Adaptive near-bore valve block assembly based on hydraulic potential energy recovery and control method thereof

Abstract

This invention discloses an adaptive proximity valve block assembly and its control method based on hydraulic potential energy recovery. The valve block assembly is fixedly connected to a hydraulic cylinder. The valve block internally includes a balance and stabilization passage, a pre-charge buffer passage, a flow-limiting access passage, a main recovery passage, and a buffer chamber. The pre-charge buffer passage has a one-way throttling element and connects to the buffer chamber. The flow-limiting access passage has a fixed throttling orifice connecting the buffer chamber and an energy storage unit. The main recovery passage has a hydraulically controlled directional valve driven by the pressure difference between the buffer chamber and the energy storage unit. After recovery is enabled, the high-pressure return oil preferentially enters the buffer chamber to absorb the first wave of pressure redistribution due to the fast-forward characteristic of the one-way throttling element. Then, it slowly releases the second wave of impact by charging the energy storage unit at a low flow rate through the fixed throttling orifice. After the pressure difference shrinks to a threshold, the hydraulically controlled directional valve automatically opens the main recovery passage. This invention reconstructs the recovery entry from a one-step opening to a hydraulically automatic graded access sequence, significantly suppressing entry pulsation, avoiding main control misjudgment, and improving execution stability.

Description

Technical Field

[0001] This invention relates to the field of industrial hydraulic actuation and energy-saving control technology, specifically to a hydraulic cylinder assembly and its energy recovery control system for heavy-duty equipment such as vertical lifting, pressing, tilting, and logistics lifting. Background Technology

[0002] In equipment such as construction machinery, hydraulic elevators, and heavy-duty presses, utilizing the gravitational potential energy during load descent or braking is an important way to reduce system power consumption and energy consumption. The conventional technical objective is to, while ensuring the stability and safety of the actuator's movement, channel the high-pressure oil discharged from the rodless chamber of the hydraulic cylinder during load descent into an energy storage unit (such as an accumulator) for storage, and release it during the lifting phase to assist the main pump in supplying oil, thereby achieving energy savings.

[0003] To achieve the above objectives, early solutions often used independent valve assemblies and pipelines to connect the hydraulic cylinder and the accumulator, such as switching the return oil line to the accumulator charging circuit by adding a solenoid directional valve. To further improve integration and reduce pipeline losses, CN201843849U discloses a hydraulic cylinder with an accumulator. The accumulator is fixed to the outer wall of the cylinder barrel by a bracket and connected to the cylinder oil port through a four-way valve block, achieving a near-cylinder integrated arrangement of the accumulator and hydraulic cylinder. This structural improvement effectively shortens the energy transmission path and reduces pressure loss along the stroke.

[0004] CN101435451B further discloses a method and device for recovering potential energy from an excavator boom. This method uses a third solenoid valve to directly connect the rodless chamber to an accumulator for energy recovery, and a proportional valve to regulate the flow rate when the accumulator releases stored energy to drive a generator, thereby suppressing pressure fluctuations during the energy release phase. CN216518936U introduces a balance valve, a hydraulically controlled directional valve, and a shuttle valve into the hydraulic motor balance valve group, achieving both motor braking energy recovery and safe release under abnormal pressure differences between the two chambers.

[0005] While the aforementioned solutions have made progress in improving energy recovery efficiency and system integration, the applicant discovered a hidden problem during actual engineering verification that was not revealed by existing technologies: When the recovery channel switches from a closed to a conducting state, the impedance of the return oil path changes abruptly, causing transient pressure redistribution in the near-cylinder region—the limited volume space between the rodless chamber outlet and the valve block sampling port. This pressure redistribution, after being fed back to the main controller via pressure sampling, is easily misinterpreted by the main control algorithm as a sudden load change, triggering a secondary correction action of the main control valve. This manifests as speed fluctuations or even unexpected downward surges in the actuator cylinder during recovery engagement. The proportional valve in CN101435451B only regulates the accumulator's energy release phase, not the near-cylinder pulsation at the moment of recovery engagement; the safety release function in CN216518936U also only addresses abnormal pressure differences between the two chambers of the motor and is unrelated to the transient control during the recovery engagement process.

[0006] Therefore, in the near-cylinder integrated configuration, how to suppress the interference of near-cylinder pressure pulsation at the moment of recovery engagement on the main control circuit has become a technical problem that urgently needs to be solved but has not yet been addressed in this field, and there is a real need to improve this problem. Summary of the Invention

[0007] To address the problem in existing technologies that fail to address the interference caused by near-cylinder pressure pulsation during the recovery cut-in moment to the main control circuit, this invention provides an adaptive near-cylinder valve block assembly based on hydraulic potential energy recovery and its control method. By suppressing the cut-in pulsation through hydraulic automatic graded access sequence, energy recovery and execution stability are coordinated.

