Secure release linear actuator

Abstract

The invention discloses a linear actuator capable of being safely released. 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 invention can realize slow release.

Description

[Technical field]

[0001] The invention relates to the technical field of linear actuators, in particular to a linear actuator with safe release. [Background technology]

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

[0003] Combined with the application environment of the linear actuator, when the linear actuator encounters a motor failure, or a power outage or other situations where power needs to be cut off, in order to be able to release the tubular telescopic component and retract it, a clutch and an operable release component are usually added, wherein the clutch is used to maintain or cut off the power transmission between the actuating unit and the screw rod. By operating the release component, the clutch can be driven to cut off the power transmission between the actuating unit and the screw rod and activate the release function, so that the screw rod can rotate under the action of the load and drive the tubular telescopic component to move quickly for release. The greater the load, the greater the release speed of the tubular telescopic component. When it is used as a push actuator on an electric bed, rapid release above a certain weight may cause harm to the user; when it is used as a pulling actuator in the lifting field, the descending speed will be very fast when a large load is quickly released, thereby causing damage to the load, or objects or people below. [Summary of the invention]

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a safe-release linear actuator capable of controlling the release speed of a tubular telescopic component under the action of a load force so that it can be released slowly.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] Linear actuator with safety release, including:

[0007] an actuating unit providing an actuating torque;

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

[0009] A tubular telescopic component, which is sleeved outside the screw and driven by the rotational movement of the screw to perform linear telescopic movement;

[0010] A clutch, which is used to maintain or cut off the power transmission between the actuating unit and the screw;

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

[0012] The linear actuator further comprises:

[0013] A brake unit, comprising at least one brake arm configured as a lever structure along the linear telescopic movement direction of the tubular telescopic member, the brake arm comprising a clamping arm and a driving arm located on both sides of the 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 to control the release speed of the tubular telescopic component under the load force.

[0015] After the release function of the linear actuator in the present invention is activated, the screw will rotate freely, and the release action of the release component will drive the driving arm to rotate around the fulcrum, which can drive the clamping arm to rotate in the direction close to the tubular telescopic component and frictionally engage with the outer surface of the quickly released tubular telescopic component, so that a friction damping force opposite to the movement direction of the tubular telescopic component is generated between the clamping arm and the tubular telescopic component, thereby reducing the release speed of the tubular telescopic component and allowing the tubular telescopic component to be released slowly to avoid damage to the load.

[0016] In the above-mentioned safe release linear actuator, the linear actuator is configured as a push actuator, and the tubular telescopic component pushes the load in a direction away from the actuator unit. After the linear actuator activates the release function, the tubular telescopic component is released in a direction close to the actuator unit due to the load thrust, and the clamping arm frictionally engages with the outer surface of the tubular telescopic component to provide a friction damping force to counteract the load thrust.

[0017] In the above-mentioned safe release linear actuator, the linear actuator is configured as a pulling actuator, and the tubular telescopic component pulls the load in a direction close to the actuating unit. After the linear actuator activates the release function, the tubular telescopic component is released in a direction away from the actuating unit due to the load pulling force, and the clamping arm frictionally engages with the outer surface of the tubular telescopic component to provide a friction damping force to counteract the load pulling force.

[0018] In the above-mentioned safety release linear actuator, the linear actuator includes an outer tube sleeved on the outside of 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. In this design, by locating the brake arm outside the outer tube, sufficient operating space can be provided for the assembly of the brake arm, thereby facilitating the disassembly and assembly of the brake arm.

[0019] In the above-mentioned safe release linear actuator, the brake unit further includes a transmission guide component that slides back and forth along the axial direction of the outer tube, the release component is pulled axially to implement the release action, and 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 surface of the outer tube. Since the existing release component implements the release action under the action of axial pulling, the transmission guide component is provided to convert the axial pulling force of the release component into a radial driving force of the drive arm to drive the drive arm radially away from the outer side surface of the outer tube, and it is unnecessary to change the pulling direction of the existing release component, so as to reduce the degree of modification of the product, thereby reducing the modification cost of the product.

