Secure release linear actuator

Abstract

The utility model discloses a safely released linear actuator, which belongs to the technical field of actuating equipment and comprises an actuating unit, a screw rod, a tubular telescopic component, a clutch, an operable release component and a fluid chamber, the tubular telescopic component does linear telescopic motion, the fluid chamber 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] This utility model relates to the field of actuation equipment technology, and in particular to a safe-release linear actuator. Background Technology

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

[0003] Considering the application scenarios of linear actuators, when a linear actuator needs to cut off power due to motor failure or power outage, a clutch structure and an operable release component are typically added to facilitate the smooth retraction of the tubular telescopic component. The clutch structure maintains or cuts off the power transmission between the actuator unit and the lead screw. Operating the release component cuts off the power transmission between the actuator unit and the lead screw, activating the release function. This causes the lead screw to rotate under load, rapidly retracting the tubular telescopic component for release. The greater the load, the faster the release speed of the tubular telescopic component. When linear actuators are used as push actuators on electric beds, excessively fast release speeds can easily cause injury to patients. When linear actuators are used as pull actuators in lifting applications, heavier loads accelerate the release speed, potentially causing damage to the load, people, or objects below the load. Utility Model Content

[0004] To address the shortcomings and deficiencies in the existing technology, this invention provides a safe-release linear actuator. Through structural improvements, it effectively slows down the release speed of the tubular telescopic component while slightly sacrificing actuation efficiency, thereby achieving an effective balance between actuation efficiency and operational safety and improving the safety performance of the product.

[0005] To achieve the above technical objectives, the present invention provides a safe-release linear actuator, comprising:

[0006] An actuation unit that provides actuating torque;

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

[0008] A tubular telescopic component, which is fitted outside a lead screw and driven by the rotational motion of the lead screw to perform linear telescopic motion;

[0009] A clutch for maintaining or cutting off power transmission between an actuating unit and a screw rod;

[0010] A release component operable to drive the clutch to cut off power transmission between the actuating unit and the screw rod to activate a release function of the linear actuator;

[0011] The linear actuator further comprises:

[0012] A fluid chamber axially extending inside the screw rod and filled with damping fluid, 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 and connected to the tubular telescopic component, a piston element being arranged on the portion of the piston rod inserted into the fluid chamber, the fluid chamber being 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 provided inside the fluid chamber and allowing the damping fluid to flow through the piston element to communicate the first chamber and the second chamber;

[0015] When the linear actuator activates the release function, the damping fluid is limited to flow through the damping passage to provide a damping force against the load force.

[0016] Further, the linear actuator is configured to push the actuator, the tubular telescopic component pushes the load away from the actuating unit, when the linear actuator activates the release function, the tubular telescopic component is released to move towards the actuating unit, the damping fluid in the first chamber is limited to flow through the damping passage into the second chamber to provide a damping force against the load force.

[0017] Further, the linear actuator is configured to pull the actuator, the tubular telescopic component pulls the load towards the actuating unit, when the linear actuator activates the release function, the tubular telescopic component is released to move away from the actuating unit, the damping fluid in the second chamber is limited to flow through the damping passage into the first chamber to provide a damping force against the load force.

[0018] Further, a linear movement of the tubular telescopic component in a first direction is defined as a working stroke, a linear movement of the tubular telescopic component in a second direction opposite to the first direction under the load force is defined as a release stroke, at least a portion of the damping passage has a variable cross-sectional area, the portion of the damping passage provides a larger cross-sectional area in the working stroke than in the release stroke.

[0019] Further, a gap is formed between the inner circumferential surface of the fluid chamber corresponding to the piston element and the outer circumferential surface of the piston element, and the gap constitutes the damping passage.

[0020] Further, a circumferentially continuous damping passage is formed between the inner circumferential surface of the fluid chamber corresponding to the piston element and the 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 at 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 inwardly, and the axial pressure bearing surface is located at 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 at 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 outwardly, and the radial pressure bearing surface is located at the back pressure side of the piston element.

[0024] Further, the piston element comprises an axially spaced first end surface and a second end surface, and the outer circumferential surface of the piston element is connected between the first end surface and the second end surface, and the axial extension direction from the first end surface to the second end surface is 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 circumferential surface of the piston element constitutes the radial pressure bearing surface, and this part of the outer circumferential surface gradually deviates from the axial center of the piston element along the first direction, and the cross-sectional area of the part of the damping passage corresponding to the radial pressure bearing surface unidirectionally increases along the first direction.

[0027] Further, part of the outer circumferential surface of the piston element constitutes an equidiameter surface, and the equidiameter surface is located between the axial pressure bearing surface and the radial pressure bearing surface.

[0028] Further, the linear actuator further comprises a fixing element, the fixing element comprises a connecting portion, a limiting portion and a supporting portion located therebetween, the connecting portion is connected to the insertion end of the piston rod through the piston element, 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 centering and supporting thereof.

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

[0030] Further, the first end of the fluid chamber is a closed end, and the second end provides an opening for insertion of the piston rod, and a sealing element is arranged at the opening to provide dynamic sealing between the second end and the piston rod.

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

[0032] After the above technical scheme, the utility model has the advantages of:

[0033] 1. The linear actuator provided by the utility model sets a fluid chamber extending in the axial direction and filled with damping fluid inside the screw rod, a piston rod is inserted into the fluid chamber and connected to the tubular telescopic part, and a piston element arranged on the piston rod divides the fluid chamber into a first chamber and a second chamber that can be communicated through a damping channel.

[0034] When the linear actuator is activated and released, the tubular telescopic part moves linearly under the action of the load and has a certain release speed, the piston rod moves linearly in the fluid chamber along with the tubular telescopic part, and the damping fluid in the fluid chamber flows reversely relative to the piston rod, and because the reversely flowing damping fluid is limited to flow through the damping channel, the reversely flowing damping fluid causes the tubular telescopic part to bear a damping force opposite to the load force, and the damping force can effectively slow down the release speed of the tubular telescopic part, avoiding the safety risks or damages caused by the release of the tubular telescopic part under the action of the load force.

[0035] When the actuating unit actuates the load through the screw rod and the tubular telescopic part, the linearly moving tubular telescopic part drives the load to move synchronously, at this time, the piston rod moves linearly in the fluid chamber along with the tubular telescopic part, and the damping fluid in the fluid chamber also flows reversely relative to the piston rod, and because the reversely flowing damping fluid is limited to flow through the damping channel, the reversely flowing damping fluid causes the tubular telescopic part to bear a damping force opposite to the direction of the actuating force, which slows down the actuating speed of the tubular telescopic part on the load.

[0036] Although the damping structure composed of the piston rod, the piston element, the damping channel and the damping fluid can slow down the actuating speed of the tubular telescopic part on the load, the damping structure can also effectively slow down the release speed of the tubular telescopic part under the action of the load, avoiding the safety risks or damages caused by the excessive release speed, and by slightly sacrificing the actuating efficiency, the release speed of the tubular telescopic part is effectively slowed down, so that the actuating efficiency and the working safety are effectively balanced, which is beneficial to improving the safety performance of the product.

[0037] 2、When the linear actuator is configured as a push actuator, after the release function is activated, the tubular telescopic member is released under the action of the pushing force of the load towards the actuating unit, the piston rod moves in the fluid chamber towards the actuating unit, at this time, the damping fluid in the first chamber flows through the damping passage towards the second chamber under restriction, the damping fluid flowing in the opposite direction to the piston rod makes the tubular telescopic member bear a damping force against the pushing force of the load, so as to slow down the release speed of the tubular telescopic member and the load.

[0038] 3、When the linear actuator is configured as a pull actuator, after the release function is activated, the tubular telescopic member is released under the action of the pulling force of the load away from the actuating unit, the piston rod moves in the fluid chamber away from the actuating unit, at this time, the damping fluid in the second chamber flows through the damping passage towards the first chamber under restriction, the damping fluid flowing in the opposite direction to the piston rod makes the tubular telescopic member bear a damping force against the pulling force of the load, so as to slow down the release speed of the tubular telescopic member and the load.

