Secure release linear actuator

Abstract

The utility model discloses a linear actuator capable of being released safely. The linear actuator comprises an actuating unit and a lead screw. The tubular telescopic component is sleeved outside the lead screw and is driven by the rotary motion of the lead screw to do linear telescopic motion; a clutch for maintaining or cutting off power transmission between the actuating unit and the screw rod; the operable release component drives the clutch to cut off power transmission between the actuating unit and the screw rod so as to activate the release function of the linear actuator; the brake unit comprises at least one brake arm which is constructed into a lever structure in the linear telescopic movement direction of the tubular telescopic component, and the brake arm comprises a clamping arm and a driving arm which are located on the two sides of the fulcrum of the brake arm; after the linear actuator activates the releasing function, the driving arm responds to the releasing action of the releasing component to drive the clamping arm to be in friction joint with the outer surface of the tubular telescopic component, and the clamping arm is used for controlling the releasing speed of the tubular telescopic component under the action of load force. The linear actuator provided by the utility model can realize slow release.

Description

Technical Field

[0001] This utility model relates to the field of linear actuator technology, and more particularly to a linear actuator with safe release. Background Technology

[0002] Linear actuators, also known as electric linear actuators, are widely used in furniture, medical equipment, solar power generation, and other fields. Their main structure includes an actuation unit that provides 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 threaded to the outside of the lead screw and an inner tube fixedly fitted on the outside of the nut. The working principle is: the actuation unit drives the lead screw to rotate, and the rotation of the lead screw will drive the nut to move along the axial direction of the lead screw, so that the nut drives the inner tube to move axially, thereby realizing the linear telescopic movement of the tubular telescopic component.

[0003] Considering the application environment of linear actuators, when encountering motor failure, power outages, or other situations requiring power interruption, a clutch and an operable release mechanism are typically added to release and retract the tubular telescopic component. The clutch maintains or disconnects the power transmission between the actuator unit and the lead screw. Operating the release mechanism drives the clutch to disconnect the power transmission between the actuator unit and the lead screw, activating the release function. This allows the lead screw to rotate under load, driving the tubular telescopic component to rapidly displace and release. The greater the load, the greater the release speed of the tubular telescopic component. When used as a push actuator on an electric bed, rapid release above a certain weight may cause injury to the user. When used as a pull actuator in lifting applications, rapid release under heavy loads results in a very fast descent speed, which may cause damage to the load, objects below, or people. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a safe release linear actuator that can control the release speed of the tubular telescopic component under load force so that it can achieve slow release.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A safe-release linear actuator includes:

[0007] An actuation unit that provides actuating torque;

[0008] A lead screw that is driven to rotate by an actuating torque;

[0009] A tubular telescopic component is fitted outside the lead screw and is driven by the rotational motion of the lead screw to perform linear telescopic motion;

[0010] A clutch is used to maintain or disconnect the power transmission between the actuator and the lead screw.

[0011] An operable release component that drives the clutch to cut off the power transmission between the actuator unit and the lead screw, thereby activating the release function of the linear actuator;

[0012] The linear actuator further includes:

[0013] A braking unit includes at least one brake arm configured as a lever along the linear telescopic movement direction of a tubular telescopic member, the brake arm including a clamping arm and a driving arm located on both sides of its fulcrum.

[0014] After the linear actuator activates the release function, the drive arm responds to the release action of the release component and drives the clamping arm to frictionally engage with the outer surface of the tubular telescopic component, thereby controlling the release speed of the tubular telescopic component under load.

[0015] When the linear actuator in this invention is activated and its release function is activated, the lead screw will rotate freely. The release action of the release component drives the drive arm to rotate around the fulcrum, which can drive the clamping arm to rotate towards the tubular telescopic component and frictionally engage with the outer surface of the rapidly releasing tubular telescopic component. This generates a frictional damping force between the clamping arm and the tubular telescopic component that is opposite to the direction of movement of the tubular telescopic component, thereby reducing the release speed of the tubular telescopic component and allowing it to release slowly to avoid damage to the load.

[0016] In the aforementioned safe-release linear actuator, the linear actuator is configured to push the load away from the actuation unit. After the linear actuator activates the release function, the tubular telescopic component is released towards the actuation unit under the load thrust. The clamping arm frictionally engages with the outer surface of the tubular telescopic component, providing a frictional damping force to counteract the load thrust.

[0017] In the aforementioned safe-release linear actuator, the linear actuator is configured as a pull actuator, in which the tubular telescopic component pulls the load toward the actuation unit. After the linear actuator activates the release function, the tubular telescopic component is released away from the actuation unit by the load tension. The clamping arm frictionally engages with the outer surface of the tubular telescopic component, providing frictional damping force to counteract the load tension.

[0018] In the aforementioned linear actuator for safe release, the linear actuator includes an outer tube sleeved outside the tubular telescopic component. The tubular telescopic component performs linear telescopic movement relative to the outer tube, and the brake arm is pivotally connected to the outer side of the outer tube to form a lever structure. This design, by placing the brake arm outside the outer tube, provides sufficient operating space for the assembly of the brake arm, thereby facilitating the assembly and disassembly of the brake arm.

