A linear actuator with smooth clutch

Abstract

The present invention discloses a linear actuator with smooth clutch engagement, belonging to the technical field of linear transmission. It includes a housing, a driving worm gear, a rotating lead screw, and a driving nut. The driving worm gear drives the rotating lead screw to rotate, and the rotation of the rotating lead screw drives the driving nut to move axially along the rotating lead screw. A clutch device is provided between the driving worm gear and the rotating lead screw. The clutch device includes a coupling tooth sleeve that can move axially relative to the rotating worm gear. An axially limiting kit is sleeved outside the rotating lead screw, and the axially limiting kit abuts against the housing axially. The axially limiting kit and the rotating lead screw are positioned axially. When the rotating lead screw is subjected to an axial load, the rotating lead screw transmits the axial force to the housing through the axially limiting kit, and no axial force is transmitted axially between the coupling tooth sleeve and the axially limiting kit. The advantage of the present invention is that the smoothness of the clutch device is better when it is driven.

Description

Technical Field

[0001] The invention relates to a linear actuator with smooth clutch, belonging to the technical field of linear transmission. Background Art

[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 a drive motor, a transmission worm, a worm wheel, a lead screw and a nut. The working principle is that the drive motor drives the transmission worm to rotate, the transmission worm engages with the worm wheel to drive the worm wheel to rotate, the rotation of the worm wheel drives the lead screw to rotate, and the rotation of the lead screw drives the nut to move axially. The nut is generally connected to an inner tube to achieve the telescopic movement of the inner tube.

[0003] In combination with the application environment of the linear actuator, when the linear actuator encounters a drive motor failure, or a power outage or other situation where power needs to be cut off, a clutch device will be added. The clutch device is mainly used to cut off the power between the drive motor and the rotating screw, so that reverse push can be achieved by manually driving the rotating screw to rotate.

[0004] For the clutch device, most of them realize the engine docking by moving one of the two parts axially. If one of the two parts is subjected to axial force, it will inevitably affect the difficulty of moving, resulting in the clutch device being not smooth, the operating experience is not good, and even the clutch device may be damaged. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a linear actuator with smooth clutching, so that the clutch device has better smoothness when being driven.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A linear actuator with smooth clutch comprises a housing, a transmission worm gear, a rotating screw and a transmission nut, wherein the transmission worm gear drives the rotating screw to rotate, and the rotation of the rotating screw drives the transmission nut to move axially along the rotating screw, a clutch device is arranged between the transmission worm gear and the rotating screw, the clutch device comprises a coupling gear sleeve which can move axially relative to the rotating worm gear, an axial limiting kit is arranged on the outer sleeve of the rotating screw, the axial limiting kit is axially abutted against the housing, the axial limiting kit and the rotating screw are kept positioned in the axial direction, when the rotating screw is subjected to an axial load, the rotating screw transmits the axial force to the housing through the axial limiting kit, and no axial force is transmitted between the coupling gear sleeve and the axial limiting kit in the axial direction.

[0008] The beneficial effects of the present invention are as follows:

[0009] In the linear actuator of the present invention, a clutch device is provided. The clutch device is mainly achieved by the axial movement of the driving coupling gear sleeve. Therefore, for the coupling gear sleeve, when it is stressed, it is optimal to only receive the force from the driving member, and to avoid or reduce the axial force from other components as much as possible. In the entire linear actuator, the axial force of other components mainly comes from the rotating lead screw. The rotating lead screw pushes the target to be pushed through the transmission nut, and the target to be pushed will naturally react the bearing capacity back to the rotating lead screw. If the rotating lead screw transfers the axial force to the coupling gear sleeve of the clutch device, it will increase the resistance when the user needs to move the coupling gear sleeve, and it is easy to damage the clutch device after long-term use.

