Closed hydraulic system of multi-chamber oil cylinder and construction machinery

Abstract

The present invention discloses a multi-chamber oil cylinder closed hydraulic system and construction machinery. The multi-chamber oil cylinder closed hydraulic system includes a hydraulic cylinder and a closed pump. The hydraulic cylinder is a multi-chamber oil cylinder, and the multi-chamber oil cylinder includes a hydraulic cylinder body, an oil inlet connected to the closed pump, and an oil outlet connected to the closed pump. The hydraulic cylinder body includes a rodless chamber and a rod chamber. The cross-sectional area of the rodless chamber connected to the oil inlet is equal to the cross-sectional area of the rod chamber connected to the oil outlet. When the closed hydraulic system and the construction machinery are in use, the closed pump can be used to control the flow direction of the hydraulic oil, and there are no control components such as multi-way valves. When the boom of the construction machinery moves upward, there is no pressure loss generated by the multi-way valve. When the boom of the construction machinery moves downward, the flow direction of the hydraulic oil changes, and the closed pump is converted into a motor, that is, the gravitational potential energy during the boom descent process is converted into the mechanical energy of the closed pump, and the gravitational potential energy is recycled.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic boom energy saving, and particularly relates to a multi-chamber cylinder closed hydraulic system and construction machinery. Background Art

[0002] The lifting and lowering of the boom during the working process of an excavator, a material grabber, etc. are controlled by a boom cylinder. Figure 1 For the structural schematic diagram of the boom hydraulic circuit of existing excavators and material grabbers, please refer to Figure 1 , currently, the boom hydraulic circuit of excavators and material grabbers generally includes a hydraulic pump 1', a multi-way valve 2', a hydraulic cylinder 3' and a holding valve 4'. When the boom rises, the hydraulic oil is pressurized by the hydraulic pump 1' and controlled by the multi-way valve 2' to drive the hydraulic cylinder 3' to act, realizing the rise of the hydraulic cylinder 3'; when the boom descends, the multi-way valve 2' throttles to establish resistance to keep the boom descending smoothly.

[0003] In the existing boom hydraulic circuit of excavators and material grabbers, there is a pressure loss at the multi-way valve during the boom rising process, resulting in energy loss. When the boom descends, the multi-way valve throttles to establish resistance to keep the boom descending smoothly. During the boom descending process, the gravitational potential energy is completely converted into heat, causing energy waste. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-chamber cylinder closed hydraulic system, which does not generate pressure loss during the process of the closed pump driving the piston cylinder of the hydraulic cylinder to move upward, and when the piston rod of the hydraulic cylinder moves downward, the closed pump is converted into a motor condition to recover the gravitational potential energy.

[0005] Another purpose of the present invention is to provide a construction machinery, which does not generate pressure loss when the closed pump drives the boom to rise, and when the boom descends, the closed pump is converted into a motor condition to recover the gravitational potential energy.

[0006] The present invention is realized through the following technical solutions:

[0007] The first aspect of the present invention provides a multi-chamber cylinder closed hydraulic system, including a hydraulic cylinder and a closed pump. The hydraulic cylinder is a multi-chamber cylinder, and the multi-chamber cylinder includes a hydraulic cylinder body, an oil inlet connected to the closed pump, and an oil outlet connected to the closed pump. The hydraulic cylinder body includes a rodless chamber and a rod chamber, and the cross-sectional area of the rodless chamber connected to the oil inlet is equal to the cross-sectional area of the rod chamber connected to the oil outlet.

[0008] For the above multi-chamber cylinder closed hydraulic system, the hydraulic cylinder body includes a first cylinder body, a second cylinder body located inside the first cylinder body, and a piston sleeve assembly;

[0009] The piston sleeve assembly includes a cylindrical first piston rod with an inner cavity, a first piston connected to the first piston rod, a second piston rod connected to the inner cavity of the first piston rod, and a second piston connected to the second piston rod. The first piston rod is nested between the inner wall of the first cylinder block and the outer wall of the second cylinder block, and the second piston rod is disposed inside the second cylinder block.

[0010] The rodless chambers include a first rodless chamber and a second rodless chamber; the rod chambers include a first rod chamber and a second rod chamber. The first piston is used to divide the inner cavity between the inner wall of the first cylinder block and the outer wall of the second cylinder block into the first rodless chamber and the first rod chamber, and the second piston is used to divide the inner cavity of the second cylinder block into the second rodless chamber and the second rod chamber.

