Linear actuator with power-off self-locking and constant supporting force

Abstract

The invention relates to a linear actuator with power-off self-locking and constant supporting force. The linear actuator comprises a driving assembly, a gas spring unit, a braking assembly and a planetary roller lead screw pair. The driving assembly converts electric energy into rotating kinetic energy to drive the actuator to operate. The air spring unit provides constant supporting force through a built-in high-pressure air cavity, and the pressure is adjusted through an inflation valve so as to dynamically adjust the supporting force. The braking assembly realizes power-off self-locking through a movable permanent magnet and a liquid sealing structure; the planetary roller lead screw pair converts rotation kinetic energy of the driving assembly into linear motion. The technical problems that an existing linear actuator is high in energy consumption, unstable in supporting force and lack of a self-locking function are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of automation equipment and humanoid robots, and specifically relates to a linear actuator with power-off self-locking and constant supporting force. Background Art

[0002] Linear actuators are widely used in automation equipment and mobile robots, and are mainly responsible for achieving precise linear motion and force transmission. However, existing linear actuators have shortcomings in energy efficiency management, which affects the endurance and operating efficiency of mobile robots. Existing designs usually rely on the drive components to continuously output high power, which not only increases energy consumption but also affects dynamic response and stability. In addition, the support force is unstable when the load changes, resulting in energy waste, and the traditional actuator lacks a self-locking function, which may pose a safety hazard.

[0003] The present invention combines gas springs and planetary roller screws to innovatively construct an efficient energy management system. The gas spring provides constant support force, reduces the power demand of the drive components, and improves energy utilization efficiency; the planetary roller screw ensures precise motion control and improves dynamic response and stability under load. The addition of a power-off self-locking module can quickly lock the position when the power is off, prevent energy waste, and improve safety. This design breaks through the technical bottleneck of traditional linear actuators and significantly improves the robot's endurance and work efficiency. Summary of the invention

[0004] The present invention provides a linear actuator with power-off self-locking and constant supporting force, which includes: a drive component, used to convert electrical energy into rotational kinetic energy to drive the actuator to operate; a gas spring unit, including an inflation valve and a movable plug, providing a constant supporting force through a built-in high-pressure gas chamber, and adjusting the gas pressure through the inflation valve to adjust the supporting force; a brake component, including a moving permanent magnet, a coil, a spring and an opening and closing rod, used to achieve a self-locking function through a liquid sealing structure when power is off to ensure that the output end position is maintained; a planetary roller screw pair, including a planetary roller screw nut, a center screw, a planetary screw and a retaining frame, used to convert the rotational kinetic energy of the drive component into linear motion.

[0005] As described above, a linear actuator with power-off self-locking and constant supporting force, the driving assembly includes: a rear end cover, a front end cover and a linear actuator housing, which are sealed by sealing rings 1 and 2; a motor stator and a multi-stage magnetic ring, the motor stator drives the multi-stage magnetic ring to rotate; a deep groove ball bearing and a four-point contact ball bearing, respectively providing support and stability for the rotation of the multi-stage magnetic ring; a wave-shaped gasket, which compensates for the axial clearance of the deep groove ball bearing through its elastic characteristics.

[0006] As described above, a linear actuator with power-off self-locking and constant supporting force, the planetary roller screw pair includes: a planetary roller screw nut, a center screw and a planetary screw; the planetary roller screw nut is fixedly connected to the multi-stage magnetic ring and moves with the multi-stage magnetic ring; the center screw has a high-precision smooth inner hole, which is used as a high-pressure chamber of the gas spring.

[0007] As described above, a linear actuator with power-off self-locking and constant supporting force, the gas spring unit includes: an inflation valve and a movable plug, which are arranged in the inner hole of the central screw to form a high-pressure air chamber; the high-pressure air chamber is filled with high-pressure nitrogen, and the gas pressure is adjusted by the inflation valve to dynamically adjust the supporting force; the movable plug moves axially along the central screw as the pressure in the high-pressure air chamber changes, so as to adjust the direction and range of the supporting force.