[0010] Therefore, in this embodiment, an axial limiting kit is sleeved outside the rotating lead screw. The axial limiting kit itself is axially limited to the rotating lead screw. Secondly, the axial limiting kit is also axially limited to the housing. In this installation method, the axial force on the rotating lead screw can be transferred to the housing through the axial limiting kit, and no axial force is transferred between the coupling gear sleeve and the axial limiting kit. Therefore, the coupling gear sleeve will not receive the axial force from the rotating lead screw, and it will be very labor-saving for the user to move the coupling gear sleeve by using the driving member. At the same time, the strength requirement for the coupling gear sleeve itself is also reduced. In addition, this is also beneficial to extending the service life of the clutch device.

[0011] Preferably, the linear actuator further includes a first friction sleeve and a self-locking torsion spring sleeved outside the first friction sleeve, and the axial limiting kit includes the first friction sleeve.

[0012] Preferably, the linear actuator further includes a second friction sleeve. The first friction sleeve and the second friction sleeve are axially abutted. A release torsion spring is sleeved on the second friction sleeve, and the axial limiting kit includes the first friction sleeve and the second friction sleeve.

[0013] Preferably, the first friction sleeve and the second friction sleeve are arranged axially side by side, and the outer end faces of the first friction sleeve and the second friction sleeve are abutted.

[0014] Preferably, the second friction sleeve is sleeved outside the first friction sleeve, and the outer end face of the first friction sleeve abuts against the inner end face of the second friction sleeve.

[0015] Preferably, a bearing is installed on the second friction sleeve, a bearing groove for installing the bearing is provided on the housing, and the bearing is axially limited to the housing.

[0016] Preferably, the first friction sleeve is arranged at the end of the rotating lead screw, the housing includes a tail pull head at the end, and the tail pull head is axially limited to the second friction sleeve.

[0017] Preferably, a spline sleeve is provided between the rotating lead screw and the coupling gear sleeve, and the spline sleeve is axially limited with respect to the first friction sleeve. The axial limiting kit includes a spline sleeve, a first friction sleeve, and a second friction sleeve.

[0018] Preferably, a tapered roller bearing is provided between the second friction sleeve and the tail pull head.

[0019] Preferably, the linear actuator further includes a manual release assembly. The manual release assembly further includes a pull rod and a swing rod. The pull rod is axially movably arranged relative to the rotating lead screw. The swing rod is rotatably connected to the pull rod. When the pull rod is pulled, the swing rod swings to axially push the coupling gear sleeve.

[0020] 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

[0021] The present invention will be further described below with reference to the drawings:

[0022] Figure 1 Overall schematic diagram of the linear actuator according to Embodiment 1 of the present invention Figure 1 ;

[0023] Figure 2 Overall schematic diagram of the linear actuator according to Embodiment 1 of the present invention Figure 2 ;

[0024] Figure 3 Exploded schematic diagram of the linear actuator according to Embodiment 1 of the present invention;

[0025] Figure 4 Partially enlarged schematic diagram of the linear actuator according to Embodiment 1 of the present invention;

[0026] Figure 5 Exploded schematic diagram of the internal parts of the linear actuator according to Embodiment 1 of the present invention;

[0027] Figure 6 Exploded schematic diagram of the manual rotation release device of the linear actuator according to Embodiment 1 of the present invention;

[0028] Figure 7 Cross-sectional view of the linear actuator manual rotation release device according to Embodiment 1 of the present invention;

[0029] Figure 8 Structural schematic diagram of the linear actuator according to Embodiment 2 of the present invention;

[0030] Figure 9 Partially cut-away schematic diagram of the linear actuator according to Embodiment 2 of the present invention;

[0031] Figure 10This is an enlarged schematic view of a partially cut - away linear actuator in Embodiment 2 of the present invention;

[0032] Figure 11 This is an exploded schematic view of the internal parts in the linear actuator of Embodiment 2 of the present invention. Detailed implementation manners

[0033] The following explains and illustrates the technical solutions of the embodiments of the present invention with reference to the accompanying drawings of the embodiments of the present invention. However, the following embodiments are only the preferred embodiments of the present invention, not all of them. Based on the embodiments in the implementation manners, other embodiments obtained by those skilled in the art without creative efforts all fall within the protection scope of the present invention.

