Electric cylinder with spring buffer mechanism

Abstract

The utility model relates to an electric cylinder with spring buffer mechanism, including hollow cylinder, still including setting installation cylinder in hollow cylinder left end surface, the left end surface of installation cylinder is connected with mounting piece, and the inside installation of installation cylinder has motor, hollow cylinder inboard is equipped with fixed plate, and the rotation is connected with screw rod on fixed plate, and the output end of motor is connected with screw rod, and the outside screw thread connection of screw rod has hollow output rod, and the outside of hollow output rod is equipped with the limit sliding plate of sleeve, and the limit rail that cooperates with limit sliding plate is equipped in the inner wall of installation cylinder, and the limit projection that cooperates with limit rail sliding is equipped on limit sliding plate, the utility model sets up the flexible sensing spring made of conductive elastic composite material in the hollow cylinder coaxially, and forms the force loop with the upper and lower electrode ring, has the function of buffering and real -time sensing axial force or displacement, does not need external sensor, saves the space, simplifies the assembly, promotes the reliability, and supports the compliance control, enhances human -computer interaction security and intelligent level.

Description

Technical Field

[0001] This utility model relates to the technical field of electric cylinder buffer mechanism, specifically an electric cylinder with a spring buffer mechanism. Background Technology

[0002] The device is an electric linear actuator designed specifically for humanoid robot joints. Its main function is to achieve linear movement of the joints and to achieve precise position, speed and force control through integrated sensors and control modules.

[0003] In common electric cylinders with spring buffer mechanisms, in order to sense the output force or displacement, it is usually necessary to install an additional independent pressure sensor, strain gauge or force-sensitive element. These external sensing devices are often arranged at the end of the output rod, the cylinder flange or the load connection interface. However, this design approach brings a series of significant problems: First, since the internal space of the electric cylinder is already limited, especially when used in humanoid robots or compact actuators, the cylinder diameter and axial length are strictly constrained. The additional sensors and their mounting brackets, lead wire channels, and sealing structures further encroach on the valuable internal volume, limiting the size optimization of transmission components (such as lead screws and motors), thus affecting the overall thrust density and power efficiency. Second, the introduction of independent sensors significantly increases the complexity of the assembly process, requiring not only precise alignment, pre-tightening adjustment, and electric welding, but also multiple rounds of calibration and sealing, resulting in longer production cycles, lower yield rates, and higher maintenance costs. More importantly, external or semi-embedded sensors are highly susceptible to impact loads, vibration fatigue, or mechanical collisions under high dynamic conditions. For example, instantaneous overloads generated during robot falls, rebounds from grasping hard objects, or frequent start-stop cycles may cause strain gauge breakage, pressure-sensitive chip failure, or lead wire detachment, resulting in loss of force feedback signals or even control instability, seriously weakening the reliability and safety of the equipment in real unstructured environments. Therefore, traditional solutions have significant shortcomings in terms of space utilization, assembly efficiency, and shock resistance, making it difficult to meet the comprehensive requirements of the new generation of intelligent electric actuators for high integration, high reliability, and high environmental adaptability. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides an electric cylinder with a spring buffer mechanism. The flexible sensing spring integrates buffering and force measurement functions, eliminating the need for external sensors, saving space, simplifying assembly, and improving reliability and control intelligence. It solves the problems of common electric cylinders requiring external sensors, which occupy space, are difficult to assemble, are easily damaged, and cannot meet the requirements of high integration and high reliability.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an electric cylinder with a spring buffer mechanism, comprising a hollow cylinder; and a mounting cylinder disposed on the left end face of the hollow cylinder, wherein a mounting component is connected to the left end face of the mounting cylinder, a motor is installed inside the mounting cylinder, a fixing plate is provided on the inner side of the hollow cylinder, a screw is rotatably connected to the fixing plate, the output end of the motor is connected to the screw, and a hollow output rod is threadedly connected to the outer side of the screw. A limiting slide plate is fitted on the outer side of the hollow output rod. A limiting rail that mates with the limiting slide plate is provided on the inner wall of the mounting cylinder. A limiting protrusion that slides with the limiting rail is provided on the limiting slide plate. A lower electrode ring is installed in the groove of the limiting slide plate. A mounting platform is provided at the limiting step inside the hollow cylinder. An upper electrode ring is installed on the mounting platform. A flexible sensing spring made of conductive elastic composite material is provided between the upper electrode ring and the lower electrode ring. The flexible sensing spring is used to sense axial force or displacement while buffering.