[0020] In the above-mentioned safe release linear actuator, one of the transmission guide component and the driving arm is provided with a guide groove, and the other is provided with a guide slider, and the guide slider and the guide groove generate axial relative movement as the transmission guide component slides, and the guide groove is configured as a wedge-shaped groove and / or the guide slider is configured as a wedge-shaped block. Such a design not only facilitates the plug-in cooperation between the guide slider and the guide groove, but also gradually increases the rotation angle of the brake arm as the release stroke of the release component increases, even if the transmission guide component drives the driving arm further away from the outer side of the outer tube, so as to ensure that the clamping arm can 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 clamping arm can continue to push the driving arm so that the clamping force on the tubular telescopic component is greater, thereby increasing the friction damping force.

[0021] In the above-mentioned safe release linear actuator, the transmission guide component is constructed as a sleeve structure corresponding to the shape of the outer side surface of the outer tube, and the transmission guide component is sleeved on the outer tube and guided by the outer tube to slide axially. Such a design can not only improve the assembly reliability of the transmission guide component and the outer tube, prevent the transmission guide component from falling off, but also simplify the difficulty of disassembling and assembling the transmission guide component.

[0022] In the above-mentioned safety release linear actuator, the release component includes a cable and a sleeve connected to the cable, the sleeve is sleeved on the outer tube and guided by the outer tube to slide axially, the axial sliding of the sleeve comes from the traction of the cable, and the transmission guide component is axially against the sleeve or forms an integral structure with the sleeve. In this design, pulling the cable can pull the sleeve to slide, so that the sleeve drives the transmission guide component to slide, and the structure is simple.

[0023] In the above-mentioned safe release linear actuator, the linear movement of the tubular telescopic component in a first direction is defined as a working stroke, and the linear movement of the tubular telescopic component in a second direction opposite to the first direction under the load force is defined as a release stroke. The clamping arm has a clamping surface facing the outer surface of the tubular telescopic component, and the clamping surface gradually deviates from the outer surface of the tubular telescopic component along the first direction. A gap with a radial spacing that increases unidirectionally 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 above-mentioned safe release linear actuator, 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. With such a design, the contact area between the clamping surface and the outer surface of the tubular telescopic component can be controlled by controlling the release stroke of the release component. The larger the contact area, the better the deceleration effect on the tubular telescopic component, thereby the release speed of the tubular telescopic component can be adjusted at any time according to needs.

[0025] In the above-mentioned safe release linear actuator, the length of the driving arm is greater than the length of the clamping arm. With such a design, the brake arm can form a force-saving lever structure, so as to reduce the radial outward thrust exerted by the transmission guide component on the driving arm while keeping the squeezing force of the clamping arm on the tubular telescopic component unchanged, thereby reducing the force on the driving arm and preventing the driving arm from being deformed or broken due to excessive force.

[0026] In the above-mentioned safe release linear actuator, the brake unit includes two brake arms configured as a cross lever structure along the linear telescopic movement direction of the tubular telescopic component, and the two brake arms are distributed on two opposite sides of the tubular telescopic component. Such a design can increase the friction engagement area between the brake unit and the tubular telescopic component, thereby increasing the friction damping force on the tubular telescopic component, thereby improving the deceleration effect, and allowing the tubular telescopic component to be released at a lower speed.

[0027] In the above-mentioned safe release linear actuator, the brake unit further comprises an elastic component, which connects the two brake arms so as to keep the two clamping arms in a force state away from each other. With such a design, when the release function is not activated, that is, when the actuator unit drives the screw rod to rotate and the tubular telescopic component performs a linear telescopic motion, the elastic component keeps the two clamping arms in a force state away from each other, thereby preventing the clamping arms from contacting and engaging with the outer surface of the tubular telescopic component, thereby preventing the brake unit from applying a friction damping force to the telescopic motion of the tubular telescopic component, and reducing the output power consumption of the actuator unit.