[0011] The oil inlet connected to the closed pump is disposed on any one of the first rodless chamber and the second rodless chamber described above, and oil outlets connected to the closed pump are provided on both the first rod chamber and the second rod chamber.

[0012] The cross-sectional area of the rodless chamber provided with the oil inlet is equal to the sum of the cross-sectional areas of the first rod chamber and the second rod chamber.

[0013] The multi-chamber oil cylinder closed hydraulic system described above further includes an accumulator, and an oil port connected to the accumulator is provided on the rodless chamber that does not have the oil inlet installed.

[0014] In the multi-chamber oil cylinder closed hydraulic system described above, the accumulator is used to recover the hydraulic oil in the rodless chamber provided with the oil port when the piston sleeve assembly descends, and the accumulator is also used to release the hydraulic oil to provide auxiliary power for the piston sleeve assembly when the piston sleeve assembly ascends.

[0015] In the multi-chamber oil cylinder closed hydraulic system described above, the second cylinder block is coaxially arranged with the first cylinder block, and the cross-section of the first rodless chamber is circular ring-shaped, and the cross-section of the second rodless chamber is circular.

[0016] In the multi-chamber oil cylinder closed hydraulic system described above, the first piston rod is a cylindrical piston rod with an inner cavity, and the second piston rod is a cylindrical piston rod.

[0017] The multi-chamber oil cylinder closed hydraulic system described above further includes a holding valve, and the holding valve is disposed between the closed pump and the rodless chamber provided with the oil inlet.

[0018] In the multi-chamber oil cylinder closed hydraulic system described above, the closed pump is connected to the engine, and the closed pump is used to drive the engine to rotate when the piston sleeve assembly descends.

[0019] The second aspect of the present invention provides a construction machinery, including the multi-chamber cylinder closed hydraulic system as described above and a boom, wherein the boom is connected to a hydraulic cylinder.

[0020] For the construction machinery as described above, the number of the hydraulic cylinders is an even number, and the hydraulic cylinders are arranged in parallel on the lower side of the boom.

[0021] The technical solution provided by this application can achieve the following beneficial effects:

[0022] The multi-chamber cylinder closed hydraulic system of the present invention mainly involves a hydraulic cylinder and a closed pump; the hydraulic cylinder is a multi-chamber cylinder, and the multi-chamber cylinder includes a hydraulic cylinder body, an oil inlet connected to the closed pump, and an oil outlet connected to the closed pump. The hydraulic cylinder body includes a rodless chamber and a rod chamber; at the same time, this multi-chamber cylinder closed hydraulic system (referred to as the hydraulic system for short) also requires that the cross-sectional area of the rodless chamber connected to the oil inlet is equal to the cross-sectional area of the rod chamber connected to the oil outlet, so as to achieve the same oil inlet and outlet of the hydraulic cylinder body (that is, to achieve a closed hydraulic system); when this hydraulic system is working, the closed pump and the hydraulic cylinder form a closed hydraulic system, and this closed hydraulic system can use the closed pump to control the flow direction of the hydraulic oil, and there are no control components such as multi-way valves. Specifically, when the piston of the hydraulic cylinder moves upward, the hydraulic oil does not pass through the multi-way valve and there is no pressure loss; when the piston of the hydraulic cylinder moves downward, the flow direction of the hydraulic oil changes (the flow direction of the hydraulic oil is opposite to the flow direction of the hydraulic oil when the piston of the hydraulic cylinder moves upward), and at this time, the closed pump is converted into a motor, so that the gravitational potential energy in the downward movement of the piston of the hydraulic cylinder can be converted into the mechanical energy of the closed pump, realizing the recycling of gravitational potential energy.

[0023] The construction machinery of the present invention includes the above multi-chamber cylinder closed hydraulic system. The boom of this construction machinery is connected to the multi-chamber cylinder. The cross-sectional area of the rodless chamber of the multi-chamber cylinder closed hydraulic system (referred to as the hydraulic system for short) connected to the oil inlet is equal to the cross-sectional area of the rod chamber connected to the oil outlet, so as to achieve the same oil inlet and outlet of the hydraulic cylinder body (that is, to achieve a closed hydraulic system). When this hydraulic system is working, the closed pump and the hydraulic cylinder form a closed hydraulic system, and this closed hydraulic system can use the closed pump to control the movement direction of the hydraulic oil, and there are no control components such as multi-way valves. Specifically, when the boom moves upward, the hydraulic oil does not pass through the multi-way valve and there is no pressure loss; when the boom moves downward, the flow direction of the hydraulic oil changes (the flow direction of the hydraulic oil is opposite to the flow direction of the hydraulic oil when the piston of the hydraulic cylinder moves upward), and at this time, the closed pump is converted into a motor, so that the gravitational potential energy in the downward movement of the piston of the hydraulic cylinder can be converted into the mechanical energy of the closed pump, realizing the recycling of gravitational potential energy. Description of the Drawings

