Energy-saving cylinder

Abstract

The invention relates to the field of air cylinders, and discloses an energy-saving air cylinder which comprises an air cylinder body, an energy-saving control module and a pilot control module which are integrated at one end of the air cylinder body, and further comprises a position detection unit which comprises a magnetic switch arranged on the air cylinder body and is used for sensing the movement speed of a piston; the locking mechanism comprises a conical recovery column arranged at the end of the piston, and an annular groove is formed in the surface of the conical recovery column; the double-cavity recovery assembly is arranged in an end cover of the air cylinder body and converts kinetic energy generated when a piston retreats into high-pressure potential energy, the high-pressure potential energy is precisely shunted, one part is used for achieving buffering and locking, the other part is recovered through an energy storage cavity, gas collected into the energy storage cavity is released through a pre-charging loop at the moment of starting of the next cycle, consumption of a main gas source is remarkably reduced, and the service life of the main gas source is prolonged. The conical recovery column is matched with the elastic cavity, so that mechanical oscillation is eliminated, and the fatigue life of the sealing piece and the cylinder body is prolonged.

Description

Technical Field

[0001] This invention relates to the field of cylinders, and more particularly to an energy-saving cylinder. Background Technology

[0002] With the rapid development of industrial automation, pneumatic actuators have been widely used in robotic arms, production lines, and various precision machining equipment. Compressed air, as the power source for pneumatic systems, accounts for a significant proportion of industrial electricity consumption. Therefore, developing energy-efficient cylinders has become an important research direction in the field of pneumatic technology.

[0003] Existing energy-saving solutions mostly focus on reducing intake air volume, while the residual compressed air expelled by the piston during its retraction stroke is usually directly discharged into the atmosphere. This not only wastes the pressure energy contained in the exhaust, but the noise generated during exhaust is also a major source of pollution in industrial environments. Because gases are compressible, the piston is prone to displacement deviation when external loads change abruptly or the supply pressure fluctuates. Although mechanical pin-type locking cylinders exist on the market, their complex structure, high wear, and often require an additional power source to drive the locking action do not align with the development trend of integration and energy conservation. Summary of the Invention

[0004] The purpose of this invention is to provide an energy-saving cylinder to solve the above-mentioned problems. The specific technical solution is as follows: An energy-saving cylinder includes a cylinder body, an energy-saving control module integrated at one end of the cylinder body, and a pilot control module, and further includes: The position detection unit includes a magnetic switch disposed on the cylinder body for sensing the movement speed of the piston; The locking mechanism includes a tapered recovery post disposed at the end of the piston, the surface of which is provided with an annular groove; A dual-chamber recovery assembly is disposed inside the end cover of the cylinder body, including a first elastic recovery sealing chamber and a second elastic recovery sealing chamber. The first elastic recovery sealing chamber is used to cooperate with the conical recovery column for deceleration and buffering, and the second elastic recovery sealing chamber is used to embed into the annular groove to achieve position locking. An adaptive control loop is connected to the cylinder body, the dual-chamber recovery assembly, and the position detection unit, respectively, and is used to dynamically adjust the air pressure in the dual-chamber recovery assembly according to the speed signal fed back by the position detection unit through the energy-saving control module.

[0005] As one of the improvements to the above technical solution, the conical recovery column has a cone structure with a gradually changing cross-section. When it enters the first elastic recovery sealing cavity, the exhaust gap formed with the inner wall of the cavity gradually decreases as the stroke goes deeper, thereby generating a linearly increasing back pressure resistance to achieve piston deceleration.

[0006] As one of the improvements to the above technical solution, the adaptive control loop includes a one-way recovery valve and an energy storage chamber. The first elastic recovery sealing chamber is connected to the energy storage chamber through the one-way recovery valve. The high-pressure gas compressed during the buffering process is recovered to the energy storage chamber through the one-way recovery valve.

[0007] As an improvement to the above technical solution, a cascaded trigger valve is provided between the first elastic recovery sealing chamber and the second elastic recovery sealing chamber; when the piston moves to a predetermined position and the pressure in the first elastic recovery sealing chamber reaches a preset threshold, the cascaded trigger valve opens, guiding the recovered high-pressure gas into the second elastic recovery sealing chamber.

