to the main circuit, the redistributed oil volume during oil sharing cannot be evenly distributed to each oil cylinder. In this embodiment, the accuracy of the three-way proportional servo valve 201 is ±0.1%, which is 10 times higher than the original accuracy, solving the problem of low repeated accuracy of the proportional valve in existing products. The first oil cylinder and the second oil cylinder adopt independent circuits, so that under the action conditions of the oil in the first oil cylinder, the oil inside the oil cylinder flows back to the oil cylinder itself and is not interfered by the oil return of the second oil cylinder. Similarly, under the action conditions of the oil in the second oil cylinder, the oil inside the oil cylinder flows back to the oil cylinder itself and is not interfered by the oil return of the first oil cylinder.

[0039] Specifically, the synchronous control valve group 2 further includes a first two-position two-way reversing valve 202, a second two-position two-way reversing valve 203, and a three-position four-way reversing valve 204. The B port of the first two-position two-way reversing valve 202 is communicated with the A port of the three-way proportional servo valve 201, and the A port of the first two-position two-way reversing valve 202 is communicated with the B cavity of the oil cylinder 1. The pressure oil can pass through the A port of the three-way proportional servo valve 201, pass through the B port of the first two-position two-way reversing valve 202 to the A port, and flow through the EB port into the B cavity of the oil cylinder.

[0040] The B port of the second two-position two-way reversing valve 203 is communicated with the TE end of the oil return port, and the A port of the second two-position two-way reversing valve 203 is communicated with the C cavity of the oil cylinder 1. The pressure oil can flow into the EC port through the orifice of the C cavity of the oil cylinder 1, flow through the P port to the A port of the three-position four-way reversing valve 207, enter the A port to the B port of the second two-position two-way reversing valve 203, and then flow back from the B port to the oil return port TE end of the system.

[0041] The P port and the T port of the three-position four-way directional control valve 204 are respectively connected to the PE end of the oil inlet and the TE end of the oil return port, and the A port of the three-position four-way directional control valve 204 is connected to the D chamber of the oil cylinder 1. The pressure oil enters the P port of the three-position four-way directional control valve 204 through the PE port of the oil inlet and flows to the A port, then flows through the ED port and enters the D chamber of the oil cylinder 1; the pressure oil can also enter the ED port through the port of the D chamber of the oil cylinder 1, flow through the A port of the three-position four-way directional control valve 204 to the T port, and then flow back to the TE end of the oil return port of the system from the T port;

[0042] Further, the pressure oil enters the three-way proportional servo valve 201 through the PE end of the oil inlet, and the three-way proportional servo valve 201 conveys a certain amount of oil to the A chamber of the oil cylinder 1; at the same time, the first two-position two-way directional control valve 202 is opened, and a part of the oil flowing through the A chamber of the oil cylinder is conveyed to the B chamber in equal proportion; the second two-position two-way directional control valve 203 is opened, and the oil in the C chamber of the oil cylinder is guided to the TE end of the oil return port; the three-position four-way directional control valve 204 guides the oil in the D chamber of the oil cylinder to the TE end of the oil return port; in this way, the first-stage speed synchronization of the first oil cylinder and the second oil cylinder can be achieved by controlling the three-way proportional servo valve 201;

[0043] Specifically, the synchronous control valve group 2 further includes a third two-position two-way directional control valve 205. The B port of the third two-position two-way directional control valve 205 is connected to the TE end of the oil return port, and the A port of the third two-position two-way directional control valve 205 is connected to the B chamber of the oil cylinder 1. The pressure oil can enter the EB port through the port of the B chamber of the oil cylinder, flow through the A port of the third two-position two-way directional control valve 205 to the B port, and flow to the TE end of the oil return port to return to the system; the system oil can flow through the B port of the third two-position two-way directional control valve 205 to the A port through the TE end of the oil return port, and flow to the EB port and enter the B chamber of the oil cylinder.

[0044] Further, the pressure oil enters the three-way proportional servo valve 201 through the PE end of the oil inlet, and the three-way proportional servo valve 201 conveys a certain amount of oil to the A chamber of the oil cylinder; at the same time, the third two-position two-way directional control valve 205 is opened, and a part of the oil at the TE end of the oil return port is conveyed to the B chamber of the oil cylinder in equal proportion; the second two-position two-way directional control valve 203 is opened, and the oil in the C chamber of the oil cylinder is guided to the TE end of the oil return port; the three-position four-way directional control valve 204 guides the oil in the D chamber of the oil cylinder to the TE end of the oil return port; in this way, the second-stage speed synchronization of the first oil cylinder and the second oil cylinder can be achieved by controlling the three-way proportional servo valve 201.