[0019] In the aforementioned linear actuator with safe release, the braking unit further includes a transmission guide component that reciprocates along the axial direction of the outer tube. The release component is axially pulled to perform the release action. The transmission guide component converts the axial pulling force of the release component into a radial driving force on the drive arm, thereby driving the drive arm radially away from the outer surface of the outer tube. Since the existing release component performs the release action under axial pulling, by setting a transmission guide component to convert the axial pulling force of the release component into a radial driving force on the drive arm to drive the drive arm radially away from the outer surface of the outer tube, the pulling direction of the existing release component can be maintained without changing it, thus reducing the degree of product modification and consequently reducing product modification costs.

[0020] In the aforementioned linear actuator for safe release, one of the transmission guide component and the drive arm is provided with a guide groove, and the other with a guide slider. The guide slider and the guide groove move axially relative to each other as the transmission guide component slides. The guide groove is constructed as a wedge-shaped groove and / or the guide slider is constructed as a wedge-shaped block. This design facilitates the insertion and engagement of the guide slider and the guide groove, and as the release stroke of the release component increases, the rotation angle of the brake arm also gradually increases. This ensures that the transmission guide component drives the drive arm further away from the outer surface of the outer tube, allowing the clamping arm to frictionally engage with the outer surface of the tubular telescopic component, or, after the clamping arm frictionally engages with the outer surface of the tubular telescopic component, the continued pushing of the drive arm increases the clamping force of the clamping arm on the tubular telescopic component, thereby improving the frictional damping force.

[0021] In the aforementioned linear actuator with safe release, the transmission guide component is constructed as a sleeve structure corresponding to the shape of the outer side of the outer tube. The transmission guide component is fitted onto the outer tube and guided axially by the outer tube. This design not only improves the assembly reliability of the transmission guide component and the outer tube, preventing the transmission guide component from falling off, but also simplifies the assembly and disassembly of the transmission guide component.

[0022] In the aforementioned linear actuator with safe release, the release component includes a cable and a sleeve connecting the cable. The sleeve is fitted onto an outer tube and guided axially by the outer tube. The axial sliding of the sleeve comes from the traction of the cable. The transmission guide component is axially abutted against the sleeve or forms an integral structure with the sleeve. With this design, pulling the cable will pull the sleeve to slide, thereby causing the sleeve to drive the transmission guide component to slide, resulting in a simple structure.

[0023] In the aforementioned linear actuator for safe release, the linear movement of the tubular telescopic component in the first direction is defined as the working stroke, and the linear movement of the tubular telescopic component under load in the second direction opposite to the first direction is defined as the release stroke. The clamping arm has a clamping surface facing the outer surface of the tubular telescopic component. The clamping surface gradually deviates from the outer surface of the tubular telescopic component along the first direction, and a gap with a radially increasing distance is formed between the clamping surface and the outer surface of the tubular telescopic component along the first direction. After the linear actuator activates the release function, the clamping surface gradually approaches and contacts the outer surface of the tubular telescopic component as the rotation angle of the brake arm increases.

[0024] In the aforementioned linear actuator for safe release, the contact area between the clamping surface and the outer surface of the tubular telescopic component increases with the increase of the rotation angle of the brake arm, and the rotation angle of the brake arm increases with the increase of the release stroke of the release component. This design allows control of the contact area between the clamping surface and the outer surface of the tubular telescopic component by controlling the release stroke of the release component. A larger contact area results in a better deceleration effect on the tubular telescopic component, thus allowing for adjustment of the release speed of the tubular telescopic component as needed.

[0025] In the aforementioned linear actuator with safe release, the length of the drive arm is greater than the length of the clamping arm. This design allows the brake arm to form a force-saving lever structure, reducing the radial outward thrust exerted by the transmission guide component on the drive arm while keeping the clamping force on the tubular telescopic component constant. This reduces the stress on the drive arm and prevents it from deforming or breaking due to excessive stress.

[0026] In the aforementioned linear actuator for safe release, the braking unit includes two braking arms configured as a cross lever structure along the linear telescopic movement direction of the tubular telescopic component. The two braking arms are distributed on opposite sides of the tubular telescopic component. This design increases the frictional contact area between the braking unit and the tubular telescopic component, thereby improving the frictional damping force on the tubular telescopic component and thus enhancing the deceleration effect, enabling the tubular telescopic component to release at a lower speed.

[0027] In the aforementioned linear actuator for safe release, the braking unit also includes an elastic component. This elastic component connects two braking arms, keeping the two clamping arms in a force-free state that keeps them away from each other. This design ensures that when the release function is not activated—that is, when the tubular telescopic component undergoes linear telescopic movement by rotating the lead screw driven by the actuation unit—the elastic component keeps the two clamping arms away from each other, preventing contact between the clamping arms and the outer surface of the tubular telescopic component. This avoids the braking unit applying frictional damping force to the telescopic movement of the tubular telescopic component, reducing the output power consumption of the actuation unit.

