Double-piston three-cavity stroke-adjustable oil cylinder

Abstract

The utility model discloses a double-piston three-cavity stroke-adjustable oil cylinder which comprises a cylinder barrel, a first piston, a second piston and a piston rod. The first piston and the second piston are slidably connected into the cylinder barrel, a first oil cavity is defined by the first piston and the inner wall of the first end of the cylinder barrel, a second oil cavity is defined by the first piston and the second piston, and a third oil cavity is defined by the second piston and the inner wall of the second end of the cylinder barrel. The first end of the piston rod is fixedly connected with the first piston, the second end of the piston rod penetrates through the second piston and the second end of the cylinder barrel and then is located outside the cylinder barrel, and the second piston is in sliding fit with the piston rod. The hydraulic control device is applied to the field of hydraulic elements, reduces the stroke of the oil cylinder through a hydraulic mode on the premise that the oil cylinder does not need to be disassembled and assembled, is simple and convenient in operation process and high in automation degree, and can adjust and move the position of the piston in real time, flexibly change the stroke of the oil cylinder and meet complex action requirements.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic component technology, specifically a double-piston, three-chamber adjustable-stroke hydraulic cylinder. Background Technology

[0002] Hydraulic cylinders (hereinafter referred to as "cylinders") are common hydraulic system actuators, widely used in the motion execution of various engineering machinery and vehicles. In recent years, the cylinder industry has shown a development trend of intelligence, lightweighting, and integration, moving towards high pressure, high efficiency, and environmental protection. The working performance of cylinders is directly related to the construction efficiency on site, therefore, cylinders with integrated performance are favored by major manufacturers.

[0003] The working principle of a hydraulic cylinder is to convert the pressure energy in hydraulic oil into mechanical energy that pushes the piston rod of the cylinder to move, thereby achieving a variety of functions.

[0004] The outward extension of the piston rod in a hydraulic cylinder is primarily achieved by pressurized oil transmitted from a hydraulic pump into the rodless chamber of the cylinder. This oil pushes the piston, causing the piston rod to move linearly. The piston can stop moving at any time before reaching the limit structure inside the cylinder. The linear distance the cylinder travels from its initial position to the limit mechanism is called the cylinder stroke, which is one of the important performance parameters when selecting a hydraulic cylinder.

[0005] In existing technologies, most hydraulic cylinders have a fixed stroke. When the piston rod moves within the stroke range, it is impossible to measure accurately, and the measurement must be done by visual observation or manual measurement, which has a large error and is dangerous. Furthermore, hydraulic cylinders with fixed strokes have certain limitations for mainframes that can perform complex movements. The few hydraulic cylinders with adjustable strokes are mainly based on mechanical methods, using manual adjustment of the initial position of the piston rod to adjust the cylinder stroke. This method is inefficient and difficult to operate. Utility Model Content

[0006] To address the shortcomings of the existing technology, this utility model provides a dual-piston, three-chamber adjustable hydraulic cylinder that allows for hydraulic control of the cylinder stroke without disassembly, and the operation process is simple.

[0007] To achieve the above objectives, this utility model provides a double-piston three-chamber adjustable hydraulic cylinder, including a cylinder barrel, a first piston, a second piston, and a piston rod;

[0008] The inner wall of the cylinder is provided with two limiting structures spaced apart along the axial direction. The first piston and the second piston are slidably connected inside the cylinder, and the first piston and the second piston are located between the two limiting structures.

[0009] The first oil cavity is formed between the first piston and the inner wall of the first end of the cylinder, the second oil cavity is formed between the first piston and the second piston, and the third oil cavity is formed between the second piston and the inner wall of the second end of the cylinder.

[0010] The first end of the piston rod is fixedly connected with the first piston, the second end of the piston rod passes through the second piston and the second end of the cylinder and is located outside the cylinder, and the second piston is in sliding fit with the piston rod.

[0011] In one of the embodiments, the double-piston three-cavity stroke-adjustable oil cylinder further comprises a first oil path, a second oil path and a third oil path.

[0012] The first oil path is arranged on the cylinder, and a first end thereof is in communication with the first oil cavity and a second end thereof is in communication with an external oil tank through a hydraulic system.

[0013] The second oil path is arranged on the cylinder or the piston rod, and a first end thereof is in communication with the second oil cavity and a second end thereof is in communication with the external oil tank through the hydraulic system.

[0014] The third oil path is arranged on the cylinder, and a first end thereof is in communication with the third oil cavity and a second end thereof is in communication with the external oil tank through the hydraulic system.