[0045] Specifically, the synchronous control valve group 2 further includes a fourth two-position two-way directional valve 206. The B port of the fourth two-position two-way directional valve 206 is communicated with the D chamber of the oil cylinder 1, and the A port of the fourth two-position two-way directional valve 206 is communicated with the A chamber of the oil cylinder 1 through the A port of the three-way proportional servo valve 201. The pressure oil can enter the ED port through the orifice of the D chamber of the oil cylinder, flow through the B port of the fourth two-position two-way directional valve 206 to the A port, merge with the oil from the A port of the three-way proportional servo valve 201, and then flow to the EA port to enter the A chamber of the oil cylinder.

[0046] Further, the pressure oil enters the three-way proportional servo valve 201 through the oil inlet PE port. The three-way proportional servo valve 201 delivers a certain amount of oil to the A chamber of the oil cylinder. At the same time, the third two-position two-way directional valve 205 is opened to proportionally deliver a part of the oil from the oil return port TE to the B chamber of the oil cylinder. The second two-position two-way directional valve 203 is opened to guide the oil in the C chamber of the oil cylinder to the oil return port TE. The fourth two-position two-way directional valve 206 is opened to proportionally guide the oil in the D chamber of the oil cylinder to the rear end of the three-way proportional servo valve 201, and together with the three-way proportional servo valve 201, delivers the oil to the A chamber of the oil cylinder. Due to the characteristics of the oil cylinder itself, the oil in the D chamber of the oil cylinder supplies oil to the A chamber of the oil cylinder at the same ratio as the oil of the three-way proportional servo valve. In this way, only by controlling the oil delivery volume of the three-way proportional servo valve 201, the speed of the oil cylinder can be controlled without being interfered by other external conditions. In this way, the third-level speed synchronization of the first oil cylinder and the second oil cylinder can be achieved by controlling the three-way proportional servo valve 201.

[0047] Specifically, the synchronous control valve group 2 further includes a two-position four-way directional valve 207. The P port of the two-position four-way directional valve 207 is communicated with the C chamber of the oil cylinder 1. The A port of the two-position four-way directional valve 207 is communicated with the oil return port TE through the B port of the second two-position two-way directional valve 203. The B port of the two-position four-way directional valve 207 is communicated with the A chamber of the oil cylinder 1 through the A port of the three-way proportional servo valve 201. The pressure oil can pass through the A port of the three-way proportional servo valve 201, through the B port of the two-position four-way directional valve 207 to the P port, and then flow through the EC port to enter the C chamber of the oil cylinder. The pressure oil can enter the EC port through the orifice of the C chamber of the oil cylinder, flow through the P port of the two-position four-way directional valve 207 to the A port, enter the A port of the second two-position two-way directional valve 203 to the B port, and then flow back from the B port to the oil return port TE of the system. The pressure oil can enter the EC port through the orifice of the C chamber of the oil cylinder, flow through the P port of the two-position four-way directional valve 207 to the B port, merge with the oil from the A port of the three-way proportional servo valve 201, and then flow to the EA port to enter the A chamber of the oil cylinder.

[0048] Further, the pressure oil enters the three-way proportional servo valve 201 from the PE end of the oil inlet. The three-way proportional servo valve 201 delivers a certain amount of oil to the A chamber of the oil cylinder. At the same time, the third two-position two-way directional control valve 205 is opened, and a part of the oil from the TE end of the oil return port is proportionally delivered to the B chamber of the oil cylinder. The two-position two-way directional control valve 207 is opened, and the oil in the C chamber of the oil cylinder is guided to the rear end of the three-way proportional servo valve 201. Together with the three-way proportional servo valve, the oil is delivered to the A chamber of the oil cylinder. The fourth two-position two-way directional control valve 206 is opened, and the oil in the D chamber of the oil cylinder is proportionally guided to the rear end of the three-way proportional servo valve 201. Together with the three-way proportional servo valve, the oil is delivered to the A chamber of the oil cylinder. Due to the characteristics of the oil cylinder itself, the oil in the C chamber and D chamber of the oil cylinder supplies oil to the A chamber of the oil cylinder at the same ratio as the oil of the three-way proportional servo valve. In this way, only by controlling the oil delivery volume of the three-way proportional servo valve, the speed of the oil cylinder can be controlled without being interfered by other external conditions. In this way, the fourth-level speed synchronization of the first oil cylinder and the second oil cylinder can be achieved by controlling the three-way proportional servo valve 201.