[0039] 4、The cross-sectional area of at least part of the damping passage is preferably variable, the part of the damping passage provides a larger cross-sectional area in the working stroke of the tubular telescopic member than in the release stroke, the change of the cross-sectional area of the damping passage increases the reverse flow of the damping fluid when the tubular telescopic member is actuated, and appropriately reduces the actuating damping force of the damping fluid flowing in the opposite direction to the tubular telescopic member, which is conducive to ensuring the actuating efficiency of the tubular telescopic member. The release damping force of the damping structure on the tubular telescopic member is improved, and the actuating damping force on the tubular telescopic member is minimized at the same time.

[0040] 5、The at least partial clearance between the inner circumferential surface of the fluid chamber and the outer circumferential surface of the piston element constitutes the damping passage, when the damping fluid flows in the opposite direction to the piston rod, the pressure of the damping fluid causes the piston element to reversibly deform radially. The greater the load force borne by the tubular telescopic member, the greater the pressure of the damping fluid on the piston element, the greater the radial deformation of the piston element, the narrower the damping passage, the smaller the flow of the damping fluid, and the greater the damping force of the damping fluid on the tubular telescopic member. The radial deformation of the piston element changes the cross-sectional area of the damping passage, so that the cross-sectional area of the damping passage can be adaptively changed according to the size of the load force, so that the tubular telescopic member can obtain a substantially consistent release speed under the action of different load forces. The greater the load force, the smaller the cross-sectional area of the damping passage, and the greater the damping force of the damping fluid on the tubular telescopic member.

[0041] 6. The damping channel is preferably arranged continuously along the circumference. A reasonable design of the damping channel shape maximizes 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. This further enhances the release damping force exerted on the tubular telescopic component by the damping fluid. Whether in the working stroke or the release stroke, the piston rod moves synchronously with the tubular telescopic component. A reasonable piston element shape helps achieve uniform pressure distribution; for example, using symmetrical cylindrical or spherical designs. This invention optimizes the layout and shape of the damping channel, allowing the damping fluid to flow uniformly around the piston element, thus generating a uniform pressure distribution. This helps 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 bearing surface of the piston element is located on the bearing side of the piston element, and the axial bearing surface of the piston element is located on the back pressure side of the piston element. The damping fluid flowing in the opposite direction to the tubular telescopic component directly acts on the radial bearing surface, causing the piston element to be subjected to radial pressure. The piston element bearing the radial pressure undergoes radial inward deformation, that is, the piston element becomes thinner under pressure. Correspondingly, the cross-sectional area of ​​the damping channel increases, and the damping fluid flowing in the opposite direction can flow smoothly, thereby reducing the actuation damping of the tubular telescopic component and ensuring the actuation efficiency of the tubular telescopic component.

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

[0044] 8. At least a portion of the outer peripheral surface of the piston element constitutes a radial bearing surface, which gradually deviates towards the axis along the first direction. Preferably, the radial bearing surface is a conical structure. Correspondingly, the cross-sectional area of ​​the portion of the damping channel corresponding to the radial bearing surface increases along the first direction. By rationally setting the shape of the radial bearing surface, the outer diameter of the axial bearing surface is increased, thereby increasing the contact area between the counter-flowing damping fluid and the piston element when the tubular telescopic component releases, increasing the axial pressure on the piston element, and further reducing the cross-sectional area of ​​the damping channel. This further increases the release damping of the tubular telescopic component caused by the counter-flowing damping fluid. Furthermore, because the radial bearing surface is conical, the radial pressure on the piston element when the tubular telescopic component is actuated by the damping fluid can be increased. This allows the narrower piston element to effectively increase the cross-sectional area of ​​the damping channel, further reducing the actuation damping of the tubular telescopic component caused by the counter-flowing damping fluid, ensuring the actuation efficiency of the tubular telescopic component.

[0045] 9. Preferably, a portion of the outer circumferential surface of the piston element is configured as an equal-diameter surface located between the axial bearing surface and the radial bearing surface. This equal-diameter surface ensures that the maximum outer diameter of the piston element remains essentially stable during radial deformation when it is subjected to axial pressure (when it becomes thicker) or radial pressure (when it becomes thinner). Consequently, the minimum cross-sectional area of ​​the damping channel remains essentially stable during radial deformation of the piston element. This allows the tubular telescopic component to experience stable damping during release or actuation, preventing the tubular telescopic component from moving erratically due to fluctuating damping and improving its motion stability.

[0046] 10. The piston element is connected to the piston rod using a fixing element. At the same time, the support part of the fixing element is used to center and support the piston element, ensuring the structural stability of the piston element and improving the stability of the damping effect of the damping structure on the release damping of the tubular telescopic component. Attached Figure Description

[0047] Figure 1 This is an overall diagram of the linear actuator in Example 1;

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

[0049] Figure 3 This is an axial sectional view of the tubular telescopic component and the lead screw in Embodiment 1;

[0050] Figure 4 This is a partial structural diagram of the lead screw in Example 1;

[0051] Figure 5 This is a structural diagram of the piston rod, piston element, and fixing element in Embodiment 1;

[0052] Figure 6 Axial sectional view of the piston element in Example 1;

[0053] Figure 7 Structure view of the fixed element in Example 1;

[0054] Figure 8 Partial structure view of the inside of the screw rod when the push actuator is pushing the load in Example 1;

[0055] Figure 9 Partial structure view of the inside of the screw rod when the push actuator is activated to release the function in Example 1;

[0056] Figure 10 Axial sectional view of the casing, clutch, screw rod and coupling structure in Example 1;

[0057] Figure 11 Axial sectional view of the clutch, screw rod and coupling structure in Example 1;

[0058] Figure 12 Exploded view of the clutch, screw rod and coupling structure in Example 1;

[0059] Figure 13 Matching view of the partial structure of the clutch, screw rod and coupling structure in Example 1;

[0060] Figure 14 Matching view of another partial structure of the clutch, screw rod and coupling structure in Example 1;

[0061] Figure 15 Radial sectional view of the partial structure of the clutch in Example 1;

[0062] Figure 16 Structure view of the torque input in Example 1;

[0063] Figure 17 Structure view of the torque output in Example 1;

[0064] Figure 18 Exploded view of the retaining ring and brake block in Example 1;

[0065] Figure 19 Structure view of the partial structure of the clutch, screw rod and coupling structure when the coupling structure is separated in Example 1;

[0066] Figure 20 Partial structure view of the release component in normal state in Example 1;

[0067] Figure 21 Partial structure view of the release component when activated to release the function in Example 1;

[0068] Figure 22 Partial structure diagram of the inside of the lead screw when the pull actuator in Example 2 is pulling a load;

[0069] Figure 23 Partial structure diagram of the inside of the lead screw when the pull actuator in Example 2 is activated to release;

[0070] Figure 24 Axial sectional view of the piston element applied to the push actuator in Example 3;

[0071] Figure 25 Axial sectional view of the piston element applied to the pull actuator in Example 3.

