Constant flow control valve group, auxiliary arm control module, whole machine hydraulic system and crane

Abstract

This application discloses a constant flow control valve assembly, a boom control module, a complete hydraulic system, and a crane. The constant flow control valve assembly includes a cartridge valve; a cartridge directional valve, including a working port on one side and a main return port and a directional valve inlet port selectively connected to the working port on the other side, the working port being connected to the control port of the cartridge valve, and the directional valve inlet port being connected to the main inlet port of the cartridge valve; and a feedback switching valve, disposed in a working feedback oil circuit connecting the main inlet port of the cartridge valve and the main feedback port of the constant flow control valve assembly. The boom control module includes the constant flow control valve assembly and the main directional valve. The complete hydraulic system includes the boom control module and the boom luffing cylinder, and may also include a load-sensitive oil pump and a main valve. This application allows the boom hydraulic system to be directly integrated into the existing complete hydraulic system as a sub-module without requiring modifications to the original system.

Description

Technical Field

[0001] This application belongs to the field of hydraulic technology for construction machinery, specifically relating to a constant flow control valve group, a secondary boom control module, a complete hydraulic system, and a crane. Background Technology

[0002] Crane jib is mainly used to increase the lifting height and expand the working range of a crane. During operation, the working radius of the jib needs to be changed frequently to adapt to different working conditions. There are two ways to change the luffing radius of a jib: mechanical luffing plate luffing and hydraulic cylinder luffing. The mechanical luffing plate method not only has more components and a more complex mechanism, but more importantly, the luffing action is not flexible and the reliability is poor. Directly controlling the luffing radius of the jib with a hydraulic cylinder is simple, efficient and flexible, and it is also easy to realize automation and intelligence, so its application is becoming more and more widespread.

[0003] When using a hydraulic cylinder luffing system, the boom's raising and lowering are controlled by the extension and retraction of the piston rod in the boom luffing cylinder. Generally, the boom luffing system is supplied with oil by a separately designed fixed-displacement pump, which supplies oil to the cylinder via a hose reel. The main directional valve controls the extension and retraction of the cylinder piston rod. Locking of the luffing cylinder is typically achieved by a two-way hydraulic lock. The main directional valve and fixed-displacement pump are unloaded when the luffing cylinder is not in motion. This conventional boom luffing system requires an independent oil pump. Furthermore, due to the high pressure requirements, an additional plunger pump is necessary, requiring an additional power take-off port or a pump jacking interface. The plunger pump's large size occupies considerable space, potentially affecting the overall layout of the machine. Additionally, the system has poor responsiveness; after the luffing command is issued, the hydraulic oil travels from the oil source through dozens of turns of hose to reach the cylinder before pressure is built up and the action is executed, resulting in a long system response time. Summary of the Invention

[0004] The purpose of this application is to provide a constant flow control valve group, a boom control module, a complete hydraulic system, and a crane, so as to simplify the boom hydraulic system and enable its quick integration with the complete hydraulic system.

[0005] To achieve the above objectives, the first aspect of this application provides a constant flow control valve assembly, applied in the jib control module of a crane, comprising:

[0006] A cartridge valve, the main outlet of which is hydraulically connected to the inlet of the main directional valve of the auxiliary boom control module;

[0007] A cartridge directional valve includes a working port on one side and a main return port and a directional valve inlet port on the other side, which are selectively connected to the working port. The working port is connected to the control port of the cartridge valve, and the directional valve inlet port is connected to the main inlet port of the cartridge valve.

[0008] A feedback switching valve is used to control the pressure feedback from the main inlet to the oil pump. The feedback switching valve is installed in the working feedback oil circuit connecting the main inlet of the cartridge valve and the main feedback oil port of the constant flow control valve group.

[0009] In some embodiments, the main feedback port, the main inlet port, and the main return port of the constant flow control valve assembly are each connected to a pump quick-connect fitting for connecting to the hydraulic pump circuit.

[0010] In some embodiments, an oil inlet bypass oil passage is connected between the oil inlet of the directional valve and the main oil inlet of the cartridge valve. The oil inlet bypass oil passage is provided with a first check valve, which is configured to allow hydraulic oil to flow from the main oil inlet to the oil inlet of the directional valve and to cut off the flow in the reverse direction.

[0011] In some embodiments, the main feedback port is connected to a pressure sensor and an electro-proportional relief valve; and / or, the working feedback oil circuit is further provided with a feedback damper connected in series with the feedback switching valve; and / or, both the cartridge directional valve and the feedback switching valve are electromagnetic directional valves.

