Composite pressurizing hydraulic cylinder structure of electric hydraulic clamp and control method

Abstract

The invention discloses a composite pressurizing hydraulic cylinder structure of electric hydraulic tongs and a control method, and belongs to the technical field of high-pressure large-flow hydraulic elements and hydraulic systems. The structure comprises a cylinder body, a main piston and a secondary plunger arranged in the main piston in a sliding mode; an annular energy storage cavity is formed between the main piston and the secondary plunger, a floating guide ring is arranged in the annular energy storage cavity to divide the annular energy storage cavity into a high-pressure driving chamber and a low-pressure breathing chamber, and an energy storage elastic piece and a breathing oil drainage channel are arranged in the low-pressure breathing chamber; and a pressure response type flow channel structure is additionally arranged. According to the control method, load abrupt change is judged by monitoring the change rate of input current of the driving motor, and an energy regeneration buffer mode is triggered. Pressure impact energy is converted into elastic potential energy through a flexible buffering mechanism, a motor and a valve are effectively protected, forced reset of the second-stage plunger is achieved through the released potential energy, and the problems of high-pressure adsorption and heat dissipation lubrication are solved.

Description

Technical Field

[0001] This invention relates to the field of high-pressure, high-flow hydraulic components and hydraulic systems, and in particular to a composite booster hydraulic cylinder structure and control method for an electric hydraulic clamp. Background Technology

[0002] In modern industrial automation and power construction equipment, electro-hydraulic actuators are widely used due to their high power density and high output torque. Hydraulic systems typically use miniature piston pumps as the power source, controlling high-pressure hydraulic oil to enter the actuator cylinder via hydraulic valve groups, thereby driving the piston assembly to perform high-load operations such as shearing, pressing, or expanding. To meet the demands for portability and high energy efficiency, hydraulic components are developing towards lighter weight, higher pressure, and more complex fluid control functions.

[0003] In applications involving composite material loads, such as cutting steel-cored aluminum stranded wire, hydraulic actuators face extremely challenging hydrodynamic problems. During operation, the blade first cuts into the relatively soft aluminum matrix, then instantly contacts the extremely hard steel core. This process causes a step-like change in the system load resistance within milliseconds. For high-pressure hydraulic systems, this resistance change translates into a sharp increase in internal system pressure, triggering a sudden surge of large hydraulic flow in local channels. However, existing traditional hydraulic cylinder structures mostly employ rigid transmission connections, lacking effective hydraulic energy buffering and absorption mechanisms. When high-pressure fluid encounters the rigid resistance of a hard load, the incompressible hydraulic oil transmits enormous impact energy in the reverse direction to the drive motor and mechanical transmission chain, causing a sudden surge in motor input current. This not only easily leads to coil overheating and burnout but also causes fatigue damage to precision hydraulic valve components due to the severe pressure impact.

[0004] In addition, under ultra-high pressure conditions, the microscopic physical environment inside hydraulic components also undergoes significant changes. When the pressure inside the hydraulic cylinder reaches above 60 MPa, the rubber seals undergo high-intensity elastic deformation, and the oil film thickness between the metal mating surfaces is extremely compressed, leading to a sharp increase in the static friction coefficient and a significant hydraulic adsorption effect. This causes moving parts such as the secondary plunger to face enormous resistance during the unloading and reset phase. Traditional mechanical reset structures often struggle to overcome this adsorption force, resulting in reset delays or even jamming. At the same time, existing compact hydraulic cylinders often have dead-cavity structures inside, lacking effective fluid exchange channels. The heat generated by high-frequency reciprocating motion is difficult to dissipate through oil circulation, leading to excessively high local oil temperatures, which further accelerates the aging of seals and the carbonization and deterioration of hydraulic oil.

[0005] Therefore, there is an urgent need to develop a new composite booster hydraulic cylinder structure and control method that can ensure the output performance of high-pressure, high-flow hydraulic components while achieving flexible buffering of instantaneous pressure impacts through optimized fluid circuit design, and utilize the breathing and venting characteristics of fluids to solve the problems of high-pressure adsorption and thermal balance, thereby improving the overall reliability and service life of the hydraulic system. Summary of the Invention

[0006] This invention overcomes the shortcomings of the prior art and provides a composite booster hydraulic cylinder structure and control method for an electric hydraulic clamp.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a composite booster hydraulic cylinder structure for an electric hydraulic clamp, comprising:

[0008] The cylinder body is provided with a first oil inlet, which is connected to the hydraulic system.

[0009] The main piston is axially slidably disposed within the cylinder body;

[0010] A secondary plunger, axially slidingly disposed inside the main piston, includes a force-bearing flange and a plunger rod, wherein an annular energy storage chamber is formed between the outer wall of the plunger rod and the inner wall of the main piston;

[0011] A floating guide ring is slidably disposed within the annular energy storage chamber. It serves as a pressure transmission medium and divides the annular energy storage chamber into a high-pressure drive chamber and a low-pressure breathing chamber. It also converts the hydraulic pressure entering the annular energy storage chamber into axial mechanical thrust.