[0008] As an improvement to the above technical solution, the second elastic recovery sealing cavity has an elastic inner edge that can contract centripetally. When the cavity is filled with high-pressure gas, the inner edge deforms and embeds into the annular groove on the surface of the conical recovery column.

[0009] As an improvement to the above technical solution, the adaptive control loop also includes an intelligent processing unit that, based on the real-time speed calculated by the position detection unit, determines that the speed exceeds a safety threshold. If the speed exceeds the threshold, the unit then drives the proportional adjustment valve in the energy-saving control module to reduce the initial exhaust diameter, thereby enhancing the intervention strength of the first elastic recovery sealing chamber in the initial buffering stage.

[0010] As one of the improvements to the above technical solution, the recovered gas in the energy storage chamber is connected to the working air inlet of the cylinder through a pre-charge circuit to provide auxiliary thrust at the moment the piston starts.

[0011] The beneficial effects of this invention are as follows: the kinetic energy of the piston retraction is converted into high-pressure potential energy and precisely diverted. Part of the energy is used for buffering and locking, while the other part is recovered through the energy storage chamber. The gas collected in the energy storage chamber is released through the pre-charge circuit at the moment of the next cycle start, which significantly reduces the consumption of the main gas source. The conical recovery column and the elastic chamber work together to eliminate mechanical vibration and extend the fatigue life of the seals and cylinder.

[0012] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0013] 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 of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the structure of the present invention.

[0015] Figure 2 This is a schematic diagram of the dual-cavity recovery assembly of the present invention.

[0016] In the diagram: 1. Cylinder body; 2. Position detection unit; 3. Dual-chamber recovery assembly; 4. Locking mechanism; 5. Adaptive control loop; 11. Piston; 31. First elastic recovery sealing chamber; 32. Second elastic recovery sealing chamber; 33. Cascade trigger valve; 41. Conical recovery column; 42. Annular groove; 51. One-way recovery valve; 52. Energy storage chamber; 53. Intelligent processing unit. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0018] Please see Figure 1 and Figure 2 The present invention provides an energy-saving cylinder, the structure of which includes a cylinder body 1, an energy-saving control module and a pilot control module integrated at one end of the cylinder body 1, and also includes a position detection unit 2, a locking mechanism 4, a dual-chamber recovery assembly 3 and an adaptive control loop 5.

[0019] The cylinder body 1 is made of high-strength aluminum alloy, and its inner wall can be treated with hard anodizing. At one end of the cylinder body 1 (usually the rodless end cap area), an energy-saving control module and a pilot control module are integrated. The two form a compact control unit through an embedded PCB board and a miniature solenoid valve assembly, which is encapsulated in a housing and shares a mounting flange with the cylinder body 1, requiring no additional brackets or external piping.

[0020] Traditional energy-saving devices (such as throttle valves and proportional valves) and control units are mostly installed separately, which not only occupies a lot of space, but also causes response delays due to excessively long connecting pipelines, easily leading to control lag in high-speed automated production lines. At the same time, external interfaces are prone to loosening and leakage in vibration environments, reducing system reliability. This implementation method, through high integration, shortens the control signal path to the centimeter level, eliminates external leakage points, and improves system response speed and sealing reliability.

[0021] Conventional cylinders rely solely on a single-point limit switch to determine the position, making it impossible to obtain speed information of the piston 11 during dynamic processes. When the load changes abruptly (such as when a robotic arm grips / releases a workpiece) or the air supply pressure fluctuates, the piston 11 may impact the end cap with excessively high residual velocity, causing impact noise, cylinder damage, or even positioning failure.

[0022] Therefore, the position detection unit 2 of the present invention consists of at least two magnetic switches, which are respectively installed on the outer wall of the cylinder body 1 at two preset positions near the end of the stroke (e.g., 40mm and 80mm from the end cap). The magnetic switches integrate Hall elements and are non-contactly coupled to the permanent magnet ring built into the piston 11, outputting position pulse signals in real time. The microcontroller (MCU) in the energy-saving control module calculates the current movement speed of the piston 11 based on the trigger time difference of the two switches, providing key input for subsequent buffering and locking control, and avoiding the risk of hard landing.