[0028] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and accompanying drawings. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings:

[0030] Figure 1 This is an exploded view of the linear actuator in Embodiment 1 of this utility model;

[0031] Figure 2 This is a schematic diagram of the brake arm in Embodiment 1 of this utility model;

[0032] Figure 3 This is a schematic diagram of the transmission guide component in Embodiment 1 of this utility model;

[0033] Figure 4 This is a schematic diagram of the linear actuator in Embodiment 1 of this utility model. Figure 1 ;

[0034] Figure 5 for Figure 4 A magnified view of part A in the diagram;

[0035] Figure 6 This is a schematic diagram of the linear actuator in Embodiment 1 of this utility model. Figure 2 ;

[0036] Figure 7 for Figure 6 A magnified view of part B in the diagram;

[0037] Figure 8 This is a cross-sectional view of the linear actuator in Embodiment 1 of this utility model when the release function is not activated;

[0038] Figure 9 for Figure 8 A magnified view of part of C;

[0039] Figure 10 for Figure 8 A magnified view of part of D;

[0040] Figure 11 This is a cross-sectional view of the linear actuator in Embodiment 1 of this utility model when its release function is activated;

[0041] Figure 12 for Figure 11 A magnified view of part of E in the diagram;

[0042] Figure 13 for Figure 11 A magnified view of part of F;

[0043] Figure label:

[0044] 001, Gap;

[0045] 100. Actuation unit; 200. Lead screw; 300. Tubular telescopic component; 310. Inner tube; 320. Drive nut; 400. Clutch; 410. Planetary gear set; 411. Sun gear; 412. Planet gears; 413. Planet carrier; 414. Ring gear; 420. Drive sleeve; 430. Brake sleeve; 440. Brake torsion spring; 441. First pin; 500. Release component; 510. Cable; 511. Drive pin; 512. Return spring; 520, Release plate; 521, Guide groove; 530, Sliding sleeve; 600, Braking unit; 610, Braking arm; 611, Drive arm; 6110, Guide groove; 612, Clamping arm; 6120, Clamping surface; 613, Mounting hole; 620, Transmission guide component; 621, Guide slider; 630, Elastic component; 700, Outer tube; 710, Fixed shaft; 800, First housing; 810, Mounting plate; 811, Limiting groove; 820, Limiting pin. Detailed Implementation

[0046] This utility model provides a safe-release linear actuator, comprising:

[0047] An actuation unit that provides actuating torque;

[0048] A lead screw that is driven to rotate by an actuating torque;

[0049] A tubular telescopic component is fitted outside the lead screw and is driven by the rotational motion of the lead screw to perform linear telescopic motion;

[0050] A clutch is used to maintain or disconnect the power transmission between the actuator and the lead screw.

[0051] An operable release component that drives the clutch to cut off the power transmission between the actuator unit and the lead screw, thereby activating the release function of the linear actuator;

[0052] The linear actuator further includes:

[0053] A braking unit includes at least one brake arm configured as a lever along the linear telescopic movement direction of a tubular telescopic member, the brake arm including a clamping arm and a driving arm located on both sides of its fulcrum.

[0054] After the linear actuator activates the release function, the drive arm responds to the release action of the release component and drives the clamping arm to frictionally engage with the outer surface of the tubular telescopic component, thereby controlling the release speed of the tubular telescopic component under load.

[0055] When the linear actuator in this invention is activated and its release function is activated, the lead screw will rotate freely. The release action of the release component drives the drive arm to rotate around the fulcrum, which can drive the clamping arm to rotate towards the tubular telescopic component and frictionally engage with the outer surface of the rapidly releasing tubular telescopic component. This generates a frictional damping force between the clamping arm and the tubular telescopic component that is opposite to the direction of movement of the tubular telescopic component, thereby reducing the release speed of the tubular telescopic component and allowing it to release slowly to avoid damage to the load.

[0056] The technical solutions of the embodiments of this utility model will be explained and described below with reference to the accompanying drawings. However, the following embodiments are only preferred embodiments of this utility model and not all of them. Based on the embodiments in the implementation, other embodiments obtained by those skilled in the art without creative effort are all within the protection scope of this utility model. In addition, it should be understood that the terms "upper," "lower," "left," "right," "longitudinal," "lateral," "inner," "outer," "vertical," "horizontal," "top," and "bottom," etc., indicating orientation or positional relationship, are only based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They are not intended to indicate or imply that the device / component must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0057] Example 1

[0058] like Figures 1 to 13 As shown, the linear actuator for safe release in this embodiment includes an actuation unit 100, a lead screw 200, a tubular telescopic component 300, a clutch 400, and an operable release component 500. The actuation unit 100 is a motor that provides actuation torque. The tubular telescopic component 300 includes an inner tube 310 and a transmission nut 320. The inner tube 310 is fitted onto the outside of the lead screw 200. The transmission nut 320 is threadedly connected to the outer end of the lead screw 200 near the actuation unit 100. The transmission nut 320 is circumferentially fixed and axially fixed relative to the inner tube 310. The clutch 400 is used to maintain or disconnect the connection between the actuation unit 100 and the lead screw 200. The power transmission and release component 500 is used to drive the clutch 400 to cut off the power transmission between the actuation unit 100 and the lead screw 200, thereby activating the release function of the linear actuator. When the linear actuator is not activated, the clutch 400 maintains the power transmission between the actuation unit 100 and the lead screw 200. At this time, the actuation torque provided by the motor can be transmitted to the lead screw 200 through the clutch 400, thereby driving the lead screw 200 to rotate. The rotation of the lead screw 200 drives the transmission nut 320 to drive the inner tube 310 to make linear displacement along the axial direction of the lead screw 200, thereby realizing the linear telescopic movement of the driven tubular telescopic component 300.