[0012] An energy-storing elastic element is disposed in the low-pressure breathing chamber, with its two ends abutting against the force-bearing flange and the floating guide ring, respectively. It is used to be compressed under the push of the floating guide ring to store elastic potential energy, and to release the elastic potential energy during the unloading phase to provide the power for the reset of the secondary plunger.

[0013] A pressure-responsive flow channel structure, formed on the main piston and cylinder, is used to introduce external hydraulic oil into the high-pressure drive chamber to push the floating guide ring backward and compress the energy storage elastic element; and,

[0014] A breathing oil drain channel is provided in the low-pressure breathing chamber and is connected to the low-pressure oil storage unit of the hydraulic system. It is used to realize the flow of medium in the low-pressure breathing chamber when the energy storage elastic element is compressed or reset.

[0015] In a preferred embodiment of the present invention, the pressure-responsive flow channel structure includes:

[0016] The second oil inlet is located on the side wall of the cylinder and is connected to the hydraulic system.

[0017] Transition chamber, a sealed chamber located between the outer wall of the main piston and the inner wall of the cylinder;

[0018] A flow channel, located on the main piston, connects the transition chamber to the high-pressure drive chamber; and...

[0019] The pressure control valve is located inside the flow channel and is configured to be normally closed, opening only when the hydraulic oil pressure flowing through the flow channel exceeds a preset threshold.

[0020] In a preferred embodiment of the present invention, low-friction combined seals are respectively provided on the inner and outer circumferential surfaces of the floating guide ring to isolate the high-pressure drive chamber from the low-pressure breathing chamber.

[0021] In a preferred embodiment of the present invention, the breathing oil drain channel includes a radial hole formed on the surface of the plunger rod and an inner passage within the central shaft, the inner passage being connected to a low-pressure oil storage unit.

[0022] In a preferred embodiment of the present invention, the energy storage elastic element is a helical metal spring, coaxially sleeved outside the plunger rod. The coil cross-section of the helical metal spring is configured as a fluid turbulence structure to induce the generation of detached vortices to disrupt the laminar boundary layer when hydraulic oil flows through the annular energy storage chamber. Furthermore, a gap is formed between adjacent coils of the helical metal spring, and the gap is configured as a lubricating oil storage space to generate a pumping lubrication effect on the surface of the secondary plunger during compression and rebound.

[0023] A control method for a compound booster hydraulic cylinder of an electro-hydraulic clamp includes the following steps:

[0024] Real-time monitoring of the input current of the drive motor;

[0025] Calculate the rate of change of the input current over time;

[0026] The rate of change is compared with a preset safety threshold; and,

[0027] When the monitored rate of change exceeds the safety threshold, it is determined that a sudden change in load resistance has occurred, and the energy regeneration buffer mode is triggered.

[0028] In a preferred embodiment of the present invention, the energy regeneration buffer mode includes:

[0029] A control command is issued to control the hydraulic system to open the oil supply passage to the second oil inlet on the side wall of the cylinder, so as to allow high-pressure hydraulic oil to enter the transition chamber or directly enter the guide channel through the second oil inlet.

[0030] In a preferred embodiment of the present invention, a reset control step is further included:

[0031] During the reset phase after load cut-off or at the moment of unloading, a control command is issued to control the hydraulic system to stop supplying oil to the second oil inlet or switch to the system unloading state.

[0032] In a preferred embodiment of the present invention, the response time of the rate of change as a control signal is 20 to 50 milliseconds earlier than the pressure build-up time of the pressure sensor inside the hydraulic system, so as to activate the energy regeneration buffer mode before the motor torque reaches a destructive peak.

[0033] In a preferred embodiment of the present invention, the safety threshold is set to correspond to the current rise slope when the cutting blade contacts a hard steel core load:

[0034] When the monitored rate of change is lower than the safety threshold, it is determined that the soft substrate load is being cut, and the system maintains the normal hydraulic propulsion mode and does not open the oil supply passage to the second oil inlet.

[0035] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0036] This invention utilizes fluid dynamics principles to achieve adaptive buffering for sudden load changes by constructing a pressure-responsive flow channel structure containing a transition chamber and a built-in pressure control valve between the main piston sidewall and the cylinder. When the cutting blade contacts the hard steel core, causing a surge in system resistance, the hydraulic oil pressure flowing through the guide channel instantly increases and opens the normally closed pressure control valve, guiding high-pressure fluid into the high-pressure drive chamber to push the floating guide ring backward. This forces the energy storage elastic element to undergo compression deformation between the force-bearing flange and the floating guide ring. The hydraulic surge energy, which would normally cause destructive impacts to the motor and mechanical transmission chain, is converted into the elastic potential energy of the elastic element for temporary storage. This not only effectively reduces the instantaneous peak value of the motor input current and prevents the coil from overheating and burning out, but also avoids the energy waste caused by the pressure relief valve in traditional hydraulic systems, significantly improving the electro-hydraulic energy conversion efficiency of the electro-hydraulic system.