[0049] In this embodiment, a synchronous control valve group is adopted, so that the rising synchronous accuracy of the oil cylinder is improved from the original ±20 mm to ±5 mm, meeting the synchronous requirements of the system.

[0050] In the present utility model, by utilizing the characteristics of the multi-chamber oil cylinder that the oil inflow and outflow of each chamber are proportional, the oil in the C chamber and D chamber of the oil cylinder is introduced between the rear end of the three-way proportional servo valve 201 and the A chamber of the oil cylinder. In this way, only by adjusting the proportional opening of the three-way proportional servo valve 201, the operating speed of the oil cylinder can be adjusted proportionally, solving the problem of low control accuracy caused by the large size of the three-way proportional servo valve 201.

[0051] Embodiment 2

[0052] In the prior art, the proportional valve adopted has a repeat accuracy of only ±1%, making it impossible to achieve the synchronization of the two oil cylinders no matter how the electrical control is adjusted. When the two oil cylinders are descending, no load protection is carried out, resulting in one of the oil cylinders stalling due to excessive load during the fall, which further exacerbates the difficulty of synchronization.

[0053] Based on the problems of the proportional valve adopted in the prior art, in Embodiment 2, a balance valve group is arranged on each oil cylinder 1 to solve the problem of the oil cylinder stalling during the descent.

[0054] Specifically, a balance valve group 3 is also provided on each oil cylinder 1. One end of the balance valve group 3 is communicated with the oil cylinder 1, and the other end thereof is communicated with the PE end of the oil inlet and the TE end of the oil return port; the balance valve group 3 is a proportional balance cartridge valve 301. The A port of the proportional balance cartridge valve 301 is communicated with the A chamber of the oil cylinder 1. The B port of the proportional balance cartridge valve 301 is communicated with the PE end of the oil inlet through the P port of the three-way proportional servo valve 201. The B port of the proportional balance cartridge valve 301 is communicated with the TE end of the oil return port through the T port of the three-way proportional servo valve 201.

[0055] In Embodiment 2, the pressure oil enters the P port of the three-way proportional servo valve 201 through the PE end of the oil inlet, flows to the EA port through the A port of the three-way proportional servo valve 201, flows to the GA port and enters the A chamber of the oil cylinder through the B port to the A port of the proportional balance cartridge valve 301; the pressure oil can pass through the port of the A chamber of the oil cylinder through the A port to the B port of the proportional balance cartridge valve 301, flow through the GA port to the EA port, pass through the A port of the three-way proportional servo valve 201 and flow to the T port, and then flow back from the T port to the TE end of the oil return port of the system.

[0056] Furthermore, the pressure oil enters the D chamber of the oil cylinder through the three-position four-way directional control valve 204 at the PE end of the oil inlet. When the oil cylinder descends, through the support of the balance valve group, the descending speed of the oil cylinder is proportional to the opening size of the proportional balance cartridge valve 301. By controlling the proportional balance cartridge valve 301, the descending synchronization of the first oil cylinder and the second oil cylinder is achieved.

[0057] In this embodiment, by adopting the balance valve group, the descending synchronization accuracy is improved from the original ±30 mm to ±6 mm, meeting the synchronization requirements of the system.

[0058] In the present utility model, during the ascending stage of the oil cylinder, the oil in the D chamber of the oil cylinder is introduced into the rear end of the three-way proportional servo valve 201 through the fourth two-position two-way directional control valve 206, and the oil in the C chamber of the oil cylinder is introduced into the rear end of the three-way proportional servo valve 201 through the two-position four-way directional control valve 207, so that the oil in these two chambers no longer enters through the three-way proportional servo valve 201, thereby greatly reducing the size of the three-way proportional servo valve 201, saving the cost of the three-way proportional servo valve 201, and at the same time reducing the cost of electrical control.

Claims

1. A multi-cylinder hydraulic control system, characterized in that: include: At least two oil cylinders (1) arranged at intervals; Each of the oil cylinders (1) is provided with a synchronous control valve group (2); Each of the synchronous control valve groups (2) comprises an oil inlet PE end, an oil return TE end and a three-way proportional servo valve (201); The P port and the T port of the three-way proportional servo valve (201) are respectively connected to the oil inlet PE end and the oil return port TE end, and the A port of the three-way proportional servo valve (201) is connected to the oil cylinder (1); Each of the synchronous control valve groups (2) controls the corresponding oil cylinder (1) to achieve speed synchronization.