[0012] In some embodiments, a supplementary connection oil circuit is connected between the oil inlet of the reversing valve and the main oil outlet of the cartridge valve. The supplementary connection oil circuit is provided with a second check valve, which is configured to allow hydraulic oil to flow from the oil outlet of the cartridge valve to the oil inlet of the reversing valve and to cut off the flow in the reverse direction.

[0013] A second aspect of this application provides a secondary arm control module, comprising:

[0014] The aforementioned constant flow control valve assembly; and

[0015] The main directional valve has an inlet port on one side connected to the main outlet port of the cartridge valve, and a return port on one side connected to the main return port of the constant flow control valve group. The working port on the other side of the main directional valve is used to connect to the control arm luffing cylinder.

[0016] In some embodiments, the auxiliary arm control module includes:

[0017] An accumulator is hydraulically connected to the oil inlet of the main directional valve;

[0018] An energy storage switch valve is used to control the oil circuit connection between the energy storage device and the oil inlet of the main directional valve.

[0019] In some embodiments, the working port of the main directional valve includes a first working port for hydraulically connecting the rodless chamber of the auxiliary boom luffing cylinder and a second working port for hydraulically connecting the rod chamber of the auxiliary boom luffing cylinder, the second working port being connected to an overflow valve.

[0020] In some embodiments, a first hose reel is provided in the connecting pipe between the oil inlet and the oil return port on one side of the main directional valve, and a second hose reel is provided in the connecting pipe between the working oil port on the other side. The outer end of the second hose reel is provided with a quick-connect coupling for connecting the oil circuit of the oil cylinder.

[0021] A third aspect of this application provides a complete machine hydraulic system, including:

[0022] The aforementioned auxiliary boom control module; and

[0023] The auxiliary boom luffing cylinder is connected to the working oil port of the main directional valve.

[0024] In some embodiments, the auxiliary boom luffing cylinder includes a balance valve disposed in the rodless chamber working oil circuit and used for locking the rodless chamber oil. The balance valve includes a balance valve core, the control port of which is connected to the rod chamber working oil circuit through a pilot oil circuit with inlet damping and to the low-pressure side of the rodless chamber working oil circuit through a bypass oil circuit with bypass damping.

[0025] In some embodiments, the overall hydraulic system further includes:

[0026] A load-sensitive oil pump and a main valve, wherein the load-sensitive oil pump is used to pump hydraulic oil toward the main inlet of the main valve and the constant flow control valve group, respectively;

[0027] A shuttle valve, wherein the first comparison port of the shuttle valve is connected to the feedback port of the main valve, and the second comparison port is connected to the main feedback port of the constant flow control valve group, and the outlet port of the shuttle valve is connected to the pump feedback port of the load-sensitive oil pump.

[0028] A fourth aspect of this application provides a crane, the crane including a complete hydraulic system according to this application.

[0029] Through the design of the constant flow control valve group and the auxiliary boom control module of this application, the auxiliary boom hydraulic system can be directly connected to the existing whole machine hydraulic system as a sub-module without modifying the original system. Specifically, through the combined design of cartridge valves, cartridge directional valves, and feedback switching valves, after connection to the whole machine hydraulic system, the main pump provides a constant flow oil source to the auxiliary boom subsystem, eliminating the need for additional oil pumps, oil source management, and other related components and equipment. Furthermore, the cartridge valves have a large flow capacity, ensuring the flow requirements of the auxiliary boom luffing cylinder.

[0030] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0031] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without any inventive effort. In the drawings:

[0032] Figure 1 A hydraulic schematic diagram of a constant flow control valve assembly according to a specific embodiment of this application;

[0033] Figure 2 The hydraulic schematic diagram is shown for a specific embodiment of the boom control module according to this application.

[0034] Figure 3 This is a hydraulic schematic diagram of the overall hydraulic system according to a specific embodiment of this application;

[0035] Figure 4 for Figure 3 The hydraulic schematic diagram of the pump section shows the main connecting oil circuits of the load-sensitive pump.

[0036] Figure 5 The diagram shows Figure 3 The hydraulic oil flow direction of the entire machine's hydraulic system when the boom is not in use or the boom hook is not lifting loads;

[0037] Figure 6 The diagram shows Figure 3 The direction of hydraulic oil flow in the overall hydraulic system of the machine during the boom luffing preparation state;

[0038] Figure 7 The diagram illustrates the flow of hydraulic oil during accumulator filling;

[0039] Figure 8 The diagram shows Figure 3 The direction of hydraulic oil flow in the overall hydraulic system when the boom cylinder extends;

[0040] Figure 9 The diagram shows Figure 3 The hydraulic oil flow direction of the entire machine's hydraulic system when the boom luffing action stops and when lifting heavy objects; and

[0041] Figure 10 The diagram shows Figure 3 The direction of hydraulic oil flow in the overall hydraulic system of the machine when the boom is in the lowered position.