[0008] As described above, a linear actuator with power-off self-locking and constant supporting force, the brake assembly includes: a moving permanent magnet, a coil and a spring. When the coil is energized, the moving permanent magnet is attracted to put the opening and closing rod in the open position, and when the power is off, the spring puts the opening and closing rod in the closed position; the A cavity and the B cavity are respectively located on both sides of the inner hole of the center screw, and the opening and closing of the opening and closing rod are used to control whether the liquid can flow, and then control whether the center screw can move axially, thereby realizing the power-off self-locking function.

[0009] As described above, a linear actuator with power-off self-locking and constant supporting force, the driving assembly includes a rear end cover, a sealing ring 1, a wave-shaped gasket, a deep groove ball bearing, a linear actuator housing, a motor stator, a multi-stage magnetic ring, a four-point contact ball bearing, a sealing ring 2 and a front end cover, and motion output is achieved through the coordinated work of the motor stator and the multi-stage magnetic ring.

[0010] In the linear actuator with power-off self-locking and constant supporting force as described above, the elastic characteristics of the wave-shaped gasket are used to compensate for the axial clearance of the deep groove ball bearing, thereby eliminating the axial clearance of the linear actuator.

[0011] In the linear actuator with power-off self-locking and constant supporting force as described above, the gas spring unit includes an inflation valve and a movable plug, and the pressure in the high-pressure gas chamber is adjusted by the inflation valve to adjust the supporting force.

[0012] In the linear actuator with power-off self-locking and constant supporting force as described above, the high-pressure gas chamber prevents leakage of high-pressure nitrogen through a sealing structure to ensure long-term stable operation of the gas spring unit.

[0013] As described above, a linear actuator with power-off self-locking and constant supporting force, the brake assembly includes a coil, a moving permanent magnet and a spring. When the coil is powered off, the moving permanent magnet is attracted to the fixed permanent magnet under the action of the spring to achieve the power-off self-locking function.

[0014] As described above, in a linear actuator with power-off self-locking and constant supporting force, the inner hole of the center screw is divided into chamber A and chamber B. Chamber A and chamber B realize fluid control through the linkage of the piston rod and the opening and closing rod, thereby controlling the movement state of the center screw.

[0015] As described above, a linear actuator with power-off self-locking and constant supporting force, the encoder assembly includes a code disc mounting seat, an encoder code disc and an encoder reader, which are used to record and feedback the motion position information of the actuator in real time to achieve precise control.

[0016] In the linear actuator with power-off self-locking and constant supporting force as described above, the encoder disc is fixedly connected to the lead screw nut, and when the lead screw nut rotates, the encoder disc rotates synchronously, thereby transmitting position information.

[0017] Based on the above technical scheme, the linear actuator with power-off self-locking and constant supporting force of the present invention converts electrical energy into rotational kinetic energy through a driving component, converts rotational kinetic energy into linear motion through a planetary roller screw pair, and uses a gas spring unit to provide a constant supporting force, and realizes the power-off self-locking function through a brake component, thereby effectively solving the problems of insufficient supporting force and unreliable self-locking function after power failure of existing linear actuators, and improving the stability and safety of the equipment. Beneficial Effects

[0018] The invention significantly improves the performance, reliability and adaptability of the actuator through innovative multi-module integrated design. Multi-stage magnetic rings and high-precision bearings are used to ensure smooth rotation and efficient energy transfer; the planetary roller screw pair realizes efficient linear motion conversion, provides high transmission efficiency and precise positioning. The gas spring unit provides constant support force, balances the load and is adjustable, enhancing system stability. The brake assembly achieves power-off self-locking through the cooperation of permanent magnets and springs, improving safety.

[0019] The module of the present invention has high integration, small size and compact structure, which optimizes energy efficiency and significantly reduces energy consumption. The innovative power-off self-locking design prevents the device from shifting position, improving safety and system stability. The overall design provides an efficient, reliable, safe and energy-saving linear drive solution in mobile robots. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of the linear actuator.

[0021] Figure 2 This is a schematic diagram of the planetary roller screw pair structure.