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

Brief Description of the Drawings

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

[0030] Figure 1 is an exploded schematic diagram of a linear actuator in Embodiment 1 of the present invention;

[0031] Figure 2 It is a schematic structural diagram of a brake arm in Embodiment 1 of the present invention;

[0032] Figure 3 Schematic diagram of the structure of the transmission guide component in the first embodiment of the present invention;

[0033] Figure 4 The structure of the linear actuator in the first embodiment of the present invention is shown in FIG. Figure 1 ;

[0034] Figure 5 for Figure 4 A is a partial enlarged schematic diagram;

[0035] Figure 6 The structure of the linear actuator in the first embodiment of the present invention is shown in FIG. Figure 2 ;

[0036] Figure 7 for Figure 6 A partial enlarged schematic diagram of B in the middle;

[0037] Figure 8 is a cross-sectional view of the linear actuator in the first embodiment of the present invention when the release function is not activated;

[0038] Fig. 9 for Figure 8 A partial enlarged schematic diagram of C in the middle;

[0039] Fig.10 for Figure 8 A partial enlarged schematic diagram of D in the middle;

[0040] Fig.11 is a cross-sectional view of the linear actuator in the first embodiment of the present invention when the release function is activated;

[0041] Fig.12 for Fig.11 A partial enlarged schematic diagram of middle E;

[0042] Fig.13 for Fig.11 A partial enlarged schematic diagram of F in the middle.

[0043] Reference numerals:

[0044] 001, gap;

[0045] 100, actuating unit; 200, lead screw; 300, tubular telescopic member; 310, inner tube; 320, transmission nut; 400, clutch; 410, planetary gear set; 411, sun gear; 412, planetary gear; 413, planet carrier; 414, ring gear; 420, transmission sleeve; 430, brake sleeve; 440, brake torsion spring; 441, first pin; 500, release member; 510, cable; 511, transmission pin; 512, return spring; 520, release plate; 521, guide groove; 530, sliding sleeve; 600, brake unit; 610, brake 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 shell; 810, mounting plate; 811, limit groove; 820, limit pin. [Specific implementation method]

[0046] The present invention provides a linear actuator with safety release, comprising:

[0047] an actuating unit providing an actuating torque;

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

[0049] A tubular telescopic component, which is sleeved outside the screw and driven by the rotational movement of the screw to perform linear telescopic movement;

[0050] A clutch, which is used to maintain or cut off the power transmission between the actuating unit and the screw;

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

[0052] The linear actuator further comprises:

[0053] A brake unit, comprising at least one brake arm configured as a lever structure along the linear telescopic movement direction of the tubular telescopic member, the brake arm comprising a clamping arm and a driving arm located on both sides of the 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 to control the release speed of the tubular telescopic component under the load force.

[0055] After the release function of the linear actuator in the present invention is activated, the screw will rotate freely, and the release action of the release component will drive the driving arm to rotate around the fulcrum, which can drive the clamping arm to rotate in the direction close to the tubular telescopic component and frictionally engage with the outer surface of the quickly released tubular telescopic component, so that a friction damping force opposite to the movement direction of the tubular telescopic component is generated between the clamping arm and the tubular telescopic component, thereby reducing the release speed of the tubular telescopic component and allowing the tubular telescopic component to be released slowly to avoid damage to the load.

[0056] The technical solutions of the embodiments of the present invention are explained and illustrated below in conjunction with the drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, not all of them. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work all belong to the protection scope of the present invention. In addition, it should be understood that the following words indicating orientation or position relationship such as "up", "down", "left", "right", "longitudinal", "lateral", "inside", "outside", "vertical", "horizontal", "top", "bottom", etc. are only based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device / element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0057] Embodiment 1

[0058] like Figures 1 to 13 As shown, the safe release linear actuator in this embodiment includes an actuating unit 100, a screw rod 200, a tubular telescopic component 300, a clutch 400 and an operable release component 500, wherein the actuating unit 100 is a motor that can provide an actuating torque, the tubular telescopic component 300 includes an inner tube 310 and a transmission nut 320, the inner tube 310 is sleeved on the outer side of the screw rod 200, and the outer end of the screw rod 200 close to the actuating unit 100 is threadedly connected with the transmission nut 320, the transmission nut 320 is fixed circumferentially and axially relative to the inner tube 310, and the clutch 400 is used to maintain or cut off the connection between the actuating unit 100 and the screw rod 200. Power transmission, the release component 500 is used to drive the clutch 400 to cut off the power transmission between the actuating unit 100 and the screw rod 200 and activate the release function of the linear actuator. When the linear actuator is in the state of not activating the release function, the clutch 400 maintains the power transmission state between the actuating unit 100 and the screw rod 200. At this time, the actuating torque provided by the motor can be transmitted to the screw rod 200 through the clutch 400, thereby driving the screw rod 200 to rotate. The rotation of the screw rod 200 drives the transmission nut 320 to drive the inner tube 310 to perform linear displacement along the axial direction of the screw rod 200, thereby driving the tubular telescopic component 300 to perform linear telescopic movement.