[0037] This invention cleverly solves the problem of hydraulic adsorption and reset hysteresis under ultra-high pressure conditions by utilizing a coaxial series mechanical structure composed of an energy-storing elastic element, a force-bearing flange, and a floating guide ring. During the unloading or reset phase, the enormous potential energy previously forcibly compressed and stored in the elastic element is released instantaneously, realizing energy regeneration. This release force acts directly on the force-bearing flange at the tail end of the secondary plunger, forming an axial mechanical thrust much greater than that of a conventional return spring. This thrust can instantly destroy the static friction force generated by the elastic deformation of the seal under high pressure and the vacuum adsorption force between the metal mating surfaces, achieving forced ejection reset of the secondary plunger. Compared to the frequent "jamming" or "creeping" phenomena caused by relying solely on weak return force in existing technologies, this invention ensures reliable retraction of the hydraulic cylinder after ultra-high pressure operation above 60 MPa, significantly shortening the single operation cycle time.

[0038] This invention innovatively incorporates a breathing and draining channel connecting the low-pressure oil storage unit within the low-pressure breathing chamber, endowing the dead space inside the hydraulic cylinder with a fluid "breathing" function. With the extension and retraction of the secondary plunger, the volume of the low-pressure breathing chamber changes periodically, forcing the medium within the chamber to exchange fluid with the external oil storage unit at high frequency through the breathing and draining channel. This active fluid circulation mechanism of the invention, on the one hand, utilizes the flowing oil to carry away the heat generated by spring compression and sealing friction, preventing aging of the seals due to excessively high local oil temperatures; on the other hand, the micro-turbulence effect generated when the fluid enters and exits the breathing channel effectively disrupts the laminar thermal boundary layer adhering to the plunger rod surface, and utilizes the pumping effect to forcibly establish a hydrodynamic lubrication film on the moving pair surface, thereby fundamentally solving the problem of early failure of compact high-pressure hydraulic components due to poor heat dissipation and insufficient lubrication.

[0039] This invention employs a proactive control strategy based on the rate of change of current, achieving millisecond-level precise identification and response to load attributes. By monitoring the rise rate of the motor current in real time and comparing it with a preset safety threshold, the control system can identify the "hard load" condition and command the opening of the second oil inlet within 20 to 50 milliseconds before the internal pressure of the hydraulic system reaches a destructive peak. This predictive logic based on the differential characteristics of electrical signals overcomes the response lag defect caused by fluid transmission delay in traditional hydraulic pressure sensors, ensuring the timely intervention of the energy regeneration buffer mode. It also enables intelligent and seamless switching between two working modes: rapid propulsion of soft substrates and flexible shearing of hard inclusions, maximizing the service life of the entire machine while ensuring operational efficiency. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a three-dimensional structural diagram of a composite booster hydraulic cylinder structure for an electric hydraulic clamp according to the present invention;

[0042] Figure 2 This is a cross-sectional view of the internal structure of the composite booster hydraulic cylinder structure of an electric hydraulic clamp according to the present invention;

[0043] Figure 3 This is a state diagram of the present invention when the main piston is moving and the secondary plunger is not moving;

[0044] Figure 4This is a state diagram of the secondary plunger and floating guide ring of the present invention during movement;

[0045] Figure 5 This is a schematic diagram of the structure of the breathing oil drain channel of the present invention;

[0046] Figure 6 This is a flowchart of a control method for a composite booster hydraulic cylinder of an electric hydraulic clamp according to the present invention;

[0047] In the diagram: a) High-pressure drive chamber; b) Low-pressure breathing chamber; 1) Cylinder block; 2) First oil inlet; 3) Main piston; 4) Secondary plunger; 401) Force-bearing flange; 402) Plunger rod; 5) Annular accumulator chamber; 6) Floating guide ring; 7) Energy storage elastic element; 701) Helical metal spring; 8) Pressure-responsive flow channel structure; 801) Second oil inlet; 802) Transition chamber; 803) Guide flow channel; 804) Pressure control valve; 9) Breathing drain channel; 901) Radial hole; 902) Internal flow channel; 10) Low-pressure oil storage unit. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0050] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0051] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0052] like Figure 1 and Figure 2 As shown, a composite booster hydraulic cylinder structure for an electric hydraulic clamp includes:

[0053] The cylinder body 1 is provided with a first oil inlet 2, which is connected to the hydraulic system;

[0054] The main piston 3 is axially slidably disposed within the cylinder body 1;

[0055] The secondary plunger 4 is axially slidably disposed inside the main piston 3, and includes a force-receiving flange 401 and a plunger rod 402. An annular energy storage chamber 5 is formed between the outer wall of the plunger rod 402 and the inner wall of the main piston 3.

[0056] The floating guide ring 6 is slidably disposed in the annular energy storage chamber 5, serving as a pressure transmission medium and dividing the annular energy storage chamber 5 into a high-pressure drive chamber a and a low-pressure breathing chamber b, and converting the hydraulic pressure entering the annular energy storage chamber 5 into axial mechanical thrust.

[0057] An energy-storing elastic element 7 is disposed in the low-pressure breathing chamber b, with its two ends abutting against the force-bearing flange 401 and the floating guide ring 6 respectively. It is used to be compressed under the push of the floating guide ring 6 to store elastic potential energy, and to release the elastic potential energy during the unloading stage to provide the power for the reset of the secondary plunger 4.