[0059] Specifically, such as Figure 9 As shown, the clutch 400 in this embodiment includes a planetary gear set 410, a transmission sleeve 420, a brake sleeve 430, and a brake torsion spring 440. The planetary gear set 410 includes a sun gear 411, planet gears 412, a planet carrier 413, and a ring gear 414. The planet gears 412 are rotatably mounted on the planet carrier 413. Multiple planet gears 412 surround the outside of the sun gear 411 and mesh with the sun gear 411. The ring gear 414 surrounds the outside of the multiple planet gears 412 and meshes with the planet gears 412. The transmission sleeve 420 and the ring gear 414 are splined together. The transmission sleeve 420 is sleeved on the outside of the lead screw 200. The transmission sleeve 420 and the lead screw 200 are circumferentially fixed by splined connection, non-circular hole or non-circular segment connection, or integral molding. Thus, the ring gear 414 can be connected to the lead screw 200 through the transmission sleeve 420, that is, the ring gear 414 can drive the lead screw 200 to rotate through the transmission sleeve 420. In this embodiment, the lead screw 200 includes a smooth shaft section and a threaded section. The smooth shaft section passes through the sun gear 411 and rotates with it, allowing the lead screw 200 to rotate relative to the sun gear 411. The threaded section is threadedly connected to the transmission nut 320. The smooth shaft section and the threaded section are integrally formed or separately formed and then assembled and fixed. The motor is connected to the sun gear 411 through a worm gear mechanism, so that the sun gear 411 is driven to rotate by the motor. The brake sleeve 430 is sleeved on the outside of the gear ring 414 and is fixedly connected to the planetary carrier 413. The brake sleeve 430 and the planetary carrier 413 are circumferentially fixed by spline connection. The brake torsion spring 440 is sleeved on the outside of the brake sleeve 430. The brake torsion spring 440 has a release state to release the circumferential braking of the brake sleeve 430 and a locking state to apply circumferential braking to the brake sleeve 430 under normal conditions. When the brake torsion spring 440 is in the locked state, the planetary carrier 413 is circumferentially locked. When the brake torsion spring 440 is in the released state, the planetary carrier 413 can rotate freely. The brake torsion spring 440 can be switched from the locked state to the released state by operating the release component 500.

[0060] When the brake torsion spring 440 is in the locked state, the planetary carrier 413 cannot rotate because it is circumferentially locked. At this time, the clutch 400 is in a state of maintaining the power transmission between the actuation unit 100 and the lead screw 200. The actuation torque of the motor is input through the sun gear 411, and then output through the ring gear 414 after being transmitted by the planetary gear 412. The ring gear 414 drives the lead screw 200 to rotate through the transmission sleeve 420. When the brake torsion spring 440 is released by operating the release component 500, the circumferential lock on the brake sleeve 430 is released, so the planetary carrier 413 can rotate freely. In this case, the planetary gear set 410 will not transmit power, that is, the clutch 400 cuts off the power transmission between the actuation unit 100 and the lead screw 200, thereby activating the release function of the linear actuator.

[0061] like Figure 5 As shown, the linear actuator in this embodiment also includes a first housing 800, a clutch 400 installed inside the first housing 800, and a brake torsion spring 440 normally held tightly against the outside of the brake sleeve 430. The brake torsion spring 440 includes a first pin 441 and a second pin (not shown) fixed on the first housing 800. The release component 500 is used to pull the first pin 441 to expand the brake torsion spring 440, thereby releasing the brake sleeve 430 and releasing the circumferential braking of the brake sleeve 430. In this way, both the brake sleeve 430 and the planetary carrier 413 can rotate circumferentially, thereby activating the rapid release function.

[0062] like Figure 1 , Figure 4 and Figure 5As shown, the release component 500 includes a cable 510 and a release plate 520. Two mounting plates 810 are circumferentially spaced on the outer side of the first housing 800. Both mounting plates 810 extend along the axis of the lead screw 200. Each mounting plate 810 has a limiting groove 811 that is closed at the lower end and open at the upper end. The limiting groove 811 extends through the mounting plate 810 along its thickness direction. The release plate 520 is located outside the first housing 800, and both ends of the release plate 520 are slidably engaged with the two limiting grooves 811, so that the release plate 520 can slide relative to the first housing 800. Positioning pins 820 are also embedded on the two mounting plates 810. The positioning pins 820 are located between the release plate 520 and the groove of the limiting groove 811 to prevent the end of the release plate 520 from coming out of the limiting groove 811. In this embodiment, the release plate 520 is a flat plate, so its sliding path is a straight line. The first housing 800 has a through hole for the first pin 441 to pass through. The release plate 520 is connected to the first pin 441. The first pin 441 is normally in the first position. At this time, the brake torsion spring 440 hugs the brake sleeve 430 and the brake torsion spring 440 is in a locked state. By driving the first pin 441 to move in the opposite direction of its rotation through the release plate 520, the brake torsion spring 440 can be expanded to release the brake sleeve 430. At this time, the brake torsion spring 440 is in a released state.

