CN108518465B

CN108518465B - Linear actuator

Info

Publication number: CN108518465B
Application number: CN201810352617.8A
Authority: CN
Inventors: 陆小健; 胡仁昌; 翟鑫; 石鑫; 邢科亮
Original assignee: Zhejiang Jiecang Linear Motion Technology Co Ltd
Current assignee: Zhejiang Jiecang Linear Motion Technology Co Ltd
Priority date: 2018-04-19
Filing date: 2018-04-19
Publication date: 2024-06-25
Anticipated expiration: 2038-04-19
Also published as: CN108518465A

Abstract

The invention discloses a linear actuator, which comprises a driving motor, a transmission worm, a worm wheel, a screw rod and a nut, wherein the driving motor is connected with the transmission worm, the transmission worm drives the worm wheel to rotate, the worm wheel rotates to drive the screw rod to rotate, the screw rod rotates to drive the nut to axially move, and the linear actuator further comprises: the planetary gear assembly is arranged between the worm wheel and the screw rod and comprises an annular gear, a sun gear, a planetary gear and a planetary carrier, wherein the sun gear and the worm wheel synchronously rotate, and the planetary carrier and the screw rod synchronously rotate; and the brake is used for braking the inner gear ring and comprises an outer gear ring. The invention has the advantages that the thrust is improved by utilizing the planetary gear assembly, and meanwhile, the release is also carried out by utilizing the planetary gear assembly, so that the structure design is more compact.

Description

Linear actuator

Technical Field

The invention relates to a linear actuator, and belongs to the technical field of linear transmission.

Background

The linear actuator, also called electric putter, wide application is in fields such as furniture, medical equipment, solar energy power generation, and its main structure includes driving motor, drive worm, worm wheel, lead screw, nut, and the theory of operation is that driving motor drive worm rotates, thereby drive worm wheel rotation with worm wheel meshing, and the worm wheel rotates and drives the lead screw and rotate, and the lead screw rotates and drives nut axial displacement, and the nut is connected with the inner tube generally to realize the concertina movement of inner tube.

In the prior art, a plurality of release mechanisms are arranged between transmission parts of the linear actuator, the release mechanisms aim at reversely driving a screw rod to rotate by a nut when a driving motor loses power, the release mechanisms disclosed at present are usually realized through the clutch action between two coupling parts, the internal space of the linear actuator is very limited, and the additional two coupling parts are added to realize the clutch, so that larger space can be occupied.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide the linear actuator which is more compact in structural design by utilizing the planetary gear assembly to improve the thrust and simultaneously releasing the thrust by means of the planetary gear assembly.

The technical problems are solved, and the invention adopts the following technical scheme:

The utility model provides a linear actuator, includes driving motor, drive worm, worm wheel, lead screw, nut, and driving motor connects drive worm, and drive worm drives the worm wheel rotation, and the worm wheel rotation drives the lead screw and rotates, and the lead screw rotates and drives nut axial displacement still includes:

The planetary gear assembly is arranged between the worm wheel and the screw rod and comprises an annular gear, a sun gear, a planetary gear and a planetary carrier, wherein the sun gear and the worm wheel synchronously rotate, and the planetary carrier and the screw rod synchronously rotate;

the brake is used for braking the inner gear ring and comprises an outer gear ring, the outer gear ring and the inner gear ring synchronously rotate,

The external gear ring is meshed with a brake worm.

The beneficial effects of the invention are that:

1. A planetary gear assembly is additionally arranged between the worm wheel and the screw rod, and the rotation speed of the worm wheel can be reduced and the torque of the screw rod can be improved through the transmission function of the planetary gear assembly, so that the screw rod has larger thrust;

2. A brake is arranged, the brake brakes an inner gear ring in a planetary gear assembly, and the working principle of the brake is as follows:

When the linear actuator does not need the release function, i.e. in the unreleased state, the brake brakes the ring gear, and the ring gear cannot rotate freely. When the driving motor is driven actively, the worm wheel drives the sun gear to rotate, the sun gear drives the planetary gear to rotate in the internal gear ring, and the planet carrier correspondingly rotates, and the rotation of the lead screw is finally realized because the planet carrier and the lead screw synchronously rotate;

In contrast, in the unreleased state, when the driving motor loses power and the screw rod drives in the reverse direction, the screw rod is required to drive the planet carrier to rotate, and the planet carrier can only rotate under the condition that the sun gear rotates, however, the sun gear is kept synchronous with the driving motor, so that the screw rod can not rotate under the condition that the sun gear does not move, in other words, when the driving motor loses power, the screw rod can not rotate in the reverse direction.

However, in this case, when the user needs to rotate the screw rod in the opposite direction even if the driving motor loses power, a release function is needed, and in the release state, the brake releases the ring gear, so that the ring gear can rotate freely. When the driving motor loses power, the screw rod drives in the reverse direction to drive the planet carrier to rotate, and the sun gear still cannot rotate at the moment, but the inner gear ring can rotate freely at the moment, and the planet carrier and the inner gear ring rotate together along the axis of the sun gear at the moment. In other words, in the released state, even if the drive motor loses power, the screw can be freely rotated.

The invention uses the structure property of the planetary gear assembly to complete the release function of the linear actuator, belongs to a new structure conception, is equivalent to the planetary gear assembly in the invention not only being used for improving the transmission torque, but also being one part of the release mechanism in the linear actuator, and compared with the traditional release mechanism which needs two additional coupling parts, the release mechanism in the invention does not need two coupling parts, because the annular gear is used as one part in the planetary gear assembly and simultaneously also is used as the coupling part in the release mechanism, namely, the annular gear can simultaneously complete two functions in the invention, and the structure design ensures that the internal structure of the linear actuator is more compact.

Preferably, the linear actuator further comprises an outer gear ring, the outer gear ring and the inner gear ring rotate synchronously, and the outer gear ring is meshed with a brake worm.