[0072] In the drawings, 10 - linear actuator, 110 - actuation unit, 120 - transmission structure, 121 - worm, 122 - worm wheel, 200 - lead screw, 210 - fluid chamber, 211 - first chamber, 212 - second chamber, 213 - damping passage, 220 - threaded section, 230 - optical axis section, 231 - first shaft section, 232 - second shaft section, 240 - first spring, 250 - positioning piece, 300 - tubular telescopic part, 310 - inner tube, 320 - outer tube, 330 - nut, 340 - end cap, 350 - front joint, 360 - sealing element, 400 - clutch, 401 - sun gear, 402 - planet gear, 403 - planet carrier, 4031 - front carrier body, 4032 - rear carrier body, 404 - inner ring gear, 405 - brake seat, 406 - torque input, 4061 - input key, 407 - torque output, 4071 - output key, 4072 - self-locking angle, 408 - retaining ring, 4081 - retaining key, 4082 - arc-shaped groove, 409 - brake block, 410 - torsion spring, 4101 - first torsion leg, 411 - limiting ring, 500 - release part, 510 - pull cable, 520 - release link, 530 - sliding plate, 531 - limiting hole, 532 - long hole, 540 - second spring, 550 - pin post, 610 - piston rod, 620 - piston element, 621 - first end face, 622 - second end face, 623 - outer peripheral face, 623a - conical face, 623b - constant-diameter face, 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 - driving 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] It is to be understood that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "vertical", "horizontal", "top", "bottom" and other similar terms indicating orientation or positional relationships as used herein are based on the orientation or positional relationships shown in the drawings and are used only for the purpose of describing the present application and simplifying the description, and do not indicate or imply that the device / element referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0074] Embodiment one

[0075] In combination Figures 1 to 21 The safety release linear actuator 10 provided by the embodiment one of the present application comprises:

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

[0077] A screw rod 200 driven to rotate by the actuation torque;

[0078] A tubular telescopic member 300 sleeved on the screw rod 200 and driven to perform linear telescopic movement by the rotational movement of the screw rod 200;

[0079] A clutch 400 for maintaining or cutting off the power transmission between the actuation unit 110 and the screw rod 200;

[0080] A release member 500 operable to drive the clutch 400 to cut off the power transmission between the actuation unit 110 and the screw rod 200 and activate the release function of the linear actuator 10;

[0081] The linear actuator 10 further comprises:

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

[0083] A piston rod 610 inserted into the fluid chamber 210 and connected to the tubular telescopic member 300, the part of the piston rod 610 inserted into the fluid chamber 210 being configured as a piston element 620, the fluid chamber 210 being 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] A damping passage 213 provided inside the fluid chamber 210 and allowing the damping fluid 630 to flow through the piston element 620 to communicate the first chamber 211 and the second chamber 212;

[0085] When the linear actuator 10 is activated to release, the tubular telescopic component 300 is linearly moved under the action of the load and has a certain release speed, the piston rod 610 is linearly moved in the fluid chamber 210 following the tubular telescopic component 300, the damping fluid 630 in the fluid chamber 210 flows reversely relative to the piston rod 610, and the damping fluid 630 flowing reversely is limited to flow through the damping passage 213, so that the tubular telescopic component 300 is subjected to a damping force opposite to the load force, and the release speed of the tubular telescopic component 300 is effectively slowed down through the damping force, so as to avoid the safety risk or damage caused by the release of the tubular telescopic component 300 under the action of the load force.

[0086] When the linear actuator 10 is activated to release, the tubular telescopic component 300 is linearly moved under the action of the load and has a certain release speed, the piston rod 610 is linearly moved in the fluid chamber 210 following the tubular telescopic component 300, the damping fluid 630 in the fluid chamber 210 flows reversely relative to the piston rod 610, and the damping fluid 630 flowing reversely is limited to flow through the damping passage 213, so that the tubular telescopic component 300 is subjected to a damping force opposite to the load force, and the release speed of the tubular telescopic component 300 is effectively slowed down through the damping force, so as to avoid the safety risk or damage caused by the release of the tubular telescopic component 300 under the action of the load force.

[0087] In combination Figure 1 , Figure 2 In the embodiment, the linear actuator 10 further comprises a housing 710, and the clutch 400 and other structures 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 left-right split shell structure, and the left and right two 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 is matched with a worm gear 122. The worm 121 is in transmission connection or integrally formed with the rotating shaft of the motor, the worm gear 122 is engaged with the worm 121, the worm gear 122 is rotatably arranged in the housing 710 and the axial direction of the worm gear 122 is basically along the front-back direction. The motor outputs an actuating torque outward through the transmission structure 120, and the rotating worm gear 122 can drive the lead screw 200 to rotate through the clutch 400. Of course, the transmission structure 120 can also adopt a gear matching structure or other structures meeting the power transmission requirements.

[0088] In the embodiment, the length direction of the tubular telescopic component 300 is arranged along the front-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. In combination Figure 3The tubular telescopic component 300 comprises an inner tube 310, an outer tube 320, a nut 330 and the like. Specifically, the nut 330 is sleeved on the outer periphery of the lead screw 200 through thread cooperation, the inner tube 310 is sleeved on the outer periphery of the lead screw 200 with a space therebetween and is fixedly sleeved on the outer periphery of the nut 330 at the rear end thereof, the outer tube 320 is sleeved on the outer periphery of the inner tube 310 with a space therebetween, the rear end of the outer tube 320 is fixedly attached to the cabinet 710, the front end of the outer tube 320 is provided with an end cover 340, the front end of the inner tube 310 protrudes out of the end cover 340 and is provided with a front connector 350, and the rear end of the cabinet 710 is provided with a rear connector 720. The load is connected to the inner tube 310 of the tubular telescopic component 300 through the front connector 350, and the inner tube 310 is driven by the nut 330 to move linearly in the front-rear direction when the lead screw 200 rotates, and the load is synchronously moved by the inner tube 310 through the front connector 350. Optionally, the linear actuator 10 as a whole can be fixedly connected or rotatably connected to other objects through the rear connector 720.

[0089] In this embodiment, the lead screw 200 comprises thread segments 220 and optical axis segments 230 which are distributed in front and back and connected to each other. The thread segments 220 of the lead screw 200 are hollow and tubular, and an elongated fluid chamber 210 is formed in the hollow inner cavity of the thread segments 220. The front end of the optical axis segment 230 is inserted into the rear end of the thread segment 220 to close the rear end of the fluid chamber 210. The front end of the hollow tubular thread segment 230 has an opening for the piston rod 610 to be inserted into, and the piston rod 610 is inserted into the fluid chamber 210 from front to back. The front end of the piston rod 610 protrudes out of the thread segment 220 and is connected to the front connector 350 through a fastener. The front end of the piston rod 610 is the protruding end thereof, and the rear end of the piston rod 610 is the inserted end thereof. The front end of the lead screw 200 is fixedly provided with a sealing element 360 which is sleeved on the outer periphery of the piston rod 610 through clearance cooperation and is inserted into the opening at the front end of the thread segment 220. The sealing element 360 and the piston rod 610 and the sealing element 360 and the inner tube 310 are circumferentially sealed through sealing rings. The sealing element 360 and the sealing rings provide dynamic sealing cooperation between the piston rod 610 and the lead screw 200, and the sealing element 360 also closes the front end of the fluid chamber 210, so that the fluid chamber 210 is a closed chamber and the damping fluid 630 is prevented from leaking outwards. 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 hydraulic oil or other liquid with certain viscosity, or can be pressurized gas, as long as the damping requirement is met, and no more limitation is made herein.

[0090] In combination with Figure 4 , Figure 5In the embodiment, the piston element 620 is arranged at the rear end of the piston rod 610 by the fixing element 640, the part of the fluid chamber 210 between the piston element 620 and the front end of the optical axis segment 230 constitutes the first chamber 211, the part of the fluid chamber 210 between the piston element 620 and the sealing element 360 constitutes the second chamber 212, and the part of the fluid chamber 210 corresponding to the piston element 620 constitutes the damping passage 213. The first chamber 211, the damping passage 213 and the second chamber 212 are arranged in sequence from rear to front, and the first chamber 211 and the second chamber 212 can be communicated through the damping passage 213.

[0091] The piston rod 610, the piston element 620, the damping fluid 630 and the damping passage 213 constitute a damping structure for slowing down the release movement speed of the tubular telescopic component 300. The damping structure is specifically described by taking the push actuator as an example. In the push actuator, the tubular telescopic component 300 can push the load away from the actuating unit 110 through the front joint 350, and the linear movement of the tubular telescopic component 300 in the forward direction is the 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 push actuator activates the release function, the tubular telescopic component 300 is released towards the actuating unit 110 under the action of the load, and the linear movement of the tubular telescopic component 300 in the backward direction 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 flows towards the second chamber 212 through the damping passage 213, that is, the damping fluid 630 flows reversely relative to the piston rod 610 and the piston element 620 moving backward, and the reversely flowing damping fluid 630 provides the damping force against the load pressure.