[0008] The solution to the technical problem of this invention is as follows: An adaptive proximity valve block assembly based on hydraulic potential energy recovery is used, fixedly connected to a hydraulic cylinder, comprising: a proximity integrated valve block, an energy storage unit connected to the proximity integrated valve block, and a controller; the proximity integrated valve block internally forms: a balance and load stabilization passage, establishing a basic back pressure when the hydraulic cylinder descends; a pre-charge buffer passage, which contains a one-way throttling element and connects to a buffer chamber; a flow-limiting access passage, which contains a fixed throttling orifice, connecting the buffer chamber and the energy storage unit; and a main recovery passage, whose... A hydraulically controlled directional valve is provided, and the switching of the hydraulically controlled directional valve is triggered by the difference between the pressure in the buffer chamber and the pressure in the energy storage unit. After the controller outputs a recovery enable signal, the high-pressure return oil automatically enters the buffer chamber first due to the fast-forward characteristic of the one-way throttling element, and then fills the energy storage unit with a low flow rate through the fixed throttling orifice. When the difference between the pressure in the buffer chamber and the pressure in the energy storage unit decreases to a preset threshold, the hydraulically controlled directional valve automatically switches to conduct the main recovery path, thereby forming a hydraulic automatic graded access sequence that does not depend on the timing command of the controller.

[0009] Preferably, the one-way throttling element is a parallel combination of a one-way valve and a throttling orifice, or an integrated one-way throttling valve; the flow area of ​​the fixed throttling orifice does not exceed 1 / 10 of the flow area of ​​the main recovery passage; the volume of the buffer chamber is set according to 1 / 20 to 1 / 5 of the maximum instantaneous displacement of the rodless chamber of the hydraulic cylinder.

[0010] Preferably, the hydraulic control directional valve is a two-position two-way hydraulic control directional valve, with its first control port connected to the buffer chamber and its second control port connected to the energy storage unit; when the pressure difference between the first control port and the second control port is less than 0.2MPa to 0.5MPa, the hydraulic control directional valve automatically switches to the on position.

[0011] Preferably, the near-cylinder integrated valve block has a rodless chamber pressure sampling port and a rod chamber pressure sampling port, and the flow path length between the sampling port and the corresponding chamber hydraulic channel does not exceed 50mm; the controller confirms that the system has entered a stable recovery state before the main recovery path is turned on based on the near-cylinder dual-chamber pressure signal obtained by the sampling port.

[0012] Preferably, the conditions for the controller to confirm that the system has entered a stable recovery state include: the absolute value of the pressure change rate in the rodless chamber is less than a first threshold, the absolute value of the pressure change rate in the rod chamber is less than a second threshold, and the fluctuation rate of the piston displacement speed is less than a third threshold.

[0013] Preferably, the cylinder-integrated valve block is further provided with a safety cut-off passage, which includes a power-off type two-position two-way solenoid valve; when the two-position two-way solenoid valve is de-energized, the connection between the inlet of the main recovery passage and the pre-charge buffer passage and the hydraulic cylinder chamber is cut off, and the system reverts to a safe state in which only the balance and load-stabilizing passage is kept in operation.

[0014] Preferably, the near-cylinder integrated valve block is further provided with an energy release booster passage, which replenishes the pressure oil stored in the energy storage unit to the main oil supply passage through a one-way valve during the lifting stage of the hydraulic cylinder; the energy release booster passage shares the same near-cylinder integrated valve block with the pre-charge buffer passage and the main recovery passage, but is isolated by the one-way valve.

[0015] Preferably, the controller is further configured to: in the main recovery path being open, determine whether to maintain the main recovery path being open based on a comparison between the estimated recovery revenue and the estimated additional throttling loss; the estimated additional throttling loss includes the pressure drop loss generated by the fixed throttling orifice during the current limiting access phase.

