Secure release linear actuator

Abstract

The invention discloses a safety release linear actuator, which belongs to the technical field of actuating equipment, and comprises an actuating unit, a screw rod, a tubular telescopic component doing linear telescopic motion, a clutch, an operable release component, and a fluid chamber which axially extends in the screw rod and is filled with damping fluid, and the fluid chamber is provided with a first end and a second end, the piston rod is inserted into the fluid cavity and connected with the tubular telescopic component, the piston rod is provided with a piston element, the fluid cavity is divided into a first cavity and a second cavity, and the fluid cavity is provided with a damping channel allowing damping fluid to flow through the piston element to communicate the first cavity with the second cavity. The damping fluid flows through the damping channel in a limited manner after the linear actuator activates the release function to provide a damping force against the load force. Through the structural improvement, the release speed of the tubular telescopic component is effectively slowed down while the actuating efficiency is slightly sacrificed, so that the actuating efficiency and the working safety are effectively balanced, and the safety performance of a product is favorably improved.

Description

Technical Field

[0001] The invention relates to the technical field of actuating equipment, and in particular to a safe-release linear actuator. Background Art

[0002] Linear actuators, also known as electric push rods, are widely used in furniture, medical equipment, solar power generation and other fields. They mainly include an actuating unit that outputs an actuating torque, a screw driven to rotate by the actuating torque, and a tubular telescopic component sleeved on the outside of the screw. The tubular telescopic component includes a nut sleeved on the screw through a threaded fit and an inner tube fixedly sleeved on the nut. When working, the actuating unit drives the screw to rotate, and the rotating screw drives the nut to move along the axial direction of the screw, and the axially moving nut drives the inner tube to move synchronously, thereby making the tubular telescopic component perform linear telescopic motion.

[0003] Combined with the application scenarios of linear actuators, when the linear actuator encounters motor failure or power failure and needs to cut off the power, in order to release the tubular telescopic component so that it can be retracted smoothly, a clutch structure and an operable release component are usually added, wherein the clutch structure is used to maintain or cut off the power transmission between the actuating unit and the screw rod. By operating the release component, the clutch structure can cut off the power transmission between the actuating unit and the screw rod and activate the release function, so that the screw rod rotates under the action of the load and drives the tubular telescopic component to retract quickly for release. The larger the load, the faster the release speed of the tubular telescopic component. When the linear actuator is used as a push actuator on an electric bed, a too fast release speed can easily cause harm to the patient. When the linear actuator is used as a pull actuator in the lifting field, the heavier the load, the faster the release speed will be, which can easily cause damage to the load, people or objects under the load, etc. Summary of the invention

[0004] In order to address the shortcomings and deficiencies in the above-mentioned prior art, the present invention provides a linear actuator with safe release, which effectively slows down the release speed of the tubular telescopic component while slightly sacrificing the actuation efficiency through structural improvement, so that the actuation efficiency and work safety are effectively balanced, which is beneficial to improving the safety performance of the product.

[0005] In order to achieve the above technical objectives, the present invention provides a safe release linear actuator, comprising:

[0006] an actuating unit providing an actuating torque;

[0007] A lead screw driven to rotate by an actuating torque;

[0008] A tubular telescopic component is sleeved outside the screw and driven by the rotational motion of the screw to perform linear telescopic motion;

[0009] A clutch, which is used to maintain or cut off the power transmission between the actuating unit and the screw rod;

[0010] An operable release component that drives the clutch to cut off power transmission between the actuation unit and the lead screw to activate a release function of the linear actuator;

[0011] The linear actuator further comprises:

[0012] A fluid chamber axially extending inside the screw and filled with a damping fluid, the fluid chamber having a first end close to the actuating unit and a second end away from the actuating unit;

[0013] A piston rod inserted into the fluid chamber, which is connected to the tubular telescopic component, wherein the portion of the piston rod inserted into the fluid chamber is provided with a piston element, and the fluid chamber is divided into a first chamber between the piston element and the first end and a second chamber between the piston element and the second end;

[0014] a damping passage, disposed inside the fluid chamber and allowing the damping fluid to flow through the piston element to communicate with the first chamber and the second chamber;

[0015] After the linear actuator activates the release function, the damping fluid is restricted to flow through the damping channel to provide a damping force to resist the load force.

[0016] Further, the linear actuator is configured to push the actuator, and the tubular telescopic component pushes the load in a direction away from the actuator unit. After the linear actuator activates the release function, the tubular telescopic component is released in a direction close to the actuator unit under the thrust of the load, and the damping fluid in the first chamber flows through the damping channel in a restricted manner into the second chamber, providing a damping force to counteract the load thrust.

[0017] Furthermore, the linear actuator is configured as a pulling actuator, and the tubular telescopic component pulls the load in a direction close to the actuating unit. After the linear actuator activates the release function, the tubular telescopic component is released in a direction away from the actuating unit under the load pulling force, and the damping fluid in the second chamber flows through the damping channel in a restricted manner into the first chamber, providing a damping force to counteract the load pulling force.

[0018] Furthermore, the linear movement of the tubular telescopic component in a first direction is defined as a working stroke, and the linear movement of the tubular telescopic component in a second direction opposite to the first direction under a load force is defined as a release stroke. The cross-sectional area of ​​at least part of the damping channel is variable, so that the part of the damping channel provides a larger cross-sectional area in the working stroke of the tubular telescopic component than in the release stroke.

[0019] Furthermore, at least a partial gap is reserved between the portion of the inner circumference of the fluid chamber corresponding to the piston element and the outer circumference of the piston element to form the damping channel, and the piston element undergoes reversible radial deformation due to the damping fluid pressure to change the cross-sectional area of ​​the damping channel.

[0020] Furthermore, a circumferentially continuous damping channel is formed between a portion of the inner circumferential surface of the fluid chamber corresponding to the piston element and an outer circumferential surface of the piston element.

[0021] Further, the piston element has a radial pressure-bearing surface and an axial pressure-bearing surface;

[0022] During the working stroke of the tubular telescopic component, the radial pressure-bearing surface is located on the pressure-bearing side of the piston element, and bears the radial pressure of the damping fluid to cause the piston element to deform radially inward, and the axial pressure-bearing surface is located on the back-pressure side of the piston element;

[0023] During the release stroke of the tubular telescopic component, the axial pressure-bearing surface is located on the pressure-bearing side of the piston element, and bears the axial pressure of the damping fluid to cause the piston element to deform radially outward, and the radial pressure-bearing surface is located on the back-pressure side of the piston element.

[0024] Further, the piston element comprises a first end face and a second end face which are axially separated, the outer peripheral surface of the piston element is connected between the first end face and the second end face, and the axial extension direction from the first end face to the second end face is defined to be consistent with the first direction;

[0025] At least part of the first end surface of the piston element constitutes the axial pressure-bearing surface;

[0026] At least part of the outer circumference of the piston element constitutes a radial pressure-bearing surface, and this part of the outer circumference gradually deviates toward the axis of the piston element along the first direction, and the cross-sectional area of ​​the part of the damping channel corresponding to the radial pressure-bearing surface increases unidirectionally along the first direction.

[0027] Furthermore, part of the outer peripheral surface of the piston element constitutes an equal-diameter surface, and the equal-diameter surface is located between the axial pressure-bearing surface and the radial pressure-bearing surface.

[0028] Furthermore, the linear actuator also includes a fixing element, which includes a connecting portion, a limiting portion and a supporting portion located therebetween, the connecting portion passing through the piston element and connected to the insertion end of the piston rod, the piston element is axially clamped and limited by the insertion end of the piston rod and the limiting portion, and the supporting portion axially penetrates the piston element for its centering and support.

[0029] Further, the connection between the connecting portion and the insertion end of the piston rod is configured as a threaded fitting connection; and / or the connection between the limiting portion and the supporting portion is configured as a threaded fitting connection.

[0030] Furthermore, the first end of the fluid chamber is a closed end, and the second end provides an opening for inserting the piston rod. A sealing element is configured at the opening to provide a dynamic seal between the second end and the piston rod.

[0031] Further, the damping channel includes a hole axially penetrating the piston element; and / or the damping channel includes a groove axially extending on the inner circumferential surface of the fluid chamber.

[0032] After adopting the above technical solution, the present invention has the following advantages:

[0033] 1. The linear actuator provided by the present invention has a fluid chamber extending axially and filled with damping fluid inside the screw rod, a piston rod is inserted in the fluid chamber and connected to a tubular telescopic component, and a piston element configured with the piston rod divides the fluid chamber into a first chamber and a second chamber that can be connected through a damping channel.

[0034] When the linear actuator is activated and released, the tubular telescopic component moves linearly under the action of the load and has a certain release speed. The piston rod follows the tubular telescopic component to move linearly in the fluid chamber. The damping fluid in the fluid chamber flows in the opposite direction to the piston rod. Since the reverse-flowing damping fluid is restricted in flowing through the damping channel, the reverse-flowing damping fluid will cause the tubular telescopic component to be subjected to a damping force opposite to the load force. The damping force can effectively slow down the release speed of the tubular telescopic component, thereby avoiding safety risks or damages caused by the tubular telescopic component being released too quickly under the action of the load force.

[0035] When the actuating unit actuates the load through the lead screw and the tubular telescopic component, the tubular telescopic component performing linear motion drives the load to move synchronously. At this time, the piston rod follows the tubular telescopic component to perform linear motion in the fluid chamber, and the damping fluid in the fluid chamber also flows in the reverse direction relative to the piston rod. Since the reverse-flowing damping fluid is restricted in flowing through the damping channel, the reverse-flowing damping fluid causes the tubular telescopic component to be subjected to a damping force in the opposite direction to the actuating force, thereby slowing down the actuation speed of the tubular telescopic component on the load.