[0042] Explanation of reference numerals in the attached figures

[0043] Detailed Implementation

[0044] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0045] The constant flow control valve assembly, the auxiliary boom control module, the overall hydraulic system, and the crane according to this application are described below with reference to the accompanying drawings.

[0046] This application first discloses a novel constant flow control valve assembly, namely a cartridge valve assembly, for providing a constant flow oil source to the subsystem driving the boom luffing cylinder 1. It is convenient to connect to the main pump or main oil supply circuit of the whole machine hydraulic system. Compared with the existing boom luffing cylinder system, there is no need to add oil pumps, oil source management and other related components and equipment.

[0047] like Figure 1 As shown, in one specific embodiment, the constant flow control valve assembly includes:

[0048] Cartridge valve 12;

[0049] The cartridge directional valve 15 includes a working port on one side and a main return port T0 and a directional valve inlet port P0 on the other side, which are selectively connected to the working port. The working port is connected to the control port of the cartridge valve 12, and the directional valve inlet port P0 is connected to the main inlet port P of the cartridge valve 12.

[0050] Feedback switching valve 11 is installed in the working feedback oil circuit connecting the main oil inlet P of cartridge valve 12 and the main feedback oil inlet K of constant flow control valve group.

[0051] Combination Figure 3 As can be seen, the load-sensitive oil pump 17 of the entire hydraulic system can not only drive the main boom through the main valve 18, but also distribute oil to the main inlet P of the constant flow control valve to drive the auxiliary boom luffing cylinder. Therefore, the auxiliary boom luffing cylinder does not require a dedicated drive oil pump and corresponding oil source management components. Specifically, pressurized oil enters the side port of the cartridge valve 12 through the main inlet P. When the control port is open, the pressurized oil in the side port can flow out through the main outlet A of the cartridge valve 12, flowing to the reversing valve of the auxiliary boom luffing cylinder 1. Figure 3 The main directional valve 7 in the middle.

[0052] Furthermore, an oil bypass circuit is connected between the directional valve inlet P0 and the main inlet P of the cartridge valve 12. This bypass circuit includes a first check valve 14, which allows hydraulic oil to flow from the main inlet P to the directional valve inlet P0 and is deactivated in the reverse direction. Thus, a portion of the pressurized oil can bypass the main inlet P and enter the cartridge directional valve 15, thereby entering the control port of the cartridge valve 12 to drive it open. Further, a supplementary connection circuit can be connected between the directional valve inlet P0 and the main outlet A of the cartridge valve 12. This supplementary connection circuit includes a second check valve 14', which allows hydraulic oil to flow from the outlet of the cartridge valve 12 to the directional valve inlet P0 and is deactivated in the reverse direction. In this way, it can be ensured that the pressure at the inlet P0 of the directional valve is the greater of the pressure at the main inlet P or the main outlet A of the cartridge valve 12, so that the cartridge valve 12 can be reliably closed under the specific control conditions of the cartridge directional valve 15.

[0053] The constant flow control valve assembly has a main feedback port K, which is used to feed back the pressure from the main inlet P of the cartridge valve 12 to the oil pump, thereby adjusting the pump's displacement, etc. The presence or absence of oil pressure feedback can be controlled by the feedback switch valve 11. To maintain stable feedback oil pressure, a feedback damper connected in series with the feedback switch valve 11 is also provided in the working feedback oil circuit. The main feedback port K can also be connected to a pressure sensor 13 and an electro-proportional relief valve 10. The pressure sensor 13 measures the real-time system pressure, and adjusting the current value of the proportional electromagnet Y5 of the electro-proportional relief valve 10 adjusts the pressure value of the main feedback port K, thereby adjusting the main pump's flow output and actual oil supply pressure, forming a flexibly adjustable constant pressure oil source.

[0054] Both the cartridge-type directional valve 15 and the feedback switching valve 11 are electromagnetic directional valves, which facilitates targeted control by the electronic control system according to different operating conditions. Of course, those skilled in the art will understand that in other embodiments, they can also be adapted to be hydraulically controlled directional valves.