Preferably, the inner gear ring and the outer gear ring are of an integral structure.

Preferably, a brake torsion spring is sleeved outside the brake worm, and the brake torsion spring contracts the torsion spring inner ring or enlarges the torsion spring inner ring so as to lock or unlock the brake worm.

Preferably, the linear actuator further comprises a base and a puller, the braking torsion spring comprises a torsion spring main body, a first pin and a second pin, the torsion spring main body is sleeved on the braking worm, the first pin is fixed on the base, the second pin is pulled by the puller, and under the pulling action of the puller, the braking torsion spring expands radially to release the braking worm.

Preferably, a pull rod is arranged between the puller and the braking torsion spring, the pull rod is rotatably arranged on the base, and the second pin is positioned and arranged on the pull rod.

Preferably, the pull rod comprises a pull rod main body and a sleeve, and a positioning groove for positioning the second pin is formed in the inner wall of the sleeve.

Preferably, a sliding block is connected between the pull rod and the puller, the sliding block is slidably mounted on the base, a walking groove is formed in the sliding block, a rolling shaft is arranged on the pull rod, and the rolling shaft is slidably and rotationally matched with the walking groove.

Preferably, a friction sleeve is arranged between the braking worm and the braking torsion spring.

Preferably, the linear actuator is movably provided with a coupling plug-in unit, the brake worm is provided with a coupling socket matched with the coupling plug-in unit, and the coupling plug-in unit is inserted into the coupling socket to prevent the brake worm from rotating.

Preferably, the linear actuator further comprises a gear box, the planetary gear assembly is mounted in the gear box, and the brake worm is rotatably mounted in the gear box.

Preferably, the sun gear is located at the center of the inner gear ring, at least one planetary gear is meshed between the sun gear and the inner gear ring, the planetary gear is installed on the planet carrier, and the planet carrier is fixedly connected with the screw rod.

Preferably, the linear actuator further comprises an auxiliary driver for driving the braking worm to rotate, and the auxiliary driver is electrically driven or hand-driven.

Preferably, the brake comprises an inner gear ring outer torsion spring sleeved outside the inner gear ring.

Preferably, a unidirectional locking coupler is arranged between the worm wheel and the sun gear, the coupler comprises a transmission torsion spring and a damping ring sleeved with the transmission torsion spring, the worm wheel transmits torque to the transmission torsion spring and enables the transmission torsion spring to be in clearance fit with the damping ring in a worm wheel driving state and a sun gear driven state, and the screw rod transmits torque to the transmission torsion spring and enables the transmission torsion spring to be in interference fit with the damping ring in a worm wheel driving state and a sun gear driving state.

Preferably, the coupling comprises a first poking plate and a second poking plate which are circumferentially arranged at intervals, the first poking plate is used for being connected with a worm gear, the second poking plate is used for being connected with a sun gear, a transmission torsion spring is sleeved on the first poking plate and the second poking plate, the transmission torsion spring comprises bending pins, and the bending pins are clamped between the first poking plate and the second poking plate.

Preferably, the transmission torsion spring is sleeved outside the first shifting plate and the second shifting plate, the damping ring is sleeved outside the transmission torsion spring, the bending pin of the transmission torsion spring is bent radially inwards, and when the first shifting plate transmits torque to the transmission torsion spring, the bending pin is shifted towards the screwing direction of the transmission torsion spring.

Preferably, the center of the worm wheel is provided with a center hole, the first poking piece is a first arc piece arranged along the circumferential direction of the center hole, the second poking piece is a second arc piece protruding on the sun gear along the axial direction, and the second arc piece penetrates through the center hole and forms a round surrounding wall with a notch with the first arc piece.

Preferably, the linear actuator further comprises a supporting seat arranged on one side of the tail end of the planetary gear assembly, a first sliding sleeve is sleeved on the supporting seat, a first limiting check ring is arranged at the tail end of the first sliding sleeve, and the sun gear is sleeved on the first sliding sleeve and is axially positioned between the first limiting check ring and the planet carrier or the screw rod.

Preferably, a friction pad is arranged between the front end of the sun gear and the planet carrier or the screw rod.

Preferably, the support seat comprises a center column and an outer ring wall positioned on the outer side of the periphery of the center column, the first sliding sleeve is sleeved on the center column, the outer ring wall is sleeved with a second sliding sleeve, and the worm wheel is sleeved on the second sliding sleeve.

These features and advantages of the present invention will be disclosed in detail in the following detailed description and the accompanying drawings.

Drawings

The invention is further described with reference to the accompanying drawings:

FIG. 1 is a schematic diagram of a linear actuator according to an embodiment of the present invention;

FIG. 2 is a schematic view of the structure of FIG. 1 with the lid removed;

FIG. 3 is a schematic explosion diagram of a linear actuator according to an embodiment I of the present invention;

FIG. 4 is an enlarged schematic view of FIG. 3 at A;

FIG. 5 is a schematic explosion diagram of a linear actuator according to a first embodiment of the present invention;

FIG. 6 is a schematic explosion diagram III of a linear actuator according to an embodiment of the present invention;

FIG. 7 is a schematic explosion diagram of a linear actuator according to an embodiment of the present invention;

FIG. 8 is a schematic diagram illustrating an internal structure of a first embodiment of the present invention;

fig. 9 is a schematic cross-sectional view of a first embodiment of the present invention.

Detailed Description

The technical solutions of the embodiments of the present invention will be explained and illustrated below with reference to the drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, and not all embodiments. Based on the examples in the implementation manner, other examples obtained by a person skilled in the art without making creative efforts fall within the protection scope of the present invention.

