Hydraulic control system and tractor ladder truck

Abstract

The utility model relates to hydraulic control technical field provides a kind of hydraulic control system and tractor ladder truck, and hydraulic control system includes power component, manual reversing valve assembly, execution component and electric control reversing valve assembly;Manual reversing valve assembly includes first state, second state and third state;In first state, manual reversing valve assembly and execution component are communicated positively, and manual reversing valve assembly and electric control reversing valve assembly are disconnected;In second state, manual reversing valve assembly and execution component are communicated reversely, and manual reversing valve assembly and electric control reversing valve assembly are disconnected;In third state, manual reversing valve assembly and execution component are disconnected, and manual reversing valve assembly and electric control reversing valve assembly are communicated.The utility model provides a kind of hydraulic control system, and operating priority control is automatically realized by mechanical structure, and the dangerous situation of out of control can be effectively avoided in the case where electric control reversing valve assembly appears fault.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic control technology, and in particular to a hydraulic control system and a traction ladder truck. Background Technology

[0002] In existing technologies, to meet the dual requirements of automated electronic control and emergency manual operation of equipment, a common solution is to connect an electrically controlled valve group and a manually controlled valve group in parallel in the main hydraulic circuit between the hydraulic pump and the actuator (such as a hydraulic cylinder or hydraulic motor). The electrically controlled valve group typically consists of components such as solenoid directional valves, which receive electrical signal commands from the controller to switch the oil circuit, enabling remote or automatic control of the actuator. The manually controlled valve group typically consists of manual directional valves, allowing operators to switch the oil circuit directly by manipulating mechanisms such as handles, enabling local manual control of the actuator.

[0003] However, due to the complex and variable on-site conditions, and the possibility of operator negligence or misjudgment of system status, both the electrically controlled valve group and the manually controlled valve group may be simultaneously open during operation. When both valve groups are open at the same time, the pressurized oil from the oil pump will act on the actuators simultaneously through two parallel oil circuits, causing conflicts and confusion between the control commands and power inputs received by the actuators. This power confusion can lead to malfunctions in the actuators and loss of equipment control, or even create abnormal high pressure or flow surges within the hydraulic system, damaging core components such as the hydraulic valve group, oil pump, and actuators, and potentially even damaging the entire mechanical equipment, posing a serious threat to production safety and equipment reliability. Utility Model Content

[0004] The first aspect of this utility model provides a hydraulic control system to solve the defect in the prior art that two valve groups may be opened at the same time. It automatically realizes operation priority control through mechanical structure. If manual operation is started during the electric control operation, the hydraulic control system will immediately switch to manual mode and interrupt the electric control oil circuit. This can effectively avoid the loss of control and dangerous situation caused by the failure of the electric control directional valve assembly.

[0005] The second aspect of this utility model provides a towed ladder truck.

[0006] The hydraulic control system provided by this utility model includes: Power components are used to supply hydraulic fluid; A manual directional valve assembly is connected downstream of the power assembly, and the downstream of the manual directional valve assembly is connected to the oil tank. The manual directional valve assembly includes a first state, a second state, and a third state. An actuator, connected downstream of the manual directional valve assembly, is used to convert hydraulic energy into mechanical energy for output; An electrically controlled directional valve assembly is connected to the oil tank; in a first state, the manual directional valve assembly is in forward communication with the actuation component, and the manual directional valve assembly is disconnected from the electrically controlled directional valve assembly; in a second state, the manual directional valve assembly is in reverse communication with the actuation component, and the manual directional valve assembly is disconnected from the electrically controlled directional valve assembly; in a third state, the manual directional valve assembly is disconnected from the actuation component, and the manual directional valve assembly is connected to the electrically controlled directional valve assembly.

[0007] According to the hydraulic control system provided by this utility model, the electrically controlled directional valve assembly includes: A first electrically controlled directional valve is connected between the manual directional valve assembly and the actuation assembly; A proportional directional valve is connected between the manual directional valve assembly and the oil tank. The proportional directional valve is used to control the flow rate of hydraulic oil in the first electrically controlled directional valve.

[0008] According to the hydraulic control system provided by this utility model, the electrically controlled directional valve assembly further includes a valve body, and the valve body is provided with a mounting part; The first electrically controlled directional valve is detachably inserted into the mounting portion, and / or the proportional directional valve is detachably inserted into the mounting portion.

[0009] According to the hydraulic control system provided by this utility model, the manual directional valve assembly includes multiple six-way valves, each of which is provided with an execution position and a manual / electric conversion position, and the execution position of each of the six-way valves is respectively connected to the execution assembly. The manual / electric switching positions of all the six-way valves are connected in series, and each manual / electric switching position of the six-way valve can independently disconnect the connection between the electric directional valve assembly and the power assembly.

[0010] According to the hydraulic control system provided by this utility model, the execution component includes a plurality of execution parts, each of the execution parts including a hydraulic cylinder or a hydraulic motor; Multiple actuators are connected to multiple six-way valves in a one-to-one correspondence, and at least one pair of the multiple pairs of actuators and six-way valves are connected to the electrically controlled directional valve assembly.

[0011] The towed ladder truck provided by this utility model includes a vehicle body and a hydraulic control system as described in any one of the above. The execution component includes: A luffing cylinder is connected to the manual directional valve assembly. The luffing cylinder is used to control the angle between the ladder arm of the vehicle body and the ground. A rotary hydraulic motor is connected to the manual directional valve assembly, and the rotary hydraulic motor is used to control the rotation angle of the ladder arm of the vehicle body; A track telescopic hydraulic motor is connected to the manual reversing valve assembly, and the track telescopic hydraulic motor is used to control the extension and retraction of the ladder arm of the vehicle body; The material lifting hydraulic motor is connected to the manual reversing valve assembly and the electronically controlled reversing valve assembly. The material lifting hydraulic motor is used to control the raising or lowering of the material platform of the vehicle body.

[0012] According to the towable ladder truck provided by this utility model, the ladder arm is provided with a first position detection element, a second position detection element, a third position detection element and a fourth position detection element at intervals along the length direction; the electrically controlled reversing valve assembly is electrically connected to the first position detection element, the second position detection element, the third position detection element and the fourth position detection element respectively; The first position detection device is used to determine the initial position of the material platform; the second position detection device is used to determine the rising acceleration position or the falling deceleration position of the material platform; the third position detection device is used to determine the rising deceleration position or the falling acceleration position of the material platform; and the fourth position detection device is used to determine the preset target position of the material platform.

[0013] The towed ladder truck provided by this utility model also includes: A one-way valve, wherein the oil outlet of the one-way valve is connected to the first end of the track telescopic hydraulic motor, and the oil inlet of the one-way valve is connected to the second end of the track telescopic hydraulic motor; The balance valve has its pressure port connected to the manual directional valve assembly, its return port connected to the first end of the track telescopic hydraulic motor, and the outlet port of the check valve connected to the return port of the balance valve. The pilot control port of the balance valve is connected to the second end of the telescopic hydraulic motor.