[0092] In combination with Figure 4In the 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 circumferential surface 623 of the piston element 620 and the inner circumferential surface of the fluid chamber 210 forms the damping passage 213. Since the cross-sectional area of the damping passage 213 affects the flow rate of the damping fluid 630, which in turn affects the damping force of the damping fluid 630 on the tubular telescopic component 300, in order to adaptively change the cross-sectional area of the damping passage 213 according to the size of the load force, the piston element 620 can reversibly deform when subjected to the pressure of the damping fluid 630, and the cross-sectional area of the damping passage 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 different load forces. Specifically, the piston element 620 in the embodiment is in a columnar shape and its axial direction is arranged along the front-rear direction, and the reserved gap between the outer circumferential surface 623 of the piston element 620 and the inner circumferential surface of the fluid chamber 210 is preferably continuously arranged along the circumferential direction, and correspondingly, the damping passage 213 is also continuously arranged along the circumferential direction, i.e., the damping passage 213 is in an annular shape. In combination with Figure 6 The piston element 620 includes a first end surface 621 at the rear end, a second end surface 622 at the front end, and an outer circumferential surface 623 between the first end surface 621 and the second end surface 622, the first end surface 621 and the second end surface 622 are spaced apart along the axial direction, and the outer circumferential surface 623 of the piston element 620 is connected between the first end surface 621 and the second end surface 622. As an alternative to the embodiment, the damping passage 213 can also be discontinuously arranged along the circumferential direction by changing the shape of the piston element, or the cross-sectional shape of the damping passage 213 perpendicular to the axial direction is in an arc shape or other reasonable shape.

[0093] In the embodiment, the piston element 620 is provided with a through hole 624 cooperating with the fixing element 640, and the fixing element 640 passes through the through hole 624 and is connected to the rear end of the piston rod 610. In combination with Figure 7The fixing element 640 comprises 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. The outer diameter of the limiting portion 643 is larger than the hole diameter 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. Further, the rear end of the piston rod 610 can be provided with a threaded hole. The connecting portion 641 is connected to the rear end of the piston rod 610 by threaded cooperation. In this way, 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, so as to adjust the position of the limiting portion 643 relative to the piston element 620, and ensure 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 cooperation, which is not limited 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 connected together after being formed in parts. Of course, the connecting portion 641 and the supporting portion 642 can be integrally formed, and the limiting portion 643 is connected to the rear end of the supporting portion 642 by threaded cooperation. At this time, the position of the limiting portion 643 relative to the piston element 620 can be adjusted by threaded cooperation according to the axial length of the piston element 620, so as to ensure the limiting effect of the limiting portion 643 on the piston element 620.

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

[0095] In combination Figure 8, the tubular telescopic member 300 is pushed by the load to move forward, the distance of the forward movement of the tubular telescopic member 300 constitutes the working stroke generated by the linear movement of the tubular telescopic member 300 in the first direction, and 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, the damping fluid 630 in the fluid chamber 210 is extruded and flows from the front second chamber 212 to the rear first chamber 211, that is, the damping fluid 630 flows reversely relative to the piston rod 610. At the same time, the radial pressure side RS is located at the pressure side PS of the piston element 620, and the axial pressure side AS is located at the back pressure side BPS of the piston element 620. In order to reduce the damping force Fd1 of the damping fluid 630 flowing reversely on the tubular telescopic member 300 as much as possible, the piston element 620 preferably deforms radially inward under the pressure of the damping fluid 630, that is, the piston element 620 is thin under pressure, and correspondingly, the cross-sectional area of the damping channel 213 is larger, so that the damping force Fd1 of the damping fluid 630 flowing reversely on the tubular telescopic member 300 is reduced, thereby ensuring the actuating efficiency of the tubular telescopic member 300.

[0096] In combination Figure 9 , the tubular telescopic member 300 is pushed by the load to move forward, the distance of the forward movement of the tubular telescopic member 300 constitutes the working stroke generated by the linear movement of the tubular telescopic member 300 in the first direction, and 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, the damping fluid 630 in the fluid chamber 210 is extruded and flows from the front second chamber 212 to the rear first chamber 211, that is, the damping fluid 630 flows reversely relative to the piston rod 610. At the same time, the radial pressure side RS is located at the pressure side PS of the piston element 620, and the axial pressure side AS is located at the back pressure side BPS of the piston element 620. In order to reduce the damping force Fd1 of the damping fluid 630 flowing reversely on the tubular telescopic member 300 as much as possible, the piston element 620 preferably deforms radially inward under the pressure of the damping fluid 630, that is, the piston element 620 is thin under pressure, and correspondingly, the cross-sectional area of the damping channel 213 is larger, so that the damping force Fd1 of the damping fluid 630 flowing reversely on the tubular telescopic member 300 is reduced, thereby ensuring the actuating efficiency of the tubular telescopic member 300.

[0097] In order to enable the piston element 620 to adaptively deform according to the movement state of the tubular telescopic component 300, in the embodiment, the piston element 620 is substantially columnar with a front thin and rear thick shape, and correspondingly, the outer circumferential surface 623 of the piston element 620 has a tapered surface 623a with a front thin and rear thick shape, which constitutes the radial pressure-bearing surface RS. In combination with Figure 8 , when the tubular telescopic component 300 is normally actuated to bear a load, the piston rod 610 and the piston element 620 move from rear to front, and correspondingly, the damping fluid 630 flows from front to rear. The rear-flowing damping fluid 630 contacts the tapered surface 623a located on the pressure-bearing side PS and applies an acting force F1 to the piston element 620. The acting force F1 can be decomposed into a first component F11 parallel to the tapered surface 623a and a second component F12 perpendicular to the tapered surface 623a. The second component F12 causes the piston element 620 to deform radially inward, i.e., the piston element 620 will be compressed and thinned, and the overall shape of the piston element 620 will be deformed from the original state shown by the dashed line to the thinned state shown by the solid line. Figure 8 The single-side narrowest width of the damping passage 213 when the piston element 620 is not deformed is K, and the single-side narrowest width of the damping passage 213 after the piston element 620 is compressed and thinned is K1, K1>K, i.e., the cross-sectional area of the damping passage 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 compressed and thinned, its axial length will increase. In order to enable the piston element 620 to deform sufficiently, a certain axial gap can be reserved between the limiting portion 643 and the first end surface 621 during assembly, which provides sufficient axial deformation space for the piston element 620. In other alternative embodiments of the present embodiment, the single-side axial cross-sectional shape of the radial pressure-bearing surface RS can also be set to an arc shape or a broken line shape connected by multiple line segments, or other reasonable shapes, as long as the outer diameter of the radial pressure-bearing surface RS gradually increases from front to rear.