[0036] Although the damping structure composed of features such as the piston rod, piston element, damping channel, and damping fluid will slow down the actuation speed of the tubular telescopic component to the load, the damping structure can also effectively slow down the release speed of the tubular telescopic component under the action of the load, avoiding safety risks or damage caused by excessive release speed. Through structural improvements, the release speed of the tubular telescopic component can be effectively slowed down while slightly sacrificing the actuation efficiency, so that the actuation efficiency and work safety are effectively balanced, which is beneficial to improving the safety performance of the product.

[0037] 2. When the linear actuator is configured to push the actuator, after the release function is activated, the tubular telescopic component is released in the direction close to the actuating unit under the thrust of the load, and the piston rod moves toward the actuating unit in the fluid chamber. At this time, the damping fluid in the first chamber is restricted to flow toward the second chamber through the damping channel. The damping fluid flowing in the opposite direction to the piston rod causes the tubular telescopic component to be subjected to a damping force that counteracts the thrust of the load, thereby achieving the purpose of slowing down the release speed of the tubular telescopic component and the load.

[0038] 3. When the linear actuator is configured as a pulling actuator, after the release function is activated, the tubular telescopic component is released in a direction away from the actuating unit under the tensile force of the load, and the piston rod moves away from the actuating unit in the fluid chamber. At this time, the damping fluid in the second chamber is restricted to flow toward the first chamber through the damping channel. The damping fluid flowing in the opposite direction to the piston rod causes the tubular telescopic component to be subjected to a damping force that counteracts the tensile force of the load, thereby achieving the purpose of slowing down the release speed of the tubular telescopic component and the load.

[0039] 4. The cross-sectional area of ​​at least part of the damping channel is preferably variable, and the part of the damping channel provides a larger cross-sectional area in the working stroke of the tubular telescopic component than in the release stroke. By changing the cross-sectional area of ​​the damping channel, the reverse flow rate of the damping fluid when the tubular telescopic component is actuated is increased, and the actuation damping force of the tubular telescopic component caused by the damping fluid flowing in the reverse direction is appropriately reduced, which is conducive to ensuring the actuation efficiency of the tubular telescopic component. By improving, the damping force of the damping structure on the tubular telescopic component is ensured to be released, and at the same time, the actuation damping force on the tubular telescopic component is minimized.

[0040] 5. At least a partial reserved gap between the inner circumference of the fluid chamber and the outer circumference of the piston element constitutes a damping channel. When the damping fluid flows in the reverse direction relative to the piston rod, the pressure of the damping fluid causes the piston element to produce reversible radial deformation. The greater the load force borne by the tubular telescopic component, the greater the pressure exerted by the damping fluid on the piston element, the greater the radial deformation of the piston element, the narrower the damping channel, the smaller the flow rate of the damping fluid, and the greater the damping force of the damping fluid on the tubular telescopic component. The cross-sectional area of ​​the damping channel is changed by the radial deformation of the piston element, so that the cross-sectional area of ​​the damping channel can be adaptively changed according to the size of the load force, so that the tubular telescopic component can obtain a basically consistent release speed under the action of different load forces. When the load force is greater, the cross-sectional area of ​​the damping channel is smaller, and the damping force of the damping fluid on the tubular telescopic component is greater.

[0041] 6. The damping channel is preferably arranged continuously along the circumference, and the shape of the damping channel is reasonably set to maximize the contact area between the damping fluid and the piston element, thereby increasing the radial deformation amplitude of the piston element under the pressure of the damping fluid, and further improving the release damping force exerted on the tubular telescopic component by the damping fluid. Whether in the working stroke or in the release stroke, the piston rod moves synchronously with the tubular telescopic component. A reasonable shape of the piston element helps to achieve uniform distribution of pressure, such as using some symmetrical cylindrical or spherical designs. The present invention optimizes the layout and shape of the damping channel so that the damping fluid flows evenly around the piston element, thereby generating a uniform pressure distribution, which helps to maintain good concentricity between the piston rod and the tubular telescopic component during dynamic movement.

[0042] 7. During the working stroke of the tubular telescopic component, the radial pressure-bearing surface of the piston element is located on the pressure-bearing side of the piston element, and the axial pressure-bearing surface of the piston element is located on the back-pressure side of the piston element. The damping fluid flowing in the reverse direction relative to the tubular telescopic component directly acts on the radial pressure-bearing surface to subject the piston element to radial pressure. The piston element subjected to the radial pressure produces a radial inward deformation, that is, the piston element will become thinner under pressure. Correspondingly, the cross-sectional area of ​​the damping channel becomes larger, and the damping fluid flowing in the reverse direction can basically flow smoothly, thereby reducing the actuation damping of the tubular telescopic component, thereby ensuring the actuation efficiency of the tubular telescopic component.

[0043] During the release stroke of the tubular telescopic component, the radial pressure-bearing surface of the piston element is located on the back-pressure side of the piston element, and the axial pressure-bearing surface of the piston element is located on the pressure-bearing side of the piston element. The damping fluid flowing in the reverse direction relative to the tubular telescopic component directly acts on the axial pressure-bearing surface to subject the piston element to axial pressure. The piston element subjected to the axial pressure will deform radially outward, that is, the piston element will become thicker under pressure. Correspondingly, the cross-sectional area of ​​the damping channel will become smaller, and the flow of the damping fluid flowing in the reverse direction will be obstructed, thereby increasing the release damping of the tubular telescopic component, thereby ensuring the release damping effect of the damping fluid on the tubular telescopic component.

[0044] 8. At least part of the outer peripheral surface of the piston element constitutes a radial pressure-bearing surface, and the radial pressure-bearing surface gradually deviates toward the axis along the first direction, that is, the radial pressure-bearing surface is preferably set to a conical surface structure, and accordingly, the cross-sectional area of ​​the portion of the damping channel corresponding to the radial pressure-bearing surface increases along the first direction. The shape of the radial pressure-bearing surface is reasonably set, so as to reasonably increase the outer diameter of the axial pressure-bearing surface, thereby increasing the contact area between the damping fluid flowing in the reverse direction and the piston element when the tubular telescopic component is released, increasing the axial pressure on the piston element, further reducing the cross-sectional area of ​​the damping channel, and further increasing the release damping of the tubular telescopic component caused by the damping fluid flowing in the reverse direction. In addition, since the radial pressure-bearing surface is a conical surface structure, the radial pressure on the piston element caused by the damping fluid when the tubular telescopic component is actuated can be increased, so that the piston element with a thinned pressure-bearing surface can effectively increase the cross-sectional area of ​​the damping channel, and further reduce the actuation damping of the tubular telescopic component caused by the damping fluid flowing in the reverse direction, thereby ensuring the actuation efficiency of the tubular telescopic component.

[0045] 9. Part of the outer peripheral surface of the piston element is preferably formed as an equal-diameter surface between the axial pressure-bearing surface and the radial pressure-bearing surface. The equal-diameter surface allows the maximum outer diameter of the piston element to remain basically stable during radial deformation when it becomes thicker under axial pressure or becomes thinner under radial pressure, thereby allowing the minimum cross-sectional area of ​​the damping channel to remain basically stable during radial deformation of the piston element. As a result, the tubular telescopic component can be subjected to stable damping when released or actuated, thereby avoiding the situation where the tubular telescopic component moves faster or slower due to the fluctuating damping effect, thereby improving the movement stability of the tubular telescopic component.

[0046] 10. The piston element is connected to the piston rod by using a fixing element. At the same time, the piston element is centered and supported by the supporting portion of the fixing element to ensure the structural stability of the piston element and improve the stability of the damping effect of the damping structure on the release of the tubular telescopic component. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is an overall diagram of the linear actuator in the first embodiment;

[0048] Figure 2 is an exploded view of the linear actuator in Embodiment 1;

[0049] Figure 3 is an axial cross-sectional view of the tubular telescopic component and the screw rod in the first embodiment;

[0050] Figure 4 It is a partial structural diagram of the inner part of the screw rod in the first embodiment;

[0051] Figure 5 It is a structural diagram of the piston rod, the piston element and the fixing element in the first embodiment;

[0052] Figure 6 is an axial cross-sectional view of the piston element in the first embodiment;

[0053] Figure 7 is a structural diagram of a fixing element in Embodiment 1;

[0054] Figure 8 It is a partial structural diagram of the inner part of the screw rod when the push actuator in the first embodiment pushes the load;

[0055] Fig. 9 It is a partial structural diagram of the inner part of the screw rod when the push actuator is activated to release the function in the first embodiment;

[0056] Fig.10 It is an axial cross-sectional view of the housing, clutch, screw rod and coupling structure in the first embodiment;

[0057] Fig.11 It is an axial cross-sectional view of the clutch, the screw rod and the coupling structure in the first embodiment;

[0058] Fig.12 An exploded view of the clutch, the lead screw and the coupling structure in the first embodiment;

[0059] Fig.13 It is a diagram showing the coordination of a partial structure of the clutch, the lead screw and the coupling structure in the first embodiment;

[0060] Fig.14 It is a diagram showing the coordination of another part of the structure of the clutch, the lead screw and the coupling structure in the first embodiment;

[0061] Fig.15 is a radial cross-sectional view of a portion of the structure of the clutch in the first embodiment;

[0062] Fig.16 is a structural diagram of the torque input member in the first embodiment;

[0063] Fig.17 is a structural diagram of the torque output member in the first embodiment;

[0064] Fig.18 An exploded view of the retaining ring and the brake block in the first embodiment;

[0065] Fig.19 It is a structural diagram of a part of the structure of the clutch, the lead screw and the coupling structure in the first embodiment when the coupling structure is separated;

[0066] Fig. 20 It is a partial structural diagram of the release component in the first embodiment in the normal state;

[0067] Fig.21 It is a partial structural diagram of the release component in the first embodiment when the release function is activated;

[0068] Fig. 22 It is a partial structural diagram of the inner part of the screw rod when the pulling actuator in the second embodiment is pulling the load;

[0069] Fig.23 It is a partial structural diagram of the inner part of the screw rod when the pull actuator is activated to release the function in the second embodiment;

[0070] Fig.24 is an axial cross-sectional view of a piston element used to push the actuator in Embodiment 3;

[0071] Fig.25 It is an axial cross-sectional view of the piston element used in the pulling actuator in the third embodiment.