[0055] In this embodiment, the main feedback port K, main inlet port P, and main return port T0 of the constant flow control valve assembly are each connected to a pump quick-connect fitting 16 for connecting to the hydraulic pump circuit. (See also...) Figure 2 Thus, the three quick-connect couplings on the three oil lines allow for easy connection to... Figure 4 The variable pump is shown with three connecting oil circuits. In other words, the high-pressure, return, and feedback oil circuits of the subsystem of the boom luffing cylinder 1 can be directly connected to the existing hydraulic system of the whole machine without modifying the original system.

[0056] Based on the aforementioned constant flow control valve assembly, this application further discloses a secondary arm control module. For example... Figure 2 As shown, a specific embodiment of the auxiliary arm control module includes:

[0057] The aforementioned constant flow control valve group and main directional valve 7 have an inlet P1 on one side connected to the main outlet A of cartridge valve 12, a return port T1 on one side connected to the main return port T0 of the constant flow control valve group, and a working port on the other side of the main directional valve 7 used to connect to control the auxiliary boom luffing cylinder 1.

[0058] As can be seen, the above-mentioned constant flow control valve group and main directional valve 7 can be integrated into a secondary boom control module for controlling the secondary boom luffing cylinder. When in use, it only needs to be connected to the hydraulic pump and the secondary boom luffing cylinder 1 of the whole machine hydraulic system, which is simple and convenient to operate.

[0059] In this embodiment, the auxiliary boom control module may include:

[0060] Accumulator 9 is hydraulically connected to the oil inlet P1 of the main directional valve 7;

[0061] The energy storage switch valve 8 is used to control the oil circuit connection between the energy storage device 9 and the oil inlet P1 of the main directional valve 7.

[0062] The system utilizes an accumulator switch valve 8 and an accumulator 9 to form a high-pressure backup oil source, maintained at port P1 of the main directional valve 7. Since the pipeline between the main directional valve 7 and the cylinder is short, pressurized oil can immediately enter the corresponding cylinder cavity to push the piston rod out or retract as soon as the solenoid valve is energized, resulting in a timely and rapid response. During the start-up process, the accumulator 9 absorbs and eliminates flow fluctuations caused by pump flow pulsations, system load changes, or other factors, ensuring stable and continuous flow output. Throughout the start-up process, the operation remains smooth. An accumulator switch valve 8 is installed before the accumulator 9. The system pressure is measured by a pressure sensor 13, which controls the opening and closing of the accumulator switch valve 8. This ensures a stable and reliable oil source while allowing flexible control over the degree of accumulator 9's involvement in the system's operation.

[0063] See Figure 2 The main directional valve 7 has a first working port A1 for hydraulically connecting the rodless chamber of the auxiliary boom luffing cylinder 1 and a second working port A2 for hydraulically connecting the rod chamber of the auxiliary boom luffing cylinder 1. The second working port A2 is connected to an overflow valve 6.

[0064] Figure 2 The overflow valve 6 is connected between the second working port A2 and the return port T0 of the main directional valve 7, and can limit the maximum oil pressure entering the rod chamber of the cylinder through the second working port A2. See [link to relevant documentation]. Figure 3 Furthermore, during the bending process, the use of a constant pressure source and the pressure-splitting liquid bridge (which will be discussed later) can ensure the stability of the opening pressure of the balance valve 2, thereby ensuring the stability of the balance valve orifice and preventing it from being affected by changes in load pressure. In contrast, existing technologies are prone to vibration during the bending process.

[0065] The main directional valve 7 has a first hose reel 5 installed in the connecting pipe between the oil inlet P1 and the oil return port T1 on one side, and a second hose reel 4 installed in the connecting pipe between the working oil inlet on the other side. The outer end of the second hose reel 4 is equipped with a quick-connect coupling 3 for connecting to the hydraulic cylinder circuit. The quick-connect coupling 3 allows for direct and convenient connection to the auxiliary boom luffing cylinder 1.

[0066] Based on the aforementioned boom luffing cylinder 1, this application also discloses a complete hydraulic system. For example... Figure 3 As shown, a specific embodiment of the overall hydraulic system includes:

[0067] The aforementioned auxiliary boom control module; and

[0068] The auxiliary boom luffing cylinder 1 is connected to the working oil port of the main directional valve 7.

[0069] The auxiliary boom control module is connected to the auxiliary boom luffing cylinder 1 via the cylinder quick-change connector 3, and is also connected to the load-sensitive oil pump 17 of the main system via the pump quick-change connector 16. Thus, the subsystem of the auxiliary boom luffing cylinder 1 can be connected to the whole machine hydraulic system.