[0023] In most cases, the cylinder lacks an effective holding mechanism in the stopped position. Due to the compressibility of compressed air and external disturbances (such as vibration and load changes), the piston 11 is prone to micro-displacement and pneumatic drift, which makes it difficult to meet the requirements of precision assembly or positioning. Existing mechanical locking cylinders require an additional drive source (such as hydraulic or pneumatic) to push the locking pin, which is complex in structure, suffers from severe wear, and increases energy consumption.

[0024] Therefore, the present invention also provides some embodiments. Specifically, the core component of the locking mechanism 4 is a tapered recovery column 41 disposed at the end of the piston rod 11. Its cross-section is tapered (preferably with a cone angle of 3°-8°), and one or more annular grooves 42 are machined on its surface. This structure moves together with the piston 11 and enters the dual-chamber recovery assembly 3 in the end cap at the end of its stroke.

[0025] The dual-chamber recovery assembly 3 is integrally embedded inside the cylinder end cover, comprising a first elastic recovery sealing chamber 31 and a second elastic recovery sealing chamber 32. The first chamber is surrounded by a flexible diaphragm (such as fluororubber or polyurethane), and its inner diameter matches the large end of the conical recovery column 41. This is used to form a gradual exhaust gap when the piston 11 enters, generating controllable back pressure and achieving smooth deceleration. The second chamber has a radially retractable elastic inner edge. When high-pressure gas (which is the exhaust gas from the cylinder body 1) is filled inside, its inner edge deforms and tightly embeds into the annular groove 42 on the surface of the conical recovery column 41, forming a physical lock.

[0026] Understandably, traditional cylinders directly discharge residual compressed air into the atmosphere at the end of the return stroke, which not only wastes energy but also generates harsh exhaust noise. Furthermore, due to the lack of effective buffering, piston 11 still oscillates after stopping, affecting repeatability. This implementation uses a dual-chamber design to convert the originally wasted exhaust energy into buffer resistance and locking force, eliminating energy waste and noise pollution while improving positioning stability.

[0027] The adaptive control loop 5 is executed by the MCU in the energy-saving control module. Its core logic is: to receive the speed signal fed back by the position detection unit 2 in real time. If it is determined that the speed of the piston 11 exceeds the preset safety threshold (such as 0.5 m / s), the initial exhaust diameter of the first elastic recovery sealing chamber 31 is reduced by adjusting the proportional valve or throttle valve in the energy-saving control module, thereby enhancing the back pressure intensity in the initial stage of buffering and preventing overspeed impact.

[0028] Regarding buffering, conventional cylinders mostly employ fixed orifice or spring-loaded buffer structures. Fixed orifices close instantaneously upon high-speed piston impact, causing a sudden surge in back pressure (the peak pressure can reach more than twice the working pressure), triggering severe impact and vibration. Spring-loaded buffers, due to their constant stiffness, cannot match the energy absorption requirements at different speeds, causing piston 11 to rebound or become unstable at its stop. Therefore, fixed buffer structure parameters cannot cope with dynamic characteristic deviations caused by load changes, fluctuations in air supply pressure, or differences in ambient temperature. For example, overshoot is prone to occur under light-load, high-speed conditions, while premature braking may occur under heavy-load, low-speed conditions, severely affecting production cycle time and positioning consistency.

[0029] To this end, the present invention also provides some embodiments in which the conical recovery column 41 has a tapered structure with a gradually changing cross-section. When it enters the first elastic recovery sealing cavity 31, the exhaust gap formed between it and the inner wall of the cavity gradually decreases as the stroke deepens, thereby generating a linearly increasing back pressure resistance to decelerate the piston 11. When the piston 11 completes its working stroke, the conical recovery column 41 gradually inserts into the first elastic recovery sealing cavity 31. As the insertion depth increases, the annular exhaust gap formed between the outer wall of the conical column and the inner wall of the elastic diaphragm continuously and uniformly decreases from an initial value (e.g., 1.5 mm) to a near-closed state (e.g., 0.1 mm). According to the principles of fluid mechanics, the flow area A of gas passing through the gradually narrowing gap decreases linearly. The back pressure resistance is related to the pressure difference and the effective area. Under a constant exhaust flow rate, the reduction of the gap leads to an increase in local flow resistance, thereby forming a back pressure in the chamber that increases approximately linearly with the depth of the stroke. This back pressure acts in the opposite direction on the end face of piston 11, generating a braking force opposite to the direction of motion, causing the piston 11 speed to decelerate smoothly from the initial 0.6–0.8 m / s to near zero, achieving soft contact or soft landing.