[0072] In the figure, 10-linear actuator, 110-actuating unit, 120-transmission structure, 121-worm, 122-worm wheel, 200-screw, 210-fluid chamber, 211-first chamber, 212-second chamber, 213-damping channel, 220-threaded section, 230-optical axis section, 231-first axis section, 232-second axis section, 240-first spring, 250-positioning sheet, 300-tubular telescopic component, 310-inner tube, 320-outer tube, 330-thread Mother, 340-end cover, 350-front joint, 360-sealing element, 400-clutch, 401-sun gear, 402-planetary gear, 403-planet carrier, 4031-front frame, 4032-rear frame, 404-inner gear ring, 405-brake seat, 406-torque input member, 4061-input key, 407-torque output member, 4071-output key, 4072-self-locking angle, 408-retaining ring, 4081-retaining key, 4082-arc groove, 40 9-brake block, 410-torsion spring, 4101-first torsion foot, 411-limiting ring, 500-release component, 510-cable, 520-release connecting rod, 530-slide plate, 531-limiting hole, 532-long hole, 540-second spring, 550-pin, 610-piston rod, 620-piston element, 621-first end face, 622-second end face, 623-outer peripheral surface, 623a-conical surface, 623b-equal diameter surface, 624-through hole, 625-conical Hole, 630-damping fluid, 640-fixing element, 641-connecting part, 642-supporting part, 643-limiting part, 710-housing, 711-limiting plate, 712-limiting groove, 720-rear joint, 730-front positioning seat, 740-rear positioning seat, 800-coupling structure, 810-active coupling, 820-driven coupling, E1-first end, E2-second end, AS-axial pressure-bearing surface, RS-radial pressure-bearing surface, PS-pressure-bearing side, BPS-back pressure side. DETAILED DESCRIPTION

[0073] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following words indicating orientation or positional relationship such as "upper", "lower", "left", "right", "longitudinal", "lateral", "inner", "outer", "vertical", "horizontal", "top", "bottom", etc. are only based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device / element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0074] Embodiment 1

[0075] Combination Figures 1 to 21 , the safe release linear actuator 10 provided in the first embodiment of the present invention comprises:

[0076] an actuation unit 110 providing an actuation torque;

[0077] A lead screw 200 driven to rotate by an actuating torque;

[0078] The tubular telescopic member 300 is mounted outside the screw rod 200 and is driven by the rotation of the screw rod 200 to perform linear telescopic motion;

[0079] The clutch 400 is used to maintain or cut off the power transmission between the actuating unit 110 and the screw rod 200;

[0080] An operable release member 500 that drives the clutch 400 to cut off the power transmission between the actuating unit 110 and the lead screw 200 and activates the release function of the linear actuator 10;

[0081] The linear actuator 10 further comprises:

[0082] A fluid chamber 210 axially extending inside the screw rod 200 and filled with a damping fluid 630 , the fluid chamber 210 having a first end E1 close to the actuating unit 110 and a second end E2 away from the actuating unit 110 ;

[0083] A piston rod 610 inserted into the fluid chamber 210 is connected to the tubular telescopic member 300. The piston rod 610 is inserted into the portion of the fluid chamber 210 where a piston element 620 is disposed. The fluid chamber 210 is divided into a first chamber 211 between the piston element 620 and the first end E1 and a second chamber 212 between the piston element 620 and the second end E2.

[0084] The damping channel 213 is disposed inside the fluid chamber 210 and allows the damping fluid 630 to flow through the piston element 620 to communicate with the first chamber 211 and the second chamber 212;

[0085] After the linear actuator 10 activates the release function, the damping fluid 630 is restricted to flow through the damping passage 213 to provide a damping force against the load force.

[0086] When the linear actuator 10 is activated and released, the tubular telescopic component 300 moves linearly under the action of the load and has a certain release speed. The piston rod 610 follows the tubular telescopic component 300 to move linearly in the fluid chamber 210. The damping fluid 630 in the fluid chamber 210 flows in the reverse direction relative to the piston rod 610. Since the reverse-flowing damping fluid 630 is restricted to flow through the damping channel 213, the reverse-flowing damping fluid 630 will cause the tubular telescopic component 300 to be subjected to a damping force opposite to the load force. The damping force can effectively slow down the release speed of the tubular telescopic component 300, thereby avoiding safety risks or damages caused by the tubular telescopic component 300 being released too quickly under the action of the load force.

[0087] Combination Figure 1 , Figure 2 In this embodiment, the linear actuator 10 further includes a housing 710, and structures such as the clutch 400 are arranged in the housing 710. The actuating unit 110 transmits power to the clutch 400 through the transmission structure 120. Specifically, the housing 710 preferably adopts a shell-type structure that is split on the left and right, and the left and right parts of the housing 710 are fixed together by fasteners. The actuating unit 110 can adopt a motor, and the transmission structure 120 can adopt a structure in which a worm 121 and a worm wheel 122 cooperate. The worm 121 is connected to the rotating shaft of the motor by transmission or integrally formed, and the worm wheel 122 is meshed with the worm 121. The worm wheel 122 is rotatably mounted in the housing 710 and the axial direction of the worm wheel 122 is basically arranged along the front-back direction. The motor outputs an actuating torque outward through the transmission structure 120, and the rotating worm wheel 122 can drive the screw 200 to rotate through the clutch 400. Of course, the transmission structure 120 can also adopt other structures that meet the power transmission requirements, such as a gear matching structure.

[0088] In this embodiment, the length direction of the tubular telescopic component 300 is arranged along the front-to-back direction, and the actuating unit 110, the transmission structure 120, the clutch 400, the housing 710 and other structures are arranged at the rear end of the tubular telescopic component 300. Figure 3The tubular telescopic component 300 includes an inner tube 310, an outer tube 320, a nut 330 and other components. Specifically, the nut 330 is sleeved on the outer periphery of the screw rod 200 through threaded matching, the inner tube 310 is sleeved on the outside of the screw rod 200 in the air and its rear end is fixedly sleeved on the outer periphery of the nut 330, the outer tube 320 is sleeved on the outside of the inner tube 310 in the air, the rear end of the outer tube 320 is fixedly attached to the housing 710, the front end of the outer tube 320 is provided with an end cap 340, the front end of the inner tube 310 extends forward from the end cap 340 and is provided with a front joint 350, and the rear end of the housing 710 is provided with a rear joint 720. The load is connected to the inner tube 310 of the tubular telescopic component 300 through the front joint 350, and when the screw rod 200 rotates, the inner tube 310 is driven by the nut 330 to perform linear telescopic motion in the front and rear directions, and the inner tube 310 drives the load to move synchronously through the front joint 350. Optionally, the entire linear actuator 10 can be fixedly connected or rotatably connected to other objects through the rear joint 720 .

[0089] In this embodiment, the screw rod 200 includes a threaded section 220 and an optical axis section 230 that are distributed front and back and connected to each other. The threaded section 220 of the screw rod 200 is in a hollow tubular shape. The hollow inner cavity of the threaded section 220 is used to form an elongated fluid chamber 210. The front end of the optical axis section 230 is inserted into the rear end of the threaded section 220 to close the rear end of the fluid chamber 210. The front end of the hollow tubular threaded section 230 has an opening for inserting the piston rod 610. The piston rod 610 is inserted into the fluid chamber 210 from front to back. The front end of the piston rod 610 extends out of the threaded section 220 and is connected to the front joint 350 through a fastener. The front end of the piston rod 610 is its protruding end, and the rear end of the piston rod 610 is its insertion end. The front end of the screw rod 200 is fixed with a sealing element 360, which is sleeved on the outside of the piston rod 610 through a clearance fit and inserted into the opening of the front end of the threaded section 220. The sealing element 360 and the piston rod 610, and the sealing element 360 and the inner tube 310 are both sealed circumferentially through a sealing ring. The sealing element 360 and the sealing ring are used to provide dynamic sealing for the piston rod 610 and the screw rod 200, and the sealing element 360 is also used to seal the front end of the fluid chamber 210, so that the fluid chamber 210 is a closed chamber to prevent the damping fluid 630 from leaking outward. The rear end of the fluid chamber 210 constitutes a first end E1 close to the actuating unit 110, and the front end of the fluid chamber 210 constitutes a second end E2 away from the actuating unit 110. In this embodiment, the damping fluid 630 can be a liquid with a certain viscosity such as hydraulic oil, or a pressurized gas, as long as it meets the damping requirements, and no excessive restrictions are made here.