[0006] Furthermore, a cover plate is fixedly installed on the right end face of the hollow cylinder, and an axially telescopic rod is connected to the right end face of the hollow output rod. The end of the telescopic rod is provided with a connector for connecting an external load.

[0007] Furthermore, the flexible sensing spring is completely housed within the hollow cylinder and arranged coaxially with the hollow output rod. Its axial compression changes with the movement of the hollow output rod, thereby altering the resistance value to enable real-time sensing of force or displacement.

[0008] Furthermore, the upper electrode ring is embedded on the mounting platform at the top of the hollow cylinder cavity and maintains electrical contact with the upper conductive layer of the flexible sensing spring, while the lower electrode ring is installed in the annular groove of the limiting slide plate and maintains electrical contact with the lower end of the flexible sensing spring.

[0009] Furthermore, the upper electrode ring and the lower electrode ring are respectively connected to the external signal acquisition circuit through flexible leads. The flexible leads are flexible printed circuit cables and are led out through the lead holes on the hollow cylinder or the limiting slide plate.

[0010] Furthermore, the limiting slide plate forms an axial guide sliding pair with the limiting protrusion on its surface and the limiting rail on the inner wall of the mounting cylinder, which is used to constrain the hollow output rod from circumferential rotation during movement.

[0011] Furthermore, the flexible sensing spring is composed of a thermoplastic polyurethane matrix and carbon nanotube filler. Its resistance changes monotonically with compression deformation, which can be used to construct a force-electric signal mapping model for closed-loop compliant control.

[0012] Compared with the prior art, the technical solution of this application has the following beneficial effects: 1. By coaxially setting a flexible sensing spring made of conductive elastic composite material inside the hollow cylinder and using upper and lower electrode rings to form a resistance measurement circuit, the spring can be used directly as a force / displacement sensor while performing buffering and energy storage functions. There is no need to install an additional independent pressure or strain sensor, which not only saves internal space and reduces assembly complexity, but also avoids the problem of traditional external sensors being easily damaged by impact. This greatly improves the structural compactness, environmental adaptability and long-term operational reliability of the electric cylinder under high dynamic and high impact conditions. 2. The resistance of the flexible sensing spring changes monotonically with the compression deformation caused by the movement of the hollow output rod. Combined with the external signal acquisition circuit, the axial force or displacement can be calculated in real time. This feedback signal can be directly used in closed-loop control algorithms (such as impedance control or force-position hybrid control), enabling the electric cylinder to have adaptive compliant response capability when driving robot joints or performing grasping tasks. This effectively absorbs external impacts, prevents overload damage, and improves the safety and intelligence level when interacting with humans or unstructured environments. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a cross-sectional three-dimensional structural diagram of the present invention; Figure 3 This is a partial cross-sectional perspective view of the three-dimensional structure of this utility model; Figure 4 This is a three-dimensional structural diagram of the hollow output rod location of this utility model; Figure 5 This is a three-dimensional structural diagram of the location of the limiting rail of this utility model.

[0014] In the diagram: 1. Hollow cylinder; 2. Mounting cylinder; 3. Mounting component; 31. Motor; 4. Fixing plate; 5. Screw; 6. Limiting slide plate; 7. Lower electrode ring; 8. Mounting platform; 9. Upper electrode ring; 10. Flexible sensing spring; 11. Hollow output rod; 12. Limiting protrusion; 13. Limiting rail; 14. Cover plate; 15. Telescopic rod; 16. Connecting component. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0016] Please see Figures 1-5An electric cylinder with a spring buffer mechanism in this embodiment includes a hollow cylinder 1; it also includes a mounting cylinder 2 disposed on the left end face of the hollow cylinder 1, a mounting component 3 connected to the left end face of the mounting cylinder 2, a motor 31 installed inside the mounting cylinder 2, a fixing plate 4 disposed on the inner side of the hollow cylinder 1, a screw 5 rotatably connected to the fixing plate 4, the output end of the motor 31 connected to the screw 5, and a hollow output rod 11 threadedly connected to the outer side of the screw 5.