[0058] A pressure-responsive flow channel structure 8, formed on the main piston 3 and cylinder 1, is used to introduce external hydraulic oil into the high-pressure drive chamber a to push the floating guide ring 6 backward and compress the energy storage elastic element 7; and,

[0059] Breathing oil drain channel 9 is provided in the low-pressure breathing chamber b and is connected to the low-pressure oil storage unit 10 of the hydraulic system. It is used to realize the flow of medium in the low-pressure breathing chamber b when the energy storage elastic element 7 is compressed or reset.

[0060] Existing electro-hydraulic tools mostly use a rigid hydraulic transmission link of "pump-valve-cylinder". When the cutting blade comes into contact with the hard steel core from the soft substrate, the sudden change in load resistance will cause the internal pressure of the system to rise sharply. In the absence of a buffer mechanism, this hydraulic surge will directly backfire on the drive motor and precision valves, causing equipment overload damage. At the same time, under ultra-high pressure conditions, the elastic deformation of the seals and the molecular adsorption effect on the metal surface will cause the "hydraulic lock" phenomenon, making it difficult for the secondary plunger 4 to reset after unloading. This invention reconstructs the force transmission path from a physical mechanism by introducing an embedded flexible buffer and energy regeneration system composed of a floating guide ring 6, an energy storage elastic element 7, and a pressure-responsive flow channel structure 8: at the instant of sudden load change, the bypass buffer channel is automatically opened using the principle of fluid dynamics to temporarily store the destructive hydraulic impact energy into the elastic potential energy of the elastic element; during the unloading and reset phase, the released elastic potential energy is used to generate an explosive mechanical thrust, forcibly breaking the hydraulic adsorption force to achieve ejection reset; at the same time, the volume change of the low-pressure breathing chamber b drives the medium to perform high-frequency swallowing and spitting through the breathing oil drain channel 9, giving the dead space a fluid "breathing" function, thereby fundamentally solving the heat dissipation and lubrication problems of compact high-pressure components.

[0061] The following will describe in detail the specific implementation and working process with reference to the accompanying drawings and multiple embodiments. Throughout this specification, the definition of orientation is based on the axial centerline of the hydraulic cylinder. The end closer to the oil inlet of the hydraulic system is defined as the rear or near end, and the end farther from the oil inlet where the secondary plunger 4 extends is defined as the front or far end. This orientation definition is only for the convenience of describing the relative positional relationship between the components and should not be construed as a limitation on the scope of protection of this invention.

[0062] Example 1:

[0063] This embodiment provides a composite booster hydraulic cylinder structure for an electric hydraulic clamp, aiming to solve the technical problems of existing high-flow, high-pressure hydraulic components lacking a flexible buffer mechanism when facing sudden changes in load resistance and difficulty in resetting under ultra-high pressure conditions. Figure 2 As shown, the composite booster hydraulic cylinder structure mainly consists of a cylinder body 1, a main piston 3, a secondary plunger 4, and an embedded buffer energy storage system built between the main piston 3 and the secondary plunger 4.

[0064] The cylinder body 1 serves as the basic support component of the entire hydraulic cylinder. Its side wall is provided with a first oil inlet 2, which is adapted to the main drive oil circuit of the hydraulic system and is used to introduce the main drive hydraulic oil from the hydraulic pump. The main piston 3 is axially slidably disposed in the inner cavity of the cylinder body 1, and a sealing component is provided between its outer circumferential surface and the inner wall of the cylinder body 1 to form a dynamic sealing fit. The interior of the main piston 3 is not a solid structure, but has an axially oriented accommodating space, which provides a physical basis for the installation of the secondary plunger 4. The secondary plunger 4 is coaxially slidably disposed in the accommodating space of the main piston 3. This double-stage nested piston structure enables the hydraulic cylinder to achieve a larger extension stroke within a limited axial length. To achieve mechanical decoupling and functional synergy between the secondary plunger 4 and the main piston 3, this embodiment innovatively decomposes and defines the structure of the secondary plunger 4, specifically dividing it into a force-bearing flange 401 located at the rear end and a plunger rod 402 located at the front end and extending outward. The force-bearing flange 401 is a radially convex annular structure at the tail end of the secondary plunger 4, and its outer diameter is adapted to the inner diameter of the main piston 3, serving as the main force-bearing surface of the secondary plunger 4 during the reset process. The plunger rod 402 is the main body of the secondary plunger 4, and its outer diameter is smaller than that of the force-bearing flange 401, thereby forming a slender annular space between the outer wall of the plunger rod 402 and the inner wall of the main piston 3, which is the core annular energy storage cavity 5 of this invention.