In the following description, the terms such as "inner", "outer", "upper", "lower", "left", "right", etc. are used to indicate an orientation or a positional relationship based on that shown in the drawings, and are merely for convenience of description of the embodiments and to simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

Example 1

As shown in fig. 1 to 9, the present embodiment is a linear actuator, which includes a driving motor 1, a driving worm 2, a worm wheel 3, a screw rod 4, and a nut 5, wherein the driving motor 1 is connected with the driving worm 2, the driving worm 2 drives the worm wheel 3 to rotate, the worm wheel 3 rotates to drive the screw rod 4 to rotate, the screw rod 4 rotates to drive the nut 5 to axially move, and further includes a housing 6, an outer tube 7, and an inner tube 8, the nut 5 is connected with the inner tube 8, the housing 6 is connected with the outer tube 7, the driving motor 1 is fixedly installed in the housing 6, and the axial movement of the nut 5 is finally expressed as the axial relative displacement between the inner tube 8 and the outer tube 7.

In this embodiment, a planetary gear 12 assembly is further disposed between the worm wheel 3 and the screw rod 4, and in particular, as shown in fig. 5 to 8, the planetary gear 12 assembly is used for transmission connection between the worm wheel 3 and the screw rod 4, and the planetary gear 12 assembly includes an inner gear ring 10, a sun gear 11, a planetary gear 12, and a planet carrier 13, wherein the sun gear 11 is located in the inner gear ring 10, the planetary gear 12 is meshed between the inner gear ring 10 and the sun gear 11, and meanwhile, the axis of the planetary gear 12 is rotatably installed on the planet carrier 13. In this embodiment, the sun gear 11 rotates synchronously with the worm wheel 3, the planet carrier 13 rotates synchronously with the screw rod 4, and in this embodiment, the planet carrier 13 is preferably connected with the screw rod 4 through spline fit, a planetary gear 12 assembly is additionally arranged between the worm wheel 3 and the screw rod 4, and through the transmission function of the planetary gear 12 assembly, the rotation speed of the worm wheel 3 can be reduced, the torque of the screw rod 4 can be improved, so that the screw rod 4 has larger thrust;

Further, a brake for braking the ring gear 10 to restrict free rotation thereof is provided in the present embodiment. When the linear actuator does not require a release function, i.e., in an unreleased state, the brake brakes the ring gear 10, and the ring gear 10 cannot freely rotate. When the driving motor 1 is driven actively, the worm wheel 3 drives the sun gear 11 to rotate, the sun gear 11 drives the planet gears 12 to rotate in the internal gear ring 10, and the planet carrier 13 correspondingly rotates, and the rotation of the lead screw 4 is finally realized because the planet carrier 13 and the lead screw 4 synchronously rotate;

In contrast, in the unreleased state, when the driving motor 1 loses power and the screw 4 drives in the reverse direction, the screw 4 is about to drive the planet carrier 13 to rotate, and since the ring gear 10 cannot rotate freely, the planet carrier 13 can rotate only under the condition that the sun gear 11 rotates, however, the sun gear 11 is kept synchronous with the driving motor 1, so that the screw 4 cannot rotate under the condition that the sun gear 11 does not move, in other words, when the driving motor 1 loses power, the screw 4 cannot rotate in the reverse direction.

However, in this case, when the user needs to rotate the screw rod 4 in the opposite direction even if the driving motor 1 loses power, a release function is required, and in the release state, the brake releases the ring gear 10, and at this time, the ring gear 10 can rotate freely. When the driving motor 1 loses power, the screw rod 4 drives in the reverse direction to drive the planet carrier 13 to rotate, and the sun gear 11 can not rotate at this time, but the inner gear ring 10 can rotate freely at this time, and the planet carrier 13 and the inner gear ring 10 rotate together along the axis of the sun gear 11. In other words, in the released state, even if the drive motor 1 loses power, the screw 4 can be freely rotated.

Therefore, the present embodiment uses the structural characteristics of the planetary gear 12 assembly to complete the release function of the linear actuator, belongs to a new structural concept, and is equivalent to the planetary gear 12 assembly in the present embodiment not only being capable of improving the transmission torque, but also being one part of the release mechanism in the linear actuator, and compared with the conventional release mechanism which requires two additional coupling parts, the release mechanism in the present embodiment does not require two coupling parts, because the ring gear 10 is used as one part of the planetary gear 12 assembly, and simultaneously, the ring gear 10 can simultaneously complete two functions in the present embodiment, so the internal structure of the linear actuator is more compact due to the structural design.

The brake can be in various embodiments, one of the preferred embodiments in the embodiment is specifically developed, the brake in the embodiment comprises a brake worm 14, and an outer gear ring 15 is also arranged in the embodiment, and the outer gear ring 15 and the inner gear ring 10 synchronously rotate, and the outer gear ring 15 and the brake worm 14 are in meshed transmission. When the brake worm 14 can rotate freely, the outer gear ring 15 and the inner gear ring 10 can also rotate freely, and when the brake worm 14 cannot rotate freely, the brake worm 14 can also correspond to the outer gear ring 15 and the inner gear ring 10 and cannot rotate freely, so that the release function of the linear actuator can be realized by controlling the rotation of the brake worm 14.

In this embodiment, the ring gear 10 and the outer ring gear 15 are preferably of an integral structure, the ring gear 10 is radially inside, the outer ring gear 15 is radially outside, the integral structure omits the step of connecting the ring gear 10 and the outer ring gear 15, and of course, those skilled in the art will easily understand that synchronous rotation between the ring gear 10 and the outer ring gear 15 can be achieved by a fixed connection or a spline fit, and such embodiments fall within the scope of the present invention.

The brake is arranged into the structure of the brake worm 14 in the embodiment, firstly, the brake worm 14 is easy to control, the purpose of controlling the brake worm 14 can be achieved by utilizing a brake torsion spring 16 or a coupling and inserting mode, and secondly, the brake worm 14 has another function: the brake worm 14 can also be used as an additional driving mode to drive the linear actuator, because when the driving motor 1 loses power, when the brake worm 14 rotates, the brake worm 14 drives the outer gear ring 15 to correspondingly rotate, the inner gear ring 10 correspondingly rotates, and the sun gear 11 is fixed at the moment, so the inner gear ring 10 rotates to drive the planetary gear 12 and the planet carrier 13 to rotate together, which is equivalent to driving the screw rod 4 to rotate, and the brake adopts the structure of the brake worm 14, so that the brake can be used as an additional driving mode to drive the linear actuator to move under the condition that the driving motor 1 loses power.