[0063] The cable 510 extends along the axis of the lead screw 200 towards the inner tube 310. The lower end of the cable 510 is connected to the release plate 520. The release plate 520 has a guide groove 521, which is an inclined groove extending axially along the lead screw 200. The cable 510 has a transmission pin 511 that inserts into and slides within the guide groove 521. When the transmission pin 511 engages with the lower end of the guide groove 521 (e.g., ...), ... Figure 5 As shown), the first pin 441 is in the first position. At this time, the upper end of the guide groove 521 extends obliquely in the same direction as the rotation of the brake torsion spring 440. For example, in this embodiment, the brake torsion spring 440 is left-handed, so the upper end of the guide groove 521 is located to the left of the lower end of the guide groove 521, and the upper end of the guide groove 521 extends obliquely to the left. When the quick release function needs to be activated, the release plate 520 can be driven to move to the right by applying an axial traction force to the cable 510 to move it upward, so that the first pin 441 rotates in the direction of loosening the brake torsion spring 440, thereby releasing the brake sleeve 430 by the brake torsion spring 440, and then releasing the lead screw 200. When the cable 510 is released, the first pin 441 returns to the first position under the restoring force of the brake torsion spring 440 itself, so that the brake torsion spring 440 re-clamps the brake sleeve 430 to perform circumferential braking on the brake sleeve 430.

[0064] To ensure that the first pin 441 can return to the first position after the cable 510 is released, the cable 510 in this embodiment is fitted with a return spring 512. The cable 510 is provided with a limiting part. The linear actuator also includes a housing covering the brake arm 610 and the outside of the cable 510. The return spring 512 is a compression spring. Its end near the release plate 520 abuts against the limiting part, and its end away from the release plate 520 abuts against the limiting block on the inner side of the housing. In this way, after the cable 510 is pulled, the return spring 512 is compressed. When the cable 510 is released, the return spring 512 can drive the cable 510 to return through the limiting part, thereby causing the release plate 520 to drive the first pin 441 to return to the first position, so that the brake torsion spring 440 can re-clamp the brake sleeve 430 to perform circumferential braking on the brake sleeve 430.

[0065] Therefore, when rapid release is required, the release function can be activated by operating the release component 500 to drive the clutch 400 to cut off the power transmission between the actuation unit 100 and the lead screw 200. This allows the lead screw 200 to rotate under load, thereby driving the tubular telescopic component 300 to release rapidly. Under heavy load, if the tubular telescopic component 300 releases too quickly, it will damage the load.

[0066] like Figure 1 , Figure 2 and Figure 7 As shown, in order to solve the above-mentioned technical problems, the linear actuator in this embodiment further includes a braking unit 600. The braking unit 600 includes at least one braking arm 610 configured as a lever structure along the linear telescopic movement direction of the tubular telescopic member 300. The braking arm 610 includes a driving arm 611 and a clamping arm 612 located on both sides of its fulcrum. After the linear actuator activates the release function, the driving arm 611 responds to the release action of the release member 500 and drives the clamping arm 612 to frictionally engage with the outer surface of the tubular telescopic member 300 (i.e., the outer surface of the inner tube 310) to control the release speed of the tubular telescopic member 300 under the action of load force.

[0067] In this embodiment, after the linear actuator is activated and its release function is activated, the lead screw 200 will rotate freely. The release action of the release component 500 drives the drive arm 611 to rotate around the fulcrum. This causes the clamping arm 612 to rotate towards the tubular telescopic component 300 and frictionally engage with the outer surface of the rapidly releasing tubular telescopic component 300. This generates a frictional damping force between the clamping arm 612 and the tubular telescopic component 300, which is opposite to the direction of movement of the tubular telescopic component 300. This reduces the release speed of the tubular telescopic component 300, allowing it to release slowly and preventing damage to the load.

[0068] The linear actuator in this embodiment also includes an outer tube 700 sleeved outside the tubular telescopic component 300. The tubular telescopic component 300 performs linear telescopic movement relative to the outer tube 700. The outer tube 700 has outwardly extending fixed shafts 710 protruding from opposite sides. The brake arm 610 has mounting holes 613 located between the drive arm 611 and the clamping arm 612 on opposite sides. The mounting holes 613 are rotatably engaged with the fixed shafts 710, so that the brake arm 610 is pivotally connected to the outer surface of the outer tube 700 to form a lever structure; that is, the mounting holes 613 form the fulcrum of the brake arm 610. This design, by placing the brake arm 610 outside the outer tube 700, provides sufficient operating space for the assembly of the brake arm 610, thereby facilitating the assembly and disassembly of the brake arm 610.

[0069] It is understood that in other embodiments of this utility model, through holes are provided on opposite sides of the outer tube, and rotating shafts are provided on opposite sides of the brake arm between the drive arm and the clamping arm. The rotating shafts are rotatably engaged with the through holes, so that the brake arm can be pivotally connected to the outer side of the outer tube to form a lever structure.