[0016] A control method for an adaptive cylinder proximity valve assembly based on hydraulic potential energy recovery, wherein the adaptive cylinder proximity valve assembly is the adaptive cylinder proximity valve assembly according to any one of claims 1 to 8, comprising the following steps: S1. In the case of hydraulic cylinder downward movement or deceleration, the balance and load stabilization passage is kept in working state to establish a stable load back pressure; S2. When the recovery condition is detected, the controller outputs a recovery enable signal to open the pre-charge buffer passage, allowing high-pressure return oil to enter the buffer chamber through the one-way throttling element to absorb the first wave of pressure redistribution at the moment of recovery entry; S3. The pressure oil in the buffer chamber is filled to the energy storage unit at a low flow rate through the fixed throttling orifice to mitigate the second wave of flow impact; S4. The pressure change rate and piston displacement speed of the cylinder dual chamber are monitored. When the absolute value of the pressure change rate is less than the corresponding threshold and the displacement speed fluctuation rate is less than the preset value, the main recovery passage is opened; S5. In the state where the main recovery passage is open, a decision is made on whether to maintain the main recovery mode based on the comparison result between the estimated recovery benefit value and the estimated additional throttling loss value.

[0017] The beneficial effects of this invention are as follows: 1. By constructing a hydraulic automatic graded access sequence consisting of a pre-charge buffer path, a current-limiting access path, and a main recovery path, the traditional "one-step" recovery entry is reconstructed into a progressive process of "pre-absorption in the buffer chamber → slow release from the fixed throttling orifice → delayed opening of the main path." This effectively suppresses recovery entry pulsations, avoids secondary corrections in the main control loop due to pulsation misjudgment, and significantly improves the execution stability under heavy-load vertical conditions.

[0018] 2. The tiered access sequence is automatically achieved through the rapid-advance characteristics of the unidirectional throttling element, the flow-limiting effect of the fixed throttling orifice, and the differential pressure drive of the hydraulically controlled directional valve, without relying on the precision of the controller's timing commands. This hydraulic logic network hardware-izes the tiered process, avoiding the complex work of adapting software parameters to different operating conditions, and reducing the difficulty of debugging and maintenance costs of the control system. Furthermore, this solution is still based on standard hydraulic valves, valve blocks, accumulators, and sensors, without introducing new components beyond current industrial manufacturing capabilities, thus possessing good engineering feasibility and economic efficiency.

[0019] 3. The load balancing and stabilizing path always has the highest priority, and the hardware priority design of the safety disconnection path ensures that the system can quickly revert to a safe state with only basic back pressure under any abnormal operating conditions. This load-priority and safety-backup architecture enables the invention to operate reliably in situations with stringent safety and stability requirements, such as heavy-load vertical lifting, mine hoisting, and large-scale pressing operations with drastic load changes and frequent external disturbances, verifying the robustness of the solution. Meanwhile, the integrated design of the shared valve block for the energy release and recovery paths provides a reliable foundation for the iterative development of subsequent multi-actuator collaborative energy saving and intelligent energy management strategies. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the hydraulic system according to the first embodiment of the present invention.

[0021] Figure 2 yes Figure 1 A cross-sectional schematic diagram of the internal flow path structure of the integrated valve block for the intermediate cylinder.

[0022] Figure 3 It is a timing diagram of the conduction status of each path during the recycling and access process.

[0023] Figure 4 It is a control logic flowchart.

[0024] Figure 5 This is a comparison chart of the rodless chamber pressure sampling curves at the moment of retraction cut-in between the comparative method and the method of this embodiment.

[0025] Figure 6 This is a schematic diagram of the circuit principle. Detailed Implementation

[0026] During actual engineering verification, the applicant discovered that when the recovery channel switches from a closed to a connected state, a sudden change in the impedance of the return oil path occurs, leading to a transient pressure redistribution in the limited volume space near the cylinder (i.e., between the rodless chamber outlet and the valve block sampling port). This pressure redistribution, after being fed back to the main controller via pressure sampling, is easily misinterpreted by the main control algorithm as a sudden load change, triggering a secondary correction action of the main control valve. This manifests as speed fluctuations or even unexpected downward thrusts in the actuator cylinder during recovery engagement. Therefore, the technical problem this embodiment aims to solve is: in a near-cylinder integrated valve block configuration, the near-cylinder pressure pulsation caused by the sudden change in return oil path impedance during the switching of the hydraulic potential energy recovery channel from closed to connected interferes with the main control circuit, resulting in decreased actuator cylinder speed stability. This is not simply about improving recovery efficiency.