[0070] To enable connection with the load-sensitive oil pump 17 of the main system, the overall hydraulic system also includes:

[0071] Load-sensitive oil pump 17 and main valve 18, the load-sensitive oil pump 17 is used to pump hydraulic oil toward the main valve 18 and the main oil inlet P of the constant flow control valve group respectively;

[0072] Shuttle valve 19 has its first comparison port connected to the feedback port of main valve 18, and its second comparison port connected to the main feedback port K of constant flow control valve group. The outlet port of shuttle valve 19 is connected to the pump feedback port of load-sensitive oil pump 17.

[0073] The main valve 18 is typically a multi-way valve, which can be used to control multiple action units or working attachments. When the load-sensitive oil pump 17 (also known as the main pump) supplies hydraulic oil to both the main valve 18 and the auxiliary boom control module, in order to control the pump displacement, the pressure at the feedback port of the main valve 18 needs to be compared with the pressure at the main feedback port K of the auxiliary boom control module through the shuttle valve 19. The larger pressure is fed back to the pump feedback port of the variable pump, thereby adjusting the pumping oil volume.

[0074] The auxiliary boom luffing cylinder 1 includes a balance valve 2 installed in the rodless chamber working oil circuit and used for locking the rodless chamber oil. The balance valve 2 includes a balance valve core 21. The control port of the balance valve core 21 is connected to the rod chamber working oil circuit through a pilot oil circuit with an inlet damper 22 and to the low-pressure side of the rodless chamber working oil circuit through a bypass oil circuit with a bypass damper 23.

[0075] The balance valve 2 can be integrated into the cylinder of the auxiliary boom luffing cylinder 1. By setting the inlet damper 22 and the bypass damper 23, a pressure-dividing structure can be formed. Under the condition of constant total pressure (limited by the overflow valve 6), the pressure at the opening of the balance valve is also constant. In this way, no matter how the load changes, the opening of the balance valve is stable, eliminating the generation of vibration from the source and ensuring the smooth and reliable lowering action of the auxiliary boom.

[0076] Construction machinery with jib and jib luffing cylinder 1 comes in various types, typically cranes as described below, but the above-mentioned complete hydraulic system can also be applied to other construction machinery, such as pumps, etc.

[0077] The following section uses a crane and its jib and jib luffing cylinder 1 as examples to illustrate this application.

[0078] The crane uses a hydraulic cylinder (i.e., jib luffing cylinder 1) to directly control the luffing angle of the jib. The extension and retraction of the cylinder directly controls the luffing angle of the jib, and the working torque is borne by the locking chamber of the cylinder during operation. The luffing angle of the jib is directly controlled by jib luffing cylinder 1, and the rodless chamber of the cylinder is the working pressure chamber, supporting the jib and lifting heavy objects.

[0079] The constant flow control valve group and jib control module of this application can be connected to the overall hydraulic system of the crane, such as the upper hydraulic system of the crane. They can be used as a subsystem of the general hydraulic system of a truck crane and can be easily connected to the original system to expand the functions and realize the control of the jib luffing action.

[0080] The auxiliary boom luffing cylinder 1 has multiple operating states. Regardless of the state, the high-pressure oil is supplied by the main pump of the machine (i.e., the load-sensitive oil pump 17). The pressure signal controlling the high-pressure oil flow rate is given by comparing the load pressure from the feedback oil circuit with the pump inlet pressure. Figure 4 As shown.

[0081] The load-sensitive oil pump 17 not only supplies oil to the auxiliary boom luffing cylinder 1 and its system, but also supplies oil to the crane's conventional operations (such as main winch, auxiliary winch, luffing, and telescoping) through the main valve 18. Its output flow rate is determined by comparing the pressure at the pump feedback port with the main pump outlet pressure. The pressure at the pump feedback port is obtained through the oil circuit from the feedback port at the main valve end. Figure 4 The shuttle valve 19 shown is determined by comparing it with the feedback pressure signal of the auxiliary boom luffing system.

[0082] like Figure 5As shown, when the jib is not in use or the jib hook is not lifting, electromagnets Y1 and Y2 are de-energized. High-pressure oil enters the P port of the cartridge valve assembly via the pump quick-change connector 16. Most of the flow enters the side oil chamber of the cartridge valve 12, and a small portion flows through the first check valve 14 into the cartridge directional valve 15. Due to the de-energization of Y1, the pressurized oil directly enters the control chamber of the cartridge valve 12, pushing the cartridge valve core to cut off the oil path from the side oil port to the main oil outlet, completing self-locking. At the same time, due to the de-energization of Y2, there is no pressure signal output at the main feedback oil port K, and the feedback oil path is cut off. Since both the main oil path and the feedback oil path of the jib luffing system are cut off, there is no interference with the conventional operating system. That is, when the jib is not in use, the execution of other conventional actions of the crane is not affected.

