Linear actuator with quick release function

Abstract

The linear actuator with the quick release function comprises a motor, a speed reduction assembly, a lead screw and a telescopic assembly, the lead screw is driven by power transmitted by the speed reduction assembly to rotate, and the telescopic assembly is driven by the lead screw to do linear telescopic motion; the speed reduction assembly comprises a shell and a planetary speed reduction mechanism contained in the shell, the planetary speed reduction mechanism comprises a sun gear, an inner gear ring, a planetary retainer in transmission connection with the lead screw and a planetary gear rotationally installed on the planetary retainer, the lead screw penetrates through the sun gear and can rotate and freely shuttle relative to the sun gear, and the motor drives the sun gear to rotate; the brake device further comprises a brake torsion spring and a release plate slidably mounted on the outer side of the shell, the brake torsion spring tightly holds the outer side of the inner gear ring in a normal state so as to lock the inner gear ring in a rotation stopping mode, the brake torsion spring comprises a first pin connected with the release plate and a second pin fixed to the shell, and the sliding direction of the release plate is perpendicular to the axis of the lead screw. And the release plate drives the first pin to move, so that the brake torsion spring loosens the inner gear ring.

Description

TECHNICAL FIELD

[0001] The utility model relates to linear actuator technical field especially linear actuator with quick release function. BACKGROUND

[0002] Linear actuator in prior art, also called electric push rod, is widely used in furniture, medical equipment, solar power generation, emergency exit or fire alarm door and so on, its main structure includes motor, reduction assembly, screw rod and telescopic assembly, working principle is that motor drives screw rod rotation through reduction assembly, and telescopic assembly is driven by screw rod to make linear telescopic motion. UTILIT Y MODEL CONTENTS

[0003] The utility model provides a linear actuator with quick release function, can realize the quick release of screw rod to cope with the situation that motor meets failure or sudden power failure, and further improves use experience.

[0004] To solve the above technical problem, the utility model adopts the following technical scheme:

[0005] Linear actuator with quick release function, comprising:

[0006] Motor and reduction assembly, and,

[0007] Screw rod and telescopic assembly, the screw rod is driven to rotate by the power transmission of reduction assembly, and telescopic assembly is driven by screw rod to make linear telescopic motion;

[0008] The reduction assembly includes a shell and a planetary reduction mechanism housed in the shell, the planetary reduction mechanism includes a sun gear, an inner ring gear, a planetary holder in transmission connection with the screw rod, and a planetary gear rotatably installed on the planetary holder, the planetary gear is engaged between the sun gear and the inner ring gear, the screw rod penetrates the sun gear and can rotate relative to the sun gear and freely shuttle, and the motor drives the sun gear to rotate;

[0009] The linear actuator further includes a brake torsion spring and a release plate slidingly installed on the outside of the shell, the brake torsion spring is normally clamped on the outside of the inner ring gear to lock the inner ring gear, the brake torsion spring includes a first pin connected with the release plate and a second pin fixed on the shell, the sliding direction of the release plate is perpendicular to the axis of the screw rod, the release plate drives the first pin to move to release the inner ring gear from the brake torsion spring.

[0010] When the linear actuator of the present invention is in use, the braking torsion spring is normally clamped to the outer side of the inner gear ring to lock the inner gear ring against rotation. At this time, the inner gear ring is in a circumferentially locked state, that is, the inner gear ring cannot rotate. The power of the motor is input through the sun gear, and then output by the planetary retainer after being transmitted by the planetary gears, thereby driving the screw to rotate. In addition, by setting a suitable reduction ratio, the high-speed rotation of the motor can be reduced to the required low speed through the planetary reduction mechanism to meet the working requirements of the mechanical equipment. When encountering a motor failure or power outage or other situations where it is necessary to cut off the power Under the condition of force, in this embodiment, by driving the release plate to slide, the first pin can be driven to move, so that the brake torsion spring expands outward and loosens the inner ring gear, that is, the circumferential lock on the inner ring gear is released, so that the inner ring gear can rotate freely. In this case, the planetary reduction mechanism will not transmit power, and the screw rod can freely shuttle and rotate relative to the sun gear. Therefore, the screw rod can be quickly rotated by pushing and pulling the screw rod, so that the telescopic assembly can be quickly extended and retracted, realizing the quick release function; in addition, the release speed of the screw rod depends on the displacement of the release plate, so the release speed of the screw rod is controlled by controlling the displacement of the release plate.

[0011] In the aforementioned linear actuator with a quick-release function, two mounting plates are spaced circumferentially outside the housing, extending along the axis of the screw. These mounting plates are provided with retaining grooves, and the release plate's ends extend through and slidably engage the two retaining grooves. This design provides mounting locations for the release plate's sliding installation, resulting in a simple structure and easy assembly.

[0012] In the aforementioned linear actuator with a quick-release function, a locating pin is embedded in the mounting plate. The retaining groove has a notch for inserting the end of the release plate into the retaining groove. The locating pin is positioned between the notch and the release plate to prevent the end of the release plate from falling out of the retaining groove. This design facilitates quick and easy removal of the release plate.

[0013] In the aforementioned linear actuator with a quick-release function, the linear actuator further includes a release lever. The release plate is provided with a guide slot extending axially along the lead screw and arranged obliquely. The release lever is provided with a drive pin that is inserted into and slidably engaged with the guide slot. Pulling the release lever toward one axial end of the lead screw drives the release plate to move, thereby releasing the brake torsion spring from the internal gear ring. This design allows the user to drive the release plate by pulling the release lever toward one axial end of the lead screw via a traction rod or traction rope, thereby facilitating user operation.

[0014] In the above linear actuator with quick release function, the release plate is provided with a connection hole, and the first pin is inserted into the connection hole. Such a design can facilitate the connection between the first pin and the release plate, and the assembly is simple.

[0015] In the linear actuator with quick release function, the planet holder is connected with a driving coupling, the screw rod is provided with a driven coupling, the driving coupling and the driven coupling are fixed in circumferential direction and can move in axial direction when connected, allowing the screw rod to cut off the connection between the driving coupling and the driven coupling when subjected to axial load tension, the screw rod freely penetrates the planetary reduction mechanism and is provided with an elastic component at the tail, the elastic component is used to maintain the connection between the driving coupling and the driven coupling. In this way, when the motor drives the inner tube to retract and the object or human body is clamped, the screw rod drives the driven coupling to move outward to disconnect the driving coupling, cutting off the transmission of the motor output torque, the screw rod stops rotating, the inner tube stops retracting, and the anti-clamping effect is achieved; when the clamped object or human body is removed, the screw rod is reset under the action of the elastic component to reconnect the driving coupling and the driven coupling, so that the linear actuator resumes normal operation.

[0016] In the linear actuator with quick release function, the linear actuator further comprises a self-locking device connected with the screw rod, the self-locking device is used to release the brake on the screw rod when the screw rod is subjected to an actuating torque in a first direction, and to apply the brake on the screw rod when the screw rod is subjected to a load torque in a second direction. In this way, after the motor stops working, the self-locking device prevents the screw rod from rotating when subjected to a load torque in a second direction, ensuring the accuracy of the position of the load.