[0059] Specifically, Fig. 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, wherein the planetary gear set 410 includes a sun gear 411, a planetary gear 412, a planetary carrier 413 and a ring gear 414, the planetary gear 412 is rotatably mounted on the planetary carrier 413, a plurality of planetary gears 412 surround the outer side of the sun gear 411 and mesh with the sun gear 411, the ring gear 414 surrounds the outer side of a plurality of planetary gears 412 and meshes with the planetary gears 412, the transmission sleeve 420 and the ring gear 414 are splined, the transmission sleeve 420 is sleeved on the outer side of the screw rod 200, the transmission sleeve 420 and the screw rod 200 are splined or non-circular holes or non-circular segments are matched or integrally formed to achieve circumferential relative fixation of the two, thereby enabling the ring gear 414 to be transmission-connected to the screw rod 200 through the transmission sleeve 420, that is, the ring gear 414 can drive the screw rod 200 to rotate through the transmission sleeve 420. The lead screw 200 in this embodiment includes an optical axis section and a threaded section, the optical axis section passes through the sun gear 411 and rotates with the sun gear 411, so that the lead screw 200 can rotate relative to the sun gear 411, the threaded section is threadedly connected to the transmission nut 320, the optical axis section and the threaded section are integrally processed or the two are separately processed 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, and the brake sleeve 430 is sleeved on the outside of the gear ring 414, and the brake sleeve 430 is fixedly connected or connected to the planet carrier 413. The brake sleeve 430 and the planetary carrier 413 are relatively fixed in the circumferential direction by spline cooperation. The brake torsion spring 440 is sleeved on the outside of the brake sleeve 430. The brake torsion spring 440 has a release state for releasing the circumferential braking of the brake sleeve 430 and a locked state for applying 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 a locked state, the planet carrier 413 cannot rotate because the planet carrier 413 is circumferentially locked. At this time, the clutch 400 is in a state of maintaining the power transmission between the actuating unit 100 and the screw 200. The actuating torque of the motor is input through the sun gear 411, and then output by the ring gear 414 after being transmitted by the planet gear 412. The ring gear 414 drives the screw 200 to rotate through the transmission sleeve 420. When the brake torsion spring 440 is in a released state by operating the release component 500, the planet carrier 413 can rotate freely because the circumferential locking of the brake sleeve 430 is released. In this case, the planetary gear set 410 will not transmit power, that is, the clutch 400 cuts off the power transmission between the actuating unit 100 and the 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, the clutch 400 is installed in the first housing 800, and the brake torsion spring 440 is normally clamped to the outside of the brake sleeve 430. The brake torsion spring 440 includes a first pin 441 and a second pin (not shown in the figure) fixed to 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, so as to release 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 quick release function.

[0062] like Figure 1 , Figure 4 and Figure 5 As shown, the release component 500 includes a cable 510 and a release plate 520. Two mounting plates 810 are circumferentially spaced apart on the outer side of the first shell 800. The two mounting plates 810 extend along the axis of the screw rod 200. Each mounting plate 810 is provided with a limiting groove 811 which is closed at the lower end and open at the upper end. The limiting groove 811 penetrates the mounting plate 810 along the thickness direction of the mounting plate 810. The release plate 520 is located on the outer side of the first shell 800, and the two ends of the release plate 520 are respectively slidably matched with the two limiting grooves 811 so that the release plate 520 can slide relative to the first shell 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 notch of the limiting groove 811 to prevent the end of the release plate 520 from slipping out of the limiting groove 811. The release plate 520 in this embodiment is a flat plate, so its sliding path is a straight line. The first shell 800 is provided with a through hole for the first pin 441 to pass through, and the release plate 520 is connected to the first pin 441. The first pin 441 is in the first position under normal circumstances. At this time, the brake torsion spring 440 holds the brake sleeve 430 tightly, and the brake torsion spring 440 is in a locked state; the first pin 441 is driven to move in the direction opposite to its rotation direction by the release plate 520, so that the brake torsion spring 440 can expand outward and release the brake sleeve 430, and the brake torsion spring 440 is in a released state.