[0083] like Figure 6 As shown, in the preparatory state of the auxiliary boom, the accumulator is filled with liquid. At this time, electromagnets Y1, Y2, and Y3 are energized, and electromagnet Y5 of the electroproportional relief valve 10 is at a high pressure value. At this time, the high-pressure oil from the main pump outlet enters the P port of the cartridge valve assembly through the pump quick-change connector 16, and then enters the side oil cavity of the cartridge valve 12. At this time, Y1 is energized, the solenoid valve is at the potential, and the pressure oil in the control chamber of the cartridge valve enters the main return oil port T0 of the cartridge directional valve 15 through this potential, and then connects with the main return oil circuit through the pipeline, and finally leads to the oil tank. The pressure is released, the cartridge valve core moves to the left, the valve port opens, and the oil circuit from the side oil port of the cartridge valve to the main oil outlet A is connected. The high-pressure oil passes smoothly and enters the first rubber hose drum 5 (which is a large drum). After being transported by the long rubber hose in the drum, it reaches the oil inlet of the main directional valve 7. At this time, another oil enters the accumulator switch valve 8. Since Y3 is energized, the solenoid valve works in the on position, and the oil enters the accumulator 9 through this position. In this way, the oil circuit between the main pump and the accumulator is unobstructed. Of course, the connection of the pipeline does not mean that the main pump will charge the accumulator. The relevant oil circuit also needs to feed the load pressure back to the main pump. The principle of the feedback oil circuit is as follows: when Y2 is energized, the feedback switch valve 11 works in the conducting position. The pressure oil of the main oil circuit passes through the damper, through the conducting position of the solenoid valve, to the main feedback oil port K, and then through the pipeline through the pump quick-change joint 16 and shuttle valve 19 to enter the load feedback port of the oil pump, which drives the swashplate of the main oil pump to increase the swing angle and increase the flow output of the main oil pump, thereby realizing the charging of the accumulator 9.

[0084] The accumulator filling pressure is controlled by the electro-proportional relief valve 10, such as... Figure 7As shown, the specific process is as follows: As the main pump fills the accumulator, the oil pressure inside the accumulator 9 continuously increases, and the feedback pressure also increases with the main pressure. When the pressure rises to the set value of the electro-proportional relief valve 10, the relief valve opens, limiting the feedback pressure to that set value, thereby limiting the pressure in the main oil circuit. At this time, the main oil circuit pressure is converted into an electrical signal by the pressure sensor 13 and enters the electrical control system, reminding the operator that the system has completed the preparations before action and can begin to execute the corresponding auxiliary boom action.

[0085] like Figure 8 As shown, after the aforementioned preparatory state, a stable high-pressure oil source (i.e., the main pump output oil pressure delivered by the accumulator 9 and the first hose reel 5) has been established at the oil inlet of the main directional valve 7. At this time, the electromagnet Y4b is energized, the solenoid valve operates in the right position, and the high-pressure oil from the oil inlet of the main directional valve 7 enters the working oil port A shown in the figure (i.e., Figure 3 The first working oil port A1), then through the pipeline and the second rubber hose drum 4 (a small drum), enters the balance valve 2, and finally enters the rodless chamber of the luffing cylinder 1, extending the cylinder piston rod to complete the boom lifting action.

[0086] When the hydraulic cylinder begins to move, with the switching of the main directional valve 7, although the main oil pump is still in a small displacement state and the output flow is not large, the oil in the accumulator 9 can quickly supply oil to the rodless chamber of the cylinder through the pipeline. Due to the absence of the limitation of the pipeline length in the first reel hose 5, the piston rod will be pushed out in a very short time, meaning that the auxiliary boom luffing action has excellent responsiveness. During the piston rod extension process, the presence of the accumulator 9, as an elastic element, can absorb and eliminate the flow pulsation of the oil pump itself and the variable process, ensuring the smoothness of the action.

[0087] like Figure 9 As shown, when the boom luffing action stops and heavy loads are being lifted, after the boom reaches the required luffing position, Y4b is de-energized, and the main directional valve 7 switches back to the neutral position. Since the neutral position function of the main directional valve 7 is Y-type, the pressure at the working port is directly released through the return oil port, and the cylinder action stops. Due to the locking effect of the balance valve 2, the oil in the rodless chamber is locked to support the weight of the boom and the load.