[0017] In the linear actuator with quick release function, the self-locking device comprises a coupling transmission unit and a friction braking unit,

[0018] The coupling transmission unit comprises an input component in transmission connection with the planet holder and an output component in transmission connection with the screw rod, the output component is provided with a self-locking angle that rotates synchronously;

[0019] The friction braking unit comprises a brake ring and a retaining ring provided with a brake block, the retaining ring surrounds the outside of the coupling transmission unit, the brake ring is fixedly surrounded on the outside of the retaining ring, the brake block rotates synchronously with the retaining ring in circumferential direction, at least one of the brake block and the self-locking angle has a gradual change surface gradually away from the axis of the screw rod in the first direction;

[0020] When the input component is subjected to an actuating torque in the first direction, the retaining ring and the output component are driven to rotate synchronously;

[0021] When the output component is subjected to a load torque in the second direction, the self-locking angle is driven to rotate in the second direction relative to the retaining ring, the brake block is extruded by the self-locking angle and moves radially outward to frictionally engage the brake ring to implement friction braking;

[0022] When the input component is driven to rotate in the second direction by the actuating torque, the retaining ring is rotated in the second direction relative to the self-locking angle, and the friction braking state is released in advance;

[0023] The first direction is opposite to the second direction. In this way, when the input component is driven to rotate in the first direction by the actuating torque, the retaining ring and the output component are driven to rotate synchronously, and the screw rod is driven to rotate, and the rotation of the screw rod can drive the load to realize linear displacement. When the actuating torque applied to the input component is stopped, the output component is driven to rotate in the second direction by the load torque, and the self-locking angle is rotated in the second direction relative to the retaining ring. At this time, the brake block is extruded by the self-locking angle and moves radially outward to be frictionally engaged with the brake ring to implement friction braking, so as to prevent the output component from continuing to rotate in the second direction, and further prevent the screw rod from rotating, thereby ensuring the accuracy of the position of the load. In addition, when the input component is driven to rotate in the second direction by the actuating torque, the retaining ring is rotated in the second direction relative to the self-locking angle, and the friction braking state is released in advance, that is, there is no frictional resistance between the brake block and the brake ring, so the power consumption of the motor can be reduced. Finally, by arranging the brake block on the retaining ring and using the brake block to move radially outward to frictionally brake the brake ring to realize the self-locking performance, compared with the torsional spring brake, not only the axial space occupied is small, but also the length of the screw rod can be reduced to reduce the machining difficulty of the screw rod, and the machining process of the brake ring and the brake block is more convenient, thereby ensuring the controllability of the performance of the brake ring and the brake block, and further realizing better self-locking controllability.

[0024] In the linear actuator with the quick release function, the self-locking device comprises a transmission sleeve, a self-locking torsional spring sleeved outside the transmission sleeve, and a self-locking sleeve sleeved outside the self-locking torsional spring and fixed relative to the inner gear ring in the circumferential direction. The planetary cage is in transmission connection with the screw rod through the transmission sleeve. When the planetary cage drives the screw rod to rotate through the transmission sleeve, the transmission sleeve drives the self-locking torsional spring to contract to move away from the self-locking sleeve. When the screw rod rotates in the second direction under the action of the load, the self-locking torsional spring is driven to expand and contact the self-locking sleeve through the transmission sleeve to brake the screw rod.

[0025] In the linear actuator with the quick release function, the speed reduction assembly further comprises a worm gear and a worm. The worm gear is connected with the sun gear and rotates synchronously. The worm is connected with the output shaft of the motor. When the worm is driven by the actuating torque in the first direction, the screw rod is driven to rotate. When the screw rod is driven by the load torque in the second direction, the screw rod is braked through the worm gear and the worm. In this way, after the motor stops working, the worm gear and the worm can prevent the screw rod from rotating when the screw rod is driven by the load torque in the second direction, thereby ensuring the accuracy of the position of the load.

[0026] These features and advantages of the present application will be disclosed in detail in the following specific embodiments and drawings.

Brief Description of the Drawings

[0027] The present invention will be further described below with reference to the accompanying drawings:

[0028] Figure 1 Schematic diagram of the structure of the linear actuator in the first embodiment of the present utility model;

[0029] Figure 2 This is an exploded schematic diagram of the linear actuator in Example 1 of the present utility model;

[0030] Figure 3 This is an exploded schematic diagram of a partial structure of a linear actuator in Example 1 of the present utility model;

[0031] Figure 4 2 is a cross-sectional view of the linear actuator in the first embodiment of the present invention;

[0032] Figure 5 for Figure 4 A partial enlarged schematic diagram;

[0033] Figure 6 This is a schematic structural diagram of the planetary reduction mechanism in Example 1 of the present utility model;

[0034] Figure 7 This is a cross-sectional view of the planetary reduction mechanism in Example 1 of the present utility model;

[0035] Figure 8 This is a schematic diagram of the structure of the brake torsion spring in the first embodiment of the present invention when it is tightly holding the inner gear ring;

[0036] Figure 9 for Figure 8 The main view;

[0037] Figure 10 This is a schematic structural diagram of the first embodiment of the present invention when the brake torsion spring releases the inner gear ring;

[0038] Figure 11 for Figure 10 The main view;

[0039] Figure 12 This is a schematic structural diagram of the input component in the first embodiment of the present utility model;

[0040] Figure 13 This is a schematic structural diagram of the output component in the first embodiment of the present utility model;

[0041] Figure 14 This is a schematic structural diagram of a retaining ring and a brake block in Example 1 of the present utility model;

[0042] Figure 15 This is a schematic diagram of the assembly of a partial structure of a linear actuator in Example 1 of the present utility model;

[0043] Figure 16 for Figure 15 The main view;

[0044] Figure 17 for Figure 16 Cross-sectional view of the middle BB;

[0045] Figure 18 for Figure 16 Cross-sectional view of CC;

[0046] Figure 19 This is a schematic diagram of a first gap formed between the input key teeth and the retaining key teeth in the first embodiment of the present invention;

[0047] Figure 20 This is a schematic diagram of a second gap formed between the output key teeth and the retaining key teeth in the first embodiment of the present invention;

[0048] Figure 21 for Figure 15 A top view of

[0049] Figure 22 for Figure 21 A partial enlarged schematic diagram of D in the middle;

[0050] Figure 23 Schematic diagram of the internal structure of the linear actuator in the second embodiment of the present invention;

[0051] Figure 24 This is a cross-sectional view of the linear actuator in the second embodiment of the present invention. Figure 1 ;

[0052] Figure 25 This is an exploded schematic diagram of the transmission sleeve in the second embodiment of the present utility model;

[0053] Figure 26 This is a schematic diagram of the assembly of the inner transmission sleeve and the outer transmission sleeve in the second embodiment of the present utility model;

[0054] Figure 27 This is a schematic diagram of the assembly of the transmission sleeve and the self-locking torsion spring in the second embodiment of the present utility model;

[0055] Figure 28 for Figure 27 Main view of the middle structure;

[0056] Figure 29 Schematic diagram of the assembly of the linear actuator part structure in the second embodiment of the present invention.

[0057] Reference numerals:

[0058] 100, motor; 200, reduction assembly; 210, planetary reduction mechanism; 211, sun gear; 212, planetary gear; 213, planetary cage; 2130, transmission groove; 214, inner ring gear; 2140, body; 2141, brake seat; 21411, support step; 230, housing; 2301, half housing; 2302, load-bearing step; 232, mounting plate; 2321, limit groove; 233, positioning pin; 240, worm gear; 250, worm; 300, Screw; 310, first bearing; 320, limit plate; 330, elastic component; 340, second bearing; 350, third bearing; 360, centripetal bearing; 400, telescopic assembly; 410, inner tube; 420, outer tube; 430, nut; 500, coupling transmission unit; 510, input component; 511, input key tooth; 512, input keyway; 513, transmission block; 520, output component; 521, self-locking angle; 5210, first gradient surface; 5211, first Limiting surface; 5212, second limiting surface; 522, output key teeth; 530, active coupling; 540, driven coupling; 600, friction brake unit; 610, brake ring; 620, retaining ring; 621, retaining key teeth; 622, first limiting angle; 623, second limiting angle; 624, guide hole; 630, brake block; 631, second gradient surface; 711, release plate; 7110, guide groove; 7111, connecting hole; 712, release rod; 7120, transmission Movable pin; 720, brake torsion spring; 721, first pin; 800, support seat; 900, limit block; 1000, transmission sleeve; 1100, outer transmission sleeve; 1110, transmission groove; 1111, first transmission surface; 1112, second transmission surface; 1120, second limit portion; 1200, inner transmission sleeve; 1210, transmission block; 1220, first limit portion; 2000, self-locking torsion spring; 2100, third pin; 2200, fourth pin; 3000, self-locking sleeve.