[0017] In this embodiment, a flexible sensing spring 10 made of conductive elastic composite material is coaxially arranged inside the hollow cylinder 1, and a resistance measurement circuit is formed with the upper and lower electrode rings 7. The spring can directly sense axial force or displacement while realizing buffering and energy storage functions. No additional sensors are required, saving space, simplifying assembly, improving reliability, and providing real-time feedback signals for compliant closed-loop control, thereby enhancing the safety and intelligence level of the electric cylinder in human-machine interaction or high-impact scenarios.

[0018] Please see Figures 1-5 In this embodiment, in order to make the spring conductive and place it inside the cylinder as a sensor, it can both buffer and measure force, saving space, reducing parts, and making it less prone to damage. In this embodiment, the hollow output rod 11 is fitted with a limiting slide plate 6 on the outside, and the inner wall of the mounting cylinder 2 is provided with a limiting rail 13 that cooperates with the limiting slide plate 6. The limiting slide plate 6 is provided with a limiting protrusion 12 that slides with the limiting rail 13. The lower electrode ring 7 is installed in the groove of the limiting slide plate 6. The limiting step inside the hollow cylinder 1 is provided with a mounting platform 8, and the upper electrode ring 9 is installed on the mounting platform 8. A flexible sensing spring 10 made of conductive elastic composite material is provided between the upper electrode ring 9 and the lower electrode ring 7. The flexible sensing spring 10 is used to sense axial force or displacement while buffering.

[0019] In this embodiment, a flexible sensing spring 10 made of conductive elastic composite material is used. The resistance of the spring changes when it is compressed and deformed, thereby sensing axial force or displacement. This eliminates the need for additional sensors, saves internal space, reduces the number of parts, and improves impact resistance and long-term reliability. The limiting slide plate 6 slides with the limiting protrusion 12 on it and the limiting rail 13 on the inner wall of the mounting cylinder 2, effectively constraining the circumferential rotation of the hollow output rod 11 and ensuring its smooth and reliable movement. The lower electrode ring 7 is located in the groove of the limiting slide plate 6, and the upper electrode ring 9 is fixed on the mounting platform 8 inside the hollow cylinder 1. Both of them maintain good electrical contact with the two ends of the flexible sensing spring 10, forming a stable resistance measurement circuit. This provides a reliable electrical signal for real-time acquisition of force or displacement information, thereby supporting compliant control and safe human-machine interaction.

[0020] It should be noted that a cover plate 14 is fixedly installed on the right end face of the hollow cylinder 1, and an axially telescopic rod 15 is connected to the right end face of the hollow output rod 11. The end of the telescopic rod 15 is provided with a connector 16 for connecting to an external load. The cover plate 14 at the right end of the hollow cylinder 1 is used to seal the internal structure to prevent dust or foreign objects from entering, while enhancing the overall rigidity and sealing. The hollow output rod 11 is connected to the telescopic rod 15, which allows the output motion to be extended to meet the needs of a larger stroke. The connector 16 at the end of the telescopic rod 15 is used to directly connect to an external load, which facilitates quick installation or replacement of the actuator end, improves assembly flexibility and applicability, and the overall structure is compact with efficient and reliable motion transmission.