[0088] See Figure 10When the piston rod of the luffing cylinder retracts and the jib lowers, Y4a is energized, and the main directional valve 7 switches to the left position. The oil inlet of the main directional valve 7 is also connected to the accumulator 9 at this time. High-pressure oil flows through the second hose reel 4, one path directly into the rod chamber of the luffing cylinder, and the other path into the pilot port of the balance valve, opening the balance valve spool. This releases the oil in the rodless chamber, achieving the lowering action. Normally, this control method, which uses the pressure of the rod chamber of the cylinder to open the balance valve in the rodless chamber, has the disadvantage that the opening process is affected by the load pressure. When the pressure changes, vibration is prone to occur. Since the load inevitably changes during the lowering process of the jib, vibration is very likely to occur. Strong vibration of the jib during use is very detrimental to the safety of the load and the stability of the entire vehicle.

[0089] To overcome this shortcoming, combine Figure 10 , Figure 3 In this embodiment, a relief valve 6 is installed at the high-pressure working port (i.e., the rod chamber side of the cylinder) of the main directional valve 7 to limit the maximum pressure entering the rod chamber of the cylinder. The balance valve 2 in this embodiment includes a balance valve core 21 and a sequence valve connected in parallel. An inlet damper 22 is installed before the opening port (X port) of the balance valve core 21, and then a bypass damper 23 is installed at the opening port. These two dampers form a pressure-dividing structure. Under the condition that the total pressure is constant (limited by the relief valve 6), the pressure at the opening port of the balance valve is also constant. In this way, no matter how the load changes, the opening of the balance valve is stable, eliminating the generation of vibration from the source.

[0090] Of course, those skilled in the art will understand that the constant flow control valve group and auxiliary boom control module of this application can also be omitted. Instead, a single-joint valve can be added to the main valve 18, using an electro-hydraulic proportional directional valve to control the extension and retraction of the auxiliary boom luffing cylinder 1. This system can also be supplied with oil by a variable displacement piston pump. The LS port of the current proportional directional valve can send the load pressure back to the feedback port of the variable displacement pump through a pipeline, increasing the pump displacement and achieving system stability. Relying on the pilot current control of the proportional directional valve, a certain degree of precise flow output can be achieved. However, this alternative system has poor responsiveness and a long action delay.

[0091] In summary, the boom control module (or boom luffing system) of this application can share a main pump with the existing hydraulic system of the whole machine, without the need to add a high-pressure plunger pump, nor a power take-off port or a serial port for a large torque oil pump. The pump size and space usage are also more advantageous. The boom luffing system of this application can be directly connected to the existing hydraulic system as a sub-module using three quick-connect couplings without modifying the original system. In contrast, existing technologies require adjustments to the original system design, addition of components, and modification of pipelines, failing to achieve modular convenience and practicality. The system of this application has good responsiveness, especially in situations where the boom is extended for a long time. Through a preparatory working condition, a stable high-pressure source is established at the inlet of the main directional valve. The pipeline between the main directional valve and the cylinder is short; as soon as the solenoid valve is energized, pressurized oil can immediately enter the corresponding cylinder cavity, resulting in timely and rapid action. In contrast, existing technologies suffer from slow system response and long delays due to the long hoses inside the large drum. Furthermore, the system of this application exhibits high stability. During the boom lifting process, the presence of the accumulator, an elastic element, absorbs and eliminates flow fluctuations caused by pump flow pulsations, system load changes, or other factors, ensuring stable and continuous flow output. The entire lifting process is characterized by smooth operation. Additionally, the lowering process of the auxiliary boom luffing cylinder is smooth. During lowering, a constant pressure source combined with a pressure-sharing hydraulic bridge ensures stable pressure at the balance valve opening, thereby guaranteeing valve stability unaffected by load pressure changes.

[0092] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0093] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0094] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

Claims

1. A constant flow control valve assembly, used in the auxiliary boom control module of a crane, characterized in that, The constant flow control valve assembly includes: Cartridge valve (12), the main outlet (A) of the cartridge valve (12) is hydraulically connected to the inlet (P1) of the main directional valve (7) of the auxiliary boom control module. The cartridge directional valve (15) includes a working port on one side and a main return port (T0) and a directional valve inlet port (P0) on the other side, which are selectively connected to the working port. The working port is connected to the control port of the cartridge valve (12), and the directional valve inlet port (P0) is connected to the main inlet port (P) of the cartridge valve (12). Feedback switching valve (11) is used to control the pressure feedback of the main oil inlet (P) to the oil pump. The feedback switching valve (11) is set in the working feedback oil circuit connected between the main oil inlet (P) of the cartridge valve (12) and the main feedback oil port (K) of the constant flow control valve group.