[0022] Figure 3 It is a schematic diagram of the structure of the gas spring unit and the brake assembly.

[0023] Figure 4 It is a schematic diagram of the inflation valve structure.

[0024] Figure 5 This is a schematic diagram of the encoder component structure.

[0025] In the figure: 1. Joint bearing 1; 2. Tension and compression sensor; 3. Rear cover; 4. Seal ring 1; 5. Wave gasket; 6. Deep groove ball bearing; 7. Linear actuator housing; 8. Drive assembly; 8.1. Motor stator; 9. Multi-stage magnetic ring; 10. Four-point contact ball bearing; 11. Seal ring 2; 12. Front cover; 13. Bushing; 14. Y-type seal ring 1; 15. Nut; 16. Joint bearing 2; 17. Gas spring unit; 17.1, inflation valve; 17.11, valve housing; 17.12, density ring six; 17.13, density ring seven; 17.14, spring two; 17.15, mandrel; 17.16, fixed shaft; 17.17, retaining ring; 17.18, sealing nail; 17.19, spring three; 17.20, adjusting screw; 17.21, external inflation tube; 18, movable plug; 19, sealing ring three; 20 , round nut; 21, brake assembly; 21.1, moving permanent magnet; 21.2, coil; 21.3, spring; 21.4, coil seat; 21.5, guide ring 1; 21.6, piston rod; 21.7, opening and closing rod; 21.8, guide ring 2; 21.9, sealing ring 4; 21.10, snap ring; 21.11, fixed piston; 21.12, density ring 5; 21.13, conical sealing ring; 21.1 4. Oil guide hole; 21.15. Fixed permanent magnet; 21.16. A cavity; 21.17. B cavity; 22. Planetary roller screw pair; 22.1. Planetary roller screw nut; 22.2. Center screw; 22.3. Planetary screw; 22.4. Cage; 23. Sealing end cover; 24. Y-type sealing ring 2; 25. Code disk mounting seat; 26. Encoder code disk; 27. Encoder reader; 28. Encoder assembly; DETAILED DESCRIPTION

[0026] This implementation is open to the public Figure 1 The linear actuator with power-off self-locking and constant supporting force shown in the figure includes the following components: a driving component 8, which is used to convert electrical energy into rotational kinetic energy to drive the actuator to operate; a gas spring unit 17, which is composed of an inflation valve 17.1 and a movable plug 18, provides a constant supporting force through a built-in high-pressure gas chamber, and adjusts the gas pressure through the inflation valve to adjust the supporting force; a brake component 21, which includes a moving permanent magnet 21.1, a coil 21.2, a spring 21.3 and an opening and closing rod 21.7, realizes a self-locking function through a liquid sealing structure when the power is off to ensure that the output end position is maintained; a planetary roller screw pair 22, which is composed of a planetary roller screw nut 22.1, a center screw 22.2, a planetary screw 22.3 and a retaining frame 22.4, converts the rotational kinetic energy of the driving component 8 into linear motion.

[0027] like Figure 1 , Figure 2 , Figure 3 The working principle is shown as follows: the driving assembly 8 drives the multi-stage magnetic ring 9 to rotate through the motor stator 8.1. The multi-stage magnetic ring 9 drives the planetary roller screw pair 22 through its fixed planetary roller screw nut 22.1 to realize the conversion of rotational motion to linear motion. The gas spring unit 17 uses the high-pressure air cavity in the center screw 22.2 to provide a constant support force, and adjusts the pressure through the inflation valve 17.1 to adapt to different load requirements. The brake assembly 21 controls the opening and closing state of the opening and closing rod 21.7 through the coil 21.2 and the spring 21.3. When the power is off, the self-locking function is realized through the fluid isolation of the A cavity 21.16 and the B cavity 21.17 to ensure the stable position.