[0059] 001, first gap; 002, second gap; 003, third gap; 004, fourth gap. [Specific implementation method]

[0060] The utility model provides a linear actuator with a quick release function, comprising:

[0061] Motor and reduction assembly; and,

[0062] A screw and a telescopic assembly, wherein the screw is driven to rotate by the power transmitted by the reduction assembly, and the telescopic assembly is driven by the screw to perform linear telescopic motion;

[0063] The reduction assembly includes a housing and a planetary reduction mechanism housed in the housing, the planetary reduction mechanism includes a sun gear, an inner ring gear, a planetary cage connected to a screw drive, and planetary gears rotatably mounted on the planetary cage, the planetary gears meshing between the sun gear and the inner ring gear, the screw passes through the sun gear and can rotate and shuttle freely relative to the sun gear, and the motor drives the sun gear to rotate;

[0064] The linear actuator also includes a brake torsion spring and a release plate slidably mounted on the outside of the shell. Under normal circumstances, the brake torsion spring is tightly clamped to the outside of the inner ring gear to lock the inner ring gear against rotation. The brake torsion spring includes a first pin connected to the release plate and a second pin fixed to the shell. The sliding direction of the release plate is perpendicular to the axis of the screw rod. The release plate drives the first pin to move so that the brake torsion spring loosens the inner ring gear.

[0065] When the linear actuator of the present invention is in use, the brake torsion spring is normally clamped to the outer side of the inner gear ring to lock the inner gear ring against rotation. At this time, the inner gear ring is in a circumferentially locked state, that is, the inner gear ring cannot rotate. The power of the motor is input through the sun gear, and then output by the planetary retainer after being transmitted by the planetary gears, thereby driving the screw to rotate. In addition, by setting a suitable reduction ratio, the high-speed rotation of the motor can be reduced to the required low speed through the planetary reduction mechanism to meet the working requirements of the mechanical equipment. When encountering a motor failure or power outage or other situations where power needs to be cut off, In this case, in this embodiment, by driving the release plate to slide, the first pin can be driven to move, so that the brake torsion spring expands outward and loosens the inner ring gear, that is, the circumferential lock on the inner ring gear is released, so that the inner ring gear can rotate freely. In this case, the planetary reduction mechanism will not transmit power, and the screw rod can freely shuttle and rotate relative to the sun gear. Therefore, the screw rod can be quickly rotated by pushing and pulling the screw rod, so that the telescopic assembly can be quickly extended and retracted, realizing a quick release function; in addition, the release speed of the screw rod depends on the displacement of the release plate, so the release speed of the screw rod is controlled by controlling the displacement of the release plate.

[0066] 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 making creative work all fall within the scope of protection of the present invention. In addition, it should be understood that the following words indicating orientation or positional relationship such as "up", "down", "left", "right", "longitudinal", "lateral", "inside", "outside", "vertical", "horizontal", "top", "bottom", etc. are only based on the orientation or positional 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.

[0067] Example 1

[0068] like Figures 1 to 22 As shown, the linear actuator in this embodiment includes a motor 100, a reduction assembly 200, a screw rod 300 and a telescopic assembly 400. The reduction assembly 200 is transmission-connected between the motor 100 and the screw rod 300. The motor 100 drives the screw rod 300 to rotate through the reduction assembly 200. The telescopic assembly 400 is driven by the screw rod 300 to perform linear telescopic motion. The telescopic assembly 400 includes an inner tube 410, an outer tube 420 and a nut 430. The nut 430 is fixed in the inner tube 410 and is threadedly connected to the screw rod 300. The nut 430 is circumferentially and axially fixed relative to the inner tube 410. When the motor 100 drives the screw rod 300 to rotate in a first direction through the reduction assembly 200, the nut 430 drives the inner tube 410 to move to extend the telescopic assembly 400. When the screw rod 300 rotates in a second direction, the second direction is opposite to the first direction, and the nut 430 drives the inner tube 410 to move to shorten the telescopic assembly 400. Of course, when the motor 100 drives the screw rod 300 to rotate in the first direction through the reduction assembly 200, the nut 430 drives the inner tube 410 to move and the telescopic assembly 400 can also be shortened, and when the screw rod 300 is driven to rotate in the second direction, the telescopic assembly 400 extends.

[0069] like Figures 2 to 7 As shown, the reduction assembly 200 in this embodiment includes a planetary reduction mechanism 210 and a housing 230. The housing 230 is formed by connecting two half-shells 2301 and screws. The planetary reduction mechanism 210 is installed in the housing 230. The planetary reduction mechanism 210 includes a sun gear 211, planetary gears 212, a planetary retainer 213 and an inner ring gear 214. The planetary gears 212 are rotatably mounted on the planetary retainer 213. A plurality of planetary gears 212 surround the outer side of the sun gear 211 and mesh with the sun gear 211. The inner ring gear 214 Surrounding the outside of multiple planetary gears 212 and meshing with the planetary gears 212, the lead screw 300 in this embodiment includes an optical axis section and a threaded section. The optical axis section is set through the sun gear 211 and rotates with the sun gear 211 to enable the lead screw 300 to rotate and shuttle freely relative to the sun gear 211. The threaded section is threadedly connected to the nut 430. The optical axis section and the threaded section are integrally processed or the two are separately processed and then assembled and fixed. The sun gear 211 is driven to rotate by the motor 100, and the planetary retainer 213 is transmission-connected to the lead screw 300.

[0070] like Figures 2 to 11As shown, the linear actuator in this embodiment also includes a braking torsion spring 720 and a release plate 711 slidably mounted on the outside of the housing 230. The braking torsion spring 720 is normally clamped to the outside of the inner ring gear 214 to lock the inner ring gear 214 from rotation. The braking torsion spring 720 includes a first pin 721 connected to the release plate 711 and a second pin (not shown in the figure) fixed to the housing 230. The sliding direction of the release plate 711 is perpendicular to the axis of the screw rod 300, that is, the sliding path of the release plate 711 can be a straight line perpendicular to the axis of the screw rod, or an arc around the axis of the screw rod. The release plate 711 drives the first pin 721 to move so that the braking torsion spring 720 releases the inner ring gear 214.

[0071] When the linear actuator in this embodiment is used, since the braking torsion spring 720 is normally clamped to the outside of the inner ring gear 214 to lock the inner ring gear 214, the inner ring gear 214 is in a circumferentially locked state, that is, the inner ring gear 214 cannot rotate. The power of the motor 100 is input through the sun gear 211, transmitted by the planetary gear 212, and output by the planetary retainer 213, thereby driving the screw rod 300 to rotate; in addition, by setting a suitable reduction ratio, the high-speed rotation of the motor 100 can also be reduced to the required low speed through the planetary reduction mechanism 210 to meet the working requirements of the mechanical equipment; when the motor 100 fails or the power is cut off or there are other situations where the power needs to be cut off In this embodiment, by driving the release plate 711 to slide, the first pin 721 can be driven to move, so that the braking torsion spring 720 expands outward and loosens the inner ring gear 214, that is, the circumferential lock on the inner ring gear 214 is released. In this way, the inner ring gear 214 can rotate freely. In this case, the planetary reduction mechanism 210 will not transmit power. In addition, the screw rod 300 can freely shuttle and rotate relative to the sun gear 211. Therefore, by pushing and pulling the screw rod 300, the screw rod 300 can be rotated quickly, so that the telescopic assembly 400 can be quickly extended and retracted, realizing a quick release function; in addition, the release speed of the screw rod 300 depends on the displacement of the release plate 711, so the release speed of the screw rod 300 is controlled by controlling the displacement of the release plate 711.

[0072] Specifically, in order to increase the clamping force between the brake torsion spring 720 and the inner ring gear 214, the inner ring gear 214 in this embodiment includes a main body 2140 and a brake seat 2141 arranged and connected along the axial direction of the screw rod. The main body 2140 and the brake seat 2141 are connected by spline matching or integrally processed and formed so that the two cannot rotate relative to each other. The main body 2140 is engaged with the planetary gear 212, and the brake torsion spring 720 is clamped on the outside of the brake seat 2141.

