Hydraulic system, boom system and tunnel construction vehicle

Abstract

The application discloses a hydraulic system, a boom system and a tunnel construction vehicle, and the hydraulic system comprises an oil tank, a power source, a control valve, a follow-up oil cylinder, a lifting oil cylinder, a leveling oil cylinder, a hydraulic control check valve and a hydraulic lock; the control valve comprises a lifting reversing valve and a leveling reversing valve; the oil tank is connected with P ports of the two reversing valves through the power source, and T ports of the two reversing valves are all returned to the oil tank; an A1 port is connected with a rodless cavity of the lifting oil cylinder, a rodless cavity of the follow-up oil cylinder and an X port of the hydraulic control check valve; a B1 port is connected with a rod cavity of the lifting oil cylinder and an A port of the hydraulic control check valve; an A2 port of the leveling reversing valve is connected with a V1 port of the hydraulic lock, a C1 port is connected with a rodless cavity of the leveling oil cylinder and a B port of the hydraulic control check valve, a C2 port is connected with a rod cavity of the leveling oil cylinder and a rod cavity of the follow-up oil cylinder, and a V2 port is connected with a B2 port of the leveling reversing valve. Thus, the output torque demand can be reduced, the boom lightweight design can be realized, energy waste can be reduced, negative pressure formation can be avoided, the service life and operation reliability of the sealing system can be improved, and the operation stability and precision can be improved.

Description

Technical Field

[0001] This application relates to the field of engineering machinery technology, and in particular to a hydraulic system, a boom system, and a tunnel construction vehicle. Background Technology

[0002] In the field of construction machinery, boom leveling is crucial for ensuring operational accuracy and safety. Traditional hydraulic leveling systems typically employ a passive and follow-up structure, where the main boom is rotated by a lifting cylinder, and synchronized movement is achieved through follow-up cylinders connected to the auxiliary boom (such as the work platform). This method relies on preset hinge point relationships between the main boom and the work platform, as well as matching cylinder parameters, to maintain the work platform in a level position throughout the entire lifting angle range.

[0003] However, this traditional design has some significant technical drawbacks: 1. Excessive load and low energy efficiency: Because the main boom lifting cylinder needs to bear additional loads, including the reverse resistance of the follower cylinder, its size and weight are large and increased. This not only limits the lightweight design of the equipment, but also reduces energy transfer efficiency and increases energy consumption.

[0004] 2. Negative pressure hazard: When the follower cylinder is working passively, it is prone to generating negative pressure, which can lead to problems such as damage to seals and increased friction loss, affecting service life and leveling accuracy.

[0005] 3. Response lag and poor stability: The system exhibits response lag due to mechanical backlash and the compressibility of hydraulic oil. Especially during rapid operation or sudden load changes, it may cause the work platform to tilt instantaneously, affecting the stability and accuracy of operation. Summary of the Invention

[0006] The purpose of this application is to provide a hydraulic system, a boom system, and a tunnel construction vehicle to improve the above-mentioned deficiencies.

[0007] The embodiments of this application can be implemented as follows: In a first aspect, the present invention provides a hydraulic system, including an oil tank, a power source, a control valve, a follower cylinder, a lifting cylinder, a leveling cylinder, a hydraulically controlled check valve, and a hydraulic lock; The control valves include a lifting directional valve and a leveling directional valve; The oil tank is connected to the P port of the lifting directional valve and the P port of the leveling directional valve via the power source. The T port of the lifting directional valve and the T port of the leveling directional valve are both connected to the oil tank. The A1 port of the lifting directional valve is connected to the rodless chamber of the lifting cylinder, the rodless chamber of the follower cylinder, and the X port of the hydraulic control check valve. The B1 port of the lifting directional valve is connected to the rod chamber of the lifting cylinder and the A port of the hydraulic control check valve. The A2 port of the leveling directional valve is connected to the V1 port of the hydraulic lock, the C1 port of the hydraulic lock is connected to the rodless chamber of the leveling cylinder and the B port of the hydraulic control check valve, the C2 port of the hydraulic lock is connected to the rod chamber of the leveling cylinder and the rod chamber of the follower cylinder, and the V2 port of the hydraulic lock is connected to the B2 port of the leveling directional valve.

[0008] In an optional embodiment, the hydraulic system further includes a lifting balance valve; The B1 port of the lifting directional valve is connected to the V1 port of the lifting balance valve, the C1 port of the lifting balance valve is connected to the rod chamber of the lifting cylinder, the rodless chamber of the lifting cylinder is connected to the C2 port of the lifting balance valve, and the V2 port of the lifting balance valve is connected to the A1 port of the lifting directional valve.

[0009] In an optional embodiment, the hydraulic system further includes a leveling and balancing valve; The V1 port of the leveling valve is connected to the C1 port of the hydraulic lock, the C1 port of the leveling valve is connected to the rodless chamber of the leveling cylinder, the V2 port of the leveling valve is connected to the C2 port of the hydraulic lock, and the C2 port of the leveling valve is connected to the rod chamber of the leveling cylinder.