[0034] In the following description, terms such as "inner", "outer", "upper", "lower", "left", "right" indicating orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings. It is only for the convenience of describing the embodiments and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation of the present invention.

[0035] Embodiment 1:

[0036] As Figures 1 to 7 shown, this embodiment is a linear actuator. A linear actuator is usually also called a linear driver or an electric push rod. The linear actuator includes a housing, an outer tube 13, an inner tube 14, a drive motor 15, a transmission assembly, a rotating lead screw 20, and a transmission nut 21. The drive motor 15 drives the rotating lead screw 20 to rotate through the transmission assembly. The rotation of the rotating lead screw 20 drives the transmission nut 21 to move axially along the rotating lead screw 20. The transmission nut 21 is fixedly connected to the inner tube 14. When the transmission nut 21 moves axially, it drives the inner tube 14 to move axially relative to the outer tube 13 and the housing. The outer end of the inner tube 14 is then connected to the target to be driven. The linear actuator in this embodiment further includes:

[0037] A clutch device, arranged between the transmission assembly and the rotating lead screw 20, for connecting or disconnecting the power connection between the transmission assembly and the rotating lead screw 20;

[0038] The specific structure of the clutch device in this embodiment is as follows: the clutch device includes a coupling sleeve 31, and the coupling sleeve 31 itself is mounted on the rotating screw 20 through a flat position, that is, in the circumferential direction, the coupling sleeve 31 and the rotating screw 20 rotate synchronously, but in the axial direction, the coupling sleeve 31 can move axially along the rotating screw 20, and the coupling sleeve 31 has a plurality of tooth-like portions toward the transmission worm gear 22, and the end face of the transmission worm gear 22 is provided with tooth grooves that match the transmission of the coupling sleeve 31. When the coupling sleeve 31 is close to the transmission worm gear 22, the tooth-like portions are inserted into the tooth grooves, and the coupling sleeve 31 and the transmission worm gear 22 realize synchronous rotation. When the coupling sleeve 31 is away from the transmission worm gear 22, the tooth-like portions are separated from the tooth grooves, and the coupling sleeve 31 is separated from the transmission worm gear 22, that is, the rotating screw 20 will be in a non-powered connection state. Reference Figure 4 In the figure, the coupling sleeve 31 is inserted into the transmission worm gear 22.

[0039] In this embodiment, the rotating screw 20 is sheathed with an axial limiting kit, which is axially offset from the outer shell. The axial limiting kit and the rotating screw 20 are kept positioned in the axial direction. When the rotating screw 20 is subjected to an axial load, the rotating screw 20 transmits the axial force to the outer shell through the axial limiting kit, and no axial force is transmitted between the coupling gear sleeve 31 and the axial limiting kit in the axial direction.

[0040] The axial limit kit itself is axially limited with the rotating screw 20, and secondly, the axial limit kit is also axially limited with the housing. Such an installation method allows the axial force on the rotating screw to be transmitted to the housing through the axial limit kit, while no axial force is transmitted between the coupling gear sleeve 31 and the axial limit kit. Therefore, the coupling gear sleeve 31 will not receive the axial force from the rotating screw. The user will save effort when using the driving component to move the coupling gear sleeve 31. At the same time, the strength requirement of the coupling gear sleeve 31 itself is also reduced. In addition, this is also beneficial to extending the service life of the clutch device.