[0090] Combination Figure 4 , Figure 5In this embodiment, the piston element 620 is arranged at the rear end of the piston rod 610 through the fixing element 640, the portion of the fluid chamber 210 located between the piston element 620 and the front end of the optical axis section 230 constitutes the first chamber 211, the portion of the fluid chamber 210 located between the piston element 620 and the sealing element 360 constitutes the second chamber 212, and the portion of the fluid chamber 210 corresponding to the piston element 620 constitutes the damping channel 213. The first chamber 211, the damping channel 213 and the second chamber 212 are distributed in sequence from back to front, and the first chamber 211 and the second chamber 212 can be connected through the damping channel 213.

[0091] The piston rod 610, the piston element 620, the damping fluid 630 and the damping channel 213 constitute a damping structure for slowing down the release movement speed of the tubular telescopic component 300. This embodiment takes the push actuator as an example to specifically describe the damping structure. In the push actuator, the tubular telescopic component 300 can push the load in a direction away from the actuating unit 110 through the front joint 350. The forward linear movement of the tubular telescopic component 300 is a normal working stroke. At this time, the piston rod 610 and the piston element 620 move forward synchronously with the tubular telescopic component 300. When the actuator is pushed to activate the release function, the tubular telescopic component 300 is released in the direction close to the actuating unit 110 by the force of the load, and the linear movement backward of the tubular telescopic component 300 under the load force is the release stroke. At this time, the piston rod 610 and the piston element 620 move backward synchronously with the tubular telescopic component 300. Under the action of the piston element 620, the damping fluid 630 in the first chamber 211 is restricted to flow through the damping channel 213 toward the second chamber 212, that is, the damping fluid 630 flows in the opposite direction to the piston rod 610 and the piston element 620 moving backward, and the damping fluid 630 flowing in the opposite direction provides a damping force to counteract the load pressure.

[0092] Combination Figure 4In this embodiment, the outer diameter of the piston element 620 is smaller than the inner diameter of the fluid chamber 210, and the reserved gap between the outer circumference 623 of the piston element 620 and the inner circumference of the fluid chamber 210 constitutes the damping channel 213. Since the cross-sectional area of ​​the damping channel 213 affects the flow rate of the damping fluid 630, and the flow rate of the damping fluid 630 affects its damping force on the tubular telescopic component 300, in order to make the cross-sectional area of ​​the damping channel 213 adaptively change according to the magnitude of the load force, the piston element 620 can produce a reversible deformation when subjected to the pressure of the damping fluid 630, and the cross-sectional area of ​​the damping channel 213 is changed by the deformation of the piston element 620, so that the tubular telescopic component 300 can obtain a substantially consistent release speed under the action of different load forces. Specifically, the piston element 620 in this embodiment is columnar and its axial direction is arranged roughly along the front-to-back direction. The reserved gap between the outer circumference 623 of the piston element 620 and the inner circumference of the fluid chamber 210 is preferably arranged continuously along the circumferential direction. Correspondingly, the damping channel 213 is also arranged continuously along the circumferential direction, that is, the damping channel 213 is annular. Figure 6 The piston element 620 includes a first end face 621 at the rear end, a second end face 622 at the front end, and an outer peripheral surface 623 between the first end face 621 and the second end face 622. The first end face 621 and the second end face 622 are spaced apart from each other in the axial direction, and the outer peripheral surface 623 of the piston element 620 is connected between the first end face 621 and the second end face 622. As an alternative to this embodiment, the damping channel 213 may be intermittently arranged in the circumferential direction by changing the shape of the piston element, or the damping channel 213 may be in an arc shape or other reasonable shapes along the cross section perpendicular to the axial direction.

[0093] In this embodiment, the piston element 620 is provided with a through hole 624 that cooperates with the fixing element 640. The fixing element 640 passes through the through hole 624 and is connected to the rear end of the piston rod 610. Figure 7The fixing element 640 includes a connecting portion 641, a supporting portion 642 and a limiting portion 643 distributed from front to back. The connecting portion 641 passes through the piston element 620 from back to front and is connected to the rear end of the piston rod 610. The supporting portion 642 is inserted into the through hole 624 and axially penetrates the piston element 620. The piston element 620 is radially limited and supported by the cooperation between the supporting portion 642 and the through hole 624. The limiting portion 643 is located behind the first end face 621, and the outer diameter of the limiting portion 643 is larger than the aperture of the through hole 624. The entire piston element 620 is clamped between the rear end face of the piston rod 610 and the limiting portion 643, so that the piston element 620 is axially limited. Furthermore, a threaded hole can be provided at the rear end of the piston rod 610, and the connecting portion 641 is connected to the rear end of the piston rod 610 by threaded matching, so that the depth of the connecting portion 641 screwed into the threaded hole can be adjusted according to the axial length of the piston element 620, thereby adjusting the position of the limiting portion 643 relative to the piston element 620, and ensuring the limiting effect of the limiting portion 643 on the piston element 620; of course, the connecting portion 641 can also be connected to the rear end of the piston rod 610 by other matching, and no excessive restrictions are made here. In addition, the connecting portion 641, the supporting portion 642 and the limiting portion 643 of the fixing element 640 can be integrally formed, or they can be separately formed and then connected together; of course, the connecting portion 641 and the supporting portion 642 can also be integrally formed, and the limiting portion 643 is connected to the rear end of the supporting portion 642 by threaded matching. At this time, the limiting portion 643 can adjust the position relative to the piston element 620 by threaded matching according to the axial length of the piston element 620, and ensure the limiting effect of the limiting portion 643 on the piston element 620.

[0094] In the push actuator, the first end surface 621 of the piston element 620 constitutes an axial pressure bearing surface (AS), and at least a portion of the outer peripheral surface 623 of the piston element 620 constitutes a radial pressure bearing surface (RS).

[0095] Combination Figure 8When the tubular telescopic component 300 of the actuator pushes the load to move forward, the distance the tubular telescopic component 300 moves forward constitutes the working stroke generated by its linear motion along the first direction, that is, the first direction in this embodiment is the forward direction. At this time, the piston rod 610 and the piston element 620 move backward in the fluid chamber 210, and the damping fluid 630 in the fluid chamber 210 is squeezed and flows from the second chamber 212 in front to the first chamber 211 in the rear, that is, the damping fluid 630 flows in the reverse direction relative to the piston rod 610. At the same time, the radial pressure-bearing surface RS is located on the pressure side (PS, Pressure Side) of the piston element 620, and the axial pressure-bearing surface AS is located on the back pressure side (BPS, Back Pressure Side) of the piston element 620. In order to minimize the damping force Fd1 of the reverse-flowing damping fluid 630 on the tubular telescopic component 300, the piston element 620 preferably produces a radial inward deformation when subjected to the pressure of the damping fluid 630, that is, the piston element 620 becomes thinner under pressure, and correspondingly, the cross-sectional area of ​​the damping channel 213 becomes larger. The reverse-flowing damping fluid 630 reduces the damping force Fd1 on the tubular telescopic component 300, thereby ensuring the actuation efficiency of the tubular telescopic component 300.

[0096] Combination Fig. 9 When the push actuator is activated to release, the tubular telescopic component 300 moves backward under the action of the load pressure Fb1, and the distance the tubular telescopic component 300 moves backward under the load pressure Fb1 constitutes the release stroke generated by its linear motion along the second direction, that is, the second direction in this embodiment is the backward direction. At this time, the piston rod 610 and the piston element 620 move backward in the fluid chamber 210, and the damping fluid 630 in the fluid chamber 210 is squeezed and flows from the first chamber 211 at the rear to the second chamber 212 at the front, that is, the damping fluid 630 flows in the opposite direction relative to the piston rod 610. At the same time, the axial pressure-bearing surface AS is located on the pressure-bearing side PS of the piston element 620, and the radial pressure-bearing surface RS is located on the back-pressure side BPS of the piston element 620. In order to ensure the damping force of the damping fluid 630 flowing in the reverse direction on the tubular telescopic component 300, the piston element 620 preferably produces a radial outward deformation when subjected to the pressure of the damping fluid 630, that is, the piston element 620 becomes thicker under pressure, and accordingly, the cross-sectional area of ​​the damping channel 213 becomes smaller. The damping fluid 630 flowing in the reverse direction increases the damping force Fd2 on the tubular telescopic component 300, thereby allowing the tubular telescopic component 300 to be slowly released under the action of the load pressure Fb1.

[0097] In order to allow the piston element 620 to deform adaptively according to the motion state of the tubular telescopic component 300, in this embodiment, the piston element 620 is roughly cylindrical and thin at the front and thick at the back. Accordingly, the outer peripheral surface 623 of the piston element 620 has a tapered surface 623a that is thin at the front and thick at the back. The tapered surface 623a constitutes the radial pressure-bearing surface RS. Figure 8 When the tubular telescopic component 300 is normally actuated to load, the piston rod 610 and the piston element 620 move from back to front, and accordingly, the damping fluid 630 flows from front to back. The damping fluid 630 flowing backward contacts the conical surface 623a located on the pressure-bearing side PS and applies a force F1 to the piston element 620. The force F1 can be decomposed into a first force component F11 parallel to the conical surface 623a and a second force component F12 perpendicular to the conical surface 623a. The second force component F12 causes the piston element 620 to deform radially inward, that is, the piston element 620 becomes thinner under pressure, and the overall shape of the piston element 620 is approximately changed from Figure 8 The original state shown by the dotted line is deformed into the thinned state shown by the solid line. The narrowest single-side width of the damping channel 213 when the piston element 620 is not deformed is K. The narrowest single-side width of the damping channel 213 after the piston element 620 is thinned under pressure is K1, K1>K, that is, the cross-sectional area of ​​the damping channel 213 will increase, thereby appropriately reducing the damping force Fd1 of the damping fluid 630 when the tubular telescopic component 300 pushes the load. When the piston element 620 is thinned under pressure, its axial length will increase. In order to allow the piston element 620 to produce sufficient deformation, a certain axial gap can be reserved between the limit portion 643 and the first end face 621 during assembly, and the axial gap is used to provide sufficient axial deformation space for the piston element 620. In other alternatives of this embodiment, the single-sided cross-sectional shape of the radial pressure-bearing surface RS along the axial direction can also be set to other reasonable shapes such as an arc shape or a broken line shape connected by multiple line segments, so that the outer diameter of the radial pressure-bearing surface RS gradually increases from front to back.