[0015] In one of the embodiments, the two limiting structures are located between the first oil path and the third oil path.

[0016] In one of the embodiments, when the second oil path is arranged on the piston rod, a first end of the second oil path is arranged on the piston rod.

[0017] In one of the embodiments, when the second oil path is arranged on the piston rod, a first end of the second oil path is arranged on the first piston.

[0018] In one of the embodiments, the number of the first oil path and the third oil path is two.

[0019] In one of the embodiments, the hydraulic system comprises a three-position four-way electromagnetic valve, a normally open two-position four-way electromagnetic valve and a five-position five-way electromagnetic valve.

[0020] A P port of the three-position four-way electromagnetic valve is in communication with the oil tank through a first pipeline, and a T port of the three-position four-way electromagnetic valve is in communication with the oil tank through a second pipeline.

[0021] A P port of the normally open two-position four-way electromagnetic valve is connected with an A port of the three-position four-way electromagnetic valve through a third pipeline, and a T port of the normally open two-position four-way electromagnetic valve is connected with a B port of the three-position four-way electromagnetic valve through a fourth pipeline.

[0022] The A port of the normally open two-position four-way electromagnetic valve is connected with the second end of the first oil path through a fifth pipeline, and the B port of the normally open two-position four-way electromagnetic valve is connected with the second end of the third oil path through a sixth pipeline;

[0023] The P port of the five-position five-way electromagnetic valve is communicated with an oil tank through a seventh pipeline, and the T port of the five-position five-way electromagnetic valve is communicated with the oil tank through an eighth pipeline;

[0024] The A port of the five-position five-way electromagnetic valve is connected with the second end of the first oil path through a ninth pipeline, the B port of the five-position five-way electromagnetic valve is connected with the second end of the second oil path through a tenth pipeline, and the C port of the five-position five-way electromagnetic valve is connected with the second end of the third oil path through an eleventh pipeline.

[0025] In one of the embodiments, the hydraulic system further comprises a first fixed displacement pump arranged on the first pipeline.

[0026] In one of the embodiments, the hydraulic system further comprises a second fixed displacement pump arranged on the seventh pipeline.

[0027] In one of the embodiments, the hydraulic system further comprises an overflow valve arranged on the first pipeline.

[0028] Compared with the prior art, the utility model has the following beneficial technical effects:

[0029] 1. The double-piston three-cavity stroke-adjustable oil cylinder in the utility model can adjust the stroke of the oil cylinder through the hydraulic mode without disassembling the oil cylinder, which is not only simple in operation process, but also high in automation degree, can adjust the position of the moving piston in real time, flexibly changes the stroke of the oil cylinder, and meets the complex action demand.

[0030] 2. The double-piston three-cavity stroke-adjustable oil cylinder in the utility model precisely controls the piston movement through the hydraulic system in the preferred scheme, can effectively reduce the hydraulic impact, noise and mechanical loss when the oil cylinder is adjusted in stroke, and significantly improves the system stability and service life. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or the prior art description, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can be obtained from the structure shown in the drawings without creative labor.

[0032] Figure 1 It is a schematic view of the first embodiment of the oil cylinder in the embodiments of the utility model;

[0033] Figure 2 It is the second kind of embodiment schematic view of the oil cylinder in the utility model embodiment;

[0034] Figure 3 It is the third kind of embodiment schematic view of the oil cylinder in the utility model embodiment;

[0035] Figure 4 It is the fourth kind of embodiment schematic view of the oil cylinder in the utility model embodiment;

[0036] Figure 5 It is the structure schematic view of the hydraulic system in the utility model embodiment.

[0037] The drawing reference: cylinder 1, first piston 2, second piston 3, piston rod 4, limit structure 5, first oil cavity 6, second oil cavity 7, third oil cavity 8, first oil circuit 9, second oil circuit 10, third oil circuit 11, three-position four-way electromagnetic valve 12, normally open two-position four-way electromagnetic valve 13, five-position five-way electromagnetic valve 14, first constant delivery pump 15, second constant delivery pump 16, overflow valve 17, motor 18, oil tank 19, first pipeline 20, second pipeline 21, third pipeline 22, fourth pipeline 23, fifth pipeline 24, sixth pipeline 25, seventh pipeline 26, eighth pipeline 27, ninth pipeline 28, tenth pipeline 29, eleventh pipeline 30.