[0027] Example 1: Refer to Figure 1 and Figure 2 This embodiment provides an adaptive proximity valve block assembly based on hydraulic potential energy recovery, which is fixedly connected to a hydraulic cylinder 100. The hydraulic cylinder 100 is a single-piston rod double-acting cylinder, including a rodless chamber A and a rod chamber B, with the piston rod connected to a load platform (not shown in the figure). The proximity integrated valve block 200 is bolted to the rear end cover 15 or cylinder seat of the hydraulic cylinder 100. Several hydraulic flow channels and chambers are formed inside the valve block 200 through drilling or casting. The energy storage unit 300 is connected via a pipeline to the energy storage interface Pacc of the valve block 200. The controller 400 is a programmable logic controller or an embedded industrial controller, receiving signals from a pressure sensor and a displacement sensor 13 (on the hydraulic cylinder 100, used to measure piston displacement), and outputting solenoid valve control signals.

[0028] The cylinder-integrated valve block 200 has at least the following functional passages (flow paths) internally, as shown in the reference. Figure 1 and Figure 2 1. Main oil supply passage L1: connects the hydraulic source P (such as the outlet of a variable pump or proportional directional valve 14) to the rodless chamber A and rod chamber B of the hydraulic cylinder 100, and is used for oil inlet and outlet under normal working conditions. The normal working conditions are the existing conventional common method.

[0029] 2. Balanced load stabilizing passage L2: This includes a one-way back pressure valve 3, whose inlet is connected to the rodless chamber A and whose outlet is connected to the return port T. The set opening pressure of this one-way back pressure valve 3 is 5 MPa. When the hydraulic cylinder 100 moves downward under load, the oil discharged from the rodless chamber A must overcome this back pressure to flow back to the oil tank, thereby ensuring that the rodless chamber A maintains a basic back pressure of not less than 5 MPa at all times, preventing piston stall and downward thrust due to sudden changes in external load. The conduction of this balanced load stabilizing passage L2 depends only on whether the pressure in the rodless chamber A exceeds the set value, and is unrelated to whether the recovery function is activated.

[0030] 3. Pre-charge buffer passage L3: This includes an inlet control valve 4 and a one-way throttling element 5, with the outlet connected to a buffer chamber Vbuff (labeled 16). The inlet control valve 4 is a two-position, normally closed solenoid valve that opens the pre-charge buffer passage L3 when energized. The one-way throttling element 5 consists of a one-way valve and a throttling orifice connected in parallel. Its forward flow resistance (flow from the inlet control valve 4 to the buffer chamber Vbuff) is significantly less than its reverse flow resistance. The buffer chamber Vbuff is a cavity directly machined inside the valve block 200, with a volume of approximately 50 mL.

[0031] 4. Current-limiting access path L4: Connects the buffer chamber Vbuff and the energy storage interface Pacc. A fixed throttling orifice 6 is provided on this path. The flow diameter of the fixed throttling orifice 6 is designed to be φ1.2mm. Alternatively, a micro-filter can be added to the front end of this current-limiting access path, or the throttling orifice can be surface-hardened to ensure the long-term stability of this key throttling parameter.

[0032] 5. Main recovery passage L5: Connected in parallel with pre-charge buffer passage L3, and equipped with a hydraulically controlled directional valve 7. The hydraulically controlled directional valve 7 is a two-position two-way hydraulically controlled valve, with its first control port K1 connected to the buffer chamber Vbuff and its second control port K2 connected to the energy storage interface Pacc. When the pressure difference between K1 and K2 is less than a preset threshold (set to 0.3MPa in this embodiment), the hydraulically controlled directional valve 7 automatically switches to the open position; otherwise, it remains closed.

[0033] 6. Energy release booster passage L6: includes a one-way valve 8 and a two-position two-way solenoid valve 9, connecting the energy storage interface Pacc with the main oil supply passage L1. The one-way valve 8 is directed from the energy storage interface Pacc to the main oil supply passage L1 to prevent high-pressure oil from the main pump from flowing back into the accumulator.

[0034] 7. Safety cut-off path L7: This includes a power-off type two-position two-way solenoid valve 10 (normally closed valve), located between the common inlet of the pre-charge buffer path L3, the main recovery path L5, and the energy release boost path L6 and the rodless chamber A. When the solenoid valve 10 is de-energized, the connection between the above three paths and the rodless chamber A is cut off, and the system retains only the balance and stabilization path L2 for operation.

[0035] The near-cylinder integrated valve block 200 has a rodless chamber pressure sampling port 201 and a rod chamber pressure sampling port 202, which are used to install the rodless chamber pressure sensor 11 (the sampling port 201 is specially opened on the near-cylinder integrated valve block 200, and the flow channel length between this sampling port 201 and the outlet of the rodless chamber A hydraulic channel is 35mm) and the rod chamber pressure sensor 12 (the sampling port 202 is specially opened on the near-cylinder integrated valve block 200, and the flow channel length between this sampling port 202 and the outlet of the rod chamber B hydraulic channel is 28mm). The flow channel length between sampling port 201 and the outlet of the rodless chamber A hydraulic channel is designed to be 35mm, and the flow channel length between sampling port 202 and the outlet of the rod chamber B hydraulic channel is 28mm. This short flow channel design avoids the pressure signal filtering delay effect caused by long pipelines, ensuring that the controller 400 obtains the true transient pressure in the near-cylinder region.