[0098] In combination with Figure 9 , when the release function is activated by the pushing actuator, the tubular telescopic component 300 moves from front to rear under the action of the load pressure Fb1, and the piston rod 610 and the piston element 620 also move from front to rear. Correspondingly, the damping fluid 630 flows from rear to front, and the front-flowing damping fluid 630 contacts the axial pressure-bearing surface AS located on the pressure-bearing side PS and applies an acting force F2 to the piston element 620. The acting force F2 causes the piston element 620 to deform radially outward, i.e., the piston element 620 will be compressed and thickened, and the overall shape of the piston element 620 will be deformed from the original state shown by the dashed line to the thickened state shown by the solid line. Figure 9The original state shown by the dotted line is changed into the thickened state shown by the solid line. The single-side narrowest width of the damping passage 213 when the piston element 620 is not deformed is K, and the single-side narrowest width of the damping passage 213 after the piston element 620 is thickened under pressure is K2, K2

[0099] In order to keep the minimum cross-sectional area of the damping passage 213 basically stable during the radial deformation of the piston element 620, in the embodiment, the outer circumferential surface 623 of the piston element 620 further has an equal-diameter surface 623b, which is located between the first end surface 621 and the tapered surface 623a and extends in the axial direction for a certain length. Specifically, the piston element 620 is provided with a cylindrical section with an equal diameter at the rear end thereof, and the outer circumferential surface of the cylindrical section forms the equal-diameter surface 623b. The equal-diameter surface 623b keeps the maximum outer diameter of the piston element 620 basically stable during the radial deformation when the piston element 620 is thickened under axial pressure or is thinned under radial pressure, so as to keep the minimum cross-sectional area of the damping passage 213 basically stable during the radial deformation of the piston element 620, and further to keep the damping action on the tubular telescopic component 300 stable during the release or actuation of the tubular telescopic component 300, thereby avoiding the situation that the movement of the tubular telescopic component 300 is fast or slow due to the large or small damping action, 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 surface 621, the straight line L2 represents the axial position of the second end surface 622, and the straight line L3 represents the boundary between the conical surface 623a and the constant-diameter surface 623b. The part of the outer circumferential surface of the piston element 620 between the straight line L2 and the straight line L3 constitutes a radial pressure-bearing surface RS gradually deviated toward the axial center of the piston element 620 from back to front, and the part of the outer circumferential surface of the piston element 620 between the straight line L3 and the straight line L1 constitutes the constant-diameter surface 623b. Correspondingly, the cross-sectional area of the damping passage 213 between the straight line L2 and the straight line L3 gradually increases from back to front, and the cross-sectional area of the damping passage 213 between the straight line L3 and the straight line L1 is basically consistent from front to back. Of course, as an alternative to the present embodiment, the piston element 620 can also cancel the setting of the constant-diameter surface 623b, that is, the outer circumferential surface 623 of the piston element 620 is entirely provided as a conical surface 623a or a structure similar to the conical surface.

[0100] In combination with Figure 10 , Figure 11 , Figure 12 , in the present embodiment, the clutch 400 is arranged on the outer periphery of the optical axis segment 230 and axially arranged along the front-rear direction. In order to improve the working safety, the coupling structure 800 capable of axial coupling is further arranged between the clutch 400 and the lead screw 200, and in addition, the clutch 400 in the present embodiment also has a self-locking function for the lead screw 200. In order to make the lead screw 200 meet the structural requirements, the optical axis segment 230 of the lead screw 200 includes a first shaft segment 231 and a second shaft segment 232, the second shaft segment 232 is located behind the first shaft segment 231, the rear end of the first shaft segment 231 is fixedly connected with the front end of the second shaft segment 232, and the front end of the second shaft segment 232 is inserted into the threaded segment 220 to close the rear end of the fluid chamber 210.

[0101] In the embodiment, the clutch 400 is axially positioned in the casing 710 by the front locating seat 730 and the rear locating seat 740 which are axially spaced apart, and the clutch 400 comprises a sun gear 401, a planet gear 402, a planet carrier 403, an inner ring 404, a brake seat 405, a torque input 406, a torque output 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 segment 231, and the sun gear 401 is in clearance fit with the first shaft segment 231 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, and the worm gear 122 and the sun gear 401 are kept in mutual positioning 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 planet gear 402 is rotatably arranged on the planet carrier 403 and axially located between the front carrier body 4031 and the rear carrier body 4032 of the planet carrier 403. The planet gear 402 is circumferentially spaced apart, and each planet gear 402 is in mesh with the sun gear 401. The inner ring 404 is rotatably sleeved on the outer periphery of all the planet gears 402, and each planet gear 402 is in mesh with the inner ring 404. The brake seat 405 is rotatably arranged in the casing 710, and the front end of the inner ring 404 and the rear end of the brake seat 405 are connected by the spline fit structure so that the states of the two can be kept synchronous. The torsion spring 410 is sleeved on the outer periphery of the brake seat 405, and the torsion spring 410 has a first torsion leg 4101 and a second torsion leg. The first torsion leg 4101 is connected to the release member 500, and the second torsion leg is inserted into a hole in the casing 710 to be positioned and arranged. In the normal state, the torsion spring 410 tightly holds the brake seat 405 so that the brake seat 405 and the inner ring 404 are kept fixed in the normal state. When the operated release member 500 applies force to the first torsion leg 4101 to make the torsion spring 410 release the brake seat 405, the brake seat 405 and the inner ring 404 are in a rotatable state, so that the screw rod 200 can be released, thereby activating the release function of the linear actuator 10. The torque input 406 is in clearance fit with the outside of the first shaft segment 231, and the torque input 406 is located in front of the planet carrier 403 and is axially positioned on the inner periphery of the brake seat 405. The rear end of the torque input 406 is in transmission connection with the front carrier body 4031 of the planet carrier 403 by the spline fit structure, and the front end of the torque input 406 is provided with a plurality of input keys 4061 which are circumferentially spaced apart. Figure 16 , and the front end of the torque input 406 is provided with a plurality of input keys 4061 which are circumferentially spaced apart. Figure 17The torque output member 407 is sleeved on the outer periphery of the first shaft segment 231 and / or the second shaft segment 232 by a clearance fit, the torque output member 407 is provided with a plurality of output keys 4071 extending rearward and matched with the input keys 4061, and the outer peripheral surface 623 of the torque output member 407 is provided with a self-locking angle 4072, the outer side surface of the self-locking angle 4072 away from the axis of the torque output member 407 is substantially 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. In combination with Figure 18 The retaining ring 408 is axially positioned on the outer periphery of the front end of the torque input member 406 and the rear end of the torque output member 407, and is located on the inner periphery 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 matched with the input keys 4061, and the retaining ring 408 is provided with an arc-shaped groove 4082 for installing the brake block 409 in the circumferential direction. The brake block 409 is arc-shaped and is provided with a plurality of blocks spaced apart in the circumferential direction, the number of the self-locking angle 4072, the brake block 409 and the arc-shaped groove 4082 is consistent and one-to-one corresponding, the brake block 409 is axially positioned at the arc-shaped groove 4082 by the limiting ring 411, the brake block 409 can move radially relative to the retaining ring 408 under the abutting action of the self-locking angle 4072, the brake block 409 abuts against the brake seat 405 to achieve friction braking under the outward abutting of the self-locking angle 4072, and the brake block 409 is separated from the brake seat 405 to release the friction braking under the release of the self-locking angle 4072. In combination with Figure 15 The input keys 4061, the output keys 4071 and the retaining keys 4081 are distributed in sequence in the circumferential direction, the key groove width between the adjacent two input keys 4061 is slightly larger than the sum of the key widths of the retaining keys 4081 and the output keys 4071, so that there is 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] In combination with Figure 13 , Figure 14In the 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 segment 232 in front of the torque output 407 through a clearance fit. The driven coupling 820 is arranged around the outer periphery of the second shaft segment 232 through a tight fit, a non-circular shaft hole fit or a spline fit. The driving coupling 810 and the driven coupling 820 adopt a tooth-shaped fit structure that can be axially clutched. The driving coupling 810 and the torque output 407 can be integrally formed, can be fixed together after being separately formed, or can be transmission-connected through a spline fit structure after being separately formed. In addition, in order to keep the driving coupling 810 and the driven coupling 820 in a stable coupling state in a normal state, the rear end of the first shaft segment 231 is sleeved with a first spring 240. The rear end of the first shaft segment 231 is fixed with a positioning piece 250 located behind the first spring 240. The rear end of the first spring 240 is positioned. The front end of the first spring 240 abuts against the positioning piece 250. The first spring 240 is in a compressed state and biases the lead screw 200 rearward by abutting against the positioning piece 250. The lead screw 200 biased rearward keeps the driven coupling 820 and the driving coupling 810 in engagement.