[0070] like Figure 1 and Figure 3 As shown, the braking unit 600 in this embodiment further includes a transmission guide component 620, which slides axially along the outer tube 700. The release component 500 also includes a sliding sleeve 530 connected to the cable 510. The sliding sleeve 530 is fitted onto the outer tube 700 and guided axially by the outer tube 700. When the cable 510 is pulled, it can drive the sliding sleeve 530 to slide axially along the outer tube 700 towards the brake arm 610. The transmission guide component 620 is independently machined. The end of the transmission guide component 620 and the end of the sliding sleeve 530 away from the release plate 520 are axially abutted and connected, so that after the release component 500 is axially pulled to perform the release action, the sliding sleeve 530 drives the transmission guide component 620 to slide axially away from the release plate 520. At the same time, after the cable 510 is released, the sliding sleeve 530 can drive the transmission guide component 620 to reset. In this embodiment, the independent machining of the transmission guide component 620 simplifies the manufacturing difficulty of the sliding sleeve 530.

[0071] It is understood that in other embodiments of this utility model, the transmission guide component and the sliding sleeve form an integral structure.

[0072] In this embodiment, after the transmission guide component 620 slides axially away from the release plate 520, it can convert the axial traction force of the release component 500 into a radial driving force on the drive arm 611, thereby driving the drive arm 611 radially away from the outer surface of the outer tube 700. Since the existing release component 500 performs the release action under axial traction, by setting the transmission guide component 620 to convert the axial traction force of the release component 500 into a radial driving force on the drive arm 611 to drive the drive arm 611 radially away from the outer surface of the outer tube 700, the traction direction of the existing release component 500 can be maintained without changing it, thereby reducing the degree of product modification and thus reducing the product modification cost.

[0073] In this embodiment, the outer peripheral surface of the transmission guide component 620 is provided with a guide slider 621, and the inner side of the drive arm 611 is provided with a guide groove 6110. The guide groove 6110 is constructed as a wedge-shaped groove, and the depth of the guide groove 6110 gradually decreases towards the fulcrum. The guide slider 621 is constructed as a wedge-shaped block, and the side of the guide slider 621 facing away from the outer tube 700 has an inclined surface that gradually approaches the outer surface of the outer tube 700 towards the fulcrum. This design facilitates the insertion and engagement of the guide slider 621 and the guide groove 6110. When the transmission guide component 620 slides axially toward the fulcrum, the guide slider 621 inserts into the guide groove 6110 and moves axially relative to the guide groove 6110 as the transmission guide component 620 continues to slide. This drives the drive arm 611 further away from the outer surface of the outer tube 700. That is, as the release stroke of the release component 500 increases, the rotation angle of the brake arm 610 also gradually increases, and the drive arm 611 moves further away from the outer surface of the outer tube 700 to ensure that the clamping arm 612 can frictionally engage with the outer surface of the inner tube 310. Alternatively, after the clamping arm 612 frictionally engages with the outer surface of the inner tube 310, the drive arm 611 is pushed further to increase the clamping force of the clamping arm 612 on the inner tube 310, thereby increasing the friction damping force.

[0074] It is understood that in other embodiments of the present invention, the guide groove is configured as a wedge-shaped groove; or the guide slider is configured as a wedge-shaped block.

[0075] It is understood that in other embodiments of the present invention, the guide groove is provided on the outer periphery of the transmission guide component, and the guide slider protrudes on the inner side of the drive arm. The guide groove is configured as a wedge-shaped groove, and / or the guide slider is configured as a wedge-shaped block.

[0076] In this embodiment, the transmission guide component 620 is constructed as a sleeve structure corresponding to the shape of the outer side of the outer tube 700. The transmission guide component 620 is fitted onto the outer tube 700 and is guided by the outer tube 700 to slide axially. This design can improve the assembly reliability of the transmission guide component 620 and the outer tube 700, prevent the transmission guide component 620 from falling off, and simplify the disassembly and assembly of the transmission guide component 620.

[0077] In this embodiment, the length of the drive arm 611 is greater than the length of the clamping arm 612. This design allows the brake arm 610 to form a force-saving lever structure, thereby reducing the radial outward thrust exerted by the transmission guide component 620 on the drive arm 611 while keeping the clamping force of the clamping arm 612 on the tubular telescopic component 300 constant. This reduces the stress on the drive arm 611 and prevents it from deforming or breaking due to excessive stress.

[0078] like Figure 2 , Figure 8 and Figure 10 As shown, in this embodiment, the linear movement of the tubular telescopic component 300 in the first direction is defined as the working stroke, and the linear movement of the tubular telescopic component 300 under load force in the second direction opposite to the first direction is defined as the release stroke, i.e., the first direction is upward and the second direction is downward. The clamping arm 612 has a clamping surface 6120 facing the outer surface of the tubular telescopic component 300. The clamping surface 6120 gradually deviates from the outer surface of the tubular telescopic component 300 along the first direction, and a gap 001 with a radially increasing distance is formed between the clamping surface 6120 and the outer surface of the tubular telescopic component 300 along the first direction. After the linear actuator activates the release function, the clamping surface 6120 gradually approaches and contacts the outer surface of the tubular telescopic component 300 as the rotation angle of the brake arm 610 increases (e.g., ...). Figure 13 (As shown).