[0036] The following combination Figures 1 to 4 The working process of this embodiment is explained.

[0037] Step S1: Establish stable back pressure. When the hydraulic cylinder 100 moves downward under load, regardless of whether the recovery function is enabled, the oil discharged from the rodless chamber A must flow back to the oil tank through the one-way back pressure valve 3 of the balance and stable load passage L2. Thus, a basic back pressure of 5MPa is automatically established in the rodless chamber A to provide the minimum safe support force for the piston.

[0038] Step S2: The pre-charge buffer path is activated, and the controller 400 acquires signals from the rodless chamber pressure sensor 11, the rod chamber pressure sensor 12, and the displacement sensor (not shown in the figure) in real time. When the following conditions are simultaneously met, the system is determined to have entered the recyclable operating condition:

[0039] The rodless chamber pressure P1 is higher than the energy storage unit pressure Pacc by a preset difference (2 MPa in this embodiment).

[0040] The direction of the piston displacement velocity v is the same as the load direction (downward), and the velocity value is greater than a minimum threshold.

[0041] Once the conditions are met, the controller 400 outputs a recovery enable signal, energizing and opening the inlet control valve 4 of the pre-charge buffer passage L3. Due to the forward rapid-advance characteristic of the one-way throttling element 5, the high-pressure oil discharged from the rodless chamber A preferentially enters the buffer chamber Vbuff quickly with lower resistance. During this process, the first pressure redistribution caused by the sudden opening of the recovery channel is absorbed by the volume effect of the buffer chamber Vbuff, and the pressure pulsation amplitude at the near-cylinder pressure sampling port 201 is suppressed.

[0042] Step S3: After the pressure inside the buffer chamber Vbuff is established, the oil in the chamber is pumped into the energy storage unit 300 through the fixed throttling orifice 6 of the flow-limiting access passage L4. Due to the small flow area of ​​the fixed throttling orifice 6 (φ1.2mm), the pumping process is a slow-release process with low flow rate and low impact, significantly weakening the second flow impact caused by the transition from the buffer chamber Vbuff to the energy storage unit 300. This stage provides a time window for the system to identify transient stability.

[0043] Step S4: The main recovery path is activated. During the flow-limiting connection process, the pressure PK1 in the buffer chamber Vbuff gradually approaches the pressure PK2 in the energy storage unit 300. When the difference between the two, ΔP = PK1 - PK2, decreases to below 0.3 MPa, the hydraulic control directional valve 7 is directly driven by the pressure difference across its two ends and automatically switches to the activated position, activating the main recovery path L5. At this time, the high-pressure oil discharged from the rodless chamber A is charged into the energy storage unit 300 through the main recovery path L5 at the main flow rate (designed in this embodiment to reach 60 L / min), entering the normal energy recovery mode.

[0044] It should be noted that the activation of the main recovery path L5 in step S4 is automatically triggered by the hydraulic directional valve 7 based on the physical pressure difference, without relying on additional timing commands from the controller 400. This hierarchical sequence, automatically guaranteed by hydraulic logic elements, avoids the uncertainties in software control timing and the robustness issues of parameter tuning.

[0045] Step S5: Maintain or exit the decision. With the main recovery path L5 in the on state, the controller 400 continuously evaluates the recovery benefits and additional losses. Specifically, the controller 400 calculates the following parameters: estimated recovery benefit: the recovered energy estimated based on the integral of the flow rate and the product of the pressure when charging the energy storage unit 300; estimated additional throttling loss: including at least the pressure drop loss generated by the fixed throttling orifice 6 during the current limiting access phase.

[0046] When the estimated recovery benefit is greater than the estimated additional throttling loss, the main recovery path L5 remains open; otherwise, the controller 400 closes the inlet control valve 4, the hydraulic directional valve 7 is reset and closed due to the disappearance of the pressure difference between the two ends, the system exits the recovery mode and resumes the normal balanced load throttling control.