[0014] According to the towing ladder truck provided by this utility model, the electrically controlled reversing valve assembly further includes: The second electrically controlled directional valve is connected at one end to the oil tank and at the other end to the pressure oil port of the balance valve; The third electrically controlled directional valve is connected at one end to the oil tank and at the other end to the oil inlet of the check valve.

[0015] The towed ladder truck provided by this utility model also includes: An upper limit switch is electrically connected to the second electrically controlled directional valve. The upper limit switch is used to determine the extension limit position of the ladder arm. When the upper limit switch is triggered, the second electrically controlled directional valve connects the manual directional valve assembly and the oil tank. The lower limit component is electrically connected to the third electrically controlled directional valve. The lower limit component is used to determine the shortening limit position of the ladder arm. When the lower limit component is triggered, the third electrically controlled directional valve connects the manual directional valve assembly and the oil tank.

[0016] In the hydraulic control system provided by this utility model, a physical mutual exclusion mechanism for the operation channel is established at the hydraulic level through the three-state oil circuit design of the manual directional valve assembly. Specifically, when manual operation is activated (first or second state), the bridge port oil circuit between the manual directional valve assembly and the electronic directional valve assembly is forcibly closed, cutting off the pressure oil supply of the electronic directional valve assembly from the source, and completely avoiding the possibility of the manual and electronic control systems supplying oil to the actuator at the same time.

[0017] Compared to the parallel valve group schemes in the background technology that rely on operator judgment, the hydraulic control system provided by this utility model automatically realizes operation priority control through mechanical structure. If manual operation is initiated during the electric control operation, the hydraulic control system will immediately switch to manual mode and interrupt the electric control oil circuit, forming a fail-safe mechanism. Taking a towed ladder truck as an example, in the event of a failure of the electric control directional valve assembly, the emergency take-off equipment can be manually operated, which can effectively avoid loss of control and dangerous situations caused by the failure of the electric control directional valve assembly, and can effectively protect the personal safety of operators and improve the safety of on-site operations. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the hydraulic principle of the hydraulic control system according to an embodiment of the present invention.

[0020] Figure 2 yes Figure 1 A schematic diagram of the hydraulic principle in manual control mode.

[0021] Figure 3 yes Figure 1 One of the schematic diagrams of hydraulic principle in electronic control mode.

[0022] Figure 4 yes Figure 1 The second schematic diagram of hydraulic principle in electronic control mode.

[0023] Figure 5 This is a structural schematic diagram of the towed ladder truck provided in this embodiment of the utility model.

[0024] Figure label: 100: Power unit; 200: Fuel tank; 300: Manual directional valve assembly; 310: Six-way valve; 400: Actuation component; 410: Luffing cylinder; 420: Rotary hydraulic motor; 430: Track telescopic hydraulic motor; 431: Check valve; 432: Balance valve; 440: Material lifting hydraulic motor; 500: Electro-optical directional valve assembly; 510: First electro-optical directional valve; 520: Proportional directional valve; 530: Second electro-optical directional valve; 540: Third electro-optical directional valve; 600: Vehicle body; 610: Ladder arm; 620: Material platform. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0026] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" 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. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0027] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0028] 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 the embodiments 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.

[0029] Figure 1 This is a schematic diagram of the hydraulic principle of the hydraulic control system according to an embodiment of the present invention.

[0030] See Figure 1 The first aspect of this utility model provides a hydraulic control system; the hydraulic control system includes a power component 100, a manual directional valve assembly 300, an actuator 400, and an electronically controlled directional valve assembly 500. The power component 100 is used to provide high-pressure hydraulic oil. The specific form of the power component 100 can be adapted to the actual situation. For example, the power component 100 can be a structure in which a prime mover drives a hydraulic pump. The prime mover can be an electric motor or an internal combustion engine, and the hydraulic pump can be a gear pump, a piston pump, or other types.

[0031] It should be noted that "downstream" or "upstream" refers to the direction of energy transmission along the hydraulic circuit. The side of a component with higher energy is "upstream," and the side with lower energy is "downstream." For example, the side of the manual directional valve assembly 300 facing the power assembly 100 is used to receive high-pressure hydraulic oil supplied by the power assembly 100. Therefore, the side of the manual directional valve assembly 300 facing the power assembly 100 is called the upstream of the manual directional valve assembly 300. Similarly, the side of the manual directional valve assembly 300 facing the actuation assembly 400 is called the downstream of the manual directional valve assembly 300. Other components in this article can be understood in the same way. The above definitions of "downstream" or "upstream" are only illustrative explanations given for the clarity of this utility model patent and are not intended to limit the specific embodiments of this utility model.

[0032] The manual directional valve assembly 300 is located downstream of the power assembly 100 and connected to the oil tank 200. The manual directional valve assembly 300 can be a manual multi-way directional valve, such as a manual three-position six-way directional valve. The actuator 400 is connected downstream of the manual directional valve assembly 300. The actuator 400 is used to convert hydraulic energy into mechanical energy for output. For example, the actuator 400 can be a hydraulic motor, which can convert hydraulic energy into rotational motion.

[0033] The electrically controlled directional valve assembly 500 is connected downstream of the manual directional valve assembly 300 and is connected to the oil tank 200. The electrically controlled directional valve assembly 500 can be a solenoid valve, such as a three-position four-way solenoid valve or a two-position two-way solenoid valve. The electrically controlled directional valve assembly 500 can remotely control the actuator 400. For example, during the control of the material trolley of the traction ladder truck, the operator can remotely control the electrically controlled directional valve assembly 500 through a handle, thereby remotely controlling the rise and fall of the material platform 620. Optionally, the rising and falling speed can also be remotely controlled through the electrically controlled directional valve assembly 500.

[0034] Figure 2 yes Figure 1 A schematic diagram of the hydraulic principle in manual control mode; Figure 3 yes Figure 1 One of the schematic diagrams of hydraulic principle in electronic control mode; Figure 4 yes Figure 1 The second schematic diagram of hydraulic principle in electronic control mode.

[0035] See Figures 2 to 4 In this embodiment, the manual directional valve assembly 300 includes three operating states.

[0036] First state: The manual reversing valve assembly 300 connects the power assembly 100 and the actuation assembly 400 in the forward direction (e.g., Figure 2 The hydraulic oil flows through port A1 to the rodless chamber of the hydraulic cylinder, and at the same time disconnects from the electrically controlled directional valve assembly 500. During this process, the manual directional valve assembly 300 controls the operation of the execution assembly 400, and no hydraulic oil flows in the electrically controlled directional valve assembly 500.

[0037] Second state: The manual directional valve assembly 300 reverses the connection between the power assembly 100 and the actuator 400 (e.g., oil flows to the rod chamber of the hydraulic cylinder through port B1), and similarly disconnects the connection with the electronic directional valve assembly 500. During this process, the manual directional valve assembly 300 controls the operation of the actuator 400, and no hydraulic oil flows in the electronic directional valve assembly 500.