[0063] The cable 510 extends along the axis of the screw rod 200 in the direction in which the inner tube 310 extends. The lower end of the cable 510 is connected to the release plate 520. The release plate 520 is provided with a guide groove 521. The guide groove 521 is an inclined groove extending along the axial direction of the screw rod 200 and arranged obliquely. The cable 510 is provided with a transmission pin 511 inserted into the guide groove 521 and slidingly matched with the guide groove 521. When the transmission pin 511 is matched with the lower end of the guide groove 521 (such as Figure 5), the first pin 441 is in the first position, at which time the upper end of the guide slot 521 extends obliquely in the same direction as the rotation direction of the brake torsion spring 440. For example, if the brake torsion spring 440 in this embodiment is left-handed, the upper end of the guide slot 521 is located on the left side of the lower end of the guide slot 521, and the corresponding upper end of the guide slot 521 extends obliquely to the left. When the quick release function needs to be activated, the release plate 520 can be driven to move rightward by applying axial traction 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, so that the brake torsion spring 440 releases the brake sleeve 430, and then releases the lead screw 200. When the cable 510 is released, the first pin 441 is reset to the first position under the restoring force of the brake torsion spring 440 itself, so that the brake torsion spring 440 re-holds the brake sleeve 430 to apply circumferential braking to the brake sleeve 430.

[0064] In order to ensure that the first pin 441 can be reset to the first position after the cable 510 is released, the cable 510 in this embodiment is provided with a reset spring 512, and a limit portion is provided on the cable 510. The linear actuator also includes a shell covering the brake arm 610 and the outer side of the cable 510. The reset spring 512 is a compression spring, and its end close to the release plate 520 is abutted against the limit portion, and the end away from the release plate 520 is abutted against the limit block on the inner side of the shell. In this way, after the cable 510 is pulled, the reset spring 512 is compressed, and when the cable 510 is released, the reset spring 512 can drive the cable 510 to reset through the limit portion, and then the release plate 520 drives the first pin 441 to reset to the first position, so that the brake torsion spring 440 re-holds the brake sleeve 430 to implement circumferential braking on the brake sleeve 430.

[0065] Therefore, when quick 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 actuating unit 100 and the screw rod 200, so that the screw rod 200 can rotate under the action of the load and drive the tubular telescopic component 300 to be released quickly. Under heavy load conditions, the tubular telescopic component 300 will be damaged if it is released too quickly.

[0066] like Figure 1 , Figure 2 and Figure 7As shown, in order to solve the above technical problems, the linear actuator in this embodiment also includes a braking unit 600, which includes at least one braking arm 610 constructed as a lever structure along the linear telescopic movement direction of the tubular telescopic component 300, and 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 component 500 and drives the clamping arm 612 to frictionally engage with the outer surface of the tubular telescopic component 300 (that is, the outer surface of the inner tube 310), so as to control the release speed of the tubular telescopic component 300 under the action of the load force.

[0067] That is, after the release function of the linear actuator in this embodiment is activated, the screw rod 200 will rotate freely, and the release action of the release component 500 will drive the driving arm 611 to rotate around the fulcrum, which can drive the clamping arm 612 to rotate in the direction close to the tubular telescopic component 300 and frictionally engage with the outer surface of the quickly released tubular telescopic component 300, so that a friction damping force opposite to the movement direction of the tubular telescopic component 300 is generated between the clamping arm 612 and the tubular telescopic component 300, thereby reducing the release speed of the tubular telescopic component 300 and allowing the tubular telescopic component 300 to be slowly released to avoid damage to the load.

[0068] The linear actuator in this embodiment further includes an outer tube 700 sleeved on the outside of the tubular telescopic component 300, and the tubular telescopic component 300 performs linear telescopic motion relative to the outer tube 700. The outer tube 700 is provided with fixed shafts 710 extending outward on opposite sides thereof, and the brake arm 610 is provided with mounting holes 613 located between the driving arm 611 and the clamping arm 612 on opposite sides thereof. The mounting holes 613 are rotatably matched with the fixed shaft 710, so that the brake arm 610 is pivotally connected to the outer side 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. With such a design, by making the brake arm 610 located on the outside of the outer tube 700, sufficient operating space can be provided for the assembly of the brake arm 610, thereby facilitating the disassembly and assembly of the brake arm 610.