[0038] The realization, functional characteristics and advantages of the utility model will be further described with reference to the drawings. Specific implementation

[0039] The technical scheme in the utility model embodiment will be clearly and completely described below with reference to the drawings in the utility model embodiment, obviously, the described embodiment is only a part of the embodiment of the utility model, not all the embodiment. Based on the embodiment in the utility model, all other embodiments obtained by the person skilled in the art without making creative labor belong to the scope of the utility model protection.

[0040] It should be noted that all directionality indications (such as up, down, left, right, front, back...) in the utility model embodiment are only used to explain the relative position relationship, movement condition and the like between components in a certain specific posture (as shown in the drawings), if the specific posture changes, then the directionality indication also changes accordingly.

[0041] In addition, the description of "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the technical features or implicitly indicating the number of the technical features indicated. Therefore, the features limited by "first" and "second" can be explicitly or implicitly included at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0042] In the present application, unless otherwise specifically defined and limited, the terms "connection", "fixing" and the like should be broadly understood, for example, "fixing" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection, or physical connection or wireless communication connection; can be directly connected, or indirectly connected through intermediate medium, can be the internal communication of two elements or the interaction relationship of two elements, unless otherwise specifically limited. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0043] In addition, the technical solutions of each embodiment of the present application can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, also not within the protection scope required by the present application.

[0044] As Figure 1 As shown is a kind of double piston three cavity stroke adjustable oil cylinder (hereinafter referred to as "oil cylinder") disclosed in the present embodiment, it mainly includes cylinder 1, first piston 2, second piston 3 and piston rod 4. Wherein, two limit structures 5 are provided on the inner wall of cylinder 1 along the axial direction, first piston 2 and second piston 3 are slidingly connected in cylinder 1. The first oil cavity 6 is formed between the first piston 2 and the inner wall of the first end of the cylinder 1, the second oil cavity 7 is formed between the first piston 2 and the second piston 3, and the third oil cavity 8 is formed between the second piston 3 and the inner wall of the second end of the cylinder 1. First piston 2 and second piston 3 are located between two limit structures 5, i.e. the left limit structure 5 is always located in the first oil cavity 6, and the right limit structure 5 is always located in the third oil cavity 8.

[0045] The first end of the piston rod 4 is fixedly connected with the first piston 2 by a mechanical fixing mode such as a set screw, and the second end of the piston rod 4 passes through the second piston 3 and the second end of the cylinder barrel 1 in sequence and is located outside the cylinder barrel 1, and the second piston 3 is in sliding fit with the piston rod 4, that is, when the first piston 2 and the piston rod 4 are static, the second piston 3 can slide independently. When the second piston 3 slides independently to increase the distance between the first piston 2 and the second piston 3, the stroke of the oil cylinder is correspondingly reduced. When the second piston 3 slides independently to reduce the distance between the first piston 2 and the second piston 3, the stroke of the oil cylinder is correspondingly increased.

[0046] In the specific implementation process, the oil cylinder further comprises a first oil path 9, a second oil path 10 and a third oil path 11. Specifically, the first oil path 9 is arranged on the cylinder barrel 1, and a first end thereof is in communication with the first oil chamber 6, and a second end thereof is in communication with an external oil tank 19 through a hydraulic system. The second oil path 10 is arranged on the cylinder barrel 1 or the piston rod 4, and a first end thereof is in communication with the second oil chamber 7, and a second end thereof is in communication with the external oil tank 19 through the hydraulic system. The third oil path 11 is arranged on the cylinder barrel 1, and a first end thereof is in communication with the third oil chamber 8, and a second end thereof is in communication with the external oil tank 19 through the hydraulic system. The two limiting structures 5 are located between the first oil path 9 and the third oil path 11, so that the first oil path 9 and the first oil chamber 6 are always in communication, and the third oil path 11 and the third oil chamber 8 are always in communication during the sliding process of the first piston 2 and the second piston 3.

[0047] In the specific implementation process, when the second oil path 10 is arranged on the piston rod 4, the first end of the second oil path 10 can be arranged on the piston rod 4 as shown in Figure 1 , or the first end of the second oil path 10 can be arranged on the first piston 2 as shown in Figure 2 . It is worth noting that although the first end of the second oil path 10 can be arranged on the cylinder barrel 1 as shown in Figure 3 , the position thereof needs to be specifically designed to prevent the second oil path 10 from no longer being in communication with the second oil path 10 with the sliding of the first piston 2 and the second piston 3.