2. A multi-cylinder hydraulic control system according to claim 1, characterized in that: The oil cylinder (1) comprises a first cylindrical cavity (101) with an upper opening, a second cylindrical cavity (102) with a lower opening, an inner sleeve (103) and a central pipe column (104); An inner sleeve (103) and a central tube column (104) are sequentially encircled in the first cylindrical cavity (101), and the inner periphery of the inner sleeve (103) and the outer periphery of the central tube column (104) are encircled to form a first cavity (105); The outer periphery of the second cylindrical cavity (102) and the inner periphery of the first cylindrical cavity (101) are annularly sleeved to form a D cavity; The outer periphery of the inner sleeve (103) and the inner periphery of the second cylindrical cavity (102) form a second cavity (106), and the second cavity (106) is connected to the first cavity (105) to form a C cavity; The central tube column (104) is provided with a central cavity hole that penetrates the second cylindrical cavity (102), and the central cavity hole and the second cylindrical cavity (102) form a B cavity; The second cylindrical cavity (102) is sheathed on the lower ends of the first cylindrical cavity (101) and the inner sleeve (103); the second cylindrical cavity (102), the first cylindrical cavity (101) and the inner sleeve (103) together form cavity A.

3. A multi-cylinder hydraulic control system according to claim 2, characterized in that: The synchronous control valve group (2) further comprises a first two-position two-way reversing valve (202), a second two-position two-way reversing valve (203) and a three-position four-way reversing valve (204); The B port of the first two-position two-way reversing valve (202) is in communication with the A port of the three-way proportional servo valve (201), and the A port of the first two-position two-way reversing valve (202) is in communication with the B chamber of the oil cylinder (1); The B port of the second two-position two-way reversing valve (203) is in communication with the oil return port TE, and the A port of the second two-position two-way reversing valve (203) is in communication with the C chamber of the oil cylinder (1); The P port and the T port of the three-position four-way reversing valve (204) are respectively connected to the oil inlet PE end and the oil return port TE end, and the A port of the three-position four-way reversing valve (204) is connected to the D chamber of the oil cylinder (1).

4. A multi-cylinder hydraulic control system according to claim 3, characterized in that: The synchronous control valve group (2) further comprises a third two-position two-way reversing valve (205), wherein the B port of the third two-position two-way reversing valve (205) is connected to the oil return port TE end, and the A port of the third two-position two-way reversing valve (205) is connected to the B chamber of the oil cylinder (1).

5. A multi-cylinder hydraulic control system according to claim 4, characterized in that: The synchronous control valve group (2) further comprises a fourth two-position two-way reversing valve (206), the B port of the fourth two-position two-way reversing valve (206) being connected to the D chamber of the oil cylinder (1), and the A port of the fourth two-position two-way reversing valve (206) being connected to the A chamber of the oil cylinder (1) via the A port of the three-way proportional servo valve (201).

6. A multi-cylinder hydraulic control system according to claim 5, characterized in that: The synchronous control valve group (2) further comprises a two-position four-way reversing valve (207), the P port of the two-position four-way reversing valve (207) being connected to the C chamber of the oil cylinder (1), the A port of the two-position four-way reversing valve (207) being connected to the oil return port TE end via the B port of the second two-position two-way reversing valve (203), and the B port of the two-position four-way reversing valve (207) being connected to the A chamber of the oil cylinder (1) via the A port of the three-way proportional servo valve (201).

7. A multi-cylinder hydraulic control system according to claim 1, characterized in that: Each oil cylinder (1) is also provided with a balancing valve group (3), one end of which is in communication with the oil cylinder (1), and the other end of which is in communication with the oil inlet PE and the oil return TE.

8. A multi-cylinder hydraulic control system according to claim 7, characterized in that: The balancing valve group (3) is a proportional balancing cartridge valve (301), the A port of the proportional balancing cartridge valve (301) is connected to the A chamber of the oil cylinder (1), the B port of the proportional balancing cartridge valve (301) is connected to the oil inlet PE end via the P port of the three-way proportional servo valve (201), and the B port of the proportional balancing cartridge valve (301) is connected to the oil return port TE end via the T port of the three-way proportional servo valve (201).

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