[0065] In traditional hydraulic cylinder designs, the main piston 3 and the secondary plunger 4 are typically connected by rigid contact or a simple limiting structure. When the external load changes drastically, the impact energy is transmitted between the pistons without any attenuation. To break this rigid transmission chain, this embodiment provides a floating guide ring 6 and an energy storage elastic element 7 within the aforementioned annular energy storage chamber 5. The floating guide ring 6 is an annular piston-shaped assembly that can slide independently axially. Its sealed sliding arrangement within the annular energy storage chamber 5 tightly separates the originally connected annular energy storage chamber 5 into two independent chambers in physical space: a high-pressure drive chamber a located in front of the floating guide ring 6 and a low-pressure breathing chamber b located behind the floating guide ring 6 and housing the energy storage elastic element 7. The floating guide ring 6 plays a crucial role as the pressure transmission medium in this invention. It can convert the hydraulic fluid pressure entering the high-pressure drive chamber a into an axial mechanical thrust that compresses the energy storage elastic element 7. At the same time, it uses its sealing characteristics to isolate the high-pressure oil circuit from the low-pressure breathing circuit, preventing high-pressure oil from directly entering the chamber where the spring is located and causing hydraulic lock-up.

[0066] The energy-storing elastic element 7 is disposed in the low-pressure breathing chamber b, with one end axially abutting the front end face of the force-bearing flange 401 and the other end axially abutting the rear end face of the floating guide ring 6. In this embodiment, the energy-storing elastic element 7 is preferably a high-stiffness helical metal spring 701, which is coaxially sleeved on the outside of the plunger rod 402, forming a unique coaxial series mechanical structure: in the static or conventional propulsion state, the energy-storing elastic element 7 is in a pre-compressed state, and the elastic pre-tightening force it generates pushes the force-bearing flange 401 backward and pushes the floating guide ring 6 forward, so that the secondary plunger 4 maintains a stable contracted position relative to the main piston 3; in the dynamic buffer state, when the floating guide ring 6 is pushed backward by the oil pressure in the high-pressure drive chamber a, the floating guide ring 6 will compress the energy-storing elastic element 7, converting the pressure peak energy of the hydraulic system into elastic potential energy stored in the lattice deformation of the spring.

[0067] To ensure that the main piston 3 can drive the secondary plunger 4 for regular extension operations, a connecting hole is provided at the bottom of the main piston 3, which connects the oil inlet chamber behind the main piston 3 with the internal accommodating space of the main piston 3. When the hydraulic cylinder is performing unloaded rapid advance or cutting soft substrate loads (such as aluminum stranded wire), hydraulic oil enters the cylinder body 1 through the first oil inlet 2, initially pushing the main piston 3 forward. When the main piston 3's movement is obstructed or the secondary plunger 4 needs to extend, the hydraulic oil acts directly on the rear end face of the force-bearing flange 401 of the secondary plunger 4 through the connecting hole at the bottom, driving the secondary plunger 4 to extend forward. During this process, since the pressure in the high-pressure drive chamber a is not yet sufficient to overcome the preload of the energy storage elastic element 7, the floating guide ring 6 remains relatively stationary, and the entire hydraulic cylinder exhibits standard two-stage extension characteristics, ensuring operational efficiency.

[0068] However, the structural advantages of this embodiment are fully demonstrated when the hydraulic cylinder enters the unloading stage or needs to be reset after the operation is completed. Under ultra-high pressure conditions, such as pressure exceeding 60 MPa, the seal of the secondary plunger 4 undergoes severe elastic deformation and embeds itself into the microscopic gaps in the metal. At the same time, the extremely thin oil film between the mating surfaces generates a huge molecular adsorption force, which in the prior art often causes the secondary plunger 4 to be stuck and unable to retract. In this embodiment, once the system is unloaded, the energy-storing elastic element 7, which was forcibly compressed in the buffer stage, will instantly release its stored huge elastic potential energy. This release force acts directly on the force-bearing flange 401, forming an axial reset thrust that is much greater than the sealing static friction force and the hydraulic adsorption force, forcibly pushing the secondary plunger 4 to retract backward relative to the main piston 3, achieving a rapid ejection-type reset. This design utilizes the law of conservation of energy, converting the hydraulic impact energy during the operation into mechanical kinetic energy during reset, which not only solves the jamming problem but also realizes the internal regeneration of energy.

[0069] Example 2:

[0070] This embodiment, based on the mechanical structure provided in Embodiment 1, further details how to achieve adaptive buffering for sudden load changes, focusing on the specific construction of the pressure-responsive flow channel structure 8 and its fluid dynamics principles. When cutting composite materials such as steel-cored aluminum stranded wire, the system load resistance undergoes a step-like change within milliseconds at the instant the blade transitions from cutting into the soft aluminum layer to contacting the hard steel core. This sudden change in resistance causes a sharp rise in internal pressure of the hydraulic system, which, if not controlled, will cause destructive impact on the motor and mechanical transmission chain.

[0071] To address the aforementioned issues, this embodiment constructs a precise pressure-responsive flow channel structure 8 between the side wall of the main piston 3 and the cylinder 1. This includes a second oil inlet 801 located on the side wall of the cylinder 1, independent of the first oil inlet 2, specifically designed to introduce external high-pressure hydraulic oil for a buffering function. Since the main piston 3 undergoes a long axial movement relative to the cylinder 1 during operation, to ensure that the second oil inlet 801 on the cylinder 1 remains connected to the flow channel on the main piston 3 throughout its entire effective working stroke, this embodiment forms a transition chamber 802 between the outer wall of the main piston 3 and the inner wall of the cylinder 1. This ensures that regardless of whether the main piston 3 is extended or retracted, external high-pressure oil can smoothly enter the flow channel system of the main piston 3.