[0098] Combination Fig. 9 When the actuator is pushed to activate the release function, the tubular telescopic component 300 moves from front to back under the action of the load pressure Fb1, and the piston rod 610 and the piston element 620 also move from front to back. Correspondingly, the damping fluid 630 flows from back to front. The damping fluid 630 flowing forward contacts the axial pressure-bearing surface AS on the pressure-bearing side PS and applies a force F2 to the piston element 620. The force F2 causes the piston element 620 to deform radially outward, that is, the piston element 620 becomes thicker under pressure, and the overall shape of the piston element 620 changes from Fig. 9The original state shown by the dashed line is deformed into the thickened state shown by the solid line. The narrowest unilateral width of the damping channel 213 when the piston element 620 is not deformed is K. After the piston element 620 is pressurized and thickened, the narrowest unilateral width of the damping channel 213 is K2, K2<K<K1, that is, the cross-sectional area of ​​the damping channel 213 will be reduced, and the damping fluid 630 in the first chamber 211 is restricted to flow through the damping channel 213 to the second chamber 212, thereby increasing the damping force Fd2 of the damping fluid 630 on the tubular telescopic component 300. When the load pressure Fb1 is applied, the greater the force F2, the greater the deformation of the piston element 620, and accordingly, the smaller K2, that is, the greater the damping force Fd2 of the damping fluid 630 on the tubular telescopic component 300. In this embodiment, the limiting portion 643 is preferably configured to be spline-shaped, thereby increasing the contact area between the damping fluid 630 flowing forward and the axial pressure-bearing surface AS, thereby increasing the force F2 exerted on the piston element 620 by the damping fluid 630, and further allowing the piston element 620 to produce sufficient deformation to minimize the cross-sectional area of ​​the damping channel 213.

[0099] In order to make the minimum cross-sectional area of ​​the damping channel 213 basically remain stable during the radial deformation of the piston element 620, in this embodiment, the outer circumferential surface 623 of the piston element 620 also has an equal diameter surface 623b, which is located between the first end surface 621 and the tapered surface 623a and extends a certain length in the axial direction. Specifically, the piston element 620 is provided with a cylindrical section of equal thickness at its rear end, and the outer circumferential surface of the cylindrical section forms an equal diameter surface 623b. The equal diameter surface 623b allows the maximum outer diameter of the piston element 620 to remain basically stable during the radial deformation when it is subjected to axial pressure and becomes thicker or when it is subjected to radial pressure and becomes thinner, so that the minimum cross-sectional area of ​​the damping channel 213 can be basically kept stable during the radial deformation of the piston element 620, and then the tubular telescopic component 300 can be subjected to a stable damping effect when it is released or actuated, avoiding the situation that the tubular telescopic component 300 moves faster or slower due to the damping effect it is subjected to, and improving the movement stability of the tubular telescopic component 300. Figure 4The straight line L1 in the figure represents the axial position of the first end face 621, the straight line L2 represents the axial position of the second end face 622, the straight line L3 represents the boundary between the tapered surface 623a and the equal-diameter surface 623b, the part of the outer peripheral surface of the piston element 620 between the straight line L2 and the straight line L3 constitutes the radial pressure-bearing surface RS which gradually deviates from the back to the front toward the axis of the piston element 620, and the part of the outer peripheral surface of the piston element 620 between the straight line L3 and the straight line L1 constitutes the equal-diameter surface 623b. Accordingly, the cross-sectional area of ​​the part of the damping channel 213 between the straight line L2 and the straight line L3 gradually increases from the back to the front, and the cross-sectional area of ​​the part of the damping channel 213 between the straight line L3 and the straight line L1 is basically consistent from front to back. Of course, as an alternative to this embodiment, the piston element 620 can also cancel the setting of the equal-diameter surface 623b, that is, the outer peripheral surface 623 of the piston element 620 is set as a tapered surface 623a or a structure similar to a tapered surface.

[0100] Combination Fig.10 , Fig.11 , Fig.12 In this embodiment, the clutch 400 is arranged on the outer periphery of the optical axis section 230 and its axial direction is arranged along the front-to-back direction. In order to improve work safety, a coupling structure 800 that can be axially clutched is also provided between the clutch 400 and the screw rod 200. In addition, the clutch 400 in this embodiment also has a self-locking function for the screw rod 200. In order to make the screw rod 200 meet the structural requirements, the optical axis section 230 of the screw rod 200 includes a first shaft section 231 and a second shaft section 232. The second shaft section 232 is located behind the first shaft section 231. The rear end of the first shaft section 231 is fixedly connected to the front end of the second shaft section 232. The front end of the second shaft section 232 is inserted into the threaded section 220 to close the rear end of the fluid chamber 210.

[0101] In this embodiment, the clutch 400 is basically axially positioned in the housing 710 through the front positioning seat 730 and the rear positioning seat 740 distributed at intervals along the axial direction. The clutch 400 includes a sun gear 401, a planetary gear 402, a planetary carrier 403, an inner gear ring 404, a brake seat 405, a torque input member 406, a torque output member 407, a retaining ring 408, a brake block 409 and a torsion spring 410. The sun gear 401 is rotatably sleeved on the outside of the first shaft section 231 through a bearing, and the sun gear 401 and the first shaft section 231 are clearance-matched so that the sun gear 401 cannot directly drive the screw rod 200 to rotate. The worm gear 122 is axially positioned and sleeved on the outer periphery of the rear end of the sun gear 401. The worm gear 122 and the sun gear 401 are mutually positioned so that the worm gear 122 can drive the sun gear 401 to rotate. The planet carrier 403 is sleeved on the outside of the front end of the sun gear 401, and the planetary gear 402 is rotatably mounted on the planet carrier 403 and is axially located between the front frame body 4031 and the rear frame body 4032 of the planetary carrier 403. Several planetary gears 402 are arranged at intervals along the circumferential direction, and each planetary gear 402 is meshed with the sun gear 401. The inner gear ring 404 is rotatably sleeved on the outer circumference of all the planetary gears 402 through a bearing, and each planetary gear 402 is meshed with the inner gear ring 404. The brake seat 405 is rotatably mounted in the housing 710, and the front end of the inner gear ring 404 and the rear end of the brake seat 405 are connected by a spline matching structure so that the states of the two can be kept synchronized. The torsion spring 410 is sleeved on the outer periphery of the brake seat 405. The torsion spring 410 has a first twist foot 4101 and a second twist foot. The first twist foot 4101 is connected to the release component 500, and the second twist foot is inserted into the hole on the housing 710 to achieve positioning. The torsion spring 410 holds the brake seat 405 tightly under normal conditions so that the brake seat 405 and the inner gear ring 404 remain fixed under normal conditions. When the operated release component 500 applies force to the first twist foot 4101 to release the torsion spring 410 from the brake seat 405, the brake seat 405 and the inner gear ring 404 are in a rotatable state, so that the lead screw 200 can be released, thereby activating the release function of the linear actuator 10. The torque input member 406 is sleeved on the outside of the first shaft section 231 through a clearance fit. The torque input member 406 is located in front of the planetary carrier 403 and is axially positioned on the inner periphery of the brake seat 405. The rear end of the torque input member 406 is connected to the front frame body 4031 of the planetary carrier 403 through a spline fit structure. Fig.16 The front end of the torque input member 406 is provided with a plurality of input keys 4061 spaced apart along the circumferential direction. Fig.17The torque output member 407 is sleeved on the outer periphery of the first shaft segment 231 and / or the second shaft segment 232 through clearance fit. The torque output member 407 is provided with a plurality of output keys 4071 extending backward and cooperating with the input key 4061. A self-locking angle 4072 is provided on the outer peripheral surface 623 of the torque output member 407. The outer side surface of the self-locking angle 4072 facing away from the axis of the torque output member 407 is roughly an involute arc surface, that is, the self-locking angle 4072 gradually moves away from the axis of the torque output member 407 from one end of the arc to the other end of the arc. Fig.18 The retaining ring 408 is axially positioned and sleeved on the outer circumference of the front end of the torque input member 406 and the rear end of the torque output member 407, and the retaining ring 408 is located on the inner circumference of the brake seat 405. The inner wall of the retaining ring 408 is provided with a plurality of retaining keys 4081 protruding inward and cooperating with the input key 4061, and the retaining ring 408 is circumferentially provided with an arc-shaped groove 4082 for installing the brake block 409. The brake block 409 is in the shape of an arc block and is provided with several pieces at intervals along the circumference. The number of the self-locking angle 4072, the brake block 409, and the arc groove 4082 is consistent and distributed one by one. The brake block 409 is axially positioned at the arc groove 4082 by the limiting ring 411. The brake block 409 can move radially relative to the retaining ring 408 under the interference of the self-locking angle 4072. The brake block 409 pushed outward by the self-locking angle 4072 interferes with the brake seat 405 to achieve friction braking. The brake block 409 released by the self-locking angle 4072 is separated from the brake seat 405 to release the friction braking. Fig.15 The input key 4061, the output key 4071 and the retaining key 4081 are sequentially distributed along the circumferential direction, and the keyway width between two adjacent input keys 4061 is slightly larger than the sum of the key widths of the retaining key 4081 and the output key 4071, so that there can be a certain gap between the two. In the clutch 400, the retaining ring 408, the brake block 409 and the self-locking angle 4072 on the torque output member 407 constitute a self-locking structure.