[0028] The linear actuator with power-off self-locking and constant support force in this embodiment has the following beneficial effects: The linear actuator significantly improves the performance and reliability of the system by integrating a number of innovative designs. In terms of performance, the efficient power transmission structure and multi-thread design of the planetary roller screw pair achieve high-precision and high-efficiency power conversion. Combined with the real-time monitoring and feedback of the encoder component, the positioning accuracy and work efficiency are greatly improved. At the same time, the gas spring unit provides a constant support force, reduces the power demand of the drive component, and improves energy utilization efficiency. From a cost perspective, the system simplifies the structural design by integrating multiple functional components, reducing production and maintenance costs. In terms of safety, the brake component is designed with a power-off self-locking function. Through the control of the hydraulic circuit, the output end can be quickly locked in the event of a power outage or emergency to ensure the safety of the equipment. At the same time, the use of environmentally friendly high-pressure nitrogen as a power source, combined with a strict sealing design, reduces environmental pollution and energy waste, and demonstrates the environmental protection characteristics of the system. In addition, it can quickly lock the position when the power is off, prevent energy waste, and improve safety. This design breaks through the technical bottleneck of traditional linear actuators and significantly improves the robot's endurance and work efficiency.

[0029] This implementation is open to the public Figure 1 The driving assembly 8 of a linear actuator with power-off self-locking and constant supporting force shown in the figure includes a rear end cover 3, a sealing ring 1 4, a wave-shaped gasket 5, a deep groove ball bearing 6, a linear actuator housing 7, a motor stator 8.1, a multi-stage magnetic ring 9, a four-point contact ball bearing 10, a sealing ring 2 11 and a front end cover 12. The motion output is achieved through the coordinated work of the motor stator 8.1 and the multi-stage magnetic ring 9.

[0030] like Figure 1 The working principle shown is that the motor stator 8.1 drives the multi-stage magnetic ring 9 to rotate, and the rotation of the multi-stage magnetic ring 9 is supported and stabilized by the deep groove ball bearing 6 and the four-point contact ball bearing 10. The wave-shaped gasket 5 eliminates the axial clearance of the deep groove ball bearing 6 through its elastic characteristics, thereby maintaining the precise fit of the components and stable motion output.

[0031] The drive assembly 8 is simple in design, and the sealing ring 1 4 and the sealing ring 2 11 ensure excellent sealing performance and adaptability to harsh environments; the corrugated gasket 5 effectively compensates for the axial clearance and reduces vibration and noise; the optimized design of the multi-stage magnetic ring 9 improves the driving force output of the motor and ensures precise and stable movement.

[0032] This implementation is open to the public Figure 1 The elastic properties of the wave-shaped gasket 5 are used to compensate for the axial clearance of the deep groove ball bearing 6, thereby eliminating the axial clearance of the linear actuator.

[0033] Working Principle The wave-shaped gasket 5 is set at the installation position of the deep groove ball bearing 6, and applies axial preload to the bearing through its own elastic characteristics. When the component is loaded or running, the wave-shaped gasket 5 can automatically compensate for the axial clearance of the bearing, thereby ensuring the tight fit of the internal parts of the linear actuator and avoiding vibration or deviation caused by axial movement.

[0034] Beneficial effects: The axial clearance of the deep groove ball bearing 6 is eliminated, making the actuator run more smoothly and accurately; the mechanical noise and vibration during movement are reduced, and the overall reliability of the equipment is improved; the wave-shaped gasket 5 has the characteristics of simple structure and easy installation, and can maintain effective performance in a variety of operating environments.

[0035] This implementation is open to the public Figure 3 The gas spring unit 17 shown comprises a gas filling valve 17.1 and a movable plug 18. The pressure in the high-pressure gas chamber is adjusted by the gas filling valve 17.1 to adjust the supporting force.

[0036] Working Principle The high-pressure air cavity of the gas spring unit 17 is filled with high-pressure gas (such as nitrogen) through the charging valve 17.1, and the movable plug 18 generates axial thrust under the action of the air cavity pressure. By adjusting the opening or closing state of the charging valve 17.1, the gas pressure in the air cavity is changed, thereby adjusting the supporting force to meet the needs of different load conditions.