[0073] like Figures 8 to 11As shown, for the convenience of the following description, in this embodiment, the direction where the telescopic component 400 is located is upward, and the direction where the corresponding deceleration component 200 is located is downward. Two mounting plates 232 are provided at intervals on the outer circumference of the shell 230. The two mounting plates 232 extend along the axis of the screw rod 300. Each mounting plate 232 is provided with a limiting groove 2321 with a closed lower end and an open upper end. The limiting groove 2321 is provided along the thickness direction of the mounting plate 232 and penetrates the mounting plate 232. The release plate 711 is located on the outer side of the shell 230, and the release plate The two ends of 711 are respectively slidably engaged with the two limiting grooves 2321, so that the release plate 711 can slide relative to the housing 230, and the two mounting plates 232 are also embedded with positioning pins 233. The limiting grooves 2321 have notches for the ends of the release plate 711 to be inserted into the limiting grooves 2321. The positioning pins 233 are located between the notches of the release plate 711 and the limiting grooves 2321 to prevent the ends of the release plate 711 from slipping out of the limiting grooves 2321. In this embodiment, the release plate 711 is a flat plate, so its sliding path is a straight line. The housing 230 is provided with a bar-shaped through hole for the first pin 721 to pass through. The release plate 711 is connected to the first pin 721. The first pin 721 has a first position and a second position. When the first pin 721 is in the first position (such as Figures 8 to 9 As shown), the brake torsion spring 720 holds the brake seat 2141 tightly, and the inner gear ring 214 is in a circumferentially locked state; when the first pin 721 is in the second position (as shown Figures 10 to 11 As shown in FIG, the brake torsion spring 720 releases the brake seat 2141, and the inner gear ring 214 can now rotate freely. By driving the release plate 711 to pull the first pin 721 toward the direction of loosening the brake torsion spring 720, that is, rotating it toward the second position, the brake torsion spring 720 releases the brake seat 2141.

[0074] To facilitate user operation, the linear actuator in this embodiment also includes a release rod 712, which extends along the axis of the screw rod 300 toward the telescopic assembly 400. The lower end of the release rod 712 is connected to the release plate 711. The release plate 711 is provided with a guide groove 7110. The guide groove 7110 is an inclined groove extending axially along the screw rod 300 and arranged obliquely. The release rod 712 is provided with a transmission pin 7120 inserted into the guide groove 7110 and slidingly engaged with the guide groove 7110. When the transmission pin 7120 engages with the lower end of the guide groove 7110, the first pin 721 is in the first position. At this time, the upper end of the guide groove 7110 extends obliquely toward the direction of the first position relative to the second position. The brake torsion spring 720 in this embodiment is left-handed, and the first position is located on the left side of the second position, and the corresponding upper end of the guide groove 7110 extends obliquely to the left. When quick release is required, the user pulls the release lever 712 upward through the traction rod or traction rope to drive the release plate 711 to move to the right, so that the first pin 721 rotates in the direction of loosening the brake torsion spring 720, thereby releasing the brake seat 2141 (such as Figures 10 to 11 ), thereby releasing the screw rod 300. The release speed of the screw rod 300 depends on the displacement of the release rod 712. After the quick release is completed, the release rod 712 is released, and the first pin 721 returns to the first position under the restoring force of the brake torsion spring 720, so that the brake torsion spring 720 re-engages the brake seat 2141 to apply circumferential braking to the inner ring gear 214.

[0075] In order to facilitate the connection between the release plate 711 and the first pin 721 , a connection hole 7111 is provided on the release plate 711 in this embodiment, and the first pin 721 is inserted into the connection hole 7111 .

[0076] It is understandable that in other embodiments of the present invention, the release rod may be omitted, and the brake torsion spring may be released from the brake seat by directly driving the release plate to move.

[0077] It can be understood that in other embodiments of the present invention, the release plate can also be slidably installed on the outside of the housing along the circumference of the brake torsion spring, and its sliding path is an arc.

[0078] It is understandable that in other embodiments of the present invention, when the spiral direction of the brake torsion spring is opposite, those skilled in the art can easily figure out how to adaptively change the tilt direction of the guide groove based on the above solution, which will not be described in detail here.

[0079] It should be noted that the circumferential braking of the inner gear ring 214 in this embodiment is released only when a quick release is required.

[0080] In addition, the linear actuator in this embodiment includes a self-locking device connected to the screw rod 300. The self-locking device is used to release the brake on the screw rod 300 when the screw rod 300 is subjected to an actuating torque in a first direction, and to brake the screw rod 300 when the screw rod 300 is subjected to a load torque in a second direction. With this design, after the motor 100 stops operating, the self-locking device prevents the screw rod 300 from rotating when subjected to a load torque in the second direction, thereby ensuring the accuracy of the load position.

[0081] like Figures 3 to 5 、 Figures 12 to 22 As shown, the self-locking device in this embodiment includes a coupling transmission unit 500 and a friction brake unit 600. The coupling transmission unit 500 includes an input component 510 and an output component 520. The input component 510 is transmission-connected to the planet holder 213. Figure 6 and Figure 12 As shown, the planetary holder 213 includes an upper bracket and a lower bracket arranged at intervals, and the planetary gear 212 is rotatably installed between the upper bracket and the lower bracket through a rotating shaft. The upper bracket is circumferentially provided with a plurality of transmission grooves 2130, and the outer peripheral side of the input component 510 is circumferentially provided with a plurality of transmission blocks 513 inserted into the transmission grooves 2130. In this way, the planetary holder 213 and the input component 510 can be relatively fixed in the circumferential direction to achieve a transmission connection between the two, and the output component 520 is transmission-connected to the screw rod 300, and the output component 520 is provided with a self-locking angle 521 that rotates synchronously.

[0082] The friction brake unit 600 includes a brake ring 610, a retaining ring 620, and a brake block 630. The brake block 630 is mounted on the retaining ring 620, which surrounds the outside of the coupling transmission unit 500. The brake ring 610 is relatively fixed around the outside of the retaining ring 620. The brake ring 610 is located inside the brake seat 2141 and the two are relatively fixed in the circumferential direction. That is, the brake ring 610 and the brake seat 2141 can be formed as a whole (equivalent to the inner gear ring 214 forming the brake ring 610) or can be splined to achieve circumferential relative fixation. When the brake ring 610 is independently formed, the brake ring 610 can be made of a wear-resistant material. The brake block 630 rotates synchronously with the retaining ring 620 in the circumferential direction. The brake block 630 and the self-locking angle 521 both have a gradient surface that gradually moves away from the axis of the screw rod 300 along the first direction.

[0083] When the input component 510 is applied with an actuating torque in a first direction, the retaining ring 620 and the output component 520 are driven to rotate synchronously;

[0084] When a load torque in the second direction is applied to the output component 520, the self-locking angle 521 is driven to rotate relative to the retaining ring 620 in the second direction. The brake block 630 is squeezed by the self-locking angle 521 and moves radially outward to frictionally engage with the brake ring 610 to implement friction braking.

[0085] When the input member 510 is rotated in the second direction by the actuating torque, the retaining ring 620 is rotated in the second direction relative to the self-locking angle 521, and the friction braking state is released in advance.

[0086] When the input member 510 is rotated in the first direction by the actuating torque, the retaining ring 620 and the output member 520 are driven to rotate synchronously, and the lead screw 300 is driven to rotate, so that the load is driven to realize linear displacement. When the actuating torque applied to the input member 510 is stopped, the output member 520 is rotated in the second direction under the action of the load torque, and the self-locking angle 521 is rotated in the second direction relative to the retaining ring 620. At this time, the brake block 630 is pressed by the self-locking angle 521 and moves radially outward, so as to be frictionally engaged with the brake ring 610 to implement friction braking, so as to prevent the output member 520 from continuing to rotate in the second direction, and further prevent the lead screw 300 from rotating, thereby ensuring the accuracy of the position of the load. In addition, when the input member 510 is applied with the actuating torque in the second direction, the retaining ring 620 is rotated in the second direction relative to the self-locking angle 521, and the friction braking state is released in advance, that is, there is no frictional resistance between the brake block 630 and the brake ring 610, so the power consumption of the motor 100 can be reduced. Finally, by arranging the brake block 630 on the retaining ring 620 and using the brake block 630 to move radially outward to frictionally brake the brake ring 610 to realize the self-locking performance, compared with the torsional spring brake, not only the axial space occupied is small, but also the length of the lead screw 300 can be reduced to reduce the processing difficulty of the lead screw 300, and the processing technology of the brake ring 610 and the brake block 630 is more convenient, thereby ensuring the controllability of the performance of the brake ring 610 and the brake block 630, and further realizing better self-locking controllability.