[0021] Please see Figures 1-5 In this embodiment, to ensure that the resistance of the flexible sensing spring 10 changes when compressed, allowing for the calculation of force or position for intelligent control and making the robot's movements smoother and safer, the flexible sensing spring 10 is completely housed within the inner cavity of the hollow cylinder 1 and coaxially arranged with the hollow output rod 11. Its axial compression changes with the movement of the hollow output rod 11, thereby altering the resistance value for real-time sensing of force or displacement. The upper electrode ring 9 is embedded in the mounting platform 8 at the top of the inner cavity of the hollow cylinder 1 and is aligned with the upper end of the flexible sensing spring 10. The conductive layer maintains electrical contact. The lower electrode ring 7 is installed in the annular groove of the limiting slide plate 6 and maintains electrical contact with the lower end of the flexible sensing spring 10. The upper electrode ring 9 and the lower electrode ring 7 are respectively connected to the external signal acquisition circuit through flexible leads. The flexible leads are flexible printed circuit cables and are led out through the lead holes on the hollow cylinder 1 or the limiting slide plate 6. The flexible sensing spring 10 is composed of thermoplastic polyurethane matrix and carbon nanotube filler. Its resistance changes monotonically with compression deformation and can be used to construct a force-electric signal mapping model for closed-loop compliant control.

[0022] In this embodiment, the flexible sensing spring 10 is composed of a thermoplastic polyurethane matrix and carbon nanotube filler. Its resistance changes monotonically with compression deformation, which can convert mechanical deformation into electrical signals for real-time force or displacement sensing, providing a basis for compliant control. The upper electrode ring 9 and the lower electrode ring 7 maintain electrical contact with the two ends of the flexible sensing spring 10, forming a stable measurement circuit to ensure accurate and reliable signal acquisition. The flexible lead wire adopts a flexible printed circuit board to connect the electrode ring and the external signal processing unit, which has good bending durability, adapts to reciprocating motion and is not easy to break. The entire sensing structure is integrated inside the hollow cylinder 1, eliminating the need for external sensors, saving space, simplifying assembly, and maintaining high reliability under high dynamic or impact conditions, making the robot's actions smoother and the interaction safer.

[0023] It should be noted that the limiting slide plate 6 forms an axial guide sliding pair with the limiting protrusion 12 on its surface and the limiting rail 13 on the inner wall of the mounting cylinder 2, which is used to constrain the hollow output rod 11 from rotating circumferentially during the movement. The fixing plate 4 is provided with a shaft hole, and the screw 5 passes through the shaft hole and can rotate relative to it.

[0024] The working principle of the above embodiments is as follows: In use, motor 31 starts and drives screw 5 to rotate. Screw 5 drives hollow output rod 11 to move linearly along the axial direction through threaded transmission. During the movement, hollow output rod 11 pushes or pulls the external load, and at the same time drives the limit slide plate 6 linked with it to move synchronously. The limit protrusion 12 on the limit slide plate 6 slides along the limit rail 13 on the inner wall of the mounting cylinder 2 to form an axial guide pair, which effectively prevents the hollow output rod 11 from rotating circumferentially during the movement, ensuring smooth and accurate output action. As the hollow output rod 11 moves axially, the flexible sensing spring 10 arranged coaxially inside it is compressed or released. The spring is made of thermoplastic polyurethane matrix and carbon nanotube filler. When compressed, the resistance value changes monotonically. The upper electrode ring 9 and the lower electrode ring 7 are respectively close to the two ends of the spring and maintain stable electrical contact, forming a complete The resistance measurement circuit outputs electrical signals to an external signal acquisition unit via flexible printed circuit wiring, reflecting the current axial force or displacement in real time. This feedback information is used to achieve compliant closed-loop control, enabling the electric cylinder to automatically adjust its output stiffness and torque when encountering external impacts or human interaction, resulting in smoother and safer operation. The entire sensing and buffering structure is fully integrated into the inner cavity of the hollow cylinder 1, eliminating the need for additional independent sensors, saving space, reducing the number of parts, and improving impact resistance and long-term operational reliability. Meanwhile, the cover plate 14 at the right end of the hollow cylinder 1 seals the internal components, preventing dust and foreign objects from entering and enhancing overall rigidity. The telescopic rod 15 connected to the hollow output rod 11 transmits motion to the end connector 16, facilitating quick docking with different loads and adapting to various application scenarios. The overall structure is compact, responsive, and intelligently controlled.