[0041] In this embodiment, the linear actuator further includes a self-locking device, which generates friction resistance to the rotating screw 20 when the rotating screw 20 reverses. The structure of the self-locking device in this embodiment includes a first friction sleeve 41, a second friction sleeve 42, a release torsion spring 40, and a self-locking torsion spring 43. The first friction sleeve 41 and the second friction sleeve 42 are respectively mounted on the rotating screw 20. The first friction sleeve 41 and the rotating screw 20 are positioned by flat positions, that is, in the circumferential direction, the first friction sleeve 41 and the rotating screw 20 rotate synchronously, while the second friction sleeve 42 rotates freely relative to the rotating screw 20. In the axial direction, the axial end faces of the first friction sleeve 41 and the second friction sleeve 42 abut against each other. At the same time, the release torsion spring 40 is mounted on the second friction sleeve 42. The release torsion spring 40 always holds the second friction sleeve 42 tightly in the initial state. The first friction sleeve 41 is mounted with a self-locking torsion spring 43.

[0042] refer to Figure 4 As shown, when the inner tube 14 of the linear actuator extends to a predetermined position and has a tendency to retract, the rotating screw 20 will be subjected to an axial force. After being subjected to the axial force, the rotating screw 20 will transfer the axial force to the first friction sleeve 41, and the first friction sleeve 41 will transfer the axial force to the second friction sleeve 42. The second friction sleeve 42 is provided with a second bearing 44, and the second bearing 44 is axially limited by a limiting step 111 on the outer shell, so the axial force is directly transferred to the outer shell through the second bearing 44 on the second friction sleeve 42.

[0043] Therefore, based on the self-locking device in this embodiment, the first friction sleeve 41, the second friction sleeve 42, and the second bearing 44 in the self-locking device naturally constitute an axial limit kit, and the rotating screw 20 directly transmits the axial force to the housing through the axial limit kit. Since the position of the entire clutch device is at the rear end of the limit step 111 of the housing, the clutch device itself is not affected by the axial force during the entire axial force transmission process. In such an environment, the user will save more effort when turning the coupling gear sleeve 31 in the clutch device. At the same time, since the clutch device is not subjected to the axial force from the rotating screw 20, the service life of the clutch device can be greatly improved. Of course, it should be noted that if there is no self-locking device in the linear actuator, a structure similar to a sleeve can be additionally provided on the rotating screw 20 as an axial limit kit.

[0044] In this embodiment, the first friction sleeve 41 preferably includes a front sleeve 411 and a rear sleeve 412. A thrust bearing is used to abut the front sleeve 411 and the rear sleeve 412 in the axial middle. In other embodiments, the first friction sleeve 41 can be in the form of an integrated sleeve.

[0045] A hand-pull release assembly, the hand-pull release assembly includes a first driving member and a second driving member, the first driving member is connected to a clutch device, the second driving member is used to connect to the self-locking device, the hand-pull release assembly includes an initial state and a fully released state, during the process from the initial state to the fully released state, the first driving member drives the clutch device to disconnect the power connection, and the second driving member drives the release torsion spring 40 to loosen.

[0046] In the linear actuator of this embodiment, both a clutch device and a self-locking device are provided, making the functions of the linear actuator more comprehensive. Moreover, the combination of the clutch device and the self-locking device has an advantage. Since the power is disconnected by the clutch device, the rotating lead screw 20 is almost in a completely free rotation state, which easily causes the linear actuator to retract too fast. By setting the self-locking device, it can just provide a certain resistance to prevent the rotating lead screw 20 from rotating too fast, thereby avoiding the transmission nut 21 from retracting too fast.

[0047] Secondly, the self-locking device in this embodiment also has a release torsion spring 40, that is, the self-locking device itself can also be unlocked. When the release torsion spring 40 is loosened, the self-locking device is in an unlocked state. At this time, whether the linear actuator rotates forward or backward, the self-locking device hardly generates resistance to the rotating lead screw 20. This situation can make the linear actuator in a rapid release state, that is, it can retract quickly.

[0048] Finally, in the linear actuator of this embodiment, a hand-pull release assembly is provided. The hand-pull release assembly includes a first driving member and a second driving member. The first driving member and the second driving member are respectively used to drive the clutch device and the self-locking device. When the linear actuator needs to be quickly released, the operator operates the hand-pull release assembly to make it in the fully released state, which can make the clutch device in a disconnected state and the self-locking device in an unlocked state at the same time. The user only needs to operate one hand-pull release assembly to control two devices, which is very convenient to operate.