[0069] It can be understood that in other embodiments of the present invention, through holes are provided on opposite sides of the outer tube, and rotating shafts located between the driving arm and the clamping arm are provided on opposite sides of the brake arm, and the rotating shafts are rotatably matched with the through holes, so that the brake arm can be pivotally connected to the outer side surface of the outer tube to form a lever structure.

[0070] like Figure 1 and Figure 3As shown, the brake unit 600 in this embodiment further includes a transmission guide component 620, which slides back and forth along the axial direction of the outer tube 700. The release component 500 further includes a sleeve 530 connected to the cable 510. The sleeve 530 is sleeved on the outer tube 700 and guided by the outer tube 700 to slide axially. After the cable 510 is pulled, the sleeve 530 can be driven to slide axially along the outer tube 700 toward the direction close to the brake arm 610. The transmission guide component 620 is independently processed and formed. The transmission guide component 620 and the end of the sleeve 530 away from the release plate 520 are axially abutted and connected, so that after the release component 500 is axially pulled to implement the release action, the transmission guide component 620 is driven to slide axially in the direction away from the release plate 520 through the sleeve 530. At the same time, after the cable 510 is released, the transmission guide component 620 can be driven to reset through the sleeve 530. The independent processing of the transmission guide component 620 in this embodiment can simplify the processing and manufacturing difficulty of the sleeve 530.

[0071] It can be understood that in other embodiments of the present invention, the transmission guide component and the sliding sleeve form an integral structure.

[0072] After the transmission guide component 620 in this embodiment slides axially in the direction away from the release plate 520, the axial traction force of the release component 500 can be converted into a radial driving force on the driving arm 611, so as to drive the driving arm 611 radially away from the outer side surface of the outer tube 700. Since the existing release component 500 performs the release action under the action of axial traction, the transmission guide component 620 is provided to convert the axial traction force of the release component 500 into a radial driving force on the driving arm 611, so as to drive the driving arm 611 radially away from the outer side surface of the outer tube 700, and it is not necessary to change the traction direction of the existing release component 500, so as to reduce the degree of modification of the product, and thus reduce the modification cost of the product.

[0073] In this embodiment, a guide slider 621 is provided on the outer circumference of the transmission guide component 620, and a guide groove 6110 is provided on the inner side of the driving arm 611. The guide groove 6110 is constructed as a wedge-shaped groove, and the depth of the guide groove 6110 gradually decreases toward 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 toward the fulcrum. Such a design can facilitate the plug-in cooperation between the guide slider 621 and the guide groove 6110. When the transmission guide component 620 slides axially toward the fulcrum, the guide slider 621 is inserted into the guide groove 6110 and generates axial relative movement relative to the guide groove 6110 as the transmission guide component 620 continues to slide, thereby driving the driving arm 611 to be further away from the outer side of the outer tube 700, that is, as the release action stroke of the release component 500 increases, the rotation angle of the brake arm 610 also gradually increases, and the driving arm 611 is further away from the outer side of the outer tube 700 to ensure that the clamping arm 612 can be frictionally engaged with the outer surface of the inner tube 310; or after the clamping arm 612 is frictionally engaged with the outer surface of the inner tube 310, the driving arm 611 is continued to be pushed so that the clamping force of the clamping arm 612 on the inner tube 310 is greater, thereby increasing the friction damping force.

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

[0075] It can be understood that in other embodiments of the present invention, the guide groove is arranged on the outer peripheral side of the transmission guide component, and the guide slider is protruded on the inner side surface of the driving arm, the guide groove is constructed as a wedge-shaped groove, and / or the guide slider is constructed as a wedge-shaped block.

[0076] The transmission guide component 620 in this embodiment is configured as a sleeve structure corresponding to the shape of the outer side surface of the outer tube 700, and the transmission guide component 620 is sleeved on the outer tube 700 and guided by the outer tube 700 to slide axially. Such a 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 difficulty of disassembling and assembling the transmission guide component 620.