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic structural diagram of the boom hydraulic circuit of an existing excavator and a material grabber;

[0026] Figure 2 It is a schematic structural diagram of a multi-chamber cylinder closed hydraulic system provided by an embodiment of the present invention;

[0027] Figure 3 It is a schematic structural diagram of a hydraulic cylinder in the multi-chamber cylinder closed hydraulic system provided by an embodiment of the present invention.

[0028] Explanation of reference numerals:

[0029] 1 - Closed pump;

[0030] 2 - Hydraulic cylinder;

[0031] 3 - Accumulator;

[0032] 4 - Holding valve;

[0033] 21 - First cylinder block;

[0034] 22 - Second cylinder block;

[0035] 23 - First piston rod;

[0036] 24 - Second piston rod;

[0037] 25 - First rodless chamber;

[0038] 26 - Second rodless chamber;

[0039] 27 - First rod chamber;

[0040] 28 - Second rod chamber. Specific embodiments

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0042] In the description of the present invention, it should be understood that the terms "including" and "having" used herein and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units need not be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features.

[0043] The multi-chamber cylinder closed hydraulic system and construction machinery provided by the present invention will be introduced in detail below in conjunction with specific embodiments.

[0044] Embodiment 1:

[0045] Figure 2 It is a schematic structural diagram of the multi-chamber cylinder closed hydraulic system provided by the embodiment of the present invention. Figure 3 It is a schematic structural diagram of the hydraulic cylinder in the multi-chamber cylinder closed hydraulic system provided by the embodiment of the present invention. Please refer to Figure 2 、 3 As shown, this embodiment provides a multi-chamber cylinder closed hydraulic system, including a closed pump 1 and a hydraulic cylinder 2;

[0046] The hydraulic cylinder 2 is a multi-chamber cylinder. The multi-chamber cylinder includes a hydraulic cylinder body, an oil inlet connected to the closed pump, and an oil outlet connected to the closed pump. The hydraulic cylinder body includes a rodless chamber and a rod chamber. The cross-sectional area of the rodless chamber connected to the oil inlet is equal to the cross-sectional area of the rod chamber connected to the oil outlet.

[0047] In this multi-chamber cylinder hydraulic system, the cross-sectional area of the rodless chamber connected to the oil inlet is equal to the cross-sectional area of the rod chamber connected to the oil outlet, realizing the same oil inlet and outlet of the hydraulic cylinder body. When working, the closed pump and the hydraulic cylinder form a closed hydraulic system. This closed hydraulic system can use the closed pump to control the movement direction of the hydraulic oil, and there are no control components such as multi-way valves. When the piston of the hydraulic cylinder moves upward, the hydraulic oil does not pass through the multi-way valve and there is no pressure loss; when the piston of the hydraulic cylinder moves downward, the flow direction of the hydraulic oil changes. At this time, the closed pump is converted into a motor, so that the gravitational potential energy during the downward movement of the piston of the hydraulic cylinder can be converted into the mechanical energy of the closed pump, realizing the recycling of gravitational potential energy.

[0048] Specifically, in this embodiment, the hydraulic cylinder body includes a first cylinder body 21, a second cylinder body 22 located inside the first cylinder body, and a piston sleeve assembly;

[0049] The piston sleeve assembly includes a cylindrical first piston rod 23 with an inner cavity, a first piston connected to the first piston rod 23, a second piston rod 24 connected to the inner cavity of the first piston rod 23, and a second piston connected to the second piston rod 24. The first piston rod 23 is nested between the inner wall of the first cylinder block 21 and the outer wall of the second cylinder block 22, and the second piston rod 24 is arranged inside the second cylinder block 22;