[0049] In this embodiment, the first driving member is mainly used to move the coupling gear sleeve 31 axially. At the same time, in order to make the clutch device reset after the first driving member moves it, the clutch device in this embodiment further includes a return spring 32 that generates an axial return force on the coupling gear sleeve 31. A limiting end 201 is provided at the end of the rotating lead screw 20. The return spring 32 is sleeved on the rotating lead screw 20 and is limited at both ends between the limiting end 201 and the coupling gear sleeve 31.

[0050] The housing in this embodiment includes an upper housing 11 and a lower housing 12. A first bearing 33 is provided between the coupling gear sleeve 31 and the housing to reduce the frictional resistance when the coupling gear sleeve 31 rotates.

[0051] Structure of the first driving member in this embodiment: The first driving member includes a swing rod 51 rotatably mounted on the housing. The hand-pulling release assembly further includes a pull rod 52 axially movably arranged relative to the rotating lead screw 20. The swing rod 51 is connected to the pull rod 52. Specifically, during installation, the upper end of the swing rod 51 is rotatably connected to the pull rod 52, the middle of the swing rod 51 is rotatably connected to the upper housing 11, and a dial block 53 is connected to the lower end of the swing rod 51. The dial block 53 is relatively fixed to the coupling gear sleeve 31. Specifically, in this embodiment, the dial block 53 is connected to the first bearing 33 on the coupling gear sleeve 31. When the pull rod 52 is pulled, the swing rod 51 swings, and accordingly, the dial block 53 will push the coupling gear sleeve 31 to move axially.

[0052] When the inner tube 14 in the linear actuator extends normally, the driving motor 15 drives the rotating lead screw 20 to rotate forward through the clutch device. When the inner tube 14 extends to a predetermined position, the driving motor 15 stops. At this position, when the inner tube 14 has a tendency to retract, the axial end faces of the first friction sleeve 41 and the second friction sleeve 42 are in contact with each other. Since the self-locking torsion spring 43 has a holding resistance effect on the first friction sleeve 41, and at the same time, the second friction sleeve 42 is also held by the release torsion spring 40 in the normal state. When the end faces of the first friction sleeve 41 and the second friction sleeve 42 are in contact with each other, a frictional resistance is generated between the two, and this frictional resistance generates a resistance to prevent the rotating lead screw 20 from reversing to complete the self-locking force.

[0053] When the linear actuator needs to retract normally, the driving motor 15 drives the rotating lead screw 20 to rotate reversely through the clutch device. At this time, the rotation torque of the rotating lead screw 20 will overcome the self-locking force provided by the self-locking device, and the rotating lead screw 20 will continue to rotate reversely, so that the transmission nut 21 drives the inner tube 14 to retract.

[0054] When the linear actuator needs to retract quickly when it extends to a predetermined position, this embodiment can unlock the self-locking device to achieve the purpose of quick release. In this embodiment, the unlocking is mainly realized through the second driving member. The specific structure is as follows: It can be combined with Figures 2 to 4As shown, the second driving member includes a pushing block 54. The pushing block 54 is provided with a guiding surface 541. The release torsion spring 40 includes a radially extending pin 401. In this embodiment, the pin 401 extends out of the top of the housing. The guiding surface 541 is arranged on the side surface of the pushing block 54. The pushing block 54 is fixedly connected to the pull rod 52. That is, in this embodiment, the self-locking device and the clutch device share a pull rod 52. When the pull rod 52 is pulled, the guiding surface 541 on the pushing block 54 abuts against the pin 401, so that the release torsion spring 40 expands outward. When the release torsion spring 40 expands outward, the resistance between the release torsion spring 40 and the second friction sleeve 42 will correspondingly decrease. In this state, when the end faces of the first friction sleeve 41 and the second friction sleeve 42 are in contact, the second friction sleeve 42 will rotate synchronously with the first friction sleeve 41. In this way, the first friction sleeve 41 will not generate resistance to the rotating lead screw 20, thus achieving the purpose of the rotating lead screw 20 having no resistance. At this time, if the clutch device is disconnected, and at the same time the self-locking device is unlocked, in this state, the rotating lead screw 20 is basically in a free idling state, and the transmission nut 21 can be quickly retracted.