[0010] In an optional embodiment, the hydraulic system further includes a relief valve; The rod chamber of the follow-up cylinder, the rod chamber of the leveling cylinder, and the C2 port of the hydraulic lock are all connected to the P port of the relief valve, and the T port of the relief valve is connected to the oil tank.

[0011] In an optional implementation, under the coordinated lifting and leveling condition, the P port of the lifting directional valve is connected to the A1 port, and the B1 port is connected to the T port.

[0012] In an optional implementation, under the coordinated lowering and leveling condition, the P port of the lifting directional valve is connected to the B1 port, and the A1 port is connected to the T port.

[0013] In an optional implementation, under independent leveling and lifting conditions, the P port of the leveling directional valve is connected to the A2 port, the B2 port is connected to the T port, and the A1 port of the lifting directional valve is connected to the T port.

[0014] In an optional implementation, under independent leveling and lowering conditions, the P port of the leveling directional valve is connected to the B2 port, and the A2 port is connected to the T port.

[0015] In a second aspect, the present invention provides a boom system, including a mounting base, a main boom, a working platform, and a hydraulic system as described in any of the foregoing embodiments; One end of the main arm is hinged to the mounting base; The work platform is hinged to the other end of the main arm; Both the lifting cylinder and the follower cylinder have one end hinged to the mounting base, and the other end of both are hinged to the middle of the main boom. One end of the leveling cylinder is hinged to the main arm, and the other end is hinged to the working platform.

[0016] Thirdly, the present invention provides a tunnel construction vehicle, including a frame and the boom system described in the foregoing embodiments, wherein the mounting base is fixed to the frame.

[0017] Compared with the prior art, the beneficial effects of the embodiments of this application include, for example: First, the lifting cylinder no longer bears the weight of the work platform and the leveling reaction force alone. Instead, it is hinged together with the follower cylinder at the mounting base and the middle of the main boom, forming a cooperative force-bearing structure. More importantly, the leveling function is controlled by an independent leveling directional valve and actively driven by the power source through oil supply, rather than relying on the main boom movement to passively drag the follower cylinder to generate hydraulic linkage. As a result, the main boom lifting cylinder only needs to overcome the load of the main boom itself and part of the structure, significantly reducing the required output torque and flow rate, thus allowing for the use of lifting cylinders with smaller cylinder diameters and shorter strokes. This not only reduces the cylinder size and weight, freeing up space at the boom root, reducing structural stress concentration and achieving lightweight design, but also shortens the energy transmission path, reducing energy waste caused by throttling, friction, and valve pressure loss, improving the overall system energy efficiency, and conforming to the development trend of lightweight and energy-saving construction machinery.

[0018] Secondly, the two chambers of the follower cylinder are connected to the main control circuit—its rodless chamber shares the same pressure source (via the lifting directional valve A1 port) with the rodless chamber of the lifting cylinder, while the rod chamber is connected to the rod chamber of the leveling cylinder and controlled to return oil via a hydraulic lock. During the main boom's movement, the follower cylinder is no longer in a completely passive tension / compression state, but is always in a controlled oil replenishment or pressure relief state under the synergistic action of the hydraulic check valve and the hydraulic lock. Especially when the cavity expands, timely oil replenishment can be obtained from the high-pressure side (such as the rodless chamber of the leveling cylinder or the system P port) through the hydraulic check valve, avoiding negative pressure due to insufficient oil filling. This completely avoids problems such as oil film rupture, seal slippage, and air intake caused by negative pressure, significantly extending the service life and leveling accuracy of the cylinder sealing system and moving parts, and improving the reliability of system operation.

[0019] Furthermore, the leveling cylinder's oil inlet and outlet are independently controlled via a leveling directional valve, working in conjunction with a hydraulic lock to achieve position locking and dynamic adjustment. When the boom's posture changes or the workload suddenly shifts, the control system can sense the platform's tilt deviation in real time and precisely control the leveling cylinder's extension and retraction by adjusting the leveling directional valve opening, achieving rapid compensation for the platform's horizontal posture. This active control mechanism eliminates the response lag caused by hydraulic compressibility, pipeline delays, and mechanical clearances in traditional passive systems, significantly improving leveling dynamic accuracy and anti-interference capabilities, resulting in better operational stability and precision.

[0020] Furthermore, since leveling no longer relies on fixed geometric parameter matching, even under conditions such as hydraulic oil aging, component wear, or load changes, online compensation can still be achieved through control strategies, eliminating the need for frequent mechanical adjustments, significantly reducing maintenance costs, and improving the operational adaptability and intelligence level of the equipment throughout its entire life cycle. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the hydraulic system in the coordinated lifting and leveling operation according to an embodiment of this application; Figure 2 This is a schematic diagram of the hydraulic system in the coordinated descent and leveling condition according to an embodiment of this application; Figure 3 This is a schematic diagram of the hydraulic system in the independent leveling and lifting condition according to an embodiment of this application; Figure 4 This is a schematic diagram of the hydraulic system in the independent leveling and lowering condition according to an embodiment of this application.