[0047] Step S6: Abnormal safety handling. In any operating phase, if the controller 400 detects any of the following abnormal situations, the solenoid valve 10 of the safety shut-off passage L7 will immediately lose power: any pressure sensor signal exceeds the range or is lost; the piston displacement signal is lost or a non-physical jump occurs; there is a significant mismatch between the sign / amplitude of the rodless chamber pressure change rate and the piston speed; the pressure of the energy storage unit 300 exceeds the safety limit.

[0048] After the solenoid valve 10 is de-energized, the connection between the pre-charge buffer passage L3, the main recovery passage L5, the energy release boost passage L6 and the rodless chamber A is cut off, and only the balance and load stabilization passage L2 remains in operation. The system returns to a safe state where the basic back pressure is provided by the one-way back pressure valve 3.

[0049] During the initial lifting phase of the hydraulic cylinder 100 or a sudden load increase, when the controller 400 detects that the pressure Pacc of the energy storage unit 300 is higher than the rodless chamber pressure P1 by a preset release threshold (e.g., 1 MPa), it energizes the solenoid valve 9 of the energy release boost passage L6. The pressurized oil stored in the energy storage unit 300 is replenished to the main oil supply passage L1 via the check valve 8, and together with the hydraulic source P, supplies oil to the rodless chamber A, reducing the peak flow demand of the hydraulic source. The energy release boost passage L6 and the recovery passage share the same near-cylinder integrated valve block 200, but are isolated by the check valve 8 to prevent backflow of high-pressure oil from the main pump.

[0050] The applicant compared the same vertical lifting platform with the following parameters: rated load of 3 tons, hydraulic cylinder diameter of 100mm, piston rod diameter of 70mm, stroke of 1200mm, hydraulic power source of constant pressure variable pump with rated pressure of 21MPa, and energy storage unit of bladder accumulator with nominal volume of 10L and pre-charged nitrogen pressure of 6MPa. Figure 1 The pre-charge buffer path L3 and the main recovery path L5 are merged into a single direct-flow path. This involves eliminating the buffer chamber Vbuff, the one-way throttling element 5, the fixed throttling orifice 6, and the hydraulically controlled directional valve 7, allowing the inlet control valve 4 to directly connect to the energy storage interface Pacc. When the platform load decreases and the recovery conditions are met, the inlet control valve 4 is directly activated. At the instant the inlet control valve 4 is activated, a pressure pulsation peak of approximately 8 MPa is recorded at the rodless chamber pressure sampling port 201. Simultaneously, the piston displacement sensor records an instantaneous speed fluctuation of approximately ±15% of the set speed. The main controller, detecting an abnormal pressure increase, misinterprets this as a sudden load increase and increases the opening of the proportional directional valve, causing significant downward jerking of the platform, which lasts for approximately 0.8 seconds before stabilizing.

[0051] Therefore, it can be seen that adopting Figure 1The complete hierarchical access structure shown was used for recovery switching under the same operating conditions. After the inlet control valve 4 was turned on, the buffer chamber Vbuff effectively absorbed the first wave of pressure redistribution. The pressure pulsation peak recorded at the rodless chamber pressure sampling port 201 was reduced to approximately 3.2 MPa, a decrease of about 60%. The piston speed fluctuation amplitude was reduced to within ±4%, and the platform descent was observed to be smooth with no obvious shaking. Throughout the entire transition process, the main controller did not trigger any unexpected proportional valve correction action due to pressure pulsation. Figure 5 As can be clearly observed from the curves, the pressure transition in this embodiment is smoother, and the pulsation amplitude is significantly reduced. The above comparison shows that this embodiment does not simply add a buffer chamber and a throttling element, but rather substantially solves the technical problem of the interference of recovery entry pulsation on the stability of the main control by constructing a hydraulic automatic graded access sequence from a pre-charge buffer path to a current-limiting access path to a main recovery path.

[0052] Example 2: Based on the first example, in order to further optimize the stability and recovery efficiency of the graded access process, the applicant provided a parameter matching relationship between the buffer cavity volume and the flow area of ​​the fixed throttling orifice.

[0053] There is a correlation between the volume V_buff of the buffer chamber and the maximum instantaneous displacement Q_max of the rodless chamber of the hydraulic cylinder 100. Experiments have verified that when V_buff is between Q_max / 20 and Q_max / 5, both pressure pulsation absorption and system response speed can be balanced. For the hydraulic cylinder in the first embodiment (cylinder diameter 100mm, maximum speed 0.15m / s), the maximum instantaneous displacement Q_max of the rodless chamber is approximately 70.7L / min, corresponding to a recommended range of V_buff of 59mL to 236mL. The 50mL value selected in the first embodiment is near the lower limit of this recommended range, and actual testing has shown that it meets the pulsation suppression requirements and is beneficial for reducing the valve block volume.