[0102] Combination Fig.13 , Fig.14In this embodiment, the coupling structure 800 includes a driving coupling 810 and a driven coupling 820. The driving coupling 810 is arranged outside the second shaft section 232 and in front of the torque output member 407 through clearance fit. The driven coupling 820 is sleeved on the outer periphery of the second shaft section 232 through tight fit or non-circular shaft hole fit or spline fit. The driving coupling 810 and the driven coupling 820 adopt a tooth-shaped fit structure that can be axially disengaged. Among them, the driving coupling 810 and the torque output member 407 can be integrally formed, or they can be fixed together after being formed separately, or they can be formed separately and then realize transmission connection through a spline fit structure. In addition, in order to enable the active coupling 810 and the driven coupling 820 to maintain a stable coupling state under normal conditions, the rear end of the first shaft section 231 is sleeved with a first spring 240, and the rear end of the first shaft section 231 is fixed with a positioning plate 250 located behind the first spring 240. The rear end of the first spring 240 is positioned, and the front end of the first spring 240 is against the positioning plate 250. The first spring 240 is in a compressed state and biases the lead screw 200 backwards through the contact with the positioning plate 250. The lead screw 200 biased backwards maintains the engagement tendency of the driven coupling 820 and the active coupling 810.

[0103] Combination Fig. 20 In this embodiment, the release component 500 includes a cable 510, a release link 520, a slide plate 530 and a second spring 540. Two spaced limiting plates 711 are provided on the outer side of the housing 710. The distribution direction of the two limiting plates 711 is perpendicular to the front-to-back direction. The limiting plates 711 are provided with limiting grooves 712 extending a certain length along the front-to-back direction. Both ends of the slide plate 530 are inserted into the limiting grooves 712. The slide plate 530 is slidably arranged relative to the housing 710 in a direction perpendicular to the front-to-back direction (such as the left-right direction). The slide plate 530 is provided with a limiting hole 531 for inserting the first torsion foot 4101 of the torsion spring 410. The slide plate 530 is also provided with a long hole 532 extending obliquely relative to the front-to-back direction. The release link 520 is arranged on the outside of the housing 710 so as to be movable forward and backward. A pin 550 penetrating the long hole 532 is fixed to the rear end of the release link 520. The cable 510 is arranged on the outside of the housing 710 so as to be movable forward and backward. The rear end of the cable 510 is connected to the front end of the release link 520, and the front end of the cable 510 can be operated by the user. The second spring 540 is sleeved on the outside of the rear end of the cable 510. The front end of the second spring 540 is positioned so as to cause the rear end of the second spring 540 to contact the release link 520. The second spring 540 is in a compressed state and biases the release link 520 and the cable 510 backward. Fig. 20 In normal state, under the biasing action of the second spring 540, the torsion spring 410 is in a state of holding the brake seat 405, at which time, the pin 550 is located at the rear end of the long hole 532. Fig.21When the cable 510 is pulled forward, the pulled cable 510 overcomes the biasing effect of the second spring 540 and drives the release link 520 to move forward. The forward-moving release link 520 drives the slide plate 530 to slide relative to the housing 710 through the cooperation between the pin 550 and the long hole 532. The sliding slide plate 530 drives the first torsion foot 4101 of the torsion spring 410 to deflect in the loosening direction. The loosened torsion spring 410 releases the brake seat 405, so that the brake seat 405 is in a rotatable state.

[0104] Under normal conditions, the lead screw 200 is in a coupled state between the driven coupling 820 and the active coupling 810 under the bias of the first spring 240, and the release component 500 is in a loosened state between the first torsion foot 4101 under the bias of the second spring 540. The torsion spring 410 holds the brake seat 405 tightly under normal conditions, that is, the brake seat 405 is in a fixed state under normal conditions, and accordingly, the inner gear ring 404 is also in a fixed state.

[0105] When the actuator is pushed to actuate the load and push it forward, the actuating unit 110 works and drives the sun gear 401 to rotate through the cooperation of the worm 121 and the worm wheel 122. The rotating sun gear 401 drives the torque input member 406 to rotate in the direction indicated by +ω through the planetary gear 402 and the planetary carrier 403. The rotating torque input member 406 drives the torque output member 407 to rotate in the direction indicated by +ω through the interference cooperation between the input key 4061 and the output key 4071. The torque output member 407 that has just started to rotate causes the self-locking angle 4072 to release the brake block 409, and the released brake block 409 moves toward The axis of the retaining ring 408 is close to and radially inward relative to the retaining ring 408, thereby releasing the friction brake between the brake block 409 and the brake seat 405, and then the torque input member 406 drives the torque output member 407, the retaining ring 408 and the brake block 409 to rotate, and the rotating torque output member 407 drives the screw rod 200 to rotate along the direction indicated by +ω through the active coupling 810 and the driven coupling 820, and the rotating screw rod 200 drives the inner tube 310 to move forward through the nut 330, and the inner tube 310 moving forward drives the load to move forward through the front joint 350. The piston rod 610 and the piston element 620 move forward synchronously with the inner tube 310, and the damping fluid 630 in the fluid chamber 210 flows backward from the second chamber 212 through the damping channel 213 toward the first chamber 211. The damping fluid 630 flowing backward acts on the radial pressure-bearing surface RS to make the piston element 620 thinner under pressure, thereby increasing the cross-sectional area of ​​the damping channel 213, and further reducing the damping force of the damping fluid 630 on the tubular telescopic component 300, thereby ensuring the actuation efficiency. When the tubular telescopic component 300 pushes the load to the specified position, the actuating unit 110 stops working. At this time, the screw rod 200 drives the driven coupling 820, the active coupling 810 and the torque output member 407 to rotate a certain angle in the direction shown by -ω under the action of the load pressure. The self-locking angle 4072 that rotates synchronously with the torque output member 407 pushes the brake block 409 outward in the direction away from the axis of the retaining ring 408. The brake block 409 is in a radially outer state relative to the retaining ring 408. The outer brake block 409 contacts the brake seat 405 to achieve friction braking, thereby preventing the screw rod 200 from continuing to rotate, thereby achieving self-locking of the screw rod 200. In this embodiment, a brake ring corresponding to the brake block 409 can also be set on the inner periphery of the brake seat 405, and the brake block 409 contacts the brake ring to achieve friction braking.

[0106] When the actuator is pushed to actuate the load to make the load retreat backward, the actuating unit 110 works and drives the sun gear 405 to rotate in the opposite direction through the cooperation of the worm 121 and the worm wheel 122. The sun gear 401 drives the torque input member 406 to rotate in the direction indicated by -ω through the planetary gear 402 and the planetary carrier 403. The torque input member 406 that has just started to rotate drives the retaining ring 408 to rotate through the interference cooperation between the input key 4061 and the retaining key 4081. The retaining ring 408 drives the brake block 409 to rotate a certain angle so that the brake block 409 is first The self-locking angle 4072 is loosened, thereby releasing the friction brake between the brake block 409 and the brake seat 405, and then the torque input member 406 drives the torque output member 407, the retaining ring 408 and the brake block 409 to rotate together, and the rotating torque output member 407 drives the screw rod 200 to rotate along the direction indicated by -ω through the active coupling 810 and the driven coupling 820, and the rotating screw rod 200 drives the inner tube 310 to move backward through the nut 330, and the inner tube 310 moving backward drives the load to retreat backward through the front joint 350. The self-locking action of the screw rod 200 in this process is the same as the above description, and will not be described here.

[0107] When quick release is required, the user applies force to the cable 510 so that the cable 510 drives the release link 520 to overcome the bias of the second spring 540 and move forward. The forward-moving release link 520 drives the slide plate 530 to slide through the cooperation of the pin 550 and the long hole 532. The sliding slide plate 530 drives the first torsion foot 4101 of the torsion spring 410 to deflect in the loosening direction through the limiting hole 531 so that the torsion spring 410 releases the brake seat 405. The brake seat 405 released by the torsion spring 410 is in a rotatable state, and accordingly, the inner gear ring 404 is also in a rotatable state. Under the action of the load pressure, the screw 200 rotates continuously in the direction indicated by -ω, and the rotating screw 200 drives the torque output member 407 to rotate in the direction indicated by -ω through the driven coupling 820 and the driving coupling 810, and the rotating torque output member 407 drives the retaining ring 408, the brake block 409, the brake seat 405, the torque input member 406, the planet carrier 403, the planetary gear 402, and the inner ring 404 to rotate together, and the sun gear 401 cannot rotate due to the self-locking cooperation of the worm wheel 122 and the worm 121 or the self-locking action of the motor, and the rotation torque caused by the load pressure is released through the rotation of the inner ring 404. The tubular telescopic component 300 retreats quickly under the action of the load pressure, and the purpose of rapid release is achieved without the need for motor actuation. The piston rod 610 and the piston element 620 move from front to back during the release process, and the damping fluid 630 in the fluid chamber 210 flows forward from the first chamber 211 through the damping channel 213 toward the second chamber 212. The damping fluid 630 flowing forward acts on the axial pressure-bearing surface AS to make the piston element 620 thicker under pressure, thereby reducing the cross-sectional area of ​​the damping channel 213, thereby increasing the damping force of the damping fluid 630 on the tubular telescopic component 300, appropriately slowing down the release speed of the tubular telescopic component 300, and avoiding damage caused by the excessively fast release of the tubular telescopic component 300. When the tubular telescopic component 300 retreats to a predetermined position, the cable 510 is released, and the second spring 540 that restores its deformation drives the release link 520 and the cable 510 to move forward. The slide plate 530 returns to its original position to release the first torsion foot 4101, and the torsion spring 410 returns to a state of clamping the brake seat 405, thereby restoring the brake seat 405 and the inner gear ring 404 to a fixed state. The brake block 409 and the brake seat 405 are frictionally braked to stop the screw rod 200 from rotating.