[0103] In combination Figure 20 In the embodiment, the release component 500 includes a cable 510, a release connecting rod 520, a sliding plate 530 and a second spring 540. The outer side of the casing 710 is provided with two spaced-apart limiting plates 711. The distribution direction of the two limiting plates 711 is perpendicular to the front-rear direction. The limiting plate 711 is provided with a limiting groove 712 extending in the front-rear direction for a certain length. The two ends of the sliding plate 530 are inserted into the limiting grooves 712. The sliding plate 530 is slidably arranged relative to the casing 710 in a direction perpendicular to the front-rear direction, such as the left-right direction. The sliding plate 530 is provided with a limiting hole 531 for inserting the first torsion leg 4101 of the torsion spring 410. The sliding plate 530 is also provided with an obliquely extending long hole 532 relative to the front-rear direction. The release connecting rod 520 is movably arranged on the outer side of the casing 710. The rear end of the release connecting rod 520 is fixed with a pin column 550 inserted into the long hole 532. The cable 510 is movably arranged on the outer side of the casing 710. The rear end of the cable 510 is connected to the front end of the release connecting rod 520. The front end of the cable 510 can be operated by a user. The second spring 540 is sleeved outside the rear end of the cable 510. The front end of the second spring 540 is positioned. The rear end of the second spring 540 abuts against the release connecting rod 520. The second spring 540 is in a compressed state and biases the release connecting rod 520 and the cable 510 rearward. Figure 20 In a 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 this time, the pin column 550 is located at the rear end of the long hole 532. Figure 21When the cable 510 is pulled forward, the pulled cable 510 drives the release link 520 to move forward against the bias of the second spring 540, the forward moving release link 520 drives the sliding plate 530 to slide relative to the casing 710 through the cooperation of the pin post 550 and the long hole 532, the sliding sliding plate 530 drives the first torsion leg 4101 of the torsion spring 410 to deflect in the loosening direction, the loosened torsion spring 410 loosens the brake seat 405, so that the brake seat 405 is in a rotatable state.

[0104] In the normal state, the lead screw 200 is in a state of coupling the driven coupling 820 and the driving coupling 810 under the bias of the first spring 240, the release component 500 is in a state of loosening the first torsion leg 4101 under the bias of the second spring 540, and the torsion spring 410 is in a state of holding the brake seat 405 in the normal state, that is, the brake seat 405 is in a fixed state in the normal state, and correspondingly, the inner tooth ring 404 is also in a fixed state.

[0105] When the pushing actuator actuates the load to 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 406 to rotate along the direction of +ω shown through the planetary gear 402 and the planet carrier 403, the rotating torque input 406 drives the torque output 407 to rotate along the direction of +ω shown through the interference fit of the input key 4061 and the output key 4071, the initially rotating torque output 407 releases the self-locking angle 4072 from the brake block 409, the released brake block 409 moves close to the shaft center of the retaining ring 408 and is in the state of being radially close to the inside relative to the retaining ring 408, so as to release the friction brake between the brake block 409 and the brake seat 405, and then the torque input 406 drives the torque output 407, the retaining ring 408 and the brake block 409 to rotate, the rotating torque output 407 drives the lead screw 200 to rotate along the direction of +ω shown through the driving shaft 810 and the driven shaft 820, the rotating lead screw 200 drives the inner tube 310 to move forward through the nut 330, the moving forward inner tube 310 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, the damping fluid 630 in the fluid chamber 210 flows backward from the second chamber 212 to the first chamber 211 through the damping channel 213, the backward flowing damping fluid 630 acts on the radial pressure surface RS to make the piston element 620 thin under pressure, so as to increase the cross-sectional area of the damping channel 213, and further reduce the damping force of the damping fluid 630 on the tubular telescopic part 300, thereby ensuring the actuating efficiency. When the tubular telescopic part 300 pushes the load to the specified position, the actuating unit 110 stops working, at this time, the lead screw 200 drives the driven shaft 820, the driving shaft 810 and the torque output 407 to rotate along the direction of -ω shown under the action of the load pressure, the self-locking angle 4072 rotating synchronously with the torque output 407 pushes the brake block 409 outward away from the shaft center of the retaining ring 408, the brake block 409 is in the state of being radially close to the outside relative to the retaining ring 408, the outward brake block 409 interferes with the brake seat 405 to realize the friction brake, so as to prevent the lead screw 200 from continuing to rotate, thereby realizing the self-locking of the lead screw 200. In this embodiment, a brake ring corresponding to the brake block 409 can also be additionally arranged on the inner periphery of the brake seat 405, and the brake block 409 interferes with the brake ring to realize the friction brake.

[0106] When the pushing actuator actuates the load to make the load back off, the actuating unit 110 works and drives the sun gear 405 to rotate reversely through the cooperation of the worm 121 and the worm wheel 122, the sun gear 401 drives the torque input 406 to rotate along the direction shown by -ω through the planet wheel 402 and the planet carrier 403, the torque input 406 that rotates initially drives the retaining ring 408 to rotate through the interference fit of the input key 4061 and the retaining key 4081, the retaining ring 408 drives the brake block 409 to rotate by a certain angle to make the brake block 409 be released by the self-locking angle 4072 first, so as to release the frictional braking between the brake block 409 and the brake seat 405, then the torque input 406 drives the torque output 407, the retaining ring 408 and the brake block 409 to rotate together, the rotating torque output 407 drives the lead screw 200 to rotate along the direction shown by -ω through the driving shaft 810 and the driven shaft 820, the rotating lead screw 200 drives the inner tube 310 to move backward through the nut 330, the backward moving inner tube 310 drives the load to back off through the front joint 350. The self-locking action of the lead screw 200 in this process is the same as the foregoing description, which will not be described here.

[0107] When quick release is needed, the user exerts force on the pull cable 510 to make the pull cable 510 drive the release link 520 to move forward against the bias of the second spring 540, the forward moving release link 520 drives the sliding plate 530 to slide through the cooperation of the pin post 550 and the long hole 532, the sliding sliding plate 530 drives the first torsion leg 4101 of the torsion spring 410 to deflect towards the loosening direction through the limiting hole 531 to make the torsion spring 410 release the brake seat 405, the brake seat 405 released by the torsion spring 410 is in a rotatable state, accordingly, the inner gear ring 404 is also in a rotatable state. Under the action of load pressure, the lead screw 200 continuously rotates in the direction indicated by -ω, the rotating lead screw 200 drives the torque output 407 to rotate in the direction indicated by -ω through the driven coupling 820 and the driving coupling 810, the rotating torque output 407 drives the retainer ring 408, the brake block 409, the brake seat 405, the torque input 406, the planet carrier 403, the planet gear 402, and the inner gear ring 404 to rotate together, the sun gear 401 cannot rotate under the self-locking cooperation of the worm gear 122 and the worm wheel 121 or the self-locking action of the motor, the rotating inner gear ring 404 releases the rotating torque caused by the load pressure. The tubular telescopic component 300 quickly retracts under the action of load pressure, achieving the purpose of quick release without the need for motor actuation. The piston rod 610 and the piston element 620 move from front to back during the release process, the damping fluid 630 in the fluid chamber 210 flows from the first chamber 211 to the second chamber 212 forward through the damping channel 213, the forward flowing damping fluid 630 acts on the axial pressure surface AS to make the piston element 620 thicken under pressure, thereby reducing the cross-sectional area of the damping channel 213, and further 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, avoiding damage caused by the tubular telescopic component 300 releasing too quickly. When the tubular telescopic component 300 retracts to the predetermined position, the pull cable 510 is loosened, the second spring 540 that has deformed drives the release link 520 and the pull cable 510 to move forward, the sliding plate 530 resets to loosen the first torsion leg 4101, and the torsion spring 410 returns to the state of holding the brake seat 405, thereby making the brake seat 405 and the inner gear ring 404 return to the fixed state, and the brake block 409 and the brake seat 405 frictionally brake to stop the lead screw 200 from rotating.