[0038] Third state: The manual directional valve assembly 300 is disconnected from the actuator assembly 400, and instead connected to the electrically controlled directional valve assembly 500 through the bridge port C (e.g., Figure 3 and Figure 4 The hydraulic oil flows through port C to the electrically controlled directional valve assembly 500. At this time, the hydraulic oil automatic force assembly 100 is activated, flows through the manual directional valve assembly 300 to the electrically controlled directional valve assembly 500. The electrically controlled directional valve assembly 500 realizes the operation control of the actuator 400 by connecting or disconnecting its connection with the actuator 400.

[0039] It should be noted that, since valve assemblies can generally reverse the direction of the oil circuit, for ease of description, this article defines "forward connection" and "reverse connection." "Forward connection" and "reverse connection" only express the two flow directions of hydraulic oil through the components. Taking the luffing cylinder 410 and the manual directional valve assembly 300 as examples, when the manual directional valve assembly 300 and the luffing cylinder 410 are connected, and the piston of the luffing cylinder 410 is in the process of extending, then the manual directional valve assembly 300 and the luffing cylinder 410 are in "forward connection." After the position of the valve core inside the manual directional valve assembly 300 changes, the manual directional valve assembly 300 and the luffing cylinder 410 are connected. When the piston of the luffing cylinder 410 is in the retraction motion, the manual directional valve assembly 300 and the hydraulic cylinder are in "reverse connection". The definitions of "forward connection" and "reverse connection" are only illustrative explanations given for the purpose of clear expression in this utility model patent, and are not intended to limit the specific embodiments of this utility model. In some cases, "forward connection" can also correspond to "piston in retraction motion", and "reverse connection" can also correspond to "piston in extension motion". The "forward connection" and "reverse connection" of other components, such as the rotary hydraulic motor 420, the track telescopic hydraulic motor 430 and the material lifting hydraulic motor 440, can be compared by analogy.

[0040] In use, when the operator moves the manual directional valve assembly 300 to the first or second position (e.g., by pushing the valve stem), the high-pressure oil directly drives the actuator (e.g., the luffing cylinder 410 extends or retracts), and the oil flows back to the oil tank 200 through the return port of the manual directional valve assembly 300. At this time, the oil circuit at the bridge port C is closed, and the electronically controlled directional valve assembly 500 is in a disabled state due to the lack of oil input.

[0041] When the manual directional valve assembly 300 is in the third state, the oil enters the electrically controlled directional valve assembly 500 through the bridge port C of the manual directional valve assembly 300. At this time, the opening and closing state of the electrically controlled directional valve assembly 500 is controlled by an electrical signal. If the solenoid valve is energized, the oil flows through the electrically controlled directional valve assembly 500 to the actuator (such as driving the hydraulic motor to rotate); if the solenoid valve is not energized, the oil flows back to the oil tank 200 through the electrically controlled directional valve assembly 500.

[0042] If the manual directional valve assembly 300 is operated at this time (switched to the first or second state), the oil circuit of the bridge port C is immediately cut off, the oil supply of the electronically controlled directional valve assembly 500 is interrupted, and the electronic operation is forcibly terminated.

[0043] See Figures 1 to 4 It is understood that in the hydraulic control system provided by this utility model embodiment, a physical mutual exclusion mechanism of the operation channel is established at the hydraulic level through the three-state oil circuit design of the manual directional valve assembly 300. Specifically, when manual operation is activated (first or second state), the bridge port oil circuit between the manual directional valve assembly 300 and the electronically controlled directional valve assembly 500 is forcibly closed, cutting off the pressure oil supply of the electronically controlled directional valve assembly 500 from the source, and completely avoiding the possibility of the manual and electronically controlled systems supplying oil to the actuator at the same time.

[0044] Compared to the parallel valve group schemes in the background technology that rely on operator judgment, the hydraulic control system provided in this utility model embodiment automatically realizes operation priority control through mechanical structure. If manual operation is initiated during the electric control operation, the hydraulic control system will immediately switch to manual mode and interrupt the electric control oil circuit, forming a fail-safe mechanism. Taking a towed ladder truck as an example, in the event of a failure of the electric control directional valve assembly 500, the emergency take-off device can be manually operated, which can effectively avoid the loss of control and dangerous situation caused by the failure of the electric control directional valve assembly 500, and can effectively protect the personal safety of operators and improve the safety of on-site operations.

[0045] Continue reading Figure 3 and Figure 4 In an optional embodiment of this utility model, the electrically controlled directional valve assembly 500 includes a first electrically controlled directional valve 510 and a proportional directional valve 520. The first electrically controlled directional valve 510 is connected between the manual directional valve assembly 300 and the actuation assembly 400. The first electrically controlled directional valve 510 is used to connect or disconnect the connection between the electrically controlled directional valve assembly 500 and the actuation assembly 400. The first electrically controlled directional valve 510 can be an existing component such as a three-position four-way solenoid directional valve.

[0046] The proportional directional valve 520 is connected between the manual directional valve assembly 300 and the oil tank 200. The upstream of the proportional directional valve 520 is connected to the upstream of the first solenoid directional valve 510. The proportional directional valve 520 controls the flow rate through the first solenoid directional valve 510 by adjusting its valve opening. The proportional directional valve 520 can be an electro-hydraulic proportional valve or a proportional solenoid valve, etc.

[0047] In use, when the manual directional valve assembly 300 is in the third state, high-pressure oil enters the electronically controlled directional valve assembly 500 through the bridge port C. When the first electronically controlled directional valve 510 is energized (e.g., by a controller signal), the oil circuit is connected (e.g., P5-B5 and T5-A5 are connected), allowing the oil to drive the actuator. If the first electronically controlled directional valve 510 is de-energized, the oil circuit is cut off (e.g., P5-B5 and T5-A5 are disconnected), and the electronic operation immediately terminates.

[0048] When the first electrically controlled directional valve 510 is energized ( Figure 4 As shown), when a small current is input to the proportional directional valve 520, the Pc-Tc oil passage opens wide, and most of the oil flows directly back to the oil tank 200 through the proportional directional valve 520. A small amount of oil enters the first electrically controlled directional valve 510, and the actuator 400 operates at low speed (e.g., the material lifting hydraulic motor 440 rotates slowly). When the input current to the proportional directional valve 520 increases, the throttling effect of the Pc-Tc oil passage is enhanced, the amount of oil flowing to the first electrically controlled directional valve 510 increases, and the actuator 400 accelerates. When the first electrically controlled directional valve 510 is not energized ( Figure 3 As shown in the figure, the hydraulic oil returns directly to the oil tank 200 through the proportional directional valve 520.

[0049] During the above process, when the manual directional valve assembly 300 is manually operated, the oil circuit of the bridge port C is forcibly cut off, the proportional directional valve 520 and the first electronically controlled directional valve 510 lose pressure at the same time, and the electronic control function fails.