[0108] In the process of the tubular telescopic component 300 actuating the load to retract the load, when other objects are located between the load and the front end of the outer tube 320 and the screw rod 200 encounters resistance in its retraction, the screw rod 200 overcomes the bias of the first spring 240 and moves axially forward relative to the clutch 400. The forward-moving screw rod 200 drives the driven coupling 820 to move synchronously so that the driven coupling 820 disengages from the active coupling 810, thereby blocking the clutch 400 from transmitting the torque to the screw rod 200 through the coupling structure 800, that is, the tubular telescopic component 300 stops actuating when encountering resistance.

[0109] It is understandable that, under the premise of meeting the assembly requirements of the relevant components in the clutch 400, the first shaft segment 231 and the second shaft segment 232 of the optical shaft segment 230 can also be formed in one piece.

[0110] It is understandable that the clutch 400 of this embodiment is designed based on the planetary gear transmission structure, wherein the release component 500 is specifically constructed to pull the torsion spring 410 to act, thereby realizing the release of the power transmission between the planetary gear transmission mechanism and the screw 200. However, the present invention is not limited to this design, and the clutch can also adopt other currently known structures to achieve the function of maintaining or cutting off the power transmission between the actuating unit 110 and the screw 200. For example, the clutch mechanism disclosed in CN214367368U, which is realized by the clutch sleeve and the left connecting member, can be referred to. At this time, the release component activates the release operation by causing the clutch sleeve to move axially; for example, the clutch mechanism disclosed in CN118391414A, which is realized by the clutch sleeve and the worm gear, also triggers the release function by guiding the axial displacement of the clutch sleeve.

[0111] It is understandable that the clutch 400 in this embodiment can also cancel the settings of the retaining ring 408, the brake block 409, the limit ring 411, and the self-locking angle 4072. When the tubular telescopic component 300 drives the load to the specified position through the front joint 350, the self-locking of the screw rod 200 is achieved by utilizing the cooperation between the worm wheel 122 and the worm 121, so that the tubular telescopic component 300 maintains a stable state and prevents the tubular telescopic component 300 from retreating under the action of the load.

[0112] Embodiment 2

[0113] In this embodiment, the linear actuator is a pulling actuator, and the tubular telescopic component pulls the load in a direction close to the actuating unit, that is, the tubular telescopic component pulls the load to move backward. After the release function of the pulling actuator is activated, the tubular telescopic component is released in a direction away from the actuating unit under the action of the load pulling force, that is, after the tubular telescopic component is released, it moves forward rapidly under the action of the load pulling force.

[0114] Combination Fig. 22In this embodiment, the piston element 620 is still arranged at the rear end of the piston rod 610 through the fixing element 640. The piston element 620 is roughly in the shape of a column with a thick front and a thin rear. The front surface of the piston element 620 is the first end surface 621, and the rear surface of the piston element 620 is the second end surface 622. The diameter of the first end surface 621 is slightly larger than the outer diameter of the piston rod 610, and the first end surface 621 constitutes the axial pressure-bearing surface AS. At least part of the outer peripheral surface of the piston element 620 is a tapered surface 623a that gradually deviates from the first end surface 621 to the second end surface 622 toward the axis of the piston element 620. The tapered surface 623a constitutes the radial pressure-bearing surface RS. Accordingly, the cross-sectional area of ​​the damping channel gradually increases from the front to the back. In addition, the outer peripheral surface of the piston element 620 also includes an isodiametric surface located between the tapered surface and the first end surface 621. In this embodiment, the outer circumferential surface 623 of the piston element 620 can also be set to other shapes so that the outer diameter of the radial pressure-bearing surface RS gradually deviates toward the axis of the piston element 620 from the first end surface 621 to the second end surface 622, such as the single-sided cross-sectional shape of the radial pressure-bearing surface RS along the axial direction is set to an arc shape or a broken line shape connected by multiple line segments or other reasonable shapes, so that the outer diameter of the radial pressure-bearing surface RS gradually decreases from front to back; of course, the outer circumferential surface of the piston element 620 can also cancel the setting of the equal-diameter surface.

[0115] Combination Fig. 22 When the actuator is pulled to actuate the load to move backward, the distance the tubular telescopic component moves backward constitutes the working stroke generated by its linear motion along the first direction, that is, the first direction in this embodiment is the backward direction. At this time, the piston rod 610 and the piston element 620 follow the tubular telescopic component to move backward, and the damping fluid in the fluid chamber is squeezed and flows forward from the first chamber 211 through the damping channel 213 toward the second chamber 212. At the same time, the radial pressure-bearing surface RS is located on the pressure-bearing side PS, and the axial pressure-bearing surface AS is located on the back-pressure side BPS. The damping fluid flowing from the back to the front applies pressure to the piston element 620 through the radial pressure-bearing surface RS, and the piston element 620 is subjected to pressure to produce radial inward deformation, that is, the piston element 620 will become thinner under pressure, and the overall shape of the piston element 620 is roughly changed from. Fig. 22 The original state shown by the dotted line is transformed into the thinned state shown by the solid line. The cross-sectional area of ​​the damping channel increases when the piston element 620 is thinned under pressure, thereby appropriately reducing the damping force Fd3 of the damping fluid on the tubular telescopic component.

[0116] Combination Fig.23When the pull actuator activates the release function to make the tubular telescopic component move forward under the action of the load tension Fb2, the distance that the tubular telescopic component moves forward under the load tension Fb2 constitutes the release stroke generated by its linear motion along the second direction, that is, the second direction in this embodiment is the forward direction. At this time, the piston rod 610 and the piston element 620 follow the tubular telescopic component to move forward, and the damping fluid in the fluid chamber is squeezed and flows backward from the second chamber 212 through the damping channel toward the first chamber 211. At the same time, the axial pressure-bearing surface AS is located on the pressure-bearing side PS, and the radial pressure-bearing surface RS is located on the back-pressure side BPS. The damping fluid flowing from front to back applies pressure to the piston element 620 through the axial pressure-bearing surface AS, and the piston element 620 is subjected to pressure and produces radial outward deformation, that is, the piston element 620 becomes thicker under pressure, and the overall shape of the piston element 620 is roughly changed from. Fig.23 The original state shown by the dashed line is transformed into the thickened state shown by the solid line. The cross-sectional area of ​​the damping channel is reduced when the piston element 620 is pressurized and thickened, and the damping fluid flowing in the reverse direction increases the damping force Fd4 on the tubular telescopic component, so that the tubular telescopic component can be slowly released under the action of the load tension.

[0117] The other structures of this embodiment can refer to the first embodiment, but the structures and / or movements of the components such as the brake block 409, the self-locking angle 4072, the retaining ring 408 in the clutch 400 need to be adaptively modified to meet the self-locking requirements of the pull actuator.

[0118] The other structures of the second embodiment are the same as those of the first embodiment and will not be described in detail here.

[0119] Embodiment 3

[0120] In this embodiment, the piston element 620 is roughly cylindrical with equal thickness at the front and back ends and its outer diameter is basically consistent with the inner diameter of the fluid chamber 210. In order to smoothly form the damping channel 213, the piston element 620 is provided with a hole extending from one end face to the other end face, and the damping channel 213 is formed by utilizing the internal space of the hole.

[0121] Combination Fig.24In the push actuator, the hole on the piston element 620 is roughly a tapered hole 625 that is thick at the front and thin at the back. The first end face 621 at the rear end of the piston element 620 constitutes the axial pressure-bearing surface AS, the hole wall of the tapered hole 625 constitutes the radial pressure-bearing surface RS, and the tapered hole 625 constitutes the damping channel 213. When the push actuator actuates the load to move the load forward, the damping fluid in the second chamber flows backward toward the first chamber through the damping channel. At this time, the radial pressure-bearing surface RS is located on the pressure-bearing side PS, and the axial pressure-bearing surface AS is located on the back pressure side BPS. The damping fluid flowing from front to back contacts the radial pressure-bearing surface RS, causing the radial pressure-bearing surface RS to expand outward under force, and the inner diameter of the tapered hole 625 is increased. Correspondingly, the cross-sectional area of ​​the damping channel 213 is increased, so that the damping force of the damping fluid on the tubular telescopic component can be appropriately reduced. When the actuator is pushed to activate the release function so that the tubular telescopic component moves backward under the action of the load pressure, the damping fluid in the first chamber flows forward toward the second chamber through the damping channel. At this time, the axial pressure-bearing surface AS is located on the pressure-bearing side PS, and the radial pressure-bearing surface RS is located on the back-pressure side BPS. The damping fluid flowing from back to front contacts the axial pressure-bearing surface AS to cause the piston element 620 to deform under pressure. The pressure-deformed piston element 620 reduces the inner diameter of the rear end of the tapered hole 625. Correspondingly, the cross-sectional area of ​​the damping channel 213 is reduced, and the damping fluid flowing in the reverse direction increases the release damping force on the tubular telescopic component, thereby allowing the tubular telescopic component to be slowly released under the action of the load pressure.