[0087] Specifically, as shown in Figures 12 to 14 and Figure 18 The input member 510 in the embodiment has a plurality of input key teeth 511 arranged at intervals in the circumferential direction, the input key teeth 511 protrude radially outward from the outer circumferential side of the input member 510, the output member 520 has a plurality of output key teeth 522 arranged at intervals in the circumferential direction, the output key teeth 522 protrude axially downward from the lower end surface of the output member 520, and the retaining ring 620 has a plurality of retaining key teeth 621 arranged at intervals in the circumferential direction, the retaining key teeth 621 protrude radially inward from the inner circumferential side of the retaining ring 620. The input key teeth 511, the retaining key teeth 621 and the output key teeth 522 are alternately engaged in sequence, that is, the output key teeth 522 are located between the input key teeth 511 and the retaining key teeth 621. In this way, the transmission of the input member 510, the output member 520 and the retaining ring 620 in the circumferential direction can be realized, the transmission reliability is higher, and the dimensions of the three in the radial direction are more compact after assembly.

[0088] As Figure 18 and Figure 19 As shown in Figure 18 , when the input member 510 is applied with the actuating torque in the first direction, the input member 510 rotates relative to the retaining ring 620 in the first direction to eliminate the third gap 003 until the input key teeth 511 contact the output key teeth 522 to drive the output member 520 and the retaining ring 620 to rotate synchronously, so as to move the load to the designated position, and the motor 100 stops working, at this time, the first gap 001 is formed between the input key teeth 511 and the retaining key teeth 621 (as shown in Figure 19 ). As shown in Figure 19 , the lead screw 300 will be applied with the reverse torque by the load, at this time, the output member 520 will be driven by the lead screw 300 to rotate the input key teeth 511 in the second direction synchronously through the output key teeth 522, initially, the retaining ring 620 is in a non-rotating state, and the output member 520 and the input member 510 rotate relative to the retaining ring 620 to eliminate the first gap 001 and form the second gap 002 between the output key teeth 522 and the retaining key teeth 621 (as shown in Figure 20 ), in the process of rotating the output member 520 relative to the retaining ring 620 in the second direction to eliminate the first gap 001, the self-locking angle 521 will apply a radial outward extrusion force to the brake block 630 to make the brake block 630 move radially outward to be frictionally engaged with the brake ring 610 to implement the friction braking, thereby preventing the lead screw 300 from continuing to rotate and ensuring the accuracy of the position of the load. As shown in Figure 20 , when the motor 100 applies the actuating torque in the second direction to the input member 510, initially, the output member 520 is in a non-rotating state, at this time, the input key teeth 511 drive the retaining ring 620 to rotate relative to the output member 520, thereby eliminating the second gap 002 and forming the third gap 003 between the output key teeth 522 and the input key teeth 511 (as shown in Figure 18 ), in the process of rotating the retaining ring 620 to drive the brake block 630 relative to the output member 520 in the second direction, the brake block 630 will move radially inward to reset to fail to be frictionally engaged with the brake ring 610, thereby releasing the friction braking state in advance, when the retaining key teeth 621 contact the output key teeth 522 to drive the output member 520 to rotate synchronously in the second direction to drive the lead screw 300 to rotate in the second direction, in this process, since there is no friction resistance between the brake block 630 and the brake ring 610, the power consumption of the motor 100 can be reduced.

[0089] In this embodiment, input key slots 512 with bottom surfaces are formed between adjacent input key teeth 511. Retaining key teeth 621 are located in input key slots 512 and axially restrained by the bottom surface and output component 520. This design axially restrains retaining key teeth 621 via the bottom surface and output component 520, thereby indirectly restraining retaining ring 620. This eliminates the need for additional axial restraint of retaining ring 620, thereby simplifying the structure of the self-locking device.

[0090] Preferably, the retaining ring 620 overlaps with the projection of the input component 510 in the axial direction, and the retaining ring 620 overlaps with the projection of the output component 520 in the axial direction, and the axial direction is parallel to the axial direction of the screw rod 300. Such a design can further reduce the axial dimension of the self-locking device to reduce the axial space occupied by the self-locking device and shorten the length of the screw rod 300.

[0091] like Figures 13 to 15 ,as well as Figures 21 to 22 As shown, in this embodiment, the portion of the output component 520 surrounded by the retaining ring 620 has a circumferential surface, the self-locking angle 521 radially protrudes from the circumferential surface and has a first gradual surface 5210 facing the brake block 630, and the brake block 630 has a second gradual surface 631 facing the first gradual surface. Both the first gradual surface 5210 and the second gradual surface 631 gradually move away from the axis of the screw rod 300 along the first direction. Figures 21 to 22 As shown, when the output component 520 is applied with a load torque in the second direction, the self-locking angle 521 will be driven to rotate in the second direction relative to the retaining ring 620. At this time, the first gradient surface 5210 will gradually push the second gradient surface 631 to move radially outward. Through the cooperation of the first gradient surface 5210 and the second gradient surface 631, the brake block 630 can be pushed radially outward as a whole to increase the contact area between the brake block 630 and the brake ring 610, thereby increasing the friction braking force.

[0092] Preferably, the self-locking angle 521 and the output component 520 form an integral structure. This design can not only save the assembly process of the self-locking angle 521 and the output component 520, thereby reducing the assembly steps, but also improve the connection reliability and rotation synchronization of the self-locking angle 521 and the output component 520.

[0093] In this embodiment, the first gradient surface 5210 extends in a spiral or straight manner from one end close to the axis of the screw rod 300 to the end away from the axis of the screw rod 300; the second gradient surface 631 extends in a spiral or straight manner from one end close to the axis of the screw rod 300 to the end away from the axis of the screw rod 300. The first gradient surface 5210 is adapted to the second gradient surface 631, that is, when the first gradient surface 5210 extends in a spiral, the second gradient surface 631 also extends in a spiral. When the first gradient surface 5210 extends straight, the second gradient surface 631 extends straight. Such a design can make the process of the brake block 630 being squeezed by the self-locking angle 521 and moving radially outward more stable.

[0094] In this embodiment, the first gradient surface 5210 and the second gradient surface 631 both extend in a spiral manner, wherein the central angle of the first gradient surface 5210 relative to the axis of the screw rod 300 is smaller than the central angle of the second gradient surface 631 relative to the axis of the screw rod 300. When the output component 520 and the retaining ring 620 are in relative rotation, the first gradient surface 5210 is always located within the circumferential range of the second gradient surface 631. This is because: when the central angle of the first gradient surface 5210 relative to the axis of the screw rod 300 is greater than the central angle of the second gradient surface 631 relative to the axis of the screw rod 300, part of the first gradient surface 5210 will abut against the inner side surface of the retaining ring 620. When the brake block 630 is squeezed by the self-locking angle 521, the first gradient surface 5210 will radially squeeze the inner side surface of the retaining ring 620 outward during the process of rotating in the second direction, causing the retaining ring 620 to rupture. The present technical solution avoids the contact between the first gradient surface 5210 and the inner side surface of the retaining ring 620, thereby avoiding the rupture of the retaining ring 620.

[0095] To ensure that the first gradually changing surface 5210 is always within the circumferential range of the second gradually changing surface 631, in this embodiment, a first limiting surface 5211 and a second limiting surface 5212 are formed at the circumferential ends of the self-locking angle 521, respectively. A first limiting angle 622 and a second limiting angle 623 are circumferentially spaced apart on the inner surface of the retaining ring 620. The first limiting angle 622 is located in the radial direction of one end of the brake block 630 and forms a circumferential interference with the first limiting surface 5211. The second limiting angle 623 is located in the radial direction of the other end of the brake block 630 and forms a circumferential interference with the second limiting surface 5212. With this design, the first limiting angle 622 and the second limiting angle 623 can limit the rotation angle of the self-locking angle 521, ensuring that during the relative rotation of the output component 520 and the retaining ring 620, the first gradually changing surface 5210 is always within the circumferential range of the second gradually changing surface 631.