[0048] In the specific application process, the number of the first oil path 9 and the third oil path 11 can also be set to two. For example, the oil cylinder is changed into a double-piston three-chamber five-oil-port oil cylinder as shown in Figure 4 , but the risk of oil leakage and inaccurate stroke of the oil cylinder is larger. Therefore, the oil cylinder in the embodiment preferably adopts the implementation mode as shown in Figure 1 , Figure 2 .

[0049] Taking the oil cylinder implementation mode as shown in Figure 1 , Figure 2 , the principle of stroke adjustment of the oil cylinder in the embodiment is specifically as follows:

[0050] Step 1, the first oil cavity 6 is connected to high pressure oil, the third oil cavity 8 is connected to the oil tank 19, and the second oil cavity 7 is not connected to oil and is used to transfer pressure, at this time, the first piston 2, the piston rod 4 and the second piston 3 move synchronously, and the piston rod 4 moves to the right;

[0051] Step 2, the second oil cavity 7 is connected to high pressure oil, the third oil cavity 8 is connected to the oil tank 19, at this time, the piston rod 4 does not move, and the second piston 3 moves to the right;

[0052] Step 3, after the second oil cavity 7 is cut off to supply oil and the third oil cavity 8 is cut off to return oil, the first oil cavity 6 is supplied with high pressure oil again, the third oil cavity 8 is connected to the oil tank 19, and the piston rod 4 moves to the right again, it is worth noting that, at this time, because the second piston 3 moves to the right by a distance in step 2, the second piston 3 is closer to the right limiting structure 5, so compared with the stroke of the oil cylinder in step 1, the stroke of the oil cylinder at this time is reduced to a certain extent;

[0053] Step 4, after the first oil cavity 6 of the oil cylinder is cut off to supply high pressure oil again, the first piston 2, the piston rod 4 and the second piston 3 stop moving;

[0054] Step 5, the second oil cavity 7 is connected to the oil tank 19, and the third oil cavity 8 is supplied with high pressure oil, at this time, the piston rod 4 does not move, and the second piston 3 moves to the left;

[0055] Step 6, after the second oil cavity 7 is cut off to return oil and the third oil cavity 8 is cut off to supply oil, the first oil cavity 6 is supplied with high pressure oil again, the third oil cavity 8 is connected to the oil tank 19, and the piston rod 4 moves to the right, at this time, because the second piston 3 moves to the left by a distance in step 5, the second piston 3 is farther away from the right limiting structure 5, so compared with the stroke of the oil cylinder in step 4, the stroke of the oil cylinder at this time is increased to a certain extent.

[0056] Similarly, when the piston rod 4 moves to the left to retract, the first oil cavity 6 is cut off to return oil and the third oil cavity 8 is supplied with high pressure oil first, and then the piston rod 4 stops moving. Then the first oil cavity 6 is connected to the oil tank 19 and the second oil cavity 7 is supplied with high pressure oil, or the first oil cavity 6 is supplied with high pressure oil and the second oil cavity 7 is connected to the oil tank 19, so that the first piston 2 is away from or close to the left limiting structure 5, thereby controlling the stroke of the oil cylinder.

[0057] It should be noted that when the piston rod 4 moves in one direction X, the oil supply and return is cut off before reaching the limit structure 5, the stroke of the oil cylinder is adjusted, and then the piston rod 4 moves in the other direction Y. At this time, the stroke of the oil cylinder will still change, but the remaining stroke of the piston rod 4 in the other direction will not change. Therefore, only when the piston rod 4 moves to the limit structure 5 in the direction Y and the pressure is built up, and then moves in the direction X, the stroke of the oil cylinder will increase or decrease. Therefore, in specific applications, the movement of the piston between the second oil chamber 7 and the low-pressure oil chamber (the oil chamber connected to the oil tank 19 when the piston moves) is adjusted as much as possible, so that the pressure of the high-pressure chamber is built up to prevent the oil cylinder from extending or retracting abnormally and uncontrollably. One of the directions X and Y is the left direction in Figure 1 、 Figure 2 , and the other is the right direction in Figure 1 、 Figure 2 .