[0079] In this embodiment, the clamping surface 6120 is a conical surface that is larger at the top and smaller at the bottom, so that the contact area between the clamping surface 6120 and the outer surface of the tubular telescopic component 300 increases as the rotation angle of the brake arm 610 increases. With this design, the contact area between the clamping surface 6120 and the outer surface of the tubular telescopic component 300 can be controlled by controlling the release stroke of the release component 500. The larger the contact area, the better the deceleration effect on the tubular telescopic component 300, and thus the release speed of the tubular telescopic component 300 can be adjusted at any time as needed.

[0080] It is understood that in other embodiments of this utility model, the inner side of the clamping arm is provided with an elastic friction block. After the clamping arm contacts the inner tube, the clamping force of the clamping arm on the inner tube is increased by continuing to push the driving arm, so as to deform the elastic friction block and increase the contact area with the inner tube, thereby improving the friction damping force.

[0081] Secondly, the braking unit 600 in this embodiment includes two braking arms 610, which are distributed on opposite sides of the tubular telescopic member 300. Each braking arm 610 is a thin plate structure that partially conforms to the outer surface of the outer tube 700, making the overall structure more compact. By providing two braking arms 610, the frictional contact area between the braking unit 600 and the tubular telescopic member 300 is increased, thereby improving the frictional damping force on the tubular telescopic member 300 and thus enhancing the deceleration effect. This allows the tubular telescopic member 300 to release at a lower speed.

[0082] It is understood that in other embodiments of this utility model, a brake arm may be provided in order to simplify the structure of the braking unit.

[0083] Furthermore, the braking unit 600 in this embodiment also includes an elastic component 630, which is an elastic sleeve fitted on the outside of the two driving arms 611. The elastic sleeve drives the two driving arms 611 to maintain a force state close to each other, so that the two clamping arms 612 maintain a force state far from each other. With this design, when the release function is not activated, the two clamping arms 612 can avoid contact with the outer surface of the inner tube 310. Thus, when the actuation unit 100 drives the lead screw 200 to rotate and the tubular telescopic component 300 to perform linear telescopic movement, the braking unit 600 can avoid applying frictional damping force to the telescopic movement of the tubular telescopic component 300, thereby reducing the output power consumption of the actuation unit 100.

[0084] It is understood that in other embodiments of this utility model, the elastic component may also be connected to an elastic rope between the two drive arms, and the two drive arms may be driven to maintain a force state close to each other, so that the two clamping arms may maintain a force state far away from each other.

[0085] It is understood that in other embodiments of this utility model, the elastic component may also be connected to a compression spring between the two clamping arms, the compression spring keeping the two clamping arms in a force state that keeps them away from each other.

[0086] Finally, for ease of understanding, the working process will be described using the example of the linear actuator being configured as a drive actuator in this embodiment:

[0087] like Figure 8 and Figure 10As shown, under normal conditions, the brake torsion spring 440 applies circumferential braking to the planetary carrier 413, preventing the planetary carrier 413 from rotating. At this time, the clutch 400 is in a state of maintaining power transmission between the actuation unit 100 and the lead screw 200. Since the release component 500 does not perform a release action, the two clamping arms 612 do not contact the outer surface of the inner tube 310. The actuation torque of the motor is input through the sun gear 411, and after being transmitted through the planetary gear 412, it is output by the gear ring 414. The gear ring 414 drives the lead screw 200 to rotate through the transmission sleeve 420 to control the extension and retraction of the tubular telescopic component 300. At this time, the load can be pushed away from the actuation unit 100 by driving the tubular telescopic component 300.

[0088] like Figures 11 to 13 As shown, when the brake torsion spring 440 is released by operating the release component 500, the clutch 400 cuts off the power transmission between the actuation unit 100 and the lead screw 200. As a result, the linear actuator activates the release function, and the tubular telescopic component 300 is released towards the actuation unit 100 by the load thrust. By controlling the release stroke of the release component 500, the frictional engagement of the clamping arm 612 with the outer surface of the tubular telescopic component 300 and the contact area between the clamping arm 612 and the outer surface of the tubular telescopic component 300 can be controlled to provide frictional damping force against the load thrust, so that the load can be released slowly.

[0089] It is understood that in other embodiments of this utility model, when the linear actuator is configured as a pull actuator, the tubular telescopic component pulls the load toward the actuation unit. After the linear actuator activates the release function, the tubular telescopic component is released away from the actuation unit by the load pull force. The clamping arm frictionally engages with the outer surface of the tubular telescopic component, providing frictional damping force against the load pull force.

[0090] It should be noted that in the embodiments of this utility model, the clutch is designed based on a planetary gear set, wherein the release component is specifically constructed to pull the brake torsion spring, thereby releasing the power transmission between the planetary gear set and the lead screw. However, this utility model is not limited to this design; the clutch can also adopt other known structures to achieve the function of maintaining or cutting off the power transmission between the actuating unit and the lead screw. For example, the clutch mechanism implemented by the clutch sleeve and the left connecting piece as described in CN214367368U can be referred to, in which the release component activates the release operation by causing the clutch sleeve to move axially; another example is the clutch mechanism of the clutch and worm gear as disclosed in CN118391414A, in which the release component also triggers the release function by guiding the axial displacement of the clutch sleeve.