[0025] It should be noted that the transmission connection between the screw 5 and the hollow output rod 11 can adopt a high-load-bearing threaded pair structure, including but not limited to trapezoidal screws, ball screws, or planetary roller screws; among them, the planetary roller screw structure is preferred, which has advantages such as multi-point line contact, high rigidity, large thrust and long service life, and is especially suitable for high dynamic load scenarios such as humanoid robot joints. When using a planetary roller screw, the screw 5 can be used as the main shaft and the hollow output rod 11 can be used as the nut, or a reverse layout can be adopted so that the hollow output rod 11 can be used as the main shaft to achieve linear output. All of these are equivalent embodiments of this utility model.

[0026] It should be noted that the resistance signal output by the flexible sensing spring 10 can be read by an external acquisition device to achieve compliant control. This control logic is a conventional application in the field and does not affect the novelty and practicality of the structure of this utility model.

[0027] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0028] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An electric cylinder with a spring buffer mechanism, comprising a hollow cylinder (1); characterized in that: It also includes an installation cylinder (2) set on the left end face of the hollow cylinder (1), an installation part (3) connected to the left end face of the installation cylinder (2), a motor (31) installed inside the installation cylinder (2), a fixing plate (4) provided on the inner side of the hollow cylinder (1), a screw (5) rotatably connected to the fixing plate (4), the output end of the motor (31) connected to the screw (5), and a hollow output rod (11) threadedly connected to the outside of the screw (5). A limiting slide plate (6) is sleeved on the outside of the hollow output rod (11). A limiting rail (13) that cooperates with the limiting slide plate (6) is provided on the inner wall of the mounting cylinder (2). A limiting protrusion (12) that slides with the limiting rail (13) is provided on the limiting slide plate (6). A lower electrode ring (7) is installed in the groove of the limiting slide plate (6). An mounting platform (8) is provided at the limiting step inside the hollow cylinder (1). An upper electrode ring (9) is installed on the mounting platform (8). A flexible sensing spring (10) made of conductive elastic composite material is provided between the upper electrode ring (9) and the lower electrode ring (7). The flexible sensing spring (10) is used to sense axial force or displacement while buffering.

2. An electric cylinder with a spring buffer mechanism according to claim 1, characterized in that: A cover plate (14) is fixedly installed on the right end face of the hollow cylinder (1), and an axially telescopic rod (15) is connected to the right end face of the hollow output rod (11). The end of the telescopic rod (15) is provided with a connector (16) for connecting external loads.

3. An electric cylinder with a spring buffer mechanism according to claim 1, characterized in that: The flexible sensing spring (10) is completely housed in the inner cavity of the hollow cylinder (1) and is arranged coaxially with the hollow output rod (11). Its axial compression changes with the movement of the hollow output rod (11), thereby changing the resistance value to sense force or displacement in real time.

4. An electric cylinder with a spring buffer mechanism according to claim 1, characterized in that: The upper electrode ring (9) is embedded on the mounting platform (8) at the top of the inner cavity of the hollow cylinder (1) and maintains electrical contact with the upper conductive layer of the flexible sensing spring (10). The lower electrode ring (7) is installed in the annular groove of the limiting slide plate (6) and maintains electrical contact with the lower end of the flexible sensing spring (10).

5. An electric cylinder with a spring buffer mechanism according to claim 1, characterized in that: The upper electrode ring (9) and the lower electrode ring (7) are respectively connected to the external signal acquisition circuit through flexible leads. The flexible leads are flexible printed circuit cables and are led out through the lead holes on the hollow cylinder (1) or the limiting slide plate (6).

6. An electric cylinder with a spring buffer mechanism according to claim 1, characterized in that: The limiting slide plate (6) forms an axial guide sliding pair with the limiting protrusion (12) on its surface and the limiting rail (13) on the inner wall of the mounting cylinder (2), which is used to constrain the hollow output rod (11) from rotating circumferentially during the movement.

7. An electric cylinder with a spring buffer mechanism according to claim 1, characterized in that: The flexible sensing spring (10) is composed of thermoplastic polyurethane matrix and carbon nanotube filler. Its resistance changes monotonically with compression deformation and can be used to construct a force-electric signal mapping model for closed-loop compliant control.

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