[0023] Icons: 1-Power source; 2-Control valve; 21-Lifting directional valve; 22-Leveling directional valve; 3-Follow-up cylinder; 4-Lifting cylinder; 5-Leveling cylinder; 6-Lifting balance valve; 7-Leveling balance valve; 8-Hydraulic check valve; 9-Hydraulic lock; 10-Relief valve; 11-Oil tank; 20-Mounting base; 30-Main boom; 40-Working platform. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0027] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0028] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0029] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0030] The following is combined Figures 1 to 4This application provides a detailed description of some embodiments. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0031] This application discloses a boom system, which includes a mounting base 20, a main boom 30, a working platform 40, and a hydraulic system; One end of the main boom 30 is hinged to the mounting base 20; The work platform 40 is hinged to the other end of the main boom 30; The hydraulic system includes an oil tank 11, a power source 1, a control valve 2, a follower cylinder 3, a lifting cylinder 4, a leveling cylinder 5, a hydraulic check valve 8, and a hydraulic lock 9. Among them, one end of both the lifting cylinder 4 and the follower cylinder 3 is hinged to the mounting base 20, and the other end of both is hinged to the middle of the main boom 30. Specifically, the cylinder body of the follower cylinder 3 is connected to the middle hinge point of the main boom 30, and the end of the piston rod is connected to the hinge point of the mounting base 20. As an active power element, it enters oil synchronously with the lifting cylinder 4 to drive the main boom 30 to move. When the boom is lifted, its rod chamber is the core working chamber. One end is connected to the corresponding chamber of the leveling cylinder 5 through a hydraulic pipeline (forming a compression oil supply circuit to drive the leveling cylinder 5), and the other end is connected to the system pressure pipeline (abandoning the original blind chamber design to avoid negative pressure when the volume of the rod chamber changes).

[0032] The cylinder body of the lifting cylinder 4 is connected to the hinge point in the middle of the main boom 30, and the end of the piston rod is connected to the hinge point of the mounting base 20, which is used to provide the driving force for lifting and lowering the main boom 30.

[0033] One end (cylinder body) of the leveling cylinder 5 is hinged to the main boom 30, and the other end (piston rod end) is hinged to the working platform 40. By receiving the oil passively squeezed and transmitted by the rod chamber of the follower cylinder 3, a complete leveling oil supply circuit is formed, which drives its own extension and retraction, thereby driving the working platform 40 to rotate around its own hinge point, realizing horizontal leveling and ensuring the safety of high-altitude operations.

[0034] Control valve 2 includes lifting directional valve 21 and leveling directional valve 22; The oil tank 11 is connected to the P port of the lifting directional valve 21 and the P port of the leveling directional valve 22 via the power source 1. The T port of the lifting directional valve 21 and the T port of the leveling directional valve 22 are both connected to the oil tank 11. Power source 1 can be a hydraulic pump set to provide hydraulic oil with stable pressure and flow for the entire hydraulic system; The lifting directional valve 21 and the leveling directional valve 22 are used to switch the oil circuit so that the power source 1 can actively supply oil to the lifting cylinder 4, the follow-up cylinder 3 and the leveling cylinder 5.

[0035] The A1 port of the lifting directional valve 21 is connected to the rodless chamber of the lifting cylinder 4, the rodless chamber of the follower cylinder 3, and the X port of the hydraulic control check valve 8. The B1 port of the lifting directional valve 21 is connected to the rod chamber of the lifting cylinder 4 and the A port of the hydraulic check valve 8. The A2 port of the leveling and reversing valve 22 is connected to the V1 port of the hydraulic lock 9. The hydraulic lock 9 maintains the function of locking the oil at the output ends of outlets C1 and C2 and maintaining the pressure, thus ensuring the effective transmission of the linkage leveling pressure.

[0036] The C1 port of the hydraulic lock 9 is connected to the rodless chamber of the leveling cylinder 5 and the B port of the hydraulic control check valve 8. The C2 port of the hydraulic lock 9 is connected to the rod chamber of the leveling cylinder 5 and the rod chamber of the follower cylinder 3. The V2 port of the hydraulic lock 9 is connected to the B2 port of the leveling directional valve 22.

[0037] Therefore, firstly, the lifting cylinder 4 no longer bears the weight of the work platform and the leveling reaction force alone, but is hinged together with the follower cylinder 3 at the middle of the mounting base 20 and the main boom 30, forming a cooperative force-bearing structure. More importantly, the leveling function is controlled by an independent leveling directional valve 22, and the leveling cylinder 5 is actively driven by the power source 1 through oil supply, rather than relying on the main boom 30 to passively drag the follower cylinder 3 to generate hydraulic linkage. As a result, the lifting cylinder 4 of the main boom 30 only needs to overcome the load of the main boom 30 itself and part of the structural load, significantly reducing the required output torque and flow rate, thus allowing the use of a smaller cylinder diameter and shorter stroke lifting cylinder 4. This not only reduces the cylinder volume and weight, frees up space at the boom root, reduces structural stress concentration, and achieves lightweight design, but also shortens the energy transmission path, reduces energy waste caused by throttling, friction, and valve pressure loss, and improves the overall system energy efficiency, which is in line with the development trend of lightweight and energy-saving construction machinery.