[0058] Referring to Figure 5 , the hydraulic system includes a three-position four-way electromagnetic valve 12, a normally open two-position four-way electromagnetic valve 13, a five-position five-way electromagnetic valve 14, a first constant pump 15, a second constant pump 16, a relief valve 17, and a motor 18. Specifically:

[0059] The P port of the three-position four-way electromagnetic valve 12 is connected to the oil tank 19 through a first pipeline 20, the T port of the three-position four-way electromagnetic valve 12 is connected to the oil tank 19 through a second pipeline 21, the first constant pump 15 is arranged on the first pipeline 20, the relief valve 17 is connected between the first pipeline 20 and the oil tank 19, and the motor 18 is drivingly connected to the first constant pump 15;

[0060] The P port of the three-position four-way electromagnetic valve 12 is connected to the oil tank 19 through a first pipeline 20, the T port of the three-position four-way electromagnetic valve 12 is connected to the oil tank 19 through a second pipeline 21, the first constant pump 15 is arranged on the first pipeline 20, the relief valve 17 is connected between the first pipeline 20 and the oil tank 19, and the motor 18 is drivingly connected to the first constant pump 15;

[0061] The A port of the normally open two-position four-way electromagnetic valve 13 is connected to the second end of the first oil way 9 through a fifth pipeline 24, and the B port of the normally open two-position four-way electromagnetic valve 13 is connected to the second end of the third oil way 11 through a sixth pipeline 25;

[0062] The P port of the five-position five-way electromagnetic valve 14 is connected to the oil tank 19 through a seventh pipeline 26, the T port of the five-position five-way electromagnetic valve 14 is connected to the oil tank 19 through an eighth pipeline 27, the second constant pump 16 is arranged on the seventh pipeline 26, and the motor 18 is drivingly connected to the second constant pump 16;

[0063] The A port of the five-position five-way electromagnetic valve 14 is connected to the second end of the first oil path 9 through the ninth pipeline 28, the B port of the five-position five-way electromagnetic valve 14 is connected to the second end of the second oil path 10 through the tenth pipeline 29, and the C port of the five-position five-way electromagnetic valve 14 is connected to the second end of the third oil path 11 through the eleventh pipeline 30.

[0064] The specific process of the hydraulic system in the embodiment for hydraulic control of the oil cylinder is as follows:

[0065] When the oil cylinder is in the initial state, all the electromagnets in the three-position four-way electromagnetic valve 12, the normally open two-position four-way electromagnetic valve 13 and the five-position five-way electromagnetic valve 14 are not powered, the three-position four-way electromagnetic valve 12, the normally open two-position four-way electromagnetic valve 13 and the five-position five-way electromagnetic valve 14 are all in the neutral position, and the piston rod 4 does not move at this time.

[0066] When the oil cylinder is in the normal movement state, the three-position four-way electromagnetic valve 12 is powered, and the movement of the oil cylinder to the right or to the left can be controlled.

[0067] When the oil cylinder is in the stroke adjustment state, the electromagnet of the normally open two-position four-way electromagnetic valve 13 is powered, the piston rod 4 stops moving, and the power supply of the electromagnets a, b, c and d of the five-position five-way electromagnetic valve 14 can be controlled to adjust the stroke of the oil cylinder to increase or decrease, for example:

[0068] The electromagnet a of the three-position four-way electromagnetic valve 12 is powered, the piston rod 4 of the oil cylinder moves to the right, and then the electromagnet of the normally open two-position four-way electromagnetic valve 13 is powered, and the piston rod 4 stops moving.

[0069] If the electromagnet a of the five-position five-way electromagnetic valve 14 is powered, high-pressure oil flows from the P port to the B port of the five-position five-way electromagnetic valve 14, enters the second oil chamber 7, and forms a high-pressure chamber in the second oil chamber 7; the third oil chamber 8 is connected to the C port to the T port of the five-position five-way electromagnetic valve 14, thereby connected to the oil tank 19, and forms a low-pressure chamber. Thus, the moving piston is pushed to move to the right, achieving the purpose of reducing the stroke.

[0070] Similarly, if the electromagnets a and c of the five-position five-way electromagnetic valve 14 are powered at the same time, high-pressure oil flows from the P port to the C port of the five-position five-way electromagnetic valve 14, enters the third oil chamber 8, and forms a high-pressure chamber in the third oil chamber 8; the second oil chamber 7 is connected to the B port to the T port of the five-position five-way electromagnetic valve 14, thereby connected to the oil tank 19, and forms a low-pressure chamber. Thus, the moving piston is pushed to move to the left, achieving the purpose of increasing the stroke.

[0071] As a preferred implementation, a flow meter can be externally connected to the second oil chamber 7, and then the inflow and outflow of the second oil chamber 7 can be detected in real time, the volume of the second oil chamber 7 can be calculated, and the distance between the first piston 2 and the second piston 3 can be obtained, compared with the initial distance between the first piston 2 and the second piston 3, and then the oil cylinder stroke range and the remaining movable stroke at this time can be detected in real time.