[0122] Combination Fig.25In the pulling actuator, the hole on the piston element 620 is generally a tapered hole 625 that is thinner at the front and thicker at the back. The first end face 621 at the front end of the piston element 620 constitutes an axial pressure-bearing surface AS, the hole wall of the tapered hole 625 constitutes a radial pressure-bearing surface RS, and the tapered hole 625 constitutes a damping channel 213. When the pulling actuator actuates the load to move the load backward, the damping fluid in the first chamber flows forward toward the second chamber through the damping channel. At this time, the radial pressure-bearing surface RS is located on the pressure-bearing side PS, and the axial pressure-bearing surface AS is located on the back-pressure side BPS. The damping fluid flowing from the back to the front contacts the radial pressure-bearing surface RS, causing the radial pressure-bearing surface RS to expand outward under force, and the inner diameter of the tapered hole 625 is increased. Correspondingly, the cross-sectional area of ​​the damping channel 213 is increased, thereby appropriately reducing the damping force of the damping fluid on the tubular telescopic component. When the release function is activated by pulling the actuator to make the tubular telescopic component move forward under the action of the load tension, the damping fluid in the second chamber flows backward toward the first chamber through the damping channel. At this time, the axial pressure-bearing surface AS is located on the pressure-bearing side PS, and the radial pressure-bearing surface RS is located on the back-pressure side BPS. The damping fluid flowing from back to front contacts the axial pressure-bearing surface AS to cause the piston element 620 to deform under pressure. The pressure-deformed piston element 620 reduces the inner diameter of the front end of the tapered hole 625. Correspondingly, the cross-sectional area of ​​the damping channel 213 is reduced, and the damping fluid 630 flowing in the reverse direction increases the release damping force on the tubular telescopic component 300, thereby allowing the tubular telescopic component to be slowly released under the action of the load pressure.

[0123] It is understandable that the specific shape of the hole on the piston element 620 is not limited to the tapered hole 625 described above, and the hole can also be set to other shapes that meet the damping requirements.

[0124] It is understandable that a tapered groove may be used instead of the tapered hole 625 . The tapered groove is provided on the outer peripheral surface of the piston element 620 and extends from the first end surface 621 to the second end surface 622 . Of course, a combination of a tapered groove and a tapered hole may also be used.

[0125] It is understandable that a plurality of holes on the piston element 620 may be arranged at intervals.

[0126] For other structures of the third embodiment, refer to the first embodiment or the second embodiment.

[0127] Embodiment 4

[0128] In this embodiment, a groove extending in the axial direction is provided on the inner circumferential surface of the fluid chamber, and the groove extends from the inner circumferential surface of the fluid chamber to a certain depth away from the axis of the fluid chamber, and the groove wall cooperates with the outer circumferential surface of the piston element to form a damping channel. In order to make the cross-sectional area of ​​the damping channel adaptively changeable, the outer circumferential surface of the piston element can be set to a corresponding conical shape according to the type of the linear actuator, and the maximum outer diameter of the piston element can be substantially consistent with the inner diameter of the fluid chamber.

[0129] In the push actuator, the cross-sectional area of ​​the damping channel formed by the groove wall of the groove and the outer peripheral surface of the piston element is gradually reduced from the front to the rear.

[0130] In the pulling actuator, the cross-sectional area of ​​the damping channel formed by the groove wall of the groove and the outer peripheral surface of the piston element is gradually increased from the front to the rear.

[0131] It can be understood that the groove in the fourth embodiment can be combined with the hole on the piston element in the third embodiment to form a damping channel.

[0132] It can be understood that, in this embodiment, a plurality of grooves on the inner circumferential surface of the fluid chamber can be arranged at intervals along the circumferential direction.

[0133] For other structures of the fourth embodiment, refer to the first embodiment or the second embodiment.

[0134] In addition to the above preferred embodiments, the present invention has other implementation modes. Those skilled in the art may make various changes and modifications based on the present invention. As long as they do not depart from the spirit of the present invention, they should all fall within the scope defined in the claims of the present invention.

Claims

1. A linear actuator with safety release, comprising: an actuating unit providing an actuating torque; A lead screw driven to rotate by an actuating torque; A tubular telescopic component is sleeved outside the screw and driven by the rotational motion of the screw to perform linear telescopic motion; A clutch, which is used to maintain or cut off the power transmission between the actuating unit and the screw rod; An operable release component that drives the clutch to cut off power transmission between the actuation unit and the lead screw to activate a release function of the linear actuator; Characterized in that the linear actuator also includes: A fluid chamber axially extending inside the screw and filled with a damping fluid, the fluid chamber having a first end close to the actuating unit and a second end away from the actuating unit; A piston rod inserted into the fluid chamber, which is connected to the tubular telescopic component, wherein the portion of the piston rod inserted into the fluid chamber is provided with a piston element, and the fluid chamber is divided into a first chamber between the piston element and the first end and a second chamber between the piston element and the second end; a damping passage, disposed inside the fluid chamber and allowing the damping fluid to flow through the piston element to communicate with the first chamber and the second chamber; After the linear actuator activates the release function, the damping fluid is restricted to flow through the damping channel to provide a damping force to resist the load force.

2. The linear actuator with safety release as claimed in claim 1, characterized in that: The linear actuator is configured as a push actuator, and the tubular telescopic component pushes the load in a direction away from the actuator unit. After the linear actuator activates the release function, the tubular telescopic component is released in a direction close to the actuator unit under the thrust of the load, and the damping fluid in the first chamber flows through the damping channel in a restricted manner into the second chamber, providing a damping force to counteract the load thrust.

3. The linear actuator with safety release as claimed in claim 1, characterized in that: The linear actuator is configured as a pulling actuator, and the tubular telescopic component pulls the load in a direction close to the actuating unit. After the linear actuator activates the release function, the tubular telescopic component is released in a direction away from the actuating unit under the load pulling force, and the damping fluid in the second chamber flows through the damping channel in a restricted manner into the first chamber, providing a damping force to counteract the load pulling force.

4. The linear actuator with safety release as claimed in claim 1, characterized in that: The linear movement of the tubular telescopic component in a first direction is defined as a working stroke, and the linear movement of the tubular telescopic component in a second direction opposite to the first direction under a load force is defined as a release stroke. The cross-sectional area of ​​at least part of the damping channel is variable, so that the cross-sectional area of ​​this part of the damping channel in the working stroke of the tubular telescopic component is larger than that in the release stroke.

5. The linear actuator with safety release as claimed in claim 4, characterized in that: The damping channel is formed by at least a partial reserved gap between the portion of the inner circumference of the fluid chamber corresponding to the piston element and the outer circumference of the piston element. The piston element undergoes reversible radial deformation under the pressure of the damping fluid to change the cross-sectional area of ​​the damping channel.

6. The linear actuator with safety release as claimed in claim 5, characterized in that: A circumferentially continuous damping channel is formed between a portion of the inner circumferential surface of the fluid chamber corresponding to the piston element and an outer circumferential surface of the piston element.

7. The linear actuator with safety release as claimed in claim 5, characterized in that: The piston element has a radial pressure-bearing surface and an axial pressure-bearing surface; During the working stroke of the tubular telescopic component, the radial pressure-bearing surface is located on the pressure-bearing side of the piston element, and bears the radial pressure of the damping fluid to cause the piston element to deform radially inward, and the axial pressure-bearing surface is located on the back-pressure side of the piston element; During the release stroke of the tubular telescopic component, the axial pressure-bearing surface is located on the pressure-bearing side of the piston element, and bears the axial pressure of the damping fluid to cause the piston element to deform radially outward, and the radial pressure-bearing surface is located on the back-pressure side of the piston element.

8. The linear actuator with safety release as claimed in claim 6, characterized in that: The piston element comprises a first end face and a second end face which are axially separated, the outer peripheral surface of the piston element is connected between the first end face and the second end face, and the axial extension direction from the first end face to the second end face is defined to be consistent with the first direction; At least part of the first end surface of the piston element constitutes the axial pressure-bearing surface; At least part of the outer circumference of the piston element constitutes a radial pressure-bearing surface, and this part of the outer circumference gradually deviates toward the axis of the piston element along the first direction, and the cross-sectional area of ​​the part of the damping channel corresponding to the radial pressure-bearing surface increases unidirectionally along the first direction.

9. The linear actuator with safety release as claimed in claim 7, characterized in that: Part of the outer peripheral surface of the piston element forms an equal-diameter surface, and the equal-diameter surface is located between the axial pressure-bearing surface and the radial pressure-bearing surface.

10. The linear actuator with safety release as claimed in claim 5, characterized in that: The linear actuator also includes a fixing element, which includes a connecting portion, a limiting portion and a supporting portion located therebetween, the connecting portion passing through the piston element and connected to the insertion end of the piston rod, the piston element is axially clamped and limited by the insertion end of the piston rod and the limiting portion, and the supporting portion axially penetrates the piston element for its centering and support.

11. The linear actuator with safety release as claimed in claim 10, characterized in that: The connection between the connecting portion and the insertion end of the piston rod is configured as a threaded fitting connection; and / or the connection between the limiting portion and the supporting portion is configured as a threaded fitting connection.

12. The linear actuator with safety release as claimed in claim 1, characterized in that: The first end of the fluid chamber is a closed end, and the second end provides an opening for inserting the piston rod. A sealing element is arranged at the opening to provide a dynamic seal between the second end and the piston rod.

13. The safety release linear actuator of claim 1, wherein: The damping passage comprises a hole extending axially through the piston element; and / or the damping passage comprises a groove extending axially on the inner circumferential surface of the fluid chamber.

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