[0050] The rodless chambers include a first rodless chamber 25 and a second rodless chamber 26; the rod chambers include a first rod chamber 27 and a second rod chamber 28. The first piston is used to divide the inner cavity between the inner wall of the first cylinder block 21 and the outer wall of the second cylinder block 22 into a first rodless chamber 25 and a first rod chamber 27, and the second piston is used to divide the inner cavity of the second cylinder block 22 into a second rodless chamber 26 and a second rod chamber 28;

[0051] The oil inlet connected to the closed pump is arranged on any one of the first rodless chamber and the second rodless chamber, and oil outlets connected to the closed pump 1 are opened on both the first rod chamber 27 and the second rod chamber 28. In this embodiment, the oil inlet is opened on the first rodless chamber 25, and the cross-sectional area of the first rodless chamber 25 is equal to the sum of the cross-sectional areas of the first rod chamber 27 and the second rod chamber 28;

[0052] In other embodiments, the oil inlet can also be opened on the second rodless chamber 26. At this time, the cross-sectional area of the second rodless chamber 26 is equal to the sum of the cross-sectional areas of the first rod chamber 27 and the second rod chamber 28 to achieve this.

[0053] In this embodiment, by setting the cross-sectional area of the first rodless chamber 25 to be equal to the sum of the cross-sectional areas of the first rod chamber 27 and the second rod chamber 28, the same amount of oil is fed into and discharged from the hydraulic cylinder, thereby realizing a closed hydraulic system. When the piston of the hydraulic cylinder moves upward, the hydraulic oil does not pass through the multi-way valve and no pressure loss occurs; when the piston of the hydraulic cylinder moves downward, the flow direction of the hydraulic oil changes. At this time, the closed pump is converted into a motor, so that the gravitational potential energy during the downward movement of the piston of the hydraulic cylinder can be converted into the mechanical energy of the closed pump, realizing the recycling of gravitational potential energy.

[0054] Furthermore, in this embodiment, the second cylinder block 22 and the first cylinder block 21 are coaxially arranged (that is, the central axes of the above-mentioned first cylinder block 21 and the second cylinder block 22 should be coaxial. In a specific embodiment, the first cylinder block 21 and the second cylinder block 22 are preferably cylindrical cylinder blocks). The cross-section of the first rodless chamber 25 is circular ring-shaped, and the cross-section of the second rodless chamber 26 is circular. The cylinder block with the above structural design is simple and convenient to manufacture.

[0055] Further, in this embodiment, the closed pump 1 is connected to the engine, and the closed pump 1 is used to drive the engine to rotate when the piston sleeve assembly of the hydraulic cylinder descends. By connecting the closed pump 1 to the engine, the mechanical energy when the piston sleeve assembly of the hydraulic cylinder descends is recycled.

[0056] Further, the multi-chamber cylinder closed hydraulic system of this embodiment further includes an accumulator 3. The oil inlet connected to the closed pump is provided on any one of the first rodless chamber 25 and the second rodless chamber 26, and an oil port connected to the accumulator is provided on the rodless chamber without the installation of the oil inlet. That is, when the oil inlet is provided on the first rodless chamber 25 and the cross-sectional area of the first rodless chamber 25 is equal to the sum of the cross-sectional areas of the first rod chamber 27 and the second rod chamber 28, an oil port connected to the accumulator 3 is provided on the second rodless chamber 26 at this time; that is, when the oil inlet is provided on the second rodless chamber 26 and the cross-sectional area of the second rodless chamber 26 is equal to the sum of the cross-sectional areas of the first rod chamber 27 and the second rod chamber 28, an oil port connected to the accumulator 3 is provided on the first rodless chamber 25 at this time.

[0057] The accumulator 3 is used to recover the hydraulic oil in the second rodless chamber 26 or the first rodless chamber 25 when the piston sleeve assembly of the hydraulic cylinder descends to store a part of the hydraulic energy. The accumulator 3 is also used to release the above hydraulic energy to provide auxiliary power for the ascending movement of the piston rod assembly of the hydraulic cylinder when the piston sleeve assembly of the hydraulic cylinder ascends. In this embodiment, by setting the accumulator, the second rodless chamber 26 of the hydraulic cylinder 2 and the accumulator 3 form an energy recovery device. When the piston sleeve assembly descends, the accumulator 3 recovers energy, and when the piston sleeve assembly ascends, it provides auxiliary power, further reducing energy consumption.