[0108] In the process of the tubular telescopic component 300 actuating the load to make the load retract, when other objects are between the load and the front end of the outer tube 320 to block the retraction of the lead screw 200, the lead screw 200 moves axially forward relative to the clutch 400 against the bias of the first spring 240, the forward moving lead screw 200 drives the driven coupling 820 to move synchronously to make the driven coupling 820 disengage from the driving coupling 810, thereby blocking the clutch 400 from transmitting torque to the lead screw 200 through the coupling structure 800, that is, the tubular telescopic component 300 stops actuating when it encounters resistance.

[0109] It can be understood that the first shaft segment 231 and the second shaft segment 232 of the optical axis segment 230 can also be integrally formed, provided that the assembly requirements of the relevant components in the clutch 400 are met.

[0110] It can be understood that the clutch 400 of the present embodiment is designed according to a planetary gear transmission structure, wherein the release component 500 is specially configured to pull the torsion spring 410 to act, thereby achieving the disconnection of the power transmission between the planetary gear transmission mechanism and the lead screw 200. However, the present utility model is not limited to this design, and the clutch can also adopt other known structures to achieve the holding or cutting function of the power transmission between the actuating unit 110 and the lead screw 200. For example, the clutch mechanism realized by the cooperation of the clutch sleeve and the left connecting piece disclosed in CN214367368U can be referred to, in which case the release component activates the release operation by promoting the axial movement of the clutch sleeve; for another example, the clutch mechanism disclosed in CN118391414A, in which the release component also triggers the release function by guiding the axial displacement of the clutch sleeve.

[0111] It can be understood that the clutch 400 in the present embodiment can also cancel the settings of the retaining ring 408, the brake block 409, the limiting 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 lead screw 200 is realized by the cooperation of the worm wheel 122 and the worm 121, so that the tubular telescopic component 300 remains stable, avoiding the backward movement of the tubular telescopic component 300 under the action of the load.

[0112] Embodiment Two

[0113] In the present embodiment, the linear actuator is a pulling actuator, and the tubular telescopic component pulls the load towards the actuating unit, i.e., 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 under the action of the load pulling force, i.e., the tubular telescopic component is quickly moved forward under the action of the load pulling force after being released.

[0114] In combination Figure 22In the 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 columnar with a front end being thick and a rear end being thin, 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 a part of the outer circumferential surface of the piston element 620 is the tapered surface 623a gradually deviated from the axial center of the piston element 620 from the first end surface 621 to the second end surface 622, the tapered surface 623a constitutes the radial pressure bearing surface RS, and correspondingly, the cross-sectional area of the damping passage gradually increases from the front to the rear. In addition, the outer circumferential surface of the piston element 620 further includes the constant-diameter surface between the tapered surface and the first end surface 621. In the embodiment, the outer circumferential surface 623 of the piston element 620 can also be arranged in other shapes to gradually deviate the outer diameter of the radial pressure bearing surface RS from the axial center of the piston element 620 from the first end surface 621 to the second end surface 622, such as arranging the single-side cross-sectional shape of the radial pressure bearing surface RS in the axial direction in 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 the front to the rear; of course, the outer circumferential surface of the piston element 620 can also cancel the arrangement of the constant-diameter surface.

[0115] In combination Figure 22 When the actuator is pulled to actuate the load to move backward, the distance of the tubular telescopic component moving backward constitutes the working stroke generated by the linear movement of the tubular telescopic component in the first direction, i.e., the first direction in the embodiment is the backward direction, at this time, the piston rod 610 and the piston element 620 move backward with the tubular telescopic component, the damping fluid in the fluid chamber is extruded and flows forward from the first chamber 211 to the second chamber 212 through the damping passage 213, at the same time, the radial pressure bearing surface RS is located at the pressure bearing side PS, and the axial pressure bearing surface AS is located at the back pressure side BPS, the damping fluid flowing from the rear to the front applies pressure to the piston element 620 through the radial pressure bearing surface RS, and the piston element 620 deforms radially inward under pressure, i.e., the piston element 620 will be thin under pressure, and the overall shape of the piston element 620 is roughly changed from the original state shown by the dashed line to the thin state shown by the solid line. Figure 22 The cross-sectional area of the damping passage increases under the condition that the piston element 620 is thin under pressure, so that the damping force Fd3 of the damping fluid on the tubular telescopic component can be appropriately reduced.

[0116] In combination Figure 23When the release function is activated by pulling the actuator 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 action of the load tension Fb2 constitutes the release stroke generated by the linear movement of the tubular telescopic component in the second direction, i.e. the forward direction in this embodiment, at this time, the piston rod 610 and the piston element 620 move forward with the tubular telescopic component, the damping fluid in the fluid chamber is extruded and flows from the second chamber 212 to the first chamber 211 through the damping passage in the rear direction, at the same time, the axial pressure surface AS is located on the pressure side PS, and the radial pressure surface RS is located on the back pressure side BPS, the damping fluid flowing from the front to the rear applies pressure to the piston element 620 through the axial pressure surface AS, and the piston element 620 deforms radially outward under pressure, i.e. the piston element 620 will thicken under pressure, and the overall shape of the piston element 620 is roughly changed from the original state shown by the dashed line to the thickened state shown by the solid line. The cross-sectional area of the damping passage decreases when the piston element 620 thickens under pressure, and the damping force Fd4 that the damping fluid flowing in the reverse direction applies to the tubular telescopic component increases, so that the tubular telescopic component can be slowly released under the action of the load tension. Figure 23

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

[0118] The other structures of Embodiment Two are the same as those of Embodiment One, which will not be described here.

[0119] Embodiment Three

[0120] In this embodiment, the piston element 620 is roughly a front-rear equally thick cylinder, and its outer diameter is basically the same as the inner diameter of the fluid chamber 210. In order to smoothly form the damping passage 213, a hole extending from one end face to the other end face of the piston element 620 is provided on the piston element 620, and the internal space of the hole is used to form the damping passage 213.

[0121] In combination with Figure 24 ​In the push actuator, the hole on the piston element 620 is a roughly front-thick and rear-thin conical hole 625, the first end face 621 at the rear end of the piston element 620 constitutes an axial pressure bearing surface AS, the hole wall of the conical hole 625 constitutes a radial pressure bearing surface RS, and the conical hole 625 constitutes the damping passage 213. When the push actuator drives the load to move forward, the damping fluid in the second chamber flows backward toward the first chamber through the damping passage 213, at this time, the radial pressure bearing surface RS is located at the pressure side PS, and the axial pressure bearing surface AS is located at the back pressure side BPS. The damping fluid flowing from front to back contacts the radial pressure bearing surface RS, which makes the radial pressure bearing surface RS expand outward under force, the inner diameter of the conical hole 625 increases, and correspondingly, the cross-sectional area of the damping passage 213 increases, so that the damping force of the damping fluid on the tubular telescopic component can be appropriately reduced. When the push actuator activates the release function and 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 passage 213, at this time, the axial pressure bearing surface AS is located at the pressure side PS, and the radial pressure bearing surface RS is located at the back pressure side BPS. The damping fluid flowing from back to front contacts the axial pressure bearing surface AS, which makes the piston element 620 deform under pressure. The piston element 620 deformed under pressure makes the inner diameter of the rear end of the conical hole 625 decrease, and correspondingly, the cross-sectional area of the damping passage 213 decreases. The damping fluid flowing in the reverse direction increases the release damping force on the tubular telescopic component, so that the tubular telescopic component can be slowly released under the action of the load pressure.