2. The constant flow control valve assembly according to claim 1, characterized in that, The main feedback port (K), main inlet port (P), and main return port (T0) of the constant flow control valve group are respectively connected to pump quick-change connectors (16) for connecting to the hydraulic pump circuit.

3. The constant flow control valve assembly according to claim 1 or 2, characterized in that, An oil bypass circuit is connected between the oil inlet (P0) of the directional valve and the main oil inlet (P) of the cartridge valve (12). The oil bypass circuit is provided with a first check valve (14). The first check valve (14) is configured to allow hydraulic oil to flow from the main oil inlet (P) to the oil inlet (P0) of the directional valve and to cut off the flow in the reverse direction.

4. The constant flow control valve assembly according to claim 3, characterized in that, The main feedback port (K) is connected to a pressure sensor (13) and an electro-proportional relief valve (10); and / or, the working feedback oil circuit is also provided with a feedback damper connected in series with the feedback switch valve (11); and / or, the cartridge directional valve (15) and the feedback switch valve (11) are both electromagnetic directional valves.

5. The constant flow control valve assembly according to claim 3, characterized in that, A supplementary connection oil circuit is provided between the oil inlet (P0) of the reversing valve and the main oil outlet (A) of the cartridge valve (12). The supplementary connection oil circuit is provided with a second check valve (14'). The second check valve (14') is configured to allow hydraulic oil to flow from the oil outlet of the cartridge valve (12) to the oil inlet (P0) of the reversing valve and to cut off in the reverse direction.

6. A secondary boom control module, characterized in that, The auxiliary arm control module includes: The constant flow control valve assembly according to any one of claims 1 to 5; and The main directional valve (7) has an inlet (P1) on one side connected to the main outlet (A) of the cartridge valve (12), and a return port (T1) on one side connected to the main return port (T0) of the constant flow control valve group. The working port on the other side of the main directional valve (7) is used to connect to the control arm luffing cylinder (1).

7. The auxiliary boom control module according to claim 6, characterized in that, The auxiliary arm control module includes: Accumulator (9) is hydraulically connected to the oil inlet (P1) of the main directional valve (7). An energy storage switch valve (8) is used to control the oil circuit connection between the energy storage device (9) and the oil inlet (P1) of the main directional valve (7).

8. The auxiliary boom control module according to claim 6, characterized in that, The working ports of the main directional valve (7) include a first working port (A1) for hydraulically connecting the rodless chamber of the auxiliary boom luffing cylinder (1) and a second working port (A2) for hydraulically connecting the rod chamber of the auxiliary boom luffing cylinder (1). The second working port (A2) is connected to an overflow valve (6).

9. The auxiliary boom control module according to claim 8, characterized in that, The main directional valve (7) has a first hose reel (5) in the connecting pipe between the oil inlet (P1) and the oil return port (T1) on one side, and a second hose reel (4) in the connecting pipe between the working oil inlet on the other side. The outer end of the second hose reel (4) is provided with a quick-change connector (3) for connecting the oil circuit of the oil cylinder.

10. The hydraulic system of the whole machine, characterized in that, The overall hydraulic system includes: The auxiliary boom control module according to any one of claims 6 to 9; and The auxiliary boom luffing cylinder (1) is connected to the working oil port of the main directional valve (7).

11. The hydraulic system of the whole machine according to claim 10, characterized in that, The auxiliary boom luffing cylinder (1) includes a balance valve (2) installed in the rodless chamber working oil circuit and used for locking the rodless chamber oil. The balance valve (2) includes a balance valve core (21). The control port of the balance valve core (21) is connected to the rod chamber working oil circuit through a pilot oil circuit with inlet damping (22) and to the low-pressure side of the rodless chamber working oil circuit through a bypass oil circuit with bypass damping (23).

12. The hydraulic system of the whole machine according to claim 10, characterized in that, The overall hydraulic system also includes: Load-sensitive oil pump (17) and main valve (18), wherein the load-sensitive oil pump (17) is used to pump hydraulic oil toward the main valve (18) and the main inlet (P) of the constant flow control valve group, respectively; The shuttle valve (19) has a first comparison port connected to the feedback port of the main valve and a second comparison port connected to the main feedback port (K) of the constant flow control valve group. The outlet of the shuttle valve (19) is connected to the pump feedback port of the load-sensitive oil pump (17).

13. A crane, characterized in that, The crane includes the complete hydraulic system according to any one of claims 10 to 12.

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