[0072] The above only describes the preferred embodiments of the utility model, and does not limit the patent range of the utility model, and any equivalent structural transformation made by using the utility model specification and the attached drawings, or direct / indirect application in other related technical fields under the utility model concept of the utility model is included in the patent protection range of the utility model.

Claims

1. A double-piston, three-chamber, stroke-adjustable hydraulic cylinder, characterized in that, Includes cylinder, first piston, second piston and piston rod; The inner wall of the cylinder is provided with two limiting structures spaced apart along the axial direction. The first piston and the second piston are slidably connected inside the cylinder, and the first piston and the second piston are located between the two limiting structures. The first piston and the inner wall of the first end of the cylinder form a first oil chamber, the first piston and the second piston form a second oil chamber, and the second piston and the inner wall of the second end of the cylinder form a third oil chamber. The first end of the piston rod is fixedly connected to the first piston, and the second end of the piston rod passes through the second piston and the second end of the cylinder and is located outside the cylinder. The second piston and the piston rod are in sliding engagement.

2. The dual-piston, three-chamber adjustable hydraulic cylinder according to claim 1, characterized in that, It also includes the first oil circuit, the second oil circuit, and the third oil circuit; The first oil circuit is located on the cylinder, and its first end is connected to the first oil chamber, while its second end is connected to an external oil tank through a hydraulic system. The second oil circuit is located on the cylinder or the piston rod, and its first end is connected to the second oil chamber, while its second end is connected to an external oil tank through a hydraulic system. The third oil circuit is located on the cylinder, with its first end connected to the third oil chamber and its second end connected to an external oil tank via a hydraulic system.

3. The dual-piston, three-chamber adjustable hydraulic cylinder according to claim 2, characterized in that, The two limiting structures are located between the first oil passage and the third oil passage.

4. The dual-piston, three-chamber adjustable hydraulic cylinder according to claim 2, characterized in that, When the second oil passage is located on the piston rod, the first end of the second oil passage is located on the piston rod.

5. The dual-piston, three-chamber adjustable hydraulic cylinder according to claim 2, characterized in that, When the second oil passage is located on the piston rod, the first end of the second oil passage is located on the first piston.

6. The dual-piston three-chamber adjustable hydraulic cylinder according to any one of claims 2 to 5, characterized in that, There are two of each of the first oil circuit and the third oil circuit.

7. The dual-piston, three-chamber adjustable hydraulic cylinder according to any one of claims 2 to 5, characterized in that, The hydraulic system includes a three-position four-way solenoid valve, a normally open two-position four-way solenoid valve, and a five-position five-way solenoid valve. The P port of the three-position four-way solenoid valve is connected to the oil tank through the first pipeline, and the T port of the three-position four-way solenoid valve is connected to the oil tank through the second pipeline. The P port of the normally open two-position four-way solenoid valve is connected to the A port of the three-position four-way solenoid valve through a third pipeline, and the T port of the normally open two-position four-way solenoid valve is connected to the B port of the three-position four-way solenoid valve through a fourth pipeline. The A port of the normally open two-position four-way solenoid valve is connected to the second end of the first oil circuit through the fifth pipeline, and the B port of the normally open two-position four-way solenoid valve is connected to the second end of the third oil circuit through the sixth pipeline. The P port of the five-position five-way solenoid valve is connected to the oil tank through the seventh pipeline, and the T port of the five-position five-way solenoid valve is connected to the oil tank through the eighth pipeline. The A port of the five-position five-way solenoid valve is connected to the second end of the first oil circuit through the ninth pipeline, the B port of the five-position five-way solenoid valve is connected to the second end of the second oil circuit through the tenth pipeline, and the C port of the five-position five-way solenoid valve is connected to the second end of the third oil circuit through the eleventh pipeline.

8. The dual-piston, three-chamber adjustable hydraulic cylinder according to claim 7, characterized in that, The hydraulic system also includes a first metering pump, which is located on the first pipeline.

9. The dual-piston, three-chamber adjustable hydraulic cylinder according to claim 7, characterized in that, The hydraulic system also includes a second metering pump, which is located on the seventh pipeline.

10. The dual-piston, three-chamber adjustable hydraulic cylinder according to claim 7, characterized in that, The hydraulic system also includes a relief valve, which is located on the first pipeline.

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