For driving the braking worm 14 to rotate, the embodiment further comprises an auxiliary driver for driving the braking worm 14 to rotate, wherein the auxiliary driver is electrically driven or hand-driven. The brake worm 14 can be driven by an additional auxiliary motor, and when the driving motor 1 fails or loses power, the auxiliary motor can be used as an auxiliary power source for driving; the auxiliary drive can of course also be hand-driven, i.e. by hand-shaking the brake worm 14.

It should be noted that, those skilled in the art should know that the structure of the brake is not limited to the description of the embodiment, but may be other embodiments, and reference may be made to the second embodiment.

In order to facilitate locking or unlocking of the brake worm 14, in this embodiment, a switch device for controlling locking or unlocking of the brake worm 14 is preferably provided, as shown in fig. 4, the switch device includes a brake torsion spring 16, a base 17 and a puller 18, the brake torsion spring 16 is sleeved outside the brake worm 14, when the torsion spring inner ring of the brake torsion spring 16 contracts, the brake torsion spring 16 tightly holds the brake worm 14 so as to lock the brake worm 14, otherwise, when the torsion spring inner ring of the brake torsion spring 16 expands, the brake torsion spring 16 hardly generates an acting force on the brake worm 14, and at this time, the brake worm 14 is in an unlocking state and can rotate freely.

Further, advantageously, the braking force of the brake torsion spring 16 on the brake worm 14 can be made adjustable, since the magnitude of the pulling force of the puller 18 on the brake torsion spring 16 determines the magnitude of the deformation of the brake torsion spring 16, with which the user can achieve stepless adjustment between the unreleased state and the released state, whereas conventional switching devices typically only achieve the released state or the unreleased state.

As shown in fig. 4, the specific connection structure of the brake torsion spring 16 in this embodiment: the braking torsion spring 16 comprises a torsion spring main body, a first pin 16a and a second pin 16b, the torsion spring main body is sleeved on the braking worm 14, the first pin 16a is fixed on the base 17, specifically, a jack is arranged on the base 17, and the first pin 16a is inserted into the jack to realize positioning. It should be noted that the base 17 may be a separate component or may be integrally formed with the housing 6, and in this embodiment, it is preferable that the base 17 be a separate component.

The first leg 16a of the braking torsion spring 16 is fixed on the base 17, while the second leg 16b is pulled by the puller 18, and under the pulling action of the puller 18, the braking torsion spring 16 expands radially to release the braking worm 14. The puller 18 may be a guy cable directly connected to the second pin 16b, or may be indirectly connected to the second pin 16b, and in this embodiment, the puller 18 and the second pin 16b are directly provided with a pull rod 19, one end of the pull rod 19 is movably mounted on the base 17, and the other end is fixedly connected to the second pin 16 b.

In order to make the connection between the pull rod 19 and the second pin 16b more convenient and stable, in this embodiment, the pull rod 19 includes a pull rod body and a sleeve 20, and a positioning slot 20a for positioning the second pin 16b is provided on an inner wall of the sleeve 20. The positioning groove 20a is preferably an L-shaped groove, the brake torsion spring 16 is sleeved in the sleeve 20, the second pin 16b is firstly clamped in from one groove of the L-shaped groove, and is positioned in the other groove of the L-shaped groove after rotating for a certain angle, so that the fixation of the second pin 16b is completed. In addition, in order to facilitate the first pin 16a to extend from the sleeve 20, the sleeve 20 is provided with a relief notch 20b for the first pin 16a to extend.

In order to make the rotation of the pull rod 19 smoother, a sliding block 21 is connected between the pull rod 19 and the puller 18, the sliding block 21 is slidably mounted on the base 17, a traveling groove 21a is formed in the sliding block 21, a roller 19a is arranged on the pull rod 19, and the roller 19a is slidably and rotatably matched with the traveling groove 21 a. When the puller 18 pulls the pull rod 19, the roller 19a of the pull rod 19 can slide in the walking groove 21a and also can rotate in the walking groove 21a, so that the pull rod 19 is designed not to interfere when rotating, and meanwhile, the rotating track is more controllable, so that the brake torsion spring 16 is convenient to control.

In this embodiment, the puller 18 includes a cable connected to the slider 21, and a return spring 22 is disposed between the slider 21 and the cable. In the embodiment, two inhaul cables are arranged, and the terminals of the two inhaul cables can be arranged at different positions, so that the operation of a user is facilitated.

As shown in fig. 3, in order to better cover the sliding block 21 and the pull rod 19, the switch device further comprises a box cover 23 in this embodiment, the box cover 23 is connected with the base 17, and the braking torsion spring 16 is installed in the box cover 23. In this embodiment, the lid 23 is hinged to the base 17, and a locking buckle 23a is also provided, and a corresponding buckle hole 17a is provided on the base 17. The box cover 23 can not only shield the parts, but also protect the pull rod 19, the brake torsion spring 16 and other parts.

In addition, in order to reduce the friction force between the brake torsion spring 16 and the brake worm 14 without enclasping, a friction sleeve 24 is arranged between the brake worm 14 and the brake torsion spring 16, the friction sleeve 24 is preferably provided with a notch, when the brake torsion spring 16 is not contracted, the friction force between the brake worm 14 and the friction sleeve 24 is relatively small, and when the brake torsion spring 16 is contracted, the friction sleeve 24 is clamped, and the friction sleeve 24 brakes the brake worm 14 by utilizing the deformation capability of the notch.