[0072] Inside the side wall of the main piston 3, a flow channel 803 is also provided, with its inlet connected to the aforementioned transition chamber 802 and its outlet connected to the high-pressure drive chamber a within the annular energy storage chamber 5. To achieve intelligent pressure response, a pressure control valve 804 is built into the flow channel 803. This pressure control valve 804 is configured to be normally closed and has a preload spring and valve core inside. It will only open when the hydraulic oil pressure at the inlet of the flow channel 803 exceeds a preset threshold. This preset threshold is usually set to be slightly higher than the pressure required to cut the soft substrate, but much lower than the system's safe overflow pressure.

[0073] When the hydraulic cylinder is in the normal propulsion mode, the system pressure is lower than the opening threshold of the pressure control valve 804, the valve remains closed, the high-pressure drive chamber a is isolated from the external oil circuit, and the floating guide ring 6 is held at the front end position under the thrust of the energy storage elastic element 7. The hydraulic cylinder exhibits rigid transmission, ensuring the propulsion speed. When the blade contacts the hard steel core, causing a sudden change in resistance, the hydraulic system detects this change and commands the opening of the oil supply passage to the second oil inlet 801. At this time, high-pressure hydraulic oil quickly fills the guide channel 803 and builds up a pressure exceeding the threshold in a very short time, thereby instantly opening the valve core of the pressure control valve 804. The high-pressure oil then rushes into the high-pressure drive chamber a and acts on the rear end face of the floating guide ring 6. Since the hydraulic oil is incompressible while the energy storage elastic element 7 is compressible, the rushing high-pressure oil will push the floating guide ring 6 to move backward, forcing the energy storage elastic element 7 to undergo compression deformation between the force-bearing flange 401 and the floating guide ring 6.

[0074] This process manifests as a "peak shaving and valley filling" effect in fluid dynamics: the hydraulic surge energy that would normally cause a sudden spike in system pressure is diverted into the high-pressure drive chamber a and converted into the elastic potential energy of the spring, thereby reducing the pressure peak of the main oil circuit and preventing excessive back electromotive force fluctuations caused by sudden torque changes in the motor. Simultaneously, the pressure control valve 804 also has a reverse flow function or is connected in parallel with a reverse check valve. During the system unloading and reset phase, when the floating guide ring 6 is pushed back by the spring, the stagnant oil in the high-pressure drive chamber a can flow out in reverse through the pressure control valve 804 and ultimately return to the oil tank, ensuring a smooth reset operation.

[0075] Example 3:

[0076] This embodiment focuses on solving the thermal balance and lubrication problems inside compact high-pressure hydraulic components, and elaborates in detail on the construction of the low-pressure breathing chamber b and the breathing oil drain channel 9 and the resulting thermodynamic and tribological effects. In existing hydraulic cylinder designs, the chamber where the spring is located is usually a closed dead cavity, where the heat generated by high-frequency reciprocating motion is difficult to dissipate, and the closed gas or liquid will form an air spring or hydraulic lock, hindering piston movement.

[0077] To give the dead cavity inside the hydraulic cylinder a fluid "breathing" function, this embodiment provides a breathing oil drain channel 9 in the low-pressure breathing chamber b. This channel connects the low-pressure breathing chamber b with the low-pressure oil storage unit 10 of the hydraulic system and can be optionally configured as an oil tank. Specifically, the breathing oil drain channel 9 includes a radial hole 901 opened on the surface of the plunger rod 402 located in the low-pressure breathing chamber b, and an inner flow channel 902 axially opened in the central axis of the plunger rod 402. One end of the inner flow channel 902 is connected to the radial hole, and the other end is connected to the low-pressure oil storage unit 10. By utilizing the structural space of the plunger rod 402 itself, complex external pipelines are avoided on the main piston 3 or cylinder 1. At the same time, since the central flow channel is always in a low-pressure state, the problem of high-pressure dynamic sealing is also solved.

[0078] As the secondary plunger 4 extends and retracts, and the floating guide ring 6 reciprocates, the volume of the low-pressure breathing chamber b changes periodically. During the buffering phase, when the energy storage elastic element 7 is compressed, the volume of the low-pressure breathing chamber b decreases, and the medium originally present in the chamber is squeezed and enters the inner passage 902 through the radial hole 901, and is finally discharged to the low-pressure oil storage unit 10. This process quickly removes the heat generated by the spring compression and the heat generated by the sealing friction from the cylinder body 1, preventing the aging of the seal ring and the carbonization of the hydraulic oil caused by excessive local oil temperature.

[0079] During the reset phase, when the energy storage elastic element 7 extends and resets, the volume of the low-pressure breathing chamber b increases, generating negative pressure. Fresh, low-temperature hydraulic oil from the external low-pressure oil storage unit 10 is drawn into the low-pressure breathing chamber b through the inner passage 902 and the radial through hole. This process not only replenishes the medium but also produces a significant pumping lubrication effect tribologically. To enhance this effect, the energy storage elastic element 7 in this embodiment is preferably a helical metal spring 701, with lubricating oil storage gaps defined between adjacent coils. When low-temperature oil is drawn in, it fills these gaps. When the spring is compressed again, the gaps become smaller, and the oil is squeezed out and sprayed onto the surface of the plunger rod 402 in the form of a jet.