[0096] In order to form the above-mentioned first limit angle 622 and second limit angle 623, the retaining ring 620 in this embodiment is provided with a guide hole 624 adapted to the brake block 630. The guide hole 624 extends from the inner ring surface of the retaining ring 620 to the outer ring surface, and the brake block 630 is embedded in the guide hole 624 so that the brake block 630 and the retaining ring 620 maintain circumferential synchronous rotation and can move radially relative to each other. The above-mentioned first limit angle 622 is formed between one axial side wall of the guide hole 624 and the inner ring surface of the retaining ring 620, and the above-mentioned second limit angle 623 is formed between the other axial side wall and the inner ring surface of the retaining ring 620. By designing the guide hole 624, the brake block 630 can be moved radially and the circumferential synchronous rotation of the brake block 630 and the retaining ring 620 can be achieved. The structure is relatively simple and the assembly is relatively convenient. The brake block 630 can also be independently processed and formed to facilitate the subsequent separate replacement of the brake block 630, thereby reducing maintenance costs.

[0097] like Figure 5 As shown, in order to achieve axial limitation of the brake block 630, a limit block 900 is further provided on one side of the brake block 630 in this embodiment. The limit block 900 cooperates with the bottom wall of the guide hole 624 to axially limit the brake block 630, wherein there is a gap between the limit block 900 and the brake block 630 to avoid contact between the two, thereby facilitating the radial movement of the brake block 630.

[0098] It will be appreciated that in other embodiments of the present invention, the brake pad and retaining ring form an integral structure, and the brake pad can be elastically deformed by being squeezed by the gradient surface. This design allows the output component to be made of an elastic material. When a portion of the output component is squeezed by the self-locking angle, it will elastically deform radially outward, thereby achieving friction braking with the brake ring.

[0099] It is understandable that in other embodiments of the present invention, the self-locking angle is provided with a first gradual surface, while the brake block is not provided with a second gradual surface; or, the brake block is provided with a second gradual surface, while the self-locking angle is not provided with a first gradual surface.

[0100] In addition, if Figures 1 to 5 As shown, the reduction assembly 200 in this embodiment also includes a worm gear 240 and a worm 250, and the sun gear 211 includes an engaging section provided with teeth and a connecting section extending axially downward. The connecting section of the worm gear 240 and the sun gear 211 is connected by a spline connection or an interference fit so that the worm gear 240 and the sun gear 211 can rotate synchronously. The worm 250 is connected to the output shaft of the motor 100, so that the power of the motor 100 is transmitted to the sun gear 211 after being reduced by the worm gear, which further reduces the output speed of the inner ring gear 214 and improves the output torque of the reduction assembly 200, that is, increases the reduction ratio of the reduction assembly 200, which can further meet the use requirements of large thrust output.

[0101] It can be understood that in other embodiments of the utility model, the self-locking device can also be omitted, and the screw rod can also be braked through the worm self-locking.

[0102] In order to facilitate understanding, the working process of the linear actuator in the embodiment is described:

[0103] In normal state, the brake torsional spring 720 implements rotation locking to the brake seat 2141, at this time the inner gear ring 214 is locked and cannot rotate, the motor 100 can drive the screw rod 300 to rotate in the first direction through the planetary holder 213, the input component 510 and the output component 520 in the planetary reduction mechanism 210, so as to move the load to the specified position. Under the action of the load torque, the excessive rotation of the screw rod 300 in the second direction is limited through the friction braking of the brake block 630 and the brake ring 610, thereby preventing the load from being displaced greatly after the motor 100 stops working.

[0104] When the screw rod 300 is quickly released, the brake torsional spring 720 is loosened through the operation of the release pull rod 712, so as to release the circumferential braking to the brake seat 2141, at this time the inner gear ring 214 can rotate freely, then the screw rod 300 is driven to rotate in the second direction, although the rotation of the screw rod 300 drives the brake block 630 to contact the brake ring 610 to implement the friction braking, but the cooperation of the brake ring 610 and the brake seat 2141 can also realize the free rotation, so that the self-locking between the brake block 630 and the brake ring 610 is invalid, thereby the screw rod 300 can rotate quickly in the second direction, and the quick release function is realized.

[0105] Secondly, as Figure 3 , Figure 5 and Figure 13As shown, the planetary retainer 213 in this embodiment is connected to a driving coupling 530. In this embodiment, the driving coupling 530 is provided on the output component 520, and a driven coupling 540 is provided on the screw rod 300. The driving coupling 530 and the driven coupling 540 remain relatively fixed in the circumferential direction when connected and can move relative to each other axially, that is, the driving coupling 530 and the driven coupling 540 are both ratchets or the two are splined to allow the screw rod 300 to cut off the connection between the driving coupling 530 and the driven coupling 540 when subjected to axial load tension. Since the screw rod 300 in this embodiment can freely pass through the self-locking device and the planetary reduction mechanism 210, that is, the screw rod 300 can move axially relative to the planetary reduction mechanism 210, the input component 510 and the output component 520. An elastic component 330 is set at the tail of the screw rod 300, and the elastic component 330 is a spring. A first bearing 310 is also provided between the tail of the screw rod 300 and the sun gear 211. The lower end of the screw rod 300 is provided with a limit plate 320 fixed by a screw. The lower end of the elastic component 330 is connected to the limit plate 320, and the upper end of the elastic component 330 is connected to the first bearing 310. The elastic component 330 applies an elastic force toward its tail to the screw rod 300 to maintain the connection trend of the active coupling 530 and the driven coupling 540.

[0106] Taking the linear actuator as an example, when the motor 100 drives the inner tube 410 in the telescopic assembly 400 and the inner tube 410 is pinched by an object or a person during retraction, the inner tube 410 cannot retract under the drive of the nut 430, so the screw 300 is pulled upward. At this time, the driven coupling 540 on the screw 300 can disengage from the driving coupling 530, cutting off the transmission of the actuating torque. The screw 300 stops rotating, the nut 430 stops moving, and the inner tube 410 stops retracting, achieving an anti-pinch effect. When the screw 300 is pulled upward, the elastic component 330 is compressed. Therefore, when the pinched object or person is removed, the elastic component 330 has a restoring force after compression, which can pull the screw 300 back, thereby reconnecting the driving coupling 530 and the driven coupling 540 on the screw 300, and the linear actuator resumes normal operation.

[0107] It can be understood that in other embodiments of the present invention, the output component and the screw rod are matched through splines, that is, the internal splines of the output component form the active coupling, and the external splines on the screw rod form the driven coupling. Such a design can also achieve a state in which the active coupling and the driven coupling remain relatively fixed in the circumferential direction and can move axially relative to each other when connected.

[0108] Finally, if Figure 5As shown, since the lead screw 300 in the embodiment freely penetrates through the self-locking device and the planetary reduction mechanism 210, a support seat 800 is sleeved on the lead screw 300, the support seat 800 is used to bear the axial load transmitted by the lead screw 300, the axial load will apply an axial force to the tail direction of the lead screw, the brake seat 2141 is provided with a support step 21411 higher than the top surface of the brake block 630, the limiting block 900 is supported on the support step 21411 and has a gap with the top surface of the brake block 630, the top of the brake seat 2141 is further provided with a limiting step, the second bearing 340 is located on the limiting step and supported on the top of the limiting block 900, the support seat 800 is supported on the second bearing 340, and the second bearing 340 is a thrust bearing capable of bearing an axial force; in addition, the outer side of the body 2140 and the shell 230 are further provided with a radial bearing 360 and a third bearing 350, the radial bearing 360 supports and centers the body 2140, and the inner side of the shell 230 is further provided with a bearing step 2302, the bearing step 2302 is used to support the third bearing 350, and the third bearing 350 is a thrust bearing, which is used to axially support the radial bearing 360 and can bear an axial force, when the load applies an axial force to the tail direction of the lead screw 300, the axial force will be applied to the support seat 800, and the axial load is transmitted to the brake seat 2141, the body 2140 and the third bearing 350, and finally the bearing step 2302 bears the axial load thrust guided by the inner ring gear 214, avoiding the axial load thrust of the lead screw 300 affecting the planetary retainer 213, the planetary gear 212 and the sun gear 211. In the prior art, a bearing is arranged at the tail of the lead screw to bear the axial load thrust of the lead screw, such a design makes the length of the lead screw longer, thereby increasing the machining difficulty and the poor concentricity during work, and the technical scheme changes the transmission path of the axial load thrust, so that the bearing at the tail can be omitted to shorten the length of the lead screw, thereby improving the machining convenience of the lead screw and the concentricity during work.