[0038] Secondly, the two chambers of the follower cylinder 3 are connected to the main control circuit respectively—its rodless chamber shares the same pressure source (via port A1 of the lifting directional valve) with the rodless chamber of the lifting cylinder 4, while its rod chamber is connected to the rod chamber of the leveling cylinder 5 and controlled to return oil via the hydraulic lock 9. During the movement of the main boom 30, the follower cylinder 3 is no longer in a completely passive tension / compression state, but is always in a controlled oil replenishment or pressure relief state under the synergistic action of the hydraulic check valve 8 and the hydraulic lock 9. Especially when the cavity expands, timely oil replenishment can be obtained from the high-pressure side (such as the rodless chamber of the leveling cylinder 5 or the system P port) through the hydraulic check valve 8, avoiding the formation of negative pressure due to the inability of oil to fill in time. This completely avoids problems such as oil film rupture, seal overturning, and air intake caused by negative pressure, significantly extending the service life and leveling accuracy of the cylinder sealing system and moving parts, and improving the reliability of system operation.

[0039] Furthermore, the leveling cylinder 5 is independently controlled via the leveling directional valve 22, which, in conjunction with the hydraulic lock 9, enables position locking and dynamic adjustment. When the boom 30 changes posture or the workload changes abruptly, the control system can detect the tilt deviation of the work platform 40 in real time and precisely control the extension and retraction of the leveling cylinder 5 by adjusting the opening of the leveling directional valve 22, thus achieving rapid compensation of the horizontal posture of the work platform 40. This active control mechanism eliminates the response lag caused by hydraulic compressibility, pipeline delay, and mechanical clearance in traditional passive systems, significantly improving the dynamic accuracy and anti-interference capability of leveling, resulting in better operational stability and precision.

[0040] Furthermore, since leveling no longer relies on fixed geometric parameter matching, even under conditions such as hydraulic oil aging, component wear, or load changes, online compensation can still be achieved through control strategies, eliminating the need for frequent mechanical adjustments, significantly reducing maintenance costs, and improving the operational adaptability and intelligence level of the equipment throughout its entire life cycle.

[0041] In this embodiment, the hydraulic system also includes a lifting balance valve 6; The B1 port of the lifting directional valve 21 is connected to the V1 port of the lifting balance valve 6, the C1 port of the lifting balance valve 6 is connected to the rod chamber of the lifting cylinder 4, the rodless chamber of the lifting cylinder 4 is connected to the C2 port of the lifting balance valve 6, and the V2 port of the lifting balance valve 6 is connected to the A1 port of the lifting directional valve 21. Thus, the lifting balance valve 6 provides load holding and negative load hydraulic throttling functions for the lifting cylinder 4.

[0042] The hydraulic system also includes a leveling valve 7; the V1 port of the leveling valve 7 is connected to the C1 port of the hydraulic lock 9, the C1 port of the leveling valve 7 is connected to the rodless chamber of the leveling cylinder 5, the V2 port of the leveling valve 7 is connected to the C2 port of the hydraulic lock 9, and the C2 port of the leveling valve 7 is connected to the rod chamber of the leveling cylinder 5. Thus, the leveling valve 7 provides load holding and negative load hydraulic throttling functions for the leveling cylinder 5.

[0043] When the boom system reaches a specific position (e.g., the work platform 40 has been leveled to its horizontal limit and the piston of the leveling cylinder 5 has reached the end of its stroke), if the main boom 30 continues to lift or lower, the leveling cylinder 5 will be unable to extend or retract further. At this time, the follower cylinder 3 is still passively moved by the main boom 30, and its rod chamber is connected to the rod chamber of the leveling cylinder 5 through a hydraulic circuit, forming a closed or semi-closed "passive compression chamber".

[0044] As the main boom 30 continues to move, the volume of the cavity is forcibly compressed. The incompressibility of the oil will cause the pressure inside the cavity to rise sharply, which is very likely to exceed the pressure limit of the components, causing seal failure, cylinder deformation or even pipe burst.

[0045] Therefore, in this embodiment, the hydraulic system also includes a relief valve 10; The rod chamber of the follower cylinder 3, the rod chamber of the leveling cylinder 5 (via the leveling balance valve 7), and the C2 port of the hydraulic lock 9 are all connected to the P port of the relief valve 10, and the T port of the relief valve 10 is connected to the oil tank 11.