[0080] From a fluid mechanics perspective, the coil cross-section of the helical metal spring 701 is configured as a fluid turbulence structure. When the oil flows through the spring coil during the breathing process, the circular steel wire cross-section induces the fluid to generate detached vortices behind it, i.e., Karman vortex streets. These tiny turbulent vortices can violently agitate the fluid, effectively disrupting the laminar thermal boundary layer attached to the inner wall of the plunger rod 402 and the main piston 3, greatly improving the convective heat transfer coefficient. Through this active fluid circulation and micro-turbulent disturbance, this embodiment fundamentally solves the problem of early failure caused by poor heat dissipation in compact high-pressure hydraulic components, achieving self-cooling and self-lubrication of the hydraulic cylinder.

[0081] Example 4:

[0082] This embodiment provides a control method applied to the aforementioned composite booster hydraulic cylinder structure. This method, based on the advance feedback logic of the motor current change rate (dI / dt), achieves intelligent identification of both soft and hard loads and precise triggering of the energy regeneration buffer mode. Traditional hydraulic control systems often rely on pressure sensors for feedback; however, due to the compressibility of hydraulic oil and the delay in pipeline transmission, the pressure signal often lags behind the actual load changes, resulting in untimely buffer intervention.

[0083] The control system in this embodiment includes a current sensor connected in series in the drive motor circuit, a microprocessor controller, and a solenoid valve group for controlling the on / off state of the hydraulic system's oil circuit. The control method first performs a real-time monitoring step, acquiring the input current signal of the drive motor through the current sensor at a high-frequency sampling rate. Subsequently, the microprocessor performs differentiation on the acquired current signal to calculate the rate of change of the input current over time, dI / dt. This rate of change directly reflects the instantaneous change in the motor's output torque, and since torque is proportional to the load resistance experienced by the blades, dI / dt is the most sensitive parameter characterizing the characteristics of sudden load changes.

[0084] After calculating the rate of change, the system compares it with a preset safety threshold. This safety threshold is set based on the typical current rise slope when the cutting blade contacts a hard steel core load. If the monitored rate of change is lower than the safety threshold, the controller determines that the current condition is either cutting a soft substrate load (such as aluminum stranded wire) or an unloaded condition. At this time, the system maintains the normal hydraulic propulsion mode, does not send an opening signal to the solenoid valve that controls the on / off state of the second oil inlet 801, the pressure-responsive flow channel structure 8 is in a dormant state, and the hydraulic cylinder performs rigid propulsion with maximum efficiency, avoiding unnecessary energy loss.

[0085] Once the detected rate of change exceeds the safety threshold, the controller determines that a sudden change in load resistance has occurred, i.e., the steel core has been cut off, and immediately triggers the energy regeneration buffer mode. In this mode, the controller issues a control command to drive the solenoid valve of the hydraulic system to open the oil supply passage to the second oil inlet 801 on the side wall of cylinder 1. The high-pressure hydraulic oil then enters the transition chamber 802 through the second oil inlet 801 and fills the guide channel 803 on the main piston 3. When the pressure of the filled hydraulic oil breaks through the pressure control valve 804 in the guide channel 803, the hydraulic oil rushes into the high-pressure drive chamber a, using the rushing high-pressure hydraulic oil to push the floating guide ring 6 backward and forcibly compress the energy storage elastic element 7. The response time of this control action is 20 to 50 milliseconds earlier than the pressure establishment time of the pressure sensor inside the hydraulic system, ensuring that the buffer mechanism has fully intervened before the motor torque reaches the destructive peak, thereby effectively protecting the motor and mechanical structure.