[0058] Further, the multi-chamber cylinder closed hydraulic system of this embodiment further includes a holding valve 4, and the holding valve 4 is arranged between the closed pump 1 and the rodless chamber provided with the oil inlet; there are two specific embodiments. That is, when the oil inlet is provided on the first rodless chamber and the cross-sectional area of the first rodless chamber 25 is equal to the sum of the cross-sectional areas of the first rod chamber 27 and the second rod chamber 28, the holding valve 4 is specifically installed on the oil path between the closed pump 1 and the first rodless chamber 25; in other embodiments, that is, when the oil inlet is provided on the second rodless chamber 26 and the cross-sectional area of the second rodless chamber 26 is equal to the sum of the cross-sectional areas of the first rod chamber 27 and the second rod chamber 28, the holding valve is specifically installed on the oil path between the closed pump 1 and the second rodless chamber 26. In this embodiment, by setting the holding valve 4 to maintain the pressure of the hydraulic cylinder, it is prevented that the piston sleeve assembly descends and causes danger when the multi-chamber cylinder closed hydraulic system is in use.

[0059] In the multi-chamber oil cylinder closed hydraulic system of the present invention, the cross-sectional area of the rodless chamber of the hydraulic cylinder connected to the oil inlet is equal to the sum of the cross-sectional areas of the first rod chamber and the second rod chamber. When the hydraulic system is working, the closed pump and the hydraulic cylinder form a closed hydraulic system. When the piston of the hydraulic cylinder moves upward, the hydraulic oil does not pass through the multi-way valve and no pressure loss occurs; when the piston of the hydraulic cylinder moves downward, the flow direction of the hydraulic oil changes (the flow direction of the hydraulic oil is opposite to the flow direction of the hydraulic oil when the piston of the hydraulic cylinder moves upward). At this time, the closed pump is converted into a motor, so that the gravitational potential energy during the downward movement of the piston of the hydraulic cylinder can be converted into the mechanical energy of the closed pump, realizing the recycling of gravitational potential energy.

[0060] Embodiment 2:

[0061] This embodiment provides a construction machinery, which includes the multi-chamber oil cylinder closed hydraulic system described in Embodiment 1 and a boom, and the boom is connected to the hydraulic cylinder.

[0062] For example, a multi-chamber oil cylinder closed hydraulic system includes a hydraulic cylinder and a closed pump;

[0063] The hydraulic cylinder includes a hydraulic cylinder body, an oil inlet connected to the closed pump, and an oil outlet connected to the closed pump. The hydraulic cylinder body includes a rodless chamber and a rod chamber, and the cross-sectional area of the rodless chamber connected to the oil inlet is equal to the cross-sectional area of the rod chamber connected to the oil outlet.

[0064] In this embodiment, the hydraulic cylinder body includes a first cylinder body, a second cylinder body located inside the first cylinder body, and a piston sleeve assembly;

[0065] The piston sleeve assembly includes a tubular first piston rod with an inner cavity, a first piston connected to the first piston rod, a second piston rod connected to the inner cavity of the first piston rod, and a second piston connected to the second piston rod. The first piston rod is nested between the inner wall of the first cylinder body and the outer wall of the second cylinder body, and the second piston rod is arranged inside the second cylinder body;

[0066] The rodless chamber includes a first rodless chamber and a second rodless chamber; the rod chamber includes a first rod chamber and a second rod chamber. The first piston is used to divide the inner cavity between the inner wall of the first cylinder body and the outer wall of the second cylinder body into the first rodless chamber and the first rod chamber, and the second piston is used to divide the inner cavity of the second cylinder body into the second rodless chamber and the second rod chamber;

[0067] The first rodless chamber is provided with the oil inlet connected to the closed pump, and the cross-sectional area of the first rodless chamber is equal to the sum of the cross-sectional areas of the first rod chamber and the second rod chamber.

[0068] An oil outlet connected to the closed pump is provided on both the first rod chamber and the second rod chamber.

[0069] In this embodiment, the number of the hydraulic cylinders is two, and the hydraulic cylinders are arranged in parallel on the lower side of the boom. In this embodiment, the first piston rod of the hydraulic cylinder is connected to the boom.

[0070] The construction machinery in this embodiment can be an excavator or a material grabber.