[0046] In this way, when the pipeline pressure reaches the preset safety value (slightly higher than the normal working pressure but lower than the system failure pressure), the leakage channel is automatically opened to actively release excess oil, effectively avoiding hydraulic overload caused by excessive mechanical stroke, and realizing "soft limit" protection for the leveling and follow-up circuit.

[0047] The working process of the hydraulic system in this embodiment under different working conditions is described below: 1. Under the condition of coordinated lifting and leveling: refer to Figure 1 The lifting directional valve 21 has its P port connected to its A1 port and its B1 port connected to its T port. That is, when the valve core of the lifting directional valve 21 is in the lower working position, the hydraulic power source 1 is started, and the pressure oil source is transmitted through the B port of the power source 1 to the overall oil inlet P of the control valve 2. The oil outlet circuit of the oil port A1 is connected to the high-pressure oil, which is connected to: the rodless chamber of the follower cylinder 3, the rodless chamber of the lifting cylinder 4 through the V2 port and C2 port of the lifting balance valve 6, and the control port X of the hydraulic control check valve 8.

[0048] After the rodless chamber of the lifting cylinder 4 and the rodless chamber of the follower cylinder 3 simultaneously deliver high-pressure oil, under the rigid adjustment of the main boom 30's mechanical structure, the piston rods of the follower cylinder 3 and the lifting cylinder 4 extend synchronously, driving the main boom 30 to rotate around the hinge point of the mounting base 20, thereby achieving the lifting of the main boom 30; at this time, the follower cylinder 3, as the active power element, will change its rod chamber volume accordingly as its piston rod extends (cooperating with the lifting cylinder 4) (the rod chamber volume shrinks), and the oil in the blind chamber is passively squeezed, and the oil is transmitted to: the hydraulic lock 9 outlet C2, the overflow valve 10 inlet P, and the leveling balance valve 7 via port V2 and port C2 to the leveling cylinder 5 rod chamber; at this time, the hydraulic... Lock 9 and overflow valve 10 (not reaching the preset pressure) are both in the locked state. Therefore, the passively squeezed oil enters the rod chamber of the leveling cylinder 5 through the leveling balance valve 7. At the same time, the piston displacement of the leveling cylinder 5 is adjusted. The piston rod retracts and drives the working platform 40 to rotate around the hinge point of the mounting seat 20, thereby lowering the working platform 40. The oil in the rodless chamber of the leveling cylinder 5 flows through port C1 and V1 of the leveling balance valve 7 to port B of the hydraulic control check valve 8 and port C1 of the hydraulic lock 9. At this time, after the pressure is applied to port X of the hydraulic control check valve 8, port B to port A are connected. The oil in the rodless chamber of the leveling cylinder 5 merges with the return oil from the rod chamber of the lifting cylinder 4 after passing through the hydraulic control check valve 8 and flows back to port B1 and port T of the lifting reversing valve 21 to the oil tank 11.

[0049] At this time, the rod chamber of the follower cylinder 3 serves as the active extrusion chamber, while the rodless chamber at the other end is always connected to the oil inlet (i.e., power source 1); the rod chamber of the leveling cylinder 5 serves as the passive extrusion chamber, while the rodless chamber at the other end is always connected to the return oil (i.e., oil tank 11); the two chambers inside the cylinder will always maintain a stable positive pressure, abandoning the original design where both chambers are blind chambers, and the hydraulic oil continuously provides lubrication for the seals and friction pairs, completely avoiding the problems of negative pressure suction and lack of lubrication caused by the original blind chamber design.

[0050] Meanwhile, because the rodless chamber of the follower cylinder 3 is connected to the pressure oil source, the increase in the total pressure application area in the same boom structure enhances the overall driving capability of the boom. The internal driving load of the leveling cylinder 5, which is a secondary transmission, is completely transferred to the follower cylinder 3 to provide driving force. The lifting cylinder 4 is no longer the only power element. When the follower cylinder 3 is connected to the system pressure, it provides the reverse resistance generated by the passive movement of the auxiliary boom, and also shares the load of the main boom 30 with the lifting cylinder 4. This greatly reduces the stress and load redundancy of the lifting cylinder 4 and the boom root structure, which facilitates the subsequent lightweight design of the boom structure.