[0055] In addition, in this embodiment, the release method of gradually pushing the release torsion spring 40 by using the guiding surface 541 can achieve the purpose of gradually reducing the self-locking force, so that the self-locking force will not disappear immediately, so as to achieve a purpose of stepless adjustment.

[0056] In order to better optimize the operation of the clutch device and the self-locking device, in this embodiment, the operation sequence of the clutch device and the self-locking device is optimized. As Figure 2 shown, a waist-shaped hole for adjustment is provided on the pull rod 52. The pushing block 54 is fixed on the waist-shaped hole by a fastening screw. The design of this waist-shaped hole is mainly used to adjust the initial position of the pushing block 54. There are two purposes for setting the initial position. One is to make up for some actual assembly errors so that the pushing block 54 can more precisely abut against the release torsion spring 40. The other is as described in this article, the operation sequence between the pushing block 54 and the clutch device can be adjusted. As Figure 2 shown, in the initial state, the guiding surface 541 of the pushing block 54 needs to move a certain stroke before it contacts the pin 401 of the release torsion spring 40. During this stroke, it can be understood as the idle stroke of the pushing block 54. During this idle stroke, the clutch device operates normally. The purpose formed in this way is that the coupling gear sleeve 31 will be first toggled. At the same time, when resetting, the self-locking device self-locks first, and then the clutch device makes a power connection. The advantage of this is that after the self-locking device generates a self-locking force, the rotation speed of the rotating lead screw 20 will decrease, so that when the coupling gear sleeve 31 engages with the transmission worm 22, the coupling gear sleeve 31 and the transmission worm 22 will not be damaged, and the service life can be greatly extended.

[0057] In addition, in order to enable the user to better perceive the size of the release amplitude, in the present embodiment, a toothed bar 521 is provided on the pull rod 52, and a movable latch 522 is provided on the outer shell. The movable latch 522 is connected with a spring. When the pull rod 52 is pulled, the movable latch 522 is latched into the toothed bar 521 one by one. The position of the movable latch 522 on the toothed bar 521 can be used to sense the pulling stroke of the pull rod 52.

[0058] It should be noted that the structure of the self-locking device and the clutch device is not limited to the structure shown in this embodiment. Taking the self-locking device as an example, the self-locking device may only include a single third friction sleeve, the third friction sleeve rotates synchronously with the rotating screw, and the release torsion spring is sleeved on the third friction sleeve. In the initial state, the release torsion spring holds the third friction sleeve tightly to generate resistance to the rotating screw, which is equivalent to the release torsion spring being a self-locking torsion spring. When the release torsion spring is pushed by the push block, the resistance of the release torsion spring to the third friction sleeve disappears. Taking the clutch device as an example, the clutch device can be realized by a combination of other spline sleeves and splines. In this regard, the second embodiment below also shows different implementation methods of the self-locking device and the clutch device.

[0059] like Figures 6 to 7 As shown, in order to further enhance the release function of the linear actuator, the linear actuator in this embodiment is connected to a front pull head 16 at the end of the inner tube 14, and a hand-twist release device 17 is connected between the front pull head 16 and the end of the inner tube 14. The hand-twist release device 17 can cut off the power connection between the front pull head 16 and the inner tube 14.