[0109] Embodiment two

[0110] As Figures 23 to 29As shown, the self-locking device in this embodiment includes a transmission sleeve 1000, a self-locking torsion spring 2000 sleeved on the outside of the transmission sleeve 1000, and a self-locking sleeve 3000 sleeved on the outside of the self-locking torsion spring 2000. The inner gear ring 214 is located on the outside of the self-locking sleeve 3000 and the two are relatively fixed in the circumferential direction. For example, one of the outer circumferential side of the self-locking sleeve 3000 and the inner circumferential side of the inner gear ring 214 is provided with a plurality of first positioning protrusions extending along its axial direction, and the other is provided with a first positioning groove for inserting the first positioning protrusion. The self-locking sleeve 3000 and the inner gear ring 214 are relatively fixed in the circumferential direction by plugging and fitting the first positioning protrusion and the first positioning groove. The planet holder 213 is connected to the screw rod 300 through the transmission sleeve 1000. When the planet holder 213 drives the screw rod 300 to rotate through the transmission sleeve 1000, the transmission sleeve 1000 drives the self-locking torsion spring 2000 to contract and move away from the self-locking sleeve 3000. In this way, the self-locking torsion spring 2000 can rotate smoothly relative to the self-locking sleeve 3000. Therefore, when the power of the motor 100 is used as a power source to drive the screw rod 300 to rotate in the first direction and the second direction, there is no friction resistance between the self-locking torsion spring 2000 and the self-locking sleeve 3000, thereby reducing the power consumption of the motor 100. When the screw rod 300 reverses under the action of load, since the inner ring gear 214 and the self-locking sleeve 3000 are circumferentially locked, the self-locking torsion spring 2000 is driven outward through the transmission sleeve 1000 to contact the self-locking sleeve 3000, so that friction resistance can be generated between the self-locking torsion spring 2000 and the self-locking sleeve 3000. The friction resistance can prevent the self-locking torsion spring 2000 from rotating relative to the self-locking sleeve 3000, and further prevent the transmission sleeve 1000 from rotating, thereby achieving braking of the screw rod 300, thereby preventing the screw rod 300 from reversing under the action of load and causing the load to drop, thereby avoiding the occurrence of safety accidents.

[0111] It is understandable that in other embodiments of the present invention, the inner gear ring may also form a self-locking sleeve, that is, the inner gear ring and the self-locking sleeve are integrally formed.

[0112] Since the self-locking torsion spring 2000 will contact the self-locking sleeve 3000 after expanding outward, and friction resistance will be generated between the self-locking torsion spring 2000 and the self-locking sleeve 3000, in order to extend the service life of the self-locking sleeve 3000, the self-locking sleeve 3000 in this embodiment is independently processed and formed and is made of wear-resistant material.

[0113] The transmission sleeve 1000 in this embodiment includes an outer transmission sleeve 1100 and an inner transmission sleeve 1200, wherein the outer transmission sleeve 1100 and the planetary retainer 213 are relatively fixed in the circumferential direction by spline cooperation, and the inner transmission sleeve 1200 is circumferentially fixed relative to the screw rod 300, that is, the inner transmission sleeve 1200 and the screw rod 300 are circumferentially fixed by spline connection.

[0114] It is understandable that in other embodiments of the present invention, the outer transmission sleeve and the planetary cage may be integrally formed; or the inner transmission sleeve and the screw rod may be integrally formed.

[0115] When the outer transmission sleeve 1100 in this embodiment drives the screw rod 300 to rotate forward through the inner transmission sleeve 1200, the outer transmission sleeve 1100 drives the self-locking torsion spring 2000 to contract. At this time, the transmission sleeve 1000 will not be subjected to the friction resistance applied by the self-locking sleeve 3000, thereby reducing the power consumption of the motor 100; and when the screw rod 300 is reversed under the action of the load and drives the inner transmission sleeve 1200 to rotate, the inner transmission sleeve 1200 drives the self-locking torsion spring 2000 to expand outward, thereby achieving braking of the screw rod 300, and when the motor 100 needs to drive the screw rod 300 to reverse, the inner gear ring 214 is clamped by the braking torsion spring 720 and is circumferentially braked, thereby enabling the outer transmission sleeve 1100 to drive the screw rod 300 through the inner transmission sleeve 1200. 00 reverses. During this process, the outer transmission sleeve 1100 has an idling stroke relative to the inner transmission sleeve 1200 and a working stroke for driving the inner transmission sleeve 1200 to rotate. When the outer transmission sleeve 1100 is in the idling stroke, the outer transmission sleeve 1100 drives the self-locking torsion spring 2000 to contract. In this way, when the motor 100 drives the screw rod 300 to reverse, the self-locking torsion spring 2000 can be first contracted away from the self-locking sleeve 3000 to avoid contact between the two and generate friction resistance, that is, the self-locking of the self-locking torsion spring 2000 is released, and then the inner transmission sleeve 1200 is driven to rotate to make the screw rod 300 reverse and drive the load to descend. Therefore, the friction resistance applied by the self-locking sleeve 3000 will not be applied during the entire descent process, thereby reducing the power consumption of the motor 100.

[0116] The outer transmission sleeve 1100 includes a plurality of arc blocks that are arranged around the axis of the screw rod 300 and are circumferentially spaced, and a transmission groove 1110 is formed between two adjacent arc blocks, so that the outer transmission sleeve 1100 has a plurality of transmission grooves 1110, and the inner transmission sleeve 1200 is provided with a transmission block 1210 that extends radially outward and is inserted into the transmission groove 1110, and the arc length of the transmission block 1210 is less than the arc length of the transmission groove 1110, and the transmission groove 1110 has a first transmission surface 1111 and a second transmission surface 1112, that is, the two circumferentially opposite side surfaces of the two adjacent arc blocks respectively form the above-mentioned first transmission surface 1111 and the second transmission surface 1112, when the telescopic assembly 400 is in the shortest state, the first transmission surface 1111 and the transmission block 1210 are offset, and a fourth gap 004 is formed between the second transmission surface 1112 and the transmission block 1210, and the screw rod 300 rotates toward the first direction to the first transmission surface 111 1 is located in the same transmission groove 1110 The second transmission surface 1112 rotates in the same direction, so that the outer transmission sleeve 1100 drives the screw rod 300 to rotate in the first direction through the inner transmission sleeve 1200 and the screw rod 300 drives the inner transmission sleeve 1200 to rotate in the second direction under the action of the load, the transmission block 1210 and the first transmission surface 1111 are always kept in contact with each other, and when the outer transmission sleeve 1100 drives the screw rod 300 to rotate in the second direction through the inner transmission sleeve 1200, due to the fourth gap 004 between the second transmission surface 1112 and the transmission block 1210, before the second transmission surface 1112 is not contacted with the transmission block 1210, the outer transmission sleeve 1100 is in an idling stroke of idling relative to the inner transmission sleeve 1200, and when the second transmission surface 1112 is contacted with the transmission block 1210, the outer transmission sleeve 1100 is in a working stroke of driving the inner transmission sleeve 1200 to rotate.

[0117] like Figure 27 、 Figure 28 and Figure 29As shown, the spiral direction of the self-locking torsion spring 2000 in this embodiment is the same as the first direction, and it includes a third pin 2100 at the lower end and a fourth pin 2200 at the upper end. The third pin 2100 is inserted into the transmission groove 1110 and is located outside the fourth gap 004, that is, the third pin 2100 is located between two adjacent arc blocks and below the transmission block 1210. The axial projection of the third pin 2100 is located within the axial projection of the fourth gap 004. The second transmission surface 1112 is provided with a notch, and the fourth pin 2200 is located in the notch. The fourth pin 2200 is clamped on the side of the transmission block 1210 away from the fourth gap 004 and the transmission Between the side walls of the movable groove, in this way, when the screw rod 300 rotates in the first direction, the first transmission surface 1111 on the outer transmission sleeve 1100 drives the fourth pin 2200 to rotate so that the self-locking torsion spring 2000 contracts. When the screw rod 300 rotates in the second direction under the action of the load, the transmission block 1210 on the inner transmission sleeve 1200 drives the fourth pin 2200 to reverse so that the self-locking torsion spring 2000 expands outward and contacts the self-locking sleeve 3000. When the motor 100 drives the screw rod 300 to reverse, the outer transmission sleeve 1100 drives the third pin 2100 to reverse through the second transmission surface 1112 when it is in the idling stroke to contract the self-locking torsion spring 2000.