[0037] Beneficial Effects A stable supporting force is provided through the high-pressure air cavity, ensuring the smooth operation of the actuator under different load conditions; the supporting force can be adjusted by simply adjusting the inflation valve 17.1 to improve the flexibility of use.

[0038] This implementation is open to the public Figure 3 The high-pressure gas chamber shown in the figure prevents leakage of high-pressure nitrogen through a sealing structure to ensure long-term stable operation of the gas spring unit 17. Figure 3The high-pressure gas chamber shown forms a sealing structure through the precise cooperation of the movable plug 18, the central screw 22.2 and the density ring 5 21.12. The inflation valve 17.1 has a reliable non-return function to prevent gas from leaking in reverse. The overall sealing structure effectively prevents leakage of high-pressure nitrogen and ensures the stability of the supporting force of the gas spring unit 17 during long-term operation.

[0039] Beneficial Effects The optimized sealing structure greatly reduces the risk of gas leakage and improves the long-term reliability of the system; reduces the pressure loss caused by leakage and extends the maintenance cycle of the equipment; and the efficient sealing improves the adaptability of the gas spring unit 17 under harsh working conditions. Replaceable or deformable implementation: The sealing material can be selected from high-temperature resistant fluororubber or silicone to adapt to extreme environmental applications; the matching clearance between the central screw 22.2 and the active plug 18 can be further reduced by optimizing the processing accuracy; the non-return function of the inflation valve 17.1 can be enhanced by adding a multiple sealing ring structure.

[0040] This implementation is open to the public Figure 3 The brake assembly 21 shown includes a coil 21.2, a moving permanent magnet 21.1 and a spring 21.3. When the coil 21.2 is powered off, the moving permanent magnet 21.1 is attracted to the fixed permanent magnet 21.15 under the action of the spring 21.3, thus realizing the power-off self-locking function.

[0041] Working Principle The brake assembly 21 controls the movement of the moving permanent magnet 21.1 by energizing and de-energizing the coil 21.2. When the coil 21.2 is energized, the electromagnetic force overcomes the restoring force of the spring 21.3, so that the moving permanent magnet 21.1 is in a non-attracted state, the opening and closing rod 21.7 is opened, allowing the liquid to flow between the A cavity and the B cavity, and the center lead screw 22.2 can move freely. When the power is off, the spring 21.3 pushes the moving permanent magnet 21.1 to the attracted position, the opening and closing rod 21.7 is closed, the liquid cannot flow, and the axial movement of the center lead screw 22.2 is locked, realizing the power-off self-locking function.

[0042] The self-locking function in the case of power failure is realized to ensure the stability and safety of the system position; the brake assembly 21 has a compact structure and a quick response, which improves the control accuracy and reliability of the actuator.

[0043] Replaceable or deformable implementation method: The material of the moving permanent magnet 21.1 can be replaced with a permanent magnetic material with a higher magnetic energy product to enhance the attraction force; the stiffness of the spring 21.3 can be adjusted according to different working conditions to optimize the response time; the coil 21.2 can use a high temperature resistant coil to improve the stability of use in a high temperature environment.

[0044] This implementation is open to the public Figure 3The inner hole of the central lead screw 22.2 is divided into chamber A and chamber B. The chamber A and chamber B realize fluid control through the linkage of the piston rod 21.6 and the opening and closing rod 21.7, thereby controlling the movement state of the central lead screw 22.2.

[0045] Working Principle The inner hole of the central lead screw 22.2 is divided into chamber A and chamber B, and the flow of liquid between the two chambers is controlled by the opening and closing of the opening and closing rod 21.7. When the opening and closing rod 21.7 is opened, the liquid can flow freely between chamber A and chamber B, and the central lead screw 22.2 can move freely under the support force provided by the gas spring unit 17 and the drive of the machine drive assembly. When the opening and closing rod 21.7 is closed, the liquid is confined in chamber A or chamber B, and the central lead screw 22.2 is locked to achieve the position holding function.

[0046] Beneficial Effects The liquid control system responds quickly and cooperates with the opening and closing rod 21.7 to provide precise screw motion control; the separation structure of chamber A and chamber B improves the dynamic response performance and locking stability of the actuator; the overall design prevents position displacement under external force, thereby improving safety and reliability.