[0060] Specifically, the hand-twist release device 17 includes a knob sleeve 171, a connecting sleeve seat 172 and a hand-twist release torsion spring 173. The connecting sleeve seat 172 is fixedly connected to the inner tube 14, and the front pulling head 16 is sleeved with the connecting sleeve seat 172. The hand-twist release torsion spring 173 is arranged between the connecting sleeve seat 172 and the front pulling head 16. Specifically, the hand-twist release torsion spring 173 is sleeved on the outside of the front pulling head 16. At the same time, the hand-twist release torsion spring 173 also has a corresponding pin 1731. The pin 401 passes through the notch on the connecting sleeve seat 172 and abuts against the knob sleeve 171. When the knob sleeve 171 is rotated, it is used to toggle the hand-twist release torsion spring 173 to radially contract or radially expand, thereby controlling the friction resistance of the hand-twist release torsion spring 173 to the front pulling head 16.

[0061] Embodiment 2:

[0062] like Figures 8 to 11 As shown, the operating principle of this embodiment is similar to that of the first embodiment, and the main difference lies in the specific structures of the self-locking device, the clutch device, the first driving component, and the second driving component.

[0063] The self-locking device of this embodiment: In the first embodiment, the first friction sleeve 41 and the second friction sleeve 42 are axially arranged side by side, and the outer end faces of the first friction sleeve 41 and the second friction sleeve 42 are abutted against each other, while in this embodiment, the second friction sleeve 42 is sleeved outside the first friction sleeve 41, and the outer end face of the first friction sleeve 41 is abutted against the inner end face of the second friction sleeve 42. The installation between the first friction sleeve 41 and the rotating screw rod 20 is the same as that in the first embodiment. The first friction sleeve 41 still rotates synchronously with the rotating screw rod 20. At the same time, the outside of the first friction sleeve 41 is also sleeved with a self-locking torsion spring 43, and the release torsion spring 40 is still sleeved outside the second friction sleeve 42. The working principle is similar to that of the first embodiment, that is, the self-locking force of the self-locking torsion spring 43 mainly comes from the end face friction force of the first friction sleeve 41 and the second friction sleeve 42.

[0064] The first friction sleeve 41 in this embodiment has a similar structure to that of the first embodiment, and also includes a front sleeve 411 and a rear sleeve 412. A thrust bearing is provided between the front sleeve 411 and the rear sleeve 412. The self-locking torsion spring 43 is simultaneously sleeved on the outside of the front sleeve 411 and the rear sleeve 412. The rear sleeve 412 abuts against the inner end surface of the second friction sleeve 42.

[0065] The advantage of this self-locking device is that the installation space is smaller, mainly the axial space will be smaller, which is conducive to reducing the volume of the entire linear actuator.

[0066] The clutch device of this embodiment: The clutch device of this embodiment also includes a spline sleeve 34, which is located between the rotating screw 20 and the coupling gear sleeve 31. The spline sleeve 34 itself rotates synchronously with the rotating screw 20, and the torque transmission is mainly achieved by the flat position between the spline sleeve 34 and the rotating screw 20, while the coupling gear sleeve 31 and the transmission worm gear 22 always maintain synchronous rotation, and the first driving component mainly promotes the clutch between the coupling gear sleeve 31 and the spline sleeve 34.

[0067] The first driving member in this embodiment is slightly different from that in the first embodiment, and adopts a toggle block 55 , which is rotationally connected to the pull rod 52 . When the pull rod 52 is pulled, the toggle block 55 drives the coupling gear sleeve 31 to move axially.

[0068] In this embodiment, the second driving member is directly integrated with the pull rod 52. Figure 8 As shown in FIG. 5 , a guide surface 541 is provided on the pull rod 52 .

[0069] In addition, compared with the first embodiment, the present embodiment eliminates the hand-twist release device 17 .