[0030] Based on the above, a cascaded trigger valve 33 and a second elastic recovery sealing chamber 32 with centripetal contraction characteristics are further configured to achieve a self-locking function. Specifically: In the gas passage between the first elastic recovery sealing chamber 31 and the second elastic recovery sealing chamber 32, a miniature cascaded trigger valve 33 (e.g., a pilot-operated pressure control valve or a diaphragm-type one-way normally closed valve) is integrated. This valve has a preset opening pressure threshold (preferably 0.65–0.75 MPa), and its valve core is composed of a highly sensitive elastic diaphragm and a return spring. Under normal conditions, it is in the closed state, blocking the gas passage between the two chambers.

[0031] When piston 11 enters the buffer phase, the conical recovery column 41 gradually compresses the gas in the first elastic recovery sealing chamber 31, causing the pressure inside the chamber to rise. The cascade trigger valve 33 is only activated when both conditions are met simultaneously: Position condition: Piston 11 has moved to near the end of its stroke (confirmed by position detection unit 2, error ≤ ±0.1mm). Pressure condition: When the pressure inside the first elastic recovery sealing chamber 31 reaches a preset threshold (e.g., 0.7 MPa), it indicates that the piston 11 has completed effective deceleration and stopped stably.

[0032] At this moment, the high-pressure gas pushes the diaphragm of the cascaded trigger valve 33 to overcome the spring force, and the valve port opens instantaneously, guiding the recovered high-pressure gas in the first chamber to the second elastic recovery sealing chamber 32. Understandably, if the gas in the buffer chamber is directly used for locking, locking may be triggered before the piston 11 is fully in position, leading to mis-locking or insufficient locking force; while if independent gas supply locking is used, additional piping and control signals are required, increasing system complexity and energy consumption. The locking action only begins after the piston 11 has precisely stopped.

[0033] The second elastic recovery sealing cavity 32 is integrally embedded inside the end cap, and its core feature is its centripetally contractible elastic inner edge. This inner edge is integrally molded from highly elastic polyurethane or special silicone rubber, and its initial inner diameter is slightly smaller than the diameter of the small end of the conical recovery column 41 (e.g., 0.3–0.5 mm smaller), forming a pre-tightening interference. The outer side of the cavity is fixedly connected to the rigid metal shell, while the inner side is a free deformation surface.

[0034] When the cascade trigger valve 33 opens, high-pressure gas (0.6–0.8 MPa) rapidly fills the second chamber, acting on the outer surface of the elastic inner edge. Driven by the gas pressure, the elastic inner edge contracts radially towards the center (deformation approximately 0.4–0.6 mm), its front end profile tightly fitting and embedding into the annular groove 42 on the surface of the conical recovery column 41, forming a circumferential mechanical engagement. This is because the sidewalls of the groove have a certain angle (preferably 15°–30°).

[0035] In some embodiments, a one-way recovery valve 51 and an energy storage chamber 52 are also included. The first elastic recovery sealing chamber 31 is connected to the energy storage chamber 52 through the one-way recovery valve 51. The high-pressure gas compressed during the buffering process is recovered into the energy storage chamber 52 through the one-way recovery valve 51. The intelligent processing unit 53 determines that the speed exceeds the safety threshold based on the real-time speed calculated by the position detection unit 2. If the speed exceeds the safety threshold, the intelligent processing unit 53 reduces the initial exhaust diameter by driving the proportional adjustment valve in the energy-saving control module to enhance the intervention strength of the first elastic recovery sealing chamber 31 in the initial buffering stage. Preferably, the recovered gas in the energy storage chamber 52 is connected to the working air inlet of the cylinder through a pre-charge circuit to provide auxiliary thrust at the moment the piston 11 starts. During the piston 11 retraction buffering process, the conical recovery column 41 compresses the gas in the first elastic recovery sealing chamber 31, and the pressure inside the chamber rises rapidly. When the pressure exceeds the opening threshold of the one-way recovery valve 51 (e.g., 0.35 MPa), the valve core opens, and a portion of the high-pressure gas (typically 60%–80% of the total gas in the chamber) no longer escapes into the atmosphere. Instead, it flows unidirectionally into the energy storage chamber 52 through the valve and is temporarily stored in the nitrogen bladder. Due to the check valve's check-back characteristic, the gas in the energy storage chamber 52 cannot flow back, ensuring effective energy storage.