[0050] See Figure 3 and Figure 4 It is understood that in the hydraulic control system provided by this utility model embodiment, the throttling function of the proportional directional valve 520 can provide stepless flow regulation capability, overcoming the limitation of traditional switching valves that are only fully open or fully closed. Taking a traction ladder truck as an example, it can dynamically optimize the material lifting speed according to the load (such as low speed anti-sway under heavy load and high speed efficiency under light load). Secondly, the first electronically controlled directional valve 510, as an independent switch, gives the electronic control circuit the ability to start and stop quickly (such as immediately terminating the action in case of emergency power failure). The decoupling design with the speed regulation function of the proportional valve effectively reduces the system complexity. In addition, both valves are subject to the priority of manual operation. When manual intervention occurs, the physical cut-off of the oil circuit at the bridge port completely disables the electronically controlled directional valve assembly 500, effectively avoiding the power conflict caused by the parallel oil supply of dual valves in the background technology (such as abnormal cylinder vibration or motor overspeed).

[0051] In an optional embodiment of this utility model, the electrically controlled directional valve assembly 500 further includes a valve body, which has a mounting portion (such as a standard cartridge hole). The first electrically controlled directional valve 510 is mounted on the corresponding mounting portion using a detachable cartridge method. Optionally, the proportional directional valve 520 can also be mounted on the corresponding mounting portion using a detachable cartridge method, with its Pc port and Tc port respectively connected to the internal oil passage of the valve body. The cartridge method can be either threaded or snap-fit, and can be selected adaptively according to the actual situation.

[0052] During maintenance and replacement, after shutting down the hydraulic control system and depressurizing, disconnect the external wires and oil pipe joints of the proportional directional valve 520; unscrew the locking nut (or press the buckle) of the first solenoid directional valve 510 and pull the old valve core out of the mounting part; insert the new valve core along the mounting part, ensuring that the sealing ring is embedded in the valve body groove; tighten the nut again (or confirm that the buckle is reset), and connect the pipeline to complete the replacement; the valve body serves as an integrated oil circuit platform, and the inlet / outlet of the cartridge valve (first solenoid directional valve 510 or proportional directional valve 520) is automatically aligned with the internal flow channel through the mounting part. After being powered on, the proportional directional valve 520 still regulates the flow rate based on the principle described above.

[0053] Understandably, when the proportional directional valve 520 or the first electrically controlled directional valve 510 fails, it is not necessary to replace the entire valve assembly; only the individual cartridge valve needs to be disassembled for repair. This can effectively shorten downtime and reduce maintenance costs. Compared to traditional welded or bolted integrated valve assemblies, the cartridge structure avoids the cumbersome process of reconnecting dozens of oil pipes when disassembling the valve block, thus reducing the risk of misinstallation. Secondly, the valve body serves as a universal platform compatible with cartridge valves of different specifications. For example, the proportional valve can be replaced with different flow rate models, expanding the adaptability flexibility of the hydraulic control system.

[0054] Continue reading Figure 3 and Figure 4 In an optional embodiment of this utility model, the manual directional valve assembly 300 includes a plurality of six-way valves 310 (e.g., Figure 3 As shown in the diagram, each six-way valve 310 has two functional positions: the execution position, which connects the power assembly 100 to the corresponding execution assembly 400 (such as the rod chamber and rodless chamber of the hydraulic cylinder) to achieve manual control; and the manual-electric conversion position (i.e., the third state), which disconnects the connection with the execution assembly 400 and instead directs the hydraulic fluid to the series-connected electronic control circuit.

[0055] Among them, all the electric switching positions of the six-way valve 310 are connected in series (e.g. Figure 3 The cascaded oil circuit at the bridge outlet C forms the main electronically controlled oil circuit. When all six-way valves at position 310 are manually switched to the correct position, such as... Figure 2As shown, the oil flows sequentially through valve 1 → valve 2 → valve 3 → valve 4 → electrically controlled directional valve assembly 500; when any six-way valve 310 is switched to the execution position, its manual or electric switching position can independently cut off the electrically controlled oil circuit of the section where the valve is located (such as valve core displacement closure).

[0056] During implementation, in the initial state, all six-way valves 310 are in the manual / electric switching position, and the oil is transported to the electrically controlled directional valve assembly 500 through the series structure for electrical control operation; if the six-way valve 310 is operated to the actuation position (such as pushing the valve stem), the six-way valve 310 cuts off its own series oil circuit, and the oil is redirected to drive the corresponding actuation assembly 400; due to the existence of the cascade oil circuit, the series outlets of valves 2, 3, and 4 downstream of valve 1 are simultaneously cut off from oil, and the global electrical control function is immediately terminated.

[0057] It is understood that in the hydraulic control system provided by this utility model embodiment, each six-way valve 310 exclusively controls a single actuator, which can avoid mutual interference between multiple actuator operations. Secondly, when any six-way valve 310 switches to the actuator position, the electronic control oil circuit of its segment is physically cut off. Due to the series connection of the oil circuits, the downstream electronic control directional valve assembly 500 loses pressure as a whole. Compared with unrelated parallel valve groups, the hydraulic control system provided by this utility model embodiment can ensure that any manual operation forces a global shutdown of electronic control, avoiding the risk of multiple valves supplying oil simultaneously. In addition, when a single six-way valve 310 fails (such as valve core jamming), it can be isolated for repair without affecting the function of other valves, which can solve the problem of high maintenance costs in traditional multi-way valve integrated designs.

[0058] Continue reading Figures 1 to 4 In an optional embodiment of this utility model, the execution component 400 includes a plurality of execution parts, which may be selected as hydraulic cylinders or hydraulic motors, or other parts that can be driven by hydraulic oil.

[0059] The number of actuators is the same as the number of the aforementioned six-way valves 310. Each actuator corresponds to an independent six-way valve 310 for manual control. That is, each actuator and its corresponding six-way valve 310 are a separate pair. At least one pair of actuators and six-way valves 310 are connected to the hydraulic circuit of the six-way valve 310 and the electrically controlled directional valve assembly 500. Figures 1 to 4 As shown, from left to right, in the hydraulic circuit of the third group of six-way valve 310 and actuator, the outlet of the actuator is connected to both the six-way valve 310 and the electrically controlled directional valve assembly 500, and the inlet of the actuator is also connected to both the six-way valve 310 and the electrically controlled directional valve assembly 500.

[0060] For example, in one optional embodiment, the actuating components include a luffing cylinder 410, a rotary hydraulic motor 420, a track telescopic hydraulic motor 430, and a material lifting hydraulic motor 440. The six-way valve 310 corresponding to the material lifting hydraulic motor 440 is connected to the electrically controlled directional valve assembly 500, enabling remote electrical control of material lifting and lowering. The luffing cylinder 410, track telescopic hydraulic motor 430, and rotary hydraulic motor 420 are manually controlled only through their respective six-way valves 310. In another optional embodiment, the track telescopic hydraulic motor 430 can also be connected to the electrically controlled directional valve assembly 500 to accommodate the electrical control requirements of the ladder arm 610's extension and retraction. Specifically, the design can be adapted to the actual situation.