The braking mode of the braking worm 14 is not limited to the braking torsion spring 16 in the present embodiment, and it is easily understood by those skilled in the art that a mechanical coupling insertion mode may be adopted, for example, a coupling insert is movably mounted on the base 17, and the coupling insert may be a latch, and the braking worm 14 is provided with a coupling socket matched with the coupling insert, and the coupling insert is inserted into the coupling socket to prevent the braking worm 14 from rotating. This coupling and plugging manner of braking worm 14 is also within the scope of the present invention.

As shown in fig. 5, the linear actuator further includes a gear case 25, the gear case 25 is formed by assembling two half gear cases 25a, the planetary gear 12 assembly is installed in the gear case 25, the brake worm 14 is rotatably installed in the gear case 25, and in order to make the installation of the brake worm 14 more stable, both half gear cases 25a are provided with installation holes 2501 for installing the brake worm 14, so that both ends of the brake worm 14 can be positioned.

With respect to the assembly structure of the planetary gear 12 assembly in the gear case 25, as shown in fig. 6 to 7, the assembly structure of the planetary gear 12 assembly is also optimized and improved in this embodiment, so that the assembly is more compact and has smaller volume, and specifically includes the following steps:

The linear actuator in this embodiment further includes a supporting seat 26, the supporting seat 26 is fixedly connected with a tail pull 27 of the linear actuator, the supporting seat 26 is located at one side of the planetary gear 12 assembly facing the tail pull 27, a first sliding sleeve 28 is sleeved on the supporting seat 26, a first limit check ring 28a is disposed at the tail end of the first sliding sleeve 28, and the sun gear 11 is sleeved on the first sliding sleeve 28 and is axially located between the first limit check ring 28a and the planet carrier 13 or the screw rod 4.

Because the sun gear 11 is assembled through the first sliding sleeve 28 with the first limiting retainer ring 28a, the first sliding sleeve 28 can realize radial positioning and axial positioning on the sun gear 11, compared with a bearing, the structure is more compact, particularly the radial space is smaller, the requirement on the internal space of the gear box 25 can be obviously reduced, the axial positioning function is increased compared with the bearing, in addition, the assembly difficulty is greatly lower than that of the bearing, and the cost of the first sliding sleeve 28 is also greatly lower than that of the bearing.

Meanwhile, in order to facilitate installation of the worm wheel 3, the worm wheel 3 of this embodiment is also installed in a sliding sleeve manner, specifically, the supporting seat 26 includes a center post 29 and an outer ring wall 30 located at the outer side of the center post 29 in the circumferential direction, the first sliding sleeve 28 is sleeved on the center post 29, a second sliding sleeve 31 is sleeved on the outer ring wall 30, and the worm wheel 3 is sleeved on the second sliding sleeve 31. The assembled assembly relationship can be seen in fig. 9, the worm wheel 3 is assembled through the second sliding sleeve 31, the structure is more compact, and the radial space of the second sliding sleeve 31 is smaller. In addition, since the sun gear 11 and the worm gear 3 are assembled on the support base 26 through the first sliding sleeve 28 and the second sliding sleeve 31, respectively, the center post 29 and the peripheral wall are preferably arranged concentrically in the embodiment, so that when the sun gear 11 and the worm gear 3 are mounted on the support base 26 at the same time, the coaxiality of the sun gear 11 and the worm gear 3 can be well ensured, that is, the coaxiality between the worm gear 3 and the sun gear 11 is better, and the transmission precision is better.

Preferably, in this embodiment, the second limiting retainer 31a for preventing the worm wheel 3 from moving towards the tail end is disposed at the tail end of the second sliding sleeve 31, which is equivalent to that the second sliding sleeve 31 can simultaneously realize radial positioning and axial positioning on the worm wheel 3, while the front end of the worm wheel 3 is axially limited by the sun gear 11, the worm wheel 3 is provided with a central hole 3a, the sun gear 11 partially extends into the central hole 3a, the worm wheel 3 is provided with an auxiliary baffle for preventing the sun gear 11 from moving towards the tail end at the central hole 3a, the auxiliary baffle is of a step structure disposed in the central hole 3a, the specific structure is specifically unfolded, the end face of the sun gear 11 abuts against the auxiliary baffle to form axial positioning, in other words, the tail end of the worm wheel 3 is limited by the second limiting retainer 31a of the second sliding sleeve 31, and the front end of the worm wheel 3 is limited by the sun gear 11.

In addition, in this embodiment, the screw rod 4 rotates synchronously with the planet carrier 13, when the sun gear 11 rotates relative to the screw rod 4 and the planet carrier 13, there is a problem of friction or wear between the sun gear 11 and the screw rod 4 or the planet carrier 13, and in order to reduce friction between the sun gear 11 and the screw rod 4 or the planet carrier 13, a friction pad 32 is disposed between the front end of the sun gear 11 and the planet carrier 13 or the screw rod 4, and the wear resistance degree of the friction pad 32 is better. While the friction pad 32 in this embodiment also serves to axially locate the sun gear 11.

In order to facilitate the installation of the friction pad 32, an axially through installation hole is formed in the planet carrier 13, the friction pad 32 and the screw rod 4 are both installed in the installation hole, and the friction pad 32 is axially positioned between the sun gear 11 and the screw rod 4. A schematic view after positioning is completed can be seen in fig. 9.

In addition, as for the assembly mode of the planetary gear 12 assembly, the worm wheel 3, the internal structure of the support base 26 and the gear case 25, the following is preferable as the embodiment:

For the support base 26, the outer ring wall 30 of the support base 26 extends radially outwards to form a collar 26a, the inner wall of the gear box 25 is provided with a clamping groove 2502 for clamping the collar 26a, the collar 26a is in a non-circular structure, the cross section of the collar 26a in this embodiment is preferably octagonal, the clamping groove 2502 is correspondingly shaped, and after the collar 26a is clamped in the clamping groove 2502, the support base 26 cannot rotate freely in the gear box 25.