[0071] The construction machinery of this embodiment includes the above-mentioned multi-chamber oil cylinder closed hydraulic system. The boom of the construction machinery is connected to the multi-chamber oil cylinder. The cross-sectional area of the rodless chamber of the multi-chamber oil cylinder closed hydraulic system (referred to as the hydraulic system) connected to the oil inlet is equal to the cross-sectional area of the rod chamber connected to the oil outlet, so as to achieve the same oil inlet and outlet of the hydraulic cylinder body (that is, to achieve a closed hydraulic system). When the hydraulic system is working, the closed pump and the hydraulic cylinder form a closed hydraulic system. The closed hydraulic system can use the closed pump to control the movement direction of the hydraulic oil, and there are no control components such as multi-way valves. Specifically, when the boom moves upward, the hydraulic oil does not pass through the multi-way valve and there is no pressure loss; when the boom moves downward, the flow direction of the hydraulic oil changes (the flow direction of the hydraulic oil is opposite to the flow direction of the hydraulic oil when the piston of the hydraulic cylinder moves upward). At this time, the closed pump is converted into a motor, so that the gravitational potential energy during the fall of the piston of the hydraulic cylinder can be converted into the mechanical energy of the closed pump, realizing the recycling of gravitational potential energy.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A closed hydraulic system for a multi-chamber oil cylinder, characterized in that: It includes a hydraulic cylinder and a closed pump; The hydraulic cylinder is a multi-chamber oil cylinder, and the multi-chamber oil cylinder includes a hydraulic cylinder body, an oil inlet connected to the closed pump, and an oil outlet connected to the closed pump. The hydraulic cylinder body includes a rodless chamber and a rod chamber. The cross-sectional area of the rodless chamber connected to the oil inlet is equal to the cross-sectional area of the rod chamber connected to the oil outlet; The hydraulic cylinder body includes a first cylinder block, a second cylinder block located inside the first cylinder block, and a piston sleeve assembly; The piston sleeve assembly includes a cylindrical first piston rod with an inner cavity, a first piston connected to the first piston rod, a second piston rod connected to the inner cavity of the first piston rod, and a second piston connected to the second piston rod. The first piston rod is nested between the inner wall of the first cylinder block and the outer wall of the second cylinder block, and the second piston rod is arranged inside the second cylinder block; The rodless chamber includes a first rodless chamber and a second rodless chamber; the rod chamber includes a first rod chamber and a second rod chamber. The first piston is used to divide the inner cavity between the inner wall of the first cylinder block and the outer wall of the second cylinder block into the first rodless chamber and the first rod chamber, and the second piston is used to divide the inner cavity of the second cylinder block into the second rodless chamber and the second rod chamber; The oil inlet connected to the closed pump is arranged on any one of the first rodless chamber and the second rodless chamber, and oil outlets connected to the closed pump are opened on both the first rod chamber and the second rod chamber; The cross-sectional area of the rodless chamber provided with the oil inlet is equal to the sum of the cross-sectional areas of the first rod chamber and the second rod chamber; It further includes an accumulator, and an oil port connected to the accumulator is opened on the rodless chamber where the oil inlet is not installed; the accumulator is used to recover the hydraulic oil in the rodless chamber provided with the oil port when the piston sleeve assembly descends, and the accumulator is also used to release hydraulic oil to provide auxiliary power for the piston sleeve assembly when the piston sleeve assembly ascends.

2. The multi-chamber oil cylinder closed hydraulic system according to claim 1, characterized in that: The second cylinder block is coaxially arranged with the first cylinder block, and the cross-section of the first rodless chamber is circular ring-shaped, and the cross-section of the second rodless chamber is circular.

3. The multi-chamber oil cylinder closed hydraulic system according to claim 2, wherein: The first piston rod is a cylindrical piston rod with an internal cavity, and the second piston rod is a cylindrical piston rod.

4. The multi-chamber oil cylinder closed hydraulic system according to claim 1, characterized in that: It further includes a holding valve, and the holding valve is arranged between the closed pump and the rodless chamber provided with the oil inlet.

5. The multi-chamber oil cylinder closed hydraulic system according to any one of claims 1-4, characterized in that: The closed pump is connected to the engine, and the closed pump is used to drive the engine to rotate when the piston sleeve assembly descends.

6. An engineering machinery, characterized in that: It includes the closed hydraulic system for a multi-chamber oil cylinder according to any one of claims 1-5 and a boom, and the boom is connected to the hydraulic cylinder.

7. The construction machinery according to claim 6, characterized in that: The number of the hydraulic cylinders is an even number, and the hydraulic cylinders are arranged in parallel on the lower side of the boom.

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