[0061] During operation, when the operator pushes the valve stem of a six-way valve 310, the hydraulic oil flows directly to the corresponding actuator, driving its action. For example, after pushing the valve stem of the six-way valve 310 corresponding to the luffing cylinder 410, the hydraulic oil enters the rodless chamber of the luffing cylinder 410, pushing the piston rod to extend and adjust the track angle; at this time, the bridge port passage of the six-way valve 310 is closed, and the electronic control oil circuit is cut off.

[0062] When not manually operated, hydraulic oil flows through the bridge port of the six-way valve 310 to the electrically controlled directional valve assembly 500. At this time, the electrically controlled directional valve assembly 500 can be activated via an electrical control signal (such as a handle command), driving the connected actuator (such as the material lifting hydraulic motor 440). The material lifting hydraulic motor 440 achieves stepless speed regulation under the adjustment of the proportional directional valve 520, allowing materials to rise and fall at different speeds. If any six-way valve 310 is manually operated during electrical control operation, the bridge port port immediately closes, the electrical control oil circuit is interrupted, and manual operation takes priority over system control to ensure operational safety.

[0063] It is understood that in the hydraulic control system provided by this utility model embodiment, independent control of each action is achieved through the one-to-one connection between the actuator and the six-way valve 310, avoiding mutual interference when multiple actions are performed in parallel. At the same time, high-frequency operating components (such as material hoisting) support remote speed regulation through the electronically controlled directional valve assembly 500, effectively improving operating efficiency and convenience; low-frequency operating components (such as track luffing) adopt low-cost manual control, reducing the overall system cost.

[0064] Compared to traditional proportional multi-way valve solutions, the hydraulic control system provided in this embodiment of the invention features a priority mechanism for manual operation that can immediately switch to manual mode in the event of an electrical control failure, effectively avoiding the risk of loss of control and improving operational safety.

[0065] Figure 5 This is a structural schematic diagram of the towed ladder truck provided in this embodiment of the utility model.

[0066] See Figure 1 and Figure 5 This utility model embodiment provides a towed aerial ladder truck, which includes a vehicle body 600 and the hydraulic control system described in any of the aforementioned embodiments. The difference from the aforementioned embodiments is that in this embodiment, the execution component 400 is directly implemented in the structure of the towed aerial ladder truck itself, such as the luffing cylinder 410, the rotary hydraulic motor 420, the track telescopic hydraulic motor 430, and the material lifting hydraulic motor 440.

[0067] Therefore, in this embodiment, the execution component 400 includes a luffing cylinder 410, a rotary hydraulic motor 420, a track telescopic hydraulic motor 430, and a material lifting hydraulic motor 440. The luffing cylinder 410 is connected to a manual directional valve assembly 300, and the angle between the ladder arm 610 and the ground is adjusted by extending and retracting the piston rod. For example, during the deployment phase, manually operating the valve rod in the manual directional valve assembly 300 can raise the ladder arm 610 from a horizontal position to a 60° working angle.

[0068] A rotary hydraulic motor 420 is connected to a manual directional valve assembly 300, driving the ladder arm 610 to rotate around the rotation center to align with the target position. It can be adjusted within a ±180° range using a cycloidal motor or a gear motor. A track telescopic hydraulic motor 430 is connected to the manual directional valve assembly 300, controlling the length of the ladder arm 610 by winding or releasing the wire rope. For example, during telescopic operation, the ladder arm 610 can extend from 5 meters to 15 meters.

[0069] The material lifting hydraulic motor 440 is connected to both the manual directional valve assembly 300 and the electrically controlled directional valve assembly 500 to control the lifting and lowering of the material platform 620. In specific applications, the material lifting hydraulic motor 440 drives the material platform 620 to move along the guide rail of the ladder arm 610 via a winch. It should be noted that the luffing cylinder 410 can be replaced with a double-acting hydraulic cylinder, and the rotary hydraulic motor 420 can be adapted to a planetary reduction mechanism to increase torque. That is, the specific models of components such as the luffing cylinder 410, rotary hydraulic motor 420, track telescopic hydraulic motor 430, and material lifting hydraulic motor 440 are not limited in this embodiment and can be selected adaptively according to actual conditions.

[0070] During use, after the hydraulic control system is started, the power unit 100 provides high-pressure oil to the manual directional valve assembly 300. When the valve rod corresponding to the luffing cylinder 410 is operated, the hydraulic oil enters the rodless chamber of the cylinder to push the piston rod out, and simultaneously closes the bridge passage to cut off the electronic control oil circuit. At this time, the angle of the ladder arm 610 increases. When the valve rod is operated in the opposite direction, the hydraulic oil enters the rod chamber and the angle of the ladder arm 610 decreases.

[0071] When the valve stem of the rotary hydraulic motor 420 is operated, the hydraulic oil drives the motor to rotate, causing the ladder arm 610 to rotate horizontally, for example, 90° from due north to due east. When the track telescopic hydraulic motor 430 is working, the hydraulic oil drives the drum to wind up and unwind the wire rope, causing the ladder arm 610 to extend or retract in sections.

[0072] In manual mode, the hydraulic motor 440 for material lifting directly controls the lifting speed of the material platform 620 via a valve stem. In electronic control mode, the operator sends a signal via a remote control handle, and the proportional valve adjusts the flow rate to achieve stepless speed regulation of the material platform 620. For example, it lifts at a high speed of 0.5 m / s under light load and automatically switches to a low speed of 0.2 m / s under heavy load. If any valve stem is manually pushed during electronic control operation, the bridge port passage is immediately closed, the electronic control oil circuit is interrupted, and the system is forced to switch back to manual mode.

[0073] It is understood that the towed aerial ladder truck provided in this embodiment of the present invention achieves low-cost manual control of deployment actions (luffing, slewing, telescoping) and automated electronic control coordinated operation of high-frequency material lifting actions by applying a hydraulic control system to the towed aerial ladder truck. Compared with traditional aerial ladder trucks using proportional multi-way valves, the towed aerial ladder truck provided in this embodiment of the present invention effectively reduces system costs by using a manual directional valve assembly 300 as the main valve. At the same time, it provides electronically controlled stepless speed regulation for material lifting through an independent electronically controlled directional valve assembly 500, which can improve work efficiency while ensuring safety. In addition, actions such as luffing, slewing, and telescoping are part of the deployment work before construction. Compared with electronic control operation, the direct operation of the corresponding valves by the operator allows for more intuitive feedback from the equipment, while avoiding the possibility of equipment overturning during deployment due to electrical faults.

[0074] The dual-path control design of the material lifting hydraulic motor 440 solves the problem of low operating efficiency of the pure manual solution. The priority mechanism of manual operation can immediately take over the equipment in the event of electrical control failure, which can avoid the risk of the material platform 620 falling out of control. It can demonstrate higher reliability and practicality in harsh environments such as dust and temperature differences at construction sites.