[0086] During the reset phase after load cutoff or at the moment of unloading, the controller issues a reset control command to stop the hydraulic system from supplying oil to the second oil inlet 801 or switch to the system unloading state. At this time, the external high-pressure source is cut off, and the energy storage elastic element 7 releases the stored elastic potential energy. This mechanical thrust acts directly on the force-bearing flange 401, overcoming static friction to achieve rapid reset of the secondary plunger 4. Simultaneously, external fluid is drawn into the low-pressure breathing chamber b through the breathing oil drain channel 9, completing a complete thermal balance and lubrication cycle. Through this deep integration of hardware and software, this embodiment achieves intelligent adaptation and efficient management of complex working conditions. The above description is based on the ideal embodiment of the present invention. Based on the above description, those skilled in the art can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A composite booster hydraulic cylinder structure for an electric hydraulic clamp, characterized in that, include: The cylinder body (1) is provided with a first oil inlet (2), which is connected to the hydraulic system; The main piston (3) is axially slidably disposed within the cylinder body (1); The secondary plunger (4) is axially slidably disposed inside the main piston (3), including a force-bearing flange (401) and a plunger rod (402). An annular energy storage cavity (5) is formed between the outer wall of the plunger rod (402) and the inner wall of the main piston (3). The floating guide ring (6) is sealed and slidably disposed in the annular energy storage chamber (5) to serve as a pressure transmission medium and to divide the annular energy storage chamber (5) into a high-pressure drive chamber (a) and a low-pressure breathing chamber (b), and to convert the hydraulic pressure entering the annular energy storage chamber (5) into axial mechanical thrust. An energy storage elastic element (7) is disposed in the low-pressure breathing chamber (b), with its two ends abutting against the force-bearing flange (401) and the floating guide ring (6) respectively. It is used to be compressed under the push of the floating guide ring (6) to store elastic potential energy, and to release the elastic potential energy during the unloading stage to provide the power for the reset of the secondary plunger (4). A pressure-responsive flow channel structure (8), formed on the main piston (3) and cylinder (1), is used to introduce external hydraulic oil into the high-pressure drive chamber (a) to push the floating guide ring (6) backward and compress the energy storage elastic element (7); and, The breathing oil drain channel (9) is provided in the low-pressure breathing chamber (b) and is connected to the low-pressure oil storage unit (10) of the hydraulic system. It is used to realize the swallowing and spitting flow of the medium in the low-pressure breathing chamber (b) when the energy storage elastic element (7) is compressed or reset.

2. The composite booster hydraulic cylinder structure of an electric hydraulic clamp according to claim 1, characterized in that, The pressure-responsive flow channel structure (8) includes: The second oil inlet (801) is located on the side wall of the cylinder (1) and is connected to the hydraulic system; The transition chamber (802) is a sealed chamber located between the outer wall of the main piston (3) and the inner wall of the cylinder (1); A flow channel (803) is formed on the main piston (3) and connects the transition chamber (802) to the high-pressure drive chamber (a); and, The pressure control valve (804) is located inside the flow channel (803) and is configured to be normally closed, opening only when the pressure of the hydraulic oil flowing through the flow channel (803) exceeds a preset threshold.

3. The composite booster hydraulic cylinder structure of an electric hydraulic clamp according to claim 1, characterized in that, The floating guide ring (6) is provided with low-friction combined seals on its inner and outer circumferential surfaces to isolate the high-pressure drive chamber (a) from the low-pressure breathing chamber (b).

4. The composite booster hydraulic cylinder structure of an electric hydraulic clamp according to claim 1, characterized in that, The breathing oil drain channel (9) includes a radial hole (901) formed on the surface of the plunger rod (402) and an inner passage (902) in the central shaft, the inner passage (902) being connected to the low-pressure oil storage unit (10).

5. The composite booster hydraulic cylinder structure of an electric hydraulic clamp according to claim 1, characterized in that, The energy storage elastic element (7) is a helical metal spring (701), which is coaxially sleeved outside the plunger rod (402). The coil cross section of the helical metal spring (701) is configured as a fluid turbulence structure to induce the generation of detached vortices to disrupt the laminar boundary layer when hydraulic oil flows through the annular energy storage chamber (5). Furthermore, a gap is formed between adjacent coils of the helical metal spring (701), which is configured as a lubricating oil storage space to generate a pumping lubrication effect on the surface of the secondary plunger (4) during compression and rebound.

6. A control method for a composite booster hydraulic cylinder of an electric hydraulic clamp, applied to the hydraulic cylinder structure described in any one of claims 1 to 5, characterized in that, Includes the following steps: Real-time monitoring of the input current of the drive motor; Calculate the rate of change of the input current over time; The rate of change is compared with a preset safety threshold. as well as, When the monitored rate of change exceeds the safety threshold, it is determined that a sudden change in load resistance has occurred, and the energy regeneration buffer mode is triggered.

7. The control method for the composite booster hydraulic cylinder of an electric hydraulic clamp according to claim 6, characterized in that, The energy regeneration buffer mode includes: A control command is issued to control the hydraulic system to open the oil supply passage to the second oil inlet (801) on the side wall of the cylinder (1), so as to allow high pressure hydraulic oil to enter the transition chamber (802) or directly enter the guide channel (803) via the second oil inlet (801).

8. The control method for the composite booster hydraulic cylinder of an electric hydraulic clamp according to claim 7, characterized in that, It also includes a reset control step: During the reset phase after the load is cut off or at the moment of unloading, a control command is issued to control the hydraulic system to stop supplying oil to the second oil inlet (801) or switch to the system unloading state.

9. The control method for the composite booster hydraulic cylinder of an electric hydraulic clamp according to claim 6, characterized in that, The rate of change, as a control signal, responds 20 to 50 milliseconds earlier than the pressure build-up time of the internal pressure sensor of the hydraulic system, in order to activate the energy regeneration buffer mode before the motor torque reaches a destructive peak.

10. The control method for the composite booster hydraulic cylinder of an electric hydraulic clamp according to claim 6, characterized in that, The safety threshold is set to correspond to the current rise slope when the cutting blade contacts the hard steel core load: When the monitored rate of change is lower than the safety threshold, it is determined that the soft substrate load is being cut, and the system maintains the normal hydraulic propulsion mode and does not open the oil supply passage to the second oil inlet (801).

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