[0091] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Those skilled in the art should understand that this utility model includes, but is not limited to, the content described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of this utility model will be included within the scope of the claims.

Claims

1. A safety-release linear actuator, comprising: An actuation unit that provides actuating torque; A lead screw that is driven to rotate by an actuating torque; A tubular telescopic component is fitted outside the lead screw and is driven by the rotational motion of the lead screw to perform linear telescopic motion; A clutch is used to maintain or disconnect the power transmission between the actuator and the lead screw. An operable release component that drives the clutch to cut off the power transmission between the actuator unit and the lead screw, thereby activating the release function of the linear actuator; The linear actuator is characterized in that it further includes: A braking unit includes at least one brake arm configured as a lever along the linear telescopic movement direction of a tubular telescopic member, the brake arm including a clamping arm and a driving arm located on both sides of its fulcrum. After the linear actuator activates the release function, the drive arm responds to the release action of the release component and drives the clamping arm to frictionally engage with the outer surface of the tubular telescopic component, thereby controlling the release speed of the tubular telescopic component under load.

2. The linear actuator with safe release as described in claim 1, characterized in that, The linear actuator is configured as a push actuator, and the tubular telescopic component pushes the load away from the actuation unit. After the linear actuator activates the release function, the tubular telescopic component is released towards the actuation unit by the load thrust. The clamping arm frictionally engages with the outer surface of the tubular telescopic component to provide frictional damping force against the load thrust.

3. The linear actuator with safe release as described in claim 1, characterized in that, The linear actuator is configured as a pull actuator, in which the tubular telescopic component pulls the load toward the actuation unit. After the linear actuator activates the release function, the tubular telescopic component is released away from the actuation unit by the load pull force. The clamping arm frictionally engages with the outer surface of the tubular telescopic component, providing frictional damping force to resist the load pull force.

4. The linear actuator with safe release as described in claim 1, characterized in that, The linear actuator includes an outer tube sleeved outside the tubular telescopic component, the tubular telescopic component performs linear telescopic movement relative to the outer tube, and the brake arm is pivotally connected to the outer side of the outer tube to form a lever structure.

5. The linear actuator with safe release as described in claim 4, characterized in that, The braking unit also includes a transmission guide component that slides back and forth along the axial direction of the outer tube. The release component is axially pulled to perform a release action. The transmission guide component is used to convert the axial pulling force of the release component into a radial driving force on the drive arm, which is used to drive the drive arm radially away from the outer side of the outer tube.

6. The linear actuator with safe release as described in claim 5, characterized in that, One of the transmission guide component and the drive arm is provided with a guide groove, and the other is provided with a guide slider. The guide slider and the guide groove move axially relative to each other as the transmission guide component slides. The guide groove is configured as a wedge-shaped groove and / or the guide slider is configured as a wedge-shaped block.

7. The safe-release linear actuator as described in claim 6, characterized in that, The transmission guide component is constructed as a sleeve structure corresponding to the shape of the outer side of the outer tube. The transmission guide component is fitted onto the outer tube and is guided by the outer tube to slide axially.

8. The safe-release linear actuator as described in claim 7, characterized in that, The release component includes a cable and a sleeve connecting the cable. The sleeve is fitted onto an outer tube and guided to slide axially by the outer tube. The axial sliding of the sleeve comes from the traction of the cable. The transmission guide component is axially opposed to the sleeve or forms an integral structure with the sleeve.

9. The linear actuator with safe release as described in claim 1, characterized in that, The linear movement of the tubular telescopic component in a first direction is defined as the working stroke, and the linear movement of the tubular telescopic component under load in a second direction opposite to the first direction is defined as the release stroke. The clamping arm has a clamping surface facing the outer surface of the tubular telescopic component. The clamping surface gradually deviates from the outer surface of the tubular telescopic component along the first direction. A gap with a radially increasing distance is formed between the clamping surface and the outer surface of the tubular telescopic component along the first direction. After the linear actuator activates the release function, the clamping surface gradually approaches and contacts the outer surface of the tubular telescopic component as the rotation angle of the brake arm increases.

10. The safe-release linear actuator as described in claim 9, characterized in that, The contact area between the clamping surface and the outer surface of the tubular telescopic component increases as the rotation angle of the brake arm increases, and the rotation angle of the brake arm increases as the release stroke of the release component increases.

11. The linear actuator with safe release as claimed in claim 1, characterized in that, The length of the drive arm is greater than the length of the clamping arm.

12. The linear actuator with safe release as claimed in claim 1, characterized in that, The braking unit includes two braking arms configured as a cross lever structure along the linear telescopic movement direction of the tubular telescopic component, with the two braking arms distributed on opposite sides of the tubular telescopic component.

13. The safe-release linear actuator as described in claim 12, characterized in that, The braking unit also includes an elastic component that connects two braking arms, keeping the two clamping arms in a force state that keeps them away from each other.

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