[0036] The energy storage chamber 52 is connected to the working air inlet of the cylinder (usually the rodless chamber inlet) via a pre-charge circuit. This circuit includes a precision pressure reducing valve (set output pressure 0.4 MPa) and a normally open solenoid directional valve. During the preparation phase before piston 11 starts (100 ms before the start of the next working cycle), the control system briefly opens the solenoid valve to pre-inject the high-pressure gas recovered in the energy storage chamber 52 into the working chamber.

[0037] When the main gas supply valve opens and piston 11 begins to extend, this pre-charged gas is superimposed on the main gas source, providing additional auxiliary thrust at the moment piston 11 starts. Especially under low-pressure gas supply or high-inertia load start-up conditions, this auxiliary thrust effectively overcomes static friction and inertial resistance, improving the response lag problem.

[0038] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. An energy-saving cylinder comprising a cylinder body, an energy-saving control module and a pilot control module integrated at one end of the cylinder body, characterized in that, Also comprising: a position detection unit comprising a magnetic switch arranged on the cylinder body for sensing the speed of the piston; a locking mechanism comprising a tapered recovery column arranged at the end of the piston, the surface of the tapered recovery column being provided with an annular groove; a double-tube recovery assembly arranged in the end cover of the cylinder body, comprising a first elastic recovery sealing cavity and a second elastic recovery sealing cavity, the first elastic recovery sealing cavity being used for deceleration buffering in cooperation with the tapered recovery column, and the second elastic recovery sealing cavity being used for embedding the annular groove to achieve position locking; an adaptive control loop connected with the cylinder body, the double-tube recovery assembly and the position detection unit respectively, for dynamically adjusting the air pressure in the double-tube recovery assembly through the energy-saving control module according to the speed signal fed back by the position detection unit.

2. The energy saving cylinder according to claim 1, characterized in that: The tapered recovery column is a cross-sectionally tapered cone structure, when it enters the first elastic recovery sealing cavity, the exhaust gap formed between the tapered recovery column and the inner wall of the first elastic recovery sealing cavity gradually decreases with the deepening of the stroke, thereby generating a linearly increasing back pressure resistance to achieve piston deceleration.

3. The energy saving cylinder according to claim 2, characterized in that: The adaptive control loop comprises a one-way recovery valve and an energy storage cavity, the first elastic recovery sealing cavity is connected to the energy storage cavity through the one-way recovery valve, and the high-pressure gas compressed during the buffering process is recovered into the energy storage cavity through the one-way recovery valve.

4. The energy saving cylinder according to claim 2, wherein: A cascade trigger valve is arranged between the first elastic recovery sealing cavity and the second elastic recovery sealing cavity; when the piston moves to a predetermined position and the pressure in the first elastic recovery sealing cavity reaches a preset threshold, the cascade trigger valve is opened, guiding the recovered high-pressure gas into the second elastic recovery sealing cavity.

5. The energy saving cylinder according to claim 4, characterized in that: The second elastic recovery sealing cavity has a centripetally contractible elastic inner edge, when the inside is filled with high-pressure gas, the inner edge deforms and embeds into the annular groove on the surface of the tapered recovery column.

6. The energy saving cylinder according to claim 3, wherein: The adaptive control loop further comprises an intelligent processing unit, according to the real-time speed calculated by the position detection unit, if it is determined that the speed exceeds a safety threshold, then the initial exhaust passage is reduced by driving the proportional regulating valve in the energy-saving control module, so as to enhance the intervention intensity of the first elastic recovery sealing cavity in the initial buffering stage.

7. The energy saving cylinder according to claim 3, wherein: The recovered gas in the energy storage cavity is connected to the working inlet of the cylinder through a pre-charging loop, for providing auxiliary thrust at the moment of starting the piston.

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