[0051] 2. Under the condition of coordinated descent and leveling: refer to Figure 2The lifting directional valve 21 has its P port connected to its B1 port and its A1 port connected to its T port. When the hydraulic power source 1 is started, the pressure oil source is transmitted through the B port of the power source 1 to the oil inlet P of the control valve 2. The oil outlet circuit of the lifting directional valve 21's B1 port is connected to high-pressure oil, which is connected to: the lifting cylinder 4's rod chamber via the V1 and C1 ports of the lifting balance valve 6; the hydraulic lock 9's C1 port via the A and B ports of the hydraulic control check valve 8 (the hydraulic control check valve 8's oil ports A and B are normally open); and the leveling balance valve 7's V1 port (and then via the C1 port to the leveling cylinder 5's rodless chamber). At this time, the C1 port of the hydraulic lock 9 is in the locked state. Therefore, the rod chamber of the lifting cylinder 4 and the rodless chamber of the leveling cylinder 5 simultaneously deliver high-pressure oil. As the active power element, the leveling cylinder 5, as its piston rod extends, drives the working platform 40 to rotate around the hinge point of the mounting seat 20 to lift the working platform 40. The volume of its rod chamber will change accordingly as the piston rod extends (the volume of the rod chamber shrinks). The oil in the blind chamber is passively squeezed and transmitted to: port C2 of the hydraulic lock 9; port P of the overflow valve 10; and through port V2 and C2 of the leveling balance valve 7 to the rod chamber of the follower cylinder 3. At this time, the hydraulic lock 9 and the overflow valve 10 (not reaching the preset pressure) are both locked. Therefore, the passively squeezed oil enters the rod chamber of the follower cylinder 3 to drive the piston rod to retract. At this time, under the rigid adjustment of the main boom mechanical structure, the piston rods of the follower cylinder 3 and the lifting cylinder 4 will retract synchronously, driving the main boom to rotate around the hinge point of the mounting seat 20, thereby realizing the descent of the main boom. At the same time, the piston displacement of the leveling cylinder 5 is limited, which plays a stroke limiting role. The oil in the rodless chamber of the lifting cylinder 4 flows through the C2 port and V2 port of the lifting balance valve 6 and merges with the return oil in the rodless chamber of the follower cylinder 3 to the A1 port and T port of the lifting reversing valve 21, and finally returns to the oil tank 11.

[0052] At this time, the rod chamber of the follower cylinder 3 serves as the passive extrusion chamber, while the rodless chamber at the other end is always connected to the return oil; the rod chamber of the leveling cylinder 5 serves as the active extrusion chamber, while the rodless chamber at the other end is always connected to the inlet oil; the two chambers inside the cylinder will always maintain a stable positive pressure, abandoning the traditional design where both chambers of the follower cylinder are blind chambers, and the hydraulic oil continuously provides lubrication for the seals and friction pairs, completely avoiding the negative pressure suction and lack of lubrication problems caused by the original blind chamber design. The rodless chamber of the leveling cylinder 5 is connected to the pressure oil source, which also increases the total area of ​​pressure action in the boom structure, thereby improving the overall driving capability of the boom. The internal driving load of the leveling cylinder 5, which is no longer a secondary transmission, is completely provided by itself. The lifting cylinder 4 is no longer the only power element. Since the leveling cylinder 5 is connected to the system pressure, it not only provides the lifting force generated by the movement of the work platform 40, but also transmits the pressure oil in the rod chamber to the follower cylinder 3 to share the reverse running resistance of the main boom. This also reduces the force on the lifting cylinder 4 during the descent of the main boom 30.

[0053] Meanwhile, the lifting cylinder 4 and its connected hinge point and the working platform 40 are completely free structures. Therefore, during the coordinated descent and leveling process, its rodless chamber is connected to pressure oil for compensation, so that the passive compression pipeline is kept full by the pressure oil. In each action cycle, the lag phenomenon during boom movement is eliminated and the leveling response is improved.

[0054] 3. Under independent leveling and lifting conditions: refer to Figure 3 The P port of the directional adjustment valve 22 is connected to the A2 port, and the B2 port is connected to the T port. When the hydraulic power source 1 is started, the pressure oil source is transmitted through its B port to the oil inlet P of the control valve 2. The oil outlet circuit of the A2 port of the directional adjustment valve 22 is connected to the high-pressure oil, which is transmitted through the V1 port and C1 port of the hydraulic lock 9 to the B port of the hydraulic control check valve 8 and through the V1 port and C1 port of the balancing valve 7 to the rodless chamber of the balancing cylinder 5. Meanwhile, the A1 port and T port of the lifting directional valve 21 are connected. Therefore, the X port of the hydraulic control check valve 8 is connected to the return oil through the A1 port and T port of the lifting directional valve 21. Thus, the B port of the hydraulic control check valve 8 is locked. The pressurized oil will enter the rodless chamber of the leveling cylinder 5 to drive the piston rod to extend, thereby rotating the working platform 40 around the hinge point of the mounting seat 20 to lift the working platform 40. The volume of its rod chamber is reduced, and the oil in the rod chamber flows through the C2 port and V2 port of the leveling balance valve 7 to the C2 port of the hydraulic lock 9. At this time, when the V1 of the hydraulic lock 9 is under pressure, the passage from its C2 port to its V2 port is opened. Therefore, the oil in the rod chamber of the leveling cylinder 5 can return to the oil tank 11 through the C2 port and V2 port of the hydraulic lock 9 via the B2 and T ports of the leveling directional valve 22.