For the ring gear 10 in the planetary gear 12 assembly, a first ring groove 2503 is provided on the inner wall of the gear case 25, the first ring groove 2503 is located at the front side of the clamping groove 2502, a first convex ring 10a is provided on the outer periphery side of the ring gear 10, and the first convex ring 10a is installed in the first ring groove 2503, so that the ring gear 10 is axially installed on the gear case 25 through the first convex ring 10a and can rotate on the gear case 25.

Of course, as a preferred embodiment, a third sliding sleeve 33 is additionally added between the inner gear ring 10 and the inner wall of the gear case 25, for reducing friction between the inner wall of the gear case 25 and the inner gear ring 10, the outer wall of the third sliding sleeve 33 is installed in the first installation groove, the inner wall of the third sliding sleeve 33 is provided with a second annular groove 3301 matched with the first convex ring 10a, and the third sliding sleeve 33 is composed of two half-ring sleeves 33 a.

For the screw rod 4, a bearing is sleeved outside the screw rod 4, specifically, one half of the bearing is sleeved on the planet carrier 13, the other half of the bearing is sleeved on the screw rod 4 through a bearing sleeve 39, and a bearing groove 2504 for installing a bearing 38 is formed in the inner wall of the gear box 25.

As shown in fig. 6 and 7, in order to make the planetary gear 12 assembly more stable in operation, the present embodiment makes corresponding modifications to the planetary gear 12 assembly, specifically as follows:

The planetary gear 12 assembly further comprises a planetary gear retainer 34, a first positioning hole 34a and a second positioning hole 34b are formed in the planetary gear retainer 34, the planetary gear retainer 34 is fixedly connected with the planetary gear carrier 13 through the second positioning hole 34b, a planetary wheel shaft 40 for installing the planetary gear 12 is arranged on the planetary gear carrier 13, the planetary gear 12 is sleeved on the planetary wheel shaft 40, one end of the planetary wheel shaft 40 is installed on the planetary gear carrier 13, and the other end of the planetary wheel shaft 40 is installed in the second positioning hole 34 b.

The present embodiment improves the planetary gear holder 34, only one end of the conventional planetary axle 40 rotates on the planetary carrier 13, the planetary gear 12 is only fixed to the planetary carrier 13, and the first positioning holes 34a for supporting the planetary axle 40 are provided on the planetary axle in the present embodiment, so that both ends of the planetary axle can be supported, the circle runout of the planetary axle 40 is smaller, the stability is better, and the planetary gear 12 is very stable in the transmission process.

Since there are three planetary gears 12 in the present embodiment, there are three planetary axles 40 in the present embodiment, three first positioning holes 34a are corresponding, and three second positioning holes 34b are preferably disposed between adjacent first positioning holes 34a, so that three second positioning holes 34b are also corresponding in the present embodiment.

In order to prevent the planet axle 40 from coming out of the planet carrier 34, the planet axle 40 is provided with a step at its end facing the planet carrier 34, which step is axially positioned by the planet carrier 34. In order to reduce friction between the end face of the planet gear 12 and the planet gear holder 34, the planet gear holder 34 extends with a convex surrounding edge 34c toward the planet carrier 13 on the peripheral side of the second positioning hole 34b, and after the convex surrounding edge 34c is provided, the end face of the planet gear 12 is only contacted with the convex surrounding edge 34c, so that the contact area can be effectively reduced.

The planetary gear holder 34 is provided with a gear groove 34d for accommodating the planetary gear 12, so as to better keep the planetary gear 12 in place. Since the planetary gear 12 is provided with three gear grooves 34d in this embodiment, the three gear grooves 34d are circumferentially spaced apart, and the first positioning holes 34a are located between adjacent gear grooves 34d, so that the structural design is more compact and reasonable.

In addition, in this embodiment, a unidirectional locking coupling is disposed between the worm wheel 3 and the screw rod 4, and the unidirectional locking coupling is capable of normally transmitting a transmission force when driving rotation in a normal direction, otherwise, when driving rotation in a reverse direction, the unidirectional locking coupling can play a role in locking or preventing the transmission force, and the unidirectional locking coupling plays a role in this embodiment: when the worm wheel 3 is used as a main drive, the screw rod 4 can be normally driven to rotate, otherwise, when the screw rod 4 is used as the main drive, the screw rod 4 can be damped, the screw rod 4 is prevented from continuing to rotate, and the reverse self-locking force of the linear actuator is improved.

The unidirectional locking coupler is also disclosed in the prior mechanical field, in this embodiment, the unidirectional locking coupler is optimized and improved, the coupler comprises a transmission torsion spring 35 and a damping ring sleeved with the transmission torsion spring 35, the worm wheel 3 transmits torque to the transmission torsion spring 35 in a driving state and the screw rod 4 is driven state, the transmission torsion spring 35 is in clearance fit with the damping ring, and the screw rod 4 transmits torque to the transmission torsion spring 35 in a driving state and the screw rod 4 is in interference fit with the damping ring in a driving state. The cooperation of the transmission torsion spring 35 and the damping ring is very low in cost, and meanwhile, compared with a traditional coupler, the cooperation of the transmission torsion spring 35 and the damping ring is small in size and low in requirement on the internal space of the linear actuator.

As shown in fig. 6 to 8, in this embodiment, the specific structure of the unidirectional locking coupling is as follows:

The shaft coupling includes first plectrum 36, the second plectrum 37 that circumference interval set up, and first plectrum 36 is used for being connected with worm wheel 3, and second plectrum 37 is used for being connected with the transmission of lead screw 4, and in this embodiment, second plectrum 37 is connected with sun gear 11 to indirectly realize being connected with the transmission of lead screw 4, transmission torsional spring 35 suit is on first plectrum 36 and second plectrum 37, and transmission torsional spring 35 includes the pin 35a of bending, the pin 35a of bending clamps between first plectrum 36 and second plectrum 37.