[0047] Replaceable or deformable implementation scheme: The liquid in chamber A and chamber B can be replaced with low-temperature hydraulic oil or high-viscosity liquid according to different temperature requirements; the piston rod 21.6 can be added with a wear-resistant coating to extend the service life;

[0048] This implementation is open to the public Figure 5 The encoder assembly shown includes a code disc mounting seat 25, an encoder code disc 26 and an encoder reader 27, which are used to record and feed back the motion position information of the actuator in real time to achieve precise control.

[0049] The encoder disc 26 is fixedly connected to the lead screw nut 22.1 through the disc mounting seat 25. When the lead screw nut 22.1 rotates with the movement of the central lead screw 22.2, the encoder disc 26 also rotates synchronously. The encoder reader 27 reads the movement information of the disc 26 in real time and feeds back the position signal to the control system, thereby realizing precise control and real-time monitoring of the actuator movement position.

[0050] Beneficial Effects: Real-time recording of motion position information enables precise dynamic control; the encoder component is compactly designed to adapt to high-load and high-precision working conditions; it provides fast-response position signal feedback, improving the stability and reliability of the control system.

[0051] Replaceable or modified implementation scheme The encoder code disc 26 can be replaced with a grating encoder to improve accuracy; the code disc mounting seat 25 can use a shock-absorbing design to reduce the interference of vibration during movement on signal reading.

[0052] This implementation is open to the public Figure 5The encoder disc 26 is fixedly connected to the screw nut 22.1. When the screw nut 22.1 rotates, the encoder disc 26 rotates synchronously, thereby transmitting position information.

[0053] The encoder disc 26 is fixed on the lead screw nut 22.1, and the rotation of the lead screw nut drives the code disc 26 to move synchronously. The encoder reader 27 reads the rotation of the code disc 26 and transmits the collected position information to the actuator control system to further achieve precise control. The fixed connection design of the encoder disc 26 and the lead screw nut 22.1 ensures the accuracy of signal transmission; the precise position feedback mechanism effectively improves the sensitivity of the control system; the structural design is simple and efficient, and easy to maintain and install.

[0054] Replaceable or deformable implementation method: The encoder code disk 26 can be changed to a linear encoder that directly measures linear displacement to simplify the transmission structure; the fixing method can adopt threaded connection or adhesive method to improve installation flexibility; if used in a strong magnetic field environment, non-magnetic materials or shielding structures can be used to protect the encoder code disk and reader.

[0055] This implementation is open to the public Figure 3 and Figure 4 As shown, the inflation valve 17.1 is mainly composed of the following components: an air valve housing 17.11: the main structure of the inflation valve, used to accommodate and protect the internal components; density ring six 17.12 and density ring seven 17.13: used to provide sealing effects during inflation and high-pressure gas sealing, respectively; spring two 17.14: used to provide reset elastic force when the external inflation tube is inserted and pulled out; core shaft 17.15: a key component that moves during inflation to open or close the gas channel; fixed shaft 17.16: used to stabilize the position of the core shaft and spring two to ensure their normal operation; retaining spring 17.17: used to fix and limit the movement range of the components in the air valve housing; sealing pin 17.18: a component that is pushed by high-pressure gas to open the exhaust channel when overpressure occurs; spring three 17.19: used to adjust the pressure threshold for opening the sealing pin; adjusting screw 17.20: used to adjust the compression degree of spring three, thereby setting the pressure value for opening the valve; external inflation tube 17.21: a connecting component for inflating the high-pressure gas cavity

[0056] Working principle: During the inflation process, when the external inflation tube 17.21 is inserted into the inflation hole, the spring 17.14 is compressed, and the core shaft 17.15 is pushed away to form a channel for gas circulation; the external inflation tube 17.21 and the density ring 17.12 form a seal to isolate the high-pressure gas cavity from the external environment; the high-pressure gas flows to the high-pressure gas cavity through the channel in the valve housing 17.11, completing the inflation process.