[0055] 4. Under independent leveling and descent conditions: refer to Figure 4 The P port of the directional adjustment valve 22 is connected to the B2 port, and the A2 port is connected to the T port. When the hydraulic power source 1 is started, the pressure oil source is transmitted to the oil inlet P of the control valve 2 through its B port. The oil outlet circuit of the directional adjustment valve 22 is connected to the high pressure oil, and then flows through the V2 port and C2 port of the hydraulic lock 9 to: the rod chamber of the directional adjustment cylinder 5, the P port of the relief valve 10, and the rod chamber of the directional adjustment cylinder 5 through the V2 port and C2 port of the directional adjustment valve 7. At this time, the overflow valve 10 (not reaching the preset pressure) is locked. The rod chamber of the follower cylinder 3 is connected to generate tension, which is transmitted to the rodless chamber of the lifting cylinder 4 under the rigid constraint of the main boom 30 mechanical structure, causing the pressure to rise. Due to the hinge point and the ratio of the working area, the pressure rise in the rodless chamber of the lifting cylinder 4 is insufficient to passively open the set pressure of the lifting balance valve 6. Therefore, the lifting balance valve 6 is locked, providing a reverse limiting force to the follower cylinder 3, so that the rod chamber of the follower cylinder 3 is also locked, and pressurized oil enters. The piston rod of the leveling cylinder 5 retracts through the rod chamber, causing the working platform 40 to rotate around the hinge point of the mounting base 20, thus lowering the working platform 40. The volume of its rodless chamber decreases, and the oil in the rodless chamber flows through the C1 and V1 ports of the leveling balance valve 7 to the C1 port of the hydraulic lock 9. At this time, when the V2 port of the hydraulic lock 9 is under pressure, the channel from the C1 port to the V1 port is opened, and the oil in the rodless chamber of the leveling cylinder 5 can return to the oil tank 11 through the C1 and V1 ports of the hydraulic lock 9, and the A2 and T ports of the leveling directional valve 22 in sequence.

[0056] This embodiment also discloses a tunnel construction vehicle, which includes a frame and the above-mentioned boom system, wherein the mounting base 20 is fixed to the frame.

[0057] In summary, this embodiment discloses a hydraulic system, a boom system, and a tunnel construction vehicle, which have at least the following advantages compared to the prior art: 1. Optimize power distribution and reduce the size of lifting cylinder 4: The follower cylinder 3 and the main boom lifting cylinder 4 are synchronously and actively supplied with oil, working together to bear the driving force of the main boom and the work platform 40 related loads. This completely changes the existing technology where the follower cylinder 3 is passively subjected to force and the main boom lifting cylinder 4 bears the load alone, significantly reducing the load on a single cylinder. As a result, the cylinder diameter, rod diameter, and weight of the main boom lifting cylinder 4 can be significantly reduced, achieving a lightweight design for the overall boom and platform. At the same time, it reduces the stress load on the main boom root hinge point and improves the reliability of the boom structure.

[0058] 2. Optimized piping to prevent air suction, improving system stability and operational safety: The original design of the follower cylinder 3, where both chambers were blind cavities, was abandoned. Instead, the follower rod chamber was changed to "one path connects to the leveling cylinder 5, and the other path connects to the return oil." This retains the core logic of the pipeline compression transmission of oil to drive the leveling cylinder 5, while completely solving the problems of insufficient air intake, air intake, and oil replenishment under the current passive working conditions, avoiding phenomena such as cavitation and crawling vibration. At the same time, the follower cylinder 3 always maintains a stable positive pressure, and the hydraulic oil continuously lubricates the seals and friction pairs. The seals are subjected to reasonable stress and are not prone to bending and wear. The service life of the cylinder and seals is extended, the risk of system leakage is significantly reduced, and the instantaneous tilting of the work platform is effectively avoided, ensuring the safety of high-altitude operations.

[0059] 3. Leveling response is rapid and more accurate: The dual-cylinder active collaborative drive of the main boom has a short energy transmission path and no mechanical transmission lag; the follow-up rod chamber directly squeezes and transmits oil to the leveling cylinder 5 through the pipeline, and the oil flow is smooth and without delay. Compared with the existing passive follow-up system, the leveling response speed is greatly improved, so that the lifting of the main boom 30 and the leveling action of the working platform 40 are precisely synchronized, improving the operation accuracy and stability.

[0060] 4. Highly adaptable and with low maintenance costs: The oil supply flow and pressure of the two cylinders can be actively adjusted by the two sets of control valves to adapt to different working loads and working conditions, and to various aerial work platforms. The parameter matching design is flexible and can adjust the hinge point position and cylinder parameters according to the structure of the main boom 30 of different models, which is highly versatile. The probability of system failure is reduced (no common problems such as air suction and seal wear), and there is no need for frequent inspection, oiling and parameter calibration, which significantly reduces maintenance costs.

[0061] 5. High structural compatibility and easy to promote: The core improvement is in the hydraulic circuit and pipeline design. The overall installation structure of the original main boom, working platform 40 and leveling cylinder 5 has not been changed. There is no need to make major modifications to the aerial work platform 40. The modification is simple and low-cost, and it is easy to promote and apply to existing equipment. At the same time, the core logic of pipeline extrusion-driven leveling is retained, which is in line with the operating habits of existing equipment and does not require adjustment of the operator's operation method.