[0077] In this embodiment, the length of the driving arm 611 is greater than the length of the clamping arm 612. With such a design, the brake arm 610 can form a force-saving lever structure, so as to reduce the radial outward thrust exerted by the transmission guide component 620 on the driving arm 611 while keeping the squeezing force of the clamping arm 612 on the tubular telescopic component 300 unchanged, thereby reducing the force on the driving arm 611 and preventing the driving arm 611 from being deformed or broken due to excessive force.

[0078] like Figure 2 , Figure 8 and Fig.10As 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 in the second direction opposite to the first direction under the load force is defined as the releasing stroke, that is, 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, and the clamping surface 6120 gradually deviates from the outer surface of the tubular telescopic component 300 along the first direction. A gap 001 with a radial spacing that increases unidirectionally 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 releasing 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 (such as Fig.13 shown).

[0079] The clamping surface 6120 in this embodiment 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, so that the release speed of the tubular telescopic component 300 can be adjusted at any time as needed.

[0080] It can be understood that in other embodiments of the present invention, an elastic friction block is provided on the inner side of the clamping arm. After the clamping arm contacts the inner tube, the clamping arm exerts a greater clamping force on the inner tube by continuing to push the driving arm, so that the elastic friction block is deformed and the contact area with the inner tube is increased, thereby increasing the friction damping force.

[0081] Secondly, the brake unit 600 in this embodiment includes two brake arms 610, which are distributed on opposite sides of the tubular telescopic component 300, and the two brake arms 610 are thin plate structures that fit with the outer side of the outer tube 700 to make the overall structure more compact. By providing two brake arms 610, the frictional engagement area between the brake unit 600 and the tubular telescopic component 300 can be increased to increase the friction damping force on the tubular telescopic component 300, thereby improving the deceleration effect, and allowing the tubular telescopic component 300 to be released at a lower speed.

[0082] It can be understood that, in other embodiments of the present invention, in order to simplify the structure of the brake unit, one brake arm may be provided.

[0083] In addition, the braking unit 600 in this embodiment also includes an elastic component 630, which is an elastic sleeve mounted 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 away 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. In this way, when the actuator unit 100 drives the screw rod 200 to rotate and the tubular telescopic component 300 performs linear telescopic motion, the braking unit 600 can be prevented from applying friction damping force to the telescopic motion of the tubular telescopic component 300, thereby reducing the output power consumption of the actuator unit 100.

[0084] It can be understood that in other embodiments of the present invention, the elastic component can also be connected to an elastic rope between the two driving arms, and the elastic rope can drive the two driving arms to maintain a force state close to each other, so that the two clamping arms can maintain a force state away from each other.

[0085] It can be understood that, in other embodiments of the present invention, the elastic component may also be connected to a compression spring between the two clamping arms, and the compression spring keeps the two clamping arms in a stressed state of being away from each other.

[0086] Finally, for ease of understanding, the working process of the linear actuator in this embodiment configured as a push actuator is described as an example:

[0087] like Figure 8 and Fig.10 As shown, in normal state, the braking torsion spring 440 applies circumferential braking to the planetary carrier 413, and the planetary carrier 413 cannot rotate. At this time, the clutch 400 is in a state of maintaining the power transmission between the actuating unit 100 and the screw rod 200, and because the release component 500 does not perform a release action, the two clamping arms 612 are not in contact with the outer surface of the inner tube 310. The actuating torque of the motor is input through the sun gear 411, and then output by the ring gear 414 after being transmitted by the planetary gear 412. The ring gear 414 drives the screw rod 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 in the direction away from the actuating unit 100 by driving the tubular telescopic component 300.

[0088] like Figures 11 to 13As shown, when the brake torsion spring 440 is in a released state by operating the release component 500, the clutch 400 cuts off the power transmission between the actuating unit 100 and the screw rod 200, thereby activating the release function of the linear actuator, and the tubular telescopic component 300 is released in a direction close to the actuating unit 100 under the thrust of the load. By controlling the release action stroke of the release component 500, the clamping arm 612 can be controlled to frictionally engage 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 a friction damping force to counteract the load thrust, so that the load can be slowly released.