[0054] The ratio of the flow area A_orifice of the fixed throttling orifice 6 to the flow area A_main of the main recovery path L5 is a key parameter determining the stage transition time. If this ratio is too large, the flow impact during the flow-limiting access phase will still be significant; if the ratio is too small, the time for the buffer chamber to fill the accumulator will be too long, affecting the recovery efficiency. In this embodiment, A_main is determined by the nominal diameter (DN10) of the hydraulically controlled directional valve 7, and its flow area is approximately 78.5 mm²; the flow diameter φ1.2 mm of the fixed throttling orifice 6 corresponds to a flow area of ​​approximately 1.13 mm², and the ratio is 1.13 / 78.5≈1 / 69, which meets the design principle of not exceeding 1 / 10. Under the conditions of a 3-ton load and a speed of 0.15 m / s, the duration of the flow-limiting access phase is approximately 0.3 seconds, after which it automatically switches to the main recovery path.

[0055] Furthermore, the switching differential pressure threshold ΔP_th of the hydraulically controlled directional valve 7 can be adjusted according to the system's operating pressure level. For medium- and high-pressure systems with operating pressures between 16 and 25 MPa, ΔP_th is recommended to be set between 0.2 MPa and 0.5 MPa. The 0.3 MPa set in the first embodiment falls within this range, and the actual switching process is stable and reliable.

[0056] Example 3: Based on the hardware structure of the first or second example, this example further optimizes the software logic of the controller 400 to more accurately determine whether to maintain the recycling state under varying operating conditions.

[0057] In step S5 of the first embodiment, the calculation method of the estimated recovery benefit E_rec and the estimated additional throttling loss E_loss can be specified as follows: E_rec = ∫P_acc(t)·Q_rec(t)dt (integrated during the main recovery conduction period); E_loss = E_loss_orifice + E_loss_valve; where E_loss_orifice is the throttling loss of the fixed throttling orifice 6 during the flow-limiting access stage, and its value is the integral of ΔP_orifice(t)·Q_orifice(t) during this stage; E_loss_valve is the valve port pressure drop loss of the hydraulic control directional valve 7 in the main recovery passage L5. When E_rec > k·E_loss (k is a preset benefit coefficient, for example, 1.2), the main recovery mode is maintained; otherwise, recovery is exited.

[0058] Furthermore, the controller 400 can also monitor the pressure change rates dP1 / dt in the rodless chamber and dP2 / dt in the rod chamber in real time when the main recovery mode is on. If the absolute value of either rate exceeds a preset threshold (e.g., more than twice the initial stable value), it is determined that a new external disturbance has occurred in the system, and the system actively exits the recovery mode to ensure execution stability.

[0059] It should be noted that the above embodiments and accompanying drawings are merely illustrative examples of the core principles and key structures of the valve block assembly and its control method of the present invention. The accompanying drawings are simplified schematic diagrams, intended to clearly illustrate the structural, process, or data flow relationships related to the innovative points of the technical solution, and are not intended to limit the complete form of the actual product. This specification focuses on the innovative technical means necessary to achieve the invention's objectives and solve the technical problems. While auxiliary or common-sense details such as the selection of dustproof seals, valve block surface treatment processes, fastening bolt specifications, electrical connector models, specific controller brand selections, and conventional filtering algorithms, which can be implemented without creative effort by those skilled in the art, are not elaborated upon, they should all be understood as naturally encompassed in the specific implementation of the present invention and fall within the protection and implementation scope of this technical solution.

Claims

1. An adaptive near bore valve block assembly based on hydraulic potential energy recovery, fixedly connected with a hydraulic cylinder, comprising: A cylinder proximity integrated valve block, an energy storage unit connected to the cylinder proximity integrated valve block, and a controller; characterized in that: the cylinder proximity integrated valve block internally forms: A balanced load-stabilizing path is established to create a basic back pressure when the hydraulic cylinder descends. A pre-charged buffer passage is provided with a one-way throttling element and is connected to a buffer chamber; A current-limiting access path is provided, which has a fixed throttling orifice and connects the buffer chamber to the energy storage unit; The main recovery passage is equipped with a hydraulically controlled directional valve, which is triggered by the difference between the pressure in the buffer chamber and the pressure in the energy storage unit. After the controller outputs a recovery enable signal, the high-pressure return oil automatically and preferentially enters the buffer chamber due to the fast-forward characteristic of the one-way throttling element, and then fills the energy storage unit with a low flow rate through the fixed throttling orifice; when the pressure difference between the buffer chamber and the energy storage unit decreases to a preset threshold, the hydraulic control directional valve automatically switches to conduct the main recovery path, thereby forming a hydraulic automatic graded access sequence that does not depend on the timing command of the controller.