[0062] 6. Energy-efficient and highly effective: The active oil supply circuit avoids friction loss and energy loss under passive follow-up conditions, and the energy utilization rate of the dual-cylinder collaborative drive is improved compared with the single-cylinder passive system. At the same time, the design of the follow-up rod chamber to return oil reduces oil flow resistance, reduces energy loss, further reduces the energy consumption of the aerial work platform, and improves the economic efficiency of operation.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A hydraulic system characterized by, It includes an oil tank (11), a power source (1), a control valve (2), a follow-up cylinder (3), a lifting cylinder (4), a leveling cylinder (5), a hydraulic check valve (8), and a hydraulic lock (9). The control valve (2) includes a lifting directional valve (21) and a leveling directional valve (22). The oil tank (11) is connected to the P port of the lifting reversing valve (21) and the P port of the leveling reversing valve (22) through the power source (1). The T port of the lifting reversing valve (21) and the T port of the leveling reversing valve (22) are both connected to the oil tank (11). The A1 port of the lifting directional valve (21) is connected to the rodless chamber of the lifting cylinder (4), the rodless chamber of the follower cylinder (3), and the X port of the hydraulic control check valve (8). The B1 port of the lifting directional valve (21) is connected to the rod chamber of the lifting cylinder (4) and the A port of the hydraulic check valve (8). The A2 port of the leveling directional valve (22) is connected to the V1 port of the hydraulic lock (9), the C1 port of the hydraulic lock (9) is connected to the rodless chamber of the leveling cylinder (5) and the B port of the hydraulic control check valve (8), the C2 port of the hydraulic lock (9) is connected to the rod chamber of the leveling cylinder (5) and the rod chamber of the follower cylinder (3), and the V2 port of the hydraulic lock (9) is connected to the B2 port of the leveling directional valve (22).

2. The hydraulic system of claim 1, wherein, The hydraulic system also includes a lifting balance valve (6). The B1 port of the lifting directional valve (21) is connected to the V1 port of the lifting balance valve (6), the C1 port of the lifting balance valve (6) is connected to the rod chamber of the lifting cylinder (4), the rodless chamber of the lifting cylinder (4) is connected to the C2 port of the lifting balance valve (6), and the V2 port of the lifting balance valve (6) is connected to the A1 port of the lifting directional valve (21).

3. The hydraulic system of claim 1, wherein, The hydraulic system also includes a leveling and balancing valve (7). The V1 port of the leveling valve (7) is connected to the C1 port of the hydraulic lock (9), the C1 port of the leveling valve (7) is connected to the rodless chamber of the leveling cylinder (5), the V2 port of the leveling valve (7) is connected to the C2 port of the hydraulic lock (9), and the C2 port of the leveling valve (7) is connected to the rod chamber of the leveling cylinder (5).

4. The hydraulic system of claim 1, wherein, The hydraulic system also includes a relief valve (10). The rod chamber of the follower cylinder (3), the rod chamber of the leveling cylinder (5), and the C2 port of the hydraulic lock (9) are all connected to the P port of the overflow valve (10), and the T port of the overflow valve (10) is connected to the oil tank (11).

5. The hydraulic system according to any one of claims 1-4, characterized in that, In the coordinated lifting and leveling operation, the lifting directional valve (21) has its P port connected to its A1 port and its B1 port connected to its T port.

6. The hydraulic system according to any one of claims 1-4, characterized in that, In the coordinated lowering and leveling operation, the P port of the lifting directional valve (21) is connected to the B1 port, and the A1 port is connected to the T port.

7. The hydraulic system according to any one of claims 1-4, characterized in that, In the independent leveling and lifting operation, the P port of the leveling directional valve (22) is connected to the A2 port, the B2 port is connected to the T port, and the A1 port of the lifting directional valve (21) is connected to the T port.

8. The hydraulic system of any one of claims 1-4, wherein, In the independent leveling descending working condition, the P port and the B2 port of the leveling reversing valve (22) are connected, and the A2 port and the T port are connected.

9. An arm system, characterized by The hydraulic system comprises a mounting base (20), a main arm (30), a working platform (40), and the hydraulic system according to any one of claims 1-8. One end of the main arm (30) is hinged to the mounting base (20). The working platform (40) is hinged to the other end of the main arm (30). One end of the lifting oil cylinder (4) and one end of the follow-up oil cylinder (3) are both hinged to the mounting base (20), and the other ends of the two are both hinged to the middle part of the main arm (30). One end of the leveling oil cylinder (5) is hinged to the main arm (30), and the other end is hinged to the working platform (40).

10. A tunneling operation vehicle characterized by comprising: The arm support system comprises a vehicle frame and the arm support system according to claim 9, wherein the mounting base (20) is fixed to the vehicle frame.

Images