[0057] Sealing and isolation: When the external inflation tube 17.21 is pulled out of the inflation hole, the spring 17.14 is reset to push the mandrel 17.15 back to its original position; the mandrel 17.15 cooperates with the density ring 17.13 to ensure the complete sealing of the high-pressure air cavity and the external environment.

[0058] Overpressure release: The adjusting screw 17.20 is used to adjust the compression degree of the spring three 17.19, thereby setting the maximum pressure value in the high-pressure gas cavity; when the air pressure in the high-pressure gas cavity exceeds the set value, the gas pushes the sealing nail 17.18 to compress the spring three 17.19 and open the gas valve; the high-pressure gas is discharged through the center hole of the sealing nail 17.18 to achieve overpressure protection.

Claims

1. A linear actuator with power-off self-locking and constant support force, characterized in that: include: A drive assembly (8) is used to convert electrical energy into rotational kinetic energy to drive the actuator to operate; a gas spring unit (17) includes a gas charging valve (17.1) and a movable plug (18), provides a constant supporting force through a built-in high-pressure gas chamber, and adjusts the gas pressure through the gas charging valve (17.1) to adjust the supporting force; a brake assembly (21) includes a moving permanent magnet (21.1), a coil (21.2), a spring (21.3) and an opening and closing rod (21.7), and is used to achieve a self-locking function through a liquid sealing structure when power is off to ensure that the output end position is maintained; a planetary roller screw pair (22) includes a planetary roller screw nut (22.1), a center screw (22.2), a planetary screw (22.3) and a retaining frame (22.4), and is used to convert the rotational kinetic energy of the drive assembly (8) into linear motion; A drive assembly of a linear actuator with power-off self-locking and constant supporting force, characterized in that it comprises: a rear end cover (3), a front end cover (12) and a linear actuator housing (7), which are sealed by a sealing ring (4) and a sealing ring (11); a motor stator (8.1) and a multi-stage magnetic ring (9), wherein the motor stator (8.1) drives the multi-stage magnetic ring (9) to rotate; a deep groove ball bearing (6) and a four-point contact ball bearing (10), which respectively provide support and stability for the rotation of the multi-stage magnetic ring (9); and a wave-shaped gasket (5), which compensates for the axial clearance of the deep groove ball bearing (6) through its elastic characteristics. A planetary roller screw pair of a linear actuator with power-off self-locking and constant supporting force, characterized in that it comprises: a planetary roller screw nut (22.1), a center screw (22.2) and a planetary screw (22.3); the planetary roller screw nut (22.1) is fixedly connected to a multi-stage magnetic ring (9) and moves with the multi-stage magnetic ring; the center screw (22.2) has a high-precision smooth inner hole for serving as a high-pressure chamber of a gas spring; A gas spring unit of a linear actuator with power-off self-locking and constant supporting force, characterized in that it comprises: an inflation valve (17.1) and a movable plug (18), which are arranged in the inner hole of a central lead screw (22.2) to form a high-pressure air chamber; the high-pressure air chamber is filled with high-pressure nitrogen, and the gas pressure is adjusted by the inflation valve (17.1) to dynamically adjust the supporting force; the movable plug (18) moves axially along the central lead screw (22.2) as the pressure in the high-pressure air chamber changes, so as to adjust the direction and range of the supporting force. A brake assembly of a linear actuator with power-off self-locking and constant supporting force, characterized in that it comprises: a moving permanent magnet (21.1), a coil (21.2) and a spring (21.3), wherein when the coil (21.2) is energized, the moving permanent magnet (21.1) is attracted to make an opening and closing rod (21.7) in an open position, and when the power is off, the spring (21.3) makes the opening and closing rod (21.7) in a closed position; an A cavity and a B cavity are respectively located on both sides of an inner hole of a central lead screw (22.2), and the opening and closing of the opening and closing rod (21.7) is used to control whether the liquid can flow, thereby controlling whether the central lead screw (22.2) can move axially, thereby realizing a power-off self-locking function.