[0118] It is understandable that in other embodiments of the present invention, the spiral direction of the self-locking torsion spring can also be the same as the second direction, and the fixing method of the corresponding third pin and the fourth pin can be adaptively changed, which will not be described in detail here.

[0119] In order to achieve axial limitation of the self-locking torsion spring 2000, the outer transmission sleeve 1100 in this embodiment further includes an annular second limiting portion 1120, with an arc-shaped block integrally formed on the top surface of the second limiting portion 1120. The inner transmission sleeve 1200 is provided with a first limiting portion 1220, i.e., the top of at least one of the transmission blocks 1210 extends radially outward to form the above-mentioned first limiting portion 1220. The self-locking torsion spring 2000 is axially limited between the first limiting portion 1220 and the second limiting portion 1120. Preferably, one side of the first limiting portion 1220 abuts against the fourth pin 2200 to increase the contact area between the fourth pin 2200 and the transmission block 1210, thereby increasing the installation reliability of the fourth pin 2200.

[0120] For ease of understanding, the working process of the linear actuator in this embodiment is described as follows:

[0121] In normal operation, the braking torsion spring 720 applies a circumferential brake to the inner ring gear 214, locking the inner ring gear 214 from rotating. The motor 100, via the planetary retainer 213 in the planetary reduction mechanism 210, drives the screw 300 in the first direction to move the load to a desired position. Under the load torque, the friction between the self-locking torsion spring 2000 and the self-locking sleeve 3000 limits excessive rotation of the screw 300 in the second direction, thereby preventing significant displacement of the load after the motor 100 stops operating.

[0122] When the screw rod 300 is quickly released, the brake torsion spring 720 can be operated to loosen the brake seat 2141 by operating the release rod 712 to release the circumferential braking of the inner ring gear 214. At this time, the inner ring gear 214 can rotate freely, and then the screw rod 300 is driven to rotate it in the second direction. Although the rotation of the screw rod 300 will drive the self-locking torsion spring 2000 to expand outward and contact the self-locking sleeve 3000, the cooperation between the self-locking sleeve 3000 and the inner ring gear 214 can also achieve free rotation. Therefore, the self-locking between the self-locking torsion spring 2000 and the self-locking sleeve 3000 can be invalidated, thereby allowing the screw rod 300 to rotate quickly in the second direction, thereby realizing the quick release function.

[0123] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art will understand that the present invention includes, but is not limited to, the drawings and the contents described in the above specific embodiments. Any modifications that do not deviate from the functional and structural principles of the present invention are intended to be included within the scope of the claims.

Claims

1. A linear actuator with quick release function, comprising: Motor and reduction assembly; as well as, A screw and a telescopic assembly, wherein the screw is driven to rotate by the power transmitted by the reduction assembly, and the telescopic assembly is driven by the screw to perform linear telescopic motion; The reduction assembly comprises a housing and a planetary reduction mechanism housed in the housing, the planetary reduction mechanism comprising a sun gear, an inner ring gear, a planetary cage connected to a screw drive, and planetary gears rotatably mounted on the planetary cage, the planetary gears meshing between the sun gear and the inner ring gear, the screw passes through the sun gear and can rotate and shuttle freely relative to the sun gear, and the motor drives the sun gear to rotate; The linear actuator also includes a brake torsion spring and a release plate slidably mounted on the outside of the shell. Under normal circumstances, the brake torsion spring is tightly clamped to the outside of the inner ring gear to lock the inner ring gear against rotation. The brake torsion spring includes a first pin connected to the release plate and a second pin fixed to the first shell. The sliding direction of the release plate is perpendicular to the axis of the screw rod. The release plate drives the first pin to move so that the brake torsion spring loosens the inner ring gear.

2. The linear actuator with a quick release function as described in claim 1, wherein two mounting plates extending along the axis of the screw are provided at circumferential intervals on the outer side of the shell, and the mounting plates are provided with limiting grooves, and the two ends of the release plate respectively pass through the two limiting grooves and slide in conjunction with the limiting grooves.

3. The linear actuator with quick release function according to claim 2, characterized in that: A positioning pin is embedded in the mounting plate, and the limiting groove has a notch for the end of the release plate to be inserted into the limiting groove. The positioning pin is arranged between the notch and the release plate to prevent the end of the release plate from escaping from the limiting groove.

4. The linear actuator with quick release function according to claim 1, wherein: The linear actuator also includes a release rod, the release plate is provided with a guide groove extending along the axial direction of the screw and arranged obliquely, the release rod is provided with a transmission pin inserted into the guide groove and slidingly engaged with the guide groove, and the release rod is pulled toward one axial end of the screw to drive the release plate to move so that the brake torsion spring loosens the inner gear ring.

5. The linear actuator with quick release function according to claim 1, wherein: The release plate is provided with a connection hole, and the first pin is inserted into the connection hole.

6. The linear actuator with quick release function according to claim 1, wherein: The planetary retainer is connected to a driving coupling, and a driven coupling is provided on the screw rod. When the driving coupling and the driven coupling are connected, they remain relatively fixed in the circumferential direction and can move relative to each other in the axial direction, allowing the screw rod to cut off the connection between the driving coupling and the driven coupling when subjected to axial load tension. The screw rod freely passes through the planetary reduction mechanism and an elastic component is provided at the tail end. The elastic component is used to maintain the connection trend of the driving coupling and the driven coupling.

7. The linear actuator with quick release function according to any one of claims 1 to 6, characterized in that: The linear actuator further comprises a self-locking device connected to the screw rod, wherein the self-locking device is used to release the brake on the screw rod when the screw rod is subjected to an actuating torque in a first direction, and to brake the screw rod when the screw rod is subjected to a load torque in a second direction.

8. The linear actuator with quick release function according to claim 7, wherein: The self-locking device includes a coupling transmission unit and a friction brake unit. The coupling transmission unit includes an input component connected to the planetary cage and an output component connected to the screw, and the output component is provided with a self-locking angle that rotates synchronously; The friction brake unit includes a brake ring and a retaining ring with a brake block installed, the retaining ring surrounds the outer side of the coupling transmission unit, the brake ring relatively fixedly surrounds the outer side of the retaining ring, the brake block rotates synchronously with the retaining ring in the circumferential direction, and at least one of the brake block and the self-locking angle has a gradient surface gradually away from the axis of the screw rod along the first direction; When an actuating torque in a first direction is applied to the input component, the retaining ring and the output component are driven to rotate synchronously; when a load torque in a second direction is applied to the output component, the self-locking angle is driven to rotate relative to the retaining ring in the second direction, and the brake block is squeezed by the self-locking angle and moves radially outward to frictionally engage with the brake ring to implement friction braking; When the input component is applied with an actuating torque in a second direction, the retaining ring is driven to rotate in the second direction relative to the self-locking angle, thereby releasing the friction braking state in advance; The first direction is opposite to the second direction.

9. The linear actuator with quick release function according to claim 7, wherein: The self-locking device includes a transmission sleeve, a self-locking torsion spring sleeved on the outside of the transmission sleeve, and a self-locking sleeve sleeved on the outside of the self-locking torsion spring and fixed circumferentially relative to the inner gear ring. The planetary retainer is connected to the screw rod through the transmission sleeve. When the planetary retainer drives the screw rod to rotate through the transmission sleeve, the transmission sleeve drives the self-locking torsion spring to contract and move away from the self-locking sleeve. When the screw rod rotates in the second direction under the action of the load, the self-locking torsion spring is driven outward by the transmission sleeve to contact the self-locking sleeve to brake the screw rod.

10. The linear actuator with quick release function according to any one of claims 1 to 6, characterized in that: The reduction assembly also includes a worm gear and a worm. The worm gear is connected to the sun gear and rotates synchronously. The worm gear is connected to the output shaft of the motor. When an actuating torque in a first direction is applied to the worm gear, the worm gear drives the lead screw to rotate. When a load torque in a second direction is applied to the lead screw, the lead screw is braked by self-locking the worm gear.

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