[0075] In an optional embodiment of this utility model, a first position detection element, a second position detection element, a third position detection element, and a fourth position detection element are sequentially and spaced apart along the length of the ladder arm 610 of the towed aerial ladder truck. The first position detection element is located at the bottom of the ladder arm 610 and is used to determine the initial position of the material platform 620 (e.g., the position where the material platform 620 is completely lowered to the ground); the fourth position detection element is located at the top of the ladder arm 610 and is used to determine the preset target position of the material platform 620 (e.g., the highest working point that the material platform 620 needs to reach).

[0076] The second position detection element is located between the first position detection element and the fourth position detection element, and is used to mark the acceleration position when the material platform 620 rises or the deceleration position when it falls; the third position detection element is located between the second position detection element and the fourth position detection element, and is used to mark the deceleration position when the material platform 620 rises or the acceleration position when it falls.

[0077] The first, second, third, and fourth position detection elements can be non-contact detection devices such as proximity switches, photoelectric sensors, or magnetic sensors, or they can be Hall effect sensors or infrared sensors. The electrically controlled directional valve assembly 500 is electrically connected to the first, second, third, and fourth position detection elements via wires, receives their trigger signals, and controls the operating status of the material lifting hydraulic motor 440.

[0078] In another optional embodiment, the first position detection element, the second position detection element, the third position detection element and the fourth position detection element can be replaced with mechanical limit switches or ultrasonic ranging modules, and their installation positions are dynamically adjusted according to the length of the ladder arm 610 (e.g., the second position detection element of a 10-meter ladder arm 610 is set at 3 meters from the bottom).

[0079] When the operator activates the one-button lifting function of the material platform 620, the electrically controlled directional valve assembly 500 automatically adjusts the speed of the material lifting hydraulic motor 440 according to the signals from the various position detection devices, taking the lifting of the material platform 620 as an example.

[0080] Initial position trigger: The material platform 620 starts from the first position detection piece (bottom end) and runs at a low speed (e.g., 0.1m / s).

[0081] Acceleration position trigger: When the platform reaches the second position detection element (5 meters high), the proportional directional valve 520 reduces the flow rate and the rotation speed increases to full speed (e.g., 0.5 m / s).

[0082] Deceleration position trigger: When the platform reaches the third position detection piece (height 12 meters), the proportional directional valve 520 gradually increases the flow rate, and the speed drops to a low speed (e.g., 0.1 m / s). Target position trigger: When the platform reaches the fourth position detection piece (height 15 meters), the first electronically controlled directional valve 510 cuts off the oil circuit, and the platform stops running.

[0083] During descent, the position detection devices function in reverse: the third position detection device triggers acceleration (high-speed descent), and the second position detection device triggers deceleration (low-speed descent). If other valve stems are manually operated (such as the luffing cylinder 410), the bridge passage immediately closes, the electronic control oil circuit is interrupted, and the one-button lifting function is forcibly terminated.

[0084] It is understood that in the towing ladder truck provided in this embodiment of the present invention, the automatic speed control of the material platform 620 throughout the entire lifting process is achieved through the coordinated action of four position detection devices on the ladder arm 610. Compared with the traditional solution that relies on manual experience to adjust the speed, this embodiment of the present invention improves operating efficiency during the acceleration phase and avoids material swaying or equipment impact caused by sudden stops during the deceleration phase, effectively improving operational stability and safety. This design significantly reduces operational complexity in high-rise building construction scenarios while optimizing energy utilization.

[0085] Continue reading Figure 1 In an optional embodiment of this utility model, the hydraulic circuit containing the track telescopic hydraulic motor 430 further includes a check valve 431 and a balance valve 432. The inlet of the check valve 431 is connected to the second end of the track telescopic hydraulic motor 430 (e.g., the return oil side of the motor), and the outlet is connected to the first end of the motor (e.g., the inlet oil side of the motor). The pressure port of the balance valve 432 is connected to the manual directional valve assembly 300, the return oil port of the balance valve 432 is connected to the first end of the track telescopic hydraulic motor 430, and the outlet of the check valve 431 is connected to the return oil port of the balance valve 432. The pilot control port of the balance valve 432 is connected to the second end of the track telescopic hydraulic motor 430.

[0086] In practical implementation, the check valve 431 can adopt a ball-type or cone-type structure. Its function is to allow hydraulic oil to flow unidirectionally from the second end of the motor to the first end, preventing reverse flow. The balance valve 432 is a hydraulically controlled valve, internally integrating the check valve 431 and the throttle valve core, such as using an FD-type balance valve or a cartridge-type balance valve module. Optionally, the check valve 431 can be replaced with a hydraulically controlled check valve, whose opening and closing are controlled by an external oil circuit; the balance valve 432 can also adopt a split design (such as an independent check valve + relief valve combination) to adapt to different installation space requirements.

[0087] During the extension process of ladder arm 610: After the manual reversing valve assembly 300 pushes the valve stem, high-pressure oil enters the first end of the track telescopic hydraulic motor 430 through the pressure oil port of the manual reversing valve assembly 300 and the balance valve 432, driving the track telescopic hydraulic motor 430 to rotate (for example, winding up the wire rope to extend ladder arm 610). At this time, the low-pressure oil at the second end of the track telescopic hydraulic motor 430 flows back to the oil tank 200 through the manual reversing valve assembly 300, forming a circulating oil circuit.

[0088] During the retraction process of ladder arm 610: When the valve stem of the manual reversing valve assembly 300 is operated in reverse, high-pressure oil enters the second end of the track telescopic hydraulic motor 430 through the manual reversing valve assembly 300. At the same time, high-pressure oil flows towards the side where the first end of the track telescopic hydraulic motor 430 is located through the one-way valve 431. In other words, during this process, the track telescopic hydraulic motor 430 and the one-way valve 431 are in parallel. Due to the presence of the one-way valve 431, the pressure of the hydraulic oil at the first and second ends of the track telescopic hydraulic motor 430 is balanced. The rotor of the track telescopic hydraulic motor 430 is in a floating state. Under the action of its own weight, each section of ladder arm 610 gradually descends and retracts.

[0089] During this process, high-pressure oil enters the balance valve 432 from the pilot control port, pushing the valve core of the balance valve 432 to adjust the opening of the return port. Under the action of high-pressure oil, a preset back pressure is provided, so that the ladder arm 610 descends and retracts at a predetermined speed based on the preset back pressure, thereby preventing stalling and falling during retraction. If the load on the ladder arm 610 changes suddenly (such as jamming), the balance valve 432 limits the system pressure through its internal overflow function to protect the hydraulic components.

[0090] It is understood that in the towing ladder truck provided in this embodiment of the present invention, the problem of stalling or impact caused by the self-weight during the extension and retraction of the ladder arm 610 is solved through the synergistic action of the one-way valve 431 and the balance valve 432. The pilot control mechanism of the balance valve 432 can dynamically adjust the return oil resistance according to the load to ensure that the ladder arm 610 descends and retracts at a uniform speed, which can avoid structural vibration or wire rope loosening caused by sudden stops and starts; the one-way valve 431 optimizes the oil circuit circulation efficiency and reduces energy loss.