2. The hydraulic potential energy recovery based adaptive near-cylinder valve block assembly of claim 1, wherein, The one-way throttling element is a parallel combination of a one-way valve and a throttling orifice, or an integrated one-way throttling valve; the flow area of ​​the fixed throttling orifice does not exceed 1 / 10 of the flow area of ​​the main recovery passage; the volume of the buffer chamber is set according to 1 / 20 to 1 / 5 of the maximum instantaneous displacement of the rodless chamber of the hydraulic cylinder.

3. The hydraulic potential energy recovery based adaptive near-cylinder valve block assembly of claim 1, wherein, The hydraulic control directional valve is a two-position two-way hydraulic control directional valve, with its first control port connected to the buffer chamber and its second control port connected to the energy storage unit; when the pressure difference between the first control port and the second control port is less than 0.2MPa to 0.5MPa, the hydraulic control directional valve automatically switches to the on position.

4. The adaptive proximity valve block assembly based on hydraulic potential energy recovery according to claim 1, characterized in that, The near-cylinder integrated valve block is provided with a rodless chamber pressure sampling port and a rod chamber pressure sampling port. The flow path length between the sampling port and the corresponding chamber hydraulic channel does not exceed 50mm. Based on the near-cylinder dual-chamber pressure signal obtained by the sampling port, the controller confirms that the system has entered a stable recovery state before the main recovery path is turned on.

5. The adaptive proximity valve block assembly based on hydraulic potential energy recovery according to claim 4, characterized in that, The conditions under which the controller confirms the system has entered a stable recovery state include: the absolute value of the rate of change of pressure in the rodless chamber is less than a first threshold, the absolute value of the rate of change of pressure in the rod chamber is less than a second threshold, and the fluctuation rate of the piston displacement speed is less than a third threshold.

6. The adaptive proximity valve block assembly based on hydraulic potential energy recovery according to claim 1, characterized in that, The cylinder-integrated valve block is also equipped with a safety shut-off passage, which includes a power-off type two-position two-way solenoid valve. When the two-position two-way solenoid valve is de-energized, the connection between the inlet of the main recovery passage and the pre-charge buffer passage and the hydraulic cylinder chamber is cut off, and the system reverts to a safe state in which only the balance and load-stabilizing passage is kept in operation.

7. The adaptive proximity valve block assembly based on hydraulic potential energy recovery according to claim 1, characterized in that, The cylinder-integrated valve block is also equipped with an energy release booster passage. During the lifting phase of the hydraulic cylinder, the energy release booster passage replenishes the pressure oil stored in the energy storage unit to the main oil supply passage via a one-way valve. The energy release booster passage shares the same cylinder-integrated valve block with the pre-charge buffer passage and the main recovery passage, but is isolated by the one-way valve.

8. The adaptive proximity valve block assembly based on hydraulic potential energy recovery according to claim 1, characterized in that, The controller is further configured to: in the main recovery path being open, determine whether to maintain the main recovery path being open based on a comparison between the estimated recovery revenue and the estimated additional throttling loss; the estimated additional throttling loss includes the pressure drop loss generated by the fixed throttling orifice during the current limiting access phase.

9. A control method for an adaptive cylinder proximity valve block assembly based on hydraulic potential energy recovery, wherein the adaptive cylinder proximity valve block assembly is the adaptive cylinder proximity valve block assembly according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. When the hydraulic cylinder is descending or decelerating, keep the balance and load stabilizing passage in working condition to establish a stable load back pressure; S2. When the recovery conditions are detected, the controller outputs a recovery enable signal to open the pre-charge buffer path, so that the high-pressure return oil enters the buffer chamber through the one-way throttling element to absorb the first wave of pressure redistribution at the moment of recovery cut-in; S3. The pressure oil in the buffer chamber is injected into the energy storage unit at a low flow rate through the fixed throttling orifice to mitigate the second wave of flow impact; S4. Monitor the pressure change rate and piston displacement speed in the near-cylinder dual chamber. When the absolute value of the pressure change rate is less than the corresponding threshold and the displacement speed fluctuation rate is less than the preset value, the main recovery path is activated. S5. With the main recovery path open, decide whether to maintain the main recovery mode based on the comparison between the estimated recovery revenue and the estimated additional throttling loss.

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