[0070] The clutch device in this embodiment is the same as that in the first embodiment. The coupling sleeve itself is not subjected to the axial force from the rotating screw 20. The axial force transmission in this embodiment is as follows:

[0071] When the inner tube 14 of the linear actuator extends to a predetermined position and has a tendency to retract, the rotating lead screw 20 will be subjected to an axial force. The spline sleeve 34 abuts against the shoulder position of the rotating lead screw 20. Therefore, the axial force of the rotating lead screw 20 is transmitted to the spline sleeve 34 immediately. The end face of the spline sleeve 34 abuts against the end face of the first friction sleeve 41, that is, the spline sleeve 34 and the first friction sleeve 41 are axially limited. Therefore, the axial force will be transmitted to the first friction sleeve 41. The end face of the first friction sleeve 41 abuts against the inner end face of the second friction sleeve 42. Therefore, the axial force is transmitted to the second friction sleeve 42. There is a tapered roller bearing 23 between the end face of the second friction sleeve 42 and the tail pull head 10. Therefore, the axial force is finally transmitted to the tail pull head 10 through the tapered roller bearing 23.

[0072] In this embodiment, the spline sleeve 34, the first friction sleeve 41, and the second friction sleeve 42 together form an axial limiting kit. The rotating lead screw 20 transmits the axial force to the tail pull head 10 through the axial limiting kit. From the perspective of the entire axial force transmission process, the coupling tooth sleeve in this embodiment is never subjected to the axial force. Therefore, it is also very labor-saving for the first driving member to toggle the coupling tooth sleeve.

[0073] The above is only the 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 content 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 smooth clutch engagement, comprising a housing, a driving worm gear, a rotating lead screw, and a driving nut. The driving worm gear drives the rotating lead screw to rotate, and the rotation of the rotating lead screw drives the driving nut to move axially along the rotating lead screw. A clutch device is provided between the driving worm gear and the rotating lead screw, and it is characterized in that, The clutch device includes a coupling gear sleeve that can axially move relative to the rotating worm wheel. An axial limit kit is sleeved outside the rotating lead screw. The axial limit kit axially abuts against the housing. The axial limit kit and the rotating lead screw are axially positioned. When the rotating lead screw is subjected to an axial load, the rotating lead screw transmits the axial force to the housing through the axial limit kit. No axial force is transmitted axially between the coupling gear sleeve and the axial limit kit. The linear actuator further includes a first friction sleeve and a self-locking torsion spring sleeved outside the first friction sleeve. The axial limit kit includes the first friction sleeve. The linear actuator further includes a second friction sleeve. The first friction sleeve and the second friction sleeve axially abut against each other. A release torsion spring is sleeved on the second friction sleeve. The axial limit kit includes the first friction sleeve and the second friction sleeve.

2. The smoothly engaging linear actuator according to claim 1, wherein, The first friction sleeve and the second friction sleeve are arranged side by side axially, and the outer end faces of the first friction sleeve and the second friction sleeve abut against each other.

3. The smoothly engaging linear actuator according to claim 1, wherein, The second friction sleeve is sleeved outside the first friction sleeve, and the outer end face of the first friction sleeve abuts against the inner end face of the second friction sleeve.

4. The linear actuator with smooth clutch as claimed in claim 2, wherein, A bearing is installed on the second friction sleeve. A bearing groove for installing the bearing is provided on the housing. The bearing is axially limited with respect to the housing.

5. The linear actuator with smooth clutch as claimed in claim 1, wherein The first friction sleeve is arranged at the end of the rotating lead screw. The housing includes a tail pull head at the end. Axial limitation is provided between the tail pull head and the second friction sleeve.

6. The linear actuator with smooth clutch as claimed in claim 5, wherein A spline sleeve is provided between the rotating lead screw and the coupling gear sleeve. Axial limitation is provided between the spline sleeve and the first friction sleeve. The axial limit kit includes the spline sleeve, the first friction sleeve, and the second friction sleeve.

7. The smoothly disengaging linear actuator according to claim 5, wherein A tapered roller bearing is provided between the second friction sleeve and the tail pull head.

8. The linear actuator with smooth clutch as claimed in claim 1, wherein, The linear actuator further includes a hand-pull release assembly. The hand-pull release assembly further includes a pull rod and a swing rod. The pull rod is axially movably arranged relative to the rotating lead screw. The swing rod is rotatably connected to the pull rod. When the pull rod is pulled, the swing rod swings to axially push the coupling gear sleeve.

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