[0091] In existing towing ladder trucks, there is a structure in which a material lifting hydraulic motor 440 and a material lifting hydraulic motor 440 work together. Specifically, the hydraulic circuit of the material lifting hydraulic motor 440 is also equipped with a corresponding check valve and a balance valve. The arrangement of the check valve and balance valve in this circuit is the same as that in the circuit of the track telescopic hydraulic motor 430, and the working principle is similar. For details, please refer to the description of the check valve 431 and balance valve 432 in the circuit of the track telescopic hydraulic motor 430.

[0092] Furthermore, to enable collaborative functionality, the system also connects the first end of the material lifting hydraulic motor 440 and the second end of the track telescopic hydraulic motor 430 via a collaborative pipeline, and the second end of the material lifting hydraulic motor 440 and the first end of the track telescopic hydraulic motor 430 are also connected via a collaborative pipeline. The system also includes two check valves, each located on the collaborative pipeline. The inlets of both check valves face the track telescopic hydraulic motor 430, and the outlets of both check valves face the material lifting hydraulic motor 440. This means that the two check valves allow hydraulic oil from the circuit containing the track telescopic hydraulic motor 430 to enter the circuit containing the material lifting hydraulic motor 440, while preventing hydraulic oil from entering the circuit containing the material lifting hydraulic motor 440 from entering the circuit containing the track telescopic hydraulic motor 430.

[0093] Accordingly, during the extension of the ladder arm 610, the material platform 620 will slowly descend, so that the material platform 620 will not affect the ladder extension action as the ladder arm 610 rises to a higher position; during the descent of the ladder arm 610, the material platform 620 will slowly rise, so that the material platform 620 will not cause the winch rope to become tangled after falling to the ground as the ladder arm 610 retracts.

[0094] However, this collaborative structure has a drawback. During use, due to inconsistent actual angles of the ladder arm 610 (e.g., 30°, 50°, or 80°), changes in hydraulic oil viscosity, and other influencing factors, the movement speed of the ladder arm 610 and the material platform 620 may become inconsistent. For example, during the ascent, ideally, the ladder arm 610 should rise while the material platform 620 descends, keeping the material platform 620 relatively stationary in space. However, the aforementioned factors may cause the speed of the material platform 620 to increase or decrease, disrupting its intended relatively stationary state. Similarly, during the descent, ideally, the ladder arm 610 should descend while the material platform 620 rises, keeping it relatively stationary in space. However, the aforementioned factors may cause the speed of the material platform 620 to increase or decrease, disrupting its intended relatively stationary state.

[0095] The speeds of the material platform 620 and the ladder arm 610 are often inconsistent. Therefore, during use, the balance valve 432 in the circuit where the track telescopic hydraulic motor 430 is located is dynamically adjusted for active control. For example, the preset pressure in the balance valve 432 is changed or reduced to change the speed at which the ladder arm 610 rises or falls.

[0096] After adjusting the balance valve 432 in the circuit containing the track telescopic hydraulic motor 430, the change often results in the preset pressure of the balance valve 432 being different from the circuit pressure required when the ladder arm 610 descends by its own weight. In other words, the adjusted preset pressure is different from the initial preset pressure. This may cause the track telescopic hydraulic motor 430 to continue to reverse after the ladder arm 610 has fallen to the bottom, leading to the winch rope tangling problem, or the track telescopic hydraulic motor 430 may start to rotate forward.

[0097] Regarding the issue of the balance valve 432 in the circuit containing the track telescopic hydraulic motor 430, in an optional embodiment of this utility model, the electrically controlled directional valve assembly 500 further includes a second electrically controlled directional valve 530 and a third electrically controlled directional valve 540. One end of the second electrically controlled directional valve 530 is connected to the oil tank 200, and the other end is connected to the pressure port of the balance valve 432. One end of the third electrically controlled directional valve 540 is connected to the oil tank 200, and the other end is connected to the oil inlet of the check valve 431 (i.e., the oil circuit corresponding to the second end of the track telescopic hydraulic motor 430). The second electrically controlled directional valve 530 and the third electrically controlled directional valve 540 can be selected as two-position two-way solenoid valves or proportional solenoid valves, and their opening and closing states are controlled by electrical signals. It should be noted that the second electrically controlled directional valve 530 and the third electrically controlled directional valve 540 can also adopt a cartridge structure and be integrated inside the valve block to save space.

[0098] During the normal extension of the ladder arm 610, when the manual reversing valve assembly 300 drives the track telescopic hydraulic motor 430, high-pressure hydraulic oil flows from the first end to the second end of the track telescopic hydraulic motor 430. At this time, the second electrically controlled reversing valve 530 and the third electrically controlled reversing valve 540 are in a normally closed state, which does not affect the operation of the system.

[0099] When the boom 610 touches the top, the second electrically controlled reversing valve 530 opens, releasing the high-pressure oil on the pressure port side of the balance valve 432 (the side where the first end of the drive track telescopic hydraulic motor 430 is located), so that the high-pressure oil no longer passes through the balance valve 432 and enters the track telescopic hydraulic motor 430. In this way, the track telescopic hydraulic motor 430 will not continue to rotate, so as to avoid the problem of the wire rope breaking due to the continued tension of the winch wire rope.

[0100] During the normal retraction of the ladder arm 610, when the manual reversing valve assembly 300 drives the track telescopic hydraulic motor 430, high-pressure hydraulic oil flows from the manual reversing valve assembly 300 to the large check valve 431, and then returns to the return port of the manual reversing valve assembly 300 through the check valve 431. During this process, the rotor of the track telescopic hydraulic motor 430 is in a floating state, and the ladder arm 610 descends under its own weight. The balance valve 432 controls the descending speed of the ladder arm 610. At this time, the second electrically controlled reversing valve 530 and the third electrically controlled reversing valve 540 are in a normally closed state, which does not affect the operation of the system.

[0101] After the ladder arm 610 touches the bottom, the third electrically controlled directional valve 540 opens, releasing the pressure on the oil inlet side of the check valve 431. This allows the high-pressure oil that originally entered the check valve 431 to be discharged directly to the oil tank 200 through the third electrically controlled directional valve 540, without passing through the return oil pipes of the check valve 431, balance valve 432, and manual directional valve assembly 300. At the same time, no hydraulic oil passes through the track telescopic hydraulic motor 430.

[0102] It is understood that in the towing ladder truck provided by this utility model embodiment, the pressure relief function of the second electrically controlled reversing valve 530 and the third electrically controlled reversing valve 540 solves the problem of loss of control caused by pressure mismatch when the ladder arm 610 touches the top or bottom. This utility model embodiment actively releases the pressure at key nodes at the moment when the ladder arm 610 touches the top or bottom, so that the hydraulic motor is locked, avoiding the risk of wire rope breakage, rope tangling or abnormal movement.