In this embodiment, the transmission torsion spring 35 is sleeved outside the first shifting plate 36 and the second shifting plate 37, the damping ring is sleeved outside the transmission torsion spring 35, the bending pin 35a of the transmission torsion spring 35 is bent radially inwards, and when the first shifting plate 36 transmits torque to the transmission torsion spring 35, the bending pin 35a is shifted towards the screwing direction of the transmission torsion spring 35.

When the transmission torsion spring 35 is stirred in different directions, two states can occur, one is a contraction direction, the other is an outward expansion direction, when the first plectrum 36 drives the transmission torsion spring 35, the transmission torsion spring 35 can radially contract, so that a gap between the outer periphery side of the transmission torsion spring 35 and the damping ring becomes large, friction can be considered between the transmission torsion spring 35 and the damping ring at the moment, and the state transmission torsion spring 35 holds the first plectrum 36 and the second plectrum 37 to rotate simultaneously, which is equivalent to that the worm wheel 3 can normally drive the sun gear 11 to rotate.

Conversely, when the transmission torsion spring 35 is reversely stirred, namely, the first poking piece 36 is passive, the second poking piece 37 is active, and at the moment, the second poking piece 37 transmits torque to the transmission torsion spring 35, the bending pin 35a is stirred towards the unscrewing direction of the transmission torsion spring 35, the transmission torsion spring 35 can be radially outwards expanded, interference fit between the transmission torsion spring 35 and the damping ring after the radial outwards expansion occurs, so that damping is generated, and at the moment, the damping ring can prevent the transmission torsion spring 35 from continuously rotating, namely, the damping ring can prevent the second poking piece 37 from continuously rotating.

In other words, when the worm wheel 3 is driven as a main drive, the screw 4 can be driven normally, and when the screw 4 is driven as a main drive, the worm wheel 3 cannot be driven to rotate, which corresponds to the drive of the sun gear 11. Only one-way transmission can be completed.

In order to enable the first shifting sheet 36 and the second shifting sheet 37 to be better matched with the transmission torsion spring 35, a central hole 3a is formed in the center of the worm wheel 3, the first shifting sheet 36 is a first arc sheet arranged along the circumferential direction of the central hole, the second shifting sheet 37 is a second arc sheet protruding in the axial direction on the sun gear 11, and meanwhile, the matching of the first arc sheet and the second arc sheet is at the position of the central hole 3a of the worm wheel 3, which is equivalent to the fact that a coupling part is arranged at the center of the worm wheel 3, the axial position is overlapped with the worm wheel 3, and the axial length of the whole structure is reduced.

It should be noted that, in this embodiment, the inner diameter of the first arc-shaped piece is smaller than the inner diameter of the central hole 3a, when the sun gear 11 partially passes through the central hole 3a, the end face of the sun gear 11 will be blocked by the first arc-shaped piece, and the first arc-shaped piece acts as the auxiliary blocking piece in the above description, which is equivalent to that in this embodiment, the auxiliary blocking piece of the worm wheel 3 to the sun gear 11 is the first arc-shaped piece.

When in assembly, the second arc-shaped sheet passes through the central hole and forms a round surrounding wall with a notch together with the first arc-shaped sheet, the transmission torsion spring 35 is sleeved outside the round surrounding wall, and the bending pin 35a of the transmission torsion spring 35 is clamped in the notch. In this embodiment, in order to be more stable in transmission, the both ends of transmission torsional spring 35 are equipped with pin 35a of bending respectively, are equivalent to transmission torsional spring 35 and possess two pin 35a of bending, and first arc piece and second arc piece just constitute two breach when the equipment, and two pin 35a of bending just can block in two breach.

In this embodiment, the damping ring is preferably the outer ring wall 30 on the supporting seat 26, and the driving torsion spring 35 is sleeved in the outer ring wall 30, so that the additional design of the damping ring, which is equivalent to the outer ring wall 30 in this embodiment, can be omitted, two functions are provided, the outer peripheral side wall of the damping ring can be used for positioning the sleeved worm wheel 3, the inner peripheral side wall of the damping ring can be used for generating damping action with the driving torsion spring 35, and thus, the design components are fewer, the structure is more compact, and meanwhile, the assembly is convenient.

Example two

The difference between the embodiment and the first embodiment is that the embodiment adopts a brake worm to brake the ring gear, in the embodiment, an outer ring gear torsion spring is directly sleeved outside the ring gear, and the outer ring gear torsion spring is directly pulled by a guy cable to realize radial contraction or radial expansion of the outer ring gear torsion spring, and when the outer ring gear torsion spring radially contracts, the ring gear is braked, so that the embodiment is an alternative scheme of the brake.

Example III

The difference between the first embodiment and the second embodiment is that the one-way locking coupling structure between the worm and the screw rod is different, in this embodiment, the transmission torsion spring is sleeved in the first shifting piece and the second shifting piece, the damping ring is sleeved in the transmission torsion spring, in other words, the damping ring is located at the innermost side, the first shifting piece and the second shifting piece are located at the outermost side, and the transmission torsion spring is located between the damping ring and the first shifting piece and the second shifting piece.

The pin of bending of transmission torsional spring in this embodiment is radial outwards bending, and when first plectrum was to transmission torsional spring transmission moment of torsion, the pin of bending was stirred towards transmission torsional spring unscrewing direction, and when the second plectrum was to transmission torsional spring transmission moment of torsion, the pin of bending was stirred towards transmission torsional spring direction of screwing, and theory of operation is as follows:

When the first plectrum is used as a drive, the transmission torsion spring expands radially outwards, and the gap between the inner side of the transmission torsion spring and the outer side of the damping ring is enlarged, so that the friction force between the transmission torsion spring and the damping ring is reduced, and the transmission torsion spring can rotate freely, so that the transmission torsion spring can drive the first plectrum and the second plectrum to rotate together;

When the second shifting piece is used as a drive, the torsion spring radially contracts, and at the moment, the inner side of the transmission torsion spring is in interference fit with the damping ring, so that the damping ring can be considered to prevent the transmission torsion spring from rotating, and at the moment, the second shifting piece is prevented from rotating.