[0089] It can be understood that in other embodiments of the present invention, when the linear actuator is configured as a pulling actuator, the tubular telescopic component pulls the load in a direction close to the actuator unit. After the linear actuator activates the release function, the tubular telescopic component is released in a direction away from the actuator unit due to the load pulling force, and the clamping arm frictionally engages with the outer surface of the tubular telescopic component to provide a friction damping force to counteract the load pulling force.

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

[0091] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A linear actuator with safety release, comprising: an actuating unit providing an actuating torque; A lead screw driven to rotate by an actuating torque; A tubular telescopic component, which is sleeved outside the screw and driven by the rotational movement of the screw to perform linear telescopic movement; A clutch, which is used to maintain or cut off the power transmission between the actuating unit and the screw; An operable release component that drives the clutch to cut off power transmission between the actuation unit and the lead screw to activate a release function of the linear actuator; Characterized in that the linear actuator also includes: A brake unit, comprising at least one brake arm configured as a lever structure along the linear telescopic movement direction of the tubular telescopic member, the brake arm comprising a clamping arm and a driving arm located on both sides of the 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 to control the release speed of the tubular telescopic component under the load force.

2. The linear actuator with safety release as claimed in claim 1, characterized in that: The linear actuator is configured to push the actuator, and the tubular telescopic component pushes the load in a direction away from the actuator unit. After the linear actuator activates the release function, the tubular telescopic component is released in a direction close to the actuator unit due to the load thrust, and the clamping arm frictionally engages with the outer surface of the tubular telescopic component to provide a friction damping force to counteract the load thrust.

3. The linear actuator with safety release as claimed in claim 1, characterized in that: The linear actuator is configured as a pulling actuator, and the tubular telescopic component pulls the load in a direction close to the actuating unit. After the linear actuator activates the release function, the tubular telescopic component is released in a direction away from the actuating unit under the load pulling force, and the clamping arm frictionally engages with the outer surface of the tubular telescopic component to provide a friction damping force to counteract the load pulling force.

4. The linear actuator with safety release as claimed in claim 1, characterized in that: The linear actuator comprises an outer tube sleeved on the outside of a tubular telescopic component. The tubular telescopic component performs linear telescopic motion relative to the outer tube. The brake arm is pivotally connected to the outer side surface of the outer tube to form a lever structure.

5. The linear actuator with safety release as claimed in claim 4, characterized in that: The brake unit also includes a transmission guide component that slides back and forth axially along the outer tube. The release component is axially pulled to implement the release action. The transmission guide component is used to convert the axial traction 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 safety release as claimed 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 generate axial relative movement as the transmission guide component slides. The guide groove is configured as a wedge groove and / or the guide slider is configured as a wedge block.

7. The linear actuator with safety release as claimed in claim 6, characterized in that: The transmission guide component is configured as a sleeve structure corresponding to the shape of the outer side surface of the outer tube. The transmission guide component is sleeved on the outer tube and guided by the outer tube to slide axially.

8. The linear actuator with safety release as claimed in claim 7, characterized in that: The release component includes a cable and a sleeve connected to the cable. The sleeve is sleeved on an outer tube and guided by the outer tube to slide axially. The axial sliding of the sleeve comes from the traction of the cable. The transmission guide component is axially against the sleeve or forms an integral structure with the sleeve.

9. The linear actuator with safety release as claimed in claim 1, characterized in that: The linear movement of the tubular telescopic component in a first direction is defined as a working stroke, and the linear movement of the tubular telescopic component in a second direction opposite to the first direction under a load force is defined as a release stroke. The clamping arm has a clamping surface facing the outer surface of the tubular telescopic component, and the clamping surface gradually deviates from the outer surface of the tubular telescopic component along the first direction. A gap with a radial spacing that increases unidirectionally 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 linear actuator with safety release as claimed 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 action stroke of the release component increases.

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

12. The linear actuator with safety release as claimed in claim 1, characterized in that: The brake unit comprises two brake arms which are constructed into a cross lever structure along the linear telescopic movement direction of the tubular telescopic component, and the two brake arms are distributed on two opposite sides of the tubular telescopic component.

13. The linear actuator with safety release as claimed in claim 12, characterized in that: The brake unit further comprises an elastic component, which connects the two brake arms to keep the two clamping arms in a stressed state away from each other.

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