[0103] In an optional embodiment of this utility model, an upper limit device and a lower limit device are added to the traction ladder truck. The upper limit device (such as a mechanical limit switch or a proximity sensor) is fixed near the limit position where the ladder arm 610 is fully extended, and its signal output terminal is electrically connected to the control circuit of the second electrically controlled reversing valve 530.

[0104] When the ladder arm 610 extends to its limit position, the upper limit device is triggered (such as a stop block squeeze switch or a sensor sensing a metal mark), sending a conduction signal to the second electronically controlled directional valve 530, connecting the manual directional valve assembly 300 and the oil tank 200 oil circuit.

[0105] Similarly, the lower limit switch is installed at the fully retracted extreme position of the ladder arm 610. Its signal output terminal is electrically connected to the control circuit of the third electrically controlled directional valve 540. When the ladder arm 610 retracts to the extreme position, the lower limit switch is triggered, controlling the third electrically controlled directional valve 540 to connect the manual directional valve assembly 300 and the oil tank 200. The upper and lower limit switches can be selected from Hall sensors, mechanical lever limit switches, or ultrasonic ranging modules, etc., according to the actual situation.

[0106] It is understood that in the traction ladder truck provided by this utility model embodiment, automatic locking protection of the ladder arm 610 at its telescopic limit position is achieved through the linkage of the upper and lower limit components with the second and third electrically controlled directional valves 530 and 540. Regarding the pressure mismatch problem caused by adjusting the balance valve 432 (such as rope tangling upon bottoming out), this utility model embodiment actively releases the pressure at key nodes when the ladder arm 610 reaches its limit position, causing the track telescopic hydraulic motor 430 to lock in response, maintaining system stability without manual intervention.

[0107] It should be noted that the technical solutions in the various embodiments of this utility model can be combined with each other, but the basis for such combination is that they can be implemented by those skilled in the art. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist, that is, it is not within the protection scope of this utility model.

[0108] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model 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 of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A hydraulic control system, characterized in that, include: Power components are used to supply hydraulic fluid; A manual directional valve assembly is connected downstream of the power assembly, and the downstream of the manual directional valve assembly is connected to the oil tank. The manual directional valve assembly includes a first state, a second state, and a third state. An actuator, connected downstream of the manual directional valve assembly, is used to convert hydraulic energy into mechanical energy for output; An electrically controlled directional valve assembly is connected to the oil tank; in a first state, the manual directional valve assembly is in forward communication with the actuation component, and the manual directional valve assembly is disconnected from the electrically controlled directional valve assembly; in a second state, the manual directional valve assembly is in reverse communication with the actuation component, and the manual directional valve assembly is disconnected from the electrically controlled directional valve assembly; in a third state, the manual directional valve assembly is disconnected from the actuation component, and the manual directional valve assembly is connected to the electrically controlled directional valve assembly.

2. The hydraulic control system according to claim 1, characterized in that, The electronically controlled directional valve assembly includes: A first electrically controlled directional valve is connected between the manual directional valve assembly and the actuation assembly; A proportional directional valve is connected between the manual directional valve assembly and the oil tank. The proportional directional valve is used to control the flow rate of hydraulic oil in the first electrically controlled directional valve.

3. The hydraulic control system according to claim 2, characterized in that, The electrically controlled directional valve assembly also includes a valve body, the valve body being provided with a mounting portion; The first electrically controlled directional valve is detachably inserted into the mounting portion, and / or the proportional directional valve is detachably inserted into the mounting portion.

4. The hydraulic control system according to claim 1, characterized in that, The manual directional valve assembly includes multiple six-way valves, each of which is provided with an actuation position and a manual / electric switching position. The actuation position of each six-way valve is respectively connected to the actuation assembly. The manual switching positions of all the six-way valves are connected in series, and the manual switching position of each six-way valve can independently disconnect the connection between the electric directional valve assembly and the power assembly.

5. The hydraulic control system according to claim 4, characterized in that, The execution component includes multiple execution parts, each of which includes a hydraulic cylinder or a hydraulic motor; Multiple actuators are connected to multiple six-way valves in a one-to-one correspondence, and at least one pair of the multiple pairs of actuators and six-way valves are connected to the electrically controlled directional valve assembly.

6. A towed aerial ladder truck, characterized in that, Includes the vehicle body and the hydraulic control system as described in any one of claims 1 to 4; The execution component includes: A luffing cylinder is connected to the manual directional valve assembly. The luffing cylinder is used to control the angle between the ladder arm of the vehicle body and the ground. A rotary hydraulic motor is connected to the manual directional valve assembly, and the rotary hydraulic motor is used to control the rotation angle of the ladder arm of the vehicle body; A track telescopic hydraulic motor is connected to the manual reversing valve assembly, and the track telescopic hydraulic motor is used to control the extension and retraction of the ladder arm of the vehicle body; The material lifting hydraulic motor is connected to the manual reversing valve assembly and the electronically controlled reversing valve assembly. The material lifting hydraulic motor is used to control the raising or lowering of the material platform of the vehicle body.

7. The towed aerial ladder truck according to claim 6, characterized in that, The ladder arm is provided with a first position detection element, a second position detection element, a third position detection element, and a fourth position detection element at intervals along its length; the electrically controlled reversing valve assembly is electrically connected to the first position detection element, the second position detection element, the third position detection element, and the fourth position detection element respectively; The first position detection device is used to determine the initial position of the material platform; the second position detection device is used to determine the rising acceleration position or the falling deceleration position of the material platform; the third position detection device is used to determine the rising deceleration position or the falling acceleration position of the material platform; and the fourth position detection device is used to determine the preset target position of the material platform.

8. The towed aerial ladder truck according to claim 6, characterized in that, Also includes: A one-way valve, wherein the oil outlet of the one-way valve is connected to the first end of the track telescopic hydraulic motor, and the oil inlet of the one-way valve is connected to the second end of the track telescopic hydraulic motor; The balance valve has its pressure port connected to the manual directional valve assembly, its return port connected to the first end of the track telescopic hydraulic motor, and the outlet port of the check valve connected to the return port of the balance valve. The pilot control port of the balance valve is connected to the second end of the telescopic hydraulic motor.

9. The towed aerial ladder truck according to claim 8, characterized in that, The electronically controlled directional valve assembly also includes: The second electrically controlled directional valve is connected at one end to the oil tank and at the other end to the pressure oil port of the balance valve; The third electrically controlled directional valve is connected at one end to the oil tank and at the other end to the oil inlet of the check valve.

10. The towed aerial ladder truck according to claim 9, characterized in that, Also includes: An upper limit switch is electrically connected to the second electrically controlled directional valve. The upper limit switch is used to determine the extension limit position of the ladder arm. When the upper limit switch is triggered, the second electrically controlled directional valve connects the manual directional valve assembly and the oil tank. The lower limit component is electrically connected to the third electrically controlled directional valve. The lower limit component is used to determine the shortening limit position of the ladder arm. When the lower limit component is triggered, the third electrically controlled directional valve connects the manual directional valve assembly and the oil tank.

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