Due to this implementation in this embodiment, a separate damping ring is required on the support base, which may preferably be provided between the center post and the outer collar wall.

While the invention has been described in terms of embodiments, it will be appreciated by those skilled in the art that the invention is not limited thereto but rather includes the drawings and the description of the embodiments above. Any modifications which do not depart from the functional and structural principles of the present invention are intended to be included within the scope of the appended claims.

Claims

1. The utility model provides a linear actuator, includes driving motor, drive worm, worm wheel, lead screw, nut, and driving motor connects drive worm, and drive worm drives the worm wheel rotation, and the worm wheel rotation drives the lead screw and rotates, and the lead screw rotates and drives nut axial displacement, its characterized in that still includes:

The planetary gear assembly is arranged between the worm wheel and the screw rod and comprises an annular gear, a sun gear, a planetary gear and a planetary carrier, wherein the sun gear and the worm wheel synchronously rotate, and the planetary carrier and the screw rod synchronously rotate; the linear actuator further includes a gear box, the planetary gear assembly being mounted within the gear box;

A brake for braking the ring gear to restrict free rotation thereof; the linear actuator further comprises an outer gear ring, the outer gear ring and the inner gear ring synchronously rotate, and the outer gear ring is meshed with a brake worm; the brake worm is sleeved with a brake torsion spring, and the brake torsion spring contracts the torsion spring inner ring or enlarges the torsion spring inner ring so as to lock or unlock the brake worm;

The linear actuator further comprises a base and a puller, the braking torsion spring comprises a torsion spring main body, a first pin and a second pin, the torsion spring main body is sleeved on the braking worm, the first pin is fixed on the base, the second pin is pulled by the puller, and under the pulling action of the puller, the braking torsion spring radially expands to release the braking worm.

2. The linear actuator of claim 1, wherein the inner and outer ring gears are of unitary construction.

3. The linear actuator of claim 1, wherein a pull rod is disposed between the puller and the brake torsion spring, the pull rod being rotatably mounted on the base, the second pin being positionally mounted on the pull rod.

4. A linear actuator as claimed in claim 3 wherein the tie rod comprises a tie rod body and a sleeve, the inner wall of the sleeve being provided with a locating slot for locating the second pin.

5. A linear actuator as claimed in claim 3 wherein a slider is connected between the pull rod and the puller, the slider being slidably mounted on the base, the slider being provided with a travel slot, the pull rod being provided with a roller which is slidably and rotatably engaged with the travel slot.

6. The linear actuator of claim 1, wherein a friction sleeve is provided between the brake worm and the brake torsion spring.

7. The linear actuator of claim 1, wherein the linear actuator is movably mounted with a coupling insert, the brake worm is provided with a coupling socket for mating with the coupling insert, and the coupling insert is inserted into the coupling socket to prevent rotation of the brake worm.

8. The linear actuator of claim 1, wherein the brake worm is rotatably mounted within a gear box.

9. The linear actuator of claim 1, wherein the sun gear is positioned at the center of the ring gear, at least one planet gear is meshed between the sun gear and the ring gear, the planet gear is mounted on the planet carrier, and the planet carrier is fixedly connected with the screw rod.

10. The linear actuator of claim 1, further comprising an auxiliary drive that drives rotation of the brake worm, the auxiliary drive being either an electric drive or a hand drive.

11. The linear actuator of claim 1, wherein the brake comprises an outer ring gear torsion spring nested outside the ring gear.

12. The linear actuator of claim 1, wherein a unidirectional locking coupling is arranged between the worm wheel and the sun gear, the coupling comprises a transmission torsion spring and a damping ring sleeved with the transmission torsion spring, the worm wheel transmits torque to the transmission torsion spring and enables the transmission torsion spring to be in clearance fit with the damping ring in a worm wheel driving and sun gear driven state, and the screw rod transmits torque to the transmission torsion spring and enables the transmission torsion spring to be in interference fit with the damping ring in a worm wheel driven and sun gear driving state.

13. The linear actuator of claim 12, wherein the coupling comprises a first paddle and a second paddle circumferentially spaced apart, the first paddle being adapted to be coupled to the worm gear and the second paddle being adapted to be coupled to the sun gear, the drive torsion spring being sleeved on the first paddle and the second paddle, the drive torsion spring comprising a bent pin captured between the first paddle and the second paddle.

14. The linear actuator of claim 13, wherein the drive torsion spring is sleeved outside the first pulling piece and the second pulling piece, the damping ring is sleeved outside the drive torsion spring, the bending pin of the drive torsion spring is bent radially inwards, and when the first pulling piece transmits torque to the drive torsion spring, the bending pin is pulled towards the screwing direction of the drive torsion spring.

15. The linear actuator of claim 14, wherein the worm gear has a central hole in the center, the first paddle is a first arcuate tab circumferentially disposed about the central hole, and the second paddle is a second arcuate tab axially projecting from the sun gear, the second arcuate tab passing through the central hole and forming a notched circular enclosure with the first arcuate tab.

16. The linear actuator of claim 1, further comprising a support base disposed on a side of a rear end of the planetary gear assembly, wherein a first sliding sleeve is sleeved on the support base, a first limit retainer ring is disposed on a rear end of the first sliding sleeve, and the sun gear is sleeved on the first sliding sleeve and axially positioned between the first limit retainer ring and the planet carrier or the screw rod.

17. The linear actuator of claim 16, wherein a friction pad is provided between the front end of the sun gear and the planet carrier or lead screw.

18. The linear actuator of claim 16, wherein the support comprises a center post and an outer collar wall circumferentially outward of the center post, the first sliding sleeve being fitted over the center post, the outer collar wall being fitted with a second sliding sleeve, the worm gear being fitted over the second sliding sleeve.