2. A linear actuator with power-off self-locking and constant supporting force according to claim 1, characterized in that: The drive assembly (8) comprises a rear end cover (3), a sealing ring (4), a corrugated gasket (5), a deep groove ball bearing (6), a linear actuator housing (7), a motor stator (8.1), a multi-stage magnetic ring (9), a four-point contact ball bearing (10), a sealing ring (11) and a front end cover (12), and motion output is achieved through the coordinated work of the motor stator (8.1) and the multi-stage magnetic ring (9).

3. The linear actuator according to claim 2, characterized in that: The elastic properties of the wave-shaped gasket (5) are used to compensate for the axial clearance of the deep groove ball bearing (6), thereby eliminating the axial clearance of the linear actuator.

4. The linear actuator according to claim 1, characterized in that: The gas spring unit (17) comprises an inflation valve (17.1) and a movable plug (18), and the pressure in the high-pressure gas chamber is adjusted via the inflation valve (17.1) to adjust the size of the supporting force.

5. The linear actuator according to claim 4, characterized in that: The high-pressure gas chamber prevents leakage of high-pressure nitrogen through a sealing structure, thereby ensuring long-term stable operation of the gas spring unit (17).

6. The linear actuator according to claim 1, characterized in that: The brake assembly (21) comprises a coil (21.2), a moving permanent magnet (21.1) and a spring (21.3); when the coil (21.2) is powered off, the moving permanent magnet (21.1) is attracted to the fixed permanent magnet (21.15) under the action of the spring (21.3), thereby realizing a power-off self-locking function.

7. The linear actuator according to claim 6, characterized in that: The inner hole of the central lead screw (22.2) is divided into chamber A and chamber B. Chamber A and chamber B realize fluid control through the linkage of the piston rod (21.6) and the opening and closing rod (21.7), thereby controlling the movement state of the central lead screw (22.2).

8. The linear actuator according to claim 1, characterized in that: The encoder assembly comprises a code disc mounting seat (25), an encoder code disc (26) and an encoder reader (27), and is used to record and feed back the motion position information of the actuator in real time to achieve precise control.

9. The linear actuator according to claim 8, characterized in that The encoder code disc (26) is fixedly connected to the lead screw nut (22.1), and when the lead screw nut (22.1) rotates, the encoder code disc (26) rotates synchronously, thereby transmitting position information.

10. The inflation valve (17.1) according to claim 4, comprising an air valve housing (17.11), a sealing assembly, a reset assembly, a spindle assembly and an overpressure protection assembly, characterized in that: The air valve housing (17.11) is used to accommodate and protect the internal components of the inflation valve (17.1), and is provided with an inflation hole and a passage leading to the high-pressure air chamber; the sealing assembly comprises a density ring six (17.12) and a density ring seven (17.13), wherein the density ring six (17.12) is arranged at the contact point between the inflation hole and the external inflation tube (17.21) for forming a seal during inflation, and the density ring seven (17.13) is arranged at the reset position of the core shaft (17.15) for isolating the high-pressure air chamber from the external environment when the inflation valve (17.1) is closed; the reset assembly comprises a spring two (17.14) and a fixed shaft (17.16), wherein the spring two (17.14) is used to provide the core shaft (17.15) with reset when the external inflation tube (17.21) is inserted or pulled out The elastic force, the fixed shaft (17.16) is used to stabilize the position of the core shaft (17.15) and the spring two (17.14); the core shaft assembly includes a core shaft (17.15) and a retaining spring (17.17); the core shaft (17.15) is pushed to form a gas channel when the external inflation tube (17.21) is inserted, and is reset to close the gas channel when the external inflation tube (17.21) is pulled out; the overpressure protection assembly includes a sealing pin (17.18), a spring three (17.19) and an adjusting screw (17.20); the adjusting screw (17.20) is used to adjust the compression degree of the spring three (17.19) to set the maximum pressure value in the high-pressure gas cavity; the sealing pin (17.18) is pushed to open the exhaust channel when the pressure in the high-pressure gas cavity exceeds the set value to achieve overpressure.

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