[0122] In combination Figure 25In the pull actuator, the hole on the piston element 620 is a tapered hole 625 with a smaller diameter at the front end and a larger diameter at the back end. The first end face 621 of the piston element 620 at the front end constitutes an axial pressure receiving surface AS, and the hole wall of the tapered hole 625 constitutes a radial pressure receiving surface RS. The tapered hole 625 constitutes the damping passage 213. When the pull actuator actuates the load to move the load rearward, the damping fluid in the first chamber flows forward toward the second chamber through the damping passage 213. At this time, the radial pressure receiving surface RS is located at the pressure receiving side PS, and the axial pressure receiving surface AS is located at the back pressure side BPS. The damping fluid flowing rearward to forward contacts the radial pressure receiving surface RS, which is forced to expand outward, and the inner diameter of the tapered hole 625 increases, and the cross-sectional area of the damping passage 213 increases, so that the damping force of the damping fluid on the tubular telescopic member can be appropriately reduced. When the pull actuator activates the release function and the tubular telescopic member moves forward under the action of the load tension, the damping fluid in the second chamber flows rearward toward the first chamber through the damping passage 213. At this time, the axial pressure receiving surface AS is located at the pressure receiving side PS, and the radial pressure receiving surface RS is located at the back pressure side BPS. The damping fluid flowing rearward to forward contacts the axial pressure receiving surface AS, which is forced to deform under pressure, and the inner diameter of the tapered hole 625 at the front end decreases, and the cross-sectional area of the damping passage 213 decreases. The damping fluid 630 flowing in the reverse direction increases the release damping force on the tubular telescopic member 300, so that the tubular telescopic member can be slowly released under the action of the load pressure.

[0123] It can be understood 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 provided in other shapes that meet the damping requirements.

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

[0125] It can be understood that the hole on the piston element 620 can be provided in several intervals.

[0126] The other structures of the third embodiment are referred to the first embodiment or the second embodiment.

[0127] Embodiment Four

[0128] In this embodiment, the inner circumferential surface of the fluid chamber is provided with an axial groove extending from the inner circumferential surface of the fluid chamber away from the axis of the fluid chamber to a certain depth, and the groove wall of the groove cooperates with the outer circumferential surface of the piston element to form the damping passage. In order to adaptively change the cross-sectional area of the damping passage, the outer circumferential surface of the piston element can be provided with a corresponding tapered surface according to the type of the linear actuator, and the maximum outer diameter of the piston element can be substantially the same as the inner diameter of the fluid chamber.

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

[0130] In the pull actuator, the cross-sectional area of the damping passage formed by the groove wall of the groove and the outer circumferential surface of the piston element is gradually increased from front to back.

[0131] It can be understood that the groove in embodiment four can be combined with the hole on the piston element in embodiment three to form a damping passage.

[0132] It can be understood that the grooves on the inner circumferential surface of the fluid chamber in the embodiment can be circumferentially spaced several.

[0133] Other structures of embodiment four refer to embodiment one or embodiment two.

[0134] In addition to the preferred embodiments described above, the utility model also has other implementation manners, and those skilled in the art can make various changes and deformations according to the utility model, as long as they do not deviate from the spirit of the utility model, and all should belong to the range defined in the claims of the utility model.

Claims

1. A safety-released linear actuator comprising: an actuating unit for providing an actuating torque; a screw rod driven to rotate by the actuating torque; a tubular telescopic member sleeved on the screw rod and driven to linearly extend and retract by the rotational movement of the screw rod; a clutch for maintaining or interrupting the power transmission between the actuating unit and the screw rod; a releasable member operable to drive the clutch to interrupt the power transmission between the actuating unit and the screw rod and activate a release function of the linear actuator; characterized in that the linear actuator further comprises: a fluid chamber axially extending inside the screw rod and filled with a damping fluid, 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 and connected to the tubular telescopic member, the portion of the piston rod inserted into the fluid chamber being configured as a piston element, the fluid chamber being 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 provided inside the fluid chamber and allowing the damping fluid to flow through the piston element to communicate the first chamber and the second chamber; after the linear actuator activates the release function, the damping fluid is limited to flow through the damping passage to provide a damping force against the load force.

2. The safety-released linear actuator of claim 1, wherein the linear actuator is configured as a push actuator, the tubular telescopic member pushes the load away from the actuating unit, after the linear actuator activates the release function, the tubular telescopic member is released to move towards the actuating unit under the load pushing force, the damping fluid in the first chamber is limited to flow through the damping passage into the second chamber to provide a damping force against the load pushing force.

3. The safety-released linear actuator of claim 1, wherein the linear actuator is configured as a pull actuator, the tubular telescopic member pulls the load towards the actuating unit, after the linear actuator activates the release function, the tubular telescopic member is released to move away from the actuating unit under the load pulling force, the damping fluid in the second chamber is limited to flow through the damping passage into the first chamber to provide a damping force against the load pulling force.

4. The safety-released linear actuator of claim 1, wherein defining a first direction linear movement of the tubular telescopic member as a working stroke and a second direction linear movement of the tubular telescopic member opposite to the first direction as a release stroke, at least a portion of the damping passage has a variable cross-sectional area, such that the portion of the damping passage provides a larger cross-sectional area in the working stroke than in the release stroke.

5. The safety-released linear actuator of claim 4, wherein the damping passage is formed by at least partially leaving a gap between a portion of the inner circumferential surface of the fluid chamber corresponding to the piston element and the outer circumferential surface of the piston element, the piston element reversibly deforms radially under the pressure of the damping fluid to change the cross-sectional area of the damping passage.

6. The safety-released linear actuator of claim 5, wherein, the damping passage is formed circumferentially continuously between the portion of the inner circumferential surface of the fluid chamber corresponding to the piston element and the outer circumferential surface of the piston element.

7. The safety-released linear actuator of claim 5, wherein the safety release mechanism comprises a spring. the piston element has a radial pressure receiving surface and an axial pressure receiving surface; in the working stroke of the tubular telescopic member, the radial pressure receiving surface is located on the pressure receiving side of the piston element and receives the radial pressure of the damping fluid to make the piston element deform radially inwardly, the axial pressure receiving surface is located on the pressure receiving side of the piston element. During the releasing stroke of the tubular telescopic component, the axial pressure surface is located at the pressure side of the piston element, and the piston element is deformed radially outwardly under the axial pressure of the damping fluid, and the radial pressure surface is located at the back pressure side of the piston element.

8. The safety-released linear actuator of claim 7, wherein the safety release mechanism comprises a spring. The piston element comprises an axially spaced first end face and a second end face, and an outer circumferential 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 consistent with the first direction; At least part of the first end face of the piston element constitutes the axial pressure surface; At least part of the outer circumferential surface of the piston element constitutes the radial pressure surface, and the part of the outer circumferential surface gradually deviates from the axial center of the piston element along the first direction, and the cross-sectional area of the damping channel corresponding to the part of the radial pressure surface unidirectionally increases along the first direction.

9. The safety-released linear actuator of claim 7, wherein, Part of the outer circumferential surface of the piston element constitutes an equidiameter surface, and the equidiameter surface is located between the axial pressure surface and the radial pressure surface.

10. The safety-released linear actuator of claim 5, wherein, The linear actuator further comprises a fixing element, the fixing element comprises a connecting part, a limiting part and a supporting part located therebetween, the connecting part is connected to the insertion end of the piston rod through the piston element, the piston element is axially clamped and limited by the insertion end of the piston rod and the limiting part, and the supporting part axially penetrates the piston element for centering and supporting thereof.

11. The safety-released linear actuator of claim 10, wherein, The connection between the connecting part and the insertion end of the piston rod is provided as a threaded connection; and / or, the connection between the limiting part and the supporting part is provided as a threaded connection.

12. The safety-released linear actuator of claim 1, wherein, The first end of the fluid chamber is a closed end, and the second end provides an opening for the insertion of the piston rod, and a sealing element is arranged at the opening for providing dynamic sealing between the second end and the piston rod.

13. The safety-released linear actuator of claim 1, wherein The damping channel comprises a hole axially penetrating the piston element; and / or, the damping channel comprises a groove axially extending on the inner circumferential surface of the fluid chamber.

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